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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 02-2018 trié par par titre, page: 6
» Gaussian Distributions on Riemannian Symmetric Spaces: Statistical Learning With Structured Covariance Matrices
Résumé:
The Riemannian geometry of covariance matrices has been essential to several successful applications, in computer vision, biomedical signal and image processing, and radar data processing. For these applications, an important ongoing challenge is to develop Riemannian-geometric tools which are adapted to structured covariance matrices. This paper proposes to meet this challenge by introducing a new class of probability distributions, Gaussian distributions of structured covariance matrices. These are Riemannian analogs of Gaussian distributions, which only sample from covariance matrices having a preassigned structure, such as complex, Toeplitz, or block-Toeplitz. The usefulness of these distributions stems from three features: 1) they are completely tractable, analytically, or numerically, when dealing with large covariance matrices; 2) they provide a statistical foundation to the concept of structured Riemannian barycentre (i.e., Fréchet or geometric mean); and 3) they lead to efficient statistical learning algorithms, which realise, among others, density estimation and classification of structured covariance matrices. This paper starts from the observation that several spaces of structured covariance matrices, considered from a geometric point of view, are Riemannian symmetric spaces. Accordingly, it develops an original theory of Gaussian distributions on Riemannian symmetric spaces, of their statistical inference, and of their relationship to the concept of Riemannian barycentre. Then, it uses this original theory to give a detailed description of Gaussian distributions of three kinds of structured covariance matrices, complex, Toeplitz, and block-Toeplitz. Finally, it describes algorithms for density estimation and classification of structured covariance matrices, based on Gaussian distribution mixture models.
Auteurs: Salem Said;Hatem Hajri;Lionel Bombrun;Baba C. Vemuri;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 752 - 772
Editeur: IEEE
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» Gaussian Process Regression for Virtual Metrology-Enabled Run-to-Run Control in Semiconductor Manufacturing
Résumé:
Incorporating virtual metrology (VM) into run-to-run (R2R) control enables the benefits of R2R control to be maintained while avoiding the negative cost and cycle time impacts of actual metrology. Due to the potential for prediction errors from VM models, the prediction as well as the corresponding confidence information on the predictions should be properly considered in VM-enabled R2R control schemes in order to guarantee control performance. This paper proposes the use of Gaussian process regression (GPR) models in VM-enabled R2R control due to their ability to provide this information in an integrated fashion. The mean value of the GPR prediction is treated as the VM value and the variance of the GPR prediction is used as a measure of confidence to adjust the coefficient of an exponentially weighted-moving-average R2R controller. The effectiveness of the proposed GPR VM-enabled R2R control approach is demonstrated using a chemical mechanical polishing process case study. Results show that better control performance is achieved with the proposed methodology than with implementations that do not take prediction reliability into account.
Auteurs: Jian Wan;Seán McLoone;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2018, volume: 31, issue:1, pages: 12 - 21
Editeur: IEEE
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» General Formulation of the Magnetostatic Field and Temperature Distribution in Electrical Machines Using Spectral Element Analysis
Résumé:
In this paper, a general approach to the description of the magnetic field and temperature distribution in electrical machines using the spectral element analysis is presented. In the spectral element method, higher order Legendre–Gauss–Lobatto polynomials are applied to describe the different fields. The magnetic flux distribution is derived using the magnetic vector potential, and nonlinear magnetic material is modeled based on its $BH$ curve. The thermal model is based on the heat equation. The magnetic and thermal domains are coupled by the ohmic and iron losses, and the latter is computed using the loss separation model of Bertotti. The results are compared with the finite element method, and a good agreement is obtained for both the spatial magnetic flux density and the temperature distributions.
Auteurs: M. Curti;T. A. Van Beek;J. W. Jansen;B. L. J. Gysen;E. A. Lomonova;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 02.-2018, volume: 54, issue:2, pages: 1 - 9
Editeur: IEEE
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» General Lagrange-Type Jacobian Inverse for Nonholonomic Robotic Systems
Résumé:
This paper discusses the nonholonomic robotic systems whose motion constraints assume the Pfaffian form, and the equations of motion are represented by driftless control systems with outputs. By reference to the end point map of such a control system, we define the system's Jacobian and study Jacobian motion-planning algorithms. A new Lagrange-type Jacobian inverse, referred to as the General Lagrangian Jacobian Inverse (GLJI), is designed as the solution of an optimal control problem with a Lagrange-type objective function. Singularities of GLJI are examined. A special choice of the objective function illustrates features of GLJI. A new motion-planning algorithm based on GLJI is proposed. Theoretical arguments are illustrated with a motion-planning problem of a space robot.
Auteurs: Krzysztof Tchoń;Joanna Ratajczak;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 256 - 263
Editeur: IEEE
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» Generalized HARQ Protocols with Delayed Channel State Information and Average Latency Constraints
Résumé:
In many wireless systems, the signal-to-interference-and-noise ratio that is applicable to a certain transmission, referred to as channel state information (CSI), can only be learned after the transmission has taken place and is thereby delayed (outdated). In such systems, hybrid automatic repeat request (HARQ) protocols are often used to achieve high throughput with low latency. This paper put forth the family of expandable message space (EMS) protocols, that generalize the HARQ protocol and allow for rate adaptation based on delayed CSI at the transmitter (CSIT). Assuming a block-fading channel, the proposed EMS protocols are analyzed using dynamic programming. When full delayed CSIT is available and there is a constraint on the average decoding time, it is shown that the optimal zero outage EMS protocol has a particularly simple operational interpretation and that the throughput is identical to that of the backtrack retransmission request (BRQ) protocol. We also devise EMS protocols for the case in which CSIT is only available through a finite number of feedback messages. The numerical results demonstrate that BRQ approaches the ergodic capacity quickly compared with HARQ, while EMS protocols with only three and four feedback messages achieve throughputs, that are only slightly worse than that of BRQ.
Auteurs: Kasper Fløe Trillingsgaard;Petar Popovski;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 02.-2018, volume: 64, issue:2, pages: 1262 - 1280
Editeur: IEEE
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» Generalized Memory Polynomial Model Dimension Selection Using Particle Swarm Optimization
Résumé:
This letter presents a new method which uses particle swarm optimization and the Akaike information criterion for determining the dimensions of nonlinear amplifier behavioral models, applied to the generalized memory polynomial model. Determining the size of this model has always been a challenge as it depends on eight parameters, and the proposed method provides a fast and efficient solution which can discover the smallest possible model at a very short amount of time.
Auteurs: A. Abdelhafiz;L. Behjat;F. M. Ghannouchi;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2018, volume: 28, issue:2, pages: 96 - 98
Editeur: IEEE
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» Generating Music from Literature Using Topic Extraction and Sentiment Analysis
Résumé:
This article presents Tambr, a new software for translating literature into sound using multiple synthesized voices selected for the way in which their timbre relates to the meaning and sentiment of the topics conveyed in the story. It achieves this by leveraging a large lexical semantic database to implement a machine-learning-based synthesizer search engine used to select the synthesizers whose meaning best reflects the ideas of the novel. Tambr uses sentiment analysis to generate the pitches, durations, and intervals of the output melodies in a way corresponding to the sentiment of the novel-implementing algorithmic composition of literature-based music at a level of musicality not previously explored.
Auteurs: Jessie Salas;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 15 - 18
Editeur: IEEE
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» Generation of Perfect Cylindrical Vector Beams With Complete Control Over the Ring Width and Ring Diameter
Résumé:
We propose the generation of high-purity perfect cylindrical vector beams (PCVB) using the Fourier transformation of Bessel–Gauss vector beams. The demonstration of PCVBs is implemented via an interferometric method employing a spatial light modulator that allows a fully independent control of the ring diameter ( $R_D$) and ring width ( $R_W$) of the PCVB. The proposed scheme enables to generate different types of cylindrical vector beams with precise user-defined transverse dimensions. The dynamic control of the ring width, ring diameter, and the specific type of PCVBs desired is theoretically as well as experimentally demonstrated. The proposed experimental setup can not only be employed in the generation of arbitrary PCVB, but also in perfect vortex beams. The ability to generate fully tailorable cylindrical vector beams and vortex beams has implications for the efficient launch of exotic optical modes in specialty fibers, in the field of optical tweezers as well as for superresolution microscopy.
Auteurs: Prabin Pradhan;Manish Sharma;Bora Ung;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 10
Editeur: IEEE
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» Generation of Polarization-Locked Vector Solitons in Mode-Locked Thulium Fiber Laser
Résumé:
In this paper, we report polarization-locked vector soliton (PLVS) generation in a linear thulium-doped fiber laser. The fiber laser was composed of all-anomalous-dispersion fibers, passively mode-locked with a semiconductor saturable absorber mirror. Approximately 1.2-ps single vector soliton pulses centered at 2023.7 nm were generated. Extra “peak-dip” spectral sidebands were clearly visible in the polarization-resolved optical spectra, indicating coherent energy exchange between the two polarization components of the vector solitons. In addition, multiple-PLVS operation modes were experimentally investigated, and our experimental results were confirmed by numerical simulations. To the best of our knowledge, this is the first observation of polarization-locked single vector soliton generation operating in the 2-μm spectral range.
Auteurs: X. L. Fan;Y. Wang;W. Zhou;X. J. Ren;Z. F. Hu;Q. Y. Liu;R. J. Zhang;D. Y. Shen;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 8
Editeur: IEEE
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» Generation of RF Intensity-Modulated Laser Pulses by Dual-Frequency Injection Seeding
Résumé:
In order to obtain high peak power RF intensity-modulated pulses for long-distance applications, a Q-switched Nd:YAG laser is injection seeded by a dual-frequency laser signal. The beat note frequency of the dual-frequency laser signal is adjusted to the frequency spacing of two adjacent longitudinal modes of the Q-switched laser. When the dual-frequency signal is injected into the Q-switched slave resonator, simultaneously two cavity axial modes are tuned to allow the injected wave frequencies within the axial modes selection range, the two selected slave cavity modes will oscillate due to phase-pulling effect. The Interference of the two modes results in intensity modulated pulses. The modulation frequency equals to a free spectral range of the Q-switched cavity, which is 225 MHz in our experiment. Maximum intensity-modulated pulse energy of 7 mJ and pulsewidth of 16 ns are measured. The dependence of locking bandwidth to the injected power is also studied experimentally, it is confirmed that the locking bandwidth increases with respect to the injected power of the seed signal. The high peak power RF intensity-modulated pulsed light source is a promising candidate for long-distance lidar-radar applications.
Auteurs: Lijun Cheng;Suhui Yang;Changming Zhao;Haiyang Zhang;Bingjie Sun;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 9
Editeur: IEEE
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» Generation Scheduling Optimization of Wind-Energy Storage System Based on Wind Power Output Fluctuation Features
Résumé:
As the output from wind power generation is intermittent in nature, making the wind power output “dependable” is critical for seamless integration of wind generation. One of the most favorable solutions is incorporating energy storage system (ESS) with wind farms to establish a wind-energy storage hybrid system. Since it requires capital investment for ESS installation, it is important to estimate appropriate storage capacity and charging/discharging rate of ESS for desired applications. In this paper, the fluctuation feature of wind power output is analyzed both in time domain and frequency domain. The degree of fluctuation is extracted and illustrated as quantization index (QI). Based on QI clustering, the wind scenario with largest power fluctuation is selected as “worst performance,” according to which, scheduling time horizon, along with the capacity and charging/discharging power of ESS, can be determined. After the case study, the proposed model is proved to improve the generation scheduling process.
Auteurs: Jie Shi;Wei-Jen Lee;Xiaofei Liu;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 10 - 17
Editeur: IEEE
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» Get Involved [Standards News]
Résumé:
As IAS Standards Department chair, my earnest appeal to all of you reading this article is to get involved in IAS standards. If you are an employer, convince your employees to join the standards-making group that aligns with your company's objectives.
Auteurs: Daleep Mohla;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 114 - 115
Editeur: IEEE
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» GeTrust: A Guarantee-Based Trust Model in Chord-Based P2P Networks
Résumé:
More and more users are attracted by P2P networks characterized by decentralization, autonomy and anonymity. However, users’ unconstrained behavior makes it necessary to use a trust model when establishing trust relationships between peers. Most existing trust models are based on recommendations, which, however, suffer from the shortcomings of slow convergence and high complexity of trust computations, as well as huge overhead of network traffic. Inspired by the establishment of trust relationships in human society, a guarantee-based trust model, GeTrust, is proposed for Chord-based P2P networks. A service peer needs to choose its guarantee peer(s) for the service it is going to provide, and they are both required to pledge reputation mortgages for the service. The request peer makes evaluations on all the candidates of service peer by referring their service reputations and their guarantee peers’ reputations, and selects the one with highest evaluation to be its service provider. In order to enhance GeTrust's availability and prevent malicious behavior, we also present incentive mechanism and anonymous reputation management strategy. Simulation results show that GeTrust is effective and efficient in terms of improving successful transaction rate, resisting complex attacks, reducing network overhead and lowering computational complexity.
Auteurs: Xianfu Meng;Dongxu Liu;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 02.-2018, volume: 15, issue:1, pages: 54 - 68
Editeur: IEEE
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» Getting into Microwaves and the MTT-S [Presidents' Column]
Résumé:
In this final “President's Column” as I end of my term as president of the IEEE Microwave Theory and Techniques Society (MTT-S), I have cause to reflect on how I became a microwave engineer and on the role the MTT-S has played in my career and the careers of my colleagues. Perhaps the most important functions of the Society are the MTT-S Distinguished Microwave Lecturer (DML) program, our conferences, and our publications. All of these contributed to my career, and I hope they are doing the same in yours.
Auteurs: Dylan Williams;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 8 - 10
Editeur: IEEE
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» Gibbsian On-Line Distributed Content Caching Strategy for Cellular Networks
Résumé:
In this paper, we develop Gibbs sampling-based techniques for learning the optimal placement of contents in a cellular network. We consider the situation where a finite collection of base stations are scattered on the plane, each covering a cell (possibly overlapping with other cells). Mobile users request downloads from a finite set of contents according to some popularity distribution which may be known or unknown to the base stations. Each base station has a fixed memory space that can store only a strict subset of the contents at a time; hence, if a user requests content that is not stored at any of its serving base stations, the content has to be downloaded from the backhaul. Hence, we consider the problem of optimal content placement which minimizes the rate of download from the backhaul, or equivalently maximize the cache hit rate. It is known that, when multiple cells can overlap with one another (e.g., under dense deployment of base stations in small cell networks), it is not optimal to place the most popular contents in each base station. However, the optimal content placement problem is NP-complete. Using the ideas of Gibbs sampling, we propose simple sequential content update rules that decide whether to store content at a base station (if required from the base station) and which content has to be removed from the corresponding cache, based on the knowledge of contents stored in its neighboring base stations. The update rule is shown to be asymptotically converging to the optimal content placement for all nodes under the knowledge of content popularity. Next, we extend the algorithm to address the situation where content popularities and cell topology are initially unknown, but are estimated as new requests arrive to the base stations; we show that our algorithm working with the running estimates of content popularities and cell topology also converges asymptotically to the optimal content placement. Finally, we- demonstrate the improvement in cache hit rate compared with the most popular content placement and independent content placement strategies via numerical exploration.
Auteurs: Arpan Chattopadhyay;Bartłomiej Błaszczyszyn;H. Paul Keeler;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 969 - 981
Editeur: IEEE
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» Global Data Registration Technology Based on Dynamic Coded Points
Résumé:
Field measurement of large aviation components is important in many fields of study. In this paper, a global data registration method based on the dynamic coded points is proposed. The system used in this method contains the local and global control binocular measurement systems. The local binocular measurement system measures the data of each subdomain as the local measurement data by scanning. The dynamic coded points, which are encoded based on time parameter as their encoded values, are projected to the measured object’s surface using a projector. Two sets of systems acquire the dynamic coded points to calculate their encoded values and match them automatically. These systems calculate the transformation relations between the local coordinate system and the global control coordinate system, so the local measurement data coordinates are integrated into the global control coordinate system through the transformation relations, achieving the global data registration. Experimental results in the laboratory show that the process of matching of dynamic coded points is accurate and has high robustness, and the global registration method based on the coded points proposed by this paper can eliminate the accumulated error, reaching the precision of 0.0150%. Field experimental results show that the registration method proposed in this paper satisfies the measurement requirements of large-scale aviation components.
Auteurs: Wei Liu;Zhiguang Lan;Yang Zhang;Zhiyuan Zhang;Haiyang Zhao;Fan Ye;Xiaodong Li;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 02.-2018, volume: 67, issue:2, pages: 394 - 405
Editeur: IEEE
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» Global Routing With Timing Constraints
Résumé:
We show how to incorporate global static timing constraints into global routing. Our approach is based on the min–max resource sharing model that proved successful for global routing in theory and practice. Static timing constraints are modeled by a linear number of additional resources and customers. The algorithm dynamically adjusts delay budgets and can, thus, tradeoff wiring congestion for delay. As a subroutine, the algorithm routes a single net. If this subroutine is near-optimal, we will find near-optimal solutions for the overall problem very efficiently. The approach works for many delay models; here we discuss a linear delay model (before buffering) and the Elmore delay model (after buffering). We demonstrate the benefit of our timing-constrained global routing algorithm by experimental results on industrial chips.
Auteurs: Stephan Held;Dirk Müller;Daniel Rotter;Rudolf Scheifele;Vera Traub;Jens Vygen;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 02.-2018, volume: 37, issue:2, pages: 406 - 419
Editeur: IEEE
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» GNSS Interference Detection Using Statistical Analysis in the Time-Frequency Domain
Résumé:
This paper presents a precorrelation interference detection method based on statistical analysis in the time-frequency (TF) domain for global navigation satellite system signals. In particular, the short-time Fourier transform (STFT) is considered as the TF tool due to its linear property and low computational complexity. A goodness-of-fit (GoF) test is applied to each frequency slice in the spectrogram of the received signal, which approximately follows a chi-square distribution in the absence of interference. The expected probability density function (PDF) of the observed TF-domain samples can be computed based on an interference-free signal or the noise power estimate. Two versions of the proposed technique are presented: one based on the canonical STFT with the maximum overlap size, and the other based on the block-wise STFT using nonoverlapped samples. The canonical STFT-based method shows better detection capability at the expense of degraded false alarm performance caused by the PDF distortion in the canonical STFT samples. The block-wise STFT-based method alleviates the false alarm issue but slightly weakens the detection capability. Simulations show that the proposed canonical and block-wise STFT-based methods improve the detection performance for both narrow- and wideband interference in low jammer-to-noise ratio environments when compared with the existing GoF test applied to the time-domain samples.
Auteurs: Pai Wang;Ediz Cetin;Andrew G. Dempster;Yongqing Wang;Siliang Wu;
Apparue dans: IEEE Transactions on Aerospace and Electronic Systems
Date publication: 02.-2018, volume: 54, issue:1, pages: 416 - 428
Editeur: IEEE
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» Goal-Driven Service Composition in Mobile and Pervasive Computing
Résumé:
Mobile, pervasive computing environments respond to users’ requirements by providing access to and composition of various services over networked devices. In such an environment, service composition needs to satisfy a request’s goal, and be mobile-aware even throughout service discovery and service execution. A composite service also needs to be adaptable to cope with the environment’s dynamic network topology. Existing composition solutions employ goal-oriented planning to provide flexible composition, and assign service providers at runtime, to avoid composition failure. However, these solutions have limited support for complex service flows and composite service adaptation. This paper proposes a self-organizing, goal-driven service model for task resolution and execution in mobile pervasive environments. In particular, it proposes a decentralized heuristic planning algorithm based on backward-chaining to support flexible service discovery. Further, we introduce an adaptation architecture that allows execution paths to dynamically adapt, which reduces failures, and lessens re-execution effort for failure recovery. Simulation results show the suitability of the proposed mechanism in pervasive computing environments where providers are mobile, and it is uncertain what services are available. Our evaluation additionally reveals the model’s limits with regard to network dynamism and resource constraints.
Auteurs: Nanxi Chen;Nicolás Cardozo;Siobhán Clarke;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 49 - 62
Editeur: IEEE
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» Good Preparation [Electrical Safety]
Résumé:
The author argues that it is easy to find connections between good preparation and safety, and electrical safety in particular. Many incidents, injuries, and fatalities occur when the scope changes on an electrical job. The workers may go into areas or equipment by mistake that are not properly de-energized. A well-prepared plan of action will clearly identify the scope of the job and help warn the workers to stop a job when the scope is changing. Good preparation will help identify the proper tools and test equipment needed and any special training that is required for the workers; without the right tools, test equipment, and training, there is a higher chance of an accident. A team that puts together a well-prepared plan of action can often reduce the number of electrical switching operations; this can dramatically lower the chance of a fault in the equipment during the job. As Miguel de Cervantes (1547–1616) said, "To be prepared is half the victory." For an electrical task, it should be considered a victory to have the job completed safely. Is your team prepared for every contingency?
