2009 Vol. 18, No. 3

Display Method:
Grid Scheduling Based on Prediction of Task Completion Time
WU Yongwei, CHEN Gang, YANG Guangwen, ZHENG Weimin
2009, 18(3): 389-394.
Abstract(455) PDF(708)
Scheduling problems of grid research area are paid moreand more attention recently. In this paper, a grid Scheduling modelbased on prediction of task completion time (SPCT) is proposed. ThroughUsing Least Squares Discrete Curve Fitting, SPCT dynamicallyestablishes the regression function of Completion time of task (CTT)according to the historical record first. Predicted completion time ofeach coming task is calculated for each candidate node with theregression function secondly. And then, the node with the least valuewill be allocated to run the task. The SPCT is used to input datasensitive applications and implemented in one real-world gridenvironment, Bioinformatics Grid Platform. Experimental result showsthat the SPCT could reduce the average CTT of tasks by 19%.
Path Planning for Mobile Robot Based on an Improved Probabilistic Roadmap Method
LIU Changan, CHANG Jingang, LIU Chunyang
2009, 18(3): 395-399.
Abstract(453) PDF(1282)
Probabilistic roadmap method planners have been work in path planning ofmobile robots, but sampling narrow passages in robot configuration spaceremains a challenge for PRM planning. This paper presents an improvedprobabilistic roadmap method for finding paths through narrow passages.A key ingredient of the new method is Branching random walk, which ismore integrated into probabilistic roadmap to capture the connectivityof free spaces with difficult narrow passages. The paper implementedthe planner and tested it on articulated robots in 2-D environments.Simulation shows that the method enables relatively small roadmaps toreliably capture the connectivity of configuration spaces withdifficult narrow passages. The method adopts to search path by use ofmore integrated of probabilistic roadmap, decreases time of collisiondetection, gets local optimal path, and improves the efficiency ofalgorithm.
Unbounded Non-Malleable Non-Interactive Zero Knowledge Protocols for NP
HUANG Guifang, LIN Dongdai
2009, 18(3): 400-404.
Abstract(451) PDF(594)
In asynchronous network communication, non-malleability is requiredto resist against man-in-the-middle attack. Based on the existenceof one-way permutation, we propose two unbounded non-malleableNon-interactive zero knowledge (NIZK) protocols. Firstly, by usingNIZK argument of knowledge instead of as abuilding block, we transform 5-rounds concurrent non-malleable zeroknowledge argument in the Common reference string (CRS)model[15] to non-malleable NIZK argument. The transformationachieves optimal round efficiency in the same model. Secondly, wesimplify the second scheme in CRYPO'01[8] by using thetechnique hidden unduplicatable set selection. In thesimplified scheme, the CRS is much shorter and statements to beproved in the two NIZK sub-protocols are simplified.
KernelRank: Exploiting Semantic Linkage Kernelsfor Relevant Pages Finding
WANG Yaowei, SU Limin, TIAN Yonghong
2009, 18(3): 405-410.
Abstract(410) PDF(498)
Relevant pages finding is to find a set of relevantpages that address the same topic as the given page. Hyperlinkrelationship is an important useful clue for this task. Some hyperlinksare useful, also some are irrelevant or noisy. Therefore, it isimportant to design efficient relevant pages finding methods that canwork well in the real-world Web data. In this paper, we propose arelevant pages finding algorithm, KernelRank. This algorithm takesadvantage of linkage kernels to reveal latent semantic relationshipsamong pages and to identify relevant pages precisely and effectively.Experiments are conducted on WT10G and the results show that theKernelRank algorithm is feasible and effective.
Secure Network Coding Against the Contamination and Eavesdropping Adversaries
ZHOU Yejun, LI Hui, MA Jianfeng
2009, 18(3): 411-416.
Abstract(442) PDF(1555)
An algorithm that targets contamination andeavesdropping adversaries is presented. By means of our algorithm,every node can verify the integrity of the received packets easily andan eavesdropper is unable to get any "meaningful information" about thesource. We call it "practical security" if an eavesdropper is unable toget any meaningful information about the source. We show that, bygiving up a small amount of overall capacity, our algorithm achievesthe practically secure condition at a probability of one. Furthermore,the communication overhead of our algorithm is negligible compared withprevious works, since the transmission of the hash values and the codecoefficients are both avoided.
