Table of Content

01 January 2010, Volume 30 Issue 1

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Database technology

Revisit of B+-tree index in flash-based environment

2010, 30(1):  1-4. 

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The increment of flash memory devices provides opportunity for large flashbased applications, and hence flash based database has become one of the promising research areas. B+-tree is the most widely adopted index, which is a fundamental structure for DBMS. The performance of B+-tree stored on both flash chip simulator and SSD is both evaluated. The authors evaluated the basic IO features of SSD and compared it with the traditional hard disk, followed by the detailed testing result on the B+-tree. The results show that node size, buffer and data distribution have great effect on the performance of B+-tree. Due to the asymmetry of flash input and output speed, the optimal node size of query and insertion are different from each other. These testing results will be a meaningful guidance for both application and improvement of B+-tree.

Microbiology information service system based on object deputy database

2010, 30(1):  5-9. 

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A new approach for microbiology information management based on object deputy database was proposed. It used the object deputy model for data modeling. The common descriptive information of microbes was defined as the basic object. Microbial diversity and correlated information of microbes were modeled through deputy objects. A microbiology information service system based on our object deputy database was implemented. Advanced functions of the database could facilitate information management. Update propagation supports dynamic classification of data, object views could be used for schema evolution, and crossclass query provides efficient data retrieval. The experimental result shows that this approach outperforms the traditional ones.

Task classification of intervention rules mining and advances of three technologies

2010, 30(1):  10-14. 

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The main contributions of this paper include: (1) introducing the basic concepts and mining methods of intervention rule over subcomplex system; (2) proposing the classification criteria for the tasks of intervention rules mining; (3) surveying the advances on three special mining techniques for intervention rules, including disease state intervention, intervention discovery from data streams, and intervention mining from parallel event sequences;(4) discussing the challenges and future research of intervention rules mining.

Using Gini measures to evaluate and optimize structure of cluster’s nodes

2010, 30(1):  15-17. 

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Load balancing mechanism is an approach to improve the overall handling capacity of the cluster, but the unreasonable structure of the clusters tends to limit the efficiency of load balancing mechanism. Incoordination between the two limits the performance of system hardware and software. Through establishing the simulation system of load balancing and introducing Gini method, the paper analyzed the relationship between the structure of cluster’s nodes and its load balancing mechanism. Then a method was proposed to evaluate and optimize the cluster system. The method was verified by experiment, and direction for further research was pointed out.

Research on semantic description and retrieval of component database

2010, 30(1):  18-21. 

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The traditional methods of description and retrieval of component database cannot describe the semantic relation of components, obstructing their application. Therefore, a description model of components was founded by means of ontology, in order to carry out semantic extension of component retrieval. The method that works out the similarity value between function of component and requirement of users was presented. It helps users to quickly and precisely find the components in need.

Hybrid indexing of moving objects based on BX-tree

2010, 30(1):  22-24. 

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A SelfAdaptive BX-tree (SABX) was presented for indexing the current and future position of moving objects. Taking account of the different density of moving objects in reality, SABX-tree utilized the technology of temporal partitioning and spacefilling curves to calculate the objects’ position, then a supplemented Hash index was introduced to store and index the forest of BX-trees. Besides, the insertion，deletion, update methods and range query algorithm were developed for SABX-tree. Experimental results show that SABX-tree’s dynamic update and query performances outperform those of BX-tree and traditional TPRtree.

Approach for mining association rules based on rough set

2010, 30(1):  25-28. 

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In this paper a novel approach for mining association rules based on rough set theory was presented. It firstly used the rough set’s feature attributes reduction algorithm to reduce attributes, and then applied the improved Apriori algorithm to mine association rules based on the reduction decision table. The advantages of this method were that it reduced the number of the attributes by reducing the unimportant attributes,also reduced the number of candidate item sets and could produce the association rules by scanning decision table only once. The results of application and experiments show that this method is fast and effective.

Graphics and image processing

Application of multi-label image segmentation

2010, 30(1):  29-30. 

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A new approach of semiautomated image segmentation based on multi-label pixel was presented. First, a weighted graph of un-processing image was defined by Gaussian weighting function. Second, the pixels of different goal region were labeled differently in source image. An un-labeled pixel was randomly selected as the starting point. Then, random walking started from this location according to the defined weighted graph, calculating the probability from the start point to each pre-labeled pixels. A probability graph toward each unlabeled pixel was obtained, which represented all probabilities that each unlabeled pixel randomly reached each of pre-labeled pixels. The greatest probability was taken as its objective, therefore, a high-quality image segmentation could be obtained.

Source camera identification technique using large components of imaging sensor pattern noise

2010, 30(1):  31-35. 

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A new method for source camera identification was proposed based on using large components of imaging sensor pattern noise. Concerning the extraction and preprocessing of pattern noise, this paper discussed how the de-noising filter and the de-CFA interpolation operation could improve the quality of pattern noise. Afterwards, focus was made on why and how the use of large components of the sensor pattern noise could improve the performance of the correlation-based detector. The proposed method can not only separate the data obtained from two cameras well, but also greatly decrease the computational load for detection.

Theft detection based on omni-directional vision sensors

2010, 30(1):  36-40. 

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This paper designed a system about theft detection to realize smart video surveillance in public locations. Firstly, aiming at the problem of small visual field, Omni-Directional Vision Sensors (ODVS) which have 360 degree and nondeadangle view were used to capture panoramic images of scene. Secondly, by processing the input video at different frame rates, two backgrounds were constructed: one for short-term and the other for long-term. A special background was detected by comparing the current frame with the background. Meanwhile, moving objects and static background could also be distinguished. The stolen object would be detected as a special background. Experimental results show that the system is robust enough to detect the stolen objects effectively.

Motion vector recovery for inter-frame error concealment in H.264

2010, 30(1):  41-43. 

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Concerning the video quality decline caused by damaged macroblocks in video transmission, this paper modified the boundary matching algorithm by adopting the interlaced weighted double error concealment scheme, inducted the motion vector estimation selectively, and used 8×8 subblocks correlation error concealment mode when the boundary matching error of the predictive block was higher than a given threshold. Experimental results show that the proposed algorithm could averagely raise the PSNR about 1dB and correspondingly improve the decoded video quality effectively.

Enhancement technology for container X-ray images

2010, 30(1):  44-46. 

