Results 1  10
of
806
Iterative point matching for registration of freeform curves and surfaces
, 1994
"... A heuristic method has been developed for registering two sets of 3D curves obtained by using an edgebased stereo system, or two dense 3D maps obtained by using a correlationbased stereo system. Geometric matching in general is a difficult unsolved problem in computer vision. Fortunately, in ma ..."
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Cited by 659 (7 self)
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A heuristic method has been developed for registering two sets of 3D curves obtained by using an edgebased stereo system, or two dense 3D maps obtained by using a correlationbased stereo system. Geometric matching in general is a difficult unsolved problem in computer vision. Fortunately, in many practical applications, some a priori knowledge exists which considerably simplifies the problem. In visual navigation, for example, the motion between successive positions is usually approximately known. From this initial estimate, our algorithm computes observer motion with very good precision, which is required for environment modeling (e.g., building a Digital Elevation Map). Objects are represented by a set of 3D points, which are considered as the samples of a surface. No constraint is imposed on the form of the objects. The proposed algorithm is based on iteratively matching points in one set to the closest points in the other. A statistical method based on the distance distribution is used to deal with outliers, occlusion, appearance and disappearance, which allows us to do subsetsubset matching. A leastsquares technique is used to estimate 3D motion from the point correspondences, which reduces the average distance between points in the two sets. Both synthetic and real data have been used to test the algorithm, and the results show that it is efficient and robust, and yields an accurate motion estimate.
Practical Graph Isomorphism
, 1981
"... We develop an improved algorithm for canonically labelling a graph and finding generators for its automorph.ism grou.p. The emphasis i, on th.e power of the algorithm for,01 fling pr4ctical problem.t, rather than on the theoretical n,icetiu of tJu algo rith.m. Th.e nsult is a.n implementa.tion wh.ic ..."
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Cited by 334 (7 self)
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We develop an improved algorithm for canonically labelling a graph and finding generators for its automorph.ism grou.p. The emphasis i, on th.e power of the algorithm for,01 fling pr4ctical problem.t, rather than on the theoretical n,icetiu of tJu algo rith.m. Th.e nsult is a.n implementa.tion wh.ich011.11. 11I.ccel8/w.ly hll.ndle many grll.ph. & with. II. thot/.,1a.nd or m ore vertice~, a.nd i & ver y likely the most powerful graphisomorphism program currently in use.
Linear Inequality LTL (iLTL): A Model Checker for Discrete Time Markov Chains
 In Int. Conf. on Formal Engineering Methods. LNCS 3308
, 2004
"... We develop a way of analyzing the behavior of systems modeled using Discrete Time Markov Chains (DTMC). Specifically, we define iLTL, an LTL with linear inequalities on the pmf vectors as atomic propositions. iLTL allows us to express not only properties such as the expected number of jobs or the ..."
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Cited by 10 (6 self)
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We develop a way of analyzing the behavior of systems modeled using Discrete Time Markov Chains (DTMC). Specifically, we define iLTL, an LTL with linear inequalities on the pmf vectors as atomic propositions. iLTL allows us to express not only properties such as the expected number of jobs
Quantitative universality for a class of nonlinear Transformations
 J. Statistical Physics
, 1978
"... A large class of recursion relations xn+l = Af(xn) exhibiting infinite bifurcation is shown to possess a rich quantitative structure essentially independent of the recursion function. The functions considered all have a unique differentiable maximum 2. With f(2) f(x) ~ Ix 21 " (for Ix 21 su ..."
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Cited by 251 (0 self)
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A large class of recursion relations xn+l = Af(xn) exhibiting infinite bifurcation is shown to possess a rich quantitative structure essentially independent of the recursion function. The functions considered all have a unique differentiable maximum 2. With f(2) f(x) ~ Ix 21 " (for Ix 21 sufficiently small), z> 1, the universal details depend only upon z. In particular, the local structure of highorder stability sets is shown to approach universality, rescaling in successive bifurcations, asymptotically by the ratio c ~ (a = 2.5029078750957... for z = 2). This structure is determined by a universal function g*(x), where the 2"th iterate off, f("~, converges locally to ~"g*(~nx) for large n. For ithe class of f's considered, there exists a A ~ such that a 2"point stable limit cycle including:7 exists; A ~ ~ ~ ~ " ( ~ = 4.669201609103... for z = 2). The numbers = and have been computationally determined for a range of z through their definitions, for a variety off's for each z. We present a recursive mechanism that explains these results by determining g * as the fixedpoint (function) of a transformation on the class off's. At present our treatment is heuristic. In a sequel, an exact theory is formulated and specific problems of rigor isolated. KEY WORDS: Recurrence; bifurcation; limit cycles; attractor; universality; scaling; population dynamics.
