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Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 11

» Statistical Analysis for Pattern-Dependent Simultaneous Switching Outputs (SSO) of Parallel Single-Ended Buffers
Abstract:
Switching currents of simultaneous switching output (SSO) buffers can cause significant power-supply-induced jitter (PSIJ) and uncertainty in the output voltages. The bit error rate (BER) can be simulated by considering all possible input data patterns with a long data sequence; however, it requires large computational efforts. In this paper, the SSO waveforms are analytically calculated, including the rise time of the input voltage, and the probability density functions (PDFs) of the waveforms are analytically calculated. The PDFs of the SSO step responses are combined with the inter-symbol interference (ISI) PDF extraction. The statistical eye and BER eye diagrams obtained from the proposed method are validated with HSPICE simulations. The effects of the SSO patterns as well as the channel ISI are successfully included in the proposed method. Also, the effects of input rise time and the number of parallel SSO buffers are investigated, and the proposed method is extended for analysis of SSO buffers with the data bus inversion (DBI) coding. The method should be practically useful for design of wideband memory I/O interfaces and low-cost consumer devices by reducing the computational time of the jitter and BER drastically.
Autors: Jingook Kim;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 156 - 169
Publisher: IEEE
 
» Stochastic Look-Ahead Economic Dispatch With Variable Generation Resources
Abstract:
With the continuing growth of renewable penetration in power systems, it becomes increasingly challenging to manage the operational uncertainty at near-real-time stage via deterministic scheduling approaches. This paper explores the necessity, benefits and implementability of applying stochastic programming to security constrained economic dispatch (SCED). We formulate a stochastic look-ahead economic dispatch (LAED-S) model for near-real-time power system operation. A concept of uncertainty responses is introduced to assess the power system economic risk with respect to net load uncertainties. This concept offers the system operator a simple yet effective gauge to decide whether a stochastic approach is more desirable than a deterministic one. For an efficient stochastic dispatch algorithm, an innovative hybrid computing architecture is proposed. It leverages the progressive hedging algorithm and the L-shaped method. Numerical experiments are conducted on a practical 5889-bus system to illustrate the effectiveness of the proposed approach.
Autors: Yingzhong Gu;Le Xie;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 17 - 29
Publisher: IEEE
 
» Stochastic Multistage Coplanning of Transmission Expansion and Energy Storage
Abstract:
Transmission expansion and energy storage increase the flexibility of power systems and, hence, their ability to deal with uncertainty. Transmission lines have a longer lifetime and a more predictable performance than energy storage, but they require a very large initial investment. While battery energy storage systems (BESS) can be built faster and their capacity can be increased gradually, their useful life is shorter because their energy capacity degrades with time and each charge and discharge cycle. Additional factors, such as the expected profiles of load and renewable generation significantly affect planning decisions. This paper proposes a stochastic, multistage, coplanning model of transmission expansion, and BESS that considers both the delays in transmission expansion and the degradation in storage capacity under different renewable generation and load increase scenarios. The proposed model is tested using a modified version of the IEEE-RTS. Sensitivity analyses are performed to assess how factors such as the planning method, the storage chemistry characteristics, the current transmission capacity, and the uncertainty on future renewable generation and load profiles affect the investment decisions.
Autors: Ting Qiu;Bolun Xu;Yishen Wang;Yury Dvorkin;Daniel S. Kirschen;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 643 - 651
Publisher: IEEE
 
» Stochastic Multiview Hashing for Large-Scale Near-Duplicate Video Retrieval
Abstract:
Near-duplicate video retrieval (NDVR) has been a significant research task in multimedia given its high impact in applications, such as video search, recommendation, and copyright protection. In addition to accurate retrieval performance, the exponential growth of online videos has imposed heavy demands on the efficiency and scalability of the existing systems. Aiming at improving both the retrieval accuracy and speed, we propose a novel stochastic multiview hashing algorithm to facilitate the construction of a large-scale NDVR system. Reliable mapping functions, which convert multiple types of keyframe features, enhanced by auxiliary information such as video-keyframe association and ground truth relevance to binary hash code strings, are learned by maximizing a mixture of the generalized retrieval precision and recall scores. A composite Kullback–Leibler divergence measure is used to approximate the retrieval scores, which aligns stochastically the neighborhood structures between the original feature and the relaxed hash code spaces. The efficiency and effectiveness of the proposed method are examined using two public near-duplicate video collections and are compared against various classical and state-of-the-art NDVR systems.
Autors: Yanbin Hao;Tingting Mu;Richang Hong;Meng Wang;Ning An;John Y. Goulermas;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 1 - 14
Publisher: IEEE
 
» Stochastic Point-to-Point Iterative Learning Tracking Without Prior Information on System Matrices
Abstract:
This paper contributes to a point-to-point iterative learning control problem for stochastic systems without prior information on system matrices. The stochastic approximation technique with gradient estimation by random difference is introduced to design the update law for input. It is strictly proved that the input sequence would converge almost surely to the optimal one, which minimizes the averaged tracking performance index. An illustrative simulation shows the effectiveness of the proposed algorithm.
Autors: Dong Shen;Jian Han;Youqing Wang;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 376 - 382
Publisher: IEEE
 
» Stopping Rule-Based Iterative Tree Search for Low-Complexity Detection in MIMO Systems
Abstract:
Breadth first tree search (BFTS) algorithms are known to provide a close to maximum likelihood (quasi-ML) solution at a low-complexity if the received sequence is detected in the right sequence order. However, finding the right sequence order has an exponential overhead. In view of this, we propose to repeatedly apply a BFTS algorithm to all sequence orders. Since it will test all the orders, it is expected to achieve quasi-ML performance. However, this will increase the complexity because of redundant iterations. The complexity can be reduced if we can stop the iterations as soon as a quasi-ML solution is achieved. For this, we propose two stopping rules, one relies on a constellation based heuristic and the other one uses the distribution of ML cost. It is found that their complexity curves have a cross-over point. Thus, a combination of the two rules provides a quasi-ML error performance at a low-complexity for uncoded as well as coded systems. We further show that the proposed stopping rule can reduce the complexity of depth first tree search algorithms also. Last, for large MIMO systems, compared with existing algorithms, it is found to be exceptionally better in terms of both error performance and complexity.
Autors: Abhay Kumar Sah;A. K. Chaturvedi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 169 - 179
Publisher: IEEE
 
» Stratified Decision Forests for Accurate Anatomical Landmark Localization in Cardiac Images
Abstract:
Accurate localization of anatomical landmarks is an important step in medical imaging, as it provides useful prior information for subsequent image analysis and acquisition methods. It is particularly useful for initialization of automatic image analysis tools (e.g. segmentation and registration) and detection of scan planes for automated image acquisition. Landmark localization has been commonly performed using learning based approaches, such as classifier and/or regressor models. However, trained models may not generalize well in heterogeneous datasets when the images contain large differences due to size, pose and shape variations of organs. To learn more data-adaptive and patient specific models, we propose a novel stratification based training model, and demonstrate its use in a decision forest. The proposed approach does not require any additional training information compared to the standard model training procedure and can be easily integrated into any decision tree framework. The proposed method is evaluated on 1080 3D high-resolution and 90 multi-stack 2D cardiac cine MR images. The experiments show that the proposed method achieves state-of-the-art landmark localization accuracy and outperforms standard regression and classification based approaches. Additionally, the proposed method is used in a multi-atlas segmentation to create a fully automatic segmentation pipeline, and the results show that it achieves state-of-the-art segmentation accuracy.
Autors: Ozan Oktay;Wenjia Bai;Ricardo Guerrero;Martin Rajchl;Antonio de Marvao;Declan P. O’Regan;Stuart A. Cook;Mattias P. Heinrich;Ben Glocker;Daniel Rueckert;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 332 - 342
Publisher: IEEE
 
» Streaming Mobile Cloud Gaming Video Over TCP With Adaptive Source–FEC Coding
Abstract:
Cloud gaming has emerged as a promising application to enable high-end game playing with thin clients. Transmission control protocol (TCP) is pervasively adopted as the transport-layer protocol in the mainstream cloud gaming systems for video communication. However, streaming mobile cloud gaming video using the TCP is challenged with several key technical barriers: 1) the performance limitations of wireless networks in bandwidth and reliability; 2) the high throughput demand and stringent delay constraint imposed by high-quality gaming video transmission; and 3) the deadline violations and throughput fluctuations caused by the packet retransmission and congestion control mechanisms in the TCP. To address these critical problems, this paper proposes an application-layer source–forward error correction (FEC) coding framework dubbed adaptive source–FEC coding over TCP (ESCOT). First, we analytically formulate the optimization problem of joint source–FEC coding to minimize the end-to-end distortion of real-time video communication over TCP. Second, we develop a heuristic solution for effective loss rate approximation, source rate control, and FEC coding adaptation. ESCOT is distinct from existing source–FEC coding schemes in proactively analyzing and leveraging the TCP characteristics. The proposed solution is able to effectively mitigate both consecutive and sporadic video frame drops caused by congestion and random packet losses. We conduct the performance evaluation through extensive emulations in the Exata platform using real-time gaming video encoded by the H.264 codec. Experimental results show that the ESCOT advances the state of the art with noticeable improvements in video peak signal-to-noise ratio, end-to-end delay, goodput, and frame success rate.
Autors: Jiyan Wu;Chau Yuen;Ngai-Man Cheung;Junliang Chen;Chang Wen Chen;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jan 2017, volume: 27, issue:1, pages: 32 - 48
Publisher: IEEE
 
» Strong Converse Rates for Quantum Communication
Abstract:
We revisit a fundamental open problem in quantum information theory, namely, whether it is possible to transmit quantum information at a rate exceeding the channel capacity if we allow for a non-vanishing probability of decoding error. Here, we establish that the Rains information of any quantum channel is a strong converse rate for quantum communication. For any sequence of codes with rate exceeding the Rains information of the channel, we show that the fidelity vanishes exponentially fast as the number of channel uses increases. This remains true even if we consider codes that perform classical post-processing on the transmitted quantum data. As an application of this result, for generalized dephasing channels, we show that the Rains information is also achievable, and thereby establish the strong converse property for quantum communication over such channels. Thus, we conclusively settle the strong converse question for a class of quantum channels that have a non-trivial quantum capacity.
Autors: Marco Tomamichel;Mark M. Wilde;Andreas Winter;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 715 - 727
Publisher: IEEE
 
» Strong Secrecy for Cooperative Broadcast Channels
Abstract:
A broadcast channel (BC) where the decoders cooperate via a one-sided link is considered. One common and two private messages are transmitted and the private message to the cooperative user should be kept secret from the cooperation-aided user. The secrecy level is measured in terms of strong secrecy, i.e., a vanishing information leakage. An inner bound on the capacity region is derived by using a channel-resolvability-based code that double-bins the codebook of the secret message, and by using a likelihood encoder to choose the transmitted codeword. The inner bound is shown to be tight for semi-deterministic and physically degraded BCs, and the results are compared with those of the corresponding BCs without a secrecy constraint. Blackwell and Gaussian BC examples illustrate the impact of secrecy on the rate regions. Unlike the case without secrecy, where sharing information about both private messages via the cooperative link is optimal, our protocol conveys parts of the common and non-confidential messages only. This restriction reduces the transmission rates more than the usual rate loss due to secrecy requirements. An example that illustrates this loss is provided.
Autors: Ziv Goldfeld;Gerhard Kramer;Haim H. Permuter;Paul Cuff;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 469 - 495
Publisher: IEEE
 
» Structured Identification of Reduced-Order Models of Power Systems in a Differential-Algebraic Form
Abstract:
In a recent paper, we proposed a system identification method for constructing reduced-order models for the electro-mechanical dynamics of large power systems, divided into multiple coherent clusters, using Synchrophasors. Every cluster in the actual model was represented as an aggregate generator in the reduced-order model. An aggregate network graph connected one aggregate generator to another. In this paper, we extend this identification approach to differential-algebraic (DAE) models. First, every cluster is associated with a unique terminal bus, referred to as the pilot bus, that couples its internal network to the rest of the system. The proposed algorithm uses Synchrophasor measurements from the pilot buses to identify the dynamic model of the aggregate generator for each cluster using nonlinear least squares while retaining the identity of all the pilot buses. The resulting reduced-order model is in the form of a nonlinear electric circuit described by aggregate differential and algebraic equations. We illustrate our results using two case studies, one for the IEEE 9-bus power system and another for the IEEE 39-bus power system. We also discuss how these reduced-order DAE models may be useful for designing shunt controllers at the pilot buses by using Synchrophasor feedback.
Autors: Seyedbehzad Nabavi;Aranya Chakrabortty;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 198 - 207
Publisher: IEEE
 
» Students Interacting with Working Engineers [The Way Ahead]
Abstract:
Autors: J. Patrick Donohoe;
Appeared in: IEEE Potentials
Publication date: Jan 2017, volume: 36, issue:1, pages: 4 - 4
Publisher: IEEE
 