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Because of the characteristics of the container itself and the error of X-ray machine, the container X-ray images have lots of strong noise. In order to improve the region of interest and inhibit the region of uninterested in, an improved method based on contrast limited adaptive histogram equalization was introduced in the paper. Firstly，the X-ray images were enhanced by using a method of contrast limited adaptive histogram equalization, and then a method of median filter was applied to the processed image in order to reduce the noise, in order to get the low-frequency information of the X-ray images. Secondly, the relatively high-frequency information of the original image was got by Laplacian filter. Finally, the weighted sum of the previous two processed images was the goal image. Experimental results show that the method can largely reduce the strong noise, and preserve the image information interested in better, and help the study of container X-ray image.

3D data set LOD visualization based on depth-oct-tree

2010, 30(1):  47-49. 

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This paper put forward the concepts of breadth-oct-tree and depth-oct-tree. It analyzed their logic structures and storage structures, which were applied in 3D data set visualization. Depth-oct-tree was used in LOD volume rendering algorithm which was tested on a sismic wave data set. Compared with the traditional method, the new algorithm was much faster. On the contrary, the traditional method cannot be applied in PCs due to the large amount of time and space required. The results indicate that the new method can improve the performance of volume rendering. Especially, combining the whole and part volume rendering method, the speed was higher and more elaborated observation was achieved.

Digital watermarking algorithm based on template and image feature

2010, 30(1):  50-53. 

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As to the digital watermarking based on local feature is lack of robustness to non-scaling attacks,this paper put forward a watermarking algorithm based on template and local feature. Firstly, the template information was used to correct the non-scaling attacks. Then the Harris-Laplacian detector was utilized to extract steady feature points from the host image, and the local feature regions area were determined adaptively according to the feature scale theory; finally, the digital watermarks were embedded into the local feature regions using cirque quantization. Experimental results show that the proposed scheme is not only invisible and robust against common signals processing, but also robust against the geometric attacks, in particular,the non-scaling.

Image segmentation based on wavelet mutation particle swarm optimization and fuzzy entropy

2010, 30(1):  54-57. 

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Image segmentation algorithm based on Particle Swarm Optimization (PSO) and fuzzy entropy cannot have satisfactory performance because the classic PSO easily falls into local optimization and premature convergence. Concerning this shortcoming, a new segmentation algorithm based on wavelet mutation PSO and fuzzy entropy was proposed. The new algorithm used wavelet mutation PSO to explore fuzzy parameters of maximum fuzzy entropy, and to get the optimum fuzzy parameter combination, and then obtained the segmentation threshold. According to the comparison of the experimental results between the new algorithm and the other two algorithms, the new algorithm is of good segmentation, low time cost and self adaptivity.

Object detection method with tracking compensation based on space-time background difference

2010, 30(1):  58-60. 

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Varying illumination, noise of camera and inadequate background update are the challenges in the current video object detection. A moving object detection method with tracking compensation in color images based on spacetime background difference was proposed. First, this paper established a Gauss background mixture model; and eliminated the varying illumination by adding impact factor in the color image difference. Then frame difference and domain difference were fused with moving tracking seeds compensation to get the seeds of real moving objects; based on the rough foreground which was got by background difference, according to the filter method based on the moving seeds which connected the region of moving objects, the final real and integral foreground target was found. The data collected from many real surveillance videos show that the accuracy and integrity of object detection are greatly improved by using this method.

Image-analogies based super resolution for remote sensing images

2010, 30(1):  61-64. 

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Due to the long distance between satellite camera and the site, the resolution of remote sensing image is low. In order to get high resolution image, Image Analogies (IA) technology and cubic convolution interpolation algorithm were combined, and a new idea that studied the highfrequency details of the high resolution image directly in the learning set was proposed. The experimental results show that this method can not only amplify images much more sharply, but also generate more reasonable details to enhance the image than general image analogies method. Thus, the amplified remote sensing image becomes more vivid.

Local description and retrieval method for binary image contour

2010, 30(1):  65-67. 

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This paper proposed a strategy for retrieving binary images based on contour decomposition and local description. Firstly, the contour of object was extracted from binary image and decomposed by special method, and then the set of reference points were acquired. For each reference point, the curve to which the point corresponds was gained. A set of vectors which connect the reference point to all the points in the curve were computed. After that, Fourier transform was applied to the set of vectors and Fourier coefficients were treated as the eigenvector of the reference point. As a result, the image could be represented by a set of feature vectors in feature space. Finally, the distance between two images could be calculated by the method of points matching and the retrieval of binary images could be implemented. Experiments show that this method has higher retrieval precision, compared with some classical methods.

Corner matching method of constraints of distance combining local and global information

2010, 30(1):  68-70. 

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Image matching technology has important applications in many fields. A corner matching method of the constraints of distance was proposed to solve the rotation and translation problem between two images. Firstly the values of corners were utilized to achieve coarse matching election, and then the local and global distance between the corners was combined to select the matching corners. The experimental results show that the methods can achieve accurate matching of no unmatched conners with high accuracy, certain robustness to noise, and as a result of the main use of the distance relationship between two corners without complex calculations in the matching process, so it achieves a substantial reduction in matching time, and also has the practical value.

Moving objects detection approach based on adaptive mixture Gaussian background model

2010, 30(1):  71-74. 

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An adaptive approach to detect moving objects with a static camera was proposed in this paper. Based on the assumption that the probability of the same pixel covered by the same intensity of the car is the least, the initial background was established and the number of Gaussians for each pixel on-line was chosen. In order to update the Gaussians parameters, the learning rate should be updated online according to the relationship between the pixel and its adjacent pixels. Lastly,the moving objects were detected by background subtraction. Compared to the moving objects detection approach based on conventional mixture Gaussian model, this approach has preferable adaptive performance, and can deal with changes in scenes rapidly.

Voronoi diagram generation algorithm based on Delaunay triangulation

2010, 30(1):  75-77. 

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Considering the problem that the algorithm of building autoconnected Delaunay triangulation and indirectly building Voronoi diagram is of low efficiency, an improved Voronoi generation algorithm based on auto-connected Delaunay triangulation was presented. The seed triangle was rapidly generated by one side of the convex hull. The notion of half closedborderpoint was proposed. The algorithm removed closed-points and half closedborderpoints in the process of expanding triangle and improved the speed of generating Delaunay triangulation.Then, the notion of ordered target triangle was defined. It quickly found ordered target triangles and generated the non-ray Voronoi diagram. Considering the characteristics of convex hull, a ray Voronoi diagram was generated by three infinite points. The experimental results show that the efficiency of the improved algorithm is obviously improved.