Auteurs: Daniel Doan;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 6 - 6
Editeur: IEEE
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» Grading electric field in high voltage insulation using composite materials
Résumé:
Localized overstress due to electric field concentration is a threat to the long-term performance of the insulation in almost all high voltage apparatus. Resistive field grading using field grading materials (FGMs) may be a solution to this problem. Insulation matrixes such as ethylene propylene diene monomer, epoxy, or silicone rubbers, blended with fillers such as ZnO microvaristors, are reported to possess field dependent conductivity with greater and more stable nonlinearity than traditional FGMs [1]. Their application in high voltage apparatus such as bushings [1], cable accessories [2]-[4], insulators [5], [6], and stator coils [7] has been studied recently. It is well known [8] that the most important parameters for FGMs are the nonlinear coefficient α and switching field Eb; the challenge is to tailor these two parameters to a specific application. FGMs can function effectively in most cases when α >10 [9], but the adjustment of Eb is more complex.
Auteurs: Xiao Yang;Xiaolei Zhao;Jun Hu;Jinliang He;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2018, volume: 34, issue:1, pages: 15 - 25
Editeur: IEEE
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» Granular Differentiability of Fuzzy-Number-Valued Functions
Résumé:
In this paper, using the concept of horizontal membership functions, a new definition of fuzzy derivative called granular derivative is proposed based on granular difference. Moreover, a new definition of fuzzy integral called granular integral is defined, and its relation with the granular derivative is given. A new definition of a metric—granular metric—on the space of type-1 fuzzy numbers, and a concept of continuous fuzzy functions are also presented. Restrictions associated to previous approaches—Hukuhara differentiability, strongly generalized Hukuhara differentiability, generalized Hukuhara differentiability, generalized differentiability, Zadeh's extension principle, and fuzzy differential inclusions—dealing with fuzzy differential equations (FDEs) are expressed. It is shown that the proposed approach does not have the drawbacks of the previous approaches. It is also demonstrated how this approach enables researchers to solve FDEs more conveniently than ever before. Moreover, we showed that this approach does not necessitate that the diameter of the fuzzy function be monotonic. It is also proved that the result of each of the four basic operations on fuzzy numbers introduced based on the proposed approach leads to a fuzzy number. Moreover, the condition for the existence of the granular derivative of a fuzzy function is provided by a theorem. Additionally, by two examples, it is shown that the existence of the granular derivative of a fuzzy function does not imply the existence of the generalized Hukuhara differentiability of the fuzzy function, and vice versa. The terms doubling property and unnatural behavior in modeling phenomenon are also introduced. Furthermore, using some examples, the paper proceeds to elaborate on the efficiency and effectiveness of the proposed approach. Moreover, as an application of the proposed approach, the response of Boeing 747 to i- pulsive elevator input is obtained in the presence of uncertain initial conditions and parameters.
Auteurs: Mehran Mazandarani;Naser Pariz;Ali Vahidian Kamyad;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2018, volume: 26, issue:1, pages: 310 - 323
Editeur: IEEE
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» Graph-Based Modeling of Mobile Molecular Communication Systems
Résumé:
This letter develops a graph-based model of mobile molecular communication systems to study the spatio-temporal dynamics of bio-nanomachine concentration in a complex environment, such as the human circulatory system. We first consider the steady-state problem under the assumption that background flows are absent, and show that, at steady-state, bio-nanomachines on a graph distribute according to the target distribution. We then examine through numerical experiments the evolution of bio-nanomachine concentration on a graph in the presence of background flows. The graph-based model developed in this letter is useful to examine optimal conditions, under which drug-carrying bio-nanomachines distribute at target locations in a circulatory system.
Auteurs: Satoru Iwasaki;Tadashi Nakano;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 376 - 379
Editeur: IEEE
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» Graphene Terahertz Amplitude Modulation Enhanced by Square Ring Resonant Structure
Résumé:
A terahertz amplitude modulator based on graphene on a metallic square ring resonant structure is proposed. By separating the graphene and the metallic structure with a thin organic dielectric layer, both the resonant frequency and the amplitude of the transmission resonant peak are modulated when graphene is electrically tuned by a bias voltage. A maximal amplitude modulation depth of 72% at the frequency of 0.6 THz is achieved for the fabricated Terahertz modulator. An analysis model based on the transmission line theory is built to explore the modulation mechanism. Results of the transmission spectrum and the amplitude modulation indicate a good agreement between the transmission line theoretical predictions and the experimental measurements.
Auteurs: Liangping Xia;Xin Zhang;Dongshan Wei;Hong-Liang Cui;Chunlei Du;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 7
Editeur: IEEE
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» Graphene–Silicon-Based High-Sensitivity and Broadband Phototransistor
Résumé:
Graphene–silicon vertical junction is utilized here for fabrication of high-responsivity and broadband phototransistor. Graphene–silicon as a Schottky junction plays the role of collector–base junction in a bipolar junction phototransistor. We propose graphene–silicon-based phototransistor as a promising candidate for fabrication of high-gain photodetector with responsivity as high as 11 A/W. Gain and ON/OFF ratio of our fabricated device reach up to 18 and 100, respectively. Our results show that the graphene–silicon-based phototransistor is sensitive to a broad range of incident light from visible to IR spectrum. Our results open up a way to fabricate highly sensitive photodetectors suitable for silicon integrated electronics.
Auteurs: Aliakbar Hekmatikia;Yaser Abdi;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 216 - 219
Editeur: IEEE
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» Greetings from the New Editor-in-Chief [From the Editor's Desk]
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Robert Caverly;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 6 - 16
Editeur: IEEE
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» Grid Design for Efficient and Accurate Point Mass Filter-Based Terrain Referenced Navigation
Résumé:
This paper proposes an optimal grid design method for point mass filter-based terrain referenced navigation (PTRN) by considering the process and measurement uncertainties or noise to efficiently obtain accurate results. The estimation performance of the point mass filter (PMF) is generally known to improve when very large support and a high-resolution grid are implemented. However, when this condition is applied to the PTRN, the algorithm cannot be executed in real-time due to the high computational load. In addition, even though the grid condition is improved, the filter accuracy is limited by the given process and measurement noises. Therefore, it is possible to perform efficient and accurate PTRN by finding the minimum number of grid points that can achieve the maximum performance. In this paper, a grid design method is carried out by considering each noise, and the selection logic between the two design results are proposed. By applying the proposed grid design method, it is possible to obtain almost the same accuracy as the results that are obtained when a very high resolution is applied, with a much lower computational load, and it is expected for the highly accurate PTRN to be available in real-time.
Auteurs: Hyun Cheol Jeon;Woo Jung Park;Chan Gook Park;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1731 - 1738
Editeur: IEEE
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» GrIMS: Green Information-Centric Multimedia Streaming Framework in Vehicular Ad Hoc Networks
Résumé:
Information-centric networking (ICN), as a novel network paradigm, is expected to natively support mobility, multicast, and multihoming in vehicular ad hoc networks (VANETs). In this paper, the adoption of ICN principles for multimedia streaming in multihomed VANETs is investigated, with a major emphasis on the tradeoff between the quality of experience and energy efficiency (EnE). To formalize this problem, a cost optimization model is first proposed, based on queueing theory arguments. Then, a novel green information-centric multimedia streaming (GrIMS) framework is designed to drive the system toward optimal working points in practical settings. GrIMS consists of three enhanced mechanisms for on-demand cloud-based processing, adaptive multipath transmission, and cooperative in-network caching. Finally, a massive simulation campaign has been carried out, demonstrating that, thanks to its core components, the GrIMS enables flexible multimedia service provisioning and achieves an improved performance in terms of start-up delay, playbacks continuity, and EnE with respect to state-of-the-art solutions.
Auteurs: Changqiao Xu;Wei Quan;Hongke Zhang;Luigi Alfredo Grieco;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 483 - 498
Editeur: IEEE
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» Ground Moving Target Refocusing in SAR Imagery Using Scaled GHAF
Résumé:
In this paper, a new method is proposed to refocus a ground moving target in synthetic aperture radar imagery. In this method, range migration is compensated in the 2-D frequency domain, which can easily be implemented by using the complex multiplications, the fast Fourier transform (FFT), and the inverse FFT operations. Then, the received target signal in a range gate is characterized as a quadratic frequency-modulated (QFM) signal. Finally, a novel parameter estimation method, i.e., scaled generalized high-order ambiguity function (HAF), is proposed to transform the target signal into a signal on 2-D time–frequency plane and realize the 2-D coherent integration, where the peak position accurately determines the second- and third-order parameters of a QFM signal. Compared with our previously proposed generalized Hough-HAF method, the proposed method can obtain a better target focusing performance, since it can eliminate the incoherent operations in both range and azimuth directions. In addition, the proposed method is computationally efficient, since it is free of searching in the whole target focusing procedure. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm.
Auteurs: Penghui Huang;Xiang-Gen Xia;Guisheng Liao;Zhiwei Yang;Jianjiang Zhou;Xingzhao Liu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1030 - 1045
Editeur: IEEE
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» GSEH: A Novel Approach to Select Prostate Cancer-Associated Genes Using Gene Expression Heterogeneity
Résumé:
When a gene shows varying levels of expression among normal people but similar levels in disease patients or shows similar levels of expression among normal people but different levels in disease patients, we can assume that the gene is associated with the disease. By utilizing this gene expression heterogeneity, we can obtain additional information that abets discovery of disease-associated genes. In this study, we used collaborative filtering to calculate the degree of gene expression heterogeneity between classes and then scored the genes on the basis of the degree of gene expression heterogeneity to find “differentially predicted” genes. Through the proposed method, we discovered more prostate cancer-associated genes than 10 comparable methods. The genes prioritized by the proposed method are potentially significant to biological processes of a disease and can provide insight into them.
Auteurs: Hyunjin Kim;Sang-Min Choi;Sanghyun Park;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 129 - 146
Editeur: IEEE
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» Guest Editorial
Résumé:
The IEEE MTT-S International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO) is an annual international conference founded by the IEEE Microwave Theory and Techniques Society (MTT-S) in 2014. The idea of NEMO conference originated from the need to give special attention to the topics related to computational electromagnetics, advanced numerical techniques, and optimization algorithms and strategies. NEMO conferences are expected to be ideal venues to share new ideas on numerical techniques for electromagnetic/multiphysics modeling, propose efficient design algorithms and tools, and anticipate the modeling needs of future technologies and applications.
Auteurs: Francisco Mesa;Raúl Rodríguez-Berral;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 621 - 622
Editeur: IEEE
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» Guest Editorial Special Issue on Micropropulsion and Cubesats
Résumé:
This Special Issue is a broad forum presenting a series of topical reviews and original papers, addressing the hottest trends and recent progress in plasma propulsion physics, design, material solutions, and other aspects, as well as several review papers outlining progress in the selected regions and countries. Most were presented at the International Workshop on Micropropulsion and CubeSats (MPCS-2017), which took place at the CNR-Nanotec–P.Las.M.I. Lab, Bari, Italy. The third Conference will be held at the Micropropulsion and Nanotechnology Laboratory, George Washington University, Washington, DC, USA, followed by the fourth MPCS-IV in Beijing.
Auteurs: Igor Levchenko;Michael Keidar;Shuyan Xu;Francesco Taccogna;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 210 - 213
Editeur: IEEE
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» Guest Editorial Special Section on Engineering Industrial Big Data Analytics Platforms for Internet of Things
Résumé:
Over the last few years, a large number of Internet of Things (IoT) solutions have come to the IoT marketplace. Typically, each of these IoT solutions are designed to perform a single or minimal number of tasks (primary usage). We believe a significant amount of knowledge and insights are hidden in these data silos that can be used to improve our lives; such data include our behaviors, habits, preferences, life patterns, and resource consumption. To discover such knowledge, we need to acquire and analyze this data together in a large scale. To discover useful information and deriving conclusions toward supporting efficient and effective decision making, industrial IoT platform needs to support variety of different data analytics processes such as inspecting, cleaning, transforming, and modeling data, especially in big data context. IoT middleware platforms have been developed in both academic and industrial settings in order to facilitate IoT data management tasks including data analytics. However, engineering these general-purpose industrial-grade big data analytics platforms need to address many challenges. We have accepted six manuscripts out of 24 submissions for this special section (25% acceptance rate) after the strict peerreview processes. Each manuscript has been blindly reviewed by at least three external reviewers before the decisions were made. The papers are briefly summarized.
Auteurs: C. Perera;A. V. Vasilakos;G. Calikli;Q. Z. Sheng;K.-C. Li;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 744 - 747
Editeur: IEEE
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» Guest Editorial Special Section on Frontiers of DC Technology
Résumé:
Auteurs: D. Jovcic;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 259 - 259
Editeur: IEEE
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» Half-Duplex or Full-Duplex Communications: Degrees of Freedom Analysis Under Self-Interference
Résumé:
In-band full-duplex (FD) communication provides a promising alternative to half-duplex (HD) for wireless systems, due to increased spectral efficiency and capacity. In this paper, HD and FD radio implementations of two way, two hop, and two way two hop communication are compared in terms of degrees of freedom (DoF) under a realistic residual self-interference (SI) model. DoF analysis is carried out for each communication scenario for HD, antenna conserved (AC), and RF chain conserved (RC) FD radio implementations. The DoF analysis indicates that for the two way channel, the achievable AC FD with imperfect SI cancellation performs strictly below HD, and RC FD DoF tradeoff is superior when the SI can be sufficiently cancelled. For the two hop channel, FD is better when the relay has a large number of antennas and enough SI cancellation. For the two way two hop channel, when both nodes require similar throughput, the achievable DoF pairs for FD do not outperform HD. FD still can achieve better DoF pairs than HD, provided the relay has sufficient number of antennas and SI suppression.
Auteurs: Nirmal V. Shende;Özgür Gürbüz;Elza Erkip;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 1081 - 1093
Editeur: IEEE
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» Hall Thrusters With Permanent Magnets: Current Solutions and Perspectives
Résumé:
We present a focused review of selected design solutions for the permanent magnet-based magnetic circuitry of Hall-type thrusters, with the emphasis on their relevance to miniaturized devices potentially suitable for application in CubeSats and other types of small satellites. Coaxial, cylindrical, and cusped designs of Hall-type thrusters are considered. The issues related to the influence of magnetic configurations on channel wear are also addressed. This paper also outlines a state of the art in the high-temperature permanent magnets and offers some perspective views onto the further development of miniaturized Hall-type thrusters. Several nontrivial design solutions are considered, and schematics of the potentially promising ones for the reduction of wear and damage were examined. Overall, this paper demonstrates the usability and several significant advantages of Hall thrusters with permanent magnetic system.
Auteurs: Ludovico Lorello;Igor Levchenko;Kateryna Bazaka;Michael Keidar;Luxiang Xu;S. Huang;J. W. M. Lim;Shuyan Xu;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 239 - 251
Editeur: IEEE
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» Hand Gesture Recognition With Multiscale Weighted Histogram of Contour Direction Normalization for Wearable Applications
Résumé:
This paper proposes a static hand gesture recognition method with low computation and memory consumption for wearable applications. The hand contour is chosen as the hand gesture feature and support vector machine is used to classify the feature. A multiscale weighted histogram of contour direction-based direction normalization is proposed to ensure good recognition performance. In order to improve efficiency, the proposed histogram only counts the direction of the contour point to focus on the most significant hand feature in the first-person view of wearable devices. Based on the hand’s anatomy, the proposed histogram is weighted by considering each contour point’s position and direction jointly using the direction-angle map, to ensure robustness. Experimental results show that the proposed method can give a recognition accuracy of 97.1% with a frame rate of 30 fps on a PC.
Auteurs: Yiyi Ren;Xiang Xie;Guolin Li;Zhihua Wang;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 364 - 377
Editeur: IEEE
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» Hans Peter Luhn and the birth of the hashing algorithm
Résumé:
NOVEMBER 1958, AT A SIX-DAY INTERNATIONAL CONFERence devoted to scientific information, the inventor Hans Peter Luhn demonstrated a series of his electromechanical machines. They looked rather ordinary. Much like other computing devices of the day, they were boxy and utilitarian, designed to scoop and sort tall stacks of punch cards into slots and bins.
Auteurs: Hallam Stevens;
Apparue dans: IEEE Spectrum
Date publication: 02.-2018, volume: 55, issue:2, pages: 44 - 49
Editeur: IEEE
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» Hardware Implementation of the Preprocessing QR-Decomposition for the Soft-Output MIMO Detection With Multiple Tree Traversals
Résumé:
Compared with the single tree detector, the layered orthogonal lattice detector (LORD), developed by Siti et al., is a well-known soft-output multiple input multiple output detector to exploit ${M}$ parallel tree traversals to deliver data with ${M}$ times of detection throughput rate. The preprocessing QR-decomposition (QRD) of the ${M}$ -by- ${M}$ channel matrix for the single tree detector is of complexity proportional to ${M^{3}}$ . However, the preprocessing QRD for the LORD needs to compute the ${M}$ permuted channel matrices that are constructed from the original ${M}$ -by- ${M}$ channel matrix through the root conditioning criterion. The original LORD algorithm for this root conditioning QRD (RC-QRD) relies on the Gram-Schmidt orthogonalization and is of complexity proportional to ${M^{4}}$ for large ${M}$ . In this brief, we apply the Givens rotation and take advantage of the relationships among the ${M}$ permuted matrices to develop an RC-QRD algorithm with complexity proportional to ${M^{3}}$ . Furthermore, when ${M}$ is large, our proposed RC-QRD algorithm requires the number of real Givens rotations about 1.8 times necessary for computing a conventional matrix QRD. Also, for ${M=4}$ , our proposed RC-QRD hardware architecture requires gate count 2.1 times that required by the conventional triangular systolic array to compute a matrix QRD. Accordingly, with only about two times of complexity for the preprocessing RC-QRD, the LORD is able to perform ${M}$ tree traversals to deliver data with ${M}$ times of throughput rate.
Auteurs: Tsung-Hsien Liu;Yi-Kuang Ko;Yen-Ju Chiu;Wen-Yen Lin;Yuan-Sun Chu;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 02.-2018, volume: 65, issue:2, pages: 186 - 190
Editeur: IEEE
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» Harmonically-Driven Snapping of a Micromachined Bistable Mechanism With Ultra-Small Actuation Stroke
Résumé:
In this paper, we study the snapping action of a micromachined bistable mechanism harmonically driven with an ultra-small actuation stroke, which is realized through the mode amplification in a two-degrees-of-freedom (2-DOF) vibration system using an on-chip electrostatic actuator. The micromachined bistable mechanism is based on a curved beam configuration. The dynamic response of the device is theoretically predicted with the harmonic balance method. Further, to demonstrate this proposed study, a microelectromechanical systems (MEMS) prototype device is designed, fabricated, and tested. In experiments, the forward and backward state switching actions of the prototype device are realized with actuation stroke smaller than $0.4~mu text{m}$ , while the traveling distance between the two states is about $18~mu text{m}$ . To the best of our knowledge, we demonstrate for the first time the state switching of a cured beam bistable mechanism using harmonic driving in a 2-DOF vibration system. This paper has potential in applications including MEMS switches and MEMS filters. [2017-0221]
Auteurs: Han Du;Fook Siong Chau;Guangya Zhou;
Apparue dans: Journal of Microelectromechanical Systems
Date publication: 02.-2018, volume: 27, issue:1, pages: 34 - 39
Editeur: IEEE
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» Harnessing Laguerre-Gaussian Beams to Construct Quasi-Nondiffracting Optical Ring Lattices
Résumé:
We construct a family of optical ring lattices that manifest the quasi-nondiffracting property via superposition of high-radial-order Laguerre-Gaussian beams. A theoretical derivation of the optical ring lattice along with the validity condition is presented, and its evolution behaviors are investigated in comparison with the diffraction-free Bessel beams. Moreover, multiple ultralong bright channels or optical tubes with various transverse profiles can be formed with the ring optical lattices. As a proof of concept, flexible generation of the lattice beams was demonstrated by complex wavefront engineering using a binary digital micromirror device. We anticipate that the quasi-nondiffracting ring lattices and the ultralong optical channels might motivate novel applications in optical trapping and high-resolution microscopy.
Auteurs: Qian Zhao;Lei Gong;Xin-Yao Hu;Pan-Pan Yu;Zi-Qiang Wang;Yin-Mei Li;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 7
Editeur: IEEE
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» Hello, World!—Code Responsibly
Résumé:
Many security exploits target vulnerabilities that are a result of poorly designed and implemented software. Despite its critical importance, secure coding is primarily taught in upper-level elective computer science (CS) classes. As a result, most students graduate with little or no exposure to secure coding techniques. We believe that it is important to teach responsible coding early, starting in the first programming course, and often, by repeating and reinforcing security concepts in advanced courses. At Towson University, we have developed modules that teach students to code securely and responsibly from the first class: the Security Injections @Towson project.