Dynamical Trust Construction Schema with Fuzzy Decision in P2P Systems
WANG Yang, WANG Ruchuan, HAN Zhijie
2009, 18(3): 417-421.
Abstract(457) PDF(713)
The security problem for Peer-to-peer (P2P) systems hasbeen gradually recognized as an important topic of P2P applications.Among existing solution for P2P security, how to establish trustrelationship among peers is a key problem in demand. This paperproposes a novel dynamical trust construction schema based on fuzzydecision and Extended automated trust negotiation (EATN). The presentedapproach adopts fuzzy trust graph to describe the trust information inthe P2P systems. Trust relationship among peers can be constructed bythe combination of the fuzzy trust graph, fuzzy path search algorithmand EATN. The relevant application case indicates the schema isfeasible. The simulations also show that the presented schema canimprove the interactive success ratio by enhancing the trustrelationship in the P2P systems.
Quantum Bit Commitment Based on Qubit Oblivious Transfer
YANG Wei, HUANG Liusheng, WANG Qiyan, LUO Yonglong
2009, 18(3): 422-426.
Abstract(421) PDF(1190)
Bit commitment (BC) is a powerful primitive of greattheoretical and practical significance. In order to resist coherentattack of BC scheme, we decrease Alice's participation responsibilityin the protocol to avoid any chance that she solely prepares particlesfor Bob. We introduce an extended version of 1-out-of-2 oblivioustransfer 1-out-of-2 qubit oblivious transfer (1-out-of-2 qu-OT), andshow that 1-out-of-2 qu-OT is sufficient to lead to quantum BC. In ournew BC scheme, Alice and Bob jointly prepare a four-particle systembefore the protocol under the surveillance of each other, whichexcludes any participant's misbehaviors during the preparation phaseand thus the presented BC scheme does not break Mayers-Lo-Chau no-gotheorem.
A Spectrum Based Algorithm for Image Classification
WANG Nian, ZHANG Jiang, TANG Jun, FAN Yizheng, LIANG Dong
2009, 18(3): 427-430.
Abstract(439) PDF(510)
In this paper, a novel algorithm for imageclassification is presented which uses the projective value ofadjacency spectrum as classified samples. Firstly, the eigenvalues ofadjacency matrices constructed on the feature point-sets of images areobtained by singular value decomposition. Secondly, the eigenvalues areprojected onto the eigenspace by means of the covariance matrix.Finally, image classification is performed by adopting RBF and PNNneural networks as classifiers respectively. Meanwhile, sometheoretical analyses are given to support the proposed method.
Illumination Estimation Based on Color Invariant
LI Bing, XU De, FENG Songhe
2009, 18(3): 431-434.
Abstract(420) PDF(846)
Illumination estimation is most important step in colorconstancy computation. Although a number of elaborate algorithms wereproposed, methods like grey world and Max are still widely usedbecause of their low computational costs. The grey world algorithm isbased on the grey world assumption: the average reflectance in a sceneis achromatic. But this assumption can not be always satisfied well.Borrowing on some of the strengths and simplicity of the grey worldalgorithm, we propose a novel algorithm called Illumination estimationbased on color invariant (IECI) to improve the performance of greyworld, in which the achromatic surfaces are identified for illuminationestimation. As we know, the color of achromatic surface can completelyreflect the illumination color incident on the scene. In light of thisidea, color invariant technique is introduced to approximately identifythe achromatic surfaces, then iterative method is used to improveaccuracy of the proposed method. The experimental results show that theproposed algorithm can get satisfying results and outperforms somecurrent state-of-the-art color constancy algorithms.
The Study of a Micro Channel Integrated Gas Flow Sensor
YU Bolin, GAN Zhiyin, XU Jingping, LIU Sheng
2009, 18(3): 435-438.
Abstract(445) PDF(1182)
In this paper, a micro channel with integrated gas mass flowsensor is proposed for high sensitivity. The uniqueness of this flowsensor is that there is thermal convection effect on two sides ofdiaphragm, which results in a more sensitive temperature distribution.Flow and temperature characteristics of the novel flow sensor aresimulated at different flow rates. The most sensitive position isobtained, and optimum is 120m--200m when the flow velocityvaries from 0m/s to 5m/s. Compared with traditional flow sensors, this flowsensor has higher measurement precision. The micro channel integratedgas mass flow sensor is fabricated by semiconductor technology, and theimprovement of output signal by flow guide is obvious. When theincoming flow is 5m/s, the output signal can reaches about 4.2V and 3Vfor the flow sensing with and without flow guide.
