Table of Content

01 February 2010, Volume 30 Issue 2

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Network and communications

customR2: A hybrid push/pull scheduling method with network coding in P2P live streaming systems

2010, 30(2):  285-288. 

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Compared with the traditional pullbased scheduling methods in P2P live streaming systems, the random push scheme with random network coding, named R2, has a lot of advantages such as improving video quality of service, reducing overload of streaming servers and enhancing the resilience to nodes dynamics. However, the random push strategy in R2 is prone to producing a large amount of redundant coded blocks, thus wasting some precious network bandwidth. In this paper, a novel hybrid push/pull scheme with network coding, customR2, was proposed. When one downstreaming node received the most of coded blocks of one segment actively pushed from its upstreaming seeds, it would notify its seeds to stop push operations and start pull operations for the remaining coded blocks, to reduce the quantity of redundant blocks. By the simulations, the comparison between customR2 and R2 was conducted with respect to playback delay, streaming rate and network size. The results show that customR2 outperforms R2 in terms of redundancy ratio of coded blocks and playback quality.

Improved equal AQM based on CHOKe hits

2010, 30(2):  289-291. 

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Fair allocation of bandwidth is always a hot research issue of networks. Under different level of network congestion, New-XCHOKe calculated the number of packets picked from queue self-adaptively, and then compared them. New-XCHOKe identified non-adaptive flows by the CHOKe hits, and punished the non-adaptive flows by dropping their packets first to ensure the fairness of bandwidth allocation between different flows. The simulation results about New-XCHOKe and other main schemes by using NS-2 show that New-XCHOKe performs better than XCHOKe and CHOKe in punishing non-adaptive flows and allocating bandwidth fairly.

Optimization method for irregular LDPC codes in AWGN channel

2010, 30(2):  292-294. 

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A method to optimize irregular Low-Density-Parity-Check (LDPC) codes was proposed. The area gap between the EXIT curves of variable-node decoder and check-nodes decoder of a LDPC code reflects a rate loss compared to Shannon limit, a function F which computed the area gap was designed to evaluate the performance of the irregular LDPC codes. The lower the value F is, the smaller the gap between the convergence threshold and the Shannon limit is. Simulation shows that the performance of irregular LDPC codes will be improved by designing variable-node decoder and check-nodes decoder appropriately and reducing F.

Improved routing algorithm with least channel handoff

2010, 30(2):  295-298. 

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How to improve the performance of the wireless Ad Hoc network by utilizing the spectrum resources efficiently based on multi-channel has become a hot research topic in recent years. In this paper, an On-Least Channel Handoff-DSDV (OLCH-DSDV) routing algorithm was proposed, which was based on the traditional DSDV protocol to reduce the channel handoff in the network. This algorithm used a channel allocation strategy with minimum channel handoff，so as to cut down the handoff delay. Thus it could reduce the average delay of the network while improving the system throughput. This routing algorithm requires the source node to select the best route with the minimum handoff channel according to the channel information maintained by itself.

Clustering scheme based on simulated annealing algorithm in wireless sensor network

2010, 30(2):  299-302. 

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Targeting at the problem of Energy Hotspot caused by inter-cluster disadvantages of disequilibrium energy consumption load in Wireless Sensor Network (WSN), a clustering scheme of balanced energy load was proposed in the situation of randomly distributed nodes. The nodes whose energy was higher than the average energy of the network became the first candidate heads. Then the candidate heads competed to be clustering head according to their residual energy, connectivity, as well as the total time of being ever clustering head. The general node selected a cluster to join based on signal strength received from the clusters, and in accordance with the idea of simulated annealing algorithm, dynamically adjusted the members in each cluster, until each cluster approximated a balanced state of energy consumption. Simulation results show that the new scheme can obtain more balanced energy load clusters and longer life time than those based on uniform distribution assumption.

Efficient PAPR reduction for OFDM system based on optimized power allocation

Jing-Lian Huang

2010, 30(2):  303-305. 

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To solve the problem of high Peak-to-Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) systems, an efficient PAPR reduction scheme called OPAR was proposed based on optimized power allocation. This paper also analyzed the relationship between power efficiency of power amplifier and PAPR, and deduced the closed form formulation of power allocation between superimposing pilot signal and data signal. OPAR could allocate optimized power quickly with the given sub-carrier number and probability threshold of PAPR. Simulation results and comparison with the existing schemes demonstrate that the proposed OPAR scheme can obtain better performance in PAPR reduction.

Paralleled packet classification based on network processor

2010, 30(2):  306-308. 

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There are a large number of rules in large networks. This feature leads to overlong and sparse bit vectors of BV algorithm, which requires a large amount of storage resources and too many read cycles in network processor. An improved method, Tuple-BV algorithm, was put forward, which combined tuple space partition with the BV algorithm to reduce the length of bit vector and take advantage of parallel processing mechanism and hardware acceleration units in network processor. The improved algorithm shortens the length of bit vector and reduces storage space. The experiments prove that Tuple-BV algorithm is better than BV algorithm in terms of maximum delay and average delay when the number of rules is over one thousand.

TCP Vegas-P: Enhanced TCP Vegas congestion control algorithm based on congestion status differentiation over wireless heterogeneous network

2010, 30(2):  309-311. 

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In wireless network, channel interference and noise cause significant performance degradation of TCP. In order to solve the problems existing in the application of TCP Vegas, based on TCP New Vegas algorithm, combining the advantages of TCP Vegas A+ algorithm, an improved algorithm named TCP Vegas-P was proposed. It was improved to solve the premature end of the slow start phase and congestion avoidance in the reverse link congestion resulting in the throughput decline, and the fairness deterioration when it was accompanied by NewReno. The simulation results show that the improved algorithm in the wireless network can better estimate Round-Trip Time (RTT), and resolve the problems about Vegas, and can be well applied to wireless network environment.

