05 July 2008, Volume 34 Issue 13
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Computer Engineering. 2008, 34(13): 1-3. https://doi.org/10.3969/j.issn.1000-3428.2008.13.001
Susceptibility Weighted Imaging(SWI) non-invasively displays the intracranial venous structure, which is significant in the clinical diagnosis of brain tumor, vascular malformation, and other central nervous diseases. This paper analyzes the unique image post-processing and reconstruction algorithm of SWI, and verifies its effectiveness through simulation images. This algorithm proves a better sensitivity to supratentonial venous and the lesion territory of tumor and vascular malformation compared with the traditional Magnetic Resonance Imaging(MRI) methods.
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Computer Engineering. 2008, 34(13): 4-6. https://doi.org/10.3969/j.issn.1000-3428.2008.13.002Location and routing of P2P node is currently a hot subject of research. If network churn is not very high, maintaining global lookup table at every node is reasonable. This paper presents Grouped Random Broadcast Messages(GBRM) algorithom for maintaining global lookup table to achieve one-hop lookup. Events are merged into notification message in the dispatcher node, and notification messages are sent to all nodes using a novel event dissemination algorithm. It shows that GBRM is able to achieve one-hop lookup, while using less bandwidth than other one-hop DHT algorithom, and it has high practical value.
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Computer Engineering. 2008, 34(13): 7-9. https://doi.org/10.3969/j.issn.1000-3428.2008.13.003Based on the analysis of the characteristics of polymorphic Shellcode’s behavior, an dynamic emulation based detection criterion is proposed. Using the criterion, this paper designs and implements a dynamic emulation based polymorphic Shellcode detection system, which is highly optimized in each module. With 3.3 GB real network data and 11 000 polymorphic Shellcode samples, the experiment on prototype presents zero false positive and false negative, and it improves the throughput of system.
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Computer Engineering. 2008, 34(13): 10-12. https://doi.org/10.3969/j.issn.1000-3428.2008.13.004According to the characteristics of Master Boot Record(MBR) in R*-tree, this paper creates the binary segment tree by sweeping the orthogonal overlapping region. Sweeping algorithm calculates the area and perimeter of the orthogonal overlapping region without changing the characteristics of the minimum bounding rectangle. Comparison of the evaluation reveals that the number of node access of R*-tree decreases by nearly 60 percent and the search accuracy increases by about 60 percent after calculating the overlapping compared with the algorithm uncalculated. Analysis and experimental results show that the algorithm can improve the accuracy and efficiency of route selection with inserting large amount of the spatial objects in approximate search by calculating the overlapping in advance.
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Computer Engineering. 2008, 34(13): 13-15,1. https://doi.org/10.3969/j.issn.1000-3428.2008.13.005To solve the problem of how to acquire local and all test case, ensur correctness and completeness of them, and insur their consistency with requirements, this paper presents the method by adopting advanced modeling technique to construct process model which can be simulated and validated, and applying slice technique to make and implement slice rules for the process model. The validity of the method is proved by induction based on process model structure. The paper also describes the algorithms for acquiring system test case based on slice rules, and introduces the component of the tool and an example in practice.
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Computer Engineering. 2008, 34(13): 16-18. https://doi.org/10.3969/j.issn.1000-3428.2008.13.006In order to better adapt user’s personalized demand and the characteristic of ubiquitous computing environment, a ubiquitous service framework based on context-aware is put forward. The framework consists of four layers: service presentation layer, service management layer, service provisioning layer and context-aware layer. It uses the service management method based service community to shield the distribution and heterogeneous of services in ubiquitous computing environment. It is aware of context information which is related to current computing environment and user’s activity. It utilizes service recommender mechanism based on context so that it can provide personalized service for users.
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Computer Engineering. 2008, 34(13): 19-20,2. https://doi.org/10.3969/j.issn.1000-3428.2008.13.007The quality of query results in the traditional FTP search engines is low because it is not optimized. To solve the problem, this paper builds a high performance and intelligentized FTP search engine——KFSE, based on the analysis of FTP user query logs. The double bytes inverted index, automatic classification of query results, and automatic rectify mistake for users are adopted in the system. Validity of the scheme is proved in the real system and it can improve the query efficiency and quality for the FTP search engine. The average of response time is lower than 500 ms and the precision is 92.5%.
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Computer Engineering. 2008, 34(13): 21-23. https://doi.org/10.3969/j.issn.1000-3428.2008.13.008Based on analyzing the relation of data points in time series, a novel series segmenting algorithm based on triangular midline is presented. During scanning these temporal data, this approach chooses three continuous data points in turn and calculates the triangle’s midline. According to these values and the user-defined distance threshold, this method records important turning points reflecting the sequence’s feature. Using these key points, the original time series is segmented and fitted linearly. Experimental results show that the new method is effective.
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Computer Engineering. 2008, 34(13): 24-25,2. https://doi.org/10.3969/j.issn.1000-3428.2008.13.009This paper presents a new method for Synthetic Aperture Radar(SAR) images feature extraction and target recognition using independent component analysis and support vector machine. Low-frequency sub-band image is obtained by wavelet decomposition of a SAR image. Independent Component Analysis(ICA) is used for extracting feature vectors from the low-frequency sub-band image as the feature of the target. Support Vector Machine(SVM) is used to perform target recognition. The method is used for recognizing three-class targets in MSTAR database and the recognition rate arrives at 96.92%. Experimental result shows that the method is an effective method for SAR images feature extraction and target recognition.
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Computer Engineering. 2008, 34(13): 26-28. https://doi.org/10.3969/j.issn.1000-3428.2008.13.010According to the requirement for adaptability in distributed embedded system such as UAVs, wireless sensor network and so on, some common methods are proposed to define similar nodes, compute their similarity degree, discover similar nodes and deploy the other’s tasks on them automatically. Based on the adaptive computing thoughts of “sensing evaluating adjusting sensing”, some reconfiguration ways for fault nodes and tasks are studied. The methods are more efficient to improve the adaptability of distributed embedded systems, in which some nodes are similar.
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Computer Engineering. 2008, 34(13): 29-30,3. https://doi.org/10.3969/j.issn.1000-3428.2008.13.011According to the requirements of huge customers and resource’s access policy diversification in distributed service environments and application limitation of access control models, this paper proposes an Attribute And Rule-based Access Control(ARBAC) model for multiple users service mode. It introduces notions of composite attribute expression and composite permission, defines different multiple role groups and makes a finite set of rules to assign user to roles. A case study is given and the model is compared with other models.
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Computer Engineering. 2008, 34(13): 31-33. https://doi.org/10.3969/j.issn.1000-3428.2008.13.012Deltoid is an efficient algorithms for finding significant changes among data streams, but its threshold setting methods increase memory usage and online operations. This paper proposes a new threshold setting method namely Deltoid Threshold Setting Using Hypothetic Traffic (DTSUHT) to solve such problems. Experiments on real network traffic show that Deltoid algorithm with DTSUHT achieves almost the same performance of existing threshold setting methods.
