2011 Vol. 20, No. 1

Display Method:
A Workflow Decomposition Algorithm Based on Invariants
PANG Shanchen, LIN Chuang, ZHOU Mengchu, LI Yin
2011, 20(1): 1-5.
Abstract(580) PDF(765)
An efficient decomposition algorithm for a workflow model based on Petri net invariants is presented in this paper. The algorithm is a new kind of simplification strategy that decomposes a complex and sound Workflow net (WF-net) to a class of simple subnets that are able to describe the business cases. The existence of T-invariants and the coverage sets of WF-net transitions are analyzed and verified in detail. The advantages of the algorithm include its complexity, and avoidance of state space explosion. It can overcome the shortage of the methods based on a depth traversal algorithm. Furthermore, it is readily comprehensible, and can be extended easily to allow parallel processing. The usability of the research results is illustrated by an example.
TransARM: An Efficient Instruction Set Architecture Emulator
CHEN Wei, WANG Zhiying, ZHENG Zhong, XIAO Nong, SHEN Li, LU Hongyi
2011, 20(1): 6-10.
Abstract(549) PDF(830)
Instruction set architecture (ISA) emulation is the key to implement a virtual machine across different ISAs. This paper presents the design and implementation of TransARM, an efficient ISA emulator supporting IA-32 applications on ARM-based systems. TransARM adopts interpretation and binary translation as its basis. Interpretation is performed at the initial stage of emulation. Translation is performed only on the hot spots. Lazy flag updating and Pcache-based hybrid threaded interpretation is used to improve the interpretation performance while superblock chaining is used to accelerate binary translation. Several implementation issues which are crucial in the design of an ISA emulator are discussed, such as the executable and linking format resolution, architecture mapping and system call emulation. Benchmarks selected from MiBench are emulated by TransARM on two real ARM-based systems. Experimental results demonstrate the correctness of TransARM in terms of ISA emulation and indicate that TransARM is competitive to other ISA emulators.
A Formal Specification of Mobile Trusted Computing
HUANG Wenchao, XIONG Yan, CHENG Wenjuan, WU Chengyi, CHEN Depin
2011, 20(1): 11-16.
Abstract(554) PDF(902)
Trusted Computing provides a new way of protecting the mobile nodes from attacks. However, due to the complexity of specification of Trusted Computing and lack of formal methods, the security of mobile software design is still not guaranteed. In this paper, we propose a formal specification of mobile Trusted Computing (TCSpec) by using the B method. TCSpec is a library which encapsulates the Trusted Computing and other secure related operations, and satisfies requirements of most mobile secure software. We give an example of using TCSpec in mobile routing protocols. Moreover, we make analysis and prove that the security of private information is preserved by using TCSpec in design of mobile software.
Multi-path QoS Routing Using Genetic Algorithm for LEO Satellite Networks
RAO Yuan, WANG Ruchuan
2011, 20(1): 17-20.
Abstract(666) PDF(916)
To satisfy the Quality of service (QoS) requirements of multimedia applications, satellite routing schemes should provide better QoS guarantees. A multipath Inter-satellite link (ISL) routing (MPIR) scheme is proposed for low earth orbit satellite networks, which employs genetic algorithm to implement ISL QoS routing. Moreover, several essential ingredients, such as fitness function, mutation probability, are designed. Furthermore, simulated annealing is introduced to handle population diversity. Simulation results demonstrate that MPIR achieves better QoS guarantees than High performance satellite routing (HPSR) on delay jitter, call blocking probability with bandwidth and delay constraints. Besides, ALBR has lower onboard computational requirements than HPSR.
A High-Efficiency Work-on-Demand SoC with a 0.9V/165μW MCU and Dual-Band RF for WBSN
ZHANG Xiaoyu, JIANG Hanjun, CHENG Songyuan, ZHANG Lingwei, LI Fule, ZHANG Chun, WANG Zhihua
2011, 20(1): 21-26.
Abstract(525) PDF(744)
An SoC with a 0.9V/165μW MCU and dual-band RF is presented for Wireless body sensor networks (WBSN). The SoC contains a 403MHz transceiver and a 915MHz receiver, of which the 403MHz band is composed of a 200kbps FSK transmitter and a 64kbps OOK receiver, consuming 5.58mW and 3.13mW, respectively. The 915MHz receiver based on energy harvesting gives the SoC the unique high-efficiency work-on-demand capability, avoiding wasting energy during the idle-listening period. The power consumption of the integrated MCU is only 1/3 of the previous SoC designs in WBSN applications, implementing the on-demand MAC protocol with instant response, satisfying the requirements of medical WBSN applications.
