AI帮你理解科学

AI 生成解读视频

AI抽取解析论文重点内容自动生成视频


pub
生成解读视频

AI 溯源

AI解析本论文相关学术脉络


Master Reading Tree
生成 溯源树

AI 精读

AI抽取本论文的概要总结


微博一下
We introduced the probability of existence of an activity and used it to represent that an activity in the original problem definition does not necessarily have to execute in a solution

Scheduling Alternative Activities

National Conference on Artificial Intelligence, pp.680-687, (1999)

引用59|浏览27
EI
下载 PDF 全文
引用
微博一下

摘要

In realistic scheduling problems, there may be choices among resources or among process plans. We formulate a constraint-based representation of alternative activities to model problems containing such choices. We extend existing constraint-directed scheduling heuristic commitment tech- niques and propagators to reason directly about the ...更多

代码

数据

简介
  • Scheduling problems addressed in the constraint-directed scheduling literature typically have a static activity definition: each activity must be scheduled on its specified resource(s).
  • It is common, in real-world scheduling problems to have a wider space of choices.
  • For it is sufficient to understand that they represent alternative paths in the activity network and, in a final solution, only one of the alternative paths can be present.
  • Part of the scheduling problem, is to decide if A2, A3, and A4 will execute, or if A6 and A7 will execute
重点内容
  • Scheduling problems addressed in the constraint-directed scheduling literature typically have a static activity definition: each activity must be scheduled on its specified resource(s)
  • Because the CBA propagator cannot be used when one or both members of an activity pair have a probability of existence value of less than 1 (Beck, 1999), the CBASlackPEX heuristic calculates the biased-slack on such activity pairs even if their time windows do not overlap
  • We introduced the probability of existence (PEX) of an activity and used it to represent that an activity in the original problem definition does not necessarily have to execute in a solution
  • Experimental results indicate that incorporating probability of existence values into the texture-based heuristics results in significantly higher quality commitments and better overall search performance
  • Performance differences are especially large when there is a wide range of probability of existence values in a problem
  • A key contribution of this work is the applicability of our representation of alternative activities to a wide variety of real-world scheduling problems
结果
  • PEX values into the texture-based heuristics results in significantly higher quality commitments and better overall search performance.
  • Performance differences are especially large when there is a wide range of PEX values in a problem.
  • Experimental results validate the use of PEX-edgefinding which, in most cases, leads to significantly better overall search performance.
  • The authors have introduced a mechanism to explicitly reason about choosing not to take certain actions in order to achieve an overall goal
  • Such reasoning has relevance in many areas of artificial intelligence.
结论
  • The experiments present interesting and conflicting results. While SumHeightPEX outperforms CBASlackPEX with PEX-edge-finding, their relative performance without PEXedge-finding is inconsistent: little difference is observed in Experiment 1, while, in Experiment 2, SumHeightPEX is significantly better.
  • Recall that in the original CBASlack heuristic, the most critical activity pair is one that is not already sequenced and that has the smallest biased-slack.
  • Because the CBA propagator cannot be used when one or both members of an activity pair have a PEX value of less than 1 (Beck, 1999), the CBASlackPEX heuristic calculates the biased-slack on such activity pairs even if their time windows do not overlap.
  • Heuristic commitment techniques and two edge-finding propagators were extended to account for PEX values
表格
  • Table1: PEX Values for a Subset of the Nodes in Figure 2
  • Table2: The Six Algorithms Used in the Experiments
  • Table3: The Characteristics of the Problems in Experiment 1
  • Table4: The Distribution of Alternative Resources for the Problems in Experiment 2
Download tables as Excel
基金
