﻿<?xml version="1.0" encoding="utf-8"?><rss version="2.0"><channel><title>Journal of Electrical and Computer Engineering</title><link>http://www.hindawi.com</link><description>The latest articles from Hindawi Publishing Corporation</description><copyright>&amp;#169; 2012, Hindawi Publishing Corporation. All rights reserved.</copyright><item><title>Minimum Symbol Error Probability MIMO Design under the Per-Antenna Power Constraint</title><link>http://www.hindawi.com/journals/jece/2012/290390/</link><description>Approximate minimum symbol error probability transceiver design of single user MIMO systems under the practical per-antenna power constraint is considered. The upper bound of a lower bound on the minimum distance between the symbol hypotheses is established. Necessary conditions and structures of the transmit covariance matrix for reaching the upper bound are discussed. Three numerical approaches (rank zero, rank one, and permutation) for obtaining the optimum precoder are proposed.  When the upper bound is reached, the resulting design is optimum. When the upper bound is not reached, a numerical fix is used. The approach is very simple and can be of practical use.</description><Author>Enoch Lu and I.-Tai Lu</Author><copyright>Copyright &amp;#xa9; 2012 Enoch Lu and I.-Tai Lu. All rights reserved.</copyright></item><item><title>Reduced Complexity Iterative Decoding of 3D-Product Block Codes Based on Genetic Algorithms</title><link>http://www.hindawi.com/journals/jece/2012/609650/</link><description>Two iterative decoding algorithms of 3D-product block codes (3D-PBC) based on genetic algorithms (GAs) are presented. The first algorithm uses the Chase-Pyndiah SISO, and the second one uses the list-based SISO decoding algorithm (LBDA) based on order-i reprocessing. We applied these algorithms over AWGN channel to symmetric 3D-PBC constructed from BCH codes. The simulation results show that the first algorithm outperforms the Chase-Pyndiah one and is only 1.38&amp;#x2009;dB away from the Shannon capacity limit at BER of 10&amp;#x2212;5 for BCH (31, 21, 5)3 and 1.4&amp;#x2009;dB for BCH (16, 11, 4)3. The simulations of the LBDA-based GA on the BCH (16, 11, 4)3 show that its performances outperform the first algorithm and is about 1.33&amp;#x2009;dB from the Shannon limit. Furthermore, these algorithms can be applied to any arbitrary 3D binary product block codes, without the need of a hard-in hard-out decoder. We show also that the two proposed decoders are less complex than both Chase-Pyndiah algorithm for codes with large correction capacity and LBDA for large i parameter. Those features make the decoders based on genetic algorithms efficient and attractive.</description><Author>Abdeslam Ahmadi, Faissal El Bouanani, Hussain Ben-Azza, and Youssef Benghabrit</Author><copyright>Copyright &amp;#xa9; 2012 Abdeslam Ahmadi et al. All rights reserved.</copyright></item><item><title>Analytical Model of a Weighted Round Robin Service System</title><link>http://www.hindawi.com/journals/jece/2012/374961/</link><description>This paper presents a mathematical description of Weighted Round Robin service strategy, on which basis all the perspective QoS tools that serve to manage congestion in converged packet networks work. On the basis of the presented mathematical model, it is possible to suitably configure the operational parameters (maximum queue length, distribution of the available transfer capacity) of these tools according to required values of packet delays. The implementation of the analytical model is demonstrated on a real network segment using advanced network data traffic emulator.</description><Author>Vladimir Hottmar and Bohumil Adamec</Author><copyright>Copyright &amp;#xa9; 2012 Vladimir Hottmar and Bohumil Adamec. All rights reserved.</copyright></item><item><title>Performance Evaluation of Data Compression Systems Applied to Satellite Imagery</title><link>http://www.hindawi.com/journals/jece/2012/471857/</link><description>Onboard image compression systems reduce the data storage and downlink bandwidth requirements in space missions. This paper presents an overview and evaluation of some compression algorithms suitable for remote sensing applications. Prediction-based compression systems, such as DPCM and JPEG-LS, and transform-based compression systems, such as CCSDS-IDC and JPEG-XR, were tested over twenty multispectral (5-band) images from CCD optical sensor of the CBERS-2B satellite. Performance evaluation of these algorithms was conducted using both quantitative rate-distortion measurements and subjective image quality analysis. The PSNR, MSSIM, and compression ratio results plotted in charts and the SSIM maps are used for comparison of quantitative performance. Broadly speaking, the lossless JPEG-LS outperforms other lossless compression schemes, and, for lossy compression, JPEG-XR can provide lower bit rate and better tradeoff between compression ratio and image quality.