05 May 2007, Volume 33 Issue 09
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Computer Engineering. 2007, 33(09): 1-3，6.Take TFT-LCD industry as an example, the multi-stage production planning in supply chain is studied in this paper. The mixed integer programming model for production planning considers the material cost in different time and the inventory cost, supposes that the market requirement and price forecast for each production are given, the maximum profit and the production plan for each factory will be obtained. Besides, a decision support system is exploited here. With the system, some what-if analysis can be done conveniently.
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Computer Engineering. 2007, 33(09): 4-6.The linear complexity of periodic sequences is one of the important security indices of stream cipher systems. Recently developments in stream ciphers point towards an interest in word-based stream ciphers, which require the study of the joint linear complexity of multi-sequences. This paper gives a new calculation method to compute the joint linear complexity of random Pn-periodic sequences over Fp. A new fast algorithm for computing the joint linear complexity of Pn-periodic sequences over Fp is proposed.
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Computer Engineering. 2007, 33(09): 7-9，21.Terrain match algorithm is one of the key technologies in seabed terrain aided navigation system (STAN). Most of terrain match algorithms are derived from aided navigation system in the airplane or the missile. When they are directly applied to STAN, the positioning precision have fallen off sharply and become unstable because of the seabed terrain particularity. Here, a new approach based on the principles of terrain contour match(TERCOM) is presented. It uses the modified Hausdorff distance as a cost function for the two strips of spatial water depth curve in the survey and the map. As the modified Hausdorff distance is quite tolerant of the small perturbations of the curves and inclusive of their direction partly, the new approach has high positioning precision and robustness. Moreover, experiments with pedestrian simulation confirm the effectiveness of the proposed approach. The system achieves higher positioning precision than that of the conventional TERCOM algorithm.
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Computer Engineering. 2007, 33(09): 10-11，5.Research on the match probability is not mature. The traditional way to calculate the probability is by means of SNR, independent pixel quantity and match times. Because of the special characteristic of radar scene, the traditional way of calculating the probability is sometimes inaccurate. The paper defines the contribution pixel quantity and provides a new method of calculating the probability. It is proved by many experiments that taking advantage of the contribution pixel quantity to calculate the probability is an effective way of counting the scene match probability.
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Computer Engineering. 2007, 33(09): 12-14，1.
The interconnection network plays an important role in performance and energy consumption of a Network-on-chip(NoC) system. PRDT(2,1) is a promising solution for the interconnection network of NoC due to its smaller diameter and average distance, constant node degree and full scalability. In this paper, a binary routing algorithm for PRDT is presented in order to improve the performance of routing for PRDT with small size. In the case that PRDT consists of no more than 16 nodes, the binary algorithm is deadlock-free without the utilization of virtual channels. Based on the binary algorithm, it proposes a fully adaptive routing algorithm which is deadlock-free by using a few virtual channels. The comparison between the deterministic, adaptive binary algorithm and the original vector algorithm is conducted in a simulation. The results show that the binary algorithm is better in performance while its hardware cost is lower. So the algorithm is readily applicable to the small PRDT-based NoC systems.
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Computer Engineering. 2007, 33(09): 15-18.This paper proposes a template match algorithm in fourier transform domain(TMFT), which is robust against geometrical change in spacial domain, and makes the template match to be a prototype match. Time-shifting of signal in time-domain is eliminated by time-shifting property of FT. Disturbance out of signal intensity is normalized by the auto-correlativity R(0). Semi-logarithm transforms the scale factor in time-domain to time-shifting. Energy distributive function is introduced to keep the correlation between template and target against the rotation relative to template signal. The experiments show that TMFT assures the constancy in template match and is available to rid the correlativity of geometrical change in time-domain.
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Computer Engineering. 2007, 33(09): 19-21.A method of supplementary variables for non-markovian stochastic Petri net is proposed, which fits for system that shares maintain resource reliability analysis. It studies analysis method of non-markovian stochastic Petri net based on supplementary variables. It takes a parallel system as an example to illustrate the new method of modeling process, solution method and gives expression of reliability indexes, and validates the feasibility of the method using exponential distribution.
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Computer Engineering. 2007, 33(09): 22-24，6.A genetic algorithm is presented for the multi-modal landscapes. It explores the searching space using orthogonal design and partitions it by the information acquired. According to the probability function based on their current optimum, it applies the standard genetic algorithm to these subspaces in order. It can recursively apply this algorithm accordings to the need. The experiments show that this algorithm, compared with other traditional genetic algorithms, converges to the global optimum more accurately within equal time. It can offer more local optimum solutions and other useful information of the searching space.
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Computer Engineering. 2007, 33(09): 25-27.The idea of interval wavelet is summarized and a general method to design interval multiwavelet is developed. The MRA of L2([0,1]) is redefined. For multiwavelet with arbitrary supports and multiplicity r, a basis of L2([0,1]) through defining scale subspace Vi([0,1]) and wavelet subspace Wi ([0,1]) is got. The double scaling equations are derived, and the filter parametric expressions of interval multiwavelet are obtained.
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Computer Engineering. 2007, 33(09): 28-30.Heterogeneous case representation in distributed environment decides whether the two features of two cases are the same and comparable in process of case retrieval. It is one of key problems of case-based reasoning (CBR) systems in distributed environment. An approach of semantic based case retrieval exploits a method to understand features of case using ontology technology. And based on the understanding of features, similarity between the two features is defined and computed. The experiment result of the prototype system verifies the efficiency of semantic based case feature mapping and case retrieval.
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Computer Engineering. 2007, 33(09): 31-33.Maximum entropy model can be used to found probability model of many natural language problem. This paper presents an approach for Chinese name recognition based on statistic model. It founds the model with maximum entropy principle, and calculates name probability by the model. It gets good recalling rates and precision by open test on actual corpus. The method is practicable.
