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Minimal average cost of searching for a counterfeit coin: Restricted model

DISCRETE APPLIED MATHEMATICS 2006年第14期154卷 1996-2009页

作者： Liu, Wen An Ma, Hong Yong Henan Normal Univ Coll Math & Informat Sci Xinxiang 453007 Peoples R China

The following restricted model of coin-weighing problem is considered: there is a heavier coin in a set of n coins, n-1 of which are good coins having the same weight. The test device is a two-arms balance scale and each test-set is of the form A : B with vertical bar A vertical bar = vertical bar B vertical bar <= e, where e >= 1 is a given integer. We present an optimal sequential algorithm requiring the minimal average cost of weighings when the probability distribution on the coin set is uniform distribution. (c) 2006 Elsevier B.V. All rights reserved.

关键词： coin-weighing problem sequential algorithm average cost Huffman tree

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Towards structured parallel computing on architecture-independent parallel algorithm design for distributed-memory architectures

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JOURNAL OF COMPUTER AND SYSTEM SCIENCES 1996年第1期53卷 112-128页

作者： Gao, F UNIV BRITISH COLUMBIA DEPT COMP SCI VANCOUVER BC V6T 1W5 CANADA

This paper introduces an architecture-independent, hierarchical approach to algorithm design on distributed-memory architectures, in contrast to the current trend of tailoring algorithms towards specific architectures. We show that, rather surprisingly, this new approach can achieve uniformity without sacrificing efficiency. In our framework, there are three levels of algorithm design: design of a network-independent algorithm in a network-independent programming environment, design of virtual networks (virtual architectures) for the algorithm, and design of emulations of the virtual networks on physical networks. In its organizational principle, this methodology is analogous to the abstract data structure approach to sequential algorithm design. We propose the following thesis: architecture-independent optimality can lead to portable optimality. Namely, a single network-independent algorithm, when optimized network-independently, with the support of properly chosen virtual networks, can be implemented on a wide spectrum of physical networks to achieve optimality on each of them with respect to both computation and communication, We illustrate this thesis with an analysis of the example of algorithm design for ordinary matrix multiplication. In a paper by Gao, a general theory of portable optimality of parallel algorithms is presented. Besides its implications to the methodology of parallel algorithm design, our framework also suggests new questions for theoretical research in parallel computation on interconnection networks. (C) 1996 Academic Press, Inc.

关键词： Communication Complexity Computation Complexity sequential algorithm Frameworks Communication Research simulating physical network ARCHITECTURE Parallel algorithms Theses algorithms Virtual networks PARALLEL PROCESSING (COMPUTERS) algorithm design optimality Matrix multiplication

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Joint Albedo Estimation and Pose Tracking from Video

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2013年第7期35卷 1674-1689页

作者： Taheri, Sima Sankaranarayanan, Aswin C. Chellappa, Rama Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA Rice Univ Dept Elect & Comp Engn Houston TX 77251 USA Univ Maryland Dept Elect & Comp Engn Ctr Automat Res College Pk MD 20742 USA

The albedo of a Lambertian object is a surface property that contributes to an object's appearance under changing illumination. As a signature independent of illumination, the albedo is useful for object recognition. Single image-based albedo estimation algorithms suffer due to shadows and non-Lambertian effects of the image. In this paper, we propose a sequential algorithm to estimate the albedo from a sequence of images of a known 3D object in varying poses and illumination conditions. We first show that by knowing/estimating the pose of the object at each frame of a sequence, the object's albedo can be efficiently estimated using a Kalman filter. We then extend this for the case of unknown pose by simultaneously tracking the pose as well as updating the albedo through a Rao-Blackwellized particle filter (RBPF). More specifically, the albedo is marginalized from the posterior distribution and estimated analytically using the Kalman filter, while the pose parameters are estimated using importance sampling and by minimizing the projection error of the face onto its spherical harmonic subspace, which results in an illumination-insensitive pose tracking algorithm. Illustrations and experiments are provided to validate the effectiveness of the approach using various synthetic and real sequences followed by applications to unconstrained, video-based face recognition.