</description><Author>Lilian N. Faria, Leila M. G. Fonseca, and Max H. M. Costa</Author><copyright>Copyright &amp;#xa9; 2012 Lilian N. Faria et al. All rights reserved.</copyright></item><item><title>A New Chaos-Based Image-Encryption and Compression Algorithm</title><link>http://www.hindawi.com/journals/jece/2012/179693/</link><description>We propose a new and efficient method to develop secure image-encryption techniques. The new algorithm combines two techniques: encryption and compression. In this technique, a wavelet transform was used to decompose the image and decorrelate its pixels into approximation and detail components. The more important component (the approximation component) is encrypted using a chaos-based encryption algorithm. This algorithm produces a cipher of the test image that has good diffusion and confusion properties. The remaining components (the detail components) are compressed using a wavelet transform. This proposed algorithm was verified to provide a high security level. A complete specification for the new algorithm is provided. Several test images are used to demonstrate the validity of the proposed algorithm. The results of several experiments show that the proposed algorithm for image cryptosystems provides an efficient and secure approach to real-time image encryption and transmission.</description><Author>Somaya Al-Maadeed, Afnan Al-Ali, and Turki Abdalla</Author><copyright>Copyright &amp;#xa9; 2012 Somaya Al-Maadeed et al. All rights reserved.</copyright></item><item><title>Efficient Dual Domain Decoding of Linear Block Codes Using Genetic Algorithms</title><link>http://www.hindawi.com/journals/jece/2012/503834/</link><description>A computationally efficient algorithm for decoding block codes is developed using a genetic algorithm (GA). The proposed algorithm uses the dual code in contrast to the existing genetic decoders in the literature that use the code itself. Hence, this new approach reduces the complexity of decoding the codes of high rates. We simulated our algorithm in various transmission channels. The performance of this algorithm is investigated and compared with competitor decoding algorithms including Maini and Shakeel ones. The results show that the proposed algorithm gives large gains over the Chase-2 decoding algorithm and reach the performance of the OSD-3 for some quadratic residue (QR) codes. Further, we define a new crossover operator that exploits the domain specific information and compare it with uniform and two point crossover. The complexity of this algorithm is also discussed and compared to other algorithms.</description><Author>Ahmed Azouaoui, Mostafa Belkasmi, and Abderrazak Farchane</Author><copyright>Copyright &amp;#xa9; 2012 Ahmed Azouaoui et al. All rights reserved.</copyright></item><item><title>Iterative Signal Processing for Mitigation of Analog-to-Digital Converter Clipping Distortion in Multiband OFDMA Receivers</title><link>http://www.hindawi.com/journals/jece/2012/532560/</link><description>In modern wideband communication receivers, the large input-signal dynamics is a fundamental problem. Unintentional signal clipping occurs, if the receiver front-end with the analog-to-digital interface cannot respond to rapidly varying conditions. This paper discusses digital postprocessing compensation of such unintentional clipping in multiband OFDMA receivers. The proposed method iteratively mitigates the clipping distortion by exploiting the symbol decisions. The performance of the proposed method is illustrated with various computer simulations and also verified by concrete laboratory measurements with commercially available analog-to-digital hardware. It is shown that the clipping compensation algorithm implemented in a turbo decoding OFDM receiver is able to remove almost all the clipping distortion even under significant clipping in fading channel circumstances. That is to say, it is possible to nearly recover the receiver performance to the level, which would be achieved in the equivalent nonclipped situation.</description><Author>Markus All&amp;#233;n, Toni Levanen, Jaakko Marttila, and Mikko Valkama</Author><copyright>Copyright &amp;#xa9; 2012 Markus All&amp;#xe9;n et al. All rights reserved.</copyright></item><item><title>Text-Dependent Writer Identification for Arabic Handwriting</title><link>http://www.hindawi.com/journals/jece/2012/794106/</link><description>This paper proposes a system for text-dependent writer identification based on Arabic handwriting. First, a database of words was assembled and used as a test base. Next, features vectors were extracted from writers' word images. Prior to the feature extraction process, normalization operations were applied to the word or text line under analysis. In this work, we studied the feature extraction and recognition operations of Arabic text on the identification rate of writers. Because there is no well-known database containing Arabic handwritten words for researchers to test, we have built a new database of offline Arabic handwriting text to be used by the writer identification research community. The database of Arabic handwritten words collected from 100 writers is intended to provide training and testing sets for Arabic writer identification research. We evaluated the performance of edge-based directional probability distributions as features, among other characteristics, in Arabic writer identification. Results suggest that longer Arabic words and phrases have higher impact on writer identification.