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Computer Engineering. 2008, 34(13): 34-36,3. https://doi.org/10.3969/j.issn.1000-3428.2008.13.013(Department of Computer Science and Engineering, Shanghai Normal University, Shanghai 200234)
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Computer Engineering. 2008, 34(13): 37-39. https://doi.org/10.3969/j.issn.1000-3428.2008.13.014Normally data cube is very large and relations among cells are very complicated. So semantic data cube is difficult to realize. Based on quotient cube, Semantic Data Cube(SDC) structure is put forward in this paper. Each cell in lattice expressed by its upper bound and low bound is also preserved. SDC depicts the lattice of cells concisely and stores data cube compactly and can keep all the semantic relations. The operators of drill-down and roll-up between cells can be done in SDC. Applying semantics to answer query and maintain incrementally, the cost of queries and updating can be reduced greatly. Experimental results show that SDC is effective.
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Computer Engineering. 2008, 34(13): 40-42. https://doi.org/10.3969/j.issn.1000-3428.2008.13.015Access Control is an important technology in system security, but it is new for collaborative design. This paper provides a new framework of multi-level access control based on hierarchical product modeling. A layered privilege model is developed to provide multi-granularity access permissions in the part level and feature level. It implements Role-Based Extended Hierarchy Access Control(RBEHAC) model, which is integrated with layered privilege model and common RBAC.
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Computer Engineering. 2008, 34(13): 43-45,4. https://doi.org/10.3969/j.issn.1000-3428.2008.13.016This paper proposes a new meta structure which makes C/C++ source codes with semantic tag. Using the meta structure with semantic configuration related to application, test tool can filter some semantic tags for instrument and so on. A dual parser engine is developed to create the structure, which avoids the complexity and indeterminacy of classic methods, and can support kinds of programming languages very well.
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Computer Engineering. 2008, 34(13): 46-48. https://doi.org/10.3969/j.issn.1000-3428.2008.13.017Most existing dynamic updating approaches can not recover the target application from some tainted states which are imported by the vulnerabilities. The lack of tainted states recovery can cause huge reliability disasters. This paper proposes to recover the tainted state during DSU based on the POLUS framework. Recovery solutions of deadlock, buffer overflow and data struct repair are presented and the experiments show that these approaches are viable.
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Computer Engineering. 2008, 34(13): 49-50,5. https://doi.org/10.3969/j.issn.1000-3428.2008.13.018Many researchers focus on the combination of ILP system together with the naive Bayesian classifier. And various Multi-Relational Naïve Bayesian Classifiers(MRNBC) have been proposed. This paper describes a methodology based on ILP for upgrading naïve Bayesian classifiers to first-order logic. There are almost relational databases everywhere in real-life, so this paper also aims at solving how to shape MRNBC based on relational databases theory. The upgrading can deal with data in multiple tables directly and transformation is not needed.
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Computer Engineering. 2008, 34(13): 51-53. https://doi.org/10.3969/j.issn.1000-3428.2008.13.019This paper proposes a novel rules-based model to extract data from Deep Web pages. The model comprises four layers, main processing parts as task allocation, information extraction, data cleaning which work based on the rules of structure, logic and application. It applies the new model to three intelligent system, scientific paper retrieval, electronic ticket ordering and resume searching. Experimental results show that the proposed method is robust and feasible.
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Computer Engineering. 2008, 34(13): 54-55,6. https://doi.org/10.3969/j.issn.1000-3428.2008.13.020Although WWW has provided much information for all fields, how to extract the authoritative information from related fields exactly is becoming a hot topic. This paper provides a process of extracting table data it provides a multiple factors assessment model to judge the Web page. Using the model, the authoritative value of Web page can be gained correctly. It provides a table-based phrase tree method to extract the interesting data automatically. Example proves that this method can extract the authoritative information exactly and automatically.
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Computer Engineering. 2008, 34(13): 56-57,6. https://doi.org/10.3969/j.issn.1000-3428.2008.13.021The research on association rules can establish the relationship of data containing missing value. While the integrity on filling the missing value is lacking. This paper proposes a rule recycle technique, which reuses the rules deleted in previous data mining by reclaiming and composing them in order to obtain more association rules. The recycle combined association rules can promote the filling rate and accuracy of missing values. And improves association rules mining algorithm which reduces the complexity of time and space.
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Computer Engineering. 2008, 34(13): 58-60. https://doi.org/10.3969/j.issn.1000-3428.2008.13.022Task scheduling in grid is an important research area at present. The processing performance and the stability of grid resources are both important factors related to propitious completion of task scheduling because of the characteristics of grid such as dynamicity and heterogeneity. For smaller completion time of tasks, a grid resource hypergraph model is proposed. Based on the model, resource clustering is carried on and a trustworthy task scheduling algorithm, GRHTS, is proposed. Simulation results show that grid resource hypergraph model based trustworthy task scheduling algorithm performs better than congener scheduling algorithms in grid and is an effect Grid task scheduling algorithm.
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Computer Engineering. 2008, 34(13): 61-63. https://doi.org/10.3969/j.issn.1000-3428.2008.13.023Most Web page classification methods are based on Vector Space Model(VSM), but it is not suitable for large scale application background with bad computation complexity. A new automated text classification method based on RSOM neural net tree and Bayes method is proposed, RSOM neural net tree is used in Web page index and Bayes method is used in automated Web page classification. The excellent performance of this method has been tested in feature dimension, performance, capacity and accuracy.
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Computer Engineering. 2008, 34(13): 64-66. https://doi.org/10.3969/j.issn.1000-3428.2008.13.024Effective data management is an important issue with more and more scientific applications manipulating massive distributed secondary-storage, this paper presents a novel application development architecture which includes a Meta Data Management System(MDMS) and Storage Systems(SS) that provide a platform for easy-to-use and automatic storage access optimizations. It adopts a novel multi-storage resource architecture that can satisfy both performance and storage capacity requirements, and employs an adaptive I/O optimization schemes.
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Computer Engineering. 2008, 34(13): 67-69. https://doi.org/10.3969/j.issn.1000-3428.2008.13.025In order to investigate the dynamic behaviors of basic events in fault trees, a new method based on Cut Sequence Set(CSS) is presented. Cut sequence includes a set of basic events that induce their top events, and the basic events in a cut sequence fail in a fixed order. CSS is the set of all cut sequences of a fault tree. The paper defines Sequential Failure Symbol(SFS) to describe the sequential failure of events. SFS is used to translate static gates and dynamic gates into Sequential Failure Expressions(SFE), which represents the sequential behaviors of the events in these gates. The failure of top event is described by some SFEs, namely cut sequences, which constitute CSS. A CSS generation algorithm is put forward, and an example illustrates the application and advantages of the method. The approach represents system failure behaviors by using a sequence with some components, which provides a new qualitative analysis approach to study fault trees.