关键词： Albedo pose tracking spherical harmonics sequential algorithm Kalman filter Rao-Blackwellized particle filter intrinsic image statistics

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Optimally computing the shortest weakly visible subedge of a simple polygon

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JOURNAL OF algorithmS 1996年第3期20卷 459-478页

作者： Chen, DZ Department of Computer Science and Engineering University of Notre Dame Notre Dame Indiana 46556

Given an n-vertex simple polygon P, the problem of computing the shortest weakly visible subedge of P is that of finding a shortest line segment s on the boundary of P such that P is weakly visible from s (if s exists). In this paper, we present new geometric observations that are useful for solving this problem. Based on these geometric observations, we obtain optimal sequential and parallel algorithms for solving this problem. Our sequential algorithm runs in O(n) time, and our parallel algorithm runs in O(log n) time using O(n/log n) processors in the CREW PRAM computational model. Using the previously best known sequential algorithms to solve this problem would take O(n(2)) time. We also give geometric observations that lead to extremely simple and optimal algorithms for solving, both sequentially and in parallel, the case of this problem where the polygons are rectilinear. (C) 1996 Academic Press, Inc.

关键词： Optimal algorithm Parallel prefix Visibility Edge Polygon Parallel algorithms Edge of a figure or solid LITAF gene sequential algorithm Line sections visibility Optimization algorithms

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Kernel methods for clustering:: Competitive learning and c-means

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INTERNATIONAL JOURNAL OF UNCERTAINTY FUZZINESS AND KNOWLEDGE-BASED SYSTEMS 2006年第4期14卷 481-493页

作者： Inokuchi, Ryo Miyamoto, Sadaaki Univ Tsukuba Doctoral Program Risk Engn Tsukuba Ibaraki 3058573 Japan Univ Tsukuba Dept Risk Engn Tsukuba Ibaraki 3058573 Japan

Recently kernel methods in support vector machines have widely been used in machine learning algorithms to obtain nonlinear models. Clustering is an unsupervised learning method which divides whole data set into subgroups, and popular clustering algorithms such as c-means are employing kernel methods. Other kernel-based clustering algorithms have been inspired from kernel c-means. However, the formulation of kernel c-means has a high computational complexity. This paper gives an alternative formulation of kernel-based clustering algorithms derived from competitive learning clustering. This new formulation obviously uses sequential updating or on-line learning to avoid high computational complexity. We apply kernel methods to related algorithms: learning vector quantization and self-organizing map. We moreover consider kernel methods for sequential c-means and its fuzzy version by the proposed formulation.

关键词： competitive learning clustering c-means learning vector quantization self-organizing map kernel method sequential algorithm

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Estimation of time-varying heat sources through inversion of a low order model built with the Modal Identification Method from in-situ temperature measurements

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2010年第1-3期53卷 206-219页

作者： Girault, M. Videcoq, E. Petit, D. ENSMA CNRS Lab Etud Therm UMR 6608 F-86961 Futuroscope France LMEE F-91020 Evry France

An approach using an experimentally built low-order model is proposed for the estimation of time-varying heat sources. In a first step, a low order dynamical system of equations, linking up temperatures at a set of specific points to heat sources strengths, is identified from experimental data using the Modal Identification Method. In a second step, the low order model is used to efficiently solve the transient inverse problem for the estimation of heat sources intensities from temperature measurements. The proposed approach is illustrated with an experimental set-up involving thermal diffusion with convective and radiative boundary conditions. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Nonlinear heat transfer Reduced model Experimental identification Inverse problem sequential algorithm Future time steps

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Resolution of linear inverse forced convection problems using model reduction by the Modal Identification Method: application to turbulent flow in parallel-plate duct

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2004年第17-18期47卷 3909-3925页

作者： Girault, M Petit, D Univ Poitiers Lab Etud Therm CNRS UMR 6608ENSMA F-86961 Futuroscope France

Inverse Heat Convection Problems have received attention only recently. They usually involve the use of a high order model corresponding to the spatial discretization of the domain. In this numerical study, the possibility to quickly solve such a problem with a low order model is analysed. The proposed method can be applied to any forced convection problem, whatever the geometry, as far as it is linear. Starting from a Detailed Model (DM) of the system, the Modal Identification Method is applied to build a Reduced Model (RM), which can be used to solve the inverse problem. The inversion procedure is sequential and requires no iterations. The function specification method is used to stabilize the inverse problem. An illustrative application is given. Turbulent forced convection is considered, with a hydrodynamically fully developed, thermally developing, incompressible, turbulent flow of a newtonian and constant property fluid inside a parallel-plate duct. Axial conduction in the flow is neglected. Two wall heat flux densities, varying with time, are estimated from the knowledge of simulated transient temperature measurements inside the fluid. When solving the inverse problem with RM instead of DM, a drastic reduction of computing time is obtained (with a reduction factor up to 11,000 in the present study), without significant loss of accuracy. Effects of functional form of the unknowns, sensors number and position, measurement error, on the accuracy of estimates are examined. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： forced convection modal identification Reduced Model inverse method estimation of boundary conditions sequential algorithm Future Time Steps