</description><Author>Somaya Al-Maadeed</Author><copyright>Copyright &amp;#xa9; 2012 Somaya Al-Maadeed. All rights reserved.</copyright></item><item><title>Directional Moving Target Indication: A Novel SAR Ambiguity Function for Traffic Monitoring</title><link>http://www.hindawi.com/journals/jece/2012/357034/</link><description>This paper presents and evaluates a novel SAR ambiguity function for traffic monitoring. The novelty consists in introducing the capability to discriminate targets moving in a predefined direction of interest, reducing the contribution of traffic moving in undesired directions. Experimental results show that the modified SAR ambiguity function provides better results than the traditional methodology and may, therefore, be useful for civil traffic monitoring using single-channel synthetic aperture radar data.</description><Author>Paulo Marques</Author><copyright>Copyright &amp;#xa9; 2012 Paulo Marques. All rights reserved.</copyright></item><item><title>Feature Point Extraction from the Local Frequency Map of an Image</title><link>http://www.hindawi.com/journals/jece/2012/182309/</link><description>We propose a novel technique for detecting rotation- and scale-invariant interest points from the local frequency representation of an image. Local or instantaneous frequency is the spatial derivative of the local phase, where the local phase of any signal can be found from its Hilbert transform. Local frequency estimation can detect edge, ridge, corner, and texture information at the same time, and it shows high values at those dominant features of an image. For each pixel, we select an appropriate width of the window for computing the derivative of the phase. In order to select the width of the window for any given pixel, we make use of the measure of the extent to which the phases, in the neighborhood of that pixel, are in the same direction. The local frequency map, thus obtained, is then thresholded by employing a global thresholding approach to detect the interest or feature points. Repeatability rate, a performance evaluation criterion for an interest point detector, is used to check the geometric stability of the proposed method under different transformations. We present simulation results of the detection of feature points from image utilizing the suggested technique and compare the proposed method with five existing approaches that yield good results. The results prove the efficacy of the proposed feature point detection algorithm. Moreover, in terms of repeatability rate; the results show that the performance of the proposed method with respect to different aspect is compatible with the existing methods.</description><Author>Jesmin Khan, Sharif Bhuiyan, and Reza Adhami</Author><copyright>Copyright &amp;#xa9; 2012 Jesmin Khan et al. All rights reserved.</copyright></item><item><title>Discriminant Phase Component for Face Recognition</title><link>http://www.hindawi.com/journals/jece/2012/718915/</link><description>Numerous face recognition techniques have been developed owing to the growing number of real-world applications. Most of current algorithms for face recognition involve considerable amount of computations and hence they cannot be used on devices constrained with limited speed and memory. In this paper, we propose a novel solution for efficient face recognition problem for systems that utilize small memory capacities and demand fast performance. The new technique divides the face images into components and finds the discriminant phases of the Fourier transform of these components automatically using the sequential floating forward search method. A thorough study and comprehensive experiments relating time consumption versus system performance are applied to benchmark face image databases. Finally, the proposed technique is compared with other known methods and evaluated through the recognition rate and the computational time, where we achieve a recognition rate of 98.5&amp;#37; with computational time of 6.4 minutes for a database consisting of 2360 images.</description><Author>Naser Zaeri</Author><copyright>Copyright &amp;#xa9; 2012 Naser Zaeri. All rights reserved.</copyright></item><item><title>Processor Energy Characterization for Compiler-Assisted Software Energy Reduction</title><link>http://www.hindawi.com/journals/jece/2012/786943/</link><description>Energy consumption is a fundamental barrier in
taking full advantage of today and future semiconductor manufacturing
