Journal of Electrical and Computer Engineering The latest articles from Hindawi Publishing Corporation © 2017 , Hindawi Publishing Corporation . All rights reserved. A Comparative Study of Symmetrical Cockcroft-Walton Voltage Multipliers Mon, 16 Jan 2017 00:00:00 +0000 Decades after invention of the Cockcroft-Walton voltage multiplier, it is still being used in broad range of high voltage and ac to dc applications. High voltage ratio, low voltage stress on components, compactness, and high efficiency are its main features. Due to the problems of original circuit, reduction of output ripple and increase of accessible voltage level were the motivations for scientist to propose new topologies. In this article a comparative study on these voltage multipliers was presented. By simulations and experimental prototypes, characteristics of the topologies have been compared. In addition to the performances, components count, voltage stress on the components, and the difficulty and cost of construction are other factors which have been considered in this comparison. An easy to use table which summarized the characteristics of VMs was developed, which can be used as a decision mean for selecting of a topology based on the requirements. It is shown that, due to the application, sometimes a simple and not very famous topology is more effective than a famous one. Mohsen Ruzbehani Copyright © 2017 Mohsen Ruzbehani. All rights reserved. Modified Tang and Pun’s Current Comparator and Its Application to Full Flash and Two-Step Flash Current Mode ADCs Wed, 11 Jan 2017 06:16:55 +0000 A modification to an existing current comparator proposed by Tang and Pun has been presented. The circuit introduces a flipped voltage follower (FVF) which replaces the source follower input stage of the existing current comparator of Tang and Pun. This modification culminates into higher speed especially at lower currents and lower power dissipation. The application of the proposed current comparator has also been put forth by implementing a 3-bit current mode (CM) ADC and a two-step 3-bit CM ADC. The theoretical propositions are verified through spice simulation using 0.18 μm TSMC CMOS technology at a power supply of 1.8 V. Propagation delay, power dissipation, and power delay product (PDP) have been calculated for the proposed current comparator and process parameter variation has been studied. For both the implementations of ADCs, performance parameters, namely, DNL, INL, missing codes, monotonicity, offset, and gain errors, have been evaluated. Veepsa Bhatia and Neeta Pandey Copyright © 2017 Veepsa Bhatia and Neeta Pandey. All rights reserved. A New Digital to Analog Converter Based on Low-Offset Bandgap Reference Mon, 02 Jan 2017 14:08:02 +0000 This paper presents a new 12-bit digital to analog converter (DAC) circuit based on a low-offset bandgap reference (BGR) circuit with two cascade transistor structure and two self-contained feedback low-offset operational amplifiers to reduce the effects of offset operational amplifier voltage effect on the reference voltage, PMOS current-mirror mismatch, and its channel modulation. A Start-Up circuit with self-bias current architecture and multipoint voltage monitoring is employed to keep the BGR circuit working properly. Finally, a dual-resistor ladder DAC-Core circuit is used to generate an accuracy DAC output signal to the buffer operational amplifier. The proposed circuit was fabricated in CSMC 0.5 μm 5 V 1P4M process. The measured differential nonlinearity (DNL) of the output voltages is less than 0.45 LSB and integral nonlinearity (INL) less than 1.5 LSB at room temperature, consuming only 3.5 mW from a 5 V supply voltage. The DNL and INL at −55°C and 125°C are presented as well together with the discussion of possibility of improving the DNL and INL accuracy in future design. Jinpeng Qiu, Tong Liu, Xubin Chen, Yongheng Shang, Jiongjiong Mo, Zhiyu Wang, Hua Chen, Jiarui Liu, Jingjing Lv, and Faxin Yu Copyright © 2017 Jinpeng Qiu et al. All rights reserved. A Novel DBN Feature Fusion Model for Cross-Corpus Speech Emotion Recognition Wed, 28 Dec 2016 07:10:58 +0000 The feature fusion from separate source is the current technical difficulties of cross-corpus speech emotion recognition. The purpose of this paper is to, based on Deep Belief Nets (DBN) in Deep Learning, use the emotional information hiding in speech spectrum diagram (spectrogram) as image features and then implement feature fusion with the traditional emotion features. First, based on the spectrogram analysis by STB/Itti model, the new spectrogram features are extracted from the