Table of Content

25 June 2012, Volume 40 Issue 6

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Electronics, Communication & Automation Technology

Detection Algorithm of Pathological Continuous Speech Based on Correlation Dimension

He Qian-hua He Jun Li Yan-xiong Wang Zhi-feng

2012, 40(6):  1-5. 

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As the pre-set optimal sampling delay cannot objectively reflect the signal sampling delay and the fixed correlation dimension is inefficient in describing the complexity of pathological abnormal speech,a detection algorithm of pathological continuous speech is proposed based on correlation dimension ( CD) . In this algorithm,to avoid the defects of pre-set sampling delay,the sampling delay is continuously adjusted within a proper range of sampling delay,and an embedded CD is searched to obtain the minimum equal error rate ( EER) of normal and abnormal speech discrimination. At the same time,the correlation dimension curve is divided into several sub-intervals,and the stability of the sub-intervals is determined to overcome the drawbacks of the fixed embedded correlation dimension. After the EER analysis of the optimal CD sets of the training speech data acquired in a reasonable sampling delay range,the CD with the minimum EER and the corresponding sampling delay are chosen as the chaotic parameters of the proposed algorithm to perform a discrimination of normal and abnormal speeches. Experimental results show that the proposed algorithm possesses a correct classification rate of 75.6%,which is respectively 7. 8%,9. 3%,16.0%,18.0% and 20. 4% higher than those of the GMM-SVM algorithm,the Shimmer algorithm,the fixed CD-sampling delay algorithm,the SHR algorithm,and the Jitter algorithm.

Side-Channel Analysis-Based Detection Approach of Hardware Trojans

2012, 40(6):  6-10. 

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During the fabrication of integrated circuit ( IC) chips in untrusted foundries,malicious circuits may be inserted as hardware Trojans,which results in a significant risk of trustworthiness and reliability degradation of the chips. As such Trojan circuits are difficult to detect using conventional strategies,a nondestructive side-channel analysis-based detection approach is proposed,which employs the algorithm of singular value decomposition to analyze
and statistically process the transient power of IC chips. Validation results of the approach on FPGA chips show that,even in the presence of big noise and process variation,the proposed approach is effective in detecting the hardware Trojans that are 2 orders of magnitude smaller than the original circuit.

Design of Hairpin-Comb Dual-Band Bandpass Filter with Source-Load Coupling

2012, 40(6):  11-15,21. 

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In order to develop dual-band bandpass filters with high selectivity,small size and low cost,a novel method to design the filter with quasi-elliptic response is presented. In this method,two sets of hairpin-comb resonators working at different frequencies are utilized,which provides enough freedom for the independent control of two passbands. The mixed electromagnetic coupling of hiarpin-comb resonators can generate a controllable out-ofband transmission zero,and the source-load coupling can also introduce additional transsmission zeros in the stopband. Therefore,the selectivity and the stopband-restricting ability of the filter are both improved by the transmission zeros caused as much as possible by the combination of these two couplings. A dual-band bandpass filter operating at 2.4 and 5.2GHz is finally designed and fabricated,and the measured results accord well with the simulated ones,which means that the proposed design method is effective.

Implementation of Placement and Routing Improvement for Island-Style FPGA Chips

Li Ming Li Yan Chen Liang Yu Fang Liu Zhong-li

2012, 40(6):  16-21. 

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In order to overcome the loose coupling between FPGA ( Field Programmable Gate Array) placement and routing,an improved placement and routing tool named IVPR is exploited. In IVPR,the directions of logic block pins are considered during the placement to perform a more precise delay forecast,and the possible directions of logic block pins during the routing are predicted to choose an appropriate delay. Thus,the combination between the placement and the routing becomes more effective. Moreover,for the high fanout in the netlist,the net terminal alignment is employed during the placement and the longline-priority strategy is adopted during the routing. Tested results on an island-style FPGA chip VS1000 show that,as compared with the typical placement and routing tool VPR,IVPR reduces the circuit delay by 16.4% and increases the routing resource utilization by 1.9%.

