Table of Content

25 February 2011, Volume 39 Issue 2

Previous Issue    Next Issue

Electronics, Communication & Automation Technology

Investigation into Voltage-Current Characteristics of ZnO/p-Si Heterojunction Based on Diffusing Models

Xiong Chao Yao Ruo-he Geng Kui-wei

2011, 39(2):  1-6.  doi:10.3969/j.issn.1000-565X.2011.02.001

Asbtract ( 494 )   PDF (759KB) ( 1420 )  

Related Articles | Metrics

 In order to reveal the conduction mechanism of ZnO/p-Si heterojunction,the voltage-current characteristics of the heterojunction in ideal conditions are investigated based on the p-n junction diffusing model and the Anderson diffusing model,and the effects of doping concentration,working temperature and band compensation on the voltage-current characteristics are analyzed.The results indicate that（1） when the forward bias exceeds the built-in potential,the state of most carriers at the two sides of the interface changes from exhaustion into accumulation,thus forming reverse barrier to obstruct the movement of positive electric current in ZnO/p-Si heterojunction;（2） when the applied voltage equals the built-in potential,an inflection point occurs in the voltage-current curve;（3） when the applied voltage exceeds the inflection point voltage,the increasing speed of the current density with the voltage becomes slow;（4） the reverse saturation current density decreases with the increase in doping concentration of p-Si and with the decrease in working temperature,but it is insensitive both to the doping concentration of ZnO and to the conduction band offset;and（5） the applied voltage corresponding to the inflection point is positively related to the doping concentrations of p-Si and ZnO but negatively related to the working temperature and the conduction band offset.

Design of Digitally-Controlled Crystal Oscillator for GSM/EDGE Radio-Frequency Integrated Chip

Chen Xu Chen Xiao-qiang Xu Feng Wang Xin-an

2011, 39(2):  7-11.  doi:10.3969/j.issn.1000-565X.2011.02.002

Asbtract ( 453 )   PDF (1638KB) ( 1365 )  

Related Articles | Metrics

By analyzing the quartz crystal oscillator with the equivalent small-signal model,a digitally-controlled crystal oscillator（DCXO） for GSM/EDGE RF transceiver chips is designed and implemented.DCXO,in Colpitts structure,uses the automatic-gain negative feedback to control the circuit amplitude and adopts a digitally-controlled capacitor array to adjust the stability of transient frequency.The whole circuit is implemented via the TSMC 0.18μm CMOS technology,with a center frequency of 26MHz.Simulated results in the case of 1.8V power supply show that（1） DCXO is of a digitally-controlled range of 123×10-6@26MHz,a regulation accuracy of 0.0075×10-6 per step,a startup time of about 1.5ms and an oscillation peak of about 1.2V;（2） the phase noises respectively reach-145.800dBc/Hz at 1kHz and-153.032dBc/Hz at 10kHz offset;and（3） the total power consumption of DCXO is only 3 mW.

Mixed-sensitivity H∞ robust control for π–type resonant IPT system

Li Yan-ling Sun Yue Dai Xin Yu Kui

2011, 39(2):  12-19.  doi:10.3969/j.issn.1000-565X.2011.02.003

Asbtract ( 514 )   PDF (1116KB) ( 875 )  

Related Articles | Metrics

Based on a non-linear inductive power transfer (IPT) system with π–type resonant network, we applied generalized state space averaging (GSSA) method to achieve frequency domain resolving of time-domain state variables, then real and imaginary parts of the low order fourier coefficients as new variables, approximately, built-up a linear time-invariant system. Comprehensive consideration of parameter perturbation in medium and low frequency as well as uncertainty of un-modeling part in high frequency, an output feedback H∞ robust controller with mixed sensitivity was designed. The weighted functions for multi-objective optimization were adjusted to obtain tracking control without steady-state error and robustness analysis of the load output voltage. The simulation results show that using robust controller, H∞ norm for the closed-loop system’s transfer function reaches to the performance index which is less than 1. In the cases of load parameter perturbation and input voltage disturbance, the system realizes the tracking robust control without steady-state error for the load output voltage, and simulation results verify the feasibility of the proposal.

