2014 Vol. 23, No. 3

Display Method:
A Population-Membrane-System-Inspired Evolutionary Algorithm for Distribution Network Reconfiguration
ZHANG Gexiang, RONG Haina, CHENG Jixiang, QIN Yanhui
2014, 23(3): 437-441.
Abstract(218) PDF(2001)
Abstract:
This paper proposes a Populationmembrane-system-inspired evolutionary algorithm (PMSIEA), which is designed by using a population P system and a Quantum-inspired evolutionary algorithm (QIEA). PMSIEA uses the population P system with three cells to organize three variants of QIEAs, where communications between cells are performed at the level of genes, instead of the level of individuals reported in the existing membrane algorithms. This work provides a useful framework for synthesizing different algorithms at macro level and exchanging genic information at micro scale. Experimental results conduced on knapsack problems show that PMSIEA is superior to four representative QIEAs and our previous work with respect to the quality of solutions and the elapsed time. We also use PMSIEA to solve the optimal distribution system reconfiguration problem in power systems for minimizing the power loss.
Complex Networks with External Degree
LI Chunfang, LIU Lianzhong
2014, 23(3): 442-447.
Abstract(154) PDF(1456)
Abstract:
The evolvement of complex networks is based on self-contained ultra-large system, but in fact all possible described networks are almost not completeness sub-networks. We study the more complete information description of complex system through introducing autonomous system and external degree, and investigate the statistical properties of external edges. The external nodes, external edges, and external degree provide natural and powerful extension for the traditional network concept of complex physical system, capable of providing more comprehensive information about the connectivity properties of the graph topology. Complex network with external degree provides scalable scale analysis for complex system with as less cost as possible. Experiments reveal that external degree also follows power-law distribution.
Elliptic Curve Quaternary Sequences Constructed Using the Reverse Gray Mapping
WU Chenhuang, CHEN Zhixiong
2014, 23(3): 448-453.
Abstract(138) PDF(1183)
Abstract:
Quaternary sequences are the most important sequences in view of many practical applications. Using the reverse Gray mapping, we propose a new construction of elliptic curve quaternary sequences with strong pseudorandom properties. We apply a result of Marzouk and Winterhof on the relation between the pseudorandom measures for binary sequences and the measures for quaternary sequences to analyze the well-distribution measure and correlation measure of order l, which were introduced by Mauduit and Sárközy, for the proposed sequences.
On l-th NMDS Codes
TONG Hongxi, CHEN Wenhai, YU Fei
2014, 23(3): 454-457.
Abstract(140) PDF(1076)
Abstract:
Linear codes with Singleton defects equivalent to 0, 1, 2 are studied, and they have good properties. They are called MDS codes, NMDS codes, NNMDS cdoes, respectively. In this paper, we study linear codes with large Singleton defects and these codes have same good properties with MDS codes, NMDS codes, NNMDS codes. We call them l-th NMDS codes. A series of iff conditions of l-th NMDS codes is presented. And we give an upper bound on length of l-th NMDS codes. In the last, some examples of l-th NMDS codes are given.
Amended Truncated Union Bounds on the ML Decoding Performance of Binary Linear Codes over AWGN Channels
LIU Jia, MA Xiao, BAI Baoming
2014, 23(3): 458-463.
Abstract(150) PDF(1174)
Abstract:
In this paper, simple upper bounds are derived on the frame and bit error probabilities of binary linear codes over Additive white Gaussian noise (AWGN) channels. The conventional union bound is first truncated and then amended, which can be justified by invoking Gallager's first bounding technique (GFBT). Different from most other works, the "good region" is specified by a suboptimal list decoding algorithm. The error probability caused by the good region can be upper-bounded by the union bounds using pair-wise error probability and tripletwise error probability, which can be further tightened by exploiting the independence between the error events and certain components of the receiving signal vector. The proposed bounds are simple since they involve only the Q-function. The proposed bounds improve our recently proposed bounds. Numerical results are also presented to compare the proposed bounds with the Divsalar bound, which is a simple tight upper bound with closed-form, and the Tangential-sphere bound (TSB), which is considered as one of the tightest upper bounds.
Partition-Based Cache Replacement to Manage Shared L2 Caches
FANG Juan, WANG Jing, LI Chengyan, YAO Zhicheng, KE Weimao
2014, 23(3): 464-467.
