• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1022-1027
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• 2004

In this study, the shape of plate-fin type heat sink is numerically optimized to acquire the minimum pressure drop under the required temperature rise. To do this, a new sequential approximate optimization (SAO) is proposed and it is integrated with the computational fluid dynamics (CFD). In thermal/fluid systems for constrained nonlinear optimization problems, three fundamental difficulties such as high cost for function evaluations (i.e., pressure drop and thermal resistance), the absence of design sensitivity information, and the occurrence of numerical noise are confronted. To overcome these problems, the progressive quadratic response surface method (PQRSM), which is one of the sequential approximate optimization algorithms, is proposed and the heat sink is optimize by means of the PQRSM.

• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.275-281
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• 1993

The new high temperature plasma source for spectrochemical analysis has been developed and characterized. In the development of new high temperature plasma sources for atomic emission spectrocopy, optimization of experimental variables is necessary to achieve the best analytical results. By means of a modified sequential simplex optimization method, six experimental variables were optimized. The line-to-background (L/B) ratio for Ca(II) at 393.37 nm was used as measure of the response function. The optimal experimental conditions were found to be at a current of 27.8 A, a plasma length of 28.8 mm, a sample uptake rate of 1.3 ml/min, a sample carrier gas flow rate of 0.7 ml/min, a plasma gas flow rate of 4.9 l/min, and an observation height of 6.4 mm above the top quartz tube.

• 동력기계공학회지
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• 제18권3호
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• pp.20-28
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• 2014

Most washing machines are now produced as a drum-type, where a washing drum mounted on a suspension system with springs and dampers, to minimize the transmittance of the vibration from the drum to the cabinet. The purpose of this paper is to develop optimized suspension system of the drum washing machine which minimizes transmission of disturbing vibration and force. In this paper, a method for optimizing suspension system of the drum washing machine is presented using ADAMS. The design variables to optimize are extracted using Sequential Quadratic Programming(SQP) in ADAMS. To evaluate optimized spring constants and damping coefficients of the drum washing machine, simulation was done to compare the vibration attenuation performances before and after the optimization. The results of simulation show that the optimized suspension system has better performance than before the optimization.

• 한국정보과학회논문지:정보통신
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• 제32권1호
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• pp.29-33
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• 2005

어디서나 접속이 가능한 무선네트워크는 더 이상 미래의 이야기가 아니다. 이미 우리 주변에는 이동 중에 네트워크에 접속할 수 있는 많은 장치들이 있다. 인터넷 프로토콜은 단말의 이동성뿐만 아니라 네트워크의 이동성까지도 지원하도록 확장되고 있다. 그러나 이동 단말과 이동 네트워크들이 중첩되면서 패킷의 전송 경로가 매우 복잡해지는 문제점이 있다. 중첩된 이동 네트워크 환경에서 이동 라우터는 네트워크를 빠져 나가는 패킷에 대해, 대응 단말은 이동 네트워크로 보내는 패킷에 대해 순차적으로 터널링을 하여 직접적인 경로를 형성할 수 있다. 본 논문에서는 순차적인 터널링을 수행하게 함으로써 중첩된 이동 네트워크에서 최적의 경로로 패킷을 전송할 수 있도록 하는 방법을 제시한다. 제시된 방법은 수식과 시뮬레이션을 통하여 성능을 평가하였다.

• 대한조선학회논문집
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• 제43권5호
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• pp.550-559
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• 2006

A design procedure for a ship with minimum total resistance was developed using a numerical optimization method called SQP(Sequential Quadratic Programming) and a CFD technique based on the Rankine source panel method with the nonlinear free surface boundary conditions. During the whole optimization process the geometry of the hull shape was represented based on the NURBS(Non-uniform rational B-spline) technique and the modification of the hull shape was controlled using the Bell-shaped distribution function to keep the fairness of the hull shape before and after the hull modification. The numerical analysis was carried out using 4000TEU container ship in the towing tank facility installed in the Pusan national university to know the validity of the developed algorithm for this study. As the results of the numerical analysis it proved that the resistance of the optimized hull is conspicuously reduced in comparison with the original hull in a wave-making resistance point of view.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.104-109
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• 1996

