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Electrical and Electronics Engineering publications abstract of: 05-2016 sorted by title, page: 0

» 1-MHz LLC Resonant DC Transformer (DCX) With Regulating Capability
Abstract:
This paper presents an MHz LLC resonant converter with load-regulating capability. Unlike the two-stage solution, most of input power is delivered to the load directly by the main transformer in the proposed topology. Moreover, only small portion of input power is converted by two stages: 1) auxiliary transformer and 2) a cascaded PWM dc-dc converter. Therefore, the sacrifice of the efficiency caused by the two-stage conversion is minimized. The operating principle of the proposed converter is analyzed, and a 1-MHz prototype based on the proposed converter is built-up to verify the high-frequency, high-efficiency, and output-regulating capability.
Autors: Wu, X.;Chen, H.;Qian, Z.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2904 - 2912
Publisher: IEEE
 
» 12CaO.7Al O Ceramic: A Review of the Electronic and Optoelectronic Applications in Display Devices
Abstract:
The alumina-based compound, 12CaO.7Al2O3, is a ceramic material with a unique cage-like lattice. Such a structure has enabled scientists to extract various new characteristics from this compound, most of which were unknown until quite recently. This compound has the ability to incorporate different anionic species and even electrons to the empty space inside its cages, thereby changing from an insulator into a conductive oxide. The cage walls can also incorporate different rare earth phosphor elements producing an oxide-based phosphor. All these characteristics are obtained without a significant change in the structure of the lattice. It is, therefore, reasonable to expect that this compound will receive attention as a potential material for display applications. This review article presents recent investigations into the application of 12CaO.7Al2O3 ceramic in various display devices, the challenges, opportunities and possible areas of future investigation into the development of this naturally abundant and environmental friendly material in the field of display.
Autors: Feizi, E.;Ray, A.K.;
Appeared in: Journal of Display Technology
Publication date: May 2016, volume: 12, issue:5, pages: 451 - 459
Publisher: IEEE
 
» 3-D Analytical Model of Helical Winding PM Machines Including Rotor Eddy Currents
Abstract:
Helical windings (or zigzag windings) are used in a number of applications, however, in electrical machines, mainly employed in low-power, high-speed permanent magnet (PM) brushless dc machines due to the cost effectiveness of the winding type while maintaining reasonable performance. Typically, helical windings are used for low-voltage applications due to their spiral form, which makes them most suitable for a small number of turns. In high-speed electrical machines, such a low number of turns are applicable. It is apparent that high-speed PM machines suffer from rotor eddy-current losses, which in some cases may lead to PM demagnetization due to overheating. The performance of the machine is compromised by these losses; hence, they have to be considered during the design procedure. There are many papers analyzing the magnetic field of these machines employing helical windings; however, none of them present a simple and precise electromagnetic model of a machine with the helical winding. This paper presents an analytical approach to model the resulting 3-D magnetic field of the helical winding, considering eddy currents in the conducting media of the rotor. The model is verified with the 3-D finite-element method by means of comparing magnetic field and rotor eddy-current losses.
Autors: Jumayev, S.;Paulides, J.J.H.;Boynov, K.O.;Pyrhonen, J.;Lomonova, E.A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2016, volume: 52, issue:5, pages: 1 - 8
Publisher: IEEE
 
» 3-D Lung Segmentation by Incremental Constrained Nonnegative Matrix Factorization
Abstract:
Accurate lung segmentation from large-size 3-D chest-computed tomography images is crucial for computer-assisted cancer diagnostics. To efficiently segment a 3-D lung, we extract voxel-wise features of spatial image contexts by unsupervised learning with a proposed incremental constrained nonnegative matrix factorization (ICNMF). The method applies smoothness constraints to learn the features, which are more robust to lung tissue inhomogeneities, and thus, help to better segment internal lung pathologies than the known state-of-the-art techniques. Compared to the latter, the ICNMF depends less on the domain expert knowledge and is more easily tuned due to only a few control parameters. Also, the proposed slice-wise incremental learning with due regard for interslice signal dependencies decreases the computational complexity of the NMF-based segmentation and is scalable to very large 3-D lung images. The method is quantitatively validated on simulated realistic lung phantoms that mimic different lung pathologies (seven datasets), in vivo datasets for 17 subjects, and 55 datasets from the Lobe and Lung Analysis 2011 (LOLA11) study. For the in vivo data, the accuracy of our segmentation w.r.t. the ground truth is 0.96 by the Dice similarity coefficient, 9.0 mm by the modified Hausdorff distance, and 0.87% by the absolute lung volume difference, which is significantly better than for the NMF-based segmentation. In spite of not being designed for lungs with severe pathologies and of no agreement between radiologists on the ground truth in such cases, the ICNMF with its total accuracy of 0.965 was ranked fifth among all others in the LOLA11. After excluding the nine too pathological cases from the LOLA11 dataset, the ICNMF accuracy increased to 0.986.
Autors: Hosseini-Asl, E.;Zurada, J.M.;Gimel farb, G.;El-Baz, A.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2016, volume: 63, issue:5, pages: 952 - 963
Publisher: IEEE
 
» 32-nm Multigate Si-nTFET With Microwave-Annealed Abrupt Junction
Abstract:
Microwave annealing (MWA) activates dopants through solid-phase epitaxial regrowth with low thermal budget. Optimizing the microwave power during MWA is capable of realizing low defect density at the junction, suppressing the dopant diffusion, and mitigating the straggle effect of ion implantation. These favorable features of MWA facilitate the formation of extremely abrupt junction profiles in tunnel FETs (TFETs). In conjunction with the improved gate-to-channel controllability of the multiple-gate (MG) structure, we demonstrate high-performance lateral n-type Si-TFETs using a CMOS-compatible process flow with excellent band-to-band tunneling efficiency and device scalability. The 32-nm MG Si-TFET shows promising characteristics, including a high ON-state current of 41.3 , a large current ON/OFF ratio of , and minimal short-channel effect using V and V.
Autors: Hou, F.-J.;Sung, P.-J.;Hsueh, F.-K.;Wu, C.-T.;Lee, Y.-J.;Chang, M.-N.;Li, Y.;Hou, T.-H.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2016, volume: 63, issue:5, pages: 1808 - 1813
Publisher: IEEE
 
» 3D Air-Touch User Interface With High Touch Accuracy on Stereoscopic Displays
Abstract:
To interact with stereoscopic images through 3D air-touch technology, the depth information for a touched 3D virtual object and the fingertip position should be aligned accurately. However, the fused 3D position is affected when the virtual object is blocked by the fingertip. Additionally, the 3D image with a large disparity decreases 3D touch accuracy. In order to improve the touch accuracy, virtual references and 3D image feedback were introduced respectively, and the touch accuracy was more than 90% based on a human interaction experiment.
Autors: Ting, C.;Jen, T.;Chen, C.;Huang, Y.;Shieh, H.D.;
Appeared in: Journal of Display Technology
Publication date: May 2016, volume: 12, issue:5, pages: 429 - 434
Publisher: IEEE
 
» 5E Mobile Inquiry Learning Approach for Enhancing Learning Motivation and Scientific Inquiry Ability of University Students
Abstract:
In recent years, many universities have opened courses to increase students' knowledge in the field of nanotechnology. These have been shown to increase students' knowledge of nanotechnology, but beyond this, advanced and applied nanotechnology courses should also focus on learning motivation and scientific enquiry abilities to equip students to develop the deeper knowledge and skills required for scientific application. This paper addresses this challenge. Due to the abstract nature of many nanotechnology concepts and in order to move from abstract knowledge to hands-on learning, an inquiry-based learning approach was adopted. Among the diverse inquiry-based learning models proposed, the 5E mobile inquiry-based approach, including the steps of engagement, exploration, explanation, elaboration, and evaluation, was considered most effective to enhance learners' understanding of nanotechnology. To evaluate the effectiveness of this proposed approach, a pretest–posttest quasi-experimental design was adopted with a total of 32 university students. Two sections of Nanotechnology Engineering, a general education course, were randomly assigned as either the comparison group (18 students; receiving lecture-based instruction, and using mobile devices) or the experimental group (14 students; receiving 5E inquiry learning, and using mobile devices). Mobile devices were adopted to enhance learners' experience, provide immediate access to information online, and provide enhanced hands-on learning. The empirical results demonstrate that the experimental condition, 5E mobile inquiry learning, had a positive impact on participants' learning motivation and scientific inquiry abilities.
Autors: Cheng, P.-H.;Yang, Y.-T.C.;Chang, S.-H.G.;Kuo, F.-R.R.;
Appeared in: IEEE Transactions on Education
Publication date: May 2016, volume: 59, issue:2, pages: 147 - 153
Publisher: IEEE
 
» Discretization for Sampled-Data Controller Synthesis via Piecewise Linear Approximation
Abstract:
This paper develops a new discretization method with piecewise linear approximation for the optimal controller synthesis problem of sampled-data systems, which is the problem of minimizing the -induced norm of sampled-data systems. We apply fast-lifting on the top of the lifting technique, by which the sampling interval is divided into subintervals with an equal width. The signals on each subinterval are then approximated by linear functions by introducing two types of ‘linearizing operators’ for input and output, which leads to piecewise linear approximation of sampled-data systems. By using the arguments of preadjoint operators, we provide an important inequality that forms a theoretical basis for tackling the optimal controller synthesis problem of sampled-data systems more efficiently than the conventional method. More precisely, a mathematical basis for the piecewise linear approximation method associated with the convergence rate is shown through this inequality, and this suggests that the piecewise linear approximation method may drastically outperform the conventional method in the optimal controller synthesis problem of sampled-data systems. We then provide a discretization procedure of sampled-data systems by which the optimal controller synthesis problem is converted to the discrete-time optimal controller synthe- is problem. Finally, effectiveness of the proposed method is demonstrated through a numerical example.
Autors: Kim, J.;Hagiwara, T.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2016, volume: 61, issue:5, pages: 1143 - 1157
Publisher: IEEE
 
» -Fair Power Allocation in Spectrum-Sharing Networks
Abstract:
To efficiently trade off system sum-rate and link fairness, this paper is dedicated to maximizing the sum of -fair utility in spectrum-sharing networks, where multiple interfering links share one channel. In the literature, three special cases, including (sum-rate maximization), (proportional fairness), and (max-min fairness), have been investigated; the complexity for cases and is still unknown. In this paper, we prove that the problem is convex when and is NP-hard when . To deal with the latter case, we transform the objective function and represent it by the difference of two concave functions (D.C.). Then, a power allocation algorithm is proposed with fast convergence to a local optimal point. Simulation results show that the proposed algorithm can obtain global optimality in two-link cases when . In addition, we can get a flexible tradeoff between sum-rate and fairness in terms of Jain's index by adjusting .
Autors: Guo, C.;Zhang, Y.;Sheng, M.;Wang, X.;Li, Y.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3771 - 3777
Publisher: IEEE
 
» -Problem-Based Transmission Rate Allocation With Packet Loss and Power Metrics Over Satellite Networks
Abstract:
This paper tackles the classical problem of transmission rate allocation in satellite networks where fading may negatively impact communications. Within the framework of multiobjective programming (MOP), this paper introduces a transmission rate allocation criterion among Earth stations (ESs) called -problem-based rate allocation . The allocations provided by are representative of a compromise among the need of different performance metrics such as packet loss and transmission power (TP). This paper determines the condition for the existence and the value of a transmission rate allocation bound , to which the transmission rate globally allocated by converges when the overall available transmission rate tends to infinity. The performance analysis, which is carried out through simulations under different satellite channel conditions, is aimed at investigating features, at showing the existence of the rate bound and the advantages concerning the rate allocation given by using , and at comparing with two other schemes in the literature concerning allocated rate, packet loss rate, transmit power, and execution time.
Autors: Bisio, I.;Delucchi, S.;Lavagetto, F.;Marchese, M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3312 - 3325
Publisher: IEEE
 
» Discretization for Sampled-Data Controller Synthesis via Piecewise Linear Approximation
Abstract:
This paper develops a new discretization method with piecewise linear approximation for the L1 optimal controller synthesis problem of sampled-data systems, which is the problem of minimizing the L-induced norm of sampled-data systems. We apply fast-lifting on the top of the lifting technique, by which the sampling interval [0, h) is divided into M subintervals with an equal width. The signals on each subinterval are then approximated by linear functions by introducing two types of `linearizing operators' for input and output, which leads to piecewise linear approximation of sampled-data systems. By using the arguments of preadjoint operators, we provide an important inequality that forms a theoretical basis for tackling the L1 optimal controller synthesis problem of sampled-data systems more efficiently than the conventional method. More precisely, a mathematical basis for the piecewise linear approximation method associated with the convergence rate is shown through this inequality, and this suggests that the piecewise linear approximation method may drastically outperform the conventional method in the L1 optimal controller synthesis problem of sampled-data systems. We then provide a discretization procedure of sampled-data systems by which the L1 optimal controller synthesis problem is converted to the discrete-time l1 optimal controller synthesis problem. Finally, effectiveness of the proposed method is demonstrated through a numerical example.
Autors: Kim, J.;Hagiwara, T.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2016, volume: 61, issue:5, pages: 1143 - 1157
Publisher: IEEE
 
» A 0.0054-mm2 Frequency-to-Current Conversion-Based Fractional Frequency Synthesizer in 32 nm Utilizing Deep Trench Capacitor
Abstract:
In this brief, a frequency-to-current conversion-based fractional frequency synthesizer is implemented in 32-nm technology utilizing a high-density deep trench capacitor. The technique proposed here can replace the use of multiple crystal oscillators or a phase-locked loop for medium accuracy clock generation with very low chip area and power consumption. In addition to exploiting the inherently low variation of capacitors as compared to that of transistors, the proposed circuit generates an output frequency proportional to the capacitor ratio, canceling out any small process-voltage-temperature (PVT) dependences of the capacitor. The performance of the fractional synthesizer is verified from chip measurement results. An output frequency range of 16–156 MHz is covered with a frequency resolution of 0.8 MHz using a 4-MHz reference clock. The total area of the frequency synthesizer core is only 0.0054 mm2, and it consumes 116 of power from a 0.9-V supply while generating an output frequency of 48 MHz. The output frequency variation is ±0.14% at 48 MHz for a temperature sweep from −40 °C to 90 °C. Periodic jitter measured from an on-chip high-resolution jitter measurement circuit is 115 ps (rms) at 76 MHz.
Autors: Kundu, S.;Kim, C.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 413 - 417
Publisher: IEEE
 