Auteurs: Siddharth Kaza;Blair Taylor;Kyle Sherbert;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2018, volume: 16, issue:1, pages: 98 - 100
Editeur: IEEE
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» HEMEsPred: Structure-Based Ligand-Specific Heme Binding Residues Prediction by Using Fast-Adaptive Ensemble Learning Scheme
Résumé:
Heme is an essential biomolecule that widely exists in numerous extant organisms. Accurately identifying heme binding residues (HEMEs) is of great importance in disease progression and drug development. In this study, a novel predictor named HEMEsPred was proposed for predicting HEMEs. First, several sequence- and structure-based features, including amino acid composition, motifs, surface preferences, and secondary structure, were collected to construct feature matrices. Second, a novel fast-adaptive ensemble learning scheme was designed to overcome the serious class-imbalance problem as well as to enhance the prediction performance. Third, we further developed ligand-specific models considering that different heme ligands varied significantly in their roles, sizes, and distributions. Statistical test proved the effectiveness of ligand-specific models. Experimental results on benchmark datasets demonstrated good robustness of our proposed method. Furthermore, our method also showed good generalization capability and outperformed many state-of-art predictors on two independent testing datasets. HEMEsPred web server was available at http://www.inforstation.com/HEMEsPred/ for free academic use.
Auteurs: Jian Zhang;Haiting Chai;Bo Gao;Guifu Yang;Zhiqiang Ma;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 147 - 156
Editeur: IEEE
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» Hepta-Band Coupled-Fed Loop Antenna For LTE/WWAN Unbroken Metal-Rimmed Smartphone Applications
Résumé:
A hepta-band coupled-fed loop antenna for LTE/WWAN unbroken metal-rimmed smartphone applications is proposed. The unbroken metal rim is designed as a part of the loop antenna radiation structure, which is also composed of a system ground, a coupled-fed U-shaped microstrip line, and an L-shaped microstrip line. The feeding and L-shaped microstrip lines are located on an ungrounded area of 72 × 8 mm2 along the top short edge of the system ground plane on an FR4 substrate. The operating band of the antenna is widened by the matching circuit elements on the feeding line. Combining multiple resonant modes generated by the coupling loop, the proposed antenna can operate on two wide operating bands of 824–960 and 1710–2690 MHz. The detailed working principles of the proposed antenna are described. Good antenna radiation characteristics are obtained. Both experimental and simulation results are presented and discussed.
Auteurs: Zi-Qiang Xu;Qiang-Qiang Zhou;Yong-Ling Ban;Simon S. Ang;
Apparue dans: IEEE Antennas and Wireless Propagation Letters
Date publication: 02.-2018, volume: 17, issue:2, pages: 311 - 314
Editeur: IEEE
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» Heuristic Algorithm for a WIP Projection Problem at Finite Capacity in Semiconductor Manufacturing
Résumé:
In this paper, we propose a heuristic approach for fixing work-in-progress (WIP) projection issues in the semiconductor industry especially for high mix low volume facilities. The considered problem consists of estimating the start and end dates for each remaining process step of the production lots in the WIP and anticipating the fab loading taking into account the constraints of the maximum throughput of machines considered as capacity constraints and customer delivery commitments. The objective being to guarantee on-time delivery, we focus on minimizing the total weighted tardiness. We have formulated the problem into a mixed-integer programming and we have empirically shown its computational intractability. Due to the computational intractability using actual production data, a heuristic algorithm is proposed. It is an iterative finite capacity planning system that considers as inputs lots due dates and equipment capabilities and capacities. The performance of the heuristic is assessed using industrial instances. It turns out that it achieves targeted objectives with satisfactory results in terms of quality of the solution and computation time.
Auteurs: Emna Mhiri;Fabien Mangione;Mireille Jacomino;Philippe Vialletelle;Guillaume Lepelletier;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2018, volume: 31, issue:1, pages: 62 - 75
Editeur: IEEE
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» HfO2/Ti Interface Mediated Conductive Filament Formation in RRAM: An Ab Initio Study
Résumé:
We address the role of the Ti/HfO2 interface on the conductive filament (CF) formation within the context of oxide-based resistive random access memories (OxRRAMs). We investigate oxygen defects formation and diffusion at the interface through ab initio calculations. The calculated diffusion energy barriers compare well with the available experimental data. Through the interface region charge analysis and the associated energies with O defect formation and migration into Ti, our results support a probable CF growth from the interface region toward the electron injecting electrode, which acts as a cathode. Hence, for a Ti/HfO2-based OxRRAM supported by the calculation results, we present a pertinent CF growth model by considering its earliest stages, which is relevant for device modeling.
Auteurs: Boubacar Traore;Philippe Blaise;Benoît Sklénard;Elisa Vianello;Blanka Magyari-Köpe;Yoshio Nishi;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 507 - 513
Editeur: IEEE
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» Hierarchical Control Design for a Shipboard Power System With DC Distribution and Energy Storage Aboard Future More-Electric Ships
Résumé:
DC distribution is now becoming the major trend of future mobile power systems, such as more-electric aircrafts and ships. As dc distribution has different nature to the conventional ac system, a new design of well-structured control and management methods will be mandatory. In this paper, a shipboard power system with dc distribution and energy storage system (ESS) is picked as the study case. To meet the requirement of control and management of such a large-scale mobile power system, a hierarchical control design is proposed in this paper. In order to fully exploit the benefit of the ESS, as well as to overcome the limitation in controllability, a novel inverse-droop control method is proposed, in which the power sharing is according to the source characteristic, instead of their power rating. A frequency-division method is also proposed as an extension to the inverse-droop method for enabling a hybrid ESS and its autonomous operation. On the basis of the proposed methods, the control methods for management and voltage restoration levels are also proposed to establish a comprehensive control solution. Real-time simulations are carried out to validate the performance of the proposed control design under different operating conditions. When compared to more conventional droop-based approaches, the new proposal shows enhancement in efficiency.
Auteurs: Zheming Jin;Lexuan Meng;Josep M. Guerrero;Renke Han;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 703 - 714
Editeur: IEEE
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» Hierarchical Decentralized Optimization Architecture for Economic Dispatch: A New Approach for Large-Scale Power System
Résumé:
In this paper, a new hierarchical decentralized optimization architecture is proposed to solve the economic dispatch problem for a large-scale power system. Conventionally, such a problem is solved in a centralized way, which is usually inflexible and costly in computation. In contrast to centralized algorithms, in this paper we decompose the centralized problem into local problems. Each local generator only solves its own problem iteratively, based on its own cost function and generation constraint. An extra coordinator agent is employed to coordinate all the local generator agents. Besides, it also takes responsibility to handle the global demand supply constraint based on a newly proposed concept named virtual agent. In this way, different from existing distributed algorithms, the global demand supply constraint and local generation constraints are handled separately, which would greatly reduce the computational complexity. In addition, as only local individual estimate is exchanged between the local agent and the coordinator agent, the communication burden is reduced and the information privacy is also protected. It is theoretically shown that under proposed hierarchical decentralized optimization architecture, each local generator agent can obtain the optimal solution in a decentralized fashion. Several case studies implemented on the IEEE 30-bus and the IEEE 118-bus are discussed and tested to validate the proposed method.
Auteurs: Fanghong Guo;Changyun Wen;Jianfeng Mao;Jiawei Chen;Yong-Duan Song;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 523 - 534
Editeur: IEEE
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» Hierarchical Force and Positioning Task Specification for Indirect Force Controlled Robots
Résumé:
Indirect force control (IFC) architectures are a common approach for dealing with unknown environments. What all IFC schemes have in common is that the relation between the set point and the actual configuration of the robot is determined by a mechanical relationship (e.g., a mass–spring–damper system). In this paper, we propose a set-point generation method for IFC schemes, enabling intuitive specification of mixed force and positioning tasks on joint and Cartesian levels. In addition, the formulation of equality and inequality tasks is supported and a passivity-based stability proof is formulated using the concept of virtual energy storage. The resulting task programming interface is demonstrated on a 7-degree-of-freedom robot, running a joint space impedance controller. One sample task demonstrates the application of the developed approach and highlights the basic features.
Auteurs: Ewald Lutscher;Emmanuel C. Dean-León;Gordon Cheng;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2018, volume: 34, issue:1, pages: 280 - 286
Editeur: IEEE
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» Hierarchical System Modeling
Résumé:
In this study, we present a methodology of building a hierarchical framework of system modeling by engaging concepts and design methodology of granular computing. We demonstrate that it arises as a result of designing and using locally constructed models to develop a model of a global nature. Two main categories of development of hierarchical models are proposed and discussed. In the first one, given a collection of local models, designed is a granular output space and the ensuing hierarchical model produces information granules of the corresponding type depending upon the depth of the hierarchy of the overall hierarchical structure. The crux of the second category of modeling is about selecting one of the original models and elevating its level of information granularity so that it becomes representative of the entire family of local models. The formation of the most “promising” granular model identified in this way involves mechanisms of allocation of information granularity. The focus of the study is on information granules represented as intervals and fuzzy sets (which in case of type-2 information granules lead to so-called granular intervals and interval-valued fuzzy sets) while the detailed models come as rule-based architectures and neural networks. A series of experiments is presented along with a comparative analysis.
Auteurs: Rami Al-Hmouz;Witold Pedrycz;Abdullah Saeed Balamash;Ali Morfeq;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2018, volume: 26, issue:1, pages: 258 - 269
Editeur: IEEE
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» Hierarchical Trajectory Planning of an Autonomous Car Based on the Integration of a Sampling and an Optimization Method
Résumé:
This paper presents a hierarchical trajectory planning based on the integration of a sampling and an optimization method for urban autonomous driving. To manage a complex driving environment, the upper behavioral trajectory planner searches the macro-scale trajectory to determine the behavior of an autonomous car by using environment models, such as traffic control device and objects. This planner infers reasonable behavior and provides it to the motion trajectory planner. For planning the behavioral trajectory, the sampling-based approach is used due to its advantage of a free-form cost function for discrete models of the driving environments and simplification of the searching area. The lower motion trajectory planner determines the micro-scale trajectory based on the results of the upper trajectory planning with the environment model. The lower planner strongly considers vehicle dynamics within the planned behavior of the behavioral trajectory. Therefore, the planning space of the lower planner can be limited, allowing for improvement of the efficiency of the numerical optimization of the lower planner to find the best trajectory. For the motion trajectory planning, the numerical optimization is applied due to its advantages of a mathematical model for the continuous elements of the driving environments and low computation to converge minima in the convex function. The proposed algorithms of the sampling-based behavioral and optimization-based motion trajectory were evaluated through experiments in various scenarios of an urban area.
Auteurs: Wonteak Lim;Seongjin Lee;Myoungho Sunwoo;Kichun Jo;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 02.-2018, volume: 19, issue:2, pages: 613 - 626
Editeur: IEEE
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» Hierarchical, Portfolio Theory-Based Virtual Machine Consolidation in a Compute Cloud
Résumé:
Improving the energy efficiency of cloud computing systems has become an important issue because the electric energy bill for 24/7 operation of these systems can be quite large. The focus of this paper is on the virtual machine consolidation in a cloud computing system as a way of lowering daily energy consumption of the system. In contrast to the existing works that assume resource demands of virtual machines are given as scalar variables, this paper treats these demands as random variables with known means and standard deviations because the demands are not deterministic in many situations. These random variables may be correlated with one another, and there are several types of resources which can be performance bottlenecks. Therefore, both correlations and resource type heterogeneity must be considered. The virtual machine consolidation problem is thus formulated as a multi-capacity stochastic bin packing problem. This problem is NP-hard, so we present a heuristic method to efficiently solve the problem. Simulation results show that, in spite of its simplicity and scalability, the proposed method produces high quality solutions.
Auteurs: Inkwon Hwang;Massoud Pedram;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 63 - 77
Editeur: IEEE
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» High Al-Content AlGaN Transistor With 0.5 A/mm Current Density and Lateral Breakdown Field Exceeding 3.6 MV/cm
Résumé:
We report on ultra-wide bandgap (UWBG) Al0.7Ga0.3N channel metal–oxide–semiconductor field-effect transistors (MOSFETs) grown by metal-organic chemical vapor deposition. Employing reverse Al composition graded ohmic contact layers and 20 nm Al2O3 gate-dielectric, 250 nm thick Al0.7Ga0.3N:Si channel MOSFETs resulted in the maximum current density of 0.5 A/mm, which is the highest value reported for AlGaN channels with Al composition >0.25. Transistors with a gate-drain spacing ( $L_{mathrm{ GD}})$ of $1.7~mu text{m}$ demonstrated a breakdown voltage ( $V_{mathrm{ DG}})$ of ~620 V, translating in an average lateral breakdown field of ~3.6 MV/cm. This work establishes UWBG AlGaN as a promising candidate for advanced RF applications.
Auteurs: Sanyam Bajaj;Andrew Allerman;Andrew Armstrong;Towhidur Razzak;Vishank Talesara;Wenyuan Sun;Shahadat H. Sohel;Yuewei Zhang;Wu Lu;Aaron R. Arehart;Fatih Akyol;Siddharth Rajan;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 256 - 259
Editeur: IEEE
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» High Dynamics Control for MMC Based on Exact Discrete-Time Model With Experimental Validation
Résumé:
Due to the complexity of the system, the control of the modular multilevel converter (MMC) constitutes an intense research activity. The stored energy inside the MMC presents a new degree of freedom, which can be exploited to provide ancillary services (oscillation damping for example). In order to do so, the response time of the energy loop has to be as fast as possible. However, when a cascaded approach is used to control the structure, this purpose cannot be achieved without fast inner loops. This paper presents a novel inner loops controller in order to obtain a high response dynamic. These controllers have been developed based on exact discrete-time models obtained from an analytic calculation of exponential of matrices. A pole placement method using feedback control has been chosen to derive their control laws. For stability matters, a pole location analysis is used to set appropriately the controller parameters, which are the sampling period and the controller gains. After validation with offline simulations and in order to show the advantages of the proposed controllers compared to the existing solutions, experimental tests have been performed using a real small-scale MMC.
Auteurs: Ahmed Zama;Abdelkrim Benchaib;Seddik Bacha;David Frey;Sébastien Silvant;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 477 - 488
Editeur: IEEE
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» High Efficiency Quantum Cascade Lasers Based on Excited-States Injection
Résumé:
In this letter, quantum cascade lasers (QCLs) based on excited-states injection are presented. The operating voltage is significantly reduced compared with the conventional ground-state injection design. Devices emitting at $sim 5.25mu text{m}$ were fabricated through standard buried-heterostructure processing. Stable single-mode emission was observed by implementing a buried first-order distributed feedback (DFB) grating. The maximum output power of the DFB QCL with 2-mm cavity length was more than 300 mW at 10 °C with a high wall-plug efficiency of 5.6% in continuous-wave mode.
Auteurs: Chuan-Wei Liu;Jin-Chuan Zhang;Feng-Min Cheng;Yue Zhao;Ning Zhuo;Shen-Qiang Zhai;Li-Jun Wang;Jun-Qi Liu;Shu-Man Liu;Feng-Qi Liu;Zhan-Guo Wang;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 299 - 302
Editeur: IEEE
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» High Frequency SSVEP-BCI With Hardware Stimuli Control and Phase-Synchronized Comb Filter
Résumé:
We present an efficient implementation of brain–computer interface (BCI) based on high-frequency steady state visually evoked potentials (SSVEP). Individual shape of the SSVEP response is extracted by means of a feedforward comb filter, which adds delayed versions of the signal to itself. Rendering of the stimuli is controlled by specialized hardware (BCI Appliance). Out of 15 participants of the study, nine were able to produce stable response in at least eight out of ten frequencies from the 30–39 Hz range. They achieved on average 96±4% accuracy and 47±5 bit/min information transfer rate (ITR) for an optimized simple seven-letter speller, while generic full-alphabet speller allowed in this group for 89±9% accuracy and 36±9 bit/min ITR. These values exceed the performances of high-frequency SSVEP-BCI systems reported to date. Classical approach to SSVEP parameterization by relative spectral power in the frequencies of stimulation, implemented on the same data, resulted in significantly lower performance. This suggests that specific shape of the response is an important feature in classification. Finally, we discuss the differences in SSVEP responses of the participants who were able or unable to use the interface, as well as the statistically significant influence of the layout of the speller on the speed of BCI operation.
Auteurs: Anna Chabuda;Piotr Durka;Jarosław Żygierewicz;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 344 - 352
Editeur: IEEE
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» High Performance Parallel Single-Phase Converter Reconfiguration for Enhanced Availability
Résumé:
Paralleling power converters is a common practice in industries to enhance total power rating, reliability, and availability of the system. In case of fault occurring in systems with parallel converters, the faulty power converter can be isolated and the system can still be operated at reduced power level. In this paper, a grid-connected power converter consisting of two parallel H-bridge converters with low ground leakage current is considered. Two contingency configurations, that are also of low ground leakage current, are proposed to enhance the availability of the system. This is done by reconfiguring the power circuit to a single H-bridge in the case of failure in one of the bridges. The power converter is experimentally tested with the proposed configurations for experimental validation. The results show that the second configuration has better performance in terms of power loss and current total harmonic distortion when operating at lower power level.
Auteurs: Mohammad Hassan Hedayati;Vinod John;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 388 - 394
Editeur: IEEE
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» High-Efficiency mosfet-Based MMC Design for LVDC Distribution Systems
Résumé:
Low-voltage dc (LVdc) distribution networks have the potential to release larger capacity without having to upgrade the existing cables. One of the main challenges of LVdc networks is the extra customer-end dc–ac conversion stage. This paper proposes and evaluates a five-level Si mosfet-based modular multilevel converter (MMC) as a promising alternative to the conventional two-level insulated gate bipolar transistor-based converter. This is due to the comparatively higher efficiency, power quality and reliability, and reduced electromagnetic (EM) emissions. A comprehensive analysis of a Si mosfet five-level MMC converter design is performed to investigate the suitability of the topology for LVdc applications. Detailed theoretical analysis of the five-level MMC is presented, with simulated and experimental results to demonstrate circuit performance. To suppress the ac circulating current, especially the dominant second harmonics, this paper presents a double line-frequency proportional integral (PI) with orthogonal imaginary axis control method. Comparison of simulation and experimental results with those for double line-frequency proportional resonant control shows that the proposed PI controller has a better performance. In addition, it is simpler to implement and more immune to sampling/discretization errors.
Auteurs: Yanni Zhong;Nina Roscoe;Derrick Holliday;Tee Chong Lim;Stephen J. Finney;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 321 - 334
Editeur: IEEE
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» High-Efficiency Input and Output Harmonically Engineered Power Amplifiers
Résumé:
This paper presents an in-depth, systematic study of the impact of input and output harmonics in the design of high-efficiency power amplifiers (PAs). The study evaluates the performance of harmonically tuned amplifiers, tackling concurrently both input and output harmonics. The proposed theory starts with deriving an altered input voltage waveform under the impact of input nonlinearity. Intrinsic drain voltage and drain current components are formulated as a function of the conduction angle $alpha $ considering both source and load terminations. Output power and drain efficiency are then computed as a function of input nonlinearity, $alpha $ , and output loading conditions. The derived formulations allow to investigate the design sensitivity to input nonlinearity and its impact on fundamental design space. The impact of source harmonics is evaluated using harmonic source pull under different output loading conditions. Thereafter, PA design and implementation has been carried out using NXP 1.95 mm die to confirm the distinctive behavior of class GF and GF−1 amplifiers with respect to the input harmonic terminations. For practical validation, four different design cases with different second harmonic source impedances are investigated. At 2.6 GHz, drain efficiencies ranging between 76% and 83% were exhibited depending on the source and load harmonic tuning for each design case. Measurement results confirm the theoretical findings reported in this paper.
Auteurs: Tushar Sharma;E. R. Srinidhi;Ramzi Darraji;Damon G. Holmes;Joseph Staudinger;Jeffrey K. Jones;Fadhel M. Ghannouchi;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 1002 - 1014
Editeur: IEEE
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» High-Level Programming Abstractions for Distributed Graph Processing
Résumé:
Efficient processing of large-scale graphs in distributed environments has been an increasingly popular topic of research in recent years. Inter-connected data that can be modeled as graphs appear in application domains such as machine learning, recommendation, web search, and social network analysis. Writing distributed graph applications is inherently hard and requires programming models that can cover a diverse set of problems, including iterative refinement algorithms, graph transformations, graph aggregations, pattern matching, ego-network analysis, and graph traversals. Several high-level programming abstractions have been proposed and adopted by distributed graph processing systems and big data platforms. Even though significant work has been done to experimentally compare distributed graph processing frameworks, no qualitative study and comparison of graph programming abstractions has been conducted yet. In this survey, we review and analyze the most prevalent high-level programming models for distributed graph processing, in terms of their semantics and applicability. We review 34 distributed graph processing systems with respect to the graph processing models they implement and we survey applications that appear in recent distributed graph systems papers. Finally, we discuss trends and open research questions in the area of distributed graph processing.