Rate Allocation Based on Pricing Function of Cooperative Access to Wireless Random Networks

Liu Jiao-jiao Cao Yan

2012, 40(6):  22-28. 

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In wireless random access networks,high-speed cooperative transmission can be implemented via the rate allocation that distributes the traffic flow to heterogeneous networks. However,both the collision probability and the average waiting time may increase with the number of competitive hosts. In order to solve this problem,a rate allocation algorithm based on the pricing function of cooperative access to the network is proposed,which
describes the access time cost with the pricing function based on the channel utilization and models the rate allocation according to the principle of achieving the maximum total network payoff with the minimum access cost. The abovementioned rate allocation problem is proved to be a convex optimization one and the explicit solution to the problem is obtained according to the Lagrange multiplier method. Simulated results show that the proposed algorithm helps to select the access networks and distribute the traffic to networks according to both the network status and the channel
efficiency,and that it makes a trade-off between the access delay and the fairness. Moreover,it avoids the access to heavy-load random access networks,thus increasing the access efficiency.

Fast Algorithms for Cross-layer Optimization in Wireless Mesh Backhaul Networks

Luo Mao-song Ye Wu Feng Sui-li Zhang Wei-qing

2012, 40(6):  29-35,42. 

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Proposed in this paper are two fast algorithms for the cross-layer optimization of routing and scheduling in the TDMA ( Time Division Multiple Access) mode in wireless mesh backhaul networks. The first algorithm,which is based on the maximal clique search and introduces a cross-layer optimization model with the minimum system activation time as the optimization target,enumerates all maximal concurrent transmission scenarios in the network by using the Bron-Kerbosch maximal clique searching algorithm,and it simplifies the optimization framework. Thus,the system scheduling time can be minimized via the linear programming and the computation can be remarkably speeded up. Simulated results indicate that, as compared with the classical column generation algorithm,the first algorithm reduces the average runtime by more than 99%. Furthermore,the second algorithm,which is proposed according to the flow characteristics of wireless backhaul networks,is a fast heuristic algorithm based on the
classification of link weights. It can find out the concurrent transmission scenarios that include high weight links with high probability. Simulated results show that the second algorithm helps to obtain suboptimal results with a bias ratio being less than 0.5% from the optimality for the networks with 35 nodes,and the average runtime is only about 2.5% of that of the first algorithm.

Improved DV-Hop Localization Algorithm Based on Optimal Communication Radius of Nodes

Wu Yu-cheng Li Jiang-wen

2012, 40(6):  36-42. 

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In order to reduce the positioning error of the existing DV-Hop localization algorithms in wireless sensor networks with randomly-distributed nodes and to avoid the additional communication overhead of the existing improved methods,an improved DV-Hop localization algorithm based on the optimal communication radius of nodes is proposed. In this algorithm,the optimal communication radius of nodes is calculated by analyzing the distribution characteristics of the nodes in the network,and the optimized distribution scheme of the anchor nodes insensitive to disturbance is obtained through an error analysis. Then,the average hop distance of the anchor nodes is corrected via the least square method,and the positions of unknown nodes are finally optimized via the weighting method. Simulated results show that,as compared with the existing algorithms,the proposed algorithm is of higher locating accuracy without any additional network traffic.

Video Segmentation Algorithm Based on Partitioning-Processing Conditional Random Field

Sun Ji-feng Ouyang Jin-hua

2012, 40(6):  43-47. 

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In order to reduce the time complexity of the traditional video segmentation based on the conditional random field ( CRF) ,a partitioning-processing algorithm is proposed. In this algorithm,the spatial correlation of pixels is used to partition the original frames into some new ones that are then segmented by the CRF,and the final segmentation is realized according to the initial segmentation,the results of the previous frame and the results of the current frame after CRF segmentation. Experimental results show that the proposed algorithm effectively reduces the time complexity without obvious increase in the false rate of video segmentation.

