###### Accueil » Publications dans le domaines des technologies » 10-2017
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 Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 10-2017 trié par par titre, page: 1
» A New CMTF Evaluation Model for Dynamic Target in Photoelectric Imaging System
 Résumé:To evaluate the reliability of photoelectric imaging system, it is essential to research the influences of the illumination contrast and the modulation transfer functions (MTF) to the system imaging capability. This paper deduces a new illumination contrast model based on the optical geometry structure and the optical reflection characteristics of dynamic target; according to the photoelectric imaging principle, defines the system’s MTF by the form of some imaging links, including the optical characteristics, the CCD detector, and the atmospheric characteristics; establishes a new contrast modulation transfer functions (CMTF) mathematical model based on the analysis of the illumination contrast and MTF; obtains the expression of magnitude to evaluate the effects of some key factors to imaging capability. Through the calculation and analysis, under various conditions, with the increasing of target reflectivity, relative aperture, atmospheric coherence length, and optical transmittance, the system imaging capability shows a general trend of rising; with the increasing of background radiation illumination, target distance, standard deviation, and the system imaging capability shows attenuation trend; the results show that different factors have a great impact on the imaging capability, which proves the suitability of CMTF model for evaluating the performance photoelectric system. Auteurs: Hanshan Li;Sangsang Chen; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6571 - 6577 Editeur: IEEE Document complet vers site de l'éditeur
» A New Framework for Quality Assessment of High-Resolution Fingerprint Images
 Résumé:The quality assessment of sets of features extracted from patterns of epidermal ridges on our fingers is a biometric challenge problem with implications on questions concerning security, privacy and identity fraud. In this work, we introduced a new methodology to analyze the quality of high-resolution fingerprint images containing sets of fingerprint pores. Our approach takes into account the spatial interrelationship between the considered features and some basic transformations involving point process and anisotropic analysis. We proposed two new quality index algorithms following spatial and structural classes of analysis. These algorithms have proved to be effective as a performance predictor and as a filter excluding low-quality features in a recognition process. The experiments using error reject curves show that the proposed approaches outperform the state-of-the-art quality assessment algorithm for high-resolution fingerprint recognition, besides defining a new method for reconstructing their friction ridge phases in a very consistent way. Auteurs: Raoni F. S. Teixeira;Neucimar J. Leite; Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence Date publication: 10.-2017, volume: 39, issue:10, pages: 1905 - 1917 Editeur: IEEE Document complet vers site de l'éditeur
» A New Method for Automatic Sleep Stage Classification
 Résumé:Traditionally, automatic sleep stage classification is quite a challenging task because of the difficulty in translating open-textured standards to mathematical models and the limitations of handcrafted features. In this paper, a new system for automatic sleep stage classification is presented. Compared with existing sleep stage methods, our method can capture the sleep information hidden inside electroencephalography (EEG) signals and automatically extract features from raw data. To translate open sleep stage standards into machine rules recognized by computers, a new model named fast discriminative complex-valued convolutional neural network (FDCCNN) is proposed to extract features from raw EEG data and classify sleep stages. The new model combines complex-valued backpropagation and the Fisher criterion. It can learn discriminative features and overcome the negative effect of imbalance dataset. More importantly, the orthogonal decision boundaries for the real and imaginary parts of a complex-valued convolutional neuron are proven. A speed-up algorithm is proposed to reduce computational workload and yield improvements of over an order of magnitude compared to the normal convolution algorithm. The classification performances of handcrafted features and different convolutional neural networks are compared with that of the FDCCNN. The total accuracy and kappa coefficient of the proposed method are 92% and 0.84, respectively. Experiment results demonstrated that the performance of our system is comparable to those of human experts. Auteurs: Junming Zhang;Yan Wu; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1097 - 1110 Editeur: IEEE Document complet vers site de l'éditeur
» A New Small-Signal Parameter Extraction Technique for Large Gate-Periphery GaN HEMTs
 Résumé:In this letter, we propose a method to extract the small-signal equivalent circuit model for GaN HEMTs using extrinsic-level RF broadband (0.5–50 GHz) Z-parameters. The measured Z-parameters of large gate-periphery GaN devices exhibit certain interesting characteristics, due to their inherently larger intrinsic capacitances and their subsequent interaction with the extrinsic inductances. We exploit these characteristics to simultaneously extract the intrinsic as well as the extrinsic small-signal model components and successfully validate it with measured S-parameter data for a $10~\times90~\mu \text{m}$ GaN device. Auteurs: Sheikh Aamir Ahsan;Ahtisham-ul-Haq Pampori;Sudip Ghosh;Sourabh Khandelwal;Yogesh Singh Chauhan; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 918 - 920 Editeur: IEEE Document complet vers site de l'éditeur
» A New Three-Dimensional Sliding Mode Guidance Law Variation With Finite Time Convergence
 Résumé:This paper develops a new three-dimensional (3-D) guidance law which guarantees the interception of manoeuvring targets in a finite time. The new guidance law accepts the concept that nullifying the line-of-sight rate guarantees the interception of the target and its derivation is based on finite time sliding mode guidance. By using a 3-D kinematic equation set constructed in a rotating coordinate system, the proposed guidance law alleviates an issue of general 3-D guidance caused by the cross coupling effect between pitch and yaw planes. In theoretical analysis, finite time convergence of the new guidance law is proved and compared with that of a practical sliding mode guidance law. Characteristics such as energy consumption and convergence boundary layer are also theoretically analyzed. Simulation results demonstrate that the new guidance law effectively intercepts manoeuvring targets in a finite time and analysis results are valid. Auteurs: Hyo-Sang Shin;Antonios Tsourdos;Ke-Bo Li; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2221 - 2232 Editeur: IEEE Document complet vers site de l'éditeur
» A New View of Multi-User Hybrid Massive MIMO: Non-Orthogonal Angle Division Multiple Access
 Résumé:This paper presents a new view of multi-user (MU) hybrid massive multiple-input and multiple-output (MIMO) systems from array signal processing perspective. We first show that the instantaneous channel vectors corresponding to different users are asymptotically orthogonal if the angles of arrival of users are different. We then decompose the channel matrix into an angle domain basis matrix and a gain matrix. The former can be formulated by steering vectors and the latter has the same size as the number of RF chains, which perfectly matches the structure of hybrid precoding. A novel hybrid channel estimation is proposed by separately estimating the angle information and the gain matrix, which could significantly save the training overhead and substantially improve the channel estimation accuracy compared with the conventional beamspace approach. Moreover, with the aid of the angle domain matrix, the MU massive MIMO system can be viewed as a type of non-orthogonal angle division multiple access to simultaneously serve multiple users at the same frequency band. Finally, the performance of the proposed scheme is validated by computer simulation results. Auteurs: Hai Lin;Feifei Gao;Shi Jin;Geoffrey Ye Li; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 10.-2017, volume: 35, issue:10, pages: 2268 - 2280 Editeur: IEEE Document complet vers site de l'éditeur
» A New Way for a New Generation [Editorial]
 Résumé:Presents the introductory editorial for this issue of the publication. Auteurs: Cristian Quintero; Apparue dans: IEEE Potentials Date publication: 10.-2017, volume: 36, issue:5, pages: 3 - 3 Editeur: IEEE Document complet vers site de l'éditeur
» A Noise-Power-Area Optimized Biosensing Front End for Wireless Body Sensor Nodes and Medical Implantable Devices
 Résumé:In this paper, we present a noise, power, and area efficient biosensing front-end application specified integrated circuit (ASIC) for the next-generation wireless body sensor nodes and implantable devices. We identify the key design parameter tradeoffs in the biomedical recording systems and carry out a thorough analysis and optimization to maximize them. Based on our analysis and optimization of the front end, we propose a design methodology for the recording channel that is applicable to various biomedical applications. The ASIC is implemented in a 0.18- $\mu \text{m}$ CMOS process to validate our optimization methodology. The ASIC is reconfigurable to accommodate various biopotentials with the high-pass and low-pass cutoff frequencies being 0.5–300 Hz and 150 Hz–10 kHz, respectively. The low-pass cutoff is provided by an ultralow power $G_{m}$ - ${C}$ low-pass filter, which also acts as an antialiasing filter for the switching-optimized 10-b successive approximation register (SAR) analog-to-digital converter (ADC). The analog front end (AFE) gain is also programmable from 38 to 72 dB. A comprehensive power management unit provides the power supply, multiple reference voltages, and bias currents to the entire chip. The AFE and ADC dissipate only $5.74~\mu \text{W}$ and 306 nW from the on-chip regulators, respectively. The measured input-referred noise is $2.98~\mu \text{V}_{{\text {rms}}}$ , resulting in the noise efficiency factor and power efficiency factor equals 2.6 and 9.46, respectively. The active area of the AFE is 0.0228 mm2. We verify the chip - unctionality in a number of in vivo and ex vivo biological experiments. Auteurs: Hansraj Bhamra;John Lynch;Matthew Ward;Pedro Irazoqui; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2917 - 2928 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Approach to Subpixel Land-Cover Change Detection Based on a Supervised Back-Propagation Neural Network for Remotely Sensed Images With Different Resolutions
 Résumé:Extracting subpixel land-cover change detection (SLCCD) information is important when multitemporal remotely sensed images with different resolutions are available. The general steps are as follows. First, soft classification is applied to a low-resolution (LR) image to generate the proportion of each class. Second, the proportion differences are produced by the use of another high-resolution (HR) image and used as the input of subpixel mapping. Finally, a subpixel sharpened difference map can be generated. However, the prior HR land-cover map is only used to compare with the enhanced map of LR image for change detection, which leads to a nonideal SLCCD result. In this letter, we present a new approach based on a back-propagation neural network (BPNN) with a HR map (BPNN_HRM), in which a supervised model is introduced into SLCCD for the first time. The known information of the HR land-cover map is adequately employed to train the BPNN, whether it predates or postdates the LR image, so that a subpixel change detection map can be effectively generated. In order to evaluate the performance of the proposed algorithm, it was compared with four state-of-the-art methods. The experimental results confirm that the BPNN_HRM method outperforms the other traditional methods in providing a more detailed map for change detection. Auteurs: Ke Wu;Yanfei Zhong;Xianmin Wang;Weiwei Sun; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1750 - 1754 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Approximation for K Distribution: Closed-Form BER Using DPSK Modulation in Free-Space Optical Communication
 Résumé:A new analytical approximate expression for K distribution is proposed by expanding it in terms of orthogonal associated Laguerre polynomial. The expansion is truncated after first three terms, which yields a fairly close approximation to K distribution. The advantage of the proposed approximation is that the analytical closed form expression for bit error rate can be easily derived. KL measure is used to show the accuracy of the proposed approximation. The proposed approximate probability density function and bit error rate work well within the desired range of the channel parameter $\alpha$ , which is $1 < \alpha < 2$ and corresponds to the scintillation index value ranging from 2 to 3. We have also demonstrated the utility of our approximation for other quality of service metric such as fade probability. Auteurs: Rajeev Kumar Singh; Karmeshu;Santosh Kumar; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 14 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel CH5 Inverter for Single-Phase Transformerless Photovoltaic System Applications
 Résumé:Versatile single-phase voltage source inverters with unipolar voltage pulse and leakage current elimination capability have been extensively investigated for transformerless PV systems in the literature. However, the innovative current source inverters with leakage current elimination capability are not well explored. In this brief, a novel single-phase current source H5 (CH5) inverter is proposed. Only one extra IGBT is needed, but the leakage current can be significantly suppressed with a novel space vector modulation. Finally, the experimental tests are carried out on a single-phase CH5 inverter and the experimental results verify the effectiveness of the proposed topology and space vector modulation. Auteurs: Xiaoqiang Guo; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1197 - 1201 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Fabrication Technique for MEMS Based on Agglomeration of Powder by ALD
 Résumé:This paper describes a novel fabrication technique for microelectromechanical systems (MEMS) based on the agglomeration of micron-sized powder into rigid 3-D porous structures by means of atomic layer deposition (ALD). Since ALD is performed at low temperatures, such structures can be created from a broad variety of materials. It is shown that the compatibility of substrates with embedded porous structures to common back-end-of-line environment can be regained, and post-processed by applying standard processes of MEMS and integrated circuit technology is possible. In such a way, for the first time, nearly any material can be integrated onto silicon substrates in a simple and generic way. Moreover, not only a particular porosity or internal surface can be targeted. The bulk properties of the structure can be tailored as well, which opens up unique prospects for the future of MEMS. Auteurs: T. Lisec;T. Reimer;M. Knez;S. Chemnitz;A. V. Schulz-Walsemann;A. Kulkarni; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1093 - 1098 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel High Bandwidth Current Control Strategy for SiC mosfet Based Active Front-End Rectifiers Under Unbalanced Input Voltage Conditions
 Résumé:SiC mosfet based converters are capable of high switching frequency operation. In this paper, the converter is operated with 50-kHz switching frequency for an active front-end rectifier application. Due to high switching frequency, the grid-side filter size is reduced, and the possibility of a high bandwidth current control loop is utilized in this paper. A current control loop with bandwidth of 5 kHz is designed using a proportional-integral controller in synchronously rotating dq-reference frame. In addition, the performance of the controller is tested under unbalanced input supply conditions. During this condition, new feed-forward signals, which are added to the controller output, are proposed. The gain of the feed-forward signal can be modified to achieve balanced sinusoidal grid currents, constant dc-link voltage, or a controlled negative-sequence input current, which are typical application-depending requirements. A closed-form formula to calculate the gain of the feed-forward signal to achieve the above-mentioned requirements is also proposed in this paper. To verify the proposed method, the simulation and experimental results are presented in this paper. Auteurs: Ramkrishan Maheshwari;Ionut Trintis;Lajos Török;Stig Munk-Nielsen;Philip James Douglass;Lorand Bede; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8310 - 8320 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Hybrid Five-Level Voltage-Source Converter Based on T-Type Topology for High-Efficiency Applications
 Résumé:A novel hybrid five-level voltage-source converter for high-efficiency applications is investigated in this paper. Compared with traditional multilevel converters, this hybrid multilevel converter generates desired staircase voltage levels with a reduced number of power devices and isolated drivers at higher voltage levels. It has redundant switching state combinations in hybrid multilevel converter, which makes it easy to balance flying capacitor voltages and realize fault-tolerant operation. A voltage-balancing control strategy based on switching state redundancies is presented for the hybrid multilevel converter to generate desired levels and also keep voltage balance of flying capacitors at the same time. The performance of the hybrid multilevel converter under various operating conditions is investigated in MATLAB/Simulink. The effectiveness of the proposed hybrid multilevel converter is validated by experiment results. Auteurs: Shuai Xu;Jianzhong Zhang;Xing Hu;Yongjiang Jiang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4730 - 4743 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Hybrid Islanding Detection Method for Inverter-Based DGs Using SFS and ROCOF
 Résumé:This paper is aimed at proposing a new hybrid method for the islanding detection of distributed-generation (DG) units. Hybrid method operation is based on the combination of an active and a passive method, for which the optimized Sandia frequency shift (SFS) method is used as the selected active method, and rate of change of frequency relay (ROCOF) is used as the passive method. In order to demonstrate the effectiveness of the proposed technique on islanding detection, several simulation studies based on IEEE 1547 and UL1741 anti-islanding test requirements are carried out. The evaluation of simulation results reveals that the control system, based on the proposed hybrid algorithm, meets the DG islanding protection requirements efficiently. Moreover, it will be demonstrated that the proposed hybrid method is capable of accurately operating under multiple DG units, load switching in the grid-connected mode, as well as different load quality factor conditions. Auteurs: Mahdiyeh Khodaparastan;Hesan Vahedi;Farid Khazaeli;Hashem Oraee; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2162 - 2170 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Hybrid Kinect-Variety-Based High-Quality Multiview Rendering Scheme for Glass-Free 3D Displays
 Résumé:This paper presents a new hybrid Kinect-variety-based synthesis scheme that renders artifact-free multiple views for autostereoscopic/automultiscopic displays. The proposed approach does not explicitly require dense scene depth information for synthesizing novel views from arbitrary viewpoints. Instead, the integrated framework first constructs a consistent minimal image–space parameterization of the underlying 3D scene. The compact representation of scene structure is formed using only implicit sparse depth information of a few reference scene points extracted from raw RGB depth data. The views from arbitrary positions can be inferred by moving the novel camera in parameterized space by enforcing Euclidean constraints on reference scene images under a full-perspective projection model. Unlike the state-of-the-art depth image-based rendering (DIBR) methods, in which input depth map accuracy is crucial for high-quality output, our proposed algorithm does not depend on precise per-pixel geometry information. Therefore, it simply sidesteps to recover and refine the incomplete or noisy depth estimates with advanced filling or upscaling techniques. Our approach performs fairly well in unconstrained indoor/outdoor environments, where the performance of range sensors or dense depth-based algorithms could be seriously affected due to scene complex geometric conditions. We demonstrate that the proposed hybrid scheme provides guarantees on the completeness, optimality with respect to the inter-view consistency of the algorithm. In the experimental validation, we performed a quantitative evaluation as well as subjective assessment of the scene with complex geometric or surface properties. A comparison with the latest representative DIBR methods is additionally performed to demonstrate the superior performance of the proposed scheme. Auteurs: Mansi Sharma;Santanu Chaudhury;Brejesh Lall; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2098 - 2117 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Intracranial Pressure Readout Circuit for Passive Wireless LC Sensor
 Résumé:We present a wide frequency range, low cost, wireless intracranial pressure monitoring system, which includes an implantable passive sensor and an external reader. The passive sensor consists of two spiral coils and transduces the pressure change to a resonant frequency shift. The external portable reader reads out the sensor's resonant frequency over a wide frequency range (35 MHz–2.7 GHz). We propose a novel circuit topology, which tracks the system's impedance and phase change at a high frequency with low-cost components. This circuit is very simple and reliable. A prototype has been developed, and measurement results demonstrate that the device achieves a suitable measurement distance (>2 cm), sufficient sample frequency (>6 Hz), fine resolution, and good measurement accuracy for medical practice. Responsivity of this prototype is 0.92 MHz/mmHg and resolution is 0.028 mmHg. COMSOL specific absorption rate simulation proves that this system is safe. Considerations to improve the device performance have been discussed, which include the size of antenna, the power radiation, the Analog-to-digital converter (ADC) choice, and the signal processing algorithm. Auteurs: Fa Wang;Xuan Zhang;Mehdi Shokoueinejad;Bermans J. Iskandar;Joshua E. Medow;John G. Webster; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1123 - 1132 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Ionospheric Sounding Radar Based on USRP
» A Novel Methodology to Label Urban Remote Sensing Images Based on Location-Based Social Media Photos
 Résumé:With the rapid development of the internet and popularization of intelligent mobile devices, social media is evolving fast and contains rich spatial information, such as geolocated posts, tweets, photos, video, and audio. Those location-based social media data have offered new opportunities for hazards and disaster identification or tracking, recommendations for locations, friends or tags, pay-per-click advertising, etc. Meanwhile, a massive amount of remote sensing (RS) data can be easily acquired in both high temporal and spatial resolution with a multiple satellite system, if RS maps can be provided, to possibly enable the monitoring of our location-based living environments with some devices like charge-coupled device (CCD) cameras but on a much larger scale. To generate the classification maps, usually, labeled RS image pixels should be provided by RS experts to train a classification system. Traditionally, labeled samples are obtained according to ground surveys, image photo interpretation or a combination of the aforementioned strategies. All the strategies should be taken care of by domain experts, in a means which is costly, time consuming, and sometimes of a low quality due to reasons such as photo interpretation based on RS images only. These practices and constraints make it more challenging to classify land-cover RS images using big RS data. In this paper, a new methodology is proposed to classify urban RS images by exploiting the semantics of location-based social media photos (SMPs). To validate the effectiveness of this methodology, an automatic classification system is developed based on RS images as well as SMPs via big data analysis techniques including active learning, crowdsourcing, shallow machine learning, and deep learning. As the labels of RS training data are given by ordinary people with a crowdsourcing technique, the developed system is named Crowd4RS. The quantitative and qualitative experiments confirm the effectiveness of the proposed- Crowd4RS system as well as the proposed methodology for automatically generating RS image maps in terms of classification results based on big RS data made up of multispectral RS images in a high spatial resolution and a large amount of photos from social media sites, such as Flickr and Panoramio. Auteurs: Mingmin Chi;Zhongyi Sun;Yiqing Qin;Jinsheng Shen;Jón Atli Benediktsson; Apparue dans: Proceedings of the IEEE Date publication: 10.-2017, volume: 105, issue:10, pages: 1926 - 1936 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Model for Direction Finding and Phase Center With Practical Considerations