» A 0.1–3.5-GHz Duty-Cycle Measurement and Correction Technique in 130-nm CMOS
Abstract:
A duty-cycle correction technique using a novel pulsewidth modification cell is demonstrated across a frequency range of 100 MHz–3.5 GHz. The technique works at frequencies where most digital techniques implemented in the same technology node fail. An alternative method of making time domain measurements such as duty cycle and rise/fall times from the frequency domain data is introduced. The data are obtained from the equipment that has significantly lower bandwidth than required for measurements in the time domain. An algorithm for the same has been developed and experimentally verified. The correction circuit is implemented in a 0.13- CMOS technology and occupies an area of 0.011 mm2. It corrects to a residual error of less than 1%. The extent of correction is limited by the technology at higher frequencies.
Autors: Raja, I.;Banerjee, G.;Zeidan, M.A.;Abraham, J.A.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1975 - 1983
Publisher: IEEE
 
» A 12.5 mW, 11.1 , −115 dB THD, Settling, 18 bit SAR ADC Driver in 0.6 CMOS
Abstract:
A driver amplifier suitable for integration with an 18 bit 500 kS/s successive approximation register analog-to-digital converter (ADC) is reported. It accepts single-ended or fully differential inputs. The driver consumes 12.5 mW from a 5 V supply, has a −115 dB (−120 dB) total harmonic distortion for 8 Vppd output at 1 kHz (10 kHz), a 240 ns settling time to 0.01% accuracy for a 2 Vppd output step, and an input-referred noise of 11.1 . Simulated 18 bit settling time is 900 ns, and input-referred offset is 1.2 mV. This is one of the first reported 18 bit CMOS ADC driver amplifiers, and its performance is comparable to that of the state-of-the-art parts in other processes.
Autors: K.S., R.;Mitikiri, Y.;Krishnapura, N.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 443 - 447
Publisher: IEEE
 
» A 12.5 mW, 11.1 , −115 dB THD, Settling, 18 bit SAR ADC Driver in 0.6 CMOS
Abstract:
A driver amplifier suitable for integration with an 18 bit 500 kS/s successive approximation register analog-to-digital converter (ADC) is reported. It accepts single-ended or fully differential inputs. The driver consumes 12.5 mW from a 5 V supply, has a −115 dB (−120 dB) total harmonic distortion for 8 Vppd output at 1 kHz (10 kHz), a 240 ns settling time to 0.01% accuracy for a 2 Vppd output step, and an input-referred noise of 11.1 . Simulated 18 bit settling time is 900 ns, and input-referred offset is 1.2 mV. This is one of the first reported 18 bit CMOS ADC driver amplifiers, and its performance is comparable to that of the state-of-the-art parts in other processes.
Autors: K.S., R.;Mitikiri, Y.;Krishnapura, N.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 443 - 447
Publisher: IEEE
 
» A 260 MHz IF Sampling Bit-Stream Processing Digital Beamformer With an Integrated Array of Continuous-Time Band-Pass Modulators
Abstract:
We propose an ADC-digital codesign approach to IF sampling digital beamforming (DBF) that combines continuous-time bandpass modulators (CTBPDSMs) and bit-stream processing (BSP). This approach enables power- and area-efficient DBF by removing the need for digital multipliers and multiple decimators. The prototype beamformer digitizes eight 260 MHz IF signals at 1040 MS/s with eight CTBPDSMs, and performs digital down conversion and phase shifting with only multiplexers directly on the undecimated CTBPDSM outputs. With two sets of phase shifters, the prototype simultaneously forms two independent beams. Each phase shifter is controlled by a 12 bit programmable complex weight to provide a total of 240 phase-shift steps. By constructively combining inputs from eight elements, an 8.9 dB SNDR improvement is achieved, resulting in an array SNDR of 63.3 dB over a 10 MHz bandwidth. Fabricated in 65 nm CMOS, the eight-element two-beam prototype beamformer is the first IC implementation of IF sampling DBF. It occupies , and consumes 123.7 mW.
Autors: Jeong, J.;Collins, N.;Flynn, M.P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1168 - 1176
Publisher: IEEE
 
» A 3-D CPU-FPGA-DRAM Hybrid Architecture for Low-Power Computation
Abstract:
The power budget is expected to limit the portion of the chip that we can power ON at the upcoming technology nodes. This problem, known as the utilization wall or dark silicon, is becoming increasingly serious. With the introduction of 3-D integrated circuits (ICs), it is likely to become more severe. Thus, how to take advantage of the extra transistors, made available by Moore’s law and the onset of 3-D ICs, within the power budget poses a significant challenge to system designers. To address this challenge, we propose a 3-D hybrid architecture consisting of a CPU layer with multiple cores, a field-programmable gate array (FPGA) layer, and a DRAM layer. The architecture is designed for low power without sacrificing performance. The FPGA layer is capable of supporting a large number of accelerators. It is placed adjacent to the CPU layer, with a communication mechanism that allows it to access CPU data caches directly. This enables fast switches between these two layers. This architecture reduces the power and energy significantly, at better or similar performance. This then alleviates the dark silicon problem by letting us power ON more components to achieve higher performance. We evaluate the proposed architecture through a new framework we have developed. Relative to the out-of-order CPU, the accelerators on the FPGA layer can reduce function-level power by and energy-delay product (EDP) by , and application-level power by and EDP by , while delivering similar performance. For the entire system, this translates to a 47.5% power reduction relative to a baseline system that consists of a CPU layer and a DRAM layer- This also translates to a 72.9% power reduction relative to an alternative system that consists of a CPU layer, an L3 cache layer, and a DRAM layer.
Autors: Chen, X.;Jha, N.K.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1649 - 1662
Publisher: IEEE
 
» A 330- 400-MHz BPSK Transmitter in 0.18- CMOS for Biomedical Applications
Abstract:
An energy-efficient 400-MHz binary phase-shift keying (BPSK) transmitter (TX) is proposed for biomedical applications in this brief. The BPSK signal is generated by edge-combining multiple phases from a low-frequency voltage-controlled oscillator (VCO), which avoids power-hungry local oscillator generation at RF. Furthermore, the output matching network and edge combiner are merged into a power amplifier (PA), leading to a hardware-efficient and low-power design. Fabricated in a 0.18- CMOS process, the proposed TX consumes 330 and delivers −15-dBm output power. The modulator operates at 0.8 V, and PA operates at 0.2-V supply voltage. The TX can support a data rate up to 20 Mb/s, achieving an energy efficiency of 14.9 pJ/bit. The measured error vector magnitude at 20 Mb/s is 10%.
Autors: Tsai, Yi-Lin;Lin, Chun-Yu;Wang, Bang-Cyuan;Lin, Tsung-Hsien;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 448 - 452
Publisher: IEEE
 
» A 57-to-64-GHz 0.094-mm2 5-bit Passive Phase Shifter in 65-nm CMOS
Abstract:
This paper presents the design of a compact 60-GHz phase shifter that provides a 5-bit digital phase control and 360° phase range for beam-forming systems. The phase shifter is designed using the proposed cross-coupled bridged T-type topology and switched-varactor reflective-type topology. The topologies are analyzed using a small-signal equivalent circuit model. Furthermore, the design equations are derived and investigated. To validate the theoretical analysis, 60-GHz 5-bit 360° phase shifters are designed in a commercial 65-nm CMOS technology. The fabricated 360° phase shifter features good performance of 32 phase states from 57 to 64 GHz with an rms phase error of 4.4°, a total insertion loss of 14.3 ±2 dB, an rms gain error of 0.5 dB, of better than 9.5 dBm, and the power consumption of almost zero. To the best of our knowledge, the designed 360° phase shifter with the size of 0.094 mm2 is the smallest 5-bit passive phase shifter at frequencies around 60 GHz.
Autors: Meng, F.;Ma, K.;Yeo, K.S.;Xu, S.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1917 - 1925
Publisher: IEEE
 
» A 60 GHz CMOS Full-Duplex Transceiver and Link with Polarization-Based Antenna and RF Cancellation
Abstract:
This paper presents a fully integrated 60 GHz direct-conversion transceiver in 45 nm SOI CMOS for same-channel full-duplex (FD) wireless communication. FD operation is enabled by a novel polarization-based wideband reconfigurable self-interference cancellation (SIC) technique in the antenna domain. The antenna cancellation can be reconfigured from the IC to combat the variable SI scattering from the environment during in-field operation. A second RF cancellation path with gain control and phase control from the transmitter (TX) output to the LNA output further suppresses the residual SI to achieve the high levels of required SIC. With antenna and RF cancellation together, a total SI suppression of is achieved over a cancellation bandwidth of 1 GHz and can be maintained in the presence of nearby reflectors. In conjunction with digital SIC (DSIC) implemented in MATLAB, a FD link is demonstrated over 0.7 m with a signal-to-interference-noise-and-distortion ratio (SINDR) of 7.2 dB. To the best of our knowledge, this work achieves the highest integration level among FD transceivers irrespective of the operation frequency and demonstrates the first fully integrated mm-wave FD transceiver front-end and link.
Autors: Dinc, T.;Chakrabarti, A.;Krishnaswamy, H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1125 - 1140
Publisher: IEEE
 
» A 60-GHz Dual-Mode Distributed Active Transformer Power Amplifier in 65-nm CMOS
Abstract:
This paper presents a 60-GHz power amplifier (PA) fabricated in a 65-nm CMOS technology. The proposed PA utilizes a dual-mode amplification circuit topology to achieve a high level of output power and efficiency in a small die area. High-output power is achieved by combining class AB cascode stage with a conventional class A common source (CS) stage in a compact four-way differential distributed active transformer to increase the amplifier’s power density. Driver stages consist of an enhanced cascode stage followed by a CS stage to achieve a high power (HP) gain. Fabricated in a 65-nm CMOS process, the maximum measured gain of the 60-GHz PA is 22 dB within a wide 3-dB bandwidth of 14 GHz. A maximum saturated output power of 19.7 dBm is measured in HP mode while consuming 430 mW over a 1.2 V core supply. In low-power (LP) mode of operation, the power gain of 20 dB and 19.7 dBm saturated power is measured at 60 GHz. The proposed dual-mode topology achieves an HP added efficiency of 25% and 19% in HP and LP modes, respectively.
Autors: Farahabadi, P.M.;Moez, K.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1909 - 1916
Publisher: IEEE
 
» A Channel Assignment and Routing Algorithm for Energy Harvesting Multiradio Wireless Mesh Networks
Abstract:
Wireless mesh networks are being deployed all around the world both to provide ubiquitous connection to the Internet and to carry data generated by several services (video surveillance, smart grids, earthquake early warning systems, etc.). In those cases where fixed power connections are not available, mesh nodes operate by harvesting ambient energy (e.g., solar or wind power) and hence they can count on a limited and time-varying amount of power to accomplish their functions. Since we consider mesh nodes equipped with multiple radios, power savings and network performance can be maximized by properly routing flows, assigning channels to radios and identifying nodes/radios that can be turned off. Thus, the problem we address is a joint channel assignment and routing problem with additional constraints on the node power consumption, which is NP-complete. In this paper, we propose a heuristic, named minimum power channel assignment and routing algorithm (MP-CARA), which is guaranteed to return a local optimum for this problem. Based on a theoretical analysis that we present in the paper, which gives an upper bound on the outage probability as a function of the constraint on power consumption, we can guarantee that the probability that a node runs out of power with MP-CARA falls below a desired threshold. The performance of MP-CARA is assessed by means of an extensive simulation study aiming to compare the solutions returned by MP-CARA to those found by other heuristics proposed in the literature.
Autors: Avallone, S.;Banchs, A.;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: May 2016, volume: 34, issue:5, pages: 1463 - 1476
Publisher: IEEE
 
» A CLCL Resonant DC/DC Converter for Two-Stage LED Driver System
Abstract:
A CLCL resonant dc/dc converter has been proposed and analyzed in this paper for two-stage light-emitting diode (LED) drivers. The circuit performs zero-voltage-switching (ZVS) turn-on and quasi-zero-current-switching (ZCS) turn-off. Then, a two-stage system has been designed using a power factor correction circuit before the proposed converter. Optimum input impedance angle, dead time, and components parameters have been achieved after thoughtful design, thus obtaining good soft-switching performance and reduced voltage stress. A 100-W prototype has been realized and tested demonstrating its high feasibility and efficiency at full load and during dimming operations.
Autors: Wang, Y.;Guan, Y.;Xu, D.;Wang, W.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2883 - 2891
Publisher: IEEE
 
» A Cloud Gaming System Based on User-Level Virtualization and Its Resource Scheduling
Abstract:
Many believe the future of gaming lies in the cloud, namely Cloud Gaming, which renders an interactive gaming application in the cloud and streams the scenes as a video sequence to the player over Internet. This paper proposes GCloud, a GPU/CPU hybrid cluster for cloud gaming based on the user-level virtualization technology. Specially, we present a performance model to analyze the server-capacity and games’ resource-consumptions, which categorizes games into two types: CPU-critical and memory-io-critical. Consequently, several scheduling strategies have been proposed to improve the resource-utilization and compared with others. Simulation tests show that both of the First-Fit-like and the Best-Fit-like strategies outperform the other(s); especially they are near optimal in the batch processing mode. Other test results indicate that GCloud is efficient: An off-the-shelf PC can support five high-end video-games run at the same time. In addition, the average per-frame processing delay is 8∼19 ms under different image-resolutions, which outperforms other similar solutions.
Autors: Zhang, Y.;Qu, P.;Zheng, W.;Cihang, J.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2016, volume: 27, issue:5, pages: 1239 - 1252
Publisher: IEEE
 