An Area and Power Efficient Near-Lossless Image Compressor for Medical Application
CHEN Xinkai, ZHANG Xiaoyu, LI Xiaowen, JIANG Hanjun, ZHANG Chun, WANG Zhihua
2009, 18(3): 439-443.
Abstract(436) PDF(689)
An innovative design is presented whichimplements an area and power efficient near-lossless image compressorin an ASIC for power-constrained image sensor nodes in medical fieldsuch as the wireless endoscope capsule. The compressor is composed of aJPEG-LS encoder with a novel hardware-oriented image filter whichimproves the average compression by 17.3%. Architecture designtechniques such as parallel pipelines and in-stage resource sharing areextremely employed to save the die area. Low power design techniquessuch as hierarchy memory access, clock gating and voltage scaling areused to reduce power consumption. The compressor occupies a die area of0.85mm2 in 0.18m 1P6M CMOS technology. The implementedJPEG-LS encoder costs the lowest gate counts and memory requirement inthe reported literature. For VGA images at 15 frames per second, thereal-time compression can be achieved at 20MHz clock frequency withpower dissipation of 800uW at 1.1V supply voltage.
Real-Time Coding Scheme for High-Resolution Remote Sensing Images
DENG Chenwei, ZHAO Baojun
2009, 18(3): 444-448.
Abstract(438) PDF(524)
Traditional wavelet-based bit-plane coding schemesare not suitable for hardware pipeline processing. To address thisissue, a fast hybrid coding framework is proposed based upon theproperties of high-resolution images. Wavelet coefficients arepartitioned into three types: the low-pass subband is encodedlosslessly; the first level high-pass subbands undergo run-lengthcoding on the basis of wide quantization; the other subbands areprocessed with adaptive quantization. According to the relationshipbetween input and output data ratio, quantization threshold can beadjusted dynamically, and variable compression ratio can be achieved.Experimental results show that, the proposed algorithm provides similarvisual quality and PSNR results in comparison with other typicalschemes, however, the execution time is less than one-fifth of such ones.
Graph-Cuts Fusion of Distance Fidelity Mapsfor Volumetric Multi-view Stereo
LIU Yebin, DAI Qionghai, XU Wenli
2009, 18(3): 449-454.
Abstract(439) PDF(494)
This paper presents a new graph-cuts based volumetricreconstruction technique for multi-view stereo. To refrain from theballoon constraint term widely used in 3D reconstruction approaches, wepropose the using of a more sophisticated and high performance map,namely the distance fidelity map, for graph-cuts optimization. Theapproach first seeks to compute the optimal Distance fidelity map (DFM)of each view using photo-consistency, feature constraint, silhouetteconstraint and smoothness constraint. Occlusion robust and featurerobust mechanism are also considered during this process. After this,according to our proposed objective function, multiple DFMs are fusedinto a graph-cuts framework to give a watertight surface that bestcapture the surface detail. Results demonstrate the high performancereconstruction quality using only 10 views and its generality toextensive actor structures.
Universal Methodology for Developing Quantitative Steganalysis
GUO Yanqing, KONG Xiangwei, YOU Xingang, LI Lingling
2009, 18(3): 455-459.
Abstract(452) PDF(687)
The objective of quantitative steganalysis is to achievereliable estimation of embedded message length of a suspected digitalobject. This type of methods has received considerable attention due toits capability of providing more detailed information about embeddedsecrets rather than just determining whether a suspected object isstego or not. In this paper, we present the methodology of "universalquantitative steganalysis", which is a practical, unified approach fordesigning quantitative steganalytic methods based on statisticallearning techniques. This methodology models the relation betweenembedded message length and statistical feature change caused by theembedding process with a multivariable function, and solves the problemof optimal parameter estimation with SVR (Support vector regression)technique. Experimental results indicate that new quantitativesteganalytic methods applying the presented methodology can achieveexcellent performance for F5 and MB1 steganographic mechanisms.
Trace Representations of Generalized Cyclotomic Sequences of Length p q with Arbitrary Order
DU Xiaoni, CHEN Zhixiong
2009, 18(3): 460-464.
