28124507
Fast unified computation of the multi-dimensional discrete sinusoidal transforms
Based on a one-to-one index mapping approach, conversions of two types of m-dimensional discrete W transforms into the multiple sums involving a number of one-dimensional discrete W transforms (1-D DWTs) are first presented. A unified fast (m-1)-dimensional polynomial transform [(m-1)-D PT] and 1-D DWTs algorithm for computing these two types of m-D DWTs are then proposed. By revealing the relationships among the m-dimensional discrete W transforms (m-D DWTs), the m-dimensional generalized discrete Fourier transforms (m-D GDFTs), the m-dimensional discrete cosine transforms (m-D DCTs), and the m-dimensional discrete sine transforms (m-D DSTs), the generalized fast algorithms for 14 types of the m-D discrete sinusoidal transforms including four types of m-D DWTs and the same number of types of m-D GDFTs, and three types of m-D DCTs and the same number of types of m-D DSTs are presented. The number of multiplications for all 14 types of the m-D discrete sinusoidal transforms needed by the proposed algorithm is only 1/m times that of the widely used corresponding row-column methods. The number of additions required by the proposed algorithm is also reduced considerably. Finally, with the help of the software platform Visual C++ 6.0 for Windows 98, the computation time comparisons between the proposed and the reported algorithms are given. The numerical experiments show that the proposed algorithms are not only highly efficient but are also very simple in computational structure.
17770433
A generalized expansion matching based feature extractor
A novel and efficient generalized feature extraction method is presented based on the expansion matching (EXM) method and the Karhunen-Loueve (KL) transform. The EXM method is used to design optimal detectors for different features. The KL representation is used to define an optimal basis for representing these EXM feature detectors with minimum truncation error. Input images are then analyzed with the resulting KL basis set. The KL coefficients obtained from the analysis are used to efficiently reconstruct the response due to any combination of feature detectors. The method is applied to real images and successfully extracts a variety of arc and edge features as well as complex junction features formed by combining two or more arc or line features.
122560994
Fast discrete sine transform algorithms
Abstract A novel type of algorithms for the discrete sine transform (DST) are introduced in this paper. By using a basic trigonometric identity, these algorithms realize a successive reduction of the summation size in a simple manner, and therefore cause a very simple structure. The indexing of this algorithm involves the Hadamard order, the generation of which is given in this paper. These algorithms use cosines and sines as multipliers. It will cause less computational error than those algorithms with secant multipliers. The multipliers can be generated recursively in a simple way, without the need of referring to any trigonometric functions. Fortran subroutines to compute various types of the DST are provided.
207241633
A Shortest Augmenting Path Algorithm for the Semi-Assignment Problem
The objective of this study is to develop a shortest augmenting path algorithm for solving the semi-assignment problem and conduct an extensive computational comparison with the best alternative approaches. The algorithm maintains dual feasibility and complementary slackness and works toward satisfying primal feasibility. Effective heuristics arc used to achieve an excellent advanced start, and convergence is assured via the use of the shortest augmenting path procedure using reduced costs for arc lengths. Unlike other algorithms, such as the primal simplex or the auction algorithm, each iteration during the final phase of the procedure also known as the end-game achieves one additional assignment. The software implementations of our algorithm are fastest for the semi-assignment problems that we tested. Our dense code is also faster than the best software for assignment problems. In addition, the algorithm has the best polynomial worst-case running time bound that we have seen; and the memory requirements are relatively small.
5163057
The design and fabrication of welded tubular joints using solid modelling techniques
Tubular members are being used increasingly in the fabrication of welded steel structures. Because of the complexity of the joint geometry, the design and fabrication of the tubular joint by traditional methods is a time-consuming process which requires a high level of skill. This paper presents a method for the design and manufacture of tubular joints for welded structures which uses solid modelling techniques interfaced with a numerically controlled machine tool and a robot simulator. The method involves three major steps. First, a geometric model of the desired tubular joint is generated using the boundary representation solid modelling technique. Second, the geometric and topological information contained within this solid model is used along with a geometric re~oning algorithm to generate a template for the branch tube and the Computer Numerically Controlled (CNC) code required to prepare (machine) the joint groove. Finally, a simulation of the welding of the joint using an integrated welding robot and welding positioner table is performed. Geometric algorithms are used on the solid models to plan the desired welding torch trajectory for the robot and synchronized trajectory of the positioner table. In this paper, the techniques and algorithms developed to accomplish these tasks are described and examples are given to illustrate their use.
28572554
An index-based checkpointing/recovery approach for distributed systems
3937587
DC Coefficients Recovery-based Error Concealment Technique for Mpeg-2 Video Streams