» Students' Design Project Series: Sharing Experiences [SP Education]
Abstract:
Autors: Hana Godrich;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 82 - 88
Publisher: IEEE
 
» Study on Operation of a Surface-Wave Oscillator Around the $pi$ -Point Region
Abstract:
We numerically and experimentally studied the operation of a W-band (75–110 GHz) surface-wave oscillator driven by the electron beam energy of less than 100 keV. Two numerical methods of the real wavenumber analysis and the saddle point analysis are studied to examine the operation of the oscillator. We analyzed the Cherenkov instability for the interaction of the space charge modes and the structure modes EH01. We showed that the instabilities are of absolute instabilities when the oscillator operates around the -point region. In the experiment, radiations due to the absolute instability are detected around the -point region when the length of the slow-wave structure (SWS) is short enough. On the other hand, the absolute instability generates no meaningful radiation in the -point region for the long length of SWS.
Autors: Min Thu San;Kazuo Ogura;Kiyoyuki Yambe;Yuta Annaka;Junpei Fujita;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 30 - 38
Publisher: IEEE
 
» Studying the Influence of n-Type Strained (111) Silicon on the Piezoresistive Coefficients
Abstract:
This paper investigates the effect of inducing a pre-strain state into the (111) silicon substrate on the piezoresistive coefficients. For this purpose, a ten-element sensing rosette has been fabricated on strained and unstrained silicon substrates and fully calibrated using uniaxial, thermal, and hydrostatic loading. The strained silicon technique was integrated during the microfabrication process using a highly compressive film produced by plasma enhanced chemical vapor deposition silicon nitride. This layer induces a tensile strain at the front side of the substrate where the sensing elements were fabricated. The calibration results show that the tensile strained silicon has smaller longitudinal and transverse piezoresistive coefficients than those on unstrained silicon. On the other hand, the shear piezoresistive and the pressure coefficients were increased by 23% and 30%, respectively.
Autors: Amr A. Balbola;Mohammed O. Kayed;Walied A. Moussa;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 302 - 310
Publisher: IEEE
 
» Studying the loss of life of natural-ester-filled transformer insulation: impact of moisture on the aging rate of paper
Abstract:
Moisture is one of the most harmful agents for transformer solid insulation. The catalyzing effect of moisture on the degradation process of paper and pressboard has been studied by several authors, who developed models which they used to estimate how the aging process would be accelerated in the presence of water [1]–[5]. In [2] and [3] Lelekakis et al. reported the results of an experimental study in which samples with different moisture contents were aged in the presence of mineral oil (MO). In [3] an equation to determine the reduction of service lifetime of insulation subjected to increased temperature and with increased moisture content is proposed.
Autors: Belen Garcia;Tamara Garcia;Victor Primo;Juan Carlos Burgos;Domingo Urquiza;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Jan 2017, volume: 33, issue:1, pages: 15 - 23
Publisher: IEEE
 
» Sub-Band Pre-Distortion for PAPR Reduction in Spectral Efficient 5G Mobile Fronthaul
Abstract:
We propose a pre-distortion scheme in transmitter DSP to reduce the peak-to-average power ratio (PAPR) in multi-intermediate-frequency (IF)-over-fiber mobile fronthaul (MFH). In optical spectral efficient MFH, multiple modulated sub-bands are transmitted with different IFs serving multi-in multi-out and carrier aggregation in 5G. By applying phase pre-distortion on sub-bands in the transmitter DSP, we reduce the PAPR by more than 2.2 dB with 1% complementary cumulative distribution function value in MFH for 5G mobile networks and significantly increase the transmitted signal power and quality without modifying the system linearity and resolution. The proposed scheme generates small latency. It is DSP efficient and compatible with current mobile devices, without additional noise. With 32 sub-bands served, we demonstrated a 2-dB sensitivity improvement experimentally by applying the proposed scheme.
Autors: Feng Lu;Mu Xu;Lin Cheng;Jing Wang;Shuyi Shen;Junwen Zhang;Gee-Kung Chang;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 122 - 125
Publisher: IEEE
 
» Sub-lithographic Patterning via Tilted Ion Implantation for Scaling Beyond the 7-nm Technology Node
Abstract:
Tilted ion implantation (TII) can be used in conjunction with pre-existing masking features on the surface of a substrate to form features with smaller dimensions and smaller pitch. In this paper, the resolution limit of this sub-lithographic patterning approach is examined via experiments as well as Monte Carlo process simulations. TII is shown to be capable of defining features with size below 10 nm, in a self-aligned manner, reproducing with high fidelity the line-edge roughness of the pre-existing masking features. Since it has relatively low associated process cost, TII-enhanced patterning is a promising approach to advance high-volume manufacture of integrated circuits beyond the 7-nm technology node.
Autors: Peng Zheng;Sang Wan Kim;Daniel Connelly;Kimihiko Kato;Fei Ding;Leonard Rubin;Tsu-Jae King Liu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 231 - 236
Publisher: IEEE
 
» Subcell Modeling of Frequency-Dependent Thin Layers in the FDTD Method
Abstract:
A subcell modeling technique for frequency-dependent thin layers in finite-difference time-domain method is introduced. The proposed method is based on the application of the integral form of the Maxwell–Ampere equation and the solution of a set of auxiliary equations to advance the field components. It has the ability to handle one or several frequency-dependent thin layers embedded in a frequency-dependent medium without solving high-order differential equations. To validate our proposed method, we compare the obtained results with analytical solutions and with numerical references in both time domain and frequency domain.
Autors: Kenan Tekbas;Fumie Costen;Jean-Pierre Bérenger;Ryutaro Himeno;Hideo Yokota;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 278 - 286
Publisher: IEEE
 
» Subspace Identification of Distributed Clusters of Homogeneous Systems
Abstract:
This note studies the identification of a network comprised of interconnected clusters of LTI systems. Each cluster consists of homogeneous dynamical systems, and its interconnections with the rest of the network are unmeasurable. A subspace identification method is proposed for identifying a single cluster using only local input and output data. With the topology of the concerned cluster being available, all the LTI systems within the cluster are decoupled by taking a transformation on the state, input and output data. To deal with the unmeasurable interconnections between the concerned cluster and the rest of the network, the Markov parameters of the decoupled LTI systems are identified first by solving a nuclear-norm regularized convex optimization, following the state-space realization of a single LTI system within the cluster by solving another nuclear-norm regularized optimization problem. The effectiveness of the proposed identification method is demonstrated by a simulation example.
Autors: Chengpu Yu;Michel Verhaegen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 463 - 468
Publisher: IEEE
 
» Subthreshold Operation of CAAC-IGZO FPGA by Overdriving of Programmable Routing Switch and Programmable Power Switch
Abstract:
A field-programmable gate array (FPGA) using a crystalline oxide semiconductor of c-axis-aligned crystal indium-gallium–zinc oxide (CAAC-IGZO) has been developed, which is capable of subthreshold operation used for energy harvesting. To achieve subthreshold operation, the CAAC-IGZO FPGA has a structure designed as an extension of a boosting pass gate using a CAAC-IGZO FET and employs overdriving of a programmable routing switch and a programmable power switch for power gating (PG). A CAAC-IGZO FET is used to give an ideal floating gate with excellent charge retention. A chip fabricated using a 0.8- CAAC-IGZO/0.18- CMOS hybrid process achieves subthreshold operation while maintaining the features required for normally off computing proposed in our previous study. Specifically, these features are realized by fine-grained PG for individual programmable logic elements (PLEs), fast configuration switching between contexts, and load/store between a volatile register and a nonvolatile shadow register in the PLEs. The chip operation at a minimum operating voltage of 180 mV with a combinational circuit configuration is demonstrated. With a sequential circuit configuration, the chip operates at a minimum operating voltage of 190 mV with 12.5 kHz, and the minimum power-delay product is 3.40 pJ/operation at 330 mV.
Autors: Munehiro Kozuma;Yuki Okamoto;Takashi Nakagawa;Takeshi Aoki;Yoshiyuki Kurokawa;Takayuki Ikeda;Yoshinori Ieda;Naoto Yamade;Hidekazu Miyairi;Makoto Ikeda;Masahiro Fujita;Shunpei Yamazaki;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 125 - 138
Publisher: IEEE
 
» Success Probability of the Babai Estimators for Box-Constrained Integer Linear Models
Abstract:
In many applications including communications, one may encounter a linear model where the parameter vector is an integer vector in a box. To estimate , a typical method is to solve a box-constrained integer least squares problem. However, due to its high complexity, the box-constrained Babai integer point is commonly used as a suboptimal solution. In this paper, we first derive formulas for the success probability of and the success probability of the ordinary Babai integer point when is uniformly distributed over the constraint box. Some properties of and and the relationship between them are studied. Then, we investigate the effects of some column permutation strategies on . In addition to V-BLAST and SQRD, we also consider the permutation strategy involved in the LLL lattice reduction, to be referred to as LLL-P. On the one hand, we - how that when the noise is relatively small, LLL-P always increases and argue why both V-BLAST and SQRD often increase ; and on the other hand, we show that when the noise is relatively large, LLL-P always decreases and argue why both V-BLAST and SQRD often decrease . We also derive a column permutation invariant bound on , which is an upper bound and a lower bound under these two opposite conditions, respectively. Numerical results demonstrate our findings. Finally, we consider a conjecture concerning proposed by Ma et al. We first construct an example to show that the conjecture does not hold in general, and then show that it does hold under some conditions.
Autors: Jinming Wen;Xiao-Wen Chang;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 631 - 648
Publisher: IEEE
 
» Superpixel-Based Active Learning and Online Feature Importance Learning for Hyperspectral Image Analysis
Abstract:
The rapid development of multichannel optical imaging sensors has led to increased utilization of hyperspectral data for remote sensing. For classification of hyperspectral data, an informative training set is necessary for ensuring robust performance. However, in remote sensing and other image analysis applications, labeled samples are often difficult, expensive, and time-consuming to obtain. This makes active learning (AL) an important part of an image analysis framework—AL aims to efficiently build a representative and efficient library of training samples that are most informative for the underlying classification task. This paper proposes an AL framework that leverages from superpixels. A spatial-spectral AL method is proposed that integrates spatial and spectral features extracted from superpixels in an AL framework. The experiments with an urban land cover classification and a wetland vegetation mapping task show that the proposed method has faster convergence and superior performance as compared to state of the art approaches. Additionally, our proposed framework has a key additional benefit in that it is able to identify and quantify feature importance—the resulting insights can be highly valuable to various remote sensing image analysis tasks.
Autors: Jielian Guo;Xiong Zhou;Jun Li;Antonio Plaza;Saurabh Prasad;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 347 - 359
Publisher: IEEE
 
» Superposition Coding for Downlink Underwater Acoustic OFDM
Abstract:
Superposition coding (SC) is a nonorthogonal scheme for downlink communications, in which all users are allowed to use the full degrees of freedom of the channel and successive interference cancellation (SIC) is adopted for user decoding. Combining SC with orthogonal frequency-division multiplexing (OFDM) modulation, the optimal resource allocation depends on the perfect channel state information (CSI) of all users at the transmitter, which is hard to obtain for underwater acoustic (UWA) channels. In this paper, we propose a practical OFDM-modulated SC scheme for downlink UWA communications, where the transmitter splits the power between two users based on statistical CSI. The expressions to characterize the boundary of the ergodic rate region achievable by the proposed scheme over long codewords are presented first, followed by the analysis of outage probability when coding is applied within one OFDM block. Then we examine the performance of SC in an OFDM-modulated system with practical coding and modulation pairs. Simulation results show that the OFDM-modulated SC scheme outperforms the orthogonal frequency-division multiple access (OFDMA) in performance of both block error rate (BLER) and spectral efficiencies under different data rate pairs. Recorded data from both medium-range and short-range sea tests verify that channel statistics are stable over a long period of time and can be used to assist resource allocation for the proposed scheme. Compared with OFDMA, considerable increase of spectral efficiencies has been found for SC based on experimental data when both users with disparate channels have nonzero data rates.
Autors: Lu Ma;Shengli Zhou;Gang Qiao;Songzuo Liu;Feng Zhou;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 175 - 187
Publisher: IEEE
 
» Supervised Feature Extraction of Hyperspectral Images Using Partitioned Maximum Margin Criterion
Abstract:
Dimensionality reduction is an important task where the aim is to reduce the number of features and make the system less time consuming for classification. Here, the drawbacks of Fisher’s linear-discriminant-analysis-based feature extraction (FE) methods are addressed and a proposal is made to overcome it as well as to reduce the Hughes phenomenon and computational complexity of the system. The proposed FE technique initially partitions the complete set of features into several highly correlated subgroups. Then a linear transformation is performed using a maximal margin criterion over each subgroup. The proposed method is supervised in nature, because prior information about the class label of data is required to calculate the maximum margin criterion based on interclass and intraclass scatter matrices. Experiments are conducted with the PaviaU and Indian pine data sets, and the results are compared with five state-of-the-art techniques, both qualitatively and quantitatively, to demonstrate the effectiveness of the proposed method.
Autors: Aloke Datta;Susmita Ghosh;Ashish Ghosh;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 82 - 86
Publisher: IEEE
 