Area Optimization of Fixed-Polarity Reed-Muller Circuits Based on Niche Genetic Algorithm
ZHANG Huihong, WANG Pengjun, GU Xingsheng
2011, 20(1): 27-30.
Abstract(551) PDF(787)
A novel niche genetic algorithm is proposed for area optimization of fixed-polarity Reed-Muller circuits, which may have more than one best polarity. In the algorithm, the niche sources are allocated to a specific number of the most excellent candidates; the niche radius is adjusted according to the real-time information of the evolving process; a flexible memory pool is employed to keep the possibly existed numerous best polarities. Experimental results of eight MCNC benchmark circuits show that the proposed algorithm is superior to the traditional genetic algorithmand the basic clearing algorithmin global searching ability, especially for multi optimal polarities searching.
Genetic Fuzzy + PI Path Tracking Control of a Nonholonomic Mobile Robot
CAO Zhengcai, ZHAO Yingtao, WU Qidi
2011, 20(1): 31-34.
Abstract(518) PDF(1046)
A mobile robot is one of the well-known nonholonomic systems. The genetic fuzzy + PI path tracking control applied to a mobile robot is presented. The proposed controller composes of two fuzzy + PI controllers which are employed to control the angular velocity together, and one fuzzy + PI controller that is utilized to adjust the speed of mobile robot solely. Moreover, the fuzzy controller is designed to track reference path in approaching phase and PI controller is operated to diminish the tracking error in stable phase. In order to obtain better tracking performance, Genetic algorithm (GA) is used to optimize controller parameters. Finally, computer simulation results are given to illustrate the effectiveness of the proposed control scheme.
Wearout Tolerant Network Processing on Asymmetric Multi-core Processor
Peter D. Ungsunan, LIN Chuang, KONG Xiangzhen
2011, 20(1): 35-38.
Abstract(499) PDF(842)
As transistors get smaller and approach technological limits, they suffer from increased susceptibility to failures due to wearout. Future multi-core processors will have many cores, but with decreased service life due to manufacturing variability and high operating temperatures from high power densities. This poses a problem as complex systems with many less reliable cores operate at high temperatures over time, and a small failure can yield unpredictable results in software. However, for network processing applications, processor wearout failure can be mitigated in a gracefully degradable way by taking advantage of the predictable and fault tolerant nature of packet processing. A fault-tolerant asymmetric core arrangement is proposed to improve overall system dependability, useful life and performance, and a SPN model used to predict performability. System throughput and availability is predicted under various loads, as well as long term packet processing behavior.
Research of Cooperative Behavior in Multi-Robots System
PIAO Songhao, ZHONG Qiubo, LIU Yaqi, CAI Zesu
2011, 20(1): 39-41.
Abstract(511) PDF(667)
The overlap of actions selected by each robot results in poor cooperation in multi-agent robotic system, at the same time the conventional reinforcement learning requires a large computation cost because each agent must learn. Using new method to solve these problems, the parametric control and enhancing technique will make the optimal control problem to be transformed into a series of parameter optimization problem, and the decision tree module can accelerate the learning process, so that the reinforcement learning module can choose quickly a proper cooperative behavior. The results of simulation indicate the effectiveness of the proposed method.
A New Way of Test Software for Optimal Software Reliability Estimation
ZHANG Junfeng, CHEN Deyun, WANG Nihong, HONG Bingrong
2011, 20(1): 42-44.
Abstract(522) PDF(672)
With the development of computer application, reliability plays an important role. In this paper, an optimal testing strategy is put forward. At first, a Markov usage model is built up. Second, the testing strategy is described concretely, which includes input data classification, generation of test case and testing strategy. At last, a new method of software reliability estimation is studied, which based on path probability. In order to verify the method effectivity, the emulation experiment is done.
Wireless Network Interface Card Energy Management for Interactive Applications
WANG Jing, GUAN Xuetao, CHENG Xu, CONG Jason
2011, 20(1): 45-50.
Abstract(540) PDF(691)
Power management of Wireless network interface cards (WNIC) plays a significant role in the development of mobile and pervasive computing. However, current WNIC power management often substantially degrades performance or even increases overall energy consumption when used with interactive applications. This paper proposes a WNIC Energy management protocol for latency-sensitive interactive applications(ELIA). ELIA exploits features of user interactions for wireless network energy conservation. The effective user interaction analysis techniques recognize complex sequences of mouse clicks or keystrokes, and provide valuable hints to anticipate underlying network access patterns. The prediction algorithm uses dynamic time wrapping techniques to predict future network access based on those interaction hints, and then adapts power mode of the WNIC according to the prediction. Real-world evaluation results show that ELIA achieves a better balance of the competing goals of energy conservation, interactive performance, and application quality compared with state-of-the-art power management methods.