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Computer Engineering. 2007, 33(09): 34-36.As the traditional iterate algorithm found out, the instant firing speed (IFS) of CCPN may not be used when there is actual conflict, Z.Hanzalek has proposed a method to find the IFS for maximal speed CCPN based on the resolution of actual conflicts by global priorities. Since the priority of transition is constant, it could not be variable with the dynamic parameters of CCPN. Also, the proposed method does not comply with the semantic of CCPN. This paper makes following contributions: (1)proposes a fuzzy decision model to determine the priority of a transition; (2) develops a resolution of actual conflicts according to the semantic of CCPN; (3)gives an efficient way to determine the instant firing speed of CCPN based on linear programming.
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Computer Engineering. 2007, 33(09): 37-39，4.A model of geographic mapping for Internet entities is proposed. Considering the unreliable Internet information and the expensive time using, three key techniques are discussed to achieve better result, which are mapping IP to geo-location, validating the original result, and clustering the neighbor IP. Compared with the present techniques, the model emphasizes on accurate solution and gives a concept of trust level to combine many streams of information. It does much analysis on the trust level in validating and clustering.
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Computer Engineering. 2007, 33(09): 40-42.There is a close relationship between the structures of whole genome and its functions which are expressed by its subsequences. Researching the structure of DNA sequence has a profound meaning to bioinformatics. The problem that all k-mers in whole genome are counted is researched. The internal and external algorithm which counts all k-mers occurrence in DNA sequences is designed and implemented. This algorithm translates the problem of counting all k-mers into the problem of counting integer keys with the help of a hash function which maps a k-mer to an integer, and it applies the classic B-tree algorithm to solve the problem of counting k-mers in DNA sequence. It proposes three measures to further improve the efficiency of the algorithm according to the feature of the counting problem.
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Computer Engineering. 2007, 33(09): 43-45，4.Software fault localization is always very difficult, when software fault is detected by runtime monitor. A method to fault localization with difference analysis of dual-traces is proposed. It locates software fault by analyzing the differences between successful run and faulty run. It abstracts program execution with spectrum and selects nearest neighbor successful run with distance metric. By computing longest common subsequence and maximal common adjacent subsequence set, suspicious fault location set is got finally, which is treated as fault cause. This method will reduce code scope of checking for fault localization dramatically.
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Computer Engineering. 2007, 33(09): 46-48.Fuzzy logic is applied to analyze the test characteristic of same-elements in all test cases. It is concluded that there is same effect same-elements in each test case set. Based on the result, a method which is used to generate lesser test cases (TCB) thinking about the action of combination of parameters values is given. The expression of TCB expressing all test cases is established. It is proved that TCB test can ensure that the software’s quality can satisfy user requirement and improve the ability of test cases error discover by fuzzy logic. The research is propitious to reform testing process and to reduce test cost since TCB is lesser but more efficient.
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Computer Engineering. 2007, 33(09): 49-51.Formal method B supports the whole development from abstract specifications to implementation, which is used to develop safety-critical systems in software. This paper presents the definition of refinement in B and describes the refinement process of abstract machine and its approaches. After illuminating via an example that B’s ordinary refinement rules only in terms of forward refinement are incomplete, backward refinement is introduced to endow B for the first time with two tractable and jointly complete refinement theories which together are sufficient for proving any valid refinement.
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Computer Engineering. 2007, 33(09): 52-54.Separation of duty (SoD) is a fundamental means for prevention of fraud and errors. Based on the Chinese wall security policy, a model of history-based separation of duty is implemented and it tracks the history of user’s previous permissions record, from which the current permissions assigned to can be determined. The formal description and analysis about the model has been done and the model has been proved a well in accordance with principle of SoD. The model inherits the advantage of Chinese Wall security policy and separation of duty, and provides a more perfect access control stratagem.
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Computer Engineering. 2007, 33(09): 55-57.Calculus of safe boxed ambients with password (SBAP) improves the existing calculus of the mobile ambient. It avoids the interference from open operation in the calculus of the mobile ambient, strengthens the control capability of the ambient boundary, and carries out the reclamation of the ambient. This paper gives the syntactic and semantic definition of SBAP, uses SBAP to rewrite the matching operator of Pi-calculus, and describes and emulates the E-mail system.
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Computer Engineering. 2007, 33(09): 58-59，8.Considering the key issue with respect to reducing the cost of obtaining and processing information in wireless sensor networks, this paper proposes a new research idea coupling rough set theory with the information processing. A hierarchical intelligent information processing method is presented. Meanwhile, in practice, by intelligent data analysis on three levels, i.e. local data processing, data fusion in each cluster, global attribute reduction and rule generation, a wireless sensor network paradigm for real-time forest fire detection shows that the novel approach can make it achievable for the sensor nodes to extract and transmit only the useful minimum set of high quality information automatically, leading to maximum utilization of the constrained resources on sensor nodes.
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Computer Engineering. 2007, 33(09): 60-61,9.To make easier of the verification of workflow model based on Petri nets, this paper presents a method of verification of workflow model based on reduction techniques of Petri nets. Based on a rigorous analysis of various verification techniques of workflow model, a analysis method is given aiming at non-free choice parts of Petri nets. A transformation from live and bounded non-free choice part to free choice part is given which preserves liveness and boundness. The verification of arbitrary Petri nets including non-free choice Petri nets could be transferred to the verification of free choice Petri nets. An example is introduced to illustrate how to apply the analysis method to verify a application model.
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Computer Engineering. 2007, 33(09): 62-63,1.Parallel test is a new direction for the future auto test system. At present, there are no practical architecture models for the parallel test system’s R&D both at home and abroad. This paper introduces the design and implementation process of parallel test system based on UML, which is a reference to the parallel test system’s R&D.
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Computer Engineering. 2007, 33(09): 64-65.Belief-propagation algorithm is taken in LDPC code’s decoding method, but small loops degrade the code’s performance. This paper analyzes the theory of LDPC code’s loop by tree graph and gives out the method to calculate all loops.
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Computer Engineering. 2007, 33(09): 66-68，7.
This paper presents a compiler auxiliary toolkit (COA) using analysis-specific IR. It separates the analysis implementation from development of compiler infrastructure. This paper illustrates its capability through its usage in generation of function call graph and loop invariant detection.