» Support Vector Machine Informed Explicit Nonlinear Model Predictive Control Using Low-Discrepancy Sequences
Abstract:
In this paper, an explicit nonlinear model predictive controller (ENMPC) for the stabilization of nonlinear systems is investigated. The proposed ENMPC is constructed using tensored polynomial basis functions and samples drawn from low-discrepancy sequences. Solutions of a finite-horizon optimal control problem at the sampled nodes are used 1) to learn an inner and outer approximation of the feasible region of the ENMPC using support vector machines, and 2) to construct the ENMPC control surface on the computed feasible region using regression or sparse-grid interpolation, depending on the shape of the feasible region. The attractiveness of the proposed control scheme lies in its tractability to higher-dimensional systems with feasibility and stability guarantees, significantly small online computation times, and ease of implementation.
Autors: Ankush Chakrabarty;Vu Dinh;Martin J. Corless;Ann E. Rundell;Stanisław H. Żak;Gregery T. Buzzard;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 135 - 148
Publisher: IEEE
 
» Suppressed Hysteretic Field Emission From Polymer Encapsulated Silver Nanowires
Abstract:
Suppression of the hysteretic electron emission in one-dimensional nanomaterial-based electron sources remains a critical barrier preventing their wide scale adoption in various vacuum electronics applications. Here, we report on the suppressed hysteretic performance, and its photo-dependence from conformal poly-vinylpyrrolidone encapsulated percolative Ag nanowire-based electron sources.
Autors: Matthew T. Cole;Sahin Coskun;Richard J. Parmee;Pritesh Hiralal;Cinzia Cepek;Alexander W. Robertson;Chi Li;Qing Dai;Jamie H. Warner;William I. Milne;Husnu E. Unalan;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 11 - 15
Publisher: IEEE
 
» Suppression of Persistent Photoconductivity in AlGaN/GaN Ultraviolet Photodetectors Using In Situ Heating
Abstract:
Photodetectors based on the AlGaN/GaN heterostructure suffer from persistent photoconductivity (PPC) in which recovery from the optical stimulus can take days. This behavior is unsuitable for many applications where reliable and consistent optical response is required. This letter presents a method for suppressing PPC in AlGaN/GaN photodetectors by employing device suspension and in situ heating. The highly conductive two-dimensional electron gas (2DEG) at the interface of AlGaN and GaN serves as both a sensor and a heater (via Joule heating). Microfabricated AlGaN/GaN-on-Si ultraviolet (UV) photodetectors (suspended and unsuspended) were exposed to UV (365 nm) for 60 s and the transient responses were measured under various in situ heating conditions. The measured transient response showed a decay time of ~39 h when the photodetector was not heated and 24 s for a suspended photodetector with in situ 2DEG heating (270°C with a power of 75 mW). This remarkable suppression of the PPC in AlGaN/GaN UV photodetectors can be attributed to the novel device architecture and in situ heating capability, which enables acceleration of the carrier capture rate during operation.
Autors: Minmin Hou;Hongyun So;Ateeq J. Suria;Ananth Saran Yalamarthy;Debbie G. Senesky;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 56 - 59
Publisher: IEEE
 
» Symbol-Based Belief Propagation Decoder for Multilevel Polar Coded Modulation
Abstract:
In this letter, symbol-based belief propagation decoder is proposed for multilevel polar coded modulation (MLPCM) scheme. Unlike the traditional multi-stage detection (MSD) strategy by decoding polar codes level by level after demapping, we directly calculate the probabilities of symbols and do demapping after the symbol decoding process so as to decrease the decoding delay and improve the performance of MLPCM. The lower bound of frame error rate for MLPCM is also estimated using the union bound technique. Numerical results show that the performance of proposed decoder well matches the estimated bound for pulse amplitude modulation (PAM) modulation and outperforms the MSD strategy about 0.5−1 dB with lower decoding delay, only at the cost of some additional computational complexity, which indicates its effectiveness.
Autors: Qingshuang Zhang;Aijun Liu;Xiaofei Pan;Yingxian Zhang;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 24 - 27
Publisher: IEEE
 
» Symmetric Operation in an Extended Back Gate JLFET for Scaling to the 5-nm Regime Considering Quantum Confinement Effects
Abstract:
In this paper, we propose a double gate junctionless FET (DGJLFET) with an extended back gate (EBG) architecture for significantly improved performance in the sub-10-nm regime. Even for a channel length of 5 nm, we show using calibrated 2-D simulations that the EBG DGJLFET, when compared with the DGJLFET, exhibits: 1) an improved subthreshold swing; 2) a significantly low off-state leakage current; and 3) a considerably high ratio of . Furthermore, we demonstrate, for the first time, that the quantum confinement-induced bandgap widening diminishes the parasitic bipolar junction transistor (BJT) action and, therefore, facilitates the scaling of the conventional DGJLFETs to the sub-5-nm channel regime where the quantization effects are significant. Moreover, we also show, for the first time, that the DG junctionless accumulation mode FET suffers from an enhanced parasitic BJT action and, therefore, a significantly high off-state leakage current compared with the DGJLFET. In addition, we demonstrate that the loss of gate control for negative gate voltages in the DGJLFETs with larger silicon film doping ( cm) is due to a shielding effect initiated by the band-to-band tunneling.
Autors: Shubham Sahay;Mamidala Jagadesh Kumar;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 21 - 27
Publisher: IEEE
 
» Synchronization of Goodwin's Oscillators under Boundedness and Nonnegativeness Constraints for Solutions
Abstract:
In the recent paper by Hamadeh et al. (2012) an elegant analytic criterion for incremental output feedback passivity (iOFP) of cyclic feedback systems (CFS) has been reported, assuming that the constituent subsystems are incrementally output strictly passive (iOSP). This criterion was used to prove that a network of identical CFS can be synchronized under sufficiently strong linear diffusive coupling. A very important class of CFS consists of biological oscillators, named after Brian Goodwin and describing self-regulated chains of enzymatic reactions, where the product of each reaction catalyzes the next reaction, while the last product inhibits the first reaction in the chain. Goodwin's oscillators are used, in particular, to model the dynamics of genetic circadian pacemakers, hormonal cycles and some metabolic pathways. In this technical note we point out that for Goodwin's oscillators, where the individual reactions have nonlinear (e.g., Mikhaelis-Menten) kinetics, the synchronization criterion, obtained by Hamadeh et al., cannot be directly applied. This criterion relies on the implicit assumption of the solution boundedness, dictated also by the chemical feasibility (the state variables stand for the concentrations of chemicals). Furthermore, to test the synchronization condition one needs to know an explicit bound for a solution, which generally cannot be guaranteed under linear coupling. At the same time, we show that these restrictions can be avoided for a nonlinear synchronization protocol, where the control inputs are “saturated” by a special nonlinear function (belonging to a wide class), which guarantees nonnegativity of the solutions and allows to get explicit ultimate bounds for them. We prove that oscillators synchronize under such a protocol, provided - hat the couplings are sufficiently strong.
Autors: Anton V. Proskurnikov;Ming Cao;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 372 - 378
Publisher: IEEE
 
» Tactile Diagrams for the Visually Impaired
Abstract:
In this information-driven era, the use of pictorial forms of communication has become widely popular, making the world increasingly inaccessible to visually impaired and blind individuals. Accessing print media has also been a challenge for this population. Braille, a standard writing system for perception through touch, and audio translations of written text have made books accessible to the visually impaired. However, both these formats fail to make pictures and graphics accessible to the blind.
Autors: Richa Gupta;M. Balakrishnan;P.V.M. Rao;
Appeared in: IEEE Potentials
Publication date: Jan 2017, volume: 36, issue:1, pages: 14 - 18
Publisher: IEEE
 
» Tangential Interpolatory Projection for Model Reduction of Linear Quantum Stochastic Systems
Abstract:
This paper presents a model reduction method for the class of linear quantum stochastic systems often encountered in quantum optics and related fields. The approach is proposed on the basis of an interpolatory projection ensuring that specific input-output responses of the original and the reduced-order systems are matched at multiple selected points (or frequencies). Importantly, the physical realizability property of the original quantum system imposed by the laws of quantum mechanics is preserved under our tangential interpolatory projection. Error bounds are established for the proposed model reduction method and an avenue to select interpolation points is proposed. A passivity preserving model reduction method is also presented. Examples of both active and passive systems are provided to illustrate the merits of our proposed approach.
Autors: Onvaree Techakesari;Hendra I. Nurdin;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 5 - 17
Publisher: IEEE
 
» Task Space Control of an Autonomous Underwater Vehicle Manipulator System by Robust Single-Input Fuzzy Logic Control Scheme
Abstract:
In this paper, a robust single-input fuzzy logic control Robust Single Input Fuzzy Logic Controller (RSIFLC) scheme is proposed and applied for task-space trajectory control of an autonomous underwater vehicle manipulator system (AUVMS) employed for underwater manipulation tasks. The effectiveness of the proposed control scheme is numerically demonstrated on a planar underwater vehicle manipulator system [consisting of an underwater vehicle and a two link rotary (2R) serial planar manipulator]. The actuator and sensor dynamics of the system are also incorporated in the dynamical model of an AUVMS. The proposed control law consists of a feedforward term to exaggerate the control activity with immoderation from the known desired acceleration vector and an estimated perturbed term to compensate for the unknown effects namely external disturbances and unmodeled dynamics as a first part and a single-input fuzzy logic control as a feedback portion to enhance the overall closed-loop stability of the system as a second part. The primary objective of the proposed control scheme is to track the given end-effector task space trajectory despite of external disturbances, system uncertainties, and internal noises associated with the AUVMS. To show the efficacy of the proposed control scheme, comparison is made with conventional fuzzy logic control (CFLC), sliding mode control (SMC), and proportional–integral–derivative (PID) controllers. Simulation results confirmed that with the proposed control scheme, the AUVMS can successfully track the given desired spatial trajectory and gives better and robust control performance.
Autors: Pandurang S. Londhe;M. Santhakumar;Balasaheb M. Patre;Laxman M. Waghmare;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 13 - 28
Publisher: IEEE
 
» TCP Download Performance in Dense WiFi Scenarios: Analysis and Solution
Abstract:
How does a dense WiFi network perform, specifically for the common case of TCP download? While the empirical answer to this question is ‘poor’, analysis and experimentation in prior work has indicated that TCP clocks itself quite well, avoiding contention-driven WiFi overload in dense settings. This paper focuses on measurements from a real-life use of WiFi in a dense scenario: a classroom where several students use the network to download quizzes and instruction material. We find that the TCP download performance is poor, contrary to that suggested by prior work. Through careful analysis, we explain the complex interaction of various phenomena which leads to this poor performance. Specifically, we observe that a small amount of upload traffic generated when downloading data upsets the TCP clocking, and increases contention on the channel. Further, contention losses lead to a vicious cycle of poor interaction with autorate adaptation and TCP's timeout mechanism. To reduce channel contention and improve performance, we propose a modification to the AP scheduling policy to improve the performance of large TCP downloads. Our solution, WiFiRR, picks only a subset of clients to be served by the AP during any instant, and varies this set of “active” clients periodically in a round-robin fashion over all clients to ensure that no client starves. We have done extensive evaluation of WiFiRR in simulation and in real settings. By reducing the number of contending nodes at any point of time, WiFiRR improves the download time of large TCP flows upto of our classroom scenario. We also compare WiFiRR with state-of-the-art prior work WiFox, WiFiRR improves download time by over WiFox.
Autors: Mukulika Maity;Bhaskaran Raman;Mythili Vutukuru;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 213 - 227
Publisher: IEEE
 
» Teaching the Principles of Massive MIMO: Exploring reciprocity-based multiuser MIMO beamforming using acoustic waves
Abstract:
Massive multiple-input, multiple-output (MIMO) is currently the most compelling wireless physical layer technology and a key component of fifth-generation (5G) systems. The understanding of its core principles has emerged during the last five years, and material is becoming available that is rigorously refined to focus on timeless fundamentals [1], facilitating the instruction of the topic to both master- and doctoral-level students [2]. Meaningful laboratory work that exposes the operational principles of massive MIMO is more difficult to accomplish. At Linköping University, Sweden, this was achieved through a project course, based on the conceive-design-implement-operate (CDIO) concept [3], and through the creation of a specially designed experimental setup using acoustic signals.
Autors: Erik G. Larsson;Danyo Danev;Mikael Olofsson;Simon Sorman;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 40 - 47
Publisher: IEEE
 
» Temperature Interference Reduction for Pressure Sensor Made of Conductive Polymer Composite
Abstract:
To lower the temperature interference on the piezoresistive sensor made of conductive polymer composite, a differential structure composed of “positive piezoresistive and positive thermoresistive unit (PPPTU)” and “negative piezoresistive and positive thermoresistive unit (NPPTU)” is designed. The mass ratio of carbon black to silicone rubber in the composite in PPPTU is 0.06, which results in the increase of the electrical resistance of the composite with the increase of the compressive pressure/temperature. The mass ratio in NPPTU is 0.12, which results in the decrease/increase of the resistance of the composite with the increase of the compressive pressure/temperature. PPPTU and NPPTU are placed on the neighboring arms of an electrical bridge to construct a differential structure. The experimental results verify the feasibility of using the differential structure based on PPPTU and NPPTU to reduce the temperature interference.
Autors: Luheng Wang;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 123 - 125
Publisher: IEEE
 