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FINDING A CLOSEST VISIBLE VERTEX PAIR BETWEEN 2 POLYGONS

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algorithmICA 1995年第2期14卷 183-201页

作者： AMATO, NM Department of Computer Science Texas A&M University College Station USA

Given nonintersecting simple polygoris P and Q, two vertices p is an element of P and q is an element of Q are said to be visible if pq does not properly intersect P or Q. We present a parallel algorithm for finding a... 详细信息

Given nonintersecting simple polygoris P and Q, two vertices p is an element of P and q is an element of Q are said to be visible if <($$)over bar>pq does not properly intersect P or Q. We present a parallel algorithm for finding a closest pair among all visible pairs (p,q) p is an element of P and q is an element of Q. The algorithm runs in time O(log n) using O(n) processors on a CREW PRAM, where n = \P\+\Q\. This algorithm can be implemented serially in O(n) time, which gives a new optimal sequential solution for this problem.

关键词： VISIBLE VERTEX DISTANCE SIMPLE POLYGON PARALLEL algorithm PRAM sequential algorithm

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Defect chemistry modelling of oxygen-stoichiometry, vacancy concentrations, and conductivity of (La_1-xSr_x)_yMnO_3±δ

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SOLID STATE IONICS 2000年第1-4期129卷 145-162页

作者： Poulsen, FW Riso Natl Lab Dept Mat Res DK-4000 Roskilde Denmark

Two precise algorithms are devised for the calculation of defect concentrations in A-site acceptor doped ABO(3) perovskites. The two models contain nine species including cation vacancies on the A- and B-site. The small polaron model is based on three redox levels of the B-ion. A large polaron model, based on delocalised electrons, electron holes and all B-ions being trivalent is given in Appendix A. The sequential mathematical method allows us to calculate the high temperature oxygen partial pressure dependent properties of (La1-xSrx)(y)MnO3+/-delta in a unified manner irrespective of the type of defect regime, Simulations are shown for a pO(2) span from 10(-30) to 10(5) atm. The three required equilibrium constants for (La1-xSrx)(y)MnO3+/-delta had to be changed significantly from values given in literature in order to match the observed stoichiometry span. The main results shown are calculated by the small polaron model containing only ionic species - the B-ion may be Mn-B' (Mn2+), Mn-B(x) (Mn3+), and Mn-B(Mn4+). The A/B-ratio = y greatly influences the oxygen stoichiometry, oxygen ion vacancy- and cation vacancy concentrations and the total conductivity. Calculations are given for the range 0.87 less than or equal to y less than or equal to 1.13 for a Sr doping of 10% at 1000 degrees C. The defect model can simultaneously describe the observed stoichiometry and conductivity dependence on pO(2), if the electronic mobility is decreased by up to 50% at pO(2) < 10(-10) and pO(2) > 10(-2) arm. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： conductivity defect modelling LSM non stoichiometry perovskite sequential algorithm

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Direct and inverse solutions with non-Fourier effect on the irregular shape

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2010年第13-14期53卷 2685-2693页

作者： Wang, Chi-Chang Feng Chia Univ Dept Mech & Comp Aided Engn Taichung 40724 Taiwan

This study used the finite element method with linear least-squares error method to construct a simple non-iterative inverse operation procedure, for solving non-Fourier heat transfer effect in irregular geometry. Numerical validation indicated that, irregular geometry would enhance heat wave reflection and thus make temperature distribution more complex, moreover, non-Fourier heat transfer has limited heat wave propagation speed, heat information fails to be reflected in time at measure point of the other side, hence, inverse operation difficulty increases. However, sequential algorithm constructed by this study is able to estimate unknown boundary condition correctly and efficiently at every instant by only one array operation in successive time steps. In addition, by measuring a few future time temperatures, the sensitivity of estimated result to measurement error can be effectively reduced as well. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Inverse non-Fourier effect heat conduction sequential algorithm Irregular shape Linear least-squares error method Finite element method Non-iterative

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