color, the brightness, and the orientation, respectively; then using two alternative DBN models they fuse the traditional and the spectrogram features, which increase the scale of the feature subset and the characterization ability of emotion. Through the experiment on ABC database and Chinese corpora, the new feature subset compared with traditional speech emotion features, the recognition result on cross-corpus, distinctly advances by 8.8%. The method proposed provides a new idea for feature fusion of emotion recognition. Zou Cairong, Zhang Xinran, Zha Cheng, and Zhao Li Copyright © 2016 Zou Cairong et al. All rights reserved. Hardware Efficient Architecture with Variable Block Size for Motion Estimation Mon, 26 Dec 2016 08:05:52 +0000 Video coding standards such as MPEG-x and H.26x incorporate variable block size motion estimation (VBSME) which is highly time consuming and extremely complex from hardware implementation perspective due to huge computation. In this paper, we have discussed basic aspects of video coding and studied and compared existing architectures for VBSME. Various architectures with different pixel scanning pattern give a variety of performance results for motion vector (MV) generation, showing tradeoff between macroblock processed per second and resource requirement for computation. Aim of this paper is to design VBSME architecture which utilizes optimal resources to minimize chip area and offer adequate frame processing rate for real time implementation. Speed of computation can be improved by accessing 16 pixels of base macroblock of size 4 × 4 in single clock cycle using z scanning pattern. Widely adopted cost function for hardware implementation known as sum of absolute differences (SAD) is used for VBSME architecture with multiplexer based absolute difference calculator and partial summation term reduction (PSTR) based multioperand adders. Device utilization of proposed implementation is only 22k gates and it can process 179 HD (1920 × 1080) resolution frames in best case and 47 HD resolution frames in worst case per second. Due to such higher throughput design is well suitable for real time implementation. Nehal N. Shah, Harikrishna Singapuri, and Upena D. Dalal Copyright © 2016 Nehal N. Shah et al. All rights reserved. Fetal Heart Rate Monitoring from Phonocardiograph Signal Using Repetition Frequency of Heart Sounds Sun, 25 Dec 2016 14:33:57 +0000 As a passive, harmless, and low-cost diagnosis tool, fetal heart rate (FHR) monitoring based on fetal phonocardiography (fPCG) signal is alternative to ultrasonographic cardiotocography. Previous fPCG-based methods commonly relied on the time difference of detected heart sound bursts. However, the performance is unavoidable to degrade due to missed heart sounds in very low signal-to-noise ratio environments. This paper proposes a FHR monitoring method using repetition frequency of heart sounds. The proposed method can track time-varying heart rate without both heart sound burst identification and denoising. The average accuracy rate comparison to benchmark is 88.3% as the SNR ranges from −4.4 dB to −26.7 dB. Hong Tang, Ting Li, Tianshuang Qiu, and Yongwan Park Copyright © 2016 Hong Tang et al. All rights reserved. Design of CPW-Fed Antenna with Defected Substrate for Wideband Applications Tue, 20 Dec 2016 09:28:04 +0000 A CPW-fed defected substrate microstrip antenna is proposed. The proposed antenna shows wideband applications by choosing suitable defected crown shaped substrate. Defected substrate also reduces the size of an antenna. The radiating patch of proposed antenna is taken in the form of extended U-shape. The space around the radiator is utilized by extending the ground plane on both sides of radiator. Simulation of proposed antenna is done on Ansoft’s High Frequency Structure Simulator (HFSS v. 14). Measured results are in good agreement with simulated results. The prototype is taken with dimensions 36 mm × 42 mm × 1.6 mm that achieves good return loss, constant group delay, and good radiation characteristics within the entire operating band from 4.5 to 13.5 GHz (9.0 GHz) with 100% impedance bandwidth at 9.0 GHz centre frequency. Thus, the proposed antenna is applicable for C and X band applications. Amar Sharma, Puneet Khanna, Kshitij Shinghal, and Arun Kumar Copyright © 2016 Amar Sharma et al. All rights reserved. Experiments on Detection of Voiced Hesitations in Russian Spontaneous Speech Sun, 18 Dec 2016 14:34:43 +0000 The development and popularity of voice-user interfaces made spontaneous speech processing an important research field. One of the main focus areas