Optimized image denoising method based on neighborhood threshold shrinkage approach

2010, 30(1):  78-81. 

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Wavelet denoising is a new image denoising method.Neighborhood threshold shrinkage method is one of the wavelet domain threshold image denoising methods. Its principle is that according to the square of all the wavelet coefficients in the neighborhood window,it processes the wavelet coefficients in the center of the window. An improved image denoising method of optimization in the wavelet domain was proposed. At first, the proposed method determined an optimal threshold and the window of the neighborhood using unbiased risk estimation of mean square error criterion in the wavelet domain for each subband; then introduced a detailed enhancement factor of P, and a mapping function in order to optimize the shrinkage factor for the wavelet coefficient; at last, the estimation of the true coefficients were obtained by the shrinkage estimation of wavelet coefficients. The experimental results show that the proposed method obviously outperforms the neighborhood threshold shrinkage method in the ratio of peak signal to noise. At the same time, it effectively enhances image details, and effectively improves the visual quality of the image.

Image enlargement based on non-uniform B-spline interpolation algorithm

2010, 30(1):  82-84. 

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Image enlargement and reduction are widely applied in real life. The popular image processing software commonly carries out magnification and reduction by interpolation methods. The realization of a variety of interpolation algorithms is now a hotspot for research. Now a new interpolation algorithm based on the nonuniform Bspline curve was proposed. By this way which applies a nonuniform parameterization method different from the traditional algorithms, the objective image after interpolation can maintain a higher resolution and good smoothness. As for the serrated phenomenon on image edges, the algorithm interpolates the image edges with the bi-cubic algorithm when interpolating. Thus, the visual effect on edges can be optimized. The experimental results show that the image becomes clearer and smoother by the new way. On the image edges, the serrated phenomenon is eliminated and a good visual effect is achieved.

Automatic path finding method for real-time rendering of 3D scene

2010, 30(1):  85-89. 

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This paper presented a path-finding method in real-time 3D scene. The polygons in scene models were regarded as the searching elements, and the virtual scenes were abstracted into intermediate result in the form of connected graph. In this intermediate result the heuristic search was made according to the scene nodes connectivity properties. A path searching task management mechanism was also carried out to balance the processing time of each frame loop. The proposed method could work without any factitious mark and script information in the scene and high processing had been achieved.

Personalized ontology-based semantic annotation and retrieval of image model

2010, 30(1):  90-93. 

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In order to solve the problem that it is difficult to implement semantic retrieval of image, a novel ontology-cored semantic annotation and retrieval model of image was proposed, which constructed a personalized ontology to describe image, extracted the image semantic features based on the concept set and used inter-relationship "Is-A" of ontology to measure the similarity between the images and query. The difficulty lies in the personalized evolution of the top ontology, as well as the semantic similarity measure based on concept set and inter-relationship "Is-A". This model was implemented and some related experiments were carried out. The experimental results validate the retrieval accuracy as high as 88.6%, significantly higher than the traditional keyword-based and generic ontology-based image retrieval models, which realized intelligent retrieval of image.

Novel approach for texture retrieval using nonsubsampled Contourlet transform

2010, 30(1):  94-97. 

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To increase the validity of texture feature extraction in content-based image retrieval system, a novel approach for texture image retrieval was proposed. This approach was based on the NonSubsampled Contourlet Transform (NSCT). The means and variables of NSCT coefficients matrix in different subbands and various directions were extracted to form the feature vectors which were regarded as indexes of texture images in image database. Two similarity functions were used to compute the similarity between images. A texture retrieval system based on query image was developed. Compared to the wavelet package transform, this approach can not only reduce the dimension of feature vectors, but also get higher accuracy and speed of retrieval.

Matching Capabilities Comparisons of Similarity Measurements

CHEN WEIBING

2010, 30(1):  98-100. 

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Image matching performance and real-time capability mostly depend on how to choose similarity measurement method of image matching algorithm. In order to analyze this topic in-depth, the paper carried out a series of simulation experiments for the matching performance evaluation of four similarity measurements (NProd, PC, MSD and equalization MSD) through noise addition and image distortions. The image distortions include picture orientation, image scale change, illumination intensity change, clouds cover, and so on. The experimental results were compared with those from the matching performance, adaptive capacity and realtime capability. Analysis and theoretical demonstration of the results were also given.

Networks and communications

Novel scheduling algorithm in high-speed crossbar and its performance analysis

2010, 30(1):  101-103. 

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This paper analyzed the reasons for which the high-speed crossbar scheduling algorithm iSLIP has a serious deterioration of performance under burst traffics. With reference to the ideas of LQF/iLQF, this paper proposed a novel input-queued crossbar scheduling algorithm called iPGQM (iterative Parallel Graded-Length Queue Matching). Simulation results show that iPGQM has the same performance as iSLIP under uniform traffics. Furthermore it has better performance than iSLIP under burst traffics. Especially in heavy load conditions, iPGQM not only achieves higher throughput, but also reduces the average delay about 10% compared with iSLIP algorithm.

Soft interruption handling mechanism to optimize handling performance for Linux network

2010, 30(1):  104-107. 

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As the most strict bottom half handling mechanism of interruption on time accuracy, soft interrupt mechanism plays an irreplaceable role in the process of handling network packet. However, unalterable circular check times taken by soft interruption handling function causes system unable to handle packets effectively under high traffic load. This paper presented a methodology of adaptive circular checking times to optimize soft interruption handling mechanism. Test shows that compared with the former mechanism, current soft interruption mechanism can handle more soft interruption routines in the same condition, i.e. capturing more network packets. The methodology improves the system′s capacity to handle soft interruptions and optimizes the handling capability of Linux network.

Maximum matching algorithm with QoS in grid resource scheduling

2010, 30(1):  108-110. 

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Concerning the low scheduling ratio caused by complicated QoS process and precise match in resource scheduling of grid, in this paper, the authors classified QoS parameters as according to their characteristic, defined QoS parameters distance and estimated QoS parameters similarity. A QoS managing model was presented, and a maximum matching scheduling algorithm was described based on the model. Finally simulations were performed to compare the performance of the maximum matching scheduling algorithm with that of the multiple QoSbased resource scheduling algorithm. The experiments show that the maximum matching scheduling algorithm is efficient on system throughput and task fulfilling ratio and resource utilization ratio within grid computing environments.

