检索结果-内蒙古大学图书馆

IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： D. Lee K.K. Ramakrishnan W.M. Moh A.U. Shankar Bell Laboratories Murray Hill NJ USA AT and T Research Laboratories Murray Hill NJ USA Department of Math. & Computer Science San Jose State University Foundation San Jose CA USA Computer Science Department University of Maryland College Park MD USA

We study both the correctness and performance of the source/destination protocol of the available bit rate (ABR) service in asynchronous transfer mode (ATM) networks. Although the basic source/destination protocol for congestion management is relatively simple, the protocol specification has to cope with several "real-world" cases such as failures and delayed/lost feedback which may introduce complexity. Rigorous proofs of the correct functioning of the protocol based on a formal specification is necessary. We use a formal extended finite state machine (EFSM) model to show that the ABR source/destination protocol is free of live-locks, so that under all conditions both resource management (RM) and data cells will be transmitted. We also show that the network options of explicit forward congestion indication (EFCI) and explicit rate (ER) interoperate correctly. We use the understanding of the informal English description of the source/destination behavior and of our EFSM model to derive conditions that ensure that the source transmission rate is stable in the presence of delayed or lost feedback RM cells, especially under the operation of a source rule that requires the reduction of the source rate under these conditions. We arrive at bounds on the number of consecutive RM cell losses tolerated while the rate remains stable. We also provide a worst-case analysis of the delay in turning around RM cells at the destination station and the worst-case inter-departure time of forward RM cells from the source.

关键词： Protocols Asynchronous transfer mode Feedback Bit rate Formal specifications Automata Resource management Erbium Delay effects Turning

来源：评论

学校读者我要写书评

暂无评论

First-order logic with two variables and unary temporal logic

First-order logic with two variables and unary temporal logi...

引用

Annual Symposium on Logic in computer science

作者： K. Etessami M.Y. Vardi T. Wilke Basic Research in Computer Science (BRICS) Centre of the Danish National Research Foundation Denmark Department of Computer Science Rice University USA Institut für Informatik und Prakt. Math. Christian-Albrechts-Universität Kiel Kiel Germany

We investigate the power of first-order logic with only two variables over /spl omega/-words and finite words, a logic denoted by FO/sup 2/. We prove that FO/sup 2/ can express precisely the same properties as linear temporal logic with only the unary temporal operators: "next", "previously", "sometime in the future", and "sometime in the past", a logic we denote by unary-TL. Moreover, our translation from FO/sup 2/ to unary-TL converts every FO/sup 2/ formula to an equivalent unary-TL formula that is at most exponentially larger, and whose operator depth is at most twice the quantifier depth of the first-order formula. We show that this translation is optimal. While satisfiability for full linear temporal logic, as well as for unary-TL, is known to be PSPACE-complete, we prove that satisfiability for FO/sup 2/ is NEXP-complete, in sharp contrast to the fact that satisfiability for FO/sup 3/ has non-elementary computational complexity. Our NEXP time upper bound for FO/sup 2/ satisfiability has the advantage of being in terms of the quantifier depth of the input formula. It is obtained using a small model property for FO/sup 2/ of independent interest, namely: a satisfiable FO/sup 2/ formula has a model whose "size" is at most exponential in the quantifier depth of the formula. Using our translation from FO/sup 2/ to unary-TL we derive this small model property from a corresponding small model property for unary-TL. Our proof of the small model property for unary-TL is based on an analysis of unary-TL types.

关键词： Logic computer science Computational complexity Polynomials

来源：评论

学校读者我要写书评

暂无评论

An improved scheme for the fuzzifier in fuzzy clustering

An improved scheme for the fuzzifier in fuzzy clustering

引用

IEEE Workshop on Neural Networks for Signal Processing

作者： L.B. Romdhane B. Ayeb S. Wang Dept. of Math. & Comput. Sci. Sherbrooke Univ. Que. Canada Mathematical and Computer Science Department Faculty of Sciences University Of Sherbrooke Sherbrooke QUE Canada

Clustering is an important research area and of practical applications in many fields. Fuzzy clustering has shown advantages over crisp and probabilistic clustering especially when there are significant overlaps between clusters. However, all of the fuzzy clustering algorithms are sensitive to an exponent parameter, namely the fuzzifier. To our knowledge, no theoretical foundations are yet available for the optimal choice of this parameter. The current work develops an improved scheme for the fuzzifier by embedding more knowledge about the data set to cluster in its computation.

