• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.11B
• /
• pp.663-672
• /
• 2007

This paper proposes an algorithm for design of a multiple ring network that can be applied to an arbitrary topology in the WDM optical transport networks. Especially, we suggest an integer linear program(ILP) formulation with the objective of minimizing the total cost of nodes based on the reconfigurable OADM(ROADM) architecture and propose a heuristic algorithm to reduce computational complexity of the exact problem formulation. To evaluate the performance and validity of this scheme, we applied it to an NSFnet topology assuming the dynamic or static traffic condition and compared it with a mesh methodology about capacity of connection requests and the total cost of the nodes.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.8
• /
• pp.590-598
• /
• 2019

Today, satellites are widely used in many fields like communication and image recoding. The image acquired by satellites contains variety information of wide region. Therefore, they are used for agriculture, resource exploitation and management, and military purpose. The satellite is required to acquire images effectively in a given time period. Because the period that satellites can acquire images is very restrictive. In this study, the modeling of processing time and attitude maneuvering for satellite image acquisition is performed. From this modeling, mission planning algorithm using heuristic evaluation function is suggested and performance of the proposed algorithm is verified by numerical simulation.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2004.05a
• /
• pp.397-400
• /
• 2004

본 논문에서는 Navigation Mesh로 이루어진 3D 게임에서 가시성 그래프(Visibility Graph)와 $A^*$ 알고리즘을 혼용한 효율적인 경로 탐색 방법을 제안한다. Navigation Mesh로 지형을 생성할 때 이동에 꼭 필요한 Mesh로만 최대한 단순하게 지형을 구성하는 경우에는 경로 탐색을 위하여 $A^*$ 알고리즘을 적용할 수 있으나, 일반적으로 세밀하게 구성된 Navigation Mesh에서 $A^*$ 알고리즘을 적용할 경우 탐색할 공간이 많아지기 때문에 경로 탐색이 매우 비효율적이 된다. 세밀하게 구성된 Navigation Mesh에서도 효율적인 탐색을 하기 위해서 본 논문에서는 가시성 그래프를 이용하여 탐색 공간을 줄이는 방법을 사용하였다. 장애물들의 정점을 찾아 반드시 통과하여야 하는 mesh 들을 선정하고 $A^*$의 휴리스틱 함수를 이 mesh들을 지나가는 거리로 정의함으로써 기본적인 $A^*$ 알고리즘을 수행하는 것보다 탐색을 위하여 방문하는 mesh들의 수를 현저히 줄일 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.353-353
• /
• 2020

기후변화에 적응하기 위해 많은 나라들이 수자원 관리 전략을 마련하고 있으며, 대체 수자원 활성화 방안에 관심을 기울이고 있다. 본 연구에서는 대체 수자원 활성화 방안 중 빗물 저류지의 용량 결정 방법을 제시하고자 한다. 빗물 저류지의 용량을 결정하기 위해 메타 휴리스틱 방법 중 하나인 입자 군집 최적화(particle swarm optimization; PSO)를 선정하였다. 이는 기존 실제 설계에 사용되고 있는 시행착오법보다 시간을 단축시킬 수 있다. 최적화 모형은 python의 pyswarm package를 이용해 구성하였다. 모형의 입력자료는 저류지 유입량과 목표 공급량, 목표 보장률이고, 목적함수는 빗물 저류지 용량의 최소화이다. 제약조건은 모의된 보장률이 목표 보장률 이상을 달성하는 것이다. 여기서, 보장률은 전체 모의 기간 중 목표 공급량을 공급한 기간의 비율이다. 제시한 방법론의 적용성을 검토하기 위해 실제 저류지가 설계된 인천의 청라지구 1공구를 선정하여 적용하였다. 최적화 모형의 입력 유입량은 SWMM으로 산정된 1995년부터 2004년까지의 유출량이며, 목표 공급량은 실제 설계에 활용된 용수 목적별 요구 수량이다. 여기서 용수 목적별 요구 수량은 대상지역의 노면 청소수, 화장실 세정수, 호수 유지수 등이다. 산정 결과 계산 시간은 약 30초 소요되며, 목표 보장률을 만족하는 저류지 용량이 결정되었다. 본 연구에 제시한 방법은 제약조건이 추가되어도 기존 시행착오법에 비해 간편함을 확인하였다.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.28 no.3
• /
• pp.183-192
• /
• 2022

With the growth of the packaging industry, demand on the packaging printing comes in various forms. Customers' orders are diversifying and the standards for quality are increasing. Offset printing is mainly used in the packaging printing since it is easy to print in large quantities. However, productivity of the offset printing decreases when printing various order. This is because it takes time to change colors for each printing unit. Therefore, scheduling that minimizes the color replacement time and shortens the overall makespan is required. By the existing manual method based on workers' experience or intuition, scheduling results may vary for workers and this uncertainty increase the production cost. In this study, we propose an automated scheduling method of parallel offset printing process for packaging printing. We decompose the original problem into assigning and sequencing orders, and ink arrangement for printing problems. Vehicle routing problem and assignment problem are applied to each part. Mixed integer programming is used to model the problem mathematically. But it needs a lot of computational time to solve as the size of the problem grows. So guided local search algorithm is used to solve the problem. Through actual data experiments, we reviewed our method's applicability and role in the field.