technologies. The paper presents our recent research
activities and results on characterizing and reducing the energy
consumption in embedded systems. Firstly, a technique for
characterizing the energy consumption of embedded processors
during an application execution is presented. The technique
trains a per-processor linear approximation model for fitting
it to the energy consumption of the processor obtained by
postlayout simulation. Secondly, based on the energy model
mentioned above, the paper shows techniques for reducing the
energy consumption by optimally mapping program code, stack
frames, and data items to the scratch-pad memory (SPM) of the
processor memory space.</description><Author>Lovic Gauthier and Tohru Ishihara</Author><copyright>Copyright &amp;#xa9; 2012 Lovic Gauthier and Tohru Ishihara. All rights reserved.</copyright></item><item><title>On Particle Swarm Optimization for MIMO Channel Estimation</title><link>http://www.hindawi.com/journals/jece/2012/614384/</link><description>Evolutionary algorithms, in particular particle swarm optimization (PSO), have recently received much attention. PSO has successfully been applied to a wide range of technical optimization problems, including channel estimation. However, most publications in the area of digital communications ignore improvements developed by the PSO community. In this paper, an overview of the original PSO is given as well as improvements that are generally applicable. An extension of PSO termed cooperative PSO (CPSO) is applied for MIMO channel estimation, providing faster convergence and, thus, lower overall complexity. Instead of determining the average iterations needed empirically, a method to calculate the maximum number of iterations is developed, which enables the evaluation of the complexity for a wide range of parameters. Knowledge of the required number of iterations is essential for a practical receiver design. A detailed discussion about the complexity of the PSO algorithm and a comparison to a conventional minimum mean squared error (MMSE) estimator are given. Furthermore, Monte Carlo simulations are provided to illustrate the MSE performance compared to an MMSE estimator.</description><Author>Christopher Knievel and Peter Adam Hoeher</Author><copyright>Copyright &amp;#xa9; 2012 Christopher Knievel and Peter Adam Hoeher. All rights reserved.</copyright></item><item><title>A Secure Image Encryption Algorithm Based on  Rubik&amp;#39;s Cube Principle</title><link>http://www.hindawi.com/journals/jece/2012/173931/</link><description>In the past few years, several encryption algorithms based on chaotic systems have been proposed
as means to protect digital images against cryptographic attacks. These encryption algorithms typically
use relatively small key spaces and thus offer limited security, especially if they are one-dimensional.
In this paper, we proposed a novel image encryption algorithm based on Rubik&amp;#39;s cube principle. The
original image is scrambled using the principle of Rubik&amp;#39;s cube. Then, XOR operator is applied to rows
and columns of the scrambled image using two secret keys. Finally, the experimental results and security
analysis show that the proposed image encryption scheme not only can achieve good encryption and
perfect hiding ability but also can resist  exhaustive attack, statistical attack, and differential attack.</description><Author>Khaled Loukhaoukha, Jean-Yves Chouinard, and Abdellah Berdai</Author><copyright>Copyright &amp;#xa9; 2012 Khaled Loukhaoukha et al. All rights reserved.</copyright></item><item><title>Computation of Channel Capacity Based on Self-Concordant Functions</title><link>http://www.hindawi.com/journals/jece/2012/318946/</link><description>The computation of channel capacity is a classical issue in information theory. We prove that algorithms based on self-concordant functions can be used to deal with such issues, especially when constrains are included. A new algorithm to compute the channel capacity per unit cost is proposed. The same view is suited to the computation of maximum entropy. All the algorithms are of polynomial time.</description><Author>Da-gang Tian and Yi-qun Huang</Author><copyright>Copyright &amp;#xa9; 2012 Da-gang Tian and Yi-qun Huang. All rights reserved.</copyright></item><item><title>An Efficient Renewable Energy Management and Sharing System for Sustainable Embedded Devices</title><link>http://www.hindawi.com/journals/jece/2012/185959/</link><description>We present the design and evaluation of a capacitor-driven efficient renewable energy management and sharing system, called REMS system, that is designed to replace battery-based energy storage units. We first identify potential applications and requirements of the REMS system.
Then we describe the design of REMS system which aims
at minimizing the energy leaked away and providing accurate
and fine-grained energy sharing between embedded devices.
