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Electrical and Electronics Engineering publications abstract of: 02-2012 sorted by title, page: 4
» An Asynchronous Analog Self-Powered CMOS Sensor-Data-Logger With a 13.56 MHz RF Programming Interface
Abstract:
Design and implementation of a hybrid energy scavenging integrated circuit (IC) is presented which includes an asynchronous self-powered analog sensor-data-logger (SDL) unit and a 13.56 MHz radio-frequency (RF) programming interface. The SDL unit operates on an event-based analog self-powering technique where the energy for sensing, computation and non-volatile storage is harvested directly from the signal being sensed. By exploiting operational primitives inherent in a controlled hot-electron injection mechanism, the SDL unit eliminates the need for voltage regulation, energy storage, ADCs, MCUs and RAMs which are commonly used in traditional energy scavenging sensors. Remote programming and data interrogation of the SDL unit are performed using an integrated 13.56 MHz RF back-telemetry interface. The interface consists of a 6-instruction set digital command and control unit based on a token-ring architecture; a high-voltage generator for programming floating-gate (FG) transistors; and an RF front-end unit for communicating with an external reader. We show that the self-powered design is suitable for integration with electro-capacitive transducers (e.g., piezoelectric transducers) that can generate open-load voltages greater than 5 V and drive currents less than 200 nA. Measured results from prototypes fabricated in a 0.5- m standard CMOS process demonstrate that the IC consumes less than 90 nA in the self-powering mode and less than 200 W of power in the RF-powering mode with an interrogation distance up to 40 mm. By combining self-powering and RF-powering, we show that the sensor experiences minimum down-time and can continuously monitor and record level-crossing statistics of different attributes of sensor signals.
Autors: Huang, C.;Chakrabartty, S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2012, volume: 47, issue:2, pages: 476 - 489
Publisher: IEEE
Full litterature document
 
» An Autonomous Resource Block Assignment Scheme for OFDMA-Based Relay-Assisted Cellular Networks
Abstract:
Terminal relaying offers an effective means for improving the performance of OFDMA-based wireless networks. However, revrr{with the increase in the number of relaying terminals (RTs), their coordination becomes a cumbersome task.} To address this drawback, in this paper an autonomous scheme is proposed whereby the RTs assign resource blocks (RBs) to incoming wireless terminals (WTs) in a way that minimizes the number of hit occurrences at which the same RB is assigned to multiple WTs. The proposed scheme uses cyclic group generators to determine the sequence of RBs to be assigned by each RT. This scheme is particularly beneficial in terminal relaying systems in which the distribution of the WTs is nonuniform and the channel quality indicators are not available. Simulation results show that the proposed scheme performs significantly better than currently available autonomous assignment schemes.
Autors: Fouad, Yaser M. M.;Gohary, Ramy H.;Yanikomeroglu, Halim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2012, volume: 11, issue:2, pages: 637 - 647
Publisher: IEEE
Full litterature document
 
» An Effective Correction Methodology for Interference of Stress-Induced Leakage Current in TDDB Evaluation of High- Dielectrics
Abstract:
A simple and effective correction methodology for interference of stress-induced leakage current (SILC) in time-dependent-dielectric-breakdown (TDDB) evaluation of high- dielectrics is reported. Unlike the violation of weakest link failure property found in conventional TDDB evaluation with SILC interference, we have demonstrated that time-to-failure distributions obtained with this new methodology restores this universal property. Excellent results in terms of improved time to failure and Weibull slope were obtained, thus providing a realistic TDDB projection. The algorithm of this methodology is easy to implement and can be used in daily TDDB evaluation.
Autors: Wu, E. Y.;
Appeared in: IEEE Electron Device Letters
Publication date: Feb 2012, volume: 33, issue:2, pages: 191 - 193
Publisher: IEEE
Full litterature document
 
» An Efficient Approach for Mobile Asset Tracking Using Contexts
Abstract:
Due to the heterogeneity involved in smart interconnected devices, cellular applications, and surrounding (GPS-aware) environments there is a need to develop a realistic approach to track mobile assets. Current tracking systems are costly and inefficient over wireless data transmission systems where cost is based on the rate of data being sent. Our aim is to develop an efficient and improved geographical asset tracking solution and conserve valuable mobile resources by dynamically adapting the tracking scheme by means of context-aware personalized route learning techniques. We intend to perform this tracking by proactively monitoring the context information in a distributed, efficient, and scalable fashion. Context profiles, which indicate the characteristics of a route based on environmental conditions, are utilized to dynamically represent the values of the asset's properties. We designed and implemented an adaptive learning based scheme that makes an optimized judgment of data transmission. This manuscript is complemented with theoretical and practical evaluations that prove that significant costs can be saved and operational efficiency can be achieved.
Autors: Balakrishnan, D.;Nayak, A.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2012, volume: 23, issue:2, pages: 211 - 218
Publisher: IEEE
Full litterature document
 
» An Efficient Camera Calibration Technique Offering Robustness and Accuracy Over a Wide Range of Lens Distortion
Abstract:
In the field of machine vision, camera calibration refers to the experimental determination of a set of parameters that describe the image formation process for a given analytical model of the machine vision system. Researchers working with low-cost digital cameras and off-the-shelf lenses generally favor camera calibration techniques that do not rely on specialized optical equipment, modifications to the hardware, or an a priori knowledge of the vision system. Most of the commonly used calibration techniques are based on the observation of a single 3-D target or multiple planar (2-D) targets with a large number of control points. This paper presents a novel calibration technique that offers improved accuracy, robustness, and efficiency over a wide range of lens distortion. This technique operates by minimizing the error between the reconstructed image points and their experimentally determined counterparts in “distortion free” space. This facilitates the incorporation of the exact lens distortion model. In addition, expressing spatial orientation in terms of unit quaternions greatly enhances the proposed calibration solution by formulating a minimally redundant system of equations that is free of singularities. Extensive performance benchmarking consisting of both computer simulation and experiments confirmed higher accuracy in calibration regardless of the amount of lens distortion present in the optics of the camera. This paper also experimentally confirmed that a comprehensive lens distortion model including higher order radial and tangential distortion terms improves calibration accuracy.
Autors: Rahman, T.;Krouglicof, N.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Feb 2012, volume: 21, issue:2, pages: 626 - 637
Publisher: IEEE
Full litterature document
 
» An Efficient Dictionary Learning Algorithm and Its Application to 3-D Medical Image Denoising
Abstract:
In this paper, we propose an efficient dictionary learning algorithm for sparse representation of given data and suggest a way to apply this algorithm to 3-D medical image denoising. Our learning approach is composed of two main parts: sparse coding and dictionary updating. On the sparse coding stage, an efficient algorithm named multiple clusters pursuit (MCP) is proposed. The MCP first applies a dictionary structuring strategy to cluster the atoms with high coherence together, and then employs a multiple-selection strategy to select several competitive atoms at each iteration. These two strategies can greatly reduce the computation complexity of the MCP and assist it to obtain better sparse solution. On the dictionary updating stage, the alternating optimization that efficiently approximates the singular value decomposition is introduced. Furthermore, in the 3-D medical image denoising application, a joint 3-D operation is proposed for taking the learning capabilities of the presented algorithm to simultaneously capture the correlations within each slice and correlations across the nearby slices, thereby obtaining better denoising results. The experiments on both synthetically generated data and real 3-D medical images demonstrate that the proposed approach has superior performance compared to some well-known methods.
Autors: Li, S.;Fang, L.;Yin, H.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2012, volume: 59, issue:2, pages: 417 - 427
Publisher: IEEE
Full litterature document
 
» An Efficient Game Form for Unicast Service Provisioning
Abstract:
We consider the decentralized bandwidth/rate allocation problem in unicast service provisioning with strategic users. We present a mechanism/game form which possesses the following properties when the users' utilities are concave: 1) It implements in Nash equilibria the solution of the corresponding centralized rate allocation problem in unicast service provisioning. 2) It is individually rational. 3) It is budget-balanced at all Nash equilibria of the game induced by the mechanism/game form as well as off equilibrium. When the users' utilities are quasi-concave the mechanism possesses properties 2) and 3) stated above. Moreover, every Nash equilibrium of the game induced by the proposed mechanism results in a Walrasian equilibrium.
Autors: Kakhbod, A.;Teneketzis, D.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2012, volume: 57, issue:2, pages: 392 - 404
Publisher: IEEE
Full litterature document
 
» An Efficient Hybrid GO-PWS Algorithm to Analyze Conformal Serrated-Edge Reflectors for Millimeter-Wave Compact Range
Abstract:
A method to analyze parabolic reflectors with arbitrary piecewise rim is presented in this communication. This kind of reflectors, when operating as collimators in compact range facilities, needs to be large in terms of wavelength. Their analysis is very inefficient, when it is carried out with fullwave/MoM techniques, and it is not very appropriate for designing with PO techniques. Also, fast GO formulations do not offer enough accuracy to reach performance results. The proposed algorithm is based on a GO-PWS hybrid scheme, using analytical as well as non-analytical formulations. On one side, an analytical treatment of the polygonal rim reflectors is carried out. On the other side, non-analytical calculi are based on efficient operations, such as order 2-dimensional FFT. A combination of these two techniques in the algorithm ensures real ad-hoc design capabilities, reached through analysis speedup. The purpose of the algorithm is to obtain an optimal conformal serrated-edge reflector design through the analysis of the field quality within the quiet zone that it is able to generate in its forward half space.
Autors: Munoz-Acevedo, A.;Sierra-Castaner, M.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2012, volume: 60, issue:2, pages: 1192 - 1197
Publisher: IEEE
Full litterature document
 
» An Efficient Layered Decoding Architecture for Nonbinary QC-LDPC Codes
Abstract:
Compared to binary low-density parity-check (LDPC) codes, nonbinary LDPC codes have better error performance when the code length is moderate. This paper presents an efficient layered decoder architecture for nonbinary quasi-cyclic (QC) LDPC codes using the proposed barrel-shifter-based permutation network and minimum value filter which is used to determine the first few smallest values from a given set. Through the permutation network, the decoding operations related to the multiplications over finite fields can be efficiently handled in the check-node operations, which simplifies the permutations in the variable-node operations and, hence, enables the layered decoder to be realized efficiently. In order to increase the throughput, we utilize the proposed permutation network and the minimum value filter to devise a selective-input min-max decoder architecture. Using a 90-nm CMOS process, we implemented three nonbinary decoders to demonstrate the proposed techniques.
Autors: Ueng, Y.-L.;Leong, C.-Y.;Yang, C.-J.;Cheng, C.-C.;Liao, K.-H.;Chen, S.-W.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2012, volume: 59, issue:2, pages: 385 - 398
Publisher: IEEE
Full litterature document
 
» An Efficient Lyapunov Function for Discrete T–S Models: Observer Design
Abstract:
This paper deals with the design of a new observer synthesis for discrete Takagi–Sugeno (T–S) fuzzy models. It is well established that quadratic synthesis for discrete T–S models and/or linear parameter-varying systems can be outperformed easily via nonquadratic syntheses. Several Lyapunov functions can be used. Nevertheless, this paper shows that with a “small” change in the initial Lyapunov function, a “better” (in the sense of solutions to the linear matrix inequality constraints problem) Lyapunov function can be reached. This one can introduce very important improvements.
Autors: Guerra, T. M.;Kerkeni, H.;Lauber, J.;Vermeiren, L.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2012, volume: 20, issue:1, pages: 187 - 192
Publisher: IEEE
Full litterature document
 
» An electric field screen prevents captured insects from escaping by depriving bioelectricity generated through insect movements
Abstract:

Highlights

? We constructed a simplified electric field screen to trap insects. ? The screen consists of an insulated conductor wire (-) and an earthed net (+). ? The electric power was generated by muscular movements of the trapped insect. ? The earthed net deprived the negative charges of the insect to make it net positive. ? These insects were drawn toward the negative charge of the opposite pole.