  • It was funded in part by the Natural Sciences Engineering and Research Council, IRIS Research Network, Manufacturing Research Corporation of Ontario, Baan Limited, and Digital Equipment of Canada. Thanks to Andrew Davenport and Angela Glover for discussion of and comments on previous versions of this paper
引用论文
  • Baptiste, P. and Le Pape, C. (1995). Disjunctive constraints for manufacturing scheduling: Principles and extensions. In Proceedings of the Third International Conference on Computer Integrated Manufacturing.
    Google ScholarLocate open access versionFindings
  • Baptiste, P. and Le Pape, C. (1996). Edge-finding constraint propagation algorithms for disjunctive and cumulative scheduling. In Proceedings of the 15th Workshop of the UK Planning and Scheduling Special Interest Group. Available from http://www.hds.utc.fr/baptiste/.
    Locate open access versionFindings
  • Beck, J. C. (1999). Texture measurements as a basis for heuristic commitment techniques in constraint-directed scheduling. PhD thesis, University of Toronto. Forthcoming.
    Google ScholarFindings
  • Beck, J. C., Davenport, A. J., Sitarski, E. M., and Fox, M. S. (1997a). Beyond contention: extending texture-based scheduling heuristics. In Proceedings of AAAI-97. AAAI Press, Menlo Park, California.
    Google ScholarLocate open access versionFindings
  • Beck, J. C., Davenport, A. J., Sitarski, E. M., and Fox, M. S. (1997b). Texture-based heuristics for scheduling revisited. In Proceedings of AAAI-97. AAAI Press, Menlo Park, California.
    Google ScholarLocate open access versionFindings
  • Carnegie Group Inc. (1994). Knowledge-based logistics planning system. Internal Documentation.
    Google ScholarFindings
  • Cheng, C. C. and Smith, S. F. (1997). Applying constraint satisfaction techniques to job shop scheduling. Annals of Operations Research, Special Volume on Scheduling: Theory and Practice, 70:327–378. Forthcoming.
    Google ScholarLocate open access versionFindings
  • Cohen, P. R. (1995). Empirical Methods for Artificial Intelligence. The MIT Press, Cambridge, Mass.
    Google ScholarFindings
  • Davenport, A. J., Beck, J. C., and Fox, M. S. (1999). An investigation into two approaches for resource allocation and scheduling. Technical report, Enterprise Integration Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto.
    Google ScholarFindings
  • Fox, M. (1986). Observations on the role of constraints in problem solving. In Proceedings of the Sixth Canadian Conference on Artificial Intelligence.
    Google ScholarLocate open access versionFindings
  • Fox, M. S. (1983). Constraint-Directed Search: A Case Study of Job-Shop Scheduling. PhD thesis, Carnegie Mellon University, Intelligent Systems Laboratory, The Robotics Institute, Pittsburgh, PA. CMU-RI-TR-85-7.
    Google ScholarFindings
  • Kott, A. and Saks, V. (1998). A multi-decompositional approach to integration of planning and scheduling – an applied perspective. In Proceedings of the Workshop on Integrating Planning, Scheduling and Execution in Dynamic and Uncertain Environments, Pittsburgh, USA.
    Google ScholarLocate open access versionFindings
  • Le Pape, C. (1994). Using a constraint-based scheduling library to solve a specific scheduling problem. In Proceedings of the AAAISIGMAN Workshop on Artificial Intelligence Approaches to Modelling and Scheduling Manufacturing Processes.
    Google ScholarLocate open access versionFindings
  • Nuijten, W. P. M. (1994). Time and resource constrained scheduling: a constraint satisfaction approach. PhD thesis, Department of Mathematics and Computing Science, Eindhoven University of Technology.
    Google ScholarFindings
  • Saks, V., Johnson, I., and Fox, M. (1993). Distribution planning: A constrained heuristic search approach. In Proceedings of the Knowledge-based System and Robotics Workshop, pages 13–19. Industry Canada.
    Google ScholarLocate open access versionFindings
  • Smith, S. F. and Cheng, C. C. (1993). Slack-based heuristics for constraint satisfaction scheduling. In Proceedings AAAI-93, pages 139–144.
    Google ScholarLocate open access versionFindings
0
您的评分 :

暂无评分

标签
评论
数据免责声明
页面数据均来自互联网公开来源、合作出版商和通过AI技术自动分析结果,我们不对页面数据的有效性、准确性、正确性、可靠性、完整性和及时性做出任何承诺和保证。若有疑问,可以通过电子邮件方式联系我们:report@aminer.cn