» A CNN Regression Approach for Real-Time 2D/3D Registration
Abstract:
In this paper, we present a Convolutional Neural Network (CNN) regression approach to address the two major limitations of existing intensity-based 2-D/3-D registration technology: 1) slow computation and 2) small capture range. Different from optimization-based methods, which iteratively optimize the transformation parameters over a scalar-valued metric function representing the quality of the registration, the proposed method exploits the information embedded in the appearances of the digitally reconstructed radiograph and X-ray images, and employs CNN regressors to directly estimate the transformation parameters. An automatic feature extraction step is introduced to calculate 3-D pose-indexed features that are sensitive to the variables to be regressed while robust to other factors. The CNN regressors are then trained for local zones and applied in a hierarchical manner to break down the complex regression task into multiple simpler sub-tasks that can be learned separately. Weight sharing is furthermore employed in the CNN regression model to reduce the memory footprint. The proposed approach has been quantitatively evaluated on 3 potential clinical applications, demonstrating its significant advantage in providing highly accurate real-time 2-D/3-D registration with a significantly enlarged capture range when compared to intensity-based methods.
Autors: Miao, S.;Wang, Z.;Liao, R.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: May 2016, volume: 35, issue:5, pages: 1352 - 1363
Publisher: IEEE
 
» A Common Grounded Z-Source DC–DC Converter With High Voltage Gain
Abstract:
In this paper, a common grounded Z-source dc-dc converter with high voltage gain is proposed for photovoltaic (PV) applications, which require a relatively high output-input voltage conversion ratio. Compared with the traditional Z-source dc-dc converter, the proposed converter, which employs a conventional Z-source network, can obtain higher voltage gain and provide the common ground for the input and output without any additional components, which results in low cost and small size. Moreover, the proposed converter features low voltage stresses of the switch and diodes. Therefore, the efficiency and reliability of the proposed converter can be improved. The operating principle, parameters design, and comparison with other converters are analyzed. Simulation and experimental results are given to verify the aforementioned characteristics and theoretical analysis of the proposed converter.
Autors: Shen, H.;Zhang, B.;Qiu, D.;Zhou, L.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2925 - 2935
Publisher: IEEE
 
» A Comparison of Small-Area Population Estimation Techniques Using Built-Area and Height Data, Riyadh, Saudi Arabia
Abstract:
Small-area population estimation is important for many applications. This paper explores the usefulness of Landsat data, remotely sensed height data, census population, and dwelling unit data to provide small-area population estimates. Riyadh, Saudi Arabia was selected as a suitable area to test a set of methods for population downscaling. Two broad approaches were applied: 1) statistical modeling and 2) areal interpolation. With regard to statistical modeling, regression through the origin was used to model the relationship between density of dwelling units and built area proportion at the block level and the coefficients were used to downscale the density of dwelling units to the parcel level. Areal interpolation with ancillary data (dasymetric mapping) used the block and parcel levels as the source and target zones, respectively. The population distribution was then estimated based on the average population per dwelling unit. Eight models were developed and tested. A conventional regression model, using only built area as a covariate, was used as a benchmark and compared with the more sophisticated models. Remotely sensed height data were used to: 1) create number of floors; 2) classify the built area into different categories; and 3) increase the user’s accuracy of the built area. It was found that remotely sensed height data were useful to explain the variation in the dependent variable across the selected study area. Dasymetric mapping was applied in order to provide a comparison, while acknowledging that the method uses population data not available in the regression approach.
Autors: Alahmadi, M.;Atkinson, P.;Martin, D.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2016, volume: 9, issue:5, pages: 1959 - 1969
Publisher: IEEE
 
» A Composite Strategy for Power Oscillation Damping Control Using Local and Wide Area Feedback Signals
Abstract:
Non-local measurements from wide area measurement systems can be used to synthesize feedback signals for FACTS or HVDC based power oscillation damping controllers. Although non-local feedback signals may have better damping influence than local feedback signals, they involve greater complexity and reduced robustness due to the possibility of partial or complete loss of communication. A composite control strategy is proposed in this paper, which uses both local and non-local feedback channels to achieve enhanced damping and improved robustness. Special local signals and their non-local equivalents are identified for series reactive and shunt real power injection devices, which facilitate the design of controllers with a simple structure and fewer parameters. Unlike modal speed signals, synthesis of these signals does not require an online eigen-solution. Case studies are presented which demonstrate the efficacy and robustness of this strategy.
Autors: Pradhan, V.;Kulkarni, A.M.;Khaparde, S.A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2348 - 2360
Publisher: IEEE
 
» A Computer-Assistance Learning System for Emotional Wording
Abstract:
Language learners' limited lexical knowledge leads to imprecise wording. This is especially true when they attempt to express their emotions. Many learners rely heavily on the traditional thesaurus. Unfortunately, this fails to provide appropriate suggestions for lexical choices. To better aid English-as-a-second-language learners with word choices, we propose RESOLVE, which provides ranked synonyms of emotion words based on contextual information. RESOLVE suggests precise emotion words regarding the events in the relevant context. Patterns are learned to capture emotion events, and various factors are considered in the scoring function for ranking emotion words. We also describe an online writing system developed using RESOLVE and evaluate its effectiveness for learning assistance with a writing task. Experimental results showed that RESOLVE yielded a superior performance on NDCG@5 which significantly outperformed both PMI and SVM approaches, and offered better suggestions than Roget's Thesaurus and PIGAI (an online automated essay scoring system). Moreover, when applying it to the writing task, students' appropriateness with emotion words was 30 percent improved. Less-proficient learners benefited more from RESOLVE than highly-proficient learners. Post-tests also showed that after using RESOLVE, less-proficient learners' ability to use emotion words approached that of highly-proficient learners. RESOLVE thus enables learners to use precise emotion words.
Autors: Chen, Wei-Fan;Chen, Mei-Hua;Chen, Ming-Lung;Ku, Lun-Wei;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2016, volume: 28, issue:5, pages: 1093 - 1104
Publisher: IEEE
 
» A Contract-Ruled Economic Model for QoS Guarantee in Mobile Peer-to-Peer Streaming Services
Abstract:
Current commercial mobile streaming applications call for innovative technologies for stable QoS guarantee. In this paper, we provide a comprehensive treatment of QoS guarantee through a contract-ruled approach. In particular, we envision a peer-assisted mobile peer-to-peer streaming system as a QoS trading market, where all parties involved in the system, i.e., Service Provider (SP), End User (EU), and Assisting Peers (APs), are real economic entities that are organized with contractual constraints to achieve a stable and guaranteed QoS output. The QoS trading in the market is divided into two parts. One is a basic contract that establishes the business agreement between an interested EU and a SP. We propose a QoS contingent payment to mitigate the EU's concern on the uncertainty of QoS delivery and derive an optimal contract that achieves Pareto efficiency. The other is a subcontract, in which we model transactions between the SP and contracted peers as a principal multi-agents problem, that achieves a desired joint QoS output. We further design a sharing scheme with team penalty that could overcome the free-riding problem existed in the subcontract and show that the Pareto efficiency can be achieved by setting a proper team penalty. Both numerical evaluations and prototype experiments demonstrate the effectiveness of our proposed scheme.
Autors: Yang, L.;Lou, W.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: May 2016, volume: 15, issue:5, pages: 1047 - 1061
Publisher: IEEE
 
» A Correlation-Based Framework for Evaluating Postural Control Stochastic Dynamics
Abstract:
The inability to maintain balance during varying postural control conditions can lead to falls, a significant cause of mortality and serious injury among older adults. However, our understanding of the underlying dynamical and stochastic processes in human postural control have not been fully explored. To further our understanding of the underlying dynamical processes, we examine a novel conceptual framework for studying human postural control using the center of pressure (COP) velocity autocorrelation function (COP-VAF) and compare its results to Stabilogram Diffusion Analysis (SDA). Eleven healthy young participants were studied under quiet unipedal or bipedal standing conditions with eyes either opened or closed. COP trajectories were analyzed using both the traditional posturographic measure SDA and the proposed COP-VAF. It is shown that the COP-VAF leads to repeatable, physiologically meaningful measures that distinguish postural control differences in unipedal versus bipedal stance trials with and without vision in healthy individuals. More specifically, both a unipedal stance and lack of visual feedback increased initial values of the COP-VAF, magnitude of the first minimum, and diffusion coefficient, particularly in contrast to bipedal stance trials with open eyes. Use of a stochastic postural control model, based on an Ornstein-Uhlenbeck process that accounts for natural weight-shifts, suggests an increase in spring constant and decreased damping coefficient when fitted to experimental data. This work suggests that we can further extend our understanding of the underlying mechanisms behind postural control in quiet stance under varying stance conditions using the COP-VAF and provides a tool for quantifying future neurorehabilitative interventions.
Autors: Hernandez, M.E.;Snider, J.;Stevenson, C.;Cauwenberghs, G.;Poizner, H.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: May 2016, volume: 24, issue:5, pages: 551 - 561
Publisher: IEEE
 
» A Digitally Intensive Transmitter/PA Using RF-PWM With Carrier Switching in 130 nm CMOS
Abstract:
A digitally intensive transmitter using RF pulse-width-modulation (PWM) with a class-D power amplifier (PA) is described. The use of carrier switching for alleviating the dynamic range limitation that can be observed in classical RF-PWM implementations is introduced. The approach employs full carrier frequency for half of the amplitude range and the second harmonic of half of the carrier frequency, for the remainder of the amplitude range. This concept not only allows the transmitter to drive modulated signals with large peak-to-average power ratios (PAPR) but also improves back-off efficiency due to reduced switching losses in the half carrier-frequency mode. A glitch-free phase selector is proposed that removes the deleterious glitches that can occur at the input data transitions. The phase-selector also prevents D flip-flop setup-and-hold time violations. The transmitter has been implemented in a 130-nm CMOS process. The measured peak output power and power-added-efficiency (PAE) are 25.6 dBm and 34%, respectively. While driving 802.11g 20 MHz 64-QAM OFDM signals, the average output power is 18.3 dBm and the PAE is 16% with an EVM of .
Autors: Cho, K.;Gharpurey, R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1188 - 1199
Publisher: IEEE
 
» A Distributed and Privacy-Aware Speed Advisory System for Optimizing Conventional and Electric Vehicle Networks
Abstract:
One of the key ideas to make intelligent transportation systems work effectively is to deploy advanced communication and cooperative control technologies among vehicles and road infrastructures. In this spirit, we propose a consensus-based distributed speed advisory system that optimally determines a recommended common speed for a given area in order that the group emissions, or group battery consumptions, are minimized. Our algorithms achieve this in a privacy-aware manner; that is, individual vehicles do not reveal in-vehicle information to other vehicles or to infrastructure. A mobility simulator is used to illustrate the efficacy of the algorithm, and hardware-in-the-loop tests involving a real vehicle are given to illustrate user acceptability and ease of deployment.
Autors: Liu, M.;Ordonez-Hurtado, R.H.;Wirth, F.;Gu, Y.;Crisostomi, E.;Shorten, R.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: May 2016, volume: 17, issue:5, pages: 1308 - 1318
Publisher: IEEE
 
» A Dynamic Coherency Identification Method Based on Frequency Deviation Signals
Abstract:
This paper presents a new method to dynamically determine coherent generators and electrical areas of an interconnected power system. The proposed method is based on dynamic frequency deviations of both generator and non-generator buses, with respect to the system nominal frequency. The proposed method 1) largely overcomes the limitations of the existing model-based and measurement-based coherency identification methods, 2) enables dynamic tracking of the coherency time-evolution, and 3) provides noise immunity which is imperative in practical implementation. The method also promises the potential for real-time coherency calculation. The proposed method is applied to the 16-machine/68-bus NPCC system based on time-domain simulation studies in the PSS/E platform and the results are compared with those of the classical slow-coherency (model-based) method and a measurement-based method.
Autors: Khalil, A.M.;Iravani, R.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 1779 - 1787
Publisher: IEEE
 
» A Dynamic Graph-Based Scheduling and Interference Coordination Approach in Heterogeneous Cellular Networks
Abstract:
To meet the demand of increasing mobile data traffic and provide better user experience, heterogeneous cellular networks (HCNs) have become a promising solution to improve both the system capacity and coverage. However, due to dense self-deployment of small cells in a limited area, serious interference from nearby base stations may occur, which results in severe performance degradation. To mitigate downlink interference and utilize spectrum resources more efficiently, we present a novel graph-based resource allocation and interference management approach in this paper. First, we divide small cells into cell clusters, considering their neighborhood relationships in the scenario. Then, we develop another graph clustering scheme to group user equipment (UE) in each cell cluster into UE clusters with minimum intracluster interference. Finally, we utilize a proportional fairness scheduling scheme to assign subchannels to each UE cluster and allocate power using water-filling method. To show the efficacy and effectiveness of our proposed approach, we propose a dual-based approach to search for optimal solutions as the baseline for comparisons. Furthermore, we compare the graph-based approach with the state of the art and a distributed approach without interference coordination. The simulation results show that our graph-based approach reaches more than 90% of the optimal performance and achieves a significant improvement in spectral efficiency compared with the state of the art and the distributed approach both under cochannel and orthogonal deployments. Moreover, the proposed graph-based approach has low computation complexity, making it feasible for real-time implementation.
Autors: zhou, l.;Hu, X.;Ngai, E.;Zhao, H.;Wang, S.;Wei, J.;Leung, V.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3735 - 3748
Publisher: IEEE
 
