• Fire Science and Engineering
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• v.14 no.4
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• pp.23-28
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• 2000

A performance-based design of smoke management systems for semiconductor fabrication facilities is described in this paper. The example of one such facility is discussed. Performance criteria for smoke control systems were established, effective smoke removal system features were identified and optimal system exhaust capacity requirements were developed by applying engineering tools including Fire Dynamic Simulator model. Considering the fact that the absence of relevant design guide, codes for consensus standards for semiconductor smoke design in Korea and United States this performance based approach can and should be applied to other fabrication facilities designs.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.239-245
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• 2012

This paper proposes a novel optimum design method for the PID controller of magnetic levitation-based Rail-Guided Vehicle(RGV) by a genetic algorithm using clone selection method and a new performance index function with performances of both time and frequency domain. Generally, since an attraction type levitation system is intrinsically unstable and requires a delicate controller that is designed considering overshoot and settling time, it is difficult to completely satisfy the desired performance through the methods designed by conventional performance indexes. In the paper, the conventional performance indexes are analyzed and then a new performance index for Maglev-based RGV is proposed. Also, an advanced genetic algorithm which is designed using clonal selection algorithm for performance improvement is proposed. To verify the proposed algorithm and the performance index, we compare the proposed method with a simple genetic algorithm and particle swarm optimization. The simulation results show that the proposed method is more effective than conventional optimization methods.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.377-383
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• 2007

In recent years the field application of high performance concrete has been increased to improve the quality and reliability of concrete structures. The mix design of the high performance concrete includes the 2 set-off mixture theory of mortar and coarse aggregate and that of paste and aggregate. The 2 set-off mixture theory of mortar and coarse aggregate has a problem of having to determine its value through repeated experiments in applying the rheological characteristics of mortar. The 2 set-off mixture theory of paste and aggregate has never been applied to high performance concrete since it doesn't take into account the relationship between optimum fine aggregate ratio and unit volume of powder nor does it consider the critical aggregate volume ratio. As the mixture theory of these high performance concretes, unlike that of general concrete, focuses on flowability and charge-ability, it does not consider intensity features in mix design also, the unit quantity of the materials used is determined by trial and error method in the same way as general concrete. This study is designed to reduce the frequency of trial and error by accurately calculating the optimum fine aggregate ratio, which makes it possible to minimize the aperture of aggregate in use by introducing the maximum density theory to the mix design of high performance concrete. Also, it is intended to propose a simple and reasonable mix design for high performance concrete meeting the requirements for both intensity and flowability. The mix design proposed in this study may reduce trial and error and conveniently produce high performance concrete which has self-chargeability by using more than the minimum unit volume of powder and optimum fine aggregate with minimum porosity.

• CDE review
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• v.10 no.1
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• pp.39-47
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• 2004

설계분야의 중요성은 신차 개발에 소요되는 부문별 비용들과 그들이 성능 및 생산성에 미치는 영향을 보여주는 그림 1을 통하여 명확히 설명될 수 있다. 이는 설계부문에 소요되는 비용이 다른 부문에 비해 적지만 성능 및 생산성에 미치는 영향은 지대함을 보여주며, 국내 산업체도 그 중요성을 인식하고 연구개발 투자의 비중을 높여가고 있다. 그런데, 국내 산업체의 현황을 살펴보면, 설계는 부품별 혹은 해석 분야별로 나뉘어 여러 설계부서들에서 이루어지며, 결과를 종합하는 단계에서 서로 상충되는 결과가 나타나면 관리자의 판단이나 부서간 협의에 의하여 재 설계하는 과정을 반복한다. (중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.246-249
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• 2003

The propeller of the propulsion system for a target drone has been designed. Vortex theory has been applied to the propeller design method. This method analyze the propeller performance according to the design parameters. The optimum design has been aimed to maximize the efficiency. The performance of the designed propeller has been analyzed.

• The KSFM Journal of Fluid Machinery
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• v.12 no.5
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• pp.61-65
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• 2009

현재 선진업체들은 성능과 구조적으로 경쟁력 있는 산업용 가스터빈 압축기를 설계하기 위하여 항공기용 압축기 설계기술을 전용하고 있다. 따라서 두산중공업은 DGT-5 압축기 익형설계를 위해 항공용 익형설계에 적용되는 S-Profile 설계기술을 활용하여 설계하였으며 현재 DGT-5 압축기에 대한 1차 성능시험이 완료되어 만족할 만한 결과를 얻었다. 그리고 DGT-5 압축기는 추후 두산중공업 파생형 가스터빈 압축기의 기본압축기로 활용할 계획이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.796-799
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• 2004

최근 반도체 기술과 회로 설계 기술이 발달하면서, 하드웨어와 소프트웨어 부분을 별도로 분리하여 설계하지 않고, 통합하여 설계함으로써 적은 비용으로 고성능의 시스템을 구축할 수 있는 통합설계 기반이 구축되었다. 그러나, 하드웨어와 소프트웨어가 혼재할 경우에는 두 영역 사이에서의 통신 부담이 비교적 큰 편으로 발생하여 오히려 소프트웨어로만 설계한 경우보다 성능이 떨어질 소지가 있다. 본 논문에서는 이러한 통신 부담을 줄일 수 있는 방안에 대해 세 가지를 간략히 소개하고 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.193-200
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• 2010

Structural design requires simultaneously to ensure safety by considering quantitatively uncertainties in the applied loadings, material properties and fabrication error and to maximize economical efficiency. As a solution, system reliability-based design optimization (SRBDO), which takes into consideration both uncertainties and economical efficiency, has been extensively researched and numerous attempts have been done to apply it to structural design. Contrary to conventional deterministic optimization, SRBDO involves the evaluation of component and system probabilistic constraints. However, because of the complicated algorithm for calculating component reliability indices and system reliability, excessive computational time is required when the large-scale finite element analysis is involved in evaluating the probabilistic constraints. Accordingly, an algorithm for SRBDO exhibiting improved stability and efficiency needs to be developed for the large-scale problems. In this study, a more stable and efficient SRBDO based on the performance measure approach (PMA) is developed. PMA shows good performance when it is applied to reliability-based design optimization (RBDO) which has only component probabilistic constraints. However, PMA could not be applied to SRBDO because PMA only calculates the probabilistic performance measure for limit state functions and does not evaluate the reliability indices. In order to overcome these difficulties, the decoupled algorithm is proposed where RBDO based on PMA is sequentially performed with updated target component reliability indices until the calculated system reliability index approaches the target system reliability index. Through a mathematical problem and ten-bar truss problem, the proposed method shows better convergence and efficiency than other approaches.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.371-377
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• 2000

This paper deals with the design techniques for underwater acoustic basin. An underwater acoustic basin is needed for test and calibration of acoustic sensors, acoustic digital communication system, acoustic measurement system, and underwater image data telemetry system. KRISO(Korea Research Institute of Ships and Ocean Engineering) have planned the construction of an underwater acoustic tank from 1999 to 2001 through internal project. We studied about absorbtion characteristics of a porous re-cycled rubber which is selected as a absorption materials and designed absorption plate with wedge shape. The simulation of reflection analysis along the wedge angle for wedged type plate was presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.401-405
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• 2010

An efficient performance model for scramjet engines has been proposed for scramjet performance design. In supersonic air intake design, the compression angles of the wedge were determined to maximize the total pressure recovery of the intake based on Oswatisch criterion. Both combustion models of chemical equilibrium and finite-rate chemistry model are implemented, and compared each model with the results by Starkey for Waverider engine configuration. Finally, the performance model of concern has been confirmed by conducting performance analysis with hypothetical mission profile and design conditions.