Two-Stage Decision-Based Detection of Non-Lexical Audio Events in Spontaneous Vocalization

He Qian-hua Li Yan-xiong Li Tao Zhang Hong Yang Ji-chen

2011, 39(2):  20-25,31.  doi:10.3969/j.issn.1000-565X.2011.02.004

Asbtract ( 486 )   PDF (1344KB) ( 1370 )  

Related Articles | Metrics

In order to effectively utilize non-lexical audio events to analyze the semantics of conversational speech,the characteristic differences among the audio events frequently occurring in spontaneous vocalization are analyzed,and a two-stage decision-based method to detect non-lexical audio events in spontaneous vocalization is proposed.In this method,the characteristics of audio events are used to construct signal segments of audio events： the thre-shold decision is used to detect longer applause（the first-stage decision）,and statistical models are employed to detect other audio events（the second-stage decision）.Experimental results show that the average precision,the recall rate and the F1-measure of the proposed method for three non-lexical audio events（i.e.filled pause,laughter and applause） are respectively 87.3%,93.8% and 90.4%;and that,as compared with the existing method,the proposed method is of an average F1-measure increase by 7.5% and it helps to determine the boundaries of non-lexical audio events with higher accuracy.

 Mel-Warping-Based TELPC Algorithm for Estimating Spectral Envelope

Li Ye Yang Jia-wei Liang Yan-xia

2011, 39(2):  26-31.  doi:10.3969/j.issn.1000-565X.2011.02.005

Asbtract ( 467 )   PDF (652KB) ( 1017 )  

Related Articles | Metrics

In order to perceptually enhance the spectral envelope extracted via TELPC algorithm,a new estimation algorithm of spectral envelope is proposed using the property of auditory perception.In this algorithm,the spectral envelope is extracted using a real-time true envelope（TE） estimator and is perceptually enhanced via the Mel-warping.Then,a linear predictive analysis is performed for the warped envelope.Moreover,the warped envelope is compressed to further improve the performance of linear prediction coding（LPC）.The Mel-warping is implemented in two ways： one is by the Fourier transform pair and the other is by the linear interpolation of spectral envelope.Test results indicate that,as compared with the existing TELPC algorithm,the proposed algorithm is more effective because it results in smaller log-spectral distortion and spectral flatness in the low-frequency band,as well as higher performance due to the envelope compression.

Generation of Side Information of Distributed Video Coding at Block Level

Liu Dong Du Ming-hui

2011, 39(2):  32-38,45.  doi:10.3969/j.issn.1000-565X.2011.02.006

Asbtract ( 462 )   PDF (1352KB) ( 1532 )  

Related Articles | Metrics

In order to improve the quality of side information（SI） generated by the motion-compensated temporal interpolation（MCTI） during distributed video coding（DVC）,a scheme to generate SI at the block level is proposed.In this scheme,a mode decision is made at the encoder side,and the macro-blocks in the WZ frame are classified into two modes,namely WZ mode and intra/WZ mode.For the blocks in WZ mode,SI is generated via the MCTI,while for those in intra/WZ mode,high-quality SI is generated by means of motion-compensated quality enhancement（MCQE） after transmitting low-quality intra blocks from the encoder to the decoder.Experimental results demonstrate that the proposed scheme greatly improves the SI quality and achieves an improvement of RD performance up to 2.10dB,especially for strong-motion video sequences and longer length of groups of pictures.