Autors: An insulated conductor wire (ICW) paralleled with an earthed net was used to observe movements by vinegar flies in relation to their electricity release. ICW was negatively charged to create a positive charge on the net. At particular voltages, flies
Appeared in: Journal of Electrostatics
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» An Electromagnetic Circuit Simulator for Power Electronics
Abstract:
A method for solving the full equations of Maxwell for circuits with discrete nonlinear, nonideal elements is presented. To this end, the method of moments is used in combination with a classical circuit simulator. Both operate in the frequency domain. A few methods to greatly accelerate the calculations are also presented. The methods are implemented and tested in Matlab.
Autors: Zwysen, J.;Jacqmaer, P.;Gelagaev, R.;Driesen, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 799 - 802
Publisher: IEEE
Full litterature document
 
» An Electronic Patch for Wearable Health Monitoring by Reflectance Pulse Oximetry
Abstract:
We report the development of an Electronic Patch for wearable health monitoring. The Electronic Patch is a new health monitoring system incorporating biomedical sensors, microelectronics, radio frequency (RF) communication, and a battery embedded in a 3-dimensional hydrocolloid polymer. In this paper the Electronic Patch is demonstrated with a new optical biomedical sensor for reflectance pulse oximetry so that the Electronic Patch in this case can measure the pulse and the oxygen saturation. The reflectance pulse oximetry solution is based on a recently developed annular backside silicon photodiode to enable low power consumption by the light emitting components. The Electronic Patch has a disposable part of soft adhesive hydrocolloid polymer and a reusable part of hard polylaurinlactam. The disposable part contains the battery. The reusable part contains the reflectance pulse oximetry sensor and microelectronics. The reusable part is 'clicked' into the disposable part when the patch is prepared for use. The patch has a size of 88 mm by 60 mm and a thickness of 5 mm.
Autors: Haahr, R. G.;Duun, S. B.;Toft, M. H.;Belhage, B.;Larsen, J.;Birkelund, K.;Thomsen, E. V.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2012, volume: 6, issue:1, pages: 45 - 53
Publisher: IEEE
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» An electrooptic probe to determine internal electric fields in a piezoelectric transformer
Abstract:
A technique using the electrooptic effect to determine the output voltage of an optically clear LiNbO3 piezoelectric transformer was developed and explored. A brief mathematical description of the solution is provided, as well as experimental data demonstrating a linear response under ac resonant operating conditions. A technique to calibrate the diagnostic was developed and is described. Finally, a sensitivity analysis of the electrooptic response to variations in angular alignment between the LiNbO3 transformer and the laser probe are discussed.
Autors: Norgard, Peter;Kovaleski, Scott;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 025106 - 025106-7
Publisher: IEEE
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» An Embedded DRAM Technology for High-Performance NAND Flash Memories
Abstract:
An embedded DRAM using a standard NAND flash memory process has been demonstrated for the first time. This embedded DRAM without extra costly manufacturing process realizes 2.4 mm /Mb macro density and provides large-capacity on-chip page buffers and data caches for NAND flash memories to enhance their performances. A 32 KB DRAM buffer macro with 1.5 cell has been fabricated with a 32 nm NAND flash memory process. Even with small 3 fF cell using a planar MOS capacitor, an enough 100 mV cell signal has been obtained by introducing a technique to self-boost cell node up to 4 V using a merit of high-voltage NAND flash process, and two techniques to curtail parasitic bitline capacitance down to 60 fF at 128 wordlines per bitline. An undershoot problem of cell nodes due to unwanted plateline bounce is resolved by a two-step-rise/fall wordline scheme. Installation of dummy cell scheme to obtain a half of “1” data (not an average of “1” and “0” data) cuts out 32 KB macro size by 1.3% while suppressing mismatch to 3 mV at the grounded bitline precharge. The 32 KB test vehicle shows 90 ns random cycle time with 15 ns burst cycle time (66 Mb/s/pin). The measured characteristics of 2 bit error rater (BER) by soft error and 10 ms data retention at 85 are enough for page buffer application in a NAND flash memory. The measured active current of 32 KB macro is 7 mA at 90 ns random cycle, but only 3.2 mA at practical use of 15 ns burst with 256B page access.
Autors: Takashima, D.;Noguchi, M.;Shibata, N.;Kanda, K.;Sukegawa, H.;Fujii, S.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2012, volume: 47, issue:2, pages: 536 - 546
Publisher: IEEE
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» An Energy-Efficient, Adiabatic Electrode Stimulator With Inductive Energy Recycling and Feedback Current Regulation
Abstract:
In this paper, we present a novel energy-efficient electrode stimulator. Our stimulator uses inductive storage and recycling of energy in a dynamic power supply. This supply drives an electrode in an adiabatic fashion such that energy consumption is minimized. It also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The dynamic power supply allows efficient transfer of energy both to and from the electrode and is based on a DC-DC converter topology that we use in a bidirectional fashion in forward-buck or reverse-boost modes. In an exemplary electrode implementation intended for neural stimulation, we show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard CMOS process. This stimulator achieves a 2x–3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply. We perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. This theoretical analysis reveals that further improvements in energy efficiency may be achievable with better implementations in the future. Our electrode stimulator could be widely useful for neural, cardiac, retinal, cochlear, muscular and other biomedical implants where low power operation is important.
Autors: Arfin, S. K.;Sarpeshkar, R.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2012, volume: 6, issue:1, pages: 1 - 14
Publisher: IEEE
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» An Enhanced Bag-of-Visual Word Vector Space Model to Represent Visual Content in Athletics Images
Abstract:
Images that have a different visual appearance may be semantically related using a higher level conceptualization. However, image classification and retrieval systems tend to rely only on the low-level visual structure within images. This paper presents a framework to deal with this semantic gap limitation by exploiting the well-known bag-of-visual words (BVW) to represent visual content. The novelty of this paper is threefold. First, the quality of visual words is improved by constructing visual words from representative keypoints. Second, domain specific “non-informative visual words” are detected which are useless to represent the content of visual data but which can degrade the categorization capability. Distinct from existing frameworks, two main characteristics for non-informative visual words are defined: a high document frequency (DF) and a small statistical association with all the concepts in the collection. The third contribution in this paper is that a novel method is used to restructure the vector space model of visual words with respect to a structural ontology model in order to resolve visual synonym and polysemy problems. The experimental results show that our method can disambiguate visual word senses effectively and can significantly improve classification, interpretation, and retrieval performance for the athletics images.
Autors: Kesorn, K.;Poslad, S.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2012, volume: 14, issue:1, pages: 211 - 222
Publisher: IEEE
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» An Event-Driven Multi-Kernel Convolution Processor Module for Event-Driven Vision Sensors
Abstract:
Event-Driven vision sensing is a new way of sensing visual reality in a frame-free manner. This is, the vision sensor (camera) is not capturing a sequence of still frames, as in conventional video and computer vision systems. In Event-Driven sensors each pixel autonomously and asynchronously decides when to send its address out. This way, the sensor output is a continuous stream of address events representing reality dynamically continuously and without constraining to frames. In this paper we present an Event-Driven Convolution Module for computing 2D convolutions on such event streams. The Convolution Module has been designed to assemble many of them for building modular and hierarchical Convolutional Neural Networks for robust shape and pose invariant object recognition. The Convolution Module has multi-kernel capability. This is, it will select the convolution kernel depending on the origin of the event. A proof-of-concept test prototype has been fabricated in a 0.35 CMOS process and extensive experimental results are provided. The Convolution Processor has also been combined with an Event-Driven Dynamic Vision Sensor (DVS) for high-speed recognition examples. The chip can discriminate propellers rotating at 2 k revolutions per second, detect symbols on a 52 card deck when browsing all cards in 410 ms, or detect and follow the center of a phosphor oscilloscope trace rotating at 5 KHz.
Autors: Camunas-Mesa, L.;Zamarreno-Ramos, C.;Linares-Barranco, A.;Acosta-Jimenez, A. J.;Serrano-Gotarredona, T.;Linares-Barranco, B.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Feb 2012, volume: 47, issue:2, pages: 504 - 517
Publisher: IEEE
Full litterature document
 