Abstract(429) PDF(495)
The constructions of two main classes of generalized cyclotomic binarysequences of length pq with arbitrary order are presentedby using generalized cyclotomic classes in the sense of Whiteman and ofDing-Helleseth. The trace representations of the correspondingsequences are determined by computing their defining pairs. As anapplication, the trace representations are used to determine the linearcomplexity by using the Key's method.
Weight Distributions of Two Classes of Linear Codes from Perfect Nonlinear Functions
DAI Qingping, LI Chao
2009, 18(3): 465-470.
Abstract(448) PDF(557)
The weight distributions of two classes of linear codes from all knownperfect nonlinear functions from F_p^m to itself are determined,based on the Pless power moments. These results suggest that two openproblems proposed by C. Carlet, C. Ding and J. Yuan in 2005 are solvedby a new kind of uniform approach.
Joint Approximate Diagonalization Using Bilateral Rank-Reducing Householder Transform with Application in Blind Source Separation
ZHANG Weitao, LIU Ning, LOU Shuntian
2009, 18(3): 471-476.
Abstract(425) PDF(1436)
This paper addresses the problem of Jointapproximate diagonalization (JAD) of a set of given matrices andproposes a new efficient iterative algorithm for JAD that based on therank-reducing structure of Householder transform. The proposedalgorithm, named as HJD, completes the simultaneous diagonalization ofthe target matrices by successive Householder transform from the pointof view of matrix power concentration. Generally, the power of theelements below diagonal element was concentrated to the diagonalelement by the rank-reducing Householder transform. Such a particularstructure of Householder transform at each iteration prevents thedivergence of matrix power. The diagonalization matrix was calculatedby the product of all Householder matrices. By applying our algorithmto blind source separation, we demonstrate the efficiency andimprovement of the proposed algorithm in estimating the separationmatrix.
Design of M-Channel Uniform Linear-Phase Filter Banks with Partial Cosine Modulation
ZHONG Wei, SHI Guangming, XIE Xuemei, CHEN Xuyang
2009, 18(3): 477-480.
Abstract(401) PDF(605)
In this paper, a method of partial cosine modulation isproposed to maintain the Linear-phase (LP) property of M-channeluniform filter banks. We design the lowpass analysis filter separately,getting the highpass by shifting it by pi, and obtain the bandpass viacosine modulation of a prototype filter, justifying the name "partialcosine modulation". For the elimination of significant aliasingdistortion, a necessary and sufficient condition is derived. With theproposed design criteria, the problem of uniform LP bank design becomesthat of designing only two filters, one prototype and the lowpassfilter, leading to a less design effort. By employing theParks-McClellan algorithm, a global optimum solution in the minimaxsense can be obtained. In addition, the proposed method is applicableto filter banks with arbitrary number of channels and offers moreflexible in choosing the filter length.
Speech Enhancement Using Compact Microphone Array and Applications in Distant Speech Acquisition
ZHANG Heng, FU Qiang, YAN Yonghong
2009, 18(3): 481-486.
Abstract(468) PDF(718)
In this paper, a novel two-element-microphone-array-based speechenhancement algorithm is proposed. This algorithm is designed toachieve better overall performance with relatively small array size. Afrequency domain adaptive null-forming is used, in which adaptive noisecancelation is implemented in auditory subbands. And an OM-LSA basedpostfiltering stage further purifies the output. The algorithm alsofeatures interaction between the array processing and the postfilter tomake the filter adaptation more robust. This approach achievesconsiderable improvement on Signal-to-noise ratio (SNR) and subjectivequality of the desired speech. Experiments confirm the effectiveness ofthe proposed system.
Exposing Copy-Paste-Blur Forgeries Based on Color Coherence
WANG Bo, KONG Xiangwei, Elisa Bertino, FU Haiyan
2009, 18(3): 487-49.
Abstract(455) PDF(1125)
Exposing digital image forgeries is a major challengefor photography authentication and forensics investigation, which aimsat proving the authenticity of digital photos. In this paper, weintroduce a digital image forensics approach based on color coherenceto exposing copy-paste-blur forgeries. We first discuss the inherentcolor coherence introduced by imaging pipeline, and then obtain severalstatistical features from the coherence characterization. Using the SVMclassifier, we reveal traces of copy-paste-blur tampering inphotographic forgeries. Experimental results indicate that the proposedmethod can effectively expose the copy-paste-blur forgeries andlocalize the tampered regions with high accuracy.
