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1.
The procedure of hypertext induced topic search based on a semantic relation model is analyzed, and the reason for the topic drift of HITS algorithm was found to prove that Web pages are projected to a wrong latent semantic basis. A new concept-generalized similarity is introduced and, based on this, a new topic distillation algorithm GSTDA(generalized similarity based topic distillation algorithm) was presented to improve the quality of topic distillation. GSTDA was applied not only to avoid the topic drift, but also to explore relative topics to user query. The experimental results on 10 queries show that GSTDA reduces topic drift rate by 10% to 58% compared to that of HITS(hypertext induced topic search) algorithm, and discovers several relative topics to queries that have multiple meanings.  相似文献   

2.
郑武  Song  Wentao  Zhang  Haibin  Xu  Youyun 《高技术通讯(英文版)》2007,13(2):184-188
A reduced-complexity detection algorithm is proposed, which is applied to iterative receivers for multiple-input multiple-output (MIMO) systems. Unlike the exhaustive search over all the possible trans-mitted symbol vectors of the optimum maximum a posteriori probability (MAP) detector, the new algo-rithm evaluates only the symbol vectors that contribute significantly to the soft output of the detector. The algorithm is facilitated by carrying out the breadth-first search on a reconfigurable tree, constructed by computing the symbol reliability of each layer based on zero-forcing criterion and reordering the symbols according to the symbol reliabilities. Simulations are presented and the good performance of the new algo-rithm over a quasi-static Rayleigh channel even for relatively small list sizes are proved.  相似文献   

3.
A view of manufacturing processes is presented in which five distinct categories are defined as casting, deformation, machining, joining, and solid freeforming. Solid freeforming is essentially biomimetic and shares problems of morphogenesis with natural processes. Our team in University of London has been exploring three mechanisms of solid freeforming. In dry powder deposition and direct ink-jet printing, the emphasis has turned to the problem of delivering a complex shape in which the three dimensional spatial arrangement of composition is delivered from the design file. In extrusion freeforming, the aim is to control microstructure at hierarchical levels also from the design file. The quest for 3-D functional gradients is satisfied by acoustic and ultrasonic dispensing and mixing of powders so that each layer can be patterned. These methods could be extended to deliver the complex patterns demanded by left-handed microwave metamaterials. Dry powder deposition and direct ink-jet printing are turning towards combinatorial methods in which multiple sample libraries are used to accelerate discovery. In turn, this paves the way for ’autonomous research machines’ which steer their own search refinements in response to our requests for new materials. In this way, solid freeforming used for sample preparation can give an ’arm’ to an intelligent machine so that it can conduct its own experimentation and learning; an idea that originated with Alan Turing in the late 1940s.  相似文献   

4.
A method of combining SE-tree to compute all minimal hitting sets   总被引:3,自引:0,他引:3  
In model-based diagnosis, the candidate diagnostic results are generally characterized by all minimal hitting sets for the collection of all conflict sets. In this paper, a new method is proposed to judge a hitting set by the number of conflict sets corresponding to components, and the computing procedure is formalized by combining revised SE-tree (set enumeration tree) with closed nodes to generate all minimal hitting sets. Results show that because closed nodes are added into SE-tree, the search efficiency is highly improved. Furthermore, the proposed method is easy to be understood and implemented. Compared with other effective algorithms with completeness in some experimental tests, the diagnosis efficiency of our proposed method is higher, particularly for single- and double-fault diagnosis.  相似文献   

5.
Preface     
In the twenty-first century, network and information secu- rity is becoming the critical foundation of cyberspace for a new way of life and a new approach to fighting wars. From the perspective of a national strategy, the scandal about Snowden and the National Security Agency's PRISM has shown that all network information, communication information, and individuals' Internet behavior are under surveillance in the global world by those countries domi- nant in information technology (IT). In 2011, the USA released the "International Strategy for Cyberspace" [1], which embodies a new trend in global cyber security, with the US cyber security strategy changing from defense to offense. Corresponding to this trend, in recent years the army network warfare battalion of the USA has launched massive hacking attacks and exploitations against our national network infrastructure.  相似文献   