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Computer Engineering. 2007, 33(09): 69-71.Proper exception handling mechanism is an important means to guarantee the reliability and error-tolerance of embedded application system. In this paper, the relevant technologies of exceptions processing in embedded software design orienting communication applications are studied. Based on X86 and PowerPC hardware platforms, the running stack information is analyzed. An exception handling schema which is in common use in the communication application field is represented. And the schema’s implementation is discussed based on the commercial operating system VxWorks.
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Computer Engineering. 2007, 33(09): 72-73,1.As a technology for software reuse, component technology aims at these challenges. Component-based composition tool is used for software reuse, and makes user to develop application more easily. Composition tool is based on some kinds of component model. Now, there are two kinds of commerce component model. One is COM, which belongs to Microsoft and based on OLE. Another is Ejb/JavaBeans, which belongs to Sun. Composition tool is used for software reuse, so when designing a composition tool, the first thing which should be thought about is how to make software reuse more easily. This paper analyzes the JavaBeans, gets the features related to software reuse, extends the model, and makes it more easily for reuse. The ability of self-description is extended.
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Computer Engineering. 2007, 33(09): 74-75,7.
Under incomplete information system with default value, there are several similarity relations, such as tolerance relations, dissymmetrical similarity relation, limited tolerance relation and modified tolerance relation. But they have their own limitations. In this paper, balanced tolerance relation is presented. And it is verified that the balanced tolerance relation is more reasonable and effective.
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Computer Engineering. 2007, 33(09): 76-78.By analyzing the property and characteristics of the minimum merge dependency set of F when D has weak left side conflict or weak right side conflict, the necessary and sufficient condition under which a database schema without inside conflict can be decomposed into one meeting PS and α-acyclic is given. A decomposition algorithm is given accordingly with the proof for its termination and correction.
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Computer Engineering. 2007, 33(09): 79-81.Current works in distributed discrete event simulations depend on precise time stamps to events, but sometimes it is reasonable for modelers to use time intervals. This paper describes a time warp mechanism to exploit temporal uncertainty. The basic idea of the approach is to provide an event model in which events are assigned time intervals to exploit parallelism, a sub-mechanism to preserve causal ordering when time intervals to events overlap and a semantics sub-mechanism to prevent rollback too much. A component based on RTI is implemented, which ensures a practical time warp mechanism.
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Computer Engineering. 2007, 33(09): 82-83，8.In μC/OSII, if the point in the memory block applied by the application task is illegal and its address points the first several bytes of the head free memory block, the free memory block list is destroyed. In order to solve such problem, the control information and user space are stored separately. This paper introduces a first-level memory management algorithm which is able to distinguish 1 024 different memory blocks by extending the memory block position bytes to 16 bits.
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Computer Engineering. 2007, 33(09): 84-86.The key research work on full-text index is the search model and the efficient search algorithm upon model, with inter-relevant successive trees of excellent full-text search model, this paper presents a search algorithm based on successive parts, which accelerates the full-text search rate, and demonstrates the advantages of inter-relevant successive trees in full-text domain.
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Computer Engineering. 2007, 33(09): 87-89.By introducing ontology into the field of software-component description and retrieval, the semantic information among the components can be presented more precisely. Ontology is the representation of knowledge. It can make knowledge sharable and reusable by managing it efficiently. The utility of knowledge resource can be exploited more effectively. Ontology should be updated and maintained because intelligence is not invariable. This paper proposes a framework of ontology evolution from owl files, the research direction and key points are also discussed.
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Computer Engineering. 2007, 33(09): 90-91，1.Based on a new automatic programming method——gene expression programming(GEP), this paper presents an improved GEP mining algorithm by designing new fitness function, optimizing the processing of initialization, introducing new genetic operators and adopting(λ+μ) selection strategy which is used in evolution strategy. Experiments are done to test the new algorithm and the data sets are from UCI machine learning repository. The capability of the new algorithm to mine accurate classification rules is compared with C4.5 algorithm and traditional GEP algorithm.
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Computer Engineering. 2007, 33(09): 92-94.Reverse engineering of binary programs is a fundamental task for specialists in the fields of computer security, system verification, cryptography, and other related fields. The decompilation of C++ is a very difficult problem in reverse engineering, especially the type recovering. This paper presents a technique to recover data type based on C++ exception handling. It can find out all the local objects in a function and analyze the addresses of the object’s constructor and destructor. In specific environment, this approach is a good solution of recovering data type information in C++ decompilation.
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Computer Engineering. 2007, 33(09): 95-96.Video summarization is receiving increasing attention to mining semantic contents in huge video databases. This paper proposes a novel emantic content mining approach that mines subject keyframes by an algorithm based on vector space model. After pre-processing, video is transformed into a relational dataset of keyframe classes. Using subject keyframe detection algorithm, it keeps the pertinent keyframes that distinguish one scene from others and remove the visual-content redundancy from video content. The corresponding summary is obtained by assembling them by their original temporal order. Experiments are conducted to evaluate the effectiveness of the proposed approach with summary compression ratio and content coverage. The results demonstrate that meaningful news video summaries is generated.
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Computer Engineering. 2007, 33(09): 97-99.Some existing Web application frameworks can reduce the difficulty for business logic. It still needs a lot of programming handwork to implement, and can’t adapt to the changing system. This paper designs and implements a Web application automated construction frame, WACF. This framework can adapt to the complicated business requirement, and is able to make most of the application’s development automated by using the construction tool. The initial experiment indicates that WACF has an abroad applicability and can dramatically improve the developing efficiency.
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Computer Engineering. 2007, 33(09): 100-102.The paper proposes a method of spam filtering based on content. It adopts general suffix tree model(GSTM), takes advantage of context location, and does string match of unfixed length, then computes the similarity between test mail and the corpus to determine the sort of E-mail. The experiments and analyses prove that the method is better than other methods based on vector space model(VSM) in both accuracy and recall when tested on the same corpus. The avoidance of word segmentation shows that the categorizing process is irrelevant with the concrete language and is a language independent method.
