• Progress in Superconductivity and Cryogenics
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• v.23 no.4
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• pp.39-43
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• 2021

This study deals with the ferromagnetic shims design based on the spherical harmonic coefficient reduction method. The design method using the sequential search method is an intuitive method and has the advantage of quickly reaching the optimal result. The study was conducted for a 400 MHz all-REBCO magnet, which had difficulty in shimming due to the problem of SCF (screening current induced field). The initial field homogeneity of the magnet was measured to be 233.76 ppm at 20 mm DSV (Diameter Spherical Volume). In order to improve the field homogeneity of the magnet, the ferromagnetic shim with a thickness of 1 mil to 11 mil was constructed by a design method in which sequential search algorithm was applied. As a result, the field homogeneity of the magnet could be significantly improved to 0.24 ppm at 20 mm DSV and 0.05 ppm at 10 mm DSV.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.180-192
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• 2000

Recently, the component technology has played a main role in software reuse. It has changed the code-based reuse into the binary code-based reuse, because components can be easily combined into the developing software only through component interfaces. Since components and component users have increased rapidly, it is necessary that the users of components search for the most proper components for HTML among the enormous number of components on the Internet. It is desirable to use web-document-typed specifications for component specifications on the Internet. This paper proposes to use XML component specifications instead of HTML specifications, because it is impossible to represent the semantics of contexts using HTML. We also propose the XML context-search method based on XML component specifications. Component users use the contexts for the component properties and the terms for the values of component properties in their queries for searching components. The index structure for the context-based search method is the inverted file indexing structure of term-context-component specification. Not only an XML context-based search method but also a variety of search methods based on context-based search, such as keyword, search, faceted search, and browsing search method, are provided for the convenience of users. We use the 3-layer architecture, with an interface layer, a query expansion layer, and an XML search engine layer, of the search engine for the efficient index scheme. In this paper, an XML DTD(Document Type Definition) for component specification is defined and the experimental results of comparing search performance of XML with HTML are discussed.

• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.29-34
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• 1999

To develop the efficient numerical optimization method for the design of an airfoil, an evaluation of various methods coupled with two-dimensional Naviev-Stokes analysis is presented. Simplex method and Hook-Jeeves method we used as direct search methods, and steepest descent method, conjugate gradient method and DFP method are used as indirect search methods and are tested to determine the search direction. To determine the moving distance, the golden section method and cubic interpolation method are tested. The finite volume method is used to discretize two-dimensional Navier-Stokes equations, and SIMPLEC algorithm is used for a velocity-pressure correction method. For the optimal design of two-dimensional airfoil, maximum thickness, maximum ordinate of camber line and chordwise position of maximum ordinate are chosen as design variables, and the ratio of drag coefficient to lift coefficient is selected as an objective function. From the results, it is found that conjugate gradient method and cubic interpolation method are the most efficient for the determination of search direction and the moving distance, respectively.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.707-719
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• 2018

In this article, a new method is introduced to improve the local search capability of meta-heuristic algorithms using the projection of the path on the border of constraints. In a mathematical point of view, the Gradient Projection Method is applied through a new approach, while the imposed limitations are removed. Accordingly, the gradient vector is replaced with a new meta-heuristic based vector. Besides, the active constraint identification algorithm, and the projection method are changed into less complex approaches. As a result, if a constraint is violated by an agent, a new path will be suggested to correct the direction of the agent's movement. The presented procedure includes three main steps: (1) the identification of the active constraint, (2) the neighboring point determination, and (3) the new direction and step length. Moreover, this method can be applied to some meta-heuristic algorithms. It increases the chance of convergence in the final phase of the search process, especially when the number of the violations of the constraints increases. The method is applied jointly with the authors' newly developed meta-heuristic algorithm, entitled Star Graph. The capability of the resulted hybrid method is examined using the optimal design of truss and frame structures. Eventually, the comparison of the results with other meta-heuristics of the literature shows that the hybrid method is successful in the global as well as local search.

• Journal of Broadcast Engineering
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• v.22 no.2
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• pp.240-252
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• 2017

Multi-view video codec based on the High Efficiency Video Coding (MV-HEVC) has high encoding complexity because it exploits an additional reference picture for disparity compensation prediction (DCP) when the picture of dependent view is encoded. In this paper, we propose an efficient method to reduce the complexity of disparity motion vector search for the MV-HEVC. The proposed method includes the initial search point decision method using affine transform and the adaptive search range decision method. The simulation results show that the proposed method reduces the complexity of disparity motion vector search up to 90.78% with negligible coding efficiency degradation. Also the results show that the proposed method outperforms other conventional techniques reducing complexity.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.1-7
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• 2023

In this paper, we propose a base address candidate selection method using the $gp register and page granularity as a way to build a static analysis environment for firmware based on MIPS architecture. As a way to shorten the base address search time, which is a disadvantage of the base address candidate selection method through inductive reasoning in existing studies, this study proposes a method to perform page-level search based on the $gp register in the existing base address candidate selection method as a reference point for search. Then, based on the proposed method, a base address search tool is implemented and a static analysis environment is constructed to prove the validity of the target tool. The results show that the proposed method is faster than the existing candidate selection method through inductive reasoning.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.333-341
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. Multi-view video coding requires high computational complexity. To reduce computational complexity and maintain the image quality, an effective early termination motion estimation method is proposed in this paper. The proposed method exploiting the characteristic of motion vector distribution uses a hierarchical search strategy. This strategy method consists of multi-grid square search pattern, modified diamond search pattern, small diamond search pattern and raster search pattern. Experiment results show that the speedup improvement of the proposed method over TZ search method and FS(Full Search) method JMVC (Joint Multiview Video Coding) can be up to 1.7~4.5 times and 90 times faster respectively while maintaining similar video quality and bit rates.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.369-378
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• 2012

In this study, direct-search based optimization methods are applied for blade shape optimization of wind turbines and the optimization performances of several methods including conventional genetic algorithm, micro genetic algorithm and pattern search method are compared to propose a more efficient method. For this purpose, the currently available version of HARP_Opt (Horizontal Axis Rotor Performance Optimizer) code is enhanced to rationally evaluate the annual energy production value according to control strategies and to optimize the blade shape using pattern search method as well as genetic algorithm. The enhanced HARP_Opt code is applied to obtain the optimal turbine blade shape for 1MW class wind turbines. The results from pattern search method are compared with the results from conventional genetic algorithm and also micro genetic algorithm and it is found that the pattern search method has a better performance in achieving higher annual energy production and consistent optimal shapes and the micro genetic algorithm is better for reducing the calculation time.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1380-1382
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• 1996

In this paper, a motion estimation module is made with ADSP-21020 based on MPEG-2 which is an international standard for moving picture compression. And, the block matching algorithm used as motion estimation method is easy for an hardware implementation. The ADSP-21020 of Analog Device is used for a main control processor. We used three block matching method (exhaustive search method, 2D-logarithmic search method, three step search method) for software simulation and implemented the three step search method to hardware. For the test of the estimation module, we used ping pong image sequences and mobile and calendar image sequences.

• IE interfaces
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• v.18 no.4
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• pp.504-511
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• 2005

The NP-hard channel assignment problem becomes more and more important to use channels as efficiently as possible because there is a rapidly growing demand and the number of usable channel is very limited. The hybrid genetic and local search (HGLS) method in this paper is a hybrid method of genetic algorithm with no interference channel assignment (NICA) in clustering stage for diversified search and local search in tuning stage when the step of search is near convergence for minimizing blocking calls. The new representation of solution is also proposed for effective search and computation for channel assignment.