A Cancer Recognition Method Based on DNA Microarray
SU Qian, AN Dong, ZHAI Yafeng, WANG Ku, WANG Shoujue
2009, 18(3): 491-493.
Abstract(662) PDF(524)
The accurate cancer classification is of great importance inclinical treatment. Recently, the DNA microarray technology provides apromising approach to the diagnosis and prognosis of cancer types.However, it has no perfect method for the multiclass classificationproblem. The difficulty lies in the fact that the data are of highdimensionality with small sample size. This paper proposed an automaticclassification method of multiclass cancers based on Biomimetic patternrecognition (BPR). To the public GCM data set, the average correctclassification rate reaches 80% under the condition that the correctrejection rate is 81%.
Leveled Group Key Management with Efficient Revocations for Wireless Sensor Networks
LI Fenghua, YAN Junzhi, MA Jianfeng, WANG Wei
2009, 18(3): 494-499.
Abstract(440) PDF(1273)
Wireless sensor networks are often deployed in hostileenvironments. Protecting the communication against node capture is oneof the most important design objectives. Focused on the revocations ofresource constrained nodes, an efficient leveled group key managementscheme is proposed. This scheme is based on a novel application of ana-ary logical key tree. Since sensor nodes may leaveor join the WSN frequently, a sublevel session key is introduced toprotect the sensitive information transmitted in the network. In aleave event, the remaining legal sensors in the key tree arepartitioned into disjointed subtrees. The group key can be updatedsecurely by encrypting the new group key with the common keys shared bythe sensors in the same subtree. When a sensor requests to join thecommunication group, it is assigned a sublevel session key which isused to communicate with GCKS and other legal sensors. The currentsession key is sent to the new sensor only after it gets the trust ofGCKS. This scheme is scalable, stateless and simple to employ.
MMSE Turbo Equalizer with Preprocessor
2009, 18(3): 500-503.
Abstract(403) PDF(643)
A modified linear Minimum mean squared error (MMSE) turboequalizer is proposed in this paper. The proposed method introduces amatched filter, which is used to preprocess the received symbolsequence, into the MMSE turbo equalizer. This matched filter canconcentrate the received symbol sequence and, consequently, shorten thelength of the observation vector without any information loss. Thecomplexity of the MMSE turbo equalizer can be reduced, owing to itscubicity in the length of the observation vector. The simulation resultconfirms that our modified MMSE turbo equalizer performs as well as theoriginal MMSE turbo equalizer with much lower complexity. Moreover, themodified algorithm can provide more flexibility in choosing the lengthof the observation vector, and therefore is more suitable for themulti-path channel with large delay spread.
Probabilistic Analysis Methods of S-Boxes and Their Applications
LIU Fuyun, DONG Qingkuan, XIAO Guozhen
2009, 18(3): 504-508.
Abstract(426) PDF(807)
The relations between cryptographic properties of S-boxand its component functions are researched in this paper. First, theconcepts of independence and probability product function ofS-box are introduced, the inversion formula and its fast transformationof output probability between an S-box and the linear combination of itscomponent functions are presented, which are very useful tools inanalyzing cryptographic properties of S-boxes. Then, the necessary andsufficient conditions of S-boxes with balancedness or correlationimmunity are investigated. Finally, the necessary and sufficientconditions of independence of S-boxes are given and proved.
An Improved Bayesian-based RFID Indoor Location Algorithm
HUANG Yihua, LUI Zongyuan, LING Guojun, LV Shilei
2009, 18(3): 509-512.
Abstract(447) PDF(816)
RFID technologies attract more attention forits good performance in many applications. Indoor location based onactive RFID technologies provides an approach with a high performanceto price ratio, which further expands the applications. This paperproposes a new algorithm, which is based on analysis of LANDMARCalgorithm and the general Bayesian-based algorithm. Our algorithm isessentially a Bayesian-based algorithm, but it makes some improvementsto overcome the drawbacks of LANDMARC algorithm and the generalBayesian-based algorithm. Simulation results show that our algorithmcan provide better performance than LANDMARC algorithm and the generalBayesian-based algorithm.
