• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.250-278
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• 2004

The product rate variation problem, to be called the PRVP, is to sequence different type units that minimizes the maximum value of a deviation function between ideal and actual rates. The PRVP is an important scheduling problem that arises on mixed-model assembly lines. A surge of research has examined very interesting methods for the PRVP. We believe, however, that several issues are still open with respect to this problem. In this study, we consider convex bipartite graphs, perfect matchings, permanents and balanced sequences. The ultimate objective of this study is to show that we can provide a more efficient and in-depth procedure with a graph theoretic approach in order to solve the PRVP. To achieve this goal, we propose formal alternative proofs for some of the results stated in the previous studies, and establish several new results.

• Advances in Automotive Engineering
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• 제1권1호
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• pp.41-59
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• 2018

In the study, investigation of fiber- reinforced composite materials that can be an alternative to conventional steel was performed by finite element analysis with the help of software. Steel and composite materials have been studied on a four axle truck chassis model. Three-dimensional finite element model was created with software, and then analyzes were performed. The analyses were performed for static and dynamic/fatigue cases. Fatigue cases are formed with the help of design spectra model and fatigue analyses were performed as static analyses with this design spectra. First, analyses were performed for steel and after that optimization analyses were made for the AS4-PEEK carbon fiber composite and Eglass-Epoxy fiber composite materials. Optimization of composite material analyzes include determining the total laminate thickness, thickness of each ply, orientation of each ply and ply stacking sequence. Analyzes were made according to macro mechanical properties of composite, micromechanics case has not been considered. Improvements in weight reduction up to %50 provided at the end of the composite optimization analyzes with satisfying stiffness performance of chassis. Fatigue strength of the composite structure depends on various factors such as, fiber orientation, ply thickness, ply stack sequence, fiber ductility, ductility of the matrix, loading angle. Therefore, the accuracy of theoretical calculations and analyzes should be correlated by testing.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.608-615
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• 2022

Construction projects are large-scale projects that require extensive construction costs and resources. Especially, scheduling is considered as one of the essential issues for project success. However, the schedule and resource management are challenging to conduct in high-tech construction projects including complex design of MEP and architectural finishing which has to be constructed within a limited workspace and duration. In order to deal with such a problem, this study suggests resource and sequence optimization using constraint programming in construction projects. The optimization model consists of two modules. The first module is the data structure of the schedule model, which consists of parameters for optimization such as labor, task, workspace, and the work interference rate. The second module is the optimization module, which is for optimizing resources and sequences based on Constraint Programming (CP) methodology. For model validation, actual data of plumbing works were collected from a construction project using a five-minute rate (FMR) method. By comparing actual data and optimized results, this study shows the possibility of reducing the duration of plumbing works in construction projects. This study shows decreased overall project duration by eliminating work interference by optimizing resources and sequences within limited workspaces.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.183-199
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• 2007

In this paper we research the problem in which the objective is to minimize the sum of squared deviations of job expected completion times from the due date, and the job processing times are stochastic. In the problem the machine is subject to stochastic breakdowns and all jobs are preempt-repeat. In order to show that the replacing ESSD by SSDE is reasonable, we discuss difference between ESSD function and SSDE function. We first give an express of the expected completion times for both cases without resampling and with resampling. Then we show that the optimal sequence of the problem V-shaped with respect to expected occupying time. A dynamic programming algorithm based on the V-shape property of the optimal sequence is suggested. The time complexity of the algorithm is pseudopolynomial.

• 한국측량학회지
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• 제27권1호
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• pp.723-733
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• 2009

This study proposes a sequence of procedures to extract building boundaries and planar patches through segmentation of rasterized lidar data. Although previous approaches to building extraction have been shown satisfactory, there still exist needs to increase the degree of automation. The methodologies proposed in this study are as follows: Firstly, lidar data are rasterized into grid form in order to exploit its rapid access to neighboring elevations and image operations. Secondly, propagation of errors in raw data is taken into account for in assessing the quality of gradients-driven properties and further in choosing suitable parameters. Thirdly, extraction of planar patches is conducted through a sequence of processes: histogram analysis, least squares fitting, and region merging. Experimental results show that the geometric components of building models could be extracted by the proposed approach in a streamlined way.

• ETRI Journal
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• 제29권4호
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• pp.527-529
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• 2007

In this paper, a decision-tree-based Markov model for phrase break prediction is proposed. The model takes advantage of the non-homogeneous-features-based classification ability of decision tree and temporal break sequence modeling based on the Markov process. For this experiment, a text corpus tagged with parts-of-speech and three break strength levels is prepared and evaluated. The complex feature set, textual conditions, and prior knowledge are utilized; and chunking rules are applied to the search results. The proposed model shows an error reduction rate of about 11.6% compared to the conventional classification model.

