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Electrical and Electronics Engineering publications abstract of: 12-2011 sorted by title, page: 4
» An Integrated Hybrid Silicon Multiwavelength AWG Laser
Abstract:
The first integrated multiwavelength laser based on an arrayed waveguide grating (AWG) fabricated on a silicon-on-insulator wafer is presented. It consists of Fabry–Perot cavities integrated with hybrid silicon amplifiers and an intracavity filter in the form of an AWG with a channel spacing of 360 GHz. Four-channel lasing operation is shown. Single-sided fiber-coupled output powers as high as 35 μW are measured. The device shows subnanosecond rise and fall times, and direct modulation at 1 GHz gives an open eye with an extinction ratio of 7.7 dB.
Autors: Kurczveil, G.;Heck, M. J.;Peters, J. D.;Garcia, J. M.;Spencer, D.;Bowers, J. E.;
Appeared in: IEEE Journal of Selected Topics in Quantum Electronics
Publication date: Dec 2011, volume: 17, issue:6, pages: 1521 - 1527
Publisher: IEEE
Full litterature document
 
» An Introduction to Parallel Control and Management for High-Speed Railway Systems
Abstract:
This paper introduces a framework of parallel control and management for high-speed railway systems (HRSs). First, based on multiagent modeling, an artificial HRS that is consistent with realistic operations of the actual HRS is constructed. Then, different kinds of computational experiments are performed on the artificial HRS, followed by analysis and synthesis with a case. Finally, through an interactive and parallel operation between the actual and artificial HRSs, a set of practical control and management strategies can be achieved for the actual HRS. With the primary objective of ensuring reliability and safety of HRSs, this study could enhance the quality of services and the integrated transportability with other existing modes of transportation systems to provide appropriate recommendations and strategies for forming an overall effective comprehensive transportation system.
Autors: Ning, B.;Tang, T.;Dong, H.;Wen, D.;Liu, D.;Gao, S.;Wang, J.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Dec 2011, volume: 12, issue:4, pages: 1473 - 1483
Publisher: IEEE
Full litterature document
 
» An Inverse Control-Based Set-Point Function for Steam Generator Level Control in Nuclear Power Plants
Abstract:
In this paper, the water level control problem of U-Tube Steam Generators (UTSG) of Nuclear Power Plants (NPP) is addressed through the design of an innovative set-point function; hence, the original architecture of the controller is retained for easy industry acceptance. The set-point function is synthesized based on the inverse-control theory, which is able to improve the transient performance of the UTSG level subject to power adjustments. Based on the lead time between the power adjustment decision and the actual initiation of the adjustment, the proposed set-point function can apply appropriate control on the feed-water flow rate preemptively. This preemptive control action allows the steam generator to prepare itself for the upcoming power change, i.e., steam flow-rate change, to minimize the transient effects. Detailed design and simulation processes are described based on Irving UTSG model under the entire operating power range. The simulation studies have shown that the proposed scheme is capable of keeping the water level within the admissible range effectively. When compared with a swell-based set-point function, the proposed scheme can reduce the percentage overshoot and undershoot by as much as 35.4% and 69.7%, respectively.
Autors: Akkawi, M.;Jiang, J.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Dec 2011, volume: 58, issue:6, pages: 3291 - 3304
Publisher: IEEE
Full litterature document
 
» An object-oriented model for simulating agricultural in-field machinery activities
Abstract:

Highlights

? Simulation of machinery operations for organic fertilizer application. ? Controlled traffic farming constrains machinery operational performance. ? Combined state and activity diagrams for field operations. ? A DSS for operations involving in-field transports.


Autors: Field operations planning is essential for the operational efficiency in terms of time and cost, especially in complex operations involving capacity constraints and cooperating units. In order to deal with such type of planning problems an object-ori
Appeared in: Computers and Electronics in Agriculture
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» An Opened Eye on you
Abstract:
As personal communication platforms, third-generation (3G) smartphones have become increasingly pervasive in recent years. Unfortunately, they contain more personal and confidential information and are easily compromised. Particularly, we design and implement stealthy video capturer (SVC), a new video-based spyware, on real 3G smartphones. The SVC can steal private information of users by secretly recording and transmitting videos to a third party. We present two practical applications of SVC, i.e., mobile forensics and child care. We anticipate that this article will draw extensive attention to the readers of this issue.
Autors: Xu, N.;Jia, W.;Luo, Y.;Zhang, F.;Xuan, D.;Teng, J.;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Dec 2011, volume: 6, issue:4, pages: 49 - 59
Publisher: IEEE
Full litterature document
 
» An optimization of energy addition to suppress the coalescence of the shock waves
Abstract:
A sonic boom problem has been a major inhibitor in the development of the supersonic/hypersonic vehicles flying over the ground. Pulsed energy addition upstream of a flying object is one of the active suppression methods to eliminate the sonic boom. Pulsed energy addition approach is investigated to suppress the coalescence of the shock waves and weaken the shock strength. To explore the efficiency of the proposed method, a numerical optimization methodology with off-body energy addition upstream of oblique shocks has been conducted in a Mach 2.6 flow. The dynamics of the interactions among the oblique shocks and pulsed wave were analyzed and the results from the near-field region were propagated through the Thomas code down to ground. These results suggest an essential chance to enable sonic boom reduction using an active control based on pulse shock generated by energy addition upstream of supersonic aircraft.
Autors: Y. Volkan Pehlivanoglu
Appeared in: Aerospace Science and Technology
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» An Output-Constrained Clustering Approach for the Identification of Fuzzy Systems and Fuzzy Granular Systems
Abstract:
This paper presents an output-constrained clustering approach for fuzzy system identification and fuzzy granular system identification. The approach is unlike most existing clustering algorithms for structure identification of fuzzy systems, where the focus is on input or combined input–output clustering. The output-constrained clustering algorithm divides the output space into several partitions and each output partition is considered to be a constraint; then, input data are projected into clusters that are based on the input distribution constrained by the output partitions. By introducing the key concept of separability of a set of clusters within each output constraint, the proposed approach automatically finds an appropriate small and efficient number of clusters for each output constraint. To have an appropriate small and efficient number of clusters in each output constraint results in a more compact final system structure and better accuracy. This better performance is illustrated by experiments using benchmark function approximation and dynamic system identification.
Autors: Wang, D.;Zeng, X.;Keane, J. A.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Dec 2011, volume: 19, issue:6, pages: 1127 - 1140
Publisher: IEEE
Full litterature document
 
» An Overview of Electrospray Applications in MEMS and Microfluidic Systems
Abstract:
Integrating electrospray into microelectromechanical systems (MEMS) and microfluidic systems supports applications in diverse fields from biotechnology to aerospace. Electrospray also functions as a production tool, allowing for novel methods of MEMS fabrication. This review covers the three most significant applications of electrospray in MEMS and microfluidic systems technology: 1) as an integral part of a microfluidic device, most notably electrospray emitters for coupling a microfluidic chip to a mass spectrometer; 2) as a method for fabricating and manufacturing MEMS; and 3) for micropropulsion in aerospace applications using MEMS-based emitters. Perspectives on future research directions and opportunities are provided. [2011-0167]
Autors: Chiarot, P. R.;Sullivan, P.;Ben Mrad, R.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Dec 2011, volume: 20, issue:6, pages: 1241 - 1249
Publisher: IEEE
Full litterature document
 
» An SSVEP-Based BCI Using High Duty-Cycle Visual Flicker
Abstract:
Steady-state visual-evoked potential (SSVEP)-based brain–computer interfaces (BCIs) have generated significant interest due to their high information transfer rate (ITR). Due to the amplitude–frequency characteristic of the SSVEP, the flickering frequency of an SSVEP-based BCI is typically lower than 20 Hz to achieve a high SNR. However, a visual flicker with a flashing frequency below the critical flicker-fusion frequency often makes subjects feel flicker jerky and causes visual discomfort. This study presents a novel technique using high duty-cycle visual flicker to decrease user's visual discomfort. The proposed design uses LEDs flashing at 13.16 Hz, driven by flickering sequences consisting of repetitive stimulus cycles with a duration T (T = 76 ms). Each stimulus cycle included an ON state with a duration T and an OFF state with a duration T ( T = T + T ), and the duty cycle, defined as T / T, varied from 10.5% to 89.5%. This study also includes a questionnaire survey and analyzes the SSVEPs induced by different duty-cycle flickers. An 89.5% duty-cycle flicker, reported as a comfortable flicker, was adopted in a phase-tagged SSVEP system. Six subjects were asked to sequentially input a sequence of cursor commands with the 25.08-bits/min ITR.
Autors: Lee, P.-L.;Yeh, C.-L.;Cheng, J. Y.-S.;Yang, C.-Y.;Lan, G. -Y.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Dec 2011, volume: 58, issue:12, pages: 3350 - 3359
Publisher: IEEE
Full litterature document
 
» An Ultralow-Power Wireless Camera Node: Development and Performance Analysis
Abstract:
This paper presents the design principles underlying the video nodes of long-lifetime wireless networks. The hardware and firmware architectures of the system are described in detail, along with the system-power-consumption model. A prototype is introduced to validate the proposed approach. The system mounts a Flash-based field-programmable gate array and a high-dynamic-range complementary metal-oxide-semiconductor custom vision sensor. Accurate power measurements show that the overall consumption is 4.2 mW at 3.3 V in the worst case, thus achieving an improvement of two orders of magnitude with respect to video nodes for similar applications recently proposed in the literature. Powered with a 2200-mAh 3.3-V battery, the system will exhibit a typical lifetime of about three months.
Autors: Gasparini, L.;Manduchi, R.;Gottardi, M.;Petri, D.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Dec 2011, volume: 60, issue:12, pages: 3824 - 3832
Publisher: IEEE
Full litterature document
 
» Analyses on Small-Signal Parameters and Radio-Frequency Modeling of Gate-All-Around Tunneling Field-Effect Transistors
Abstract:
The small-signal parameters of gate-all-around tunneling field-effect transistors (GAA TFETs) with different gate lengths were extracted and analyzed in terms of their gate capacitance, source–drain conductance, transconductance, distributed channel resistance, and inversion layer length. Because of the unique current drive and inversion layer formation mechanisms of a TFET compared to a conventional MOSFET, the gate-bias dependence values of the primary small-signal parameters of a GAA TFET also differ. Based on understanding these parameters, the high-frequency performances of GAA TFETs were investigated using a technology computer-aided design simulation. A nonquasi-static radio-frequency model was used to extract the small-signal parameters, which were verified up to 100 GHz. The modeling results showed excellent agreement with the -parameters up to the cutoff frequency .
Autors: Cho, S.;Lee, J. S.;Kim, K. R.;Park, B.-G.;Harris, J. S.;Kang, I. M.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Dec 2011, volume: 58, issue:12, pages: 4164 - 4171
Publisher: IEEE
Full litterature document
 
» Analysis and Design Method for High-Frequency Self-Oscillating Electronic Ballasts
Abstract:
In this paper, the analysis and design methodology of a high-frequency self-oscillating (SO) electronic ballast with lamp current control are presented. SO electronic ballasts have two important drawbacks: First, the lamp current varies according to the ac input voltage, causing undesired effects in the lamp brightness, and second, the design method lacks precision at very high frequency operation (greater than 200 kHz) mainly due to the parasitic capacitance. The ballast is modeled by using the descriptive function method and the extended Nyquist criterion; the model of the ballast includes a control circuit and takes into account the high-frequency effect of the MOSFET parasitic capacitance . Finally, experimental results of a 38-W SO electronic ballast prototype with lamp current control for high-intensity discharge lamps are presented to validate the analysis and the proposed methodology. The switching frequency is selected at 2 MHz in order to avoid the acoustic resonance problem.
Autors: Flores-Garcia, E.;Ponce-Silva, M.;Vela-Valdes, L. G.;Juarez, M. A.;Hernandez-Gonzalez, L.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Dec 2011, volume: 47, issue:6, pages: 2430 - 2436
Publisher: IEEE
Full litterature document
 