关键词： Fuzzy sets Clustering algorithms Partitioning algorithms Thumb computer science Application software Embedded computing Neural networks Fuzzy neural networks Pattern recognition

来源：评论

学校读者我要写书评

暂无评论

Covering radius and discrete Chebyshev polynomials

Covering radius and discrete Chebyshev polynomials

引用

IEEE International Symposium on Information Theory

作者： I. Honkala T. Laihonen S. Litsyn Dept. of Math. Turku Univ. Finland Turku Center for Computer Science Turku Finland Department of Mathematics University of Turku Turku Finland Department of Electrical Engineering-Systems Tel-Aviv University Israel

We derive a new upper bound on the covering radius of a code as a function of its dual distance. This bound improves on the bound proved previously (Honkala et al., 1995) and in a certain interval it is also better th... 详细信息

关键词： Chebyshev approximation Polynomials Upper bound math.matics computer science Data compression Error correction codes Decoding Linear code Hydrogen

来源：评论

学校读者我要写书评

暂无评论

Learning orthographic transformations for object recognition

Learning orthographic transformations for object recognition

引用

IEEE International Conference on Systems, Man and Cybernetics

作者： G. Bebis M. Georgiopoulos S. Bhatia Dept. of Math. & Comput. Sci. Missouri Univ. St. Louis MO USA Department of Mathematics & Computer Science University of Missouri Saint Louis MO USA

Considers the problem of learning to predict the correct pose of a 3D object, assuming orthographic projection and 3D linear transformations. A neural network is trained to learn the desired mapping. First, we consider the problem of predicting all possible views that an object can produce. This is performed by representing the object with a small number of reference views and using algebraic functions of views to construct the space of all possible views that the object can produce. Fundamental to this procedure is a methodology based on singular value decomposition and interval arithmetic for estimating of the ranges of values that the parameters of algebraic functions can assume. Then, a neural network is trained using a number of views (training views) which are generated by sampling the space of views of the object. During learning, a training view is presented to the inputs of the network which is required to respond at its outputs with the parameters of the algebraic functions used to generate the view from the reference views. Compared to similar approaches in the literature, the proposed approach has the advantage that it does not require the 3D models of the objects or a large number of views, it is extendible to other types of projections, and it is more practical for object recognition.

关键词： Object recognition Neural networks math.matics computer science computer graphics Singular value decomposition Arithmetic Data preprocessing Principal component analysis

来源：评论

学校读者我要写书评

暂无评论

Utility of dynamics as indicators of stress in population models

引用

Environmental Modeling and Assessment 1997年第1-2期2卷 1-6页

作者： Hallam, Thomas G. Funasaki, Eric T. Lika, Konstadia Lee, Hooi Ling Institute for Environmental Modeling University of Tennessee Knoxville TN 37996-1300 United States Department of Mathematics University of Tennessee Knoxville TN 37996-1300 United States Dept. of Ecol. and Evol. Biology University of Tennessee Knoxville TN 37996-1300 United States Dept. of Math. and Computer Science Georgia Southern University Statesboro GA 30460 United States Dept. Ecol. Evol. and Mar. Biol. University of California Santa Barbara CA 93106 United States

The relationships between the dynamics of environmentally and chemically stressed populations and indicators of the effects of the stressor are explored in a model framework. The physiologically structured population, represented by a system of McKendrick-von Foerster hyperbolic partial differential equations, includes the dynamics of numerous individuals distinguished by ecotype. Chemical up-take of nonpolar narcotics is modeled by first order kinetics. Classical methodologies, frequency analysis and phase space reconstruction, are explored in a search for indicators of magnitude of stress. When these techniques proved generally unsuccessful for the objective of indicator selection in our model setting, summary statistics, as related to bifurcation diagrams, were constructed and appear more useful as indicators. It is concluded that physiological structures generally lead to more feasible measurable indicators of magnitude of stress than do specifics of population dynamics.