We extensively evaluate our system under different real-world
settings. Results indicate  that our charging and discharging control
can effectively minimize the energy leaked away. Moreover, the
energy sharing design can efficiently share renewable energy
among multiple devices and significantly extend the lifetime of a
system.</description><Author>Ting Zhu and Chang Zhou</Author><copyright>Copyright &amp;#xa9; 2012 Ting Zhu and Chang Zhou. All rights reserved.</copyright></item><item><title>Impact of CCSDS-IDC and JPEG 2000 Compression on Image Quality and Classification</title><link>http://www.hindawi.com/journals/jece/2012/761067/</link><description>This study measures the impact of both on-board and user-side lossy image compression (CCSDS-IDC and JPEG 2000) on image quality and classification. The Sentinel-2 Image Performance Simulator was modified to include these compression algorithms in order to produce Sentinel-2 simulated images with on-board lossy compression. A multitemporal set of Landsat images was used for the user-side compression scenario in order to study a crop area. The performance of several compressors was evaluated by computing the Signal-to-Noise Ratio (SNR) of the compressed images. The overall accuracy of land-cover classifications of these images was also evaluated. The results show that on-board CCSDS performs better than JPEG 2000 in terms of compression fidelity, especially at lower compression ratios (from CR 2:1 up to CR 4:1, i.e., 8 to 4 bpppb). The effect of compression on land cover classification follows the same trends, but compression fidelity may not be enough to assess the impact of compression on end-user applications. If compression is applied by end-users, the results show that 3D-JPEG 2000 obtains higher compression fidelity than CCSDS and JPEG 2000 with other parameterizations. This is due to the high dynamic range of the images (representing reflectances &amp;#x0002A; 10000), which JPEG 2000 is able to exploit better.</description><Author>Alaitz Zabala, Raffaele Vitulli, and Xavier Pons</Author><copyright>Copyright &amp;#xa9; 2012 Alaitz Zabala et al. All rights reserved.</copyright></item><item><title>Spectral Distortion in Lossy Compression of Hyperspectral Data</title><link>http://www.hindawi.com/journals/jece/2012/850637/</link><description>Distortion allocation varying with wavelength in lossy compression of hyperspectral imagery is investigated, with the aim of minimizing the spectral distortion between original and decompressed data. The absolute angular error, or spectral angle mapper (SAM), is used to quantify spectral distortion, while radiometric distortions are measured by maximum absolute deviation (MAD) for near-lossless methods, for example, differential pulse code modulation (DPCM), or mean-squared error (MSE) for lossy methods, for example, spectral decorrelation followed by JPEG 2000. Two strategies of interband distortion allocation are compared: given a target average bit rate, distortion may be set to be constant with wavelength. Otherwise, it may be allocated proportionally to the noise level of each band, according to the virtually lossless protocol. Comparisons with the uncompressed originals show that the average SAM of radiance spectra is minimized by constant distortion allocation to radiance data. However, variable distortion allocation according to the virtually lossless protocol yields significantly lower SAM in case of reflectance spectra obtained from compressed radiance data, if compared with the constant distortion allocation at the same compression ratio.</description><Author>Bruno Aiazzi, Luciano Alparone, Stefano Baronti, Cinzia Lastri, and Massimo Selva</Author><copyright>Copyright &amp;#xa9; 2012 Bruno Aiazzi et al. All rights reserved.</copyright></item><item><title>Developing a Fuzzy Logic Based on Demand Multicast Routing Protocol</title><link>http://www.hindawi.com/journals/jece/2012/389812/</link><description>Multicast routing is an efficient method to lead data packets from one source group to several nodes as destination group. Although multicast routing algorithms could be efficient in many situations but their routing mechanism like as route request flooding packets likely results in poor performance in comparison to unicast routing algorithms. In this research, two efficient methods are proposed to improve the performance of On Demand Multicast Routing Protocol (ODMRP). The main proposed method tries to establish a small, efficient, and high-quality forwarding group. This is achieved by augmenting the Join Query packets with additional information such as speed, power level of node, and link bandwidths. Besides, the control overhead is further reduced by restricting the domain of control packet flooding (by restricting the domain of control packet flooding). The performance evaluation shows that the proposed scheme increases the packet delivery rate by up to 40&amp;#37;, while reducing average end-to-end delay and consumed power by about 35&amp;#37; and 45&amp;#37;, respectively.