» Analysis and Design of Millimeter-Wave Low-Power CMOS LNA With Transformer-Multicascode Topology
Abstract:
In this paper, the analysis and design of a CMOS multicascode configuration with a noise-reduction transformer topology are presented. Two low-power (LP), miniature, and wideband low-noise amplifiers (LNAs) were designed and fabricated for demonstration. One with a transformer triple-cascode configuration was designed at -band, and the other with a transformer quadruple-cascode configuration was designed at -band. Both of the two LNAs were fabricated using 90-nm LP CMOS technology. To minimize the noise figure (NF) and maximize both the small-signal gain and 3-dB bandwidth, the noise-reduction transformers are designed and placed between transistors of the triple- and quadruple-cascode devices. Based on this approach, the -band LNA has a gain of 20.3 dB and an NF of 4.6 dB at 40 GHz, with a power consumption of 15 mW. Both of the LNA utilize a 3-V supply voltage, but the drain source voltage of each device in the multicascode configuration is below 1 V. The -band LNA presents a gain of 12.7 dB from 43 to 58 GHz and a minimum NF of 4.7 dB at 62.5 GHz with a power consumption of 18 mW. The chip size of the - and -band LNAs are and , including all the testing pads. Compared with the conventional cascode LNAs, the proposed transformer triple-cascode LNA has a better NF, wider 3-dB bandwidth, and lower power consumption, whereas the transformer qu- - adruple-cascode LNA features even higher gain performance.
Autors: Yeh, H.-C.;Liao, Z.-Y.;Wang, H.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Dec 2011, volume: 59, issue:12, pages: 3441 - 3454
Publisher: IEEE
Full litterature document
 
» Analysis and optimisation of lateral thin-film silicon-on-insulator (SOI) PMOS transistor with an NBL layer in the drift region
Abstract:

Highlights

? Low RESURF effectiveness found in conventional P-channel LDMOS on thin-SOI. ? NBL layer is inserted in the drift region by high energy implantation. ? Significant improvement of static performance in the proposed LDPMOS. ? Further improvement is observed by using STI partially covering the drift region.


Autors: This paper analyses the experimental results of voltage capability (VBR > 120 V) and output characteristics of a new lateral power P-channel MOS transistors manufactured on a 0.18 ?m SOI CMOS technology by means of TCAD numerical simulations. The pro
Appeared in: Solid-State Electronics
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Analysis of Acoustic Feedback/Echo Cancellation in Multiple-Microphone and Single-Loudspeaker Systems Using a Power Transfer Function Method
Abstract:
In this work, we analyze a general multiple-microphone and single-loudspeaker audio processing system, where a multichannel adaptive system is used to cancel the effect of acoustic feedback/echo, and a beamformer processes the feedback/echo canceled signals. We introduce and derive an accurate approximation of a frequency domain measure—the power transfer function—and show how it can be used to predict the convergence rate, system stability bound and the steady-state behavior of the entire cancellation system across frequency and time. We consider three example adaptive algorithms in the cancellation system: the least mean square, normalized least mean square, and the recursive least squares algorithms. Furthermore, we derive expressions to determine the step size parameter in the adaptive algorithms to achieve a desired system behavior, e.g., convergence rate at a specific frequency. Finally, we compare and discuss the performance of all three adaptive algorithms, and we verify the derived expressions through simulation experiments.
Autors: Guo, M.;Elmedyb, T. B.;Jensen, S. H.;Jensen, J.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Dec 2011, volume: 59, issue:12, pages: 5774 - 5788
Publisher: IEEE
Full litterature document
 
» Analysis of Boost PFC Converters Operating in the Discontinuous Conduction Mode
Abstract:
As power factor correction (PFC) converters for low-power applications usually operate in the discontinuous conduction mode (DCM), operating in continuous conduction mode (CCM) will produce input current distortion. This distortion can be observed in a few switching cycles of one line cycle. Asynchronous switching maps are derived to obtain the time-domain waveforms of input current and output voltage. It can be seen that the cause of the distortion is the change in the current conduction mode. A model for PFC converters operating in DCM with fixed switching frequency and duty-ratio is developed, which can predict the converter operation mode under practical circumstances. Analysis of the output voltage and power limitations is provided based on the proposed model. Simulation and experimental results are presented to verify the proposed method.
Autors: Zhang, X.;Spencer, J. W.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Dec 2011, volume: 26, issue:12, pages: 3621 - 3628
Publisher: IEEE
Full litterature document
 
» Analysis of Classical Root-Finding Methods Applied to Digital Maximum Power Point Tracking for Sustainable Photovoltaic Energy Generation
Abstract:
This paper examines the application of various classical root-finding methods to digital maximum power point tracking (DMPPT). An overview of root-finding methods such as the Newton Raphson method, Secant method, bisection method, regula falsi method, and a proposed modified regula falsi method (MRFM) applied to photovoltaic (PV) applications is presented. These methods are compared among themselves. Some of their features are also compared with other commonly used maximum power point (MPP) tracking methods. Issues found when implementing these root-finding methods based on continuous variables in a digital domain are explored. Some of these discussed issues include numerical stability, digital implementation of differential operators, and quantization error. Convergence speed is also explored. The analysis is used to provide practical insights into the design of a DMPPT based on classical root-finding algorithms. A new DMPPT based on an MRFM is proposed and used as the basis for the discussion. It is shown that this proposed method is faster than the other discussed methods that ensure convergence to the MPP. The discussion is approached from a practical perspective and also includes theoretical analysis to support the observations. Extensive simulation and experimental results with hardware prototypes verify the analysis.
Autors: Chun, S.;Kwasinski, A.;
Appeared in: IEEE Transactions on Power Electronics
Publication date: Dec 2011, volume: 26, issue:12, pages: 3730 - 3743
Publisher: IEEE
Full litterature document
 
» Analysis of Detection Methods of RF Vibrometer for Complex Motion Measurement
Abstract:
In this paper, the detection technique of the previously reported wavelength-division-sensing RF vibrometer is thoroughly analyzed by investigating the Bessel function coefficient of harmonics in the baseband spectrum. The analysis provides guidelines on the selection of harmonic pairs to help improve detection accuracy and reliability. A new detection method that utilizes multiple harmonic pairs under a fixed carrier frequency proves to be a more reliable approach for RF vibrometers. The sensitivity of harmonic amplitude ratio to the excess phase angle is explored as well. The results show that by using insensitive harmonic pairs, information about the characteristics of the vibration system and the external driving force are still attainable even when the phase angles are unknown. Real-time monitoring of various harmonic vibrations has been realized through a LabVIEW program with a user interface that provides visualization of the vibration patterns. The function of through-wall detection of the RF vibrometer has also been verified by conducting all measurements behind a wall with a detection distance of 1.5 m.
Autors: Yan, Y.;Cattafesta, L.;Li, C.;Lin, J.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Dec 2011, volume: 59, issue:12, pages: 3556 - 3566
Publisher: IEEE
Full litterature document
 
» Analysis of Nonaqueous Electrowetting Fluids for Displays
Abstract:
Water remains the most extensively studied electrowetting fluid, but few reports exist on nonaqueous conducting solvents. Reported herein is a complete analysis of alternate fluids for electrowetting devices and displays. Emphasis is provided on real-world testing parameters, including contact angle response and immiscibility with oil, environmental range, interfacial tension, ionic content and influence on dielectric reliability, compatibility with additives such as soluble dyes or particle dispersions, and cross-diffusion of fluids or solutes. Out of 16 preselected fluids, six exhibited electrowetting performance comparable to the best aqueous:surfactant solutions. Use of the nonaqueous fluids in advanced display devices is also demonstrated.
Autors: Chevalliot, S.;Heikenfeld, J.;Clapp, L.;Milarcik, A.;Vilner, S.;
Appeared in: Journal of Display Technology
Publication date: Dec 2011, volume: 7, issue:12, pages: 649 - 656
Publisher: IEEE
Full litterature document
 
» Analysis of sensor fingerprint for source camera identification
Abstract:
In the field of digital image forensics, image source identification aims at establishing a link between an image and the device that generated it. All digital pictures taken by the same device are overlaid by a specific pattern, which is a unique and intrinsic fingerprint of the acquisition device. Such a fingerprint can be estimated as the difference between the content and its denoised version, obtained via denoising filter processing. Proposed is a performance comparison of different filters for source identification purposes.
Autors: Conotter, V.;Boato, G.;
Appeared in: Electronics Letters
Publication date: Dec 2011, volume: 47, issue:25, pages: 1366 - 1367
Publisher: IEEE
Full litterature document
 
» Analysis of temperature variation influence on the analog performance of 45° rotated triple-gate nMuGFETs
Abstract:

Highlights

? Analog performance of triple-gate MuGFETs fabricated in 45° rotated SOI substrates. ? Influence of fin width and temperature ranging from 250 K to 400 K is studied. ? Larger carrier mobility increase with temperature for rotated MuGFETs. ? The output conductance is weakly affected by the substrate rotation. ? Rotated MuGFETs present similar voltage gain and higher unity-gain frequency.


Autors: This work presents the analog performance of n-type triple-gate MuGFETs with high-kdielectrics and TiN gate material fabricated in 45° rotated SOI substrates comparing their performance with standard MuGFETs fabricated without substrate rotation. Dif
Appeared in: Solid-State Electronics
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Analysis of the Effective Refractive Index of Silicon Waveguides Through the Constructive and Destructive Interference in a Mach–Zehnder Interferometer
Abstract:
This paper introduces a method of measuring the delta between the effective refractive index of a silicon waveguide and a waveguide with wider dimensions through the constructive and destructive interference in a Mach–Zehnder interferometer (MZI). The method consists of a fixed effective refractive index variation incorporated by tapering one of the arms in the interferometer to a wider waveguide dimension. The MZI consists of a Y-branch splitter and a multimode interference (MMI) coupler. The Y-branch splitter splits the input light 50/50 into the two arms, and the MMI is used for recombination of the two arms. A change in the effective refractive index of one arm in comparison with the other arm in the interferometer will introduce a phase difference on recombination in the MMI. The MMI has the following three ports: the top and bottom output ports, which are the antisymmetric outputs, and the middle port, which is the symmetric output. When the two signals are in phase, all the light is coupled into the symmetric port, and when the two inputs are out of phase, the light is coupled 50/50 into the antisymmetric ports. The interferometer is designed on a silicon-on-insulator (SOI) wafer and fabricated through IMEC Belgium. Theoretical, simulation, and measured results are presented and compared.
Autors: Dattner, Y.;Yadid-Pecht, O.;
Appeared in: IEEE Photonics Journal
Publication date: Dec 2011, volume: 3, issue:6, pages: 1123 - 1132
Publisher: IEEE
Full litterature document
 