A Fast Motion Estimation Algorithm for Multi-View Video Coding

Zhu Wei Chen Yao-wu

2011, 39(2):  39-45.  doi:10.3969/j.issn.1000-565X.2011.02.007

Asbtract ( 509 )   PDF (912KB) ( 864 )  

Related Articles | Metrics

In order to reduce the computational complexity of multi-view video coding（MVC）,a fast motion estimation algorithm is proposed based on the inter-view and the spatial correlations of motion vectors.In this algorithm,first,the reference motion vector,which accords with the real motion state,is obtained from the motion vectors in neighboring views.Then,the search center is selected from the reference motion vector and the spatial neighboring motion vectors.Finally,the deviation of the search center from the reference motion vector is utilized to adaptively predict the search range.Thus,the computational complexity of motion estimation is effectively deduced.Experimental results show that,as compared with the full search algorithm and the fast search algorithm in the MVC reference software,the proposed algorithm reduces the encoding time by 95.6% and 22.2%,respectively,with the rate distortion performance keeps unchanged.

Orthogonal Adaptive Pulse Design and Performance Analysis of CUWB System

Guo Li-li Zhao Bing Jiang Xiao-fei

2011, 39(2):  46-50,59.  doi:10.3969/j.issn.1000-565X.2011.02.008

Asbtract ( 434 )   PDF (277KB) ( 989 )  

Related Articles | Metrics

In order to avoid the interference of cognitive ultra-wideband systems for the existing narrow-band autho-rized communications systems and improve the spectrum utilization efficiency of cognitive users,a design method of orthogonal multiband adaptive pulse is proposed.In this method,first,the band is divided into multiple subbands and the adaptive emission mask is generated according to channel characteristics.Then,the subband pulses are designed by using the finite prolate spheroidal wave function and are weightedly combined in the time domain.Finally,a group of orthogonal adaptive pulses with flexible handoff spectrum are produced via the Gram-Schmidt orthogonal transformation.Simulated results indicate that,without affecting the authorized users,the produced pulses reduce the termination probability of cognitive users and improve the spectrum utilization efficiency of the cognitive system through releasing the corresponding conflicted bands.

Modified Noble Corner Detection Algorithm Based on Fine Tuning of Local Entropy and Variance

Ma Li-hong Ren Miao Tan Xing-jun

2011, 39(2):  51-59.  doi:10.3969/j.issn.1000-565X.2011.02.009

Asbtract ( 469 )   PDF (2887KB) ( 1054 )  

Related Articles | Metrics

In order to improve the accuracy of corner detection and enhance the ability of false corner suppression,an improved Noble corner detection algorithm based on image entropy and variance is proposed by taking into consideration the differences in statistical characteristics among different regions in gray images.First,the initial refe-rence values of the threshold of corner response function and of the window size for non-maximum suppression are respectively determined.Then,two fine-tuning coefficients corresponding to the two initial values are calculated for each region respectively according to its local entropy and variance.Finally,the reference values are weighted with the two fine-tuning coefficients,and the local threshold and its window size for non-maximum suppression,which adapt to signal structure,are obtained for each region.Experimental results show that the proposed algorithm can accurately locate most true corners and effectively eliminate the interference of false corners.

Segmentation of SAR Images Based on NSCT and FCM Clustering

Sun Ji-feng Deng Xiao-hui

2011, 39(2):  60-64,70.  doi:10.3969/j.issn.1000.565X.2011.02.010

Asbtract ( 530 )   PDF (1701KB) ( 803 )  

Related Articles | Metrics

In order to realize the unsupervised and automatic segmentation of SAR（Synthetic Aperture Radar） ima-ges and improve the accuracy and computational efficiency of segmentation,a segmentation method of SAR images based on NSCT（Non-subsampled Contourlet Transform） and FCM（Fuzzy c-Means） clustering is proposed.In this method,first,a denoising method based on NSCT is used to preprocess SAR images,which may protect the details of texture information.Then,the gray and texture features of SAR images are extracted by an edge-preserving extraction method of gray feature and gray-level co-occurrence matrix.Finally,the improved method of fast determining the clustering number is combined with the FCM clustering algorithm to realize the automatic segmentation of SAR images.Experimental results show that the proposed method is precise and effective in the unsupervised and automatic segmentation of SAR images.