Real-Time Sorting Algorithm of Spike Potentials Based on Probabilistic Neural Network

Zhu Xiao-ping Han Ye-qiang Hao Yao-yao Wang Dong Chen Yao-wu

2012, 40(6):  48-55. 

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In order to develop a portable brain-machine interface ( BMI) for practical real-time applications,a realtime sorting algorithm of spike potentials based on the probabilistic neural network ( PNN) is proposed and is implemented on the FPGA ( Field Programmable Gate Array) . In this algorithm,the network is trained via the quick loading of training data,and the spike potentials are sorted out through the trained network. In the FPGA architecture,a floating-point multiply-add operation is implemented by a on-chip DSP48Es; the calculation of vector distance is accelerated by adopting a pipelined parallel architecture; and the lookup table as well as the CORDIC ( Coordinate Rotation Digital Computer) method is employed to achieve an accurate approximation of the PNN activation function. Experimental results show that the FPGA-based implementation of PNN runs 47.43 times faster than the Matlab-based one with the same accuracy being up to 93.82%,which means that the portability and the real-time processing of BMI are successfully realized.

Human Action Recognition by Using Polyhedron Model-Based Spatio-Temporal Gradient Descriptor

Yao Li-xiu Wang Xiao-nian Yang Jie Liu Jia

2012, 40(6):  56-62,69. 

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In order to detect the spatio-temporal interest points that illustrate the characteristics of human action and possess robustness to noise and camera zooming,first,a novel detector for spatio-temporal interest points is proposed. Next,by centering on the detected spatio-temporal interest point,a polyhedron model-based spatio-temporal gradient descriptor is created to illustrate the spatio-temporal visual features of human action. Then,a larger and more efficient codebook of video action clips is constructed by using the Bag of Words method based on the hierarchical vocabulary tree. Finally,by integrating the descriptor with the high-level action attributes defined by human,the latent support vector machine combined with coordinate descent is adopted to find the local optimum of the prediction model. Experiments on some typical databases demonstrate that the proposed method achieves high recognition rate of human action.

Memory State Feedback-Based Model Predictive Controller of Time-Delay Systems with Input Constraints

Qin Wei-wei Liu Gang Zheng Zhi-qiang

2012, 40(6):  63-69. 

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Proposed in this paper is a model predictive controller ( MPC) based on the memory state feedback,which is developed for discrete-time uncertain linear time-delay systems with input constraints. In this MPC,a robust performance index is defined,and the feedback control law with time-delay state is presented by taking into consideration the influence of time-delay state. During the online optimization,the current control variable is taken as an independent decision variable and is separated from the rest of the control variables governed by the feedback law. Thus,the conservatism of the algorithm is deduced and the feasibility of the algorithm is improved. Moreover,the control strategy of the convex optimization based on the linear matrix inequality and the sufficient condition of system stability are presented,and a simulation is finally performed to verify the effectiveness of the proposed algorithm.

Efficient Reinforcement-Learning Control Algorithm Using Experience Reuse

Hao Chuan-chuan Fang Zhou Li Ping

2012, 40(6):  70-75. 

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Though eNAC ( episodic Natural Actor-Critic) algorithm,an episode-based reinforcement learning control algorithm,is theoretically of excellent learning performance,it is inefficient in learning because many episodes are required to obtain a good policy. In order to solve this problem,a new algorithm named ER-eNAC,which introduces the episode reuse mechanism in eNAC algorithm,is proposed. In ER-eNAC,some of the past episodes are
reused in the estimation procedure of current natural policy gradient for the purpose of using the experience more efficiently,and the reused episodes are weighted in an exponential decay according to the number of policy updates that they have undergone for the purpose of describing their fitness to the current policy. The proposed algorithm is then applied to the inverted pendulum control. Simulated results show that,as compared with eNAC algorithm,ER-eNAC algorithm is more effective because it significantly reduces the number of episodes for learning and remarkably improves the learning efficiency.