US Army Corps II~II iltl iI]h~l of Engineers The National Study of Water Management.; During Drought Report on the First Year of Study
, 1991
"... This report is the first of a series of reports which will be published during the study. Reports on two studies conducted under the aegis of the National Study of Water Management During Drought will be published in May 1991: A Preliminary A 7ses~ment of Corps of Engineers Reservoirs, Their Purpose ..."
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This report is the first of a series of reports which will be published during the study. Reports on two studies conducted under the aegis of the National Study of Water Management During Drought will be published in May 1991: A Preliminary A 7ses~ment of Corps of Engineers Reservoirs, Their Purposes and Susceptibility t & Drought (IWR Report 91NDS2). The Corps Hydrologic Engineering C,nter in Davis, California used its Reservoir Database Network to link databases on Corps reservoirs, with databases which are maintained by other agencies for precipitation, drought, temperature, cvaporation, and streamflow, recreation, and population. Assessments were made for each Corps division. An Assessment of What is Known About Drought (IWR Report 91NDS3). Planning Management Consultants, Ltd. critically reviews reported impacts of past U.S. drought, the factors that affect vulnerability, and the current state of preparedaess throughout the U.S. The report also highlights some innovative approaches to drought preparedness throughout the U.S. that are now being used in parts responding to drought. Finally, the report suggests the areas where further research would be most productive. For firther information on the National Drought Study, contact the Study Manager:
Generalized learning vector quantization
 Hasselmo (Eds.), NIPS
, 1995
"... We propose a new learning method, "Generalized Learning Vector Quantization (GLVQ), " in which reference vectors are updated based on the steepest descent method in order to minimize the cost function. The cost function is determined so that the obtained learning rule satisfies the conver ..."
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Cited by 123 (0 self)
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We propose a new learning method, "Generalized Learning Vector Quantization (GLVQ), " in which reference vectors are updated based on the steepest descent method in order to minimize the cost function. The cost function is determined so that the obtained learning rule satisfies the convergence condition. We prove that Kohonen's rule as used in LVQ does not satisfy the convergence condition and thus degrades recognition ability. Experimental results for printed Chinese character recognition reveal that GLVQ is superior to LVQ in recognition ability. 1
iLTLChecker: A Probabilistic Model Checker for Multiple DTMCs *
"... Abstract iLTL is a probabilistic temporal logic that can specify properties of multiple discrete time Markov chains (DTMCs). In this paper, we describe two related tools:MarkovEstimator a tool to estimate a Markov transition matrix, and iLTLChecker, a tool to model check iLTL properties of DTMCs. ..."
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Abstract iLTL is a probabilistic temporal logic that can specify properties of multiple discrete time Markov chains (DTMCs). In this paper, we describe two related tools:MarkovEstimator a tool to estimate a Markov transition matrix, and iLTLChecker, a tool to model check iLTL properties of DTMCs
Bayes factors and model uncertainty
 DEPARTMENT OF STATISTICS, UNIVERSITY OFWASHINGTON
, 1993
"... In a 1935 paper, and in his book Theory of Probability, Jeffreys developed a methodology for quantifying the evidence in favor of a scientific theory. The centerpiece was a number, now called the Bayes factor, which is the posterior odds of the null hypothesis when the prior probability on the null ..."
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Cited by 121 (6 self)
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In a 1935 paper, and in his book Theory of Probability, Jeffreys developed a methodology for quantifying the evidence in favor of a scientific theory. The centerpiece was a number, now called the Bayes factor, which is the posterior odds of the null hypothesis when the prior probability on the null is onehalf. Although there has been much discussion of Bayesian hypothesis testing in the context of criticism of Pvalues, less attention has been given to the Bayes factor as a practical tool of applied statistics. In this paper we review and discuss the uses of Bayes factors in the context of five scientific applications. The points we emphasize are: from Jeffreys's Bayesian point of view, the purpose of hypothesis testing is to evaluate the evidence in favor of a scientific theory; Bayes factors offer a way of evaluating evidence in favor ofa null hypothesis; Bayes factors provide a way of incorporating external information into the evaluation of evidence about a hypothesis; Bayes factors are very general, and do not require alternative models to be nested; several techniques are available for computing Bayes factors, including asymptotic approximations which are easy to compute using the output from standard packages that maximize likelihoods; in "nonstandard " statistical models that do not satisfy common regularity conditions, it can be technically simpler to calculate Bayes factors than to derive nonBayesian significance
Results 1  10
of
806