» Temperature-Insensitive Optical Fiber Curvature Sensor Based on SMF-MMF-TCSMF-MMF-SMF Structure
Abstract:
A new optical fiber curvature sensor dominated by three-core single mode fiber (TCSMF) is proposed and demonstrated. The sensing structure is formed by cascading multimode fiber (MMF), TCSMF and MMF together, namely, the SMF-MMF-TCSMF-MMF-SMF structure. Three core modes in the TCSMF interfere with each other and then form the interference spectrum. The interference phase difference is changed due to the elastic-optic effect as bending deformation inflicted on the fiber. Thus the spectrum can be shifted accordingly. The two short segments of MMF can significantly improve the coupling efficiency between the fundamental mode and three core modes, and get high fringe visibility. Experiments show that the highest curvature sensitivity of −28.29 nm/ is achieved in the range of 2.79–3.24 . Moreover, this sensor possesses the temperature-insensitive characteristic on account of the similar thermo-optic coefficient among three cores.
Autors: Yong Zhao;Lu Cai;Xue-Gang Li;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 141 - 147
Publisher: IEEE
 
» Temporal Task Scheduling With Constrained Service Delay for Profit Maximization in Hybrid Clouds
Abstract:
As cloud computing is becoming growingly popular, consumers’ tasks around the world arrive in cloud data centers. A private cloud provider aims to achieve profit maximization by intelligently scheduling tasks while guaranteeing the service delay bound of delay-tolerant tasks. However, the aperiodicity of arrival tasks brings a challenging problem of how to dynamically schedule all arrival tasks given the fact that the capacity of a private cloud provider is limited. Previous works usually provide an admission control to intelligently refuse some of arrival tasks. Nevertheless, this will decrease the throughput of a private cloud, and cause revenue loss. This paper studies the problem of how to maximize the profit of a private cloud in hybrid clouds while guaranteeing the service delay bound of delay-tolerant tasks. We propose a profit maximization algorithm (PMA) to discover the temporal variation of prices in hybrid clouds. The temporal task scheduling provided by PMA can dynamically schedule all arrival tasks to execute in private and public clouds. The sub problem in each iteration of PMA is solved by the proposed hybrid heuristic optimization algorithm, simulated annealing particle swarm optimization (SAPSO). Besides, SAPSO is compared with existing baseline algorithms. Extensive simulation experiments demonstrate that the proposed method can greatly increase the throughput and the profit of a private cloud while guaranteeing the service delay bound.
Autors: Haitao Yuan;Jing Bi;Wei Tan;Bo Hu Li;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 337 - 348
Publisher: IEEE
 
» Temporally Constrained Group Sparse Learning for Longitudinal Data Analysis in Alzheimer's Disease
Abstract:
Sparse learning has been widely investigated for analysis of brain images to assist the diagnosis of Alzheimer's disease and its prodromal stage, i.e., mild cognitive impairment. However, most existing sparse learning-based studies only adopt cross-sectional analysis methods, where the sparse model is learned using data from a single time-point. Actually, multiple time-points of data are often available in brain imaging applications, which can be used in some longitudinal analysis methods to better uncover the disease progression patterns. Accordingly, in this paper, we propose a novel temporallyconstrained group sparse learning method aiming for longitudinal analysis with multiple time-points of data. Specifically, we learn a sparse linear regression model by using the imaging data from multiple time-points, where a group regularization term is first employed to group the weights for the same brain region across different time-points together. Furthermore, to reflect the smooth changes between data derived from adjacent time-points, we incorporate two smoothness regularization terms into the objective function, i.e., one fused smoothness term thatrequires that the differences between two successive weight vectors from adjacent time-points should be small, and another output smoothness term thatrequires the differences between outputs of two successive models from adjacent time-points should also be small. We develop an efficient optimization algorithm to solve the proposed objective function. Experimental results on ADNI database demonstrate that, compared with conventional sparse learning-based methods, our proposed method can achieve improved regression performance and also help in discovering disease-related biomarkers.
Autors: Biao Jie;Mingxia Liu;Jun Liu;Daoqiang Zhang;Dinggang Shen;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 238 - 249
Publisher: IEEE
 
» Temporarily Fine-Grained Sleep Technique for Near- and Subthreshold Parallel Architectures
Abstract:
This paper presents a design approach for improving energy-efficiency and throughput of parallel architectures in near- and subthreshold voltage circuits. The focus is to suppress leakage energy dissipation of the idle portions of circuits during active modes, which can allow us to wholly transform the throughput improvement from parallel architectures into energy savings via deep voltage scaling. We begin by investigating the efficacy of parallel and pipeline architectures in the near- and subthreshold circuits. The investigation reveals that active energy dissipation largely undermines the ability of deep voltage scaling to transform excessive throughput into energy savings. Techniques, such as power-gating switches (PGSs), can mitigate active-leakage power dissipation; however, the overhead for entering and exiting sleep modes can offset the energy savings provided by sleep mode, particularly if sleep time is fine grained for suppressing active leakage. Therefore, in this paper, we propose a PGS design technique, inspired by the so-called zigzag supercutoff CMOS, in order to optimize the overheads of mode transitions of PGS in near- and subthreshold circuits. The proposed technique enables to have circuits in sleep mode for as short as a single clock cycle with a negligible amount of energy and delay overheads. We apply our proposed design to parallel multiplier-based test circuits operating at near- and subthreshold voltages. Simulations show a significant improvement in energy-efficiency over baselines at the same throughput.
Autors: Joao Pedro Cerqueira;Mingoo Seok;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 189 - 197
Publisher: IEEE
 
» Tensor-Based Dictionary Learning for Spectral CT Reconstruction
Abstract:
Spectral computed tomography (CT) produces an energy-discriminative attenuation map of an object, extending a conventional image volume with a spectral dimension. In spectral CT, an image can be sparsely represented in each of multiple energy channels, and are highly correlated among energy channels. According to this characteristics, we propose a tensor-based dictionary learning method for spectral CT reconstruction. In our method, tensor patches are extracted from an image tensor, which is reconstructed using the filtered backprojection (FBP), to form a training dataset. With the Candecomp/Parafac decomposition, a tensor-based dictionary is trained, in which each atom is a rank-one tensor. Then, the trained dictionary is used to sparsely represent image tensor patches during an iterative reconstruction process, and the alternating minimization scheme is adapted for optimization. The effectiveness of our proposed method is validated with both numerically simulated and real preclinical mouse datasets. The results demonstrate that the proposed tensor-based method generally produces superior image quality, and leads to more accurate material decomposition than the currently popular popular methods.
Autors: Yanbo Zhang;Xuanqin Mou;Ge Wang;Hengyong Yu;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 142 - 154
Publisher: IEEE
 
» Terahertz Heterodyne Communication Using GaAs Field-Effect Transistor Receiver
Abstract:
We report the first successful terahertz heterodyne communication using a field-effect transistor for detection. The communication is a real-time transmission of an uncompressed high-definition TV signal at a data rate of 1.5 Gbps with a 307-GHz carrier frequency. The emitter is a frequency-multiplied amplifier chain whose last stage is a second harmonic mixer that multiplies the carrier signal by the data. The receiver only consists of a GaAs high-electron-mobility transistor that acts as a quadratic receiver, and two 20-dB-gain amplifiers, no limiting amplifier or forward error correction were used. A direct communication would be impossible with such a combination of modulation scheme at emission and quadratic detection at reception, while it is possible in a heterodyne configuration. In addition, for the same source power, the heterodyne scheme allows to increase the communication bandwidth from 80 MHz to more than 2 GHz for a local oscillator power of −8 dBm.
Autors: Stéphane Blin;Philippe Nouvel;Annick Pénarier;Jeffrey Hesler;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 20 - 23
Publisher: IEEE
 
» Terahertz Metasurfaces for Absorber or Reflectarray Applications
Abstract:
A terahertz (THz) metasurface, with the unit cells consisting of double metal loops and a metallic back film on both sides of the dielectric layer, is investigated to find the connection between reflectivity and pattern geometry. An equivalent circuit of the unit cell is also given to ease the analysis and predication of the reflection coefficient and also to provide a guideline for tuning the impedance of the metasurface. An absorber and a reflectarray, as two typical applications of the metasurface that need low and high reflection efficiency, respectively, are demonstrated at ~0.9 THz by varying dimensional parameters of the metal loops. The absorber can reach 0.102-THz bandwidth for reflectivity below −10 dB under normal incidence and also shows independence on polarization and incident angle, while the reflectarray antenna gain can reach 22 dBi at 0.875 THz. Finally, an absorber and a reflective surface prototype were fabricated and measured. Factors affecting the reflectivity and resonances introduced in the fabrication process are identified, which provides an important reference to design other kinds of THz devices.
Autors: Long Chen;Shi-Wei Qu;Bao-Jie Chen;Xue Bai;Kung-Bo Ng;Chi Hou Chan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 234 - 241
Publisher: IEEE
 
» Test Stimulus Compression Based on Broadcast Scan With One Single Input
Abstract:
In this paper, a novel test compression technique is proposed that can achieve very high test compression ratio with low area overhead and only one single test input. An inverter and a series of D flip-flops together with a configurable switch logic are inserted between the single input and the scan chains so as to convert the input patterns to the test data required by each scan chain. All scan chains are divided into some scan groups such that scan chains in the same group can share the same test data and the switch logic only needs to connect each group to an appropriate data provider. Hence the total area overhead is quite small. A novel algorithm is developed to determine the required test configurations and corresponding test patterns for 100% testable fault coverage. Experimental results show that on average this method can achieve data reduction factors of , , and with 3.77%, 0.95%, and 0.03% area overhead for ISCAS’89, IWLS’05 OpenCores, and IWLS’05 Gaisler Research benchmark circuits, respectively. These results indicate that the reduction factor increases with the sizes of circuits; it even reaches for a circuit containing 2.07 million gates with very small area overhead. As all test and control data can be provided by a single input, great reduction on test channel requirement is also achieved.
Autors: Jhen-Zong Chen;Kuen-Jong Lee;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 184 - 197
Publisher: IEEE
 
» Textile Resonators With Thin Copper Wire for Wearable MR-WPT System
Abstract:
This letter presents the comparison of performance of planar textile resonators (PTRs) with various forms of conductive patterns. The conductive materials of the conductive pattern included copper sheet and copper wires of three different thicknesses. The PTRs with thin copper wires were found to be flexible and stable for wearable applications. To verify the performance of PTRs in MR-WPT, a symmetrical four-coil system was measured. This study considered the normal and standard condition of PTRs without any forms of modification in physical. The results showed that thin copper wires, especially of 1.0 mm thickness, had the highest transfer efficiency of 75.66% because the thickness of copper sheet is not sufficient for skin depth and the current was over ampacity of copper sheet.
Autors: Seok Hyon Kang;Chang Won Jung;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 91 - 93
Publisher: IEEE
 
» The $R_{mathrm{scriptscriptstyle ON},mathrm {min}}$ of Balanced Symmetric Vertical Super Junction Based on R-Well Model
Abstract:
The global optimization of the balanced symmetric vertical superjunction (VSJ) device is proposed based on the R-well model for the first time to realize the unique minimum specific on-resistance . The R-well model, which is originated from our previous VSJ mode theory, shows the relationship between and the doping concentration N under the given pillar width W and breakdown voltage . The global optimization is realized to obtain the design formulas of N and the pillar length . The calculated results are in good agreement with the simulations. It is demonstrated from the comparisons with the simulations and the existing experiments that the optimization in this paper realizes the unique with a relationship of . The R-well model is also universal for other optimizations.
Autors: Wentong Zhang;Bo Zhang;Ming Qiao;Zehong Li;Xiaorong Luo;Zhaoji Li;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 224 - 230
Publisher: IEEE
 
» The 36 V Bipolar: $beta times V_{a} times text {fT} times text {BV} times text {JfT} times$ Linearity Tradeoff
Abstract:
This paper reports on the optimization of a 36 V complimentary bipolar design by using a new depletion mode field-effect architecture for the collector of the bipolar that greatly expands the boundary of the familiar tradeoffs. This achieves an n-p-n with a measured at 1 V at 18 , a JfT at 1 V = , and fT at 1 V BV GHz , with a p-n-p having a at 1 V at 18 , a JfT at 1 V = , and fT at 1 V BV GHz . While these performance enhancements appear to offer a lot with little expense, they do serve to reveal an additional tradeoff between fT BV JfT and Linearity. This is where the curvature of the forward output characteristic curves quantified by the extrapolated Early voltage significantly changes over the voltage range –10 . Through the use of measured silicon results with calibrated TCAD simulations, the physics behind this depletion mode collector design is explained, and using this understanding, it ultimately shows how it is possible to limit the range of the associated nonlinear performance for low collector biases. Then, keeping linearity as a key performance target together with the field-effect architecture, the 36 V bipolar is rebalanced to achieve an n-p-n with a at 1 V at 18 V fT at 1 V JfT at 1 V BV Linearity V $times2.6$
Autors: Edward J. Coyne;Shay Whiston;Breandán Pól Ó hAnnaidh;Donal P. McAuliffe;Bill Lane;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 8 - 14
Publisher: IEEE
 