Abstract(291) PDF(2313)
Abstract:
The Least recently used (LRU) replacement has been widely employed by on-chip shared caches. With the increase of cache associativity, the performance gap between LRU and theoretical optimal replacement algorithm is significant, motivating us to design alternative replacement algorithms to improve cache performance. We propose a Partition-based cache replacement (PCR) algorithm to manage multi-core shared L2 caches. PCR takes into consideration recency and frequency information of cache access, and cache resource interference among multiple competing applications. PCR is effective to filter out the less frequently reused blocks through a dynamic insertion/promotion policy based on the target partitions, and ensures that some fraction of the working set is retained in the cache to contribute to more hits. Our evaluation shows that PCR improves performance of an 8-core system by an average of 11.3% over LRU-based cache.
Mixed-Level Modeling Methodology for Network-on-Chip Architecture Exploration
YIN Shouyi, ZHANG Zhen, HU Yang, LIU Leibo, WEI Shaojun
2014, 23(3): 468-473.
Abstract(155) PDF(1207)
Abstract:
As Network on chip (NoC) architecture develops as an solution of interconnection in System on chip (SoC) designs, a detailed and flexible interconnection network model integrated in a full system evaluation framework becomes necessary. In this paper, we first present a mixed abstraction level modeling methodology for the performance evaluation of NoC architecture. Then based on our mixed level modeling methodology, we develop a full system mixed-level NoC evaluation and verification platform. Aiming to explore the details of the performance evaluation and hardware verification of interconnection part, we build NoC router at cycle-accurate, bus cycle level and build SoC peripherals at approximately time, bus phase transaction level which intend to gain higher simulation speed, and lower step to relative development of software. The experimental results show that the mixedlevel NoC evaluation platform can achieve both detailed architecture exploration and fast simulation speed.
Constructing Rough Set Based Unbalanced Binary Tree for Feature Selection
LU Zhengcai, QIN Zheng, JIN Qiao, LI Shengnan
2014, 23(3): 474-479.
Abstract(167) PDF(1255)
Abstract:
Feature selection is one of the challenging problems facing data analysis in areas such as pattern recognition, data mining, and decision support. Many rough set algorithms for feature selection have been developed, most of which are essentially dependent on the definite information contained within the lower approximation. This paper proposes a novel approach, called Unbalanced binary tree based feature selection (UBT-FS), which utilizes the indefinite information contained within rough set boundary region for reduction. UBT-FS designs the underlying mechanism for obtaining the boundary region from the unbalanced binary tree and adopts the boundary region based significance for determining the optimal search path as well as the boundary region based evaluation criterion for identifying feature subsets. These allow UBT-FS to have considerable ability in finding an optimal or suboptimal reduct whilst simultaneously achieving obviously better computational efficiency than other available algorithms, which is also supported by the experimental results.
Utilizing Sub-topic Units for Patent Prior-Art Search
ZHOU Dong, LIU Jianxun, ZHANG Sanrong
2014, 23(3): 480-483.
Abstract(151) PDF(1279)
Abstract:
One of the defining challenges in patent prior-art search is the problem of representing a long, technical document as a query. Previously work on this problem has concentrated on single query representations of the patent application. In the following paper, we describe an approach which uses multiple query representations generated from semantically coherent passages extracted from patent documents. We validate our technique in an experiment using the CLEF-IP 2011 patent search collection. Our system achieves statistically significant improvements over various state-of-art query generation techniques.
An Area Weighted Surface Sampling Method for 3D Model Retrieval
LI Haisheng, LIU Xuan, LAI Long, CAI Qiang, DU Junping
2014, 23(3): 484-488.
Abstract(129) PDF(1319)
Abstract:
3D model feature extraction is a key step for geometric content based 3D model retrieval. A 3D model is usually expressed by patches and it has large amount of data. Pseudo-random sequential Monte Carlo surface sampling method is used to sample 3D model data. It has strong randomness. The sampling results are not uniform, which worsen the efficiency and precision of feature extraction. An area weighted surface sampling method for 3DModels is proposed. The larger area patches get the higher probability of sampling. The sampling points are evenly distributed in sampling space, which represent more accurate 3D model features. Experiments show that the proposed method needs less computing resources. Even when there are less sampling points, it can still keep high calculation accuracy and stability.