</description><Author>Alireza Shams Shafigh, Kamran Abdollahi, and Marjan Kouchaki</Author><copyright>Copyright &amp;#xa9; 2012 Alireza Shams Shafigh et al. All rights reserved.</copyright></item><item><title>An Optimization Mechanism Intended for Static Power Reduction Using Dual-VthTechnique</title><link>http://www.hindawi.com/journals/jece/2012/561580/</link><description>Power consumption reduction is a challenge nowadays. Techniques for dynamic and static power minimization have been proposed, but most of them are very time consuming. This work proposes an algorithm for reducing static power, which can be perfectly inserted in the conventional design flow for integrated systems considering an open source environment (open access infrastructure). The proposed approach, based on a Dual-Threshold technique, replaces part of the cells of the circuit by cells with a higher threshold voltage without resulting in timing violations in the circuit. The decision to replace a cell is based on timing estimates of the circuit modeling with the cell replacement, before it is actually replaced. The fact that only some cells are replaced every iteration results in a reduction of the runtime of the algorithm. Additionally, results showed a reduction in static power up to 39.28&amp;#37;, when applying the proposed approach in the ISCAS85 benchmark circuits.</description><Author>Rodolfo P. Santos, Gabriela S. Clemente, Abel Silva-Filho, Cristiano Ara&amp;#250;jo, Adriano Sarmento, Manoel Lima, and Edna Barros</Author><copyright>Copyright &amp;#xa9; 2012 Rodolfo P. Santos et al. All rights reserved.</copyright></item><item><title>Characterization of Hardware Impairments in Multiple Antenna Systems for DoA Estimation</title><link>http://www.hindawi.com/journals/jece/2011/908234/</link><description>We consider the effects introduced by hardware impairments on the estimation of the direction of arrival (DoA) deploying a multiple antenna radio system. We derive a system model from experimental measurements of a state-of-the-art hardware test bed based on an RF direct-conversion architecture. The system model includes DC offsets, carrier frequency and phase offsets, and the phase noise. Then, we propose a simple digital compensation algorithm of the impairments for bidimensional DoA estimation (azimuth and elevation) with a 3D orthogonal linear array. The robustness of the algorithm in terms of minimum-mean-squared error as a function of the hardware impairments is evaluated and compared with that achieved using the root-MUSIC algorithm.</description><Author>Daniele Inserra and Andrea M. Tonello</Author><copyright>Copyright &amp;#xa9; 2011 Daniele Inserra and Andrea M. Tonello. All rights reserved.</copyright></item><item><title>Differential Difference Current Conveyor Transconductance Amplifier: A New Analog Building Block for Signal Processing</title><link>http://www.hindawi.com/journals/jece/2011/361384/</link><description>A new active building block for analog signal processing, namely, differential difference current conveyor transconductance amplifier (DDCCTA), is presented, and performance is checked through PSPICE simulations which show the usability of the proposed element is up to 201&amp;#x2009;MHz. The proposed block is implemented using 0.25&amp;#x2009;&amp;#x3bc;m TSMC CMOS technology. Some of the applications are presented using the proposed DDCCTA, namely, a voltage mode multifunction filter, a current mode universal filter, an oscillator, current and voltage amplifiers, and grounded inductor simulator. The feasibility of DDCCTA and its applications is confirmed via PSPICE simulations.</description><Author>Neeta Pandey and Sajal K. Paul</Author><copyright>Copyright &amp;#xa9; 2011 Neeta Pandey and Sajal K. Paul. All rights reserved.</copyright></item><item><title>Single CDTA-Based Current Mode All-Pass Filter and Its Applications</title><link>http://www.hindawi.com/journals/jece/2011/897631/</link><description>This paper presents a single current difference transconductance amplifier (CDTA) based all-pass current mode filter. The proposed configuration makes use of a grounded capacitor which makes it suitable for IC implementation. Its input impedance is low and output impedance is high, hence suitable for cascading. The circuit does not use any matching constraint. The nonideality analysis of the circuit is also given. Two applications, namely, a quadrature oscillator and a high Q band pass filter are developed with the proposed circuit. The functionality of the circuit is verified with SPICE simulation using 0.35&amp;#x2009;&amp;#x03BC;m TSMC CMOS technology parameters.