Auteurs: Vasiliki Kalavri;Vladimir Vlassov;Seif Haridi;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 02.-2018, volume: 30, issue:2, pages: 305 - 324
Editeur: IEEE
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» High-Order-Tilted Fiber Bragg Gratings With Superposed Refractive Index Modulation
Résumé:
A high-order-tilted fiber Bragg gratings (HO-TFBG) with superposed refractive index (RI) modulation written by a femtosecond laser and a phase mask has been demonstrated. The superposed grating structure is realized by the combined action of the pure ±1 order pulses interference and the heat accumulation effect of ±1 order and zero-order pulses. For the phase mask with the pitch of 3.33 μm, there are 11 groups of high-order Bragg resonance and cladding mode resonances sets in the wavelength range of 600–1700 nm, the information carried by which is doubled compared to the HO-TFBG written by pure two beams interference. It demonstrates that the sensitivities of the cladding mode resonances sets to surrounding RI, axial strain and temperature decrease with the increase of the grating order.
Auteurs: Xuan-Yu Zhang;Chao Chen;Yong-Sen Yu;Wei-Hua Wei;Qi Guo;Yong-Yi Chen;Xing Zhang;Li Qin;Yong-Qiang Ning;Hong-Bo Sun;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 8
Editeur: IEEE
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» High-Performance MMIC Inductors for GaN-on-Low-Resistivity Silicon for Microwave Applications
Résumé:
Novel MMIC spiral inductors on GaN-on-low-resistivity silicon (LR-Si) substrates ( $sigma < 40~Omega cdot text {cm}$ ) are demonstrated with enhanced self-resonance frequency ( $f_{mathrm{ SRF}}$ ) and $Q$ -factor. The developed technology improves inductor performance by suppressing substrate coupling effects using air-bridge technology above benzocyclobutene dielectric as an interface layer on the lossy substrate. A 0.83-nH spiral inductor with peak $Q$ -factor enhancement of 57% ( $Q = 22$ at 24 GHz) and maximum $f_{mathrm{ SRF}}$ of 59 GHz was achieved because of the extra 5- $mu text{m}$ elevation in air. An accurate broad-band model for the fabricated inductors has been developed and verified for further performance analysis up to 40 GHz. The proposed inductors utilize cost-effective, reliable, and MMIC-compatible technology for the realization of high-performance RF GaN-on-LR Si MMIC circuits for millimeter-wave applications.
Auteurs: A. Eblabla;X. Li;D. J. Wallis;I. Guiney;K. Elgaid;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2018, volume: 28, issue:2, pages: 99 - 101
Editeur: IEEE
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» High-Performance Ultrasound Needle Transducer Based on Modified PMN-PT Ceramic With Ultrahigh Clamped Dielectric Permittivity
Résumé:
A modified Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) polycrystalline ceramic with ultrahigh relative clamped dielectric permittivity ( $varepsilon ^{S}/varepsilon _{0} = 3500$ ) and high piezoelectric properties ( $d_{33}= 1200$ pC/N, $k_{t} = 0.55$ ) was used to fabricate high-frequency miniature ultrasound transducers. A 39-MHz high-frequency ultrasound needle transducer with a miniature aperture of 0.4 mm $times0.4$ mm was designed and successfully characterized. The fabricated needle transducer had an electromechanical coupling factor $k_{t}$ of 0.55, large bandwidth of 80% at −6 dB, and low insertion loss of −13 dB. A wire phantom and porcine eyeball imaging study showed good imaging capability of this needle transducer. The transducer performance was found to be superior to that of other needle transducers with miniature apertures, making this modified PMN-PT ceramic-based needle transducer quite promising for minimally invasive procedures in medical applications.
Auteurs: Zhiqiang Zhang;Fei Li;Ruimin Chen;Tianfu Zhang;Xiaodong Cao;Shujun Zhang;Thomas R. Shrout;Hairong Zheng;K. Kirk Shung;Mark S. Humayun;Weibao Qiu;Qifa Zhou;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 223 - 230
Editeur: IEEE
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» High-Purity Sine Wave Generation Using Nonlinear DAC With Predistortion Based on Low-Cost Accurate DAC–ADC Co-Testing
Résumé:
Data converters are among the most widely used components in modern integrated devices and systems. A major challenge is to characterize their performances accurately and cost effectively. The analog-to-digital converter (ADC) standard test requires the input sinusoidal signal to be 3–4 b better than that of the ADC under test. Such high-quality sine waves are extremely difficult to generate and challenging to implement cost effectively. This paper presents a novel method that is capable of generating a high-purity sine wave using a nonlinear digital-to-analog converter (DAC), whose purity is significantly better than the original DAC output. In addition, with the aid of the low-cost DAC–ADC co-testing method, both DAC and ADC linearity information are accurately obtained with only 1 hit per code. Therefore, it is possible to add DAC linearity information to the DAC input codes, which cancels the nonlinearity of the DAC at output to achieve high purity. The proposed method has been validated by extensive simulation and measurement results, which demonstrated its accuracy and robustness against different resolutions, structures, or performance of the ADCs/DACs. With its low cost and easy test setup, such high-purity sine wave can be widely used for various applications where precision testing is required. In addition, the ADC and DAC linearity information is accurately obtained at the same time without any precision instrumentation, which is suitable for accurate DAC–ADC co-testing.
Auteurs: Yuming Zhuang;Benjamin Magstadt;Tao Chen;Degang Chen;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 02.-2018, volume: 67, issue:2, pages: 279 - 287
Editeur: IEEE
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» High-Q Tuneable 10-GHz Bragg Resonator for Oscillator Applications
Résumé:
This paper describes the design, simulation, and measurement of a tuneable 9.365-GHz aperiodic Bragg resonator. The resonator utilizes an aperiodic arrangement of non ( $lambda $ /4) low-loss alumina plates ( ${mathcal{ E}}_{r}= 9.75$ , loss tangent of $approx 1 times 10^{-5}$ to $2 times 10^{-5}$ ) mounted in a cylindrical metal waveguide. Tuning is achieved by varying the length of the center section of the cavity. A multi-element bellows/probe assembly is presented. A tuning range of 130 MHz (1.39%) is demonstrated. The insertion loss $S_{21}$ varies from −2.84 to −12.03 dB while the unloaded Q varies from 43 788 to 122 550 over this tuning range. At 10 of the 13 measurement points, the unloaded Q exceeds 1 00 000, and the insertion loss is above −7 dB. Two modeling techniques are discussed; these include a simple ABCD circuit model for rapid simulation and optimization and a 2.5-D field solver, which is used to plot the field distribution inside the cavity.
Auteurs: Simon J. Bale;Pratik D. Deshpande;Mark Hough;Stuart J. Porter;Jeremy K. A. Everard;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 281 - 291
Editeur: IEEE
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» High-Quality Soft Video Delivery With GMRF-Based Overhead Reduction
Résumé:
Soft video delivery i.e. analog video transmission has been proposed to provide high video quality in unstable wireless channels. However existing analog schemes need to transmit a significant amount of metadata to a receiver for power allocation and decoding operations causing large overhead and quality degradation due to rate and power losses. To reduce the overhead while keeping the video quality high we propose a new analog transmission scheme. Our scheme exploits a Gaussian Markov random field for modeling video sequences to significantly reduce the required amount of metadata which are obtained by fitting into the Lorentzian function. Our scheme achieves not only reduced overhead but also improved video quality by using the fitting function and parameters for metadata. Evaluations using several test video sequences demonstrate that the proposed scheme reduces overhead by 99.7% with $text{1.2}$-dB improvement of video quality (in terms of peak signal-to-noise ratio) compared to the existing analog video transmission scheme. We also investigate the impact of bandwidth limitation showing a significant gain up to $text{2.7}$  dB for narrow-band systems.
Auteurs: Takuya Fujihashi;Toshiaki Koike-Akino;Takashi Watanabe;Philip V. Orlik;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 473 - 483
Editeur: IEEE
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» High-Resolution RFI Localization Using Covariance Matrix Augmentation in Synthetic Aperture Interferometric Radiometry
Résumé:
Radio frequency interference (RFI) is a significant limiting factor in the retrieval of geophysical parameters measured by microwave radiometers. RFI localization is crucial to mitigate or remove the RFI impacts. In this paper, a novel RFI localization approach using covariance matrix augmentation in synthetic aperture interferometric radiometry (SAIR) is proposed. It utilizes the property of the sparse array configuration, which is commonly used in SAIR, where the sparse array can be viewed as a virtual filled array with much larger number of antenna elements. The approach can be applied in SAIR with a sparse array configuration, such as the European Space Agency Soil Moisture and Ocean Salinity (SMOS) mission. Results on real SMOS data show that, compared with the previous approach, the presented approach has an improved performance of RFI localization with comparable accuracy of localization, such as improved spatial resolution, lower sidelobes, and larger identifiable number of RFIs.
Auteurs: Jun Li;Fei Hu;Feng He;Liang Wu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1186 - 1198
Editeur: IEEE
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» High-Responsivity Si Photodiodes at 1060 nm in Standard CMOS Technology
Résumé:
Photodetection with high responsivity at the wavelength of 1060 nm is highly desirable for light detection and ranging (LiDAR) as well as the recent emergence of swept-source optical coherent tomography (SS-OCT) applications. However, the absorption coefficient $alpha $ of Si material at 1060 nm under the bias of 0 V is very low due to its approach to the absorption bandgap edge of Si material. In this letter, the carrier-collection-enhanced structure is proposed, which functions as multiple carrier collection paths, which enhances the external quantum efficiency of photodiodes. An efficient Si photodiode with responsivity of 0.49 A/W at 1060 nm at 0 V is demonstrated, which is 2.5 times of that of commercial products. The cost-effective fabrication of Si photodiodes greatly enhances the system performance of LiDAR and OCT.
Auteurs: Xia Guo;Qiaoli Liu;Hongyi Zhou;Xinxin Luan;Chong Li;Zonghai Hu;Anqi Hu;Xiaoying He;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 228 - 231
Editeur: IEEE
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» High-Speed InP-Based p-i-n Photodiodes With InGaAs/GaAsSb Type-II Quantum Wells
Résumé:
We present and discuss the performance characteristics of InP-based p-i-n photodiodes (PDs) with InGaAs/GaAsSb type-II multiple quantum wells absorption regions designed to absorb light at mid-infrared wavelengths. Top-illuminated and waveguide-integrated PDs are fabricated with dark currents as low as 100 nA at −2 V, an external responsivity as high as 0.27 A/W at 2 $mu text{m}$ and 0.3 A/W at 1.55 $mu text{m}$ , and a 3-dB bandwidth of 3.5 GHz at 2 $mu text{m}$ .
Auteurs: Bassem Tossoun;Robert Stephens;Ye Wang;Sadhvikas Addamane;Ganesh Balakrishnan;Archie Holmes;Andreas Beling;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:4, pages: 399 - 402
Editeur: IEEE
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» High-Speed Low-Complexity Guided Image Filtering-Based Disparity Estimation
Résumé:
Stereo vision is a methodology to obtain depth in a scene based on the stereo image pair. In this paper, we introduce a discrete wavelet transform (DWT)-based methodology for a state-of-the-art disparity estimation algorithm that resulted in significant performance improvement in terms of speed and computational complexity. In the initial stage of the proposed algorithm, we apply DWT to the input images, reducing the number of samples to be processed in subsequent stages by 50%, thereby decreasing computational complexity and improving processing speed. Subsequently, the architecture has been designed based on this proposed methodology and prototyped on a Xilinx Virtex-7 FPGA. The performance of the proposed methodology has been evaluated against four standard Middlebury Benchmark image pairs viz. Tsukuba, Venus, Teddy, and Cones. The proposed methodology results in the improvement of about 44.4% cycles per frame, 52% frames/s, and 61.5% and 59.6% LUT and register utilization, respectively, compared with state-of-the-art designs.
Auteurs: Charan Kumar Vala;Koushik Immadisetty;Amit Acharyya;Charles Leech;Vibishna Balagopal;Geoff V. Merrett;Bashir M. Al-Hashimi;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 606 - 617
Editeur: IEEE
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» High-Time Resolved Two-Dimensional Tetra-Lateral Position-Sensitive Silicon Photomultiplier
Résumé:
A 2D tetra-lateral position-sensitive silicon photomultiplier (PS-SiPM) has the advantages of high position and photon-number resolutions and only four readout channels for imaging application. However, its time resolution is limited by the position-dependent transmission time-delay effect. In this letter, we report a method to deduct the time jitter caused by transmission time delay and to significantly improve the time resolution of PS-SiPM. Instrument response function of as low as 177.6 ps (full width at half maximum) and position measured error of $44.5 pm 34.5~ mu text{m}$ were obtained at a mean photoelectron number (MPEN) of approximately 14 for the device with active area of $2.77,, text {mm}times 2.77,, text {mm}$ and micro-APD cell number of $277times 277$ . The single photon position resolution was $sim 240.7 ~mu text{m}$ . The position resolution was improved from 214.9 to $19.3~mu text{m}$ when the MPEN increased from 2.3 to 42. Thus, a PS-SiPM with simultaneous high time, position, and photon-number resolutions is realized.
Auteurs: Tianqi Zhao;Yu Peng;Baicheng Li;Ran He;Kun Liang;Ru Yang;Dejun Han;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 232 - 235
Editeur: IEEE
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» Highly Biased Linear Condition Method for Separately Extracting Source and Drain Resistance in MOSFETs
Résumé:
A highly biased linear current method (HBLCM) for separately extracting source and drain resistance ( ${R}_{S}$ and ${R}_{D}$ ) in MOSFETs is proposed. The technique can be applied to a single device by using simple modeling. Compared to other methods, it provides accurate values of ${R}_{S}$ and ${R}_{D}$ because it considers carrier mobility degradation. The method basically uses linear current versus gate voltage ( ${I}_{text {DS}} - {V}_{text {GS}}$ and ${I}_{text {SD}} - {V}_{text {GD}}$ ) characteristics before and after the source/drain interchange ( ${I}_{text {DS}}$ and ${I}_{text {SD}}$ ). Afterward, by using the traditional Y-function and subsequent resistance modeling in a highly biased linear condition, ${R}_{S}$ and ${R}_{D}$ can be separately extracted. In order to evaluate and verify the accuracy of HBLCM, an external resistor was intentionally connected to a source electrode of a device, and the resulting change in source resistance was detected using the proposed method. Moreover, to demonstrate an application of the proposed method, internal resistance deliberately created by hot-carrier injection (HCI) was linked to a drain electrode, thereby changing drain resistance. The changed drain resistance was also sensed by the HBLCM. Af- erward, the HCI-stressed device was cured by electrothermal annealing driven by Joule heating, and the recovery was again clearly observed using the proposed method.
Auteurs: Gun-Hee Kim;Hagyoul Bae;Jae Hur;Choong-Ki Kim;Geon-Beom Lee;Tewook Bang;Yoon-Ik Son;Seong-Wan Ryu;Yang-Kyu Choi;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 419 - 423
Editeur: IEEE
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» Highly Sensitive Optical Detector for Precision Measurement of Coulomb Coupling Strength Based on a Double-Oscillator Optomechanical System
Résumé:
An optomechanical system combining a Coulomb interaction degree of freedom provides a unique platform for precision measurement of electrical charges via the optomechanically induced transparency. A new property of a second-order sideband in a double-oscillator optomechanical system is investigated beyond the conventional linearized description of optomechanical interaction. The results show that the single-second-order sideband will split into the double-second-order sideband under a weak driving field, and the separation of the split second-order sideband shows a strong dependence on the Coulomb coupling strength. Based on the current experimental conditions, such a Coulomb-interaction-induced split of the second-order sideband may enable an all-optical sensor for precision measurement of the Coulomb coupling strength with lower power.
Auteurs: Zeng-Xing Liu;Bao Wang;Cui Kong;Hao Xiong;Ying Wu;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 11
Editeur: IEEE
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» Highly Sensitive Terahertz Gas Sensor Based on Surface Plasmon Resonance With Graphene
Résumé:
One of the most important applications of THz frequencies is biomedical sensing. However, in a THz range, surface plasmon waves on flat metals are not confined and therefore cannot be used for subwavelength sensing. But, it has been shown that graphene can support surface waves at THz frequencies, which has similar properties as plasmonic waves in an optical range. In this paper, a highly sensitive gas sensor in the terahertz frequencies by exciting surface plasmon resonance (SPR) of graphene is proposed. The results show that the proposed SPR gas sensor has high stability and high sensitivity (S), and the highest Smax (∼147°/RIU) has been obtained by optimizing the Fermi energy, the thickness of the dielectric layer, and the incident light frequency. Moreover, the S of the proposed THz sensor for different refractive index (RI) of gas sensing medium (n1) is also discussed.
Auteurs: Yuanjiang Xiang;Jiaqi Zhu;Leiming Wu;Qi You;Banxian Ruan;Xiaoyu Dai;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 7
Editeur: IEEE
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» Highly Sensitive Two-Axis Bending Sensor Based on Arc-Induced Long Period Fiber Grating in Dual Side-Hole Fiber
Résumé:
A highly sensitive two-axis bending sensor based on long period fiber grating (LPFG) in a dual side-hole fiber (DSHF) is presented and experimentally investigated. The LPFG is fabricated by periodically collapsing a piece of DSHF with automatic arc discharge technology. The existence of the two air holes in the DSHF makes the cladding modes, regardless of the polarization state, concentrate in the area perpendicular to the connection of the two holes. Such a feature leads to quite different bending responses at the directions perpendicular and parallel to the connection of the air holes, which makes the DSHF-based LPFG suitable for two-axis bending measurement. The bending sensitivity of the LPFG are 21.03 nm/m-1 and 15.77 dB/m-1 at the orthogonal directions, respectively. Besides, compared with the general arc-induced LPFGs in solid fibers, the size of the DSHF-based LPFG is effectively reduced because the periodic air hole collapse in the DSHF causes a large geometric deformation of the fiber core and increases coupling coefficient between the core and cladding modes. The sensing characteristics of strain, polarization, surrounding refractive index, and temperature are also investigated in our experiment.
Auteurs: Yang Ouyang;Huiyong Guo;Xiaowei Ouyang;Xiaofeng Xu;Ciming Zhou;Ai Zhou;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 9
Editeur: IEEE
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» Highly Sensitive Two-Dimensional Bending Vector Sensor Using an Elliptic Two-Core PCF
Résumé:
A highly sensitive and simple all-fiber interferometric two-dimensional (2D) bending vector sensor is demonstrated. Fiber interferometer works in reflection mode and formed by manually splicing a small section of elliptic two-core photonic crystal fiber at the end of a single-mode fiber. Due to the birefringence nature of the two cores, the fiber device exhibits orientation-dependent bend sensitivity which is different for different polarization states. A high sensitivity of 6.49 nm/mm is achieved for bending along the ${x}$ -direction, and the rms deviations for bending in the $x$ - and ${y}$ -directions are estimated to be 0.015 and 0.098 mm, respectively, by using the matrix method. The device is immune to bend-induced power fluctuation.
Auteurs: Khurram Naeem;Youngjoo Chung;Il-Bum Kwon;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:3, pages: 273 - 276
Editeur: IEEE
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» Hollow Core Antiresonant Fiber With Radially Asymmetric Nodeless Claddings
Résumé:
We propose and numerically study a novel type of hollow core antiresonant fiber with a single layer of nodeless radially asymmetric cladding tubes, i.e., the cladding tube presents a bulb-like shape, that the local cladding curvature radius at the core/cladding boundary is larger than the other side. Compared with counterparts with conventionally used radially symmetric nodeless claddings, e.g., circular and elliptical tubes, numerical analysis shows that such structure can provide excellent broadband low-loss property and robust single-mode guidance. By tuning the local cladding tube curvature radius, the confinement loss characteristic can be less sensitive but the phase matching between core high-order modes (HOMs) and resonant cladding modes can be significantly enhanced than that of the elliptical structure. Since the cladding modal fields are moved closer to those of the core HOMs, the HOM extinction ratio can reach above 104 and maintain over an octave of bandwidth.
Auteurs: Tao-Ying Yu;Xuesong Liu;Zhong-Wei Fan;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 8
Editeur: IEEE
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» Holographic Data Coding: Benchmarking and Extending HEVC With Adapted Transforms
Résumé:
Holography is an emerging technology to represent and display visual information with high expectations in terms of user experience. A hologram is a reproduction of a light field represented through the interference pattern between two wavefields the reference and the object wavefields. Whatever their creation process holograms may have a digital representation using some appropriate format. Moreover considering the huge amounts of data involved digital holographic data have to be compressed using appropriate coding solutions for example available image coding standard solutions or efficient extensions of them. In this context this paper contributes to advance the state-of-the-art on holographic data coding by: 1) benchmarking the most relevant available image coding standard solutions when using the most relevant holographic data representation formats; 2) proposing a novel mode depend directional transform-based HEVC coding solution trained with holographic data. Experimental results obtained under meaningful test conditions show that the proposed coding solution outperforms the state-of-the-art HEVC coding standard for specific formats and conditions. Altogether these two contributions are critical to understand the current status quo and advance the state-of-the-art on holographic data coding.