» Analysis, Design, and Implementation of Virtual Impedance for Power Electronics Interfaced Distributed Generation
Abstract:
This paper presents a virtual impedance design and implementation approach for power electronics interfaced distributed generation (DG) units. To improve system stability and prevent power couplings, the virtual impedances can be placed between interfacing converter outputs and the main grid. However, optimal design of the impedance value, robust implementation of the virtual impedance, and proper utilization of the virtual impedance for DG performance enhancement are key for the virtual impedance concept. In this paper, flexible small-signal models of microgrids in different operation modes are developed first. Based on the developed microgrid models, the desired DG impedance range is determined considering the stability, transient response, and power flow performance of DG units. A robust virtual impedance implementation method is also presented, which can alleviate voltage distortion problems caused by harmonic loads compared to the effects of physical impedances. Furthermore, an adaptive impedance concept is proposed to further improve power control performances during the transient and grid faults. Simulation and experimental results are provided to validate the impedance design approach, the virtual impedance implementation method, and the proposed adaptive transient impedance control strategies.
Autors: He, J.;Li, Y. W.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Dec 2011, volume: 47, issue:6, pages: 2525 - 2538
Publisher: IEEE
Full litterature document
 
» Analytic Propagation Model for Wireless Body-Area Networks
Abstract:
Wave propagation in wireless body area networks (WBAN) is analytically modeled as a polarized point source close to an elliptic lossy dielectric cylinder. Using the Fourier transform along the axes, the expansion in terms of Mathieu functions in cross section, and the impedance boundary condition (IBC) on surface, the field distribution outside the cylinder can be formulated. In particular, the path gain of propagation around the human body is described in detail for 915-MHz and 2.40-GHz bands toward industrial, scientific, and medical (ISM) applications.
Autors: Ma, D.;Zhang, W. X.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Dec 2011, volume: 59, issue:12, pages: 4749 - 4756
Publisher: IEEE
Full litterature document
 
» Analytical Evaluation of Fractional Frequency Reuse for OFDMA Cellular Networks
Abstract:
Fractional frequency reuse (FFR) is an interference management technique well-suited to OFDMA-based cellular networks wherein the bandwidth of the cells is partitioned into regions with different frequency reuse factors. To date, FFR techniques have been typically been evaluated through system-level simulations using a hexagonal grid for the base station locations. This paper instead focuses on analytically evaluating the two main types of FFR deployments - Strict FFR and Soft Frequency Reuse (SFR) - using a Poisson point process to model the base station locations. The results are compared with the standard grid model and an actual urban deployment. Under reasonable special cases for modern cellular networks, our results reduce to simple closed-form expressions, which provide insight into system design guidelines and the relative merits of Strict FFR, SFR, universal reuse, and fixed frequency reuse. Finally, a SINR-proportional resource allocation strategy is proposed based on the analytical expressions and we observe that FFR provides an increase in the sum-rate as well as the well-known benefit of improved coverage for cell-edge users.
Autors: Novlan, Thomas David;Ganti, Radha Krishna;Ghosh, Arunabha;Andrews, Jeffrey G.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Dec 2011, volume: 10, issue:12, pages: 4294 - 4305
Publisher: IEEE
Full litterature document
 
» Analytical Expressions for Doped Polycrystalline Silicon Thin-Film Transistors in Above-Threshold Regime Consistent With Pao–Sah Model Considering Trapped Charge Effect
Abstract:
Based on a depleted and trapped charge analysis, threshold-voltage-based analytical drain current and capacitance expressions are presented in the above-threshold regime for doped polycrystalline silicon thin-film transistors assuming a symmetric exponential distribution (V-shaped) density of trap states (DOS) within the energy gap. A parameter is proposed by considering “the trapped charge effect,” i.e., the increase of trapped charge with increasing gate voltage. The relationship between the parameter and the DOS is clarified. In particular, the expressions are consistent with the Pao–Sah model. Good agreements are achieved by comparing this paper with experimental data.
Autors: He, H.;Zheng, X.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Dec 2011, volume: 58, issue:12, pages: 4324 - 4332
Publisher: IEEE
Full litterature document
 
» Analytical modeling of clamp band joint under external bending moment
Abstract:
Clamp band joints are commonly employed as mechanical fasteners of the launching system in the aerospace industry. Appropriate modeling of the joint stiffness is essential to predicting the dynamic behavior of the launching system accurately and efficiently. In this paper, an analytical model for the bending stiffness of the clamp band joint is developed and then validated by finite element analyses. The bending behavior of the clamp band joint is studied using the proposed analytical model. Parametric studies are also performed to investigate the effects of the preload and the structural parameters on the bending stiffness of the clamp band joint.
Autors: Z.Y. Qin, S.Z. Yan, F.L. Chu
Appeared in: Aerospace Science and Technology
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Analytical Open-Circuit Magnetic Field Distribution of Slotless Brushless Permanent-Magnet Machines With Rotor Eccentricity
Abstract:
Analytical expressions for the no-load magnetic field distribution of slotless brushless permanent-magnet (PM) machines with static, dynamic, and mixed rotor eccentricities are presented. The proposed analytical expressions can be used for slotless brushless PM machines with any radius-independent magnetization pattern. The analytical expressions and the results for six different magnetization patterns are presented. Based on the analytical magnetic field distribution, the line and phase back-electromotive force waveforms, local traction components and unbalanced magnetic forces are obtained. The analytical results are compared with those from finite-element analyses to validate the derived expressions.
Autors: Rahideh, A.;Korakianitis, T.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Dec 2011, volume: 47, issue:12, pages: 4791 - 4808
Publisher: IEEE
Full litterature document
 
» Analytical tools to assess the voltage stability of induction-based distributed generators
Abstract:

Highlights

? A method is presented to analyse the steady-state behaviour of induction generators. ? The method can be used to identify voltage stability issues of induction generators. ? The method can be used to assess the maximum output power of induction generators.


Autors: The installation of induction distributed generators should be preceded by a careful study in order to determine if the point of common coupling is suitable for transmission of the generated power, keeping acceptable power quality and system stabilit
Appeared in: International Journal of Electrical Power & Energy Systems
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Analyzing Random Network Coding With Differential Equations and Differential Inclusions
Abstract:
We develop a framework based on differential equations (DE) and differential inclusions (DI) for analyzing Random Network Coding (RNC) in an arbitrary wireless network. The DEDI framework serves as a powerful numerical and analytical tool to study RNC. For demonstration, we first build a system of DE's with this framework, under the fluid approximation, to model the means of the rank evolution processes. By converting this system to DI's and explicitly solving them, we show that the average multicast throughput is equal to the min-cut bound. We then turn to the precise system of DE's regarding the means and variances of the rank evolution processes. By analyzing this system, we show that the rank evolution processes asymptotically concentrate to the solution of the DI's obtained previously. From this result, it immediately follows that the min-cut bound can be achieved as the number of source packets becomes large. We demonstrate the numerical accuracy and flexibility in performance analysis enabled by the DEDI framework via illustrative examples of networks with multiple multicast sessions, complex topology and correlated reception. We also briefly discuss its application in MAC and PHY adaptation and the extension to Random Coupon Selection.
Autors: Zhang, D.;Mandayam, N. B.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Dec 2011, volume: 57, issue:12, pages: 7932 - 7949
Publisher: IEEE
Full litterature document
 
» Application of a Rat Hindlimb Model: A Prediction of Force Spaces Reachable Through Stimulation of Nerve Fascicles
Abstract:
A device to generate standing or locomotion through chronically placed electrodes has not been fully developed due in part to limitations of clinical experimentation and the high number of muscle activation inputs of the leg. We investigated the feasibility of functional electrical stimulation paradigms that minimize the input dimensions for controlling the limbs by stimulating at nerve fascicles, utilizing a model of the rat hindlimb, which combined previously collected morphological data with muscle physiological parameters presented herein. As validation of the model, we investigated the suitability of a lumped-parameter model for the prediction of muscle activation during dynamic tasks. Using the validated model, we found that the space of forces producible through activation of muscle groups sharing common nerve fascicles was nonlinearly dependent on the number of discrete muscle groups that could be individually activated (equivalently, the neuroanatomical level of activation). Seven commonly innervated muscle groups were sufficient to produce 78% of the force space producible through individual activation of the 42 modeled hindlimb muscles. This novel, neuroanatomically derived reduction in input dimension emphasizes the potential to simplify controllers for functional electrical stimulation to improve functional recovery after a neuromuscular injury.
Autors: Johnson, W. L.;Jindrich, D. L.;Zhong, H.;Roy, R. R.;Edgerton, V. R.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Dec 2011, volume: 58, issue:12, pages: 3328 - 3338
Publisher: IEEE
Full litterature document
 
» Application of an orthotropy rescaling method to edge cracks and kinked cracks in orthotropic two-dimensional solids
Abstract:
Oblique edge cracks and kinked cracks in orthotropic materials with inclined principal material directions under inplane loadings are investigated. The Stroh formalism is modified by introducing new complex functions, which recovers a classical solution for a degenerate orthotropic material with multiple characteristic roots. An orthotropy rescaling technique is presented based on the modified Stroh formalism. Stress intensity factors for edge cracks as well as kinked cracks are obtained in terms of solutions for a material with cubic symmetry by applying the orthotropy rescaling method. Explicit expressions of the stress intensity factors for a degenerate orthotropic material are obtained in terms of solutions for an isotropic material. The effects of orthotropic parameter, material orientation, and crack angle on the stress intensity factors for the degenerate orthotropic material are discussed. The stress intensity factors for cubic symmetry materials are calculated from finite element analyses, which can be used to evaluate the stress intensity factors for orthotropic materials. The energy release rate for the kinked crack in an orthotropic material is also obtained.
Autors: H.G. Beom, C.B. Cui, H.S. Jang
Appeared in: International Journal of Engineering Science
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Application of Cross-Shaped Resonator to the Ultra Wideband Bandpass Filter Design
Abstract:
An ultra-wideband (UWB) bandpass filter (BPF) with two cascaded cross-shaped resonators is proposed and implemented. As the starting work of this letter, a cross-shaped resonator with wide passband is introduced. With the use of even- and odd-mode approach, this initial resonator is characterized and designed to build up a UWB BPF. And then, a cascaded UWB BPF is fabricated to satisfy Federal Communications Commission indoor mask.
Autors: Wang, H.;Yang, G.;Kang, W.;Miao, C.;Wu, W.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Dec 2011, volume: 21, issue:12, pages: 667 - 669
Publisher: IEEE
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» Application of DCIM on Marine Controlled-Source Electromagnetic Survey
Abstract:
The discrete complex image method (DCIM) is used to calculate the mixed-potential electric field integral equation. The DCIM has been used broadly in high-frequency domain, and now is successfully introduced to the extremely low-frequency situation of marine controlled-source electromagnetic (MCSEM) survey. The integral path in high-frequency situation does not hold valid for extremely low-frequency situation. The reason can be ascribed to the change of wave number formulas. A new integral path suitable for the extremely low-frequency situation is proposed. The appropriate ranges of the parameters used in DCIM are given. The computation is stable at these considerably large ranges. The results of a five-layer model calculated with DCIM are compared with those with the filter method and the direct integral method. The computation time with DCIM is comparable to the time with filter method. The effects of water depth, upper-sediment thickness, and oil-layer thickness are studied with DCIM. The results show that electric field varies with the change of thickness. The effects accord to the physical meanings of MCSEM survey. It is safe to conclude that the DCIM with the new path is valid in MCSEM survey.
Autors: Ju, H.;Fang, G.;Lin, Z.;Zhang, F.;Huang, L.;Ji, Y.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Dec 2011, volume: 59, issue:12, pages: 4803 - 4810
Publisher: IEEE
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» Application of IFT and SPSA to Servo System Control
Abstract:
This paper treats the application of two data-based model-free gradient-based stochastic optimization techniques, i.e., iterative feedback tuning (IFT) and simultaneous perturbation stochastic approximation (SPSA), to servo system control. The representative case of controlled processes modeled by second-order systems with an integral component is discussed. New IFT and SPSA algorithms are suggested to tune the parameters of the state feedback controllers with an integrator in the linear-quadratic-Gaussian (LQG) problem formulation. An implementation case study concerning the LQG-based design of an angular position controller for a direct current servo system laboratory equipment is included to highlight the pros and cons of IFT and SPSA from an application's point of view. The comparison of IFT and SPSA algorithms is focused on an insight into their implementation.
Autors: Radac, M.-B.;Precup, R.-E.;Petriu, E. M.;Preitl, S.;
Appeared in: IEEE Transactions on Neural Networks
Publication date: Dec 2011, volume: 22, issue:12, pages: 2363 - 2375
Publisher: IEEE
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» Application of natural computing algorithms to maximum likelihood estimation of direction of arrival
Abstract:

Highlights

? We apply a set of natural computing algorithms to the problem of ML-DOA estimation. ? We analyze the estimation error as a function of the SNR in different scenarios. ? The studied algorithms reach the performance of the ML estimator.