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.203-208
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• 2002

In case of the problems with multiple plants, alternative operation sequence, alternative machine, setup time, and transportation time between plants, we need a robust methodology for the integration of process planning and scheduling in supply chain. The objective of this model is to minimize the tardiness and to maximize the resource utilization. So, we propose a multi-objective model with limited-capacity constraint. To solve this model, we develope an efficient and flexible model using adaptive genetic algorithm(AGA), compared to traditional genetic algorithm(TGA)

• 한국전자거래학회지
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• 제9권1호
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• pp.1-19
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• 2004

시간적 금전적 압박으로 최근의 웹 응용에서는 체계적인 시험작업이 종종 간과되곤 한다. 게다가 효과적인 웹 응용 시험 방법이 많지 않아 웹 응용에 기존의 시험 방법들을 적용하면서 개발자들은 많은 어려움을 겪고 있다. 빠르고 효과적 인 시험을 위하여 웹 페이지간의 메시지를 모델링한 UML 순차도(Sequence Diagram)로부터 웹 응용을 위한 시험사례를 추출하는 방법을 제안한다. 웹 응용을 위한 시험사례들은 UML의 순차도에서 자기 호출 메시지 (Self-Call Messages)를 포함한 메시지들로부터 추출된다. 시험사례는 시험할 대상인 메시지와 스크립트 함수, 서버 페이지와 추가적인 시험값들로 구성된다. 또한, 웹 응용 시험을 지원하기 위한 간단한 도구를 제시한다. 이 시험 도구는 웹 응용을 시험하기 위한 URL을 생성하고 이를 실행하여 그 결과를 보인다. 생성된 URL은 시험할 서버 페이지의 주소와 추가적인 시험값들로 구성된다. 이 도구는 마이크로소프트 비주얼 베이직으로 작성하였다. 회원 관리 기능을 수행하는 웹 응용개발 과제에 제안하는 시험사례 추출방법과 시험 지원 도구를 적용하였으며 그 유용성을 확인하였다.

• Korean Chemical Engineering Research
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• 제52권5호
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• pp.564-573
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• 2014

이 연구는 벤젠과 프로필렌의 기상반응을 통해 쿠멘을 생산하는 쿠멘 생산 공정의 경제성 최적화에 대한 것이다. 최적화의 목적함수는 제품 판매 이득에서 자본비용, 유틸리티 비용, 원료 비용을 뺀 연간 조업이득이고, 설계변수는 6개이다. 설계변수의 변화에 따른 조업이득의 계산을 위해 Unisim Design과 Matlab을 연동하였다. 최적화는 3단계로 수행되었다. 설계변수를 샘플링한 후 조업이득 데이터를 얻고, 이 데이터로부터 설계변수와 조업이득의 관계를 추정 모델로 표현하고, 이 모델을 이용하여 최적화하였다. 추정모델로는 반응표면법에서 사용되는 2차 회귀 다항식과 비선형 모델인 support vector regression을 비교하였다. 설계변수의 샘플링 방법으로는 중심합성계획과 Hammersley 순차 추출법을 비교하였다. 각각 얻어진 모델을 이용한 최적화 결과, 추정방법으로는 SVR이, 샘플링 방법은 Hammersley 순차추출법이 더 정확하였다. 최적화된 조업이득은 연간 17.96 MM$로, 기준 조건에서의 연간 16.04 MM$에 비해 12% 증가하였다.

• 한국컴퓨터정보학회논문지
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• 제15권5호
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• pp.33-38
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• 2010

본 논문에서는 USB 인터페이스 방식의 웹 카메라를 통해 입력받은 영상을 영상처리 기법을 통해 손의 움직임과 손가락 개수를 파악하여 실시간으로 마우스의 기능을 구현하는 알고리즘을 제안하였다. 웹 카메라로부터 입력받은 RGB 컬러모델 영상을 조명 변화에 강한 YCbCr 컬러 모델 영상으로 변환하여 휘도 성분을 제외한 색차 성분만으로 피부색을 추출해 이진화된 영상으로 만든다. YCbCr 컬러 모델을 이용하여 피부색을 추출할 경우, 주변 환경에 의해 정확한 손 영역을 추출할 수 없어 라벨링(labeling)과 열림(opening) 연산, 닫힘(closing) 연산을 수행하여 정확한 손 영역을 추출한다. 이렇게 추출된 손 영역의 중심을 이용하여 마우스 포인터를 이동시키며 손가락 개수를 이용하여 마우스의 클릭을 수행하였다. 구현된 제안 기법을 실험한 결과, 마우스 포인터 이동을 위한 기능 성공률은 평균 94.0%, 손가락 개수 인식률은 평균 96.0%로 실용화 가능성을 보였다.