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Computer Engineering. 2008, 34(13): 70-71,7. https://doi.org/10.3969/j.issn.1000-3428.2008.13.026To avoid the blindness of data backup system construction, this paper researches the key parameters of storage capacity, backup window, read and write performance, etc, depending on system running characteristic before putting it into execution. From the simple and perfect system architecture, it builds the mathematical models, analyses quantitatively by instances, and takes enough account of the effects of network, operating system, mechanical devices, accidents, etc, adds the proper repair parameter depending on the actual cases, and tries to estimate the practical parameters to serve system design and strategy optimization.
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Computer Engineering. 2008, 34(13): 72-74. https://doi.org/10.3969/j.issn.1000-3428.2008.13.027JPF is a Java program model checker developed by NASA. The module that generates the state space in JPF is rewritten to make the program waiting for model checking run under supervision. The Data-Race algorithm is applied to record warnings which guide JPF to check deadlock related threads. This design avoids the state space explosion and realizes model checking of large-scale programs with only some threads in deadlocks. A heuristic method is also proposed to optimize the efficiency of simulation running by giving different weights to live threads according to search depths.
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Computer Engineering. 2008, 34(13): 75-77. https://doi.org/10.3969/j.issn.1000-3428.2008.13.028A multi-cluster computing model is introduced. In the analysis on the basis of the multi-cluster system features, which include flexible architecture and reconfigurability, the methods and technologies of performance monitoring and analysis, which is applicable to this model, are researched. A performance monitoring and analysis tool of parallel jobs is designed and implemented. In this tool, dynamic performance analysis method is used, distributed software design framework is followed, a high cohesion and low coupling structure is designed. Operation results show it can work effectively in the multi-cluster computing model.
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Computer Engineering. 2008, 34(13): 78-80,1. https://doi.org/10.3969/j.issn.1000-3428.2008.13.029An Implementation of incremental Web Crawler that supports update of search engine over millions of Web pages on daily basis is introduced. With analysis on the weakness of traditional periodic Crawler and difficulties in incremental Web Crawler, this paper presents key strategies on prediction of Web evolution, algorithms of locating changed Web pages based on MD5, URL scheduling and caching, describes the implementation, and evaluates the Crawler system. The incremental crawler has been integrated with TianWang search engine at Peking University for 6 months. Update cycle is reduced by 20 days, accuracy of evolution prediction reaches 79.4%, and real-time efficiency, extendibility and stability are improved.
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Computer Engineering. 2008, 34(13): 81-83,1. https://doi.org/10.3969/j.issn.1000-3428.2008.13.030The radio model in OPNET is not suitable for multi-channel scenarios. It can not give physical carrier-sensing state correctly while channel is switching. The problems which forbid multi-channel simulations in OPNET are analyzed. A new radio model which supports the transceivers of a node to switch between multiple channels is also proposed. And the radio model with the multi-channel MAC protocol simulations in wireless Ad Hoc network scenarios is certified.
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Computer Engineering. 2008, 34(13): 84-86. https://doi.org/10.3969/j.issn.1000-3428.2008.13.031Based on the speaker recognition system, the linear and nonlinear influences of carbon-button telephone channel are discussed. A compensation system is proposed to weaken those effects. By researching the frequency difference between telephone channel and traditional channel, the phantom formants are found, which can be reduced by normalization of its residues. Combined with CMS and ceptral lifter, the system is more robust under mismatch environment.
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Computer Engineering. 2008, 34(13): 87-88,9. https://doi.org/10.3969/j.issn.1000-3428.2008.13.032Within data grid environments, dynamic replication is a general mechanism to improve performance and availability for distributed applications. As the experimentally efficient strategies are based on single-location algorithms, they are not suitable for geographically broad grids with long latency. To address such issues, three multiple-location strategies are proposed, which are converted into classical mathematic problems that can be solved by some famous approximation algorithms. The strategies are suitable for resource management in the remote education.
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Computer Engineering. 2008, 34(13): 89-91. https://doi.org/10.3969/j.issn.1000-3428.2008.13.033Self-localization of nodes is one of the key technologies for application of Wireless Sensor Network(WSN). By analyzing the model of waves propagation in outdoor, this paper provides a weighted centroid localization algorithm. Combined with the rules of selecting fine nodes, it uses weight coefficient to evaluate position accuracy of nodes. This algorithm is simple and no communication is needed while locating and its location accuracy is higher than maximum likelihood estimation. The simulation using Matlab shows that this algorithm basically meets the application’s need.
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Computer Engineering. 2008, 34(13): 92-94. https://doi.org/10.3969/j.issn.1000-3428.2008.13.034As the development of the multi-media applications, it is considered to provide one kind of high rate and digital schema among stateless core nodes. The congestion control scheme is completed by edges nodes. A scheduling algorithm of stateless core nodes based on cost is proposed, and the simulation analysis is given according to this algorithm. Test result shows that the cost would be nearly linear with the service performance provided in the network.
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Computer Engineering. 2008, 34(13): 95-97. https://doi.org/10.3969/j.issn.1000-3428.2008.13.035RFC2544 is an international standard to test network interconnect devices. This paper describes the design and realization of a benchmark test for the network tester with the high-performance and low-price. This paper introduces the RFC2544 relevant standard and testing condition. And the paper also describes the network tester working principle by introducing the design of the system’s hardware and software architecture. With the relevant test conditions, in contrast to other network testers based on RFC2544 bidirectional test, it is confirmed to be precise for the system based on the quantization error of the experimental results.
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Computer Engineering. 2008, 34(13): 98-100. https://doi.org/10.3969/j.issn.1000-3428.2008.13.036The scalability of multicast is a problem of multicast technology. A method of resolving the scalability problem——aggregated multicast and the group-tree matching algorithm are analyzed. A dynamic match algorithm——Fast Dynamic Matching Algorithm(FDMA) is proposed. FDMA algorithm can raise the aggregating speed. And by the management of aggregated trees, it can decrease matching times. In the simulations, the group-tree matching times decrease by over 80%. So the real-time property is improved greatly.
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Computer Engineering. 2008, 34(13): 101-103. https://doi.org/10.3969/j.issn.1000-3428.2008.13.037Based on the NetFlow technology, this paper submits a visible flow geometric model in space of three dimensions by using some characters of campus network’s boundary traffic. Those characters include IP, port, protocol and volume of flow. This model simplifies display of network’s traffic. An algorithm of A-based alterable coordinates modeling is designed to optimize model rendering. The model and algorithm provides a method for network manager to apperceive network performance by 3D visible graph of flow. Experiment shows that the model effectively reflects relevant characteristics of traffic.
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Computer Engineering. 2008, 34(13): 104-106. https://doi.org/10.3969/j.issn.1000-3428.2008.13.038Test cases and test platform are designed for conformance testing of 6LoWPAN adaptation layer protocol. Based on analyses of 6LoWPAN adaptation layer protocol, test purposes are grouped and created. Nearly 100 test cases are designed for these test purposes. To conduct test cases, a test platform is developed to send stimuli and observe the behavior of the system under test. The conformability of the adaptation layer implementation is achieved by using more than 90 of these test cases.
