• Title/Summary/Keyword: combinatorial approach

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Reviews of Bus Transit Route Network Design Problem (버스 노선망 설계 문제(BTRNDP)의 고찰)

  • Han, Jong-Hak;Lee, Seung-Jae;Lim, Seong-Su;Kim, Jong-Hyung
    • Journal of Korean Society of Transportation
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    • v.23 no.3 s.81
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    • pp.35-47
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    • 2005
  • This paper is to review a literature concerning Bus Transit Route Network Design(BTRNDP), to describe a future study direction for a systematic application for the BTRNDP. Since a bus transit uses a fixed route, schedule, stop, therefore an approach methodology is different from that of auto network design problem. An approach methodology for BTRNDP is classified by 8 categories: manual & guideline, market analysis, system analytic model. heuristic model. hybrid model. experienced-based model. simulation-based model. mathematical optimization model. In most previous BTRNDP, objective function is to minimize user and operator costs, and constraints on the total operator cost, fleet size and service frequency are common to several previous approach. Transit trip assignment mostly use multi-path trip assignment. Since the search for optimal solution from a large search space of BTRNDP made up by all possible solutions, the mixed combinatorial problem are usually NP-hard. Therefore, previous researches for the BTRNDP use a sequential design process, which is composed of several design steps as follows: the generation of a candidate route set, the route analysis and evaluation process, the selection process of a optimal route set Future study will focus on a development of detailed OD trip table based on bus stop, systematic transit route network evaluation model. updated transit trip assignment technique and advanced solution search algorithm for BTRNDP.

Hypernetwork Classifiers for Microarray-Based miRNA Module Analysis (마이크로어레이 기반 miRNA 모듈 분석을 위한 하이퍼망 분류 기법)

  • Kim, Sun;Kim, Soo-Jin;Zhang, Byoung-Tak
    • Journal of KIISE:Software and Applications
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    • v.35 no.6
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    • pp.347-356
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    • 2008
  • High-throughput microarray is one of the most popular tools in molecular biology, and various computational methods have been developed for the microarray data analysis. While the computational methods easily extract significant features, it suffers from inferring modules of multiple co-regulated genes. Hypernetworhs are motivated by biological networks, which handle all elements based on their combinatorial processes. Hence, the hypernetworks can naturally analyze the biological effects of gene combinations. In this paper, we introduce a hypernetwork classifier for microRNA (miRNA) profile analysis based on microarray data. The hypernetwork classifier uses miRNA pairs as elements, and an evolutionary learning is performed to model the microarray profiles. miTNA modules are easily extracted from the hypernetworks, and users can directly evaluate if the miRNA modules are significant. For experimental results, the hypernetwork classifier showed 91.46% accuracy for miRNA expression profiles on multiple human canters, which outperformed other machine learning methods. The hypernetwork-based analysis showed that our approach could find biologically significant miRNA modules.

Performance Improvement of Cooperating Agents through Balance between Intensification and Diversification (강화와 다양화의 조화를 통한 협력 에이전트 성능 개선에 관한 연구)

  • 이승관;정태충
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.40 no.6
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    • pp.87-94
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    • 2003
  • One of the important fields for heuristic algorithm is how to balance between Intensification and Diversification. Ant Colony Optimization(ACO) is a new meta heuristic algorithm to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as Breedy search It was first Proposed for tackling the well known Traveling Salesman Problem(TSP). In this paper, we deal with the performance improvement techniques through balance the Intensification and Diversification in Ant Colony System(ACS). First State Transition considering the number of times that agents visit about each edge makes agents search more variously and widen search area. After setting up criteria which divide elite tour that receive Positive Intensification about each tour, we propose a method to do addition Intensification by the criteria. Implemetation of the algorithm to solve TSP and the performance results under various conditions are conducted, and the comparision between the original An and the proposed method is shown. It turns out that our proposed method can compete with the original ACS in terms of solution quality and computation speed to these problem.

Diagnosing Multiple Faults using Multiple Context Spaces (다중 상황공간을 이용한 다중 오류의 고장 진단)

  • Lee, Gye-Sung;Gwon, Gyeong-Hui
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.1
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    • pp.137-148
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    • 1997
  • Diagnostic problem solving is a major application area of knowledge-based systems research. However, most of the current approaches, both heuristic and model-based, are designed to identify single faults, and do not generalize easily to multiple fault diagnosis without exhibiting exponential behavior in the amount of computation required. In this paper, we employ a decomposition approach based on system configuration to generate an efficient algorithm for multiple fault diagnosis. The basic idea of the algorithm is to reduce the inherent combinatorial explosion that occurs in generating multiple faults by partitioning the circuit into groups that correspond to output measurement points. Rules are multiple faults by partitioning the circuit into groups that correspond to output measurement points. rules are developed for combining candidates from individual groups, and forming consistent sets of minimal candidates.

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Multi Colony Ant Model using Positive.Negative Interaction between Colonies (집단간 긍정적.부정적 상호작용을 이용한 다중 집단 개미 모델)

  • Lee, Seung-Gwan;Chung, Tae-Choong
    • The KIPS Transactions:PartB
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    • v.10B no.7
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    • pp.751-756
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    • 2003
  • Ant Colony Optimization (ACO) is new meta heuristics method to solve hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was firstly proposed for tackling the well known Traveling Salesman Problem (TSP) . In this paper, we introduce Multi Colony Ant Model that achieve positive interaction and negative interaction through Intensification and Diversification to improve original ACS performance. This algorithm is a method to solve problem through interaction between ACS groups that consist of some agent colonies to solve TSP problem. In this paper, we apply this proposed method to TSP problem and evaluates previous method and comparison for the performance and we wish to certify that qualitative level of problem solution is excellent.

