• Title/Summary/Keyword: optimal experimental design

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A Development of Multi-Stage Sequence Dependent Flowshop Scheduling Heuristics (준비시간이 작업순서에 영향을 받는 흐름작업에서의 휴리스틱 알고리즘)

  • Choe, Seong-Un;No, In-Gyu
    • Journal of Korean Society for Quality Management
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    • v.17 no.2
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    • pp.121-141
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    • 1989
  • This paper is concerned with a development and evaluation of heuristics for the multi-stage sequence dependent flowshop sequencing. Eighteen heuristics, CAM1, CAM2, and etc., are proposed. The performance measure is a makespan which is to be minimized. The experiment for each algorithm is designed for a 4*3*3 factorial design with 360 observations. The experimental factors are PS(ratio of processing times to setup times), M(number of machines), N(number of jobs). The makespan of the proposed heuristics is compared with the optimal makespan obtained by the complete enumeration of schedules. This yardstick of comparison is called a relative error. The mean relative errors of the eighteen heuristics are from 2.048% to 8.717%. The computational results are analysed using SPSS. The experimental results show that the three factors are statistically significant at 5% level. The simulation for the large size problems is conducted to show having the similar computational results like the small size problems.

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Dynamic characteristics indentification of automobile exhaust system and determination of hanger optimal position (자동차 배기계의 동특성 규명 및 행거 최적위치의 결정)

  • 오재응;임동규;조준호;김만복
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.57-70
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    • 1992
  • As automobile industry develope, design techniques to satisfy light weight and high efficiency in automobile parts is demanded. In this study modal analysis is performed using transfer matrix method to identify dynamic characteristics of exhaust system. It is estimated the theoretical transfer function by Pestel-Leckey method and the mode shapes in 3-D graphic. the validity of developed program is verified by comparing with the experimental results of exhaust system. Estimated modal parameters(natural frequency, vibrational mode, transfer function) are in accord with the experimental results. From the developed program, we can predict a location of the hanger which is determined by the lowest RMS value point, when displacement is given as an input at the engine side. We can find that attachment of spring modelled hanger at the hanger location bring vibration level down.

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Structural analysis of $Al_{x}Ga_{1-x}As/In_{y}Ga_{1-y}$As P-HEMTs reverse engineering (Reverse Engineering을 이용한 $Al_{x}Ga_{1-x}As/In_{y}Ga_{1-y}$As P-HEMTs의 구조적 분석)

  • 김병헌;황광철;안형근;한득영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.255-258
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    • 2001
  • In this paper, DC and small signal characteristics with different physical parameters are expected for p-HEMTs (Pseudomorphic High Electron Mobility Transistors) with different temperatures ranging from 300K to 623K which are widely used for a low noise and/or ultra high frequency device. A device of 0.2$\times$200 ${\mu}{\textrm}{m}$$^2$dimension having very low noise has been chosen to extract the experimental data. Theoretical prediction has been obtained using a simulaor(HELENA) which needs experimental input data extracted from reverse engineering process. From the results, relation between structural parameters and temperature dependency of electrical characteristics are qualitatively explained to use in the design of descrete and integrated circuits to guarantee the optimal operation of the system.

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반응표면 분석법을 이용한 광학활성 styrene oxide의 생산조건 최적화

  • Lee, Eun-Yeol;Yun, Seong-Jun;Bae, Hyeon-Cheol;Gang, Jin-Hui
    • 한국생물공학회:학술대회논문집
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    • 2000.11a
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    • pp.593-596
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    • 2000
  • Chiral epoxides are useful chiral synthons in organic synthesis and various biological methods have been investigated for the production of chiral epoxides. In this work, enantioselective resolution of racemic styrene oxide was investigated using an isolated Aspergillus niger sp. for the production of optically pure (S) -styrene oxide. The enantioselectivity and initial hydrolysis rates of racemic substrate were highly dependent on the pH, temperature, and the volume ratio of cosolvent. The experimental sets of pH, temperature, and the volume ratio of cosolvent were designed using central composite experimental design, and the reaction conditions were optimized using response surface analysis. The optimal conditions of pH, temperature, and the volume ration of cosolvent were determined to be 7.78, $28.32^{\circ}C$, and 2.4 %(v/v), respectively, and optically pure (S)-styrene oxide (> 99% ee) could be obtained with the 35 % yield by microbial enantioselective hydrolysis reaction.

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Numerical and Experimental Studies for the Design of High Efficiency Sedimentation Bed (고효율 침전조 설계를 위한 실험 및 수치해석)

  • Kim, Hong-Min;Choi, Sang-Cheol;Kim, Kwang-Yong;Kim, Byung-Hee;Lim, Young-Taek
    • The KSFM Journal of Fluid Machinery
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    • v.6 no.2 s.19
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    • pp.54-61
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    • 2003
  • Both numerical and experimental studies on the sedimentation efficiency of a sedimentation bed were carried out. Three different structures of sedimentation bed and five different combinations of blockage ratio of center feed wall and angle of distributor are implemented to find the optimal values of geometric parameters. The effect of rotation of the distributor on sedimentation efficiency is also investigated. It reveals that the effects of blockage ratio and angle of distributor on sedimentation efficiency are considerable, while rotation effect can be neglected, and that calculated efficiencies show good agreements with those of experiment, qualitatively.