Slot synchronization algorithm in Ad Hoc network based on NTP

2010, 30(1):  111-113. 

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A multichannel slot structure based on Time Division Multiple Access (TDMA) in Ad Hoc network was designed. According to the basic principle of Network Time Protocol （NTP）and the new slot structure, an algorithm for slot synchronization of the whole network was proposed. The proposed algorithm inherited slot synchronization of point to multi-point wireless communication system. The initial slot time synchronization of the whole network was completed after the time adjusting of master-slave synchronization, then the step of slot interactive synchronization started. In this step, the periods of slot interactive synchronization must be set so properly according to the guard interval length, the clock differences and the moving speed of network nodes that not only the network load was not increased, but also the slot collision was avoided. Simulation results show that the proposed algorithm has minimal time deviation and can realize synchronization rapidly. The method can be applied to Ad Hoc network based on TDMA.

Peer-to-peer based personalized Web information retrieval

2010, 30(1):  114-117. 

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To overcome the shortcomings of the Web search engines on scalability, collaboration, and personalization, a personalized P2P based Web information retrieval was proposed based on wide distribution, collaboration and selforganization. The strategy of users’ collaboration and sharing was defined. That is, user’s query topics were used to cluster the queries, to store data and to route queries. Towards the goal of providing more humanized and personalized retrieval by utilizing users’ collaboration, some algorithms and mechanisms were designed in respect to building user’s favorite list vector collaboratively, clustering the queries to update the user’s interest topic by the semantic similarity, structuring the inverted index based on per unit of keyword group, and forwarding the query among peers according to the similarity of topic. The experimental results show that the prototype system can speed up the searching process, reduce the network load and improve the accuracy of the search.

File system encapsulation mechanism in embedded software development platform

bo xianHe

2010, 30(1):  118-120. 

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Due to the variety of operating systems used in the embedded software development and the application correlation of embedded software, the embedded operating system is commonly encapsulated to impove its functions in the embedded software development platform. The function of file system in an embedded operating system is too simple to satisfy the function demand of complicated software such as the communication application software. In this paper a file system schema which combined file management, memory device, FTP server and foreground-background communication mechanism was presented and its implementation based on VxWorks was analyzed. In addition, the programming interface of the scheme was suggested.

Data caching algorithm in metropolitan vehicle network

2010, 30(1):  121-123. 

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Data caching is an important technique in metropolitan vehicle networks. It can increase data availability and significantly improve the efficiency of information access by reducing the access latency and bandwidth usage. However, designing efficient caching algorithms is nontrivial when network nodes have limited memory. This paper analyzed how to cache with the help of benefit function, and proposed a way of using local access frequency and neighboring node access frequency to construct the benefit function. The authors simulated the algorithm using a network simulator (NS2), and its advantage was demonstrated in city scenarios.

Improved DBA algorithm based on traffic prediction

2010, 30(1):  124-126. 

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P-DBA based on traffic prediction was presented, which established different linear prediction models for the ShortRange Dependence (SRD) and SongRange Dependence (LRD) traffic and drop prediction to reduce the bandwidth waste when the variation of traffic was rapid, while Optical Network Unit (ONU) used a new local fair scheduling policy adapted to the prediction strategy. The simulation result shows that end-to-end delay, and packet loss rate has been improved obviously, compared with DBAM algorithm.

Node data prediction based on SVR in wireless sensor network

ZOU ChangZhong

2010, 30(1):  127-129. 

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Wireless sensor network is mainly used in collecting the environment information, but due to limited energy and security some nodes are easy to break down, thus these nodes will not collect data. How to forecast the sequent data will become a key problem. In this paper, a data estimating algorithm based on Support Vector Regression (SVR) in Wireless Sensor Network (WSN) was proposed which used the previous data to estimate the sequent data. The simulation shows that the scheme is efficient and of less prediction error.

Link failure tolerance scheme in clustering wireless sensor network based on network coding

2010, 30(1):  130-133. 

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In many emergent applications, Wireless Sensor Network (WSN) must be able to guarantee highly reliable data transmission, and therefore it becomes more and more important to study the fault-tolerance of data transmission fault-tolerance in WSN. The 1+1 data protection model will consumes the energy of sensor node dramatically due to its additional overload. This paper, aiming at reducing the consumption of sensor energy, proposed a scheme based on network coding in clustered WSN, which can not only achieve tolerance of link failure, but also reduce the number of data packets in network. The method has been proved to be more energyefficient than the model of 1+1 data protection.

Delay performance in wireless multi-hop networks

2010, 30(1):  134-136. 

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Wireless multi-hop networks have a wide range of application forecast. It is crucial to develop feasible methodologies and techniques for accurately analyzing, predicting and guaranteeing end-to-end delay performance over multi-hop wireless communication paths. Through extending the link-layer equivalent bandwidth model, a lower bound of delay-bound violation probability was derived. Analytical results were verified by extensive computer simulations under different traffic load and wireless channel conditions. Multi-hop delay performance is proved to be much more sensitive to maximum Doppler rate than channel service rate.

Cross-layer handover optimization using grey prediction model

2010, 30(1):  137-139. 

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With the fast development of mobile Internet, the wireless community has been increasingly looking for a framework that can better provide seamless mobility. Firstly, this paper processed received signal strength smoothly using improved Exponentially Weighted Moving Average (EWMA) algorithm. Then, a fast cross-layer handover scheme based on movement prediction in mobile WIMAX environment was proposed. Prediction is achieved by grey predictive model with keeping track of the signal strength of mobile users. With the help of the prediction, layer-3 handover activities are able to occur prior to layer-2 handover, therefore, total handover latency can be reduced.

Split algorithm of binary tree with priority and its simulation under free access channel

2010, 30(1):  140-142. 

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A modified binarytree based algorithm with priority scheme was proposed in this paper. The algorithm can guarantee the priority service to access channel in high probability while avoiding congestion. The main factors that affect the grouping measure for priority services and its transmission efficiency were analyzed also in the paper. Computer simulation experiments were carried out under the condition of two priorities, while set different arrival rate, initial access probability, the proportion of high priority service among whole traffic and the retransmission probability, to analyze the delay and throughput of blocked and free access channel. The result indicates that the algorithm is efficent and reliable.

Artificial intelligence

Multi-class cluster support vector machines

2010, 30(1):  143-145. 