in this field is automatic speech recognition (ASR) that enables the recognition and translation of spoken language into text by computers. However, ASR systems often work less efficiently for spontaneous than for read speech, since the former differs from any other type of speech in many ways. And the presence of speech disfluencies is its prominent characteristic. These phenomena are an important feature in human-human communication and at the same time they are a challenging obstacle for the speech processing tasks. In this paper we address an issue of voiced hesitations (filled pauses and sound lengthenings) detection in Russian spontaneous speech by utilizing different machine learning techniques, from grid search and gradient descent in rule-based approaches to such data-driven ones as ELM and SVM based on the automatically extracted acoustic features. Experimental results on the mixed and quality diverse corpus of spontaneous Russian speech indicate the efficiency of the techniques for the task in question, with SVM outperforming other methods. Vasilisa Verkhodanova and Vladimir Shapranov Copyright © 2016 Vasilisa Verkhodanova and Vladimir Shapranov. All rights reserved. Parameter Extraction of Solar Photovoltaic Modules Using Gravitational Search Algorithm Thu, 15 Dec 2016 14:22:48 +0000 Parameter extraction of a solar photovoltaic system is a nonlinear problem. Many optimization algorithms are implemented for this purpose, which failed in giving better results at low irradiance levels. This article presents a novel method for parameter extraction using gravitational search algorithm. The proposed method evaluates the parameters of different PV panels at various irradiance levels. A critical evaluation and comparison of gravitational search algorithm with other optimization techniques such as genetic algorithm are given. Extensive simulation analyses are carried out on the proposed method and show that GSA is much suitable for parameter extraction problem. R. Sarjila, K. Ravi, J. Belwin Edward, K. Sathish Kumar, and Avagaddi Prasad Copyright © 2016 R. Sarjila et al. All rights reserved. The Comprehensive Study of Electrical Faults in PV Arrays Tue, 06 Dec 2016 13:34:13 +0000 The rapid growth of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency, and safety in PV systems and, if not detected, may not only reduce power generation and accelerated system aging but also threaten the availability of the whole system. Due to the current-limiting nature and nonlinear output characteristics of PV arrays, faults in PV arrays may not be detected. In this paper, all possible faults that happen in the PV system have been classified and six common faults (shading condition, open-circuit fault, degradation fault, line-to-line fault, bypass diode fault, and bridging fault) have been implemented in 7.5 KW PV farm. Based on the simulation results, both normal operational curves and fault curves have been compared. M. Sabbaghpur Arani and M. A. Hejazi Copyright © 2016 M. Sabbaghpur Arani and M. A. Hejazi. All rights reserved. Score-Informed Source Separation for Multichannel Orchestral Recordings Mon, 05 Dec 2016 09:34:13 +0000 This paper proposes a system for score-informed audio source separation for multichannel orchestral recordings. The orchestral music repertoire relies on the existence of scores. Thus, a reliable separation requires a good alignment of the score with the audio of the performance. To that extent, automatic score alignment methods are reliable when allowing a tolerance window around the actual onset and offset. Moreover, several factors increase the difficulty of our task: a high reverberant image, large ensembles having rich polyphony, and a large variety of instruments recorded within a distant-microphone setup. To solve these problems, we design context-specific methods such as the refinement of score-following output in order to obtain a more precise alignment. Moreover, we extend a close-microphone separation framework to deal with the distant-microphone orchestral recordings. Then, we propose the first open evaluation dataset in this musical context, including annotations of the notes played by multiple instruments from an orchestral ensemble. The evaluation aims at analyzing the interactions of important parts of the separation framework on the quality of separation. Results show that we are able to align the original score with the audio of the performance and separate the sources corresponding to the instrument sections. Marius Miron, Julio J. Carabias-Orti, Juan J. Bosch, Emilia Gómez, and Jordi Janer Copyright © 2016 Marius