 Résumé:The data model for direction of arrival (DOA) estimation is revisited and studied with more attention to the practical implementation of the antenna arrays and verified through measurement results. A complete data model for a single-channel direction finding system that includes, for the first time, the effects of the switching mechanism among antennas is presented. In order to combat coupling among antenna elements and the radio frequency switch nonidealities, a comprehensive model is developed, which includes more accurate noise modeling. The effect of the phase center (PC) in DOA estimation is then discussed and an improved data model is presented, which includes the antenna’s PC movement. The Cramer–Rao bound for circular arrays including the newly introduced parameter for the PC is derived. The new model shows significant improvement in the estimation accuracy. Auteurs: Evangelos Kornaros;Saman Kabiri;Franco De Flaviis; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5475 - 5491 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Nanoparticle Mediated Selective Inner Retinal Photocoagulation for Diseases of the Inner Retina
 Résumé:A novel nanoparticle mediated methodology for laser photocoagulation of the inner retina to achieve tissue selective treatment is presented. Methods: Transport of 527, 577, and 810 nm laser, heat deposition, and eventual thermal damage in vitreous, retina, RPE, choroid, and sclera were modeled using Bouguer–Beer–Lambert law of absorption and solved numerically using the finite volume method. Nanoparticles were designed using Mie theory of scattering. Performance of the new photocoagulation strategy using gold nanospheres and gold–silica nanoshells was compared with that of conventional methods without nanoparticles. For experimental validation, vitreous cavity of ex vivo porcine eyes was infused with gold nanospheres. After ~6 h of nanoparticle diffusion, the porcine retina was irradiated with a green laser and imaged simultaneously using a spectral domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering). Results: Our computational model predicted a significant spatial shift in the peak temperature from RPE to the inner retinal region when infused with nanoparticles. Arrhenius thermal damage in the mid-retinal location was achieved in ~14 ms for 527 nm laser thereby reducing the irradiation duration by ~30 ms compared with the treatment without nanoparticles. In ex vivo porcine eyes infused with gold nanospheres, SD-OCT retinal images revealed a lower thermal damage and expansion at RPE due to laser photocoagulation. Conclusion: Nanoparticle infused laser photocoagulation strategy provided a selective inner retinal thermal damage with significant decrease in laser power and laser exposure time. Significance: The proposed treatment strategy shows possibilities for an efficient and highly selective inner retinal laser treatment. Auteurs: Rupesh Singh;Srinivas Rajaraman;Madhusudhanan Balasubramanian; Apparue dans: IEEE Transactions on NanoBioscience Date publication: 10.-2017, volume: 16, issue:7, pages: 542 - 554 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Radio-Over-Fiber System Based on Carrier Suppressed Frequency Eightfold Millimeter Wave Generation
 Résumé:We propose a novel and simple scheme for photonic frequency eightfold millimeter wave (mm-wave) generation with optical carrier suppression based on only one single-drive Mach–Zehnder modulator (MZM). According to our theoretical analysis and experimental demonstration, by adopting designed direct current bias voltage of MZM and the amplitude voltage of the radio frequency (RF) drive signal, two fourth-order optical subcarriers are generated via a single-drive MZM. Furthermore, the corresponding optical central carrier and undesired sidebands are suppressed simultaneously. Based on our proposed scheme, the generation of 72-GHz optical mm-wave by an RF signal of 9 GHz without any optical filtering is experimentally demonstrated. The radio-over-fiber system with 3.5-Gb/s OOK downstream link based on this generated 72-GHz mm-wave is also experimentally demonstrated. As we know, it is the first time to realize frequency eightfold mm-wave signal generation with simultaneous carrier suppression by using only one single-drive MZM in experiment. Auteurs: Huizhong Zhang;Lin Cai;Shuixian Xie;Kaiming Zhang;Xinxing Wu;Ze Dong; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 6 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Stator Structure for Active Axial Force Improvement in a One-Axis Actively Positioned Single-Drive Bearingless Motor
 Résumé:This paper presents a novel stator structure in an actively positioned bearingless motor with 1-degree of freedom. The single-drive bearingless motor concept has been adapted so that the torque and active axial force are regulated independently by the q- and d-axis currents, respectively, with only one three-phase inverter. The axial z-axis position is actively regulated, but the other axes (i.e., the radial and tilting movements) are passively stabilized. A novel stator structure has been proposed to enhance the active axial force. The stator is designed with soft magnetic composites. Experiments confirmed that the active axial force is enhanced by 50%. Auteurs: Hiroya Sugimoto;Itsuki Shimura;Akira Chiba; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4414 - 4421 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Symmetric Double-Slot Structure for Antipodal Vivaldi Antenna to Lower Cross-Polarization Level
 Résumé:An antipodal Vivaldi antenna (AVA) with novel symmetric two-layer double-slot structure is proposed. When excited with equiamplitude and opposite phase, the two slots will have the sum vector of their E-field vectors parallel to the antenna’s plane, which is uniform to the E-field vector in the slot of a balanced AVA with three-layer structure. Compared with a typical AVA with the same size, the proposed antenna has better impedance characteristics because of the amelioration introduced by the coupling between the two slots, as well as the more symmetric radiation patterns and the remarkably lowered cross-polarization level at the endfire direction. For validating the analysis, an UWB balun based on the double-sided parallel stripline is designed for realizing the excitation, and a sample of the proposed antenna is fabricated. The measured results reveal that the proposed has an operating frequency range from 2.8 to 15 GHz, in which the cross-polarization level is less than −24.8 dB. Besides, the group delay of two face-to-face samples has a variation less than 0.62 ns, which exhibits the ability of the novel structure for transferring pulse signal with high fidelity. The simple two-layer structure, together with the improvement both in impedance and radiation characteristics, makes the proposed antenna much desirable for the UWB applications. Auteurs: Ya-Wei Wang;Zhong-Wu Yu; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5599 - 5604 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel TD-VIE Based on MOT Scheme for Analysis of Dispersive Objects
 Résumé:A novel time-domain volume integral equation (TD-VIE) is proposed to analyze the transient electromagnetic scattering from inhomogeneous dispersive objects. In this TD-VIE method, the higher order Nyström method is applied in spatial domain. Namely, the curvilinear tetrahedron elements are utilized to discretize dielectric objects and resulting unknowns are volume electric current density. The Lagrange interpolation polynomials are used to represent spatial basis functions. In temporal domain, the marching-on-in-time (MOT) scheme is applied and the shifted Lagrange interpolation functions are used to represent temporal basis functions. Moreover, the point-matching method is applied both in spatial and temporal domain. Compared with the traditional spatial Schaubert–Wilton–Glisson basis based on TD-VIE, this novel TD-VIE method is more efficient. Several numerical examples have demonstrated that the proposed method is accurate, stable, and also more efficient than the traditional TD-VIE. Auteurs: Shifei Tao;Jun Cao;Zhenhong Fan;R. S. Chen; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5387 - 5395 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Thermomagnetic-Actuated Gripper With a Piezoelectric–Pyroelectric Sensing Readout of Gripping States and Forces
 Résumé:In this paper, we reported a thermomagnetic-actuated gripper with a piezoelectric–pyroelectric sensing readout of gripping states and forces. The gripper consists of two CuBe cantilever beams, a Gd sheet, NdFeB hard magnets, a thermoelectric generator (TEG), a piezoelectric–pyroelectric PZT sheet, and a polymer-polymethyl methacrylate base. When TEG cools the Gd sheet lower than its Curie temperature, the magnetic attraction between the Gd sheet and the NdFeB magnets is produced due to the thermomagnetic property of the Gd sheet. Subsequently, the magnetic attractive force deflects two beams until beams contact to each other. Thus, the gripper can grasp a small object. Furthermore, when the gripper is operated to grasp the object, the piezoelectric–pyroelectric PZT sheet of the gripper produces voltage response. Through analyzing the voltage response, the gripping state is detected and subsequently the gripping force is obtained. After gripping, a negative dc current is applied to TEG to heat the Gd sheet higher than Gd’s Curie temperature. Due to this, the magnetic attractive force is reduced and eventually eliminated. Consequently, the beams are separated due to their spring-back force. Thus, the gripper releases the object. The experimental results show that the gripper can be sequentially operated to grasp and release the object. Furthermore, as the current applied to the TEG is increased, the gripping force is increased. The maximum gripping force of the gripper is 0.69 N when a dc current of 0.7 A is applied. Moreover, when comparing conventional magnetic-field-actuated magnetic grippers, our gripper can be individually operated by applied currents, detect the gripping state, and sense the gripping force. Auteurs: Chin-Chung Chen;Tien-Kan Chung;Chu-Yi Lin; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 16 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Trail Detection and Scene Understanding Framework for a Quadrotor UAV With Monocular Vision
 Résumé:Vision-based trail detection and autonomous scene understanding play a key role for unmanned aerial vehicles (UAVs) working in complex outdoor environments such as isolated disaster sites. This paper investigates the problems associated with trail detection and tracking, as well as autonomous scene understanding using a quadrotor UAV. A framework that integrates support vector machine-based trail detection with a trail tracker is proposed to accomplish trail direction estimation and tracking at a low cost of computation and in real time. To accurately perform online parameter estimation, a performance test is designed and implemented to evaluate the accuracy. Moreover, the simple linear iterative clustering superpixel segmentation algorithm is utilized in the proposed system framework to guarantee the scene segmentation accuracy. Visual detection for significant objects or people is implemented by using single shot multibox detector algorithm. A series of experiments are conducted by using a quadrotor platform DJI M100 and experimental results show the validity and practicality of the proposed approach. Auteurs: Yisha Liu;Qunxiang Wang;Yan Zhuang;Huosheng Hu; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6778 - 6787 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Tri-Band Wilkinson Power Divider for Multiband Wireless Applications
 Résumé:This letter presents a novel and simple technique for the design of an arbitrary tri-band Wilkinson power divider. The proposed technique is based on the use of quarter-wave open stubs (QWOS) at the desired operation frequencies, placed at appropriate positions along the divider’s 50- $\Omega$ output transmission lines, to create the targeted tri-band response. These stubs present a high impedance at the frequencies of interest, while introducing transmission zeroes between the operation bands. For a compact design, slow-wave structure has been adopted to miniaturize the conventional divider’s arms. To validate the above concept, a power divider—intended to operate in the 1.5-, 1.9-, and 2.35-GHz frequency bands—is designed. The results of the fabricated circuit present low insertion loss of less than 0.45 dB while offering an isolation better than 15 dB in the three bands of operation. Compared to recently published results, the proposed divider exhibits the largest fractional bandwidth at each operation frequency. Furthermore, it can be easily extended to more bands by adding QWOS depending on the required number of bands. Auteurs: Basem M. Abdelrahman;Hesham N. Ahmed;A. I. Nashed; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 891 - 893 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Utilization of Image Registration Techniques to Process Mastcam Images in Mars Rover With Applications to Image Fusion, Pixel Clustering, and Anomaly Detection
 Résumé:The Mars Science Laboratory is a robotic rover mission to Mars launched by NASA on November 26, 2011, which successfully landed the Curiosity rover in Gale Crater on August 6, 2012. The Curiosity rover has two mast cameras (Mastcams) that acquire stereo images at a number of different wavelengths. Each camera has nine bands of which six bands are overlapped in the two cameras. These acquired stereo band images at different wavelengths can be fused into a 12-band multispectral image cube, which could be helpful to guide the rover to interesting locations. Since the two Mastcams’ fields of view are three times different from each other, in order to fuse the left- and right-camera band images to form a multispectral image cube, there is a need for a precise image alignment of the stereo images with registration errors at the subpixel level. A two-step image alignment approach with a novel utilization of existing image registration algorithms is introduced in this paper and is applied to a set of Mastcam stereo images. The effect of the two-step alignment approach using more than 100 pairs of Mastcam images, selected from over 500000 images in NASA's Planetary Data System database, clearly demonstrated that the fused images can improve pixel clustering and anomaly detection performance. In particular, registration errors in the subpixel level are observed with the applied alignment approach. Moreover, the pixel clustering and anomaly detection performance have been observed to be better when using fused images. Auteurs: Bulent Ayhan;Minh Dao;Chiman Kwan;Hua-Mei Chen;James F. Bell;Richard Kidd; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4553 - 4564 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Variable Flux Memory Machine With Series Hybrid Magnets
 Résumé:This paper proposes a novel variable flux memory (VFM) machine, in which the “constant” permanent magnet (CPM) with high coercive force and the “variable” PM (VPM) with low coercive force are alternatively located in the interior-PM rotor. Thus, the VPMs and CPMs are magnetically connected in series, with which the CPMs can assist the VPMs to withstand the unintentional demagnetization caused by armature reaction. Therefore, a high armature current can be applied to the machine. Meanwhile, the reluctance torque is retrieved. Thus, a high torque density can be obtained. Based on two-dimensional finite element analysis, first, the electromagnetic performance of the proposed VFM machine in two extreme magnetization states is evaluated in detail. Then, the demagnetization and remagnetization characteristics are investigated, in which the working points of VPMs are illustrated. Furthermore, the advantages of improved efficiency of the proposed VFM machine are demonstrated. A prototype machine is manufactured and tested to validate the predictions. Auteurs: Hao Hua;Z. Q. Zhu;Adam Pride;Rajesh P. Deodhar;Toshinori Sasaki; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4396 - 4405 Editeur: IEEE Document complet vers site de l'éditeur
» A Numerical Approach to Stability of Multiclass Queueing Networks
 Résumé:The multiclass queueing network (McQN) arises as a natural multiclass extension of the traditional (single-class) Jackson network. In a single-class network, subcriticality (i.e., subunitary nominal workload at every station) entails stability, but this is no longer sufficient when jobs/customers of different classes (i.e., with different service requirements and/or routing scheme) visit the same server; therefore, analytical conditions for stability of McQNs are lacking, in general. In this note, we design a numerical (simulation-based) method for determining the stability region of a McQN, in terms of arrival rate(s). Our method exploits certain (stochastic) monotonicity properties enjoyed by the associated Markovian queue-configuration process. Stochastic monotonicity is a quite common feature of queueing models and can be easily established in the single-class framework (Jackson networks); recently, also for a wide class of McQNs, including first-come-first-serve networks, monotonicity properties have been established. Here, we provide a minimal set of conditions, under which the method performs correctly. Eventually, we illustrate the use of our numerical method by presenting a set of numerical experiments, covering both single- and multiclass networks. Auteurs: Haralambie Leahu;Michel Mandjes;Ana-Maria Oprescu; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5478 - 5484 Editeur: IEEE Document complet vers site de l'éditeur
» A Parametric Model Approach for Structural Reconstruction of Scale-Free Networks
 Résumé:We propose a parametric network generation model which we call network reconstruction model (NRM) for structural reconstruction of scale-free real networks with power-law exponent greater than 2 in the tail of its degree distribution. The reconstruction method for a real network is concerned with finding the optimal values of the model parameters by utilizing the power-law exponents of model network and the real network. The method is validated for certain real world networks. The usefulness of NRM in order to solve structural reconstruction problem is demonstrated by comparing its performance with some existing popular network generative models. We show that NRM can generate networks which follow edge-densification and densification power-law when the model parameters satisfy an inequality. Computable expressions of the expected number of triangles and expected diameter are obtained for model networks generated by NRM. Finally, we numerically establish that NRM can generate networks with shrinking diameter and modular structure when specific model parameters are chosen. Auteurs: Pradumn Kumar Pandey;Bibhas Adhikari; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2072 - 2085 Editeur: IEEE Document complet vers site de l'éditeur
» A Participatory Urban Traffic Monitoring System: The Power of Bus Riders
 Résumé:This paper presents a participatory sensing-based urban traffic monitoring system. Different from existing works that heavily rely on intrusive sensing or full cooperation from probe vehicles, our system exploits the power of participatory sensing and crowdsources the traffic sensing tasks to bus riders’ mobile phones. The bus riders are information source providers and, meanwhile, major consumers of the final traffic output. The system takes public buses as dummy probes to detect road traffic conditions, and collects the minimum set of cellular data together with some lightweight sensing hints from the bus riders’ mobile phones. Based on the crowdsourced data from participants, the system recovers the bus travel information and further derives the instant traffic conditions of roads covered by bus routes. The real-world experiments with a prototype implementation demonstrate the feasibility of our system, which achieves accurate and fine-grained traffic estimation with modest sensing and computation overhead at the crowd. Auteurs: Zhidan Liu;Shiqi Jiang;Pengfei Zhou;Mo Li; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2851 - 2864 Editeur: IEEE Document complet vers site de l'éditeur
» A Physical Surface Roughness Model and Its Applications
 Résumé:This paper covers the essential aspects of modeling surface roughness for microwave applications based on underlying physics. After a short summary of the relevant field theoretical fundamentals, surface roughness metrology and commonly used roughness parameters are described. Existing models and their limitations are discussed before the recently proposed Gradient Model is introduced. To this purpose, the modeling approach, the derivation from Maxwell’s equations, model predictions, and their experimental verification are shown. Reasonable choices for effective material parameters reflecting the electromagnetic effects of surface roughness as well as a corresponding surface impedance concept are derived. Both concepts allow for easy application of the Gradient Model with 3-D field solvers or analytical models. The obtained simulation results illustrate roughness impact on loss and phase delay in typical transmission lines. Comparison to measurement results up to 100 GHz shows that the Gradient Model accurately predicts these quantities for rough conductor surfaces. As it is not limited to transmission lines only, it significantly improves the design process for arbitrary microwave applications with 3-D field solvers for this frequency range. Auteurs: Gerald Gold;Klaus Helmreich; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3720 - 3732 Editeur: IEEE Document complet vers site de l'éditeur
» A Post-Swirl Maneuvering Propulsor Application to Undersea Vehicles
 Résumé:A method to generate vehicle maneuvering forces from a propulsor alone has been applied to a generic undersea vehicle. Open and ducted post-swirl propulsors were configured with an upstream rotor and downstream stator row. During normal operation, the downstream stator blades are all situated at the same pitch angle and generate a roll moment to counter the torque produced by the rotor. By varying the pitch angles of the stator blade about the circumference, it is possible to generate a mean stator side force that can be used to maneuver the vehicle. In addition, the side force can be increased with increasing thrust producing side forces at very low vehicle velocities enabling low-speed maneuvering capability. The viscous, 3-D Reynolds-averaged Navier–Stokes (RANS) commercial code Fluent was used to predict the vehicle and propulsor component forces as well as the velocity field. Open and ducted geometric configurations were studied and force coefficients computed and compared with currently used control surface forces. Computations predicted that the maneuvering propulsor generated side forces equivalent to those produced by conventional control surfaces with side force coefficients on the order of 0.25 for the open propulsor at the self-propulsion point. This translates to 50% larger forces than can be generated by conventional control surfaces on 21$^{\prime \prime}$ unmanned undersea vehicles. The ducted configuration produces maximum side force coefficients on the order of 0.15, which is still sufficient for vehicle control. Both configurations produced side forces for the Bollard pull condition indicating low-speed maneuvering capability. Auteurs: Stephen A. Huyer; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 770 - 781 Editeur: IEEE Document complet vers site de l'éditeur
» A Power-Packed Issue
 Résumé:Welcome to the power and energy theme issue of IEEE Potentials. The following four articles will address highimpact topics in the world of power systems, written by energy experts from both industry and academia. I hope you enjoy reading them and gain a greater insight into this exciting field. Auteurs: Edvina Uzunovic;Juan Carlos Montero Quiros; Apparue dans: IEEE Potentials Date publication: 10.-2017, volume: 36, issue:5, pages: 6 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» A Preventive Approach for Solving Battery Imbalance Issue by Using a Bidirectional Multiple-Input Ćuk Converter Working in DCVM
 Résumé:State of charge (SoC) imbalance among batteries in a battery energy storage system (BESS) degrades the system performance and may lead to safety issue. A bidirectional multiple-input Ćuk converter for the BESS is proposed to prevent batteries from SoC imbalance issue. Compared to the traditional BESS, the battery balancing and voltage/current regulation subsystems are combined into one. As a result, the overall system complexity is significantly reduced. Moreover, the current flow of each battery is self-adjusted according to its terminal voltage. Therefore, the system does not require sophisticated control algorithm for battery balancing. Moreover, the proposed system has no energy dumping and energy transferring between batteries, which avoids unnecessary energy lose. Due to the nature of multiple-input converter structure, the proposed system can handle certain component failure. The proposed approach of designing the BESS has been investigated through simulation and validated experimentally. Auteurs: Jian Qi;Dylan Dah-Chuan Lu; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7780 - 7789 Editeur: IEEE Document complet vers site de l'éditeur