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Computer Engineering. 2008, 34(13): 107-109. https://doi.org/10.3969/j.issn.1000-3428.2008.13.039In the traditional AODV, when the link occurres the accidental broken, single link repair method will affect overall network performance. According to this problem, the article presents a method that combines the source node repair and local node repair, and results show that the improved AODV is superior to the traditional AODV by simulation data.
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Computer Engineering. 2008, 34(13): 110-112. https://doi.org/10.3969/j.issn.1000-3428.2008.13.040Peer-to-peer overlay route model is able to query accurately, but does not sustain semantic query. This paper clusters nodes according to their data interests by forming semantic space, and designs an improved semantic peer-to-peer route model to enhance file query efficiency. Simulating experimental results show that the improved model has better performance.
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Computer Engineering. 2008, 34(13): 113-114,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.041The AES software implementes in the way of looking up tables, while the indices affect the Cache hit and miss, and then the time of the AES encryption, however, the indices have a close connection with the secret key. After analyzing the relationship between the indices, and the ciphertext, and final round sub key in the AES final round encryption, it proposes a novel attack against AES by using the Cache hit information, and validates its feasibility with experiments on Intel Celeron 1.99 GHz and Pentium4 3.6 GHz CPU, recovers the 128 bit AES key in 221 and 225 random plaintexts in 5 min separately, and introduces several countermeasures for protecting the AES.
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Computer Engineering. 2008, 34(13): 115-117,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.042This paper presents a new approach to automatic construction and optimization of the Network Attack Graph(NAG). For solving scalability problem of the NAG, a hierarchy has been adapted for the network structure that can be divided into attack subgraph and attack supergraph. The attack subgraph describes concrete attack scenarios from the source host to the destination host. The attack supergraph described the attacker’s privilege transition processing. This approach reduces the complexity of NAG by simplifying the structure of it.
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Computer Engineering. 2008, 34(13): 118-120. https://doi.org/10.3969/j.issn.1000-3428.2008.13.043According to the requirement of Distributed Denial of Service(DDoS) testing and evaluation, this paper presents the design and implementation of a DDoS attack-defense testbed. This testbed uses real machines to emulate network. It provides background and DDoS attack traffic generation, network topology configuration, data acquisition, evaluation and display ability, and has a configuration and control interface based on Web. Experimental results show that this testbed provides a convenient testing and evaluation environment for DDoS attack- defense systems.
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Computer Engineering. 2008, 34(13): 121-123. https://doi.org/10.3969/j.issn.1000-3428.2008.13.044Brute force attack on block cipher algorithm is an important direction of cryptology. Software of brute force attack on block cipher algorithms is designed based on distributed computing. Brute force attack on block cipher algorithms DES and SMS4 are simulized in the LAN and the function test to the software is carried on. It analyzes the software and results of brute force attack on DES and SMS4. Experimental results show that this software has strong commonability.
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Computer Engineering. 2008, 34(13): 124-126. https://doi.org/10.3969/j.issn.1000-3428.2008.13.045According to the existing signature extraction algorithm which considers the known character, this paper proposes a signature extraction algorithm based on known characteristic and environment dependent variable. This algorithm can improve the extracting speed by using the known character while searching the frequent items. The environment independent variable makes the signature more accurate. The experimental results show that this algorithm can extract the signature more quickly and more accurately than the Signature Apriori algorithm.
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Computer Engineering. 2008, 34(13): 127-129. https://doi.org/10.3969/j.issn.1000-3428.2008.13.046Based on analysis of MPPR algorithm, this paper presents the architecture of a special computing system for solving ECDLP, and discusses the components, realization and the computing processes of the system. Then the formulas of the system for the capability of executing MPPR and the time for solving an ECDLP are given. On this basis, the security strength of a cryptosystem based on ECCp-112 is insightfully analyzed under today’s scientific technique conditions.
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Computer Engineering. 2008, 34(13): 130-132. https://doi.org/10.3969/j.issn.1000-3428.2008.13.047Digital proxy multi-signature scheme and blind signature are very suitable for electronic commerce and payment. Based on the Schnorr signature and Chaum blind signature scheme, this paper presents an efficient proxy blind multi-signature scheme, which satisfies the security properties of both the blind signature scheme and the proxy multi-signature scheme. This scheme has advantages such as the low computation load, high efficiency and security, and the length of signature does not increase when the new original signers join in. It is very important in an electronic cash and electronic vote system.
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Computer Engineering. 2008, 34(13): 133-135. https://doi.org/10.3969/j.issn.1000-3428.2008.13.048Through studying the ARP-spoofing which is one of the most dangers in the Intranet, based on the ARP-cache-overtime mechanism, this paper proposes a method to detect Man-In-The-Middle(MITM) attack in the switch network, investigates ARP-cache-overtime mechanism based on Windows, presents a method to detect and calculates the overtime. Experimental results show that when host receives an ARP packet, the ARP cache item is updated. Before this item is overtime, the host can not send ARP request packet to the item. Therefore, in this period the host does not receive any ARP reply packet related to this item. If the ARP packet statistic is not agreed with the principle, ARP-spoofing happens.
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Computer Engineering. 2008, 34(13): 136-138. https://doi.org/10.3969/j.issn.1000-3428.2008.13.049Combining the human visual system with the image local properties, this paper proposes a watermarking algorithm based on wavelet transform and Fuzzy C-Mean(FCM) clustering. Watermarking embedding locations are identified adaptively on the wavelet domain coefficient of the B channel by applying FCM clustering algorithm based on the human visual system. And the watermarking is embedded adaptively according to the image local correlation and cluster result. The watermarking can be extracted without the help from the original image. Experimental results show that the watermarking scheme is invisible and robust against various signal processing such as JPEG compression, image enhancement, cropping, noise adding and filtering.
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Computer Engineering. 2008, 34(13): 139-141. https://doi.org/10.3969/j.issn.1000-3428.2008.13.050In order to hide the site of real hosts in network topology map, and to decrease the possibility of the real host to be attacked, this paper presents a network topology camouflaging model that the real hosts and pseudo hosts configure alternatively, describes network topology camouflaging model: all hosts (include real hosts and pseudo hosts) have the different action according to their roles and features, and are connected with neighbors based on network topology camouflaging map, amd proposes the algorithms for active camouflaging process and passive camouflaging process. Experimental results show that the model is effective and efficient, and hides the real host very well.
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Computer Engineering. 2008, 34(13): 142-143,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.051This paper presents a scheme of digital fingerprint in the statistical invariable characteristic of wavelet domain. Initial values of chaotic mapping are created by user information. User fingerprint is created with those values by chaotic method and coded by error-correcting coding. Audio signal is divided into frames. Use Hamming window in every frame and deal the audio frames with DWT and embed the fingerprint into each frame according to statistical invariable characteristic of wavelet coefficients. Inverse transform of audio frames are made and combined into audio signal with fingerprint. Experimental results show that the scheme is robust, it can resist common audio attacks and methods, and it is insensible to synchronization attack, so it can protect copyright. At the same time, it can apply in the confirmation of traitor because digital fingerprint has characteristics of anti-collusion.