» The Assessment of Ground-Based Weather Radar Data by Comparison With TRMM PR
Abstract:
The Precipitation Radar (PR) on the Tropical Rainfall MeasuringMission satellite has already provided reliable observations for more than 15 years. There is a potential possibility to assess long-term data of ground-based radar (GR) in the China new generation weather radar network through comparison between PR and GR. In this letter, stratiform precipitation above and below bright bands is used to implement reflectivity comparison for PR and the ground-based weather radar in Nanjing from 2003 to 2014. The results show that the accuracy of GR reflectivity is well correlated with the distance from GR, and there are several unusual years in which GR did not work properly. The comparison also indicates that bias of reflectivity between PR and GR is negative above bright bands but positive below bright bands, and the bias has high correlation with GR reflectivity. The proposed scheme provides a practical method for a sanity check of GR data.
Autors: Nan Li;Zhenhui Wang;Fen Xu;Zhigang Chu;Yiqing Zhu;Jing Han;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 72 - 76
Publisher: IEEE
 
» The Beauty of Symmetry: Common-Mode Rejection Filters for High-Speed Interconnects and Band Microwave Circuits
Abstract:
Common-mode rejection filters operating at microwave frequencies have been the subject of intensive research activity over the last decade. These filters are of interest for the suppression of common-mode noise in high-speed digital circuits, where differential signals are widely employed due to the high immunity to noise, electromagnetic (EM) interference, and crosstalk of differential-mode interconnects. These filters can also be used to improve common-mode rejection in microwave filters and circuits dealing with differential signals. Ideally, common-mode stopband filters should be transparent for the differential mode from dc up to very high frequencies (all pass), preserve the signal integrity for such mode, and exhibit the widest and deepest possible rejection band for the common mode in the region of interest. Moreover, these characteristics should be achieved by means of structures with the smallest possible size.
Autors: Ferran Martin;Jordi Naqui;Armando Fernandez-Prieto;Paris Velez;Jordi Bonache;Jesus Martel;Francisco Medina;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 42 - 55
Publisher: IEEE
 
» The Capacity of a Class of Channels With Coded Side Information at the Decoder
Abstract:
We study the Ahslwede–Han problem of a point-to-point communication with partial state information available at the destination. For a class of channels, by establishing a tight converse, we show that the Wyner–Ziv compression of the channel state treating the destination’s channel output as side information is optimal. This result is more general than the modulo-sum channel studied by Aleksic et al. and the symmetric binary erasure channel with two states studied by Tandon and Ulukus. Thus, for this more general class of channels, we prove the Ahlswede–Han conjecture.
Autors: Nan Liu;Wei Kang;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 72 - 80
Publisher: IEEE
 
» The Car as an Ambient Sensing Platform
Abstract:
In recent years, cars have evolved from purely mechanical to veritable cyberphysical systems that generate large amounts of real-time data. These data are instrumental to the proper working of the vehicle itself, but make them amenable to a multitude of other uses. For instance, GPS information has recently been used for a large number of mobility studies in the academic community [1], [5], as well as to feed traffic apps such as Google Traffic and Waze. This use of vehicle data is already having a profound impact in science, industry, economy, and society at large. Now, imagine that instead of accessing one single source of vehicle-generated data (GPS), one can access the entire wealth of data exchanged on the controller area network (CAN) bus in near real timeamounting to over 4000 signals sampled at high frequency, corresponding to a few gigabytes of data per hour. What would be the implications, opportunities, and challenges sparked by this transition?
Autors: Emanuele Massaro;Chaewon Ahn;Carlo Ratti;Paolo Santi;Rainer Stahlmann;Andreas Lamprecht;Martin Roehder;Markus Huber;
Appeared in: Proceedings of the IEEE
Publication date: Jan 2017, volume: 105, issue:1, pages: 3 - 7
Publisher: IEEE
 
» The Charge Plasma n-p-n Impact Ionization MOS on FDSOI Technology: Proposal and Analysis
Abstract:
In this paper, we propose the charge plasma n-p-n impact ionization MOS (I-MOS) on a lightly doped p-type silicon film using the charge plasma concept. The performance of the proposed device is exhaustively investigated using 2-D simulations. The proposed device does not have metallurgical junctions and needs no chemical doping for creating the source and drain regions. Therefore, the proposed device combines the benefits of the bipolar I-MOS (low avalanche breakdown voltage and immunity toward the hot carrier injection) and a junctionless FET (low thermal budget process). The proposed charge plasma n-p-n I-MOS exhibits excellent electrical characteristics, such as a low avalanche breakdown voltage of 2.123 V, a steep subthreshold swing of 4.53 mV/decade, and an ratio of , as compared with the conventional bipolar I-MOS.
Autors: Avinash Lahgere;Mamidala Jagadesh Kumar;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 3 - 7
Publisher: IEEE
 
» The Degrees of Freedom of the $K$ -User MIMO Cyclic $Z$ -Interference Channel Under Perfect and Delayed CSIT Assumptions
Abstract:
The degrees of freedom (DoF) region for three users and the sum and symmetric DoF for users are obtained for the multiple-input multiple-output cyclic -interference channel with transmit antennas and receive antennas at each user pair under the separate assumptions of perfect and delayed channel state information at the transmitters (CSIT). New communication schemes based on interference alignment are developed and are shown to be DoF-optimal for all choices of the number of antennas. The maximum sum-DoF scales linearly with the number of users for both perfect and delayed CSIT.
Autors: Kaniska Mohanty;Mahesh K. Varanasi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 17 - 25
Publisher: IEEE
 
» The Design and Development of Assistive Technology
Abstract:
Over the last ten years, the term user-centered design (UCD) has become an essential component of any research proposal that seeks to develop enabling technology for people living with challenging health conditions (assistive technology). While this should be viewed as a very positive development, it is uncertain whether the engineering community fully understands what the term actually means. Is this activity a central component of the work, or just lip service? What do we make of references to participatory design (PD)-is this the same thing? Designability (formerly the Bath Institute of Medical Engineering) has more than 40 years of experience working in this field. In this article, I will review the meanings of these terms, consider some of the challenges of working with people living with disabilities, and detail our experiences of developing successful new designs.
Autors: Nigel Harris;
Appeared in: IEEE Potentials
Publication date: Jan 2017, volume: 36, issue:1, pages: 24 - 28
Publisher: IEEE
 
» The Designated Convergence Rate Problem of Consensus or Flocking of Double-Integrator Agents With General Non-Equal Velocity and Position Couplings
Abstract:
This technical note considers consensus or flocking of coupled multiple double-integrator agents, in which the velocity coupling and position coupling (VCPC) between agents, respectively, are generally non-equal, differing from the equal VCPC setting in the vast literature. This technical note addresses the problem in two aspects: the convergence condition, and particularly the designated convergence rate (or designated convergence margin) condition that was rarely investigated for either flocking, formation, or consensus. Correspondingly, this technical note has two contributions: 1) some necessary and sufficient convergence conditions for flocking or consensus are established, which extend the existing results in the field; and particularly 2) some necessary and sufficient conditions are derived, to guarantee the designated convergence rate of consensus or flocking, which are more valuable for systems design than just convergence analysis performed by most other works on multi-agent systems.
Autors: Wei Li;Guanrong Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 412 - 418
Publisher: IEEE
 
» The Development and Maintenance of Process Procedures
Abstract:
Autors: Raymond E. Floyd;
Appeared in: IEEE Potentials
Publication date: Jan 2017, volume: 36, issue:1, pages: 6 - 9
Publisher: IEEE
 
» The Dispersion of Nearest-Neighbor Decoding for Additive Non-Gaussian Channels
Abstract:
We study the second-order asymptotics of information transmission using random Gaussian codebooks and nearest neighbor decoding over a power-limited stationary memoryless additive non-Gaussian noise channel. We show that the dispersion term depends on the non-Gaussian noise only through its second and fourth moments, thus complementing the capacity result (Lapidoth, 1996), which depends only on the second moment. Furthermore, we characterize the second-order asymptotics of point-to-point codes over -sender interference networks with non-Gaussian additive noise. Specifically, we assume that each user’s codebook is Gaussian and that NN decoding is employed, i.e., that interference from the unintended users (Gaussian interfering signals) is treated as noise at each decoder. We show that while the first-order term in the asymptotic expansion of the maximum number of messages depends on the power of the interfering codewords only through their sum, this does not hold for the second-order term.
Autors: Jonathan Scarlett;Vincent Y. F. Tan;Giuseppe Durisi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 81 - 92
Publisher: IEEE
 
» The Effect of Drain Bias Stress on the Instability of Turned-OFF Amorphous HfInZnO Thin-Film Transistors Under Light Irradiation
Abstract:
A comprehensive study was done regarding stabilities under simultaneous stress of light and negative gate bias ()/positive drain bias () in amorphous hafnium-indium–zinc-oxide thin-film transistors. Negative threshold voltage () shift was observed in transfer characteristics after the stress. Through the consecutive stresses of ( V, V, and V) and ( V, V, and V) under light illumination, it is found that the negative shift is affected only by , because the drain current is determined by source-side energy barrier though drain-side energy band is locally lowered by -induced drain-side trapped holes. Furthermore, the drain-side trapped holes increase ON-current by reducing channel resistance after channel accumulation. Gate-to-drain capacitance () w- s measured before/after the ( V, V, and V) stress to clarify the presence and distribution of the drain-side trapped holes. From stretching out after the stress, it is revealed that the trapped holes introduce an additional capacitance by responding to the accumulated electrons and the capacitance is distributed according to the vertical electric field distribution of the stress.
Autors: Dae Woong Kwon;Jang Hyun Kim;Byung-Gook Park;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 153 - 158
Publisher: IEEE
 
» The Effects of Inter-Symbol Interference in Dynamic Element Matching DACs
Abstract:
Dynamic element matching (DEM) is often applied to multi-bit DACs to avoid nonlinear distortion that would otherwise result from inevitable mismatches among nominally identical circuit elements. Unfortunately, for such a DEM DAC to fully achieve this objective its constituent 1-bit DACs must be free of inter-symbol interference (ISI), i.e., the error from each 1-bit DAC must not depend on prior samples of the DAC's input sequence. This paper provides the first quantitative general analysis of the effects of ISI on the continuous-time outputs of DEM DACs. The analysis provides some surprising insights such as the conclusion that for certain types of DEM the only nonlinear distortion caused by ISI is second-order distortion. The paper also presents a digital pre-distortion technique that cancels the second-order distortion in the DEM DAC's first Nyquist band if information about the 1-bit DAC mismatches is available.
Autors: Jason Remple;Ian Galton;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 14 - 23
Publisher: IEEE
 
» The Emergence of Edge Computing
Abstract:
Industry investment and research interest in edge computing, in which computing and storage nodes are placed at the Internet's edge in close proximity to mobile devices or sensors, have grown dramatically in recent years. This emerging technology promises to deliver highly responsive cloud services for mobile computing, scalability and privacy-policy enforcement for the Internet of Things, and the ability to mask transient cloud outages. The web extra at www.youtube.com/playlist?list=PLmrZVvFtthdP3fwHPy_4d61oDvQY_RBgS includes a five-video playlist demonstrating proof-of-concept implementations for three tasks: assembling 2D Lego models, freehand sketching, and playing Ping-Pong.
Autors: Mahadev Satyanarayanan;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 30 - 39
Publisher: IEEE
 
» The Future of Pervasive Health
Abstract:
During the May 2016 Pervasive Health Conference Workshop, participants identified five general themes related to pervasive health solutions that must be addressed: technological challenges and opportunities, adoption and adherence, open data, methods and ethical issues, and education. Here, the authors discuss each of these themes in more detail.
Autors: Kay Connelly;Oscar Mayora;Jesus Favela;Maia Jacobs;Aleksandar Matic;Chris Nugent;Stefan Wagner;
Appeared in: IEEE Pervasive Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 16 - 20
Publisher: IEEE
 