Energy-based Localized Topology Control Algorithmfor Wireless series Ad Hoc Networks
2009, 18(3): 513-518.
Abstract(416) PDF(636)
Extending network lifetime is one of the ultimate goalsof topology control for wireless ad hoc networks. However, most ofexisting topology control algorithms mainly focus on transmissionenergy consumption while fail to consider the residual energy ofnetwork nodes, practically they can not balance energy consumption andprolong network lifetime efficiently. To tackle this problem, wepropose a localized distributed topology control algorithm ELTC(Energy-based localized topology control) for wireless ad hoc networks.Based on the integrated link metric reflecting both the energyexpenditure for sending and receiving and current residual energy oftransceivers, ELTC constructs a dynamical network topology that varieswith node energy. Moreover, without location information, each nodedetermines its transmission power according to the network informationcollected locally, which greatly reduces the implementation complexityand overhead of our algorithm. Theoretic analysis and experimentresults show that ELTC provides routing with an underlying topologywith connectivity and minimum-cost property. Compared with otheralgorithms, it can extend the lifetime of networks more remarkably.
Establishing Multi-Party Trust Architecture for DRM by Using Game-Theoretic Analysis of Security Policies
ZHANG Zhiyong, PEI Qingqi, MA Jianfeng, YANG Lin
2009, 18(3): 519-524.
Abstract(426) PDF(1034)
A successful transaction of digital contents is primarilydependent on security policies, trust mechanisms and benefits balances,as well as the simple adoption of the combination of enhanced securitypolicies would not effectively establish a trust relationship amongvarious stakeholders in the DRM (Digital rights management) -enablingcontents value chain. With respect to a generic DRM ecosystem, thehierarchy analyses of the multi-participant trust architecture wereproposed based on the game-theoretic adoptions of security policies. Byusing formalized definitions of security components and services'utilities, we presented the choice of policies with the externalrelativity, in the contents acquisition scenario, as a multi-playersimultaneous-move game referred to contents provider, digitalservices/rights provider and consumer. Also, in term of securitypolicies combinations' utilities and benefit effects on participants,we further gained the game's Nash Equilibrium, which is a stableprofile of security policies achieving the optimal balance of thesecurity and utilities, thus establishing and strengthening themulti-party trust. The analytic conclusions show that enhancedsecurity policies profile does not necessarily achieve optimal benefitsbalance in the one-stage game, for a small quantity of digital contentstransactions. Whereas, the profile could transform into NashEquilibrium with the increase of transaction sessions, meanwhile beingPareto Optimality.
An Adaptive-Evolution-based Quantum Genetic Algorithm for QoS Multicast Routing Problem
XING Huanlai, JI Yuefeng, BAI Lin, LIU Xin
2009, 18(3): 525-529.
Abstract(382) PDF(775)
This paper investigates least-cost Quality-of-service (QoS) multicastrouting problem in Internet protocol over Dense wavelength divisionmultiplexing (IP/DWDM) optical networks and presents anAdaptive-evolution-based quantum genetic algorithm (AEQGA). Based onAdaptive evolution (AE) mechanism, AEQGA assignsadaptively-adjusted evolutionary parameters to every chromosomeaccording to its own evolutionary situation before each update.Simulation results show that AEQGA is superior to other existingalgorithms and is characterized by fast convergence and effectiveglobal search capability.
Performance Evaluations of an IDMP-based Macro-mobility Management in Heterogeneous Wireless Networks
LIU Xia, JIANG Lingge, HE Chen
2009, 18(3): 530-534.
Abstract(407) PDF(638)
An improved Intra-domain mobility management protocol (IDMP) basedMacro-mobility management (IDMP-MM) mechanism is proposedin heterogeneous wireless networks. It adopts Layer-2 fast handofftrigger, the edge-cells controller to improve intradomain mobility, andthe pre-registration method with the aid of address-table mappingbetween mobility agents to enhance interdomain mobility. The proceduresof intradomain and interdomain handoff in IDMP-MM are describedrespectively, and the performance measurements of IDMP-MM areevaluated. The simulation results show that IDMP-MM mechanism canprovide efficient mobility management to reduce the global signalingcost, the number of buffering in-flight packets, and execute fasthandoff for ongoing calls.