» An Experimental Comparison of Production Planning Using Clearing Functions and Iterative Linear Programming-Simulation Algorithms
Abstract:
We compare the performance of three algorithms for production planning with workload-dependent lead times. These include a clearing function model using two different methods for estimating the clearing functions, and two iterative algorithms that combine linear programming and simulation models. Our experimental comparison uses a simulation model of a re-entrant bottleneck system built with attributes of a real-world semiconductor fabrication environment. We vary the bottleneck utilization, demand patterns, the mean time to failure, and the mean time to repair. Results indicate that the clearing function model performs better than the iterative algorithms on the scaled-down system considered, giving less variable production plans and higher profit values.
Autors: Kacar, N. B.;Irdem, D. F.;Uzsoy, R.;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Feb 2012, volume: 25, issue:1, pages: 104 - 117
Publisher: IEEE
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» An experimental study on time delay control of actuation system of tilt rotor unmanned aerial vehicle
Abstract:
This paper presents an actuation control system for the Smart Unmanned Aerial Vehicle (SUAV), a tilt rotor aircraft that is being developed by the Korea Aerospace Research Institute. The actuation system, which consists of flaperon, rotor, and nacelle tilt, should be controlled to track the position command sent from the flight controller. However, substantial variations in the aerodynamic load on the actuation system make it difficult to achieve the desired level of control performance. In this study, the actuation system was controlled using the Time Delay Control (TDC) law. The experimental results show that the following control performance specifications are completely satisfied under load variation from 0 to 455 kgf: bandwidth of 4 Hz, overshoot of 2.5%, and steady state error of 1% for flaperon and rotor actuation system. Especially, the accuracy was within the noise level of the steady state position error over broad ranges of the load. In addition, the command filter was applied to the TDC command to mitigate the effects of the phase delay that occurs when a sinusoidal command is applied. Furthermore, an actual flight test was performed, which clearly showed the effectiveness of the proposed control scheme. This promising control performance shows that TDC is an effective alternative for controlling the actuation system of the SUAV with substantial load variation.
Autors: Jinoh Lee, Changsun Yoo, Yea-Seok Park, Bumjin Park, Soo-Jin Lee, ...
Appeared in: Mechatronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» An Experimentally Verified Active Gate Control Method for the Series Connection of IGBT/Diodes
Abstract:
The series connection of insulated gate bipolar transistor (IGBT)/diode devices allows the operation at voltage levels higher than the rated voltage of one IGBT/diode. However, due to individual parameter differences of the series-connected IGBT/diodes, it is difficult to ensure a proper voltage balance between them, and transient or steady-state voltage unbalances could cause the failure of these devices. This paper presents an active gate driver developed by the authors that is suitable for the series connection of IGBTs. The proposed active gate driver achieves the transient and steady-state voltage balance between the series-connected IGBT/diode devices. The effectiveness of the gate driver and the active gate control method has been experimentally validated, and promising results have been obtained.
Autors: Baraia, I.;Barrena, J.;Abad, G.;Canales Segade, J.M.;Iraola, U.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Feb 2012, volume: 27, issue:2, pages: 1025 - 1038
Publisher: IEEE
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» An explosively driven high-power microwave pulsed power system
Abstract:
The increased popularity of high power microwave systems and the various sources to drive them is the motivation behind the work to be presented. A stand-alone, self-contained explosively driven high power microwave pulsed power system has been designed, built, and tested at Texas Tech University's Center for Pulsed Power and Power Electronics. The system integrates four different sub-units that are composed of a battery driven prime power source utilizing capacitive energy storage, a dual stage helical flux compression generator as the main energy amplification device, an integrated power conditioning system with inductive energy storage including a fast opening electro-explosive switch, and a triode reflex geometry virtual cathode oscillator as the microwave radiating source. This system has displayed a measured electrical source power level of over 5 GW and peak radiated microwaves of about 200 MW. It is contained within a 15 cm diameter housing and measures 2 m in length, giving a housing volume of slightly less than 39 l. The system and its sub-components have been extensively studied, both as integrated and individual units, to further expand on components behavior and operation physics. This report will serve as a detailed design overview of each of the four subcomponents and provide detailed analysis of the overall system performance and benchmarks.
Autors: Elsayed, M. A.;Neuber, A. A.;Dickens, J. C.;Walter, J. W.;Kristiansen, M.;Altgilbers, L. L.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 024705 - 024705-11
Publisher: IEEE
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» An Extended Field Reconstruction Method for Modeling of Switched Reluctance Machines
Abstract:
This paper presents an extended Field Reconstruction Method (FRM) to model a Switched Reluctance Machine (SRM), which is set apart from other electric machines by its double-saliency and magnetic saturation. Traditional magnetic models of SRM developed using Finite Element Analysis (FEA) are computationally inefficient. This, in turn, limits their application in simulation of SRM drive system especially under iterative optimization procedures. FRM can significantly reduce the computational time by utilizing a small number of static magnetic field snapshots to establish the basis functions which are then used to reconstruct the magnetic field with high accuracy. In this paper an extended version of FRM is introduced within which effects of magnetic saturation and double saliency are taken into account. Results from FRM, FEA and experiments are compared and good accuracy is observed.
Autors: Lin, C.;Wang, W.;McDonough, M.;Fahimi, B.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 1051 - 1054
Publisher: IEEE
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» An Extended Visual Cryptography Algorithm for General Access Structures
Abstract:
Conventional visual secret sharing schemes generate noise-like random pixels on shares to hide secret images. It suffers a management problem, because of which dealers cannot visually identify each share. This problem is solved by the extended visual cryptography scheme (EVCS), which adds a meaningful cover image in each share. However, the previous approaches involving the EVCS for general access structures suffer from a pixel expansion problem. In addition, the visual cryptography (VC)-based approach needs a sophisticated codebook design for various schemes. In this paper, we propose a general approach to solve the above-mentioned problems; the approach can be used for binary secret images in noncomputer-aided decryption environments. The proposed approach consists of two phases. In the first phase, based on a given access structure, we construct meaningless shares using an optimization technique and the construction for conventional VC schemes. In the second phase, cover images are added in each share directly by a stamping algorithm. The experimental results indicate that a solution to the pixel expansion problem of the EVCS for GASs is achieved. Moreover, the display quality of the recovered image is very close to that obtained using conventional VC schemes.
Autors: Lee, K.-H.;Chiu, P.-L.;
Appeared in: IEEE Transactions on Information Forensics and Security
Publication date: Feb 2012, volume: 7, issue:1, pages: 219 - 229
Publisher: IEEE
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» An Extensible Framework for Improving a Distributed Software System's Deployment Architecture
Abstract:
A distributed system's allocation of software components to hardware nodes (i.e., deployment architecture) can have a significant impact on its quality of service (QoS). For a given system, there may be many deployment architectures that provide the same functionality, but with different levels of QoS. The parameters that influence the quality of a system's deployment architecture are often not known before the system's initial deployment and may change at runtime. This means that redeployment of the software system may be necessary to improve the system's QoS properties. This paper presents and evaluates a framework aimed at finding the most appropriate deployment architecture for a distributed software system with respect to multiple, possibly conflicting QoS dimensions. The framework supports formal modeling of the problem and provides a set of tailorable algorithms for improving a system's deployment. We have realized the framework on top of a visual deployment architecture modeling and analysis environment. The framework has been evaluated for precision and execution-time complexity on a large number of simulated distributed system scenarios, as well as in the context of two third-party families of distributed applications.
Autors: Malek, Sam;Medvidovic, Nenad;Mikic-Rakic, Marija;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Feb 2012, volume: 38, issue:1, pages: 73 - 100
Publisher: IEEE
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» An FPGA-Based Hardware Implementation of Configurable Pixel-Level Color Image Fusion
Abstract:
Image fusion has attracted a lot of interest in recent years. As a result, different fusion methods have been proposed mainly in the fields of remote sensing and computer (e.g., night) vision, while hardware implementations have been also presented to tackle real-time processing in different application domains. In this paper, a linear pixel-level fusion method is employed and implemented on a field-programmable-gate-array-based hardware system that is suitable for remotely sensed data. Our work incorporates a fusion technique (called VTVA) that is a linear transformation based on the Cholesky decomposition of the covariance matrix of the source data. The circuit is composed of different modules, including covariance estimation, Cholesky decomposition, and transformation ones. The resulted compact hardware design can be characterized as a linear configurable implementation since the color properties of the final fused color can be selected by the user in a way of controlling the resulting correlation between color components.
Autors: Besiris, D.;Tsagaris, V.;Fragoulis, N.;Theoharatos, C.;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Feb 2012, volume: 50, issue:2, pages: 362 - 373
Publisher: IEEE
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» An Ill-Structured PBL-Based Microprocessor Course Without Formal Laboratory
Abstract:
This paper introduces a problem-based learning (PBL) microprocessor application course designed according to the following strategies: 1) hands-on training without having a formal laboratory, and 2) intense student-centered cooperative learning through an ill-structured problem. PBL was adopted as the core educational technique of the course to accomplish student learning outcomes such as fundamental knowledge acquisition and applications, practical design experiences, problem-solving skills, higher-order thinking, teamwork and communication skills, and lifelong self-directed learning capability. In the designed course, students were required to build their own hardware system on a breadboard and learn how to program, download, and execute from a student mentor's demonstration. Students were also asked to choose a design topic for their team project with minimum guidelines and were encouraged to learn whatever was necessary to accomplish the project autonomously. The course has been offered for two years and has obtained overwhelming positive feedback from students.
Autors: Kim, J.;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2012, volume: 55, issue:1, pages: 145 - 153
Publisher: IEEE
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» An Improved Cross-Entropy Method Applied to Inverse Problems
Abstract:
An improved cross-entropy method for global optimizations of inverse problems with continuous variables is proposed. To enhance the convergence speed, improvements on both algorithm development and iterative process are introduced. To monitor and guide the searching process, the design space is divided into subdomains and three indicators are assigned for each subdomain in order to evaluate its performances. To balance exploitation and exploration searches, the whole iterative process is divided a diversification and an intensification phase. In the diversification phase, a novel mechanism is introduced to increase the sampling diversity to avoid the solution being trapped onto a local optimum; in the intensification phase, the strategy of shifting away from the worst subdomains equips the algorithm with enhanced convergence rates. The proposed method is applied to a mathematical function and the TEAM Workshop problem 22. Comparisons with its counterparts are made to demonstrate the effectiveness of the proposed work.