Miron et al. All rights reserved. On the Capacity of MIMO Weibull-Gamma Fading Channels in Low SNR Regime Wed, 30 Nov 2016 13:08:38 +0000 We present capacity analysis for multiple-input multiple-output (MIMO) system under a low signal-to-noise ratio (SNR) regime. We have selected a composite fading channel that considers Weibull fading for multipath and gamma fading for shadowing. We have presented the analysis in a detailed form for three different techniques, namely, spatial multiplexing (SM) with optimal detection, SM with minimum mean square error (MMSE) detection, and orthogonal space-time block codes (OSTBC). Because capacity analysis at arbitrary signal-to-noise (SNR) is stringent, a low SNR regime is considered to achieve a positive rate and wideband slope. The improvement is the result of minimizing energy per information bit . For the first time, closed-form expressions are evaluated for the capacity of MIMO systems at low SNR under WG fading channels which facilitate the performance comparison for proposed techniques. Keerti Tiwari, Davinder S. Saini, and Sunil V. Bhooshan Copyright © 2016 Keerti Tiwari et al. All rights reserved. Contact-Free Cognitive Load Recognition Based on Eye Movement Wed, 30 Nov 2016 11:50:27 +0000 The cognitive overload not only affects the physical and mental diseases, but also affects the work efficiency and safety. Hence, the research of measuring cognitive load has been an important part of cognitive load theory. In this paper, we proposed a method to identify the state of cognitive load by using eye movement data in a noncontact manner. We designed a visual experiment to elicit human’s cognitive load as high and low state in two light intense environments and recorded the eye movement data in this whole process. Twelve salient features of the eye movement were selected by using statistic test. Algorithms for processing some features are proposed for increasing the recognition rate. Finally we used the support vector machine (SVM) to classify high and low cognitive load. The experimental results show that the method can achieve 90.25% accuracy in light controlled condition. Xin Liu, Tong Chen, Guoqiang Xie, and Guangyuan Liu Copyright © 2016 Xin Liu et al. All rights reserved. Audio Watermarking Scheme Based on Singular Spectrum Analysis and Psychoacoustic Model with Self-Synchronization Wed, 30 Nov 2016 06:35:12 +0000 This paper proposes a blind, inaudible, and robust audio watermarking scheme based on singular spectrum analysis (SSA) and the psychoacoustic model 1 (ISO/IEC 11172-3). In this work, SSA is used to analyze the host signals and to extract the singular spectra. A watermark is embedded into the host signals by modifying the singular spectra which are in the convex part of the singular spectrum curve so that this part becomes concave. This modification certainly affects the inaudibility and robustness properties of the watermarking scheme. To satisfy both properties, the modified part of the singular spectrum is determined by a novel parameter selection method based on the psychoacoustic model. The test results showed that the proposed scheme achieves not only inaudibility and robustness but also blindness. In addition, this work showed that the extraction process of a variant of the proposed scheme can extract the watermark without assuming to know the frame positions in advance and without embedding additional synchronization code into the audio content. Jessada Karnjana, Masashi Unoki, Pakinee Aimmanee, and Chai Wutiwiwatchai Copyright © 2016 Jessada Karnjana et al. All rights reserved. A Complete Subspace Analysis of Linear Discriminant Analysis and Its Robust Implementation Wed, 30 Nov 2016 06:32:14 +0000 Linear discriminant analysis has been widely studied in data mining and pattern recognition. However, when performing the eigen-decomposition on the matrix pair (within-class scatter matrix and between-class scatter matrix) in some cases, one can find that there exist some degenerated eigenvalues, thereby resulting in indistinguishability of information from the eigen-subspace corresponding to some degenerated eigenvalue. In order to address this problem, we revisit linear discriminant analysis in this paper and propose a stable and effective algorithm for linear discriminant analysis in terms of an optimization criterion. By discussing the properties of the optimization criterion, we find that the eigenvectors in some eigen-subspaces may be indistinguishable if the degenerated eigenvalue occurs. Inspired from the idea of the maximum margin criterion (MMC), we embed MMC into the eigen-subspace