» A Prototype Therapy System for Transcutaneous Application of Boiling Histotripsy
 Résumé:Boiling histotripsy (BH) is a method of focused ultrasound surgery that noninvasively applies millisecond-length pulses with high-amplitude shock fronts to generate liquefied lesions in tissue. Such a technique requires unique outputs compared to a focused ultrasound thermal therapy apparatus, particularly to achieve high in situ pressure levels through intervening tissue. This paper describes the design and characterization of a system capable of producing the necessary pressure to transcutaneously administer BH therapy through clinically relevant overlying tissue paths using pulses with duration up to 10 ms. A high-voltage electronic pulser was constructed to drive a 1-MHz focused ultrasound transducer to produce shock waves with amplitude capable of generating boiling within the pulse duration in tissue. The system output was characterized by numerical modeling with the 3-D Westervelt equation using boundary conditions established by acoustic holography measurements of the source field. Such simulations were found to be in agreement with directly measured focal waveforms. An existing derating method for nonlinear therapeutic fields was used to estimate in situ pressure levels at different tissue depths. The system was tested in ex vivo bovine liver samples to create BH lesions at depths up to 7 cm. Lesions were also created through excised porcine body wall (skin, adipose, and muscle) with 3–5 cm thickness. These results indicate that the system is capable of producing the necessary output for transcutaneous ablation with BH. Auteurs: Adam D. Maxwell;Petr V. Yuldashev;Wayne Kreider;Tatiana D. Khokhlova;George R. Schade;Timothy L. Hall;Oleg A. Sapozhnikov;Michael R. Bailey;Vera A. Khokhlova; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 10.-2017, volume: 64, issue:10, pages: 1542 - 1557 Editeur: IEEE Document complet vers site de l'éditeur
» A pyrrhic victory for nuclear power [News]
 Résumé:By late this year or early in 2018, two nuclear reactors could start operating in China-an event that might be a lifesaver for the units' crippled builder and designer, Westinghouse Electric Co., and for the technology they represent. Both Westinghouse and its prized AP1000 reactor design have suffered a series of humbling setbacks this year. The AP1000 is arguably the world's most advanced commercial reactor. It is designed to passively cool itself during an accidental shutdown, theoretically avoiding accidents like those at Ukraine's Chernobyl power plant and Japan's Fukushima Daiichi. And for over a decade, it has been the presumed successor to China's mainstay reactors, which employ a 1970s-era French design. Auteurs: Peter Fairley; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 11 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» A Q-Band Low-Profile Dual Circularly Polarized Array Antenna Incorporating Linearly Polarized Substrate Integrated Waveguide-Fed Patch Subarrays
 Résumé:An integrated low-profile dual circularly polarized (dual CP) array antenna operating in the Q-band is proposed in this paper, which is realized by sequentially rotating subarrays comprised linearly polarized (LP) substrate integrated waveguide (SIW)-fed patches. The design methodology and working mechanism of the LP SIW-fed patches is presented first, which is implemented with a two-layer printed circuit board structure where the SIW feeding network is located in the bottom substrate and the patches are on the top substrate. Four subarrays are then arranged according to the requirements of a sequential rotation array for producing CP directive beams. A two-layer SIW feeding network for providing the required amplitude and phase distributions for the four subarrays is designed, which includes two input ports for exciting CP radiation with opposite handedness, respectively. Prototypes of the LP subarray and the integrated dual CP array antenna were fabricated and measured. Good agreement between the simulation and measured results validates the designs. The proposed low-cost and lightweight dual CP antenna owns the advantages of wide useful bandwidth (8.9%), high isolation of more than 19 dB, low profile of less than $0.1\lambda _{0}$ , and good orthogonal polarization discrimination higher than 25 dB. Auteurs: Jun Xu;Wei Hong;Zhi Hao Jiang;Jixin Chen;Hui Zhang; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5200 - 5210 Editeur: IEEE Document complet vers site de l'éditeur
» A Q-Slot Monopole for UWB Body-Centric Wireless Communications
 Résumé:This paper presents a novel and simple ultrawideband printed rectangular monopole antenna for body-centric wireless communications. The design is based on etching a Q-slot on a rectangular radiator and is optimized to produce the largest bandwidth in free space and close to the human body. We analyze the design of the proposed antenna and assess its performance in terms of bandwidth, gain, efficiency, and radiation patterns. We also characterize the antenna in the time-domain by calculating its fidelity factor. Our results show that the Q-slot antenna maintains its bandwidth when placed in close contact with the human body, or in contact with breast-mimicking tissue phantoms. The very good agreement between the calculated and measured antenna performances in free space and on body suggests that the antenna is immune to variations in the human tissue and is also robust to fabrication tolerances. Auteurs: Bright Yeboah-Akowuah;Panagiotis Kosmas;Yifan Chen; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5069 - 5075 Editeur: IEEE Document complet vers site de l'éditeur
» A Quasi-Resonant Switched-Capacitor Multilevel Inverter With Self-Voltage Balancing for Single-Phase High-Frequency AC Microgrids
 Résumé:In this paper, a quasi-resonant switched-capacitor (QRSC) multilevel inverter (MLI) is proposed with self-voltage balancing for single-phase high-frequency ac (HFAC) microgrids. It is composed of a QRSC circuit (QRSCC) in the frontend and an H-bridge circuit in the backend. The input voltage is divided averagely by the series-connected capacitors in QRSCC, and any voltage level can be obtained by increasing the capacitor number. The different operational mechanism and the resulting different application make up for the deficiency of the existing switched-capacitor topologies. The capacitors are connected in parallel partially or wholly when discharging to the load, thus the self-voltage balancing is realized without any high-frequency balancing algorithm. In other words, the proposed QRSC MLI is especially adapted for HFAC fields, where fundamental frequency modulation is preferred when considering the switching frequency and the resulting loss. The quasi-resonance technique is utilized to suppress the current spikes that emerge from the instantaneous parallel connection of the series-connected capacitors and the input source, decreasing the capacitance, increasing their lifetimes, and reducing the electromagnetic interference, simultaneously. The circuit analysis, power loss analysis, and comparisons with typical switched-capacitor topologies are presented. To evaluate the superior performances, a nine-level prototype is designed and implemented in both simulation and experiment, whose results confirm the feasibility of the proposed QRSC MLI. Auteurs: Jun Zeng;Jialei Wu;Junfeng Liu;Huafang Guo; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2669 - 2679 Editeur: IEEE Document complet vers site de l'éditeur
» A Randomized Approach to Probabilistic Footprint Estimation of a Space Debris Uncontrolled Reentry
 Résumé:This paper studies the problem of characterizing the region of the airspace that will be occupied by a space debris during an uncontrolled reentry (footprint), with the final goal of supporting the air traffic controllers in their task of guiding aircraft safely from their origin to their destination. Given the various sources of uncertainty affecting the debris dynamics, the reentry process is characterized probabilistically and the problem of determining the footprint is formulated in terms of a chance-constrained optimization program, which is solved via a simulation-based method. When observations of the debris initial position and radar measurements of the aircraft prior to the reentry event are available, nonlinear filtering techniques can be adopted and the posterior probability distribution of the debris position as well as of the wind field affecting the reentry process can be integrated in the chance-constraint formulation so as to obtain an enhanced estimate of the footprint. Simulation results show the efficacy of the approach. Auteurs: Alessandro Falsone;Maria Prandini; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2657 - 2666 Editeur: IEEE Document complet vers site de l'éditeur
» A Resonant ZVZCS DC–DC Converter With Two Uneven Transformers for an MVDC Collection System of Offshore Wind Farms
 Résumé:A resonant zero-voltage and zero-current-switching (ZVZCS) dc-dc converter is proposed in this paper for a medium-voltage dc collection system of offshore wind farms. The resonant converter is composed of two full-bridge cells sharing a bridge leg, two transformers with uneven power ratings and different functions, whose secondary windings are connected in series and a voltage-doubler rectifier. The converter operates in discontinuous current mode and can achieve zero-current switching for four main power switches and rectifier diodes over the whole load range. The two auxiliary switches with small forward current can be turned on with ZVZCS, and turned off with zero-voltage switching. Hence, the switching loss can be reduced and efficiency is improved. The operation principle of the converter is analyzed and design rules of main parameters are presented. The influences of the turn ratios of auxiliary transformer and resonant capacitance on the peak and switching-off currents are discussed in detail. Furthermore, a model is built in PLECS and simulation results are given. A 150-1500 V/2 kW prototype is established and tested to verify the operation principle and design rules. Auteurs: Liangcai Shu;Wu Chen;Guangfu Ning;Wu Cao;Jun Mei;Jianfeng Zhao;Chun Liu;Guoqing He; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7886 - 7895 Editeur: IEEE Document complet vers site de l'éditeur
» A Resource-Limited Hardware Accelerator for Convolutional Neural Networks in Embedded Vision Applications
 Résumé:In this brief, we introduce an architecture for accelerating convolution stages in convolutional neural networks (CNNs) implemented in embedded vision systems. The purpose of the architecture is to exploit the inherent parallelism in CNNs to reduce the required bandwidth, resource usage, and power consumption of highly computationally complex convolution operations as required by real-time embedded applications. We also implement the proposed architecture using fixed-point arithmetic on a ZC706 evaluation board that features a Xilinx Zynq-7000 system on-chip, where the embedded ARM processor with high clocking speed is used as the main controller to increase the flexibility and speed. The proposed architecture runs under a frequency of 150 MHz, which leads to 19.2 Giga multiply accumulation operations per second while consuming less than 10 W in power. This is done using only 391 DSP48 modules, which shows significant utilization improvement compared to the state-of-the-art architectures. Auteurs: Shayan Moini;Bijan Alizadeh;Mohammad Emad;Reza Ebrahimpour; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1217 - 1221 Editeur: IEEE Document complet vers site de l'éditeur
» A Review of On-Chip Micro Supercapacitors for Integrated Self-Powering Systems
 Résumé:Miniaturized self-powering systems that integrate both energy harvesters and energy storage units as the power sources are essential to realize maintenance-free wireless sensor networks, implantable medical devices, and active radio frequency identification systems. On-chip micro supercapacitors (MSCs) are promising candidates for energy storage in such systems by providing high power densities, fast charge/discharge rates, and long cycle life. Researchers have been improving the performances, especially energy and power densities, of MSCs in recent years. This paper reviews the fundamental working mechanisms and design considerations of on-chip MSCs with special emphasis on the advantages of 3-D configurations. Typical fabrication methods are summarized, and their effects on the device performance and system integration are analyzed. In particular, the power generation of micro energy harvesters and the power consumption of typical wireless micro systems are surveyed, providing the basic and targeting performance requirements of future MSCs that can be integrated with them. [2017-0069] Auteurs: Caiwei Shen;Sixing Xu;Yingxi Xie;Mohan Sanghadasa;Xiaohong Wang;Liwei Lin; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 949 - 965 Editeur: IEEE Document complet vers site de l'éditeur
» A Robust Active Damping Control Strategy for an $LCL$ -Based Grid-Connected DG Unit
 Résumé:The connection of a distributed generation (DG) unit to a weak power system is challenging due to stability issues resulted from dynamic interactions between the DG unit and the grid. An LCL-based DG unit is a particularly challenging case due to the presence of a high resonant peak in its frequency response. This paper proposes a robust control strategy to overcome the stability issues of an LCL-based DG unit connected to a weak grid. The main advantage of the proposed control strategy is that it guarantees stability and satisfactory transient performance against the variations of grid impedance. Moreover, it is able to decouple the d and q channels of the control system, which enables independent regulation of the real and reactive output power of the DG unit. Real-time simulations and experimental tests illustrate the effectiveness of the proposed controller in terms of improved transient performance, robust stability, and satisfactory controller set-point tracking. Auteurs: Mahdieh S. Sadabadi;Aboutaleb Haddadi;Houshang Karimi;Alireza Karimi; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8055 - 8065 Editeur: IEEE Document complet vers site de l'éditeur
» A Robust Detection Method of Control Points for Calibration and Measurement With Defocused Images
 Résumé:This paper presents a detection method of control points for the camera calibration and measurement applications, which is robust to defocus. Our method is based on a ground truth, which we call ridge invariance. That is, the positions of broad-brush lines’ ridge lines are invariant to defocus blur. First, the ridge invariance is deduced in theory. Then, the methods for ridge point’s detection including defocus degree estimation and salience enhancement are deduced. In calibration and measurement experiments, new marks are designed and control points are determined at intersects of the ridge curves. Experiments show that our method can obtain precise calibration and measurement results with images in a large defocus amount range. In the effective defocus amount range, the accuracy of the proposed method almost keeps unchanged to the best values. The proposed method has approximated the same performance as conventional methods at good focus values. Auteurs: Wendong Ding;Xilong Liu;De Xu;Dapeng Zhang;Zhengtao Zhang; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2725 - 2735 Editeur: IEEE Document complet vers site de l'éditeur
» A Robust Event-Triggered Approach for Fast Sampled-Data Extremization and Learning
 Résumé:This paper presents a general framework for the analysis and design of a class of model-free, robust, and efficient sampled-data-based algorithms for extremization and learning in continuous-time nonlinear systems that generate response maps with an optimal operational set. In particular, we consider plants described by differential inclusions, interconnected in a sampled-data setting with a robust learning algorithm characterized by a constrained difference inclusion. In contrast to standard sampled-data-based approaches, where the learning dynamics are updated after a fixed sufficiently long sampling time has passed, we design a robust dynamic event-based mechanism that triggers the control action as soon as the rate of change of the output of the plant is sufficiently small. By using this event-based update rule, a significant improvement in the convergence time of the closed-loop system can be achieved. Using the framework of set-valued hybrid dynamical systems, we establish for the closed-loop system the existence of a uniformly asymptotically stable compact set, which, by an appropriate tuning of the control parameters, can be made arbitrarily close to the optimal operational set. Our results generalize existing results for periodic sampled-data extremum seeking, and can be used to solve model-free multivariable smooth/nonsmooth constrained optimization problems, as well as learning problems in game theoretical scenarios. Auteurs: Jorge I. Poveda;Andrew R. Teel; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 4949 - 4964 Editeur: IEEE Document complet vers site de l'éditeur
» A Robust Flywheel Energy Storage System Discharge Strategy for Wide Speed Range Operation
 Résumé:Wide speed range operation in discharge mode is essential for ensuring discharge depth and energy storage capacity of a flywheel energy storage system (FESS). However, for a permanent magnet synchronous motor/generator-based FESS, the wide-range speed variation in a short discharge period causes consecutive decreases in ac voltage frequency and amplitude. As a result, operation point shift leads to performance deterioration of the conventional local linearization based dc-link voltage control strategies. This study aims to realize a consistent robust discharge performance within the entire available operation range for FESS. We propose a robust discharge strategy that incorporates the speed variation to the dc-link voltage controller. A speed-dependent extended state observer is designed to realize global linearization and enhance the robustness. A speed adaptive feedback control law is designed to ensure consistent dynamic performance within the entire available operation range. Finally, the discharge strategy is validated at different speeds on a high-speed FESS test bench. Auteurs: Xiang Zhang;Jiaqiang Yang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7862 - 7873 Editeur: IEEE Document complet vers site de l'éditeur
» A Robust Translational Motion Compensation Method for ISAR Imaging Based on Keystone Transform and Fractional Fourier Transform Under Low SNR Environment
 Résumé:In this work, a parametric-based approach is proposed to perform joint range alignment and phase adjustment based on the intention of fully exploiting the energy of all the scatterers in the moving target and the two-dimensional coherent accumulation gain of both range and azimuth compressions. To that end, first, translational motion is modeled as a polynomial signal, and inspired by the fact that all the scatterers in the moving target experience the same translational range history, the phase difference operation and keystone transform (KT) are utilized to transform the energy of all the scatterers into one range cell. Second, by the virtue of the fractional Fourier transform (FrFT), the energy of all the scatterers is coherently accumulated into a peak point, and from which the polynomial coefficients can be obtained accurately. With the estimated polynomial coefficients, the dechirp operation and KT are applied jointly to compensate range misalignment and phase error. The analysis of the proposed method shows that it is of low computational complexity due to avoiding multidimensional search and improves the output SNR providing satisfactory low SNR performance. The experimental results are provided to demonstrate the performance of the proposed method compared with the state-of-the-art algorithms. Auteurs: Dong Li;Muyang Zhan;Hongqing Liu;Yong Liao;Guisheng Liao; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2140 - 2156 Editeur: IEEE Document complet vers site de l'éditeur
» A Seaglider-Integrated Digital Monitor for Bioacoustic Sensing
 Résumé:An acoustic Digital MONitor (DMON) has been integrated into a Seaglider autonomous underwater vehicle to serve as a general-use tool for passive acoustic sensing of marine mammal vocalizations. The system is being developed as a complement to conventional ship-based cetacean survey methods. The acoustic system includes three omnidirectional hydrophones, one located on centerline of the aft payload hatch and one on each wingtip. An onboard real-time detector has been implemented to record an audio sample if ambient noise has risen above a user-prescribed signal-to-noise ratio (SNR) threshold level. The data size and the number of detections are available in semi-real time, and the acoustic data are retrieved upon recovery of the instrument. Because the DMON system interfaces with the Seaglider firmware, the glider pilot has the capability to modify several operational parameters governing the collection of acoustic data while the glider is deployed to tailor the data recording to the desired mission objectives. This implementation is referred to as the Seaglider Customizable Sampling Configuration (SCSC) DMON and has recorded a wide variety of cetacean vocal activity offshore the Hawaiian Islands. Auteurs: Lora J. Van Uffelen;Ethan H Roth;Bruce M. Howe;Erin M. Oleson;Yvonne Barkley; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 800 - 807 Editeur: IEEE Document complet vers site de l'éditeur
» A Self-Adaptive Capacitive Compensation Technique for Body Channel Communication
 Résumé:In wireless body area network, capacitive-coupling body channel communication (CC-BCC) has the potential to attain better energy efficiency over conventional wireless communication schemes. The CC-BCC scheme utilizes the human body as the forward signal transmission medium, reducing the path loss in wireless body-centric communications. However, the backward path is formed by the coupling capacitance between the ground electrodes (GEs) of transmitter (Tx) and receiver (Rx), which increases the path loss and results in a body posture dependent backward impedance. Conventional methods use a fixed inductor to resonate with the backward capacitor to compensate the path loss, while it's not effective in compensating the variable backward impedance induced by the body movements. In this paper, we propose a self-adaptive capacitive compensation (SACC) technique to address such a problem. A backward distance detector is introduced to estimate the distance between two GEs of Tx and Rx, and a backward capacitance model is built to calculate the backward capacitance. The calculated backward capacitance at varying body posture is compensated by a digitally controlled tunable inductor (DCTI). The proposed SACC technique is validated by a prototype CC-BCC system, and measurements are taken on human subjects. The measurement results show that 9dB–16 dB channel enhancement can be achieved at a backward path distance of 1 cm-10 cm. Auteurs: Jingna Mao;Huazhong Yang;Yong Lian;Bo Zhao; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1001 - 1012 Editeur: IEEE Document complet vers site de l'éditeur
» A Self-Calibrated Cryogenic Current Cell for 4.2 K Current Steering D/A Converters
 Résumé:This brief presents a cryogenic CMOS unit current cell operating from room temperature down to 4.2 K, and it is primarily designed for low temperature current steering (CS) D/A converters (DACs). A novel structure along with an analog calibration technique is proposed in designing the cell that helps it to overcome low temperature induced nonlinear and mismatch effects. Due to the flexible configuration of the cell architecture, it can be used in both LSB and MSB parts of a partially-segmented CS DAC. The current cell retains its 4-bit precision level from 300 K down to 4.2 K, and drives a $50~\Omega$ load to 6.8 mV in 600 ps rise time. A 6-bit converter utilizing the cell achieves differential and integral nonlinearity of 0.17 LSB and 0.33 LSB, respectively, while its average power consumption is <3.2 mW from a 3 V power supply. It is fabricated using a commercial 0.5 $\mu \text{m}$ single poly three metal silicon-on-sapphire CMOS process. Auteurs: Md Tanvir Rahman;Torsten Lehmann; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1152 - 1156 Editeur: IEEE Document complet vers site de l'éditeur
» A Semianalytical Matching Approach for Power Amplifier With Extended Chebyshev Function and Real Frequency Technique
 Résumé:In this paper, an extended Chebyshev function is proposed to adapt the matching condition of the power amplifier (PA) by introducing a new factor. A set of impedance functions can be directly calculated along with the variation of a new variable, and the first element extracted from the functions is distributed in a wide range. In addition, the impedance function whose first element is the closest to the output capacitance of the transistor can be easily read out and selected as the original matching network. The fundamental impedance of the selected function will be reached a good matching state, and the impedances out of band will be on the edge of Smith chart. To achieve better performances, the real frequency technique is applied to adjust the harmonic impedances preventing it from falling into the low-efficiency region. Two PAs with a relative bandwidth of 34% and 75% are implemented to validate the proposed approach. Auteurs: Zhijiang Dai;Songbai He;Jun Peng;Chaoyi Huang;Weimin Shi;Jingzhou Pang; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3892 - 3902 Editeur: IEEE Document complet vers site de l'éditeur