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Computer Engineering. 2007, 33(09): 103-105.This paper combines expectation maximization(EM) algorithm and C4.5 algorithm to build a Type 2 diabetes data processing system. With the system, a series of data mining experiment is designed to seek for important Type 2 diabetes risk factors and their relationships with blood glucose. Through a large quantity of experiments, some pathological knowledge of Type 2 diabetes is obtained, which includes 2 new blood glucose threshold——5.26 and 4.28, and 8 important Type 2 diabetes risk factors. Based on these factors and the results, the relationship between the functions of those risk factors and different blood glucose thresholds is studied and illustrated. And the relationship between important risk factors and blood glucose is analyzed.
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Computer Engineering. 2007, 33(09): 106-108.Focusing on some high critical application, the conceptions of deadline, slack and critica in real-time system are introduced and improved in DSMS according to the characteristics of continuous query in DSMS. According to these new conceptions, a real-time schedule strategy based on priority is proposed. In this scheduling strategy, the earlier the deadline is or the shorter the slack is or the more critical the query is, the higher the priority is. And a structure of priority tree is proposed to realize the unique execution sequence of priority-based query. The experimental results indicate that the strategy raises the hit value ratio (HVR) and the success ratio of continuous query scheduling.
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Computer Engineering. 2007, 33(09): 109-110，.The MAC protocol of IEEE 802.16-2004 standard specifies schedule mechanisms about mesh mode, while its channel resource allocation algorithms are not specified. This paper proposes two slot allocation algorithms based on priority to achieve QoS on MAC layer. And conducts a simulation to study average delay, request reject rate, and minislot utilization based on proposed algorithm. The simulation results show that the algorithm achieves QoS of different services.
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Computer Engineering. 2007, 33(09): 111-113.IP over DVB is the key technology for IP datacasting and unidirectional lightweight encapsulation (ULE) is its latest method for encapsulating. The design and the implementation of IP-DVB gateway for satellite network are described. The gateway supports both IPv4/IPv6 protocols and MPE/ULE encapsulation methods. An application scenario in distance education is given.
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Computer Engineering. 2007, 33(09): 114-116.This paper analyzes the calculation cost and characteristics of 802.11a preamble receiving. Realization of these algorithms using SDR, which is based on an application specific DSP and S/W codesign, is introduced. An effectively DSP processor architecture is designed. The test results show this design is able to implement 11a baseband process effectively and flexibly.
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Computer Engineering. 2007, 33(09): 117-119，.The characteristic of Grid and P2P systems is analyzed, and a four-layer model called UVSP for grid and P2P resource fusion is presented that has a good character in the resource representation, discovery, access and cooperation. In UVSP model, a Bootstrap based on DHT is added into grid and a peer service is implemented in every P2P node. The resource management architecture is discussed against UVSP. A prototype experiment is realized with BT tracker functionality. The UVSP model is helpful to integrate resources in grid and P2P systems, also available to heterogeneous P2P systems as a reference for resource share and cooperation.
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Computer Engineering. 2007, 33(09): 120-122.As an important component of the network security system, the IDS didn’t work as well as expected in practice. This article analyzes the essential problem of the current NIDS, where there is too much invalid information and the NIDS almost know nothing about the network environment, which it is in. Besides, it also presents some ways to improve the NIDS. So the NIDS could discover and analyze the network environment information and work more particularly and effectively.
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Computer Engineering. 2007, 33(09): 123-125.In on-demand multicast routing protocol (ODMRP), as it updates the member and routing information by periodically broadcasting the Join-Query packets, there are many ordinary Join-Query packets in the network, causing the increase of network overhead and network jam. It uses a probabilistic routing scheme driven by energy. It sets the probability of forwarding for every node in the network according to their information of energy resource and exploits this probabilistic forwarding mechanism to reduce the number of Join-Query packets in the network. Simulation results show that the energy-driven probabilistic multicast routing protocol for MANET (p-ODMRP) reduces the overhead of network by 20% and increases the lifetime of the network when the delivering ratio meets certain constraints.
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Study on Queueing System Performance of Best Effort Service in Broad Band Integrated Service NetworkComputer Engineering. 2007, 33(09): 126-127，.Through study on using leisure channels to process best effort service in multi-service system, a new model to compute best effort service’s average delay and average processing time in the system is proposed. And the best effort service’s average delay and average processing time is simulated and the results are compared with the data computed in the new model. The differences between them are so small that the new model is feasible and reliable. A new and reliable method is provided for computing best effort service’s average delay and average processing time in the varying capacity communication system.
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Computer Engineering. 2007, 33(09): 128-130.Route flap refers to the repeated and often redundant advertisement and withdrawal of Internet routes. Route flap, always origins in one area of the network and spreads to others, thus causes instability of the network. Upgrading network nodes with new software and/or hardware will help suppress such instability. Different types of nodes are distinguished according to their abilities to deal with route flap. Simulations are performed to acquire a quantitative evaluation of the spread. Algorithms are given to acquire an efficient upgrading plan.
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Computer Engineering. 2007, 33(09): 131-133.Aiming at the security characters of large-scale network environment, a network security policy model based on domain is proposed. By applying domain and the security policy language criterion, the techniques and principles of policies’ store, finding, implementation, conflicts detection and resolution are studied. The system which applies this model is a safe one with the peculiarity of auto-managing policy.
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Computer Engineering. 2007, 33(09): 134-136.This paper introduces the general architecture of automated intrusion response systems, summarizes the possible countermeasures that make the basis of the research, and focuses on the introduction of three important techniques, including decision-making based on mobile agent, the self-adaptive technique, and cooperate technique, which are applied to a distributed intrusion detection system. By integrating the advantages of the easy extension, configuration, different environment, this system improves the ability of error tolerance and cooperation without degradation of controllability and efficiency.
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Computer Engineering. 2007, 33(09): 137-139.Efficient encryption in real-time and maintaining compliance to the syntax of video stream is the essential requirement of video security. Direct encryption of VLC codewords will usually not result in valid VLC codewords and so the encrypted video stream is not format-compliant. A scheme is proposed that DCT and MV VLC codewords are encrypted while stream format is preserved. The experimental results show that the proposed scheme combining with the encryption of FLC codewords such as INTRADC, sign bits of DCT and MV using secret key cryptography algorithm can meet the real-time constraint and provide high security level.