» The Generalized Sinusoidal Frequency-Modulated Waveform for Active Sonar
Abstract:
Pulse compression (PC) active sonar waveforms provide a significant improvement in range resolution over single-frequency sinusoidal waveforms also known as continuous wave (CW) waveforms. Since their inception in the 1940s, a wide variety of PC waveforms have been designed using either frequency modulation (FM), phase coding, or frequency hopping to suite particular sonar applications. The sinusoidal FM (SFM) waveform modulates its instantaneous frequency (IF) by a sinusoid to achieve high Doppler sensitivity which also aids in suppressing reverberation. This allows the SFM waveform to resolve target velocities. While the SFM's resolution in range is inversely proportional to its bandwidth, the SFM's autocorrelation function (ACF) contains many large sidelobes. The periodicity of the SFM's IF creates these sidelobes and impairs the SFM's ability to clearly distinguish multiple targets in range. This paper describes a generalization of the SFM waveform, referred to as the generalized SFM (GSFM) waveform, which modifies the SFM's IF to resemble the time/voltage characteristic of an FM chirp waveform. As a result of this modification, the Doppler sensitivity of the SFM is preserved while substantially reducing the high range sidelobes, producing a waveform whose ambiguity function (AF) approaches a thumbtack shape. This paper focuses primarily on the properties of the GSFM's thumbtack AF shape and compares it to other well-known waveforms with a similar AF shape. The GSFM waveform achieves zero range-Doppler coupling for single target measurements which in turn minimizes the variance in jointly estimating target range and velocity and optimizes resolution of multiple point targets in range and velocity. The GSFM's AF peak sidelobe levels, which determine the waveform's ability to detect weak targets in the presence of- strong ones, are comparable to other well-established thumbtack AF waveforms such as Costas or phase-coded waveforms over a wide range of time-bandwidth product (TBP) values.
Autors: David A. Hague;John R. Buck;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 109 - 123
Publisher: IEEE
 
» The High-Frequency Coastal Radar Network Operated by Puertos del Estado (Spain): Roadmap to a Fully Operational Implementation
Abstract:
In this paper, a detailed description of the roadmap to transform four individual CODAR SeaSonde high-frequency (HF) radars into an integrated HF radar network operated by Puertos del Estado (Madrid, Spain) is provided. To assess the maturation process into a fully operational status, the system must evolve via an implementation of phased approaches, including: homogenization of maintenance practices, quality control checks in real time, standardization of data access, and development of customized visualization tools. Additionally, continuous validation works with independent in situ sensors are required to provide upper bounds on both radial and total radar current measurement accuracies. Consistent correlation coefficients and uncertainty values emerge in the range of 0.31–0.81 and 8–22 cm/s, respectively, for the remotely estimated velocities. Complementarily, a dedicated online website has been developed to operationally monitor radar system health in real time. This automated quality control application analyzes a number of diagnose parameters to obtain estimates of their standard ranges and evaluate radar site performance according to them. Abrupt changes, gradual degradation, and/or failure problems can be easily detected, triggering alerts for troubleshooting. Once a good performance of HF radar systems is ensured, 2-D surface current maps are used for a broad range of practical applications, i.e., search-and-rescue operations, oil spill response, or the rigorous skill assessment of an operational ocean forecasting system such as Iberia–Biscay–Ireland (IBI), implemented within the frame of the Copernicus Marine Environment Monitoring Service.
Autors: Pablo Lorente;Silvia Piedracoba Varela;Javier Soto-Navarro;Maria Isabel Ruiz;Enrique Álvarez-Fanjul;Pedro Montero;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 56 - 72
Publisher: IEEE
 
» The History of Magna-Power Electronics: The Path to a Vertically Integrated U.S. Electronics Manufacturer [History]
Abstract:
Magna-Power Electronics (MPE) was founded in 1981 with the intent of being a power electronics, lighting, and magnetics research and development (R&D) company. The company and its founder's career pivoted several times before settling into its niche of engineering, manufacturing, and selling high-power sources and loads. This article chronicles the milestones in the company's history that have defined its eventual path to success.
Autors: Adam Pitel;Grant Pitel;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jan 2017, volume: 23, issue:1, pages: 7 - 13
Publisher: IEEE
 
» The Impact of Operating Reserves on Investment Planning of Renewable Power Systems
Abstract:
To limit computational effort, current power system expansion planning tools typically consider limited detail on the technical constraints of power systems, such as the need for operating reserves. With growing balancing needs, this is likely to underestimate the technical barriers and integration cost of large shares of renewable generation. This contribution studies the impact of operating reserve requirements on generation capacity investments following the large-scale integration of intermittent renewable generation. Simulations show that operating reserves have a substantial impact on the generation capacity installed, and its operation, and result in a substantial increase of renewable integration costs. Furthermore, it is shown that the use of improved reserve strategies, such as dynamic reserve sizing, and the participation of renewables in the supply of downward reserves, is able to significantly reduce this cost increase.
Autors: Arne van Stiphout;Kristof De Vos;Geert Deconinck;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 378 - 388
Publisher: IEEE
 
» The Impossible Thing
Abstract:
In this inaugural column, the author ponders the autonomous cars of tomorrow.
Autors: Brian David Johnson;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 71 - 71
Publisher: IEEE
 
» The Interaction Between Schema Matching and Record Matching in Data Integration
Abstract:
Schema Matching (SM) and Record Matching (RM) are two necessary steps in integrating multiple relational tables of different schemas, where SM unifies the schemas and RM detects records referring to the same real-world entity. The two processes have been thoroughly studied separately, but few attention has been paid to the interaction of SM and RM. In this work, we find that, even alternating them in a simple manner, SM and RM can benefit from each other to reach a better integration performance (i.e., in terms of precision and recall). Therefore, combining SM and RM is a promising solution for improving data integration. To this end, we define novel matching rules for SM and RM, respectively, that is, every SM decision is made based on intermediate RM results, and vice versa, such that SM and RM can be performed alternately. The quality of integration is guaranteed by a Matching Likelihood Estimation model and the control of semantic drift, which prevent the effect of mismatch magnification. To reduce the computational cost, we design an index structure based on q-grams and a greedy search algorithm that can reduce around 90 percent overhead of the interaction. Extensive experiments on three data collections show that the combination and interaction between SM and RM significantly outperforms previous works that conduct SM and RM separately.
Autors: Binbin Gu;Zhixu Li;Xiangliang Zhang;An Liu;Guanfeng Liu;Kai Zheng;Lei Zhao;Xiaofang Zhou;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2017, volume: 29, issue:1, pages: 186 - 199
Publisher: IEEE
 
» The Kolmogorov–Zakharov Model for Optical Fiber Communication
Abstract:
A mathematical framework is presented to study the evolution of multi-point cumulants in nonlinear dispersive partial differential equations with random input data, based on the theory of weak wave turbulence (WWT). This framework is used to explain how energy is distributed among Fourier modes in the nonlinear Schrödinger equation. This is achieved by considering interactions among four Fourier modes and studying the role of the resonant, non-resonant, and trivial quartets in the dynamics. As an application, a power spectral density is suggested for calculating the interference power in dense wavelength-division multiplexed optical systems, based on the kinetic equation of the WWT. This power spectrum, termed the Kolmogorov-Zakharov (KZ) model, results in a better estimate of the signal spectrum in optical fiber, compared with the so-called Gaussian noise model. The KZ model is generalized to non-stationary inputs and multi-span optical systems.
Autors: Mansoor I. Yousefi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 377 - 391
Publisher: IEEE
 
» The Motion Characteristics of a Single Cathode Spot in Removing Oxide Layer on Metal Surface by Vacuum Arc
Abstract:
The motion of cathode spots plays a crucial important role in removing oxide layer on a metal surface by vacuum arc. In this paper, the characteristics of the motion of a single cathode spot on metal surface with oxide layer are investigated experimentally. Experiments are conducted in a detachable vacuum chamber. A hollow copper anode with a hole of mm is used in order to observe the 2-D motion of the cathode spot. The motion of the cathode spot during the descaling process is photographed by a high-speed digital camera with an exposure time of . Experimental results indicate that there are slow motion and fast motion of the cathode spot during descaling process, and the slow motion is the basic characteristic in most of the descaling time. The probability distribution of the cathode spot’s displacement and resident time, the average velocity, and the movement parameter are analyzed quantitatively. The results indicate that with the increase of gap distance or the decrease of oxide layer thickness, the cathode spot becomes more active.
Autors: Wenhui Li;Zongqian Shi;Cong Wang;Fei Shi;Shenli Jia;Lijun Wang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 106 - 112
Publisher: IEEE
 
» The NTP Cell Phone RF Radiation Health Effects Project [Health Matters]
Abstract:
On 26 May 2016, a U.S.-government-led project reported occurrences of two types of rare cancers in laboratory rats exposed to RF radiation used for wireless cell phone operations. This five-year project has been ongoing for more than ten years. It is the largest health effects study ever undertaken by the National Toxicology Program (NTP) of the National Institute of Environmental Health Sciences (NIEHS). Presents the results and findings of this study.
Autors: James C. Lin;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 15 - 17
Publisher: IEEE
 
» The Sky's the Limit: A Switchable RF-MEMS Filter Design for Wireless Avionics Intracommunication
Abstract:
The switchable RF-microelectromechanical systems (MEMS) filter described in this article was presented as part of the student design competitions at the 2016 IEEE Microwave Theory and Techniques Society (MTT-S) International Microwave Symposium held in San Francisco in May 2016. The goal of this competition, sponsored by Technical Committee MTT-21, was to design a switchable filter to separate the industrial, scientific, and medical (i.e., ISM) band (2.4-2.5 GHz) from the wireless avionics intracommunication (WAIC) band (4.2-4.4 GHz). The upcoming availability of the 4.2-4.4 GHz band for WAIC to implement wireless connectivity inside passenger aircraft cabins provided the main motivation for this design, and the filter footprint was the most important requirement.
Autors: Desireh Shojaei-Asanjan;Raafat R. Mansour;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 100 - 106
Publisher: IEEE
 
» The Technology Behind Personal Digital Assistants: An overview of the system architecture and key components
Abstract:
We have long envisioned that one day computers will understand natural language and anticipate what we need, when and where we need it, and proactively complete tasks on our behalf. As computers get smaller and more pervasive, how humans interact with them is becoming a crucial issue. Despite numerous attempts over the past 30 years to make language understanding (LU) an effective and robust natural user interface for computer interaction, success has been limited and scoped to applications that were not particularly central to everyday use. However, speech recognition and machine learning have continued to be refined, and structured data served by applications and content providers has emerged. These advances, along with increased computational power, have broadened the application of natural LU to a wide spectrum of everyday tasks that are central to a user's productivity. We believe that as computers become smaller and more ubiquitous [e.g., wearables and Internet of Things (IoT)], and the number of applications increases, both system-initiated and user-initiated task completion across various applications and web services will become indispensable for personal life management and work productivity. In this article, we give an overview of personal digital assistants (PDAs); describe the system architecture, key components, and technology behind them; and discuss their future potential to fully redefine human?computer interaction.
Autors: Ruhi Sarikaya;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 67 - 81
Publisher: IEEE
 
» The Three-Terminal Interactive Lossy Source Coding Problem
Abstract:
In this paper, we explore the three-node multi-terminal lossy source coding problem, which seems to offer a formidable mathematical complexity. We derive an inner bound to the general rate-distortion region of this problem, which is a natural extension of the seminal work by Kaspi on the interactive two-terminal source coding problem. It is shown that this (rather involved) inner bound contains several rate-distortion regions of some relevant source coding settings. In this way, besides the non-trivial extension of the interactive two terminal problem, our results can be seen as a generalization and hence unification of several previous works in the field. By specializing the inner bound to particular cases, we obtain some novel rate-distortion regions for several multi-terminal lossy source coding problems.
Autors: Leonardo Rey Vega;Pablo Piantanida;Alfred O. Hero;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 532 - 562
Publisher: IEEE
 
» Theoretical Investigation of Efficient Green Tunnel-Junction Light-Emitting Diodes
Abstract:
Green tunnel-junction (TJ) light-emitting diodes (LEDs) are investigated theoretically in this letter. The influence of Auger recombination on the optical performance of green single LED and TJ LED is explored. Simulation results show that non-uniform carrier distribution and Auger recombination are critical issues influencing the performance of conventional green LED. The TJ LED can be operated at relatively low current density that possesses suppressed Auger recombination and high quantum efficiency when compared with its single LED counterpart at the same level of output power. Simulated wall-plug efficiency of the TJ LEDs with two and three unit LEDs is increased from 5.67% to 10.51% and 12.54%, respectively, in comparison with the single LED when the output power is 21 mW.
Autors: Yen-Kuang Kuo;Ya-Hsuan Shih;Jih-Yuan Chang;Fang-Ming Chen;Ming-Lun Lee;Jinn-Kong Sheu;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 75 - 78
Publisher: IEEE
 
» Theoretical Research on the Thermal-Lens Effect of Magnetic Fluid by Using Brownian Dynamics Method
Abstract:
Magnetic fluid has not only rich optical properties, but also interesting thermal-lens effect. The thermal-lens effect of magnetic fluid was studied by using the Brownian dynamics method. The Theoretical simulation and analysis were taken to research the whole generation process of thermal-lens effect. The thermal-lens effect generation of water-based magnetic fluid irradiated by the laser of different optical powers was studied in microscopic view. Based on the model of the thermal-lens effect, Monte Carlo method and Kirchhoff diffraction theory were adopted to simulate and analyze the far-field diffraction ring pattern generated by a Gauss light beam passing through the magnetic fluid. Then, the influences of different central temperatures of the magnetic fluid to the ring numbers, width, and intensity distribution of far-field diffraction ring pattern were obtained. The results were verified with the published experimental results.
Autors: Ri-Qing Lv;Yong Zhao;Jin Li;Ya-Nan Zhang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 7
Publisher: IEEE
 
