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The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive
design environment. In this paper, a method to generate a highlight line model on an arbitrary triangular mesh is presented.
Based on the highlight line model, a technique to remove local shape irregularities of a triangular mesh is then presented.
The shape modification is done by solving a minimization problem and performing an iterative procedure. The new technique
improves not only the shape quality of the mesh surface, but also the shape of the highlight line model. It provides an intuitive
and yet suitable method for locally optimizing the shape of a triangular mesh.
Supported by National Science Foundation of China (Grant Nos. 60533070, 60625202), National Basic Research Program of China
(Grant No. 2004CB719400), National High-Tech Research & Development Program of China (Grant No. 2007AA040401), Fok Ying Tung
Education Foundation (Grant No. 111070), National Science Foundation of USA (Grant Nos. DMI-0422126, DMS-0310645), and Kentucky
Science & Technology Corporation (Grant No. COMM-Fund-712) 相似文献
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LI Jing GE JianHua WANG Yong TANG YunShuai & XIONG Xiong State Key Laboratory of Integrated Service Networks Xidian University Xi’an China State Key Laboratory of Rail Traffic Control Safety Beijing Jiaotong University Beijing 《中国科学F辑(英文版)》2009,52(6):1055-1066
A two-user cooperative diversity system based on Alamouti signaling was proposed, which utilizes the orthogonal structure
of Alamouti signaling to make cooperative users relay on the shared channel resources so that the spectral efficiency of the
traditional cooperative system can be improved. When M-ary phase shift keying (M-PSK) modulation and an improved selection decode-and-forward (SDF) relaying protocol with limited feedback are used at the
users and m(m ⩾1) receive antennas are configured at the base station, the average bit-error-rate (BER) system performance for statistically
similar uplink channels was derived and it was verified by simulations. Under various channel scenarios of interest, numerical
and simulation results show that the diversity gain achieved and the BER performance of the proposed system increase with
the interuser channel quality, and the full transmit diversity order of two can be obtained for sufficiently high interuser
signal-to-noise ratios (SNRs).
Supported by the National High-Tech Research & Development Program of China (Grant No. 2006AA01Z270), the National Natural
Science Foundation of China-Guangdong (Grant No. U0635003), the Natural Science Foundation of Shaanxi Province (Grant No.
2007F07), the “111” Project (Grant No. B08038), and the Open Research Fund of State Key Laboratory of Rail Traffic Control
and Safety, Bejing Jiaotong University (Grant No. RCS2008K003) 相似文献
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关于KDD的一类开放系统KDD的研究 总被引:5,自引:0,他引:5
On the basis of KDD(Knowledge Discovery based on Database),the paper proposes the general framework of the open KDD system-KDD*, discusses its theoretical foundation and realization of its key technology-double base cooperating mechanism. The result of initial illustration shows that the structure of KDD' is effective and available. 相似文献
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文章在KDD(基于数据库的知识发现)的基础上,提出了KDD的开放系统-KDD的总体框架;探讨了其关键技术-双库协同机制的理论基础与实现技术。该系统提供了广泛应用于多个领域的知识发现结构与进程,具体的实例演示表明KDD这类新型构造是有效与可行的。 相似文献
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William K. Michener James H. Beach Matthew B. Jones Bertram Ludäscher Deana D. Pennington Ricardo S. Pereira Arcot Rajasekar Mark Schildhauer 《Journal of Intelligent Information Systems》2007,29(1):111-126
The Science Environment for Ecological Knowledge (SEEK) is a knowledge environment that is being developed to address many
of the current challenges associated with data accessibility and integration in the biodiversity and ecological sciences.
The SEEK information technology infrastructure encompasses three integrated systems: (1) EcoGrid—an open architecture for
data access; (2) a Semantic Mediation System based on domain-specific ontologies; and (3) an Analysis and Modeling System
that supports semantically integrated analytical workflows. Multidisciplinary scientists and programmers from multiple institutions
comprise the core development team. SEEK design and development are informed by three multidisciplinary teams of scientists
organized in Working Groups. The Biodiversity and Ecological Analysis and Modeling Working Group informs development through
evaluation of SEEK efficacy in addressing biodiversity and ecological questions. The Knowledge Representation Working Group
provides knowledge representation requirements from the domain sciences and develops the corresponding knowledge representations
(ontologies) to support the assembly of analytical workflows in the Analysis and Modeling System, and the intelligent data
and service discovery in the EcoGrid. A Biological Classification and Nomenclature Working Group investigates solutions to
mediating among multiple taxonomies for naming organisms. A multifaceted education, outreach and training program ensures
that the SEEK research products, software, and information technology infrastructure optimally benefit the target communities.