corresponding to the degenerated eigenvalue to exploit discriminability of the eigenvectors in the eigen-subspace. Since the proposed algorithm can deal with the degenerated case of eigenvalues, it not only handles the small-sample-size problem but also enables us to select projection vectors from the null space of the between-class scatter matrix. Extensive experiments on several face images and microarray data sets are conducted to evaluate the proposed algorithm in terms of the classification performance, and experimental results show that our method has smaller standard deviations than other methods in most cases. Zhicheng Lu and Zhizheng Liang Copyright © 2016 Zhicheng Lu and Zhizheng Liang. All rights reserved. A Russian Keyword Spotting System Based on Large Vocabulary Continuous Speech Recognition and Linguistic Knowledge Tue, 29 Nov 2016 13:26:42 +0000 The paper describes the key concepts of a word spotting system for Russian based on large vocabulary continuous speech recognition. Key algorithms and system settings are described, including the pronunciation variation algorithm, and the experimental results on the real-life telecom data are provided. The description of system architecture and the user interface is provided. The system is based on CMU Sphinx open-source speech recognition platform and on the linguistic models and algorithms developed by Speech Drive LLC. The effective combination of baseline statistic methods, real-world training data, and the intensive use of linguistic knowledge led to a quality result applicable to industrial use. Valentin Smirnov, Dmitry Ignatov, Michael Gusev, Mais Farkhadov, Natalia Rumyantseva, and Mukhabbat Farkhadova Copyright © 2016 Valentin Smirnov et al. All rights reserved. An Algorithm of Traffic Perception of DDoS Attacks against SOA Based on Time United Conditional Entropy Sun, 27 Nov 2016 10:28:09 +0000 DDoS attacks can prevent legitimate users from accessing the service by consuming resource of the target nodes, whose availability of network and service is exposed to a significant threat. Therefore, DDoS traffic perception is the premise and foundation of the whole system security. In this paper the method of DDoS traffic perception for SOA network based on time united conditional entropy was proposed. According to many-to-one relationship mapping between the source IP address and destination IP addresses of DDoS attacks, traffic characteristics of services are analyzed based on conditional entropy. The algorithm is provided with perception ability of DDoS attacks on SOA services by introducing time dimension. Simulation results show that the novel method can realize DDoS traffic perception with analyzing abrupt variation of conditional entropy in time dimension. Yuntao Zhao, Hengchi Liu, and Yongxin Feng Copyright © 2016 Yuntao Zhao et al. All rights reserved. First-Order Statistical Characteristics of Macrodiversity System with Three Microdiversity MRC Receivers in the Presence of - Short-Term Fading and Gamma Long-Term Fading Wed, 23 Nov 2016 06:07:39 +0000 Macrodiversity system with macrodiversity SC receiver and three microdiversity MRC (maximum ratio combining) receivers is considered. Independent k-μ short-term fading and correlated Gamma long-term fading are present at the inputs of microdiversity MRC receivers. For this model, the probability density function and the cumulative density function of microdiversity MRC receivers and macrodiversity SC receiver output signal envelopes are calculated. Influences of Gamma shadowing severity, k-μ multipath fading severity, Rician factor and correlation coefficient at probability density function, and cumulative density function of macrodiversity SC receiver output signal envelopes are graphically presented. Branimir Jaksic, Mihajlo Stefanovic, Danijela Aleksic, Dragan Radenkovic, and Sinisa Minic Copyright © 2016 Branimir Jaksic et al. All rights reserved. A Novel Dictionary Learning Model with PT-HLBP for Palmprint Recognition Tue, 22 Nov 2016 13:27:36 +0000 A novel projective dictionary pair learning (PDPL) model with statistical local features for palmprint recognition is proposed. Pooling technique is used to enhance the invariance of hierarchical local binary pattern (PT-HLBP) for palmprint feature extraction. PDPL is employed to learn an analysis dictionary and a synthesis dictionary which are utilized for image discrimination and representation. The proposed algorithm has been tested by the Hong Kong Polytechnic University (PolyU) database (v2) and ideal recognition accuracy can be achieved. Experimental results indicate that the