Floating-Point FPGA Gaussian Elimination in Reconfigurable Computing System
ZHANG Bowei, GU Guochang, SUN Lin, WU Yanxia
2011, 20(1): 51-54.
Abstract(619) PDF(1114)
This paper presents a hardware-optimized variant of the well-known Gaussian elimination and its IEEE-754 single-precision FPGA implementation with highly efficient design, which is worked as an Application function unit (AFU) in a loosely-coupled reconfigurable computing prototype system. In this design, pipelined floating-point operators are employed supported by opensource FPLibrary. The design is mainly composed of uniformly distributed entries, yielding a standalone worst case runtime of O(n2) opposed to O(n3) of the software replication. The results indicate that 15 times-speedup is achieved comparing to the software run by a 2.6GHz Pentium4 CPU with 1GB main memory. To evaluate the hardware, a simple model of reconfigurable system has also been proposed using a Xilinx ML555 board which connects and communicates with a desktop computer via the PCIe port. DMA access method is used for data block transport between host and AFU. To the best of authors’ knowledge, there is no efficient floating-point FPGA for solving Linear systems of equations (LSEs) in the previous work.
Enhancing the Performance of the Organic Light-emitting Device (OLED) by Thermal Treatment
ZHANG Chunlin, ZHANG Yong, LI Haixia, WANG Fangcong, ZHANG Guobing, CHEN Da, JIA Xiaoyun, LIU Su
2011, 20(1): 55-57.
Abstract(550) PDF(1510)
A comparative study on the annealing of the ITO substrates and the organic layers were conducted on Organic light-emitting device (OLED). We fabricated four devices with the structure of Al/Alq3/TPD: PVK/NiO/ITO/Glass, and investigated the effect of heat on device performance by selectively annealing. When the TPD: PVK layers were annealed at 90?C with 30 min annealing time and the ITO substrates were annealed at 300?C with a constant annealing time (100 min). We find the OLED shows obvious performance improvement in brightness and current efficiency, which is attributable to the fact that annealing reduces defects and improves the interface structures of the organics and the organic/ITO interfaces. On the other hand, an appropriate annealing would slow the transportation of the hole, thus finally leads to more balanced electron and hole.
Linear MIMO Transceivers Design with Weighted MMSE Criterion
DAI Jisheng, ZHAO Dean
2011, 20(1): 58-62.
Abstract(594) PDF(627)
With the assumption of perfect Channel state information (CSI) at both ends of wireless link, an optimal MIMO transceivers design with weighted Minimum mean-square error (MMSE) criterion, subject to sum power constraint, is investigated in this paper. Although this problem has been studied in a previous publication, we will show that their solution is optimal only after certain preliminary conditions have been accepted. To fix this gap, new structures of precoder and decoder matrices, as well as an optimal closed-form solution, are derived in this paper. Numerical experiment results demonstrate the effectiveness and robustness of our proposed method.
Linear Canonical S Transform
2011, 20(1): 63-66.
Abstract(498) PDF(909)
In this paper, a linear transform, Linear canonical S transform (LCST), is proposed by generalizing the S transform (ST) with four parameters a, b, c and d, which can provides a time-linear canonical domain representation. It possesses some desirable characteristics that are absent in conventional time-frequency transforms, especially for dealing with the time-varying signals. A fast discrete algorithm of the proposed LCST is also introduced. At the end, a simulation is performed to demonstrate the advantages of the proposed LCST compared with the Linear canonical transform (LCT) and the ST.
Universal Delayed Kalman Filter with Measurement Weighted Summation for the Linear Time Invariant System
GE Quanbo, XU Tingliang, FENG Xiaoliang, WEN Chenglin
2011, 20(1): 67-72.
