• 한국안전학회지
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• 제36권4호
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• pp.1-11
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• 2021

Piping systems comprising pumps and valves are essential in the power plant, oil, and defense industry. Their purpose includes a stable supply of the working fluid or ensuring the target system's safe operation. However, piping system accidents due to leakage of toxic substances, explosions, and natural disasters are prevalent In addition, with the limited maintenance personnel, it becomes difficult to detect, isolate, and reconfigure the damage of the piping system and recover the unaffected area. An autonomous recovery piping system can play a vital role under such circumstances. The autonomous recovery algorithms for the piping system can be divided into low-pressure control algorithms, hydraulic resistance control algorithms, and flow inventory control algorithms. All three methods include autonomous opening/closing logic to isolate damaged areas and recovery the unaffected area of piping systems. However, because each algorithm has its strength and weakness, appropriate application considering the overall design, vital components, and operating conditions is crucial. In this regard, preliminary research on algorithm's working principle, its design procedures, and expected damage scenarios should be accomplished. This study examines the characteristics of algorithms, the design procedure, and working logic. Advantages and disadvantages are also analyzed through simulation results for a simplified piping system.

• 한국강구조학회 논문집
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• 제24권6호
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• pp.701-710
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• 2012

최근에는 고층구조물이나 해양구조물(플랜트)의 경우 대부분 대형화로 설계 및 시공되고 있다. 대형구조물의 경우 주로 강재(steel)를 사용하여 설계하고 있다. 구조물 설계는 설계단계에서 최상의 부재를 선택하는 최적화를 적용함으로서 비용을 줄이는 경제적인 효과를 얻을 수 있다. 본 연구에서는 트러스와 프래임 구조물의 최적설계에 연속변수와 이산변수를 사용하여 최적화 하였고, 설계에서 사용된 이산자료는 규격화된 강재에 대한 자료와 데이터화된 이산자료를 사용하였다. 최적화는 이 모두에 적합한 이산최적화를 적용하였다. 최적화 기법으로는 유전자 알고리즘을 사용하였으며, 사용된 구조물은 10-Bar, 25-Bar 트러스와 1경간 2층, 1경간 7층 프레임 구조물이다. 설계시 제약조건은 고유진동수와 부재응력, 변위제약조건들이 적용되었다. 유전자 알고리즘에는 번식과장에서 엘리트 개체가 2번 사용되도록 하였으며, 제약조건 위반시 패널티를 사용하는 방법을 사용하였다.

• 한국수자원학회논문집
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• 제34권5호
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• pp.567-575
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• 2001

관망해석 시뮬레이션과 유전자 알고리즘에 기초한 최적화 모형을 이용하여 최소비용의 배수관망을 설계하는 방법론이 개발되었다. 유전자 알고리즘은 추계학적 최적화 기법의 하나로, 비선형적이고 계산량이 많은 관망설계 문제에 적용하기에 적합한 장점을 가지고 있다. 기존의 연구가 대부분 전체 관망의 신설 혹은 기존 관망의 병렬확장에만 적용하던 것에 비해 본 연구에서는 개발된 모형을 수지상(tree-type) 신설관 및 loop형 병렬증설관이 공존하는 시스템에 적용하였다. 개발된 모형을 백련 배수관로를 대상으로 적용한 결과, 수리학적 제약조건을 만족시키면서 사업비를 최대 5.37% 절감할 수 있는 설계를 제공하는 것으로 나타났다.

• 한국CDE학회논문집
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• 제3권1호
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• pp.68-85
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• 1998

Solid modeling refers to techniques for unambiguous representations of three-dimensional objects. Feature recognition is a sub-discipline focusing on the design and implementation of algorithms for detecting manufacturing information such as holes, slots, etc. in a solid model. Automated feature recognition has been an active research area in stolid modeling for many years, and is considered to be a critical component for CAD/CAM integration. This paper gives a technical overview of the state of the art in feature recognition research. Rather than giving an exhaustive survey, I focus on the three currently dominant feature recognition technologies: graph-based algorithms, volumetric decomposition techniques, and hint-based geometric reasoning. For each approach, I present a detailed description of the algorithms being employed along with some assessments of the technology. I conclude by outlining important open research and development issues.

• Ocean Systems Engineering
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• 제11권4호
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• pp.301-312
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• 2021

An optimization framework has been established and applied to a shipshape parametric FPSO hull design. A single point moored (SPM) shipshape floating system suffers a significant level of the roll motion in both the wave frequencies and low wave frequencies, which presents a coupling effect with the horizontal weathervane motion. To guarantee the security of the operating instruments installed onboard, a parametric hull design of an FPSO has been optimized with improved hydrodynamics performance. With the optimized parameters of the various hull stations' longitudinal locations, the optimization through Genetic Algorithms (GAs) has been proven to provide a significantly reduced level of the 1st-order and 2nd-order roll motion. This work presents a meaningful framework as a reference in the process of an SPM shipshape floating system's design.