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Computer Engineering. 2007, 33(09): 140-141，.Most recent security-related research on Ad Hoc network focuses on malicious nodes which do the misbehavior alone. This paper details a collaborated attack method——tunnel. Through simulation based on the DSR routing protocol and NDM security method, it shows that the tunnel attack is feasible to take considerable intrusion effect even the NDM is enabled. The corresponding security advice is given in the conclusion based on the evaluation results.
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Computer Engineering. 2007, 33(09): 142-144.This paper gives an introduction to the principle of intrusion detection, explanins what is CIDF and why CIDF is needed. Based on these material, it designs a model for intrusion detection according to CIDF. To give the model high performance, it uses chains in memory to save the information of all events occurred in running time and standardlize data from the these events. In the end, it put forwards some points about expanding SID and some SIDs applied in anomaly detection.
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Computer Engineering. 2007, 33(09): 145-147，.Based on theory of weil paring and ID-based cryptography system, a new ID-based proxy blind signature is presented, which satisfies the security properties of both proxy signature scheme and blind signature scheme. The scheme which uses ID-based public key to replace the digital certification public key could effectively omit the process of getting public key from the system and reduce the interaction times and the memory space. Thus, it resolves two issues in Li’s proxy blind signature scheme, which could effectively prevent original signer from forging a valid proxy blind signature for any file and restrict the virtual proxy power of proxy signatory.
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Computer Engineering. 2007, 33(09): 148-150.How to support multi-policy in secure information systems is a research hotspot in recent years. In the paper, FMP(Framework for multi-policy) studies are divided systematically in three classes: FMP based on policy language, FMP based on security attributes and FMP based on uniformed security model. Accordingly, typical FMPs of each class are analyzed and compared, and a research direction is pointed out. A practical case of enforcing FMP in secure OS is described.
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Computer Engineering. 2007, 33(09): 151-153.Security administration is an important part of security OS and how to develop a SA for security OS accordance with common criteria is a problem worth to discuss. In the paper, a SA framework for security OS named SMFSOS, which follows EAL3 class of CC, is put forward and implemented in red-flag security OS.
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Computer Engineering. 2007, 33(09): 154-156.Based on the analysis of time-constraint role-based access control model, the problems of choosing the turn time point and security status recovery are explained, and the algorithms of choosing the turn time point which can judge the system security status in TRBAC and choosing the reasonable teminating session set which will restore the system are proposed. Therefore, the algorithm solves the conflict, to some extent, between efficiency and security caused by when the turn time point choosing is too big or too small.
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Computer Engineering. 2007, 33(09): 157-159，.Two parameters, pixel expansion and contrast, are very important in visual cryptography. It’s very difficult to optimize both of them in theory. Based on permutation, a (2,n) scheme, which existence has been proved theoretically, is proposed. The method of construction has been carried out. Simulation results demonstrate that this scheme can balance performance between pixel expansion and contrast, i.e., when the contrast is close to optimality, the pixel expansion is relatively minor.
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Computer Engineering. 2007, 33(09): 160-162.Intrusion detection technology is a very important research field on network and information security technology. In order to improve the distinguish capability of intrusion detection system, immune arithmetic and RBF network are combinated in the intrusion detection system, which is a double-layer classifiable structure. Experimental results show that the intrusion detection system based on the combination of immune arithmetic and RBF network can efficiently distinguish four attack types.
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Computer Engineering. 2007, 33(09): 163-164，.It is an important problem that providing a concurrent opening flexible and high effective security service for the cooperative e-commerce. A novel method is provided by mobile agent to resolve this problem. A history events-based security authentication method is given by the paper for resolving some security service problems in the cooperative e-commerce.
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Computer Engineering. 2007, 33(09): 165-167.In smaller granularity content protection research field, there always exist the needs of protecting part content or referred content, which might raise the conflict of multi-security rules. The conflict will make the content unavailable. This paper tries to find the source of the conflict and present algorithms of SRCDA and ICAA to solve it, and gives an example.
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Computer Engineering. 2007, 33(09): 168-170.Based on optimal normal basis in GF(2n), a high speed serial-parallel elliptic curve multiplier is proposed in the paper, through introduction of operation rules in GF(2n), elliptic curves and point operation rules, with emphasis on the discussion of the ECC chip speed and hardware resource consuming, which is induced by different field partitions. The rate of point multiply is about 981 per second after FPGA validation.
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Computer Engineering. 2007, 33(09): 171-173，.Aiming at authentication problem of VPN, this paper presents a multilevel authentication model based on LDAP authentication, application system authentication and dynamic password authentication. It describes system design process based on UML modeling. In the multisystem environment, the dynamic password authentication system realizes unified user management and remote access to the internal network safely.
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Computer Engineering. 2007, 33(09): 174-176.Public key infrastructure (PKI) is one of the most important technologies to solve cyber security. A large PKI system is usually composed by several modules. RFC2025 has already proposed a general solution for how to secure communications between those function parts. This paper introduces an implementation way and a solution according to the practical application environment. This scheme is based on RFC2025 but has a few assumption and extension: adopt object-oriented method and call back functions when implementing, cache the symmetrical keys to reduce key agreement times when using, restart key negotiation automatically under exceptional situation to ensure the availability of the symmetrical key. It’s easy to implement and use, and also can ensure security and improve efficiency.
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Computer Engineering. 2007, 33(09): 177-179.This paper puts forward a security audit system based on VPN log. It keeps watch on the running status of VPN and detects insecurity factors of system through log analysis, which improves running and defense capability of VPN.
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Computer Engineering. 2007, 33(09): 180-181.Most existing visible watermark techniques embed watermarks into the entire image or stochastic position without taking the image content into account. But for many applications, certain portions of an image are more important than the other regions, which are often called the regions of interest (ROI). This paper proposes an adaptive visible watermark technique in ROI. The watermark is embedded into the ROI. Experimental results have shown that watermarked images meet the requirements of visible watermarks quite well. ROI does receive better protection.