This work is based upon work supported by the National Science Foundation under Grant Nos. ITR 0225676, 0225674 and DBI-0129792,
as well as DARPA (N00014-03-1-0900). Any opinions, findings and conclusions or recommendations expressed in this material
are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF) or DARPA. 相似文献
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A min-max model predictive control strategy is proposed for a class of constrained nonlinear system whose trajectories can
be embedded within those of a bank of linear parameter varying (LPV) models. The embedding LPV models can yield much better
approximation of the nonlinear system dynamics than a single LTV model. For each LPV model, a parameter-dependent Lyapunov
function is introduced to obtain poly-quadratically stable control law and to guarantee the feasibility and stability of the
original nonlinear system. This approach can greatly reduce computational burden in traditional nonlinear predictive control
strategy. Finally a simulation example illustrating the strategy is presented.
Supported by the National Natural Science Foundation of China (Grant Nos. 60774015, 60825302, 60674018), the National High-Tech
Research & Development Program of China (Grant No. 2007AA041403), the Specialized Research Fund for the Doctoral Program of
Higher Education of China (Grant No. 20060248001), and partly by Shanghai Natural Science Foundation (Grant No. 07JC14016) 相似文献
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A digital authentication watermarking scheme for JPEG images with superior localization and security 总被引:1,自引:0,他引:1
The drawbacks of the current authentication watermarking schemes for JPEG images, which are inferior localization and the
security flaws, are firstly analyzed in this paper. Then, two counterferiting attacks are conducted on them. To overcome these
drawbacks, a new digital authentication watermarking scheme for JPEG images with superior localization and security is proposed.
Moreover, the probabilities of tamper detection and false detection are deduced under region tampering and collage attack
separately. For each image block, the proposed scheme keeps four middle frequency points fixed to embed the watermark, and
utilizes the rest of the DCT coefficients to generate 4 bits of watermark information. During the embedding process, each
watermark bit is embedded in another image block that is selected by its corresponding secret key. Since four blocks are randomly
selected for the watermark embedding of each block, the non-deterministic dependence among the image blocks is established
so as to resist collage attack completely. At the receiver, according to judging of the extracted 4 bits of watermark information
and the corresponding 9-neighbourhood system, the proposed scheme could discriminate whether the image block is tampered or
not. Owing to the diminishing of false detection and the holding of tamper detection, we improve the accuracy of localization
in the authentication process. Theoretic analysis and simulation results have proved that the proposed algorithm not only
has superior localization, but also enhances the systematic security obviously.
Supported by the National Natural Science Foundation of China (Grant No. 60572027), the Program for New Century Excellent
Talents in University of China (Grant No. NCET-05-0794), the Sichuan Youth Science & Technology Foundation (Grant No. 03ZQ026-033),
the National Defense Pre-research Foundation of China (Grant No. 51430804QT2201) and the Application Basic Foundation of Sichuan
Province, China (Grant No. 2006 J13-10) 相似文献
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As the hot line in NP-hard problems research in recent years, backbone analysis is crucial for phase transition, hardness, and algorithm design. Whereas theoretical analysis of backbone and its applications in algorithm design are still at a begin- ning state yet, this paper took the quadratic assignment problem (QAP) as a case study and proved by theoretical analysis that it is NP-hard to find the backbone, i.e., no algorithm exists to obtain the backbone of a QAP in polynomial time. Results of this paper showed that it is reasonable to acquire approximate backbone by inter- section of local optimal solutions. Furthermore, with the method of constructing biased instances, this paper proposed a new meta-heuristic -- biased instance based approximate backbone (BI-AB), whose basic idea is as follows: firstly, construct a new biased instance for every QAP instance (the optimal solution of the new instance is also optimal for the original one); secondly, the approximate backbone is obtained by intersection of multiple local optimal solutions computed by some existing algorithm; finally, search for the optimal solutions in the reduced space by fixing the approximate backbone. Work of the paper enhanced the research area of theoretical analysis of backbone. The meta-heuristic proposed in this paper provided a new way for general algorithm design of NP-hard problems as well. 相似文献
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New delay-dependent criterion for the stability of recurrent neural networks with time-varying delay
This paper is concerned with the global asymptotic stability of a class of recurrent neural networks with interval time-varying
delay. By constructing a suitable Lyapunov functional, a new criterion is established to ensure the global asymptotic stability
of the concerned neural networks, which can be expressed in the form of linear matrix inequality and independent of the size
of derivative of time varying delay. Two numerical examples show the effectiveness of the obtained results.