关键词： Dynamics

来源：评论

学校读者我要写书评

暂无评论

Buckets, heaps, lists, and monotone priority queues 97

Buckets, heaps, lists, and monotone priority queues

引用

Proceedings of the eighth annual ACM-SIAM symposium on Discrete algorithms

作者： Boris V. Cherkassky Andrew V. Goldberg Craig Silverstein Central Econ. and Math. Inst. Krasikova St. 32 117418 Moscow Russia NEC Research Institute 4 Independence Way Princeton NJ Computer Science Department Stanford University Stanford CA

来源：评论

学校读者我要写书评

暂无评论

Generalized output regulation for linear systems

Generalized output regulation for linear systems

引用

American Control Conference (ACC)

作者： A. Saberi A.A. Stoorvogel Zongli Lin School of Electrical Engineering and Computer Science Washington State University Pullman WA USA Department of Mathematics and Computing Science Eindhovan University of Technology Eindhoven Netherlands Department of Applied Math and Statistics State University of New York Stony Brook Stony Brook NY USA

One of the most important problems in linear multivariable control theory is that of controlling a given plant in order to have its output track (or reject) a reference (or disturbance) signal produced by some external generator, called the exosystem. The disturbance or reference contains only the frequency components of the exosystem. This is called the output regulation problem. We generalize the problem framework in several directions. One is to model disturbances and references by an exosystem that is not, unlike the traditional approach, autonomous but is driven. Another direction is to incorporate the derivative information in the problem formulation. Consequently, we formulate two classes of generalized exact and almost output regulation problems. We provide solvability conditions and the solutions to these problems. Finally, and most importantly, we show that if solvability conditions for regulation are not satisfied, one can design a regulator to achieve "best" tracking (or rejection) of reference (or disturbance) signal is any desired induced norm sense.

关键词： Linear systems Differential equations State feedback Output feedback Regulators Stability Closed loop systems math.matics computer science Statistics

来源：评论

学校读者我要写书评

暂无评论

A Robinson-Schensted Algorithm for a Class of Partial Orders

引用

Journal of Combinatorial Theory. Series A 1997年第1期79卷 36-52页

作者： Sundquist, Thomas S. Wagner, David G. West, Julian Dept. of Math. and Computer Science Dartmouth College Hanover NH 03755 United States Dept. Combinatorics and Optimization University of Waterloo Waterloo Ont. N2L 3G1 Canada Department of Mathematics Malaspina University College Nanaimo BC V9R 5S5 900 Fifth Street Canada Dept. of Mathematics and Statistics University of Victoria Victoria BC V8W 3P4 P.O. Box 3045 MS 7437 Canada

LetPbe a finite partial order which does not contain an induced subposet isomorphic with 3+1, and letGbe the incomparability graph ofP. Gasharov has shown that the chromatic symmetric functionX_Ghas nonnegative coefficients when expanded in terms of Schur functions;his proof uses the dual Jacobi-Trudi identity and a sign-reversing involution to interpret these coefficients as numbers ofP-tableau. This suggests the possibility of a direct bijective proof of this result, generalizing the Robinson-Schensted correspondence. We provide such an algorithm here under the additional hypothesis thatPdoes not contain an induced subposet isomorphic with {x>ay}. © 1997 Academic Press.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A model for simulation of nuclear physics processes

引用

International Journal of Modelling and Simulation 1997年第4期17卷 276-282页

作者： Hartati, S. Nickerson, B.G. DeMille, G.R. Department of Physics Fac. of Math. and Natural Sciences Gajah Mada University Yogyakarta Indonesia Faculty of Computer Science University of New Brunswick Fredericton NB E3B 5A3 P.O. Box 4400 Canada Department of Physics University of New Brunswick Canada Fac. of Math. and Natural Sciences Gajah Mada University Yogyakarta Indonesia University of New Brunswick Canada Rensselaer Polytechnic Institute United States

A formal knowledge representation system for nuclear physics processes, called nuclear process theory (NPT), is introduced. NPT allows modelling and simulation of nuclear physics processes. Knowledge of these processes is expressed in terms of a basic nuclear physics model and an aggregate effects model. The basic nuclear physics model is used to express knowledge of many nuclear physics processes, including fission, radioactive capture, beta positive decay, and beta negative decay. The products of these processes are expressed in either deterministic or probabilistic values. The aggregate effects model coordinates basic nuclear physics processes expressed in the basic nuclear physics model. NPT, along with the NPT simulator, can be used to reason about nuclear physics processes for approximately 3,000 different nuclides. The approach was tested using a homogeneous thermal fission reactor model. The results of modelling fission and other nuclear physics processes in a pressurized heavy water reactor fueled with a mixture of 12% U235 and 88% U236 are presented.

关键词： Knowledge representation Nondeterministic process modelling Nuclear physics reasoning Simulation and modelling

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：