Abstract(616) PDF(1104)
This paper considers the design of universal delayed Kalman filter for the networked tracking system with arbitrary random delay. Firstly, an equivalent Weighted summation form of the conventional Kalman filter (WSFKF) is given to provide a novel frame to more effectively solve the delayed filtering or Out-of-sequence measurements (OOSMs) estimate. In nature, this form makes perfectly use of the properties of offline parameters computation for Kalman filter and weighted summation of initial state estimate and the ordered measurements, which are respectively from Linear time invariant (LTI) system and Linear minimum mean square error (LMMSE) estimator. Secondly, by combing a replacement with global measurement prediction and a compensation operation based on the innovation of delayed measurement and adaptive online weighted coefficient matrix, a novel universal delayed Kalman filter which is applicable to the arbitrary random delay is designed under the WSFKF frame. Compared with the current delayed filters or OOSMs update methods, the proposed delayed estimator has not only more concise algorithm structure and better estimate accuracy but also stronger application range. The example is demonstrated to validate the proposed delayed estimator in this paper.
IR Object Classification Algorithm Based on Improved Feature Optimum Selection
LIU Jin, JI Hongbing
2011, 20(1): 73-76.
Abstract(560) PDF(630)
To solve the undue sensitivity of Newton iteration to the selection of initial value and the disorder of the features extracted by using ICA (Independent component analysis), an improved algorithm based on fast ICA and optimum selection is proposed for infrared (IR) objects classification. The algorithm conducts one dimension search on the direction of Newton iteration to ensure convergence of search results. Meanwhile, a novel rule is designed for selecting effective classification features according to distance function. Thus declining of classification rate and robustness with the increasing of training samples is eliminated. Experimental results demonstrate that the proposed algorithm can provide higher classification rate with fewer object features and is more robust in different kinds of classes compared with the traditional methods.
Power Control in Body Sensor Networks
HU Siquan, WANG Junfeng, ZHOU Mingtian
2011, 20(1): 77-81.
Abstract(519) PDF(634)
In sensor networks, the selection of the transmission power level influences the network topology, power consumption and packet reception rate. In this paper, we analyze the effects of power control in the scenario of body sensor networks. A joint power control strategy considering both the MAC layer and the routing layer is also proposed. Simulation results show it achieves very good performance on both reliability and power efficiency.
A Comprehensive Interpolation for Medical Slices Based on Combination of Linear and Matching Interpolation
TANG Xiaoying, WANG Liye, LIU Weifeng
2011, 20(1): 82-84.
Abstract(563) PDF(770)
In the process to obtain 3D reconstructed isotropic data volume for medical slices, a comprehensive interpolation for medical slices that combines matching interpolation with linear interpolation is proposed. This method solved the problem that linear interpolation tends to blur the boundaries in interpolated images, whereas matching interpolation is time-consuming. The simulation showed that the comprehensive interpolation method produced clearer boundaries than linear interpolation while it largely reduced data handling compared to matching interpolation.
Separation of Objects with Unclear Edges from the Nonuniform Background
LI Huimin, LIU Shufen, WANG Honghua
2011, 20(1): 85-90.
Abstract(553) PDF(1035)
This paper presents a method for separating objects with unclear edges from the nonuniform illumination background. The paper uses an iterative lowpass filter to estimate the rough background first. And then, objects are located by removing the estimated background from the original image, meanwhile the rough segmentation is worked out too. Next, the primary segmentation output is dilated by means of the iterative lowpass filter again to connect most of the objects together as a larger one. After that, some background points are selected from the dilated image as the control points for image background reconstruction based on B-spline. Finally, the reconstructed background is removed from the original image directly to make the separation. A quantitative evaluation of the performance is also presented in this paper.
Estimating Signal Parameters in Strong Clutter Using SVM-Based Chaos Synchronization
2011, 20(1): 91-97.
Abstract(616) PDF(722)
In this paper, a novel approach for estimating signal parameters in strong clutter using chaos synchronization based on Support vector machine (SVM) is proposed. Assuming that the clutter process is chaotic, chaos synchronization is found to be able to extract the weak signal even when the signal is totally embedded inside the clutter spectrum. When the dynamics of the chaotic system is unknown, an SVM-based chaos synchronization is proposed to estimate the signal parameters. The unbiasedness and efficiency of the proposed approach are evaluated theoretically. Computer simulations on estimating sinusoidal frequencies confirm that the weak target frequencies can be estimated accurately. The proposed method is shown to have a better Mean square error (MSE) performance than the conventional techniques. Apply the proposed method to the narrowband interference cancellation problem in a Spread spectrum (SS) communication system and it is demonstrated that the proposed method can effectively suppress the narrowband interference.
Allometric Power Law Modeling on Brain Chemistry Complexity in Self Stimulus Condition of Calm, Smile, Truth and Lie
LI Wenshi
2011, 20(1): 98-100.