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Based on the idea of nonparallel hyperplanes, a novel multi-class cluster support vector machine method was proposed to settle the multi-class classification problem of support vector machines. For a k-class classification problem, it trained k-hyperplanes respectively, and each one lay as close as possible to self-class while apart from the rest classes as far as possible. Then, labels of new samples were determined by the class of their nearest hyperplane belonging to, thus the inherent limitations of OAO and OAA methods can be avoided, such as “decision blind-area” and “unbalanced classes”. Finally, experiments on UCI and HCL2000 datasets showed that the proposed method outperformed traditional OAO and OAA etc. methods in terms of recognition accuracy significantly.

Exhaustive genetic algorithm based on GC-GM for multiple sequence alignment

2010, 30(1):  146-149. 

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Multiple sequence alignment is an unsolved NP-complete combinatorial optimization problem. This paper described a new exhaustive genetic algorithm based on Gap Crossover and Gap Mutation (GC-GM) for multiple sequence alignment by genetic operation on gap matrixes reassembled. The approach was examined by using a set of standard instances taken from the benchmark alignment database BAliBASE. Numerical simulation results were compared with those obtained by using the Clustal W algorithm and showed the effectiveness of the new approach.

Dynamic simulation of chemistry experimental phenomenon based on particle system

2010, 30(1):  150-152. 

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Chemical experimental phenomenon is a class of irregular fuzzy object, and difficult to simulate by traditional modeling method. A dynamic simulation for experimental phenomenon based on particle system was proposed, a unified model by parameterization was set up, and the dynamic simulations of flame, bubble, etc. were realized. The experimental result shows that the simulation method can improve the vividness and fidelity of the fictitious experimental scenes effectively.

Application of back propagation artificial neural networks in bug analysis

2010, 30(1):  153-155. 

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Due to the complex business requirements, financial software system could be giant in scope and complex in system logic. During the development and maintenance of such software system, the detection and analysis of the system defects and errors are difficult and time-consuming in most of the circumstances, which usually is deemed as the bottleneck of the whole project after the midstage. In this paper, by implementing the Back Propagation (BP) algorithm, a defect analysis system was designed for the enhancement project of an Internetbased transaction trading system. The experimental results show that it does improve the developers' efficiency and productivity in defect detecting and fixing, which consequentially accelerates the project progress.

Algorithm of numerical attributes reduction based on similarity rough set

Min WU

2010, 30(1):  156-158. 

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As to the problem of interferential or noisy data reduction, an attribute significance evaluation principle was proposed based on the difference and similarity of attributes within objects. A numerical attributes reduction algorithm was constructed based on similarity rough set model, and it was extended to canonical rough set too. Experiments were carried out on two data sets, one is of license plate characters and the other is of UCI handwritten number, the experimental results show that the proposed algorithm can generate simpler but more powerful rules set than other reduction algorithms.

Dynamic diffusion particle swarm optimization

2010, 30(1):  159-161. 

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Dynamic Diffusion Particle Swarm Optimization (DDPSO) was proposed to improve the poor search quality of the standard PSO for optimizing highdimensional function. A nonlinear function was introduced to adjust the inertia weight and it added a dynamic random number in the updating mode of particle velocity to enhance the searching ability. Meanwhile, particles were diffused again under certain conditions in order to ensure diversity of the swarm. Simulations show that dynamic diffusion particle swarm optimization has outstanding performances in highdimensional function optimization compared with standard or other modified PSOs.

Semantics Web service composition engine based on topic maps

2010, 30(1):  162-166. 

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With regard to the problems like flow control and throughput of Web service composition, a topic-map-based semantics Web service composition engine was proposed, in which some Web services would be described via ontology and topic map. Web services and topic maps were abstracted by using these description languages which included OWL-S and XTM. Web service topic was employed to express semantics Web service, which aimed to use characteristic of topic maps. And topic maps expediently implemented positioning and navigation of information resource, such as Web services, which made states and goal of Web services definite. Thus, to define UDDI registration(UDDIr) and retrieval capability(UDDIs), grammar checking (GD) and semantics recognition capability (SI), similarity (STS), matching (STM), sufficiency (STF) of Web service topics, facet classification capability of Web service topics characteristics (SFC), access right of Web service topics (STP), facet depth decision (FDD) and interoperability capability (STC) to set up service composition engine approach, and employ mathematical method to describe and define. Finally, Java was employed to develop Web service composition engine. The experimental results show that it is feasible and effective.

Novel particle filtering algorithm with application to bearing-only tracking

2010, 30(1):  167-170. 

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The conventional bootstrap filter suffers a main drawback of not incorporating the latest observations. Therefore, this paper proposed a Kalman Particle Filter (KPF) algorithm, and applied this new algorithm to bearingonly target tracking. An improved scheme was presented to handle this problem and yield a Kalman particle filter. The underlying idea of the new algorithm is that each particle is updated using Kalman filter incorporating the coming observations. A bearingonly tracking model was experimented and compared with bootstrap filter and KPF. The experimental results verify its superiority.

Application design of sustainable simulated algorithm based on hierarchical fair competition model

2010, 30(1):  171-174. 

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A kind of medical experiment arrangement arrangement problem, which was a constrained optimization was solved by using an improved Simulated Annealing algorithm based on Hierarchical Fair Competition Model (HFCSA) through modifying the definition of individual, designing new coding method and growth pattern, and proposing efficient operators. The results show that the time expense of the new optimal solution is 77% of the older one. The success to solve medical experiment arrangement problem has widened the HFCSA’s application field and found out a new way for solving some similar constrained optimization problems.

Support vector machine ensemble model based on KFCM and its application

2010, 30(1):  175-177. 

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To further enhance the regression prediction accuracy of support vector machine, a Least Squares Support Vector Machine (LS-SVM) ensemble model based on Kernel Fuzzy C-Means clustering (KFCM) was proposed. The KFCM algorithm was used to classify LS-SVMs trained independently by its output on validate samples, the generalization errors of LS-SVMs in each category to the validate set were calculated of the LS-SVM whose error was minimum would be selected as the representative of its category, and then the final prediction was obtained by simple average of the predictions of the component LS-SVM. The experiments in short-term load forecasting show the proposed approach has higher accuracy.

Algorithm of anomaly detection based on centroidal Voronoi diagram

2010, 30(1):  178-180. 