» A Separation Principle for Underactuated Lossless Lagrangian Systems
 Résumé:We study under-actuated Lagrangian systems without dissipative forces, augmented by a chain of integrators. For such systems, we solve the open problem of global tracking control via position measurements only; strictly speaking, we establish uniform global asymptotic stability for the closed loop system. As a corollary, we obtain an original statement for flexible-joint robots, which closes a long-standing open problem of output feedback nonlinear control. Auteurs: Sofia Avila-Becerril;Antonio Loría;Elena Panteley; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5318 - 5323 Editeur: IEEE Document complet vers site de l'éditeur
» A Sequential Decomposition Framework and Method for Calibrating Dynamic Origin—Destination Demand in a Congested Network
 Résumé:This paper presents a two-stage model to calibrate the time-dependent, dynamic origin-destination (O–D) demand under congested traffic conditions. The first-stage model estimates O–D trip rates by minimizing link demand deviation with a one-norm formulation approach, so that over the calibration time period, the traffic demand on calibration links matches with the link demand from the field data. Due to its linear model structure, the first-stage model is more computationally effective and solvable on large real-life networks compared with the commonly seen least-square formulation. Then, a time-dependent user equilibrium traffic assignment model is formulated at the second stage to adjust the departure time profile iteratively, aiming to match the calibrated result with the field observed dynamic traffic condition, i.e., time-dependent speed profile. The second-stage model starts from the concept of a demand–capacity–volume relationship at a congested road segment, where demand exceeds supply, and utilizes shockwave theory to capture the differences between true demand and volume output, together with the idea of using travel time propagation between origin and bottleneck locations to infer real demand at the origin location. The two-stage model was implemented and tested in a case study in Tucson, AZ, USA, as an experimental proof of concept, which demonstrated the effectiveness of the proposed calibration framework and method under circumstances, in which the departure time profile was systematically distorted and initial demand solutions deviated from the true O–D matrices. Auteurs: Xianbiao Hu;Yi-Chang Chiu;Jorge A. Villalobos;Eric Nava; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2790 - 2797 Editeur: IEEE Document complet vers site de l'éditeur
» A SiC CMOS Digitally Controlled PWM Generator for High-Temperature Applications
 Résumé:This paper describes a silicon carbide pulse width modulation (PWM) signal generator in the 1.2 μm HiT-SiC CMOS process developed by Raytheon Systems Ltd. The design features a 6-b binary input, which allows for setting a system's duty cycle. The results presented in this paper utilize a field programmable gate array board in the test setup to dynamically set the duty cycle by controlling each bit. A control current is also available to give the user added flexibility for tuning the duty cycle. Experimental results show the duty cycle range of the PWM generator to be between 4.7% and 95.2% at 400°C. Sustained operation of the circuit is demonstrated over a period of 50 h at 300°C. Finally, the PWM generator is evaluated in the operation of a boost converter. Auteurs: Sajib Roy;Robert C. Murphree;Affan Abbasi;Ashfaqur Rahman;Shamim Ahmed;James Austin Gattis;A. Matt Francis;Jim Holmes;H. Alan Mantooth;Jia Di; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8364 - 8372 Editeur: IEEE Document complet vers site de l'éditeur
» A SiC Power MOSFET Loss Model Suitable for High-Frequency Applications
 Résumé:The reduced chip size and unipolar current conduction mechanism make silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) suitable for high-frequency power electronics applications. Modeling the switching process of the SiC power MOSFET with parasitic components is important for achieving higher efficiency and power density system design. Therefore, this paper proposes a new concise yet accurate switching loss model for SiC power MOSFETs. Addressing the limitations in experimental measurements, numerical simulations are conducted to validate the proposed model taking the output capacitance Coss discharge and charge into consideration. The role of the parasitic components in the second-order model is discussed in depth for switching losses. Furthermore, this paper also provides guidelines in designing the gate driver for ultrafast SiC power MOSFETs. Auteurs: Xuan Li;Junning Jiang;Alex Q. Huang;Suxuan Guo;Xiaochuan Deng;Bo Zhang;Xu She; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8268 - 8276 Editeur: IEEE Document complet vers site de l'éditeur
» A Simple Harmonic Reduction Method in Multipulse Rectifier Using Passive Devices
 Résumé:This paper proposes a novel and passive harmonic reduction method at dc link of multipulse rectifier (MPR). The proposed method uses a single-phase diode-bridge rectifier to generate circulating current, which can shape the input line current of MPR. The input side of the single-phase diode-bridge rectifier is connected with the secondary winding of interphase reactor (IPR), and its output side is connected with load, which can recycle the harmonic energy and feed to load. The operation mode of the single-phase diode-bridge rectifier is analyzed, and the turn ratio of the IPR is designed optimally. Under ideal condition, the proposed MPR operates as a 24-pulse rectifier, and its total harmonic distortion (THD) of input line current is about 7.6%. Most of all, the proposed method is easy to be used in different 12-pulse rectifier topologies, and its conduction losses are far less than that of the conventional double-tapped IPR. Simulation and experiment results show that the THD of input line current is less than 5%. Auteurs: Fangang Meng;Xiaona Xu;Lei Gao; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2680 - 2692 Editeur: IEEE Document complet vers site de l'éditeur
» A Simplified Branch and Bound Approach for Model Predictive Control of Multilevel Cascaded H-Bridge STATCOM
 Résumé:Applying model predictive control (MPC) to cascaded H-bridge multilevel converters, while improving the dynamic performance, suffers from high computation burden due to substantial voltage vectors and switching combinations. In this paper, a simplified branch and bound approach is proposed to reduce the computation of the MPC for a cascaded H-bridge Static Synchronous Compensator (STATCOM). The underlying optimization problem of the current predictive control is a two-variable integer quadratic programming problem. With the proposed approach, the global optimal voltage vector can be selected within linear time instead of polynomial time. This is achieved by selecting the possible values of one variable as the branch, and enumerating the optimal integer results of each branch. The execution time of the proposed approach and conventional methods are compared to demonstrate the effectiveness of the proposed approach. Simulation and experimental results for a seven-level cascaded H-bridge STATCOM system are presented to verify the usability and reliability of the proposed approach. Auteurs: Yonglei Zhang;XiaoJie Wu;Xibo Yuan; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7634 - 7644 Editeur: IEEE Document complet vers site de l'éditeur
» A Simplified Method for Retrieving Aerosol Optical Thickness Using Visibility Data Between 1980 and 2014, A Case Study in China
 Résumé:Analysis of long-term variations of aerosol optical thickness (AOT) is essential to understand the climate change and earth radiation budget. A simplified method was developed in this study to derive the AOT using more than thirty-year surface visibility and aerosol vertical distribution from LiDAR climatology of vertical aerosol structure for space-based LiDAR simulation studies data. Moderate resolution imaging spectroradiometer (MODIS) TERRA and AQUA daily measurements were used to evaluate the performance of the inferred AOT. Results show that the correlations of monthly AOT between MODIS measurements and inferred data are higher than 0.59 and the annual AOT values have stronger correlations (r > 0.82) than monthly data. The inferred AOT can capture the general spatial distribution similar to satellite images with long-term scale. The correlation of seasonal variation between two datasets is also higher than 0.77. The root mean squared error of inferred AOT relative to MODIS AOT is about 0.22 and 0.11 for monthly and yearly data, respectively. Analysis using singular value decomposition shows that the inferred AOT is consistent with MODIS measurements during 2002–2014 spatially and temporally. The average annual AOT in over 200 stations in China between 1980 and 2014 shows generally upward trends. Results from this paper can be used for further analysis of the aerosol effects on climate change in a regional scale. Auteurs: Zhao Yang Zhang;Man Sing Wong; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4409 - 4416 Editeur: IEEE Document complet vers site de l'éditeur
» A Sizing Methodology for Rise-Time Minimization of Dickson Charge Pumps With Capacitive Loads
 Résumé:A novel sizing methodology for Dickson charge pumps with pure capacitive loads is presented. The methodology is based on dynamic analysis to minimize the rise time of the charge pump up to 25% under a given circuit area. The methodology is validated through the implementation of a six-stage charge pump-based driver in 180-nm standard low-voltage CMOS technology. The driver is used for the excitation of ultrasonic transducers with 34 V at a resonance frequency of 220 KHz. A rise time of only 512 nS is achieved. The driver consumes 10.6 mA drawn from a 5-V supply at a pumping frequency of 50 MHz and occupies an area of 0.2 mm2. Auteurs: Ahmed Saeed;Sameh Ibrahim;Hani Fikry Ragai; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1202 - 1206 Editeur: IEEE Document complet vers site de l'éditeur
» A Solution to Press-Pack Packaging of SiC MOSFETS
 Résumé:This paper proposes a packaging method for SiC MOSFETs that provides a feasible solution of implementing press-pack packaging on SiC MOSFETs to extend the application of SiC devices into the high power range. The challenges in realizing press-pack packaging of SiC MOSFETs are addressed, and the solutions are proposed that fit the specific requirements of SiC MOSFET. To achieve pressure contact on SiC MOSFETs, miniature and flexible press pins called “fuzz buttons” are used in a low-profile interposer to realize die top side connection. Since the press-pack does not provide internal insulation between the active device and the heatsink, the heatsink is included in the power loop. To avoid large parasitic loop inductance being introduced by the heatsinks, a microchannel heatsink is developed which has a low thickness while remaining adequate heat dissipation efficiency. The structure and assembly process flow of the press-pack SiC MOSFET are provided. A half-bridge stack prototype with two press-packs and three heatsinks is developed. The thermal and electrical performances of the press-pack and the half-bridge stack are evaluated by simulations and tests to validate the feasibility of the proposed packaging approach. Auteurs: Nan Zhu;H. Alan Mantooth;Dehong Xu;Min Chen;Michael D. Glover; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8224 - 8234 Editeur: IEEE Document complet vers site de l'éditeur
» A Sparse Bayesian Learning Approach for Through-Wall Radar Imaging of Stationary Targets
 Résumé:Through-the-wall radar (TWR) imaging is an emerging technology that enables detection and localization of targets behind walls. In practical operations, TWR sensing faces several technical difficulties including strong wall clutter and missing data measurements. This paper proposes a sparse Bayesian learning (SBL) approach for wall-clutter mitigation and scene reconstruction from compressed data measurements. In the proposed approach, SBL is used to model both the intraantenna signal sparsity and interantenna signal correlation for estimating the antenna signals jointly. Here, the Bayesian framework provides a learning paradigm for sharing measurements among spatial positions, leading to accurate and stable antenna signal estimation. Furthermore, the task of wall-clutter mitigation is formulated as a probabilistic inference problem, where the wall-clutter subspace and its dimension are learned automatically using the mechanism of automatic relevant determination. Automatic discrimination between targets and clutter allows an effective target image formation, which is performed using Bayesian approximation. Experimental results with both real and simulated TWR data demonstrate the effectiveness of the SBL approach in indoor target detection and localization. Auteurs: Van Ha Tang;Son Lam Phung;Fok Hing Chi Tivive;Abdesselam Bouzerdoum; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2485 - 2501 Editeur: IEEE Document complet vers site de l'éditeur
» A Sparse Learning Framework for Joint Effect Analysis of Copy Number Variants
 Résumé:Copy number variants (CNVs), including large deletions and duplications, represent an unbalanced change of DNA segments. Abundant in human genomes, CNVs contribute to a large proportion of human genetic diversity, with impact on many human phenotypes. Although recent advances in genetic studies have shed light on the impact of individual CNVs on different traits, the analysis of joint effect of multiple interactive CNVs lags behind from many perspectives. A primary reason is that the large number of CNV combinations and interactions in the human genome make it computationally challenging to perform such joint analysis. To address this challenge, we developed a novel sparse learning framework that combines sparse learning with biological networks to identify interacting CNVs with joint effect on particular traits. We showed that our approach performs well in identifying CNVs with joint phenotypic effect using simulated data. Applied to a real human genomic dataset from the 1,000 Genomes Project, our approach identified multiple CNVs that collectively contribute to population differentiation. We found a set of multiple CNVs that have joint effect in different populations, and affect gene expression differently in distinct populations. These results provided a collection of CNVs that likely have downstream biomedical implications in individuals from diverse population backgrounds. Auteurs: Zhiyong Wang;Benika Hall;Jinbo Xu;Xinghua Shi; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1013 - 1027 Editeur: IEEE Document complet vers site de l'éditeur
» A Stand-Alone Approach for High-Sensitivity GNSS Receivers in Signal-Challenged Environment
» A State of Charge Estimation Method Based on $H_\infty$ Observer for Switched Systems of Lithium-Ion Nickel–Manganese–Cobalt Batteries
 Résumé:Accurately estimating the state of charge (SOC) of the battery is the basis of battery management system. Based on a linear equivalent circuit model, this paper has introduced a switched battery model to model the complicated physical and chemical reactions properties. The SOC is determined by the battery electromotive force at a present battery state that is estimated through the H∞ switched observer for dealing with the inexact or unknown statistical properties of the modeling and measurement errors. The observer design criterion is presented to ensure the H∞ performance of the switched observer. Then, the proposed method is applied successfully to estimate the SOC by utilizing the current and terminal voltage. Finally, the experimental results have demonstrated that the proposed method can provide high accuracy and robustness for SOC estimation. Auteurs: Cong-zhi Liu;Qiao Zhu;Liang Li;Wei-qun Liu;Ling-Yan Wang;Neng Xiong;Xiang-yu Wang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8128 - 8137 Editeur: IEEE Document complet vers site de l'éditeur
» A Study on Piezoelectric Energy-Harvesting Wireless Sensor Networks Deployed in a Weak Vibration Environment
 Résumé:Wireless sensor network (WSN) is an interestingly promising technology with many applications in intelligent environment-monitoring. Its energy consumption is, however, essentially challenged after it is deployed. In this paper, we developed a low-resonant-frequency piezoelectric energy harvesting device as an alternative to power WSN deployed in a weak vibration environment. An energy management module, equipped with a full-bridge rectifier (FBR), a fully self-powered voltage controller, and a logic-level protection circuit was designed to enable a regulated voltage to intermittently drive WSN for temperature monitoring. The power transfer efficiency of FBR reached 42%, presenting a good performance/cost ratio in the case of a relatively high open-circuit voltage of 8 V and a low rectified voltage of 3.3 V. The experimental results have demonstrated that the proposed WSN was successfully driven at an interval time of less than 1 min, and fully self-powered by the scavenged energy from the environmental vibration source of a 0.15-g acceleration and a 40-Hz vibration frequency. Auteurs: Yanhui Han;Yue Feng;Zejie Yu;Wenzhong Lou;Huicong Liu; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6770 - 6777 Editeur: IEEE Document complet vers site de l'éditeur
» A Subspace Approach to Spectral Quantification for MR Spectroscopic Imaging
 Résumé:Objective: To provide a new approach to spectral quantification for magnetic resonance spectroscopic imaging (MRSI), incorporating both spatial and spectral priors. Methods: A novel signal model is proposed, which represents the spectral distributions of each molecule as a subspace and the entire spectrum as a union of subspaces. Based on this model, the spectral quantification can be solved in two steps: 1) subspace estimation based on the empirical distributions of the spectral parameters estimated using spectral priors; and 2) parameter estimation for the union-of-subspaces model incorporating spatial priors. Results: The proposed method has been evaluated using both simulated and experimental data, producing impressive results. Conclusion: The proposed union-of-subspaces representation of spatiospectral functions provides an effective computational framework for solving the MRSI spectral quantification problem with spatiospectral constraints. Significance: The proposed approach transforms how the MRSI spectral quantification problem is solved and enables efficient and effective use of spatiospectral priors to improve parameter estimation. The resulting algorithm is expected to be useful for a wide range of quantitative metabolic imaging studies using MRSI. Auteurs: Yudu Li;Fan Lam;Bryan Clifford;Zhi-Pei Liang; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2486 - 2489 Editeur: IEEE Document complet vers site de l'éditeur
» A Sugiyama-Like Decoding Algorithm for Convolutional Codes
 Résumé:We propose a decoding algorithm for a class of convolutional codes called skew Reed-Solomon convolutional codes. These are convolutional codes of designed Hamming distance endowed with a cyclic structure yielding a left ideal of a non-commutative ring (a quotient of a skew polynomial ring). In this setting, right and left division algorithms exist, so our algorithm follows the guidelines of the Sugiyama’s procedure for finding the error locator and error evaluator polynomials for Goppa block codes. Auteurs: José Gómez-Torrecillas;F. J. Lobillo;Gabriel Navarro; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6216 - 6226 Editeur: IEEE Document complet vers site de l'éditeur
» A Survey of GNSS-Based Research and Developments for the European Railway Signaling
 Résumé:Railways have already introduced satellite-based localization systems for non-safety related applications. Driven by economic reasons, the use of these systems for new services and, in particular, their introduction in signaling system is seriously investigated today and tested all around the world. Because of the weight of their history, their strong normative context, and the high requested level of safety, the introduction is relatively slow. The aim of this paper is to provide a survey of past and current programs dealing with global navigation satellite systems as a basis to introduce main issues relative to context, standards, performance requirements, and safety proofs. Links with aeronautical concepts are also presented, illustrating the transposable principles and the limits due to the land transport environment. Auteurs: Juliette Marais;Julie Beugin;Marion Berbineau; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2602 - 2618 Editeur: IEEE Document complet vers site de l'éditeur
» A Survey of Train Positioning Solutions
 Résumé:Positioning accurately and safely a train is nowadays a great challenge. That includes currently available railway sensors and new candidate sensors for data fusion. Global Navigation Satellite System and Inertial Measurement Unit sensors arise as prominent technologies to incorporate in railways. Although satellite-based train localization tests can be found in the scientific literature, there are no common criteria to evaluate the performance of the positioning achieved. In this paper, a series of criteria is defined and justified in order to be able to evaluate the most recent and relevant works related to train positioning. The results of this comparative analysis are gathered in tables, where the criteria defined are applied to the works compiled. According to the results obtained, a research gap in safety related applications is found. It is concluded that the economic viability of given solutions should be explored, so as to design an on-board train-integrated positioning system. Auteurs: Jon Otegui;Alfonso Bahillo;Iban Lopetegi;Luis Enrique Díez; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6788 - 6797 Editeur: IEEE Document complet vers site de l'éditeur
» A Survey on Non-Orthogonal Multiple Access for 5G Networks: Research Challenges and Future Trends
 Résumé:Non-orthogonal multiple access (NOMA) is an essential enabling technology for the fifth-generation (5G) wireless networks to meet the heterogeneous demands on low latency, high reliability, massive connectivity, improved fairness, and high throughput. The key idea behind NOMA is to serve multiple users in the same resource block, such as a time slot, subcarrier, or spreading code. The NOMA principle is a general framework, and several recently proposed 5G multiple access schemes can be viewed as special cases. This survey provides an overview of the latest NOMA research and innovations as well as their applications. Thereby, the papers published in this special issue are put into the context of the existing literature. Future research challenges regarding NOMA in 5G and beyond are also discussed. Auteurs: Zhiguo Ding;Xianfu Lei;George K. Karagiannidis;Robert Schober;Jinhong Yuan;Vijay K. Bhargava; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 10.-2017, volume: 35, issue:10, pages: 2181 - 2195 Editeur: IEEE Document complet vers site de l'éditeur
» A Switched Reluctance Motor Drive Using Photovoltaic Transistors: Principle, Prototype, Experimental, and Numerical Results
 Résumé:A solar-powered switch reluctance motor drive using photovoltaic transistors (PVTs) is presented. The expression “PVT” is used to designate a conventional photovoltaic (PV) cell used as a light-controlled power transistor. To obtain a motor drive, a set of PVTs controls the current fed from an external dc power source to the motor phases. The control is achieved by modulating the sunlight hitting the PVTs using a shutter driven by the motor rotor. If the external dc source is a solar panel, the resulting system is able to convert light energy into mechanical energy, without the need of any brushes or other power electronics components. This system could be more affordable and reliable than conventional ones, and therefore, is well suited for off-grid applications like water pumping. This paper first discusses the operation of a PVT through the proposition and the validation of a model. Then, the operating principle of a PVT inverter is clarified. Finally, experimental and numerical results on the first PVT inverter-fed switched reluctance motor are reported. A prototype was built using a switched reluctance motor 6/4 and 12 PVTs. It was here connected to an external 12 V dc power source as a step before using a solar PV source. Results that the PVT inverter-fed switched reluctance motor was operating as expected and provided useful power. Auteurs: Loïc Quéval;Alain Coty;Lionel Vido;Raimund Gottkehaskamp;Bernard Multon; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4886 - 4893 Editeur: IEEE Document complet vers site de l'éditeur
» A Tale of Ten Cities: Characterizing Signatures of Mobile Traffic in Urban Areas