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Computer Engineering. 2008, 34(13): 144-146. https://doi.org/10.3969/j.issn.1000-3428.2008.13.052Blu-ray disc and HD DVD use Advanced Access Content System(AACS) to protect the media content. This paper analyzes the AACS, and finds the software decryption has many problems. It proposes Security Management System(SMS) which uses the Advanced Encryption Standard(AES) algorithm for decryption and encryption. It is implemented by hardware. It can avoid many problems which implement in software. The SMS takes some special measures to protect the AES keys which are deposited in the device.
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Computer Engineering. 2008, 34(13): 147-148,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.053Time-stamping provides accurate time for E-document or E-transaction to prove. This paper analyzes the present scheme based on relative temporal authentication and absolute temporal authentication. A new scheme for secure digital time-stamping is proposed based on Elliptic Curve Cryptography(ECC) blind signature, which can effectively prevent the forward forgery, and prevent the backword forgery which is caused by signaturer and TSS ploting.
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Computer Engineering. 2008, 34(13): 149-151. https://doi.org/10.3969/j.issn.1000-3428.2008.13.054This paper proposes a formal model based on state transition system. Dolev-Yao intruder model are assumed, and based on state transition system, message and event are semantically encoded, protocol rule are defined by rewrite relation, and security properties are descripted by event set. It proposes inspection strategy for security properties. The model can give accurate formal specifications for security protocols, and is easy to realize automatic analysis.
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Computer Engineering. 2008, 34(13): 152-153. https://doi.org/10.3969/j.issn.1000-3428.2008.13.055This paper proposes a public key traitor tracing scheme based on RSA. In this scheme, broadcaster can not frame innocent users and the traitors can be traced by black-box tracing. The tracing algorithm is deterministic and it works without the limitation of the number of traitors. The scheme deals with stateless receivers. When traitors are found, the broadcaster can revoke them without involvement of the remaindering receirvers.
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Computer Engineering. 2008, 34(13): 154-156. https://doi.org/10.3969/j.issn.1000-3428.2008.13.056Aiming at the security problems in the International Card Acquiring System (ICAS) and EMV migration, this paper introduces the key management system, certification process and encryption mechanisms for ICAS, and proposes an applicable security enhancement solution to ICAS. The architecture, software and hardware and operation of the solution are described. Both theoretical and experimental results show that the solution has higher security and significant improvement on anti-attacks and threat reduction in bank information system.
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Computer Engineering. 2008, 34(13): 157-159. https://doi.org/10.3969/j.issn.1000-3428.2008.13.057This paper presents design of authorization management based on Web2.0, and puts forward a type of extended role-based access control Model which is focus on user personality page and multilevel-users management. It is successful used in the authorization management on Web2.0.
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Computer Engineering. 2008, 34(13): 160-162. https://doi.org/10.3969/j.issn.1000-3428.2008.13.058According to the security problems in network commerce, a trusted center architecture based on intrusion tolerance and its algorithm of hybrid encryption are designed with identity-based cryptography. A scheme of identity-based security collaborative commerce platform is proposed based on that. The scheme has better performance compared with the traditional ones based on certificate. Analysis indicates that the scheme is secure, efficient and suitable for networked manufacturing.
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Computer Engineering. 2008, 34(13): 163-165. https://doi.org/10.3969/j.issn.1000-3428.2008.13.059For the GSM security mechanisms can not achieve end-to-end secure communications, this paper presents a novel voice encryption algorithm, which can penetrate RPE-LTP coding Vocoder. The encryption algorithm does not destroy voice features, has anti-RPE-LTP coding features, and can realize the end-to-end secure communications in the GSM voice channel. It can receive good encryption effects when the algorithm parameter is among 20 and 25, and it can get good distortion on time domain and frequency domain when the parameter is 20.
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Computer Engineering. 2008, 34(13): 166-168,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.060This paper puts forward a Network Intrusion Detection System(NIDS) based on coarse-grained model genetic algorithm, after analysing the application of genetic algorithm in intrusion detection system. By analysing the protocol’s property, finds out some characteristics which are often lawlessly changed and used, forms the original chromosome by assembling and coding, makes all processor(terminal points)carry genetic process by attributed manner, makes the evolution of chromosomes prosecute in all detection points simultaneity, and all processor can intercommunacate by transplanting too. At the same time, redesign a reasonable fitness function, to let the use of “gene” be more reasonable. Experimental data shows the system’s detection ability is above 90%.
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Computer Engineering. 2008, 34(13): 169-171. https://doi.org/10.3969/j.issn.1000-3428.2008.13.061Different subjective attitudes play a role in preference to difference policies on actions. However, Agent individuality is hard to embody in quantitative or symbolic value-based decision models. Based on current utility maximization decision models, this paper obtains policy conforming to Agent individuality by associating individual decision principle with certain Agent individuality, referring to qualitative decision theory. Decisions reflect Agents’ varieties of personalities, and individualizing diversifies Agents’ behaviors, which helps modeling of Agent society.
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Computer Engineering. 2008, 34(13): 172-173,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.062Support Vector Machine(SVM) is a new technique for data mining. It has wide applications in various fields and is a research hot pot of the machine learning field. Due to its differentiability, smooth SVM, a reformulation of standard SVM, has shown advantages in many aspects. This paper introduces the basic principle of smooth SVM, SSVM model, PSSVM model and a new class of smoothing functions, it focuses on the open and key problems in this field. It discusses some promising directions of smooth SVM research for future work.
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Computer Engineering. 2008, 34(13): 174-176,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.063This paper redefines the conception of “round” on the basis of Low Energy Adaptive Clustering Hierarchy(LEACH) for wireless sensor networks, and partitions a round into three phases, instead of traditional two phases. A new algorithm named Ant Colony-based Double Cluster-Heads Algorithm(ACDCHA) is proposed through introducing the idea of ant colony algorithm. A master cluster head and a vice cluster head are selected in each cluster according to the pheromone concentration, tasks such as data collection, fusion, transition, etc. are allocated respectively to these two kinds of cluster head. Simulation results show that, compared with LEACH and LEACH-C, the algorithm can get a better balance of the energy dissipation and prolong the network lifetime.
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Computer Engineering. 2008, 34(13): 177-179. https://doi.org/10.3969/j.issn.1000-3428.2008.13.064This paper proposes a novel method of SIFT-based feature matching of three-view image. SIFT based feature matching algorithm is used in three-view images matching process. Then the trilinear constraint and trifocal-tensor-based pixel transfer error computation method is introduced to remove the outliers produced by the SIFT algorithm. Experiments are carried out on the real three-view images, and the result shows that the algorithm highly improves the veracity of three-view images matching, with 97 percent of the outliers eliminated.