Elite Ant System for Solving Multicast Routing Problem (멀티캐스트 라우팅 문제 해결을 위한 엘리트 개미 시스템)

  • Lee, Seung-Gwan
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.3
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    • pp.147-152
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    • 2008
  • Ant System(AS) is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, AS is applied to the Multicast Routing Problem. Multicast Routing is modeled as the NP-complete Steiner tree problem. This is the shortest path from source node to all destination nodes. We proposed new AS to resolve this problem. The proposed method selects the neighborhood node to consider all costs of the edge and the next node in state transition rule. Also, The edges which are selected elite agents are updated to additional pheromone. Simulation results of our proposed method show fast convergence and give lower total cost than original AS and $AS_{elite}$.

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Ant Colony System for solving the traveling Salesman Problem Considering the Overlapping Edge of Global Best Path (순회 외판원 문제를 풀기 위한 전역 최적 경로의 중복 간선을 고려한 개미 집단 시스템)

  • Lee, Seung-Gwan;Kang, Myung-Ju
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.3
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    • pp.203-210
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    • 2011
  • Ant Colony System is a new meta heuristics algorithms to solve hard combinatorial optimization problems. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, we propose the searching method to consider the overlapping edge of the global best path of the previous and the current. This method is that we first determine the overlapping edge of the global best path of the previous and the current will be configured likely the optimal path. And, to enhance the pheromone for the overlapping edges increases the probability that the optimal path is configured. Finally, the performance of Best and Average-Best of proposed algorithm outperforms ACS-3-opt, ACS-Subpath and ACS-Iter algorithms.

A Case Study on BIM-enabled Evaluation of Design Alternatives for an Actual Remodeling Project in Korea - Focusing on the Spatial Program Review in Early Phase of Design -

  • Kim, Hyunjung;Lee, Jin-Kook
    • Korean Institute of Interior Design Journal
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    • v.24 no.5
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    • pp.117-127
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    • 2015
  • This paper depicts a case study of the BIM (Building Information Modeling)-enabled evaluation of design alternatives for an actual remodeling project in Yeongwol, Korea. The increase of urban population and income followed by the growth of economy has derived massive supply of grand scale housing project in Korea since 1970s. Consequently, building remodeling became one of the feasible resolutions for renovating such old housings in these days. This paper aims to introduce a technical approach to such remodeling projects based on BIM-enabled applications focusing on quantitative analysis of design alternatives. Among the technical issues of such building remodeling projects, this paper focuses on the BIM-enabled area analysis and comparison between design alternatives to support decision-making even in early phase of remodeling design process. BIM and its variety of applications have broadly influenced the domain of AEC-FM (Architecture, Engineering, Construction, and Facility Management) within the lifecycle of buildings. As one of the applications facilitated by BIM, the automated area calculation and scenario-based comparison between alternatives can play an important role in the early phase of remodeling project. We modeled three design alternatives (buildings) and three housing modules (units) based on the actual case in Yeongwol city, Korea using a BIM design authoring tool. Nine combinatorial BIM models were demonstrated for the BIM-enabled review process described in this paper. To determine the most optimal design scenario among nine alternatives, this paper demonstrates a result of the conducted spatial program review. The main subject includes specific spatial program issues on; 1) the number of unit spaces; and 2) area of individual/grouped and private/shared spaces.

Hybrid Techniques for Standard Cell Placement (표준 셀 배치를 위한 하이브리드 기법)

  • 허성우;오은경
    • Journal of KIISE:Computer Systems and Theory
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    • v.30 no.10
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    • pp.595-602
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    • 2003
  • This Paper presents an efficient hybrid techniques for a standard cell placement. The prototype tool adopts a middle-down methodology in which an n${\times}$m grid is imposed over the layout area and cells are assigned to bins forming a global placement. The optimization technique applied in this phase is based on the Relaxation-Based Local Search (RBLS) framework [12]in which a combinatorial search mechanism is driven by an analytical engine. This enables a more global view of the problem and results in complex modifications of the placement in a single search“move.”Details of this approach including a novel placement legalization procedure are presented. When a global placement converges, a detailed placement is formed and further optimized by the optimal interleaving technique[13]. Experimental results on MCNC benchmarking circuits are presented and compared with the Feng Shui's results in[14]. Solution Qualifies are almost the same as the Feng Shui's results.

The Ant Algorithm Considering the Worst Path in Traveling Salesman problems (순회 외판원 문제에서 최악 경로를 고려한 개미 알고리즘)

  • Lee, Seung-Gwan;Lee, Dae-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.12
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    • pp.2343-2348
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    • 2008
  • Ant algorithm is new meta heuristic for hard combinatorial optimization problem. It is a population based approach that uses exploitation of positive feedback as well as greedy search. It was first proposed for tackling the well known Traveling Salesman Problem. In this paper, we propose the improved $AS_{rank}$ algorithms. The original $AS_{rank}$ algorithm accomplishes a pheromone updating about only the paths which will be composed of the optimal path is higher, but, the paths which will be composed the optimal path is lower does not considered. In this paper, The proposed method evaporate the pheromone of the paths which will be composed of the optimal path is lowest(worst tour path), it is reducing the probability of the edges selection during next search cycle. Simulation results of proposed method show lower average search time and average iteration than original ACS.