Autors: This work presents a study of the performance of populational meta-heuristics belonging to the field of natural computing when applied to the problem of direction of arrival (DOA) estimation, as well as an overview of the literature about the use of
Appeared in: Signal Processing
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Application of Spatial Bandwidth Concepts to MAS Pole Location for Dielectric Cylinders
Abstract:
The concept of effective spatial bandwidth (EBW) is extended from the case of an MAS solution for perfectly conducting (PEC) cylinders to dielectric cylinders. It is shown that the ideas and results for the conducting cylinder apply in a straightforward manner to the dielectric case. For the dielectric case, there are two auxiliary surfaces. Because the EBW calculations are independent of the scatterer material, the auxiliary surface for the scattered field will follow the same guidelines for both the PEC and dielectric cases. The guidelines for the second auxiliary surface are described and verified here. Guidelines for both a plane wave incident field and a monopole line source incident field are provided.
Autors: Richie, J. E.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Dec 2011, volume: 59, issue:12, pages: 4861 - 4864
Publisher: IEEE
Full litterature document
 
» Application of the LP-ELM Model on Transportation System Lifetime Optimization
Abstract:
Considering factors such as economic costs and lives, an unreliable transportation system is more likely to cause severe consequences. Therefore, reliability optimization of transportation systems has attracted much attention over the past several decades. The traditional reliability optimization design is usually focused on redundancy allocation or reliability redundancy allocation. In practice, the operation process usually has a significant influence on the transportation system lifetime. By combining linear programming (LP) and extreme learning machine (ELM), a two-stage approach is proposed to optimize the transportation system lifetime, in which a semi-Markov model (SMM) is used to model the operation process. In the proposed method, we first formulate the optimization problem as an LP model, and the LP algorithm is utilized to search for the approximate optimal state probabilities. After data production and sample selection, ELM is trained with the produced training data and used to predict the optimal sojourn time distribution parameters. Applications on three different cases demonstrate that a higher lifetime can be ensured for the transportation system by using the proposed method.
Autors: Sun, Z.-L.;Ng, K. M.;Soszynska-Budny, J.;Habibullah, M. S.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Dec 2011, volume: 12, issue:4, pages: 1484 - 1494
Publisher: IEEE
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» Applications of Stochastic Ordering to Wireless Communications
Abstract:
Stochastic orders are binary relations defined on probability distributions which capture intuitive notions like being larger or being more variable. This paper introduces stochastic ordering of instantaneous SNRs of fading channels as a tool to compare the performance of communication systems over different channels. Stochastic orders unify existing performance metrics such as ergodic capacity, and metrics based on error rate functions for commonly used modulation schemes through their relation with convex and completely monotonic (c.m.) functions. Toward this goal, performance metrics such as instantaneous error rates of M-QAM and M-PSK modulations are shown to be c.m. functions of the instantaneous SNR, while metrics such as the instantaneous capacity are seen to have a completely monotonic derivative (c.m.d.). It is shown that the frequently used parametric fading distributions for modeling line of sight (LoS) exhibit a monotonicity in the LoS parameter with respect to the stochastic Laplace transform order. Using stochastic orders, average performance of systems involving multiple random variables are compared over different channels, even when closed form expressions for such averages are not tractable. These include diversity combining schemes, relay networks, and signal detection over fading channels with non-Gaussian additive noise, which are investigated herein. Simulations are also provided to corroborate our results.
Autors: Tepedelenlioglu, Cihan;Rajan, Adithya;Zhang, Yuan;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Dec 2011, volume: 10, issue:12, pages: 4249 - 4257
Publisher: IEEE
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» Applications of the BIOPHYS Algorithm for Physically-Based Retrieval of Biophysical, Structural and Forest Disturbance Information
Abstract:
Canopy reflectance model inversion using look-up table approaches provides powerful and flexible options for deriving improved forest biophysical structural information (BSI) compared with traditional statistical empirical methods. The BIOPHYS algorithm is an improved, physically-based inversion approach for deriving BSI for independent use and validation and for monitoring, inventory and quantifying forest disturbance as well as input to ecosystem, climate and carbon models. Based on the multiple-forward mode (MFM) inversion approach, BIOPHYS results were summarised from different studies (Minnesota/NASA COVER; Virginia/LEDAPS; Saskatchewan/BOREAS), sensors (airborne MMR; Landsat; MODIS) and models (GeoSail; GOMS). Applications output included forest density, height, crown dimension, branch and green leaf area, canopy cover, disturbance estimates based on multi-temporal chronosequences, and structural change following recovery from forest fires over the last century. Good correspondences with validation field data were obtained. Integrated analyses of multiple solar and view angle imagery further improved retrievals compared with single pass data. Quantifying ecosystem dynamics such as the area and percent of forest disturbance, early regrowth and succession provide essential inputs to process-driven models of carbon flux. BIOPHYS is well suited for large-area, multi-temporal applications involving multiple image sets and mosaics for assessing vegetation disturbance and quantifying biophysical structural dynamics and change. It is also suitable for integration with forest inventory, monitoring, updating, and other programs.
Autors: Peddle, D. R.;Huemmrich, K. F.;Hall, F. G.;Masek, J. G.;Soenen, S. A.;Jackson, C. D.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Dec 2011, volume: 4, issue:4, pages: 971 - 982
Publisher: IEEE
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» Applications of the Trace Transform in Surface Wave Attenuation on Seismic Records
Abstract:
A main target of seismic data processing is to remove the surface waves and improve the quality of seismic records. Here, we propose a Co-Core Trace transform filtering based on the Trace transform from image processing and apply it to seismic surface wave attenuation. The transform is designed according to the distribution and propagation of the surface waves. In the transform domain, the energies of surface waves are significantly enhanced and could be filtered out with a relative threshold, while the reflection events are saved due to the conspicuous disparity. Experiments on both synthetic model and field data demonstrate that the proposed algorithm performs well both in surface wave attenuation and reflected signal preservation, besides presenting advantages over some conventional methods.
Autors: Wu, N.;Li, Y.;Yang, B.;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Dec 2011, volume: 49, issue:12, pages: 4997 - 5007
Publisher: IEEE
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» Applications, Architectures, and Protocol Design Issues for Mobile Social Networks: A Survey
Abstract:
Autors: Falk, H.;
Appeared in: Proceedings of the IEEE
Publication date: Dec 2011, volume: 99, issue:12, pages: 2125 - 2129
Publisher: IEEE
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» Applying One-Comparator Counter-Based Sampling to Current Sharing Control of Multichannel LED Strings
Abstract:
In this paper, a fully digitalized current sharing strategy without any analog-to-digital converter (ADC) is presented and applied to light-emitting diode (LED) lighting. By doing so, the cost for digital control is reduced significantly due to no ADC used. Aside from this, LED dimming is easy to realize. Above all, the proposed current sharing method has the capability of resisting variations in input voltage and component parameter. Such a control topology is demonstrated by some experiments and hence is very suitable for LED street lighting.
Autors: Hwu, K. I.;Yau, Y. T.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Dec 2011, volume: 47, issue:6, pages: 2413 - 2421
Publisher: IEEE
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» Approach for Transforming Linear Constraints on Petri Nets
Abstract:
An efficient supervisor synthesis method is proposed based on the constraint transformation, since enforcing a logic expression of linear constraints on Petri nets essentially involves finding admissible constraints. It consists of cooperative algorithms that are used to obtain the logic expression of constraints for any set of forbidden markings, to remove redundant constraints using the quantity information of constraints, to judge the existence of a permissive supervisor, to equivalently reduce multiple constraints into a single one using net structural properties, and to approach the admissible constraints from the original ones for ordinary Petri nets. These algorithms are derived from a series of theorems and lemmas presented to construct the theory of constraint transformation or reduction. In addition, the linear constraint, whose uncontrollable subnet is a forward-concurrent free net, can be equivalently transformed into an admissible linear constraint using this method.
Autors: Luo, J.;Nonami, K.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Dec 2011, volume: 56, issue:12, pages: 2751 - 2765
Publisher: IEEE
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» Approximate all nearest neighbor search for high dimensional entropy estimation for image registration
Abstract:

Highlights

Kozachenko-Leonenko entropy estimator is based on nearest neighbor (NN) distances.Our target application is image registration.We use tight bounding boxes, all-NN best-bin-first search, handle multiplicites.We compare ANN, FLANN, LSH and our own BBF all-NN search algorithms.FLANN and ANN very good for general data, our method the best for image data.


Autors: Information theoretic criteria such as mutual information are often used as similarity measures for inter-modality image registration. For better performance, it is useful to consider vector-valued pixel features. However, this leads to the task of e
Appeared in: Signal Processing
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Approximate Dynamic Programming for Optimal Stationary Control With Control-Dependent Noise
Abstract:
This brief studies the stochastic optimal control problem via reinforcement learning and approximate/adaptive dynamic programming (ADP). A policy iteration algorithm is derived in the presence of both additive and multiplicative noise using Itô calculus. The expectation of the approximated cost matrix is guaranteed to converge to the solution of some algebraic Riccati equation that gives rise to the optimal cost value. Moreover, the covariance of the approximated cost matrix can be reduced by increasing the length of time interval between two consecutive iterations. Finally, a numerical example is given to illustrate the efficiency of the proposed ADP methodology.
Autors: Jiang, Y.;Jiang, Z.-P.;
Appeared in: IEEE Transactions on Neural Networks
Publication date: Dec 2011, volume: 22, issue:12, pages: 2392 - 2398
Publisher: IEEE
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» Approximate MAP Detection With Ordering and Successive Processing for Iterative Detection and Decoding in MIMO Systems
Abstract:
For iterative detection and decoding (IDD) in multiple-input multiple-output (MIMO) systems, the MIMO detector needs to provide soft-decisions. Since the complexity of the maximum a posteriori probability (MAP) detector grows exponentially with the number of transmit antennas, various suboptimal detectors are proposed to exploit the tradeoff between complexity and performance. Among them, the minimum mean square error (MMSE)-soft cancellation (SC) detector has an excellent tradeoff. In this paper, by noting that the MMSE-SC detector is an approximate MAP detector, another approximate MAP detector that uses successive processing is proposed. The proposed successive detector can provide a better performance than the MMSE-SC detector, while its complexity is comparable with that of the MMSE-SC detector. An interesting feature of the proposed successive detector is that the tradeoff between complexity and performance can be exploited by a single parameter, which could be an important control parameter in practical implementations.
Autors: Choi, J.;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Dec 2011, volume: 5, issue:8, pages: 1415 - 1425
Publisher: IEEE
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» APSK Constellation with Gray Mapping
Abstract:
Amplitude phase shift keying (APSK) constellation is superior to its quadrature amplitude modulation (QAM) counterpart from the mutual information point of view. However, due to the lack of Gray mapping, it introduces high independent demapping loss. In this letter, a special kind of APSK constellations with Gray mapping (Gray-APSK) is proposed, which provides considerable shaping gain compared with the QAM constellations with Gray mapping (Gray-QAM) in both independent and iterative demapping scenarios, as verified by average mutual information analysis and bit error rate simulations.
Autors: Liu, Zaishuang;Xie, Qiuliang;Peng, Kewu;Yang, Zhixing;
Appeared in: IEEE Communications Letters
Publication date: Dec 2011, volume: 15, issue:12, pages: 1271 - 1273
Publisher: IEEE
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» Arbitrary-Order Bandwidth-Tunable Temporal Differentiator Using a Programmable Optical Pulse Shaper
Abstract:
We experimentally demonstrate an arbitrary-order bandwidth-tunable differentiator using a programmable optical pulse shaper, which is based on spatial diffraction and liquid crystal modulation. The impact of bandwidth of optical pulse shaper on output power and pulsewidth of differentiation is theoretically analyzed. In the experiment, all first-order, second-order, and third-order differentiators with bandwidths of 80, 160, and 320 GHz are obtained with average deviations of less than 4.2%. The differentiation of pseudorandom nonreturn-to-zero (NRZ) signals at 10 and 20 Gbit/s is also discussed.
Autors: Dong, J.;Yu, Y.;Zhang, Y.;Luo, B.;Yang, T.;Zhang, X.;
Appeared in: IEEE Photonics Journal
Publication date: Dec 2011, volume: 3, issue:6, pages: 996 - 1003
Publisher: IEEE
Full litterature document
 