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Computer Engineering. 2008, 34(13): 180-181,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.065This paper analyses the real undersea environment effects on Autonomous Underwater Vehicle(AUV) and presents a local planning architecture based on Fuzzy Logic(FL). The key feature of the approach is integrated with the states of AUV, the environment of path and the object. The result of planning is a velocity factor, which can be taken into account by local path planning solution. Experiments show that the method is helpful and reliable especially to long distance and big-scale voyage of AUV.
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Computer Engineering. 2008, 34(13): 182-184. https://doi.org/10.3969/j.issn.1000-3428.2008.13.066To solve the problem that it is difficult to directly detect the object in the water for flares and cloud shadows, this paper proposes a water wake recognition method based on directional Fourier power spectrum and Support Vector Machines (SVM). This algorithm divides the whole image into sub-images with the same size, improves the traditional principal components analysis to obtain the sub-image direction from their Fourier power spectrum, partitions the power spectrum into 20 region, gets texture features from calculating the sum of every region, which are translation invariant and rotation invariant, and SVM is used as the classifier. Experimental results prove that the proposed algorithm can fetch the wake texture precisely.
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Computer Engineering. 2008, 34(13): 185-187. https://doi.org/10.3969/j.issn.1000-3428.2008.13.067This paper presents an algorithm regarding word group as a special symbol to detect video text automatically. It extracts an 18 dimension features vector according to strokes feature and two-dimension layout feature of video text, and uses a pre-trained Support Vector Machine(SVM) to partition frame regions into text and non-text regions. A multi-resolution model is used to detect texts of different font sizes, and a dilatation-shrink process is employed to adjust the text position. Experimental result shows that the detection rate of the method achieves 93.17% and the false detection is 0.73%.
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Computer Engineering. 2008, 34(13): 188-189,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.068This paper analyses the theory and effects of Total Variation(TV) model for noise removal and proposes a new fourth-order Partial Differential Equations(PDE) de-nosing model to avoid the blocky effects of second-order PDE model, while preserving edges. A symmetric discrete algorithm based on four-neighbor system is developed to solve the new model. Median filtering is applied to alleviate the speckle effects in the processed image at last. Experimental results show that the new algorithm is better, compared with traditional methods.
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Computer Engineering. 2008, 34(13): 190-192. https://doi.org/10.3969/j.issn.1000-3428.2008.13.069This paper presents an approach for Hidden Markov Model(HMM) training based on Particle Swarm Optimization(PSO). HMM parameter adjustment rules are induced by using PSO and Quantum-behaved Particle Swarm Optimization(QPSO) separately. Discriminative information contained in the training data is used to improve the performance on HMM effectively and the method is used in facial expression recognition. Facial expression feature vectors are extracted by using Discrete Cosine Transform(DCT). Experimental results show that the new method provides satisfactory recognition performance and is powerful for HMM parameter estimation.
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Solution of Hard Constrained Optimization Problem Based on Modified Differential Evolution AlgorithmComputer Engineering. 2008, 34(13): 193-194,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.070For solving hard Constrained Optimization Problem(COP), this paper proposes a new method named Simple Penalty Function Method (SPFM) based on properties of exponent function. SPFM avoids the difficulty of choosing the penalty factors. Modified Differential Evolution algorithm(MDE) is advanced, which combines SPFM with Differential Evolution(DE). By using MDE to solve Bump problem, more better optimization solutions gained by MDE shows that MDE is effective.
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Computer Engineering. 2008, 34(13): 195-197. https://doi.org/10.3969/j.issn.1000-3428.2008.13.071For the randomness, fuzziness and incompleteness in the of system dynamic information, a fuzzy logic diagnosis model to the crops diseases and insect pests is built using the logic reasoning method in mathematical theory, and an algorithm is given to the known symptoms. Simulation example SHOES, the fuzzy logic algorithm can effectively complete the diagnosis on insect pests with the lack of many factors, symptoms and complete information, which is intelligent, simple and practical.
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Computer Engineering. 2008, 34(13): 198-199,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.072This paper presents an improved background generation algorithm based on sequence image. On the foundation of building the Gaussian mixture model, the algorithm categories the Gaussian distributions which correspond to a pixel into reliable distributions and unreliable distributions that can evolve into reliable distributions by accumulating pixel values. When a new image comes up, the algorithm will create a new distribution, update an existed distribution or remove an obsolete distribution according to a specified pixel of the current image, and update the background image at the same time, to get a real-time background without moving targets. A quantitative analysis is given to the experimental data, result proves the adaptation and stability of the proposed algorithm.
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Computer Engineering. 2008, 34(13): 200-203. https://doi.org/10.3969/j.issn.1000-3428.2008.13.073This paper proposes an improved adaptive colony optimization algorithm and mainly presents a parameter of global best tour in strategies of pheromone updating to discusses QoS multicast routing problem with multiple constrains. The dynamic pheromone updating is adopted to ensure that global searching and convergence abilities are improved adaptively and avoid falling in local peak. Simulation results demonstrate that the proposed algorithm performs better than the combination of ant colony algorithm and genetic algorithm for solving QoS multicast routing problem with multiple constrains.
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Computer Engineering. 2008, 34(13): 204-206. https://doi.org/10.3969/j.issn.1000-3428.2008.13.074A hybrid genetic algorithm is proposed to search the optimal solution of mobile agent multi-task matching and scheduling problem. The problem model and chromosome representation are defined. The initial population is generated by the taboo search and random selecting method. And a new crossover mechanism is designed to make the new scheduling evolved by crossover mechanism valid. To accelerate the algorithm convergence, taboo search and tasks load mutation operator is adopted. Also the best chromosome preserving strategy is adopted to keep optimal solution non-decreasing performance. Simulation results of 18 graphs combined by 2 kinds of task nodes, 3 kinds of communication costs and 3 kinds of host nodes show that the algorithm can get 37.1% improvement compared with standard genetic algorithm.
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Computer Engineering. 2008, 34(13): 207-209. https://doi.org/10.3969/j.issn.1000-3428.2008.13.075Based on fast interger pixel block motion estimation algorithm and its improvement algorithms in H.264, this paper proposes a new Fast Adaptive Multi-Rings Search algorithm(FAMRS). The adaptive multi-rings search rings are made from the motion vector which is gained from motion estimation modes, combining with the small hexagon pattern in center. Experimental results show that the efficiency of this optimized algorithm outperforms UMHexagonS algorithm in H.264.
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Computer Engineering. 2008, 34(13): 210-213. https://doi.org/10.3969/j.issn.1000-3428.2008.13.076As the demand of multimedia value-added services becomes larger than ever before, the capacity of media resource server becomes the bottleneck of the development of these services. In this paper, a heterogeneous multi-core processor based media resource server solution is proposed based on the analysis of characteristics of media resource servers. The paper focuses on the architecture of the server and optimizing of media process under the heterogeneous multi-core architecture. Simulation test shows that the media resource server can get 2~4 times performance boost than previous solution.