Auteurs: José Pedro Peixeiro;Catarina Brites;João Ascenso;Fernando Pereira;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 282 - 297
Editeur: IEEE
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» Homeostatic Fault Tolerance in Spiking Neural Networks: A Dynamic Hardware Perspective
Résumé:
Fault tolerance is a remarkable feature of biological systems and their self-repair capability influence modern electronic systems. In this paper, we propose a novel plastic neural network model, which establishes homeostasis in a spiking neural network. Combined with this plasticity and the inspiration from inhibitory interneurons, we develop a fault-resilient robotic controller implemented on an FPGA establishing obstacle avoidance task. We demonstrate the proposed methodology on a spiking neural network implemented on Xilinx Artix-7 FPGA. The system is able to maintain stable firing (tolerance ±10%) with a loss of up to 75% of the original synaptic inputs to a neuron. Our repair mechanism has minimal hardware overhead with a tuning circuit (repair unit) which consumes only three slices/neuron for implementing a threshold voltage-based homeostatic fault-tolerant unit. The overall architecture has a minimal impact on power consumption and, therefore, supports scalable implementations. This paper opens a novel way of implementing the behavior of natural fault tolerant system in hardware establishing homeostatic self-repair behavior.
Auteurs: Anju P. Johnson;Junxiu Liu;Alan G. Millard;Shvan Karim;Andy M. Tyrrell;Jim Harkin;Jon Timmis;Liam J. McDaid;David M. Halliday;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 02.-2018, volume: 65, issue:2, pages: 687 - 699
Editeur: IEEE
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» How Robust Is Your Development Team?
Résumé:
Given the collaborative nature of software development, a robust team is a necessity for project success in both commercial and open source environments. That is, in the event of developers’ absence due to various reasons, how could it potentially disrupt a team’s routine operations? This article offers an automatic approach to intuitively visualize development team hierarchy, quantify overall team robustness, and identify the point (developers) of risk for team robustness. An investigation of six Apache open source projects has shown its effectiveness. This article is part of a special issue on Actionable Analytics for Software Engineering.
Auteurs: Lu Xiao;Zhongyuan Yu;Bohong Chen;Xiao Wang;
Apparue dans: IEEE Software
Date publication: 02.-2018, volume: 35, issue:1, pages: 64 - 71
Editeur: IEEE
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» How to Build PIC-MCC Models for Hall Microthrusters
Résumé:
This paper gives instructions on how to build a 3-D particle-based model of a Hall microthruster. Due to nonequilibrium character induced by low electron thermalization and isotropization rates, presence of different microinstabilities and strong plasma-surface interaction, a multidimensional and kinetic description is necessary. The different modules characterizing the particle-in-cell/Monte Carlo collision cycle are described presenting the last algorithms developed. The model is applied to the study of an SPT20 configuration. Results confirm the importance of a 3-D structure of the discharge with self-organized azimuthal structures. Important deviations from Maxwellian behavior have been detected.
Auteurs: Pierpaolo Minelli;Francesco Taccogna;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 02.-2018, volume: 46, issue:2, pages: 219 - 224
Editeur: IEEE
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» Humanitarian Activities Make a Difference [President's Message]
Résumé:
Presents the President’s message for this issue of the publication.
Auteurs: Tomy Sebastian;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 4 - 5
Editeur: IEEE
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» Hybrid AC/DC Post-Contingency Power-Flow Algorithm Considering Control Interaction of Asynchronous Area
Résumé:
This paper presents an approach for the calculation and estimation of control interactions between asynchronous power systems coupled via multi-terminal high-voltage direct current grids using static analysis methods. This aims at possible application within online security assessment where, as of today, static analysis methods are still a common practice. Therefore, the postcontingency power flow is evaluated using an integrated approach for the solution of AC and DC systems in the power-flow algorithm. Thereby, equations for DC voltage control and AC frequency control of converter stations, generators, loads as well as wind turbines with frequency support are embedded into the extended system Jacobian. The results show that by using the proposed approach, the post-contingency power-flow situation can be accurately determined and the frequency changes in each subsystem can be sufficiently tracked. Using an application example of an offshore power system with frequency support by offshore wind turbines, all results have been validated against dynamic simulation, while simulation models and controllers are provided. It is shown that active power balancing controls of AC and DC systems could have a high impact on line loadings and need to be respected for security analyses.
Auteurs: Tobias Hennig;Lutz Hofmann;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 340 - 348
Editeur: IEEE
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» Hybrid Labels Are the New Measure!
Résumé:
Developing minimum viable products (MVPs) is critical for start-up companies to hit the market fast with an accepted level of performance. The US Food and Drug Administration mandates additional nonfunctional requirements in healthcare systems, meaning that the MVP should provide the best availability, privacy, and security. This critical demand is motivating companies to further rely on analytics to optimize the development process. In a collaborative project with Brightsquid, the authors provided a decision-support system based on analogical reasoning to assist in effort estimation, scoping, and assignment of change requests. This experience report proposes a new metric, change request labels, for better prediction. Using different methods for textual-similarity analysis, the authors found that the combination of machine-learning techniques with experts’ manually added labels has the highest prediction accuracy. Better prediction of change impacts allows a company to optimize its resources and provide proper timing of releases to target MVPs. This article is part of a special issue on Actionable Analytics for Software Engineering.
Auteurs: Maleknaz Nayebi;Shaikh Jeeshan Kabeer;Guenther Ruhe;Chris Carlson;Francis Chew;
Apparue dans: IEEE Software
Date publication: 02.-2018, volume: 35, issue:1, pages: 54 - 57
Editeur: IEEE
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» Hybrid LISA Precoding for Multiuser Millimeter-Wave Communications
Résumé:
Millimeter-wave (mm-wave) communications plays an important role in future cellular networks because of the vast amount of spectrum available in the underutilized mm-wave frequency bands. To overcome the huge free space omnidirectional path loss in those frequency bands, the deployment of a very large number of antenna elements at the base station is crucial. The complexity, power consumption, and costs resulting from the large number of antenna elements can be reduced by limiting the number of RF chains. This leads to hybrid precoding and combining, which, in contrast to the traditional fully digital precoding and combining, moves a part of the signal processing from the digital to the analog domain. This paper proposes new algorithms for the design of hybrid precoders and combiners in a multiuser scenario. The algorithms are based on the previously proposed linear successive allocation method developed for the traditional fully digital version. It successively allocates data streams to users and suppresses the respective interstream interference in two stages, which perfectly matches the hybrid architecture. Furthermore, a low-complexity version is developed by exploiting the typical structure of mm-wave channels. The good performance of the proposed method and its low-complexity version is demonstrated by simulation results.
Auteurs: Wolfgang Utschick;Christoph Stöckle;Michael Joham;Jian Luo;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2018, volume: 17, issue:2, pages: 752 - 765
Editeur: IEEE
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» Hybrid Lithium Iron Phosphate Battery and Lithium Titanate Battery Systems for Electric Buses
Résumé:
Electric buses face problems of short driving range, slow charging, and high cost. To improve the performance of electric buses, a novel hybrid battery system (HBS) configuration consisting of lithium iron phosphate (LFP) batteries and Li-ion batteries with a Li4Ti5O12 (LTO) material anode is proposed. The configuration and control of the HBS are first studied, and a LFP battery degradation model is built. Simulation result indicates that the HBS can help us to mitigate LFP battery degradation. Then, the HBS is optimally sized for electric buses to achieve minimum cost. The daily bus operation and charging patterns as well as LFP battery degradation are considered. The optimal HBS has 10.7% and 19.3% lower total cost than the single LTO-battery and LFP-battery configurations, and has higher range flexibility than the single LTO-battery configuration.
Auteurs: Xiaobin Zhang;Huei Peng;Hewu Wang;Minggao Ouyang;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 02.-2018, volume: 67, issue:2, pages: 956 - 965
Editeur: IEEE
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» Hybrid Particle Swarm Optimization Combined With Genetic Operators for Flexible Job-Shop Scheduling Under Uncertain Processing Time for Semiconductor Manufacturing
Résumé:
Semiconductor manufacturing is a complicated flexible job-shop scheduling problem (FJSP) of combinatorial complexity. Because of the adoption of advanced process control and advanced equipment control, the processing time in advanced wafer fabs become uncertain. Existing approaches considering constant processing time may not be appropriate to address the present problem in a real setting. In practice, processing times can be represented as intervals with the most probable completion time somewhere near the middle of the interval. A fuzzy number that is a generalized interval can represent this processing time interval exactly and naturally. This paper developed a hybrid approach integrating a particle swarm optimization algorithm with a Cauchy distribution and genetic operators (HPSO+GA) for solving an FJSP by finding a job sequence that minimizes the makespan with uncertain processing time. In particular, the proposed hybridized HPSO+GA approach employs PSO for creating operation sequences and assigning the time and resources for each operation, and then uses genetic operators to update the particles for improving the solution. To estimate the validity of the proposed approaches, experiments were conducted to compare the proposed approach with conventional approaches. The results show the practical viability of this approach. This paper concludes with discussions of contributions and recommends directions for future research.
Auteurs: Thitipong Jamrus;Chen-Fu Chien;Mitsuo Gen;Kanchana Sethanan;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2018, volume: 31, issue:1, pages: 32 - 41
Editeur: IEEE
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» Hyperconnected Network: A Decentralized Trusted Computing and Networking Paradigm
Résumé:
With the development of the Internet of Things, a complex CPS system has emerged and is becoming a promising information infrastructure. In the CPS system, the loss of control over user data has become a very serious challenge, making it difficult to protect privacy, boost innovation, and guarantee data sovereignty. In this article, we propose HyperNet, a novel decentralized trusted computing and networking paradigm, to meet the challenge of loss of control over data. HyperNet is composed of the intelligent PDC, which is considered as the digital clone of a human individual; the decentralized trusted connection between any entities based on blockchain as well as smart contract; and the UDI platform, enabling secure digital object management and an identifier-driven routing mechanism. HyperNet has the capability of protecting data sovereignty, and has the potential to transform the current communication-based information system to the future data-oriented information society.
Auteurs: Hao Yin;Dongchao Guo;Kai Wang;Zexun Jiang;Yongqiang Lyu;Ju Xing;
Apparue dans: IEEE Network
Date publication: 02.-2018, volume: 32, issue:1, pages: 112 - 117
Editeur: IEEE
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» I&M in energy efficiency [Trends in Future I&M]
Résumé:
Energy is around us, either from natural origin or created by humankind, and has deeply transformed our lives on how we interact with the environment. We take for granted, mainly in the developed world, its obtainability and almost endless supply. Just an example: we get 325,000 times more light from artificial sources now than at the end of the 19th Century, as any night satellite photo can confirm.
Auteurs: Santiago Barcon;
Apparue dans: IEEE Instrumentation & Measurement Magazine
Date publication: 02.-2018, volume: 21, issue:1, pages: 44 - 45
Editeur: IEEE
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» Identification of Flux Linkage Map of Permanent Magnet Synchronous Machines Under Uncertain Circuit Resistance and Inverter Nonlinearity
Résumé:
This paper proposes a novel scheme for the identification of the whole flux linkage map of permanent magnet synchronous machines, by which the map of dq-axis flux linkages at different load or saturation conditions can be identified by the minimization of a proposed estimation model. The proposed method works on a conventional three-phase inverter based vector control system and the immune clonal based quantum genetic algorithm is employed for the global searching of minimal point. Besides, it is also noteworthy that the influence of uncertain inverter nonlinearity and circuit resistance are cancelled during the modeling process. The proposed method is subsequently tested on two PMSMs and shows quite good performance compared with the finite element prediction results.
Auteurs: Kan Liu;Jianghua Feng;Shuying Guo;Lei Xiao;Zi-Qiang Zhu;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 556 - 568
Editeur: IEEE
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» Identifying Core Concepts of Cybersecurity: Results of Two Delphi Processes
Résumé:
This paper presents and analyzes results of two Delphi processes that polled cybersecurity experts to rate cybersecurity topics based on importance, difficulty, and timelessness. These ratings can be used to identify core concepts–cross-cutting ideas that connect knowledge in the discipline. The first Delphi process identified core concepts that should be learned in any first course on cybersecurity. The second identified core concepts that any cybersecurity professional should know upon graduating from college. Despite the rapidly growing demand for cybersecurity professionals, it is not clear what defines foundational cybersecurity knowledge. Initial data from the Delphi processes lay a foundation for defining the core concepts of the field and, consequently, provide a common starting point to accelerate the development of rigorous cybersecurity education practices. These results provide a foundation for developing evidence-based educational cybersecurity assessment tools that will identify and measure effective methods for teaching cybersecurity. The Delphi results can also be used to inform the development of curricula, learning exercises, and other educational materials and policies.
Auteurs: Geet Parekh;David DeLatte;Geoffrey L. Herman;Linda Oliva;Dhananjay Phatak;Travis Scheponik;Alan T. Sherman;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2018, volume: 61, issue:1, pages: 11 - 20
Editeur: IEEE
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» Identifying the Requirements for Qualified, Unqualified, and Competent Persons Electrical Safety Training
Résumé:
This paper provides an understanding of what constitutes a qualified person, an unqualified person, and a competent person. Also included are the training requirements for each classification. The principles for performing a needs assessment, a job/task analysis, and job hazard analysis are addressed as they relate to the information gathering needed for the development of an effective training program. This gathered information applies to all personnel who are, or may be, exposed to electrical hazards, and who may work on, near, or interact with the electrical systems and equipment.
Auteurs: Dennis K. Neitzel;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 5 - 9
Editeur: IEEE
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» IEC/IEEE 60079-30 Standard, Parts 1 and 2: An Introduction to the Joint Standard for Trace Heating in Explosive Atmospheres
Résumé:
In 2015, the International Electrotechnical Commission (IEC) and the IEEE released the jointly developed standard IEC/IEEE 60079-30, Parts 1 and 2 [1]. The IEE sponsor was the IEE Industry Applications Society (IAS) Petroleum and Chemical Industry Technical Conference (PCIC), and the IEC sponsor was IEC Technical Committee (TC) 31, Equipment for Explosive Atmospheres. The joint development combined the requirements and recommendations of IEEE 515 [2] with IEC 60079-30-1, 2007-01 [3] and IEC 60079-30-2, 2007-01 [4]. This joint development represented the complete harmonization of the international, IEC , and North American certification and design requirements for trace heating in explosive atmospheres. In addition to type tests for product certification, this standard has extensive requirements so that certifying bodies can determine the manufacturer's ability to predict maximum sheath temperatures for trace heaters in explosive atmospheres. This article provides a background for understanding the joint development process and provides an overview of the key technical requirements found in the standards.
Auteurs: Ben C. Johnson;Richard H. Hulett;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2018, volume: 24, issue:1, pages: 32 - 41
Editeur: IEEE
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» IEEE AP-S Chapter News and Activities Planned for 2018 [Chapter News]
Résumé:
Auteurs: Ajay K. Poddar;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 8 - 13
Editeur: IEEE
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» IEEE Student Branch Awards [The Way Ahead]
Résumé:
Presents the recipients of the IEEE Student Branch Awards.
Auteurs: J. Patrick Donohoe;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 4 - 4
Editeur: IEEE
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» Image Autoregressive Interpolation Model Using GPU-Parallel Optimization
Résumé:
With the growth in the consumer electronics industry, it is vital to develop an algorithm for ultrahigh definition products that is more effective and has lower time complexity. Image interpolation, which is based on an autoregressive model, has achieved significant improvements compared with the traditional algorithm with respect to image reconstruction, including a better peak signal-to-noise ratio (PSNR) and improved subjective visual quality of the reconstructed image. However, the time-consuming computation involved has become a bottleneck in those autoregressive algorithms. Because of the high time cost, image autoregressive-based interpolation algorithms are rarely used in industry for actual production. In this study, in order to meet the requirements of real-time reconstruction, we use diverse compute unified device architecture (CUDA) optimization strategies to make full use of the graphics processing unit (GPU) (NVIDIA Tesla K80), including a shared memory and register and multi-GPU optimization. To be more suitable for the GPU-parallel optimization, we modify the training window to obtain a more concise matrix operation. Experimental results show that, while maintaining a high PSNR and subjective visual quality and taking into account the I/O transfer time, our algorithm achieves a high speedup of 147.3 times for a Lena image and 174.8 times for a 720p video, compared to the original single-threaded C CPU code with -O2 compiling optimization.
Auteurs: Jiaji Wu;Long Deng;Gwanggil Jeon;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 426 - 436
Editeur: IEEE
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» Image Class Prediction by Joint Object, Context, and Background Modeling
Résumé:
State-of-the-art image classification methods often use spatial pyramid matching or its variants to make use of the spatial layout of visual features. However, objects may appear at various places with different scales and orientations. Besides, traditionally object-centric-based methods only consider objects and the background without fully exploring the context information. To solve these problems, in this paper we propose a novel image classification method by jointly modeling the object, context, and background information (OCB). OCB consists of three components: 1) locate the positions of objects; 2) determine the context areas of objects; and 3) treat the other areas as the background. We use objectness proposal techniques to select candidate bounding boxes. Boxes with high confidence scores are combined to determine objects’ positions. To select the context areas, we use candidate boxes that have relatively lower confidence scores compared with boxes for object location selection. The other areas are viewed as the background. We jointly combine the object, context, and background for image representation and classification. Experiments on six data sets well demonstrate the superiority of the proposed OCB method over other spatial partition methods.
Auteurs: Chunjie Zhang;Guibo Zhu;Chao Liang;Yifan Zhang;Qingming Huang;Qi Tian;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 428 - 438
Editeur: IEEE
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» Image Classification With Tailored Fine-Grained Dictionaries
Résumé:
In this paper, we propose a novel fine-grained dictionary learning method for image classification. To learn a high-quality discriminative dictionary, three types of multispecific subdictionaries, i.e., class-specific dictionaries (CSDs), universal dictionary (UD), and family-specific dictionaries (FSDs), are simultaneously uncovered. Here, CSDs and UD, respectively, model the patterns for each class and the patterns irrespective of any class. FSDs can help reveal the shared patterns between multiple image classes, by filling the gap between the patterns in CSDs and UD. The dependence among image classes is revealed by the shared FSDs, and a common FSD can be assigned to several classes to represent their residual. Finally, the most discriminative FSD for each class is identified by minimizing the sparse reconstruction error. Extensive experiments are conducted on different widely used data sets for image classification. The results demonstrate the superior performance of the proposed method over some state-of-the-art methods.
Auteurs: Xiangbo Shu;Jinhui Tang;Guo-Jun Qi;Zechao Li;Yu-Gang Jiang;Shuicheng Yan;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2018, volume: 28, issue:2, pages: 454 - 467
Editeur: IEEE
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» Image Encryption Based on Interleaved Computer-Generated Holograms
Résumé:
An encryption method based on interleaved computer-generated holograms (CGHs) displayed by a spatial light modulator (SLM) is demonstrated. Arbitrary decrypted complex optical wave fields are reconstructed in the rear focal plane of two phase-only holograms, generated from original image using a vector decomposition algorithm. Two CGHs are encoded into one hologram by interleaving the column of pixels, which optically combines the optical wave fields of two neighboring phase-only modulated pixels. The designed image encryption system may avoid the inherent silhouette problem and alleviate the precise alignment requirements of interference encryption. Video encryption and real-time dynamic decryption is demonstrated using one SLM.
Auteurs: Dezhao Kong;Liangcai Cao;Xueju Shen;Hao Zhang;Guofan Jin;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 673 - 678
Editeur: IEEE
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» Image-Based Characterization of Alternative Fuel Combustion With Multifuel Burners
Résumé:
Many industrial high-temperature processes such as cement production employ multifuel burners in order to achieve the required energy input with low-cost alternative fuel. So far, a constant operation of multifuel burners with high fractions of alternative fuel (>70%) is not possible due to inherent fluctuating fuel properties. Energy input and product quality are directly affected by varying points of combustion time, different scattering of fuel, and insertion of unburned fuel or chemical substances into the product. We propose an image-processing system based on infrared images that detects the alternative fuel streakline and derives parameters for the characterization of the flight and burning behavior. Using these parameters, an adjustment of the burner settings depending on the fluctuating fuel properties can be carried out. This automatic monitoring and control of the combustion process allows an increased use of alternative fuels in constant operation. Experimental data from a rotary kiln for cement clinker production are used to validate the image-processing system.
Auteurs: Markus Vogelbacher;Patrick Waibel;Jörg Matthes;Hubert B. Keller;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2018, volume: 14, issue:2, pages: 588 - 597
Editeur: IEEE
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» Imaging Corneal Biomechanical Responses to Ocular Pulse Using High-Frequency Ultrasound
Résumé:
Imaging corneal biomechanical changes or abnormalities is important for better clinical diagnosis and treatment of corneal diseases. We propose a novel ultrasound-based method, called ocular pulse elastography (OPE), to image corneal deformation during the naturally occurring ocular pulse. Experiments on animal and human donor eyes, as well as synthetic radiofrequency (RF) data, were used to evaluate the efficacy of the OPE method. Using very high-frequency ultrasound (center frequency = 55 MHz), correlation-based speckle tracking yielded an accuracy of less than 10% error for axial tissue displacements of $0.5~mu text{m}$ or above. Satisfactory speckle tracking was achieved for out-of-plane displacements up to $32~mu text{m}$ . Using synthetic RF data with or without a pre-defined uniform strain, the OPE method detected strains down to 0.0001 axially and 0.00025 laterally with an error less than 10%. Experiments in human donor eyes showed excellent repeatability with an intraclass correlation of 0.98. The measurement outcome from OPE was also shown to be highly correlated with that of standard inflation. These results suggest the feasibility of OPE as a potential clinical tool for evaluating corneal biomechanics in vivo.
