• Title/Summary/Keyword: NOGOOD Method

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The University Examination And Course Timetabling Problem With Integer Programming

  • Chung, Yerim;Kim, Hak-Jin
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.9
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    • pp.9-20
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    • 2019
  • In this paper, we study the university timetabling problem, which consists of two subproblems, the university course timetabling problem and the examination timetabling problem. Given a set of classrooms, students, teachers, and lectures, the problem is to assign a number of courses (and examinations) to suitable timeslots and classrooms while satisfying the given set of constraints. We discuss the modeling and solution approaches to construct course and examination timetables for one of the largest Korean university. By using binary integer programming formulations, we describe these two complex real-world problems. Then, we propose a solution method, called NOGOOD, to solve the examination timetabling model. The computation results show that NOGOOD finds the optimal examination schedule for the given instance. Although we consider a specific instance of the university timetabling problem, the methods we use can be applicable to modeling and solving other timetabling problems.

An Extended Assumption-based Truth Maintenance Method for Time Varying Situations

  • Youngwoon Woo;Han, Soo-Whan;Lee, Minsuk
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2001.06a
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    • pp.377-381
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    • 2001
  • An ATMS(Assumption-based Truth Maintenance System) has been widely used for maintaining the truth of information by detecting and solving contradictions in nile-based systems. But the ATMS can not correctly maintain the truth of the information in case that the generated information is satisfied within a time interval or includes data about temporal relations of events in time varying situations, because it has no mechanism manipulating temporal data. In this paper, The extended ATMS method is proposed, which can maintain the truth of the information in the inference system using information changing over time or temporal relations of events. In order to maintain contexts generated by relations of events, the label representation method is modified, the disjunction, conjunction simplification method in the label-propagation procedure and nogood handling method of the conventional ATMS are modified, too.

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