• 한국BIM학회 논문집
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• 제9권4호
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• pp.41-50
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• 2019

Digital models for a cable-stayed bridge are defined considering data-driven engineering from design to construction. Algorithms for digital object generation of each component of the cable-stayed bridge were developed. Using these algorithms, Level-3 BIM practices can be realized from design stages. Based on previous practices, digital object library can be accumulated. Basic digital models are modified according to given design conditions by a designer. Once design models are planned, various applications using the models are linked the models such as estimation, drawings and mechanical properties. Federated bridge models are delivered to construction stages. In construction stage, the models can be efficiently revised according to the changed situations during construction phases. In this paper, measured coordinates are imported to the model generation algorithms and revised models are obtained. Augmented reality devices and their applications are proposed. AR simulations in construction site and in office condition are tested. From this pilot test of digital models, it can be said that Level-3 BIM practices can be realized by using in-house modeling algorithms according to different purposes.

• 한국경영과학회지
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• 제23권3호
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• pp.1-15
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• 1998

Genetic algorithms(GAs) are suited for solving structural design problems, since they handle the design variables efficiently. This ability of GAs considers then as a good choice for optimization problems. Nevertheless, there are many situations that the conventional genetic algorithms do not perform particularly well, and so various methods of hybridization have been proposed. Thus. this paper develops a hybrid genetic algorithm(HGA) to incorporate a local convergence method and precision search method around optimum in the genetic algorithms. In case study. it is showed that HGA is able consistently to provide efficient, fine quality solutions and provide a significant capability for solving structural design problems.

• 정보교육학회논문지
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• 제19권4호
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• pp.409-418
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• 2015

본 연구의 목적은 백워드 설계 모형을 적용하여 초등학교 소프트웨어 교육 운영 지침의 '알고리즘과 프로그래밍' 단원의 교수학습계획을 개발함으로써, 백워드 설계 모형이 소프트웨어 교육과정 구성에 주는 시사점을 도출하는 것이다. 연구자는 Wiggins와 McTighe의 백워드 설계 탬플릿에 기초하여, '알고리즘과 프로그래밍' 단원의 교수설계를 개발하였다. 첫째, 교육부에서 제시한 소프트웨어 교육과정 운영 지침에 제시되어 있는 목표, 내용체계표, 성취기준, 단원목표 등을 확인함으로써, '알고리즘과 프로그래밍' 단원에 대한 영속적 이해, 포괄적이고 본질적인 질문, 핵심 지식과 핵심 기능을 도출하였다. 둘째, GRASPS 기법을 활용하여 '알고리즘과 프로그래밍' 단원의 수행 과제와 총체적인 루브릭을 개발하였다. 셋째, '알고리즘과 프로그래밍' 단원을 효과적으로 수업하기 위하여, WHERETO 요소의 14개 활동으로 구성된 7차시 수업을 개발하였다. 마지막으로, 백워드 설계 모형을 이용한 교육과정 구성이 소프트웨어 교육에 미치는 효용성에 대하여 고찰하였다. 백워드 설계 모형은 소프트웨어 교육을 위한 단원 및 수업 설계 개선에 많은 시사점을 제공할 것이라 기대한다.

• Industrial Engineering and Management Systems
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• 제8권1호
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• pp.22-28
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• 2009

We consider facility layout problems, where mn facility units are assigned into mn cells. These cells are arranged into a rectangular pattern with m rows and n columns. In order to solve this cell type facility layout problem, many approximation algorithms with improved local search methods were studied because it was quite difficult to find exact optimum of such problem in case of large size problem. In this paper, new algorithms based on Simulated Annealing (SA) method with two neighborhood generation methods are proposed. The new neighborhood generation method adopts the exchanging operation of facility units in accordance with adjacent preference. For evaluating the performance of the neighborhood generation method, three algorithms, previous SA algorithm with random 2-opt neighborhood generation method, the SA-based algorithm with the new neighborhood generation method (SA1) and the SA-based algorithm with probabilistic selection of random 2-opt and the new neighborhood generation method (SA2), are developed and compared by experiment of solving same example problem. In case of numeric examples with problem type 1 (the optimum layout is given), SA1 algorithm could find excellent layout than other algorithms. However, in case of problem type 2 (random-prepared and optimum-unknown problem), SA2 was excellent more than other algorithms.

• 전기학회논문지
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• 제59권1호
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• pp.184-191
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• 2010

Many researchers have been considering genetic algorithms to system optimization problems. Especially, real-coded genetic algorithms are very effective techniques because they are simpler in coding procedures than binary-coded genetic algorithms and can reduce extra works that increase the length of chromosome for wide search space. Thus, this paper presents a fuzzy system design technique to improve the performance of the fuzzy system. The proposed system consists of two procedures. The primary tuning procedure coarsely tunes fuzzy sets of the system using the k-means clustering algorithm of which the structure is very simple, and then the secondary tuning procedure finely tunes the fuzzy sets using enhanced real-coded genetic algorithms based on the primary procedure. In addition, this paper constructs multiple fuzzy systems using a data preprocessing procedure which is contrived for reflecting various characteristics of nonlinear data. Finally, the proposed fuzzy system is applied to the field of time series prediction and the effectiveness of the proposed techniques are verified by simulations of typical time series examples.