Auteurs: Elias Pavlatos;Hong Chen;Keyton Clayson;Xueliang Pan;Jun Liu;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 663 - 670
Editeur: IEEE
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» Immutable Authentication and Integrity Schemes for Outsourced Databases
Résumé:
Database outsourcing enables organizations to offload their data management overhead to the external service providers. Immutable signatures are ideal tools to provide authentication and integrity for such applications with an important property called immutability. Signature immutability ensures that, no attacker can derive a valid signature for unposed queries from previous queries and their corresponding signatures. This prevents an attacker from creating his own de-facto services via such derived signatures. Unfortunately, existing immutable signatures are very computation/communication costly, which make them impractical for real-life applications. In this paper, we developed three new schemes called practical and immutable signature bouquets ( ${PISB}$), which achieve efficient immutability for outsourced databases. ${PISB}$ schemes are simple, non-interactive, and computation/communication efficient. Our generic scheme can be constructed from any aggregate signature coupled with a standard signature. Our specific scheme is constructed from Condensed-RSA and Sequential Aggregate RSA. It has a low verifier computational overhead and compact signature. Our third scheme offers the lowest end-to-end delay among existing alternatives by enabling efficient signature pre-computability. We provide formal security analysis of ${PISB}$  schemes (in Random Oracle Model) and give a theoretical analysis on the relationship between signature immutability and signature extraction. We also showed that ${PISB}$  schemes are more efficient than previous alternatives.
Auteurs: Attila Altay Yavuz;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 02.-2018, volume: 15, issue:1, pages: 69 - 82
Editeur: IEEE
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» Impact of Cross-Sectional Shape on 10-nm Gate Length InGaAs FinFET Performance and Variability
Résumé:
Three cross sections (rectangular, bullet shaped, and triangular), resulting from the fabrication process, of nanoscale In0.53Ga0.47As-on-insulator FinFETs with a gate length of 10.4 nm are modeled using in-house 3-D finite-element density-gradient quantum-corrected drift–diffusion and Monte Carlo simulations. We investigate the impact of the shape on ${I}$ ${V}$ characteristics and on the variability induced by metal grain granularity (MGG), line-edge roughness (LER), and random dopants (RDs) and compared with their combined effect. The more triangular the cross section, the lower the OFF-current, the drain-induced-barrier-lowering, and the subthreshold slope. The ${I}_{ mathrm{scriptscriptstyle ON}}/{I}_{ mathrm{scriptscriptstyle OFF}}$ ratio is three times higher for the triangular-shaped FinFET than for the rectangular-shape one. Independent of the cross section, the MGG variations are the preeminent fluctuations affecting the FinFETs, with four to two times larger $sigma {V}_{T}$ than that from the LER and the RDs, respectively. However, the variability induced threshold voltage ( ${V}_{T}$ ) shift is minimal for the MGG (around 2 mV), but ${V}_{T}$ shift increases 4-fold and 15-fold for the LER and the RDs, respectively. The cross-sectional shape has a very small influence in ${V}_{T}$ and OFF-current of the MGG, LER, and RD variabilities, both separated and in combination, with standard deviatio- differences of only 4% among the different device shapes. Finally, the statistical sum of the three sources of variability can predict simulated combined variability with only a minor overestimation.
Auteurs: Natalia Seoane;Guillermo Indalecio;Daniel Nagy;Karol Kalna;Antonio J. García-Loureiro;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 456 - 462
Editeur: IEEE
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» Impact of Doping Concentration on Electronic Properties of Transition Metal-Doped Monolayer Molybdenum Disulfide
Résumé:
Doping engineering has been an emerging topic in monolayer molybdenum disulfide (mMoS2). However, the dopants used for an n- or p-type device and the effect of doping level are of great interests toward next-generation electronic devices. In this paper, we theoretically reveal the work function tunability of mMoS2 doped by 3d transition metals. We found that the titanium dopant forms a deep-level trap in the midgap of mMoS2 but turning into n-type donor levels in high doping concentration due to the stronger covalent bond and the stable surface morphology, which renders it the widest work function tunability among 3d transition metals. Overall, the n-type behavior is expected by doping with chromium, copper, scandium, and titanium, whereas nickel and zinc dopants lead to the p-type property. The findings feature the selection of dopants for the revolutionary device and highlight the impact of doping levels from the atomistic viewpoint.
Auteurs: Yi-Chia Tsai;Yiming Li;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 733 - 738
Editeur: IEEE
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» Impact of Imperfect CSI on ASER of Hexagonal and Rectangular QAM for AF Relaying Network
Résumé:
In this letter, we derive the closed-form expression of outage probability for a dual-hop variable-gain amplify-and-forward relay network. The maximal ratio combining receiver over independent and non-identically distributed frequency flat Nakagami-m fading channels with integer-valued fading parameter and imperfect channel state information (CSI) is considered. Asymptotic analysis on outage probability is also performed. Average symbol error rate (ASER) expressions are derived for general-order hexagonal and rectangular QAM schemes using the cumulative distribution function-based approach. The impact of the fading parameter and imperfect CSI are highlighted on the system performance. Comparative analysis of ASER performance for different QAM constellations is also illustrated. Monte Carlo simulations are performed to validate the derived analytical results for both perfect and imperfect CSI.
Auteurs: Praveen Kumar Singya;Nagendra Kumar;Vimal Bhatia;
Apparue dans: IEEE Communications Letters
Date publication: 02.-2018, volume: 22, issue:2, pages: 428 - 431
Editeur: IEEE
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» Impact of Power-Electronic Sources on Transmission Line Ground Fault Protection
Résumé:
Power-electronic sources, such as Type 3 wind turbine generators and static synchronous compensators (STATCOM), interface to the grid through, partial- or full-scale, and power converters that have inherently fast switching capability to control their output current during short circuits. The short-circuit current is a function of the specific converter control algorithm and differs significantly from the conventional rotating machine sources without converter interfaces. Therefore, if a transmission-line protection scheme is designed for conventional sources, (not taking into account these differences in short-circuit current characteristics), reliability can be at risk. Using real-life short-circuit currents on lines supplied by sources having a power converter interface, this paper illustrates the reliability risk to conventional line protection schemes, in particular, to those which use negative-sequence quantities for the detection of unbalanced faults. This paper discusses the protection schemes, adopted by BC Hydro–a large Canadian Electric Utility, for transmission lines interconnecting Type 3 wind turbine and STATCOM sources. Their application for ground faults is independent of the converter control algorithm as long as the source is interconnected to the grid via a transformer which is a source of zero-sequence current.
Auteurs: Mukesh Nagpal;Charles Henville;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 62 - 70
Editeur: IEEE
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» Impact of the Gate and Insulator Geometrical Model on the Static Performance and Variability of Ultrascaled Silicon Nanowire FETs
Résumé:
We investigate the effect of the geometrical model adopted for the gate electrode and for the insulator enveloping the access regions on the full-quantum simulation of ultrascaled nanowire FETs (NW-FETs). We compare the results obtained in the “minimal” geometry commonly used in simulations with those obtained in a more realistic one, able to fully account for the gate fringing effects. We evaluate the impact of the model geometry on the static performance of NW-FETs and discuss the interplay with the surface roughness and the random distribution of dopants. We find that the ${I}_{ mathrm{scriptscriptstyle ON}}/{I}_{ mathrm{scriptscriptstyle OFF}}$ ratio evaluated in the minimal geometry can be remarkably underestimated in short devices, notably in the case of small length-to-width ratio. The roughness-induced current degradation and the sensitivity to the surface roughness variability can also suffer from nonnegligible underestimations when evaluated in this geometry. Finally, we point out that an inaccurate description of the device electrostatics is expected to result in an overestimation of the sensitivity to the doping-induced variability.
Auteurs: Demetrio Logoteta;Nicolas Cavassilas;Alessandro Cresti;Marco G. Pala;Marc Bescond;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 424 - 430
Editeur: IEEE
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» Impedance Measures During in vitro Cochlear Implantation Predict Array Positioning
Résumé:
Objective: Improper electrode placement during cochlear implant (CI) insertion can adversely affect speech perception outcomes. However, the intraoperative methods to determine positioning are limited. Because measures of electrode impedance can be made quickly, the goal of this study was to assess the relationship between CI impedance and proximity to adjacent structures. Methods: An Advanced Bionics CI array was inserted into a clear, plastic cochlea one electrode contact at a time in a saline bath (nine trials). At each insertion depth, response to biphasic current pulses was used to calculate access resistance (Ra), polarization resistance (Rp), and polarization capacitance (Cp). These measures were correlated to actual proximity as assessed by microscopy using linear regression models. Results: Impedance increased with insertion depth and proximity to the inner wall. Specifically, Ra increased, Cp decreased, and Rp slightly increased. Incorporating all impedance measures afforded a prediction model (r = 0.88) while optimizing for sub-mm positioning afforded a model with 78.3% specificity. Conclusion: Impedance in vitro greatly changes with electrode insertion depth and proximity to adjacent structures in a predicable manner. Significance : Assessing proximity of the CI to adjacent structures is a significant first step in qualifying the electrode-neural interface. This information should aid in CI fitting, which should help maximize hearing and speech outcomes with a CI. Additionally, knowledge of the relationship between impedance and positioning could have utility in other tissue implants in the brain, retina, or spinal cord.
Auteurs: Christopher Kenneth Giardina;Elliot Samuel Krause;Kanthaiah Koka;Douglas Carl Fitzpatrick;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 327 - 335
Editeur: IEEE
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» Impedance-Based Fault Location Algorithm for Ground Faults in Series-Capacitor-Compensated Transmission Lines
Résumé:
Locating a fault in a series-capacitor-compensated transmission line (SCCTL) is a challenging task due to the action of a metal-oxide varistor a nonlinear element present as a part of the protection system of the series capacitor. In this paper, an accurate fault-location algorithm that uses synchronized measurements from both ends of the SCCTL is presented which provides fault-location results without using the model of MOV or natural fault loop for single-phase-to-ground, and double-phase-to-ground faults. Another salient feature of the proposed technique is that the subroutines for locating faults in different sections transmission line yield almost identical fault-location results regardless of which section the transmission line is faulted. The proposed technique could also be extended to the double-circuit transmission lines. First, the proposed technique is introduced and its features are elaborated through detailed mathematical analysis. Thereafter, a 500-$text{kV}$ system with an SCCTL is designed in PSCAD, while the fault-location algorithm is modeled in MATLAB. The proposed algorithm is tested through simulations covering various fault scenarios in an SCCTL. For performance evaluation, the comparative analysis of the proposed technique with a well-known existing technique is performed in this paper.
Auteurs: Tirath Pal S. Bains;Tarlochan S. Sidhu;Zhihan Xu;Ilia Voloh;Mohammad R. Dadash Zadeh;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 189 - 199
Editeur: IEEE
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» Imperfect Information Dynamic Stackelberg Game Based Resource Allocation Using Hidden Markov for Cloud Computing
Résumé:
Existing static grid resource scheduling algorithms, which are limited to minimizing the makespan, cannot meet the needs of resource scheduling required by cloud computing. Current cloud infrastructure solutions provide operational support at the level of resource infrastructure only. When hardware resources form the virtual resource pool, virtual machines are deployed for use transparently. Considering the competing characteristics of multi-tenant environments in cloud computing, this paper proposes a cloud resource allocation model based on an imperfect information Stackelberg game (CSAM-IISG) using a hidden Markov model (HMM) in a cloud computing environment. CSAM-IISG was shown to increase the profit of both the resource supplier and the applicant. Firstly, we used the HMM to predict the service provider's current bid using the historical resources based on demand. Through predicting the bid dynamically, an imperfect information Stackelberg game (IISG) was established. The IISG motivates service providers to choose the optimal bidding strategy according to the overall utility, achieving maximum profits. Based on the unit prices of different types of resources, a resource allocation model is proposed to guarantee optimal gains for the infrastructure supplier. The proposed resource allocation model can support synchronous allocation for both multi-service providers and various resources. The simulation results demonstrated that the predicted price was close to the actual transaction price, which was lower than the actual value in the game model. The proposed model was shown to increase the profits of service providers and infrastructure suppliers simultaneously.
Auteurs: Wei Wei;Xunli Fan;Houbing Song;Xiumei Fan;Jiachen Yang;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 78 - 89
Editeur: IEEE
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» Improved AlGaN/GaN Metal–Oxide– Semiconductor High-Electron Mobility Transistors With TiO2 Gate Dielectric Annealed in Nitrogen
Résumé:
An AlGaN/GaN metal–oxide–semiconductor high-electron mobility transistor (MOS-HEMT) that uses a high-k TiO2 gate insulator is demonstrated. TiO2 films are annealed at 300 °C and 600 °C in N2 or O2 following the deposition of an oxide layer. Experimental results reveal that the 300 °C N2-annealed TiO2/GaN MOS capacitor has the smallest interface traps of any of the studied devices. The 300 °C N2-annealed oxide interlayers between the GaN and the gate metal reduce the gate leakage current and improve the dc, high-frequency, and noise characteristics. The gate leakage current of the 300 °C N2-annealed MOS-HEMT is more than 3 orders of magnitude less than that of the baseline HEMT. This brief is the first to fabricate a GaN-based MOS-HEMT using an N2-annealed TiO2 gate insulator.
Auteurs: Yu-Shyan Lin;Chi-Che Lu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 783 - 787
Editeur: IEEE
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» Improved Contrast-Enhanced Ultrasound Imaging With Multiplane-Wave Imaging
Résumé:
Contrast-enhanced ultrasound (CEUS) imaging has great potential for use in new ultrasound clinical applications such as myocardial perfusion imaging and abdominal lesion characterization. In CEUS imaging, contrast agents (i.e., microbubbles) are used to improve contrast between blood and tissue because of their high nonlinearity under low ultrasound pressure. However, the quality of CEUS imaging sometimes suffers from a low signal-to-noise ratio (SNR) in deeper imaging regions when a low mechanical index (MI) is used to avoid microbubble disruption, especially for imaging at off-resonance transmit frequencies. In this paper, we propose a new strategy of combining CEUS sequences with the recently proposed multiplane-wave (MW) compounding method to improve the SNR of CEUS in deeper imaging regions without increasing MI or sacrificing frame rate. The MW-CEUS method emits multiple Hadamard-coded CEUS pulses in each transmission event (i.e., pulse-echo event). The received echo signals first undergo fundamental bandpass filtering (i.e., the filter is centered on the transmit frequency) to eliminate the microbubble’s second-harmonic signals because they cannot be encoded by pulse inversion. The filtered signals are then Hadamard decoded and realigned in fast time to recover the signals as they would have been obtained using classic CEUS pulses, followed by designed recombination to cancel the linear tissue responses. The MW-CEUS method significantly improved contrast-to-tissue ratio and SNR of CEUS imaging by transmitting longer coded pulses. The image resolution was also preserved. The microbubble disruption ratio and motion artifacts in MW-CEUS were similar to those of classic CEUS imaging. In addition, the MW-CEUS sequence can be adapted to other transmission coding formats. These properties of MW-CEUS can potentially facilitate CEUS imaging for many clinical applications, especially assessing deep abdominal organs or the heart.
Auteurs: Ping Gong;Pengfei Song;Shigao Chen;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 178 - 187
Editeur: IEEE
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» Improved Estimation for Well-Logging Problems Based on Fusion of Four Types of Kalman Filters
Résumé:
The concept of information fusion has gained a widespread interest in many fields due to its complementary properties. It makes systems more robust against uncertainty. This paper presents a new approach for the well-logging estimation problem by using a fusion methodology. The natural gamma-ray tool (NGT) is considered as an important instrument in the well logging. The NGT detects changes in natural radioactivity emerging from the variations in concentrations of micronutrients as uranium (U), thorium (Th), and potassium (K). The main goal of this paper is to have precise estimation of the concentrations of $U$ , $Th$ , and $K$ . Four types of Kalman filters are designed to estimate the elements using the NGT sensor. Then, a fusion of the Kalman filters is utilized into an integrated framework by an ordered weighted averaging (OWA) operator to enhance the quality of the estimations. A real covariance of the output error based on the innovation matrix is utilized to design weighting factors for the OWA operator. The simulation studies indicate not only a reliable performance of the proposed method compared with the individual Kalman filters but also a better response in contrast with previous fusion methodologies.
Auteurs: Sina Soltani;Mojtaba Kordestani;Paknoosh Karim Aghaee;Mehrdad Saif;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 647 - 654
Editeur: IEEE
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» Improved Frequency Regulation in an Islanded Mixed Source Microgrid Through Coordinated Operation of DERs and Smart Loads
Résumé:
The advent of microgrids paved the way for energy decentralization and self-sufficiency among consumers. Reciprocating engine-driven synchronous generators (also known as gensets) are one of the most commonly found distributed energy resources (DERs) installed in a microgrid. A key concern in microgrid operation is the frequency regulation, especially when it is islanded from the main grid. In recent years, the inverter-based DERs have witnessed huge growth. When fast-responding inverter-based DERs are working in parallel with the slow-acting gensets within the islanded mixed source microgrid, many challenges exist in coordinating their operation. In particular, an inverter-based DER is susceptible to collapse due to its large transient loading and this can bring down the entire system. This paper investigates load sharing and proposes new techniques for improved frequency regulation in an islanded mixed source microgrid. An improved coordination scheme between DERs is presented in this paper by accounting for their inertial and governor response characteristics. The unequal transient load sharing between gensets and inverter-based DERs is redistributed to prevent system collapse as well as achieve desired frequency regulation. For dealing with extreme scenarios, a smart load shedding scheme is integrated into the coordinated operation of DERs.
Auteurs: Abrez Mondal;Mahesh S. Illindala;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 112 - 120
Editeur: IEEE
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» Improved Optimal Route Evaluation Method for Wireless Sensor Networks
Résumé:
It is well known that both a “minimal energy consuming path” and “balanced communication load among the nodes” are necessary criteria for route evaluation. To achieve acceptable performance, these two requirements must be well balanced. To provide this balance, we propose an improved optimal route evaluation method based on the principal component approach for wireless sensor networks. This method ensures a diversified evaluation and prompt dynamic load balance in different network monitoring environments. Further, the weighting factor of each evaluation indicator can be estimated using the principal component approach. This method can avoid the problem of requiring manual selection of weight factors based on experience, which lacks guidance based on scientific theories, is subjective, and may negatively affect evaluation precision. Comparison with other state-of-the-art algorithms confirms that the proposed evaluation function improves the performance of a network significantly.
Auteurs: Kui Liu;Chunfeng Wang;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1747 - 1754
Editeur: IEEE
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» Improved Prosthetic Control Based on Myoelectric Pattern Recognition via Wavelet-Based De-Noising
Résumé:
Real-time inference of human motor volition has great potential for the intuitive control of robotic devices. Toward this end, myoelectric pattern recognition (MPR) has shown promise in the control of prosthetic limbs. Interfering noise and susceptibility to motion artifacts have hindered the use of MPR outside controlled environments, and thus represent an obstacle for clinical use. Advanced signal processing techniques have been previously proposed to improve the robustness of MPR systems. However, the investigation of such techniques have been limited to offline implementations with long time windows, which makes real-time use unattainable. In this work, we present a novel algorithm using discrete and stationary wavelet transforms for MPR that can be executed in real-time. Our wavelet-based de-noising algorithm outperformed conventional band-pass filtering (up to 100 Hz) and improved real-time MPR in the presence of motion artifacts, as measured by the motion test. Improved signal-to-noise ratio was found not to be crucial in offline MPR, as machine learning algorithms can integrate high but consistent noise as part of the signal. However, varying interference is expected to occur in real life where signal processing algorithms, as the one introduced in this paper, would potentially have a positive impact. Furthermore implementation of these algorithms in a prosthetic embedded system is required to validate their feasibility and usability during activities of the daily living.
Auteurs: Julian Maier;Adam Naber;Max Ortiz-Catalan;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 506 - 514
Editeur: IEEE
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» Improved Responsivity Drop From 250 to 200 nm in Sputtered Gallium Oxide Photodetectors by Incorporating Trace Aluminum
Résumé:
A solar-blind photodetector (PD) based on the cosputtered aluminum–gallium oxide (AGO) material after thermal annealing at 900 °C has been demonstrated using a metal–semiconductor–metal structure. By incorporating optimum trace aluminum (Al), the AGO PD shows the peak responsivity (at 230 nm) of 1.38 A/W under a bias voltage of 5 V, which is 53.61 times greater than that of the PD from the gallium oxide (GO) film without incorporating any Al content. The photocurrent, dark current, and detectivity (at 5 V and 230 nm) of AGO PD are also improved to be 46.4, 0.83, and 96.5 times, respectively, greater than those of GO one. Unlike conventional GO samples revealing obvious drop in spectral response from 250 to 200 nm, the AGO PD with an Al/(Al + Ga) ratio of 1.8% exhibits a nearly flat responsivity curve in the deep ultraviolet region. This improvement is significant compared with previous reports for the GO and AGO PDs by other growth methods.