» Thermal Effect on Attenuation and Luminescence of Bi/Er Co-Doped Fiber
Abstract:
We investigated thermal effect on attenuation and luminescence of Bi/Er co-doped fiber (BEDF). A strong and irreversible thermal darkening effect in both near-infrared (NIR) and visible spectral range was observed, accompanied by a luminescence quenching of bismuth active centers (BACs), in temperature range from 600 °C to 800 °C. This thermal darkening effect is believed to be linked to the precipitation of metallic bismuth nanoparticles and takes place at a relatively low temperature. We also observed that the quenching of BAC-Si in the BEDF is more prominent than other BACs. The BAC-Si related emission at 1420 nm is decreased by 80% when the temperature is increased to 600 °C—before the significant thermal darkening occurs and while the quenching of others BACs is not significant.
Autors: Shuen Wei;Yanhua Luo;Mingjie Ding;Fangfang Cai;Gui Xiao;Desheng Fan;Qiancheng Zhao;Gang-Ding Peng;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 43 - 46
Publisher: IEEE
 
» Thermoradiative Energy Conversion With Quasi-Fermi Level Variations
Abstract:
An extension of the detailed balance method for the thermoradiative conversion, including the transport properties, is presented in this paper. This formalism is applied to the study of the most important properties (maximum output power, the efficiency at which that power is delivered, and the maximum efficiency) of thermoradiative cells (TRCs) with bandgap values between 0.2 and 0.7 eV. The calculations demonstrate that the consideration of the electronic transport in the calculation of the properties of the TRCs leads to predict better working properties for them.
Autors: Julio J. Fernández;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 250 - 255
Publisher: IEEE
 
» Thickness Engineered Tunnel Field-Effect Transistors Based on Phosphorene
Abstract:
Thickness engineered tunneling field-effect transistors (TE-TFET) as a high-performance ultra-scaled steep transistor is proposed. This device exploits a specific property of 2-D materials: layer thickness-dependent energy bandgaps (). Unlike the conventional hetero-junction TFETs, TE-TFET uses spatially varying layer thickness to form a hetero-junction. This offers advantages by avoiding the lattice mismatch problems at the interface. Furthermore, it boosts the ON-current to with 15-nm channel length. Providing higher ON currents, phosphorene TE-TFET outperforms the homojunction phosphorene and the TMD TFETs in terms of extrinsic energy-delay product. TE-TFET also scales well to 9 nm with constant field scaling mV/nm. In this letter, the operation principles of TE-TFET and its performance sensitivity to the design parameters are investigated through full-band atomistic quantum transport simulations.
Autors: Fan W. Chen;Hesameddin Ilatikhameneh;Tarek A. Ameen;Gerhard Klimeck;Rajib Rahman;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 130 - 133
Publisher: IEEE
 
» Third IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization [Conference Report]
Abstract:
Presents information on the Third IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization.
Autors: Yanli Cai;Hsien-Shun Wu;Ching-Kuang Clive Tzuang;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 126 - 140
Publisher: IEEE
 
» Three-Dimensional Imaging Method Incorporating Range Points Migration and Doppler Velocity Estimation for UWB Millimeter-Wave Radar
Abstract:
High-resolution, short-range sensors that can be applied in optically challenging environments (e.g., in the presence of clouds, fog, and/or dark smog) are in high demand. Ultrawideband (UWB) millimeter-wave radars are one of the most promising devices for the above-mentioned applications. For target recognition using sensors, it is necessary to convert observational data into full 3-D images with both time efficiency and high accuracy. For such conversion algorithm, we have already proposed the range points migration (RPM) method. However, in the existence of multiple separated objects, this method suffers from inaccuracy and high computational cost due to dealing with many observed RPs. To address this issue, this letter introduces Doppler-based RPs clustering into the RPM method. The results from numerical simulations, assuming 140-GHz band millimeter radars, show that the addition of Doppler velocity into the RPM method results in more accurate 3-D images with reducing computational costs.
Autors: Yuta Sasaki;Fang Shang;Shouhei Kidera;Tetsuo Kirimoto;Kenshi Saho;Toru Sato;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 122 - 126
Publisher: IEEE
 
» Throughput Analysis of Decentralized Coded Content Caching in Cellular Networks
Abstract:
Decentralized coded content caching for next generation cellular networks is studied. The contents are linearly combined and cached in under-utilized caches of user terminals and its throughput capacity is compared with decentralized uncoded content caching. In both scenarios, we consider multihop device-to-device communications and the use of femtocaches in the network. It is shown that decentralized coded content caching can increase the network throughput capacity compared to decentralized uncoded caching by reducing the number of hops needed to deliver the desired content. Furthermore, the throughput capacity for Zipfian content request distribution is computed and it is shown that the decentralized coded content cache placement can increase the throughput capacity of cellular networks by a factor of where is the number of nodes served by a femtocache.
Autors: Mohsen Karimzadeh Kiskani;Hamid R. Sadjadpour;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 663 - 672
Publisher: IEEE
 
» Throughput-Efficient Super-TDMA MAC Transmission Schedules in Ad Hoc Linear Underwater Acoustic Networks
Abstract:
Underwater acoustic (UWA) sensor network deployments may be used in many applications for environmental, scientific, military, and commercial purposes. Several topologies are in use, but the most widely used topology is linear. Indeed, placing nodes on a single line offers more opportunities in terms of large coverage and high-rate services. The UWA channel is a shared medium. Thus, a medium access control (MAC) protocol is necessary, primarily to regulate and coordinate nodes’ access. MAC protocol design should take into consideration large propagation delays to favor better network throughput. Performance of most developed protocols in linear topologies does not exceed 1 in terms of normalized network throughput, or equivalently, channel utilization. We explore transmission schedules in three important contexts. 1) Single collision domain with unicast traffic. In an -node network, we develop transmission schedules achieving a normalized network throughput of . This is the best that can be done in such a context, as demonstrated using a general greedy approach combined with an exhaustive search for small-size networks. 2) Single collision domain with broadcast traffic. We propose a periodic per-node fair schedule with the shortest period. Achievable throughput in such conditions is close to . Likewise, we prove that the throughput is upper bounded by under the per-node fairness constraint. 3) Partially overlapping collision domains with unicast traffic. We consider a simple illustration of such a configuration. The proposed transmission schedule depicts a scenario where messages origi- ate at one end of the network, and are sequentially relayed node by node (i.e., hop by hop) in the direction of the final destination located at the other end of the network. Furthermore, for all three discussed contexts, we build up computationally efficient algorithms that generate transmission schedules regardless of network size. We explore the idea of exploiting nonzero propagation delays for linear topologies to improve network throughput. In recent UWA sensor networks, the linear topology is a fundamental component that may be used to build more complex network configurations. This study would then serve as a base for future research into this area.
Autors: Said Lmai;Mandar Chitre;Christophe Laot;Sebastien Houcke;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 156 - 174
Publisher: IEEE
 
» Time Series-Oriented Load Prediction Model and Migration Policies for Distributed Simulation Systems
Abstract:
HLA-based simulation systems are prone to load imbalances due to lack management of shared resources in distributed environments. Such imbalances lead these simulations to exhibit performance loss in terms of execution time. As a result, many dynamic load balancing systems have been introduced to manage distributed load. These systems use specific methods, depending on load or application characteristics, to perform the required balancing. Load prediction is a technique that has been used extensively to enhance load redistribution heuristics towards preventing load imbalances. In this paper, several efficient Time Series model variants are presented and used to enhance prediction precision for large-scale distributed simulation-based systems. These variants are proposed to extend and correct the issues originating from the implementation of Holt’s model for time series in the predictive module of a dynamic load balancing system for HLA-based distributed simulations. A set of migration decision-making techniques is also proposed to enable a prediction-based load balancing system to be independent of any prediction model, promoting a more modular construction.
Autors: Robson Eduardo De Grande;Azzedine Boukerche;Raed Alkharboush;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 215 - 229
Publisher: IEEE
 
» Time-Delay Mapping of High-Resolution Gastric Slow-Wave Activity
Abstract:
Goal: Analytic monitoring of electrophysiological data has become an essential component of efficient and accurate clinical care. In the gastrointestinal (GI) field, recent advances in high-resolution (HR) mapping are now providing critical information about spatiotemporal profiles of slow-wave activity in normal and disease (dysrhythmic) states. The current approach to analyze GI HR electrophysiology data involves the identification of individual slow-wave events in the electrode array, followed by tracking and clustering of events to create a spatiotemporal map. This method is labor and computationally intensive and is not well suited for real-time clinical use or chronic monitoring. Methods: In this study, an automated novel technique to assess propagation patterns was developed. The method utilized time delays of the slow-wave signals which was computed through cross correlations to calculate velocity. Validation was performed with both synthetic and human and porcine experimental data. Results: The slow-wave profiles computed via the time-delay method compared closely with those computed using the traditional method (speed difference: 7.2% ± 2.6%; amplitude difference: 8.6% ± 3.5%, and negligible angle difference). Conclusion: This novel method provides rapid and intuitive analysis and visualization of slow-wave activity. Significance: This techniques will find major applications in the clinical translation of acute and chronic HR electrical mapping for motility disorders, and act as a screening tool for detailed detection and tracking of individual propagating wavefronts, without the need for comprehensive standard event-detection analysis.
Autors: Niranchan Paskaranandavadivel;Gregory O'Grady;Leo K. Cheng;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 166 - 172
Publisher: IEEE
 
» Time-Domain Line-Integral Representations of Physical-Optics Scattered Fields
Abstract:
A time-domain (TD) line-integral (LI) representation of the physical-optics (PO) radiation integral is developed for the scattering from a perfectly conducting surface illuminated by an electric Hertzian dipole. The proposed LI representation, which is valid and singularity-free for all near-field observers, is derived directly in the TD by introducing dyad potentials. This TD representation can be further expressed in terms of geometric-optics and boundary-wave components of the scattering mechanisms, as in the conventional frequency-domain LI representations. Using the proposed LI representation, the computational complexity is reduced by an order of the scatterer’s linear electric size, compared with the straightforward numerical quadrature of the PO surface integral. Simple and complicated numerical examples are presented to demonstrate the efficiency and accuracy of the proposed TD-LI algorithm.
Autors: Tian Tian Fan;Xiao Zhou;Wen Ming Yu;Xiao Yang Zhou;Tie Jun Cui;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 309 - 318
Publisher: IEEE
 
» Time-Reversibility for Real-Time Scheduling on Multiprocessor Systems
Abstract:
The real-time systems community has widely studied real-time scheduling, focusing on how to guarantee schedulability (i.e., timely execution) of a set of real-time tasks. However, there still exist a number of task sets that are actually schedulable by a target scheduling algorithm, but proven schedulable by none of existing schedulability tests, especially on a multiprocessor. In this paper, we propose a new paradigm for real-time scheduling, called time-reversibility, which views real-time scheduling under a change in the sign of time , and present how to utilize the paradigm for schedulability improvement. To this end, we first define the notion of a time-reversed scheduling algorithm and a time-reversible schedulability test ; for example, the time-reversed scheduling algorithm against Earliest Deadline First (EDF) is Latest Release-time First (LRF). Then, we develop time-reversibility theories for schedulability improvement, which utilizes the definitions so as to compose schedulability. Finally, we generalize the definitions and theories to job-level dynamic-priority scheduling in which the priority of a job may vary with time, such as Earliest Deadline first until Zero Laxity (EDZL). Specifically, we accommodate time-varying job parameters to the time-reversibility definitions, and adapt the time-reversibility theories for the additional necessary deadline-miss conditions specialized for a class of job-level dynamic-priority scheduling algorithms. As case studies, we demonstrate that the time-reversibility theories help to find up to 13.6 percent additional EDF- and EDZL-schedulable task sets.
Autors: Jinkyu Lee;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 230 - 243
Publisher: IEEE
 
» Time-Variant Frequency Response Function Measurement of Multivariate Time-Variant Systems Operating in Feedback
Abstract:
The classical time-invariance assumption is often not (exactly) met in real-life applications. As a natural extension of the frequency response function (FRF), the time-variant FRF (TV-FRF) provides quick insight into the complex dynamics of time-variant systems. Recently, a procedure has been proposed to estimate nonparametrically the TV-FRF from known input, noisy output measurements of time-variant systems operating in open loop. However, in many applications, feedback is present either due to an explicit control action or due to the interaction between a nonideal actuator and the system under test. The extension of the open-loop approach to noisy input, noisy output measurements of time-variant systems operating in closed loop requires the deconvolution of the time-variant impulse response of the cascade of two time-variant systems. In this paper, this nontrivial problem is solved for a particular class of time-variant systems. The robustness of the approach with respect to the system assumption is demonstrated via simulations and measurements on an electronic circuit.
Autors: Rik Pintelon;Ebrahim Louarroudi;John Lataire;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 177 - 190
Publisher: IEEE
 