An Ensemble Colorization Method
LI Lingzhi, ZOU Beiji, ZHANG Xiaoyun
2014, 23(3): 489-493.
Abstract(134) PDF(1151)
Abstract:
Colorization is a well established problem concerning recovering the potential colors of monochrome images. In the past decade several highly effective computer-assisted methods have been proposed for solving the colorization problem, among which two methods achieved the state-of-the-art performance. The two methods are totally different, and each of them has its advantages and disadvantages. We propose an ensemble method unifying the two state-of-the-art methods to better exploit their advantages. Empirical results demonstrate the superiority of our ensemble method over using each of the two methods alone.
An Improved Genetic Algorithm for Test Cases Generation Oriented Paths
MEI Jia, WANG Shengyuan
2014, 23(3): 494-498.
Abstract(247) PDF(1442)
Abstract:
This paper discusses a method that can automatically generate test cases for selected paths using a special genetic algorithm. The special algorithm is called Queen-bee evolutionary genetic algorithm(QBEA). In this algorithm, sequences of operators iteratively executes for test cases to evolve to target paths. The best chromosome called queen among the current population is crossover with drones selected according to a certain crossover probability, which enhances the exploitation of searching global optimum. A comparative experiment results prove that the proposed method is actually a great improvement in optimization efficiency and optimization effect.
A New Method for Sorting Unknown Radar Emitter Signal
CHEN Changxiao, HE Minghao, XU Jing, HAN Jun
2014, 23(3): 499-502.
Abstract(183) PDF(2064)
Abstract:
Sorting rate of common method is not high and it is sensitive to the Signal noise ratio (SNR), in order to solve these problems, bispectrum two dimensions characteristics complexity is applied to sort unknown complicated radar signal and a high sorting rate would be got. The bispectrum of received signal is extracted and it is predigested to two dimensions characteristic, the box dimension and information dimension are extracted from the two dimensions characteristic and used as the sorting characteristics, and the last sorting is accomplished by using KFCM algorithm. For the bispectrum of different signal is distinguishing and it is not sensitive to SNR, the box dimension and information dimension are divisible and steady, the advantage of this new method is validated by simulation results, and the lowest sorting rate is 90% at SNR equals to 10dB.
Multi-dimensional EEF Criterion for Source Number Estimation
HUANG Qinghua, WANG Tong
2014, 23(3): 503-507.
Abstract(118) PDF(1213)
Abstract:
When the number of snapshots is smaller than the dimension of the measured data, Exponential embedded family (EEF) rule fails to choose the correct model order. It is modified in this paper to enumerate sources in three-dimensional space unlimited by the number of snapshots. Then the modified EEF criterion is extended to RD version for the multi-dimensional data model based on Higher-order singular value decomposition (HOSVD). The R-D EEF criterion exploits the multi-dimensional structure of measurements and the eigenvalues of different mode sample covariance matrices jointly. It improves accuracy and robustness compared with the modified EEF criterion. Simulation results demonstrate the performance of the proposed enumerators.
Model and Simulation of Multipath Error in DLL for GPS Receiver
CHENG Lan, CHEN Jie, XIE Gang
2014, 23(3): 508-515.
Abstract(155) PDF(1331)
Abstract:
Although different multipath error models of Delay lock loop (DLL) used in GPS receiver are established, they have never been put together for comparison. Furthermore, no universal simulation method is developed to get a fair comparison among these models. A new model with implicate expression is hence proposed for the coherent DLL and the noncoherent Dot-product (DOT) power mode DLL. Meanwhile, a new simulation method based on the anonymous function in Matlab, which is especially suitable for models with implicit expression, is also proposed to compare the new model with the existing ones. The theoretical analysis and simulation results show that the existing models are the special case of the proposed one. The new simulation method can be used for the comparison of different multipath error models and the multipath error analysis of other DLLs for which only the implicit model is available.
A Feedback Correction De-noising Algorithm Based on the Wavelet Coefficients
LI Ning, CAO Zhen, DENG Zhongliang
2014, 23(3): 516-520.
Abstract(138) PDF(1029)
Abstract:
The localization of satellite interference sources under the condition of low SNR has been a hot research topic at current, where the signal de-noising is important in the following positioning work. With the help of the wavelet analysis theory, this paper proposes a denoising algorithm based on the wavelet coefficients in low SNR. After correcting and reconstructing the signal by the correction coefficients, we could obtain the SNR and Root mean square error (RMSE), and then we could correct the signal for the second time. The simulation results show that this de-noising algorithm can effectively remove the noise of the signal in low SNR, which would have a good effect on the estimation of time delay parameter in the localization of satellite interference sources.