Design and implementation of communication platform over WLAN based on SIP protocol

2010, 30(2):  312-315. 

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How to combine Session Initiation Protocol (SIP) with current communication system well so as to provide secure telecommunication services has become a hot current issue. Security issue is always the major barrier to employing Voice over Internet Protocol (VoIP) technology by enterprise. This paper presented a solution named VoWLAN for voice business over Wireless Local Area Network (WLAN) on the basis of SIP server and VoIP gateway which deploys various voice services. Virtual Private Network (VPN), data encryption, VLAN and firewall technique achieved good quality and safety enterprise VoIP platform were implemented, and the design and implementation procedure of the whole system were described.

Network planning model for 3G network based on 3D ray tracing technology

2010, 30(2):  316-318. 

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According to the requirements of 3G network planning, based on ray tracing theory, a method for predicting the strength of wave propagating was proposed. In this paper, it designed and built the 3D database based on GIS to provide the data for prediction, and used the bounding box and octree technologies to accelerate the algorithm. Finally, the result was displayed in 3D visualization. The simulation results show that the method can provide support data for 3G network planning sufficiently, and the visualization effect is good.

Adaptive sampling algorithm of network round-trip time

2010, 30(2):  319-322. 

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Round-Trip Time (RTT) is an important performance metric of IP network which reflects network paths workload characteristics. To overcome the ignorance of network performance variation characteristics of the equal-interval sampling algorithm, the paper presented an adaptive algorithm based on estimation method, which determined sampling time by the degree of delay variation. The verification shows that the method not only effectively tracks delay change but also reduces sampling time very well.

Localization algorithm based on DV-HOP for wireless sensor networks

2010, 30(2):  323-326. 

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In the wireless sensor networks, node localization is one of the key technologies. The authors theoretically analyzed DV-HOP algorithm and pointed out the main reason for the error. Then, an improved algorithm was brought out to use correction value as the estimated distance between anchor nodes and unknown nodes. This value was composed of the correction of the multi-hop and anchor nodes average distance error. Meanwhile, Total Least Squares (TLS) was applied to node localization to enhance the localization accuracy. Choosing Matlab as the emulator, it is proved that the localization accuracy of the improved algorithm is better than those of the original algorithm and some existing improved algorithms.

Variable random neighbor selection algorithm in live peer-to-peer network based on capacity factor

2010, 30(2):  327-329. 

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Based on the analysis of the algorithms of fixed random neighbor selection, a new variable random neighbor selection algorithm adaptable to hybrid P2P in live multimedia streaming networks was presented. The new algorithm measured fitness degree of node with its capacity factor. Different types of nodes have different maximum neighbors. Simulations show that the new algorithm can reduce the transmission delay and improve the performance of network system.

Effective selection algorithm of initial quantization parameters

2010, 30(2):  330-332. 

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Rate control is one of the most important mechanisms affecting digital video quality in network environments. As for the problem for low-quality and fluctuation of video images in JVT-G012 algorithm, caused by unreasonable choice of I-frame quantization parameter, this paper put forward a selection algorithm of I-frame quantization parameter, based on the R-Q model. Firstly, R-Q model of I-frame was got by curve fitting; secondly, the information of encoded frames was used to update I-frame weight relative to P-frame, and a reasonable target-bit was allocated for I-frame; finally, I-frame quantization parameter was calculated under the target-bit by R-Q model. Simulation results show that compared to the H.264/AVC standard algorithm, the improved algorithm accurately controls the bit-rate while improving the average PSNR of testing sequences, and makes the quality of video images more stable and smooth.

Improvement of AODV routing protocol in mobile Ad Hoc network

2010, 30(2):  333-336. 

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In this paper, the authors analyzed the AODV routing protocol and proposed AODV-BR routing protocol to improve the route maintenance in AODV by finding a backup route as to fix the weak link. The theoretical analysis and simulation results prove that this protocol can reduce connection failures and the packet loss rate.

Graphics and image processing

Efficient fractal image compression based on pixels distribution and triangular segmentation

2010, 30(2):  337-340. 

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The baseline fractal image compression algorithm requires a great deal of time to complete the encoding process. In order to solve this problem, an efficient fractal image compression based on pixels distribution and triangular segmentation was proposed in this paper. Exploiting the characteristics of centroid uniqueness and centriod position invariance in discrete particulate system, the matching between range blocks and domain blocks was implemented. In addition, dividing original image into isosceles right triangles segmentation could reduce the number of domain blocks, and raise the efficiency of fractal coding. Experimental results show that the proposed algorithm can produce reconstructed images with good quality and require one third time of the baseline encoding algorithm.

Blind image super-resolution restoration based on joint interpolation-restoration scheme

2010, 30(2):  341-343. 

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The primary motivation for developing the blind algorithm is due to the observation that most existing Super-Resolution (SR) methods assume the point spread function are known in advance, which may not be true in many real-world applications. In view of this, this paper presented a novel blind SR algorithm to enhance image resolution without knowledge of the point spread function. The authors formulated the SR problem into a new framework of joint interpolation-restoration scheme. The main contribution of this method was the development of multi-channel blind restoration to estimate the unknown point spread function, and its integration into the SR scheme to render High-Resolution (HR) images. The blurs were identified iteratively with the utilization of inter-frame blur similarity. Experimental results show that the new algorithm is effective in performing blind SR image reconstruction.

Image mosaic techniques in catching panorama image of hole wall

2010, 30(2):  344-347. 

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Using borehole digital camera technique to obtain the realistic panorama image of the hole wall has become one of the major ways to conduct geological analysis in geological survey. The existing methods of getting panorama image have such shortcomings as high cost of the equipment, unsatisfactory result of image splicing, etc. In this paper, a new method of acquiring the realistic panorama image of hole wall was proposed. By controlling the well depth and projecting the 360-degree cylindrical space of hole wall under the well onto plane, the authors could get the sequence ring images of hole wall, then unfolded the images and preprocessed them through median filtering algorithm, found out the overlapping parts of the image by the difference image matching principle, and blended them using Bezier curves approximation algorithm to achieve a smooth transition between images. Practical application on geological survey shows that the image mosaic technique presented in this paper is simple, flexible, efficient, and can provide ideal result of the panorama images of the hole wall.