 Résumé:Urban landscapes present a variety of socio-topological environments that are associated to diverse human activities. As the latter affect the way individuals connect with each other, a bound exists between the urban tissue and the mobile communication demand. In this paper, we investigate the heterogeneous patterns emerging in the mobile communication activity recorded within metropolitan regions. To that end, we introduce an original technique to identify classes of mobile traffic signatures that are distinctive of different urban fabrics. Our proposed technique outperforms previous approaches when confronted to ground-truth information, and allows characterizing the mobile demand in greater detail than that attained in the literature to date. We apply our technique to extensive real-world data collected by major mobile operators in 10 cities. Results unveil the diversity of baseline communication activities across countries, but also provide evidence of the existence of a number of mobile traffic signatures that are common to all studied areas and specific to particular land uses. Auteurs: Angelo Furno;Marco Fiore;Razvan Stanica;Cezary Ziemlicki;Zbigniew Smoreda; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2682 - 2696 Editeur: IEEE Document complet vers site de l'éditeur
» A Technique for Efficient Query Estimation over Distributed Data Streams
 Résumé:Distributed data stream mining in a sliding window has emerged recently, due to its applications in many domains including large Telecoms and Internet Service Providers, financial tickers, ATM and credit card operations in banks and transactions in retail chains. Many of these large-scale applications prohibit monitoring data centrally at a single location due to their massive volume of the data; therefore, data acquisition, processing, and mining tasks are often distributed to a number of processing nodes, which monitor their local streams and exchange only the summary of data either periodically or on demand. While this offer many advantages, distributed stream applications possess significant challenges including problems related to an online analysis of the recent data, communication efficiency and various estimation of various complex queries. There are few existing techniques which solve problems related to distributed sliding window data stream; however, those techniques are focused on solving only simple problems and require high space, query, and communication cost, which can be a bottleneck for many of these large scale applications. In this paper, we propose an efficient query estimation technique by constructing a small sketch of the data stream. The constructed sketch uses a deterministic sliding window model and can estimate various complex queries, for both centralized and distributed applications; including point queries (i.e., range queries and heavy hitter queries), quantiles, inner product, and self-join size queries, with deterministic guarantees on the precision. The proposed approach improves upon recent existing work for these problems, in terms of the memory and query cost in a centralized setting and in terms of communication cost and merge complexity in a distributed setting. It requires $O(\frac{1}{\epsilon ^2}\log {(\epsilon N)})$ - inline-graphic xlink:href="mahmood-ieq1-2693983.gif"/> memory (where $0<\epsilon <1$ is a user defined parameter), can provide estimates in $O(1)$ time, and processes each incoming record in $O(1)$ amortized time. Detailed experimental analysis, both in centralized and distributed settings demonstrates that in practice the proposed approach uses about six times less memory, and has about eight times less query time when compared to ECM sketches. In a distributed application, the proposed technique also significantly improves (around seven times) on the communication cost between distributed sites. Auteurs: Zubair Shah;Abdun Naser Mahmood;Zahir Tari;Albert Y. Zomaya; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2770 - 2783 Editeur: IEEE Document complet vers site de l'éditeur
» A Thermal Ink-Jet Printer Head Prototype With Full Carbon Based Microbubble Generator
 Résumé:This paper presents the development of a novel thermal ink-jet printer head prototype using full carbon-based microbubble generators with carbon nanotubes as heating elements and graphene as electrodes. Meanwhile, each microbubble generator is equipped with a carbon nanotube sensor to real-timely probe the temperature of its surrounding micro-environment. With an array of microbubble generators and sensors fabricated on quartz glass, as well as a microfluidic structure constructed by the micromachined silicon, the printer head prototype is formed by an anodic silicon-glass bonding process with several scattered graphene film flakes as medium. Droplet ejection with volume as tiny as ~0.03 pl corresponding to a very high spatial resolution of >2000 dpi driven by two microbubble valves is demonstrated by the printing unit in the prototype. Increasing the input power cannot only speed up the bubble nucleation and growth, but also improve the utilizing efficiency of electric heating energy. The experimental detected temperature variation in the printing unit reveals its nonlinear heat convection property by comparison with the theoretical calculation by finite-element analysis. [2017-0048] Auteurs: Yunhong Xiang;Lvhui Jiang;Yu Zhu;Changsheng Chen;Yangyang Chen;Wenli Zhou; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1040 - 1046 Editeur: IEEE Document complet vers site de l'éditeur
» A Tight Upper Bound on the Second-Order Coding Rate of the Parallel Gaussian Channel With Feedback
 Résumé:This paper investigates the asymptotic expansion for the maximum rate of fixed-length codes over a parallel Gaussian channel with feedback under the following setting: a peak power constraint is imposed on every transmitted codeword, and the average error probabilities of decoding the transmitted message are non-vanishing as the blocklength increases. The main contribution of this paper is a self-contained proof of an upper bound on the first- and second-order asymptotics of the parallel Gaussian channel with feedback. The proof techniques involve developing an information spectrum bound followed by using Curtiss’ theorem to show that a sum of dependent random variables associated with the information spectrum bound converges in distribution to a sum of independent random variables, thus facilitating the use of the usual central limit theorem. Combined with existing achievability results, our result implies that the presence of feedback does not improve the first- and second-order asymptotics. Auteurs: Silas L. Fong;Vincent Y. F. Tan; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6474 - 6486 Editeur: IEEE Document complet vers site de l'éditeur
» A TLM-Based Wideband Adjoint Variable Method for Sensitivity Analysis of Non-Dispersive Anisotropic Structures
 Résumé:We propose a wideband theory for adjoint variable sensitivity analysis of problems with non-dispersive anisotropic materials. The method is developed based on the transmission line modeling (TLM) technique. The anisotropic material property can be the full tensors of permittivity, permeability, electrical conductivity, magnetic resistivity, magnetoelectric coupling, or electromagnetic coupling. The tensors are assumed constant and may contain non-diagonal elements. Our algorithm estimates the gradient of the desired response with respect to all the designable parameters using at most one extra simulation, regardless of the number of parameters. The theory has been implemented in an algorithm for 2-D and 3-D structures. Our estimated sensitivities match well the computationally expensive central finite difference approximations. Auteurs: Laleh Seyyed Kalantari;Osman S. Ahmed;Mohamed H. Bakr;Natalia K. Nikolova; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5267 - 5278 Editeur: IEEE Document complet vers site de l'éditeur
» A Trust Label System for Communicating Trust in Cloud Services
 Résumé:Cloud computing is rapidly changing the digital service landscape. A proliferation of Cloud providers has emerged, increasing the difficulty of consumer decisions. Trust issues have been identified as a factor holding back Cloud adoption. The risks and challenges inherent in the adoption of Cloud services are well recognised in the computing literature. In conjunction with these risks, the relative novelty of the online environment as a context for the provision of business services can increase consumer perceptions of uncertainty. This uncertainty is worsened in a Cloud context due to the lack of transparency, from the consumer perspective, into the service types, operational conditions and the quality of service offered by the diverse providers. Previous approaches failed to provide an appropriate medium for communicating trust and trustworthiness in Clouds. A new strategy is required to improve consumer confidence and trust in Cloud providers. This paper presents the operationalisation of a trust label system designed to communicate trust and trustworthiness in Cloud services. We describe the technical details and implementation of the trust label components. Based on a use case scenario, an initial evaluation was carried out to test its operations and its usefulness for increasing consumer trust in Cloud services. Auteurs: Vincent C. Emeakaroha;Kaniz Fatema;Lisa van der Werff;Philip Healy;Theo Lynn;John P. Morrison; Apparue dans: IEEE Transactions on Services Computing Date publication: 10.-2017, volume: 10, issue:5, pages: 689 - 700 Editeur: IEEE Document complet vers site de l'éditeur
» A Two-Level Game Theory Approach for Joint Relay Selection and Resource Allocation in Network Coding Assisted D2D Communications
 Résumé:Device-to-device (D2D) communication, which enables direct transmissions between mobile devices to improve spectrum efficiency, is one of the preferable candidate technologies for the next generation cellular network. Network coding, on the other hand, is widely used to improve throughput in ad hoc networks. Thus, the performance of D2D communications in cellular networks can potentially benefit from network coding. Aiming to improve the achievable capacity of D2D communications, we propose a system with inter-session network coding enabled to assist D2D transmissions. We formulate the joint problem of relay selection and resource allocation in network coding assisted D2D communications, and obtain the overall capacity of the network under complex interference conditions as a function of the relay selection and resource allocation. To solve the formulated problem, we propose a two-level decentralized approach termed NC-D2D, which solves the relay selection and resource allocation problems alternatively to obtain stable solutions for these two problems. Specifically, a coalition formation game associates relays with D2D pairs to enable network coding aided transmissions, and a greedy algorithm based game allocates limited cellular resources to D2D pairs and relays in NC-D2D, respectively. The performances of the proposed scheme is evaluated through extensive simulations to prove its superiority. Auteurs: Chuhan Gao;Yong Li;Yulei Zhao;Sheng Chen; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2697 - 2711 Editeur: IEEE Document complet vers site de l'éditeur
» A Two-Line Time-Domain Gating Method for Characterization of Test Fixture With via Hole Discontinuity
 Résumé:The time-domain gating method (TGM) is an accurate and useful method to characterize the test fixtures used in the measurement of high-speed connectors. However, its accuracy can be degraded by the gating error when the test fixture contains the impedance discontinuity near the fixture end facing the device under test. To overcome this limitation, this letter proposes a two-line TGM (2LTGM) for characterizing the test fixtures having the discontinuities such as via holes. The proposed method does not require any modification of the test fixtures with the help of the proposed test structures and T-parameter extraction procedure. The experimental results show that the proposed 2LTGM has an 8 dB lower mean square error than the conventional TGM for the test fixtures having via hole discontinuities at the end. We expect that the 2LTGM can improve the accuracy for characterizing the test fixtures with any discontinuities not limited to the via holes. Auteurs: Jaeyong Cho;Byung-Sung Kim;Jonghyuck Jeong;Junseong Kim;Kibeom Kim;Karam Hwang;Hwiseob Lee;Seungil Jeung;Seungyoung Ahn; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 936 - 938 Editeur: IEEE Document complet vers site de l'éditeur
» A Unification of Intuitionistic Fuzzy Calculus Theories Based on Subtraction Derivatives and Division Derivatives
 Résumé:Intuitionistic fuzzy calculus replaces real numbers in classical calculus with intuitionistic fuzzy numbers that are the basic elements of Atanassov's intuitionistic fuzzy sets. Intuitionistic fuzzy calculus consists of two parallel parts, which are respectively developed based on the subtraction derivatives and the division derivatives. This paper focuses on building the relationships between the two independent intuitionistic fuzzy calculus theories, and unifying them into a whole theory. Auteurs: Qian Lei;Zeshui Xu; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1023 - 1040 Editeur: IEEE Document complet vers site de l'éditeur
» A Unified Framework for Deterministic and Probabilistic $\mathscr {D}$-Stability Analysis of Uncertain Polynomial Matrices
 Résumé:In control theory, we are often interested in robust $\mathscr {D}$ -stability analysis, which aims at verifying if all the eigenvalues of an uncertain matrix lie in a given region $\mathscr {D}$. Although many algorithms have been developed to provide conditions for an uncertain matrix to be robustly $\mathscr {D}$-stable, the problem of computing the probability of an uncertain matrix to be $\mathscr {D}$ -stable is still unexplored. The goal of this paper is to fill this gap in two directions. First, the only constraint on the stability region $\mathscr {D}$ that we impose is that its complement is a semialgebraic set. This comprises many important cases in robust control theory. Second, the $\mathscr {D}$-stability analysis problem is formulated in a probabilistic framework, by assuming that only few probabilistic information is available on the uncertain parameters, such as support and some moments. We will show how to compute the minimum probability that the matrix is $\mathscr {D}$-stable by using convex relaxations based on the theory of moments. Auteurs: Dario Piga;Alessio Benavoli; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5437 - 5444 Editeur: IEEE Document complet vers site de l'éditeur
» A Unified Framework for Deterministic and Probabilistic $\mathscr {D}$-Stability Analysis of Uncertain Polynomial Matrices
 Résumé:In control theory, we are often interested in robust $\mathscr {D}$ -stability analysis, which aims at verifying if all the eigenvalues of an uncertain matrix lie in a given region $\mathscr {D}$. Although many algorithms have been developed to provide conditions for an uncertain matrix to be robustly $\mathscr {D}$-stable, the problem of computing the probability of an uncertain matrix to be $\mathscr {D}$ -stable is still unexplored. The goal of this paper is to fill this gap in two directions. First, the only constraint on the stability region $\mathscr {D}$ that we impose is that its complement is a semialgebraic set. This comprises many important cases in robust control theory. Second, the $\mathscr {D}$-stability analysis problem is formulated in a probabilistic framework, by assuming that only few probabilistic information is available on the uncertain parameters, such as support and some moments. We will show how to compute the minimum probability that the matrix is $\mathscr {D}$-stable by using convex relaxations based on the theory of moments. Auteurs: Dario Piga;Alessio Benavoli; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5437 - 5444 Editeur: IEEE Document complet vers site de l'éditeur
» A Unified Framework for Deterministic and Probabilistic $\mathscr {D}$-Stability Analysis of Uncertain Polynomial Matrices
 Résumé:In control theory, we are often interested in robust $\mathscr {D}$ -stability analysis, which aims at verifying if all the eigenvalues of an uncertain matrix lie in a given region $\mathscr {D}$. Although many algorithms have been developed to provide conditions for an uncertain matrix to be robustly $\mathscr {D}$-stable, the problem of computing the probability of an uncertain matrix to be $\mathscr {D}$ -stable is still unexplored. The goal of this paper is to fill this gap in two directions. First, the only constraint on the stability region $\mathscr {D}$ that we impose is that its complement is a semialgebraic set. This comprises many important cases in robust control theory. Second, the $\mathscr {D}$-stability analysis problem is formulated in a probabilistic framework, by assuming that only few probabilistic information is available on the uncertain parameters, such as support and some moments. We will show how to compute the minimum probability that the matrix is $\mathscr {D}$-stable by using convex relaxations based on the theory of moments. Auteurs: Dario Piga;Alessio Benavoli; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5437 - 5444 Editeur: IEEE Document complet vers site de l'éditeur
» A Unified Framework for Deterministic and Probabilistic $\mathscr {D}$-Stability Analysis of Uncertain Polynomial Matrices
 Résumé:In control theory, we are often interested in robust $\mathscr {D}$ -stability analysis, which aims at verifying if all the eigenvalues of an uncertain matrix lie in a given region $\mathscr {D}$. Although many algorithms have been developed to provide conditions for an uncertain matrix to be robustly $\mathscr {D}$-stable, the problem of computing the probability of an uncertain matrix to be $\mathscr {D}$ -stable is still unexplored. The goal of this paper is to fill this gap in two directions. First, the only constraint on the stability region $\mathscr {D}$ that we impose is that its complement is a semialgebraic set. This comprises many important cases in robust control theory. Second, the $\mathscr {D}$-stability analysis problem is formulated in a probabilistic framework, by assuming that only few probabilistic information is available on the uncertain parameters, such as support and some moments. We will show how to compute the minimum probability that the matrix is $\mathscr {D}$-stable by using convex relaxations based on the theory of moments. Auteurs: Dario Piga;Alessio Benavoli; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5437 - 5444 Editeur: IEEE Document complet vers site de l'éditeur
» A Versatile and Accurate Compact Model of Memristor With Equivalent Resistor Topology
 Résumé:Memristor appeals to a wide research field as the fourth passive element, and its model has been a necessary topic for future circuit applications. In this letter, a novel compact model of memristor, based on the equivalent resistor topology of variable conductive filaments, is presented. Since the formation and annihilation of conductive filaments is a natural mechanism of mainstream memristor, the model is essential and so more accurate than those nonlinear dopant drift models. On the other hand, the equivalent resistor idea makes our model versatile and efficient comparing with some complex physical process methods, and fulfills the requirements of circuit design. The versatility and accuracy of our compact model have been verified by the results that it can reduce at least 30% error in a Pt/TiO2/TiO2+x/Pt type memristor and at least 20% error in a Ta/TaOx/Pt type memristor, comparing with some popular models. Moreover it is easier to be implemented in Verilog-A, which possesses more flexibility and higher applicability in circuit design. Auteurs: Ruohua Zhu;Sheng Chang;Hao Wang;Qijun Huang;Jin He;Fan Yi; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1367 - 1370 Editeur: IEEE Document complet vers site de l'éditeur
» A Versatile Noise Performance Metric for Electrical Impedance Tomography Algorithms
 Résumé:Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring of patients under mechanical ventilation. EIT has the potential to offer continuous medical monitoring while being noninvasive, radiation free, and low cost. Due to their ill-posedness, image reconstruction typically uses regularization, which implies a hyperparameter controlling the tradeoff between noise rejection and resolution or other accuracies. In order to compare reconstruction algorithms, it is common to choose hyperparameter values such that the reconstructed images have equal noise performance (NP), i.e., the amount of measurement noise reflected in the images. For EIT many methods have been suggested, but none work well when the data originate from different measurement setups, such as for different electrode positions or measurement patterns. To address this issue, we propose a new NP metric based on the average signal-to-noise ratio in the image domain. The approach is validated for EIT using simulation experiments on a human thorax model and measurements on a resistor phantom. Results show that the approach is robust to the measurement configuration (i.e., number and position of electrodes, skip pattern) and the reconstruction algorithm used. We propose this novel approach as a way to select optimized measurement configurations and algorithms. Auteurs: Fabian Braun;Martin Proença;Josep Solà;Jean-Philippe Thiran;Andy Adler; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2321 - 2330 Editeur: IEEE Document complet vers site de l'éditeur
» A Wafer Prealignment Algorithm Based on Fourier Transform and Least Square Regression
 Résumé:Automatic wafer prealignment is an important process in wafer manufacturing, whereby its flat edge is set at a predefined angle and its center is set in a predefined position; translational and rotational movement compensate for deviation of the wafer. However, as the traditional wafer prealignment algorithm depends on marked templates at the training stage when the type of wafer is changed, the templates need to be retrained. This paper proposes a new wafer prealignment algorithm, based on Fourier transform for orientation prealignment and least square regression for position prealignment, which will automatically adapt to different types of wafers in 2-D space. Results from experiments with the proposed algorithm on a laser-scribing machine using two types of wafer show that the orientation prealignment achieved an accuracy of 0.05°, the position prealignment achieved an accuracy of 5 pixels, and the average operation time was approximately 1.5 s. As prealignment algorithm therefore meets real-time efficiency and precision requirements, it is suitable for use with semiconductor devices.Note to Practitioners—Because deviation appears when a wafer is first put on the working table, the traditional process is to set up a prealignment system when aligning a new type of wafer. However, different templates increase difficulty for machine operators, and decrease automation and reliability of the devices. This paper therefore proposes a new general prealignment algorithm based on using Fourier transform for orientation prealignment and least square regression for position prealignment. The algorithm was tested on two types of wafer with results showing that the orientation prealignment achieved an accuracy of 0.05°, the position prealignment achieved an accuracy of 5 pixels, and the average operation time was about 1.5 s, all of which meet real-time requirements. Although the alg- rithm can be adapted to different wafers without adjustment, it does not fit nonquadrilateral chips very well. Accordingly, we will develop an improved algorithm with better generality in due course. Auteurs: Jiayu Xu;Hong Hu;Yulin Lei;Huaiyuan Liu; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1771 - 1777 Editeur: IEEE Document complet vers site de l'éditeur
» A Wideband Bandpass Filter With Reconfigurable Bandwidth Based on Cross-Shaped Resonator
 Résumé:A wideband bandpass filter (BPF) with reconfigurable bandwidth (BW) is proposed based on a parallel-coupled line structure and a cross-shaped resonator with open stubs. The p-i-n diodes are used as the tuning elements, which can implement three reconfigurable BW states. The prototype of the designed filter reports an absolute BW tuning range of 1.22 GHz, while the fractional BW is varied from 34.8% to 56.5% when centered at 5.7 GHz. The simulation and measured results are in good agreement. Comparing with previous works, the proposed reconfigurable BPF features wider BW tuning range with maximum number of tuning states. Auteurs: Teng Cheng;Kam-Weng Tam; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 909 - 911 Editeur: IEEE Document complet vers site de l'éditeur
» Absolute Electroluminescence Imaging Diagnosis of GaAs Thin-Film Solar Cells
 Résumé:A spatially resolved absolute electroluminescence (EL) imaging method was utilized to analyze the photovoltaic properties and resistive loss properties of a GaAs thin-film solar cell. The I–V relation was extrapolated from the absolute EL efficiency measurements in conjunction with the external-quantum-efficiency (EQE) measurements; the EL extrapolated I–V relation has a merit over the conventional I–V relation measured with a solar simulator that it could eliminate the series resistance effect caused by external probe contact. Then, the mapping of the internal voltage of the solar cell and the sheet resistance of the window layer of the solar cell were obtained from the calibrated absolute EL imaging method. Finally, optic electroconversion losses of the solar cell including radiative loss, nonradiative loss, thermalization loss, transmission loss, and junction loss were quantified given by the EL and EQE measurements. Auteurs: XiaoBo Hu;Tengfei Chen;Juanjuan Xue;Guoen Weng;Shaoqiang Chen;Hidefumi Akiyama;Ziqiang Zhu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» AC-Inductors Design for a Modular Multilevel TSBC Converter, and Performance of a Low-Speed High-Torque Motor Drive Using the Converter