Abstract(547) PDF(716)
Brain chemistry is more important than EEG studies in cerebral mechanism research for endogenous nature. Following brain science study paradigm in self stimulus condition of calm, smile, truth and lie, this paper grasps brain chemistry complexity through neurotransmitters’ super-slow spectrums and their allometric power law features. First, one practical microsystem is constructed based on ARM7-CPU embedded into db4 wavelet analysis in tendem of multy-fractal extracting. Then five subjects are invited and tested in processing near infrared 940 nm otopoint-signals. Nonlinear power law model was extracted in form of Ps = Pc∧a with base-line of calm state, wherein a1 fitted with wavelet analysis signature, and a2 with wavelet analysis in tendem of multy-fractal feature. The interesting results include that a2 means are decreasing basicly in self stimulus condition of smile, truth and lie versus calm. The preliminary conclusion suggests that automatic scorings are feasible for emotion and cognition such as smile, truth and lie versus base-line of calm, in reason of more details mapping brain neurotransmitters and fractal synaptics in vitro.
Multi-layer Cloud Model for Statistically Analysis on Renewable Energy Status in China’s Rural Areas
WU Aiyan, MA Zhonggui, ZENG Guangping, TU Xuyan
2011, 20(1): 101-104.
Abstract(540) PDF(785)
There are three main problems in the modeling process of renewable energy status in China’s rural areas as following. One is how to make a model to adapt to China’s administrative hierarchical system? Another are how to slove the uncertainty of samples and operation between qualitative samples and quantitative samples. According to the problems, we proposed the multi-layer cloud model. It has the characters of multi-layer state space model and cloud model. Firstly it can transfer hierarchically information between neighbouring level, which is suitable for China’s administrative hierarchical system. Secondly, it can solve these uncertainty problems of complicated large system, especially coexistence of fuzziness and randomness, and transformation between qualitative language values and quantitative data. So, we use it to model for statistically analysis on renewable energy status in China’s rural areas, and get a positive result.
Robust Feature Extraction for Speech Recognition Based on Perceptually Motivated MUSIC and CCBC
HAN Zhiyan, WANG Jian, WANG Xu, LUN Shuxian
2011, 20(1): 105-110.
Abstract(618) PDF(732)
A novel feature extraction algorithm was proposed to improve the robustness of speech recognition. Core technology was incorporating perceptual information into the Multiple signal classification (MUSIC) spectrum, it provided improved robustness and computational efficiency comparing with the Mel frequency cepstral coefficient (MFCC) technique, then the cepstrum coefficients were extracted as the feature parameter. The effectiveness of the parameter was discussed in view of the class separability and speaker variability properties. To improve the robustness, we considered incorporating Canonical correlation based compensation (CCBC) to cope with the mismatch between training and test set. We evaluated the technique using improved Back-propagation neural networks (BPNN) in three different tasks: in different speakers, different recording channels and different noisy environments. The experimental results show that the novel feature has well robustness and effectiveness relative to MFCC and the CCBC algorithm can make speech recognition system robust in all three kinds of mismatch.
A Novel Image Enhancement Method for SIFT Feature Extraction of Low Resolution Palmprint Images
LIU Di, SUN Dongmei, QIU Zhengding
2011, 20(1): 111-113.
Abstract(609) PDF(2703)
When using the existing methods to carry out the enhancement of the low resolution palmprint images, Scale invariance feature transformation (SIFT) keypoints used for identification can not be efficiently yield. To solve this problem, this paper proposes a promising local entropy-based Unsharpen Masking algorithm for SIFT feature extraction of the images described above. This method can adaptively improve the contrast of the images to extract SIFT features from palmprint while it does not distort the characteristic of the palmprint texture. The scheme introduces local entropy of the images as the enhancement coefficients. The experimental results show the proposed method can successfully extracts as many as possible SIFT keypoints from the enhanced palmprint images, in contrast to the failure by traditional Unsharp Maskingbased schemes.
Joint Source-Channel En/Decoding Based on a New Symbol-Level Joint Trellis
TU Guofang, LIU Jianjun, ZHANG Can, WANG Qiang
2011, 20(1): 114-120.
Abstract(558) PDF(861)
A joint source-channel en/decoding scheme based on a new symbol -level joint trellis for the Variable length coding (VLC) is presented. In the encoder part, the serial VLC and a Recursive systematic convolutional (RSC) code are treated as a single component code, which is parallel with another RSC code through a quantizer. According to the joint source-channel en/deco- ding model, we construct a new symbol-level joint trellis with compound states by merging a VLC trellis with a convolutional trellis. Based on this joint trellis, the symbol-level a posteriori probability (APP) decoding algorithm is also derived, which leads to a joint iterative decoding approach with symbol-level soft outputs. The experimental results show that the joint source-channel en/ decoding scheme has obtained better performance than existent joint iterative decoding based on the bit-level super trellis. As a result, the proposed scheme obtains 0.70 dB gains after the 8-th iteration at an SER of 10?4, and it provides substantial error protection for variable-length encoded image data.