Design of Hierarchical Hybrid Virtual Prototype of MAV Flight Control System

2012, 40(6):  76-83. 

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In order to overcome the problems existing in the traditional design method of micro air vehicles ( MAVs) ,such as long period,high cost and low efficiency,a design environment of virtual prototype of the flight control system ( FCS-VP) is constructed. In this environment,the FCS-VP of a MAV, which is in a hybrid three-layer structure consisting of a task-scheduling layer,an action-planning layer and a basic regulation layer,is designed with SysML and Simulink. Simulation results demonstrate that the designed FCS-VP well simulates the FCS of MAV in terms of structure,f unction, behavior and performance,supports the further model-driven development of flight control software and improves the efficiency of MAV design.

Probability-Based Bandwidth Reservation Strategy for LEO Satellite Networks with Multi-Class Traffic

Chen Li-Ming Guo Qing Yang Ming-Chuan

2012, 40(6):  84-89,96. 

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In order to maintain users’smooth connection to satellites during frequent handovers in LEO ( Low Earth Orbit) satellite networks with multi-class traffic,an adaptive probability-based bandwidth reservation strategy ( APRS) is proposed. Based on the deterministic and predictive features of the movement of mobile users APRS reserves the bandwidth without full amount for coming handovers and according to the handover probability of mobile users and adaptively adjusts its reservation according to the current network condition. Moreover,the implementation methods of APRS in multi-class traffic environment are proposed,and the effectiveness of it is verified via simulation. The results indicate that APRS can reserve and allocate appropriate bandwidth for users in multi-class traffic environment,provide users with satisfactory quality of service ( QoS) and increase the bandwidth utilization.

A Robust DOA Estimation Algorithm Under the Condition of Unknown Number of Signal Sources

Zhou Qing-chen Gao Huo-tao Wang Fan Shi Jie

2012, 40(6):  90-96. 

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As the existing DOA ( Direction of Arrival) estimation methods are all based on ideal circumstances,their performance may highly degrade when they are applied to practical situations with small snapshot number and certain array error. In order to solve this problem,this paper proposes a robust DOA estimation algorithm under the condition of unknown signal source number. In this algorithm,the data received by the array are pretreated via the
projection transformation to inhibit model errors and reduce data dimension,thus improving the robustness and lightening the computation load. Then,the DOA is estimated according to the transformed m-Capon spatial spectrum function. Simulated results indicate that the proposed algorithm outperforms the MUSIC algorithm and the diagonal loading m-Capon algorithm because it is of certain super-resolution ability and strong robustness even in the direction finding with short snapshot and small system error ( being less than 10%).

Computer Science & Technology

Implementation of Extended Instruction Set for AES Fast Algorithm

Feng Bin Qi De-yu

2012, 40(6):  97-102. 

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Based on Daemen’s AES fast algorithm,two schemes of implementing the instruction set extension on configurable processor NiosII are proposed to achieve hardware acceleration. These two schemes,one of which stores lookup table in on-chip memory and the other uses a logic circuit to realize the S-box and calculates the corresponding elements of the lookup table,employ a forward lookup table to replace the intensive round transformation
operation. Specifically,the forward lookup table of the fast algorithm is placed in on-chip memory,12 new extended instructions are created to achieve the key expansion,the round transformation and the last round transformation,and the S-box used in the last round is obtained by masking the forward look-up table. In order to eliminate the on-chip memory usage,the schemes are then optimized by deriving the logical relationship between the S-box and the forward lookup table and by employing a logic circuit to realize the S-box via the inverse finite element method. Thus,the system security is enhanced and the power consumption is reduced. Finally,the performances of the extended instruction sets,the coprocessor and some other schemes are tested and compared. The results show that,as compared with the pure software solution of AES fast algorithm with optimized structure,the proposed schemes increase the speedup by 247% only with 223 additional LEs.

A Fast Algorithm for Approximate Pattern Matching

Li Yong-jun Ao Dao-gan

2012, 40(6):  103-108. 