Supported by the National Natural Science Foundation of China (Grant Nos. 60534010, 60728307, 60774048, 60774093), the Program
for Cheung Kong Scholars and Innovative Research Groups of China (Grant No. 60521003) and the National High-Tech Research
& Development Program of China (Grant No. 2006AA04Z183), China Postdoctoral Sciencer Foundation (Grant No. 20080431150), and
the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200801451096) 相似文献
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Domain analysis is the activity of identifying and representing the relevant information in a domain,so that the information can be shared and reused in similar systems.But until now,no efficient approaches are available for capturing and representing the results of domain analysis and then for sharing and reusing the domain knowledge.This paper proposes an ontology-oriented approach for formalizing the domain models.The architecture for the multiple-layer structure of the domain knowledge base is also discussed.And finally,some genetic algorithm-based methods have been given for supporting the knowledge sharing and reusing. 相似文献
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In this paper, the concept of globally exponentially attractive set is proposed and used to consider the ultimate bounds of the family of Lorenz systems with varying parameters. Explicit estimations of the ultimate bounds are derived. The results presented in this paper contain all the existing results as special cases. In particular, the critical cases, b→ 1^+ and a→0^+, for which the previous methods failed, have been solved using a unified formula. 相似文献
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Branch query processing is a core operation of XML query processing. In recent years, a number of stack based twig join algorithms
have been proposed to process twig queries based on tag stream index. However, in tag stream index, each element is labeled
separately without considering the similarity among elements. Besides, algorithms based on tag stream index perform inefficiently
on large document. This paper proposes a novel index, named Clustered Chain Path Index, based on a novel labeling scheme.
This index provides efficient support for processing branch queries. It also has the same cardinality as 1-index against tree
structured XML document. Based on CCPI, efficient algorithms, KMP-Match-Path and Related-Path-Segment-Join, are proposed to
process queries efficiently. Analysis and experimental results show that proposed query processing algorithms based on CCPI
outperform other algorithms and have good scalability.
This paper is partially supported by Natural Science Foundation of Heilongjiang Province, Grant No. zjg03-05 and National
Natural Science Foundation of China, Grant No. 60473075 and Key Program of the National Natural Science Foundation of China,
Grant No. 60533110. 相似文献
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This paper presents the definition of multi-dimensional scalability of the Internet architecture, and puts forward a mathematical method to evaluate Internet scalability based on a variety of constraints. Then, the method is employed to study the Internet scalability problem in performance, scale and service scalability. Based on the examples, theoretical analysis and experimental simulation are conducted to address the scalability issue. The results show that the proposed definition and evaluation method of multi-dimensional Internet scalability can effectively evaluate the scalability of the Internet in every aspect, thus providing rational suggestions and methods for evaluation of the next generation Internet architecture. 相似文献
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Marianne LaFrance 《AI & Society》1991,5(2):161-171
Knowledge engineering is the term given to the process of developing expert systems and knowledge engineers are the people who acquire the requisite knowledge from experts and structure that knowledge into a useable computer program. As knowledge engineering becomes a more accepted technology, there is increasing concern about attendant social costs, such as job displacement or possible exploitation of experts. This paper reports on our efforts to explore this latter issue by scrutinizing how knowledge engineers think about the domain expert and the role that person plays in system development. To accomplish this aim, we asked several samples of novice engineers to write story completions to a preamble that describes a knowledge engineer encountering a reluctant expert who may be fearing job loss if the system is implemented. The resulting accounts were content-analysed for insights as to how novice system builders think about experts. The results indicate that experts are conceived more as a tool to be used rather than a person to be respected.Preparation of this chapter was supported by National Science Foundation Grant BNS 87-21882 to Marianne LaFrance. 相似文献
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Perfect forward secure identity-based authenticated key agreement protocol in the escrow mode 总被引:1,自引:0,他引:1
CHOO Kim-Kwang Raymond 《中国科学F辑(英文版)》2009,52(8):1358-1370
The majority of existing escrowable identity-based key agreement protocols only provide partial forward secrecy. Such protocols are, arguably, not suitable for many real-word applications, as the latter tends to require a stronger sense of forward secrecy—perfect forward secrecy. In this paper, we propose an efficient perfect forward-secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Biline... 相似文献
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This brief paper reports a hybrid algorithm we developed recently to solve the global optimization problems of multimodal
functions, by combining the advantages of two powerful population-based metaheuristics—differential evolution (DE) and particle
swarm optimization (PSO). In the hybrid denoted by DEPSO, each individual in one generation chooses its evolution method,
DE or PSO, in a statistical learning way. The choice depends on the relative success ratio of the two methods in a previous
learning period. The proposed DEPSO is compared with its PSO and DE parents, two advanced DE variants one of which is suggested
by the originators of DE, two advanced PSO variants one of which is acknowledged as a recent standard by PSO community, and
also a previous DEPSO. Benchmark tests demonstrate that the DEPSO is more competent for the global optimization of multimodal
functions due to its high optimization quality.
Supported by the National Natural Science Foundation of China (Grant No. 60374069), and the Foundation of the Key Laboratory
of Complex Systems and Intelligent Science, Institute of Automation, Chinese Academy of Sciences (Grant No. 20060104) 相似文献
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A new proof of a theorem of Hopcroft, Paul, and Valiant is presented: Every deterministic multitape Turing machine of time complexityT(n) can be simulated by a deterministic Turing machine of space complexityT(n)/logT(n). The proof includes an overlap argument.Supported by National Science Foundation Grant No. MCS-78-04343.Supported by National Science Foundation Grant No. MCS-77-19754 and the Fannie and John Hertz Foundation. 相似文献