Iterative Coded Multipulse Pulse Position Modulation for High Data Rate Optical Space Communication
TAN Ying, LIU Wei, GUO Jianzhong, AI Yong
2011, 20(1): 121-124.
Abstract(525) PDF(773)
We present a modulation and coding scheme comprised of the serially concatenation of a convolutional code, interleaver, accumulator, and Multipulse pulse position modulation (MPPM) [or Serially concatenated MPPM (SCMPPM)] for high data rate optical space communication. It is decoded with an iterative demodulatordecoder, using standard turbo-decoding techniques. The Serially concatenated pulse position modulation (SCPPM) has been demonstrated to give the best performance on a space optical link modeled as Poisson channels. We compare the performance of both systems at the same transmission bandwidth and information bits transmitted per modulation symbol on the same link. It is shown that, compared to the SCPPM, the SCMPPM provides better Bit-error rate (BER) performance when operating under a peak power constraint, and is able to achieve higher data rates. Hence, the SCMPPM can be applied to high data rate optical space communication systems where bandwidth and peak power are restricted.
Low Complexity Interference Mitigation for OFDMA Uplink in Time and Frequency Selective Fading Channels
ZHANG Yang, LI Jiandong, PANG Lihua
2011, 20(1): 125-132.
Abstract(542) PDF(739)
This paper investigated the intercarrier interference mitigation for the uplink of an orthogonal frequency division multiple access system in a time and frequency selective fading channel. The proposed algorithm squeezes the interference of subcarrier k into 2τ + 1 neighboring subcarriers by preprocessing the received signal and yields a banded structure interference matrix. Specifically, the value of τ mainly depends on the carrier frequency offsets and determines the squeezing depth which in turn influences the receiver implementation complexity. The proposed scheme exploits this banded structure and realizes a low complexity Minimum mean square error (MMSE) equalizer with iterative soft interference cancellation. Simulation results show that the bit error rate performance of our proposed algorithm approaches the existing full length MMSE equalizer at all signal-to-noise ratio regime with a significant reduction on computational complexity.
CBA-MAC: An Adaptive MAC Protocol over Clustering Based Wireless Sensor Networks
LIU Hao, YAO Guoliang, WU Jianhui
2011, 20(1): 133-137.
Abstract(626) PDF(837)
This paper proposes an adaptive MAC (CBA-MAC) protocol for clustering based wireless sensor networks. In CBA-MAC, sensor nodes are divided into cluster head node and normal node. Cluster head node collects traffic information from normal nodes and calculates appropriate duty cycle according to current traffic, then broadcasts duty cycle information to normal nodes, so sensor nodes can fit for variable traffic occasions well. Furthermore, a proper sleep scheme is also proposed for energy saving consideration. We have implemented CBAMAC in ns-2, and the simulation results show that the energy consumption and latency is reduced well.
Defense Against Objective Function Attacks in Cognitive Radio Networks
PEI Qingqi, LI Hongning, MA Jianfeng, FAN Kefeng
2011, 20(1): 138-142.
Abstract(618) PDF(1357)
Cognitive radio (CR) is a technology for identifying opportunities using the “spectrum holes” for communication by cognition. Consequently, we can increase spectrum resource utilization rate with CR. However, it is cognition that causes an unprecedented challenge for cognitive radio networks, especially in security performance. Based on security problems existing in cognitive radios, we analyze Objective function attacks in detail. To counter this attack, we propose a multi-objective programming model, called MOP, which verifies all parameters tampered, so that attackers can not prevent CR from adapting to surroundings. Our simulation results indicate that theMOP model can defend Objective function attacks effectively. Thus, with the MOP model based on Particle swarm optimization (PSO), cognitive radio networks will obtain the optimum condition.
On Correlation Properties of Boolean Functions
ZHUO Zepeng, ZHANG Weiguo, GAO Sheng, XIAO Guozhen
2011, 20(1): 143-146.
Abstract(528) PDF(693)
The relationship among cross-correlation of arbitrary four Boolean functions is presented. Several known cross-correlation properties of Boolean functions are generalized, and some properties of cross-correlation and auto-correlation are given. Then the relationship between cross-correlation function and the order of resiliency, and the relationship among the sum-of-squares indicator, algebraic degree and the order of resiliency are studied.