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Computer Engineering. 2008, 34(13): 214-217. https://doi.org/10.3969/j.issn.1000-3428.2008.13.077This paper analyzes the issues in the application development of multimedia for digital home. A new middleware is raised which is based on CORBA Component Model(CCM) and named as Digital Home Multimedia Middleware(DHMM). DHMM can finely support the transmission, management, synchronization, storage and playback among the devices in digital home, thereby simplifying the development of high-level application and increasing the development productivity. The application in example system verifies the feasibility and validity of the framework.
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Computer Engineering. 2008, 34(13): 218-220. https://doi.org/10.3969/j.issn.1000-3428.2008.13.078For directly showing the preferable performance figure of Ultra-Wideband(UWB) communication, a scheme of embedded video demonstration system of UWB communication is presented. An embedded Linux system based on microprocessor of Samsung S3C2410 is applied to image collection in UWB transmitter, and video is captured with the VFW component provided by Microsoft Windows in UWB receiver. It is proved that the design of hardware and software achieves the anticipated results.
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Computer Engineering. 2008, 34(13): 221-223,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.079Aiming at assistant decision-making for DRP systems, composite prediction based on gray forecasting and brown single parameter exponential smoothing method is brought forward, which predicts the development of the future with the use of analysis to the old data. At the same time, aiming at safe problems and systematic integration, the schemes of double authentications and two-layer integration are put forward. The schemes can help enterprise assistant decision-making and flow optimization combing with the frondose application of enterprise so as to prove the validity of research.
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Computer Engineering. 2008, 34(13): 224-226. https://doi.org/10.3969/j.issn.1000-3428.2008.13.080This paper discusses color-based image retrieval technique in the Lab color space. It analyzes the shortcoming of existing algorithm based on Lab hue histogram, presents an improved retrieval algorithm based on chromaticity coordinate of Lab space. A uniform quantization of chromaticity coordinates(a, b) down to twenty-two bins is performed, their histograms can describle the color context of the image, and preserves the chromaticity coordinates’ characteristic. This paper implements the relevant feedback technique with piece-of-interest. Experimental results show that the improved method has sound and robust retrieval performance, and the relevant feedback technique also enhances the retrieval effectiveness.
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Computer Engineering. 2008, 34(13): 227-228,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.081This paper introduces the characteristic of Automatic Fare Collection(AFC) station equipment in urban railway traffic, analyses the requirement of the Ticket Vending Machine(TVM), and introduces the current design method and the limitation of software. According to the shortcomings, this paper introduces an embedded operating system named ReWorks, presents a blue print designing and developes the software of TVM in urban railway traffic based on ReWorks.
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Computer Engineering. 2008, 34(13): 229-231,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.082By building the environment of the protocol analysis, this paper analyses the protocol of the Fetion Instant Messenger(IM) of China Mobile and summarizes the protocol formats of the text information and file transmission. Based on the protocol analysis, it designs and implements the monitoring system of the Fetion IM of China Mobile with Network Driver Interface Specification(NDIS) technology, which can supervise the text information and file transmission effectively and intercept the deleterious information in real time.
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Computer Engineering. 2008, 34(13): 232-233. https://doi.org/10.3969/j.issn.1000-3428.2008.13.083In order to solve the problem of wireless image data transmission in image supervisory system, a method adopting GPRS to achieve TCP/IP connection is put forward to transmit image data. The plan can realize and set up TCP/IP connection, thus can carry on wireless image data transmission, in which the hardware adopts AT91SAM9260 processor and Q2403 GSM/GPRS module, the software adopts Uip1.0 TCP/IP protocol stack.
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Computer Engineering. 2008, 34(13): 234-235,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.084This artical introduces the design of networked auto sensor based on the structure of automotive full CAN network. The design of overall framework and basic structure are presented. CAN network interface of automotive sensor is also discussed. Combined with specific hardware structure diagram and circuit diagram, the realization of interface software is described. The data of the system can be transmitted to the bus of automotive CAN accurately.
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Computer Engineering. 2008, 34(13): 236-238. https://doi.org/10.3969/j.issn.1000-3428.2008.13.085The control system of clothing hanging pipeline based on CAN bus is designed and realized. The system overall structure, software and hardware composition, realization of CAN communication are depicted. The communication between 33 nodes, each node and PC, the pipeline control, the PC’s monitor management to nodes are realized in the system. The practical application indicates that, the system can run reliably and easy to be operated, as well as satisfy user’s requirements.
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Computer Engineering. 2008, 34(13): 239-241. https://doi.org/10.3969/j.issn.1000-3428.2008.13.086Flight control system is one of the important airborne equipments and ensures the flight safety and quality. According to test requirements of a flight control system, an Automatic Testing System(ATS) is designed based on PXI bus and GPIB bus. Hardware is integrated according to requirements of test signals. Software is also designed in term of the modularization, hiberarchy, and standardization. The ATS has characteristics of the generalization and extension. Experiments show that the developed ATS meets requirements of the flight control system and improves the test efficiency.
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Computer Engineering. 2008, 34(13): 242-244. https://doi.org/10.3969/j.issn.1000-3428.2008.13.087To achieve intelligent management of configuration-errors and improve the efficiency of router configuration management, the following works are done: propose a segmentation algorithm to divide the router configuration-text by function, study the configuration-strategy extraction technology from each segment, construct a reasoning-machine-model, which is used to extract the configuration-strategy from each segment based on certainty-method. The recent experimental results show that both text-division and strategy-extraction have an over 94% accuracy rate, which makes a good technical preparation for building an intelligent management system on configuration-errors of router.
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Computer Engineering. 2008, 34(13): 245-247. https://doi.org/10.3969/j.issn.1000-3428.2008.13.088The paper presents the architecture of Spatial Information Grid(SIG). Based on this, it designs the grid management and service system of multi-frame in city and describes the key techniques of system. According to analyzing an instance of city management case, it validates that the system can satisfy the requirements of combining distributed various data resource and handling cases by cooperating with many departments. So it is promising and can be popularized.
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Computer Engineering. 2008, 34(13): 248-250. https://doi.org/10.3969/j.issn.1000-3428.2008.13.089This paper proposes and implements a methodology for developing WebGIS. Key elements of the methodology include establishment of the self-defined protocol working on application layer of TCP/IP model, implementing communication between client and server based on the self-defined protocol by utlizing Winsock programming and realizing spatial data access interface based on COMGIS development. Based on these technologies, a WebGIS with C/S structure is implemented, andthe feasibility of the methodology is validated.
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Computer Engineering. 2008, 34(13): 251-252,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.090A real-time large scale deformation for the 3D geometry model of the knee joint is required in the virtual knee joint surgery. The quality of the deformation, including the outline, the detail, the degree of smoothness, the topological characteristics and so on, has an evidence effect on reality. Towards the 3D model of the knee joint, a new deformation method is established. It can perform deformation by building the skeleton of the model based on the cross section of the mesh, and using the transformation of the cylindrical coordinates. The geometry character of the model is correctly preserved. This method can satisfy the demand of real-time and reality in the virtual surgery. This method can also be applied to other bend deformations on joints.