Point cloud simplification with boundary points reservation

2010, 30(2):  348-350. 

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A non-uniform simplification approach with boundary points reservation was proposed concerning the boundary points loss caused by most point cloud simplification algorithms. First, kd-tree was used to represent the spatial topology relationship of the scattered point cloud and to calculate the k-nearest neighbors for each data point. Then an improved algorithm for boundary points detection of point cloud was presented to solve the low efficiency when the current algorithms extract boundary according to uniform distribution of point cloud. Consequently, all the resulted boundary points were reserved, while the non-boundary points were reserved for final non-uniform simplification according to the surface variation and their nearest neighbors. The experimental result shows that the proposed simplification approach has high accuracy and low space complexity, and can reserve the boundary points.

Colorization method with optional number of cluster and histogram matching

2010, 30(2):  351-353. 

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With regard to the low speed, unsatisfactory results and high manual intervention of color-transfer colorization algorithm, a new colorization algorithm was introduced. Firstly the problem of clustering number selection was resolved during image clustering, then object image and source image were segmented respectively using clustering algorithms. After that, histogram matching algorithm was adopted for object block images. To achieve local images colorization, the color was transferred from source block images to object block images. Finally, colorized block images were merged. The experimental results show that the algorithm is better than the previous in terms of speed, quality and automation of colorization.

Color image segmentation algorithm based on K-means clustering and region merging

2010, 30(2):  354-358. 

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This paper proposed a novel algorithm of color image segmentation, based on clustering and region merging. First, an image was smoothed while preserving the boundaries by mean shift algorithm. Second, the initial segmented regions were obtained using K-means clustering algorithm in the feature space. Finally, the initial regions were merged to form the final segmentation result by a new region merging strategy. The simulation results show that color image segmentation results of the proposed approach are well consistent with human perception.

Corner relocation based on density gradient direction

2010, 30(2):  359-361. 

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As a result of the impact of external factors, corners detected by corner detection algorithm may be offset. Based on the analysis of this phenomenon, this paper proposed a new algorithm for corner relocation. Firstly, through calculating the second-order template value for every corner, the fuzzy corner relocation was carried out; secondly, the density gradient direction of pixel was introduced. Comparing the density gradient directions of the corners and the neighborhood pixels of the corners, the wrong corners were determined precisely and all candidates were found; finally, according to the relationship between the corner and the candidate pixels, new corner was found. Experimental results show that the algorithm can accurately relocate the wrong corners.

Novel geodesic distance Fourier shape descriptor

2010, 30(2):  362-363. 

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On the basis of conventional Fourier shape descriptors for image retrieval, the paper introduced a novel shape-based geodesic distance Fourier Descriptor (FD), and the proposed FD was tested on the standard shape database MPEG-7. The experimental results show that it outperforms conventional Fourier shape descriptors.

Hybrid algorithm for low illumination video enhancement

2010, 30(2):  364-366. 

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In order to improve the visual effect of low illumination video, a hybrid algorithm was proposed, which included the Logarithmic Image Processing (LIP)-based enhancement algorithm and the improved bi-direction balancing algorithm. The number of processing frames was reduced by using the inter-frame cross-correlation to improve the processing speed. Experimental results show that the proposed algorithm can obtain more satisfactory results.

Infrared weak target segmentation under complicated background based on mountain clustering

2010, 30(2):  367-369. 

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With the analysis of the features of infrared image, an infrared weak target segmentation method based on mountain clustering was presented. First, the original image was projected to x and y coordination to construct dataset and used as sample to cluster. Then based on the datasets, the improved mountain clustering algorithm was implemented, and the clustering centers were employed as the seeds in region growth, and at last the final segmentation was acquired. Experimental results show that the proposed method outperforms the traditional approach and it can provide satisfactory segmentation result.

Moving shadows removal algorithm based on photometric properties and multi-gradient analysis

2010, 30(2):  370-373. 

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An algorithm based on photometric properties and multi-gradient analysis was proposed to remove the moving shadows. After detecting moving objects accurately, firstly, photometric properties and connected components analysis were used to detect potential shadow regions; secondly, multi-gradient in potential shadow regions was compared with that in the background, and connected components analysis was adopted in order to remove the shadow; lastly, edge removal was imposed to further remove penumbra, and morphological algorithm was used to improve the performance. Compared to the conventional method, the experimental results validate that the algorithm has a high detection rate and a high recognition rate.

Computer software

Research on scenario-event-driven simulation test script language for safety-critical software system

2010, 30(2):  374-379. 

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Script technique is an effective method to implement the automation of software testing. Using test script reduces the cost for the software test and improves the efficiency of software test. Test script language is the core of script technique, but the special test script language for safety-critical software test does not exist. Therefore based on the feature of the safety-critical software testing, the concept of safety-critical software simulation test script language (SED_SCS_STL) driven by scenario-event was presented in this paper. The design of the language and how the language was implemented on the safety-critical software simulation test platform was elaborated in detail. Finally the application of the language in the simulation and test of the train control center of CTCS-2 high speed railway control system was shown.

Multi-scale service composition approach based on statistics of service relationship

2010, 30(2):  380-384. 

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Based on statistical methods, Multi-Scale Web service Composition (MSWC) approach optimizes traditional workflow method in two aspects: automatic orchestration and complex service reuse. There are three steps in MSWC, service learning, coarse-grained service decomposition and fine-grained service decomposition. Service learning majors for calculating service probabilities, including logic and non-logic. Inspired by divide-and-conquer, services in the request list are divided into several groups in coarse-grained service decomposition, service logics are determined and service groups are mapped into existed atom and complex services in fine-grained service decomposition. And service composition is achieved by cascading all groups. For three steps are all automatic and existed complex services are used, MSWC is an automatic and complex service reuse approach for service composition.