Auteurs: Shuo-Huang Yuan;Chao-Chun Wang;Shiau-Yuan Huang;Dong-Sing Wuu;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 220 - 223
Editeur: IEEE
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» Improved Subthreshold Swing and Short Channel Effect in FDSOI n-Channel Negative Capacitance Field Effect Transistors
Résumé:
Negative capacitance (NC) FETs with channel lengths from 30 nm to $50~mu text{m}$ , gated with ferroelectric hafnium zirconium oxide are fabricated on fully depleted silicon-on-insulator (FDSOI) substrates. Enhanced capacitance due to NC, hysteresis-free operation, and improved subthreshold slope are observed. The NC effect leads to enhancement of drain current for small voltage operation. In addition, improved short channel performance is demonstrated owing to the reverse drain induced barrier lowering characteristics of the NC operation.
Auteurs: Daewoong Kwon;Korok Chatterjee;Ava J. Tan;Ajay K. Yadav;Hong Zhou;Angada B. Sachid;Roberto Dos Reis;Chenming Hu;Sayeef Salahuddin;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 300 - 303
Editeur: IEEE
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» Improved Super-Resolution Ultrasound Microvessel Imaging With Spatiotemporal Nonlocal Means Filtering and Bipartite Graph-Based Microbubble Tracking
Résumé:
Super-resolution ultrasound microvessel imaging with contrast microbubbles has recently been proposed by multiple studies, demonstrating outstanding resolution with high potential for clinical applications. This paper aims at addressing the potential noise issue in in vivo human super-resolution imaging with ultrafast plane-wave imaging. The rich spatiotemporal information provided by ultrafast imaging presents features that allow microbubble signals to be separated from background noise. In addition, the high-frame-rate recording of microbubble data enables the implementation of robust tracking algorithms commonly used in particle tracking velocimetry. In this paper, we applied the nonlocal means (NLM) denoising filter on the spatiotemporal domain of the microbubble data to preserve the microbubble tracks caused by microbubble movement and suppress random background noise. We then implemented a bipartite graph-based pairing method with the use of persistence control to further improve the microbubble signal quality and microbubble tracking fidelity. In an in vivo rabbit kidney perfusion study, the NLM filter showed effective noise rejection and substantially improved microbubble localization. The bipartite graph pairing and persistence control demonstrated further noise reduction, improved microvessel delineation, and a more consistent microvessel blood flow speed measurement. With the proposed methods and freehand scanning on a free-breathing rabbit, a single microvessel cross-sectional profile with full-width at half-maximum of $57~mu text{m}$ could be imaged at approximately 2-cm depth (ultrasound transmit center frequency = 8 MHz, theoretical spatial resolution $sim 200~mu text{m}$ ). Cortical microvessels that are $7- ~mu text{m}$ apart can also be clearly separated. These results suggest that the proposed methods have good potential in facilitating robust in vivo clinical super-resolution microvessel imaging.
Auteurs: Pengfei Song;Joshua D. Trzasko;Armando Manduca;Runqing Huang;Ramanathan Kadirvel;David F. Kallmes;Shigao Chen;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 02.-2018, volume: 65, issue:2, pages: 149 - 167
Editeur: IEEE
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» Improved Synapse Device With MLC and Conductance Linearity Using Quantized Conduction for Neuromorphic Systems
Résumé:
In this letter, we demonstrate the conductive-bridging RAM (CBRAM) with excellent multi-level cell (MLC) and linear conductance characteristics for an artificial synaptic device of neuromorphic systems. Our findings show that inherent characteristics of CBRAM can achieve the linear conductance and MLC characteristics as a product of an integer unit of the conductance. However, uncontrolled metal-ion injection into the switching layer results in a significant degradation of device uniformity, leading to degradation in the classification accuracy. Thus, we introduce a multi-layer CBRAM configuration (Cu/HfO2/Ta/Cu2S/W) to control the ionic motion in electrolytes. As a result of device engineering, highly improved classification accuracy is achieved using CIFAR-10 data set.
Auteurs: Seokjae Lim;Changhyuck Sung;Hyungjun Kim;Taesu Kim;Jeonghwan Song;Jae-Joon Kim;Hyunsang Hwang;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 312 - 315
Editeur: IEEE
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» Improved Visualization of Gastrointestinal Slow Wave Propagation Using a Novel Wavefront-Orientation Interpolation Technique
Résumé:
Objective: High-resolution mapping of gastrointestinal (GI) slow waves is a valuable technique for research and clinical applications. Interpretation of high-resolution GI mapping data relies on animations of slow wave propagation, but current methods remain as rudimentary, pixelated electrode activation animations. This study aimed to develop improved methods of visualizing high-resolution slow wave recordings that increases ease of interpretation. Methods: The novel method of “wavefront-orientation” interpolation was created to account for the planar movement of the slow wave wavefront, negate any need for distance calculations, remain robust in atypical wavefronts (i.e., dysrhythmias), and produce an appropriate interpolation boundary. The wavefront-orientation method determines the orthogonal wavefront direction and calculates interpolated values as the mean slow wave activation-time (AT) of the pair of linearly adjacent electrodes along that direction. Stairstep upsampling increased smoothness and clarity. Results: Animation accuracy of 17 human high-resolution slow wave recordings (64–256 electrodes) was verified by visual comparison to the prior method showing a clear improvement in wave smoothness that enabled more accurate interpretation of propagation, as confirmed by an assessment of clinical applicability performed by eight GI clinicians. Quantitatively, the new method produced accurate interpolation values compared to experimental data (mean difference 0.02 ± 0.05 s) and was accurate when applied solely to dysrhythmic data (0.02 ± 0.06 s), both within the error in manual AT marking (mean 0.2 s). Mean interpolation processing time was 6.0 s per wave. Conclusion and Significance: These novel methods provide a validated visualization platform that will improve analysis of high-resolution GI mapp- ng in research and clinical translation.
Auteurs: Terence P. Mayne;Niranchan Paskaranandavadivel;Jonathan C. Erickson;Gregory O'Grady;Leo K. Cheng;Timothy R. Angeli;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 02.-2018, volume: 65, issue:2, pages: 319 - 326
Editeur: IEEE
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» Improvement of Energy Transfer in a Cavity-Type 915-MHz Microwave Plasma Source
Résumé:
An improvement in the energy transfer in a cavity-type microwave plasma source (MPS) operated at 915 MHz by a better design of the device, capable of ensuring a high microwave power coupling from the supply line to the sustained plasma was a goal of this paper. Our approach was twofold. First, numerical simulations of an electromagnetic field distribution inside a typical cavity-type MPS were carried out. The standard model of homogeneous plasma generated by the MPS and the two-port method was combined. This enabled estimating the concentration $n_{e}$ and collisions frequency $nu $ of electrons in the plasma. Based on these data, a more energy efficient MPS could be designed. Second, to verify the numerical prediction, a modified version of the MPS was built and the improvement in the MPS energy efficiency was proved experimentally.
Auteurs: Robert Miotk;Mariusz Jasiński;Jerzy Mizeraczyk;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2018, volume: 66, issue:2, pages: 711 - 716
Editeur: IEEE
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» Improvement of Power Quality by Using Advanced Reactive Power Compensation
Résumé:
In the same feeder, it will decline the power quality of power supply when the quality is poor at load side, which can cause other equipment malfunction and even damage devices. Therefore, a reactive power compensation method is suggested to improve the power quality of the electric arc furnace in a distribution power system. Both the static var compensator (SVC) and an active filter can modify power factor and balance three phase currents simultaneously. The active filter can solve the problem of instantaneous state of an SVC. Then, an SVC can reduce power quantity of the active filter. Finally, field measurement data in a metal factory were analyzed. Simulation results confirmed the feasibility of correcting the power factor and balancing load currents simultaneously using the proposed method.
Auteurs: Yu-Wei Liu;Shiuan-Hau Rau;Chi-Jui Wu;Wei-Jen Lee;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 18 - 24
Editeur: IEEE
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» Improvement of Reflection Detection Success Rate of GNSS RO Measurements Using Artificial Neural Network
Résumé:
Global Navigation Satellite System (GNSS) radio occultation (RO) has been widely used in the prediction of weather, climate, and space weather, particularly in the area of tropospheric analyses. However, one of the issues with GNSS RO measurements is that they are interfered with by the signals reflected from the earth’s surface. Many RO events are subject to such interfered GNSS measurements, which are considerably difficult to extract from the GNSS RO measurements. To precisely identify interfered RO events, an improved machine learning approach—a gradient descent artificial neural network (ANN)-aided radio-holography method—is proposed in this paper. Since this method is more complex than most other machine learning methods, for improving its efficiency through the reduction in computational time for near-real-time applications, a scale factor and a regularization factor are also adjusted in the ANN approach. This approach was validated using Constellation Observing System for Meteorology, Ionosphere, and Climate/FC-3 atmPhs (level 1b) data during the period of day of year 172–202, 2015, and its detection results were compared with the flag data set provided by Radio Occultation Meteorology Satellite Application Facilities for the performance assessment and validation of the new approach. The results were also compared with those of the support vector machine method for improvement assessment. The comparison results showed that the proposed method can considerably improve both the success rate of GNSS RO reflection detection and the computational efficiency.
Auteurs: Andong Hu;Suqin Wu;Xiaoming Wang;Yan Wang;Robert Norman;Changyong He;Han Cai;Kefei Zhang;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 760 - 769
Editeur: IEEE
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» Improvement of Threshold Voltage Reliability of 4H-SiC MOSFETs With Lanthanum Silicate by High Temperature Forming Gas Anneal
Résumé:
We report the effect of a high-temperature forming gas anneal (FGA) on the electrical characteristics and threshold voltage (VT) instability of high-mobility Si-face (0001) 4H-SiC metal oxide semiconductor field effect transistors (MOSFETs) with lanthanum silicate (LaSiOx). The MOSFET with LaSiOx after 800 °C FGA in 5% H2 and 95% N2 mixture shows significantly reduced VT shift under 3-MV/cm positive bias stressing from 2.78 to 1.65 V, while maintaining high field-effect mobility of 122.7 cm2/Vs and sufficiently positive VT of 2.76 V.
Auteurs: Xiangyu Yang;Bongmook Lee;Veena Misra;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2018, volume: 39, issue:2, pages: 244 - 247
Editeur: IEEE
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» Improving Grid Power Availability in Rural Telecom Exchanges
Résumé:
India has seen a huge surge in the telecom sector with total rural telecom subscribers doubling from 200.81 million to 404.16 million between 2010 and 2015. Therefore, telecom exchanges are built throughout the country to support this development. With severe electric power shortages in rural India, it poses a challenge to power these exchanges. It is observed that power supply in rural areas is not always available in three phase and can sometimes be available in two or single phase depending on fault in the three-phase system. Currently, used power plants in telecom exchanges are not designed to adapt to these variable input phase conditions. In this paper, a method is proposed to modify the currently used power plants such that they easily adapt to variable input phase conditions. This will lead to the utmost utilization of grid power and save valuable diesel fuel used in back-up diesel generators. The proposed method is designed and verified to have reasonable input power quality as per international standards. A quantitative estimation of diesel savings is also presented to estimate the percentage of diesel savings as a function of power outage.
Auteurs: Santanu Mishra;Abhishek Maji;Soumya Shubhra Nag;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 02.-2018, volume: 54, issue:1, pages: 636 - 646
Editeur: IEEE
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» Improving Land Surface Temperature and Emissivity Retrieval From the Chinese Gaofen-5 Satellite Using a Hybrid Algorithm
Résumé:
Land surface temperature (LST) is a key surface feature parameter. Temperature and emissivity separation (TES) and split-window (SW) algorithms are two typical LST estimation algorithms that have been applied to a variety of sensors to generate LST products. The TES algorithm can synchronously obtain LST and emissivity, but it requires high accuracy for atmospheric correction of the thermal infrared (TIR) data and does not perform well for surfaces with low spectral emissivity contrast. On the contrary, the SW algorithm can retrieve LST without detailed atmospheric data because the linear or nonlinear combination of brightness temperatures in the two adjacent TIR channels can reduce the atmospheric effect; however, this algorithm requires prior accurate pixel emissivity. Combining the two algorithms can improve the accuracy of LST estimation because the emissivity calculated from the TES algorithm can be used in the SW algorithm, and the LST from the SW algorithm can then be applied to the TES algorithm as an initial value to refine emissivity and LST. This paper investigates the aforementioned hybrid algorithm using Chinese Gaofen-5 satellite data, which will provide four-channel data for TIR at 40 m for synchronously retrieving LST and emissivity. The results showed that the hybrid algorithm was less sensitive to instrument noise and atmospheric data error, and can obtain LST and emissivity with an error less than 1 K and 0.015, respectively, which is better than those obtained with the single TES or SW algorithm. Finally, the hybrid algorithm was tested in simulated image and ground-measured data, and obtained accurate results.
Auteurs: Huazhong Ren;Xin Ye;Rongyuan Liu;Jiaji Dong;Qiming Qin;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2018, volume: 56, issue:2, pages: 1080 - 1090
Editeur: IEEE
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» Improving Multipath Video Transmission With Raptor Codes in Heterogeneous Wireless Networks
Résumé:
Supported by the latest technical innovations mobile users are able to simultaneously receive real-time streaming services with different radio access technologies (e.g. LTE and Wi-Fi). The stream control transmission protocol (SCTP) is a vitally important transport protocol to enable concurrent multipath transfer (CMT) in heterogeneous wireless networks with multihomed terminals. However enabling CMT of real-time video streaming to multihomed mobiles is challenged with key technical dilemmas: 1) high-quality real-time video transmission is constrained by stringent requirements in delay and throughput; 2) wireless networks are bandwidth-limited and error-prone; and 3) the congestion control and packet retransmission modules in the SCTP may incur frequent deadline violations and throughput fluctuations. Motivated by addressing these challenging problems this research proposes a Video and Raptor code aware CMT (CMT-VR) solution. First we develop a mathematical model to formulate the utility maximization problem of multipath real-time video delivery over parallel wireless networks. Second we present a transmission framework that includes online packet scheduling Raptor coding adaptation and retransmission control algorithms. CMT-VR is distinct from the existing SCTPs in leveraging the video frame priority and rateless Raptor coding. The performance verification is conducted by means of system evaluations over real wireless networks and extensive semiphysical emulations in the Exata platform. Evaluation results demonstrate that CMT-VR achieves appreciable improvements over the reference schemes in perceived video quality goodput and end-to-end delay.
Auteurs: Jiyan Wu;Bo Cheng;Ming Wang;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 02.-2018, volume: 20, issue:2, pages: 457 - 472
Editeur: IEEE
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» Improving Small-Signal Stability of an MMC With CCSC by Control of the Internally Stored Energy
Résumé:
The dc-side dynamics of modular multilevel converters (MMCs) can be prone to poorly damped oscillations or stability problems when the second-harmonic components of the arm currents are mitigated by a circulating current suppression controller (CCSC). This paper demonstrates that the source of these oscillations is the uncontrolled interaction of the dc-side current and the internally stored energy of the MMC, as resulting from the CCSC. Stable operation and improved performance of the MMC control system can be ensured by introducing the closed-loop control of the energy and the dc-side current. The presented analysis relies on a detailed state-space model of the MMC, which is formulated to obtain constant variables in steady state. The resulting state-space equations can be linearized to achieve a linear time invariant model, allowing for eigenvalue analysis of the small-signal dynamics of the MMC. Participation factor analysis is utilized to identify the source of the poorly damped dc-side oscillations, and indicates the suitability of introducing control of the internal capacitor voltage or the corresponding stored energy. An MMC connected to a dc power source with an equivalent capacitance, and operated with dc voltage droop in the active power flow control, is used as an example for the presented analysis. The developed small-signal models and the improvement in small-signal dynamics achieved by introducing control of the internally stored energy are verified by time-domain simulations in comparison to an electro-magnetic transient (EMT) simulation model of an MMC with 400 submodules per arm.
Auteurs: Julian Freytes;Gilbert Bergna;Jon Are Suul;Salvatore D’Arco;François Gruson;Frédéric Colas;Hani Saad;Xavier Guillaud;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 429 - 439
Editeur: IEEE
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» Improving the Diversity of Faculty in Electrical and Computer Engineering (iREDEFINE ECE)
Résumé:
As women faculty in electrical and computer engineering (ECE), we have been involved in several efforts targeted at increasing the participation of women in ECE departments. For example, at Rutgers University, we have organized presentations and workshops for first year students that highlighted the societal aspects of ECE, such as bioelectrical engineering applications. Such focus did bear fruit; between 2010 and 2016, the sophomore female enrollment in ECE at Rutgers rose from 11% to 19%. At the University of San Diego, we have conducted research on the demographics and outcomes of undergraduate students in ECE, facilitated workshops to help faculty teach in more inclusive ways, and are currently working on a National Science Foundation (NSF)-funded effort to revolutionize engineering education [1]. Also, as chairs, we have been considering ways to diversify our faculty carefully considering the overall hiring process including innovative approaches such as cluster hires [2], paying close attention to the language used when advertising faculty positions, the discussions during the review of the candidates, the candidate selection criteria, and the interview process [3]. However, the number of diverse graduate students is small to begin with, and in an era in which companies have realized the value of diversity, academia has to compete with companies such as Google and Microsoft for the best Ph.D. graduates. Without a diverse faculty, we cannot sustain a diverse student body.
Auteurs: Athina Petropulu;Susan Lord;
Apparue dans: Proceedings of the IEEE
Date publication: 02.-2018, volume: 106, issue:2, pages: 214 - 218
Editeur: IEEE
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» Improving the SSD Performance by Exploiting Request Characteristics and Internal Parallelism
Résumé:
With the explosive growth in the data volume, the I/O bottleneck has become an increasingly daunting challenge for big data analytics. It is urgent and important to introduce high-performance flash-based solid state drives (SSDs) into the storage systems. However, since the existing systems are primarily designed for conventional magnetic hard disk drives, directly incorporating SSDs in the existing systems cannot fully exploit SSDs’ performance advantages. In this paper, we propose a new I/O scheduler for SSDs, namely Amphibian, that exploits the high-level request characteristics and low-level parallelism of flash chips to improve the performance of SSD-based storage systems. Amphibian includes two performance enhancement schemes: 1) size-based request ordering, which prioritizes requests with small sizes in processing and 2) garbage collection (GC)-aware request dispatching that delays issuing requests to flash chips that are in the GC state. These two schemes employed in Amphibian significantly reduce the average waiting times of the requests from the host. Our extensive evaluation results derived from three types of SSDs show that, compared with the existing I/O schedulers, Amphibian greatly improves both throughput and average response times for SSD-based storage systems, thus improving the I/O performance of the systems.
Auteurs: Bo Mao;Suzhen Wu;Lide Duan;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 02.-2018, volume: 37, issue:2, pages: 472 - 484
Editeur: IEEE
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» Improving TMPA 3B43 V7 Data Sets Using Land-Surface Characteristics and Ground Observations on the Qinghai–Tibet Plateau
Résumé:
The accurate knowledge of precipitation information over the Qinghai–Tibet Plateau, where the rain gauge networks are limited, is vital for various applications. While satellite-based precipitation estimates provide high spatial resolution (0.25°), large uncertainties and systematic anomalies still exist over this critical area. To derive more accurate monthly precipitation estimates, a spatial data-mining algorithm was used to remove the obvious anomalies compared with their neighbors from the original Tropical Rainfall Measuring Mission (TRMM) multisatellite precipitation analysis (TMPA) 3B43 V7 data at an annual scale, as the TMPA data are more accurate than other satellite-based precipitation estimates. To supplement the international exchange stations, additional ground observations were used to calibrate and improve the TMPA data with anomalies removed at an annual scale. Finally, a disaggregation strategy was adopted to derive monthly precipitation estimates based on the calibrated TMPA data. We concluded that: 1) the obvious anomalies compared with their neighbors could be removed from the original TMPA data sets and 2) the calibrated results were of a higher quality than the original TMPA data in each month from 2000 to 2013. The improved TMPA 3B43 V7 data sets over the Qinghai–Tibet plateau, named NITMPA3B43_QTP, are available at http://agri.zju.edu.cn/NITMPA3B43_QTP/.
Auteurs: Ziqiang Ma;Lianqing Zhou;Wu Yu;Yuanyuan Yang;Hongfeng Teng;Z. Shi;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 02.-2018, volume: 15, issue:2, pages: 178 - 182
Editeur: IEEE
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» IMS2017 Student Design Competition Results
Résumé:
Presents information on the IMS2017 Student Design Competition.
