• 제목/요약/키워드: Task Scheduling

검색결과 484건 처리시간 0.022초

A hybrid genetic algorithm for the optimal transporter management plan in a shipyard

  • Jun-Ho Park;Yung-Keun Kwon
    • 한국컴퓨터정보학회논문지
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    • 제28권12호
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    • pp.49-56
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    • 2023
  • 본 연구에서는 트랜스포터의 할당 및 운행 순서를 최적화하기 위한 유전 알고리즘을 제안한다. 유전 알고리즘의 해는 리스트의 집합으로 표현되는데 각 리스트는 해당 트랜스포터가 작업할 순서를 나타낸다. 또한 성능 향상을 위해 효과적인 지역 탐색 연산을 결합한 혼합형 유전 알고리즘의 형태로 구현하였다. 지역 탐색 연산은 작업량이 적은 트랜스포터에서 작업의 블록을 꺼내어 다른 트랜스포터의 작업 목록에 삽입함으로써 트랜스포터 운용 대수의 감소를 유도한다. 제안하는 알고리즘의 효용성을 평가하기 위해 실제 조선소와 유사한 규모의 시뮬레이션 환경을 통해 Multi-Start 및 순수 유전알고리즘과 비교하였다. 가장 큰 규모의 문제에 대해 그들에 비해 트랜스 포터 수는 각각 40% 및 34%, 총작업 소요 시간은 27% 및 17% 감소시켰다.

도시부 가로망에서의 링크 통행속도 기반 One-to-One 최단시간 경로탐색 알고리즘 개발 (Development of One-to-One Shortest Path Algorithm Based on Link Flow Speeds on Urban Networks)

  • 김태형;김태형;박범진;김형수
    • 한국ITS학회 논문지
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    • 제11권5호
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    • pp.38-45
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    • 2012
  • 시간 종속적 가로망에 대한 최단경로 탐색은 ITS분야의 경로 일정계획과 실시간 내비게이션 시스템에서 중요한 부분을 차지한다. 본 연구에서는 매시간간격 변동적인 링크 통행속도를 고려하는 one-to-one 시간 종속적 최단시간 경로 알고리즘을 제시한다. 이를 위해, 먼저 기존의 일반적인 최단거리 경로 알고리즘 중에서 실제 도로망에서 비교적 빠르고 효율적인 알고리즘으로 알려져 있는 3가지의 알고리즘들, 즉, two queues 구조를 가진 Graph growth 알고리즘, approximate buckets 구조를 가진 Dijkstra 알고리즘, double buckets 구조를 가진 Dijkstra 알고리즘이 선택되었다. 이 알고리즘들은 모두 네트워크 내 하나의 노드에서 모든 노드(one-to-all)로의 최단거리 경로를 빠르게 탐색하기위해 개발되었다. 선택된 알고리즘들은 시간 종속적 도로망에 대해 하나의 출발노드에서 하나의 목적노드(one-to-one)로의 최단시간 경로 탐색이 가능하도록 확장된다. 또한, 제안된 3가지의 시간 종속적 최단시간 경로탐색 알고리즘들은 미국의 Anaheim, Baltimore, Chicago, Philadelphia 4개 도시의 실제 가로망에 적용하여 검증 평가된다. 결과적으로, 도시부 가로망을 대상으로 한 시간 종속적 최단시간 경로탐색 알고리즘으로 double buckets 구조를 가진 확장된 Dijkstra 알고리즘이 추천된다.

Using the METHONTOLOGY Approach to a Graduation Screen Ontology Development: An Experiential Investigation of the METHONTOLOGY Framework

