Table of Content

31 January 2008, Volume 26 Issue 1

Previous Issue    Next Issue

Articles

Structure Security of Compress Function of SHA-256

LI Chao;WEI Yue-chuan;SUN Bing

2008, 26(1):  1-1 . 

Asbtract ( 2455 )  

Related Articles | Metrics

The paper presents three kinds of variant forms of compression functions of SHA-256, and analyzes security of three variants against the Chabaud-Joux attack compared with SHA-256. The complexity of finding a local collision in SHA-2A is similar to SHA-256,SHA-2B does not exist a low complexity collision, but exist other faults in it’s structure,while SHA-2C is far insecure than SHA-256. Furthermore, a local collision in the vulnerable variant is presented. It follows that the selection of the compression function’s structure highly affects the complexity of the attacks.

Design of Link-State Based Inter-domain Routing Protocol

XIONG Huan;CHEN Ming

2008, 26(1):  6-6 . 

Asbtract ( 1900 )  

Related Articles | Metrics

To improve scalability, convergence and route quality of inter-domain routing, a link-state based inter-domain routing protocol is designed. The status of autonomous system level network is first modeled. Combined with the status information of inter-domain connections, the shortest path algorithm is implemented to calculate the inter-domain route. The routing model and the mechanism of inter-domain routing policy are discussed.The protocol performance is analyzed and compared with BGP. The analysis and simulation results show that the link-state based inter-domain routing protocol can reduce routing table size,and improve convergence and route quality.

Low Complexity Resource Management for OFDM Systems Based on GPS Scheduling

ZHOU Jing;JING Zhi-hong

2008, 26(1):  12-12 . 

Asbtract ( 2379 )  

Related Articles | Metrics

A low complexity resource management scheme based on generalized processor sharing (GPS) scheduling for the downlink of OFDM systems is proposed. By using the MAC-PHY cross-layer design method, the proposed scheme gives a good tradeoff between channel capacities and user fairness. It can achieve fair bandwidth sharing among users by GPS scheduling in the MAC layer, while integrating sub-optimal subcarrier allocation, equal power distribution and adaptive modulation to exploit the available channel capacities in the PHY layer. Furthermore, we propose a weight compensation method to improve fairness of GPS bandwith sharing. Numerical results demonstrate that the scheme offers performance comparable to an existing algorithm, with lower computational complexity.

A Rate Adaptation Mechanism Based on Channel State in Ad Hoc Network

CHENG De-feng;MA Yi-fei

2008, 26(1):  18-18 . 

Asbtract ( 2317 )  

Related Articles | Metrics

An analytic formula of saturation throughput is presented for multi-hop Ad Hoc networks, which takes packet collision and channel conditions into account. Based on the formula, a rate adaptation mechanism is proposed. The scheme can adjust the rate of sending packets exactly, and choose the optimal size of packets to best match channel conditions for maximizing saturation throughput. Simulation results show that the scheme outperforms OAR and 802.11 DCF with 10% and 260% improvement on the saturation throughput and channel-resiliency capability.

Adaptive Shrinkage Image Denoising in Curvelet Domain

DENG Cheng-zhi;CAO Han-qiang;WANG Sheng-qian

2008, 26(1):  22-22 . 

Asbtract ( 2400 )  

Related Articles | Metrics

A nonparametric Bayesian estimator for image denoising in the curvelet domain is studied. A prior model, named normal inverse Gaussian (NIG), is imposed on the curvelet coefficients designed to capture the sparseness of the curvelet expansion. Based on this, a NIG-based maximum a posteriori (MAP) estimator is designed. By estimating the model parameters of curvelet subband coefficients, a MAP-based subband adaptive shrinkage image denoising is realized. Simulation is carried out to show effectiveness of the denoiser. Experimental results show that the proposed method can effectively reduce noise while keep details.