A Balanced Energy Depletion Strategy for the Energy Hole Problem in Wireless Sensor Networks
LIU Yanbing, GUO Wenxu
2009, 18(3): 535-538.
Abstract(471) PDF(610)
Wireless sensor networks suffer from unbalanced energydepletion since sensor nodes sitting around the sink need to carry moretraffic loads and thus would deplete energy faster, leading to what isknown as "energy hole" problem. This phenomenon is due to intrinsicmany-to-one traffic pattern of wireless sensor networks. In this paper,we deploy an analytical model to characterize the "energy hole" problemand describe an iterative process to determine the optimum value of themodel parameters. Then, we propose a balanced energy depletion strategybased on the derived optimal parameters to mitigate the "energy hole"problem. Finally, extensive simulations have been performed to validatethe analysis and the effectiveness of the energy strategy.
Impact of Co-Channel MIMO Interference on Desired Downlink Receiver Using STBC
LI Yongzhao, GAO Xinbo
2009, 18(3): 539-544.
Abstract(426) PDF(533)
The impact of three typical interfering MIMO modes, namely,Space-time block coding (STBC), open-loop spatial multiplexing andclosed-loop spatial multiplexing, on a desired downlink receiverusing STBC is investigated. The closed-form probability densityfunctions of signal-to-interference-plus-noise ratio are derived andused to analyze the performance of the desired receiver. Simulationresults verify the validity of the analytical results. Boththeoretical analyses and simulation results show that these threeco-channel MIMO interfering modes have almost the same impact on thedesired downlink STBC receiver.
On the Similarity Parameter Between Two Targetsfor the Case of Multi-Look Polarimetric SAR
AN Wentao, ZHANG Weijie, YANG Jian, HONG Wen, CAO Fang
2009, 18(3): 545-550.
Abstract(472) PDF(1003)
A similarity parameter between two polarimetriccoherency matrices is proposed based on matrix theory. This parametercan be applied not only to the data case of one-look polarimetricSynthetic aperture radar (SAR), but also to the case ofmulti-look polarimetric SAR. Several properties of the similarityparameter and the analysis on one-look and multi-look polarimetric dataare presented. As an application, target detection for multi-lookpolarimetric SAR case is discussed. Three kinds of improved powermaximization synthesis detector are proposed. Finally, the experimentalresult of target detection is presented and analyzed.
Complex Modes in Parallel-plate Waveguide Structure Filled with Left-handed Material
PAN Yongmei, XU Shanjia
2009, 18(3): 551-554.
Abstract(409) PDF(951)
The parallel-plate waveguide structure partially filled withLeft-handed material (LHM) is carefully investigated. It is shownthat complex mode is the constituent part of complete eigen mode set inthe structure independent of parameters of the configuration andoperating frequency; it means that purely propagating and purelyevanescent mode fields are not a complete set, unless complemented bythe complex mode fields. Numerical results are presented to illustratethe propagation characteristics of present parallel plate waveguide andthe role of complex mode fields in step discontinuity modeling. It isfound that convergence can not be achieved in the mode matchingprocedure unless the complex modes are included in field expansions.
Efficient Design Method for Modified DFT Modulated Filter Banks with Perfect Reconstruction
ZHANG Zijing, YANG Yun
2009, 18(3): 555-558.
Abstract(387) PDF(1207)
This paper presents an efficient iterativeLagrange multiplier approach to the design of Modified discreteFourier transform (MDFT) filter banks with perfect reconstruction. Thedesign is formulated as a quadratic constrained least squaresminimization problem, in which the constraint is reformulated as alinear form at each iteration. This approach is computationallyefficient and particularly suitable for designing MDFT filter bankswith a large number of channels. A MDFT filter bank with 1024 channelsis designed to demonstrate the efficiency of the new method.
Design of Quasi-Elliptic Low-Pass Filter with Single Attenuation Pole Using Defected Ground Structures
YANG Jinping, WU Wen
2009, 18(3): 559-563.