Continuum element sensitivity analysis (CONTESA) and system optimization (SYSOPT) for Noise, Vibration, and Harshness (NVH) have been developed and applied to automobile structures for sizing, topology, and configuration design using Mindlin plate and Timoshenko beam theories. The topology optimization has been developed using the density approach, sequential linear programming, and the adjoint variable method. CONTESA has been tested using various vehicle models. Optimized vehicles using CONTESA and SYSOPT are manufactured to validate the simulation-based design methodology.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.894-902
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• 2003

Prebiotics (peptides, N-acetyglucoamine, fructo-oligosaccharides, isomalto-oligosaccharides and galactooligosaccharides) were added to skim milk in order to improve the growth rate of contained Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium longum and Bifidobacterium bifidum. The purpose of this research was to study the potential synergy between probiotics and prebiotics when present in milk, and to apply modern optimization techniques to obtain optimal design and performance for the growth rate of the probiotics using a response surface-modeling technique. To carry out response surface modeling, the regression method was performed on experimental results to build mathematical models. The models were then formulated as an objective function in an optimization problem that was consequently optimized using a genetic algorithm and sequential quadratic programming approach to obtain the maximum growth rate of the probiotics. The results showed that the quadratic models appeared to have the most accurate response surface fit. Both SQP and GA were able to identify the optimal combination of prebiotics to stimulate the growth of probiotics in milk. Comparing both methods, SQP appeared to be more efficient than GA at such a task.

• 한국지능시스템학회논문지
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• 제11권9호
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• pp.827-832
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• 2001

본 논문은 수치적인 데이터를 이용하여 시스템을 구성하는 퍼지 모델링에서 각각의 장점들을 유지하면서 순차적으로 성능을 개선하는 방법을 제안한다. 기존의 다양한 퍼지 모델링의 최적화 방법들은 각각의 뛰어난 최적화 기법을 이용하면서도 순차적으로 퍼지 모델의 성능을 개선하려하는 시도는 많지 않았다. 이에 본 논문에서는 각 단계별로 최적의 성능을 구현하고 이를 다음 단계에서 초기로 이용함으로써 퍼지 모델의 성능이 순차적으로 개선되는 것을 제안하였다. 이는 각각의 최적화 기법들을 지속적으로 이용함으로써 원하는 모델의 성능을 개선하고자 하는 것이다. 제안된 방법의 유용성을 Rice taste 데이터 모델에 적용하여 제안된 방법이 이전의 연구보다 좋은 결과를 보임을 알았다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 춘계학술대회 논문집
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• pp.37-42
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• 2003

Fundamental Study for optimizing ship hull form using SQP(sequential quadratic programming) method in a resistance point of view is presented. The Wigley hull is used as an initial hull and numerical calculations are carried out according to various froude numbers. To obtain the ship resistance the wave resistance is evaluated by a Rankine source panel method with nonlinear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of a hull surface is represented and modified by B-spline surface patch. The displacement and the waterplane transverse 2nd moment of inertia of the hull is fixed during the optimization process. And the shp design program called EzHULL is used to draw the lines of the optimized hull form to perform the model test.

• 소음진동
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• 제7권6호
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• pp.967-974
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• 1997

Distributed piezoeletric sensor and actuator have been designed for efficient vibration control of a cantilevered beam. Both PZT and PVDF have been used in this study, the former as an actuator and the latter as a sensor for the integrated structure. We have optimized the position and the size of the PZT actuator and the electrode shape of the PVDF sensor. Finite element method is used to model the structure and the optimized actuators, we have designed the active electrode width of the PVDF sensor along the span of the beam. Actuator design is based on the criterion of minimizing the system energy in the control modes under a given initial condition. Model control forces for the residual (uncontrolled) modes have been minimized during the sensor design to minimize the observation spill-over. Genetic algorithm and sequential quadratic programming technique have been utilized as an optimization scheme. Discrete LQG control law has been applied to the integrated structure for real time vibration control. Performance of the sensor, the actuator, and the integrated smart structure has been demonstrated by experiments.