A Novel Histogram Similarity Measure Using Average Translation of Bins

MA Yu;GU Xiao-dong;WANG Yuan-yuan

2008, 26(1):  28-28 . 

Asbtract ( 2348 )  

Related Articles | Metrics

Previous histogram similarity measures have disadvantages when several kinds of deformation happen to the histograms. A novel similarity measure is proposed based on average translation of histogram bins. The value differences of both corresponding and cross bins are calculated to get the average difference against bin distances, and the average translation of bins is used to measure the histogram similarity. Experiments on intensity histograms of images influenced by noise and illumination are carried out to compare the performance of different kinds of similarity measures. The results show that average translation of bins as a histogram similarity measure outperforms other measures under the condition of histogram deformation. It consists with the other measures under general conditions. Preliminary studies on the measure’s usefulness in image retrieval and object searching indicate its potential applications based on image histograms.


Semi-fragile Image Watermarking Based on RS Codes

LIU Cui-Qing;PING Xi-Jian;ZHANG Tao;WANG Yun-He

2008, 26(1):  34-34 . 

Asbtract ( 1941 )  

Related Articles | Metrics

The proposed semi-fragile watermarking scheme is realized using the RS error-correcting codes and wavelet decomposition. While the encoding data of RS codes are composed of an authentication key and selected wavelet data of an image, the checked data of RS codes carry the digital watermark and are embedded into different sub-bands in the wavelet domain of the host image, achieving semi-fragility. Theoretical analysis indicates that the proposed scheme is capable of identifying the authenticators with the authentication key data.

Prediction of Transmembrane Helical Segments in Membrane Proteins Based on Discrete Wavelet Transform

YU Bin;WANG Guang-bin;WANG Yi-fei

2008, 26(1):  40-40 . 

Asbtract ( 2288 )  

Related Articles | Metrics

Increasing protein sequences from the genome project require theoretical methods to predict transmembrane helical segments (TMHs). In this paper, a method based on discrete wavelet transform (DWT) is developed to predict the number and location of TMHs in membrane proteins. PDB coded as 1KQG is chosen as an example to describe the prediction process with this method. Eighty proteins with known 3D-structure from the Mptopo database are chosen at random as the test objects (including 325 TMHs), 312 of which can be predicted and the prediction accuracy is 96.6%. Compared with main prediction results of seven common prediction methods, the obtained results indicate that the proposed method has higher prediction accuracy.

Partial Transmit Antenna Selection for V-BLAST System

ZHANG Xiao-ge;XU Cheng-qi

2008, 26(1):  45-45 . 

Asbtract ( 2186 )  

Related Articles | Metrics

A vertical bell laboratories layered space-time (V-BLAST) system with partial transmit antenna selection is studied. The first layers are separated from the remaining layers by an incomplete QR decomposition. Then, the corresponding antennas are selected according to a certain selection criterion and the first layers are detected. After eliminating contributions of the first layers from the received signals, the remaining layers are also detected. Compared with conventional selection methods, this selection scheme provides multiple trade-offs between complexity and performance according to . Simulation results show that the partial transmit antenna selection retains most of the symbol error ratio (SER) performance of the full selection system. For a 4 transmit RF chains with 4 receive RF chains and 6 transmit antennas, simulation results show that the partial transmit antenna selection based on the max-min criterion can save about 40% up to 92% of the selection time required for the full selection system.


Design and Realization of Harmonic-Suppressed Low-Pass Filter Using Defected Ground Structure

Qi Yu-jie;Liu Xue-guan

2008, 26(1):  51-51 . 

Asbtract ( 2001 )  

Related Articles | Metrics

This paper presents a method to use the equivalent-circuit model and 3-D model simulation for the DGS to extract the dimension parameters. Combining an inter-digital elliptic-function low-pass filter with the DGS structure, a novel filter is proposed. A compensated feed-line structure on the side of the inter-digital elliptic-function low-pass filter is designed, and a couple of suitable DGSs are etched under compensated lines. Furthermore, full-wave simulation and optimization of the proposed filter are obtained with HFSS to get better impedance match. The design gives performances of a flat passband, a wide stopband and a compact structure. Agreement between experimental results and measurements shows validity of the DGS filter, which has good harmonic-suppressed characterizes.

