• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.811-816
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• 2011

In this paper, we propose a optimal design using the Evolution Strategy of a high gain $4\times4$ array antenna that have the resonant frequency of a 19.05GHz with 18.86GHz~19.26GHz bandwidth. The proposed array antenna structure is designed to be allocated equally electric power by microstrip patch power splitter. Thus the optimal array antenna with power splitter are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The simulation result of $4\times4$ array antenna is confirmed that the Gain is 19.36 dBi at resonance frequency 19.05GHz.

• Journal of the Korea Society of Computer and Information
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• v.14 no.7
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• pp.1-8
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• 2009

In this paper, make a study decision problem called an optimal release policies after testing a software system in development phase and transfer it to the user. The optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement is generally accepted. The Bayesian parametric inference of model using log Poisson execution time employ tool of Markov chain(Gibbs sampling and Metropolis algorithm). In a numerical example by T1 data was illustrated. make out estimating software optimal release time from the maximum likelihood estimation and Bayesian parametric estimation.

• Journal of Mechanical Science and Technology
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• v.14 no.9
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• pp.947-955
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• 2000

This paper proposes an optimal design scheme to improve the muffler's capacity of noise reduction of the exhaust system by combining the Taguchi method and a fractional factorial design. As a measuring tool for the performance of a muffler, the performance prediction software which is developed by Oh, Lee and Lee (1996) is used. In the first stage of a design, the length and radius of each component of the current muffler system are selected as control factors. Then, the $L_{18}$ table of orthogonal arrays is adopted to extract the effective main factors. In the second stage, the fractional factorial design is adopted to take interactions into consideration, which the $L_{18}$ table of orthogonal arrays can not consider. For an optimal design, the $L_{27}$ table of orthogonal arrays with main and interaction effects is proposed and the noise factors such as temperature, background noise and humidity are analyzed for more efficient design simultaneously.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.172-177
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• 2004

A planetary gear trains has characteristics in compactness, power transformation ability and constant meshing. Usability is increased in applications of auto transmission and industrial gearbox. Study on optimum design of planetary gear train has been progressed on minimization of weight, miniaturization of planetary gear train and improvement of high strength. There are demands of study for the planetary gear train required long lift estimation In this wort being considered life, strength, intereference, contact ratio and aspect ratio, the optimum design algorithm is proposed to reduce the volume of planetary gear train with transferring the same amount of power. In the design of algorithm for planetary gear train, the determination of teeth number is separated to achieve simplicity and the simulated annealing method as a global optimal technique is used for optimal design method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.276-277
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• 2008

Recently active engine mounting system is developed for improvement of vehicle NVH performance which follow the development of high efficient powertrain and lightweight vehicle body. The most important part in the development of active engine mounting system is implementation of optimal engine mounting system to apply active engine mount. In this paper engine mounting systems including active engine mount are considered and their performance is predicted using engine mounting system analysis tool. Then optimal mounting system for active engine mount is proposed.

• Transactions of Materials Processing
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• v.11 no.4
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• pp.363-370
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• 2002

In this study, an optimal design technique was investigated for determining appropriate dimensions of components of the die set used in the extrusion process. For this, an axi-symmetric elastic finite element program for the analysis of deformation of the shrink fitted die set was developed with the Lagrange multiplier method to implement the constraint condition of shrink fit of stress ring. By coupling the rigid-viscoplastic analysis of extrusion process by CAMPform and elastic analysis of the die set, the optimization study was made by employing optimization program DOT. Considering the various assembly conditions, optimal design was determined for a single stress ring case. It is construed that the proposed design method can be beneficial for improving the tool life of cold extrusion die set at practice.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.96-102
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• 2007

An Optimal shape design of the boom system in high ladder vehicles is performed using 3-D finite element method (FEM). Results of structural analyses providing displacements, stresses are implemented for the optimum shape design. Lanzcos algorithm is used for the modal analysis in order to find natural frequencies. The optimal shape including cross sectional thickness and length of the boom system is controlled by the subproblem method besed on displacement and Von Mises stress. It is found that a plenty of materials can be saved by using shape design optimization in high ladder vehicles. It is also found that the natural frequency is increased until 6th mode and maintained similarly or decreased after 6th mode.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.38-45
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• 2006

In this work, optimal finish machining condition considering total time for mold or electrode manufacturing was investigated. First, manual finishing time according to the machining condition was analyzed for the work material. The effect of runout and phase shift of tool path on surface finish was also considered in those analyses. Secondly, optimal manual finishing processes were determined for various machining conditions. Finally, finish machining time and corresponding manual finishing time were taken into account for the estimation of the total time of manufacturing mold. Though small feed per tooth and pick feed reduced the manual finishing time, the finish machining time increased in such conditions. With a machining condition of feed per tooth of 0.2 mm and pick feed of 0.3 mm, the minimum total time of manufacturing mold was achieved in our machining condition.

• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.106-118
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• 2007

This paper present a new optimization model to generate aggregate production planning by considering electric cost. The new Time Of Switching (TOS) electric type is introduced by switching over Time Of Day (TOD) and Time Of Use (TOU) electric types to minimize the electric cost. The fuzzy demand and Dynamic inventory tracking with multiple plant capacity are modeled to cover the uncertain demand of customer. The constraint for minimum hour limitation of plant running per one start up event is introduced to minimize plants idle time. Furthermore; the Optimal Weight Moving Average Factor for customer demand forecasting is introduced by monthly factors to reduce forecasting error. Application is illustrated for multiple cement mill plants. The mathematical model was formulated in spreadsheet format. Then the spreadsheet-solver technique was used as a tool to solve the model. A simulation running on part of the system in a test for six months shows the optimal solution could save 60% of the actual cost.

• Transactions of Materials Processing
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• v.10 no.6
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• pp.493-499
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• 2001

An optimal robust design methodology has been developed to minimize warpage in injection-molded pats. The response surface methodology was applied to obtain a functional relationship between design variables and warpage value, and the modified complex method was used as an optimization tool to search for an optimal design solution over prescribed design region. To attain robustness against process variations, Taguchi's SN ratio was introduced as the design metric. The proposed optimal design procedure was applied to an actual part, the Guide-ASF model of a fax machine, and the usefulness of the methodology was shown through the CAE simulation using a commercial injection molding software package.