» A Dynamically Biased Multiband 2G/3G/4G Cellular Transmitter in 28 nm CMOS
Abstract:
We present a highly configurable, low-power, low-area, low-EVM, SAW-less transmitter (TX) architecture that is based on a dynamically biased power mixer. All FDD/TDD bands from 0.7 to 2.7 GHz for 4G LTE Rel-11 and 3G are supported in addition to 2G quad bands. The power-mixer bias current is dynamically adjusted based on the instantaneous baseband signal swing using a fully-differential hybrid full-wave rectifier/envelope-detector circuit. Dynamic biasing leads to greater than 50% current savings when compared to fixed-biasing while providing a higher output power with better linearity. Implemented in 28 nm CMOS technology, the TX shows better than RX-band noise emission and ACLR for output powers up-to across all 3G/4G bands, while demonstrating above 80 dB of gain control range. In addition, the TX can be configured to provide better than CIM3, allowing it to meet stringent spurious emission specifications when transmitting 1 RB 4G LTE signals in B13/B26/B1.
Autors: Seth, S.;Kwon, D.H.;Venugopalan, S.;Son, S.W.;Zuo, Y.;Bhagavatula, V.;Lim, J.;Oh, D.;Cho, T.B.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1096 - 1108
Publisher: IEEE
 
» A Fast LP Approach for Enhanced Utilization of Variable Impedance Based FACTS Devices
Abstract:
Transmission systems are under stress and need to be upgraded. Better utilization of the existing grid provides a fast and cheap alternative to building new transmission. One way to improve the utilization of the transmission network is power flow control via flexible ac transmission system (FACTS) devices. While FACTS devices are used today, the utilization of these devices is limited; traditional dispatch models (e.g., security constrained economic dispatch) assume a fixed, static transmission grid even though it is rather flexible. The primary barrier is the complexity that is added to the power flow problem. The mathematical representation of the DC optimal power flow, with the added modeling of FACTS devices, is a nonlinear program (NLP). This paper presents a method to convert this NLP into a mixed-integer linear program (MILP). The MILP is reformulated as a two-stage linear program, which enforces the same sign for the voltage angle differences for the lines equipped with FACTS. While this approximation does not guarantee optimality, more than 98% of the presented empirical results, based on the IEEE 118-bus and Polish systems, achieved global optimality. In the case of suboptimal solutions, the savings were still significant and the solution time was dramatically reduced.
Autors: Sahraei-Ardakani, M.;Hedman, K.W.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2204 - 2213
Publisher: IEEE
 
» A Flywheel Energy Storage System for Fault Ride Through Support of Grid-Connected VSC HVDC-Based Offshore Wind Farms
Abstract:
Voltage source converter (VSC)-based high voltage DC (HVDC) transmission is considered the future of offshore power transmission. This paper aims at providing a reliable VSC-HVDC transmission system architecture between offshore wind farms and onshore grids. In this paper, a large-capacity, low-speed flywheel energy storage system (FESS) based on a squirrel cage induction machine is applied in parallel with the VSC-HVDC at the grid side converter. The FESS is dedicated for surge power (due to power flow imbalance during fault) absorption instead of being dissipated in the form of resistive losses. Since the duration of these surges is relatively small, it has been shown that the flywheel can effectively mitigate this problem. In addition to the fault ride-through support during fault conditions, the FESS is employed for power leveling functionality during normal operation. The performance parameters of the proposed approach are investigated via both simulation and experimental results. A 132-kV, 100-MW HVDC system is simulated using MATLAB/Simulink during normal and fault conditions. The proposed architecture is substantiated experimentally through a scaled down test rig with a 2-kW FESS.
Autors: Daoud, M.I.;Massoud, A.M.;Abdel-Khalik, A.S.;Elserougi, A.;Ahmed, S.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 1671 - 1680
Publisher: IEEE
 
» A Formal Approach to Power Optimization in CPSs With Delay-Workload Dependence Awareness
Abstract:
The design of cyber-physical systems (CPSs) faces various new challenges that are unheard of in the design of classical real-time systems. Power optimization is one of the major design goals that is witnessing such new challenges. The presence of interaction between the cyber and physical components of a CPS leads to dependence between the time delay of a computational task and the amount of workload in the next iteration. We demonstrate that it is essential to take this delay-workload dependence into consideration in order to achieve low power consumption. In this paper, we identify this new challenge, and present the first formal and comprehensive model to enable rigorous investigations on this topic. We propose a simple power management policy, and show that this policy achieves a best possible notion of optimality. In fact, we show that the optimal power consumption is attained in a “steady-state” operation and a simple policy of finding and entering this steady state suffices, which can be quite surprising considering the added complexity of this problem. Finally, we validated the efficiency of our policy with experiments.
Autors: An, H.;Yang, H.;Ha, S.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: May 2016, volume: 35, issue:5, pages: 750 - 763
Publisher: IEEE
 
» A Framework-Based Approach to Utility Big Data Analytics
Abstract:
As advances in scientific and business data collection have exponentially created more data, electric utility companies are seeking new tools and techniques to turn the collected data into operational insights and assist with cost-saving decisions. The cost of building a specific business-driven big data application, however, can be tremendously high. This paper proposes developing a standard-based software framework to address key utility big data issues and foster development of big data analytical applications. Based on the support of this generic framework, new big data analytical solutions can be rapidly built and deployed to improve business practices in a utility organization. The proposed framework-based approach, as demonstrated in the conducted case studies, has proven to be promising for addressing the emerging big data challenges in the utility industry.
Autors: Zhu, J.;Zhuang, E.;Fu, J.;Baranowski, J.;Ford, A.;Shen, J.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2455 - 2462
Publisher: IEEE
 
» A Game Theory Inspired Approach to Stable Core Decomposition on Weighted Networks
Abstract:
Meso-scale structural analysis, like core decomposition has uncovered groups of nodes that play important roles in the underlying complex systems. The existing core decomposition approaches generally focus on node properties like degree and strength. The node centric approaches can only capture a limited information about the local neighborhood topology. In the present work, we propose a group density based core analysis approach that overcome the drawbacks of the node centric approaches. The proposed algorithmic approach focuses on weight density, cohesiveness, and stability of a substructure. The method also assigns an unique score to every node that rank the nodes based on their degree of core-ness. To determine the correctness of the proposed method, we propose a synthetic benchmark with planted core structure. A performance test on the null model is carried out using a weighted lattice without core structures. We further test the stability of the approach against random noise. The experimental results prove the superiority of our algorithm over the state-of-the-arts. We finally analyze the core structures of several popular weighted network models and real life weighted networks. The experimental results reveal important node ranking and hierarchical organization of the complex networks, which give us better insight about the underlying systems.
Autors: Basu, S.;Maulik, U.;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2016, volume: 28, issue:5, pages: 1105 - 1117
Publisher: IEEE
 
» A General Active Capacitor Voltage Regulating Method for L-Level M-Cell N-Phase Flying Capacitor Multilevel Inverter With Arbitrary DC Voltage Distribution
Abstract:
The flying capacitor multilevel inverter (FCMLI) is one of the well-known structures of multilevel inverters having attracted considerable attention because of its merits. In spite of its many advantages, it has some limitations such as high volume and complicated control method because of its bulky capacitors and their voltage balancing requirement. Moreover, the high number of power semiconductors required makes this structure susceptible to failure. To increase the ratio of the number of levels to the number of components, an uneven distribution of capacitor voltages has been suggested in previous reports; however, this approach complicates the control method. Up to now, almost all presented methods suffer from high computational load and/or structure-dependent algorithm. In this paper, a simple state-based and structure-independent method is proposed for capacitor voltage regulation. The proposed method is straightforward and can perform online computation of switching sequences in a computationally efficient manner without any need for stored information or look-up tables. The method is conveniently extendible to any number of cells and levels in an FCMLI structure with arbitrary dc link voltage distribution schemes. Simulation and experimental results show the effectiveness and simplicity of this method.
Autors: Amini, J.;Viki, A.H.;Radan, A.;Moallem, M.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2659 - 2668
Publisher: IEEE
 
» A Generalized Approach for Computing Most Sensitive Eigenvalues With Respect to System Parameter Changes in Large-Scale Power Systems
Abstract:
The recently-developed Two-sided Arnoldi and Sensitive Pole Algorithm (TSA-SPA) is effective and robust in computing the most sensitive eigenvalues with respect to control parameter changes in large-scale power systems. This paper extends the TSA-SPA to handle different system parameters, including control, system operating and network parameters. The proposed algorithm makes use of perturbation in reduced matrix obtained from Arnoldi/TSA method through linearization and successfully avoids the need for TSA-SPA to formulate the whole state matrix of the system and to explicitly calculate the elements' variations in system state matrix. A new deflation method is also proposed and adopted in the generalized algorithm to find other sensitive eigenvalues. Simulation results illustrate that the generalized algorithm is able to not only maintain the excellent properties of TSA-SPA in terms of convergence and robustness, but also consider various parameter changes effectively in large-scale power systems.
Autors: Chung, C.Y.;Dai, B.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2278 - 2288
Publisher: IEEE
 
» A Graph Laplacian Approach to Coordinate-Free Formation Stabilization for Directed Networks
Abstract:
This paper concentrates on coordinate-free formation control for directed networks, for which the dynamic motion of each agent is assumed to be governed only by a local control. We develop a graph Laplacian approach to solve the global and exponential formation stablization problem using merely relative position measurements between neighbors. First, to capture the sensing and control architectures that are needed to maintain the shape of a formation, a necessary and sufficient topological condition is proposed. Second, a Laplacian-based control law is developed for the stablization problem of a group of mobile agents to a desired formation shape under both fixed and switching topologies due to temporal node failures. Simulation results are provided to demonstrate that our Laplacian-based formation control strategy is inherently fault-tolerant and robust to node failures.
Autors: Lin, Z.;Wang, L.;Han, Z.;Fu, M.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2016, volume: 61, issue:5, pages: 1269 - 1280
Publisher: IEEE
 
» A High-Gain Broadband Gradient Refractive Index Metasurface Lens Antenna
Abstract:
The design, simulation, and measurement results of a high-gain broadband gradient refractive index (GRIN) planar lens fed by an antipodal exponential taper slot antenna (ATSA) are presented. As a constituent part of this lens, a novel nonresonant metamaterial unit cell, composed of bilayer triple rectangular rings, is proposed and its equivalent circuit model is developed and described. It is shown that, by utilizing this element, stronger capacitive couplings between adjacent metallic layers are realized resulting in a large refractive index variation of about 2.5, and hence, a thin lens with a thickness of , where is the wavelength at 9.5 GHz. In addition, since the unit cell is designed to resonate at higher frequencies, its refractive index response is smoothly increased over a broad frequency range and this considerably enhances the operating bandwidth of the lens. The achieved measured results demonstrate a broad matching and gain bandwidths of 52% (7–12 GHz) and 65% (7–13.2 GHz), respectively. Furthermore, this lens offers a high aperture efficiency of 50% (21.2 dB gain) at the center frequency, and its sidelobe and cross-polarization levels are less than and across the entire matched band, respectively.
Autors: Erfani, E.;Niroo-Jazi, M.;Tatu, S.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2016, volume: 64, issue:5, pages: 1968 - 1973
Publisher: IEEE
 
» A High-Voltage (>600 V) N-Island LDMOS With Step-Doped Drift Region in Partial SOI Technology
Abstract:
A high-voltage lateral double-diffused MOSFET with N-island (NIS) and step-doped drift (SDD) region in partial silicon-on-insulator (PSOI) technology is proposed. In the lateral direction, the SDD region and the NIS on the buried oxide layer (BOX) introduce two additional electric field peaks, which can improve the surface field distribution and breakdown voltage (BV). In the vertical direction, due to the highly doped NIS, a higher electric field is induced into the BOX layer, which can achieve a higher vertical BV. As a consequence, the BV is enhanced significantly. Moreover, the NIS with a larger doping concentration can provide a higher current of the proposed device, and thus, the ON-resistance ( is reduced. The 2-D simulation results show that the BV of the proposed structure can achieve 680 V, and is reduced by 10.2% and 14.7% in comparison with the conventional PSOI and buried n-type layer PSOI, respectively.
Autors: Hu, Y.;Wang, H.;Du, C.;Ma, M.;Chan, M.;He, J.;Wang, G.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2016, volume: 63, issue:5, pages: 1969 - 1976
Publisher: IEEE
 
» A Hybrid Feature Selection Scheme for Reducing Diagnostic Performance Deterioration Caused by Outliers in Data-Driven Diagnostics
Abstract:
In practice, outliers, defined as data points that are distant from the other agglomerated data points in the same class, can seriously degrade diagnostic performance. To reduce diagnostic performance deterioration caused by outliers in data-driven diagnostics, an outlier-insensitive hybrid feature selection (OIHFS) methodology is developed to assess feature subset quality. In addition, a new feature evaluation metric is created as the ratio of the intraclass compactness to the interclass separability estimated by understanding the relationship between data points and outliers. The efficacy of the developed methodology is verified with a fault diagnosis application by identifying defect-free and defective rolling element bearings under various conditions.
Autors: Kang, M.;Islam, M.R.;Kim, J.;Kim, J.;Pecht, M.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 3299 - 3310
Publisher: IEEE
 
» A Leakage Compensation Design for Low Supply Voltage SRAM
Abstract:
A leakage current compensation design for nanoscale SRAMs is proposed in this paper. The proposed compensation design is composed of a leakage current sensor, which generates a warning signal if the leakage is over a predefined threshold, and a compensation circuit following the sensor, which will be activated to speed up the read operation. At 0.6 V system voltage, the proposed compensation design reduces 27.86% of the average power dissipation, and 54.88% of the read delay at the expense of 3.64% area overhead. The proposed Static Random-Access Memory is implemented using the TSMC 40-nm CMOS logic technology. The energy per access is measured to be 0.9411 pJ given a 600-mV power supply and a 54-MHz system clock rate.
Autors: Wang, C.-C.;Wang, D.-S.;Liao, C.-H.;Chen, S.-Y.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1761 - 1769
Publisher: IEEE
 
» A Linear Program for System-Level Control of Regional PHEV Charging Stations
Abstract:
This paper studies dynamic control of a system of plug-in hybrid electric vehicle (PHEV) charging stations. A finite horizon stochastic program is presented. Based upon the 15-min updated period of the electricity market price, the objective function is to maximize profit, which is the revenue benefit from selling back to the grid and the charging of the vehicles minus the cost of buying electricity from the grid. The state variables in each 15-min time period consist of the total wind purchased from the system, solar power generation at each charging station, total demand at each station, and nodal market price at stations’ location. A stochastic program is formulated, and the mean value problem as a deterministic linear program is solved. Potential strategies are presented to provide insight into the behavior of the system.
Autors: Kulvanitchaiyanunt, A.;Sarikprueck, P.;Lee, W.-J.;Rosenberger, J.;Chen, V.C.P.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2046 - 2052
Publisher: IEEE
 