Object-oriented three-layer modeling in MDA

2010, 30(2):  385-389. 

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Model drives the entire development process in the MDA (Model Driven Architecture) software development life cycle. Modeling, being a prerequisite for the conversion model, takes a key role in MDA and determines the result of MDA software development. Three kinds of MDA-based modeling techniques were presented: CIM (Computational Independent Model) modeling, PIM (Platform-Independent Model) modeling and PSM (Platform-Specific Model) modeling, in view of the research and analysis of current modeling techniques and different levels of system abstraction. This paper described the three abstract level modeling processes in detail and the conversion among them, thus wholly giving description of the MDA software development process and ultimately obtaining a MDA software development methodology.

Approach to service adaptation for constructing situational applications

Jing LI Wang-hu CHEN

2010, 30(2):  390-393. 

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To solve the mismatch of connected services in situational applications, a semi-automatic service adaptation approach was proposed. Service messages were described by tree grammar and operations for service adaptation were defined based on tree automata algebra. The completion of the set of service adaptation operations was also analyzed. And then, the approach to service adaptation for constructing situational applications was proposed and applied to building situational applications with a scenario of bioinformatics experiments. The results show that the adaptation based on the proposed approach is just-in-time, adaptive to the heterogeneity of services and of no need for hard-coding.

Study of VO process based on migrating workflow system in VBE

qian deFu

2010, 30(2):  394-397. 

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According to the comprehension of Virtual Organization (VO) business process in Virtual Breeding Environment (VBE) and the normal infrastructure of migrating workflow, a model of migrating workflow system with VBE as its migrating domain was proposed in this paper. A service discovery mechanism was given combining the autonomous management of organization and the inviting public bidding through service market. Subsequently, the VO management process based on migrating workflow was depicted. The VO complementation in VBE with the proposed model is an excellent method with quick creation, low cost of communication, high effectiveness and wide range of application.

Research and implementation of embedded Java reflection mechanism

2010, 30(2):  398-401. 

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Java reflection is an important technology, which can improve software system flexibility and is a key feature for Java to be regarded as dynamic language. Though CLDC specification does not support reflection, it is still required in embedded area based on Java technology. Sun Microsystems released a reference implementation of embedded Java technology according to CLDC specification. The authors described the reflection design principle in detail by analyzing related data structure and mechanism of KVM, as well as it presented a method to extend reflection for KVM. The method is proved feasible by test.

Research on ontology-based model for supporting software knowledge sharing

2010, 30(2):  402-405. 

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For supporting Software Development Knowledge (SDK) sharing among members in the distributed team, SDK and its relationship must be analyzed and defined. In the paper, the formalized representation of SDK was shown based on SDKs content, characteristics and relationship. Then, the SDK ontology and its rules were described. The ontology database in which SDK ontology and its rules were created, transformed and implemented by using protégé, SPARQL and Jena, was built in order to support SDK sharing.

Research on semantic-based component composition approach

2010, 30(2):  406-410. 

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In component composition-based system, the automatic composition oriented to high-level requirements is still confronted with many difficulties. Nevertheless, to support the automatic component composition based on semantic information to specific types of application in restricted context is still feasible. An approach that used keywords to describe semantic information, modeled the components and process of querying and applied a planner to search for the component sequence was proposed. The method has been used in a data query system for satellites testing and obtains favorable result.

Information extraction based on semantic role and concept graph

2010, 30(2):  411-414. 

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Because the traditional information extraction approaches are lack of semantic information, the accuracy is not high in extraction. In order to solve the problem, this article proposed a novel method of information extraction based on semantic role and concept graph. On one hand, the process transformed the shallow semantic information into concept graphs, and accurately described the main meaning of sentences. On the other hand, the calculator computed the similarity of concept graphs so as to distinguish the different domains of information. Meanwhile, the mapping rules would be got by using semantic role for improving the quality of extraction. The experimental results show that this method of information extraction is feasible and effective.

Research and implementation of automatic question answering system based on ontology

2010, 30(2):  415-418. 

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An approach to constructing course knowledge base with ontology was proposed to overcome the deficiency of knowledge representation in the existing automatic question answering system. Questions were classified according to their traits. The intention of a question was transformed into the query of basic elements in ontology, and was implemented via Jena statements, and the answer was extracted finally. The proposed approach is proved by experiments.

Improved R*-tree spatial index

WU QinYang

2010, 30(2):  419-422. 

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R*-tree spatial index manages nodes based on the idea of partial adjustment, but lacks time and efficiency. In order to overcome the shortages of R*-tree, the paper proposed a new storage structure, and the algorithms of insertion, overflow and split for the new storage structure. The merits of the storage structure were analyzed. Experiments verify the new storage structure is more efficient than R*-tree.

Novel tree cluster and classification approach based on least closed tree

2010, 30(2):  423-426. 

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A tree clustering and classification algorithm was proposed based on least closed tree, which effectively solved the problem that the clustering and classification can not be completed when data amount is very large in practical application. Least closed tree was regarded as the candidate cluster and classification features. The dynamic threshold was used for similarity cluster to make tree cluster operation rapid and accurate. Meanwhile the concept of tree classification rule grade was proposed and applied in tree classification algorithm, so that the unknown tree structure could be predicted promptly. Experimental results show that the method has higher speed and efficiency than that of other similar ones especially with large number of tree nodes.

Scheduling analysis of linear approximate response time in hard real-time system

2010, 30(2):  427-429. 

