• 설비공학논문집
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• 제18권8호
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• pp.635-640
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• 2006

An optimizer has been applied for the optimal design of pipe diameters in the pipe flow network problems. Pipe network flow analysis, which is developed separately, is performed within the interface for the optimization algorithm. A pipe network is chosen for the test, and optimizer GenOpt is applied with Holder-Mead-O'Niell's simplex algorithm after solving the network flow problem by the Newton-Raphson method. As a result, optimally do-signed pipe diameters are successfully obtained which minimize the total design cost. Design cost of pipe flow network can be considered as the sum of pipe installation cost and pump operation cost. In this study, a practical and efficient solution method for the pipe network optimization is presented. Test system is solved for the demonstration of the present optimization technique.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.905-908
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• 2009

In the management of groundwater in coastal areas, saltwater intrusion associated with extensive groundwater pumping, is an important problem. The groundwater optimization model is an advanced method to study the aquifer and decide the optimal pumping rates or optimal well locations. Cheng and Park gave the analytical solutions to the optimization problems basing on Strack's analytical solution. However, the analytical solutions have some limitations of the property of aquifer, boundary conditions, and so on. A simulation-optimization numerical method presented in this study can deal with non-homogenous aquifers and various complex boundary conditions. This simulation-optimization model includes the sharp interface solution which solves the same governing equation with Strack's analytical solution, therefore, the freshwater head and saltwater thickness should be in the same conditions, that can lead to the comparable results in optimal pumping rates and optimal well locations for both of the solutions. It is noticed that the analytical solutions can only be applied on the infinite domain aquifer, while it is impossible to get a numerical model with infinite domain. To compare the numerical model with the analytical solutions, calculation of the equivalent boundary flux was planted into the numerical model so that the numerical model can have the same conditions in steady state with analytical solutions.

• 한국CDE학회논문집
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• 제10권2호
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• pp.143-150
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• 2005

A design framework to employ the multidisciplinary design optimization technologies on a computer system has been developed and is named as the Extensible Multidisciplinary Design Integration and Optimization System (EMDIOS). The framework can not only effectively solve complex system design problems but also conveniently handle MDO problems. Since the EMDIOS exploits both state-of-the-art of computing capabilities and sophisticated optimization techniques, it can overcome many scalability and complexity problems. It can make users who are not even familiar with the optimization technology use EMDIOS easily to solve their design problems. The client of EMDIOS provides a front end for engineers to communicate the EMDIOS engine and the server controls and manages various resources luck as scheduler, analysis codes, and user interfaces. EMDIOS client supports data monitoring, design problem definition, request for analyses and other user tasks. Three main components of the EMDIOS are the Engineering Design Object Model which is a basic idea to construct EMDIOS, EMDIOS Language (EMDIO-L) which is a script language representing design problems, and visual modeling tools which can help engineers define design problems using graphical user interface. Several example problems are solved and EMDIOS has shown various capabilities such as ease of use, process integration, and optimization monitoring.

• 대한조선학회논문집
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• 제34권1호
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• pp.93-101
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• 1997

본 연구에서는 전통적인 비선형 최적화 기법의 문제점을 극복하기 위하여 유전자알고리즘과 지식베이스의 통합을 통한 새로운 개념의 최적화 기법을 개발하였다. 여기에서는 제한조건이 있는 비선형 최적화 문제를 해결하기 위해 사용되는 전통적인 순차적 선형화 방법과 새로운 유전자 알고리즘의 장단점을 서로 보완한 하이브리드형 최적화 기법을 개발하였다. 여기에 지식베이스를 통한 최적화 지원 기법 및 최적화 모델의 자동생성 모듈을 개발하여 최적화 모텔의 성능을 한층 개선할 수 있었다. 개발된 최적화 기법의 검증을 위하여 수학적 비선형 모델을 이용한 여러가지 기법의 비교 검토를 수행하였다.

• Steel and Composite Structures
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• 제47권6호
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• pp.759-779
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• 2023

The paper proposes two hybrid metaheuristic optimization and artificial neural network (ANN) methods for the close prediction of the ultimate axial compressive capacity of concentrically loaded concrete filled double skin steel tube (CFDST) columns. Two metaheuristic optimization, namely genetic algorithm (GA) and particle swarm optimization (PSO), approaches enable the dynamic training architecture underlying an ANN model by optimizing the number and sizes of hidden layers as well as the weights and biases of the neurons, simultaneously. The former is termed as GA-ANN, and the latter as PSO-ANN. These techniques utilize the gradient-based optimization with Bayesian regularization that enhances the optimization process. The proposed GA-ANN and PSO-ANN methods construct the predictive ANNs from 125 available experimental datasets and present the superior performance over standard ANNs. Both the hybrid GA-ANN and PSO-ANN methods are encoded within a user-friendly graphical interface that can reliably map out the accurate ultimate axial compressive capacity of CFDST columns with various geometry and material parameters.