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Computer Engineering. 2007, 33(09): 182-183.On the conference of the international cryptology association which was convened at the United States in August 2004, professor Wang who comes from Shandong of Chinese declared that they had successfully broken the algorithms of MD5, HAVAL-128, MD4 and f RIPEMD, and used the two of the fortieth power Hash operates under any initial value to give the collision of the SHA-0. This means that the algorithms of security authentication extensively applied currently in the electronic commerce, bank system, and stock system tumblingly breaks down, which is the field of Hash function analysis. Confronting with the rigorous and ruthlessness reality, people have to try to resolve this problem in time,which is the Hash functions based data transmission problems of the stock and bank system. Therefore, this paper provides a comprehensive defense measure of data transmission in the stock and bank system.
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Computer Engineering. 2007, 33(09): 184-185，.Classical rough set theory assumed that the information systems are complete, but in real applications, many information systems are incomplete because of different reasons. This paper analyzes the rough set model in incomplete information system. A kind of generalized information table is introduced. An algorithm for calculating attribute relative reduction directly based on the generalized information table is presented in incomplete systems. Its validity is shown by examples.
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Computer Engineering. 2007, 33(09): 186-188，.Accompanied with the development of IT and market globalization, business process shows more and more dynamic, nimble and variable, that leads to more strict requirement on business process management system. Based on the relevant theory about KM and the conclusion of BPM exception, this paper analyzes the relation between process knowledge and BPM exception, and brings forth the meaning of dealing with BPM exception by making use of process knowledge, which intelligentizes the ECA rule and spreads its applying scope. Furthermore, it can improve the BPM system’s capability for exception through controlling and descending exception’s negative affection, and then make the BPM system more flexible.
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Computer Engineering. 2007, 33(09): 189-190，.An evolutionary approximation algorithm to find a minimum height for two-dimensional strip rectangular packing problem is presented. This method is mainly based on heuristic strategies and genetic algorithm. The heuristic strategies are used to calculate the height of the packing order, and then the evolutionary capability of genetic algorithm to reduce the height is used. The computational results on well-known benchmark problems show that the presented approximation algorithm can compete with other algorithms based on genetic algorithm. Especially for large test problems, it performs better.
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Computer Engineering. 2007, 33(09): 191-193.Extracting initial strongly negative data set from positive data and unlabeled data is a base for constructing a PU-oriented text classifier by two stage frame method. The limitations in the 1-DNF algorithm for getting initial strongly negative data set are described. An improved 1-DNF algorithm is proposed. The experiment result demonstrates the number of initial strongly negative examples got from positive data and unlabeled data is increased greatly, compared with original 1-DNF algorithm. The convergence speed of algorithm is accelerated, and the precision of the classifier is raised.
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Computer Engineering. 2007, 33(09): 194-195，.The biorthogonal multiwavelet filters bank with good multifilter properties is constructed by using scale biorthogonal wavelet possessing symmetry and better filtering property. Combining with Burt’s selection and averaging fusion method, this paper applies it to fusion experiment of infrared and visible image. Simulation test shows the approach can produce preferable result.
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Computer Engineering. 2007, 33(09): 196-198.According to the feature of text classification which often involves multiple, heterogeneous data sources, this paper puts forward the algorithm of multiple kernel learning. It considers that conic combinations of kernel matrices for classification leads to a convex quadratically constraint quadratic program, and it can be efficiently solved by recycling the standard SVM implementations. Experimental results show that the proposed algorithm works for hundred thousands of examples or hundreds of kernels to be combined, and it has higher recall rate and higher precision rate for classification of text email with multiple, heterogeneous data sources.
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Computer Engineering. 2007, 33(09): 199-200，.Hierarchical discriminant regression (HDR) casts classification problems (class labels as output) and regression problems (numeric values as output) into a unified regression problem. Clustering is performed in both output space and input space at each internal node, termed “doubly clustered” and discriminants in the input space are automatically derived from the clusters in the input space. A hierarchical probability distribution model is applied to the resulting discriminating subspace at each internal node. This realizes a coarse-to-fine approximation of probability distribution of the input samples. It is helpful in high-dimension data retrieval. Kernel method on clustering in input space is used, so the impact of the nonlinear border can be effectively reduced and the results of the retrieval will be more accurate.
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Computer Engineering. 2007, 33(09): 201-203，.Using heuristic algorithms to study the bandwidth, delay, delay-jitter, least-cost multicast routing problem. The paper presents a new mixed algorithm, immune-ant algorithm, by using the ability of adaption of human’s immune system for reference and using the ability of searching the global optimization of ant algorithm. Immune algorithm makes object function and subject term as antigen, and the object function corresponds to the antibody. It can control the convergence direction of the solving process. Ant algorithm generates and renews antibody. The experiment results show that the immune-ant algorithm improves the efficiency of routing greatly.
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Computer Engineering. 2007, 33(09): 204-206.An intrinsic dimensionality determination method for hyperspectral image with known class number is proposed, which is based on mixture model of probabilistic PCA. Different from common methods that determine the number of dimensionality reduction by setting the number or by eigenvalue thresholding, the algorithm simultaneously conducts dimensionality reduction and clustering under the frame of EM algorithm; and retrieves the intrinsic dimensionality according to the MMDL principle with probabilistically accurate reduced representation of the data. The method can achieve precise results applied to simulated data and real data.
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Computer Engineering. 2007, 33(09): 207-209.The problem that the boundless world knowledge formalized to indicate and to provide the computer to use is regarded as the one of the key problems which restrict natural language understanding processing to break through. This article bases on the HNC theory overall frame, carries on the world knowledge according to different domain classification, and has endue with the domain sentence category expression to each domain, loads them into computer ahead of time. The article takes the national government and the management as an example, introduces the design procedure of the domain sentence category expression, and elaborates on how to provide the computer for use.