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By the approaches of being linearly close to the workload of tasks in hard real-time system, the closer response time upper bound can be used to decrease the running time. At the same time, it is linear in time of complexity for the upper bound in the sufficient schedulable tests of task sets. In interactive system design tools, system optimization via search, and admission of new tasks into dynamic systems, this new linear upper bound can considerably improve the efficiency of test. Further, the scheduling model has wide application range because it does not have the limits of deadline and jitter. The pertinent experiments show that the method of utilizing the approximate upper time improves the efficiency of accurate test of the scheduling.

Pattern recognition

Human facial wrinkles recognition based on Gabor filter and BP neural network

2010, 30(2):  430-432. 

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For the impact of strong noises such as splashes and pores, human facial wrinkles recognition was severely disrupted, especially for the recognition of facial fine texture. This paper proposed a recognition method based on Gabor filter and BP neural network to recognize facial wrinkles. Firstly, BP neural network was trained to identify the existence of texture by Gabor filtering results and then whether the wrinkles exist or not was judged. One wrinkle sample database was created from a number of face photos with different ages, and the database had been used to train BP neural network. In this paper, wrinkled and non-wrinkled pictures were selected, and then Gabor filter bank was used to calculate their frequency spectrum as the training samples. Then, the trained neural network could be used to recognize human facial wrinkles. A large number of test results show that the algorithm can eliminate or reduce interference of splashes and pores and over 85% recognition accuracy can be got.

Road extraction from remote sensing images combining region growing with level set

2010, 30(2):  433-436. 

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A color region growing algorithm based on PCA (Principal Component Analysis) was proposed. Level set method was employed to extract urban roads from high-resolution remote sensing images. Firstly, the region growing algorithm was applied to the preliminary road segmentation, and then the roughly obtained road region was used to construct the initial level set function, which then evolved stably according to a level set evolution equation without re-initialization. Finally, a regularizing local edge algorithm based on level set without re-initialization was presented, and utilized to regularize the local erroneous road curve due to obstacles. Experimental results show that the method is efficient and practical for extracting complete roads from high-resolution remote sensing images, with less manual intervention and stronger anti-noise ability.

Overprint error detection algorithm based on mathematical morphology

2010, 30(2):  437-440. 

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In order to get the precise Overprint error, a new Algorithm of the detection based on mathematical morphology is proposed. Firstly, the method of edge detection based on mathematical morphology is adopted to extract the edges of the mark .Then the sub-pixel position of the target center is obtained using the least –mean square circle fitting algorithm, and lastly, the result is worked out with the formula using the data obtained above. The experimental and factual testing results show that the proposed algorithm can filter the noise successfully and can meet the demands of high-quality and real-time of overprint. error detection

Fast high-precision reliable image matching algorithm based on shape

2010, 30(2):  441-444. 

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A fast and high-precision reliable shape-based matching algorithm is proposed to improve industrial detection precision and speed of image matching in this paper. First, the definition of image matching similarity measure is proposed. Then, image search matching strategy was adopted from coarse to fine. Specific procedures are given. First, the template is generated by selecting the region of interest in the reference image. Then, it is the process of filtering the template and the search image using canny operator, and computing the direction vectors of their edges. The image pyramids are constructed for the filtered template and the filtered search image on this basis. The image matching is carried on at the highest level of the image pyramid under the similarity measures. After the potential matches have been identified, they are tracked through the resolution hierarchy in successive until they are found at the lowest level of the image pyramid. Finally, the subpixel-precision pose parameters are achieved through the least-squares adjustment. Experiments demonstrate that the algorithm meets the actual industrial demand. It is robust to the occlusion, the clutter, the nonlinear illumination, the defocused, the low contrast, the global contrast change, the local contrast change, and so on. The precision of the image matching is less than 0.1 pixel. The speed of the image matching is less than 160ms for 512pixel*512pixel image, less than 270ms for 1024pixel*1024pixel image, less than 420ms for 2048pixel*2048pixel image.

Wavelet packet and hidden Markov model for off-line handwritten signature recognition

2010, 30(2):  445-448. 

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The paper proposed a way of off-line handwritten signature recognition based on wavelet packet and Hidden Markov Model (HMM). Wavelet packet was used to extract the features for the whole normalized signature image; the distribution of the wavelet packet coefficients could be approximated by mixture Gaussian model, and the state transfer model of HMM was adopted to describe the relevancy and dependency of each channel in the mixture Gaussian model. The data preprocessing is simple, and the feature extraction is complete and reversible. This method avoided complex segmentation and illuminated the decomposed statistical characteristics of the signature image. The experimental results show that the algorithm has better anti-noise ability, robustness and the recognition rate is higher.

Text extraction based on clustering colors at sensible points and clustering text-lines for text-selection

2010, 30(2):  449-452. 

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Since the existing text extraction methods can not adapt to the variation of complex background and shape, a new method was brought forward. It was founded on two-level color clustering of sensible points and text-line clustering. Because human vision perception is more sensitive to great change of colors, the new method only selected the main colors at sensible points to cluster. The strategy could solve the problems of the existing methods based on threshold and clustering which were greatly influenced by the variation in colors of complex background. And then, the text-lines were selected according to the fact that texts always align with each other in a same text-line. That course can eliminate the influence of variation in shape and size of characters. Experimental results indicate that, the new method has good adaptability to complex change of background, and texts with different size and shape.

Artificial intelligence

Inventory routing problem and its recent development: Review

2010, 30(2):  453-457. 

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Based on the analysis of the literature related to Inventory Routing Problem (IRP), this paper provided a general definition of IRP, and classified it. Its traits and attributes were elaborated in terms of topologic structure, plan time, guest request, deliverability, resource plot and distribution model. The main change of literature published after 2000 was analyzed. Finally, the paper compared the development between home and abroad. The conclusion marks that the further work should expand the IRP itself since its resolution method has been investigated sufficiently.

Constrained multiple traveling salesman problem based on self-organizing optimization algorithm

2010, 30(2):  458-460. 