• Structural Engineering and Mechanics
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• 제88권3호
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• pp.273-285
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• 2023

This study examines how the interaction between soil and a wind turbine's supporting system affects the optimal design. The supporting system resting on an elastic soil foundation consists of a steel conical tower and a concrete circular raft foundation, and it is subjected to wind loads. The material cost of the supporting system is aimed to be minimized employing various metaheuristic optimization algorithms including teaching-learning based optimization (TLBO). To include the influence of the soil in the optimization process, modified Vlasov and Gazetas elastic soil models are integrated into the optimization algorithms using the application programing interface (API) feature of the structural analysis program providing two-way data flow. As far as the optimal designs are considered, the best minimum cost design is achieved for the TLBO algorithm, and the modified Vlasov model makes the design economical compared with the simple Gazetas and infinitely rigid soil models. Especially, the optimum design dimensions of the raft foundation extremely reduce when the Vlasov realistic soil reactions are included in the optimum analysis. Additionally, as the designated design wind speed is decreased, the beneficial impact of soil interaction on the optimum material cost diminishes.

• 대한안전경영과학회지
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• 제12권2호
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• pp.153-159
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• 2010

The air logistics process is complex and needs many informations because various agencies participate in the logistics service and many stakeholders in air logistics. But it is hard to improve the infra of facilities because of an enormous expense, so air logistics process has to simplify for growing air freight. Nevertheless some documents are same, they should be changed due to different format. Also documents have to change even though different documents have same informations. Consequently, errors are increased because the names of the same data are different from each other and stakeholders have to reproduce the documents. In order to mitigate these problems, we selected documents and analyzed document data for the interface optimization in general air logistics process. Next, we unified the data names and defined contents of data. Also we set the type of the defined data on DB type, and gave the code to the defined data. It made easy to exchange informations among the stakeholders to match documents corresponding with the defined data. Finally, the simulation of air logistics processes was performed the quantitative analysis of the data that occur in the air logistics. In conclusion, we expect to reduce the inefficiency such as reproduction of data and the errors by improving the interface of information.

• 한국정보통신학회논문지
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• 제25권12호
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• pp.1914-1919
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• 2021

첨단산업의 발전에 따라 영상처리 하드웨어의 연구는 필수적이고, 실제 칩 동작을 위해서는 게이트 수준의 타이밍 검증이 필요하다. 이를 위해 주로 FPGA 기반 검증이 이루어지는데 기존에는 DDR3 메모리 인터페이스를 적용했지만, 최근에는 FPGA 스펙이 향상되면서 DDR4 메모리가 사용된다. 이 때 기존에 사용하던 메모리 인터페이스를 적용하면 CPU와 메모리의 성능 차이에 의한 신호들의 타이밍 불일치가 발생하기 때문에 사용할 수 없다. 본 논문에서는 기존 인터페이스 시스템 FSM의 State 최적화를 통해 문제를 해결하고, 이 과정에서 AXI Data Width 수정을 통해 데이터 읽기 속도를 2배 증가시킨다. 실제 사례 분석을 위해 Xilinx 사의 SoC보드 중 DDR3 메모리를 사용하는 ZC706과 DDR4 메모리를 사용하는 ZCU106을 사용한다.

• 한국멀티미디어학회논문지
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• 제16권12호
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• pp.1482-1494
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• 2013

이 연구개발의 결과 인터페이스 사용자 플랫폼은 최근 고도화된 인터페이스 기술의 특성을 반영하고 소셜 미디어에 의해 발생되는 정보를 활용하여 미래 도시에서 최적의 인터페이스 환경을 지원한다. 이는 미래 지능형 도시의 스마트 공간을 공간 사용자가 보다 쉽고 효율적인 인터페이스 환경에서 정보에 접근할 수 있도록 인터페이스 사용자 플랫폼 구성을 목적으로 하며, 플랫폼 구성을 위한 주요 모듈을 구성한다. 인터페이스 사용자 플랫폼 모듈은 시각화 서비스를 기본으로 하며, 시각화 에이전트, 시각화 소셜 네트워크, 시각 데이터, 시각 클래스, 시각화 아이콘, 시각지도, 시각화 서비스 등의 모듈로 구성된다. 본 연구에서는 전달하고자하는 정보를 포함하는 서비스 종류에 따라 적절한 인터페이스 기술을 적용할 수 있는 인터페이스 환경을 찾고자 본 연구의 최종 결과물인 "인터페이스 사용자 플랫폼"을 제시하였다.

• 한국결정성장학회지
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• 제14권4호
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• pp.155-159
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• 2004

열교환법을 활용한 사파이어 단결정 성장 공정에서 도가니 형상 변화가 결정 온도와 고/액 계면 형태에 미치는 영향에 관해 고찰하기 위해 유한요소법, implicit Euler법, frontal 해석 연산을 활용한 수치해석을 수행하였다. 개발된 컴퓨터 시뮬레이션 기법은 고/액 계면의 형상이 반구 형상에서 평면 형상으로 전환되는 열전달 현상 해석에 효율적이다. 본 연구에서는 고/액 계면의 휨도를 개선하기 위해, 도가니 밑면의 다양한 형상을 고려하였으며, 도가니 형상은 공정 최적화 변수로 고려되어야 한다.