Extraction and Recognition of Iris Features Based on Empirical Mode Decomposition and Singular Value Decomposition

Luo Zhong-liang Lin Tu-sheng Yang Jun Zhao Xiao-fang

2011, 39(2):  65-70.  doi:10.3969/j.issn.1000-565X.2011.02.011

Asbtract ( 592 )   PDF (284KB) ( 1205 )  

Related Articles | Metrics

During the extraction of iris features by the wavelet transform and Gabor filter,the wavelet basis function is fixed and Gabor filter parameters should be optimized.In order to solve these problems,a new extraction method of iris features is proposed based on the empirical mode decomposition（EMD） and the singular value decomposition（SVD）.In this method,first,the preprocessed iris image is decomposed via EMD,and a series of intrinsic mode functions and residual components are obtained to construct the initial feature vector matrixes.Then,the matrixes are decomposed via SVD,and the corresponding singular value is taken as the iris feature vector.Finally,iris features are identified by using a Modest AdaBoost classifier.Experimental results show that the proposed method helps to obtain low-dimension feature vector with higher recognition rate and lower time complexity of feature extraction and matching.

Fast Automatic Localization of Optic Disc in Retinal Images

Zhao Xiao-fang Lin Tu-sheng Li Bi

2011, 39(2):  71-75,80.  doi:10.3969/j.issn.1000-565X.2011.02.012

Asbtract ( 462 )   PDF (1916KB) ( 1503 )  

Related Articles | Metrics

Based on the structure of retinal blood vessels and the features of the optic disc（OD）,a fast automatic method of optic disc localization is proposed.In this method,first,the vertical coordinate of the OD is determined according to the distribution structure of the retinal blood vessel network.Then,the horizontal coordinate is located based on the OD brightness information and the relationship between the OD and the blood vessels.Finally,the OD is limited in a small window with the rough location of the OD as the center,and the OD center is precisely positioned via the Hough transform.By this method,neither prior segmentation of retinal blood vessels nor algorithm training is required.Experimental results indicate that the proposed method is of high localization accuracy and speed.

Least Laxity First Information Scheduling Algorithm of Industrial Ethernet Ring Network

Zhang Yu-hui Li Di

2011, 39(2):  76-80.  doi:10.3969/j.issn.1000-565X.2011.02.013

Asbtract ( 548 )   PDF (369KB) ( 956 )  

Related Articles | Metrics

In order to improve the quality of service of the industrial Ethernet ring network and avoid the frame conflict,congestion and loss,a least laxity first information scheduling algorithm of industrial Ethernet ring network,namely IERN-LLF,is presented.IERN-LLF is proved to be an optimal scheduling algorithm for the industrial Ethernet ring network when all frames are released at the same time.Simulated results indicate that,as compared with the EDF and RM algorithms,IERN-LLF algorithm is of the lowest frame loss rate in the industrial Ethernet ring network,which means that IERN-LLF algorithm is effective in reducing frame conflict,congestion and loss and improving the stability of networked control systems.

A Cloud-Model-based Trust Management Model for Grid Users

Wei Kai Liu Xin-xin

2011, 39(2):  81-87,94.  doi:10.3969/j.issn.1000-565X.2011.02.014

Asbtract ( 496 )   PDF (1868KB) ( 653 )  

Related Articles | Metrics

In the traditional trust management model of grid computing,it is difficult for grid service providers（GSP） to effectively evaluate and manage the trust degree of a huge number of grid users,and to resist Whitewash attack and ensure the safety.In order to solve these problems,a cloud model-based subjective trust management model for grid users is proposed.In this model,the trust degree of users in the grid domain is managed by the user trust agent（UTA）,and GSP only needs to evaluate the trust of UTA with the help of cloud model.Experimental results show that the proposed management model,in accordance with grid architecture as well as with the fuzziness and uncertainty of trust,overcomes the disadvantages of the traditional trust recommendation method and makes the evaluation of trust more accurate and reasonable.