» Are Field-Programmable Gate Arrays Ready for the Mainstream?
Abstract:
Although field-programmable gate arrays (FPGAs) can offer a significant performance advantage over alternate devices, they remain a niche technology. This column addresses the barriers to widespread FPGA use and explores the innovations necessary to eliminate these barriers.
Autors: Stitt, Greg;
Appeared in: IEEE Micro
Publication date: Dec 2011, volume: 31, issue:6, pages: 58 - 63
Publisher: IEEE
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» Are Password Requirements too Difficult?
Abstract:
It might be prudent to enhance password mechanisms while training users to take the additional responsibility of managing passwords.
Autors: Schaffer, Kim;
Appeared in: Computer
Publication date: Dec 2011, volume: 44, issue:12, pages: 90 - 92
Publisher: IEEE
Full litterature document
 
» Artificial Intelligence in modelling the complexity of Mediterranean landscape transformations
Abstract:

Highlights

? Landscape transformations are modelled using Artificial Intelligence language. ? Artificial Intelligence can be used to simulate landscape transformations. ? Causes and effects of Mediterranean landscape transformations can be modelled. ? Future landscape states can be predicted as well as land degradation status.


Autors: In this paper, it is shown how a system can be created by using methods of Artificial Intelligence, designated (a) to provide the user with information about the transformations of Mediterranean-type landscapes in an interactive way, (b) to allow the
Appeared in: Computers and Electronics in Agriculture
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Artificial Noise Generation from Cooperative Relays for Everlasting Secrecy in Two-Hop Wireless Networks
Abstract:
The secure transmission of information in wireless networks without knowledge of eavesdropper channels or locations is considered. Two key mechanisms are employed: artificial noise generation from system nodes other than the transmitter and receiver, and a form of multi-user diversity that allows message reception in the presence of the artificial noise. We determine the maximum number of independently-operating and uniformly distributed eavesdroppers that can be present while the desired secrecy is achieved with high probability in the limit of a large number of system nodes. While our main motivation is considering eavesdroppers of unknown location, we first consider the case where the path-loss is identical between all pairs of nodes. In this case, a number of eavesdroppers that is exponential in the number of systems nodes can be tolerated. In the case of uniformly distributed eavesdroppers of unknown location, any number of eavesdroppers whose growth is sub-linear in the number of system nodes can be tolerated. The proposed approach significantly outperforms a power control approach based on standard multi-user diversity.
Autors: Goeckel, Dennis;Vasudevan, Sudarshan;Towsley, Don;Adams, Stephan;Ding, Z.;Leung, K.;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Dec 2011, volume: 29, issue:10, pages: 2067 - 2076
Publisher: IEEE
Full litterature document
 
» Assemble New Object Detector With Few Examples
Abstract:
Learning a satisfactory object detector generally requires sufficient training data to cover the most variations of the object. In this paper, we show that the performance of object detector is severely degraded when training examples are limited. We propose an approach to handle this issue by exploring a set of pretrained auxiliary detectors for other categories. By mining the global and local relationships between the target object category and auxiliary objects, a robust detector can be learned with very few training examples. We adopt the deformable part model proposed by Felzenszwalb and simultaneously explore the root and part filters in the auxiliary object detectors under the guidance of the few training examples from the target object category. An iterative solution is introduced for such a process. The extensive experiments on the PASCAL VOC 2007 challenge data set show the encouraging performance of the new detector assembled from those related auxiliary detectors.
Autors: Yang, K.;Wang, M.;Hua, X.-S.;Yan, S.;Zhang, H.-J.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Dec 2011, volume: 20, issue:12, pages: 3341 - 3349
Publisher: IEEE
Full litterature document
 
» Assessing the proximity of time evolutions through dynamic time warping
Abstract:
Comparing time-series is a frequent task in many scientific fields. In power systems, in particular, it may be of interest to compare the outputs of a simplified and a detailed model, or to validate the output of a model with respect to a measured time response. The classical Euclidean distance, involving pairs of points of the two data series aligned in time, is not suited to the practical time evolutions met in power systems, which often involve variable time delays and jumps at discrete times. In this study, an alternative measure of proximity, stemming from other scientific fields, is proposed for power system applications. It consists in warping the time axis to guarantee the best match between the two time-series, that is it maps points on two curves that are not aligned in time so as to minimise the sum of squared differences of their ordinates. Modifications and adaptations of the classical algorithm to better fit power system problems are discussed. The method is illustrated through three representative curve comparison problems. A multi-dimensional extension allowing system-wide measures of similarity is also proposed.
Autors: Fabozzi, D.;Cutsem, T.V.;
Appeared in: IET Generation, Transmission & Distribution
Publication date: Dec 2011, volume: 5, issue:12, pages: 1268 - 1276
Publisher: IEEE
Full litterature document
 
» Assessing the Vulnerability of the Fiber Infrastructure to Disasters
Abstract:
Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to physical attacks, such as an electromagnetic pulse (EMP) attack. Such real-world events happen in specific geographical locations and disrupt specific parts of the network. Therefore, the geographical layout of the network determines the impact of such events on the network's connectivity. In this paper, we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the most vulnerable parts of the network. That is, the locations of disasters that would have the maximum disruptive effect on the network in terms of capacity and connectivity. We consider graph models in which nodes and links are geographically located on a plane. First, we consider a simplistic bipartite graph model and present a polynomial-time algorithm for finding a worst-case vertical line segment cut. We then generalize the network model to graphs with nodes at arbitrary locations. We model the disaster event as a line segment or a disk and develop polynomial-time algorithms that find a worst-case line segment cut and a worst-case circular cut. Finally, we obtain numerical results for a specific backbone network, thereby demonstrating the applicability of our algorithms to real-world networks. Our novel approach provides a promising new direction for network design to avert geographical disasters or attacks.
Autors: Neumayer, S.;Zussman, G.;Cohen, R.;Modiano, E.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Dec 2011, volume: 19, issue:6, pages: 1610 - 1623
Publisher: IEEE
Full litterature document
 
» Assessment of an Inverse Algorithm for Cylinders Localization
Abstract:
We examine how an algorithm for localizing cylinders of arbitrary known radius is affected by errors in the radius knowledge. Reflection mode multi-frequency multi-bistatic configuration is considered. The problem is first examined in far zone, where analytical results can be found. Then, numerical results for the near zone case are provided and a procedure to estimate the cylinder's radius, if it is not known, is introduced. The expected behavior is tested against simulated and experimental data for both perfectly electrical conducting and dielectric cylinders embedded into a lossless homogeneous background. Numerical results of localization of objects embedded into a lossy half space are also shown.
Autors: Brancaccio, A.;Di Dio, C.;Leone, G.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Dec 2011, volume: 4, issue:4, pages: 754 - 762
Publisher: IEEE
Full litterature document
 
» Assessment of structure variation in silicon nanowire FETs and impact on SRAM
Abstract:
Impact of device structure variability of silicon nanowire FETs is assessed and SRAM design implication is presented based on 3-D numerical simulation. Both the conventional and junctionless nanowire FETs are shown to be sensitive to structural variation whereas the former is more tolerable. Both the circular wire and non-circular wire cases for feasible SRAM design with a focus on read/write noise margin are included in our study.
Autors: Yi-Bo Liao, Meng-Hsueh Chiang, Keunwoo Kim, Wei-Chou Hsu
Appeared in: Microelectronics Journal
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Assistive mobility devices focusing on Smart Walkers: classification and review
Abstract:

Highlights

? Mobility assitive devices ? Smart Walkers ? Classification and review of Smart Walkers


Autors: In an aging society it is extremely important to develop devices, which can support and aid the elderly in their daily life. This demands means and tools that extend independent living and promote improved health.Thus, the goal of this article is to
Appeared in: Robotics and Autonomous Systems
Publication date: Dec 2011
Publisher: Elsevier B.V.
Full litterature document
 
» Assuring the Future? A Look at Validating Climate Model Software
Abstract:
The scientific community studying climate change uses a variety of strategies to assess the correctness of climate models. These software systems represent large, sophisticated, fine-grained scientific tools. The validation practices described are thus tailored to a domain in which software and software engineering practices are useful but cannot be allowed to get in the way of the science.
Autors: Shull, Forrest;
Appeared in: IEEE Software
Publication date: Dec 2011, volume: 28, issue:6, pages: 4 - 8
Publisher: IEEE
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» Asymmetric Design and Simulation of Ring-Defect Photonic Crystal Vertical-Cavity Surface-Emitting Lasers
Abstract:
In this letter, the optical modes of a ring-defect photonic crystal vertical-cavity surface-emitting laser are calculated by the fully numerical solution of the scalar Helmholtz equation. We explain the experimentally observed higher order mode emission on the basis of optical loss discrimination. Special photonic crystal patterns that favor even higher order optical modes are designed and simulated. These modes are beyond the scope of previous simplified analysis.Pub _bookmark Command="[Quick Mark]"
Autors: Nyakas, P.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Dec 2011, volume: 23, issue:24, pages: 1869 - 1871
Publisher: IEEE
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» Asymmetrically Doped FinFETs for Low-Power Robust SRAMs
Abstract:
We propose FinFETs with unequal source and drain doping concentrations [asymmetrically doped (AD) FinFETs] for low-power robust SRAMs. The effect of asymmetric source/drain doping on the device characteristics is extensively analyzed, and the key differences between conventional and AD FinFETs are clearly shown. We show that asymmetry in the device structure leads to unequal currents for positive and negative drain biases, which is exploited to achieve mitigation of read–write conflict in 6T SRAMs. The proposed device exhibits superior short-channel characteristics compared to a conventional FinFET due to reduced electric fields from the terminal that has a lower doping. This results in significantly lower cell leakage in AD-FinFET-based 6T SRAM. Compared to the conventional FinFET-based 6T SRAM, AD-FinFET SRAM shows 5.2%–8.3% improvement in read static noise margin (SNM), 4.1%–10.2% higher write margin, 4.1%–8.8% lower write time, 1.3%–3.5% higher hold SNM, and 2.1–2.5 lower cell leakage at the cost of 20%–23% higher access time. There is no area penalty associated with the proposed technique.
Autors: Moradi, F.;Gupta, S. K.;Panagopoulos, G.;Wisland, D. T.;Mahmoodi, H.;Roy, K.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Dec 2011, volume: 58, issue:12, pages: 4241 - 4249
Publisher: IEEE
Full litterature document
 
