• 한국항공우주학회지
• /
• 제38권5호
• /
• pp.427-436
• /
• 2010

본 논문은 다수의 목표물과 다수의 임무가 존재하는 상황에서의 다수 무인항공기의 임무할당 문제를 다룬다. 다수 무인항공기의 임무할당 문제는 순회 세일즈맨 문제, 차량 라우팅 문제와 같은 조합최적화 문제의 일종으로 NP-hard의 계산 복잡도를 가지고 있다. 이런 성격의 문제는 문제의 크기가 커질수록 계산시간이 급격히 증가하는 특징을 지니기 때문에 문제를 효율적으로 풀기 위해서 근사화 방법 또는 발견적인 방법을 사용한다. 본 연구에서는 임무할당 문제를 혼합정수 선형계획 문제로 정식화하고, 혼합정수 선형계획법과 유전 알고리듬으로 해를 구하였다. 다수의 목표물, 다수의 임무, 장애물이 존재하는 환경에 대한 수치 시뮬레이션을 수행하여 각 방법의 최적성과 효율성에 대해 검토하였다.

• 경영과학
• /
• 제32권1호
• /
• pp.49-63
• /
• 2015

This paper investigates an aircraft-target assignment problem in consideration of deconfliction. The aircraft-target assignment problem is the problem to assign available aircrafts and weapons to targets that should be attacked, where the objective function is to minimize the total expected damage of aircrafts. Deconfliction is the way of dividing airspaces for aircraft flight to ensure the safety while performing the mission. In this paper, mixed integer programming model is suggested, where it considers deconfliction between aircrafts. However, the suggested MIP model is non-linear and limited to get solution for large size problem. The 2-phase decomposition model is suggested for efficiency and computation, where in the first phase target area is divided into sectors for deconfliction and in the second phase aircrafts and weapons are assigned to given targets for minimizing expected damage of aircraft. The proposed decomposition model shows outperforms the model developed for comparison in the computational experiment.

• ETRI Journal
• /
• 제21권4호
• /
• pp.9-22
• /
• 1999

This paper considers a problem of configuring both physical backbone and logical virtual path (VP) networks in a reconfigurable asynchronous transfer mode (ATM) network where links are subject to failures. The objective is to determine jointly the VP assignment, the capacity assignment of physical links and the bandwidth allocation of VPs, and the routing assignment of traffic demand at least cost. The network cost includes backbone link capacity expansion cost and penalty cost for not satisfying the maximum throughput of the traffic due to link failures or insufficient link capacities. The problem is formulated as a zero-one non-linear mixed integer programming problem, for which an effective solution procedure is developed by using a Lagrangean relaxation technique for finding a lower bound and a heuristic method exploited for improving the upper bound of any intermediate solution. The solution procedure is tested for its effectiveness with various numerical examples.

• 한국군사과학기술학회지
• /
• 제20권3호
• /
• pp.441-453
• /
• 2017

In this paper, a new type of weapon-target assignment(WTA) problem has been suggested that reflects realistic constraints for sharing target with other weapons and shooting double rapid fire. To utilize in rapidly changing actual battle field, the computation time is of great importance. Several metaheuristic methods such as Simulated Annealing, Tabu Search, Genetic Algorithm, Ant Colony Optimization, and Particle Swarm Optimization have been applied to the real-time WTA in order to find a near optimal solution. A case study with a large number of targets in consideration of the practical cases has been analyzed by the objective value of each algorithm.

• 한국경영과학회지
• /
• 제27권4호
• /
• pp.1-10
• /
• 2002

The ring routing and wavelength assignment problem arose in the planning of optical communication networks which use WDM rings. Traffic demands are given for each pair of nodes in an ring : each demand must be routed one of the two possible connections round the ring and the wavelength assignments must be made so that there are no conflicts : that is. no two connections whose routes share a link can be assigned the same wavelength along that link. The objective is to minimize the number of used wavelengths. We propose the local optimal routing for the problem and show that there always exists an optimal solution satisfying it. Furthermore we suggest a new lower bound for the problem and show that it is very efficient for the worst case example.