 Résumé:This paper provides a theoretical and experimental discussion on ac-inductors design for a modular multilevel triple-star bridge-cells (TSBC) converter, or shortly a TSBC converter. This converter requires multiple ac inductors for controlling nine cluster currents. This paper proposes three three-legged, six-winding, “interzigzag” inductors for the TSBC converter. Since each leg of the individual inductor has two windings, the three inductors have 18 windings in total. The wire leads are zigzagged among the three inductors. This unique structure of the “interzigzag” windings leads to the following feature: Both three-phase supply and motor currents produce no magnetic flux in each of the nine legs. This feature makes each inductor smaller in size and lighter in weight. A specially-designed downscaled motor-drive system rated at 400 V and 15 kW is constructed and tested to confirm the validity of a design of the proposed inductors, as well as to verify transient motor-drive performance during four-quadrant operation. Auteurs: Wataru Kawamura;Makoto Hagiwara;Hirofumi Akagi;Masahiko Tsukakoshi;Ritaka Nakamura;Sumiyasu Kodama; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4718 - 4729 Editeur: IEEE Document complet vers site de l'éditeur
» Accelerating Recurrent Neural Networks: A Memory-Efficient Approach
 Résumé:Recurrent neural networks (RNNs) have achieved the state-of-the-art performance on various sequence learning tasks due to their powerful sequence modeling capability. However, RNNs usually require a large number of parameters and high computational complexity. Hence, it is quite challenging to implement complex RNNs on embedded devices with stringent memory and latency requirement. In this paper, we first present a novel hybrid compression method for a widely used RNN variant, long–short term memory (LSTM), to tackle these implementation challenges. By properly using circulant matrices, forward nonlinear function approximation, and efficient quantization schemes with a retrain-based training strategy, the proposed compression method can reduce more than 95% of memory usage with negligible accuracy loss when verified under language modeling and speech recognition tasks. An efficient scalable parallel hardware architecture is then proposed for the compressed LSTM. With an innovative chessboard division method for matrix–vector multiplications, the parallelism of the proposed hardware architecture can be freely chosen under certain latency requirement. Specifically, for the circulant matrix–vector multiplications employed in the compressed LSTM, the circulant matrices are judiciously reorganized to fit in with the chessboard division and minimize the number of memory accesses required for the matrix multiplications. The proposed architecture is modeled using register transfer language (RTL) and synthesized under the TSMC 90-nm CMOS technology. With 518.5-kB on-chip memory, we are able to process a $512 \times 512$ compressed LSTM in 1.71 $\mu {{{\text{s}}}}$ , corresponding to 2.46 TOPS on the uncompressed one, at a cost of 30.77-mm2 chi- area. The implementation results demonstrate that the proposed design can achieve significantly high flexibility and area efficiency, which satisfies many real-time applications on embedded devices. It is worth mentioning that the memory-efficient approach of accelerating LSTM developed in this paper is also applicable to other RNN variants. Auteurs: Zhisheng Wang;Jun Lin;Zhongfeng Wang; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2763 - 2775 Editeur: IEEE Document complet vers site de l'éditeur
» Acceleration of the WRF Monin–Obukhov–Janjic Surface Layer Parameterization Scheme on an MIC-Based Platform for Weather Forecast
 Résumé:A state-of-the-art numerical weather prediction (NWP) model, comprising weather research and forecast (WRF) model and analysis techniques, has been extensively exercised for weather prophecy all over the world. The WRF model, the soul role in NWP, constitutes dynamic solvers and elaborate physical components for conducting fluid behavior, all of which are sketched for both atmospheric research analyses and operational weather foretell. One salient physical ingredient in WRF is the surface layer simulation, which provides surface heat and moisture fluxes through calculation of surface friction velocities and exchange coefficients. The Monin–Obukhov–Janjic (MOJ) scheme is one popular surface layer option in WRF. This is one of the schemes in WRF we choose to expedite toward an end-to-end accelerated weather model. One advantageous aspect in WRF is the independence among grid points that facilitates programming implementations in parallel computation. We here present a parallel construction on the MOJ module with application of vectorization elements and efficient parallelization essentials furnished by Intel many integrated core (MIC) architecture. To achieve high computing performance, apart from the fundamental usage of Intel MIC architecture, this paper offers some new approaches related to code structure and art of optimization skills. At the end, in comparison with the original code separately executing on one CPU core and on one CPU socket (eight cores) with Intel Xeon E5-2670, the optimized MIC-based MOJ module running on Xeon Phi coprocessor 7120P ameliorates the computing performance by 9.6× and 1.5×, respectively. Auteurs: Melin Huang;Bormin Huang;Hung-Lung Allen Huang; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4399 - 4408 Editeur: IEEE Document complet vers site de l'éditeur
» Accuracy of Range-Based Cooperative Positioning: A Lower Bound Analysis
 Résumé:Accurate location information is essential for mobile systems such as wireless sensor networks. A location-aware sensor network generally includes two types of nodes: Sensors whose locations to be determined and anchors whose locations are known a priori. For range-based cooperative positioning, sensors’ locations are deduced from anchor-to-sensor and sensor-to-sensor range measurements. Positioning accuracy depends on the network parameters such as network connectivity and size. This paper provides a generalized theory that quantitatively characterizes such a relation between network parameters and positioning accuracy. We use the average degree as a connectivity metric and use geometric dilution of precision (DOP) to quantify positioning accuracy. Under the assumption that nodes are randomly deployed, we prove a novel lower bound on expectation of average geometric DOP (LB-E-AGDOP) and derives a closed-form formula that relates LB-E-AGDOP to only three parameters: Average anchor degree, average sensor degree, and number of sensor nodes. The formula shows that positioning accuracy is approximately inversely proportional to the average degree, and a higher ratio of average anchor degree to average sensor degree yields better positioning accuracy. Furthermore, the paper shows a strong connection between LB-E-AGDOP and the best achievable accuracy. Finally, we demonstrate the theory via numerical simulations with three different random graph models. Auteurs: Liang Heng;Grace Xingxin Gao; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2304 - 2316 Editeur: IEEE Document complet vers site de l'éditeur
» Accuracy-Aware Power Management for Many-Core Systems Running Error-Resilient Applications
 Résumé:Power capping techniques based on dynamic voltage and frequency scaling (DVFS) and power gating (PG) are oriented toward power actuation, compromising on performance and energy. Inherent error resilience of emerging application domains, such as Internet-of-Things (IoT) and machine learning, provides opportunities for energy and performance gains. Leveraging accuracy-performance tradeoffs in such applications, we propose approximation (APPX) as another knob for close-looped power management, to complement power knobs with performance and energy gains. We design a power management framework, APPEND+, that can switch between accurate and approximate modes of execution subject to system throughput requirements. APPEND+ considers the sensitivity of the application to error to make disciplined alteration between levels of APPX such that performance is maximized while error is minimized. We implement a power management scheme that uses APPX, DVFS, and PG knobs hierarchically. We evaluated our proposed approach over machine learning and signal processing applications along with two case studies on IoT—early warning score system and fall detection. APPEND+ yields $1.9\times$ higher throughput, improved latency up to five times, better performance per energy, and dark silicon mitigation compared with the state-of-the-art power management techniques over a set of applications ranging from high to no error resilience. Auteurs: Anil Kanduri;Mohammad-Hashem Haghbayan;Amir M. Rahmani;Pasi Liljeberg;Axel Jantsch;Hannu Tenhunen;Nikil Dutt; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2749 - 2762 Editeur: IEEE Document complet vers site de l'éditeur
» Accuracy-Enhanced Algorithms for the Slot Leakage Inductance Computation of Double-Layer Windings
 Résumé:The paper presents original developments concerning the analytical computation of the slot leakage inductive parameters referring to unsaturated rotating electrical machines. In particular, the double-layer winding layout and arbitrary-shaped semi-closed slots are considered. The conventional analytical formulations of the self- and mutual-inductances of the two layers are initially presented, together with the algorithm developed for their computations. Then, the error causes laying on the simplifying assumptions are discussed and two corrections are applied to the conventional equations to enhance their accuracy with respect to finite element method estimations. Numerical examples of the magnetic energy stored in several slot geometrical domains are included in order to show the potentialities of the proposed analytical approach. Auteurs: Andrea Cavagnino; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4422 - 4430 Editeur: IEEE Document complet vers site de l'éditeur
» Accurate and Efficient Approximation of Clothoids Using Bézier Curves for Path Planning
 Résumé:An accurate and efficient clothoid approximation approach is presented in this paper using Bézier curves based on the minimization of curvature profile difference. Compared with existing methods, the proposed approach is able to guarantee higher order geometric continuity with smaller approximation error in terms of position, orientation, and curvature. The approximation scheme takes place in three stages. First, a subset of clothoids with specific winding angle constraints referred to as elementary clothoids is approximated using quintic Bézier curves. Then, a basic clothoid defined in the first quadrant is formulated, which is composed of a series of transformed elementary clothoids. An adaptive sampling stra-tegy is applied to ensure that the resulting Bézier segments are computed within a specified accuracy and all the required information can be obtained offline and stored in a lookup table. Finally, a general clothoid with arbitrary parameters can be conveniently approximated based on the lookup table through appropriate geometric transformations. A comparison with the recent circular interpolation and rational Bézier curve based approximation shows that the proposed approach is able to achieve equivalent or greater computational efficiency in most scenarios. Auteurs: Yong Chen;Yiyu Cai;Jianmin Zheng;Daniel Thalmann; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1242 - 1247 Editeur: IEEE Document complet vers site de l'éditeur
» Accurate Closed-Form Expressions for the Bit Rate-Wireless Transmission Distance Relationship in IR-UWBoF Systems
 Résumé:Efficient utilization of the extremely limited available power of impulse radio ultrawideband (IR-UWB) waveforms can significantly extend their wireless reach in the wireless transmission chain of IR-UWB over fiber (IR-UWBoF) systems. In this letter, the two most common types of photonically generated IR-UWB waveforms are considered and accurate closed-form analytical expressions for the bit rate—distance relationship in the wireless transmission chain of IR-UWBoF systems are developed. These analytical expressions are verified by simulations and optimized such that the wireless transmission distance of IR-UWB waveforms is maximized under the Federal Communications Commission spectral constraints. Auteurs: Mohamed Shehata;Hassan Mostafa;Yehea Ismail; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2138 - 2141 Editeur: IEEE Document complet vers site de l'éditeur
» Accurate Insect Orientation Extraction Based on Polarization Scattering Matrix Estimation
 Résumé:A novel insect orientation extraction method is proposed based on the target polarization scattering matrix (PSM) estimation, which is applicable for traditional vertical-looking insect radar with noncoherent reception as well as the coherent radar. The insect echo signal at different polarization directions on the radar polarization plane is usually acquired by means of rotating linearly polarized antenna. In this letter, the insect echo signal is first used to accurately estimate insect PSM by an iterative algorithm based on the second-order polynomial approximation. Meanwhile, the Cramer–Rao lower bound is also analyzed to test the estimation performance. Next, based on the assumption that the target orientation is consistent with the dominant eigenvector, the insect orientation is extracted from the estimated PSM. Finally, both theoretical simulations and real experimental data are used to validate the effectiveness and feasibility of our proposed method, which can achieve good orientation estimation accuracy at low signal-to-noise ratio. Auteurs: C. Hu;W. Li;R. Wang;C. Liu;T. Zhang;W. Li; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1755 - 1759 Editeur: IEEE Document complet vers site de l'éditeur
» Accurate Reduced Dimensional Polynomial Chaos for Efficient Uncertainty Quantification of Microwave/RF Networks
 Résumé:This paper presents a polynomial chaos (PC) formulation based on the concept of dimension reduction for the efficient uncertainty analysis of microwave and RF networks. This formulation exploits a high-dimensional model representation for quantifying the relative effect of each random dimension on the network responses surface. This information acts as problem-dependent sensitivity indices guiding the intelligent identification and subsequent pruning of the statistically unimportant random dimensions from the original parametric space. Performing a PC expansion in the resultant low-dimensional random subspace leads to the recovery of a sparser set of coefficients than that obtained from the full-dimensional random space with negligible loss in accuracy. Novel methodologies to reuse the preliminary PC bases and SPICE simulations required to estimate the sensitivity indices are presented, thereby making the proposed approach more efficient and accurate than standard sparse PC approaches. The validity of the proposed approach is demonstrated using three distributed network examples. Auteurs: Aditi Krishna Prasad;Sourajeet Roy; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3697 - 3708 Editeur: IEEE Document complet vers site de l'éditeur
» Accurate Solution of Electromagnetic Scattering by Super-Thin Conducting Objects Based on Magnetic Field Integral Equation
 Résumé:Electromagnetic scattering by super-thin conducting objects is formulated by integral equation approach. It could be difficult to obtain accurate solutions for such a problem because the current density changes dramatically near the edges of such objects and many low-quality meshes exist on the side faces of objects when discretized. Traditionally, the electric field integral equation is used to describe the problem and the three-dimensional (3-D) objects are approximated as a two-dimensional (2-D) open structure with a summation of the current density at two opposite sides. In this communication, the magnetic field integral equation (MFIE) is employed to govern the problem and the super-thin objects are strictly treated as 3-D objects. The MFIE is a second-kind integral equation resulting in a better conditioning and can also release the low-frequency breakdown problem, but it has not been applied to very thin structures. In the method of moments solution, a robust near-singularity treatment for its kernel is developed based on the Green’s lemma. The derived formulations are friendly and very suitable for low-quality triangular meshes. Numerical examples are presented to demonstrate the scheme and good results have been obtained. Auteurs: Mei Song Tong;Xiao Jia Huang; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5633 - 5638 Editeur: IEEE Document complet vers site de l'éditeur
» Achievable DoF Regions of MIMO Networks With Imperfect CSIT
 Résumé:We focus on a two-receiver multiple-input-multiple-output (MIMO), broadcast channel (BC), and interference channel (IC) with an arbitrary number of antennas at each node. We assume an imperfect knowledge of local channel state information at the transmitters, whose error decays with the signal-to-noise-ratio. With such configuration, we characterize the achievable degrees-of-freedom (DoF) regions in both BC and IC, by proposing a rate-splitting (RS) approach, which divides each receiver’s message into a common part and a private part. Compared with the RS scheme designed for the symmetric MIMO case, the novelties of the proposed block lie in: 1) delivering additional non-ZF-precoded private symbols to the receiver with the greater number of antennas and 2) a space-time implementation. These features provide more flexibilities in balancing the common-message-decodabilities at the two receivers, and fully exploit asymmetric antenna arrays. Besides, in IC, we modify the power allocation designed for the asymmetric BC based on the signal space, where the two transmitted signals interfere with each other. We also derive an outer-bound for the DoF regions and show that the proposed achievable DoF regions are optimal under some antenna configurations and channel state information at the transmitter side qualities. Auteurs: Chenxi Hao;Borzoo Rassouli;Bruno Clerckx; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6587 - 6606 Editeur: IEEE Document complet vers site de l'éditeur
» Acoustical Streaming in Microfluidic CMUT Integrated Chip Controls the Biochemical Interaction Rate
 Résumé:Acoustical fluid mixing and streaming in microfluidic chips enhance the detection and fluid routeing capabilities in the lab-on-chip devices. Capacitive micromachined ultrasound transducers (CMUT) are easy to integrate into a closely packed environment, and they can be simultaneously used as integrated sensors and micropumps/mixers. In this paper, particular focus is given to examininge the impact of the acoustical fluid mixing to the kinetics of biochemical interaction. CMUT interdigital transducers for 10-MHz operation in water were designed and fabricated using the surface micromachining technique. Devices use Scholte type waves for biochemical detection and acoustical streaming. They also have the ability to control the directionality of acoustical streaming by +/−90° phase shift. The impact of acoustical streaming to the liquid diffusion kinetics in the microchannel and to the kinetics of adsorption of the bovine serum albumin (BSA) to the gold surface was investigated experimentally. For microfluidic experiments, CMUTs were assembled with 100 $\mu \text{m}$ deep microchannels. It was determined that acoustical streaming can improve the diffusion rate through the microchannel. Also, it was shown that BSA adsorption rate can be controlled by changing the phase shift during excitation of the Sholte type waves. [2016–0224] Auteurs: Donatas Pelenis;Dovydas Barauskas;Evaldas Sapeliauskas;Gailius Vanagas;Marius Mikolajunas;Darius Virzonis; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1012 - 1017 Editeur: IEEE Document complet vers site de l'éditeur
» Active Disturbance Rejection Adaptive Control of Hydraulic Servo Systems
 Résumé:This paper presents an active disturbance rejection adaptive control scheme via full state feedback for motion control of hydraulic servo systems subjected to both parametric uncertainties and uncertain nonlinearities. The proposed controller is derived by effectively integrating adaptive control with extended state observer via backstepping method. The adaptive law is synthesized to handle parametric uncertainties and the remaining uncertainties are estimated by the extended state observer and then compensated in a feedforward way. The unique features of the proposed controller are that not only the matched uncertainties but also unmatched uncertainties are estimated by constructing two extended state observers, and the parameter adaptation law is driven by both tracking errors and state estimation errors. Since the majority of parametric uncertainties can be reduced by the parameter adaptation, the task of the extended state observer is much alleviated. Consequently, high-gain feedback is avoided and improved tracking performance can be expected. The proposed controller theoretically achieves an asymptotic tracking performance in the presence of parametric uncertainties and constant disturbances. In addition, prescribed transient tracking performance and final tracking accuracy can also be guaranteed when existing time-variant uncertain nonlinearities. Comparative experimental results are obtained to verify the high tracking performance nature of the proposed control strategy. Auteurs: Jianyong Yao;Wenxiang Deng; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8023 - 8032 Editeur: IEEE Document complet vers site de l'éditeur
» Active Disturbance Rejection Control of Linear Induction Motor
 Résumé:This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input–output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodeling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, the results have been compared with those achievable with the model-based feedback linearization control. Auteurs: Francesco Alonge;Maurizio Cirrincione;Filippo D’Ippolito;Marcello Pucci;Antonino Sferlazza; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4460 - 4471 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Auxiliary Particle Filter for Track-Before-Detect With Multiple Targets
 Résumé:A novel particle filter for multiple target tracking with track-before-detect measurement models is proposed. Particle filters efficiently perform target tracking under nonlinear or non-Gaussian models. However, their application to multiple target tracking suffers from the curse of dimensionality. We introduce an efficient particle filter for multiple target tracking which deals with the curse of dimensionality better than previously developed methods. The proposed algorithm is tested and compared to other multiple target tracking particle filters. Auteurs: Luis Úbeda-Medina;Ángel F. García-Fernández;Jesús Grajal; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2317 - 2330 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Backstepping Control for a Class of Nonlinear Systems With Non-Triangular Structural Uncertainties
 Résumé:In this technical note, a robust adaptive control scheme is proposed based on backstepping techniques for a class of nonlinear systems with unknown parameters. A modeling error may also exist in every state equation or channel and it is bounded by a known function which is allowed to depend on all system states. It is shown that the proposed adaptive control scheme can ensure all signals in the closed-loop system bounded, if the strength of system modeling errors is sufficiently weak. Transient performance is also established. Thus stabilizing systems in classical strict-feedback forms with sufficiently small non-triangular structural perturbations is successfully addressed. In the case that system parameters are known, a non-adaptive robust controller is designed to globally exponentially stabilize such a class of nonlinear systems. Finally simulation studies are used to verify the effectiveness of the proposed scheme. Auteurs: Jianping Cai;Changyun Wen;Hongye Su;Zhitao Liu;Lantao Xing; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5220 - 5226 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Computer-Aided Tuning of Coupled-Resonator Diplexers With Wire $T$ -Junction
 Résumé:This paper is devoted to theoretical and practical issues concerning computer-aided tuning (CAT) of coupled-resonator diplexers with tapped wire T-junction. Special attentions are paid to the following aspects: 1) finding an appropriate circuit model to represent the tapped wire T-junction; 2) developing a legitimate transformation strategy to obtain the coupling matrix of the right form corresponding to the topology of the diplexer containing a tapped wire T-junction; and 3) proposing an adaptive CAT scheme that takes stray couplings into account in a dynamically optimized target coupling matrix. A conventional combline diplexer and a helical resonator diplexer are used as examples to demonstrate the circuit model extraction procedure and the adaptive CAT concept, showing the effectiveness and robustness of the proposed adaptive CAT method for practical applications. Auteurs: Ping Zhao;Ke-Li Wu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3856 - 3865 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Driving Bus Voltage and Energy Recycling Control Schemes for Low-Power AC–DC RGB-LED Drivers