Grid Resource Reservation Policy Based On The Balance Of Benefits And Risks

Ding Chang-song Hu Zhi-gang Hu Zhou-jun

2011, 39(2):  88-94.  doi:10.3969/j.issn.1000-565X.2011.02.015

Asbtract ( 473 )   PDF (270KB) ( 605 )  

Related Articles | Metrics

In order to prevent the violation risk existing in the resource reservation,a novel resource reservation strategy based on the quantified balance between benefits and risks is proposed.The strategy takes into consideration the statistical logs of actual reservation services and uses the utility function to change the multi-objective programming problem of the reservation model into a quadratic one.By solving the quadratic programming problem,a suitable reservation scheme can be determined.Moreover,theoretical analysis is performed to prove the validity and to present the solution to the model,and some simulations are carried out to verify the effectiveness of the proposed strategy in a large-scale simulated grid system.Simulation results indicate that the proposed strategy effectively guarantees the quality of service and provides optimal source reservation strategy according to the risk preferences of different grid services.Thus,the conflict between the reservation violation risk and the resource utilization rate is successfully prevented.

 Fast Handover Scheme of Mobile IPv6 Based on Hierarchical Mobility

Liu Hong-yue Ma Jian-feng Yang Kai

2011, 39(2):  95-99,107.  doi:10.3969/j.issn.1000-565X.2011.02.016

Asbtract ( 353 )   PDF (507KB) ( 1013 )  

Related Articles | Metrics

 In order to improve the performance of fast handover which is a key technology of mobile IPv6,this paper proposes a hierarchical mobility-based fast handover scheme named HMFH.HMFH integrates the micro-mobility with the link-layer trigger,and focuses on such mobile characteristics as handover delay,handover packet loss,scalability and route information.Simulated results indicate that HMFH is an effective handover scheme with short handover delay,low packet loss rate,good scalability and high route efficiency;and that it does not result in the security and reliability degradation of mobile access.

A Side-Channel Attack Method Based on Chosen Plaintext-Timing Difference

Sun Chun-hui Li Hui Yang Yang Lv Chao

2011, 39(2):  100-107.  doi:10.3969/j.issn.1000-565X.2011.02.017

Asbtract ( 478 )   PDF (1564KB) ( 945 )  

Related Articles | Metrics

Proposed in this paper is a side-channel attack method based on chosen plaintext-timing difference.This method,which is called chosen plaintext-timing attack for short and is adopted to evaluate the security of cryptography algorithms,extracts the secret key by selecting a few appropriate plaintexts which are sent to the cryptosystem and by measuring the execution time of the corresponding code,and uses the secret key to attack block cryptosystem and public cryptosystem.Moreover,DES block cipher algorithm is taken as an example to explain the implementation of the chosen plaintext-timing attack.Experimental results on a microcontroller unit indicate that the proposed attack method is effective and practical.In addition,the reason for the execution time diffe-rence existing in cryptosystem implementation is analyzed,and the corresponding countermeasures are presented.

A Reduced SVM-based Fast Intrusion Detection Model

Zhang Xue-qin Gu Chun-hua Wu Ji-yi

2011, 39(2):  108-112,124.  doi:10.3969/j.issn.1000-565X.2011.02.018

Asbtract ( 511 )   PDF (1126KB) ( 1012 )  

Related Articles | Metrics

Owing to the constraints of time and space complexity,the standard SVM（Support Vector Machine） algorithm cannot effectively deal with large-scale network intrusion detection.In order to solve this problem and in view of the geometric interpretation of SVM,an intrusion detection classification algorithm named PCH-SVM is proposed based on the parallel convex hull decomposition and the SVM.With the help of convex hull decomposition and parallel computing,this algorithm can fast extract the vertices of convex hull of the original training samples to build a reduced SVM training set.Experimental results show that the proposed algorithm can effectively reduce the time and space complexity during SVM training,and speeds up the modeling and detection of intrusion detection classifier without any accuracy loss.