  • Park, Jin-Soo;Sung, Ki-Moon;Moon, Se-Won
    • Asia pacific journal of information systems
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    • 제20권2호
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    • pp.125-155
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    • 2010
  • Ontologies have been adopted in various business and scientific communities as a key component of the Semantic Web. Despite the increasing importance of ontologies, ontology developers still perceive construction tasks as a challenge. A clearly defined and well-structured methodology can reduce the time required to develop an ontology and increase the probability of success of a project. However, no reliable knowledge-engineering methodology for ontology development currently exists; every methodology has been tailored toward the development of a particular ontology. In this study, we developed a Graduation Screen Ontology (GSO). The graduation screen domain was chosen for the several reasons. First, the graduation screen process is a complicated task requiring a complex reasoning process. Second, GSO may be reused for other universities because the graduation screen process is similar for most universities. Finally, GSO can be built within a given period because the size of the selected domain is reasonable. No standard ontology development methodology exists; thus, one of the existing ontology development methodologies had to be chosen. The most important considerations for selecting the ontology development methodology of GSO included whether it can be applied to a new domain; whether it covers a broader set of development tasks; and whether it gives sufficient explanation of each development task. We evaluated various ontology development methodologies based on the evaluation framework proposed by G$\acute{o}$mez-P$\acute{e}$rez et al. We concluded that METHONTOLOGY was the most applicable to the building of GSO for this study. METHONTOLOGY was derived from the experience of developing Chemical Ontology at the Polytechnic University of Madrid by Fern$\acute{a}$ndez-L$\acute{o}$pez et al. and is regarded as the most mature ontology development methodology. METHONTOLOGY describes a very detailed approach for building an ontology under a centralized development environment at the conceptual level. This methodology consists of three broad processes, with each process containing specific sub-processes: management (scheduling, control, and quality assurance); development (specification, conceptualization, formalization, implementation, and maintenance); and support process (knowledge acquisition, evaluation, documentation, configuration management, and integration). An ontology development language and ontology development tool for GSO construction also had to be selected. We adopted OWL-DL as the ontology development language. OWL was selected because of its computational quality of consistency in checking and classification, which is crucial in developing coherent and useful ontological models for very complex domains. In addition, Protege-OWL was chosen for an ontology development tool because it is supported by METHONTOLOGY and is widely used because of its platform-independent characteristics. Based on the GSO development experience of the researchers, some issues relating to the METHONTOLOGY, OWL-DL, and Prot$\acute{e}$g$\acute{e}$-OWL were identified. We focused on presenting drawbacks of METHONTOLOGY and discussing how each weakness could be addressed. First, METHONTOLOGY insists that domain experts who do not have ontology construction experience can easily build ontologies. However, it is still difficult for these domain experts to develop a sophisticated ontology, especially if they have insufficient background knowledge related to the ontology. Second, METHONTOLOGY does not include a development stage called the "feasibility study." This pre-development stage helps developers ensure not only that a planned ontology is necessary and sufficiently valuable to begin an ontology building project, but also to determine whether the project will be successful. Third, METHONTOLOGY excludes an explanation on the use and integration of existing ontologies. If an additional stage for considering reuse is introduced, developers might share benefits of reuse. Fourth, METHONTOLOGY fails to address the importance of collaboration. This methodology needs to explain the allocation of specific tasks to different developer groups, and how to combine these tasks once specific given jobs are completed. Fifth, METHONTOLOGY fails to suggest the methods and techniques applied in the conceptualization stage sufficiently. Introducing methods of concept extraction from multiple informal sources or methods of identifying relations may enhance the quality of ontologies. Sixth, METHONTOLOGY does not provide an evaluation process to confirm whether WebODE perfectly transforms a conceptual ontology into a formal ontology. It also does not guarantee whether the outcomes of the conceptualization stage are completely reflected in the implementation stage. Seventh, METHONTOLOGY needs to add criteria for user evaluation of the actual use of the constructed ontology under user environments. Eighth, although METHONTOLOGY allows continual knowledge acquisition while working on the ontology development process, consistent updates can be difficult for developers. Ninth, METHONTOLOGY demands that developers complete various documents during the conceptualization stage; thus, it can be considered a heavy methodology. Adopting an agile methodology will result in reinforcing active communication among developers and reducing the burden of documentation completion. Finally, this study concludes with contributions and practical implications. No previous research has addressed issues related to METHONTOLOGY from empirical experiences; this study is an initial attempt. In addition, several lessons learned from the development experience are discussed. This study also affords some insights for ontology methodology researchers who want to design a more advanced ontology development methodology.

반도체 기술 R&D 연구인력의 역량연구 -H사 기업부설연구소를 중심으로 (A Study of Competency for R&D Engineer on Semiconductor Company)

  • 윤혜림;윤관식;전화익
    • 대한공업교육학회지
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    • 제38권2호
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    • pp.267-286
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    • 2013
  • 본 연구는 반도체 제조업 회사인 H사의 기업부설연구소를 대상으로 구성원에게 필요한 역량을 규명하였다. 포커스 그룹 인터뷰와 직무분석 자료를 바탕으로 비전을 확인하고 구성원이 직무를 수행하는데 필요한 역량을 확인했다. 또한 규명된 역량에 대해 설문을 통해 구성원이 인식하고 있는 역량별 중요도인식과 역량수준을 확인함으로써 개인과 조직의 역량을 향상시키기 위한 방법을 제안하였다. 인터뷰와 직무분석은 각자 그룹별, 내용별로 정리된 후 통합 분석되었고, 분석된 결과는 Spencer&Spencer의 역량사전과 선행연구에서 개발된 역량모델들과 비교분석을 거친 뒤 유목화되어 재분류하는 과정을 거쳤으며, 그 결과 16개의 역량이 도출되었고, 7개의 역량군으로 분류하였다. 이 연구는 이러한 결과를 근거로 H사 기업부설연구소가 필요한 역량을 규명하고 직무별로 요구되는 역량의 차이를 발견하였다. 또한 역량의 중요도 인식과 역량별 본인의 수준 인식 정도를 확인하여 연구인력에 대한 보다 적극적인 교육의 방식이나 다양한 종류의 교육을 제안했다.