Abstract(422) PDF(998)
This paper presents a design of a microstrip quasi-elliptic Low-passfilter (LPF) with single attenuation pole at finite frequency usingDefected ground structures (DGSs). The designedLPF consists of two Dumb-bell-shaped Defected ground structures(DB-DGS) and a Spiral-shaped Defected ground structure (SP-DGS). Theprototype quasi-elliptic LPF is realized by introducing a capacitiveadmittance inverter into a Chebyshev LPF, and is optimized for the bestcompromise between the pass band insertion loss and the stop bandrejection based on circuit simulation approach. The DB-DGS is used toprovide the required inductance of the LPF, while the SP-DGS is used toprovide the required attenuation pole. Accurate curve-fitting and thesuccessive design approach are given to determine the required size ofDGSs corresponding to the prototype elements. Experimental results of afive-pole LPF for 2.4GHz show that the designed filter has a muchsharper cutoff frequency response than conventional one. A very widestop band from 3.65GHz to 12.7GHz with rejection better than -23dBis achieved. In addition, this filter is only 13.61mm long, which isless than one-sixth wavelength of the microstrip mode at the designfrequency.
An Iterative Frequency Estimation Algorithm Using Generalized Fourier Interpolation
LIU Yanhui, NIE Zaiping, ZHAO Zhiqin
2009, 18(3): 564-568.
Abstract(421) PDF(922)
Motivated by the iterative estimation approach basedon Fourier interpolation in a recent literature, this paper proposes ageneralized interpolation on Fourier coefficients and an iterativefrequency estimation algorithm based on the generalized interpolation.Both theoretical analysis and simulation tests show that the iterativegeneralized Fourier interpolation algorithm converges in two iterationswith the estimation variance only marginally above the AsymptoticalCramer-Rao bound (ACRB) over the entire frequency estimation range.Moreover, the proposed algorithm allows setting different values forits initial parameter. An approach on how to choose the initialparameter is also presented. By using a suggested initial value, theproposed algorithm is much more efficient than the original algorithmin the literature while maintains totally the same estimation accuracy.
A Novel Subspace Approach for Hyperbolic Mobile Location
CHEN Zhangxin, WAN Qun, WEI Hewen, YANG Wanlin
2009, 18(3): 569-573.
Abstract(406) PDF(813)
Locating a Mobile station (MS) in wireless network iscurrently an important research topic. Instead of linearizing thenonlinear hyperbolic equations, a novel noise subspace approach isproposed for hyperbolic mobile location using the Multidimensionalscaling (MDS) analysis whose loss function is related to a scalarproduct matrix. This approach is further improved using the Weightedleast squares (WLS) algorithm. It is robust to large measurement noisedue to the fact that the dimension knowledge and eigen-structure of thescalar matrix are exploited. Computer simulations are included toverify the theoretical development and to contrast the estimatorperformance with the Two-step WLS (TWLS) method and the Cramer-Raolower bound (CRLB).
Adaptive Dwell Scheduling for Digital Array Radar Based on Online Pulse Interleaving
CHENG Ting, HE Zishu, LI Huiyong
2009, 18(3): 574-578.
Abstract(441) PDF(1743)
Digital array radar (DAR) is a kind of phased arrayradar where digital beam-forming technique is used both in receivingand transmitting. An adaptive dwell scheduling algorithm for DAR isproposed based on an online pulse interleaving technique. Furthermore,the scheduling performances of the proposed algorithm with differentsynthetic priority calculation methods are also compared. Simulationresults demonstrate that, compared with conventional schedulingalgorithm the scheduling performance of DAR can be improved effectivelywhen dwells are scheduled with the proposed algorithm, and the Highestpriority earliest deadline first (HPEDF) synthetic priority calculationmethod is suggested in the proposed algorithm.
Visual Computing Method of Radar Cross Sectionfor Target Coating with Plasma
WANG Taosheng, YUAN Lei, WANG Gu, FANG Ning, WANG Baofa
2009, 18(3): 579-582.
Abstract(443) PDF(1539)
A computational electromagnetic model for target coating withplasma is presented, based on the assumption that plasma medium iscold, unmagnetized, collisional and inhomogeneous. In a high frequencyregion, the laminar flow plasma which shields target can be treated aslayered plane media. In each layer, the plasma is equivalent to auniform dielectric. Physics optics (PO) and Impedance boundarycondition (IBC) are applied to calculating the backscattering field,which is implemented by visual Graphical electromagnetic computing(GRECO) method. Numerical results illustrate that the target coatingwith plasma is a valid measure to reduce the Radar cross section (RCS)of target. This conclusion has revealed a broad prospect for plasmastealth and anti stealth.