Run-Time Malware Detection Based on IRP

Zhang Fu-yong Qi De-yu Hu Jing-lin

2011, 39(2):  113-117.  doi:10.3969/j.issn.1000-565X.2011.02.019

Asbtract ( 551 )   PDF (564KB) ( 897 )  

Related Articles | Metrics

API（Application Program Interface） is widely used to analyze Windows program behaviors for run-time malware detection.However,API call sequences can be manipulated to circumvent detection.In order to solve this problem,a novel method of run-time malware detection is proposed based on IRP（I/O Request Packet）.In this method,n-grams are employed to analyze IRP sequences for feature extraction,and,by combining the negative selection algorithm（NSA） and the positive selection algorithm（PSA） in the artificial immune system（AIS）,n-grams existing only in malicious IRP sequences are selected as detectors.Experimental results indicate that the proposed method outperforms both the NSA and the dendritic cell algorithm in terms of false detection rate and detection efficiency.

Object Recognition Approach Based on Local Type-Consistent k-Means Clustering

Liang Peng Li Shao-fa Qin Jiang-wei

2011, 39(2):  118-124.  doi:10.3969/j.issn.1000-565X.2011.02.020

Asbtract ( 585 )   PDF (2261KB) ( 1656 )  

Related Articles | Metrics

Aiming at the object recognition in complex background,a recognition method,which simultaneously detects object location and classifies object types,is proposed.In this method,first,a large number of interest points are selected from the image and are filtered to obtain exactly-fitted outliers via the epipolar geometric constraint between images.Then,feature codebooks in the interest point space are formed via the local type consistent k-means clustering.Finally,for the given test interest points,the local features are voted to represent the object type,and the foreground object is obtained by maximizing the joint probability of object type and location.Experimental results on standard dataset Caltech-101 and real scene images demonstrate that the proposed method improves the recognition accuracy by about 8%.

Lung Nodule Recognition Combining Rule-Based Method and SVM

Zhang Jing Li Bin Tian Lian-fang Chen Ping Wang Li-fei

2011, 39(2):  125-129,147.  doi:10.3969/j.issn.1000-565X.2011.02.021

Asbtract ( 591 )   PDF (1345KB) ( 918 )  

Related Articles | Metrics

In order to effectively recognize lung nodules in CT images,a recognition method combining the rule-based method and the support vector machine（SVM） is proposed to classify the regions of interest（ROIs）.In this method,first,shape features of candidate ROIs are calculated,and some non-nodule regions are filtered out by using the rule-based method.Then,the remaining candidate ROIs are taken as testing and training samples,whose grayscale and texture features are calculated and used as the inputs of SVM to classify the remaining candidate ROIs.Experimental results show that the rule-based method may result in high possibility of misdiagnosis although there is no nodule omission,while the proposed method combining the rule-based method and the SVM is of low possibility of misdiagnosis but of obvious nodule omission.

Multi-Objective Evolutionary Algorithm Based on Direction Selection Search

Li Xue-qiang Hao Zhi-feng Huang Han

2011, 39(2):  130-135.  doi:10.3969/j.issn.1000-565X.2011.02.022

Asbtract ( 465 )   PDF (2748KB) ( 608 )  

Related Articles | Metrics

When the Pareto solution space is piecewise continuous,the multi-objective optimization algorithm based on the min-max strategy and the pre-set weights may result in the search of the best value by each generation in non-optimal area.In order to solve this problem,a novel judge mechanism is proposed to estimate whether there exists an optimal solution in the Pareto solution space according to the solution set selected in different directions,and the search area is thus adjusted.Moreover,in order to avoid local convergence and prematurity of the proposed algorithm,a direction selection search method based on the external storage mechanism is put forward.Finally,the proposed algorithm is used to test some common multi-objective test functions and some difficult multi-objective test functions in CEC2009 Race.The results indicate that the algorithm is effective.