Using Mobile Sinks in WSN: Computational Complexity and a Theoretical Bound
GU Yu, JI Yusheng, CHEN Hongyang, ZHAO Baohua
2011, 20(1): 147-150.
Abstract(502) PDF(654)
In this paper, we study the lifetime optimization problem in wireless sensor networks using mobile sink nodes. This problem is inherently difficult since we need to consider both sink scheduling and data routing. Through a simple case study we develop a novel notation named the Placement pattern (PP) to bound traffic patterns with candidate locations. This significantly decreases the number of elements needed to be scheduled. Based on the PP, we mathematically formulate this optimization problem as a Mixed-integer non-linear programming (MINLP), which is very tough and time consuming to solve. By proving that the problem is NP-complete, we point out that instead of seeking an optimal algorithm, heuristic algorithms, especially those with performance guarantee, would be much more desirable to develop. Furthermore, in order to help identify performance gains of heuristic algorithms proposed in the future, we develop a Linear programming (LP) formulation which serves as an upper bound by adopting a reformulation and relaxation technique.
A Quasi-Optimal Probabilistic Fault Localization Algorithm in Communication Networks
LIAO Jianxin, ZHANG Cheng, LI Tonghong, ZHU Xiaomin
2011, 20(1): 151-154.
Abstract(543) PDF(666)
The problem of fault localization, which needs to find the optimal hypothesis from all possible fault hypotheses, is theoretically proven to be NP-hard. In this paper, we propose a quasi-optimal probabilistic fault localization algorithm based on the observation that there are few concurrent faults in real communication systems. A heuristic algorithm is first used to estimate the real number of concurrent faults. According to this estimated number, we then perform exhaustive search over a small specific candidate fault set, in order to obtain the accurate explanation of the observed symptoms. Simulation shows that the algorithm is quasi-optimal, effective and efficient.
Collaborative Localization Method in Wireless Sensor Networks: A Game Theoretic Perspective
HUANG He, SUN Yu-e, XIAO Mingjun, XU Hongli, CHEN Guoliang
2011, 20(1): 155-160.
Abstract(554) PDF(598)
Most of the localization algorithms use neighbor nodes and anchor nodes to refine the position of nodes estimation. Nevertheless, there has not been any paper mentioned the problem of how to refine the position of nodes in a most rational way. The GTCMS (Game theory based confidence mass-spring) algorithm proposed in our paper elegantly solved this problem using game theory. In the position refining procedure of GTCMS, each node first selects the neighbor nodes which will be used to adjust its position by following the natural game course users converge to a Nash equilibrium, and then uses the best response theorem we proposed to adjust its position. We also prove that the GTCMS algorithm could achieve the global Nash equilibrium. Compared with traditional localization methods, GTCMS algorithm greatly reduces the localization error rate and converges much more efficiently.
Research on the Outage Exponent of Superposition Coding Relaying with Only Relay-to-Source Channel State Feedback
JIA Xiangdong, FU Haiyang
2011, 20(1): 161-164.
Abstract(523) PDF(1345)
Based on the canonical three nodes scheme of cooperative relaying, a 2-level rate Superposition coding relaying (SC-relaying) strategy was investigated as well as the outage performance analysis, in which only the relayto- source Channel state feedback (CSF) and a short term power constraint were considered. For the 2-level SCrelaying, besides the optimizing outage exponent of basic signal obtained, the closed form solution of the optimizing outage exponent was also derived through strict math manipulation. The closed form solution is the exact solution of the optimizing outage exponent when the multiplexing gain of basic signal is more than or equal to 0.5 but it is only the approximate lower bound when it is less than 0.5. The numerical analysis show that as CSF introduced a remarkable performance enhancement of Diversity-andmultiplexing tradeoff (DMT) is obtained, which is also increasing with the link feedback resolution K. However, when K > 6 the DMT performance achieves steady maximal value approximately.
An Elliptic Curve Based Handoff Authentication Protocol for WLAN
WAN Changsheng, HU Aiqun, ZHANG Juan
2011, 20(1): 165-169.
Abstract(525) PDF(750)
This paper proposes a novel handoff authentication protocol for WLAN. It uses an elliptic curve based mechanism to design an authentication and key agreement protocol for handoff in the 802.11r domain, and it can effectively defend all known attacks to WLAN including the denial-of-service attack and the domino effect attack. Moreover, our scheme includes only two messages between two parties, and requires few cpu cycles. Therefore, during handoff authentication process, our scheme enjoys both computation efficiency and communication efficiency as compared to the 802.11r authentication scheme.