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Network anomaly detection has been an active research topic in the field of intrusion detection for many years. However, it has not been widely applied in practice due to high false alarm rate, etc. Based on the centroidal Voronoi diagram, a new algorithm of anomaly detection was proposed in this paper, in which the centroidal Voronoi diagram was used in the clustering of sample data first, and then the point density was computed out according to the results of clustering for each sample point, which was used to determine whether the sample data was abnormal or not. Finally, a series of experiments on well known KDD Cup 1999 dataset demonstrate that the new algorithm has low false positive rate while ensuring high detection rate.

Information security

Behavior-based virus detection method using multi-class support vector machine

2010, 30(1):  181-185. 

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In order to achieve specific functions, computer viruses are of some special behaviors different from those of the normal programs. Appling Support Vector Machine (SVM), the paper created a space of virus API feature vector and amplified the difference between normal programs and computer virus with the help of information entropy. By training a classifier, a hyperplane was found, which could divide the API space into two parts, each of which represented one kind of the programs. Moreover, the paper collected behaviors of different kinds of viruses. Through statistics, analysis and calculation on amount of samples' API calls, the amount and distribution patterns of APIs were exposed. As most viruses' behaviors are finite, the paper set 2100 as the length of API sequence, thus detecting most test viruses. Compared with previous virus detection methods, the proposed method is more practical.

Lossless data hiding for color images based on prediction error difference expansion

2010, 30(1):  186-189. 

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Applying Tian's difference expansion to color images, this paper proposed a lossless data hiding method for color images based on prediction error difference expansion. To solve the quality decline of stego-images from excessive modulation to pixels, the proposed method dispersed smaller expansion to two color components, and improved histogram shifting technique. Experimental results show that both the capacity for embedding users' message and the stego-image quality are significantly improved, when compared with other algorithms.

Network risk assessment model based on rough graph

2010, 30(1):  190-195. 

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Concerning the characteristic that the information system obtained from doing network security analysis is rough and incomplete, this paper compared the process of attack to the rough and uncertain relationship mining process by analogy, and proposed a new network risk assessment model based on rough graph. The model is made up of three parts of main contents including node rough correlation network, attack graph generation algorithm based on rough graph and network risk maximum flow analysis algorithm. In the end, this paper used a representative example of network system to explain the method of model, and verified the correctness. Model advantage analysis shows that the model can reflect the actual situation better than the previous attack graph model and risk assessment model, and the conclusion and safety recommendations are more accurate and reasonable.

Covert communication based on subliminal channel in elliptic curve digital signature algorithm

2010, 30(1):  196-197. 

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There are narrowband and broadband subliminal channels in the Elliptic Curve Digital Signature Algorithm (ECDSA)，but broadband subliminal channel cannot be safely used. Therefore, the real-time test of narrowband subliminal channel was done. The reasonable bit rate of the sent message was confirmed when the capacity and real-time requests of narrowband subliminal channel were satisfied. The result shows narrowband subliminal channel can be effectively used in ECDSA.

Encryption approach to chaotic synchronization communication by TD-ERCS discrete system

2010, 30(1):  198-202. 

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The complexity of chaotic pseudorandom sequences generated by the new TD-ERCS discrete chaotic system was analyzed in detail, and the simulation results show that TDERCS is a discrete chaotic system with the great steady complexity. On the basis of this, the authors presented a doublechannel encryption approach to generate chaotic pseudorandom sequences based on TD-ERCS discrete chaotic system. In this approach, the chaotic oscillator at the transmitter was used to generate digital key and masking signal, and chaotic sequence generated by the driver system was turned into encryption keys in CPRNG. The information signals were first encrypted by the key and then masked by the masking signal. The masked signals were transmitted through one channel, the other channel was used to transmit the single variable which was coupled to the receiver to drive two chaotic oscillators to synchronize. The simulation results show that the theoretical analysis is in accordance with the experimental result. The cryptosystem is of higher level of security, synchronization and algorithm complexity, and it can be easily implemented by software.

Chaos-based secure dual self-recovery watermark algorithm for image authentication

2010, 30(1):  203-206. 

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To improve the security of dual self-recovery watermark, a chaos-based dual selfrecovery watermark scheme for image authentication was proposed in this paper. In the proposed scheme, the chaotic map was first adopted to encrypt the dual watermark data, and then the data were embedded into the image block of less significant bits. And then the authentication data of each block was randomly generated with reference to its content and the recovery watermark embedded according to the chaotic mapping. Theoretical analysis and simulation results show that the proposed scheme can not only maintain the good tamper recovery quality and invisibility of dual self-recovery watermark, but also improve the security against the only-content tampering attack and the dictionary searching attack.

Improved model of process behavior detection and implementation

2010, 30(1):  207-209. 

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To detect malicious program, the disadvantages of current detection mechanism were analyzed. The extension of process behavior concept was redefined. A detection model of difference comparison and process dynamic behavior analysis was proposed. The critical technology and realization were given. The experimental results indicate that the detection model excels traditional detection method in versatility and effectiveness.

Detection of suspicious communication behavior of one program based on method of difference contrast

2010, 30(1):  210-212. 

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In allusion to the damage of baleful program for computer users and its fast growth in quantity, a detection system based on network communication behavior data of one program was proposed. A detection model of suspicious communication behavior based on difference contrast was emphasized. The cooperative work diagram of each module of the system and program code of critical technology of the system were given. The test result shows that the system can detect network communication, communication process and domain name for one program.

MPEG video authentication scheme based on content feature

2010, 30(1):  213-216. 

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An MPEG video hierarchical content watermarking authentication scheme that utilized the local and global features among video frames was proposed to find out whether the content of video had been maliciously changed or not. The two employed kinds of features in the scheme, the global one and the local one, are semifragile, which can tolerate the legal content persistent operation and sensitive to the tamper operations. The global feature was abstracted from the relation coefficients of DC coefficient matrix in the I type pictures, which could detect the content tamper with a lower computation payload. After the tamper frame was decided, the tamper positions could be further localized with the local features. Experimental results show the satisfying performance of the proposed scheme. The fit choosing strategy in this scheme can reduce the computing payload about 20 percent. In a word, the content feature based video authentication scheme can lighten the way to build practical video authentication methods.

Software watermark based on structure transform of PE file import table

2010, 30(1):  217-219. 

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By analyzing the structural characteristics of import table and the calling approach of function in the module, a new software watermark based on structure transform of PE file import table was proposed. The new method made digital watermark information hidden in the sequence of import modules and functions in the PE file. Analysis shows that the method is more covert and robust than that utilizing redundant PE file space or resources structure, and it provides a more secure way of software copyright protection.