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The Multiple Traveling Salesman Problem (MTSP) is an extension of the traveling salesman problem (TSP). MTSP is a classical combinatorial optimization problem with more complexity and applicability. The MTSP with the up-limit of the cities to be visited for each salesman was studied and the self-organizing algorithm (SOA) was introduced to solve the problem. The MTSP was transformed into a TSP by introducing virtual cities and the local fitness of virtual city was defined to deal with the relevant constraints. The computational results with a number of benchmark problems show that SOA can be effectively applied in solving the proposed MTSP with superior performance.

Research and implementation of group path generation based on particle swarm optimization

2010, 30(2):  461-464. 

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Simulating group behavior is always a hot issue in computer graphics. The difficulty is how to show the independence of individual and the wholeness of group. This paper analyzed group behavior, and then used the group intelligence of Particle swarm optimization (PSO) into the path generation. It not only used the initial idea of PSO, but also modified PSO according to the different group behavior. Then it created a new method to generate group path quickly.

Ensemble learning algorithm on attribute combination

2010, 30(2):  465-468. 

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Concerning the classification of samples being composed of digital attributes, an ensemble learning algorithm based on linear combination of samples attributes was proposed. It constructed classifiers based on combined attributes instead of single attribute by traditional AdaBoost algorithm. The general construction idea for attribute combination coefficients was put forward. In accordance with the idea, several concrete construction methods for combination coefficients were given and analyzed to be scientific and reasonable. The experimental results on UCI machine learning dataset illustrate that the ensemble learning algorithm based on attribute combination is effective and outperforms AdaBoost algorithm.

Artificial fish swarm algorithm for multiple knapsack problem

2010, 30(2):  469-471. 

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The Multiple Knapsack Problem (MKP) is a NP-hard combinatorial optimization problem in many real-word applications. An algorithm with the behaviors of preying, following and swarming of artificial fish for searching optimal solution was proposed in this paper. With regard to the problem that infeasible solutions are largely produced in the process of initializing individuals and implementing the behaviors of artificial fish due to the multiple constraints, which undermines the algorithm performance, an adjusting operator based on heuristic rule was designed to ensure all the individuals in the feasible solution areas. Computational results show that the algorithm can quickly find optimal solution. The proposed algorithm can also be applied to other constrained combinatorial optimization problems.

New modified particle swarm optimization on basis of two latest generations

2010, 30(2):  472-475. 

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A modified Particle Swarm Optimization (PSO) on the basis of the two latest generations was proposed to solve the problem that no satisfactory results can be reached during later period of PSO, especially in high-dimensional search space. A new part was added to the velocity of replacement formula，suggesting that the particle comprehensively utilized the information from the previous two acts to instruct its next step. Primarily based on the record of recent changes of the current particle in the two latest generations, the central location of the previous two generations of the particle was calculated，the role of which was to point out the current global optimal position. The paper，at the same time, discussed deeply a new learning factor and their impact on the new modified algorithm. The experimental simulation results show that global searching ability, convergence rate, accuracy and stability of the new algorithm have been improved significantly.

Euclidean distance based method forunclassifiable region of support vector machine

2010, 30(2):  476-478. 

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To overcome the disadvantages of Unclassifiable Region (UR) in conventional Multi-classification Support Vector Machine (MSVM), and increase the classification capacity and generalization ability of MSVM, Euclidean Distance Method (EDM) was presented. EDM computed the distances between the sample in UR and every class center directly, and then selected the class with the least Euclidean distance for the sample. The experimental results on benchmark datasets show that EDM eliminates the UR in conventional MSVM and improves the classification capacity and generalization ability of MSVM effectively.

Hardware/software partitioning algorithm for embedded systems based on immune particle swarm optimization

2010, 30(2):  479-481. 

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Hardware/software partitioning is one of the most important issues of the design of embedded systems. This paper described an approach based on immune particle swarm optimization algorithm. Affinity, clone copy operator, clone hyper-mutation operator and clone selection operator were redefined. The experimental results show that the algorithm can not only escape from local extreme but also improve the precision of the optimal solution.

Airport taxi scheduling optimization strategy based on genetic algorithm

2010, 30(2):  482-485. 

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An airport taxi scheduling optimization strategy based on genetic algorithm was represented, which firstly determined the sequence of all the aircraft at each taxi intersection, and then solved the detailed scheduling. The optimization was found after some iterations. This strategy effectively enhances the solving efficiency in comparison with the Mixed Integer Linear Programming (MILP) model.

Forecasting method for water quality time series of few and abnormal data

2010, 30(2):  486-489. 

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According to the characteristics of small samples and sudden change of some According to the characteristics of small samples and sudden change of some sections in Three Gorges, the ELS-SVM water quality prediction model for Three Gorges was proposed, which consisted of Equal Level Pretreatment Model (ELPM) and Least Squares Support Vector Machines (LS-SVM). ELPM was brought forward to preprocess raw time series data to enhance the smoothness, and Simulated Annealing (SA) algorithm was used for choosing the optimal parameters of LS-SVM. The experimental results indicate that, compared to the typical forecasting models in limited samples prediction, the ELS-SVM forecasting model is superior to the others in water quality parameter prediction of Three Gorges.

Supply capability of large-scale supply network chain based on vendor-selection

2010, 30(2):  490-494. 

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Under the circumstance that the supply falls behind the demand, in order to satisfy market demand as much as possible, the core enterprises need vendor-selection in the supply chain to achieve maximum supplying capacity for the entire supply chain network. In order to solve the large-scale portfolio alternatives and the difficult calculation effectively, a nested hybrid genetic algorithm was used to optimize this issue. Meanwhile a new algorithm was presented for solving large-scale network maximum flow. The simulation results show that this method draws the right vendor-selection, and figures out the maximum supplying capacity for the network.

