In this research, some novel modifications and modern applications of the Hough transform algorithms have been pursued. First, the dual points Hough transform algorithm was studied. Our approach optimises the R-Table ...
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In this research, some novel modifications and modern applications of the Hough transform algorithms have been pursued. First, the dual points Hough transform algorithm was studied. Our approach optimises the R-Table of the prototype by using some statistics techniques in order to reduce the number of entries per index in the R-Table and make the entries inside the R-Table distribute evenly. Experimental results show that our method can both speed up the process and increase the recognition accuracy. Second, a dominant point detection algorithm has also been studied. The reason for pursuing this study is that we can reduce the number of operations by employing dominant points as the features in the Hough transform process. Owing to the lack of appropriate dominant point detection algorithms for real scenes, a new dominant point detection algorithm has been proposed. Apart from the curvature points, we also defined the termination and intercept points on a digital curve as the dominant points since they indeed give useful information about the natures of the curves. A weighted mask is proposed for the initial detection. By using a look up table, all possible dominant points can be located efficiently. Experimental results show that our method achieves a better performance in terms of approximation error when compared with other methods. After the development of the dominant point detection algorithm, we have developed a Hough transform algorithm that makes use of the dominant points as the corresponding features in tracking an object in a video sequence. The user inputs a user-defined object in the first frame. Then, an R-Table is built based upon the dominant points of the selected object. When the next frame is reached, the transformation parameters of the object can then be detected by using the Hough transform. Our proposed algorithm is capable not only to track the object under a continuous deformation, but also able to recognise the object under occlusion and r
The number of spanning trees in a (di-)graph (network) is an important, well-studied quantity. Most research about the number of spanning trees is devoted to determining exact formulae for the number of spanning trees...
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The number of spanning trees in a (di-)graph (network) is an important, well-studied quantity. Most research about the number of spanning trees is devoted to determining exact formulae for the number of spanning trees in many kinds of special graphs. In this thesis, we start by stating the general methods for counting the number of spanning trees in (di-)graphs. We then discuss our new results. We show that the number of spanning trees in the circulant graph [special characters omitted] always satisfies a recurrence relation and describe how to derive this relation. The asymptotic behavior of these quantities are also derived. Boesch and Prodinger have shown how to use Chebyshev polynomials to derive closed formulae for the number of spanning trees of graphs in certain classes. This work has been extended to develop new techniques for the evaluation of the number of spanning trees in circulant graphs and graphs related to circulant graphs. We end by describing a method of counting the number of spanning trees in one class of double fixed-step loop networks.
In this paper we consider various aspects of parallel realization of the Monte Carlo method algorithms on multiprocessor computation systems. In particular, we consider the distribution of 'statistical tests' ...
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In this paper we consider various aspects of parallel realization of the Monte Carlo method algorithms on multiprocessor computation systems. In particular, we consider the distribution of 'statistical tests' among various processors and the correlation of the corresponding results with the aim to effectively estimate functional relationships in the metric C. We developed the modification of an 'astronomically' long-period 'congruential' program pseudorandom number generator. It allows us to effectively distribute generated numbers essentially among an arbitrary number of processors. We conducted multidimensional uniformity tests for the modified generator by the 'chi-square' criterion to the seventh dimension. All the tests gave satisfactory results. The corresponding computational routines in Fortran 90 are given in the Section 4.
The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of s...
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The development of intelligent transportation systems (ITS) and the resulting need for the solution of a variety of dynamic traffic network models and management problems require faster-than-real-time computation of shortest path problems in dynamic networks. Recently, a sequential algorithm was developed to compute shortest paths in discrete time dynamic networks from all nodes and all departure times to one destination node. The algorithm is known as algorithm DOT and has an optimal worst-case running-time complexity. This implies that no algorithm with a better worst-case computational complexity can be discovered. Consequently, in order to derive algorithms to solve all-to-one shortest path problems in dynamic networks, one would need to explore avenues other than the design of sequential solution algorithms only. The use of commercially-available high-performance computing platforms to develop parallel implementations of sequential algorithms is an example of such avenue. This paper reports on the design, implementation, and computational testing of parallel dynamic shortest path algorithms. We develop two shared-memory and two message-passing dynamic shortest path algorithm implementations, which are derived from algorithm DOT using the following parallelization strategies: decomposition by destination and decomposition by transportation network topology. The algorithms are coded using two types of parallel computing environments: a message-passing environment based on the parallel virtual machine (PVM) library and a multi-threading environment based on the SUN Microsystems Multi-Threads (MT) library. We also develop a time-based parallel version of algorithm DOT for the case of minimum time paths in FIFO networks, and a theoretical parallelization of algorithm DOT on an ‘ideal’ theoretical parallel machine. Performances of the implementations are analyzed and evaluated using large transportation networks, and two types of parallel computing platforms: a distr
Let M and P be Seifert 3-manifolds. Is there a degree one map f : M --> P ? The problem was completely solved by Hayat-Legrand, Wang, and Zieschang for all cases except when P is the Poincare homology sphere. We in...
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Let M and P be Seifert 3-manifolds. Is there a degree one map f : M --> P ? The problem was completely solved by Hayat-Legrand, Wang, and Zieschang for all cases except when P is the Poincare homology sphere. We investigate the remaining case by elaborating and implementing a computer algorithm that calculates the degree. As a result, we get an explicit experimental expression for the degree through numerical invariants of the induced homomorphism f(#) : pi(1)(M) --> pi(1)(P).
For a large number of degrees of freedom and/or large dimension systems, non-linear model based predictive control algorithms based on dual mode control can become intractable. This paper proposes an alternative which...
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For a large number of degrees of freedom and/or large dimension systems, non-linear model based predictive control algorithms based on dual mode control can become intractable. This paper proposes an alternative which deploys the closed-loop paradigm that has proved to be very effective for the case of linear time-varying or uncertain systems. The various attributes and computational advantages of the approach are shown to carry over to the non-linear case.
The current technology manifests a great demand for high precision and high positioning accuracy in many engineering applications that range from robot manipulators and high-speed flexible mechanisms to supercritical ...
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The current technology manifests a great demand for high precision and high positioning accuracy in many engineering applications that range from robot manipulators and high-speed flexible mechanisms to supercritical rotors and the space deployable structures. Active control is an important technique for suppressing vibrations in flexible mechanical systems where passive controllers may become either ineffective or impractical. A finite element model of the system dynamics in conjunction with modal reduction methods is introduced. The developed model accounts for the structural material damping. Pointwise observation and control are implemented using two sets of sensors and actuators, respectively. The developed computational active modal control algorithm is applied to the reduced order model of a double span elastic beam, and the dynamic responses of both the controlled and the residual frequency subsystems are numerically evaluated. (C) 2001 Elsevier Science B.V. All rights reserved.
The problem of texture mapping on real world objects has attracted attention(11,8) recently. A work by Lensch et al.(9) addressed the problem of locating a camera position in the celestial sphere and then mapping the ...
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The problem of texture mapping on real world objects has attracted attention(11,8) recently. A work by Lensch et al.(9) addressed the problem of locating a camera position in the celestial sphere and then mapping the acquired pictures on a real world object. The entire process took a half hour to one hour to map 10 to 15 pictures. In this paper we propose a new innovative algorithm to speed up the texture mapping or painting process in real-time. We built a PC-based system using a commonly available video card with a geometry engine. Mapping of a picture required about 20 seconds. It is successful in giving an illusion to the operator to paint a colorless real world object with a color texture brush.
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