algorithm not only greatly reduces the time complexity in training and testing phase, but also exhibits good robustness for image rotation and corrosion. Xiumei Guo and Weidong Zhou Copyright © 2016 Xiumei Guo and Weidong Zhou. All rights reserved. Speaker Recognition Using Wavelet Cepstral Coefficient, I-Vector, and Cosine Distance Scoring and Its Application for Forensics Sun, 06 Nov 2016 08:59:11 +0000 An important application of speaker recognition is forensics. However, the accuracy of speaker recognition in forensic cases often drops off rapidly because of the ill effect of ambient noise, variable channel, different duration of speech data, and so on. Therefore, finding a robust speaker recognition model is very important for forensics. This paper builds a new speaker recognition model based on wavelet cepstral coefficient (WCC), i-vector, and cosine distance scoring (CDS). This model firstly uses the WCC to transform the speech into spectral feature vecors and then uses those spectral feature vectors to train the i-vectors that represent the speeches having different durations. CDS is used to compare the i-vectors to give out the evidence. Moreover, linear discriminant analysis (LDA) and the within-class covariance normalization (WCNN) are added to the CDS algorithm to deal with the channel variability problem. Finally, the likelihood ratio estimates the strength of the evidence. We use the TIMIT database to evaluate the performance of the proposed model. The experimental results show that the proposed model can effectively solve the troubles of forensic scenario, but the time cost of the method is high. Lei Lei and She Kun Copyright © 2016 Lei Lei and She Kun. All rights reserved. Modelling and Automated Implementation of Optimal Power Saving Strategies in Coarse-Grained Reconfigurable Architectures Wed, 02 Nov 2016 11:10:57 +0000 This paper focuses on how to efficiently reduce power consumption in coarse-grained reconfigurable designs, to allow their effective adoption in heterogeneous architectures supporting and accelerating complex and highly variable multifunctional applications. We propose a design flow for this kind of architectures that, besides their automatic customization, is also capable of determining their optimal power management support. Power and clock gating implementation costs are estimated in advance, before their physical implementation, on the basis of the functional, technological, and architectural parameters of the baseline design. Experimental results, on 90 and 45 nm CMOS technologies, demonstrate that the proposed approach guides the designer towards optimal implementation. Francesca Palumbo, Tiziana Fanni, Carlo Sau, Paolo Meloni, and Luigi Raffo Copyright © 2016 Francesca Palumbo et al. All rights reserved. A Model for Analyzing a Five-Phase Fractional-Slot Permanent Magnet Tubular Linear Motor with Modified Winding Function Approach Thu, 27 Oct 2016 08:32:05 +0000 This paper presents a model for analyzing a five-phase fractional-slot permanent magnet tubular linear motor (FSPMTLM) with the modified winding function approach (MWFA). MWFA is a fast modeling method and it gives deep insight into the calculations of the following parameters: air-gap magnetic field, inductances, flux linkages, and detent force, which are essential in modeling the motor. First, using a magnetic circuit model, the air-gap magnetic density is computed from stator magnetomotive force (MMF), flux barrier, and mover geometry. Second, the inductances, flux linkages, and detent force are analytically calculated using modified winding function and the air-gap magnetic density. Finally, a model has been established with the five-phase Park transformation and simulated. The calculations of detent force reveal that the end-effect force is the main component of the detent force. This is also proven by finite element analysis on the motor. The accuracy of the model is validated by comparing with the results obtained using semianalytical method (SAM) and measurements to analyze the motor’s transient characteristics. In addition, the proposed method requires less computation time. Bo Zhang, Rong Qi, Hui Lin, and Julius Mwaniki Copyright © 2016 Bo Zhang et al. All rights reserved. Improving Robustness of Biometric Identity Determination with Digital Watermarking Thu, 27 Oct 2016 08:07:41 +0000 The determination of an identity from noisy biometric measurements is a continuing challenge. In many applications, such as identity-based encryption, the identity needs to be known with virtually 100% certainty. The determination of identities with such precision