</description><Author>Neeta Pandey and Sajal K. Paul</Author><copyright>Copyright &amp;#xa9; 2011 Neeta Pandey and Sajal K. Paul. All rights reserved.</copyright></item><item><title>A Review of Wireless and PLC Propagation Channel Characteristics for Smart Grid Environments</title><link>http://www.hindawi.com/journals/jece/2011/154040/</link><description>Wireless, power line communication (PLC), fiber optic, Ethernet, and so forth are among the communication technologies on which smart grid communication infrastructure is envisioned to be built. Among these, wireless and PLC-based solutions are attractive considering the cost of initial deployment. Wireless communication deployment in smart grid covers a variety of environments such as indoor, outdoor, and electric-power-system facilities. Similar diversity is expected in PLC deployment as well covering low voltage (LV), medium voltage (MV), and high voltage (HV) segments of the grid. In spite of being attractive, wireless and PLC channels are very harsh posing great challenges to performance of communication systems. In proposing solutions to smart grid communication needs, two approaches are likely to be followed. One is based on the use of existing wireless and PLC technologies with some modifications, and the other relies upon developing novel communication protocols particularly addressing the smart grid needs. Both of these approaches require an in-depth knowledge of communication channel characteristics. The aim of this study is to reveal the wireless and PLC channel characteristics of smart grid environments in terms of several parameters such as path loss and attenuation, time dispersion, time selectivity, amplitude statistics, and noise characteristics.</description><Author>Sabih G&amp;#252;zelg&amp;#246;z, H&amp;#252;seyin Arslan, Arif Islam, and Alexander Domijan</Author><copyright>Copyright &amp;#xa9; 2011 Sabih G&amp;#xfc;zelg&amp;#xf6;z et al. All rights reserved.</copyright></item><item><title>A New Efficient Ordering Scheme for Sphere Detection</title><link>http://www.hindawi.com/journals/jece/2011/821407/</link><description>The decoding order has a deep impact in the complexity of sphere detection. A new ordering scheme for sphere detection is presented in this paper, which is based on SIC (serial interference canceling) and the gradient defined by the accumulated probability of the absolute difference between symbol element and the zero-forcing solution. The simulation results show that the proposed ordering scheme can achieve a significant complexity reduction, especially for high numbers of antennas and large constellation sizes in the low SNR region. Compared with sphere detection complexity under BSQR (balanced sorted QR) decomposition and GB (gradient-based) orderings at SNR=5&amp;#x2009;dB, the average number of visited nodes under our proposed ordering is reduced by almost 30&amp;#37; and 33&amp;#37; in 4&amp;#x00D7;4 16QAM system and by almost 30&amp;#37; and 50&amp;#37; reduction in 6&amp;#x00D7;6 16QAM system, respectively. For 4&amp;#x00D7;4 64QAM system, almost 75&amp;#37; and 80&amp;#37; reduction at SNR=0&amp;#x2009;dB and more than 40&amp;#37; and 50&amp;#37; reduction at SNR=5&amp;#x2009;dB can be achieved, respectively.</description><Author>Cao Haiyan and Li Jun</Author><copyright>Copyright &amp;#xa9; 2011 Cao Haiyan and Li Jun. All rights reserved.</copyright></item><item><title>Camera Localization in Distributed Networks Using Trajectory Estimation</title><link>http://www.hindawi.com/journals/jece/2011/604647/</link><description>This paper presents an algorithm for camera localization
using trajectory estimation (CLUTE) in a distributed
network of nonoverlapping cameras. The algorithm recovers the
extrinsic calibration parameters, namely, the relative position and
orientation of the camera network on a common ground plane
coordinate system. We first model the observed trajectories in
each camera&amp;#39;s field of view using Kalman filtering, then we use
this information to estimate the missing trajectory information
in the unobserved areas by fusing the results of a forward and
backward linear regression estimation from adjacent cameras.
These estimated trajectories are then filtered and used to recover
the relative position and orientation of the cameras by analyzing
the estimated and observed exit and entry points of an object in
each camera&amp;#39;s field of view. The final configuration of the network
is established by considering one camera as a reference and by
adjusting the remaining cameras with respect to this reference.