Decision Domain Based Flow-Aware Admission Control

QIU Gong-an;ZHANG Shun-yi

2008, 26(1):  55-55 . 

Asbtract ( 2046 )  

Related Articles | Metrics

To avoid the decision error of single information based flow-aware admission control, four 2D state spaces are established using priority queue length and link fairness rate to describe the information of different link states. According to the flow distribution under different link states, four state spaces are mapped into three integrated decision domains. The integrated decision table based on the integrated decision domain is the decision conditions for proposed admission control algorithm. The formula of blocking probability for real-time flows is derived, and the average throughput for elastic flows obtained. Simulation results show that the proposed algorithm can reduce the delay of real-time flows by 10% and increase the average throughput of elastic flows by 25.75% with approximately 5.44% increase of the blocking probability for real-time flows when overloaded.

Algorithm Management Framework for Data Stream Mining

ZHU Xiao-dong;HUANG Zhi-qiu;CHEN Sheng-qing;HUANG Feng;SHEN Guo-hua

2008, 26(1):  61-61 . 

Asbtract ( 2367 )  

Related Articles | Metrics

In developing algorithms for data stream mining, little work has been done in the management of various algorithms. Although there have been many effective algorithms developed specifically for data stream mining, the application rate is quite low. In this research, we establish a process model for data stream mining. A process model for the algorithm management framework based on web services, PMAMF-DSM, is proposed. We analyze the construction of data stream algorithm repository and the architecture of the framework. Using the framework, a data stream oriented algorithm management system is implemented on Eclipse. Experiments indicate that the framework has high flexibility and self adaptability.

Augmented Reality Registration Algorithm Based on Line Features

ZHAO Xin-can;ZUO Hong-fu

2008, 26(1):  68-68 . 

Asbtract ( 1964 )  

Related Articles | Metrics

A system model of markerless registration with line feature is presented. The complicated registration problem is divided into four steps: feature extraction, matching, 3D reconstruction, and merge of virtual and real scenes. Key techniques and theories in each step are discussed. Using the technique of structure from motion, AR markerless registration is achieved by 3D line tracking. Experimental results indicate that the proposed algorithm is effective.

Mapping from Feature-Based Requirement Model to Agent-Oriented Conceptual Architecture

LIANG Jun-tao;JIANG Xiao-yuan

2008, 26(1):  74-74 . 

Asbtract ( 2103 )  

Related Articles | Metrics

Mapping from requirements to agent-oriented software architecture keep the traceability in concepts between requirements and designs. Make use of feature model, analysis feature dependencies of feature model and dependencies of agent. Then feature exist dependency and feature value dependency are proposed. A mapping approach from feature model to agent-oriented conceptual; architecture is introduced. The approach is illustrated by an example of library management system

Support Vector Date Description Implemented in Class-Imbalance Learning

MIAO Zhi-min;HU Gu-yu;DING Li;ZHAO Lu-wen;PAN Zhi-song

2008, 26(1):  79-79 . 

Asbtract ( 2427 )  

Related Articles | Metrics

In this paper, an I-SVDD algorithm for two-class imbalance problem is proposed, which based on Support Vector Date Description algorithm. In this algorithm, the C value of SVDD with negative sample is redefined for each sample with data distributing information. We verified the efficiency of algorithm using artificial data and UCI datasets for the data unbalanced classification problem. Compared with SVDD with negative samples, the AUC value of I-SVDD is increased by 12%. Compared with AdaBoost, the recall of positive class is increased by 35%,and the precision increased by 2%.

Neural Network Control for Semi-active Suspension Automobile

Qiu Hao;Xiong Zhi

2008, 26(1):  85-85 . 