DRA Audio Coding Standard
MA Wenhua, XU Jing, MA Yuanzhe, YOU Yuli
2014, 23(3): 521-526.
Abstract(195) PDF(2348)
Abstract:
DRA (Dynamic resolution adaptation) audio coding standard was shown to deploy transientlocalized MDCT to effectively suppress pre-echo artifacts and statistic allocation of codebooks to improve the compression efficiency of Huffman coding. Its quantizers and Huffman codebooks are designed in such a way that a signal path of 24 bits is provided throughout the codec so that high audio quality can be delivered if bit rate suffices. Although simple, it delivers state-of-the-arts compression efficiency as shown by five rounds of ITU-R BS.11116 compliant subjective listening tests.
A Sound Image Externalization Approach for Headphone Reproduction by Simulating Binaural Room Impulse Responses
XIA Risheng, LI Junfeng, XU Chundong, YAN Yonghong
2014, 23(3): 527-532.
Abstract(212) PDF(1964)
Abstract:
In this paper, an improved sound image externalization approach is proposed by considering the essential differences between headphone listening and reallife listening to deal with the problem of in-head localization of sound images. Through simulating the virtual sound source in a given enclosure, the proposed externalization approach renders sound images out-of-head by exploiting a Binaural room impulse response (BRIR) simulation approach, which consists of a new hybrid approach for the acoustic Room impulse response (RIR) and the Head-related impulse responses (HRIRs). The hybrid RIR simulation approach comprises an improved image-source model for the early reflections by integrating the air absorption, and a Feedback delay network (FDN) for the late reflections. Moreover, the HRIRs are further integrated into each sound image in the early reflections to imitate the effect of listener. Psychoacoustic test results demonstrated that the proposed externalization algorithm offered significant out-of-head perception and more natural quality of sound images.
Combination Rule Based on Proportional Redistribution of Generalized Conflict for Evidence Theory
FU Yaowen, YANG Wei
2014, 23(3): 533-538.
Abstract(110) PDF(1244)
Abstract:
Dempster's rule is a powerful tool for combining multiple distinct pieces of evidence in evidence theory. When conflict between pieces of evidence is high, the combination result of Dempster's rule is counterintuitive. Many alternative combination rules have been proposed. Most of these alternative combination rules are based on the redistribution of Shafer's conflicting mass. The quantitative definition of generalized conflict is given. Based on Proportional generalized conflict redistribution (PGCR), a new class of evidence combination rules is proposed and the links with some existed rules are established. A special instance of the PGCR rules referred to as PGCR-A is proposed by using the subsets' average support degrees as the proportional coefficients. PGCR-A rule can deal with the combination of high conflict evidence. During the process of combination, PGCR-A rule can also automatically determine the weights of the basic belief mass converging to the more specific subsets according to the focal elements' cardinalities. Since PGCR-A rule is not associative, a modified version is proposed to make it quasi-associative.
State Estimation for Linear Constrained Systems with Unknown Input
WEN Chuanbo, CAI Yunze
2014, 23(3): 539-544.
Abstract(142) PDF(1793)
Abstract:
This paper deals with the filtering problem for linear discrete constrained dynamic systems with unknown input. The constraint matrix and constraint vector in this system are allowed to vary in the value and in the dimension. The original full state is separated into two parts, and the estimate of the state is reduced to find the optimal estimate of a singular system. The estimable condition is researched and a recursive estimator for the original full state is presented. A rigorous mathematical induction is given to compare the performance of our approach to that of the existing method without constraint. A numerical example is presented to demonstrate the effectiveness of the new method.
Digital Image Forensics Using Orthogonal 1-D Objects
NIU Shaozhang, MENG Xianzhe, CUI Haoliang
2014, 23(3): 545-549.
Abstract(125) PDF(1187)
Abstract:
The imaging features are shared by all images shot by cameras, the artificial images may break these features. We introduce the image formation model to image forensics. Orthogonal 1-D objects with known scale on either direction are used to estimate the principal point parameter, and the inconsistency of the principal point indicates a forgery. Experiments show that our method can detect cropping and copy-paste efficiently, and it is robust to smoothing, noise and JPEG compression.