» Asynchronous Output-Feedback Control of Networked Nonlinear Systems With Multiple Packet Dropouts: T–S Fuzzy Affine Model-Based Approach
Abstract:
This paper investigates the problem of robust output-feedback control for a class of networked nonlinear systems with multiple packet dropouts. The nonlinear plant is represented by Takagi–Sugeno (T–S) fuzzy affine dynamic models with norm-bounded uncertainties, and stochastic variables that satisfy the Bernoulli random binary distribution are adopted to characterize the data-missing phenomenon. The objective is to design an admissible output-feedback controller that guarantees the stochastic stability of the resulting closed-loop system with a prescribed disturbance attenuation level. It is assumed that the plant premise variables, which are often the state variables or their functions, are not measurable so that the controller implementation with state-space partition may not be synchronous with the state trajectories of the plant. Based on a piecewise quadratic Lyapunov function combined with an S-procedure and some matrix inequality convexifying techniques, two different approaches to robust output-feedback controller design are developed for the underlying T–S fuzzy affine systems with unreliable communication links. The solutions to the problem are formulated in the form of linear matrix inequalities (LMIs). Finally, simulation examples are provided to illustrate the effectiveness of the proposed approaches.
Autors: Qiu, J.;Feng, G.;Gao, H.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Dec 2011, volume: 19, issue:6, pages: 1014 - 1030
Publisher: IEEE
Full litterature document
 
» Atmospheric Pressure
Abstract:
This article focuses on the latest trends and enhancements emerging in system operations as wind penetrations grow. We discuss technical improvements, current and pending market changes for very high levels of variable generation, the value of forecasting improvements, and the collaborative work that may lead to improved forecasting. This is work at the cutting edge, gathering the latest examples that the authors believe to be of special interest, and we expect this area to remain vibrant and dynamic for many years to come.
Autors: Ahlstrom, M.;Blatchford, J.;Davis, M.;Duchesne, J.;Edelson, D.;Focken, U.;Lew, D.;Loutan, C.;Maggio, D.;Marquis, M.;McMullen, M.;Parks, K.;Schuyler, K.;Sharp, J.;Souder, D.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Dec 2011, volume: 9, issue:6, pages: 97 - 107
Publisher: IEEE
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» Atmospheric-Pressure Reverse-Vortex Microwave Plasma Torch
Abstract:
In this paper, the authors present the results of recent developments and experimental investigations of a new atmospheric-pressure microwave plasma torch with reverse-vortex plasma stabilization and different plasma gases, such as air and nitrogen. Such a torch could be used for a variety of applications, for example, nitriding of steel and alloy surface, new materials and nanopowder production, ignition and flame control, coating, etching, and some other materials processing.
Autors: Lavrov, B. P.;Lavrov, P. B.;Ravaev, A. A.;Esakov, I. I.;Matveev, I. B.;Kirchuk, E. Y.;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Dec 2011, volume: 39, issue:12, pages: 3314 - 3318
Publisher: IEEE
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» Attitude and orbit control systems for the LISA Pathfinder mission
Abstract:
The main purpose of the LISA Pathfinder mission is to provide in-orbit validation of the critical technologies necessary for LISA (Laser Interferometer Space Antenna), aiming at detecting gravitational waves generated by very massive objects such as black holes. The spacecraft consists of a Science Module (SCM) and a propulsion module (PRM). The former performs the science experiment, and the later provides the propulsive capability to raise the spacecraft from the injection orbit to the operational orbit at around L1 and is then separated from the former. The Spacecraft Attitude and Orbit Control System (AOCS) is actually composed of three distinct systems to fulfill the needs of the whole mission: - Composite AOCS, used to reach L1, aims at raising the Perigee through a succession of about 10 boosts performed with high thrust chemical propulsion; - Micro-Propulsion AOCS takes over once the separation of the SCM from PRM has occurred and is based on micro-propulsion systems (micro-Newton electrical thrusters); -Drag-Free Attitude Control System (DFACS) is then used to perform science experiments. This article provides a comprehensive overview of the AOCS architecture, requirements, selected sensors and actusators, system design & evolution, and achieved performances. It focuses in particular on the Composite AOCS and the Micro-propulsion AOCS and will analyze the challenges of using micro-Newton electric propulsion.
Autors: Luisella Giulicchi, Shu-Fan Wu, Thomas Fenal
Appeared in: Aerospace Science and Technology
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Attitude control of magnetically actuated satellites with an uneven inertia distribution
Abstract:
This paper addresses magnetic attitude control of a satellite with one axis of inertia significantly lower than that of the other two. With onboard resources often limited, this paper considers the development of an effective control strategy that remains easy to implement. Often used in this type of application, the classical 'torque-projection' approach is shown to be unsuitable for satellites with an uneven inertia distribution. To tackle the weaknesses in this approach a new 'weighted' PD approach is proposed, with the control torque determined through minimization of a simple cost function. Through a similar philosophy, a feed-forward compensator is designed to supplement the feedback control and improve the disturbance rejection characteristics of the controller. Floquet analysis is used to verify stability of the control strategy for the nominal case and satellites with uncertainties. Simulations carried out on a high fidelity model demonstrate the effectiveness of the proposed control law and the significant performance benefits offered over existing approaches.
Autors: Mark Wood, Wen-Hua Chen
Appeared in: Aerospace Science and Technology
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Au?Auinteraction induced semiconducting microwires with photo- and vapor-responsive properties
Abstract:
image

Highlights

? Au3A3microwires were assembled based on intermolecular Au?Auinteractions. ? We fabricated organic field-effect transistor (OFET) devices with the wires. ? The microwires devices exhibited high hole mobility (0.23 cm V s). ? The microwires showed vapor-/photo-switchable conductive characteristics.

Autors:

Graphical abstract

Appeared in: Organic Electronics
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Augmented Lagrangian Approach to Design of Structured Optimal State Feedback Gains
Abstract:
We consider the design of optimal state feedback gains subject to structural constraints on the distributed controllers. These constraints are in the form of sparsity requirements for the feedback matrix, implying that each controller has access to information from only a limited number of subsystems. The minimizer of this constrained optimal control problem is sought using the augmented Lagrangian method. Notably, this approach does not require a stabilizing structured gain to initialize the optimization algorithm. Motivated by the structure of the necessary conditions for optimality of the augmented Lagrangian, we develop an alternating descent method to determine the structured optimal gain. We also utilize the sensitivity interpretation of the Lagrange multiplier to identify favorable communication architectures for structured optimal design. Examples are provided to illustrate the effectiveness of the developed method.
Autors: Lin, F.;Fardad, M.;Jovanovic, M. R.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Dec 2011, volume: 56, issue:12, pages: 2923 - 2929
Publisher: IEEE
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» Automated Segmentation Refinement of Small Lung Nodules in CT Scans by Local Shape Analysis
Abstract:
One of the most important problems in the segmentation of lung nodules in CT imaging arises from possible attachments occurring between nodules and other lung structures, such as vessels or pleura. In this report, we address the problem of vessels attachments by proposing an automated correction method applied to an initial rough segmentation of the lung nodule. The method is based on a local shape analysis of the initial segmentation making use of 3-D geodesic distance map representations. The correction method has the advantage that it locally refines the nodule segmentation along recognized vessel attachments only, without modifying the nodule boundary elsewhere. The method was tested using a simple initial rough segmentation, obtained by a fixed image thresholding. The validation of the complete segmentation algorithm was carried out on small lung nodules, identified in the ITALUNG screening trial and on small nodules of the lung image database consortium (LIDC) dataset. In fully automated mode, 217/256 (84.8%) lung nodules of ITALUNG and 139/157 (88.5%) individual marks of lung nodules of LIDC were correctly outlined and an excellent reproducibility was also observed. By using an additional interactive mode, based on a controlled manual interaction, 233/256 (91.0%) lung nodules of ITALUNG and 144/157 (91.7%) individual marks of lung nodules of LIDC were overall correctly segmented. The proposed correction method could also be usefully applied to any existent nodule segmentation algorithm for improving the segmentation quality of juxta-vascular nodules.
Autors: Diciotti, S.;Lombardo, S.;Falchini, M.;Picozzi, G.;Mascalchi, M.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Dec 2011, volume: 58, issue:12, pages: 3418 - 3428
Publisher: IEEE
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» Automatic classification of cells and intercellular spaces of apple tissue
Abstract:

Highlights

? Cells and intercellular spaces can be characterized by their size and shape. ? Classification by means of LDA enables to process a large number of images. ? Examined varieties of apples require individual classification functions.


Autors: A procedure was developed for the automatic identification of cells and intercellular spaces of apple tissue from microscopic images. Two cultivars were used to develop the method: 'Golden Delicious' and 'Champion'. Images of tissue microstructure we
Appeared in: Computers and Electronics in Agriculture
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Automatic control for a miniature manipulator based on 3D vision servo of soft objects
Abstract:
This paper presents a new strategy for automating three-dimensional miniaturized manipulators using a visual feedback. This automation scheme can be used to handle the challenges associated with manipulation of minute soft components such as biological entities. The developed vision control system combines a depth and planar motion control using a single camera and an auto focus algorithm. This visual process was conducted by applying image segmentation and probe recognition along with depth alignment. To demonstrate the feasibility, reliability and robustness of this newly proposed strategy, extensive computer simulations were performed on images of a Zyvex® nanomanipulator obtained using a Scanning Electron Microscope (SEM). Also, a prototype manipulator with a visual feedback and an automatic controller was constructed and tested using soft elements. The results showed good accuracy and robustness of the end-effector recognition, positioning and aligning without occlusion difficulties.
Autors: Mohammad Abdel Kareem Jaradat, Mohamed Al-Fandi, Mohammad Tariq Nasir
Appeared in: Mechatronics
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Automatic Feature Extraction and Text Recognition From Scanned Topographic Maps
Abstract:
A system for automatic extraction of various feature layers and recognition of the text content of scanned topographic maps is presented here. Linear features which are often intersecting with the text are first extracted using a novel line representation method and a set of directional morphological operations. Other graphical objects are then removed in several stages to obtain a text-only image. A custom defect model is subsequently used to create an artificial training set for a Hidden Markov Model-based character recognition engine. Finally, the recovered text is recognized using this multifont segmentation-free optical character recognition (OCR). Extensive testing is conducted to assess the performance of different stages of the proposed system. Furthermore, our custom OCR is shown to achieve a 94% recognition rate for the extracted text, thereby outperforming a commercial OCR used as a benchmark.
Autors: Pezeshk, A.;Tutwiler, R. L.;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Dec 2011, volume: 49, issue:12, pages: 5047 - 5063
Publisher: IEEE
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» Automatic Identification of Functional Clusters in fMRI Data Using Spatial Dependence
Abstract:
In independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data, extracting a large number of maximally independent components provides a detailed functional segmentation of brain. However, such high-order segmentation does not establish the relationships among different brain networks, and also studying and classifying components can be challenging. In this study, we present a multidimensional ICA (MICA) scheme to achieve automatic component clustering. In our MICA framework, stable components are hierarchically grouped into clusters based on higher order statistical dependence—mutual information—among spatial components, instead of the typically used temporal correlation among time courses. The final cluster membership is determined using a statistical hypothesis testing method. Since ICA decomposition takes into account the modulation of the spatial maps, i.e., temporal information, our ICA-based approach incorporates both spatial and temporal information effectively. Our experimental results from both simulated and real fMRI datasets show that the use of spatial dependence leads to physiologically meaningful connectivity structure of brain networks, which is consistently identified across various ICA model orders and algorithms. In addition, we observe that components related to artifacts, including cerebrospinal fluid, arteries, and large draining veins, are grouped together and encouragingly distinguished from other components of interest.
Autors: Ma, S.;Correa, N. M.;Li, X-.L.;Eichele, T.;Calhoun, V. D.;Adali, T.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Dec 2011, volume: 58, issue:12, pages: 3406 - 3417
Publisher: IEEE
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» Automatic Image Segmentation by Dynamic Region Merging
Abstract:
This paper addresses the automatic image segmentation problem in a region merging style. With an initially oversegmented image, in which many regions (or superpixels) with homogeneous color are detected, an image segmentation is performed by iteratively merging the regions according to a statistical test. There are two essential issues in a region-merging algorithm: order of merging and the stopping criterion. In the proposed algorithm, these two issues are solved by a novel predicate, which is defined by the sequential probability ratio test and the minimal cost criterion. Starting from an oversegmented image, neighboring regions are progressively merged if there is an evidence for merging according to this predicate. We show that the merging order follows the principle of dynamic programming. This formulates the image segmentation as an inference problem, where the final segmentation is established based on the observed image. We also prove that the produced segmentation satisfies certain global properties. In addition, a faster algorithm is developed to accelerate the region-merging process, which maintains a nearest neighbor graph in each iteration. Experiments on real natural images are conducted to demonstrate the performance of the proposed dynamic region-merging algorithm.
Autors: Peng, B.;Zhang, L.;Zhang, D.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Dec 2011, volume: 20, issue:12, pages: 3592 - 3605
Publisher: IEEE
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» Automatic recognition vision system guided for apple harvesting robot
Abstract:
image