Autors: An, S.;Yang, S.;Ho, S. L.;Ni, P.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 327 - 330
Publisher: IEEE
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» An improved microwave silicon MESFET
Abstract:
An improved silicon MESFET with a 1; gate is described which has a maximum frequency of oscillation of 15 GHz. The improvement over previous MESFET's has been achieved by reducing the influence of the resistance of the gate metallization and by decreasing the gate-pad parasitics. Maximum available gain MAG is now 5 dB at 7 GHz and the optimum noise figureF0is 5 dB at 6 GHz. Below about 6 GHz the device is conditionally unstable. Unilateral gainUup to 3 GHz is 20 dB. The investigation indicates that not all parasitics have been removed. If the series resistance of the channel in the source-gate spacing could be decreased,fmaxshould approach 35 GHz the estimated value of the intrinsic transistor.
Autors: W. Baechtold, P. Wolf
Appeared in: Solid-State Electronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» An Improved Population-Based Incremental Learning Method for Objects Buried in Planar Layered Media
Abstract:
An evolutionary algorithm, the estimation of distribution algorithm (EDA), is used to reconstruct the objects that buried in planar layered media. It is essential that fast forward solvers be used to solve the forward scattering problem for the nonlinear inverse scattering methods, since it can avoid errors by approximation. The EDA is a predominant all-round optimizing method in the macroscopic simulation of evolution process species of nature. Recent studies have shown that the EDA provides better solution for nonlinear problems than the microscopic evolutionary algorithm, such as genetic algorithm (GA) in some cases. The EDA is simpler, both computationally and theoretically, than the GA. We discuss how this can be used to calculate the permittivity and conductivity of the targets. We show preliminary results indicating the potential of reconstruction for buried objects. Compared with other methods, the experiment result shows that the EDA algorithm reduces the number of iteration.
Autors: Chen, X.;Lei, G.;Yang, G.;Shao, K. R.;Guo, Y.;Zhu, J.;Lavers, J. D.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 1027 - 1030
Publisher: IEEE
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» An Improvement of Convergence in Finite Element Analysis With Infinite Element Using Deflation
Abstract:
This paper presents a deflation technique to improve the convergence of finite element (FE) analyses with infinite elements. In FE analyses of electromagnetic fields, large air regions must be discretized into FE meshes. This leads to increases in computational time. The infinite element in which electromagnetic fields in air region are accurately expressed has been introduced in order to solve this problem. However, when using the infinite element, convergence of iterative liner solvers deteriorates because the condition number of FE matrices becomes large. In this paper, a deflation technique to improve convergence of iterative solvers is introduced. Numerical examples show that the proposed technique can improve convergence characteristics in a magnetostatic analysis with finite and infinite elements.
Autors: Ito, H.;Watanabe, K.;Igarashi, H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 667 - 670
Publisher: IEEE
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» An Integrated High-Performance Active Rectifier for Piezoelectric Vibration Energy Harvesting Systems
Abstract:
In this letter, a highly efficient active full-bridge rectifier is proposed for piezoelectric (PE) vibration energy harvesting systems. By replacing the passive diodes with an operational amplifier-controlled active counterpart and adding a switch in parallel with the transducer, the proposed rectifier solves the dc-offset problem of the comparator-based active diode, minimizes the voltage drop along the conduction path, and extracts more power from the transducer, all of which lead to better power extraction and conversion capability. The proposed rectifier, implemented in 0.18-μm CMOS technology, shows 90% power conversion efficiency and 81 μW output power, with values corresponding to 1.5 times and 3.4 times the values for a conventional full-bridge rectifier.
Autors: Yang Sun;Nguyen Huy Hieu;Chang-Jin Jeong;Sang-Gug Lee;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Feb 2012, volume: 27, issue:2, pages: 623 - 627
Publisher: IEEE
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» An Internal Quad-Band Printed Monopole Antenna for Oval-Shaped Mobile Terminals
Abstract:
An internal quad-band printed monopole antenna for oval-shaped mobile phone is presented. The antenna occupies a compact area of the upper part of the oval-shaped ground plane. The printed monopole antenna has two branches, which generate two resonant bands centered at around 888 and 1820 MHz. The achieved bandwidth covers GSM850 (824–894 MHz), GSM900 (880–960 MHz), DCS1800 (1710–1880 MHz), and PCS1900 (1850–1990 MHz) bands. Details of the proposed antenna design and results are presented and discussed; and good agreement is obtained between the simulated and measured results.
Autors: Du, Y.;Zhao, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 683 - 686
Publisher: IEEE
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» An Investigation Into the Understanding and Skills of First-Year Electrical Engineering Students
Abstract:
In response to demands from industry and the profession for more graduates, first-year engineering numbers have grown considerably over the last decade, matched by an increasing diversity of academic backgrounds. In order to support first-year students effectively, and ensure the courses they take remain appropriately pitched, the academic preparedness of these students must be determined. Since 2007, the lecturers in the compulsory first-year Electrical and Digital Systems course at the University of Auckland (UoA), Auckland, New Zealand, have administered a short diagnostic test to determine the level of conceptual understanding of electricity and electromagnetics possessed by the incoming students. This paper presents and discusses student understanding of dc circuit theory as revealed by the diagnostic test and subsequent investigations. The evidence is indicative of both flawed conceptual models and context-triggered misapplication of fundamental rules. Parallels are drawn with the results of research conducted elsewhere, indicating the misconceptions are robust and pervasive, crossing institutional and national boundaries. Not only are concepts such as current and voltage poorly understood, but even more basic concepts such as series and parallel connections are confusing for a significant number of students. Understanding the incorrect models that underlie these basic misconceptions is the first step to correcting them. Only then can students proceed to the more advanced concepts that engineering graduates are required to master.
Autors: Smaill, C. R.;Rowe, G. B.;Godfrey, E.;Paton, R. O.;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2012, volume: 55, issue:1, pages: 29 - 35
Publisher: IEEE
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» An Investigation of Dehazing Effects on Image and Video Coding
Abstract:
This paper makes an investigation of the dehazing effects on image and video coding for surveillance systems. The goal is to achieve good dehazed images and videos at the receiver while sustaining low bitrates (using compression) in the transmission pipeline. At first, this paper proposes a novel method for single-image dehazing, which is used for the investigation. It operates at a faster speed than current methods and can avoid halo effects by using the median operation. We then consider the dehazing effects in compression by investigating the coding artifacts and motion estimation in cases of applying any dehazing method before or after compression. We conclude that better dehazing performance with fewer artifacts and better coding efficiency is achieved when the dehazing is applied before compression. Simulations for Joint Photographers Expert Group images in addition to subjective and objective tests with H.264 compressed sequences validate our conclusion.
Autors: Gibson, K. B.;Vo, D. T.;Nguyen, T. Q.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Feb 2012, volume: 21, issue:2, pages: 662 - 673
Publisher: IEEE
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» An investigation of lateral transistors -d.c. characteristics
Abstract:
The d.c. characteristics of the lateral transistor are examined in detail. The theory presented accounts for the observed dependences of collector and base currents on emitter-base bias. Two-dimensional geometrical effects are included, and various components of base recombination current are discussed separately. For the experimental devices studied in this work, high-level injection in the base was found to be chiefly responsible for the decreasing current gain at high currents.
Autors: Sunlin Chou
Appeared in: Solid-State Electronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» An LLCL Power Filter for Single-Phase Grid-Tied Inverter
Abstract:
This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency. Particularly, it can attenuate the switching-frequency current ripple components much better than an LCL filter, leading to a decrease in the total inductance and volume. Furthermore, by decreasing the inductance of a grid-side inductor, it raises the characteristic resonance frequency, which is beneficial to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter prototype.
Autors: Weimin Wu;Yuanbin He;Blaabjerg, F.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Feb 2012, volume: 27, issue:2, pages: 782 - 789
Publisher: IEEE
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» An Online Adaptive Cooperation Scheme for Spectrum Sensing Based on a Second-Order Statistical Method
Abstract:
Spectrum sensing is one of the most important features of cognitive radio (CR) systems. Although spectrum sensing can be performed by a single CR, it is shown in the literature that cooperative techniques, including multiple CRs/sensors, improve the performance and reliability of spectrum sensing. Existing cooperation techniques usually assume a static communication scenario between the unknown source and sensors along with a fixed propagation environment class. In this paper, an online adaptive cooperation scheme is proposed for spectrum sensing to maintain the level of sensing reliability and performance under changing channel and environmental conditions. Each cooperating sensor analyzes second-order statistics of the received signal, which undergoes both correlated fast and slow fading. Autocorrelation estimation data from sensors are fused together by an adaptive weighted linear combination at the fusion center. Weight update operation is performed online through the use of orthogonal projection onto convex sets. Numerical results show that the performance of the proposed scheme is maintained for dynamically changing characteristics of the channel between an unknown source and sensors, even under different physical propagation environments. In addition, it is shown that the proposed cooperative scheme, which is based on second-order detectors, yields better results compared with the same fusion mechanism that is based on conventional energy detectors.
Autors: Yarkan, S.;Toreyin, B. U.;Qaraqe, K. A.;Cetin, A. E.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2012, volume: 61, issue:2, pages: 675 - 686
Publisher: IEEE
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» An Open-Source Path Computation Element (PCE) Emulator: Design, Implementation, and Performance
Abstract:
In this paper, we present the first open-source path computation element (PCE) emulator along with its key design and implementation features. The PCE is a network control and management entity that can be utilized to perform optimal path computations with multiple constraints in carrier-grade transport networks. The presented architecture incorporates all elements of the standardized PCE framework and is scalable in the number of requests and size of topologies served as well as path computation algorithm complexity. Given the diversity in current control and management practices of carrier-grade transport networks, we also identify key features that are necessary for innovation within the PCE framework, including flexible topology description and update mechanisms, extensible protocol and state machine definitions, and fully programmable path computation. We incorporate all these features in our design and implementation. This work bridges an important gap between network engineering, software system design, and algorithmic studies and shows that deploying a PCE system as such is not only feasible but also well performing in a range of network scenarios from IP/multiprotocol label switching to wavelength-division multiplexing networks.
Autors: Chamania, M.;Drogon, M.;Jukan, A.;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2012, volume: 30, issue:4, pages: 414 - 426
Publisher: IEEE
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» An optimisation-based seasonal sugarcane harvest scheduling decision support system for commercial growers in South Africa
Abstract:

Highlights

? We developed a decision support system for sugarcane harvest scheduling. ? The core of the system was based on regression analysis and optimisation. ? The system was developed and tested over a period of 2 years. ? We received grower approval of the system. ? The system was proven to be better than random schedules at replicating growers.


Autors: An ongoing sugarcane decision support research project in South Africa is aimed at developing a decision support system capable of providing computerised support to those charged with the task of scheduling sugarcane harvesting operations in South Af
Appeared in: Computers and Electronics in Agriculture
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» An Ultra Low-Power CMOS Transceiver Using Various Low-Power Techniques for LR-WPAN Applications
Abstract:
In this work, we implemented and evaluated a fully integrated 2.4 GHz CMOS RF transceiver using various low-power techniques for low-rate wireless personal area network (IEEE 802.15.4 LR_WPAN) applications in 0.18- m CMOS technology. In order to achieve an ultra low power consumption, a RC oscillator (OSC) operating below 200 nA, a regulator operating below 200 nA for sleep mode, a quick start block for the crystal oscillator, a passive wake-up circuit, a LNA with negative gm, a current bleeding mixer, and a stacked VCO are all implemented in this transceiver. The transmitter achieves less than 5.0% error vector magnitude (EVM) at 5 dBm output, and the receiver sensitivity is dBm. The sensitivity of the wake-up block is dBm. The current consumption is below 14.3 mA for the data receiving mode, 16.7 mA for the transmitter, and less than 600 nA for the sleep mode from a 1.8 V power supply. That is considered to be lowest for the 2.4 GHz CMOS ZigBee transceiver compared to open literature results.
Autors: Kwon, Y.-I.;Park, S.-G.;Park, T. J.;Cho, K. S.;Lee, H.-Y.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2012, volume: 59, issue:2, pages: 324 - 336
Publisher: IEEE
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» An Ultra-Compact, Linearly-Controlled Variable Phase Shifter Designed With a Novel RC Poly-Phase Filter
Abstract:
This paper proposes a new vector-sum type variable-phase shifter (VPS) topology for predistorting the phase of a modulated signal for an analog-predistortion power amplifier system. It has a continuous linear-in-degree control curve over a 90 phase-control range and has the smallest size among all those proposed CMOS works. The phase shifter utilizes an improved RC poly-phase filter to generate in-phase and quadrature-phase vectors. It uses fewer RC components but has a wider phase-splitting bandwidth than traditional RC filters, reducing the loss and size of the overall VPS. Specially-designed control circuits give the shifter a linear phase-control capability, minimizing the gain variation over the phase-control range. The phase shifter, optimized for WCDMA applications, has been fabricated in a standard 0.18- m CMOS process. The area of the phase shifter core is 0.063 mm . The measured operation frequency is from 1 to 2.1 GHz, which is an overlap of its 3-dB cutoff frequency and bandwidth of a 90 phase-control range. Within the bandwidth, this phase shifter displays a linear control curve with phase errors of less than over a 70 tuning range, making it suitable for accurate AM-PM error compensation.
Autors: Huang, Y.-Y.;Jeon, H.;Yoon, Y.;Woo, W.;Lee, C.-H.;Kenney, J. S.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2012, volume: 60, issue:2, pages: 301 - 310
Publisher: IEEE
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» An Ultra-Low-Voltage and Low-Power 2 Subharmonic Downconverter Mixer
Abstract:
An 8.6 GHz 2 subharmonic mixer with complementary current-reuse to enable ultra-low-voltage and low-power operation is presented. The RF transconductance stage of the mixer uses inductive source degeneration and the mixing core uses four transistors that are driven by a quadrature LO signal. A Volterra series analysis is carried out to determine the optimal gate biasing of the transconductor circuit to maximize the third-order intercept point performance of the RF stage and of the entire mixer. Experimental results show that the mixer has a conversion gain of 6.0 dB and an of 8.0 dBm. The entire circuit draws 0.6 mW from a 0.6 V supply. The chip was fabricated in a standard 130 nm CMOS process.
Autors: He, S.;Saavedra, C. E.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2012, volume: 60, issue:2, pages: 311 - 317
Publisher: IEEE
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» An Ultrasonic Scanning Technique for In-Situ `Bowing' Measurement of Prototype Fast Breeder Reactor Fuel Sub-Assembly
Abstract:
An ultrasonic under-sodium scanner has been developed for deployment in Prototype Fast Breeder Reactor (PFBR) which is in advanced stage of construction at Kalpakkam, India. Its purpose is to scan the above-core plenum for detection, if any, of displacement of sub-assemblies. During its burn-up in the reactor, the head of a Fuel Sub-Assembly (FSA) may undergo a lateral shift from its original position (called `bowing') due to the fast neutron induced damage on its structural material. A simple scanning technique has been developed for measuring the extent of bowing in-situ. This paper describes a PC-controlled mock-up of the scanner used to implement the scanning technique and the results obtained of scanning a mock-up FSA head under water. The details of the liquid-sodium proof transducer developed for use in the PFBR scanner and its performance are also discussed.
Autors: Swaminathan, K.;Asokane, C.;Sylvia, J. I.;Kalyanasundaram, P.;Swaminathan, P.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2012, volume: 59, issue:1, pages: 174 - 181
Publisher: IEEE
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» Analog circuit sizing via swarm intelligence
Abstract:
Together with the increase in electronic circuit complexity, the design and optimization processes have to be automated with high accuracy. Predicting and improving the design quality in terms of performance, robustness and cost is the central concern of electronic design automation. Generally, optimization is a very difficult and time consuming task including many conflicting criteria and a wide range of design parameters. Particle swarm optimization (PSO) was introduced as an efficient method for exploring the search space and handling constrained optimization problems. In this work, PSO has been utilized for accommodating required functionalities and performance specifications considering optimal sizing of analog integrated circuits with high optimization ability in short computational time. PSO based design results are verified with SPICE simulations and compared to previous studies.
Autors: R.A. Vural, T. Yildirim
Appeared in: AEU - International Journal of Electronics and Communications
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Analog Product Codes Decodable by Linear Programming
Abstract:
In this paper, we present a new analog error correcting coding scheme for real valued signals that are corrupted by impulsive noise. This product code improves Donoho's deterministic construction by using a probabilistic approach. More specifically, our construction corrects more errors than the Donoho matrices by allowing a vanishingly small probability of error (with the increase in block size). The problem of decoding the long block code is decoupled into two sets of parallel Linear Programming problems. This leads to a significant reduction in decoding complexity as compared to one-step Linear Programming decoding.
Autors: Zanko, A.;Leshem, A.;Zehavi, E.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2012, volume: 58, issue:2, pages: 509 - 518
Publisher: IEEE
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» Analysis and Design of a Bidirectional Isolated DC–DC Converter for Fuel Cells and Supercapacitors Hybrid System
Abstract:
Electrical power systems in future uninterruptible power supplies or electrical vehicles may employ hybrid energy sources, such as fuel cells and supercapacitors. It will be necessary to efficiently draw the energy from these two sources as well as recharge the energy storage elements by the dc bus. In this paper, a bidirectional isolated dc-dc converter controlled by phase-shift angle and duty cycle for the fuel-cell hybrid energy system is analyzed and designed. The proposed topology minimizes the number of switches and their associated gate driver components by using two high-frequency transformers that combine a half-bridge circuit and a full-bridge circuit together on the primary side. The voltage doubler circuit is employed on the secondary side. The current-fed input can limit the input current ripple that is favorable for fuel cells. The parasitic capacitance of the switches is used for zero voltage switching (ZVS). Moreover, a phase-shift and duty-cycle modulation method is utilized to control the bidirectional power flow flexibly and it also makes the converter operate under a quasi-optimal condition over a wide input voltage range. This paper describes the operation principle of the proposed converter, the ZVS conditions, and the quasi-optimal design in depth. The design guidelines and considerations regarding the transformers and other key components are given. Finally, a 1-kW 30~50-V-input 400-V-output laboratory prototype operating at 100-kHz switching frequency is built and tested to verify the effectiveness of the presented converter.
Autors: Zhe Zhang;Ziwei Ouyang;Thomsen, O.C.;Andersen, M.A.E.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Feb 2012, volume: 27, issue:2, pages: 848 - 859
Publisher: IEEE
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» Analysis and Design of Active NPC (ANPC) Inverters for Fault-Tolerant Operation of High-Power Electrical Drives
Abstract:
Compared with neutral-point-clamped (NPC) inverters, active NPC (ANPC) inverters enable a substantially increased output power and an improved performance at zero speed for high-power electrical drives. This paper analyzes the operation of three-level (3L) ANPC inverters under device failure conditions, and proposes the fault-tolerant strategies to enable continuous operating of the inverters and drive systems under single and multiple device open- and short-failure conditions. Therefore, the reliability and robustness of the electrical drives are greatly improved. Moreover, the proposed solution adds no additional components to standard 3L-ANPC inverters; thus, the cost for robust operation of drives is lower. Simulation and experiment results are provided for verification. Furthermore, a comprehensive comparison for the reliability function of 3L-ANPC and 3L-NPC inverters is presented. The results show that 3L-ANPC inverters have higher reliability than 3L-NPC inverters when a derating is allowed for the drive system under fault-tolerant operation. If a derated operation is not allowed, the two inverters have similar reliability for device open failure, while 3L-NPC inverters have higher reliability than 3L-ANPC inverters for device short failure.
Autors: Jun Li;Huang, A.Q.;Zhigang Liang;Bhattacharya, S.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Feb 2012, volume: 27, issue:2, pages: 519 - 533
Publisher: IEEE
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» Analysis and Design of Slotted Tubular Linear Actuator for the Eco-Pedal System of a Vehicle
Abstract:
This paper presents the design and analysis of a linear actuator for vehicle Eco-Pedal system. To prevent the excessive gas consumption for fuel-efficient vehicle the electric actuator produces a counter force to the vehicle's pedal to be pressed stiffly. Major performances of the actuator are required such as a high force density and a low detent force. In this paper, the analysis and design technique of the actuator thrust is based on an analytical method, and the advisability of the design result is verified with both the result of the experiment and the result of the finite element method.
Autors: Kim, Y.-K.;Gu, B.-G.;Jung, I.-S.;Won, S.-H.;Hur, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 939 - 942
Publisher: IEEE
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» Analysis and optimization of lateral thin-film Silicon-on-insulator (SOI) MOSFET transistors
Abstract:
This paper is focused on the analysis and optimization of power N-type LDMOS (LDNMOS) transistors (VBR > 120 V) with the purpose of being integrated in a new generation of Smart-Power technology based upon a 0.18 ?m SOI-CMOS technology. The influence of some important design parameters such as the shallow trench isolation (STI) length (LSTI), the N-well doping profile and the relative position of the N-well mask to the STI block are analyzed in terms of voltage capability (VBR), specific on-state resistance (Ron-sp) and electrical safe-operating area (SOA) by means of Technology Computer-Aided Design (TCAD) numerical simulations. The evolution of the measured and simulatedVBRas a function of the substrate (handle wafer) voltage (HWV) gives good physical insight of the optimal LDNMOS drift region design configuration. LDNMOS transistors with STI lengths partially covering the drift region length leads to better combined action ofRon-sp/VBRtrade-off and electrical SOA results.
Autors: I. Cortés, G. Toulon, F. Morancho, E. Hugonnard-Bruyere, B. Villard, ...
Appeared in: Microelectronics Reliability
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Analysis methods of sulfide and sulfoxide compounds in mineral insulating oil for diagnosis on electrostatic charging of power transformers
Abstract:
Analysis methods of sulfide and sulfoxide compounds in mineral insulating oil are developed to diagnose an electrostatic charging of a power transformer due to oil circulation. When sulfonium ions are generated from sulfide compounds via sulfoxide compounds, they tend to increase an electrostatic charging tendency (ECT) in the oil, which causes the electrostatic charging of a power transformer. Selective analysis methods for sulfide and sulfoxide compounds are developed by combining solid extractions with a gas chromatography because it is difficult to detect sulfonium ions directly. Sulfide compounds are selectively extracted from oils by palladium chlorideimpregnated silica gel while sulfoxide compounds are extracted by silica gels. The effect of sulfide on the dielectric dissipation factor (DDF), which relates to an ECT, of commercial oil is investigated by removing sulfide compounds with palladium chlorideimpregnated silica gel. The DDF of untreated oil increases at the beginning of heating with air while changes in the DDF are minimal for treated oils.
Autors: Okabe, S.;Kohtoh, M.;Toyama, S.;Amimoto, T.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 181 - 187
Publisher: IEEE
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» Analysis of Cellular Antennas for Hearing-Aid Compatible Mobile Phones
Abstract:
The Federal Communications Commission ensures that a certain portion of mobile phones sold in the United States are hearing-aid compatible. When the phone is tested for compatibility, the spatial near-field distribution generated by the phone in the vicinity of its acoustic output is used as the assessment criteria. Certain types of cellular antennas are known partial solutions for the radio-frequency related challenges of hearing-aid compatibility. We briefly summarize the characteristics of these antennas, introducing a new figure-of-merit based on a radiating and balanced mode analysis. We then introduce a class of dual-feed, dual-radiator cellular antennas as promising new candidates for enabling hearing-aid compatibility. It is shown that the proposed antennas, utilized with proper matching circuits, have inherent characteristics that make them attractive solutions for hearing-aid compatible mobile phones.
Autors: Ikonen, P. M. T.;Boyle, K. R.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2012, volume: 60, issue:2, pages: 1043 - 1052
Publisher: IEEE
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» Analysis of coherent optical filter and correlator systems using pixellated spatial light modulators
Abstract:
The authors analyse the optical performance of 4f coherent optical filtering systems using pixellated spatial light modulator devices for the input and filter planes. The performance of such systems is frequently analysed using oversampling fast Fourier transform (FFT) techniques which we show to require large oversampling factors (and hence complexity) to fully take into account the optical field distribution across each individual pixel of the filter plane and thus provide improved accuracy. The authors proposed two methods by which they obtain a piecewise series expansion of the optical field across each pixel using FFT techniques and demonstrate that these methods show faster convergence with increasing complexity and require less memory storage to compute than the oversampling FFT techniques usually used. If the output plane intensity is only required at a few points, such as when optimisation techniques are being used to design the filter, the authors present a third method which also results in improved accuracy but with no penalty in speed.
Autors: Neil, M.A.A.;Manivannan, N.;
Appeared in: IET Optoelectronics
Publication date: Feb 2012, volume: 6, issue:1, pages: 43 - 51
Publisher: IEEE
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» Analysis of electrical tree propagation through glass fiber barrier
Abstract:
In this paper, two sets of samples are examined, one for plain polyester resin and the other for glass fiber composite. In both sets, a pin to plane configuration is used to grow electrical trees around the barrier area. Several patterns of tree propagation are investigated. Due to the effect of barrier to hinder the growth, tree shape and growth rate are influenced at both sides of the barrier. The structure of barrier and its adhesion to the surrounding resin are the main factors to be considered for selection of the barrier to prolong the lifetime of composite. Horizontal growth relationship with penetration delay is studied. This delay is aggravated by the lack of energy of horizontally grown leading branches. A mechanism, explaining the delay of a leading branch to penetrate the barrier, is introduced. The mechanical stresses determined by de-bonding, deformation and carbonization in the interfacial area are studied. Finally, the results of this work are very important for breakdown analysis, life assessment and improvement of composite insulation and power cables.
Autors: Abderrazzaq, M.H.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 305 - 311
Publisher: IEEE
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» Analysis of Femto Base Station Network Deployment
Abstract:
In this paper, assurance of proper downlink outage probability, which is a design criterion based on feasible femto base station (BS) density, is analyzed. Considering femto BS deployment, a 3-D Poisson model of random spatial distribution and stochastic geometry are used. From the study, a closed form of feasible femto BS density will be identified. The analysis results not only can be used to predict the performance of various femto BS deployment scenarios but also can be used as a design criterion for resource control mechanism designs.
Autors: Tseng, Y.;Huang, C.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2012, volume: 61, issue:2, pages: 748 - 757
Publisher: IEEE
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» Analysis of Gouy phase shift for optimizing terahertz air-biased-coherent-detection
Abstract:
Terahertz (THz) air-biased-coherent-detection (ABCD) uses a local oscillator to enhance THz-wave detection sensitivity by mixing an optical field, a THz field, and a biased electric field (local oscillator) in air. The width of the electrodes providing the local oscillator, the longitudinal distribution of the optical and THz waves, both play important roles in the overall detection sensitivity. By analyzing the effect of the Gouy phase shift on the electric field distribution at the mixing location, we determine the optimal electrode width and observe an enhancement of the detection efficiency by a factor of two relative to the traditional THz-ABCD system using thin-wire electrodes.
Autors: He, Huanyu;Zhang, X.-C.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:6, pages: 061105 - 061105-4
Publisher: IEEE
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» Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function
Abstract:
In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H- production on the PG surface. We have developed a neutral (H2 molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H2 and H transport in a NIFS-R&D ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eV < E < 30 eV is important for the dissociation rate of H2 molecules by the electron impact collision and the resultant H atom flux on the PG.
Autors: Koga, S.;Shibata, T.;Terasaki, R.;Kameyama, N.;Hatayama, A.;Bacal, M.;Tsumori, K.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02A717 - 02A717-4
Publisher: IEEE
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» Analysis of Modulated Multivariate Oscillations
Abstract:
The concept of a common modulated oscillation spanning multiple time series is formalized, a method for the recovery of such a signal from potentially noisy observations is proposed, and the time-varying bias properties of the recovery method are derived. The method, an extension of wavelet ridge analysis to the multivariate case, identifies the common oscillation by seeking, at each point in time, a frequency for which a bandpassed version of the signal obtains a local maximum in power. The lowest-order bias is shown to involve a quantity, termed the instantaneous curvature, which measures the strength of local quadratic modulation of the signal after demodulation by the common oscillation frequency. The bias can be made to be small if the analysis filter, or wavelet, can be chosen such that the signal's instantaneous curvature changes little over the filter time scale. An application is presented to the detection of vortex motions in a set of freely drifting oceanographic instruments tracking the ocean currents.
Autors: Lilly, J. M.;Olhede, S. C.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2012, volume: 60, issue:2, pages: 600 - 612
Publisher: IEEE
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» Analysis of Novel Brushless DC Motors Made of Soft Magnetic Composite Core
Abstract:
The soft magnetic composite material has merits of the low eddy current loss and the flexible machine design and assembly. This paper develops new brushless DC motors made of this material. The shape of the developed motor is similar to a hybrid type stepping motor, which utilizes three-dimensional isotropic ferromagnetic behavior, and the motor has hollows in the stator main teeth in order to reduce the copper loss and the motor size. This paper clarifies the steady state characteristics of the motors using the three-dimensional finite element analysis. The motor efficiency becomes larger than that of the conventional laminated core, when the rotating speed is high, or if the motor size becomes large.
Autors: Ishikawa, T.;Takahashi, K.;Ho, Q. V.;Matsunami, M.;Kurita, N.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 971 - 974
Publisher: IEEE
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» Analysis of OFDM over Nakagami-m Fading with Nonuniform Phase Distributions
Abstract:
This paper presents a new mathematical analysis for the performance of orthogonal frequency-division multiplexed (OFDM) signals over multipath Nakagami-m fading channels. In contrast to the previous research, this paper focuses on the effects of the nonuniform phase distribution on the error rate performance. A unified expression is derived for the moment generating function (MGF) of the frequency-domain channel gains on Nakagami-m channels with nonuniform phase distributions. Classical MGF methods can then be straightforwardly employed to obtain accurate error rates expressions for different modulation and diversity formats.
Autors: Hamdi, Khairi Ashour;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2012, volume: 11, issue:2, pages: 488 - 492
Publisher: IEEE
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» Analysis of Optimal Reconfiguration of Shipboard Power Systems
Abstract:
In power system reconfiguration, the status (ON/OFF) of switches are optimized such that maximum power is delivered to loads after the occurrence of a fault. The optimized reconfiguration is achieved by prioritizing power delivered to vital loads over semi-vital and nonvital loads. The formulation presented in this paper considers a new balanced hybrid (AC and DC) shipboard power system (SPS). Analysis of the nonconvex reconfiguration formulation is done by an appropriate nonconvex solver and by convex approximation. Unlike the nonconvex solution that is based on branch-and-bound methods, convex approximation significantly reduces complexity. It is shown that for the hybrid SPS reconfiguration problem, low complexity convex approximations are effective in finding optimal solutions. Cumulative distribution function (CDF) of the power delivered to loads is presented to showcase the system robustness against random fault scenarios. A combined objective of maximizing power delivery and minimizing the number of switching actions is included in the analysis. Tradeoff between power delivered and number of switching operations after reconfiguration has been discussed at steady state. A separate analysis is also included to observe the intermediate dynamic switch states while the reconfiguration is in progress to capture the trade-off more prominently.
Autors: Bose, S.;Pal, S.;Natarajan, B.;Scoglio, C. M.;Das, S.;Schulz, N. N.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 189 - 197
Publisher: IEEE
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» Analysis of Radiation Characteristics of Conformal Microstrip Arrays Using Adaptive Integral Method
Abstract:
A new surface integral equation formulation is presented for characterizing electromagnetic radiation by conformal microstrip arrays on finite curved bodies of arbitrary shapes. The surface equivalence principle is used to reduce the original problem to two equivalent problems, one for the external medium and another for the internal medium. Electric field integral equations are applied to the conducting surfaces, and weighted sums of the field integral equations corresponding to the external and internal dielectric regions with appropriate weighted coefficients are applied to the dielectric interface. The integral equations are solved via the method of moments (MoM) procedure, to which the memory requirement and computational complexity pertinent is reduced by employing the adaptive integral method (AIM). Numerical results are presented to demonstrate the validity and accuracy of the method.
Autors: Zhao, W.-J.;Li, L.-W.;Li, E.-P.;Xiao, K.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2012, volume: 60, issue:2, pages: 1176 - 1181
Publisher: IEEE
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» Analysis of Search Decision Making Using Probabilistic Search Strategies
Abstract:
In this paper, we propose a formulation of the spatial search problem, where a mobile searching agent seeks to locate a stationary target in a given search region or declare that the target is absent. The objective is to minimize the expected time until this search decision of target’s presence (and location) or absence is made. Bayesian update expressions for the integration of observations, including false-positive and false-negative detections, are derived to facilitate both theoretical and numerical analyses of various computationally efficient (semi-)adaptive search strategies. Closed-form expressions for the search decision evolution and analytic bounds on the expected time to decision are provided under assumptions on search environment and/or sensor characteristics. Simulation studies validate the probabilistic search formulation and comparatively demonstrate the effectiveness of the proposed search strategies.
Autors: Chung , T. H.;Burdick , J. W.;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2012, volume: 28, issue:1, pages: 132 - 144
Publisher: IEEE
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» Analysis of space charge formation in LDPE in the presence of crosslinking byproducts
Abstract:
Cross-linking byproducts are suspected to be the main contributing factor in space charge formation observed in XLPE. To investigate the mechanism behind this phenomenon, low density polyethylene was soaked into three main crosslinking byproducts, acetophenone, α- methylstyrene and cumyl alcohol, and space charge measurements were performed using the Pulse Electroacoustic technique (PEA). It has been found that soaking LDPE in cumyl alcohol introduces more charges into the system, with homocharges and heterocharges accumulating within the sample compared to the additive free sample. In contrast, α- methylstyrene and acetophenone reduce the amount of accumulated charges. In terms of charge decay, all three byproducts enhance the decay process in the insulator. Further investigations were conducted in conditions where two byproducts are present in a sample. The results shows that acetophenone is a dominant byproduct in determining the charge density patter built up during the charging process, whilst the rate of charge decay is observed to be high in the presence of α-methylstyrene in the sample
Autors: Hussin, N.;Chen, G.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 126 - 133
Publisher: IEEE
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» Analysis of Temperature Distribution in Power Converter for Switched Reluctance Motor Drive
Abstract:
This paper presents a thermal model of power converter used in switched reluctance motor (SRM) drive under constant convective heat transfer. The distribution of the system temperature rise is derived based on the average heating power measured as SRM is running steadily, and the temperature rise is independent of ambient temperature which is proved in this paper. The accuracy of the thermal model is verified by comparing experimental data with the results derived from finite-element method (FEM) simulation. Furthermore, this study achieves optimization in heat sink geometry and the placement of power components with the present model.
Autors: Chen, H.;Xu, Y.;Iu, H. H.-C.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 991 - 994
Publisher: IEEE
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» Analysis of temporal jitter in a copper vapor laser system
Abstract:
Temporal jitter in a magnetic pulse compression based copper vapor laser (CVL) system is analyzed by considering ripple present in the input dc power supply and ripple present in the magnetic core resetting power supply. It is shown that the jitter is a function of the ratio of operating voltage to the designed voltage, percentage ripple, and the total propagation delay of the magnetic pulse compression circuit. Experimental results from a CVL system operating at a repetition rate of 9 kHz are presented.
Autors: Kumar, D. Durga Praveen;Gantayet, L. M.;Singh, Sunita;Rawat, A. S.;Rana, Paramjit;V, Rajasree;Agarwalla, Sandeep K.;Chakravarthy, D. P.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 025105 - 025105-5
Publisher: IEEE
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» Analysis of the ramp compensation approaches to improve stability for buck converters with constant on-time control
Abstract:
This study presents new sub-harmonic analysis for constant on-time control with ramp compensation. Ramp compensation of constant on-time control can be fulfilled by either directly feeding back a sensed inductor current signal as an internal ramp or using an external compensation ramp with a fixed slope during the off time and a fixed level during the on time. Based on the inductor current information and the charge variations of the output capacitor, the sub-harmonic mechanism is analysed in detail for constant on-time control with ramp compensation. Also, as well as explaining the benefits of using sensed inductor current signal, the effects of the sensed inductor current signal and the external compensation ramp are quantitatively compared. It is revealed that the external compensation ramp requires a lower ramp to avoid sub-harmonic oscillation. Based on the detailed theoretical analysis, experimental results demonstrate the stability criterion for constant on-time control with ramp compensation.
Autors: Qian, T.;Wu, W.;
Appeared in: IET Power Electronics
Publication date: Feb 2012, volume: 5, issue:2, pages: 196 - 204
Publisher: IEEE
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» Analysis of the stress response of yeastSaccharomyces cerevisiaetoward pulsed electric field
Abstract:

Highlights

? The stress response of the yeast toward a pulsed electric field was investigated. ? No heat stress was detected in the PEF-treated yeast cells in our study. ? The PEF treatment induced the expression of the oxidation stress response genes. ? The glutathione played an important role in the stress resistance toward PEF.


Autors: This study investigated the stress response of the yeastSaccharomyces cerevisiaetoward a pulsed electric field (PEF). Changes in the transcription level of heat stress response geneHSP104and oxidation stress response genesGSH1,GLR1,SOD1andSOD2were an
Appeared in: Journal of Electrostatics
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Analysis of Torque Pulsation Considering Interior Permanent Magnet Rotor Rib Shape Using Response Surface Methodology
Abstract:
This paper presents an analysis of torque pulsation with respect to the rotor rib shape in an interior permanent magnet motors (IPMs) and the type of magnet materials. The effects of three parameters, the angle and length of the flux barrier and the residual flux density of the PM, are studied using the response surface methodology. Finite element analysis is used to verify that torque ripple reduction affects the optimal rotor rib shape in rare earth and ferrite PMs. In addition, the optimal barrier shapes for each magnet material are identified and compared.
Autors: Im, Y.-H.;Hwang, S.-I.;Jang, S.-M.;Choi, J.-Y.;Choi, J.-H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 979 - 982
Publisher: IEEE
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» Analysis of Transient Electric Field and Charge Density of Converter Transformer Under Polarity Reversal Voltage
Abstract:
A finite element method, which directly uses the node electric scalar potentials and node charge densities as variables, is used to predict the electric field and charge density distributions under polarity reversal (PR) voltage. The penalty method is adopted to impose the Dirichlet boundary values and the Crank–Nicolson (C-N) algorithm is then used to solve the transient equation. The surface node charge densities on the perfectly conducting boundaries are adopted to accurately obtain the normal electric field strengths. The method is tested by a two layer coaxial model and applied to analyze the linear and nonlinear transient electric fields and boundary charge densities of a 500 kV converter transformer under PR voltage.
Autors: Liu, G.;Li, L.;Ji, F.;Li, W.;Sun, Y.;Li, B.;Li, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 275 - 278
Publisher: IEEE
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» Analysis of Wireless Energy Transmission for Implantable Device Based on Coupled Magnetic Resonance
Abstract:
WiTricity is a new technology for transmitting energy wirelessly via resonant coupling in the non-radiative near-field. In this paper, design of energy transmission system for implantable devices base on WiTricity is performed, the influence of system structural parameters on the energy transmission efficiency is investigated, the relations between the energy transfer efficiency with the transmission distance are analyzed, and also the frequency values of resonant coils with different parameters have been figured out.
Autors: Yin, N.;Xu, G.;Yang, Q.;Zhao, J.;Yang, X.;Jin, J.;Fu, W.;Sun, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 723 - 726
Publisher: IEEE
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» Analysis, Design, and Experimentation of a Closed-Loop Metal Halide Lamp Electronic Ballast
Abstract:
This paper presents the analysis, design, and experimentation of a closed-loop metal halide (MH) lamp ballast, which supplies the lamp with a low-frequency square waveform. First, a discussion related to the lamp parameter that should be regulated (power or current) is presented, since this issue has not been well addressed in the previous literature. Experiments demonstrated that lamp current can be chosen to be kept constant during lamp life, because it can attenuate the effect of lumen depreciation with lamp ageing, and, on the other hand, the lamp power does not reach overrated values during lamp life. Second, in order to analyze the open-loop characteristic and design a suitable controller for the closed-loop operation, a dynamic model of the lamp-ballast system is developed. Therefore, a phase-lag controller is proposed to minimize the steady-state error and provide a phase margin of about 80 (fully stable system). Experimental results using a flyback-based ballast supplying 35-W MH lamps with 100, 2500, and 5000 burning hours are presented to validate the theoretical analysis. It is demonstrated that the lamp current is kept constant at rated value (0.42 A) within the entire input voltage range. The time response of the complete closed-loop system is about 5 ms.
Autors: Dalla Costa, M. A.;Kirsten, A. L.;Alonso, J. M.;Garcia, J.;Gacio, D.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2012, volume: 48, issue:1, pages: 28 - 36
Publisher: IEEE
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» Analysis, modeling, identification and control of pancake DC torque motors: Application to automobile air path actuators
Abstract:
This article is focused on the working, modeling and control of pancake DC torque motors, used in automobile engine air path actuators. These motors, with a limited working angle, provide high torque which makes them suitable for use in actuators without any additional gear reduction. The torque is a nonlinear function of the motor angle. This article provides a modeling scheme, suitable for control purposes, which takes into consideration nonlinearities arising from friction and operating temperature. Comparison between simulation and experiments shows the effectiveness of the proposed model. Second order sliding mode control has been applied to the actuators for robust control under the influence of nonlinearities and uncertainties. The effectiveness of the control algorithm has been proven experimentally.
Autors: Fayez S. Ahmed, Salah Laghrouche, Mohammed El Bagdouri
Appeared in: Mechatronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Analytical Calculation of Electrodynamic Levitation Forces in a Special-Purpose Linear Induction Motor
Abstract:
A special transverse flux linear induction motor (LIM) with salient poles and nonferromagnetic secondary in the shape of a boat has been discussed. The secondary is suspended, propelled, and stabilized by the electromagnetic field. Equations of 2-D distribution of the electromagnetic field and force equations have been derived. A small-scale prototype has been built and tested. The electrodynamic suspension force obtained from analytical calculations has been compared with measurements. The obtained results have been critically discussed.
Autors: Gieras, J. F.;Mews, J.;Splawski, P.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2012, volume: 48, issue:1, pages: 106 - 116
Publisher: IEEE
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» Analytical Design of Two-Mode Dual-Band Filters Using E-Shaped Resonators
Abstract:
This paper presents a novel analytical approach for designing two-mode dual-band bandpass filters using E-shaped resonators. Based on the dual-band coupling matrix, the dimensions of the filter configuration are extracted via even- and odd-mode analysis of E-shaped resonators. The back-to-back E-shaped resonators provide the out-of-phase property by coupling at specific edges, and it produces good selectivity for dual-band characteristics. The proposed filters have the advantage of compact size and satisfy various requirements of filter orders and coupling coefficients at both passbands. The transmission zeros are successfully introduced into each passband in both filters. To verify the proposed method, two filters are implemented using microstrip technology. The measured results exhibit two-mode dual-band bandpass responses and agree well with simulations.
Autors: Kuo, Y.-T.;Chang, C.-Y.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2012, volume: 60, issue:2, pages: 250 - 260
Publisher: IEEE
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» Analytical Prediction of Cogging Torque for Spoke Type Permanent Magnet Machines
Abstract:
A generalized analytical field solution by conformal transformation is presented for calculation of no-load magnetic field distribution in the slot-less and slotted air gap of spoke-type permanent magnet (PM) machines. These analytical field solutions are used to predict the cogging torque of spoke-type PM motors. The computed cogging torque using the proposed method is compared with the results from 2D finite element analysis (FEA) in three application examples.
Autors: Lin, D.;Zhou, P.;Lu, C.;Lin, S.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 1035 - 1038
Publisher: IEEE
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» Analytical solution for the photocurrent of solar cells with internal reflection
Abstract:
A 1 D analytical photocurrent expression of the base of a crystal silicon solar cell is derived for both the planar and the textured surfaces, with consideration of internal reflection. This expression separates the internal reflection effect from other effects in the photocurrent expression. The influences on the photocurrent by different light flux passes reflected in the wafer are also distinguished. With this analytical expression, an abnormal internal quantum efficiency (IQE) drop in the textured surface scheme as compared to the planar surface scheme from 0.4 μm to 0.6 μm is observed and explained. The numerical IQE result obtained by PC1 D is also used to confirm the correctness of this analytical solution. Finally, optimization of the local back surface field (LBSF) is performed using this analytical solution, without the help of any numerical software.
Autors: Wen, Zhenli;Wang, Wenjing;Zhou, Chunlan;Zhang, Jun;
Appeared in: Journal of Applied Physics
Publication date: Feb 2012, volume: 111, issue:3, pages: 034502 - 034502-8
Publisher: IEEE
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» Analyzing Potential Throughput Improvement of Power- and Thermal-Constrained Multicore Processors by Exploiting DVFS and PCPG
Abstract:
Process variability from a range of sources is growing as technology is scaled below 65 nm, increasing variations of transistor delay and leakage current both within a die and across dies. This, in turn, negatively impacts maximum operating frequency and total power consumption of processors. Meanwhile, manufacturers have integrated more cores in a single die to improve the throughput of processors running highly-parallel workloads. However, many existing workloads do not have high enough parallelism to exploit multiple cores in a processor. First, in this paper, we maximize the throughput of power- and thermal-constrained multicore processors using per-core power gating and dynamic voltage/frequency scaling. When we do not have enough parallelism to effectively use all cores, we turn off some cores using per-core power gates that are already available in commercial multicore processors. This provides extra power and thermal headroom, and allows active cores to run faster through voltage/frequency scaling within power, thermal, and voltage scaling limits. Our analysis using a 32 nm predictive technology model demonstrates that jointly optimizing the number of active cores and maximum operating frequency can improve the throughput of a 16-core processor running workloads with limited parallelism by up to 14%. Second, we extend our throughput analysis and optimization to consider the impact of within-die spatial process variations that lead to considerable core-to-core frequency and leakage power variations in multicore processors. Our analysis shows that exploiting core-to-core frequency variations can improve the throughput of a 16-core processor by up to 57%.
Autors: Lee, J.;Kim, N. S.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2012, volume: 20, issue:2, pages: 225 - 235
Publisher: IEEE
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» Analyzing the Complexity and Reliability of Switch-Frequency-Reconfigurable Antennas Using Graph Models
Abstract:
This paper addresses the functional reliability and the complexity of reconfigurable antennas using graph models. The correlation between complexity and reliability for any given reconfigurable antenna is defined. Two methods are proposed to reduce failures and improve the reliability of reconfigurable antennas. The failures are caused by the reconfiguration technique or by the surrounding environment. These failure reduction methods proposed are tested and examples are given which verify these methods.
Autors: Costantine, J.;Tawk, Y.;Christodoulou, C. G.;Lyke, J. C.;De Flaviis, F.;Grau Besoli, A.;Barbin, S. E.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2012, volume: 60, issue:2, pages: 811 - 820
Publisher: IEEE
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» Analyzing the Performance of Greedy Maximal Scheduling via Local Pooling and Graph Theory
Abstract:
Efficient operation of wireless networks and switches requires using simple (and in some cases distributed) scheduling algorithms. In general, simple greedy algorithms (known as Greedy Maximal Scheduling, or GMS) are guaranteed to achieve only a fraction of the maximum possible throughput (e.g., 50% throughput in switches). However, it was recently shown that in networks in which the Local Pooling conditions are satisfied, GMS achieves 100% throughput. Moreover, in networks in which the -Local Pooling conditions hold, GMS achieves throughput. In this paper, we focus on identifying the specific network topologies that satisfy these conditions. In particular, we provide the first characterization of all the network graphs in which Local Pooling holds under primary interference constraints (in these networks, GMS achieves 100% throughput). This leads to a linear-time algorithm for identifying Local-Pooling-satisfying graphs. Moreover, by using similar graph-theoretical methods, we show that in all bipartite graphs (i.e., input-queued switches) of size up to , GMS is guaranteed to achieve 66% throughput, thereby improving upon the previously known 50% lower bound. Finally, we study the performance of GMS in interference graphs and show that in certain specific topologies, its performance could be very bad. Overall, the paper demonstrates that using graph-theoretical techniques can significantly contribute to our understanding of greedy scheduling algorithms.
Autors: Birand, B.;Chudnovsky, M.;Ries, B.;Seymour, P.;Zussman, G.;Zwols, Y.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Feb 2012, volume: 20, issue:1, pages: 163 - 176
Publisher: IEEE
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» Analyzing UV/Vis/NIR Spectra-Sputtered ZnO:Al Thin-Films III: Plasma-Parameter Dep.
Abstract:
Exact, contact-free, and nondestructive optoelectrical analysis of transparent conductive oxide layers have been discussed within this tripartite publication, in view of solar cell production. In part I and part II, two different nonnumerical theoretical models, the single-layer model and the double-layer model, were introduced. They made an extraction of approximation-free optical and electrical data from ultraviolet/visible/near-infrared spectra possible. Here, interpolation methods have been discussed, in order to compute efficiently correct and continuous streams of (complex) data. These exact data acquisition models provide deeper insights into the process-parameter dependencies of sputtered aluminum-doped zinc-oxide (ZnO:Al) thin-films upon glass substrates. Therefore, ZnO:Al thin-films were analyzed with respect to geometrical and time-dependent conditions during the sputter process in part I and with respect to gas-law dependencies in part II. Here, the influence of plasma-parameters on the physical values of the sputtered ZnO:Al thin-films has been investigated. Thence, variations of the frequency, , (the break time, ) and the power, , of the plasma-building electromagnetic fields were analyzed and discussed. Results were compared with those of the well-known Keradec/Swanepoel model. The necessity of taking both spectra—transmission and reflection spectra—into account has been shown. A noncontact, optical conductivity measurement possibility by use of UV/Vis/NIR spectroscopy has been provided. Optically measured conductivities, , were compared with those, measured electrically with a four tip measurement system.
Autors: Stadler, A.;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Feb 2012, volume: 25, issue:1, pages: 19 - 25
Publisher: IEEE
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» Anamorphic Microlens Coupling Between Tapered Amplifier and Planar PPLN Waveguide
Abstract:
We designed an aspheric anamorphic microlens for coupling between a tapered amplifier with a length of 3 mm and a planar-waveguide second-harmonic-generation device consisting of a periodically poled MgO-doped lithium niobate crystal core with a thickness of 3 . A coupling efficiency of 35% and corresponding green light generation with a power of 65 mW and conversion efficiency of 7.4% was experimentally demonstrated.
Autors: Matsuzawa, H.;Sakai, K.;Itakura, S.;Akiyama, T.;Hirano, Y.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2012, volume: 24, issue:4, pages: 306 - 308
Publisher: IEEE
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» Android app assesses age through facial recognition
Abstract:
A mobile age recognition app for Android phones recognises the approximate age of a person by using real time face recognition biometric systems online for the benefit of advertisers.
Autors: [No author name available]
Appeared in: Biometric Technology Today
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Angular distribution of plasma in the vacuum arc ion source
Abstract:
This paper presents measurements of the angular distribution of the plasma components and different charge states of metal ions generated by a MEVVA-type ion source and measured by a time-of-flight mass-spectrometer. The experiments were performed for different cathode materials (Al, Cu, and Ti) and for different parameters of the vacuum arc discharge. The results are compared with prior results reported by other authors. The influence of different discharge parameters on the angular distribution in a vacuum arc source is discussed.
Autors: Nikolaev, A. G.;Yushkov, G. Yu.;Savkin, K. P.;Oks, E. M.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02A503 - 02A503-3
Publisher: IEEE
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» Anisotropic bimodal distribution of blocking temperature with multiferroic BiFeO3 epitaxial thin films
Abstract:
Controlling BiFeO3 (BFO)/ferromagnet (FM) interfacial coupling appears crucial for electrical control of spintronic devices using this multiferroic. Here, we analyse the magnetic behaviour of exchange-biased epitaxial-BiFeO3/FM bilayers with in-plane or out-of-plane magnetic anisotropies. We report bimodal distributions of blocking temperatures similar to those of polycrystalline-antiferromagnet (AF)/FM bilayers. The high-temperature contribution depends on the FM anisotropy direction and is likely related to thermally activated depinning of domain walls in the BiFeO3 single crystal film as opposed to thermally activated reversal of spins in AF grains for polycrystalline AF. In contrast, the low-temperature contribution weakly depends on the anisotropy direction, consistent with a spin-glass origin.
Autors: Safeer, C. K.;Chamfrault, M.;Allibe, J.;Carretero, C.;Deranlot, C.;Jacquet, E.;Jacquot, J.-F.;Bibes, M.;Barthelemy, A.;Dieny, B.;Bea, H.;Baltz, V.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:7, pages: 072402 - 072402-4
Publisher: IEEE
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» Anisotropic magneto-resistance in a GaMnAs-based single impurity tunnel diode: A tight binding approach
Abstract:
Using an advanced tight-binding approach, we estimate the anisotropy of the tunnel transmission associated with the rotation of the 5/2 spin of a single Mn atom forming an acceptor state in GaAs and located near an AlGaAs tunnel barrier. Significant anisotropies in both in-plane and out-of-plane geometries are found, resulting from the combination of the large spin-orbit coupling associated with the p-d exchange interaction, cubic anisotropy of heavy-hole dispersion and the low C2v symmetry of the chemical bonds.
Autors: Nestoklon, M. O.;Krebs, O.;Jaffres, H.;Ruttala, S.;George, J.-M.;Jancu, J.-M.;Voisin, P.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:6, pages: 062403 - 062403-3
Publisher: IEEE
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» Announcement and call for papers
Abstract:
[No author name available]
Autors: Source: Microelectronics Reliability, Volume 52, Issue 3, March 2012, Pages iii
Appeared in: Microelectronics Reliability
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Anomalous behaviour of the dielectric spectroscopy response of nanocomposites
Abstract:
A study on the dielectric spectroscopy of epoxy-based nanocomposites filled with different types of particles, such as Al2O3, AlN, MgO, SiO2 and BN, is presented. The surface of the nanoparticles was modified with a silane coupling agent, in order to make them compatible with the organic host and create a system with homogeneously dispersed filler material. Morphological characterizations of individual particles and fabricated composites were performed by means of transmission and scanning electron microscopy. The present research addresses an analysis of the complex permittivity. The relative permittivity of nanocomposites shows an unusual behaviour. Introduction of a low percentage of high permittivity filler results in a decrease of the permittivity of the bulk polymer material. We propose a qualitative explanation for the reduction of the relative permittivity, compared to the reference samples. The interface layer of surface modified particles plays a more important role than the nature of the particles themselves. The immobilization caused by the surface treatment of the nanoparticles seems to be the main factor determining the relative permittivity of the composites with fillgrade below 5 wt.%. The imaginary part of the complex permittivity, which represents the dielectric losses in the system, does not change significantly with addition of nanofiller up to 5 wt.%.
Autors: Kochetov, R.;Andritsch, T.;Morshuis, P.H.F.;Smit, J.J.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 107 - 117
Publisher: IEEE
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» Anomaly of film porosity dependence on deposition rate
Abstract:
This letter reports an anomaly of film porosity dependence on deposition rate during physical vapor deposition – the porosity increases as deposition rate decreases. Using glancing angle deposition of Cu on SiO2 substrate, the authors show that the Cu film consists of well separated nanorods when the deposition rate is 1 nm/s, and that the Cu films consists of a more uniform film when the deposition rate is 6 nm/s; all other deposition conditions remain the same. This anomaly is the result of interplay among substrate non-wetting, density of Cu nuclei on the substrate, and the minimum diameter of nanorods.
Autors: Stagon, Stephen P.;Huang, Hanchen;Kevin Baldwin, J.;Misra, Amit;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:6, pages: 061601 - 061601-3
Publisher: IEEE
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» Answering the Challenges [Electrical Safety]
Abstract:
With the new year, in the context of economic, political, and social stressors, we reappraise business priorities. Budgets, growth plans, future projects, and talent recruitment are all reconsidered. As goals are adjusted, wemust justify pending investments and expenses.
Autors: Capelli-Schellpfeffer, M.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Feb 2012, volume: 18, issue:1, pages: 8 - 8
Publisher: IEEE
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» Appearance of Fractal Cord Patterns in Numerical Calculation of Magnetically Anisotropic Material
Abstract:
A cord pattern, where magnetic flux density distribution is separated into strong and weak parts like the magnetic domain, appears in magnetic anisotropic numerical calculation results. It is obtained in the strong magnetic anisotropic material. The same cord patterns are also found in the measured magnetic domain structure. Fractal structure of the cord patterns is also observed through the partial enlargement of the calculated cord patterns. The similar cord pattern resembled to the magnetically numerical calculation is also obtained in the structural numerical analysis of the metal crystal level. The fractal cord patterns emerge as a fundamental characteristic of anisotropy in numerical calculation and in physical observations.
Autors: Fujisaki, K.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 183 - 186
Publisher: IEEE
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» Apple mobile devices get facial recognition technology
Abstract:
Face.comhas released Klik, a real-time, facial recognition mobile camera app for iPhone that identifies friends, through linking with Facebook, before or after users take their photo.
Autors: [No author name available]
Appeared in: Biometric Technology Today
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Application of an artificial neural network in the use of physicochemical properties as a low cost proxy of power transformers DGA data
Abstract:
This paper is about the relationship between dissolved gases and the quality of the insulating mineral oil used in power transformers. Artificial Neural Networks are used to approach operational conditions assessment issue of the insulating oil in power transformers, which is characterized by a non-linear dynamic behavior. The operation conditions and integrity of a power transformer can be inferred by analysis of physicochemical and chromatographic (DGA ?? Dissolved Gas Analysis) profiles of the isolating oil, which allow establishing procedures for operating and maintaining the equipment. However, while the costs of physicochemical tests are less expensive, the chromatographic analysis is more informative and reliable. This work presents a method that can be used to extract chromatographic information using physicochemical analysis through Artificial Neural Networks. It??s believed that, the power utilities could improve reliability in the prediction of incipient failures at a lower cost with this method. The results show this strategy might be promising. The purpose of this work is the direct implementation of the diagnosis of incipient faults through the use of physicochemical properties without the need to make an oil chromatography.
Autors: Barbosa, F.R.;Almeida, O.M.;Braga, A.P.S.;Amora, M.A.B.;Cartaxo, S.J.M.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 239 - 246
Publisher: IEEE
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» Application of contact analysis on evaluation of breakdown strength and PD inception field strength of solid-solid interfaces
Abstract:
Interfaces between solid insulating materials are generally weak regions in electrical insulation systems, particularly if the electrical stress is applied in parallel direction. This paper presents a theoretical mechanical model for estimating average size of air-filled voids at the interface as a function of surface roughness and contact pressure. It is argued that the interfacial breakdown strength (BDS) is governed by the discharge inception stress (Ev) of the void with the most likely estimated dimension. The estimated values of the breakdown strength and partial discharge inception electric field strength (PDIE) were compared with the results from measurements using XLPE specimens with interfaces energized in longitudinal direction. The measured ratio of increase of breakdown strength was found to be in good agreement with the estimated breakdown values of the most likely interface's void. Additionally, it was found out that the air pressure inside voids was not affected by applied contact pressure. The estimated PDIE values was found to be in agreement with the measured values, in the case of rough surfaces, but not for smooth surfaces. The results indicate that the mechanical contact approach using the motif description of surface roughness may improve the understanding of the factors influencing the PDIE of electrically stressed interfaces.
Autors: Hasheminezhad, M.;Ildstad, E.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Feb 2012, volume: 19, issue:1, pages: 1 - 7
Publisher: IEEE
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» Application of Extended Element-Free Galerkin Method to Nonlinear Problem
Abstract:
A new method has been proposed for implementing the essential boundary condition and the natural one to the Element-Free Galerkin Method (EFGM). Furthermore, the performance of the proposed method has been investigated for a nonlinear Poisson problem. The results of computations show that the accuracy degradation of the numerical solution can be suppressed by using the proposed method. In addition, the convergence performance of the proposed method is more stable than that of the standard EFGM. Therefore, it might be concluded that the proposed method is useful for solving the nonlinear Poisson problem.
Autors: Saitoh, A.;Itoh, T.;Matsui, N.;Kamitani, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 487 - 490
Publisher: IEEE
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» Application of length vernier in phase coincidence detection and precision frequency measurement
Abstract:
For comparison of arbitrary frequency signals, the paper proposed two levels of length vernier based on the time-space relationship are used in three levels of phase coincidence detecting circuits to extract the phase coincidence information by proper logic calculation. The length/phase of each vernier is respectively corresponding to the accuracy and the resolution of detecting circuit. The time-space relationship is based on high-stability, high-accuracy, and high-speed of signal transmission. The method is effective to reduce the fuzzy region in the phase coincidence information and reach a higher measuring precision.
Autors: Miao, Miao;Wei, Zhou;Bin, Wang;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 024706 - 024706-4
Publisher: IEEE
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