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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Dynamic complexity investigates the required effort to maintain knowledge about a property of a structure under changing operations.
This article introduces a refined notion of dynamic problems which takes the initial structure into account. It develops the
basic structural complexity notions accordingly. It also shows that the dynamic version of the LOGCFL-complete problem D2LREACH(acyclic) can be maintained with first-order updates. 相似文献
992.
We consider the problem of scheduling jobs on related machines owned by selfish agents. We provide a 5-approximation deterministic
truthful mechanism, the first deterministic truthful result for the problem. Previously, Archer and Tardos showed a 2-approximation
randomized mechanism which is truthful in expectation only (a weaker notion of truthfulness). In case the number of machines
is constant, we provide a deterministic Fully Polynomial-Time Approximation Scheme (FPTAS) and a suitable payment scheme that
yields a truthful mechanism for the problem. This result, which is based on converting FPTAS to monotone FPTAS, improves a
previous result of Auletta et al., who showed a (4 + ε)-approximation truthful mechanism. 相似文献
993.
Dragan Simić Svetlana Simić 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2007,11(12):1185-1192
A concept of business intelligent system for financial prediction is considered in this paper. It provides data needed for
fast, precise and good business decision support to all levels of management. The aim of the project is the development of
a new online analytical processing oriented on case-based reasoning (CBR) where a previous experience for every new problem
is taken into account. Methodological aspects have been tested in practice as a part of the management information system
development project of “Novi Sad Fair”. A case study of an improved application of CBR in prediction of future payments is
discussed in the paper.
This paper is originally presented at The International Conference on Hybrid Information Technology 2006, at the special session
on “Intelligent Information Systems for Financial Engineering”, November 2006 in Cheju Island, Korea. 相似文献
994.
In this article, we describe a knowledge-based controlled platform using program supervision techniques. This platform eases
the creation and the configuration of video surveillance systems. Several issues need to be addressed to provide a correct
system configuration: (1) to choose, among a library of programs, those which are best satisfying a given user request, (2)
to assign a correct value for each program parameter, (3) to evaluate performances and to guarantee a performance rate which
is satisfactory regarding end-user requirements. This platform is composed of three main components: the library of programs,
the knowledge base and the control component. The knowledge is either given by experts or learnt by the system. The control
is generic in the sense that it is independent of any application. To validate this platform, we have built and evaluated
six video surveillance systems which are featured with three properties: adaptability, reliability and real-time processing. 相似文献
995.
The multi-homogeneous Bezout number is a bound for the number of solutions of a system of multi-homogeneous polynomial equations,
in a suitable product of projective spaces. Given an arbitrary, not necessarily multi-homogeneous, system, one can ask for
the optimal multi-homogenization that would minimize the Bezout number. In this paper it is proved that the problem of computing,
or even estimating, the optimal multi-homogeneous Bezout number is actually NP-hard. In terms of approximation theory for
combinatorial optimization, the problem of computing the best multi-homogeneous structure does not belong to APX, unless P
= NP. Moreover, polynomial-time algorithms for estimating the minimal multi-homogeneous Bezout number up to a fixed factor
cannot exist even in a randomized setting, unless BPP ⫆ NP. 相似文献
996.
Georgios D. Styliaras Georgios K. Tsolis Chris M. Papaterpos 《International Journal on Digital Libraries》2007,8(1):61-78
In this paper, AssetCollector is presented, which is a system for managing collections of cultural assets. AssetCollector
covers the needs of collection curators towards defining, populating and searching a collection in a flexible way, while supporting
them in generating reports based on the collection’s assets and reusing them in order to build web sites and CD-ROMs. In order
to support the above functionality, the system provides the content structuring subsystem, the content input subsystem, the
search subsystem and the report subsystem. The use of the subsystems is straightforward and requires no technical skills from
the curators. AssetCollector has been successfully applied for organizing various collections of cultural assets in Greece,
such as archaeological sites, museums and published books. In the future, an evaluation procedure is planned in order to further
refine the use of the system according to the targeted users’ needs. Furthermore, more import and export facilities will be
provided, which will make the system compliant with widely accepted standards. 相似文献
997.
998.
999.
Jules Sadefo Kamdem 《Computing and Visualization in Science》2007,10(4):197-210
In this paper, we generalize the Linear VaR method from portfolios with normally distributed risk factors to portfolios with
mixture of elliptically distributed ones. We treat both the Expected Shortfall and the Value-at-Risk of such portfolios. Special
attention is given to the particular case of a mixture of multivariate t-distributions.
This is a part of J. SADEFO-KAMDEM PhD Thesis[12] of the Université de Reims, France . It has been presented at the workshop
on modelling and computation in Financial Engineering at Bad Herrenalb, Germany May 6-8, 2003. The author is an associate
professor at the Department of mathematics, université d’Evry Val d’Essonne. 相似文献
1000.
C. Janke R. Jones S. Öberg P. R. Briddon 《Journal of Materials Science: Materials in Electronics》2007,18(7):775-780
Boron is observed to diffuse very slowly in germanium, as opposed to its behaviour in silicon where it exhibits Transient
Enhanced Diffusion effects in implanted samples. As a result of this slow diffusion, boron is a very stable dopant, allowing
devices to be created with very well-defined doping regions. To understand this superior performance, calculations were performed
on a variety of boron diffusion paths, within vacancy and interstitial mediated methods. It was found that the vacancy mediated
diffusion which is associated with the fast diffusion of many other species in germanium exhibits a total barrier of 5.8 eV.
Interstitial-mediated diffusion had a total barrier for migration of 3.4 eV in the neutral and singly negative charge states,
3.2 eV for the positive charge state, but a formation barrier of 4.1 eV. Thus the barrier for interstitial-mediated diffusion
is dominated by the formation energy of the self-interstitial. 相似文献