» A Linear Quadratic Regulator-Based Optimal Direct Thrust Force Control of Linear Permanent-Magnet Synchronous Motor
Abstract:
Linear permanent-magnet machines are often characterized by low inductance and short pole-pitch which leads to a small operational range of load angles. The resultant control performance using conventional direct thrust force control (DTFC) techniques is poor with high force ripple. This research improves this aspect of DTFC. A novel multiple-input multiple-output (MIMO) state-space model, independent of the mover's speed, having stator flux and thrust force as states, is formulated for the linear permanent-magnet synchronous motor (PMSM). An optimal linear state feedback control scheme is then designed using the optimal linear quadratic regulator technique. Integral action is added to the designed control scheme by state augmentation to minimize the steady-state error and reduce the force ripple. Experimental results clearly prove that the proposed optimal control scheme results in a faster transient response of speed and force with improved steady-state regulation of force and flux when compared to the state of the art.
Autors: Cheema, M.A.M.;Fletcher, J.E.;Xiao, D.;Rahman, M.F.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2722 - 2733
Publisher: IEEE
 
» A Low-Cost Accelerometer Developed by Inkjet Printing Technology
Abstract:
In this paper, an inkjet-printed sensor in the mesoscale is presented with the aim to investigate its behavior as an accelerometer in the low-frequency domain (up to 20 Hz), which properly fits with the need of typical applications in the field of human and seismic monitoring. The accelerometer consists of a Polyethylene terephthalate membrane clamped by four spring legs to a fixed support. The sensing readout strategy is implemented through four strain gauges directly printed onto the flexible substrate. The advantages of the approach proposed are mainly related to the adopted low-cost direct printing technology, which allows for the realization of cheap and customizable devices. The sensor behavior has been deeply investigated. The device responsivity and resolution are 9.4 mV/g and 0.126 g, respectively, at 10 Hz, and 41.0 mV/g and 0.003 g, respectively, at 35 Hz. The performances obtained encourage the development of the all-inkjet-printed sensor proposed, especially taking into account its low cost and disposable features.
Autors: Ando, B.;Baglio, S.;Lombardo, C.O.;Marletta, V.;Pistorio, A.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2016, volume: 65, issue:5, pages: 1242 - 1248
Publisher: IEEE
 
» A Low-Cost, Radiation-Hardened Method for Pipeline Protection in Microprocessors
Abstract:
The aggressive scaling of semiconductor technology has significantly increased the radiation-induced soft-error rate in modern microprocessors. Meanwhile, due to the increasing complexity of modern processor pipelines and the limited error-tolerance capabilities that previous radiation hardening techniques can provide, the existing pipeline protection mechanisms cannot achieve complete protection. This paper proposes a complete and cost-effective pipeline protection mechanism using a self-checking architecture. The radiation-hardened pipeline is achieved by incorporating soft-error- and timing-error-tolerant flip-flop (SETTOFF)-based self-checking cells into the sequential cells of the pipeline. A replay recovery mechanism is also developed at the architectural level to recover the detected errors. The proposed pipeline protection technique is implemented in an OpenRISC microprocessor in a 65-nm technology. A gate-level transient fault-injection and analysis technique is used to evaluate the error-tolerance capability of the proposed hardened pipeline design. The results show that compared with the techniques such as triple modular redundancy, the SETTOFF-based self-checking technique requires over 30% less area and 80% less power overheads. Meanwhile, the error-tolerant and self-checking capabilities of the register allow the proposed pipeline protection technique to provide a noticeably higher level of reliability for different parts of the pipeline compared with the previous pipeline protection techniques.
Autors: Lin, Y.;Zwolinski, M.;Halak, B.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1688 - 1701
Publisher: IEEE
 
» A Low-Jitter Fast-Locked All-Digital Phase-Locked Loop With Phase–Frequency-Error Compensation
Abstract:
The previous fast-locked all-digital phase-locked loop (ADPLL) usually suffers from large timing jitter due to the steep frequency transfer curve of its digitally controlled oscillator (DCO). This paper presents an ADPLL that possesses a coarse frequency selection function. All DCO frequency transfer curves of the ADPLL have gentle slopes. The ADPLL selects one transfer curve before acquisition. To fulfill the fast-acquisition requirement, the proposed ADPLL employs the phase–frequency-error compensation technique. In the acquisition mode, the phase-error compensator resolves the problem of phase-error accumulation. Meanwhile, the frequency-error compensator predicts a proper control code by calculating the cycle time difference between the reference clock and the derived signal fed back from the DCO. Therefore, the proposed ADPLL can compensate for the phase and the frequency errors simultaneously. The experimental results show that the proposed ADPLL possesses a fine-tuning acquisition within 5 reference clock cycles. After acquisition, the code updates in a fractional manner in the tracking mode to enhance the tracking jitter performance. The ADPLL output frequency ranges from 860 MHz to 1 GHz. The measured rms jitter is 1.31 ps at 1-GHz frequency.
Autors: Ho, Y.-H.;Yao, C.-Y.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1984 - 1992
Publisher: IEEE
 
» A Method for Automatic and Objective Scoring of Bradykinesia Using Orientation Sensors and Classification Algorithms
Abstract:
Correct assessment of bradykinesia is a key element in the diagnosis and monitoring of Parkinson's disease. Its evaluation is based on a careful assessment of symptoms and it is quantified using rating scales, where the Movement Disorders Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is the gold standard. Regardless of their importance, the bradykinesia-related items show low agreement between different evaluators. In this study, we design an applicable tool that provides an objective quantification of bradykinesia and that evaluates all characteristics described in the MDS-UPDRS. Twenty-five patients with Parkinson's disease performed three of the five bradykinesia-related items of the MDS-UPDRS. Their movements were assessed by four evaluators and were recorded with a nine degrees-of-freedom sensor. Sensor fusion was employed to obtain a 3-D representation of movements. Based on the resulting signals, a set of features related to the characteristics described in the MDS-UPDRS was defined. Feature selection methods were employed to determine the most important features to quantify bradykinesia. The features selected were used to train support vector machine classifiers to obtain an automatic score of the movements of each patient. The best results were obtained when seven features were included in the classifiers. The classification errors for finger tapping, diadochokinesis and toe tapping were 15–16.5%, 9.3–9.8%, and 18.2–20.2% smaller than the average interrater scoring error, respectively. The introduction of objective scoring in the assessment of bradykinesia might eliminate inconsistencies within evaluators and interrater assessment disagreements and might improve the monitoring of movement disorders.
Autors: Martinez Manzanera, O.;Roosma, E.;Beudel, M.;Borgemeester, R.;van Laar, T.;Maurits, N.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2016, volume: 63, issue:5, pages: 1016 - 1024
Publisher: IEEE
 
» A Method for Reducing Secondary Field Effects in Asymmetric MRI Gradient Coil Design
Abstract:
Goal: This research introduces an original method for the design of MRI gradient coils that reduces secondary field effects created by eddy current coupling. The method is able to deal with asymmetric coils and provides a new way to ensure a reduction in the magnitude of the eddy current induced fields. Methods: New constraints are introduced at the surface of passive objects to bind the normal field component below a given value. This value is determined by first treating the passive surface as an active surface, and then, calculating the ideal stream function on that surface to produce the desired secondary field. Two coils were designed, one to image the knee and the other to image the head and neck. Results: The secondary field was analyzed using linear regression and was found to improve the secondary field from 10.41 to 0.498 mT/m and from 7.84 to 0.286 mT/m in the examples used. The power loss in the passive structure also decreased to below 1% of the original value using the new method. Conclusion: The method shows the ability to constrain the field to values below the minimum seen under the traditional approaches. Significance: This will allow the design of asymmetric systems with highly linear, reduced magnitude of secondary fields and may lead to better image quality.
Autors: Smith, E.;Freschi, F.;Repetto, M.;Crozier, S.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2016, volume: 63, issue:5, pages: 924 - 932
Publisher: IEEE
 
» A Method to Evaluate Total Supply Capability of Distribution Systems Considering Network Reconfiguration and Daily Load Curves
Abstract:
The total supply capability (TSC) is an important index for assessing the reliability of a distribution power system. In this paper, two models to evaluate the TSC are established. In the first, the TSC is acquired with the conditions that all load outages can be restored via network reconfiguration with transformers' N-1 contingencies, i.e., that all constraints related to branch thermal ratings and bus-voltage limits can be satisfied following restoration for each N-1 contingency. The second model, which is revision of the first, considers the daily load curves for different classes of customers, e.g., residential, commercial and industrial. Both models can be formulated as mixed integer problems with second-order cone programming (MISOCP), which can be solved using commercially available optimization software. Two test systems are used to demonstrate the applicability of the presented models. Numerical results show that the presented model is more accurate than the previously published models. This proposed analytical approach can be applied in a range of network planning studies, e.g., for selecting appropriate ratings of transformers, or for optimal locating of circuit breakers and distributed energy resources.
Autors: Chen, K.;Wu, W.;Zhang, B.;Djokic, S.;Harrison, G.P.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2096 - 2104
Publisher: IEEE
 
» A Modified Relevance Vector Machine for PEM Fuel-Cell Stack Aging Prediction
Abstract:
Proton exchange membrane fuel cells (PEMFCs) are considered as a potential candidate in the green-energy applications in the near future. Comparing with other energy options, the PEMFCs need only hydrogen and air during operation. Meanwhile, as a by-product during operation, water is produced. This energy-conversion process is 100% eco-friendly and completely unharmful to the environment. However, PEMFCs are vulnerable to the impurities of hydrogen or fluctuation of operational condition, which could cause the degradation of output performance over time during operation. Thus, the prediction of the performance degradation is critical to the PEMFC system. In this work, a novel PEMFC performance-forecasting model based on a modified relevance vector machine (RVM) has been proposed, followed by a comparison with the approach of classic support vector machine (SVM). First, the theoretical formulation of RVM is briefly introduced, then the implementation steps of RVM using the experimental aging data sets of PEMFC stack output voltage are presented. By considering the specific feature of aging data-prediction problem, an innovative modified RVM formulation is proposed. The results of proposed modified RVM method are analyzed and compared to the results of SVM. The results have demonstrated that the modified RVM can achieve better performance of prediction than SVM, especially in the cases with relatively small training data sets. This novel method based on modified RVM approach has been demonstrated to show its effectiveness on forecasting the performance degradation of PEMFCs.
Autors: Wu, Y.;Breaz, E.;Gao, F.;Miraoui, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2573 - 2581
Publisher: IEEE
 
» A Modified RLS Algorithm for Online Estimation of Low-Frequency Oscillations in Power Systems
Abstract:
A number of methods have been proposed and implemented to improve system damping against low-frequency electromechanical oscillations in the power system. Among these, flexible ac transmission systems (FACTS) can be used to provide power oscillation damping (POD) function to the power system. The design of the POD algorithms in these devices requires estimation of the power oscillation frequency components and this is mostly achieved through the use of various filter combinations. However, these filter-based solutions are characterized by low bandwidth to extract the required signal components accurately, and this limits the dynamic performance of the FACTS controllers. Moreover, the filters are designed for specific frequencies, and a change in the system would reduce the performance of the methods. Thus, there is a need for a better estimation algorithm with fast and selective estimation of the required signal that is robust against system parameter uncertainties. In this paper, this is achieved by the use of a recursive least square algorithm that uses variable forgetting factor and a frequency adaptation mechanism. The investigated method has fast estimation in transient conditions without compromising its selectivity in steady state. The effectiveness of the proposed method is proven through simulation as well as experimental verification.
Autors: Beza, M.;Bongiorno, M.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 1703 - 1714
Publisher: IEEE
 
» A New Binary-Halved Clustering Method and ERT Processor for ASSR System
Abstract:
This paper presents an automatic speech–speaker recognition (ASSR) system implemented in a chip which includes a built-in extraction, recognition, and training (ERT) core. For VLSI design (here, ASSR system), the hardware cost and time complexity are always the important issues which are improved in this proposed design in two levels: 1) algorithmic and 2) architecture. At the algorithm level, a newly binary-halved clustering (BHC) is proposed to achieve low time complexity and low memory requirement. In addition, at the architecture level, a new ERT core is proposed and implemented based on data dependence and reuse mechanism to reduce the time and hardware cost as well. Finally, the chip implementation is synthesized, placed, and routed using TSMC 90-nm technology library. To verify the performance of the proposed BHC method, a case study is performed based on nine speakers. Moreover, the validation of the ASSR system is examined in two parts: 1) speech recognition and 2) speaker recognition. The results show that the proposed system can achieve 93.38% and 87.56% of recognition rates during speech and speaker recognition, respectively. Furthermore, the proposed ASSR chip includes 396k gate counts, and consumes power in 8.74 mW. Such results demonstrate that the performance of the proposed ASSR system is superior to the conventional systems.
Autors: Chou, C.-H.;Kuan, T.-W.;Barma, S.;Chen, B.-W.;Ji, W.;Peng, C.-H.;Wang, J.-F.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1871 - 1884
Publisher: IEEE
 
» A New European Settlement Map From Optical Remotely Sensed Data
Abstract:
An application of a general methodology for processing very high-resolution imagery to produce a European Settlement Map (ESM) in support of policy-makers is presented. The process mapped around 10 million of the European continent. The input image data are satellite SPOT-5/6 pan-sharpened multispectral images of 2.5- and 1.5-m spatial resolution, respectively. This is the first time that remote sensing technology demonstrates capability to produce a continental information layer using 2.5-m input images. Moreover, it is the highest resolution continental map produced so far. The presented workflow is data-driven and consists in fully automatic image information extraction based on textural and morphological image analysis. The learning method allows the processing of high-resolution image data using coarse resolution thematic layers as reference. Validation shows an overall accuracy of 96% with omission and commission errors less than 4% and 1%, respectively.
Autors: Florczyk, A.J.;Ferri, S.;Syrris, V.;Kemper, T.;Halkia, M.;Soille, P.;Pesaresi, M.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2016, volume: 9, issue:5, pages: 1978 - 1992
Publisher: IEEE
 