Asbtract ( 2211 )  

Related Articles | Metrics

Regarding drawbacks of the standard BP algorithm, a high-order derivative based multiple memory BP algorithm is proposed. It combines the n-th order of energy function with the direction of the fastest decline to construct a new direction of the fastest decline, and improve the learning speed of the neural network. The new algorithm is compared with the traditional gradient algorithm to show its high computation speed. Implementation of the new algorithm is given. Finally a neural network controller is designed to optimize the performance of the automobile suspension. The result shows that the new algorithm is convenient and effective.

Adaptive Fuzzy Observer Design for a Class of Nonlinear System

WANG Yong-fu;ZHAO Hong;LIU Ji-ren;CHAI Tian-you

2008, 26(1):  89-89 . 

Asbtract ( 2609 )  

Related Articles | Metrics

We propose a method of adaptive fuzzy observer design for a class of uncertain nonlinear systems. The observer uses fuzzy system to approximate nonlinear functions so that the structure and parameters of the observed object are not needed in the design. The estimation error, approximation error and external disturbance are supervised by a robust term to provide favorable observation performance. This observer is an extension for the nonlinear Luenberger adaptive observer. Effectiveness of the method is proven theoretically and verified in simulation.

Fast Dynamic North-Seeking of FOG Based on Wavelets

LIU Dong-bo;LIU Jian-ye;LAI Ji-zhou

2008, 26(1):  95-95 . 

Asbtract ( 2347 )  

Related Articles | Metrics

Regarding applications of low-precision and medium-precision fiber-optic gyroscope (FOG), we present a fast north-seeking algorithm based on wavelet transform. The proposed method imports continuous slow-speed rotation, changes static measurements into dynamic measurements under the leveling condition. Measurement noise is suppressed, and the useful information of FOG output is kept with wavelet transform filtering. Consequently the influence of FOG’s low-frequency random drifting is reduced. Thus the FOG can find the geographical north fast and accurately. Experimental results show that the method can effectively reduce the time needed to seek north and errors in repetitive north-seeking, and improve direction accuracy. The method is expected to have theoretical and practical values.

Design of Cellular Manufacturing System Based on Matrix Clustering Algorithm

ZHU Heng-yun;YE Wen-hua

2008, 26(1):  100-100 . 

Asbtract ( 2161 )  

Related Articles | Metrics

In recent years, cellular manufacturing system (CMS) is considered as an advanced manufacturing system that can meet variable customer demand, short product life cycle, and increasing worldwide competition. In this paper, a method for designing CMS based on a new matrix clustering algorithm is proposed. Compared to other clustering algorithms such as ROC, ROC2 and DCA in terms of grouping efficiency and grouping efficacy, the method is feasible and with higher efficiency. The elements in machine component matrix are modified from binary to non-binary elements, which provide information of actual intercellular flows of components. This change can provide a more reasonable clustering result than other methods.

Influence of Stretching Fixation on TC4 Ti Alloy Milling Surface Quality

XU Hong-hao;ZUO Dun-wen;ZHU Xiao-xiao;ZHANG Zhen-jin;ZHAO Can;WANG Min

2008, 26(1):  106-106 . 

Asbtract ( 2108 )  

Related Articles | Metrics

Stretching fixation was proposed to improve milling surface quality of TC4 Ti alloy. A plane strain model was developed to analysis the residual stress variation of stretching-fixation milling surface. With a unidirectional mechanical stretching fixture, a stretching-fixation milling experiment was completed on an HSM-600U five axis super-high speed machining center. This was done with the milling speed ranging from 38m/min to 566m/min and the stretching force from 0 to 6330N, and other parameters being kept constant. Surface roughness and residual stress distribution were measured. Experimental results show that stretching fixation has little effect on surface roughness, while increases surface residual compression stress and thickness of residual compression stress layer significantly.