• 한국컴퓨터정보학회논문지
• /
• 제21권2호
• /
• pp.97-103
• /
• 2016

This paper deals with the cycle time minimization problem that determines the productivity in printed circuit board (PCB) with n components using the m placement machines. This is known as production cycle time determination problem (PCTDP). The polynomial time algorithm to be obtain the optimal solution has been unknown yet, therefore this hard problem classified by NP-complete. This paper gets the initial assignment result with the machine has minimum unit placement time per each component firstly. Then, the balancing process with reallocation from overhead machine to underhead machine. Finally, we perform the swap optimization and get the optimal solution of cycle time $T^*$ within O(mn) computational complexity. For experimental data, the proposed algorithm can be obtain the same result as integer programming+branch-and-bound (IP+B&B) and B&B.

• 전기의세계
• /
• 제31권3호
• /
• pp.209-217
• /
• 1982

This paper considers a finite spectrum assignment Problem for a functional retarded linear differential system with delays in control only. In this problem, by generalizing from an abstract linear system characterized by Semigroups on a Hilbert space to a finite dimensional linear system, we unify the relationship between a control-delayed system and its non-delayed system, and then by using the spectrum of the generator-decomposition of Semigroup, we try to get a feedback law which yields a finite spectrum of the closed-loop system, located at an arbitrarily preassigned sets of n points in the complex plane. The comparative examinations between the standard spectrum assignment method and the method of spectral projection for the feedback law which consists of proportional and finite interval terms over present and past values of control variables are also considered. The analysis is carry down to the elementary spectral projection level because, in spite of all the research efforts, so far there has been no significant attempt to obtain the feedback implementation directly from the abstract representation forms in the case of multivariables.

• Journal of Information Technology Applications and Management
• /
• 제13권2호
• /
• pp.29-39
• /
• 2006

There has been a tremendous need for dual homing cell switch assignment problems where calling volume and patterns are different at different times of the day. This problem of assigning cells to switches in the planning phase of mobile networks consists in finding an assignment plan which minimizes the communication costs taking into account some constraints such as capacity of switches. This optimization problem is known to be difficult to solve, such that heuristic methods are usually utilized to find good solutions in a reasonable amount of time. In this paper, we propose an evolutionary approach, based on the genetic algorithm paradigm, for solving this problem. Simulation results confirm the appropriateness and effectiveness of this approach which yields solutions of good quality.

• 산업공학
• /
• 제22권2호
• /
• pp.116-125
• /
• 2009

We revisit the assembly block storage location assignment problem (ABSLAP) at a shipyard, in order to compensate for the deficiency in performance verification of the heuristic ABSLAP algorithm developed by the previous study. In this paper, we formulate a mathematical programming model of the ABSLAP, refine elaborately the heuristic ABSLAP algorithm, and show the performance of the developed mathematical programming model and the revised heuristic ABSLAP algorithm. In addition, we explain simulation experiments conducted using the revised heuristic ABSLAP algorithm to investigate the influences of block stockyard layouts and production schedule instability on the block stockyard operations.

• 대한교통학회지
• /
• 제24권2호
• /
• pp.169-178
• /
• 2006

통행배정 (traffic assignment)은 장래 통행수요를 예측할 뿐 아니라. 교통혼잡을 완화시키는 각종 교통정책들을 사전에 평가하는 도구로 그 활용범위가 넓어지고 있다. 현재 대표적인 통행배정방법은 Wardrop(1952)이 제시한 사용자 균형원리 (user equilibrium principle)에 따라 통행자를 교통망에 배정하는 방법으로 동등 수리최소화모형 (equivalent mathematical minimization model), 변동부등식 (Variational inequality), 비선형상보문제 (Nonlinear Complementary Problem), 고정점 모형(fixed point method) 등이 있다. 그런데, 최근 Jin(2005a)은 동적과정(dynamic process)에 기초하여 사용자 균형해를 구할 수 있는 새로운 모형을 제시하였다. 본 연구는 Jin이 제시한 모형에 대한 효과적인 알고리듬을 개발하고 이를 평가하는 데 연구의 목적이 있다. 개발된 알고리듬은 통행배정모형을 풀기 위하여 현재 널리 사용되는 Frank-Wolfe방법보다 쉽게 프로그램화 할 수 있는데, 목적함수를 평가(evaluation)하는 단계가 불필요하며 축차적인 계산과정을 통하여 해를 구하기 때문이다. 제시된 알고리듬을 예제 교통망을 대상으로 분석한 결과, 사용자 균형해(user equilibrium)를 도출함을 확인할 수 있었다.