An Experimental Study for the 77K Inertance Tube Pulse Tube Cryocooler (77K Inertance tube 맥동관 극저온 냉동기에 관한 연구)

  • Park, Seong-Je;Go, Deuk-Yong;Kim, Hyo-Bong
    • 연구논문집
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    • s.29
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    • pp.17-27
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    • 1999
  • The experimental results of the 17K inertance tube pulse tube cryocooler for cooling cryosensors are presented in this paper. In prototype experiments, linear compressor is driven by linear motor, and inertance tubes are inserted between one liter reservoir and pulse tube. Design of the inertance tube pulse tube cryo-cooler is conducted by ARCOPTR program of NASA Ames Research Center. To find optimal conditions of inertance tube pulse tube cryocooler, no load temperature and refrigeration capacity according to the variations of inertance tube volume, reservoir volume and charging pressure are measured. and the cool down and load characteristics at the particular conditions are presented. As the representative results, no load temperature of the cold end is 52.7K and refrigeration capacity is 5W at 72K..

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Selection of Centrifugal Fan for Flows with Down-Stream Resistance (유동 저항에 따른 원심홴의 선정)

  • Kim Jae-Won;Jang Dong-Hee;Ahn Eun-Young
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.3 s.36
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    • pp.44-48
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    • 2006
  • Comprehensive experimental works are carried out for the optimal design of a centrifugal blower adopted in an indoor unit of an air-conditioner. The models for consideration are typical multi-blade turbo blower and limit loaded one, respectively. The main interest lies on the fluid dynamics performance when the blower Is installed in the practical system. The methodologies are an experimental estimations with a wind tunnel for blower performance and PIV measurement for the detail flow information. A centrifugal blower with limit loaded fan shows pronounced performances in terms of the flow rate and static pressure rise and the reason is explained by the precise measurement of the flows between blades using PIV. Consequently, it is found that the blower is proper for the flows with a resistance in down stream such as a heat exchanger.

Performance Optimization of Hypervelocity Launcher System using Experimental Data

  • Huh, Choul-Jun;Lee, Jin-Ho;Bae, Ki-Joon;Jeon, Kwon-Su;Byun, Yung-Hwan;Lee, Jae-Woo;Lee, Chang-Jin
    • Journal of Mechanical Science and Technology
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    • v.18 no.10
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    • pp.1829-1836
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    • 2004
  • This study presents the performance optimization of hypervelocity launcher system by using the experimentall data. During the optimization, the RSM (Response Surface Method) is adopted to find the operating parameters that could maximize the projectile speed. To construct a reliable response surface model, 3 full factorial method is used with the selected design variables, such as piston mass and 2 driver fill pressure. Nine test data could successfully construct the reasonable response surface, which used to yield the optimal operational conditions of the system using the genetic algorithm. The optimization results are confirmed by the experimental test with a good accuracy. Thus, the optimization can improve the performance of the facility.

A Development of Heuristic Algorithms for the Multi-stage Manufacturing Systems with Sequence Dependent Setup Times (준비시간이 종속적인 n/M 스케쥴링 문제의 휴리스틱 알고리듬(I))

  • Choe, Seong-Un;No, In-Gyu
    • Journal of Korean Society for Quality Management
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    • v.17 no.1
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    • pp.35-47
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    • 1989
  • This paper is concerned with a development and evaluation of heuristic algorithms for the n-job, M-stage flowshop with sequence dependent setup times. Three heuristic algorithms, CAIDAN, DANNEN and PETROV, are proposed. The makespan is taken as a performance measure for the algorithms. The experiment for each algorithm is designed for a $4{\times}3{\times}3$ factorial design with 360 observations. The experimental factors are PS (ratio of processing times to setup times), M (number of machines), and N (number of jobs). The makespan of the proposed heuristic algorithms is compared with the optimal makespan obtained by the complete enumeration method. The result of comparision of performance measure is called a relative error. The mean relative errors of CAIDAN, DANNEN and PETROV algorithms are 4.488%. 6.712% and 7.282%, respectively. The computational results are analysed using SPSS. The experimental results show that the three factors are statistically signiticant at 5% level.

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Quality Improvement of Machined Surface in MQL Machining (MQL 가공에서 기계가공면의 표면 품위 향상)

  • Jung, Jong-Yun;Cho, Hyung-Chan;Lee, Choon-Man
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.30 no.3
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    • pp.54-61
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    • 2007
  • Machining processes produce high accurate metallic parts in metal working industries. Lubrication for machining enhances quality of machined surface and it prolongs the life of cutting tools. Since lubricant is poisonous to human body and environment, it causes occupational diseases for workers and air pollution in environment. Because of these problems generated, developed countries do not permit the excessive usage of lubricant in machining shops. This research focuses on the development of MQL machining technique that consumes minimal amount of lubricant, which reduces possible outbreak of occupational diseases and air pollution. This research sets experimental equipments for MQL machining. Experiments for this study are designed with major machining parameters in MQL. Through the analysis of experiments, this paper presents the optimal machining parameters.