Polluted and Perspective Deformation DataMatrix Code Accurate Locating Based on Multi-features Fusion
WANG Wei, HE Weiping, LEI Lei, GUO Gaifang
2014, 23(3): 550-556.
Abstract(157) PDF(1493)
Abstract:
In this paper we present a method for extracting the best candidate edge combination based on multi-features fusion, aiming at the challenges of accurately locating the DataMatrix (DM) code (hereinafter referred to as DM code) with pollution and perspective deformation. Firstly, DM code edges are transformed from image into Hough domain in which linear feature is more prominent. We are able to obtain the valid combinations of candidate marginal points after prior rules-based filtering. Then, we design and extract four boundary features of the finder pattern in image domain. Meanwhile, we establish the model of distorted DM code edge distribution in Hough domain and extract the corresponding features. Finally, we merge the multi-features according to the DS theory and make the final locating based on the fusion result. Compared with traditional methods, the experiments demonstrate the greater robustness and flexibility of our proposed approach to accurately detecting the contaminated Data Matrix coexisted with perspective deformation.
Secure Data Sharing and Retrieval Using Attribute-Based Encryption in Cloud-Based OSNs
HUANG Qinlong, MA Zhaofeng, YANG Yixian, FU Jingyi, NIU Xinxin
2014, 23(3): 557-563.
Abstract(195) PDF(1760)
Abstract:
The Online social networks (OSNs) offer attractive means for social interactions and data sharing, but also raise a number of security and privacy issues. Since the OSNs service provider is always semi-trusted, current solutions propose to encrypt data before sharing. However, data encryption causes a lot of inconveniences and large overheads for data dissemination and data retrieval. In this paper, we propose a secure data sharing and retrieval scheme in cloud-based OSNs. Based on ciphertext-policy attribute-based encryption, our scheme achieves multiparty access control, which allows data owners to outsource encrypted data to the OSNs service provider for sharing, and enables data disseminators to disseminate the data owners' data by customizing new access policy. Our scheme also provides searchable encryption scheme to support fast searches in massive amount of encrypted data from both data owners and data disseminators. Further, our scheme preserves the privacy of data owners and data retrievers during the data sharing and retrieval processes. In addition, the computation overhead of data retrievers is reduced by delegating most of the decryption operations to the OSNs service provider. The security and performance analysis results indicate that our scheme is secure and privacy-preserving.
A Rational Secret Sharing Scheme Against Coalition Based on Nash Equilibrium and Neighbor s Strategy
CAI Cheng, WANG Bojun, Ditta Allah, YANG Yi
2014, 23(3): 564-568.
Abstract(127) PDF(1154)
Abstract:
In order to prevent any arbitrary subsets of coalition in rational secret sharing, we propose a new oneway information transmission mechanism, every player in a rational secret sharing protocol only interacts with his around two players, which means his decision is strictly based on previous neighboring player's strategy. Combined with the punishment strategy of Maleka's scheme and payoff distribution principle in Game Theory, our scheme is capable of achieving Nash equilibrium and has the feature of anti-coalition. For the conspirators, getting the secret at the same time or in less than necessary iteration rounds is almost impossible. Without repeated involvement of the dealer, our scheme has the features of verifiability, anticoalition, and more meaningfully, superiority of approaching reality model by taking rational behavior into consideration.
A Novel Least-Entanglement-Assisted Asymmetric Quantum Codes Based on Sliding Grill
CAO Dong, SONG Yaoliang, ZHU Cheng
2014, 23(3): 569-573.
Abstract(195) PDF(1207)
Abstract:
We propose new methods for constructing novel entanglement-assisted asymmetric quantum codes based on combinatorial designs and sliding grill. Based on a special case of combinatorial designs, our proposed method can construct a type of parity check matrix with greater column weight and better decoding performance. Combined with the characteristic of asymmetric quantum channel, we propose new method of sliding grill. Mother matrix and submatrix can be constructed. The null space of the parity-check matrix gives entanglement-assisted asymmetric quantum code. Tanner graph of the code has a girth of at least 6. Our proposed quantum code has higher code rate with the same error correction capability. These families of entanglement-assisted asymmetric quantum codes consume only one copy of maximally entangled state (ebit), and outperformother quantumcodes based on similar construction method according to our numerical computation.