6.
7.
The degree-constrained minimum spanning tree (DCMST) is an NP-hard problem in graph theory. It consists of finding a spanning tree whose vertices should not exceed some given maximum degrees and whose total edge length is minimal. In this paper, novel mathematical properties for DCMST are indicated which lead to a new reduction algorithm that can significantly reduce the size of the problem. Also an algorithm for DCMST to solve the smaller problem is presented which has been preprocessed by reduction algorithm.  相似文献   

8.
A neural network model with a special structure, which is divided into linear and nonlinear parts, was proposed for identification of a nonlinear system. In this model, the nonlinear part of the object is treated as a measured disturbance, and is compensated by a feed forward method; an adaptive pole placement algorithm is used to control the linear part of the object. The simulation results show that the identification efficiency and accuracy are improved when the new controller is applied to sintering finish point control.  相似文献   

9.
A new algorithm is presented for computing the volume of revolution, moment of area and centroid etc. , which are related to the integration of rational curves. In this algorithm rational curve with high degree is firstly approximated by those with lower degree through endpoint interpolation. And finally the closed form integration solution is derived for quadratic rational curve. The diminishing rate of the minimum norm of the perturbation vector needed by degree reduction is 0(2" ") when the interval is subdivided at the midpoint. Combining the subdivision with the degree reduction, we can obtain a faster convergence of integration approximation. A series of integral error bound functions which are fairly simple to compute are derived. The examples given in this paper show that this algorithm is a simple and time-saving method in computing with small tolerance.  相似文献   

10.
A new method which is a combination of sensitivity analysis and modal synthesis technique was applied to the simple calculation of design sensitivities of the dynamic characteristics of substructurally combined rotating systems. In this paper the free interface mode method was introduced as a basic tool for the modal synthesis technique. As an example, the sensitivities of the critical speeds of a high-specd winding mechanism on textile machine with respect to design modifications were obtained by the new method introduced in this paper and compared with the values obtained by using another method.  相似文献   

11.
A vision based query interface annotation meth od is used to relate attributes and form elements in form based web query interfaces, this method can reach accuracy of 82%. And a user participation method is used to tune the result; user can answer "yes" or "no" for existing annotations, or manually annotate form elements. Mass feedback is added to the annotation algorithm to produce more accurate result. By this approach, query interface annotation can reach a perfect accuracy.  相似文献   

12.
This paper presents the logic relationship between rural settlement reconstruction and soil conservation in the Upper Yangtze River. Firstly, by introducing the concepts of "flow" and "intercepted flow", we probe into the dynamic mechanism on interaction between ecological and environmental system, and then point out that the "intercepting sites" are physical conditions for establishment of human settlements in mountains. Secondly, by using ecological theories, "flow", "source", and "sink", material cycle and energy flow in mountains have been discussed. Thirdly, according to dissipative structure theory and thermodynamic laws, a hypothesis has been proposed that "entropy flow" is a dynamic force for settlement evolution. Finally, it is argued that a project for soil conservation is set to control and utilize flows so rural settlements can be supported and farmers' life improved.  相似文献   

13.
One-dimensional carbon nano-materials (ODCNMs) synthesized from ethanol flames exhibit various agglomerated morphologies, such as "chrysanthemum-like", "hairball-like" or "orange-peel-like", "vertically aligned" and "wrinkling-pileup". The present work studied the agglomerating process and the growth mechanism by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is thought that the size and distribution of the catalyst particles produced from pretreatment of the substrates play a key role during the formation of agglomerations. It is expected that the steady growth of ODCNMs in flames will be improved through the preparation of the catalysts.  相似文献   

14.
Building Intrusion Tolerant Software System   总被引:1,自引:0,他引:1  
In this paper, we describe and analyze the hypothesis about intrusion tolerance software system, so that it can provide an intended server capability and deal with the impacts caused by the intruder exploiting the inherent security vulnerabilities. We present some intrusion tolerance technology by exploiting N-version module threshold method in con-structing multilevel secure software architecture, by detecting with hash value, by placing an ““““““““antigen““““““““ word next to the return address on the stack that is similar to human immune system, and by adding ““““““““Honey code““““““““ nonfunctional code to disturb intruder, so that the security and the availability of the software system are ensured.  相似文献   