 Résumé:A low-power ac-dc light-emitting diode (LED) driver with adaptive driving bus voltage (ADBV) and energy recycling (ER) control schemes is proposed to drive red, green, and blue LEDs in series to achieve high efficiency. The bus voltage of the power factor correction flyback converter with the ADBV control is always adjusted, so as to reduce power loss on current regulators. However, since the small bandwidth of the flyback converter and large bus capacitor limit the transient response of the flyback converter, it is difficult to maintain the voltage across current regulators at the minimum value. The ER control is proposed to accelerate the transient response of the bus voltage, making the voltage across current regulators as close to the minimum voltage as possible. Furthermore, extra energy is stored and restored on the recycling capacitor when the bus voltage is switched between different supplying levels without consuming much power due to the ER control. The experimental waveforms of the laboratory prototype are shown to confirm the validity of the proposed schemes. Auteurs: Pang-Jung Liu;Kai-Lin Peng; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7741 - 7748 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Dynamic Surface Control for a Hypersonic Aircraft Using Neural Networks
 Résumé:A hypersonic aircraft dynamic model is highly nonlinear because its flight conditions are usually determined at high altitude and Mach number. Therefore, there always exist differences between the dynamical model and real system, and uncertainties during the flight, thus, leading significant degradation of control performance. To solve the performance degradation problem, this paper proposes neural networks-based adaptive velocity and altitude tracking controllers. In order for that, the hypersonic aircraft model is transformed into an uncertain feedback system, which has both matched and unmatched uncertainties, by differentiating the velocity and altitude with respect to time. Then, the overall tracking control system is designed systematically by introducing virtual control inputs and dynamic surface control. During the design process, an inverse of an input gain matrix is directly trained and adapted to remove the matched uncertainty and controller singularity problem simultaneously. In addition, several adaptive elements with saturation functions are added to handle all the matched and unmatched uncertainties. The proposed controller guarantees the uniformly ultimate boundedness of the tracking error by utilizing deadzoned errors. Finally, numerical simulations with the uncertain hypersonic aircraft are performed to demonstrate the effectiveness of the proposed approach. Auteurs: Jongho Shin; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2277 - 2289 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Eulerian Video Processing of Thermal Video: An Experimental Analysis
 Résumé:The use of spatiotemporal video processing to extract biosignals is an emerging technique. This paper aims to build upon current work through robust experimentation and analysis. A blood flow simulation model was captured by thermal and optical cameras, while hot water was pumped through the system. Additionally, five subjects were recruited to perform two experimental trials: a facial perfusion trial and an arm blood occlusion trial, for which subjects sat quietly, while video data were captured using thermal and optical cameras. Each video was subjected to region of interest selection and adaptive Eulerian video magnification (EVM); the iterative application of EVM, first with a wide temporal bandpass filter and low amplification factor and again with a narrower, targeted temporal bandpass filter and higher amplification factor. The results from the simulation experiments indicated that thermal video in conjunction with adaptive EVM processing can reveal variations in temperature indicative of pulse rate in a controlled system of known variables. This process helped to better characterize Eulerian signal enhancement versus Eulerian noise enhancement. The results from the facial perfusion experiments suggest that the adaptive EVM processing of thermal video results in signals representative of facial perfusion rate. The results from the blood occlusion experiments revealed an occlusion temperature pattern, but not a perfusion rate. This paper therefore further demonstrated the potential of thermal video in conjunction with adaptive EVM methods to extract a signal representative of facial perfusion rate, and illustrated the need for more research on thermal video and adaptive EVM. Auteurs: Stephanie Bennett;Tarek Nasser El Harake;Rafik Goubran;Frank Knoefel; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2516 - 2524 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Filtering Under a Variable Kernel Width Maximum Correntropy Criterion
 Résumé:The maximum correntropy criterion (MCC) algorithm with constant kernel width leads to a tradeoff problem in terms of convergence rate and steady-state misalignment. Thus, this brief proposes a variable kernel width (VKW) MCC algorithm to overcome this problem. The optimal kernel width of the proposed VKW-MCC algorithm is calculated at each iteration by maximizing ${{\rm exp}(-e_{k}^{2}/2\sigma _{k}^{2})}$ with respect to the kernel width ${ \sigma _{k}}$ , wherein the kernel width is a function of the error, to make the error with greatest attenuation along the direction of the gradient ascent. Simulations in the contexts of system identification and echo cancellation have demonstrated that the proposed VKW-MCC algorithm yields a superior performance. Auteurs: Fuyi Huang;Jiashu Zhang;Sheng Zhang; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1247 - 1251 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Fuzzy Asymptotic Control of MIMO Systems With Unknown Input Coefficients Via a Robust Nussbaum Gain-Based Approach
 Résumé:This paper proposes an adaptive fuzzy asymptotic control method for multiple input multiple output (MIMO) nonlinear systems with unknown input coefficients, with a focus on handling unknown input nonlinearities and control directions. For all the existing Nussbaum gain-based approaches, it is difficult to investigate unknown input coefficients problem since multiple time-varying coefficients and disturbances coexist and should be simultaneously tackled in the stability analysis. To overcome the above difficulty, we propose a robust Nussbaum gain-based approach for the adaptive fuzzy asymptotic control of MIMO nonlinear systems. Benefiting from the proposed Nussbaum gain-based approach, bounded disturbances including unmodeled system dynamics and universal approximation errors are handled. Furthermore, the proposed approach helps extend the bounded fuzzy control result to the asymptotic convergence. Hence, both the control robustness and control accuracy are prompted within the frame of the developed Nussbaum gain approach. Finally, a simulation example is carried out to illustrate the effectiveness of the proposed control method. Auteurs: Ci Chen;Zhi Liu;Kan Xie;Yanjun Liu;Yun Zhang;C. L. Philip Chen; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1252 - 1263 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Fuzzy Hierarchical Sliding-Mode Control for a Class of MIMO Nonlinear Time-Delay Systems With Input Saturation
 Résumé:In this paper, an adaptive fuzzy hierarchical sliding-mode control method for a class of multiinput multioutput unknown nonlinear time-delay systems with input saturation is proposed. The studied system is first transformed into an equivalent system. Subsequently, based on sliding-mode control technology and the concept of hierarchical design, a set of adaptive fuzzy hierarchical sliding-mode controllers are designed for the new defined system by using fuzzy systems to approximate uncertain functions and compensate input saturation. Choosing an appropriate Lyapunov–Krasovskii function, it is theoretically proved that all the signals in the closed-loop system together with the proposed sliding surfaces are uniformly ultimately bounded under our designed adaptive fuzzy controllers. Simulation results demonstrate the effectiveness of the proposed design techniques for the systems under consideration. Auteurs: Xudong Zhao;Haijiao Yang;Weiguo Xia;Xinyong Wang; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1062 - 1077 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Group Shuffled Decoding for LDPC Codes
 Résumé:We propose new grouping methods for group shuffled (GS) decoding of both regular and irregular low-density parity check cods. These methods are applicable for the belief-propagation as well as the min-sum-based GS decoders. Integer-valued metrics for measuring the reliability of each tentative variable node (VN) decision and the associated likelihood of being corrected are developed. The metrics are used to determine the VN updating priority, so the grouping may vary in each iteration. We estimate the computation complexity needed to adaptively regroup VNs. Numerical results show that our GS algorithms improve the performance of some existing GS belief-propagation decoders. Auteurs: Tofar C.-Y. Chang;Yu T. Su; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2118 - 2121 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Impedance Control of Human–Robot Cooperation Using Reinforcement Learning
 Résumé:This paper presents human-robot cooperation with adaptive behavior of the robot, which helps the human operator to perform the cooperative task and optimizes its performance. A novel adaptive impedance control is proposed for the robotic manipulator, whose end-effector's motions are constrained by human arm motion limits. In order to minimized motion tracking errors and acquire an optimal impedance mode of human arms, the linear quadratic regulation (LQR) is formulated; then, integral reinforcement learning (IRL) has been proposed to solve the given LQR with little information of the human arm model. Considering human-robot interaction force during the robot performing manipulation, a novel barrier-Lyapunov-function-based adaptive impedance control incorporating adaptive parameter learning is developed for physical limits, transient perturbations, and time-varying dynamics. Experimental results validate that the proposed controller is effective in assisting the operator to perform the human-robot cooperative task. Auteurs: Zhijun Li;Junqiang Liu;Zhicong Huang;Yan Peng;Huayan Pu;Liang Ding; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8013 - 8022 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Inverse Control for Gripper Rotating System in Heavy-Duty Manipulators With Unknown Dead Zones
 Résumé:The gripper rotation system of a heavy-duty manipulator is generally driven by hydraulic motors, and it is difficult to guarantee the accuracy of the rotation angle using conventional control methods due to the existence of dead zones with unknown characteristics. This paper proposes an adaptive inverse dead-zone control method, in which the gradient projection technique is applied to design an adaptive updating law for estimating the inverse dead-zone parameters online. First, a dynamic model of the gripper rotation system is presented with an analysis of its dead-zone characteristics. Then, the controller is designed based on a Takagi-Sugeno fuzzy model, and the estimated values of the inverse dead-zone parameters are shown to converge to their true values. Finally, the performance of the proposed adaptive control method is experimentally demonstrated on an actual forging manipulator. Comparisons with a fixed inverse dead-zone control method demonstrate the effectiveness and applicability of the proposed control method. Auteurs: Hua Deng;Jiehua Luo;Xiaogang Duan;Guoliang Zhong; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7952 - 7961 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Multimedia Data Forwarding for Privacy Preservation in Vehicular Ad-Hoc Networks
 Résumé:Vehicular ad-hoc networks (VANETs) have drawn much attention of researchers. The vehicles in VANETs frequently join and leave the networks, and therefore restructure the network dynamically and automatically. Forwarded messages in vehicular ad-hoc networks are primarily multimedia data, including structured data, plain text, sound, and video, which require access control with efficient privacy preservation. Ciphertext-policy attribute-based encryption (CP-ABE) is adopted to meet the requirements. However, solutions based on traditional CP-ABE suffer from challenges of the limited computational resources on-board units equipped in the vehicles, especially for the complex policies of encryption and decryption. In this paper, we propose a CP-ABE delegation scheme, which allows road side units (RSUs) to perform most of the computation, for the purpose of improving the decryption efficiency of the vehicles. By using decision tree to jointly optimize multiple factors, such as the distance from RSU, the communication and computational cost, the CP-ABE delegation scheme is adaptively activated based on the estimation of various vehicles decryption overhead. Experimental results thoroughly demonstrate that our scheme is effective and efficient for multimedia data forwarding in vehicular ad-hoc networks with privacy preservation. Auteurs: Yingjie Xia;Wenzhi Chen;Xuejiao Liu;Luming Zhang;Xuelong Li;Yang Xiang; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2629 - 2641 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Nonlocal Sparse Representation for Dual-Camera Compressive Hyperspectral Imaging
 Résumé:Leveraging the compressive sensing (CS) theory, coded aperture snapshot spectral imaging (CASSI) provides an efficient solution to recover 3D hyperspectral data from a 2D measurement. The dual-camera design of CASSI, by adding an uncoded panchromatic measurement, enhances the reconstruction fidelity while maintaining the snapshot advantage. In this paper, we propose an adaptive nonlocal sparse representation (ANSR) model to boost the performance of dual-camera compressive hyperspectral imaging (DCCHI). Specifically, the CS reconstruction problem is formulated as a 3D cube based sparse representation to make full use of the nonlocal similarity in both the spatial and spectral domains. Our key observation is that, the panchromatic image, besides playing the role of direct measurement, can be further exploited to help the nonlocal similarity estimation. Therefore, we design a joint similarity metric by adaptively combining the internal similarity within the reconstructed hyperspectral image and the external similarity within the panchromatic image. In this way, the fidelity of CS reconstruction is greatly enhanced. Both simulation and hardware experimental results show significant improvement of the proposed method over the state-of-the-art. Auteurs: Lizhi Wang;Zhiwei Xiong;Guangming Shi;Feng Wu;Wenjun Zeng; Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence Date publication: 10.-2017, volume: 39, issue:10, pages: 2104 - 2111 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive OFDM Integrated Radar and Communications Waveform Design Based on Information Theory
 Résumé:To improve the effectiveness of limited spectral resources, an adaptive orthogonal frequency division multiplexing integrated radar and communications waveform design method is proposed. First, the conditional mutual information (MI) between the random target impulse response and the received signal, and the data information rate (DIR) of frequency selective fading channel are formulated. Then, with the constraint on the total power, the optimization problem, which simultaneously considers the conditional MI for radar and DIR for communications, is devised, and the analytic solution is derived. With low transmit power, the designed integrated waveform outperforms the fixed waveform (i.e., equal power allocation). Finally, several simulated experiments are provided to verify the effectiveness of the designed waveform. Auteurs: Yongjun Liu;Guisheng Liao;Jingwei Xu;Zhiwei Yang;Yuhong Zhang; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2174 - 2177 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Out-of-Band Interference Suppression for Coexistent Wi-Fi and Bluetooth Systems
 Résumé:Coexistence of Wi-Fi and Bluetooth (BT) systems is often necessary in various handheld devices. Due to nonlinearities of radio frequency front-end components, leakage signals from one transmitter to the other transmitter would produce out-of-band (OOB) interference and corrupt adjacent frequency bands outside the spectral masks defined in standards. In this letter, we propose an adaptive OOB interference suppression scheme based on a modified normalized least mean-squared algorithm for coexistent Wi-Fi and BT transceivers. Computer simulation results show that the proposed approach provides pretty good performance in transmitter leakage cancellation and effectively relieves the OOB interference issue. Auteurs: Chin-Liang Wang;Min-Chau Jan;Yuan-Shuo Chang;Erlang Wang;Ying-Hsi Lin; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2306 - 2309 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Particle Swarm Optimization with Heterogeneous Multicore Parallelism and GPU Acceleration
 Résumé:Much progress has recently been made in global optimization, with particular attention devoted to robust nature-inspired stochastic methods for difficult, high-dimensional problems. This paper presents a computational study of an adaptation of one such method, particle swarm optimization (PSO), which is analyzed for parallelization on readily-available heterogeneous parallel computational hardware: specifically, multicore technologies accelerated by graphics processing units (GPUs), as well as Intel Xeon Phi co-processors accelerated with vectorization. In this heterogeneous approach, computationally-intensive, task-parallel components are performed with multicore parallelism and data-parallel elements are executed via co-processing (GPUs or vectorization). A computationally intensive adaptive PSO technique is parallelized according to this schema. In experiments with two high-dimensional and complex functions, large speedups can be obtained. Thus, a heterogeneous approach mitigates the time complexity of PSO adaptations, suggesting that other time-intensive stochastic methods can also benefit from the techniques proposed here. Auteurs: Mark P. Wachowiak;Mitchell C. Timson;David J. DuVal; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2784 - 2793 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:Weather radar commonly uses a matched filter (MF) method to improve the range resolution and signal-to-noise ratio. A X-band phased array weather radar (PAWR), which is capable of 3-D precipitation observations in less than 30 s, is in operation at the Osaka University. The PAWR uses the MF method. In weather radar systems, the magnitude of the range sidelobes is an important topic because it can cause overestimation of the received power from a target, such as precipitation or ground clutter echoes. We propose a minimum mean square error (MMSE)-based pulse compression method to reduce the range sidelobes of the PAWR. We evaluated an MF, an MF with a raised-cosine window, and MMSE methods using numerical simulations and actual measurement data obtained from the PAWR. The results show that the MMSE method is clearly superior to the MF and MF with a raised-cosine filter methods when considering the reduction in the range sidelobes. Auteurs: H. Kikuchi;E. Yoshikawa;T. Ushio;F. Mizutani;M. Wada; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1810 - 1814 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Search Range for HEVC Motion Estimation Based on Depth Information
 Résumé:High Efficiency Video Coding achieves twofold coding efficiency improvement compared with its predecessor H.264/MPEG-4 Advanced Video Coding. However, it suffers from high computational complexity due to its quad-tree structure in motion estimation (ME). This paper exposes the use of depth maps in the multiview video plus depth format for relieving the computational burden. The depth map provides an intimation of the objects’ distance from the projected screen in a 3D scene, which is explored in adaptive search range determination in this paper. The proposed algorithm exploits the high temporal correlation between the depth map and the motion in texture. By utilizing this correlation, a depth/motion relationship map is built for a mapping process. For each block, this forms a tailor-made search range with a motion-aware asymmetric shape to skip unnecessary search points in ME. The obtained search range can be further adjusted by taking the influence of 3D-to-2D projection into consideration. Simulation results reveal that, compared to the full search approach, the proposed algorithm can reduce the complexity by 93% on average, whereas the coding efficiency can be maintained. Besides, the proposed search range determination can work well with other fast search ME algorithms in the literature. Auteurs: Tsz-Kwan Lee;Yui-Lam Chan;Wan-Chi Siu; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2216 - 2230 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:In this letter, an adaptive spatial modulation (SM) scheme, in which the spatial signatures of the transmitted signals are adaptively selected according to the channel responses, is proposed for the uplink of a millimeter-wave communication system. We first use an iterative method to search for the spatial signatures that maximize the minimum Euclidean distance of the SM symbols. Following this, a suboptimal scheme is provided to reduce the computational complexity. Numerical results show that the proposed adaptive SM scheme can effectively reduce the system symbol-error rate. Auteurs: Sheng Luo;Xuan Tuong Tran;Kah Chan Teh;Kwok Hung Li; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2178 - 2181 Editeur: IEEE Document complet vers site de l'éditeur
» Adaptive Video Streaming With Network Coding Enabled Named Data Networking
 Résumé:The fast and huge increase of Internet traffic motivates the development of new communication methods that can deal with the growing volume of data traffic. To this aim, named data networking (NDN) has been proposed as a future Internet architecture that enables ubiquitous in-network caching and naturally supports multipath data delivery. Particular attention has been given to using dynamic adaptive streaming over HTTP to enable video streaming in NDN as in both schemes data transmission is triggered and controlled by the clients. However, state-of-the-art works do not consider the multipath capabilities of NDN and the potential improvements that multipath communication brings, such as increased throughput and reliability, which are fundamental for video streaming systems. In this paper, we present a novel architecture for dynamic adaptive streaming over network coding enabled NDN. In comparison to previous works proposing dynamic adaptive streaming over NDN, our architecture exploits network coding to efficiently use the multiple paths connecting the clients to the sources. Moreover, our architecture enables efficient multisource video streaming and improves resiliency to Data packet losses. The experimental evaluation shows that our architecture leads to reduced data traffic load on the sources, increased cache-hit rate at the in-network caches and faster adaptation of the requested video quality by the clients. The performance gains are verified through simulations in a Netflix-like scenario. Auteurs: Jonnahtan Saltarin;Eirina Bourtsoulatze;Nikolaos Thomos;Torsten Braun; Apparue dans: IEEE Transactions on Multimedia Date publication: 10.-2017, volume: 19, issue:10, pages: 2182 - 2196 Editeur: IEEE Document complet vers site de l'éditeur
» Adjustable Microwave Magnetic Spectra of Metamaterials Based on Ferromagnetic Film Laminates
 Résumé:A resonant RLC circuit with a magnetic core has been investigated experimentally and theoretically as a promising metamaterial cell design. Laminates of multilayer ferromagnetic films serve as a magnetic core. The ferromagnetic resonance frequency of the bare laminate core is above 1 GHz. An intensive magnetic absorption peak is obtainable at lower frequencies due to a resonant wire coiled around the core. Such magnetic metamaterials seem promising for applications that require high magnetic loss at frequencies of hundreds of megahertz. This paper focuses on efficient approaches to adjusting the location of magnetic loss peak in magnetic metamaterials. High-frequency permeability of the metamaterial samples has been measured in a rectangular waveguide. It is shown that by varying the geometry, structure, and composition of the measured metamaterial samples, the magnetic spectra can be radically changed. Excitation of electromagnetic resonance in the ferromagnetic core with the resonant wire is discussed within the frame of the quasi-static approximation. Auteurs: S. Y. Bobrovskii;I. T. Iakubov;A. N. Lagarkov;A. V. Osipov;K. N. Rozanov; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 6 Editeur: IEEE Document complet vers site de l'éditeur
» ADMM $\supseteq$ Projective Dynamics: Fast Simulation of Hyperelastic Models with Dynamic Constraints