Empirical research on customer segmentation of securities based on clustering

2010, 30(2):  495-498. 

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This paper proposed a multidimensional customer segmentation model applied in securities industry, and carried out an empirical research in real customer data from a domestic famous security company by the clustering analysis of data mining. Finally, some marketing strategies were put forward in correspondence with different customers of different traits and preferences.

Information security

Survey on secure network coding

2010, 30(2):  499-505. 

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The recent advance in secure network coding techniques was reviewed. Firstly, the main idea of network coding was introduced. Then a number of secure network coding protocols were demonstrated to contact different adversaries in communication networks and the design of secure network coding schemes integrated with the characteristics of network coding was highlighted. Furthermore, a brief overview of the relationships among secure network coding, cost criterion and network capacity were presented. Finally, the theory and application prospects for secure network coding were given and analyzed. Considering the intrinsic properties of network coding, to devise simple and efficient secure network coding schemes is an important tendency.

Protocol for privacy-preserving set intersection

2010, 30(2):  506-509. 

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Privacy preserving set intersection was analyzed in the secure multi-party computation. Based on semi-honest model and scalar product protocol, a protocol of the bipartite set intersection was constructed, which complexity is O(ntp); another protocol of the tripartite set intersection needs O(2ntp). Then the correctness of these protocols was illustrated and the complexity and security were analyzed precisely. The analysis shows that the new protocols are more efficient than current protocols. Finally, the application and deficiency of these protocols were also discussed.

On the security of certificateless signature scheme without pairing

2010, 30(2):  510-512. 

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Certificateless public key cryptology does not need certificates to verify the validity of public key, and overcomes the key escrow problem in ID-based public key cryptology. By analyzing the security of a certificateless signature scheme without pairing, it was pointed out that the scheme is insecure against a malicious Key Generating Centre (KGC) attack. Then, an improved scheme was proposed, whose security was based on the Discrete Logarithm Problem (DLP).

Certificateless threshold multi-proxy multi-signature scheme

YANG Chang-Hai

2010, 30(2):  513-516. 

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This paper proposed a certificateless threshold multi-proxy multi-signature scheme by adopting certificateless cryptography, multi-proxy multi-signature and secret sharing scheme. In this scheme, original signers could cooperatively finish proxy-delegation process only when the number of original signers went up to threshold value, and proxy signers could cooperatively generate threshold multi-proxy multi-signature only when the number of proxy signers went up to threshold value. By analyzing the scheme, it is concluded that the scheme has the security properties which multi-proxy multi-signature and threshold signature need, such as resisting frame attack and conspiracy attack which is caused by inside members.

Fake verification analysis of SVD-based image watermarking

2010, 30(2):  517-520. 

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A fatal bug of a kind of Singular Value Decomposition (SVD)-based image watermarking was discovered in this paper. That is, using the same secret key which is produced in the embedding procedure, highly correlative watermark information can be extracted from other different images, even including non-watermarked images. This newly discovered bug was named as fake verification of watermark algorithm. At the same time, the definition and judging condition of fake verification were also presented. Then, the experimental results reveal that the watermark information is involved in the orthogonal matrix U,V after SVD. And the extracted watermark information is mainly involved in U,V, and the distribution of single value instead of exact single value. That is the reason why the SVD-based watermark algorithm has the bug of fake verification.

k-hop compound metric clustering algorithm based on trust in tactical Internet

2010, 30(2):  521-524. 

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Based on the analysis of the characteristics of Tactical Internet (TI), this paper presented a trust based k-hop compound metric clustering algorithm (TBKCM), which used the nodes administration level, trust level, residual energy, relative mobility, and identity jointly to select cluster heads, thus enhanced the network security and stability. As one hop cluster was extended into k hops, TBKCM improved the scalability of large scale TI significantly. This scheme introduced an on-demand cluster maintenance strategy in order to maintain network topology available and timely, at the same time, to reduce the cost of control. The simulation results show that, clusters created by using TBKCM approach retain modest and more uniform cluster size. The cluster head duration time increased compared with other clustering schemes and thus created much more stable clusters.

Mixed image fusion encryption based on pseudo-random points

2010, 30(2):  525-528. 

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Encryption is very important in image data transmission on Internet, but most of all encryption algorithms following the principle of dynamics of recession will be degraded into a cyclical algorithm, which leads to the leakage of image information and so on. Based on pseudo-random points, a mixed image fusion algorithm was presented. Firstly the image was divided into 8 × 8 small blocks, and then each block was transformed to create a pseudo-random sequence. The image block pixel values and their related pseudo-random sequence were fused and scrambled, and the image after EZW coding was scrambled again by chaotic sequence. Test results show that the algorithm has good security, and the algorithm is also relatively easy to achieve.

Comprehensive tolerance warning method of worm based on greedy algorithm

2010, 30(2):  529-531. 

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Because there are a lot of difficulties in predicting the network worm exactly, a tolerant warning method based on greedy algorithm was proposed. The method took the characteristic of the spreading of worm into account, adopted some tolerant measures for some less harmful worms. A special data structure of datagram was designed, by statistical analysis of these datagram in the server, and could judge the threshold whether the warning system should be started up. The experimental simulation and theoretical analysis show that the method is feasible to some extent.

Typical applications

Design and implementation of ontology-based knowledge base system for marine hydrocarbon geology

2010, 30(2):  532-536. 

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In order to efficiently apply and effectively spread the knowledge of marine hydrocarbon, in terms of the ontology for knowledge representation, a variety of documents were translated into standard TXT documents in which all the clauses were segmented into a set of words by marine-facies and relevant ones to extract ontology concepts from marine-facies geology. On the basis of B/S infrastructure, the knowledge system of marine hydrocarbon was successfully implemented, on which the marine-facies knowledge could be automatically acquired from a variety of documents. The maintainable function of the knowledge system for majority words and relevant words guarantees the accuracy of knowledge acquisition. The knowledge of marine hydrocarbon was retrieved quickly and shared widely. The knowledge system is proved to be reliable, efficient and practical.