» Timed Automata Modeling and Verification for Publish-Subscribe Structures Using Distributed Resources
Abstract:
In this paper we present a Timed Automata model for the Publish/Subscribe paradigm in the context of Web Service Compositions with distributed resources, on the basis of an algebraic language inspired by the WSRF standard constructions. This framework allows a set of participants in a Web Service composition to interact with one another and also to manage a collection of distributed resources. The model includes operations for clients to publish, discover and subscribe to resources, so as to be notified when the resource property values fulfill certain conditions (topic-based subscription). Simulation and model-checking techniques can therefore be applied to the obtained network of timed automata, in order to check whether certain properties of interest are satisfied. A specific case study is finally presented to illustrate the model and the verification of the relevant properties on the obtained timed automata model.
Autors: Valentín Valero;Gregorio Díaz;María-Emilia Cambronero;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Jan 2017, volume: 43, issue:1, pages: 76 - 99
Publisher: IEEE
 
» Timing Analysis of Tasks on Runtime Reconfigurable Processors
Abstract:
Real-time embedded systems need to be analyzable for timing guarantees. Despite significant scientific advances, however, timing analysis lags years behind current microarchitectures with out-of-order scheduling pipelines, several hardware threads, and multiple (shared) cache layers. To satisfy the increasing performance demands, analyzable performance features are required. We propose a novel timing analysis approach to introduce runtime reconfigurable instruction set processors as one way to escape the scarcity of analyzable performance while preserving the flexibility of the system. We introduce extensions to the state-of-the-art Integer linear programming (ILP)-based program path analysis for computing precise worst case time bounds in the presence of the widely used technique to continue processor execution during reconfiguration by emulating not yet reconfigured custom instructions (CIs) in software. We identify and safely bound a timing anomaly of runtime reconfiguration, where executing faster than worst case time during reconfiguration extends the execution time of the whole program. Stalling the processor during reconfiguration (easier to analyze but not state-of-the-art for reconfigurable processors) is not required in our approach. Finally, we show the precision of our analysis on a complex multimedia application with multiple reconfigurable CIs for several hardware parameters and give advice on how to deal with reconfiguration delay under timing guarantees.
Autors: Marvin Damschen;Lars Bauer;Jörg Henkel;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 294 - 307
Publisher: IEEE
 
» TiO2-Based Thick Film pH Sensor
Abstract:
Miniaturized electrochemical pH sensors are increasingly in demand for applications such as online monitoring of water quality and health monitoring. The metal oxides are the best candidates for sensing electrodes of such sensors as they offer high chemical stability. In this paper, we present a novel approach to obtain interdigitated conductimetric pH sensor using screen printing of TiO2 thick film on an alumina substrate. The microstructural and crystalline properties of the TiO2 sensitive film were examined with scanning electron microscopy and Raman spectroscopy. The impedance spectroscopic studies of the fabricated thick film sensor were carried out in the frequency range of 5–20 kHz for the test solutions in the pH range of 4–10 and it was observed that the impedance of the film is distinctly dependent on pH. Using the measured impedance data, we have also proposed an equivalent RC network model for the fabricated pH sensor. The physical meaning of the model parameters was determined by electrochemical impedance spectroscopic analysis, and through statistical analysis it was found that all parameters are distinctly pH-dependent.
Autors: Mitar Simić;Libu Manjakkal;Krzysztof Zaraska;Goran M. Stojanović;Ravinder Dahiya;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 248 - 255
Publisher: IEEE
 
» TJBot and Zooids: The Connection between Pervasive Computing and AI
Abstract:
Pervasive computing and artificial intelligence have amazing potential to reshape how humans interact with computers.
Autors: Maria R. Ebling;
Appeared in: IEEE Pervasive Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 2 - 4
Publisher: IEEE
 
» Torque Analysis on a Double Rotor Electrical Variable Transmission With Hybrid Excitation
Abstract:
An electrical variable transmission (EVT) can be used as a power splitting device in hybrid electrical vehicles. The EVT analyzed in this paper is a rotating field electrical machine having two concentric rotors. On the outer rotor, permanent magnets (PMs) are combined with a dc-field winding, being the first implementation of its kind. The magnetic field in the machine as well as the electromagnetic torque on both rotors are a function of the q- and d-axis currents of the stator and inner rotor, as well as the dc-field current. To describe and fully understand this multiple-input multiple-output machine, this paper gives an overview of the influence of the different current inputs on the flux linkage and torque on both rotors. Focus is given to the hybrid excitation in the d-axis by combining the dc-field current and the alternating currents. This has the advantage compared to other EVT topologies that unwanted stator torque can be avoided without stator d-axis current flux weakening. Results of the analysis are presented by means of the torque to current characteristics of a double rotor PM-assisted EVT, as well as the torque to current ratios. The machine characteristics are finally experimentally verified on a prototype machine.
Autors: Joachim Druant;Hendrik Vansompel;Frederik De Belie;Jan Melkebeek;Peter Sergeant;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 60 - 68
Publisher: IEEE
 
» Toward a Wearable RFID System for Real-Time Activity Recognition Using Radio Patterns
Abstract:
Elderly care is one of the many applications supported by real-time activity recognition systems. Traditional approaches use cameras, body sensor networks, or radio patterns from various sources for activity recognition. However, these approaches are limited due to ease-of-use, coverage, or privacy preserving issues. In this paper, we present a novel wearable Radio Frequency Identification (RFID) system aims at providing an easy-to-use solution with high detection coverage. Our system uses passive tags which are maintenance-free and can be embedded into the clothes to reduce the wearing and maintenance efforts. A small RFID reader is also worn on the user's body to extend the detection coverage as the user moves. We exploit RFID radio patterns and extract both spatial and temporal features to characterize various activities. We also address the issues of false negative of tag readings and tag/antenna calibration, and design a fast online recognition system. Antenna and tag selection is done automatically to explore the minimum number of devices required to achieve target accuracy. We develop a prototype system which consists of a wearable RFID system and a smartphone to demonstrate the working principles, and conduct experimental studies with four subjects over two weeks. The results show that our system achieves a high recognition accuracy of 93.6 percent with a latency of 5 seconds. Additionally, we show that the system only requires two antennas and four tagged body parts to achieve a high recognition accuracy of 85 percent.
Autors: Liang Wang;Tao Gu;Xianping Tao;Jian Lu;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 228 - 242
Publisher: IEEE
 
» Toward an Optimal Online Checkpoint Solution under a Two-Level HPC Checkpoint Model
Abstract:
The traditional single-level checkpointing method suffers from significant overhead on large-scale platforms. Hence, multilevel checkpointing protocols have been studied extensively in recent years. The multilevel checkpoint approach allows different levels of checkpoints to be set (each with different checkpoint overheads and recovery abilities), in order to further improve the fault tolerance performance of extreme-scale HPC applications. How to optimize the checkpoint intervals for each level, however, is an extremely difficult problem. In this paper, we construct an easy-to-use two-level checkpoint model. Checkpoint level 1 deals with errors with low checkpoint/recovery overheads such as transient memory errors, while checkpoint level 2 deals with hardware crashes such as node failures. Compared with previous optimization work, our new optimal checkpoint solution offers two improvements: (1) it is an online solution without requiring knowledge of the job length in advance, and (2) it shows that periodic patterns are optimal and determines the best pattern. We evaluate the proposed solution and compare it with the most up-to-date related approaches on an extreme-scale simulation testbed constructed based on a real HPC application execution. Simulation results show that our proposed solution outperforms other optimized solutions and can improve the performance significantly in some cases. Specifically, with the new solution the wall-clock time can be reduced by up to 25.3 percent over that of other state-of-the-art approaches. Finally, a brute-force comparison with all possible patterns shows that our solution is always within percent of the best pattern in the experiments.
Autors: Sheng Di;Yves Robert;Frédéric Vivien;Franck Cappello;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 244 - 259
Publisher: IEEE
 
» Toward Centimeter-Scale Human Activity Sensing with Wi-Fi Signals
Abstract:
By allowing centimeter-scale human activity sensing with Wi-Fi signals, the Fresnel zone model could revolutionize wireless sensing and Internet of Things applications. The web extra at www.youtube.com/watch?v=R_vR6O8706g demonstrates how the Fresnel zone model can be leveraged for device-free sensing of human activities such as respiration and walking.
Autors: Daqing Zhang;Hao Wang;Dan Wu;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 48 - 57
Publisher: IEEE
 
» Towards Optimal Control of Evolutionary Games on Networks
Abstract:
We investigate the control of evolutionary games on networks, in which each edge represents a two-player repeating game between neighboring agents. After each round of games, agents can imitate the strategies of better performing neighbors, while a subset of agents can be assigned strategies and thus serve as control inputs. We seek here the smallest set of control agents needed to drive the network to a desired uniform strategy state. After presenting exact solutions for complete and star networks and describing a general solution approach that is computationally practical only for small networks, we design a fast algorithm for approximating the solution on arbitrary networks using a weighted minimum spanning tree and strategy propagation algorithm. The resulting approximation is exact for certain classes of games on complete and star networks and simulations suggest that the algorithm performs well in more general cases.
Autors: James R. Riehl;Ming Cao;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 458 - 462
Publisher: IEEE
 
» Towards Quantitative Evaluation of Tissue Absorption Coefficients Using Light Fluence Correction in Optoacoustic Tomography
Abstract:
Optoacoustic tomography is a fast developing imaging modality, combining the high contrast available from optical excitation of tissue with the high resolution and penetration depth of ultrasound detection. Light is subject to both absorption and scattering when traveling through tissue; adequate knowledge of tissue optical properties and hence the spatial fluence distribution is required to create an optoacoustic image that is directly proportional to chromophore concentrations at all depths. Using data from a commercial multispectral optoacoustic tomography (MSOT) system, we implemented an iterative optimization for fluence correction based on a finite-element implementation of the delta-Eddington approximation to the Radiative Transfer Equation (RTE). We demonstrate a linear relationship between the image intensity and absorption coefficients across multiple wavelengths and depths in phantoms. We also demonstrate improved feature visibility and spectral recovery at depth in phantoms and with in vivo measurements, suggesting our approach could in the future enable quantitative extraction of tissue absorption coefficients in biological tissue.
Autors: Frederic M. Brochu;Joanna Brunker;James Joseph;Michal R. Tomaszewski;Stefan Morscher;Sarah E. Bohndiek;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 322 - 331
Publisher: IEEE
 
» Towards the Tradeoffs in Designing Data Center Network Architectures
Abstract:
Existing Data Center Network (DCN) architectures are classified into two categories: switch-centric and server-centric architectures. In switch-centric DCNs, routing intelligence is placed on switches; each server usually uses only one port of the Network Interface Card (NIC) to connect to the network. In server-centric DCNs, switches are only used as cross-bars, and routing intelligence is placed on servers, where multiple NIC ports may be used. In this paper, we formally introduce a new category of DCN architectures: the dual-centric DCN architectures, where routing intelligence can be placed on both switches and servers. The dual-centric philosophy can achieve various tradeoffs in designing DCN architectures. We propose three novel dual-centric DCN architectures: FCell, FRectangle, and FSquare, all of which are based on the folded Clos topology. FCell is a power-efficient DCN architecture, with a larger diameter and lower bisection bandwidth than FSquare and FRectangle. FSquare is a high performance DCN architecture, in which the diameter is small and the bisection bandwidth is large; however, the DCN power consumption per server in FSquare is high. FRectangle significantly reduces the DCN power consumption per server, compared to FSquare, at the sacrifice of some networking performances. By investigating FCell, FRectangle and FSquare, and by comparing them with existing architectures, we demonstrate that, the three novel dual-centric architectures enjoy the advantages of both switch-centric designs and server-centric designs, have various nice properties for practical data centers, and provide flexible tradeoff choices in designing DCN architectures.
Autors: Dawei Li;Jie Wu;Zhiyong Liu;Fa Zhang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 260 - 273
Publisher: IEEE
 
» Transactive Control of Commercial Buildings for Demand Response
Abstract:
Transactive control is a type of distributed control strategy that uses market mechanisms to engage self-interested responsive loads to achieve power balance in the electrical power grid. In this paper, we propose a transactive control approach of commercial building heating, ventilation, and air-conditioning (HVAC) systems for demand response. We first describe the system models, and identify their model parameters using data collected from systems engineering building (SEB) located on our Pacific Northwest National Laboratory campus. We next present a transactive control market structure for commercial building HVAC systems, and describe its agent bidding and market clearing strategies. Several case studies are performed in a simulation environment using building controls virtual test bed (BCVTB) and calibrated SEB EnergyPlus model. We show that the proposed transactive control approach is very effective at peak shaving, load shifting, and strategic conservation for commercial building HVAC systems.
Autors: He Hao;Charles D. Corbin;Karanjit Kalsi;Robert G. Pratt;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 774 - 783
Publisher: IEEE
 

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