Auteurs: Robert Caverly;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 67 - 68
Editeur: IEEE
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» IMU-Based Wrist Rotation Control of a Transradial Myoelectric Prosthesis
Résumé:
This paper describes a control method intended to facilitate improved control of a myoelectric prosthesis containing a wrist rotator. Rather than exclusively utilizing electromyogram (EMG) for the control of all myoelectric components (e.g., a hand and a wrist), the proposed controller utilizes inertial measurement (from six-axis inertial measurement unit (IMU)) to sense upper arm abduction/adduction, and uses this input to command a wrist rotation velocity. As such, the controller essentially substitutes shoulder abduction/adduction in place of agonist/antagonist EMG to control wrist angular velocity, which preserves EMG for control of the hand (or other arm components). As a preliminary assessment of efficacy, the control method was implemented on a transradial prosthesis prototype with a powered wrist rotator and hand, and experimentally assessed on five able-bodied subjects who wore the prototype using an able-bodied adaptor and one transradial amputee subject while performing assessments representative of activities of daily living. The assessments compared the (timed) performance of the combined EMG/ IMU-based control method with a (conventional) sequential EMG control approach. Results of the assessment indicate that the able-bodied subjects were able to perform the tasks 33% faster on average with the EMG/IMU-based method, relative to a conventional sequential EMG method. The same assessment was subsequently conducted using a single transradial amputee subject, which resulted in similar performance trends, although with a somewhat lessened effect size—specifically, the amputee subject was on average 22% faster in performing tasks with the IMU-based controller.
Auteurs: Daniel A. Bennett;Michael Goldfarb;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 02.-2018, volume: 26, issue:2, pages: 419 - 427
Editeur: IEEE
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» In Vivo Characterization of a Wireless Telemetry Module for a Capsule Endoscopy System Utilizing a Conformal Antenna
Résumé:
This paper describes the design, fabrication, packaging, and performance characterization of a conformal helix antenna created on the outside of a $text{10 mm}times ,text{30 mm}$ capsule endoscope designed to operate at a carrier frequency of 433 MHz within human tissue. Wireless data transfer was established between the integrated capsule system and an external receiver. The telemetry system was tested within a tissue phantom and in vivo porcine models. Two different types of transmission modes were tested. The first mode, replicating normal operating conditions, used data packets at a steady power level of 0 dBm, while the capsule was being withdrawn at a steady rate from the small intestine. The second mode, replicating the worst-case clinical scenario of capsule retention within the small bowel, sent data with stepwise increasing power levels of –10, 0, 6, and 10 dBm, with the capsule fixed in position. The temperature of the tissue surrounding the external antenna was monitored at all times using thermistors embedded within the capsule shell to observe potential safety issues. The recorded data showed, for both modes of operation, a low error transmission of 10−3 packet error rate and 10−5 bit error rate and no temperature increase of the tissue according to IEEE standards.
Auteurs: Julia Faerber;Gerard Cummins;Sumanth Kumar Pavuluri;Paul Record;Adrian R. Ayastuy Rodriguez;Holly S. Lay;Rachael McPhillips;Benjamin F. Cox;Ciaran Connor;Rachael Gregson;Richard Eddie Clutton;Sadeque Reza Khan;Sandy Cochran;Marc P. Y. Desmulliez;
Apparue dans: IEEE Transactions on Biomedical Circuits and Systems
Date publication: 02.-2018, volume: 12, issue:1, pages: 95 - 105
Editeur: IEEE
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» Inadequate Software Testing Can Be Disastrous [Essay]
Résumé:
Writing code is just one part of the software development lifecycle. The testing phase occurs at the end of the process, but it is equally important. Testing uncovers errors and verifies software; it provides an opportunity to fix problems and make improvements. Unfortunately, testing is sometimes overlooked, and software errors occur. Activision learned this difficult lesson when it failed to fully test its video game. Recent history has shown that even more disastrous results can occur from inadequate software testing.
Auteurs: Edwin Torres;
Apparue dans: IEEE Potentials
Date publication: 02.-2018, volume: 37, issue:1, pages: 9 - 47
Editeur: IEEE
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» Incentive Mechanism and Rating System Design for Crowdsourcing Systems: Analysis, Tradeoffs and Inference
Résumé:
Macrotasking crowdsourcing systems like Elance and Fiverr serve as efficient platforms for requesters to outsource challenging and innovative tasks that require special skills to workers. It is widely practiced in such systems that requesters reward workers based on requesters’ assessment on solution quality. The challenge is that requesters’ assessment may not be accurate to reflect the intrinsic quality of a solution due to human factors like personal preferences or biases. In this work, we consider answering the following questions: How to design a mechanism to incentivize workers provide high quality solutions in the presence of such human factors? How to formally study the impact of human factors on workers’ financial incentive to participate? We design a mechanism to incentivize workers to provide high-quality contributions, which is robust to human factors. Our incentive mechanism consists of a “task bundling scheme” and a “rating system”, which reward workers based on requesters’ rating on the solution quality. We propose a probabilistic model to capture human factors, and quantify their impact on the incentive mechanism. We formulate an optimization framework to select appropriate rating system parameters, which can be viewed as a tradeoff between “system efficiency”, i.e., the total number of tasks can be solved given a fixed reward budget, and the “rating system complexity”, which determines the human cognitive cost and time in expressing ratings. We also formulate an optimization framework to select appropriate bundling size, which can tradeoff system efficiency against service delay (i.e., the waiting time to form a task bundle). Finally, we con- uct experiments on a dataset from Elance. Experimental results show that our incentive mechanism achieves at least 99.95 percent of the theoretical maximum system efficiency with a service delay of at most 2.3639 hours. Furthermore, we discover that the rating system in Elance is too complex, and it should be simplified to a binary rating system (i.e., two rating points).
Auteurs: Hong Xie;John C. S. Lui;
Apparue dans: IEEE Transactions on Services Computing
Date publication: 02.-2018, volume: 11, issue:1, pages: 90 - 102
Editeur: IEEE
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» Incorporation of Prior Knowledge of Signal Behavior Into the Reconstruction to Accelerate the Acquisition of Diffusion MRI Data
Résumé:
Diffusion MRI data are generally acquired using hyperpolarized gases during patient breath-hold, which yields a compromise between achievable image resolution, lung coverage, and number of $b$ -values. In this paper, we propose a novel method that accelerates the acquisition of diffusion MRI data by undersampling in both the spatial and $b$ -value dimensions and incorporating knowledge about signal decay into the reconstruction (SIDER). SIDER is compared with total variation (TV) reconstruction by assessing its effect on both the recovery of ventilation images and the estimated mean alveolar dimensions (MADs). Both methods are assessed by retrospectively undersampling diffusion data sets ( $n $ =8) of healthy volunteers and patients with Chronic Obstructive Pulmonary Disease (COPD) for acceleration factors between x2 and x10. TV led to large errors and artifacts for acceleration factors equal to or larger than x5. SIDER improved TV, with a lower solution error and MAD histograms closer to those obtained from fully sampled data for acceleration factors up to x10. SIDER preserved image quality at all acceleration factors, although images were slightly smoothed and some details were lost at x10. In conclusion, we developed and validated a novel compressed sensing method for lung MRI imaging and achieved high acceleration factors, which can be used to increase the amount of data acquired during breath-hold. This methodology is expected to improve the accuracy of estimated lung microstructure dimensions and provide more options in the study of lung diseases with MRI.
Auteurs: Juan F. P. J. Abascal;Manuel Desco;Juan Parra-Robles;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2018, volume: 37, issue:2, pages: 547 - 556
Editeur: IEEE
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» Indented Antenna Arrays for High Isolation: The Growing Interest in Simultaneous-Transmit-and-Receive-Based Full-Duplex Communication Systems
Résumé:
In full-duplex communication systems, reflections of transmitted waves as a result of the antenna mismatch may leak into the receiver and create strong on-site interferences. Such reflections cannot be suppressed by conventional frontend isolation techniques even with ideal circulators. Indented antenna arrays are thus proposed to destructively combine the reflection from each antenna element and prevent them from negatively impacting the receiver sensitivity. The essential idea is to break the symmetry between the transmitting and receiving paths by using an antenna aperture that is curved by indenting the antenna elements. Because of this asymmetry, all of the elements contribute to the wave transmission and reception in phase, whereas the reflections from those elements are out of phase and cancel each other out. With indented antenna configurations, broadband isolation between the transmitting and receiving paths can be achieved for both monostatic and bistatic antenna settings. The improvement is obtained without sacrificing antenna radiation patterns or polarizations. Measured results with a four-element indented quasi-Yagi antenna array operating from 3.2 to 3.4 GHz are presented. The results have demonstrated a 13-dB improvement on the antenna return loss of a single array, a 15-dB transmit/receive isolation improvement in a monostatic array, including circulators, and a 20-dB transmit/receive isolation improvement for a bistatic array without using circulators.
Auteurs: Qiang Xu;Mathew Biedka;Yuanxun Ethan Wang;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 72 - 80
Editeur: IEEE
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» Independently Tunable Ultrasharp Double Fano Resonances in Coupled Plasmonic Resonator System
Résumé:
A coupled plasmonic resonator system is investigated by both the finite element method (FEM) and the multimode interference coupled-mode theory (MICMT). The resonator system is made up of a cross rectangular cavity on two metal–insulator–metal (MIM) waveguides separated by a metal baffle. The asymmetric cross rectangular in the structure induces an additional Fano resonance in the transmission spectrum, which only single Fano resonance arises in the structure consisted of the symmetric cross-rectangular cavities. The positions of double Fano resonances in the transmission spectrum can be manipulated independently by changing the size of the horizontal rectangular cavity. It is of great help for designing photonic component at fixed wavelengths. The proposed structure based on our independently tunable double Fano resonances has a wide application in the sensors, splitters, switches, and nano-photonic integrated circuits devices.
Auteurs: Hongxue Fu;Shilei Li;Yilin Wang;Gang Song;Pengfei Zhang;Lulu Wang;Li Yu;
Apparue dans: IEEE Photonics Journal
Date publication: 02.-2018, volume: 10, issue:1, pages: 1 - 9
Editeur: IEEE
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» Index-Based Network Aligner of Protein-Protein Interaction Networks
Résumé:
Network Alignment over graph-structured data has received considerable attention in many recent applications. Global network alignment tries to uniquely find the best mapping for a node in one network to only one node in another network. The mapping is performed according to some matching criteria that depend on the nature of data. In molecular biology, functional orthologs, protein complexes, and evolutionary conserved pathways are some examples of information uncovered by global network alignment. Current techniques for global network alignment suffer from several drawbacks, e.g., poor performance and high memory requirements. We address these problems by proposing IBNAL, Indexes-Based Network ALigner, for better alignment quality and faster results. To accelerate the alignment step, IBNAL makes use of a novel clique-based index and is able to align large networks in seconds. IBNAL produces a higher topological quality alignment and comparable biological match in alignment relative to other state-of-the-art aligners even though topological fit is primarily used to match nodes. IBNAL’s results confirm and give another evidence that homology information is more likely to be encoded in network topology than sequence information.
Auteurs: Ahed Elmsallati;Abdulghani Msalati;Jugal Kalita;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 330 - 336
Editeur: IEEE
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» Induced Eddy Currents in Simple Conductive Geometries: Mathematical Formalism Describes the Excitation of Electrical Eddy Currents in a Time-Varying Magnetic Field
Résumé:
A complete mathematical formalism is introduced to describe the excitation of electrical eddy currents due to a time-varying magnetic field. The process works by applying a quasistatic approximation to Ampere's law and then segregating the magnetic field into impressed and induced terms. The result is a nonhomogeneous vector Helmholtz equation that can be analytically solved for many practical geometries. Four demonstration cases are then solved under a constant excitation field over all space.
Auteurs: James R. Nagel;
Apparue dans: IEEE Antennas and Propagation Magazine
Date publication: 02.-2018, volume: 60, issue:1, pages: 81 - 88
Editeur: IEEE
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» Inferring the Functions of Proteins from the Interrelationships between Functional Categories
Résumé:
This study proposes a new method to determine the functions of an unannotated protein. The proteins and amino acid residues mentioned in biomedical texts associated with an unannotated protein $p$ can be considered as characteristics terms for $p$ , which are highly predictive of the potential functions of $p$ . Similarly, proteins and amino acid residues mentioned in biomedical texts associated with proteins annotated with a functional category $f$ can be considered as characteristics terms of $f$ . We introduce in this paper an information extraction system called IFP_IFC that predicts the functions of an unannotated protein $p$ by representing $p$ and each functional category $f$ by a vector of weights. Each weight reflects the degree of association between a c- aracteristic term and $p$ (or a characteristic term and $f$ ). First, IFP_IFC constructs a network, whose nodes represent the different functional categories, and its edges the interrelationships between the nodes. Then, it determines the functions of $p$ by employing random walks with restarts on the mentioned network. The walker is the vector of $p$ . Finally, $p$ is assigned to the functional categories of the nodes in the network that are visited most by the walker. We evaluated the quality of IFP_IFC by comparing it experimentally with two other systems. Results showed marked improvement.
Auteurs: Kamal Taha;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 157 - 167
Editeur: IEEE
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» Inferring Unknown Biological Function by Integration of GO Annotations and Gene Expression Data
Résumé:
Characterizing genes with semantic information is an important process regarding the description of gene products. In spite that complete genomes of many organisms have been already sequenced, the biological functions of all of their genes are still unknown. Since experimentally studying the functions of those genes, one by one, would be unfeasible, new computational methods for gene functions inference are needed. We present here a novel computational approach for inferring biological function for a set of genes with previously unknown function, given a set of genes with well-known information. This approach is based on the premise that genes with similar behaviour should be grouped together. This is known as the guilt-by-association principle. Thus, it is possible to take advantage of clustering techniques to obtain groups of unknown genes that are co-clustered with genes that have well-known semantic information (GO annotations). Meaningful knowledge to infer unknown semantic information can therefore be provided by these well-known genes. We provide a method to explore the potential function of new genes according to those currently annotated. The results obtained indicate that the proposed approach could be a useful and effective tool when used by biologists to guide the inference of biological functions for recently discovered genes. Our work sets an important landmark in the field of identifying unknown gene functions through clustering, using an external source of biological input. A simple web interface to this proposal can be found at http://fich.unl.edu.ar/sinc/webdemo/gamma-am/.
Auteurs: Guillermo Leale;Ariel Emilio Bayá;Diego H. Milone;Pablo M. Granitto;Georgina Stegmayer;
Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Date publication: 02.-2018, volume: 15, issue:1, pages: 168 - 180
Editeur: IEEE
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» Influencing Sources for Dark Current Transport and Avalanche Mechanisms in Planar and Mesa HgCdTe p-i-n Electron-Avalanche Photodiodes
Résumé:
In this paper, both planar and mesa homojunction p-i-n HgCdTe electron-avalanche photodiodes (e-APDs) are fabricated and investigated to better understand the dark current transport and electron-avalanche mechanisms of the devices and optimize the structures. The experiment results are agreed well by simulated ${I}$ ${V}$ characteristics based on established numerical models. Our results show that the multiplication region fabrication process leads to enormous characteristic difference between planar and mesa diodes. Shockley–Read–Hall and trap-assisted tunneling current are the main components of dark current for the planar/mesa junction under low bias voltage, and dark current is mainly influenced by band-to-band tunneling and avalanche current when higher reverse bias is added. In addition, we found that the difference between the uniformity of the electric field distributions in multiplication regions is the primary reason for the differences of the dark current. It was also proved that the dark current of planar e-APDs is dramatically affected by the junction corners, and mesa e-APDs dark current is found to be greatly dependent on the multiplication region thickness. Our work provides a great deal of theoretical basis for dark current formation and the avalanche mechanism of HgCdTe e-APDs.
Auteurs: Qing Li;Jiale He;Weida Hu;Lu Chen;Xiaoshuang Chen;Wei Lu;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 02.-2018, volume: 65, issue:2, pages: 572 - 576
Editeur: IEEE
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» InGaP/AlGaInP Quantum Well Discrete Mode Laser Diode Emitting at 689 nm
Résumé:
A discrete-mode laser diode, fabricated in the In0.6Ga0.4P/AlGaInP multiple quantum well system, emitting a single mode at $lambda =689$ nm is reported. The laser has an ex-facet output power >10 mW at 30 °C and operates mode hop free in the temperature range 0 °C to 50 °C.
Auteurs: Richard Phelan;Michael Gleeson;Diarmuid Byrne;John O’Carroll;Philip Long;Lina Maigyte;Robert Lennox;Kevin Carney;Chris Herbert;Jim Somers;Brian Kelly;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2018, volume: 30, issue:3, pages: 235 - 237
Editeur: IEEE
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» Instrumentation and measurement testing in the real-time lab for automation of complex power systems
Résumé:
This paper presents an overview of the portion of the real-time simulation laboratory of the Institute for Automation of Complex Power Systems at RWTH Aachen University, dedicated to the testing of instrumentation, measurement and monitoring applications. Its key feature is the ability to test monitoring systems and complex monitoring methods as integrated systems as well as a set of individual components. This is made possible by testing platforms that accommodate a mix of interoperable real and real-time simulated components and include communications, databases, and protocols that are representative of the field deployment of the monitoring system.
Auteurs: Ferdinanda Ponci;Abhinav Sadu;Robert Uhl;Markus Mirz;Andrea Angioni;Antonello Monti;
Apparue dans: IEEE Instrumentation & Measurement Magazine
Date publication: 02.-2018, volume: 21, issue:1, pages: 17 - 24
Editeur: IEEE
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» Integrated HVDC Circuit Breakers With Current Flow Control Capability
Résumé:
Two key problems in meshed high-voltage direct current (HVDC) transmission grids are managing line power flows and protection against dc faults. Current flow controllers (CFCs) will be required to balance cable currents in meshed dc grids, in order to prevent individual line power capacity limits restricting overall power flow in the grid. Direct current circuit breakers (DCCBs) will be also required to protect HVDC grids from dc faults. This paper demonstrates that the current flow controller functionality can be added into a hybrid CB's design. This paper proposes integrating an interline CFC into the load commutation switch (LCS) of a hybrid DCCB. The integrated design LCS/CFC is analyzed and a state-space model is derived. The control of the CFC is designed and the performance of the LCS/CFC during normal operation is verified by means of MATLAB Simulink and PSCAD simulations. A comparison of the integrated LCS/CFC and the separate design is given. The case studies show a reduction in total power losses, and improved protection operation times can be achieved.
Auteurs: Oliver Cwikowski;Joan Sau-Bassols;Bin Chang;Eduardo Prieto-Araujo;Mike Barnes;Oriol Gomis-Bellmunt;Roger Shuttleworth;
Apparue dans: IEEE Transactions on Power Delivery
Date publication: 02.-2018, volume: 33, issue:1, pages: 371 - 380
Editeur: IEEE
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» Integrated Polarized Skylight Sensor and MIMU With a Metric Map for Urban Ground Navigation
Résumé:
This paper presents a novel multi-sensor navigation system for the urban ground vehicle. The integration system can combine the measurements from a polarized skylight sensor, an inertial sensor, and a monocular camera. Utilizing the polarized skylight sensor, we propose a robust orientation algorithm with the total least squares to provide the orientation constraint for the integrating system. In our algorithm, the ambiguity problem of polarized orientation is solved without any other sensor. In order to enhance the algorithm’s robustness in the urban environment, we also propose a real-time method that uses the gradient of the degree of the polarization to remove the obstacles. With a monocular camera, we build a metric map and recognize places in the map to provide the position constraint for the integrating system. We develop the Kalman filter to integrate these constraints with the inertial navigation results to estimate the orientation and position for the ground vehicle. The results demonstrate that our proposed system outperforms other vision-based navigation algorithms–the RMSE of the position error is 2.04 m (0.01% of the travelled distance) and the RMSE of the orientation error is 0.84°. Finally, we present interesting insights gained with respect to the further work in sensors and robotics.
Auteurs: Chen Fan;Xiaoping Hu;Xiaofeng He;Lilian Zhang;Junxiang Lian;
Apparue dans: IEEE Sensors Journal
Date publication: 02.-2018, volume: 18, issue:4, pages: 1714 - 1722
Editeur: IEEE
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» Integrated Systems-in-Package: Heterogeneous Integration of Millimeter-Wave Active Circuits and Passives in Fan-Out Wafer-Level Packaging Technologies
Résumé:
Recent advances in silicon semiconductor technology with transit and maximum oscillation frequencies above 300 GHz have enabled the integration of complex transceiver front ends operating in the millimeter-wave (mmW) regime for a variety of applications. Among these, the most prominent frequency ranges (and their associated applications) are currently the 60-GHz short-range communication frequency band [1]-[2] and E-band wireless back-haul solutions [3]-[4], as well as the 76-81-GHz band for automotive radar sensor realizations [5]-[6].
Auteurs: Amelie Hagelauer;Maciej Wojnowski;Klaus Pressel;Robert Weigel;Dietmar Kissinger;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2018, volume: 19, issue:1, pages: 48 - 56
Editeur: IEEE
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