• Title/Summary/Keyword: optimize

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Implementation of Scalable Video Coding method for adaptive streaming (적응 스트리밍을 위한 스케일러블 비디오 코딩 기법에 관한 연구)

  • Park, Jong-Soon;Kim, Dong-Hwan;Chang, Tae-Gyu
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.525-528
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    • 2005

  • Adaptive streaming algorithm for the realtime video decoder that can be dynamically adaptable to the network channel status or terminal environment is described and performance analyzed. An LMS filter is used to predict the bitrate and predicted bitrate is used to optimize based prediction filter is used to adapt and optimize the quality of the decoded pictures. The quality of the output pictures are about 48dB.

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Optimal Design for Reliability with Lognormally Distributed Stress and Strength (대수(對數) 정규분포(正規分布)를 하는 부하(負荷)와 강도(强度) 신뢰성(信賴性)모델에서의 최적화(最適化) 설계(設計)에 관(關)한 연구(硏究)(I))

  • Kim, Bok-Man;Hwang, Ui-Cheol
    • Journal of Korean Society for Quality Management
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    • v.18 no.2
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    • pp.43-53
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    • 1990

  • Mechanical components and structures are a major part of complex systems and the conseguences of their failure can be extremely costly. The ultimate goal of design engineers is to optimize these mechanical and structural design from the point of view of cost, reliability, weight, volume, maintainability and safety. An essential requirement of design optimization is to develop mathematical models for reliability at design stage. This paper is to minimize the cost of resources subject to the constraint that the reliability of the system must meet a specified level. The lagrange multiplier method is used to optimize the lognormal stress-lognormal strength problem. This optimization problem can be reduced to a search problem in one variable. A numerical example is presented to illustrate the optimization problem.

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Application of Surrogate Modeling to Design of A Compressor Blade to Optimize Stacking and Thickness

  • Samad, Abdus;Kim, Kwang-Yong
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.1
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    • pp.1-12
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    • 2009

  • Surrogate modeling is applied to a compressor blade shape optimization to modify its stacking line and thickness to enhance adiabatic efficiency and total pressure ratio. Six design variables are defined by parametric curves and three objectives; efficiency, total pressure and a combined objective of efficiency and total pressure are considered to enhance the performance of compressor blade. Latin hypercube sampling of design of experiments is used to generate 55 designs within design space constituted by the lower and upper limits of variables. Optimum designs are found by formulating a PRESS (predicted error sum of squares) based averaging (PBA) surrogate model with the help of a gradient based optimization algorithm. The optimum designs using the current variables show that, to optimize the performance of turbomachinery blade, the adiabatic efficiency objective is improved substantially while total pressure ratio objective is increased a very small amount. The multi-objective optimization shows that the efficiency can be increased with the less compensation of total pressure reduction or both objectives can be increased simultaneously.

  • https://doi.org/10.5293/IJFMS.2009.2.1.001 인용 PDF

Shape Optimization for Reduction of Cogging Torque in Permanent Magnet Motor by Sensitivity Analysis (영구자석전동기의 코깅토오크저감을 위한 민감도에 의한 형상최적화)

  • Park, Il-Han;Lee, Beom-Taek;Hahn, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.19-22
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    • 1990

  • In this paper, in order to reduce the cogging torque in a permanent motor, a method to optimize the shape of permanent magnet and iron pole is presented. Because the cogging torque comes from the irregular system energy variation according to the rotor position, system energy variation is taken as object function and the object function is minimized to optimize the shape. The positions of permanent magnet surface and iron pole surface are chosen as design parameters and sensitivity of object function with respect to design parameter is calculated. The shape is changed according to sensitivity. Sensitivity can be generated by methods that exploit the FEM formulation. A numerical example shows that about 90% of the original cogging torque is reduced.

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Design Technique of Post Swirl Stator in Container Vessels by CFD (CFD를 이용한 컨테이너선의 Post Swirl Stator 설계기법)

  • Kim, Ki-Hyun;Song, In-Haeng;Choi, Soon-Ho
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.2 s.152
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    • pp.93-100
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    • 2007

  • Post swirl stator is an energy saving device to recover rotational energy of the propeller. To optimize the performance of post swirl stator in container vessels, computational fluid dynamics using body force method was introduced. A commercial code Fluent was used in conjunction with body force distributed on the surface of actuator disk which is located in the propeller plane to optimize pitch angle of the post swirl stator blade. This study showed that CFD is an important tool to simulate flow behind ship with propeller, rudder and post swirl stator.

  • https://doi.org/10.3744/SNAK.2007.44.2.093 인용 PDF KSCI

Shape Optimization for Reduction of Cogging Torque in Permanent Magnet Motor by Sensitivity Analysis (영구자석전동기의 코깅토오크저감을 위한 민감도에 의한 형상 최적화)

  • 박일한;이범택;한현교;한송엽
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.12
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    • pp.1246-1252
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    • 1990

  • In order to reduce the cogging torque in a permanent magnet motor, a method to optimize the shape of permanent magnet and iron pole is presented. Sine the cogging torque comes from the irregular system energy variation according to the rotor position, system energy variation is taken as object function and the object function is minimized to optimize the shape. The positions of permanent magnet surface and iron pole surface are chosen as design parameters and sensitivity of object function with respect to the design parameter is calculated. The shape is changed according to sensitivity can be generated by methods that exploit the FEM formulation. A numerical example shows that the cogging torque is reduced to about 10% of the original value.

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Multiple Response Optimization for Robust Design using Desirability Function

  • Kwon, Yong-Man;Hong, Yeon-Woong;Chang, Duk-Joon
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.2
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    • pp.325-335
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    • 2003

  • Robust design is to identify appropriate settings of control factors that make the system's performance robust to to changes in the noise factors that represent the source of variation. In the Taguchi parameter design, the product array approach using orthogonal arrays is mainly used. However, it often requires an excessive number of experiments. An alternative approach, which is called the combined array approach, was suggested by Welch et. al. (1990) and studied by others. In these studies, only single response variable was considered. We propose how to simultaneously optimize multiple responses when we use the combined array approach.

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A Study on the Optimized Architectural Space Planning by Searching Algorithm Method (탐색적 방법에 의한 건축공간 배치계획 최적화에 대한 고찰)

  • Lim, Myung-Gu;Kim, Su-Young
    • Journal of The Korean Digital Architecture Interior Association
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    • v.1 no.1
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    • pp.51-58
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    • 2001

  • The purpose of this study is to improve productivity of architectural space planning(A.S.P,) by computer system and to optimize ASP. A searching algorithm is the best way to slave optimized A.S.P. Because architectural design is too many various site situations and client's demands to specify the general solving methods. This method seek the best design case in all possibility and to be modeled as this; $\rightarrow$[$\rightarrow$$\rightarrow$