• 대한산업공학회지
• /
• 제5권1호
• /
• pp.45-51
• /
• 1979

This paper presents a heuristic solution procedure for the quadratic assignment problem, ranking procedure, which can handle the case where not all of the facilities have the same size of area. The ranking procedure is found more efficient than two other existing heuristic procedures from results of computational experience. Based on the out-patients flow pattern and the procedure developed, an improved layout of the three existing general hospitals is developed with the objective of minimizing the total distance travelled by patients in the central and the out-patient clinic.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집A
• /
• pp.734-739
• /
• 2001

In this paper, an algorithm for stacking sequence optimization which deals with discrete ply angles is used for optimization of composite laminated plates. To handle discrete ply angles, the branch and bound method is modified. Numerical results show that the optimal stacking sequence is found with fewer evaluations of objective function than expected with the size of feasible region, which shows the algorithm can be effectively used for layup optimization of composite laminates..

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제2권1호
• /
• pp.88-93
• /
• 1998

It is frequently important to approximate a rational B$\acute{e}$zier curve by an integral, i.e., polynomial one. This need will arise when a rational B$\acute{e}$zier curve is produced in one CAD system and is to be imported into another system, which can only handle polynomial curves. The objective of this paper is to present an algorithm to approximate rational B$\acute{e}$zier curves with polynomial curves of higher degree.

• 대한조선학회지
• /
• 제25권1호
• /
• pp.11-20
• /
• 1988

From the engineering point of view, a synthesis as well as an analysis technique is explored to search for the improved design of grillage which is common in ship structure. As an approximate analysis method for the grillage, an interaction reaction method is developed and compared with the finite element method. It is found that the discrepancy between these two methods is so negligible that the percent method could be used effectively for the grillage analysis. As an optimization technique, a feasible direction method could be used is combined with the intersection reaction method in order to design a minimum weight optimal grillage. The feasible direction method shows a good numerical performance although it requires more calculation times compared with the direct search method. Finally, the application of multiple objective optimization method to grillage is investigated in order to resolve conflicts existed between the multiple objectives which is a common characteristic of structure design problem. Goal programming method is extended to handle a nonlinear property of constraints and objective functions. It seems that the nonlinear goal programming could help not only to establish a relative importance of each objective, but also enable the designer to choose the best combination of design variables.

• 대한임베디드공학회논문지
• /
• 제19권2호
• /
• pp.107-114
• /
• 2024

Mobile ad hoc networks represent self-configuring networks of mobile devices that communicate without relying on a fixed infrastructure. However, traditional routing protocols in such networks encounter challenges in selecting efficient and reliable routes due to dynamic nature of these networks caused by unpredictable mobility of nodes. This often results in a failure to meet the low-delay and low-energy consumption requirements crucial for such networks. In order to overcome such challenges, our paper introduces a novel multi-objective and adaptive routing scheme based on the Q-learning reinforcement learning algorithm. The proposed routing scheme dynamically adjusts itself based on measured network states, such as traffic congestion and mobility. The proposed approach utilizes Q-learning to select routes in a decentralized manner, considering factors like energy consumption, load balancing, and the selection of stable links. We present a formulation of the multi-objective optimization problem and discuss adaptive adjustments of the Q-learning parameters to handle the dynamic nature of the network. To speed up the learning process, our scheme incorporates informative shaped rewards, providing additional guidance to the learning agents for better solutions. Implemented on the widely-used AODV routing protocol, our proposed approaches demonstrate better performance in terms of energy efficiency and improved message delivery delay, even in highly dynamic network environments, when compared to the traditional AODV. These findings show the potential of leveraging reinforcement learning for efficient routing in ad hoc networks, making the way for future advancements in the field of mobile ad hoc networking.

• 품질경영학회지
• /
• 제26권3호
• /
• pp.60-70
• /
• 1998

When driving the expected loss generated by the quality deviation, Taguchi(1991b) assumed that an objective characteristic has the uniform distribution in its control limit. But it is reasonable to assume that an objective characteristic has the normal distribution than the uniform distribution. Since the triangular distribution is similar to the normal distribution and easy to handle as well, in this article, we first find the optimum measurement interval and the optimum control limit under the triangular distribution. Under the normal assumption, the modified method is compared to Taguchi's. Secondly we find the numerical value solution of the optimum measurement interval and the optimum control limit under the normal distribution.