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In order to improve the performance of the dynamic programming algorithm,a traditional method of solving the approximate pattern matching problem, a novel filtering-type approximate pattern matching algorithm is proposed,which combines the advantages of the dynamic programming algorithm, splits the pattern string into smaller pattern pieces with the same length,divides the text string to be matched into sub-strings and further establishes the corresponding index. Moreover,a new filtering strategy is proposed to eliminate the redundancy of the match examination. Example results show that the proposed algorithm is superior to the existing ones due to its small match time cost and high performance,especially under the condition of long pattern string matching; and that,as compared with the traditional dynamic programming algorithm,the proposed algorithm reduces the match time by more than 50% when the pattern string length is more than 45.

Dtrie-allpair: an Efficient Set T-Overlap Join Algorithm

Jin Lian-Yin Xi Jian-Qing Li Meng-Juan You Jin-Guo Liu Yong Miao De-Cheng

2012, 40(6):  109-117. 

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As the traditional T-overlap join algorithms generate a huge number of candidates and thus degrade the system performance inevitably,a dynamic trie-based index,DTI,is designed. Based on DTI,a novel similarity join algorithm named Dtrie-allpair is proposed. Dtrie-allpair helps to directly obtain join results without generating candidates and avoids additional overhead. Then,the effects of the order of records in the database and the order of elements in the records on the performance of Dtrie-allpair are investigated. Some experiments are carried out on msweb and msnbc to compare Dtrie-allpair with such algorithms as All-pair and PPJoin. The results show that ( 1) Dtrie-allpair obviously outperforms All-pair and PPJoin,especially at low overlap thresholds; ( 2) at an overlap threshold of 2,the efficiency of Dtrie-allpair is about two orders of magnitude higher than that of All-pair and
PPJoin; ( 3) the preprocess of the dataset with the combination of frequency-descending order and length-ascending order greatly reduces the number of accessed trie nodes and significantly improves the efficiency of Dtrie-allpair.

Cross-Layer Directed Diffusion Routing Algorithm Based on Cayley Graph

Li Lan Wen-jun

2012, 40(6):  118-125. 

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In order to improve the energy utilization of wireless sensor networks,a fixed-channel allocation protocol is designed in MAC layer via the graph embedding,based on which the directed diffusion routing protocol is improved through a cross-layer approach,and a cross-layer directed diffusion ( CLDD) routing algorithm is presented based on the Cayley graph. In the presented graph embedding method,the Cayley graph is used as the logical topology with vertex symmetry and with a network diameter of O( log₂N) ,which simplifies the next hop routing and shortens the average routing length and,furthermore,improves the integrity and robustness of the system. Simulated results indicate that CLDD algorithm is superior to the directed diffusion algorithm and the Omniscient Multicast algorithm in terms of energy consumption and transmission delay.

Dynamic KaaS Combination Strategy Based on Multi-Objective Ant Colony Optimization

Jia Rui-yu Wu Zhang-jun Zhang Yi-wen

2012, 40(6):  126-131,158. 

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In order to implement the knowledge sharing and integration in the form of Web services in cloud computing environments,a KaaS ( Knowledge as a Service) combination strategy based on multi-objective ant colony optimization is proposed. In this strategy,a dynamic KaaS combination model, which takes into consideration the dynamic characteristics of cloud computing environments and the QoS ( Quality of Service) rules of KaaS,is established from the viewpoint of knowledge service provider. Then,by redesigning the corresponding pheromone and heuristic information of the ant colony algorithm,the features of the problem are used to guide the searching process,and the multi-objective optimization is thus achieved. Finally,a simulation is conducted with real Web services on the cloud computing platform. The results indicate that,as compared with the strategies based on the genetic algorithm and the coevolution algorithm,the proposed strategy is more effective in terms of performance and solution quality.

Architecture & Civil Engineering

Analysis of Nonlinear Seismic Response of Cable-Stayed Bridge Subjected to Longitudinal Strong Ground Motions

Xu Yan Duan Xin-zhi Li Jian-zhong

2012, 40(6):  132-138. 