Adaptive Genetic Algorithm for Undirected Hamiltonian Graph

Hou Ai-min Hao Zhi-feng Chen Xiao-li Shen Dan-hua

2011, 39(2):  136-140.  doi:10.3969/j.issn.1000-565X.2011.02.023

Asbtract ( 451 )   PDF (213KB) ( 1282 )  

Related Articles | Metrics

The two important methods of distinguishing undirected Hamiltonian graphs,namely the backtracking search and the path extension,are both of their own disadvantages.Specifically,the former requires some backtracking operations on path selection,which results in exponential time cost.However,the latter may fail in finding correct answers due to the branch trimming.As any undirected Hamiltonian cycle can always be decomposed into several atomic cycles which are connected with one another by one common edge in a certain order,atomic cycles and basic cycles are used as chromosomes to derive a genetic code with the properties of splicing and decomposing,and a new adaptive genetic algorithm based on the genetic code is proposed to reduce the time cost and guarantee the distinguishing.Experimental results on some real cases demonstrate that the proposed algorithm is effective.

Two-Level Checkpoint Algorithm Based on Dynamic Grouping

Liu Guo-liang Chen Shu-yu Xu Guang-xia Chang Guang-hui

2011, 39(2):  141-147.  doi:10.3969/j.issn.1000-565X.2011.02.024

Asbtract ( 436 )   PDF (283KB) ( 625 )  

Related Articles | Metrics

In order to reduce the overhead of time and space for setting checkpoints,a two-level checkpoint algorithm is proposed,in which the cooperative checkpoint algorithm is adopted for the group level and the single-stage checkpoint algorithm is used for the system level.The algorithm,which is based on the distributed dynamic grou-ping,eliminates orphan messages by sender grouping and implements the change from the conventional two-stage submission algorithm to the single-stage one.Experimental results indicate that the proposed algorithm is of high practicability.The execution time of it is comparatively low and the time complexity for obtaining checkpoints reduces from O（n2） to O（n）.

Reliability Analysis of Replica-Based Peer-to-Peer Storage System

Wang Yu Zhao Yue-long Hou Fang

2011, 39(2):  148-152.  doi:10.3969/j.issn.1000-565X.2011.02.025

Asbtract ( 424 )   PDF (1122KB) ( 790 )  

Related Articles | Metrics

As the node of peer-to-peer（P2P） storage system is unreliable,it is difficult to predict the overall system availability.In order to solve this problem,a method,which models the whole process of system replica management using Markov chain,is proposed.Then,by analyzing the mathematical model,the system failure probability,the time period,the system life cycle and other relevant data are theoretically calculated.Finally,some simulations are performed on the PlanetLab distributed system platform.The results prove that the theoretical calculation is correct.

A New Type of Cayley Graph Model for Interconnection Networks Based on Wreath Product

Zhang Zhen Xiao Wen-jun Wang Xiao-ming

2011, 39(2):  153-158.  doi:10.3969/j.issn.1000-565X.2011.02.026

Asbtract ( 506 )   PDF (236KB) ( 909 )  

Related Articles | Metrics

Proposed in this paper is a new type of Cayley graph model for building large-scale interconnection networks,namely WG2mn,whose node degree is m＋3 when n≥3 and is m＋2 when n=2.A routing algorithm for the proposed model is also presented,and the upper bound of the algorithm diameter is deduced as 5n/2」.Moreover,the embedding properties of the model are analyzed.It is found that WG2mn is superior to other network models because it helps to construct large-scale interconnection networks with lower cost.