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Computer Engineering. 2007, 33(09): 210-211，.The block match algorithm, as an important part of video compression, is the most popular for motion estimation, but its computational complexity is high. A fast algorithm for motion estimation using winner-update search strategy is presented in the paper. A simple method is proposesd to measure the complexity of the image, and the proper matching distortion set is constructed. The new algorithm reduces further the computational complexity of block matching by rearranging the searching order according to the image complexity. A corresponding data construction is designed for the new algorithm, and experimental results verify the effect of the new algorithm, it saves computations about 90%~98%.
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Computer Engineering. 2007, 33(09): 212-215.An approach based on genetic simulated annealing algorithm is proposed, which is used to solve bandwidth, delay, delay variation constraints minimum-cost multicast routing problem. In the algorithm, aiming at the limitation of genetic algorithm, integral sequence encoding method based on the preparative paths set is adopted, and the fitness function is adjusted. The cross and mutation method is improved, and simulated annealing algorithm is combined with. The simulation results show that this approach can improve the speed of convergence and avoid premature convergence. It can meet the corresponding needs of QoS in multimedia communication networks.
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Computer Engineering. 2007, 33(09): 216-218.The paper improves the traditional collaborative filtering method which needs artificial evaluation. The advanced method can gain evaluation value automatically through user transaction pattern and establish evaluation matrix. Aiming at problems of current personalized information recommendation systems, this paper applies Agent and designs collaborative filtering method to E-commerce personalized information recommendation, and designed E-commerce collaborative recommendation system based on Agent, namely, ECCRS, which is based on server. ECCRS considers time of page calling and novelty of page. It can supply recommendation service for unregister users and combined off-line processing, incremental updating and on-line recommendation. The experimental results indicate that the recommendation method of ECCRS is feasible.
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Computer Engineering. 2007, 33(09): 219-221.Although Naïve Bayesian classifier is a simple and highly efficient classification method, its attribute of independence assumption limits its real application. A new algorithm is introduced in this paper to avoid the direct influence of feature reduction on the performance of classification. This algorithm generates certain attribute subsets of the training sets through random attribute selection, constructs the corresponding Naïve Bayesian classifiers, and optimizes the Bayesian classifiers by using simulated annealing genetic algorithms. Experiment shows that this algorithm has better performance when compared with traditional Naïve Bayesian methods.
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Computer Engineering. 2007, 33(09): 222-224.Efficient processing of multimedia application is becoming one of the main bottlenecks in media application field, and many architectures have been proposed for multimedia processing. This paper classifies the contemporary processors into three groups based on programmability and evolution process: dedicated media processors, general-purpose processors with media ISA extension and multi-core media processors. An overview of media processor architectures is presented with chip examples, and the future development of media processor architectures is pointed out.
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Computer Engineering. 2007, 33(09): 225-227.This paper researches the technology and architecture of the real-time stream media transport in IP WAN, and quality control measure of media streams. A multi-layer transport architecture facing WWW is set up with agents in each transport note. Agents can be derived or canceled or changed in media streams system. In order to achieve the goal of transport stream media’s quality control, transport agents estimate the information of congestion in itself subnet, report the information to higher notes, and control the rate of media streams transport as well as accomplish media streams transport.
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Computer Engineering. 2007, 33(09): 228-230，.In order to meet the real-time video coding in embedded system and mobile device, a scalable complexity-distortion optimal motion estimation algorithm is proposed. The proposed algorithm can realize the computational complexity scalability of video encoder by adjusting complexity control parameters, and it can get the best video quality and obtain the relative optimal balance between the coding efficiency and distortion. Experimental results show that the proposed method can adjust the computational complexity of the encoder automatically according to the change of the processor’s computation ability. It can reduce the calculation expenses of motion estimation greatly, with less performance degradation and bit-rate increase.
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Computer Engineering. 2007, 33(09): 231-234.Auditory is an excellent auxiliary way of visual, the efficiency of human-computer interaction is promoted by using multi channels. Sonification is the technology to show information without any sound, and becoming a new tool to identify models and analyze data. The paper provides realizing means of sonification on CAD, concludes that CAD data type is suitable for sonification, and analyzes corresponding design of data mapping calculation. It dicusses the sonification on 2D continued data through CAD motion imitate in CAD mechanism design.
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Computer Engineering. 2007, 33(09): 235-237.A high performance DMA controller is an important component of the onchip communication architecture of SoCs such as advanced microprocessors and media processors. This paper presents a VLSI design of an AMBA-oriented 32-bit high performance DMA controller, involving dual clock domain, gated clock with synchronous reset and handshake signal routing array design. With 0.18μm library technology of SMIC, a working frequency of 180MHz is achieved. In RISC processor ALP3310, compared with transfer by software, DMA increases data transfer speed by 80.0% and 26.7% on AHB bus and APB bus respectively.
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Computer Engineering. 2007, 33(09): 238-239，.The textile information service platform system can be divided into several independent intelligent entitative Agents and the basal cell of the system is encapsulated by the frame of Agent. The Agents have the characteristics of better autonomy and active cooperation. The models of Agent information flow are constructed for some key parts of the system with the technology of MAS. Thus the main working mode of the platform is confirmed and the evaluation model of the real-time Agent state is constructed with the modeling method of fuzzy logic system. This kind of policy ensures that the Agent can adjust its working mode independently according to the status of the environment and itself, and makes full use of the limited resources reasonably.
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Computer Engineering. 2007, 33(09): 240-242.A national large-scale IPTV system needs to consider how to make its performance optimized when providing user with various multi-media services. This paper describes the architecture of IPTV system and Web cache methods. It finds the bottleneck of EPG performance after analyzing test data, and designs a cache architecture named EPG_Cache to fit IPTV system. EPG_Cache can improve EPG performance by caching part of valuable data.
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Computer Engineering. 2007, 33(09): 243-245.Viterbi algorithm is a widely used maximum likelihood estimating method. A modified algorithm is proposed to improve the decoding performance with soft-decision estimation based on IEEE 802.11a specification. The methods of re-arranging add-compare-select units, hybrid trace-back and clock gating are used to reduce operations and power. Simulation results indicate that both hardware complexity and power dissipation can be reduced but with same performance. The ASIC design is achieved under the process of SMIC 0.18μm, photo-typed in FPGA Cyclone of ALTERA.