Weighted-Join-exit-tree-based contributory group key management scheme for key rekeying

2010, 30(1):  220-223. 

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Contributory group key management works on how to make the system more scalable and time efficient due to relatively heavy computation cost. In this paper, a contributory group key management based on Weighted-Join-Exit-Tree, named as WJT was presented to get better time efficiency in key updates. First, a new key tree topology was put forward. Then, exit tree was organized as a weighted tree to reduce the key updating complexity when user leaves. Last, optimal capacity of the exit tree and the condition of activation of the exit tree were selected through optimization method. Theoretical analysis and simulations show that the asymptotic average join time and leave time are reduced to O(1).

Typical applications

Forecasting and analysis on long-term/mid-term electric load of city by GA-BP neural networks

2010, 30(1):  224-226. 

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Due to the industrial structure adjustment, the change of resident consumption ability and pattern of consumption, and market-oriented and so on, long-term/mid-term power load forecasting for urban plans faces considerable difficulties. In the past two years, the methods that combined genetic algorithm and Back Propagation (BP) algorithm have been used for short-term power load forecasting rather than long-term/mid-term power load forecast of electricity. In this paper, a neural network prediction model with combination of genetic algorithm and BP neural network was established; the example in Nanchang was given to validate the accuracy of the algorithm, by comparing with the traditional BP neural network and Simulated Annealing (SA) prediction. Then the basic electricity load of Nanchang in the next dozens of years was forecasted and analyzed.

Chironomid larvae recognition method based on wavelet packet decomposition and fuzzy support vector machine

2010, 30(1):  227-229. 

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The chironomid larvaes enter the watersupply system through transmission pipeline. Although there are no indications that chironomid larvae pose a threat to public health, their presence is still not appreciated because most people associate the organisms with low hygiene. In accordance with the characteristics of the organisms, this paper studied chironomid larvae images recognition method based on wavelet packet decomposition and Fuzzy Support Vector Machine (FSVM). The energy features of subgraph decomposed by wavelet packet, color information entropy, and the shape features of plankton were selected to construct feature vector for FSVM that is used to classify the image. The experimental result shows the method is effective for freshwater plankton images, such as chironomid larvae, cyclops and harpacticoida, and provides the basis for the prevention and treatment of chironomid larvaes in water plant.

Method of specific audio retrieval based on randomly segment

2010, 30(1):  230-232. 

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This paper proposed a specific audio retrieval method based on random segment in order to decrease the retrieval time for relatively long object in the total retrieval of audio retrieval. The whole retrieval process was composed of random segment retrieval and total matching: the first was to select a segment from template model as object to retrieve in stored signal and the second was to judge whether the potential object signal was the template model based on random segment. Then using this method in computing feature distance directly and histogram intersection retrieval, the experimental results show retrieval accuracy over 90% and average retrieval time declined to the ratio of random segment to template model multiplying total retrieval time.

PID control model and method based on process neural network identification

2010, 30(1):  233-235. 

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Concerning PID process control of nonlinear dynamic system, a control model and its method of PID parameter adaptive tuning based on Process Neural Network (PNN) identification were proposed in the paper. Using the learning mechanism of PNN for time-varying input-output signals of dynamic system, the PID control with parameter adaptive matching was implemented by tracing change sensitivity information of the output with the controlling input of the controlled object by identifying the controlled object under certain optimal control rule. The PID control system structure and corresponding realization mechanism based on PNN identification were presented in the paper and the experimental results verify the effectiveness of the model and algorithm.

Application of nonlinear feature extraction and least square support vector machines for fault diagnosis of chemical process

Liang XU

2010, 30(1):  236-239. 

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The nonlinear feature extraction (Kernel Principal Component Analysis（KPCA） and kernel Independent Component Analysis (ICA)) was used to eliminate the uncorrelated component from input data, and reduce dimension in the paper. Kernel principal component analysis adopted a kernel function to map input data into feature space and calculate linear PCA. Kernel independent component analysis extracted independent component by linear ICA transformation in the KPCA whitened space. The extracted features were taken as the input of Least Square Support Vector Machine (LSSVM) classifier. Incorporating nonlinear feature extraction into LSSVM served as a new method for intelligent fault diagnosis. The proposed method was applied to the fault diagnosis of lubricating oil process for a petro-plant. The effectiveness of the proposed method is verified.

Research on topic maps-based ontology information retrieval model

LI QingMao XingJiang Yang Xiang-Bing Zhou

2010, 30(1):  240-242. 

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Ontology is normative, explicit and reusable when defining the domain concept, so it can be combined with topic maps to organize information resource for semantic navigation. An information retrieval model based on topic maps and ontology was proposed and defined formally. Firstly it specified a domain of tourism document. Secondly it defined the ontology and topic maps of tourism document in order to normalize query that user directly input in natural language, and identified the users real meaning of search. Thus, it can expand user' semantic search. Therefore analyzed the effect of the ontology was analyzed, and a valuable function of semantic navigation and sorting the retrieval result correlated with user's query was shown. Finally，the experimental result shows that the topic mapbased ontology information retrieval model can perform better than the traditional model.

Dynamic differentiated pricing for multi-class services selection and resource allocation

2010, 30(1):  243-245. 

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In differentiated services network, users have to choose reasonably among multi-class services with differentiated QoS under budget constraints, while the network has to provide the required services effectively with limited resource. Service choosing problem was modeled as an optimal services composition one whose solution corresponded to specific number of service tokens which then instructed the DSCP selection at user end. Service providing problem was solved by a heuristic algorithm in which service prices were tuned dynamically at network end on a small timescale according to users’ demand variation, while resource provision was adjusted on a large timescale based on service prices logicality. Simulation results show that the mechanism can improve users’ total utility markedly and promote the deployment of differentiated services.

Researches on disaster recovery methods of long-running applications based on checkpoint

2010, 30(1):  246-248. 

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A new application disaster tolerance method was proposed to meet the disaster tolerance requirements of time-constrained longrunning applications. The method saved the middle running states of applications periodically and transfered these states to backup servers asynchronously. After disaster happened, application could resume from the latest checkpoint. Method of setting the checkpoint parameters was provided too. The prototype has verified the efficiency of the method in simulation environment.

Investigation of visual inspection method for silicon solar cell

2010, 30(1):  249-252. 