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Computer Engineering. 2008, 34(13): 253-255. https://doi.org/10.3969/j.issn.1000-3428.2008.13.091Vehicle monitor is difficult to monitor vehicle runing in continuous Tri-dimensional Traffic Area(TTA). This paper proposes a vehicle monitor framework, which integrates X3D, XML with GPS, and it realizes vehicle movement model, to locate exactly where the cars run in, and to watch cars run in TTA. The framework is proved to be feasible by test done in Guangzhou, which can also be applied in traffic simulation and vehicle behavior analysis.
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Computer Engineering. 2008, 34(13): 256-258,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.092Realistic human modeling is one major part in the field of virtual human research. In this paper, a method of model-based human body fast modeling is presented. The skin layer of human geometric model is constructed by Polygon mesh surfaces and the skeleton layer according with H-Anim standard. Aiming at lack of joints center position data in model files exported by Poser software, an approach of extracting human body skeleton is given. With the skin layer deformation driven by the movement of skeleton, human body dynamic model is built by using the kinematics theory of robotics. Skeleton extraction results with various postures and simulation of arm motion for salute action are achieved on the platform of VC++, which show the method presented is effective.
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Computer Engineering. 2008, 34(13): 259-261. https://doi.org/10.3969/j.issn.1000-3428.2008.13.093Faced with growing of Web geography services on the network, for looking for a technology to make use of these services effectively, enabling them to work coordinately and providing better service to users, this paper makes a preliminary study on geography Web services integration principles through analysis of the portal technology that based on Web Services for Remote Portlets(WSRP) specification, and semantics service, which are popular currently, implements a prototype of integration of Web Map Services(WMS) that is based on OGC Web services common specification, and provides a unified interface for using distributed geographic Web services.
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Computer Engineering. 2008, 34(13): 262-263,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.094Rendering can convert the scenes, which are abstract descriptions with full of three-dimensional geometry models, into the actual images. Rendering is the core step in digital media making processs. This paper explores the concept of parallel rendering based on cluster system, and designs Adaptive Remote Rendering Cluster System(ARRCS) which can submit jobs to the cluster, modify the scene files, monitor the rendering process and download the final images. The correctnesss and validity of this system is proved.
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Computer Engineering. 2008, 34(13): 264-266. https://doi.org/10.3969/j.issn.1000-3428.2008.13.095A Virtual Assembly System(VAS) structure based on VRML-Java technology is presented. It makes assembly model and show model separate each other and its running is independent of computer platform. The constructing methods of VAS environment and key technique of VAS implementing are discussed. This key technique consists mostly of expression and transformation of assembly/disassembly motion, control strategies of virtual assembly process, collision detection among objects in VAS and communication between Java and VRML. The VAS simulation software is developed and validated by taking example for ball valve virtual assembly.
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Computer Engineering. 2008, 34(13): 267-269. https://doi.org/10.3969/j.issn.1000-3428.2008.13.096Coastline change has a considerable effect on sustainable development of coastal zone. Applying the ESRI’s Component Object Model(COM) object library——ArcObjects, this paper describes the method to design and implements coastline forecast system based on Microsoft C#.NET with GM(1,1). An original point and a serial of lateral lines which are superposed with the coastline vector data is set up in order to obtain forecast points. The forecast system is applied in Geographic Information System(GIS) of land resources planning in Liaoning Province.
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Computer Engineering. 2008, 34(13): 270-272. https://doi.org/10.3969/j.issn.1000-3428.2008.13.097In this paper, an algorithm is proposed to implement the large-scale 3D terrain visualization. Dynamic schedule massive data in real time is mainly based on the terrain data block partition and multithreading dynamic scheduling technique. Quad-tree data structure is used to simplify terrain meshes and cracks are eliminated by importing Y model primitive. The experimental results demonstrate that the proposed method can render large-scale terrain in real time, improve the efficiency and visual effects of terrain walkthrough.
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Computer Engineering. 2008, 34(13): 273-274,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.098This paper studies the designing and building thought of GeoFusion platform, uses other digital earth platforms for reference, analyzes different kinds of objective factors in battlefield environment, visualizes the battlefield situation information, and simulates common operation picture according to the requirement of the officer. In the demonstration process of the system, the officer may choose the observation way and object, adjust the angle of view and the viewing position. The system has strong real-time interaction.
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Computer Engineering. 2008, 34(13): 275-276,. https://doi.org/10.3969/j.issn.1000-3428.2008.13.099This paper analyzes the shortage of Microstation’s GIS framework and the structure of vector topographic map in it, and uses VBA to build a middleware which is able to distill, store, query and output the vector data. It builds the spatial property database to manage the vector data and the property data synchronously in SQL2000 Server. According to these technologies, the fundamental GIS for Daqing oilfield is built on the Microstation platform, and GIS functions is realized in CAD system.
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Computer Engineering. 2008, 34(13): 277-279. https://doi.org/10.3969/j.issn.1000-3428.2008.13.100In order to acquire ultra long period magnetotelluric signal intelligently, this paper designs data acquisition broad hardware, replants Windows CE 5.0 kernel, develops the monolithic stream drivers for data acquisition broad under Windows CE kernel, and designs the acquisition application based on the driver. The experiment on field shows that this instrument has high credibility, high precision, low power consumption, and is easy to be operated.
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Computer Engineering. 2008, 34(13): 280-282. https://doi.org/10.3969/j.issn.1000-3428.2008.13.101According to the actual demand of displaying the location of emergency calling and making fire protection plan, the auxiliary GIS system for police is developed by using MapObjects and ArcSDE. This system can display the 110 alarm point, find the shortest path between jumping-off point and end point, and choose the appropriate police to deal with the emergency. The fire protection for the important department is accomplished, and the map of campaign disposal plan can be made. The system has a tryout in Lasa city, and the effect is good.
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Computer Engineering. 2008, 34(13): 283-封三. https://doi.org/10.3969/j.issn.1000-3428.2008.13.102Vega provides the function of developing modules themselves for the users. The general dynamic extension only need set motional feature value at the beginning of rendering. The dynamic terrain need modify the bottom terrain data dynamically in the running time. This paper proposes an effective way to modify the Vega bottom data, and develops new dynamic terrain modules for Vega. Experimental results show that this method is feasible and works well.
2024
Volume 50 No 4
Volume 50 No 4
(Started in 1975, Monthly)
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428
Sponsored by：
East-China Institute of Computer Technology Shanghai Computer Society
Edited & Published by：
Editorial Board of Computer Engineering
Chief Editor：Jiang Bo
Executive Chief Editor:
Hu Bing
Tel：021-67092217
E-mail: ecice06@ecict.com.cn
CN: 31-1289/TP
ISSN: 1000-3428