Network View and Cognitive Mechanism for Virtual Network Resource Management Based Intelligent
WU Xiaochun, WU Chunming, WANG Bin, QIAN Yaguan, LAN Julong
2014, 23(3): 574-578.
Abstract(210) PDF(1684)
Abstract:
Network virtualization has been a particularly important driving force behind the development of NGN. Finding effective ways to control self-adapting virtual networks has become a research hot spot. This paper tries to find an efficient way in combining dynamic resource sensing with traffic character and requirements in virtual network, based on that an intelligent cognition based virtual network resources management model has been put forward. We design a network topology view by coloring network topology matrix with current resources model.We present an intelligent virtual resource management mechanism based on the proposed network topology view. Experiment results illustrate that the proposed mechanism can improve VN capacity by automatic resource adjustment, which can obtain high utilization of VN resources without increasing computational expenses.
HIAWSC: An Immune Algorithm Based Heuristic Web Service Composition Framework
XU Jiuyun, Stephan Reiff-Marganiec
2014, 23(3): 579-585.
Abstract(159) PDF(1002)
Abstract:
The introduction of of web services has led to web service composition being a focus of many researchers. Composing web services using workflows is seen as the most realistic method from an industrial viewpoint. Amongst other method, the use of natural computing methods has been proposed previously to automate web service composition. The need for a fast response when computing the most suitable sequence of services is addressed in this paper. In particular, we propose a novel heuristic immune algorithm with an efficient encoding and mutation method. The algorithm involves two steps: an immune selection operation, which is maintaining antibody population diversity and the clonal selection. The use of a vaccine during the evolution provides heuristic information that accelerates the convergence. Our experimental results illustrate that the proposed heuristic immune algorithm is very effective in improving the convergence speed. We also provide a schema analysis for this method.
Infrastructure-Mediated Sensing Based Home Appliances Monitoring System Using the EMI Characteristics
ZHOU Qiuzhan, CHEN Yongzhi, YOU Ziyue
2014, 23(3): 586-590.
Abstract(126) PDF(1530)
Abstract:
An automatic monitoring system for home appliances using infrastructure-mediated sensing technology is presented. A practical solution for identifying the working states of electronic devices and determining the consumption of each device in a household is proposed. Initially, the components of Electromagnetic interference (EMI) noises in a residential power line are analyzed, and then the basic theory of Switched mode power supplies (SMPS) is discussed. Finally, a set of practical approaches has been proposed to detect and classify the electrical events, including a time-frequency transformation algorithm, power spectrum vector chasing, Gaussian function fitting and supervised pattern recognition, etc. The monitoring system has deployed into real houses and it successfully classifies SMPS devices with accuracy from 92.6% to 99.2% for individual devices and 88.0% to 95.0% for multiple devices.
A Probability Driven Quadri-Stage Contention Protocol for Mobile Ad Hoc Networks
LIU Yun, MA Yongqiang, ZHU Bocheng
2014, 23(3): 591-597.
Abstract(118) PDF(1043)
Abstract:
The paper proposes a new contention based Time division multiple access (TDMA) Medium access control (MAC) protocol in wireless ad hoc networks, which can be termed Quadri-stage contention protocol (QSCP). The QSCP protocol is free of both the "hidden terminal" and the "exposed terminal" problems. It is distributive and arbitrarily scalable. In the dedicated contention stage, nodes exchange their "Normalized accumulation and dissipation rate of payload (NADROP)" messages in 2-hop neighborhood, and then run a contention probability calculation algorithm to decide the probability of sending a contention frame. The algorithm guarantees that the number of time slot reserved by a node is proportional to its NADROP value, which can remarkably improve the end-to-end throughput when network load is heavy, and is more efficient in energy consumption. The simulation results demonstrate that QSCP performs better than the existing protocols.
Metrics in Sharing Video Relationship-Networks
GAO Wen, QIAN Yaguan, WU Chunming
2014, 23(3): 598-603.
Abstract(135) PDF(1811)
Abstract:
At present the video sharing service has gradually became one of the Internet killer applications. It is crucial to the service providers that understand the intrinsic nature of Sharing video relationship-networks (SVRNs) formed by video related list. This paper investigates the relationships between sharing videos using complex networks theory. New metrics are introduced to model and characterize the SVRN from topological view. Through extensive study on YouTube, a set of key findings are revealed. The results show that the node indegree of SVRNs follows the power-law distribution and its entropy remains stable over time. The topology also exhibits an assortative property and obvious clustering phenomenon. But the rich-club phenomenon is not evident compared with the Internet AS-level topology. This research will enable the service providers to optimally plan and operate their video-based services.