» A New Fuzzy Process Capability Estimation Method Based on Kernel Function and FAHP
Abstract:
Because of more and more complexity of an operation environment in today's industrial production process, it is difficult to monitor the process operation quality and to estimate the performance efficiency based on the existing mathematical model and knowledge. This paper proposes a new method to estimate the process capability, and a new criterion for capability and performance assessment. This method is based on kernel function and fuzzy analysis hierarchy process (FAHP), which can improve the adaptation of process capability analysis. The device process capability can be estimated by FAHP with main variables, which are determined by interpretive structure modeling. The estimators of these indices overcome uncertainties caused by data fluctuation in the traditional process capability, and could strongly improve the robustness and adaptability of the process capability estimation and diagnosis. The proposed methods are used in a simulation of the Tennessee Eastman process. The results demonstrate the efficiency and validity of the presented approach. The proposed method can provide more performance decision information of industrial process to help decision makers evaluate and diagnose the state of the production devices, and improve the process operations.
Autors: Geng, Z.;Wang, Z.;Peng, C.;Han, Y.;
Appeared in: IEEE Transactions on Engineering Management
Publication date: May 2016, volume: 63, issue:2, pages: 177 - 188
Publisher: IEEE
 
» A New Measure for Analyzing and Fusing Sequences of Objects
Abstract:
This work is related to the combinatorial data analysis problem of seriation used for data visualization and exploratory analysis. Seriation re-sequences the data, so that more similar samples or objects appear closer together, whereas dissimilar ones are further apart. Despite the large number of current algorithms to realize such re-sequencing, there has not been a systematic way for analyzing the resulting sequences, comparing them, or fusing them to obtain a single unifying one. We propose a new positional proximity measure that evaluates the similarity of two arbitrary sequences based on their agreement on pairwise positional information of the sequenced objects. Furthermore, we present various statistical properties of this measure as well as its normalized version modeled as an instance of the generalized correlation coefficient. Based on this measure, we define a new procedure for consensus seriation that fuses multiple arbitrary sequences based on a quadratic assignment problem formulation and an efficient way of approximating its solution. We also derive theoretical links with other permutation distance functions and present their associated combinatorial optimization forms for consensus tasks. The utility of the proposed contributions is demonstrated through the comparison and fusion of multiple seriation algorithms we have implemented, using many real-world datasets from different application domains.
Autors: Goulermas, J.;Kostopoulos, A.;Mu, T.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2016, volume: 38, issue:5, pages: 833 - 848
Publisher: IEEE
 
» A New Model of Electromechanical Relays for Predicting the Motion and Electromagnetic Dynamics
Abstract:
In this paper, a novel multiphysics and nonlinear model for electromechanical relays is presented. The electromagnetic dynamics is analyzed by calculating the total reluctance of the magnetic equivalent circuit (MEC), which is composed of a fixed length iron core and an angular air gap. Magnetic saturation and angular dependency of the reluctance are considered in the analysis. Then, an energy balance over the electromagnetic components of the system is used to obtain the torque which drives the movable armature. A planar mechanism of four rigid bodies, including spring-damping torques that restrict the motion and model the contact bounces that occur in the switchings, is proposed to explain the dynamics of the movable components. Experimental tests show the accuracy of the model in both the electromagnetic and the mechanical parts.
Autors: Ramirez-Laboreo, E.;Sagues, C.;Llorente, S.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2545 - 2553
Publisher: IEEE
 
» A New Transformerless Buck–Boost Converter With Positive Output Voltage
Abstract:
A new transformerless buck–boost converter with simple structure is proposed in this study. Compared with the traditional buck–boost converter, the proposed buck–boost converter’s voltage gain is squared times of the former’s and its output voltage polarity is positive. These advantages enable it to work in a wider range of positive output. The two power switches of the proposed buck–boost converter operate synchronously. In the continuous conduction mode (CCM), two inductors are magnetized and two capacitors are discharged during the switch-on period, while two inductors are demagnetized and two capacitors are charged during the switch-off period. The operating principles, the steady-state analyses, and the small-signal model for the proposed buck–boost converter operating in CCM are presented in detail. The power electronics simulator (PSIM) and the circuit experiments are provided to validate the effectiveness of the proposed buck–boost converter.
Autors: Miao, S.;Wang, F.;Ma, X.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2965 - 2975
Publisher: IEEE
 
» A Note on Delay Coordinates for Locally Observable Analytic Systems
Abstract:
In this short note, the problem of locally reconstructing the state of a nonlinear system is studied. To avoid computational difficulties arising in the numerical differentiation of the output, the so-called delay coordinates are considered. The assumptions of analyticity and (local) observability of the system are shown to imply that a family of mappings, induced by the delay coordinates and parameterized by a time delay parameter, gives a local diffeomorphism for generic values of such delay parameter on a certain set. A worked-out example illustrates the result.
Autors: Padoan, A.;Astolfi, A.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2016, volume: 61, issue:5, pages: 1409 - 1412
Publisher: IEEE
 
» A Note on the Normalization of Spanish Electricity Spot Prices
Abstract:
Merit order of renewable generation has produced an increasing, relevant number of zero values in Spanish electricity spot prices since 2010, in contrast with the rest of markets which rarely present zero values. This letter shows that existing methodologies for normalizing the price distribution fail to yield a proper normalization. This letter proposes a new algorithm based on Nataf transformation which addresses this issue and ensures a correct normalization. Numerical results validate the proposed algorithm.
Autors: Diaz, G.;Planas, E.-A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2499 - 2500
Publisher: IEEE
 
» A Novel Building and Tree Detection Method From LiDAR Data and Aerial Images
Abstract:
In recent decades, building and tree detection from LiDAR data and aerial imagery with high automation and accuracy level has been the focus of many researchers which was selected as the purpose of our research. At first, after data preprocessing, off-terrain objects (OTO) including trees and buildings were extracted from LiDAR data. Second, a number of features were produced as inputs of support vector machines (SVMs) to separate buildings from trees. In the SVM, an automatic procedure was used for selecting the training data. After separating the trees, mathematical morphology operations were used to eliminate small objects and fill small holes in the detected buildings and trees. Finally, k-means clustering algorithm was used to separate buildings with different heights. The obtained results for detected buildings and trees were evaluated by working group III/4 of ISPRS, which demonstrated a high rate of success. For completeness, correctness, and quality metrics in per area mode, average values of 88.70%, 95.60%, and 85.30% for buildings and 74.30%, 63.50%, and 52.10% for trees were obtained, respectively.
Autors: Zarea, A.;Mohammadzadeh, A.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2016, volume: 9, issue:5, pages: 1864 - 1875
Publisher: IEEE
 
» A Novel Peak Power Supply Noise Measurement and Adaptation System for Integrated Circuits
Abstract:
For 45-nm technologies and below, the maximum operation frequency of integrated circuits (ICs) has reached multiple gigahertz. At the same time, the size of modern ICs has increased significantly with several billions of transistors integrated on each die. When a large number of transistors switch at the same time, high current consumption is generated. The high current consumption combining with the parasitic resistance and inductance of the power supply network generates a significant power supply noise peak, which causes abnormal reset and generates excessive radiation emission, and hence needs to be accurately monitored, adapted, and mitigated. This paper presents a novel power supply noise measurement and adaptation system that can monitor the peak power supply noise and make dynamic adaptation within one clock cycle. The proposed system has been implemented in Nangate 45-nm technology. It has been proved that the proposed measurement and the adaptation system can successfully avoid the performance degradation or functional failure due to excessive power supply noise. The peak power supply noise monitoring accuracy is 5 mV. The adaptation reaction time is 75%–100% of single system clock cycle. The proposed system is robust against temperature and process variation, and of negligible area overhead and power consumption.
Autors: Wang, X.;Zhang, D.;Su, D.;Winemberg, L.;Tehranipoor, M.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1715 - 1727
Publisher: IEEE
 
» A Novel Quality Assessment Method for Pub _newline Flat Panel Display Defects
Abstract:
This paper presents a novel quality assessment method for flat panel display (FPD) defects, often called Muras, that employs the characteristics of the human visual system (HVS). Given a Mura image, the brightness difference between the Mura and its surrounding region is first adjusted to reflect the HVS’s property of background-adaptive perception. Then, the resulting adjusted Mura image is further processed using multiscale defect saliency acquisition (MDSA) to obtain a final Mura image with human perception characteristics. In the experiments, the quality scores of Mura test images are measured using the conventional and proposed methods. The results demonstrate that the quality of Mura evaluated by the proposed method correlates with the subjective quality to a much higher degree compared with the conventional methods.
Autors: Kim, H.;Gu, H.;Kim, Y.;Choi, K.;Ko, S.;
Appeared in: Journal of Display Technology
Publication date: May 2016, volume: 12, issue:5, pages: 500 - 505
Publisher: IEEE
 
» A Novel Wavelet-Based Ensemble Method for Short-Term Load Forecasting with Hybrid Neural Networks and Feature Selection
Abstract:
In this paper, a new ensemble forecasting model for short-term load forecasting (STLF) is proposed based on extreme learning machine (ELM). Four important improvements are used to support the ELM for increased forecasting performance. First, a novel wavelet-based ensemble scheme is carried out to generate the individual ELM-based forecasters. Second, a hybrid learning algorithm blending ELM and the Levenberg–Marquardt method is proposed to improve the learning accuracy of neural networks. Third, a feature selection method based on the conditional mutual information is developed to select a compact set of input variables for the forecasting model. Fourth, to realize an accurate ensemble forecast, partial least squares regression is utilized as a combining approach to aggregate the individual forecasts. Numerical testing shows that proposed method can obtain better forecasting results in comparison with other standard and state-of-the-art methods.
Autors: Li, S.;Wang, P.;Goel, L.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 1788 - 1798
Publisher: IEEE
 
» A Novel Window Function for Memristor Model With Application in Programming Analog Circuits
Abstract:
A mathematical model for the thin-film memristive devices found by Hewlett Packard Labs is proposed in this brief. By taking the current passing through the device into consideration and introducing two adjustable parameters, a novel window function is presented such that the resolution of the boundary lock, full scalability, and nonlinear ionic effects are simultaneously achieved. A comparison with some existing window functions is given. Finally, a programming analog circuit is designed to verify the applications and effectiveness of the memristive device equipped with the proposed window function.
Autors: Zha, J.;Huang, H.;Liu, Y.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 423 - 427
Publisher: IEEE
 
» A Profile Measurement System for Rail Quality Assessment During Manufacturing
Abstract:
Steel rails used in the transport sector and in industry are designed and manufactured to support high stress levels generated by high-speed and heavy-loaded modern trains. In the rail manufacturing process, one of the key stages is rolling, where fast, accurate, and repeatable rail profile measurement is a major challenge. In this paper, a rail profile measurement system (PMS) for rail rolling mills based on four conventional, inexpensive laser range finders is proposed. The range finders are calibrated using a common reference to properly express the point clouds generated by each range finder in the world coordinate system (WCS). The alignment of the point clouds to the rail model is performed by means of an efficient and robust registration method. Experiments carried out in a rail rolling mill demonstrate the accuracy and repeatability of the system; the maximum error is below 0.12%. All parallelizable tasks were designed and developed to be executed concurrently, achieving an acquisition rate of up to 210 fps.
Autors: Molleda, J.;Usamentiaga, R.;Millara, A.F.;Daniel, G.F.;Manso, P.;Suarez, C.M.;Garcia, I.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2684 - 2692
Publisher: IEEE
 
» A Quadrature Switched Capacitor Power Amplifier
Abstract:
This paper presents an all-digital class-G quadrature switched-capacitor power amplifier (Q-SCPA) implemented in 65 nm CMOS. It combines in-phase (I) and quadrature (Q) signals on a shared capacitor array. The I/Q signals are digitally weighted and combined in the charge domain. Quadrature summation results in a 3 dB signal loss; Hence the Q-SCPA utilizes a class-G dual-supply architecture to improve efficiency at backoff. Unlike polar/EER counterparts, the Q-SCPA requires no wideband phase modulator or delay matching circuitry. The Q-SCPA delivers a peak output power of 20.5 dBm with a peak PAE of 20%. It is measured with a 10 MHz, 64 QAM LTE signal, and achieves an ACLR of , with an 4%-rms.
Autors: Yuan, W.;Aparin, V.;Dunworth, J.;Seward, L.;Walling, J.S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1200 - 1209
Publisher: IEEE
 
» A Random Channel Sounding Decision Feedback Receiver for Two-Way Relay Communication With Pilotless Orthogonal Signaling and Physical-Layer Network Coding
Abstract:
We propose a decision feedback (DFB) receiver at the relay of a two-phase (2P) two-way relay (TWR) communication system that employs pilotless orthogonal modulation (such as frequency-shift keying) in the uplink and physical-layer network coding over finite field in the downlink. The proposed relay receiver is able to attain a performance very close to that of an ideal coherent detector in the presence of time-selective Rayleigh fading and additive white Gaussian noise in the uplinks. It exploits the fact that when the uplink symbols from the users are different, then the fading gains affecting these symbols can be separated and individually tracked at the relay. In essence, the proposed receiver performs random channel sounding although no actual pilots are transmitted. The channel estimates obtained this way can then be subsequently used in a coherent detector to improve the reliability of the relay detected data. To ensure fast convergence, we propose to kick start the DFB receiver using a partial-coherent detector developed earlier by the authors. We compare the performance of the proposed system against a similar 2P-TWR system that employs differential phase-shift keying (DPSK) in the uplink and DFB multiple-symbol differential detection at the relay. We found that the proposed pilotless orthogonal modulation system can actually attain a significantly lower bit error rate (BER) than its DPSK counterpart. For static fading and a BER of , the signal-to-noise ratio (SNR) gap between the two approaches is 1 dB in the binary case and 8 dB in the quaternary case. These gaps increase further with time-selective fading.
Autors: Li, X.;Ho, P.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3086 - 3099
Publisher: IEEE
 