15.
A novel personalized Web search model is proposed. The new system, as a middleware between a user and a Web search engine, is set up on the client machine. It can learn a user's preference implicitly and then generate the user profile automatically. When the user inputs query keywords, the system can automatically generate a few personalized expansion words by computing the term-term associations according to the current user profile, and then these words together with the query keywords are submitted to a popular search engine such as Yahoo or Google. These expansion words help to express accurately the user's search intention. The new Web search model can make a common search engine personalized, that is, the search engine can return different search results to different users who input the same keywords. The experimental results show the feasibility and applicability of the presented work.  相似文献   

16.
We consider a distribution system with one supplier and two retailers. For the two retailers, they face different demand and are both risk averse. We study a single period model which the supplier has ample goods and the retailers order goods separately. Market search is measured as the fraction of customers who unsatisfied with their "local" retailer due to stock-out, and search for the goods at the other retailer before leaving the system. We investigate how the retailers game for order quantity in a Conditional Value-at-Risk framework and study how risk averse degree, market search level, holding cost and backorder cost influence the optimal order strategies. Furthermore, we use uniform distribution to illustrate these results and obtain Nash equilibrium of order strategies.  相似文献   

17.
Association rule mining is an important issue in data mining. The paper proposed an binary system based method to generate candidate frequent itemsets and corresponding supporting counts efficiently, which needs only some operations such as "and", "or" and "xor". Applying this idea in the existed distributed association rule mining al gorithm FDM, the improved algorithm BFDM is proposed. The theoretical analysis and experiment testify that BFDM is effective and efficient.  相似文献   

18.
Considering the special requirements of group enterprise information management software, a new method of massive software development was put forward basing on the component technology and facing the "assemblage". It generalizes five key parts of the method system including the overall strategy, the application project method basing on the operation "assemblage", the field project method basing on component, the development method facing the component on the basis of the visible component platform, and the software development process model basing on the component "assemblage". Besides, this paper describes the process and principle of this method application with an example of the construction of a Communications Investment Group enterprise's management information system. The method provides a new idea for breaking away from the predicament appeared in the construction of present enterprise informatization and exploring the way of software industrialization.  相似文献   

19.
To alleviate the scalability problem caused by the increasing Web using and changing users' interests, this paper presents a novel Web Usage Mining algorithm-Incremental Web Usage Mining algorithm based on Active Ant Colony Clustering. Firstly, an active movement strategy about direction selection and speed, different with the positive strategy employed by other Ant Colony Clustering algorithms, is proposed to construct an Active Ant Colony Clustering algorithm, which avoid the idle and "flying over the plane" moving phenomenon, effectively improve the quality and speed of clustering on large dataset. Then a mechanism of decomposing clusters based on above methods is introduced to form new clusters when users' interests change. Empirical studies on a real Web dataset show the active ant colony clustering algorithm has better performance than the previous algorithms, and the incremental approach based on the proposed mechanism can efficiently implement incremental Web usage mining.  相似文献   

20.
Current peer-to-peer (P2P) applications suffer performance degradation from the problems such as load imbalance, topology mismatch between overlay and underlay, and instability caused by node joining and leaving. In this paper, we propose the idea of implementing 2 functions of routing message and maintaining service index on different layers of overlay to deal with the aforementioned problems. Taking Chord as example, we design algorithms for building cluster and overlay and implement function-separated (FUSE) overlay with 2-dimensional address ID space. We further propose an analytic model for describing node’s load for evaluation. Simulation results indicate that, compared with 2-layer Chord-centered overlay in previous researches, this overlay excels in the metrics such as query path length, load, and query delivery ratio. Biography: LI Wenxiang(1979–), male, Lecturer, research direction: P2P computing, mobile computing.  相似文献   

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