A General Description Schema of Services for WSNs
SUN Yan, MA Xiaoqiong, LUO Hong
2014, 23(3): 604-610.
Abstract(123) PDF(1774)
Abstract:
With the rapid development of Wireless sensor networks (WSNs) in recent years, users have been more interested in the services that WSNs can provide rather than data itself. To better bridge between data in different WSNs provided by different developers and comprehensive services required by users, a general service description language used in WSNs is needed. In this paper, we propose a general description schema of services-General service description language (GSDL), which is an XML-like language and can describe simple or composite services. This language makes use of tags agreement, compression and binary coding mechanisms so as to greatly reduce the size of service description document. Moreover, we design a lightweight service composition and decomposition algorithm, which can be executed at each service broker. Compared with widely used WSDL, GSDL is more compact, flexible and suitable for service description in WSNs.
Efficient Two-Dimensional Extrapolation Technique of Scattering Problems Involving Dielectric Objects Using PMCHWT Formulation
LV Zhengliang, GONG Shuxi, ZHANG Pengfei, HONG Tao
2014, 23(3): 611-615.
Abstract(132) PDF(1218)
Abstract:
An efficient extrapolation technique of Radar cross-section (RCS) combines with Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) formulation is presented for the fast analysis by arbitrary shaped threedimensional homogeneous lossy dielectric objects. The PMCHWT formulation obtained in a well-known manner is discretized to matrix equations using the Method of moments (MoM). For the RCS is highly angular dependent as well as frequency, a novel rational function scheme is extended to the induced currents associated with PMCHWT, which can provide fast and accurate radar cross-section computation in both the frequency domain and spatial domain simultaneously. Numerical results are presented for two canonical dielectric scatterers.
Constraint-Guided Methods with Evolutionary Algorithm for the Automatic Test Task Scheduling Problem
LU Hui, NIU Ruiyao
2014, 23(3): 616-620.
Abstract(133) PDF(1016)
Abstract:
The automatic test task scheduling problem is a key challenge for automatic test system to improve throughput and reduce test time. The constrained Test task scheduling problem (TTSP) contains network precedence constraint relationships between tasks. Constrained optimization and topological sorting are applied to handle the constraints. A chaotic non-dominated sorting genetic algorithm is used to stress exploitation ability and obtain high quality solutions. For two commonly applied realworld instances, comparisons show that topological sorting performs much better than constrained optimization and some existing algorithms. Simulation results demonstrate the effectiveness of CNSGA combined with topological sorting for solving constrained TTSP with multiobjectives.
Analysis and Design of Multi-aspect SAR System for Compressive Sensing-Based 3D Imaging
ZHOU Hanfei, SU Yi, XI Zemin, LU Jianbin
2014, 23(3): 621-627.
Abstract(133) PDF(1212)
Abstract:
This paper focuses on the analysis and design of Multi-aspect SAR (MuSAR) system for Compressive sensing-based (CS-based) 3D imaging. For this purpose,the Point ambiguous function (PAF) is proposed to analyze the factors that dominate the Mutual coherence (MC) of MuSAR sensing matrix. The PAF contacts with the parameters and configuration of MuSAR system directly and is easy to manipulate. With PAF, the present study analyzes the factors that dominate the performance of CS-based MuSAR 3D imaging. First of all, the stochastic waveform is an excellent selection. Second, the angular-frequency-diversity can improve the robustness of 3D imaging. Finally, the finer sampling of received data could improve the robustness of MuSAR 3D imaging. Simulation experiments show the validity of conclusion.
Necessary and Sufficient Stability Criterion and New Forbidden Region for Load Impedance Specification
LI Anshou, ZHANG Donglai
2014, 23(3): 628-634.