» A Randomized Space-Time Spreading Scheme for Massive MIMO Channels
Abstract:
We consider a wireless transmission scheme based on randomized space-time spreading (STS) systems over massive multiple-input multiple-output (MIMO) channels. In the systems, the signals are spread by spreading matrices over time and antenna domains at the transmitter. We propose that the spreading matrices are generated from binary pseudo-noise (PN) and mutual quasi-orthogonal sequences, by partitioning each of the sequences into subsequences treated as real and imagination parts of rows or columns of a spreading matrix. We give a likelihood ascent search (LAS) detector for the STS systems and analyze its computational complexity. The number of multiplication and division operations for the LAS detector does not depend on its iterative process and the number of chips in the bit period. We use Monte Carlo method to solve the bit error rates (BERs) of the STS systems and to count numbers of evaluating bits in the LAS detectors. We choose the system parameters, such as the number of chips in the bit period and the transmission bit rates, according to BER performance and/or the numbers of evaluating bits attained from Monte-Carlo method. With the spreading matrices, the detection, and the suitable parameters, the STS systems achieve BERs near to their single-bit performance, which is the BER of a STS system with a single bit spread by orthonormal sequences at each transmitting antenna. We also compare our systems with V-BLAST-like spatial multiplexing systems with BPSK signals to show the improvement of the BER performance.
Autors: Chen, D.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2016, volume: 15, issue:5, pages: 3668 - 3678
Publisher: IEEE
 
» A Reference Voltage Interpolation-Based Calibration Method for Flash ADCs
Abstract:
A 6-bit flash analog-to-digital converter (ADC) using reference-voltage-interpolated calibration to improve linearity and reduce power dissipation is presented. In the ADC, the digital calibration logic employs the successive approximation algorithm and the minimized residue algorithm to determine precise calibration levels. Implemented by a 90-nm CMOS process, the proposed ADC can achieve a signal-to-noise-and-distortion ratio of 36 dB for a low input frequency and 33.5 dB for a Nyquist-rate input frequency at a 2-GS/s sampling rate. The peaks of integral and differential nonlinearities after calibration are 0.36 and 0.42 least significant bit, respectively. The power consumption is 25 mW at 2 GS/s from a 1.2 V supply. The core area is mm, and the figure of merit is 0.34 pJ/conversion step.
Autors: Chang, H.-Y.;Yang, C.-Y.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1728 - 1738
Publisher: IEEE
 
» A Resilient Framework for Fault-Tolerant Operation of Modular Multilevel Converters
Abstract:
This paper presents a resilient framework for fault-tolerant operation in modular multilevel converters (MMCs) to facilitate normal operation under internal and external fault conditions. This framework is realized by designing and implementing a supervisory algorithm and a postfault restoration scheme. The supervisory algorithm includes monitoring and decision-making units to detect and identify faults by analyzing the circulating current and submodule capacitor voltages in a very short time. The postfault restoration scheme is proposed to immediately replace the faulty submodule with the redundant healthy one. The restoration is achieved by virtue of a multilevel modular capacitor-clamped dc/dc converter (MMCCC), which is redundantly aggregated to each arm of the MMC. This design effectively guarantees smooth mode transition and handles the failure of multiple submodules in a short time interval. In addition, a modified modulation scheme is presented to ensure submodule capacitor voltage balancing of the MMC without implementing any additional hardware. Fast fault identification, a fully modular structure, and robust postfault restoration are the main features of the proposed framework. Digital time-domain simulation studies are conducted on a 21-level MMC to confirm the effectiveness and resilience of the proposed fault-tolerant framework during internal and external faults. Furthermore, the proposed framework is implemented in the FPGA-based RT-LAB real-time simulator platform to validate its resilience in a hardware-in-the-loop setup.
Autors: Ghazanfari, A.;Abdel-Rady I.Mohamed, Y.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2669 - 2678
Publisher: IEEE
 
» A Review on Recent Development of Spacecraft Attitude Fault Tolerant Control System
Abstract:
Motivated by several accidents, attitude control of a spacecraft subject to faults/failures has gained considerable attention in a wider range of aerospace engineering and academic communities. This paper is concerned with industrial practices and theoretical approaches for fault tolerant control (FTC) and fault detection and diagnosis (FDD) in spacecraft attitude control system. An overview on recent development of spacecraft attitude FTC system design is presented. The basis of a FTC system is introduced. The existing engineering FTC techniques and theoretical methodologies, including their advantages and disadvantages, are discussed. Moreover, closely associated with the reliability-relevant issues, recent progress in attitude FTC design strategies is reviewed. A brief review of some open problems in the general area of spacecraft attitude control design subject to components faults/failures is further concluded.
Autors: Yin, S.;Xiao, B.;Ding, S.X.;Zhou, D.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 3311 - 3320
Publisher: IEEE
 
» A Segmented Packet Collision Model for Smart Utility Networks Under WLAN Interferences
Abstract:
Smart metering utility network (SUN) is an emerging wireless technology for achieving intelligent control and information transfer in smart grid applications. However, the operation of SUNs on unlicensed bands is very sensitive to external interferences generated from other networks working on the same spectrum bands, such as wireless local area networks (WLANs). This paper aims to analyze packet error rate (PER) performance of a victim SUN receiver under the interferences of one or more WLAN transmitting nodes. To deal with a scenario leveraged by multiple random variables, such as offset between desired SUN data packet and WLAN packet, duration of WLAN data packet, and time interval between two consecutive WLAN packets, we propose a segmented packet collision model with the help of the probability theory. We first divide all the packets into small segments and then calculate the collision probability of each segment to acquire a more accurate bit error rate (BER). Then, based on different BERs in distinct segments of the desired SUN packet, average PER of the victim SUN receiver is obtained. Finally, the proposed analytical model is validated by simulations as an effort to evaluate PER performance of a SUN receiver under the WLAN interferences.
Autors: Chen, S.;Ma, R.;Chen, H.;Meng, W.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2016, volume: 15, issue:5, pages: 3506 - 3517
Publisher: IEEE
 
» A Self-Calibrated Bang–Bang Phase Detector for Low-Offset Time Signal Processing
Abstract:
This brief describes a self-calibrated bang–bang phase detector that has been implemented in a delay-locked loop (DLL) stabilized time-to-digital converter for high-energy physics applications. A two-state architecture is proposed, with a dedicated calibration state that measures the internal static phase offset and compensates for this offset in the other measurement state. The calibration is transparent to the DLL, runs continuously to compensate for radiation induced drifts, and shows a measured static phase offset variation of only 0.5 ps over different samples. The circuit has been designed and processed in a 40-nm CMOS technology.
Autors: Prinzie, J.;Steyaert, M.;Leroux, P.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 453 - 457
Publisher: IEEE
 
» A Self-Supervised Decision Fusion Framework for Building Detection
Abstract:
In this study, a new building detection framework for monocular satellite images, called self-supervised decision fusion (SSDF) is proposed. The model is based on the idea of self-supervision, which aims to generate training data automatically from each individual test image, without human interaction. This approach allows us to use the advantages of the supervised classifiers in a fully automated framework. We combine our previous supervised and unsupervised building detection frameworks to suggest a self-supervised learning architecture. Hence, we borrow the major strength of the unsupervised approach to obtain one of the most important clues, the relation of a building, and its cast shadow. This important information is, then, used in order to satisfy the requirement of training sample selection. Finally, an ensemble learning algorithm, called fuzzy stacked generalization (FSG), fuses a set of supervised classifiers trained on the automatically generated dataset with various shape, color, and texture features. We assessed the building detection performance of the proposed approach over 19 test sites and compare our results with the state of the art algorithms. Our experiments show that the supervised building detection method requires more than 30% of the ground truth (GT) training data to reach the performance of the proposed SSDF method. Furthermore, the SSDF method increases the F-score by 2 percentage points (p.p.) on the average compared to performance of the unsupervised method.
Autors: Senaras, C.;Yarman Vural, F.T.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2016, volume: 9, issue:5, pages: 1780 - 1791
Publisher: IEEE
 
» A Simple Model to Estimate Plantarflexor Muscle–Tendon Mechanics and Energetics During Walking With Elastic Ankle Exoskeletons
Abstract:
Goal: A recent experiment demonstrated that when humans wear unpowered elastic ankle exoskeletons with intermediate spring stiffness, they can reduce their metabolic energy cost to walk by ∼7%. Springs that are too compliant or too stiff have little benefit. The purpose of this study was to use modeling and simulation to explore the muscle-level mechanisms for the “sweet spot” in stiffness during exoskeleton assisted walking. Methods: We developed a simple lumped uniarticular musculoskeletal model of the plantarflexors operating in parallel with an elastic “exo-tendon.” Using an inverse approach with constrained kinematics and kinetics, we rapidly simulated human walking over a range of exoskeleton stiffness values and examined the underlying neuromechanics and energetics of the biological plantarflexors. Results: Stiffer ankle exoskeleton springs resulted in larger decreases in plantarflexor muscle forces, activations, and metabolic energy consumption. However, in the process of unloading the compliant biological muscle–tendon unit, the muscle fascicles experienced larger excursions that negatively impacted series elastic element recoil that is characteristic of a tuned “catapult mechanism.” Conclusion: The combination of disrupted muscle–tendon dynamics and the need to produce compensatory forces/moments to maintain overall net ankle moment invariance could explain the “sweet spot” in metabolic performance at intermediate ankle exoskeleton stiffness. Future work will aim to provide experimental evidence to support the model predictions presented here using ultrasound imaging of muscle-level dynamics during walking with elastic ankle exoskeletons. Significance: Engineers must account for the muscle-level effects of exoskeleton designs in order to achieve maximal performance objectives.
Autors: Sawicki, G.S.;Khan, N.S.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2016, volume: 63, issue:5, pages: 914 - 923
Publisher: IEEE
 
» A Single-Stage Single-Switch LED Driver Based on Class-E Converter
Abstract:
This paper proposes a single-stage single-switch light-emitting diode (LED) driver that integrates a buck–boost circuit with a Class-E resonant converter by sharing single-switch device. The buck–boost circuit, working as a power-factor correction (PFC) stage, operates in the discontinuous conduction mode (DCM) to shape the input current. The Class-E converter steps down the voltage to drive the LED. For specific component parameters, the Class-E converter can achieve soft-switching on the power switch and two rectifier diodes, and reduce switch losses at high frequencies. Electrolytic capacitors are used in the proposed converter to achieve a lower cost, but the system reliability decreases. To overcome this disadvantage, film capacitors can be used, but the current ripple increases. Neglecting the cost, multilayered film capacitors are the best option, if higher reliability and lower current ripple are required. The proposed driver features high efficiency (90.8%), and a high power factor (PF) (0.995). In this paper, analytical results and design considerations at 100 kHz are presented, and a 100-W prototype with 110 input was built to validate the theoretical analysis.
Autors: Wang, Y.;Huang, J.;Wang, W.;Xu, D.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2618 - 2626
Publisher: IEEE
 
» A Soft Decode–Compress–Forward Relaying Scheme for Cooperative Wireless Networks
Abstract:
This paper proposes a new technique for soft information relaying, which is based on a soft decode–compress–forward relay protocol. The proposed system provides a means of using distributed low-density parity-check (LDPC) coding in conjunction with higher order modulation, such as pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM), which is effective even under poor source–relay link conditions. Ordinarily, such schemes suffer from error propagation to the destination caused by incorrect decoding at the relay when the signal-to-noise ratio (SNR) on the source–relay link is low; however, our system avoids this problem by generating soft versions of the additional (parity-bearing) PAM symbols for transmission from the relay. The proposed technique of soft compression does not suffer from parity log-likelihood ratios (LLRs) converging to zero, as do many soft re-encoding techniques for turbo and LDPC codes. In the case of Gray-coded PAM/QAM signaling, we also propose a method of performing exact expectation-based soft modulation with low computational complexity. Furthermore, we propose a new model, which we refer to as the soft scalar model, for the overall source-to-destination channel encountered by the constellation symbols, and this model is used at the destination to compute LLRs for joint decoding of the distributed LDPC code. Simulation results demonstrate that the proposed scheme can provide good coding gain, diversity gain, and spectral efficiency under poor source–relay SNR conditions.
Autors: Jayakody, D.N.K.;Flanagan, M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3033 - 3041
Publisher: IEEE
 
» A Soft-Network-Coded Multilevel Forwarding Scheme for Multiple-Access Relay Systems
Abstract:
This paper proposes the novel technique of multilevel-threshold-based soft quantization (MLT-SQ) for a multiple-access relay system (MARS). The scheme is suitable for systems using binary phase-shift keying (BPSK) and network coding at the relay. In the proposed MLT-SQ protocol, the relay evaluates the reliabilities, which are expressed as log-likelihood ratios (LLRs), of the received signals from the two sources. It then computes the LLRs of the network-coded packet and quantizes these using a set of optimized multilevel thresholds, forwarding the resulting “quantized soft symbols” to the destination. We provide the derivation for the bit error rate (BER) at the destination, and based on this, we optimize the multilevel thresholds to minimize the BER. Simulation results are provided for the proposed MLT-SQ system, both without coding and for the case where low-density parity-check (LDPC) coding is employed. The proposed system achieves full diversity order. Compared with competing schemes, the performance of our system is superior in terms of BER when the same amount of channel state information (CSI) is exploited.
Autors: Jayakody, D.N.K.;Li, J.;Flanagan, M.F.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2016, volume: 65, issue:5, pages: 3430 - 3439
Publisher: IEEE
 