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This paper deals with the seismic performance of cable-stayed bridges subjected to longitudinal strong ground motions,with one typical medium-span cable-stayed bridge as the research object. In the investigation,the linear seismic capacity-to-demand ratio of the bridge is determined,based on which different types of nonlinear electroplastic elements are introduced to reveal the plastic behaviors of the main bridge components as well as their effects on the whole-bridge seismic response. The results show that ( 1) under strong ground motions,the plastic behaviors of the bridge tower and the piers correlate with not only the characteristics but also the intensity of seismic waves; ( 2) the bridge tower may yield before the auxiliary and the side piers do; and ( 3) the yielding of the bridge tower results in a significant reduction of seismic-induced moment of tower columns. Therefore,in strong earthquakes,it is necessary to take into consideration the nonlinear seismic response of the bridge tower and its effect on the seismic performance of the whole bridge. Meanwhile,in current practical design,the bridge tower and piers may still conserve certain plasticity margin under longitudinal strong ground motions.

Calculation of Construction Period Value-at-Risk of Foundation Pit Engineering for Subway Station

Liu Xin Hong Bao-ning Han Shang-yu Chen Xing-zhuan

2012, 40(6):  139-144. 

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This paper deals with the calculation methods and the corresponding steps of the value-at-risk due to the construction period change,based on the total probability and the Monte Carlo thoughts. In the investigation,first,the risk probability is calculated for the project without anomalous change during the construction,with anomalous change but without remedial measures,and with anomalous change as well as remedial measures. Based on the probability calculation in the three above-mentioned cases,a calculation formula of full-probability method of abnormal project time is established. Then,by using the Monte Carlo thoughts,the Monte Carlo method calculation steps of the value-at-risk are presented based on Matlab, and the construction period change is described with the Beta distribution function. Finally,with an excavation engineering of a subway station as an example,the value-atrisk during the excavation period and the supporting period is calculated. The results indicate that the full-probability method and the Monte Carlo method are both effective.

Simulation Model of Sound Field in Street Space Caused by Noise Transmitted from Bordering Large Workshop Buildings

Zhang Hong-hu Zheng Wei

2012, 40(6):  145-151. 

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In order to control the propagation of air-borne noise from the interior of large workshop buildings to their neighboring streets through the envelop enclosure,the sound field in the street space caused by the noise should be predicted in the design stage of buildings,which helps to determine the measures of sound insulation and noise reduction. In this paper,by considering the features of the related sound field and by synthetically employing the classical room sound field theory,the image source method and the acoustical radiosity method,a simulation model is established to calculate the contribution of the noise inside the workshop building to the sound field in the street space. The core of the model lies in the calculation by discretizing the boundary of the sound field and in the reasonable simplification of the directionality of sound reflection and sound transmission,which makes the model effective in dealing with the sound field with complex space geometry and nonuniform acoustical property distribution.

Investigation into Functional Linkage Between Guangzhou and Foshan Represented by Subway Passengers

Zhao Miao-xi Wang Shi-fu Zhang Xiao-xing

2012, 40(6):  152-158. 

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This paper aims to reveal the functional linkage between Guangzhou and Foshan by analyzing the multiplace-information of subway passengers. In the investigation,the spatial information about the location stations and the household registration locations of the respondents is obtained,and its position offsets to respondents' basic behavior places for residence,work and leisure are analyzed. Then,the spatial interaction process of the functional activities of the respondents is deeply explored,and the spatial flow characteristics of residents' activities across the city during the Guangzhou-Foshan integration are discussed. The results show that the residents in Foshan are more dependent on the subway transfer stations and their spatial interaction for leisure is deeper than that for residence and work; and that the spatial effect of the Guangzhou-Foshan subway is imbalanced in the process of space restructure,for instance,Guangzhou is more attractive for subway passengers in terms of leisure while Foshan is more likely to be a residential city.