• The KIPS Transactions:PartB
• /
• v.11B no.2
• /
• pp.221-226
• /
• 2004

Ant Colony System(ACS) Algorithm is new meta-heuristic for hard combinational optimization problem. It is a population-based approach that uses exploitation of positive feedback as well as greedy search. Recently, various methods and solutions are proposed to solve optimal solution of graph coloring problem that assign to color for adjacency node($v_i, v_j$) that they has not same color. In this paper introducing ANTCOL Algorithm that is method to solve solution by Ant Colony System algorithm that is not method that it is known well as solution of existent graph coloring problem. After introducing ACS algorithm and Assignment Type Problem, show the wav how to apply ACS to solve ATP And compare graph coloring result and execution time when use existent generating functions(ANT_Random, ANT_LF, ANT_SL, ANT_DSATUR, ANT_RLF method) with ANT_XRLF method that use XRLF that apply Randomize to RLF to solve ANTCOL. Also compare graph coloring result and execution time when use method to add re-search to ANT_XRLF(ANT_XRLF_R) with existent generating functions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.7
• /
• pp.4999-5008
• /
• 2015

The application of efficient constraint handling technique is fundamental method to find better solutions in engineering optimization problems with constraints. In this research four of constraint handling techniques are used with a meta-heuristic optimization method, harmony search algorithm, and the efficiency of algorithm is evaluated. The sample problem for evaluation of effectiveness is one of the typical discrete problems, optimal pipe size design problem of water distribution system. The result shows the suggested constraint handling technique derives better solutions than classical constraint handling technique with penalty function. Especially, the case of ${\varepsilon}$-constrained method derives solutions with efficiency and stability. This technique is meaningful method for improvement of harmony search algorithm without the need for development of new algorithm. In addition, the applicability of suggested method for large scale engineering optimization problems is verified with application of constraint handling technique to big size problem has over 400 of decision variables.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.2
• /
• pp.82-90
• /
• 2002

BDD have become widely used for various CAD applications because Boolean functions can be represented uniquely and compactly by using BDD. The size of the BDD representation for a function is very sensitive to the choice of orderings on the input variable. Therefore, it is very important to find a good variable ordering which minimize the size of the BDD. Since finding an optimal ordering is NP-complete, several heuristic algorithms have been proposed to find good variable orderings. In this paper, we propose a variable ordering algorithm, Faster-${\mu}$0, based on the ${\mu}$0(microcanonical optimization). In the Faster-${\mu}$0 algorithm, the initialization phase is replaced with a shifting phase to produce better solutions in a fast local search. We find values for algorithm parameters experimentally and the proposed algorithm has been experimented on well known benchmark circuits and shows superior performance compared to various existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.11
• /
• pp.2886-2896
• /
• 1996

The Type of Service based multicast routing algorithm is necessary to support efficiently herogeneous applications in ATM network. In this paper I propose the Constrained Multicast Tree with Virtual Destination(DMTVD) heuristic algorithm as least cost multicast routing algorithm. The service is categorized into two types, as delay sensitive and non in CMTVD algorithm. For the delay sensitive service type, the cost optimized route is the Minimum Cost Stenier Tree connecting all the destination node group, virtual destination node group and source node with least costs, subject to the delay along the path being less than the maximum allowable end to end delay. The other side for the non-delay sensitive service, the cost optimized route is the MCST connecting all the multicast groups with least costs, subject to the traffic load is balanced in the network. The CMTVD algorithm is based on the Constrained Multicasting Tree algorithm but regards the nodes branching multiple destination nodes as virtural destination node. The experimental results show that the total route costs is enhanced 10%-15% than the CTM algorithm.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.4
• /
• pp.95-102
• /
• 2015

This paper proposes a simple algorithm for circuit minimization. There are currently two effective heuristics for circuit minimization, namely manual Karnaugh maps and computable Quine-McCluskey algorithm. The latter, however, has a major defect: the runtime and memory required grow $3^n/n$ times for every increase in the number of variables n. The proposed algorithm, however, extracts the prime implicants (PI) that cover minterms of a given Boolean function by deriving an implicants table based on frequency. From a set of the extracted prime implicants, the algorithm then eliminates redundant PIs again based on frequency. The proposed algorithm is therefore capable of minimizing circuits polynomial time when faced with an increase in n. When applied to various 3-variable and 4-variable cases, it has proved to swiftly and accurately obtain the optimal solutions.