• 산업경영시스템학회지
• /
• 제34권4호
• /
• pp.138-144
• /
• 2011

The design flexibility and robustness have become key factors to handle various sources of uncertainties at the early phase of design. Even though designers are uncertain about which single values to specify, they usually have a preference for certain values over others. In the first and second reports of a four-part paper, a set-based design approach has been proposed for achieving design flexibility and robustness while capturing designer's preference, and its effectiveness has been illustrated with a simple vehicle side-door impact beam design problem. This report presents the applicability of the proposed design approach to the large-scale multi-objective design optimization with a successful implementation of real vehicle side-door structure design.

• Industrial Engineering and Management Systems
• /
• 제12권2호
• /
• pp.95-102
• /
• 2013

It is difficult to determine an appropriate discount price for daily perishable products to increase profit from a long-term standpoint. Even if the discount pricing is efficient to increase profit of the day, consumers memorize the sales price and they might hesitate to purchase the product at a regular price the following day. The authors discussed the inventory clearance pricing for a single period in our previous study by constructing a mathematical model to derive an optimal sales price to maximize the expected profit by considering the reference price effect of demand. This paper extends the discussion to handle the discount pricing for multiple periods. A mathematical analysis is first conducted to reveal the properties on an objective function, which is the present value of total expected profits for multiple periods. An algorithm is then proposed to derive an optimal price for asymmetric consumers. Numerical experiments investigate the characteristics of the objective function and optimal pricings.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2002년도 학술발표회 논문집(II)
• /
• pp.829-836
• /
• 2002

The paper presents a multi-objective genetic algorithm approach to the design of a water distribution network. The objectives considered are minimization of network cost and maximization of a reliability measure. In this study, a new reliability measure, called network resilience, is introduced. This measure mimics a designer's desire of providing excess power at nodes and designing reliable loops with practicable pipe diameters. The proposed method produces a set of Pareto-optimal solutions in the search space of cost and network resilience. Genetic algorithms are observed to be poor in handling constraints. To handle constraints in a better way, a constraint handling technique that does not require a penalty coefficient and applicable to water distribution systems is presented. The present model is applied to two example problems, which were widely reported. Pipe failure analysis carried out on some of the solutions obtained revealed that the network resilience based approach gave better results in terms of network reliability.

• 대한지역사회작업치료학회지
• /
• 제4권2호
• /
• pp.31-40
• /
• 2014

목적 : 뇌졸중 환자가 요구하는 주거공간의 욕실 환경 특성을 알아보고 욕실 환경을 개선할 때 필요한 욕실 디자인 특성 선호도를 알아보았다. 연구방법 : 본 연구는 2014년 2월 24일부터 3월 13일까지 부산지역의 병원에서 재활치료를 받고 있는 뇌졸중 환자를 대상으로 설문조사를 실시하였으며 총 97부를 분석하였다. 결과 : 욕실 환경에 대한 개선 요구 조사 결과 미끄러움 방지 타일 설치($3.63{\pm}1.29$)와 욕조의 안전바 설치($3.46{\pm}1.39$)가 높게 나타났고 남자에 비해 여자의 요구도가 전반적으로 높았다. 욕실디자인 특성 선호도 조사에서 뇌졸중 환자들은 미닫이문, 미닫이형 손잡이, 편의시설형 샤워부스, 미끄러움 방지 타일, 붙박이 수납장, L자형 안전바, 자연환기(창문), 바닥 난방, 들어가기 쉬운 욕조, 안전바가 설치된 욕조, 기울어지거나 물 온도가 표시되는 세면대, 안전바형 변기, 목욕 의자를 가장 선호하는 것으로 나타났다. 결론 : 뇌졸중 환자의 욕실 환경에 대한 개선요구와 욕실디자인 특성선호도를 확인할 수 있었다. 이는 향후 뇌졸중 환자들이 요구하는 욕실디자인을 제안하는데 기초자료를 제공할 것으로 기대된다.