from face images taken under a wide range of natural situations is still an unsolved problem. We propose a digital watermarking based method to aid face recognizers to tackle this problem in applications. In particular, we suggest embedding multiple face dependent watermarks into an image to serve as expert knowledge on the corresponding identities to identity-based schemes. This knowledge could originate, for example, from the tagging of those people on a social network. In our proposal, a single payload consists of a correction vector that can be added to the extracted biometric template to compile a nearly noiseless identity. It also supports the removal of a person from the image. If a particular face is censored, the corresponding identity is also removed. Based on our experiments, our method is robust against JPEG compression, image filtering, and occlusion and enables a reliable determination of an identity without side information. Juha Partala, Angelos Fylakis, Anu Pramila, Anja Keskinarkaus, and Tapio Seppänen Copyright © 2016 Juha Partala et al. All rights reserved. Assessing Availability in Wireless Visual Sensor Networks Based on Targets’ Perimeters Coverage Wed, 26 Oct 2016 08:47:49 +0000 Availability in wireless visual sensor networks is a major design issue that is directly related to applications monitoring quality. For targets monitoring, visual sensors may be deployed to cover most or all of targets, and monitoring quality may be focused on how well a set of targets are being covered. However, targets may have different dimensions and it is expected that large targets may be only partially viewed by source nodes, which may affect coverage quality and lead to a state of unavailability. In this context, this article analyzes the effect of target’s size on effective coverage in wireless visual sensor networks. A new coverage metric, the Effective Target Viewing (ETV), is proposed to measure monitoring quality over a set of targets, which is exploited as a fundamental parameter for availability assessment. Results show that ETV can be used as a practical coverage metric when assessing availability in wireless visual sensor networks. Daniel G. Costa and Cristian Duran-Faundez Copyright © 2016 Daniel G. Costa and Cristian Duran-Faundez. All rights reserved. Intermediate Frequency Digital Receiver Based on Multi-FPGA System Tue, 25 Oct 2016 13:39:12 +0000 Aiming at high-cost, large-size, and inflexibility problems of traditional analog intermediate frequency receiver in the aerospace telemetry, tracking, and command (TTC) system, we have proposed a new intermediate frequency (IF) digital receiver based on Multi-FPGA system in this paper. Digital beam forming (DBF) is realized by coordinated rotation digital computer (CORDIC) algorithm. An experimental prototype has been developed on a compact Multi-FPGA system with three FPGAs to receive 16 channels of IF digital signals. Our experimental results show that our proposed scheme is able to provide a great convenience for the design of IF digital receiver, which offers a valuable reference for real-time, low power, high density, and small size receiver design. Chengchang Zhang and Lihong Zhang Copyright © 2016 Chengchang Zhang and Lihong Zhang. All rights reserved. A Searching Method of Candidate Segmentation Point in SPRINT Classification Mon, 24 Oct 2016 12:25:53 +0000 SPRINT algorithm is a classical algorithm for building a decision tree that is a widely used method of data classification. However, the SPRINT algorithm has high computational cost in the calculation of attribute segmentation. In this paper, an improved SPRINT algorithm is proposed, which searches better candidate segmentation point for the discrete and continuous attributes. The experiment results demonstrate that the proposed algorithm can reduce the computation cost and improve the efficiency of the algorithm by improving the segmentation of continuous attributes and discrete attributes. Zhihao Wang, Junfang Wang, Yonghua Huo, Yanjun Tuo, and Yang Yang Copyright © 2016 Zhihao Wang et al. All rights reserved. Joint Radio Resource Allocation and Base Station Location Selection in OFDMA Based Private Wireless Access Networks for Smart Grid Sun, 23 Oct 2016 12:33:24 +0000 This paper studies the base stations deployment problem in orthogonal frequency-division multiple access (OFDMA) based private wireless access networks for smart grid (SG). Firstly, we analyze the differences between private wireless access networks for SG and public cellular access networks. Then, we propose scheduling and power control based algorithms for