Highlights

? An automatic recognition vision system guided for apple harvesting robot is presented. ? The region growing method and color feature is employed to develop an image segmentation algorithm. ? A classification algorithm based on support vector machine for apple recognition is developed. ? Apple recognition success rate is 89%, and the average recognition time is 352 ms.

Autors:

Graphical abstract

Appeared in: Computers & Electrical Engineering
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Automatic Segmentation of Multi-Beam Data for Predictive Mapping of Benthic Habitats on the Chella Seamount (North-Eastern Alboran Sea, Western Mediterranean)
Abstract:
A reliable and objective classification method has been produced for the differentiation of benthic habitats in the seamount regions of the North-Eastern Alboran Sea. Acoustic backscatter and depth measurements from multi-beam data are automatically fused and then classified using video transects of known cold-water coral ecosystems as ground-truth. Results of the classification reveal the locations of potentially similar habitats in the region, and could be used as a base map for the planning of future scientific campaigns in the area.
Autors: Coiras, E.;Lo Iacono, C.;Gracia, E.;Danobeitia, J.;Sanz, J. L.;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Dec 2011, volume: 4, issue:4, pages: 809 - 813
Publisher: IEEE
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» Automotive Shift
Abstract:
Analytical calculation formulations based on the Coulombia model are presented in this article. These formulations are easily recognized by a computer. The results of tests and experiments confirmed their validity.
Autors: Zhou, X.;Sun, W.;Zhao, G.;Wang, Y.;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Dec 2011, volume: 6, issue:4, pages: 68 - 73
Publisher: IEEE
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» Average Cost Optimality in Inventory Models With Dynamic Information Delays
Abstract:
Information delays exist when the most recent inventory information available to the Inventory Manager (IM) is dated. In other words, the IM observes only the inventory level that belongs to an earlier period. Such situations are not uncommon, and they arise when it takes a while to process the demand data and pass the results to the IM. In this paper, we establish that the average cost optimal policy is of state-dependent basestock type with respect to the reference inventory position. We show that the optimal base stock depends on the age and the magnitude of the latest observed delay. We illustrate the results by solving an example with delays of 0 and 1, for which we are able to obtain formulas/bounds for the basestock levels.
Autors: Bensoussan, A.;Cakanyildirim, M.;Sethi, S. P.;Wang, M.;Zhang, H.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Dec 2011, volume: 56, issue:12, pages: 2869 - 2882
Publisher: IEEE
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» Back to Thin-Core Massively Parallel Processors
Abstract:
Examination of the innovations of the past three decades that brought chips to the point at which many-core processors are possible reveals that there are multiple roads ahead, and each is full of challenges.
Autors: Marowka, Ami;
Appeared in: Computer
Publication date: Dec 2011, volume: 44, issue:12, pages: 49 - 54
Publisher: IEEE
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» Background Foreground Segmentation for SLAM
Abstract:
To perform simultaneous localization and mapping (SLAM) in dynamic environments, static background objects must first be determined. This condition can be achieved using a priori information in the form of a map of background objects. Such an approach exhibits a causality dilemma, because such a priori information is the ultimate goal of SLAM. In this paper, we propose a background foreground segmentation method that overcomes this issue. Localization is achieved using a robust iterative closest point implementation and vehicle odometry. Background objects are modeled as objects that are consistently located at a given spatial location. To improve robustness, classification is performed at the object level through the integration of a new segmentation method that is robust to partial object occlusion.
Autors: Corcoran, P.;Winstanley, A.;Mooney, P.;Middleton, R.;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Dec 2011, volume: 12, issue:4, pages: 1177 - 1183
Publisher: IEEE
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» Balanced Multiple Description Coding for 3D DCT Video
Abstract:
We propose a balanced multiple description coding framework using rate-distortion splitting for three dimensional DCT (3D DCT) coded video data. The proposed algorithm produces correlated and balanced descriptions, with balancing in terms of bit rate and receiver distortion. Our description splitting and balancing algorithm takes advantage of the structural properties of the 3D DCT video volume and the method of shifted compliment hyperboloid used in scanning and quantization of 3D DCT coefficients. Given the available bit rate and redundancy our simulations show high PSNR values for the reconstructed video. The proposed video codec requires a simple implementation, has a low complexity, and produces a high reconstruction quality. Comparative results with other schemes are included.
Autors: Sawant, S.;Adjeroh, D. A.;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Dec 2011, volume: 57, issue:4, pages: 765 - 776
Publisher: IEEE
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» Balancing Act
Abstract:
The paper presents the functions of the Integration of Variable Generation Task Force (IVGTF) created by the planning and operating committees of the North American Electric Reliability Corporation (NERC) in 2008. This is in anticipation of the substantial growth of renewable variable generation such as wind and solar resources.
Autors: Lauby, M.G.;Ahlstrom, M.;Brooks, D.L.;Beuning, S.;Caspary, J.;Grant, W.;Kirby, B.;Milligan, M.;O'Malley, M.;Patel, M.;Piwko, R.;Pourbeik, P.;Shirmohammadi, D.;Smith, J.C.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Dec 2011, volume: 9, issue:6, pages: 75 - 85
Publisher: IEEE
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» Balancing Attended and Global Stimuli in Perceived Video Quality Assessment
Abstract:
The visual attention mechanism plays a key role in the human perception system and it has a significant impact on our assessment of perceived video quality. In spite of receiving less attention from the viewers, unattended stimuli can still contribute to the understanding of the visual content. This paper proposes a quality model based on the late attention selection theory, assuming that the video quality is perceived via two mechanisms: global and local quality assessment. First we model several visual features influencing the visual attention in quality assessment scenarios to derive an attention map using appropriate fusion techniques. The global quality assessment as based on the assumption that viewers allocate their attention equally to the entire visual scene, is modeled by four carefully designed quality features. By employing these same quality features, the local quality model tuned by the attention map considers the degradations on the significantly attended stimuli. To generate the overall video quality score, global and local quality features are combined by a content adaptive linear fusion method and pooled over time, taking the temporal quality variation into consideration. The experimental results have been compared to results from appropriate eye tracking and video quality assessment experiments, demonstrating promising performance.
Autors: You, J.;Korhonen, J.;Perkis, A.;Ebrahimi, T.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Dec 2011, volume: 13, issue:6, pages: 1269 - 1285
Publisher: IEEE
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» Band-gap narrowing in α-(CrxFe1-x)2O3 solid-solution films
Abstract:
We report on structural and optical properties for the (0001)-oriented α-(CrxFe1-x)2O3 (0 ≤ x ≤ 1) epitaxial films prepared on c-sapphire substrates by using pulsed-laser deposition. Pure corundum phase with atomically flat surface was obtained in the entire composition range. Optical absorption spectra for the films with 0.2 < x < 0.9 showed a nearly constant band-gap (1.7 eV), which is narrower than those of α-Fe2O3 (2.1 eV) and α-Cr2O3 (3.0 eV). The result suggests that the band-gap narrowing arises from a type-II band alignment of these oxides and the fundamental band-gap lies between the Cr t2g and O 2p occupied states and the Fe t2g* empty state.
Autors: Mashiko, Hisanori;Oshima, Takayoshi;Ohtomo, Akira;
Appeared in: Applied Physics Letters
Publication date: Dec 2011, volume: 99, issue:24, pages: 241904 - 241904-3
Publisher: IEEE
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» Bandwidth Analysis of Waveguide Mode Converters Based on Optical Analogy of Stimulated Raman Adiabatic Passage in Engineered Multimode Waveguides
Abstract:
Mode conversion can be achieved in multimode waveguides using optical analogy of stimulated Raman adiabatic passage. The coupled mode equations (CMEs) for adiabatic mode conversion via an intermediate mode with wavelength detunings are derived for an engineered step-index multimode waveguide. It is shown that the detunings cause diabatic coupling of adiabatic modes and result in lowered conversion efficiency. The Landau–Zener (LZ) model of nonadiabatic crossing is used to analyze the spectral response of the mode converters and shown to be in good agreement with numerical solutions of the CMEs and beam propagation simulations. The analytical expressions from the LZ analysis offer useful insight into the spectral properties of the mode converters and suggest bandwidth tunability of these devices. We demonstrate bandwidth tunability of the mode converter by a numerical example.
Autors: Hsiao, F.-C.;Lin, T.-Y.;Tseng, S.-Y.;
Appeared in: IEEE Photonics Journal
Publication date: Dec 2011, volume: 3, issue:6, pages: 1198 - 1205
Publisher: IEEE
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» Bayesian neural networks for the prediction of stochastic travel times in urban networks
Abstract:
Urban travel time prediction has received much less attention than predictions on freeways, perhaps because urban travel times show much larger variations and are therefore much harder to predict. However, urban travel time can form a substantial part of the total travel time of a road user and therefore effort should be taken to predict urban travel times. In this study, neural networks are used for urban travel time prediction because these have shown to be able to deal with noisy data. Bayesian techniques are used for training of the networks, resulting in committees with lower error and in confidence bounds. It is shown that the neural network committees are capable of predicting the `low-frequency trend??, which can be seen when the high-frequency component of travel time is removed using de-noising. The errors of the predictions on the low-frequency trend are in the same order as when predicting freeway travel times, and it is shown that the predicted confidence bounds are accurate.
Autors: Hinsbergen, C.P.I.J.V.;Hegyi, A.;Lint, J.W.C.V.;Zuylen, H.J.V.;
Appeared in: IET Intelligent Transport Systems
Publication date: Dec 2011, volume: 5, issue:4, pages: 259 - 265
Publisher: IEEE
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» Bayesian Robust Principal Component Analysis
Abstract:
A hierarchical Bayesian model is considered for decomposing a matrix into low-rank and sparse components, assuming the observed matrix is a superposition of the two. The matrix is assumed noisy, with unknown and possibly non-stationary noise statistics. The Bayesian framework infers an approximate representation for the noise statistics while simultaneously inferring the low-rank and sparse-outlier contributions; the model is robust to a broad range of noise levels, without having to change model hyperparameter settings. In addition, the Bayesian framework allows exploitation of additional structure in the matrix. For example, in video applications each row (or column) corresponds to a video frame, and we introduce a Markov dependency between consecutive rows in the matrix (corresponding to consecutive frames in the video). The properties of this Markov process are also inferred based on the observed matrix, while simultaneously denoising and recovering the low-rank and sparse components. We compare the Bayesian model to a state-of-the-art optimization-based implementation of robust PCA; considering several examples, we demonstrate competitive performance of the proposed model.
Autors: Ding, X.;He, L.;Carin, L.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Dec 2011, volume: 20, issue:12, pages: 3419 - 3430
Publisher: IEEE
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» Beam Properties of Visible Proton-Implanted Photonic Crystal VCSELs
Abstract:
We investigate the optical properties of proton-implanted photonic crystal (PhC) vertical-cavity surface-emitting lasers (VCSELs) emitting in the visible spectrum. The fabricated lasers have a threshold current of 1.3 mA and single-mode output power greater than 1 mW at room temperature. The incorporation of a PhC into the top facet of a proton-implanted VCSEL results in a stable single-fundamental-mode operation with a side-mode suppression ratio larger than 30 dB and a constant beam divergence independent of injection current level or ambient temperature. Using an index-step optical fiber model, we compare the effects of different hole etching depths to variations in output beam divergence. By varying the design and etching depth of the hole pattern, the lasers can either be optimized for low beam divergence or low threshold currents. The controllable refractive index guidance effect from the PhC allows for precise engineering of the optical properties of these visible VCSELs for consumer and imaging applications.
Autors: Kasten, A. M.;Siriani, D. F.;Hibbs-Brenner, M. K.;Johnson, K. L.;Choquette, K. D.;
Appeared in: IEEE Journal of Selected Topics in Quantum Electronics
Publication date: Dec 2011, volume: 17, issue:6, pages: 1648 - 1655
Publisher: IEEE
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» Behavior of triple-gate Bulk FinFETs with and without DTMOS operation
Abstract:

Highlights

? Dynamic Threshold (DT) voltage technique in triple-gate FinFETs. ? Standard Bulk FinFETs and Bulk FinFETs under DTMOS operation. ? DTMOS technique is a good alternative to standard low-power low-voltage devices. ? DTMOS technique advantage is due to its ability to adjust the threshold voltage. ? In DTMOS operation, the back gate plays the role of an additional gate.


Autors: In this paper, the combination of the Dynamic Threshold (DT) voltage technique with a non-planar structure is experimentally studied in triple-gate FinFETs. The drain current, transconductance, resistance, threshold voltage, subthreshold swing and Dr
Appeared in: Solid-State Electronics
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Belief Propagation for Distributed Downlink Beamforming in Cooperative MIMO Cellular Networks
Abstract:
We propose a new graphical model approach to cooperative multiple-input multiple-output (MIMO) cellular networks. The objective is to optimize downlink transmit beamforming at each BS in order to maximize the sum throughput over the entire network. While ideal centralized beamforming requires full channel state information (CSI) sharing among all BSs in the network and huge computational complexity for combinatorial optimization, the proposed graphical model enables distributed beamforming which requires only local CSI sharing between neighboring BSs and efficiently solves the optimization problem in a distributed manner. As distributed solvers for this problem, we derive message-passing algorithms which can be implemented with polynomial-time computational complexity. Furthermore, we make a slight approximation on the objective function to derive a simpler graphical model, providing further complexity saving. Simulation results indicate that the proposed distributed downlink beamforming achieves average cell throughput typically within just 2% of ideal centralized beamforming.
Autors: Sohn, Illsoo;Lee, Sang Hyun;Andrews, Jeffrey G.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Dec 2011, volume: 10, issue:12, pages: 4140 - 4149
Publisher: IEEE
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» Benefit of exercise therapy for systolic heart failure in relation to disease severity and etiology--findings from the Heart Failure and A Controlled Trial Investigating Outcomes of Exercise Training study
Abstract:
BackgroundThis post hoc analysis of the HF-ACTION cohort explores the primary and secondary results of the HF-ACTION study by etiology and severity of illness.MethodsHF-ACTION randomized stable outpatients with reduced left ventricular (LV) function and heart failure (HF) symptoms to either supervised exercise training plus usual care or to usual care alone. The primary outcome was all-cause mortality or all-cause hospitalization; secondary outcomes included all-cause mortality, cardiovascular mortality or cardiovascular hospitalization, and cardiovascular mortality or HF hospitalization. The interaction between treatment and risk variable, etiology or severity as determined by risk score, New York Heart Association class, and duration of cardiopulmonary exercise test was examined in a Cox proportional hazards model for all clinical end points.ResultsThere was no interaction between etiology and treatment for the primary outcome (P= .73), cardiovascular (CV) mortality or CV hospitalization (P= .59), or CV mortality or HF hospitalization (P= .07). There was a significant interaction between etiology and treatment for the outcome of mortality (P= .03), but the interaction was no longer significant when adjusted for HF-ACTION adjustment model predictors (P= .08). There was no significant interaction between treatment effect and severity, except a significant interaction between cardiopulmonary exercise duration and training was identified for the primary outcome of all-cause mortality or all-cause hospitalization.ConclusionConsideration of symptomatic (New York Heart Association classes II to IV) patients with HF with reduced LV function for participation in an exercise training program should be made independent of the cause of HF or the severity of the symptoms.
Autors: David J. Whellan, Anil Nigam, Malcolm Arnold, Aijing Z. Starr, James Hill, ...
Appeared in: International Journal of Electrical Power & Energy Systems
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Benefits of Human–Robot Interaction [TC Spotlight]
Abstract:
Autors: Salvine, P.;Nicolescu, M.;Ishiguro, H.;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Dec 2011, volume: 18, issue:4, pages: 98 - 99
Publisher: IEEE
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» Beyond Simon's Slice: Five Fundamental Trade-Offs that Bound the Performance of Macrocognitive Work Systems
Abstract:
Macrocognitive work systems are complex adaptive systems designed to support near-continuous interdependencies among humans and intelligent machines to carry out joint cognitive work that includes functions such as sensemaking, replanning, mental projection to the future, and coordination. The effort to identify empirical laws and use them to construct a formal theory led the authors to the identification of fundamental trade-offs that place performance limits on all macrocognitive work systems. This article presents five trade-offs that define these limits. It also illustrates how empirical regularities about the performance of human work systems emerge from the trade-offs.
Autors: Hoffman, Robert R.;Woods, David D.;
Appeared in: IEEE Intelligent Systems
Publication date: Dec 2011, volume: 26, issue:6, pages: 67 - 71
Publisher: IEEE
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» Big Community in a Small World
Abstract:
With today's technology, people rarely give a second thought to connecting with others all over the world. On line networking sites such as Facebook, MySpace, and LinkedIn allow us to reach out to long-lost friends, meet new people, and develop important professional relationships. A popular tool for this global communication is the virtual world. A virtual world is a computer-based simulated environment where users create an online identity, appropriately called an avatar (defined as embodiment or personification long before it was used for computer games and communities), and use it to explore, create, and communicate with others. With more than 15 million users, Second Life (SL) is one of the most popular three-dimensional virtual worlds, with an interactive environment (referred to as inworld by its residents) that lends itself well to social networking, collaboration, and learning.
Autors: Nowicki, D.;
Appeared in: IEEE Potentials
Publication date: Dec 2011, volume: 30, issue:6, pages: 44 - 46
Publisher: IEEE
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» Birnbaum-Saunders Mixed Models for Censored Reliability Data Analysis
Abstract:
The Birnbaum-Saunders distribution is a useful model for describing fatigue and reliability data. This model allows us to relate the total time until the failure to some type of cumulative damage. The majority of the models based on the Birnbaum-Saunders distribution have assumed fixed-effects, and a few have been investigated for correlated data. In this work, we introduce Birnbaum-Saunders mixed models for censored data. Specifically, we estimate their parameters by means of the Gauss-Hermite quadrature approximation, carry out a residual analysis for these models, and conduct an application using real censored reliability data. This application illustrates the utility of a Birnbaum-Saunders random intercept model.
Autors: Villegas, C.;Paula, G. A.;Leiva, V.;
Appeared in: IEEE Transactions on Reliability
Publication date: Dec 2011, volume: 60, issue:4, pages: 748 - 758
Publisher: IEEE
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» Bisimilarity Enforcement for Discrete Event Systems Using Deterministic Control
Abstract:
For discrete event systems, the control to enforce bisimilarity with respect to a given specification has been studied in , , . In this note we consider the case when the control is required to be deterministic. While a deterministic control is restrictive compared to a nondeterministic one, the case of deterministic control has its own practical significance as it is easier to implement and computationally less expensive to verify. We provide a necessary and sufficient condition for the existence of a bisimilarity enforcing deterministic control, and discuss its computational complexity. We also study properties related to the synthesis of “subspecification” and “superspecification.”
Autors: Zhou, C.;Kumar, R.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Dec 2011, volume: 56, issue:12, pages: 2986 - 2991
Publisher: IEEE
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» Bismuth nano-droplets for group-V based molecular-beam droplet epitaxy
Abstract:
Self-assembly of bismuth droplets at nanoscale on GaAs(100) surface using molecular beam epitaxy was demonstrated. Fine control of density and size was achieved by varying growth temperature and total bismuth deposition. Droplet density was tuned by roughly 3 orders of magnitude, and the density-temperature dependence was found to be consistent with classical nucleation theory. These results may extend the flexibility of droplet epitaxy by serving as templates for group V based droplet epitaxy, which is in contrast to conventional group III based droplet epitaxy and may encourage nanostructure formation of bismuth-containing materials.
Autors: Li, C.;Zeng, Z. Q.;Fan, D. S.;Hirono, Y.;Wu, J.;Morgan, T. A.;Hu, X.;Yu, S. Q.;Wang, Zh. M.;Salamo, G. J.;
Appeared in: Applied Physics Letters
Publication date: Dec 2011, volume: 99, issue:24, pages: 243113 - 243113-3
Publisher: IEEE
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» Bistable Behavior Of Silicon Wafer In Rapid Thermal Processing Setup
Abstract:
image

Highlights

? The heat exchange mode between Si-wafer and the elements of the thermal reactor depends on the gas gap width b. ? The theoretical simulations predict the temperature bistability in the Si-wafer for low values of the gas gap. ? The bistability is observed for the gas gap width b=0.2 mm.

Autors:

Graphical abstract

Appeared in: Microelectronic Engineering
Publication date: Dec 2011
Publisher: Elsevier B.V.
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» Blind Equalizer for Constant-Modulus Signals based on Gaussian Process Regression
Abstract:
A new blind equalization method for constant modulus (CM) signals based on Gaussian process for regression (GPR) by incorporating a constant modulus algorithm (CMA)-like error function into the conventional GPR framework is proposed. The GPR framework formulates the posterior density function for weights by using Bayes' rule under the assumption of Gaussian prior for weights. The proposed blind GPR equalizer is based on linear-in-weights regression model which has a form of nonlinear minimum mean-square error solution. Simulation results in linear and nonlinear channels are presented in comparison with the state-of-the-art support vector machine (SVM) and relevance vector machine (RVM) based blind equalizers. The simulation results show that the proposed blind GPR equalizer without cumbersome cross-validation procedures shows the similar performances to the blind SVM and RVM equalizers in terms of intersymbol interference and bit error rate.
Autors: Kyuho Hwang, Sooyong Choi
Appeared in: Signal Processing
Publication date: Dec 2011
Publisher: Elsevier B.V.
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