• Journal of Advanced Marine Engineering and Technology
• /
• 제31권1호
• /
• pp.58-66
• /
• 2007

Genetic Algorithms (GA) have some difficulties in practical applications because of too many function evaluations. To overcome these limitations, an approximated modeling method such as Response Surface Modeling(RSM) is coupled to GAs. Original RSM method predicts linear or convex problems well but it is not good for highly nonlinear problems cause of the average effect of the least square method(LSM). So the locally approximated methods. so called as moving least squares method(MLSM) have been used to reduce the error of LSM. In this study, the efficient evolutionary GAs tightly coupled with RSM with MLSM are constructed and then a 2-dimensional inviscid airfoil shape optimization is performed to show its efficiency.

• 한국품질경영학회:학술대회논문집
• /
• 한국품질경영학회 2010년도 춘계학술대회
• /
• pp.33-48
• /
• 2010

The purpose of this study is to empirically analyze the productivity change of the 10 Single PPM Certification Company in the 3 Industry(Electronics, Motor-Parts, Machines). In this study, Productivity change over the time in Korean small and medium sized firms in the 3 industries by the bootstrapped Malmquist Productivity Index(MPI). The traditional Malmquist Productivity Index(MPI) and Data Envelopment they could lead to wrong evaluations of the efficiency and productivity scores. In this paper, DEA and a MPI are combined with a bootstrap method in order to provide statistical inferences that analyze the performance of the Single PPM Certification Company. The data cover the period between 2004 and 2007. The result of this paper reveals : 1) The electronic industries(Motor-Parts, Machines). 2) average productivity Progress of the 7DMU(Electronics), 1DMU(Motor-Parts) and none(Machines).

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
• /
• pp.299-304
• /
• 2012

In terms of plane structure, tower-type apartments have several disadvantages compared to flat-type apartments in the aspect of ventilation rate. Such disadvantages may not produce good indoor cooling effects with natural ventilation inside the heated apartments in hot summer days, so they may cause high energy consumption by an increase in cooling load. The purpose of this study is to investigate ways for improving the indoor thermal environment of tower-type apartments in summer by conducting quantitative evaluations of the airflow distribution in households.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.656-661
• /
• 2009

In this study, theoretical analysis and evaluation tests were performed to assess the pipe stability against compaction equipments and vehicle loads when conventional construction criteria for pre-insulation heating pipes are applied and the alternative material, crushed sand, are used for backfills. The research outcomes shows that (1) the conventional code criteria for pre-insulated heating pipes is well established to support compaction equipments and vehicle loads, (2) the crushed sands as an alternative is usable as backfill materials for pre-insulated heating pipes based on the suitability evaluations of various types of pipes, and (3) the crushed sand agree well with the design consideration of pre-insulated heating pipes construction in the points of economical efficiency and construction criteria.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1998년도 추계학술대회
• /
• pp.82-83
• /
• 1998

In this study, variation of ground reaction force and energy consumption are investigated while walking with four different AK prostheses in order to obtain basic biomechanical data for developing AK prosthesis for Korean. It is a important information to investigate ground reaction force(GRF) and energy consumption to evaluate efficiency and stability of the prostheses.

• International Journal of Aeronautical and Space Sciences
• /
• 제14권4호
• /
• pp.341-349
• /
• 2013

This paper considers the optimum design of flexbeam cross-sections for a full-scale bearingless helicopter rotor, using an efficient hybrid optimization algorithm based on particle swarm optimization, and an improved genetic algorithm, with an effective constraint handling scheme for constrained nonlinear optimization. The basic operators of the genetic algorithm, of crossover and mutation, are revisited, and a new rank-based multi-parent crossover operator is utilized. The rank-based crossover operator simultaneously enhances both the local, and the global exploration. The benchmark results demonstrate remarkable improvements, in terms of efficiency and robustness, as compared to other state-of-the-art algorithms. The developed algorithm is adopted for two baseline flexbeam section designs, and optimum cross-section configurations are obtained with less function evaluations, and less computation time.

• Journal of the Korean Data and Information Science Society
• /
• 제12권2호
• /
• pp.113-124
• /
• 2001

의사결정나무모형 가운데 하나인 CHAID, 로지스틱 회귀모형, 이들을 이용한 각각의 베깅모형 등 4가지 예측분류모형에 대한 오분류율과 훈련시간을 표본크기별로 계산하고, 이들 모형에 대한 모의실험 비교를 통하여 주어진 알고리즘들의 효율성을 평가하였다. 베깅 의사결정나무모형은 오분류율은 낮았으나 상대적으로 훈련시간이 가장 길었다.

• 한국철도학회논문집
• /
• 제12권5호
• /
• pp.751-760
• /
• 2009

본 연구는 화물수송을 둘러싼 사회적 경제적 환경변화 속에서 철도물류의 활성화가 시대적 과제가 되고 있는 시점에서 철도로의 모달시프트가 기대되는 철도컨테이너수송에 주목하여 화주, 복합운송업체, 운영자를 대상으로 설문조사를 실시, 철도의 이용현황, 이용확대를 위한 개선사항, 환경문제에 대한 대응상황을 분석함으로써 철도물류서비스의 생산성 향상을 위한 개선방안, 나아가 국가정책과의 공동보조를 통한 철도화물수송으로의 모달시프트 가능성에 대하여 검토하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -2
• /
• pp.645-648
• /
• 2000

A workflow is a flow of work carried out by multiple people. In order to increase efficiency, it is re-quired to change the current workflow dynamically. Till now, three types of dynamic changes: flush, abort, and synthetic cut-over (SCO) , have been proposed. How- ever, the performance evaluations for dynamic workflow changes have not been undertaken. To do so, measuring the amount of time cost making a single change (called change time) and comparing the methods for obtaining such times become ever important. In this paper, we first define change time and then propose a computation method individually for each change type. Finally, we evaluate the performance of an example net change by computing the change times.

• 대한수학회지
• /
• 제59권6호
• /
• pp.1067-1082
• /
• 2022

This paper presents a new optimal three-step eighth-order family of iterative methods for finding multiple roots of nonlinear equations. Different from the all existing optimal methods of the eighth-order, the new iterative scheme is constructed using one function and three derivative evaluations per iteration, preserving the efficiency and optimality in the sense of Kung-Traub's conjecture. Theoretical results are verified through several standard numerical test examples. The basins of attraction for several polynomials are also given to illustrate the dynamical behaviour and the obtained results show better stability compared to the recently developed optimal methods.