• 한국컴퓨터정보학회논문지
• /
• 제18권6호
• /
• pp.37-45
• /
• 2013

통신채널 최적 할당 문제는 아직까지 결정론적 규칙이 알려지지 않고 있어 비결정론적 방법인 휴리스틱 알고리즘으로 대부분 해를 구하고 있다. 본 논문은 통신채널 최적 할당 문제에 대해 결정론적 방법으로 채널 배정을 할 수 있음을 보인다. 채널 배정 규칙을 적용하여 필라델피아의 9개 사례에 대해 적용한 결과 최적해를 구하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.290-295
• /
• 1989

This paper proposes a Expert CAPP System for integrating CAD/CAM of rotational work-part by rule based approach. The CAD/CAPP integration is performed by the recognition of machined features from the 2-D CAD data (IGES) file. Selecting functions of the process planning are performed in modularized rule base by forward chaining inference, and operation sequences are determined by means of heuristic search algorithm. For CAPP/CAM integration, post-processor generates NC code from route sheet file. This system coded in OPS5 and C language on PC/AT, and EMCO CNC lathe interfaced with PC through DNC and RS-232C.

• 한국지능시스템학회논문지
• /
• 제14권1호
• /
• pp.15-19
• /
• 2004

개미군락시스템 (Ant Colony System, ACS)은 조합 최적화 문제를 해결하기 위한 기법으로 생물학적 기반의 메타휴리스틱 접근법이다. 지나간 경로에 대하여 페로몬을 분비하고 통신 매개물로 사용하는 실제 개미들의 추적 행위를 기반으로 한다. 최적 경로를 찾기 위해서는 보다 다양한 에지들에 대한 탐색이 필요하다. 기존 개미군락시스템의 지역 갱신 규칙에서는 지나간 에지에 대하여 고정된 페로몬 갱신 값을 부여하고 있다. 그러나 본 논문에서는 방문한 도시간의 거리와 해당 에지의 방문 횟수를 이용하여 페로몬을 부여한다. 보다 많은 정보를 탐색에 활용함으로써 기존의 방법에 비해 지역 최적화에 빠지지 않고 더 나은 해를 찾을 수 있었다.

• 산업공학
• /
• 제12권4호
• /
• pp.617-624
• /
• 1999

In order to maximize an availability of machine and utilization of space, the parallel machines scheduling problem with space limit is frequently discussed in the industrial field. In this paper, we consider a scheduling problem for assembly machine in ship engine assembly shop. This paper considers the parallel machine scheduling problem in which n jobs having different release times, due dates and space limits are to be scheduled on m parallel machines. The objective function is to minimize the sum of earliness and tardiness. To solve this problem, a heuristic is developed. The proposed heuristic is divided into three modules hierarchically: job selection, machine selection and job sequencing, solution improvement. To illustrate its effectiveness, a proposed heuristic is evaluated with a large number of randomly generated test problems based on the field situation. Through the computational experiment, we determine the job selection rule that is suitable to the problem situation considered in this paper and show the effectiveness of our heuristic.

• 한국국방경영분석학회지
• /
• 제17권2호
• /
• pp.90-99
• /
• 1991

In this paper a dispatching rule, $D^{*}$, for AGV operations in automated manufacturing system is proposed to improve the performance measures. And the algorithm is compared with existing heuristic rules via simulation to evaluate its capabilities. It is shown that the proposed rule enhances mean flow time, makespan and throughput, and avoids the locking phenominon which can be fatal to the operation of automated manufacturing systems.

• 산업공학
• /
• 제15권4호
• /
• pp.338-348
• /
• 2002

In this paper, we present a restricted tabu search(RTS) algorithm that schedules jobs on identical parallel machines in order to minimize the maximum lateness of jobs. Jobs have release times and due dates. Also, sequence-dependent setup times exist between jobs. The RTS algorithm consists of two main parts. The first part is the MATCS(Modified Apparent Tardiness Cost with Setups) rule that provides an efficient initial schedule for the RTS. The second part is a search heuristic that employs a restricted neighborhood generation scheme with the elimination of non-efficient job moves in finding the best neighborhood schedule. The search heuristic reduces the tabu search effort greatly while obtaining the final schedules of good quality. The experimental results show that the proposed algorithm gives better solutions quickly than the existing heuristic algorithms such as the RHP(Rolling Horizon Procedure) heuristic, the basic tabu search, and simulated annealing.

• 대한산업공학회지
• /
• 제34권3호
• /
• pp.318-327
• /
• 2008

This paper considers a single-machine scheduling problem with availability constraints. In many realistic situations, machines may not be always available due to various reasons such as maintenance, breakdown and repair. However, most literature on scheduling assume that the machines are available at all times. This paper deals with a single-machine scheduling problem with periodic maintenance. If the maintenance decision is made jointly with the job scheduling, the system will be more effective. The objective is to minimize the total completion time of jobs. This problem is proved to be NP-hard in the strong sense. The proposed breaking heuristic(BH) algorithm rule is established by some theorems and conditions. Our computational results show that the BH algorithm is much more efficient than existing heuristic.

• 경영과학
• /
• 제24권2호
• /
• pp.43-56
• /
• 2007

VRP(Vehicle Routing Problem) is studied in this paper, where two different kinds of missions are to be completed. The objective is to minimize the total vehicle operating distance. A mixed integer programming formulation and a heuristic algorithm for a practical use are suggested. A heuristic algorithm consists of three phases such as clustering, constructing routes, and adjustment. In the first phase, customers are clustered so that the supply nodes are grouped with demand nodes to be served by the same vehicle. Vehicle routes are generated within the cluster in the second phase. Clusters and routes are adjusted in the third phase using the UF (unfitness) rule designed to determine the customers and the routes to be moved properly. It is shown that the suggested heuristic algorithm yields good performances within a relatively short computational time through computational experiment.

• 제어로봇시스템학회논문지
• /
• 제9권8호
• /
• pp.623-631
• /
• 2003

We have fabricated the two-dimensional inverted pendulum system and designed its controller. The two-dimensional inverted pendulum system, which is composed of X-Y table, is actuated through timing belt by each of two geared DC motors. And the control goal is that the rod is always kept to a vertical position to any distrubance and is quickly moved to the desired position. Because this system has generally nonlinear dynamic characteristics and X-axis and Y-axis move together, it is very difficult to find its exact mathematical model and to design its controller. Therefore, we have designed the PID controller with simple structure and excellent performance. Genetic algorithm(GA), which is blown as one of probabilistic searching methods, and human's heuristic control strategy are introduced to design an optimal PID controller. The usefulness of the proposed GA based PID coefficient searching technique is verified through the experiments and computer simulations.

• 산업경영시스템학회지
• /
• 제24권64호
• /
• pp.21-28
• /
• 2001

This paper suggests a new heuristic to improve robotic cells efficiency with a finite buffer. An efficient heuristic for parts sequencing with this configuration is developed. Analyzing robot\\`s movements and defining the events for the completion times of robot\\`s segmental activities enable us to develop a mathematical model that can be used to estimate, the completion time in the robotic cell. The robotic cell is consisting of two computer numerical control machines and a finite buffer to manufacture multiple parts. The developed heuristic can be used to estimate an optimum or near optimum parts sequences for this configuration. Numerical examples are followed to show the validity of the heuristic.