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Computer Engineering. 2007, 33(09): 246-247，.This paper thoroughly studies the essential technology from the system integration angle which involves Web based on long-distance supervisory system design, designs a long-distance experimental system based on Web, and implements the local monitoring station design and the long-distance client side and Web server design.
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Computer Engineering. 2007, 33(09): 248-250，.While GPS is practical currently, it needs more than 4 observed GPS satellites to work. This paper presents an integrated navigation system based on the information provided by digital map, including two-satellite positioning based on the information provided by the digital map and DR system and its filtering algorithm. Experiments show that the integrated navigation system can provide precise positioning result and enhance the adaptability of vehicles in the complex environment of cities.
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Computer Engineering. 2007, 33(09): 251-254.Control scheme of drive system for paver is introduced, and hardware design of drive control system for paver is realized according to its function requirement and feature of LPC2138 CPU, such as the general architecture of drive control system, the microcontroller of LPC2138, the analog input channels, the digital input channels, the digital output channels, the output module of PWM, the communication interface. The anti-interference technique are also discussed.
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Computer Engineering. 2007, 33(09): 255-257.The paper introduces the internal logical architecture, external pins configuration and functions, the page read operations, the page program operations, the block erase operations, the write protection and command sequences and status polling of K9K8G08U0M high density NAND flash chip. It also provides the NAND flash chips to standard interface with the flash host controller.
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Computer Engineering. 2007, 33(09): 258-259，.This paper introduces a kind of audio control network based on CAN and implements the interface between the communication bus and the system’s modules. It also brings forward communication protocol for audio effect control. The audio controller takes full advantage of the characteristic of the CAN bus. So the various modules can be configured neatly and expanded easily. The technique promotes the state of the audio device’s network control performance, which is of great significance in the instrument with RS232 interface.
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Computer Engineering. 2007, 33(09): 260-262.Collaborative logistics commerce (CLC) is a new software and service strategy, which unites the market, service and customer etc. of the logistics incorporation into the global net of knowledge with the technology of Internet, and it is the conjunction of the application between the information management system of logistics enterprise and E-commerce. This article sets out from the characteristics of collaborative logistics commerce and analyzes the commercial logical model of collaborative logistics commerce, describes the systematic structure model of the system information platform of collaborative logistics commerce through the exploitation of the information platform of the traffic logistics in Hubei province, and analyzes the function of the system.
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Computer Engineering. 2007, 33(09): 263-265.In order to attain load balancing and high availability, large-scale commercial services are usually equipped with redundant resources and managed by certain management systems. However, the complex structures of services lay obstacles to the design and implementation of this kind of system. A formal model is defined, by which methods are created to describe the structures and status of the multi-tier applications and further build a platform environment. And most of complex commercial application services deployed in clusters can be governed under this kind of architecture.
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Computer Engineering. 2007, 33(09): 266-268.RPC is a common method used to inter-process communication of distributed system. RPC can provide more transparence than traditional explicit message passing. This article designs a general RPC system for embedded environment based on analysis of the RPC system architecture. This RPC system is implemented upon ARM7, μC/OS-II, Ethernet, TCP/IP. The tests of RPC and explicit message passing are performed.
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Computer Engineering. 2007, 33(09): 269-271.SQL injection has ferocious harm to E-Gov. It can break integrality of query sentence in background database by inputing some vicious sentences which contain SQL key words. Thereupon, it carries out client attack. Besides, inputing data which isn’t accordant with criterion may aggravate burden of system and reduce reliability of system at all. So the security and reliability in E-Gov system desiderates enhancing. The regular expressions have strong ability to match pattern so as to verify various data which has a varity of types. The traditional B/S frame structure can expand from three layers to four layers by adding regular expressions verifying layer. Therefore, clients are kept from being attacked by verifying input data at client. Thus security and reliability in E-Gov system is improved to a certainly level. This technology acquires good effect in the course of application in an E-Gov system.
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Computer Engineering. 2007, 33(09): 272-274.The LRU-like algorithm is proposed for the block management of augmented cache scheme. Based on the LRU-like algorithm, a kind of augmented cache named least-recently-used blocks filter cache (LBF cache) is designed. After the simulation, the performance of LBF cache shows better than some augmented caches with similar architectures (such as victim cache and assist cache), and also better than the traditional direct-mapping cache with double size.
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Computer Engineering. 2007, 33(09): 275-276，.A constructing project of the data center based on the data warehouse is introduced in the management of Dujiangyan irrigation works. This project realizes the unified management of data and the information share of every subsystem. The 2 key problems about the data warehouse――OLAP and data mining are also analyzed. The paper gives the feasibility design projects of OLAP and data mining.
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Computer Engineering. 2007, 33(09): 277-279.μC/OS-II is a stable, real-time and code-efficient operating system kernel. This paper introduces the design and implementation of an ECG monitor’s embedded software system based on μC/OS-II. The developer transplants it to the S3C2410 processor, configures it to fit this system, and creates and runs 8 tasks on this system. They communicate with each other by several message queues. It also compares and discusses the advantage and disadvantage among the systems which are without OS but with Linux and μC/OS-II. The monitor receives a high praise from cardiologists and patients. It will have a broad application anticipation.
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Computer Engineering. 2007, 33(09): 280-282.Because the heterogeneous information is relatively loose and independent, data grid is adopted to manage the distributed heterogeneous information and realize information share and integration. In this paper, information share system on data grid tool(DataGridTool)is presented as ECIShare. The information services provided realize the uniform management of different database system and file system. These services include information publishing, querying, discovering and security controlling.
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Computer Engineering. 2007, 33(09): 283-封三.Embedded system emphasizes on its cooperation and integration of software and hardware. In order to satisfy the system need, it can be cut down in function, cost, size and power. This thesis analyses the structure of the drivers of embedded device which are based on µC/OS-II operating system and the modules of MCU which connect closely with the device. It shows a technology of intermediate module to realize the cutting down of drivers by the need, which increases reuse and transplant of drivers.
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