We demonstrate the algorithm on both simulated and real data
and compare the results with state-of-the-art approaches. The
experimental results show that the proposed algorithm is more
robust to noisy and missing data and in case of camera failure.</description><Author>Nadeem Anjum</Author><copyright>Copyright &amp;#xa9; 2011 Nadeem Anjum. All rights reserved.</copyright></item><item><title>A Cache Architecture for Counting Bloom Filters: Theory and Application</title><link>http://www.hindawi.com/journals/jece/2011/475865/</link><description>Within packet processing systems, lengthy memory accesses greatly reduce performance. To overcome this limitation, network processors utilize many different techniques, for example, utilizing multilevel memory hierarchies, special hardware architectures, and hardware threading. In this paper, we introduce a multilevel memory architecture for counting Bloom filters. Based on the probabilities of incrementing of the counters in the counting Bloom filter, a multi-level cache architecture called the cached counting Bloom filter (CCBF) is presented, where each cache level stores the items with the same counters. To test the CCBF architecture, we implement a software packet classifier that utilizes basic tuple space search using a 3-level CCBF. The results of mathematical analysis and implementation of the CCBF for packet classification show that the proposed cache architecture decreases the number of memory accesses when compared to a standard Bloom filter. Based on the mathematical analysis of CCBF, the number of accesses is decreased by at least 53&amp;#x25;. The implementation results of the software packet classifier are at most 7.8&amp;#x25; (3.5&amp;#x25; in average) less than corresponding mathematical analysis results. This difference is due to some parameters in the packet classification application such as number of tuples, distribution of rules through the tuples, and utilized hashing functions.</description><Author>Mahmood Ahmadi and Stephan Wong</Author><copyright>Copyright &amp;#xa9; 2011 Mahmood Ahmadi and Stephan Wong. All rights reserved.</copyright></item><item><title>Unsupervised 3D Prostate Segmentation Based on Diffusion-Weighted Imaging MRI Using Active Contour Models with a Shape Prior</title><link>http://www.hindawi.com/journals/jece/2011/410912/</link><description>Accurate estimation of the prostate location and volume from in vivo images
plays a crucial role in various clinical applications. Recently, magnetic resonance imaging (MRI) is proposed as a promising modality to detect and monitor prostate-related diseases. In this paper, we propose an unsupervised algorithm to segment prostate with 3D apparent diffusion coefficient (ADC) images derived from diffusion-weighted imaging (DWI) MRI without the need of a training dataset, whereas previous methods for this purpose require training datasets. We first apply a coarse segmentation to extract the shape information. Then, the shape prior is incorporated into the active contour model. Finally, morphological operations are applied to refine the segmentation results. We apply our method to an MR dataset obtained from three patients and provide segmentation results obtained by our method and an expert. Our experimental results show that the performance of the proposed method is quite successful.</description><Author>Xin Liu, Masoom A. Haider, and Imam Samil Yetik</Author><copyright>Copyright &amp;#xa9; 2011 Xin Liu et al. All rights reserved.</copyright></item><item><title>New  Low-Power Tristate  Circuits in Positive Feedback  Source-Coupled  Logic</title><link>http://www.hindawi.com/journals/jece/2011/670508/</link><description>Two new design techniques to implement tristate circuits in positive feedback source-coupled logic (PFSCL) have been proposed. The first one is a switch-based technique while the second is based on the concept of sleep transistor. Different tristate circuits based on both  techniques have been developed and simulated using 0.18&amp;#x2009;&amp;#x3bc;m CMOS technology parameters. A performance comparison indicates that the tristate PFSCL circuits based on sleep transistor technique are more power efficient and achieve the lowest power delay product in comparison to CMOS-based and the switch-based PFSCL circuits.</description><Author>Kirti Gupta, Ranjana Sridhar, Jaya Chaudhary, Neeta Pandey, and Maneesha Gupta</Author><copyright>Copyright &amp;#xa9; 2011 Kirti Gupta et al. All rights reserved.</copyright></item><item><title>MO-CCCCTA-Based Floating Positive and Negative Inductors and Their Applications</title><link>http://www.hindawi.com/journals/jece/2011/150354/</link><description>This paper introduces a floating inductance simulation using multiple output current controlled current conveyer transconductance amplifier (MO-CCCCTA). The simulated inductor retains minimum requirement of passive elements as only one-grounded capacitance is used for one inductor. PSPICE simulation has been done and included to ensure the validity of the approach. A few applications have also been included to substantiate the usability of the proposed circuit.</description><Author>Neeta Pandey, Rishik Bazaz, and Rahul Manocha</Author><copyright>Copyright &amp;#xa9; 2011 Neeta Pandey et al. All rights reserved.</copyright></item></channel></rss>