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Quality inspection plays an important role in the process of silicon solar cell production. Based on the characteristics of silicon solar cell, a visual inspection method for silicon solar cell was proposed. Shape dimension was measured by line and circle fitting and based on which outline edge defect was implemented by calculating the distance from the edge points to fitting lines and circles. Since the surface texture structure is more complicated after screen printing, a multi-template matching method combined with image subtraction was adopted to detect the defects of screen printing. The experimental results show that the silicon solar cell inspection method is stable, reliable and of high precision, which achieves a rapid and effective silicon solar cell inspection.

Investigation of occupant distribution in intelligent buildings based on wireless sensor network

2010, 30(1):  253-254. 

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With Wireless Sensor Network (WSN) technology, building automation system monitors the occupant distribution, so as to realize the light control, Heating, Ventilation and Air Conditioning, fireproofing and intelligent security. Multipath effects of WSN influence the RSSI (Received Signal Strength Indication) accuracy seriously in some applications. To resolve this problem, ECDF (Empirical Cumulative Distribution Function) method was introduced in this paper. Through the conditional probability and radio map method, ECDF processed the data and prsented the distribution results. By training ECDF with indoor sensor data, the results indicate this method determines the occupant distribution effectively and robustly.

Audit and control of trust evaluation in grid

2010, 30(1):  255-258. 

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Objective evaluation of trust value is the basis of trust model validity, but the subjectivity of evaluation makes it hard to achieve. Audit is one of the effective ways to this problem. In this paper, the authors presented an approach of trust evaluating model with audit function, by the support of basis running data. The process included standardization, distance calculating, and abnormity evaluation detecting and correcting, thus implementing the control of evaluation. As to the model requirement, the authors analyzed the refresh periods of audit, and an audit algorithm was put forward. Finally simulations were performed to validate the audit. The experimental results show that the audit is efficient on trust model stability and at the same time is helpful with the throughput of grid.

Research and design of 3G file system for smart card

Dai-ping LI Hong-zhi GUO Xiao-hu MEI

2010, 30(1):  259-262. 

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Research and design of three generation file system for smart card on flash memory were made, introducing log technology and power failure protection to assure smart cards file system reliability, data consistency and integrality. Memory space was assigned according to byte. Mechanisms of valid space collection and reuse improve the using rate of memory space. Technology of wear leveling and page mapped prolong the flash storage life-span, and the design of efficiency memory management improves the rate of data retrieval. Consequently, the whole performance of smart card is strengthened. The simulation makes sure the file system fit 3G EVDO card.

Recognition for change-point of traffic flow binary linear regressions based on projective transform method

2010, 30(1):  263-265. 

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The previous researches mainly focused on traffic flow state recognition in advance (namely traffic flow forecasting) and realtime recognition (namely incident detection or traffic flow breakdown detection), but recognition of quantitative change rule of traffic flow was neglected in some degree. Based on the traffic flow theory and the elements of projective transform in descriptive geometry, the key to the changepoint recognition was analyzed by the complanation of dualistic linear regression. This method is calibrated and tested on the field data of a road to verify the validity and the feasibility of the theory.

Event-based merging of partial behavior models

Zhong-yu CHEN

2010, 30(1):  266-269. 

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System behaviors are described by modal transition systems. In allusion to unknown behaviors in partial behavior models, the authors formally defined model merging method based on event and refinement. Merging rules were defined based on refinement relation; with merging rules consistent models were merged for ruling out unknown behavior and resulted in a minimal common refinement or least common refinement. Finally, a case study illustrates the effectiveness of the method.

Speech spectrogram display in pseudo-color based on non-linear transform method

2010, 30(1):  270-273. 

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Concerning that the human eye to color resolution is much higher than grayscale difference, this paper proposed a new method to show the spectrogram by C# procedure, which focused on the mapping transformation function and built up the relationship between spectral magnitude and color, to make pseudo-color display come true, and also used it for speech spectrogram display and audio signal processing interface design. Meanwhile in order to achieve better analysis and learning effects, the authors added audio play function so as to watch the spectrogram while listening to the corresponding audio. This method, with simple programming, flexible interface design and less demand on the equipment, can be realized on ordinary PC.

Register based algorithm for VLIW DSP cluster assignment

2010, 30(1):  274-276. 

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Register is one of the most valuable resources. Software pipelining could bring about register pressure while scheduling instruction of VLIW DSP, which would cause register spill and software pipelining suspension. In the past research, instruction clustering pay more attension on instruction parallelism, and pass the register pressure to register allocator. In this paper, the authors clustered instruction through runtime inspection of the register command pressure. This is a dynamic method, according to all the pressure of each clusters register, which can reduce register spill and improve the efficiency of the program.

Design of USB multi-function data acquisition system based on MCF52223

2010, 30(1):  277-279. 

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With reference to the idea of USB OTG dual role, and based on the microcontroller MCF52223 which is integrated with USB2.0 module produced by Freescale Corporation, this paper put forward the concept of two-programmingmodels: "Self Data Acquisition" and "Non-self Data Acquisition"，realized the function of configurable embedded USB host, and completed the readwrite and inquiry of the U-disk, and made U-disk become the external mass storage devices and query database. This acquisition system stable usage in the meeting attendance system based on second-generation ID card shows that the design makes the data query, storage and read more convenient and can easily switch to nonself data acquisition mode, which can be referred by similar applications.

Research on short message system for information support equipment based on MC75

2010, 30(1):  280-281. 

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The short message platform based on SIEMENS MC75 module was designed as external extended function of the information support equipment. Connection was set up between MC75 module and the information support equipment by series port. Typical circuits were used by the module to connect SIM card and other peripherals. The short message sending mode and the process of platform working were introduced in the software description. The characteristics of short message platform were expounded in details. Sending and receiving short messages, detail settings and call connections were realized on the message platform with examples.

Duration model optimization in HMM-based TTS

2010, 30(1):  282-284. 

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Text-To-Speech (TTS) is one of the important technologies of humancomputer interaction. The current stateofart HMM based TTS can produce highly intelligible and natural output speech and deliver a decent segmental quality. However, its duration tends to be unnatural. In this paper, the state durations were generated by jointly maximizing the duration likelihoods of state, phone and syllable units. By considering the duration of state and longer units jointly, the accumulation of errors in estimated state durations was regulated in the optimization procedure. Experiments on Mandarin databases show that the optimized model yields more accurate duration predictions, compared with the baseline state duration model. The improvement of phone RMSE is 2.45ms. The perceptual test further confirms that the optimized duration model outperforms the baseline system.