» A Space-Vector PWM-Based Voltage-Balancing Approach With Reduced Current Sensors for Modular Multilevel Converter
Abstract:
Arm voltage and submodule (SM) capacitor voltage balancing is a key factor for the safe and reliable operation of modular multilevel converters (MMCs). The arm voltage balancing is achieved through a zero-sequence voltage controller in carrier pulse-width modulation (CPWM). In this study, a dual space-vector pulse-width modulation (SVPWM) technique is proposed for an MMC, which eliminates the external controller for arm voltage balancing. In this approach, the three-phase top and bottom arms are independently controlled using SVPWM. In addition, the capacitor voltage balancing can be achieved using redundant switching vectors. However, this will increase the computational load on the space-vector modulator. Therefore, an external capacitor voltage-balancing approach is proposed to minimize the computational complexity. The proposed approach uses the direction of load current instead of the arm current in SM selection process. As such, the required number of current sensors is reduced to 50% in a three-phase system. The proposed modulation and voltage-balancing approach are simulated and experimentally verified on the MMC system with three-level flying capacitor (3L-FC) SMs. Simulation and experimental results show the successful balancing of the arm voltage and SM capacitors voltage.
Autors: Dekka, A.;Wu, B.;Zargari, N.R.;Lizana, R.;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2016, volume: 63, issue:5, pages: 2734 - 2745
Publisher: IEEE
 
» A State Machine Decoder for Phase Disposition Pulsewidth Modulation of Three-Phase Coupled-Inductor Semi-Bridge Converters
Abstract:
Coupled-inductor semi-bridge converters, assembled from magnetically linked pairs of complementary unidirectional phase legs, can achieve a substantially improved harmonic output voltage performance with the same number of silicon devices as traditional converters. However, they must be operated so as to ensure that a continuous common-mode current always flows through each coupled inductor, to ensure each phase leg can always produce the required switched output voltage. This is particularly challenging for a three-phase coupled-inductor bridge controlled by phase disposition (PD) modulation, since there is no direct correlation between the modulator output and the individual phase leg switching device commands. This paper presents a novel strategy to control each phase leg’s common-mode inductor current under PD modulation, by introducing a square wave offset signal into the modulator reference command, and feeding the modulator output through a postprocessing state machine to correctly switch each semi-bridge phase leg to maintain the required dc common-mode current. The strategy has been verified by detailed simulation studies and matching experimental results.
Autors: Teixeira, C.A.;McGrath, B.P.;Holmes, D.G.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2378 - 2386
Publisher: IEEE
 
» A Stochastic Geometry Approach to the Modeling of DSRC for Vehicular Safety Communication
Abstract:
Vehicle-to-vehicle safety communications based on the dedicated short-range communication technology have the potential to enable a set of applications that help avoid traffic accidents. The performance of these applications, largely affected by the reliability of communication links, stringently ties back to the MAC and PHY layer design, which has been standardized as IEEE 802.11p. The link reliabilities depend on the signal-to-interference-plus-noise ratio (SINR), which, in turn, depends on the locations and transmit power values of the transmitting nodes. Hence, an accurate network model needs to take into account the network geometry. For such geometric models, however, there is a lack of mathematical understanding of the characteristics and performance of IEEE 802.11p. Important questions such as the scalability performance of IEEE 802.11p have to be answered by simulations, which can be very time consuming and provide limited insights to future protocol design. In this paper, we investigate the performance of IEEE 802.11p by proposing a novel mathematical model based on queuing theory and stochastic geometry. In particular, we extend the Matérn hard-core type-II process with a discrete and nonuniform distribution, which is used to derive the temporal states of backoff counters. By doing so, concurrent transmissions from nodes within the carrier sensing ranges of each other are taken into account, leading to a more accurate approximation to real network dynamics. A comparison with Network Simulator 2 (ns2) simulations shows that our model achieves a good approximation in networks with different densities.
Autors: Tong, Z.;Lu, H.;Haenggi, M.;Poellabauer, C.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: May 2016, volume: 17, issue:5, pages: 1448 - 1458
Publisher: IEEE
 
» A Study on The Impact of Wind Farm Spatial Distribution on Power System Sub-Synchronous Oscillations
Abstract:
Motivated by several recent incidents, this paper investigates the impact of wind farm spatial distribution and shunt compensation levels on triggering system-side sub-synchronous oscillations (SSO) in wind-integrated power systems. Quantitative analysis on system eigenvalue sensitivities with respect to wind farm and transmission line parameters as well as system operating conditions is performed systematically to understand the multi-wind-farm-induced SSO. Coupling relationship for wind turbines with identical and different parameter settings on the studied SSO modes is investigated. Electro-magnetic simulations are performed on a multi-machine wind farm model derived from a practical wind-integrated power system, in order to verify the proposed study.
Autors: Wu, M.;Xie, L.;Cheng, L.;Sun, R.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2154 - 2162
Publisher: IEEE
 
» A Survey Of Architectural Approaches for Data Compression in Cache and Main Memory Systems
Abstract:
As the number of cores on a chip increases and key applications become even more data-intensive, memory systems in modern processors have to deal with increasingly large amount of data. In face of such challenges, data compression presents as a promising approach to increase effective memory system capacity and also provide performance and energy advantages. This paper presents a survey of techniques for using compression in cache and main memory systems. It also classifies the techniques based on key parameters to highlight their similarities and differences. It discusses compression in CPUs and GPUs, conventional and non-volatile memory (NVM) systems, and 2D and 3D memory systems. We hope that this survey will help the researchers in gaining insight into the potential role of compression approach in memory components of future extreme-scale systems.
Autors: Mittal, S.;Vetter, J.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2016, volume: 27, issue:5, pages: 1524 - 1536
Publisher: IEEE
 
» A Survey of Software Techniques for Using Non-Volatile Memories for Storage and Main Memory Systems
Abstract:
Non-volatile memory (NVM) devices, such as Flash, phase change RAM, spin transfer torque RAM, and resistive RAM, offer several advantages and challenges when compared to conventional memory technologies, such as DRAM and magnetic hard disk drives (HDDs). In this paper, we present a survey of software techniques that have been proposed to exploit the advantages and mitigate the disadvantages of NVMs when used for designing memory systems, and, in particular, secondary storage (e.g., solid state drive) and main memory. We classify these software techniques along several dimensions to highlight their similarities and differences. Given that NVMs are growing in popularity, we believe that this survey will motivate further research in the field of software technology for NVMs.
Autors: Mittal, S.;Vetter, J.S.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2016, volume: 27, issue:5, pages: 1537 - 1550
Publisher: IEEE
 
» A Switched-Capacitor RF Front End With Embedded Programmable High-Order Filtering
Abstract:
We propose a switched-capacitor radio-frequency (RF) front end achieving an equivalent high-order, tunable, highly linear RF filtering to improve the out-of-band (OB) blocker tolerance. RF input impedance matching, -path filtering, high-order discrete-time infinite-impulse response (IIR) filtering, and down-conversion are implemented using only switches and capacitors in a 0.1–0.7 GHz prototype with tunable center frequency, programmable filter order, and very high tolerance for OB blockers. The 40 nm CMOS frontend consumes 38.5–76.5 mA, achieves 40 dB gain, 24 dBm OB IIP3, 14.7 dBm 1 dB blocker compression point (B1dB) for a 30 MHz blocker offset, 6.8–9.7 dB noise figure, and 66 dB calibrated harmonic rejection ratio.
Autors: Xu, Y.;Kinget, P.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2016, volume: 51, issue:5, pages: 1154 - 1167
Publisher: IEEE
 
» A System for Controllable Magnetic Measurements of Hysteresis and Barkhausen Noise
Abstract:
A specially developed setup for precise measurement of magnetic hysteresis and Barkhausen noise is presented in this paper. A novelty of the setup consists in a unique combination of two main features: 1) an accurate local determination of the magnetic field and 2) an improved feedback control of the magnetization process. First, the magnetic field is measured by two Hall sensors at different distances above the sample. The sample field is determined by a linear extrapolation of these measured profiles of the tangential fields to the sample surface. Second, a digital feedback loop for precise control of the ac magnetization process is proposed. The feedback algorithm combines two methods of magnetizing signal adjustment: linear corrections of the magnetizing voltage amplitude and phase. The presented system is able to adjust the waveform of the magnetic induction or field to the prescribed sinusoidal or triangular shape. This provides stable and physically accurate results, which are independent of a specific experimental configuration.
Autors: Stupakov, A.;Perevertov, O.;Zablotskii, V.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2016, volume: 65, issue:5, pages: 1087 - 1097
Publisher: IEEE
 
» A Systematic Design Methodology of Asynchronous SAR ADCs
Abstract:
Successive approximation register (SAR) analog-to-digital converters (ADCs) are widely used in biomedical and portable/wearable electronic systems due to their excellent power efficiency. However, both the design and the optimization of high-performance SAR ADCs are time consuming, even for well-experienced circuit designers. For system designers, it is also hard to quickly evaluate the feasibility of a given specification in a process node. This paper presents a systematic sizing procedure for asynchronous SAR ADCs based on design considerations. A sizing tool based on the proposed design procedure is also implemented, the sizing results of which are highly competitive in comparison with other state-of-the-art manual works. Moreover, the sizing time is relatively short due to the efficient and effective search algorithms employed. In addition to the simulation results, two silicon proofs with different specifications and process nodes are provided to demonstrate the feasibility of this design methodology.
Autors: Huang, C.-P.;Lin, J.-M.;Shyu, Y.-T.;Chang, S.-J.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1835 - 1848
Publisher: IEEE
 
» A Two-Level Probabilistic Risk Assessment of Cascading Outages
Abstract:
Cascading outages in power systems can lead to major power disruptions and blackouts and involve a large number of different mechanisms. The typical development of a cascading outage can be split in two phases with different dominant cascading mechanisms. As a power system is usually operated in security, an initiating contingency cannot entail a fast collapse of the grid. However, it can trigger a thermal transient, increasing significantly the likelihood of additional contingencies, in a “slow cascade.” The loss of additional elements can then trigger an electrical instability. This is the origin of the subsequent “fast cascade,” where a rapid succession of events can lead to a major power disruption. Several models of probabilistic simulations exist, but they tend to focus either on the slow cascade or on the fast cascade, according to mechanisms considered, and rarely on both. We propose in this paper a decomposition of the analysis in two levels, able to combine probabilistic simulations for the slow and the fast cascades. These two levels correspond to these two typical phases of a cascading outage. Models are developed for each of these phases. A simplification of the overall methodology is applied to two test systems to illustrate the concept.
Autors: Henneaux, P.;Labeau, P.-E.;Maun, J.-C.;Haarla, L.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2016, volume: 31, issue:3, pages: 2393 - 2403
Publisher: IEEE
 
» A UWB-Based Sensor-to-Time Transmitter for RF-Powered Sensing Applications
Abstract:
An ultrawideband (UWB)-based sensor-to-time transmitter consisting of a remote control ( ) time-constant interface and an ultralow-power pulse generator is presented. The sensing information is directly extracted and transmitted in the time domain, exploiting UWB pulses with a high time-domain resolution. This approach eliminates the need for an analog-to-digital converter and baseband blocks of sensor tags; meanwhile, it reduces the number of bits to be transmitted for energy saving. The sensor interface measures the discharging time of the time constant proportional to the sensor variation. The UWB pulses are triggered with intervals of the discharging time, without any digitizing or modulations. The circuit prototype is implemented in the standard 0.18- CMOS process. Resistance measurement results show that the proposed system exhibits an effective number of resolution bits (ENOB) of 7.7 bits with an average relative error of 0.42% in the range of 200–1500 . The overall energy consumption of conversion and transmission per sample is measured to be 0.58 nJ with a 1.27-Vp-p pulse amplitude, which is favorable to radio-frequency-powered wireless sensing applications.
Autors: Mao, J.;Zou, Z.;Zheng, L.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2016, volume: 63, issue:5, pages: 503 - 507
Publisher: IEEE
 
» A Variable-Flux Hybrid-PM Switched-Flux Memory Machine for EV/HEV Applications
Abstract:
In this paper, a novel topology of hybrid-permanent-magnet switched-flux memory machine (HPM-SFMM) is proposed, which is characterized by a conventional SFPM machine with embedded “V”-shaped Al-Ni-Co magnet poles. The proposed machine combines the distinct synergies of torque enhancement in neodymium–iron–boron (NdFeB) PM and flux variability in aluminum–nickel–cobalt (AlNiCo) PM. By changing the magnetization directions of Al–Ni–Co magnets, the wide-speed-range high-efficiency operation can be readily achieved, which is highly favorable for automotive applications. The configuration and operating principle of the machine are first described, and the combination of stator/rotor pole numbers is optimized. In addition, the torque density/flux adjusting capability as the functions of dual-magnet dimensions are analytically derived. The magnet hybridizing proportion is optimized in order to achieve a favorite tradeoff between flux adjusting range and torque density improvement. Then, the electromagnetic performance of the proposed HPM-SFMM is investigated. Finally, a 12/14-stator/rotor pole prototype is fabricated to experimentally verify the analysis.
Autors: Yang, H.;Lin, H.;Zhu, Z.Q.;Wang, D.;Fang, S.;Huang, Y.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2016, volume: 52, issue:3, pages: 2203 - 2214
Publisher: IEEE
 
» A Variation-Tolerant Replica-Based Reference-Generation Technique for Single-Ended Sensing in Wide Voltage-Range SRAMs
Abstract:
The most promising SRAM cells capable of operating over a wide range of supply voltages contain single-ended read ports. These systems require an external reference voltage that suitably scales to enable error-free operation of the memory, as the supply voltage is scaled. This paper presents a replica-based reference-generation technique for wide voltage range SRAMs. The proposed approach tracks the memory over the large range of supply voltages, and is tunable to extend functionality down to subthreshold voltages. In addition, a tunable delay-based timing-generation scheme is employed to enable memory functionality, in the presence of increased variation at subthreshold voltages. Configuration bits are set using a random-sampling-based Built-in Self-Test algorithm that significantly speeds up the tuning process. A 4-kb array, using the conventional 8T cell, implemented in the UMC 130-nm process, is demonstrated to function from 1.2 V down to 310 mV (at 1.3 MHz and 6.45 pJ/access). The memory consumes 0.115 pJ/bit/access at the energy optimum point of 400 mV.
Autors: Rajanna, V.K.;Amrutur, B.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2016, volume: 24, issue:5, pages: 1663 - 1674
Publisher: IEEE
 

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