A Function Migration Algorithm Based on Programmable Router of Multipath Networks
HAN Laiquan, WANG Jinkuan, WANG Xingwei
2011, 20(1): 170-174.
Abstract(480) PDF(696)
According to the unbalanced traffic features and excessive data plane overhead faced by backbone routers, a novel Function migration algorithm (FMA) is proposed. Programmable routers (PRs) are used in FMA. With the router function migration model, PRs set and forward majority traffic through FMA link. Core routers obtain a simplicity function implementation. Theoretic analysis shows that FMA can reduce the forwarding burden and transmission delay. Simulations prove that FMA obtains a lower transmission delay and packet loss rate.
Correlation Characteristics of Channels in MIMO Radar
CHEN Haowen, LIU Yongxiang, YANG Zhaocheng, LI Xiang
2011, 20(1): 175-178.
Abstract(538) PDF(804)
This paper concerns the correlation characteristics of channels in Multiple-input multiple-output (MIMO) radar. We focus on the relation between the antennas spacing and the correlation characteristics of channels considering the extended target and narrow band signals. This paper demonstrates that the higher carrier frequency, larger target, shorter detecting distances and larger antennas spacing will get the lower correlation characteristics of channels in MIMO radar. Simulation results show the conclusion above and the difference between the results from this paper and ones in previous literature.
A Study on Internal Calibration Technology of Spaceborne SAR
LIANG Huaining, LIU Yulong, FENG Jing
2011, 20(1): 179-182.
Abstract(466) PDF(731)
The SAR internal calibration (SIC) technique includes the Internal calibration (IC) theory, IC strategy and highly stable IC instrument. In this paper, the IC technique of a spaceborne SAR system, which employs the TWT (Traveling wave tube) transmitter, is discussed. A method to process the internal calibration data is proposed, the precision analysis of the SIC is given and the effectiveness of the proposed method based on the experimental SAR image is demonstrated.
A Principle of Astronomical Three-dimensional Position Fixing Based on Single Baseline Radio Interferometry
WANG Anguo, LI Hui, WANG Yan, ZHANG Lei, CAO Qingchun
2011, 20(1): 183-186.
Abstract(470) PDF(714)
In this paper, an astronomical threedimensional position fixing principle based on single baseline radio interferometry is proposed. After the basic equations of the principle are derived, the error equations of it are established. Then the computation procedure of software programmed for engineering application is reported. According to the application results, it is testified that the principle proposed can provide a reliable theoretical support for all-weather high-precision three-dimensional position fixing techniques.
Estimating In-pulse Characteristics of Radar Signal Based on Multi-index
HAN Jun, HE Minghao, TANG Zhikai, WANG Jie
2011, 20(1): 187-191.
Abstract(505) PDF(1144)
There are many in-pulse characteristic parameters which can be used for sorting and recognizing radar emitter signals, and they are estimated by right rate usually. For the current electromagnetism environment is composed of compression, complexity and levity, it is not reasonable to estimate the performance of the characteristic parameters only by right rate. Complexity, separability and stability are proposed in this paper to review the performance of radar signal sorting and recognition, and a novel method of estimating characteristic parameters of radar emitter signal is designed. By simulation and analyse, this novel method can estimate the performance of characteristic parameters roundly and accurately, and choose the best parameter for different applied demands.
Preconditioned Bi-conjugate Gradient Method of Large-scale Sparse Complex Linear Equation Group
ZHANG Yongjie, SUN Qin
2011, 20(1): 192-194.
Abstract(521) PDF(1385)
In solving the large-scale sparse complex linear equation group, a lot of CPU operational time and computer memory is consumed to access zero elements of sparse coefficient matrix. As an effective solution, a fullysparse storing scheme is proposed to store only nonzero elements of symmetrical part by chain pattern. For some illconditioned coefficient matrixes, iterative solution methods may incur such problems as slow convergence and even failure of convergence. Fortunately, some valid preconditioning techniques can improve the convergence by reducing condition number of ill-conditioned matrix. Based on a real incomplete Cholesky factorization preconditioner, we develop a fast convergent preconditioned Bi-conjugate gradient method (BCG) to solve the large-scale sparse complex linear equation group. Numerical experiments show that the new incomplete Cholesky factorization preconditioner accelerates the convergence and preconditioned biconjugate gradient method is available for the large-scale complex linear equation group.