• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.04a
• /
• pp.314-317
• /
• 2010

본 연구는 차량 경로 스케줄링 문제(VRSPTW, the Vehicle Routing and Scheduling Problem with Time Window)를 해결하기 위하여, 멀티 비용 함수(Multi Cost Function)를 갖는 개미 군집 최적화(Ant Colony Optimization)을 이용한 휴리스틱을 제안하였다. 멀티 비용 함수는 각 개미가 다음 고객 노드로 이동하기 위해 비용을 평가할 때 거리, 요구량, 각도, 시간제약에 대해 서로 다른 가중치를 반영하여 우수한 초기 경로를 구할 수 있도록 한다. 본 연구의 실험결과에서 제안된 휴리스틱이 Solomon I1 휴리스틱과 기회시간이 반영된 하이브리드 휴리스틱보다 효율적으로 최근사 해를 얻을 수 있음을 보였다.

• KIPS Transactions on Software and Data Engineering
• /
• v.7 no.1
• /
• pp.1-8
• /
• 2018

Software testing is important to determine the reliability of the system, a task that requires a lot of effort and cost. Model-based testing has been proposed as a way to reduce these costs by automating test designs from models that regularly represent system requirements. For each path of model to generate an input value to perform a test, meta-heuristic technique is used to find the test data. In this paper, we propose an automatic test data generation method using a slicing method and a priority policy, and suppress unnecessary computation by excluding variables not related to target path. And then, experimental results show that the proposed method generates test data more effectively than conventional method.

• Journal of Information Processing Systems
• /
• v.14 no.5
• /
• pp.1237-1253
• /
• 2018

Harmony search algorithm is an emerging meta-heuristic optimization algorithm, which is inspired by the music improvisation process and can solve different optimization problems. In order to further improve the performance of the algorithm, this paper proposes an improved harmony search algorithm. Key parameters including harmonic memory consideration (HMCR), pitch adjustment rate (PAR), and bandwidth (BW) are optimized as the number of iterations increases. Meanwhile, referring to the genetic algorithm, an improved method to generate a new crossover solutions rather than the traditional mechanism of improvisation. Four complex function optimization and pressure vessel optimization problems were simulated using the optimization algorithm of standard harmony search algorithm, improved harmony search algorithm and exploratory harmony search algorithm. The simulation results show that the algorithm improves the ability to find global search and evolutionary speed. Optimization effect simulation results are satisfactory.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.11a
• /
• pp.329-332
• /
• 2006

DBMS상의 인덱싱 기법은 대부분 B-트리 또는 B-트리의 변형인 T-트리 등을 주로 사용하여 왔다. 이는 트리 구성에서 최적의 균형을 유지하여 자료검색 및 저장 공간에 효율적인 방안으로 인식되어 왔으며 대부분의 범용 DBMS에서 탁월한 성능을 보여 왔다. 그러나 고성능의 효율을 요구하는 OLTP 분야 중 특히 증권시장에서는 이런 일반적인 인덱싱 방법보다는 그 분야 특성에 맞는 새로운 인덱싱 방안의 적용이 성능 향상과 더불어 시스템의 최적의 효율을 얻어낼 수 있다. 본 논문에서는 증권시장용 원장(ledger) DB의 새로운 인덱싱 방안으로서, 먼저 원장 DB의 접근 형태를 이해하고 경험적인 데이터를 기준으로 산출한 가중치를 이용, 새로운 인덱싱 방안을 제시하고 기존 인덱싱 방법과의 비교를 통한 성능향상의 효율성을 보여준다.

• The KIPS Transactions:PartB
• /
• v.15B no.4
• /
• pp.341-346
• /
• 2008

Minimum Weight Triangulation (MWT) problem is an optimization problem searching for the triangulation of a given graph with minimum weight. Like many other graph problems this problem is also known to be NP-hard for general graphs. Several heuristic algorithms have been proposed for this problem including simulated annealing and genetic algorithm. In this paper, we propose a new genetic algorithm called GA-FF and show that the performance of the proposed genetic algorithm outperforms the previous one.

• The KIPS Transactions:PartA
• /
• v.10A no.1
• /
• pp.43-48
• /
• 2003

Two-dimensional packing algorithm can be used for allocating submeshes in mesh multiprocessor systems. Previously, we developed an efficient packing algorithm called TP heuristic, and showed how the results of the packing could be used for allocating submeshes. In this paper, we present theoretical performance bounds for TP heuristic. We also present a parallel version of the algorithm that consumes reduced time when it is executed by multiple processors in mesh multiprocessors.

• The KIPS Transactions:PartA
• /
• v.18A no.2
• /
• pp.69-74
• /
• 2011

The minimum dominating set problem of a graph G is to find a smallest possible dominating set. The minimum dominating set problem is a well-known NP-complete problem such that it cannot be solved in polynomial time. Heuristic or approximation algorithm, however, will perform well in certain area of application. In this paper, we suggest three different simulated annealing algorithms and experimentally show better efficiency improvement by applying these algorithms to the graph instances developed by DIMACS.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.8
• /
• pp.486-494
• /
• 2006

In this paper, we introduce a new solution for the load balancing problem, an important issue in parallel processing. Our heuristic load balancing technique called MGA effectively combines the benefit of both mean-field annealing (MFA) and genetic algorithms (GA). We compare the proposed MGA algorithm with other mapping algorithms (MFA, GA-l, and GA-2). A multiprocessor mapping algorithm simulation has been developed to measure performance improvement ratio of these algorithms. Our experimental results show that our new technique, the composition of heuristic mapping methods improves performance over the conventional ones, in terms of solution quality with a longer run time.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.28 no.1
• /
• pp.92-96
• /
• 2005

This paper deals with a batch processor model in which the batch processing times depend on the jobs assigned to the batch. Each job has a distinct processing time which is determined as not the exact value but the range from the lower limit to the upper, which makes it possible to group several jobs into the same batch. In point of this flexibility our model can be referred to as the generalization of the bum-in model in which the upper limit of each job is unbounded. The jobs to be scheduled may be available nonsimultaneously. Therefore they have different ready times. We develop the model to describe the problem situation and the heuristic methods to minimize the total tardiness. And our batching rule is compared with other dispatching ones.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.04a
• /
• pp.507-510
• /
• 2001

HTTP/1.1 standard reduces latencies and overhead from closing and re-establishing connections by supporting persistent connections as a default, which encourage multiple transfers of objects over one connection. HTTP/1.1, however, does not define explicitly connection-closing time but specifies a certain fixed holding time model. This model may induce wasting server's resource when server maintains conn ection with the idle-state client that requests no data for a certain time. This paper proposes the mechanism of a heuristic connection management supported by the client-side under persistent HTTP, in addition to HTTP/1.1's fixed holding time model on server-side. The client exploits the tag information within transferred HTML page so that decides connection-closing time. As a result, the mechanism allows server to use server's resource more efficiently without server's efforts.