DEM generation and accuracy analysis in Zhenjiang using InSAR

2010, 30(2):  537-539. 

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Interferometric Synthetic Aperture Radar (InSAR) is a new method for acquiring precise Digital Elevation Model (DEM). To obtain the high quality of the DEM generated by spaceborne InSAR, the accuracy and data structure of SRTM DEM were investigated. Then DEM was generated using ERS1/2 SAR images in Zhenjiang of China, and its accuracy was compared with that of SRTM3 DEM. The results show that the resolution of the DEM generated by spaceborne InSAR was correspondent with SRTM3 DEM. The surface features of the test zone in Zhenjiang were displayed perfectly. Moreover, there are about 5m system errors from spaceborne InSAR DEM and SRTM3 DEM. The causes of errors were analyzed in detail.

Airline flying conflict survey and extrication based on dynamic velocity modulation

2010, 30(2):  540-542. 

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A scheme for conflict resolution with dynamically changing the speeds of two or three aircrafts flying on the two air flows in the same flight height was proposed. The positions of the aircrafts and the distance between them were dynamically checked while the aircrafts entered the alert area, which was a circle plate around the intersection of the two air flows. The scheme computed the distance between the aircrafts and the intersection firstly. Then the coordinates were set up according to the distance computed on last step; therefore, the coordinates became the aircraft coordinates with small distance. The speeds were adjusted according to a set of partial differential equations and optimal control theory. The experimental results show that the scheme is safe.

Parallel computing method of data stream quantiles with GPU

2010, 30(2):  543-546. 

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The real-time, continuous and rapid arrival properties of data streams decide the real-time processing capability of data stream. Quantiles are commonly used for describing data stream with low dimension distribution. The research focused on mining powerful computing capacity and high memory bandwidth of Graphics Processing Unit (GPU) to compute data stream quantiles, and presented a GPU cooperated parallel processing model of data stream based on Computing Unified Device Architecture (CUDA) as well as parallel computing method of data stream quantiles which increased data stream processing bandwidth remarkably with precision no less than pure CPU algorithm.

Parallel rendering efficiency analysis of 3D graphics on PC cluster

2010, 30(2):  547-550. 

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In this paper, the efficiency of parallel 3D graphics rendering on general-purpose PC cluster was investigated. Three key factors affecting the efficiency of parallel rendering were analyzed, including network performance, algorithm complexity and parallel rendering mechanism. Parallel rendering simulations based on MPI and OpenGL were carried out on gigabit Ethernet PC cluster. The experimental results were analyzed and the advices for designing efficient parallel rendering system on PC cluster were given.

Traffic modeling and simulation of expressway weaving area based on cellular automata

2010, 30(2):  551-554. 

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Complicated traffic flow in the expressway weaving area can easily cause traffic congestion, which has become the traffic bottleneck. The micro simulation about expressway weaving area composed of an off ramp, an on ramp, a main line lane and an assistant road was made through modeling, based on Cellular Automata (CA) NS model, and was carried out by setting car-following rules and lane-changing rules. The simulation shows the optimal reference value of the length of weaving area and the effect on traffic flow parameters, such as flow, density and velocity, and the simulation model was verified by the calculation result of HCM empirical formula.

Design and development of H.264-based embedded network video server

2010, 30(2):  555-559. 

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This paper developed a network video server based on Freescale video processing chip IMX27 running on the Linux operating environment, and short connection was used to complete the interaction between the server and clients, which effectively saved system resources and reduced the CPU utilization of the sever. Moreover, in order to obtain high quality video images, the server adopted an adaptive de-interlacing algorithm based on the use of splicing and interpolation of static and moving picture respectively to realize de-interlacing of the video image, therefore the integrity of the video data was guaranteed and the video clarity was improved. In the end, an application case of the server was given, which achieved the desired designed goal.

Intelligent fire-fighting vehicle model based on embedded system

2010, 30(2):  560-563. 

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By taking advantage of ARM9-based embedded Linux system, an intelligent fire-fighting vehicle system was designed, which was of good performance of human-computer interaction for automatic detection, identification, location of fire sources, and automatic navigation and fire extinguishing after the arrival of the fire area. In this paper, the system was introduced throughout the overall system architecture as well as the composition of modules，the development of embedded system, the design of WLAN-based monitoring interface. The system can timely find and fight fires, to achieve disaster prevention and mitigation.

New mixing algorithm for network and telephone conference

2010, 30(2):  564-566. 

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Mixing treatment plays a pivotal role in Internet phone conference system. The core of mixing processing is how to resolve overflow and noise problems caused by the mixing. By analyzing the existing problems in mixing algorithm, an adaptive spectral method was proposed. Without overflowing, Fourier transform was applied to the speech signal. The noise power spectrum was removed from the noisy speech power spectrum, and then a more pure voice frequency spectrum was achieved. Fourier inverse transform was compatible with the mixing weights to make the sound quality clearer and more naturally smooth after mixing. It solves noise problems of mixing process and improves the quality of post-mixing to approximate the effect of real meeting. Therefore, it can be applied to multi-media conference system.

Speech automatic segmentation algorithm of audio publication with adaptive threshold adjustment

2010, 30(2):  567-570. 

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In order to achieve the automatic speech segmentation of audio publication, the system model with adaptive time threshold adjustment and similarity detection was established. The adaptive threshold adjustment algorithm was put forward to set the time threshold based on the prior knowledge of script. In order to improve the anti-interference and adaptive abilities, a new algorithm based on the similarity detection of speech units was provided. The test results show that the accuracy of segmentation is 100% when the system has no interference, but the accuracy of segmentation is 98.8% when two interference signals are added to each speech files on average. Practical application shows that the system can meet the automatic segmentation requirements.