Abstract(183) PDF(2164)
Abstract:
A necessary and sufficient impedance stability criterion for the DC Distributed power system (DPS) is proposed in small-signal sense, which has no conservativeness when compared with other stability criteria. This paper discusses the stability margin and gives it a definition for the round forbidden region. The reasons why the stability margin varies at different interfaces are also discussed in this paper. With the impedance stability criterion and stability margins considered, the sector forbidden region, which is a new forbidden region and can be easily calculated in the Bode diagram, is proposed to solve the calculation problem of the round forbidden region in engineering application. This paper also provides examples and simulations to verify the necessary and sufficient impedance stability criterion and the proposed sector forbidden region for the load impedance specification.
Research on Secondary Electron Emission Yield Intellectualized Testing System of Space Materials Based on Kingview and PLC
CHANG Tianhai, YIN Peipei
2014, 23(3): 635-638.
Abstract(116) PDF(1353)
Abstract:
This paper describes an intellectualized testing system of the secondary electron emission yield of space materials by combining the technology of electronic control and communication. This system is based on Kingview 6.52 and PLC. The system achieves the document multithreading intellectualized control of vacuum obtaining, pulse modulation of electron gun and on-off of all power sources. The application of Kingview 6.52 makes the design of system more convenient and improves the control quality. The communication with PLC through serial interface improves the ability of data collection and real-time disposing of industry personal computers.
An Adaptive Designing Method of Broadcast Almanac Parameters
WANG Luxiao, HUANG Zhigang, ZHAO Yun
2014, 23(3): 639-644.
Abstract(119) PDF(1164)
Abstract:
A model of the signal acquisition time influenced by the almanac was introduced to evaluate the almanac model. It shows that the six parameters almanac model outperforms the three parameters almanac model. The almanac truncation error was introduced to describe the error between the original data and the interface specification formatted terms. The parameter sensitivity and the truncation error were analyzed to validate the necessity to choose the proper definition of the almanac parameters, including the effective range and the scale factor. It demonstrates the parameter definition is the key designing element while the almanac representation is determined. Based on the research above, An Adaptive almanac designing method (AADM) of broadcast almanac parameters was presented. Simulation results reveal that the AADM can generate an optimum set of almanac parameters with the shortest signal acquisition time to a limited bit allocation.
On Finite Word Length Computing Error of Fixed-Point SAR Imaging Processing
XIE Yizhuang, ZHU Bocheng, YANWen, ZHANG Weijie
2014, 23(3): 645-648.
Abstract(157) PDF(1119)
Abstract:
Synthetic aperture radar (SAR) imaging system is generally realized by fixed-point with the purpose of reducing system implementation scale and enhancing real-time performance. Finite word length computing error of fixed-point SAR imaging system is studied. The characteristic of computing error in SAR imaging system is analyzed. A finite word length computing error model of SAR imaging system is built, by means of which the empirical formula of system's output noise-to-signal ratio is derived. Based on the empirical formula, SAR imaging system processing word length is presented according to different processing granularities. The validity of this proposed finite word length computing error model of SAR imaging system is verified by system level fixed-point simulation.
Automated Landmark Matching of FY-2 Visible Imagery with Its Applications to the On-Orbit Image Navigation Performance Analysis and Improvements
YANG Lei, FENG Xiaohu, LV Ke, SHANG Jian
2014, 23(3): 649-654.
Abstract(150) PDF(1296)
Abstract:
To analysis and improve China Fengyun-2 (FY-2, spin-stabilized geosynchronous meteorological satellite) on-orbit Image navigation (IN) performance, an automated landmark matching algorithm(FY-2 automated landmark matching, FALM) for the Visible and infrared spin scan radiometer (VISSR) visible channel has been developed at China National satellite meteorological center (NSMC). FALM is based on a correlation algorithm used to match the observed landmark to the corresponding landmark extracted from the template. FALM can overcome the previous methods' shortcomings, such as the dependency on ten-year long satellite data and US Defense Mapping Agency data. Each step of FALM, generation of the landmark templates, binarization processing for observed images, image matching between observed images and landmark templates are described. Exclusion of false matching is done by several strict quality measures including cloud contamination detection, prior knowledge check, neighborhood filter and Hypothesis test. 400 days of FY-2 data have been processed by FALM and the results have showed that mainly five factors which can influence the FY-2 on-orbit IN performance: orbit control, the integrity of the known IN parameters, the satellite viewing zone adjustment, beta angle computation and the moment of sunshine pressure. Because of FALM's high processing speed and accuracy, it is ready to put into operation for the FY-2 IN improvement, as well as for operational monitoring purposes, and will be further developed for FY-4.