 Résumé:We apply the alternating direction method of multipliers (ADMM) optimization algorithm to implicit time integration of elastic bodies, and show that the resulting method closely relates to the recently proposed projective dynamics algorithm. However, as ADMM is a general purpose optimization algorithm applicable to a broad range of objective functions, it permits the use of nonlinear constitutive models and hard constraints while retaining the speed, parallelizability, and robustness of projective dynamics. We further extend the algorithm to improve the handling of dynamically changing constraints such as sliding and contact, while maintaining the benefits of a constant, prefactored system matrix. We demonstrate the benefits of our algorithm on several examples that include cloth, collisions, and volumetric deformable bodies with nonlinear elasticity and skin sliding effects. Auteurs: Matthew Overby;George E. Brown;Jie Li;Rahul Narain; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2222 - 2234 Editeur: IEEE Document complet vers site de l'éditeur
» Advanced Fast 3-D Electromagnetic Solver for Microwave Tomography Imaging
 Résumé:This paper describes a fast-forward electromagnetic solver (FFS) for the image reconstruction algorithm of our microwave tomography system. Our apparatus is a preclinical prototype of a biomedical imaging system, designed for the purpose of early breast cancer detection. It operates in the 3–6-GHz frequency band using a circular array of probe antennas immersed in a matching liquid; it produces image reconstructions of the permittivity and conductivity profiles of the breast under examination. Our reconstruction algorithm solves the electromagnetic (EM) inverse problem and takes into account the real EM properties of the probe antenna array as well as the influence of the patient’s body and that of the upper metal screen sheet. This FFS algorithm is much faster than conventional EM simulation solvers. In comparison, in the same PC, the CST solver takes ~45 min, while the FFS takes ~1 s of effective simulation time for the same EM model of a numerical breast phantom. Auteurs: Nikolai Simonov;Bo-Ra Kim;Kwang-Jae Lee;Soon-Ik Jeon;Seong-Ho Son; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 10.-2017, volume: 36, issue:10, pages: 2160 - 2170 Editeur: IEEE Document complet vers site de l'éditeur
» Advanced Synchronizing Systems for Offshore Power Systems: Improving System Reliability and Flexibility
 Résumé:Small power systems, such as those found on offshore platforms, are fragile, yet they must operate reliably for economy and the safety of both personnel and the environment. These systems often include combustion turbine generators for the main process power requirements and black start diesel generators that can supply essential and emergency buses; the diesel generators can also be used to restart the main generation systems in the event of a power-system collapse. The power distribution systems on these offshore platforms have built-in redundancy with multiple circuits to supply critical loads for fault tolerance and operating flexibility. A system to easily and safely synchronize islanded buses via many possible synchronization points can revolutionize the operational flexibility and, therefore, the safety and reliability of the power system. This article reports on advanced synchronizing systems installed on two offshore platforms. Auteurs: Michael J. Thompson;Allen Li;Roy Luo;Michael C. Tu;Iris Urdaneta; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 60 - 69 Editeur: IEEE Document complet vers site de l'éditeur
» Advances in Magnetics Epitaxial Multiferroic Heterostructures and Applications
 Résumé:The ever increasing demand for ultralow power electronics has propelled the exploration of novel multiferroics for realizing voltage control of magnetism in an energy efficient manner. Epitaxial multiferroic heterostructures, possessing a strong lattice-coupled mechanical interface and allowing an electric field (E-field) significantly modulating spin, charge, lattice, and orbital order parameters, have drawn much attention for creating novel magnetoelectric (ME) coupling effects. In this paper, we review the recent progress on control of ME properties in epitaxial multiferroic heterostructures, including their novel physical properties, various strong interfacial ME interactions, and potential applications. Meanwhile, the essential interfacial couplings, allowing cross-tuning of lattice and charge-coupled parameters, have been extensively reviewed. Electric tuning of magnetism in epitaxial multiferroic heterostructures provides a great platform to develop lightweight, compact, and energy-efficient spintronic or electronic devices. Auteurs: Mingmin Zhu;Tianxiang Nan;Bin Peng;Yijun Zhang;Ziyao Zhou;Xi Yang;Wei Ren;Nian X. Sun;Ming Liu; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 16 Editeur: IEEE Document complet vers site de l'éditeur
» Aggregating LTE and Wi-Fi: Toward Intra-Cell Fairness and High TCP Performance
 Résumé:The data explosion and resource scarcity of mobile cellular networks require new paradigms to effectively integrate heterogeneous radio resources. Of many candidate approaches, smart aggregation of LTE and Wi-Fi radios is a promising solution that bonds heterogeneous links to meet a mobile terminal’s bandwidth need. Motivated by the existence of a significant number of carrier operated Wi-Fi APs, we propose an easily deployable mechanism, called LTE-W, which efficiently utilizes LTE and Wi-Fi links only with the minimum change of eNodeBs, LTE backhaul networks, and mobile terminals. LTE-W, which is a link-level aggregation mechanism, has the following two key components: 1) mode selection and 2) bearer-split scheduling. First, in the mode selection, LTE-W internally decides who should be served by either LTE-only or LTE-Wi-Fi aggregation considering intra-cell fairness rather than just following users’ intention of aggregation. For the users’ preference to be offered the aggregation service, we choose a bearer (roughly defined in LTE as a set of flows with a similar QoS) as a basic unit of aggregation and propose a smart intra-bearer scheduling algorithm that splits a bearer’s traffic into LTE and Wi-Fi links, considering the performance of TCP flows that take two heterogeneous wireless links. We evaluate our mechanism using the NS-3 with LENA, under various configurations, including nodes with mobility and HTTP traffic, and compare it with a transport-level aggregation mechanism, multipath TCP (MPTCP), demonstrating that LTE-W significantly improves MPTCP, e.g., up to 75% in terms of Jain’s fairness index. Auteurs: Boram Jin;Segi Kim;Donggyu Yun;Hojin Lee;Wooseong Kim;Yung Yi; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6295 - 6308 Editeur: IEEE Document complet vers site de l'éditeur
» Albedo Retrieval From Multispectral Landsat 8 Observation in Urban Environment: Algorithm Validation by in situ Measurements
 Résumé:The surface albedo in urban environment represents one of the most influencing parameters in the formation of the Urban Heat Island (UHI). Its assessment is therefore strategic to undertake actions for the UHI mitigation: the increase of urban surface reflectivity is an example of cooling strategies increasingly proposed and developed. Spaceborne observations could give a significant contribution supplying albedo maps, and different retrieval algorithms estimating broadband albedo from narrow band reflectivities provided by satellite sensors were proposed and validated in literature. In this study, the accuracy of two well-known retrieval algorithms applied to Landsat 8 OLI reflectivities was assessed in a city of Central Italy (Perugia), selecting test sites having different land cover types. Since the root mean square error of the estimated albedo was quite high (0.07–0.08), a custom retrieval algorithm was developed to evaluate the potential improvement in the narrowband reflectivity-broadband albedo conversion for the case study. This analysis was made possible thanks to an in situ measurement campaign, carried out during the summer months of 2016. The selected sites, having quite homogenous features inside the urban environment, also demonstrated that the albedo values are not significantly affected by the hour of the day, if measurements are taken near noon (variation less than 7%). Spaceborne observations showed once again a powerful tool for monitoring large areas with a quite good spatial resolution (30 m), even if an improvement of the literature albedo retrieval algorithms is required and possible in an urban context. Auteurs: Giorgio Baldinelli;Stefania Bonafoni;Antonella Rotili; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4504 - 4511 Editeur: IEEE Document complet vers site de l'éditeur
» Algorithms for Accurate Spectral Analysis in the Presence of Arbitrary Noncoherency and Large Distortion
 Résumé:In spectral analysis, achieving coherent sampling, especially when signals have large distortion, has been a challenge for many years. This paper introduces three algorithms to resolve this issue. In comparison to previous algorithms, and two widely used methods in industry: windowing and four-parameter sine wave fit, these new algorithms are capable of obtaining accurate spectral results of the signal, while achieving high accuracy as well as computational efficiency. The novel contribution of this paper is that not only does it propose two new algorithms, but also it analyzes their advantages and limitations in detail, providing their trade-offs and different fields of applications. Extensive simulations and measurements are performed to validate these algorithms. Combined with their high accuracy, computational efficiency, and robustness against signal purity, these algorithms are readily available to be implemented for bench or on-chip testing. In addition, it is suitable for data converter spectral testing when noncoherent sampling is present, and spectrally pure test signal source is not available. Auteurs: Yuming Zhuang;Degang Chen; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2556 - 2565 Editeur: IEEE Document complet vers site de l'éditeur
» Aligned Reverse Frame Structure for Interference Mitigation in Dynamic TDD Systems
 Résumé:The dynamic time division duplex (TDD) system has been proposed as a way to meet today’s asymmetrically and dynamically changing traffic demand. However, this approach causes cross-link interference, because neighboring base stations and user elements transmit in opposite directions. In this paper, we investigate and analyze the characteristics of cross-link interference in dynamic TDD systems. Based on this observation, we propose an aligned reverse frame structure to utilize and cancel the cross-link interference. Mathematical analysis and numerical results verify that the proposed scheme achieves performance enhancement in terms of capacity compared with conventional dynamic TDD systems. Auteurs: Kwonjong Lee;Yosub Park;Minsoo Na;Hanho Wang;Daesik Hong; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6967 - 6978 Editeur: IEEE Document complet vers site de l'éditeur
» All-Fiber-Optics-Based Microwave Photonic Filter With Tunable Center Frequency and Passband Plus Notch
 Résumé:We propose and demonstrate a microwave photonic band-pass filter (MPF), which features a single light source, with continuously and independently tunable center frequency and bandwidth. The center frequency and bandwidth can be adjusted by tuning the variable optical delay line and the position of a spatial filter, respectively. Using a balanced photodetector, the baseband, which is ineradicable in some conventional designs, and the common-mode noise are canceled in our proof-of-concept experiment. Alternatively, a notch with continuously tunable frequency can also be added in the MPF. The experimental measurements of the frequency response of this MPF are demonstrated, which have a good agreement with the theoretical simulations. Auteurs: Xiao Zhang;Chengming Wang;Wenchao Liao;Wenxin Zhang;Shengnan Ai;Zhangkai Peng;Ping Xue; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» All-Optical Actively Mode-Locked Fiber Laser at 2-μm Based on Interband Modulation
 Résumé:In this paper, we have achieved a high repetition rate and tunable pulse generation near ∼2 μm through an all-optical actively mode-locked fiber laser. The performances of the fiber laser have been systematically investigated through numerical simulations. The thulium-doped fiber laser cavity is modulated by the optical injection at 1.55 μm via a nonlinear optical loop mirror in which a specially-designed group-velocity-matching highly nonlinear fiber is incorporated. According to the simulation results, up to 40-GHz pulse train with picosecond tunable pulse width and peak power can be produced. Moreover, the repetition rate can be further enlarged with the help of higher gain. The impacts of gain coefficient, cavity length, and repetition rate on the output are studied in details. The proposed mode-locked fiber laser can be potentially used for future 2- μm fiber communication. Auteurs: Xu Wu;Zhichao Wu;Tianye Huang;Bingwei Chen;Kaixuan Ren;Songnian Fu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» All-Optical Intensity Modulator by Polarization-Dependent Graphene-Microfiber Waveguide
 Résumé:We demonstrated all-optical intensity modulator based on polarization-dependent graphene-covered microfiber (GMF) waveguide. By controlling the polarization mode of incident light, a greatly adjustable enhanced interaction between the propagating light and the graphene can be obtained via the evanescent field of the microfiber. By employing 980-nm pump light and 1550-nm signal light in continuous wave, the strong light–graphene interaction enables a maximum modulation depth of ∼20.86 dB, and by pumping 980 nm wave pulses, we obtained the temporal response characteristics of signal light with modulation rate of 5.13 kHz. This all-optical intensity modulator is compatible with optical fiber systems, and features with ease of fabrication, and steerable high modulation depth, which show potential in graphene's applications such as all-optical switching and all-optical communications. Auteurs: Ruiduo Wang;Diao Li;Hao Wu;Man Jiang;Zhipei Sun;Yonghui Tian;Jintao Bai;Zhaoyu Ren; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» An Accurate and Fast Converging Short-Term Load Forecasting Model for Industrial Applications in a Smart Grid
 Résumé:Short-term load forecasting (STLF) models are very important for electric industry in the trade of energy. These models have many applications in the day-to-day operations of electric utilities such as energy generation planning, load switching, energy purchasing, infrastructure maintenance, and contract evaluation. A large variety of STLF models have been developed that trade off between forecast accuracy and convergence rate. This paper presents an accurate and fast converging STLF model for industrial applications in a smart grid. In order to improve the forecast accuracy, modifications are devised in two popular techniques: mutual information based feature selection; and enhanced differential evolution algorithm based error minimization. On the other hand, the convergence rate of the overall forecast strategy is enhanced by devising modifications in the heuristic algorithm and in the training process of the artificial neural network. Simulation results show that accuracy of the newly proposed forecast model is 99.5% with moderate execution time, i.e., we have decreased the average execution of the existing bilevel forecast strategy by 52.38%. Auteurs: Ashfaq Ahmad;Nadeem Javaid;Mohsen Guizani;Nabil Alrajeh;Zahoor Ali Khan; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2587 - 2596 Editeur: IEEE Document complet vers site de l'éditeur
» An Accurate Method for MPPT to Detect the Partial Shading Occurrence in a PV System
 Résumé:This paper proposes an accurate detection scheme that effectively differentiates the partial shading from the uniform change of irradiance. By doing so, it avoids the unnecessary global peak search which results in a drop of the maximum power point tracker (MPPT) efficiency. The detection is achieved by calculating the irradiance at two designated points on the I–V curve namely, i.e., the short-circuit $(I_{{\text{sc}}})$ and MPP $(I_{{\text{mpp}}})$ currents. Since the mismatch of irradiance at these two points differs greatly for the partial shading and uniform irradiance change, the occurrence of the former is easily discriminated. To prove its effectiveness, the scheme is integrated into perturb and observe and particle swarm optimization MPPT algorithms using a buck–boost converter. Its performance under several partial shading and dynamic shading condition is simulated using MATLAB/Simulink and validated using the dSpace DS1104 platform. It only requires three samples to determine if partial shading occurs; without the scheme, an unnecessary scans of the entire P–V curve is initiated. Consequently, MPPT transient efficiency is increased by 30–35%. In addition to this, the calculated irradiance is utilized to update the open-circuit voltage of the array, thus eliminating the use of temperature and irradiance sensors. Auteurs: Jubaer Ahmed;Zainal Salam; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2151 - 2161 Editeur: IEEE Document complet vers site de l'éditeur
» An Accurate Representation of Incoherent Layers Within One-Dimensional Thin-Film Multilayer Structures With Equivalent Propagation Matrices
 Résumé:We propose a novel approach of including incoherent layers into an arbitrary multilayer stack and treating them using the conventional matrix methods in the wave-optics regime. The proposed “Equivalent Matrix Method” (EMM) calculates two phase-shift additions that totally cancel out the interference terms in front of, and behind the incoherent layer. The additions are merged into an equivalent incoherent layer propagation matrix that can be used in the standard coherent calculation. The mathematical model that we describe in the paper has three important advantages. First, the exact calculation of the phase-shift additions efficiently replaces various phase-averaging approaches normally used to deal with incoherency. Second, instead of an incoherent layer, we can use an equivalent coherent layer in a rigorous simulation using the phase-matching. Last, there is no energy imbalance error caused by wave coupling in lossy incoherent layers. We verify the proposed EMM against the general transfer-matrix method (GTMM) and the combined ray optics/wave optics model (CROWM) using two cases: an arbitrary multilayer structure with four incoherent glass layers, and a thin-film hydrogenated amorphous silicon solar cell. In both cases, the EMM yielded the same results as the GTMM and CROWM, thus confirming its regularity. Auteurs: J. Puhan;B. Lipovšek;Á. Bűrmen;I. Fajfar; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» An Achievable Rate Region Based on Coset Codes for Multiple Access Channel With States
 Résumé:We prove that the ensemble of the nested coset codes built on finite fields achieves the capacity of arbitrary discrete memoryless point-to-point channels. Exploiting its algebraic structure, we develop a coding technique for communication over general discrete multiple access channel with channel state information distributed noncausally at the transmitters. We build an algebraic coding framework for this problem using the ensemble of Abelian group codes and, thereby, derive a new achievable rate region. We identify non-additive and non-symmetric examples for which the proposed achievable rate region is strictly larger than the one achievable using random unstructured codes. Auteurs: Arun Padakandla;S. Sandeep Pradhan; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6393 - 6415 Editeur: IEEE Document complet vers site de l'éditeur
» An Adaptive Fixed-Point Iteration Algorithm for Finite-Element Analysis With Magnetic Hysteresis Materials
 Résumé:In this paper, an adaptive fixed-point iteration algorithm for 2-D/3-D finite-element analysis with hysteresis is proposed. The iteration starts with the $B$ -correction scheme. If the solution is not converged to a given accuracy after a certain number of iterations, the iteration will be continued by switching to the $H$ -correction scheme. Based on the combined use of the two correction schemes during the whole iteration process, the solution with the minimum error together with the scheme type is recorded and will be used as the final solution at the current time step. At the same time, the recorded scheme type will be used as the initial scheme type for the next time step. The numerical validation shows that the proposed algorithm not only has very fast convergence rate, but is also very stable. Auteurs: P. Zhou;D. Lin;C. Lu;M. Rosu;D. M. Ionel; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 5 Editeur: IEEE Document complet vers site de l'éditeur
» An Adaptive PAM-4 Analog Equalizer With Boosting-State Detection in the Time Domain
 Résumé:This paper introduces an improved adaptive analog equalizer that is required in high speed serial receivers using four-level pulse amplitude modulation signaling. By performing boosting-state detection in the time domain, the proposed adaptive analog equalizer can effectively overcome a serious problem that the received signal’s eye-opening tends to be compromised by the convergence accuracy of the adaptive control loop. To suppress the pattern-dependent jitters (PDJs), an inductor-less, cross-stage feedback structure is employed in the proposed analog equalizer to help broaden its effective tuning bandwidth. Multichannel simulations have confirmed that the proposed equalizer is able to achieve a 42% improvement in eye-height opening when compared with the equalizers employing popular spectrum-comparing schemes. Trellis diagram analyses under different date rates have revealed that the bandwidth of the proposed equalizer can be extended by as much as 60%, thus effectively bringing the PDJs from 44% down to 27.5%. Auteurs: Shunbin Li;Yingtao Jiang;Peng Liu; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2907 - 2916 Editeur: IEEE Document complet vers site de l'éditeur
» An Adaptive Strips Method for Extraction Buildings From Light Detection and Ranging Data
 Résumé:A method is proposed for extracting building points set from light detecting and ranging (LiDAR) data. This proposed method is based on a strip strategy to filter building points and extract the edge point set rapidly and effectively in large-scale urban building groups. This approach divides the LiDAR data into small strips and classifies each strip of data with an adaptive-weight polynomial in the $x$ - or $y$ -direction. The building edge set can then be extracted by utilizing the regional clustering relationships between points. The results of a series of experiments show that our method can not only filter the LiDAR point cloud, which performs better than existing methods, but also determine the building edge set efficiently, with an average accuracy rate of up to 91.1%. Auteurs: Xionggao Zou;Yueping Feng;Huiying Li;Jinlong Zhu; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1651 - 1655 Editeur: IEEE Document complet vers site de l'éditeur
» An Algorithm for Motif-Based Network Design
 Résumé:A determinant property of the structure of a biological network is the distribution of local connectivity patterns, i.e., network motifs. In this work, a method for creating directed, unweighted networks while promoting a certain combination of motifs is presented. This motif-based network algorithm starts with an empty graph and randomly connects the nodes by advancing or discouraging the formation of chosen motifs. The in- or out-degree distribution of the generated networks can be explicitly chosen. The algorithm is shown to perform well in producing networks with high occurrences of the targeted motifs, both ones consisting of three nodes as well as ones consisting of four nodes. Moreover, the algorithm can also be tuned to bring about global network characteristics found in many natural networks, such as small-worldness and modularity. Auteurs: Tuomo Mäki-Marttunen; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1181 - 1186 Editeur: IEEE Document complet vers site de l'éditeur
» An Analog Front-End Chip With Self-Calibrated Input Impedance for Monitoring of Biosignals via Dry Electrode-Skin Interfaces
 Résumé:This paper demonstrates an input impedance boosting method that was developed for long-term monitoring of electroencephalography signals. An instrumentation amplifier was designed with a negative capacitance generation feedback (NCGFB) technique to cancel the adverse effects of input capacitances from electrode cables and printed circuit boards. The NCGFB boosts the measured impedance from below 40 M $\Omega$ to above 500 M $\Omega$ at 50 Hz when the equivalent capacitance at the inputs is up to 150 pF. The prototype chip includes an automatic calibration system to adaptively enhance the input impedance through on-chip test signal generation, measurement, and the automatic digital control of the NCGFB. Consisting of an instrumentation amplifier, a low-pass notch filter, and a variable gain amplifier in 130-nm CMOS technology, the signal path has a combined gain range of 66–93 dB with a total power consumption of 42 $\mu$ W. The front-end bandwidth covers 0.5–48 Hz, and its integrated input-referred noise over the bandwidth is 3.75 $\mu$ Vrms. The measured third-order harmonic distortion component is at least 57 dB below the fundamental signal level. A common-mode rejection ratio of 77.6 dB and a power supply rejection ratio of 74 dB were measured at 10 Hz. When activated, the auxiliary test signal generation and calibration circuits consume a power of 542 $\mu$ W. Auteurs: Chun-Hsiang Chang;Seyed Alireza Zahrai;Kainan Wang;Li Xu;Ibrahim Farah;Marvin Onabajo; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2666 - 2678 Editeur: IEEE Document complet vers site de l'éditeur

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