the radio resource allocation subproblem and K-means, simulated annealing (SA), and particle swarm optimization (PSO) based algorithms for the base station (BS) location selection subproblem and iterate over these two sets of algorithms to solve the target problem. Simulation results show that the proposed method can effectively solve the target problem. Specifically, the combination of power control based resource allocation algorithm and PSO based location selection algorithm is recommended. Peng Du and Yuan Zhang Copyright © 2016 Peng Du and Yuan Zhang. All rights reserved. A Novel Framework for Interactive Visualization and Analysis of Hyperspectral Image Data Thu, 13 Oct 2016 11:55:41 +0000 Multispectral and hyperspectral images are well established in various fields of application like remote sensing, astronomy, and microscopic spectroscopy. In recent years, the availability of new sensor designs, more powerful processors, and high-capacity storage further opened this imaging modality to a wider array of applications like medical diagnosis, agriculture, and cultural heritage. This necessitates new tools that allow general analysis of the image data and are intuitive to users who are new to hyperspectral imaging. We introduce a novel framework that bundles new interactive visualization techniques with powerful algorithms and is accessible through an efficient and intuitive graphical user interface. We visualize the spectral distribution of an image via parallel coordinates with a strong link to traditional visualization techniques, enabling new paradigms in hyperspectral image analysis that focus on interactive raw data exploration. We combine novel methods for supervised segmentation, global clustering, and nonlinear false-color coding to assist in the visual inspection. Our framework coined Gerbil is open source and highly modular, building on established methods and being easily extensible for application-specific needs. It satisfies the need for a general, consistent software framework that tightly integrates analysis algorithms with an intuitive, modern interface to the raw image data and algorithmic results. Gerbil finds its worldwide use in academia and industry alike with several thousand downloads originating from 45 countries. Johannes Jordan, Elli Angelopoulou, and Andreas Maier Copyright © 2016 Johannes Jordan et al. All rights reserved. Cross-Layer Control with Worst Case Delay Guarantees in Multihop Wireless Networks Mon, 10 Oct 2016 12:15:25 +0000 The delay guarantee is a challenge to meet different real-time requirements in applications of backpressure-based wireless multihop networks, and therefore, researchers are interested in the possibility of providing bounded end-to-end delay. In this paper, a new cross-layer control algorithm with worst case delay guarantees is proposed. The utility maximization algorithm is developed using a Lyapunov optimization framework. Virtual queues that ensure the worst case delay of nondropped packets are designed. It is proved through rigorous theoretical analyses and verified by simulations that the time average overall utility achieved by the new algorithm can be arbitrarily close to the optimal solution with finite queue backlogs. The simulation results evaluated with Matlab show that the proposed algorithm achieves higher throughput utility with fewer data dropped compared with the existing work. Shu Fan and Honglin Zhao Copyright © 2016 Shu Fan and Honglin Zhao. All rights reserved. A Novel Method for Constructing Grid Multi-Wing Butterfly Chaotic Attractors via Nonlinear Coupling Control Wed, 05 Oct 2016 12:34:41 +0000 A new method is presented to construct grid multi-wing butterfly chaotic attractors. Based on the three-dimensional Lorenz system, two first-order differential equations are added along with one linear coupling controller, respectively. And a piecewise linear function, which is taken into the linear coupling controller, is designed to form a nonlinear coupling controller; thus a five-dimensional chaotic system is produced, which is able to generate gird multi-wing butterfly chaotic attractors. Through the analysis of the equilibrium points, Lyapunov exponent spectrums, bifurcation diagrams, and Poincaré mapping in this system, the chaotic characteristic of the system is verified. Apart from the research above, an electronic circuit is designed to implement the system. The circuit experimental results are in accordance with the results of numerical simulation, which verify the availability and feasibility of this method. Yun Huang Copyright © 2016 Yun Huang. All rights reserved.