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Time dependent decision-making;dynamic priorities in the AHP/ANP: Generalizing from points to functions and from real to complex variables

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MATHEMATICAL AND COMPUTER MODELLING 2007年第7-8期46卷 860-891页

作者： Saaty, Thomas L. Univ Pittsburgh Pittsburgh PA 15260 USA

Because good decisions depend on the conditions of the future, and because conditions vary over time, to make a good decision requires judgments of what is more likely or more preferred over different time periods. There are at least three ways to deal with dynamic decisions. One is to include in the structure itself different factors that indicate change in time such as scenarios and different time periods and then carry out paired comparisons with respect to the time periods using the fundamental scale of the AHP. The second is to do paired comparisons as rates of relative change with respect to time. This is done at different points of time as representatives of intervals to which they belong. These intervals can have different lengths. For each representative point one needs to provide a pairwise judgment about the relative rate of change of one alternative over another and derive mathematical functions for that matrix of comparisons for one of the time periods. The third is to do what I proposed in my first book on the AHP and that is to use functions for the paired comparisons and derive functions from them. It is usually difficult to know what functions to use and what they mean. Ideas and examples are presented towards the development of a theory for dynamic decision making. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： dynamic priorities time dependent AHP AHP ANP priority functions time horizons neural firing

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PERFORMANCE OF THE PRIORITIZED RANDOM TOKEN PROTOCOL FOR HIGH-SPEED AND RADIO NETWORKS

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IEEE TRANSACTIONS ON COMMUNICATIONS 1993年第6期41卷 917-931页

作者： PARK, DS UN, CK KOREA ADV INST SCI & TECHNOL DEPT ELECT ENGNCOMMUN RES LABSEOUL 131SOUTH KOREA

In this paper, we present a random token protocol that incorporates priority functions. In this prioritized random token protocol, the access right to a channel is given to the user of the highest priority by giving the earliest scheduling time. The protocol is suitable for high-speed networks with frequent reconfiguration, and also for mobile networks. It can be used with and without the collision detection feature. We analyze the prioritized random token protocol with two priority classes and get the delay-throughput characteristics for each priority class. We show that the proposed protocol yields better throughput-delay performance than the p-persistent protocol of prioritized carrier sense multiple access. In addition, we discuss numerical results obtained for various system parameters and verify them by simulation.

关键词： .carrier sense collision detection highest priority priority classes Radio Networks high-speed networks Random Token priority functions earliest scheduling

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Procedures for providing robust gate assignments for arriving aircrafts

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2000年第1期120卷 63-80页

作者： Bolat, A King Saud Univ Dept Mech Engn Riyadh 11421 Saudi Arabia

Assigning commercial service aircrafts to the available gates at an airport depends on flights scheduled, their actual behavior relative to those schedules, aircraft servicing requirements and capacities of ramp facilities. Flight delays, severe weather, or equipment failures can disrupt the planned schedules, and compound the difficulty of maintaining smooth station operations. A mixed-binary mathematical model with a quadratic function for minimizing the variance of idle times at the gates is proposed to make the initial assignments insensitive to variations in flight schedules. Experimental results with a branch and bound algorithm indicate that more computational effort is required to assign flights optimally over low utilized gates. Furthermore, a heuristic employing the priority function which considers additionally the possible idle times from the future assignments outperforms the others, significantly. Over the real data obtained from the Saudi Arabian Airlines, average 87.4% and 76.2% of improvements can be obtained on the number of aircrafts assigned initially to remote area and that towed from their assigned gates during the real-time implementation, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： gate assignment branch and bound variance of idle times priority functions

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REAL-TIME PILOTING OF FLEXIBLE MANUFACTURING SYSTEMS

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 1994年第2期78卷 252-261页

作者： TAWEGOUM, R CASTELAIN, E GENTINA, JC ECOLE CENT LILLE LAB AUTOMAT & INFORMAT IND LILLECNRSURA D1440BP 48F-59651 VILLENEUVE DASCQFRANCE

In this Paper we introduce management functions in real time monitoring of FMS. We consider FMS in which the control unit is modeled using objects Petri nets. In these systems, machine round-ups connected by complex carriage systems, particular resources behaviour and disruption appearance generate considerable data flow. The flexibility of the system is expressed at the control level by indetermisms, creating resources access conflicts and encouraging parallelism of operations. Particular resources behaviour and disruption appearance create dynamic stickings, which need real time resolution methods. We aim for autonomous decisions of the hierarchical level yielding for the minimisation of reffective delays introduced by perturbations. We propose a hierarchical level divided into three parts: a planification level, a schedule level and a real time piloting level which we will detail in this paper. As the shop floor is steadily perturbated, the piloting level must use both, flexibility of machines and transport system to minimize part traveling duration. We present some fast methods able to absorb real time perturbations occuring during production, and to optimize resources management. The major difficulty is the estimation of the consequences induced by correcting actions. Thus, we look for a satisfying solution as a compromise between schedule propositions and current shop state.

关键词： ONLINE PRODUCTION CONTROL PERTURBATIONS DECISION-MAKING SCHEDULING RULES priority functions

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Meta optimization: Improving compiler heuristics with machine learning 03

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Conference on Programming Language Design and Implementation

作者： Stephenson, M Amarasinghe, S Martin, M O'Reilly, UM MIT Comp Sci Lab Cambridge MA 02139 USA MIT Artificial Intelligence Lab Cambridge MA 02139 USA

ISBN: (纸本)9781581136623

Compiler writers have crafted many heuristics over the years to approximately solve NP-hard problems efficiently. Finding a heuristic that performs well on a broad range of applications is a tedious and difficult process. This paper introduces Meta Optimization, a methodology for automatically fine-tuning compiler heuristics. Meta Optimization uses machine-learning techniques to automatically search the space of compiler heuristics. Our techniques reduce compiler design complexity by relieving compiler writers of the tedium of heuristic tuning. Our machine-learning system uses an evolutionary algorithm to automatically find effective compiler heuristics. We present promising experimental results. In one mode of operation Meta Optimization creates application-specific heuristics which often result in impressive speedups. For hyperblock formation, one optimization we present in this paper, we obtain an average speedup of 23% (up to 73%) for the applications in our suite. Furthermore, by evolving a compiler's heuristic over several benchmarks, we can create effective, general-purpose heuristics. The best general-purpose heuristic our system found for hyperblock formation improved performance by an average of 25% on our training set, and 9% on a completely unrelated test set. We demonstrate the efficacy of our techniques - on three different optimizations in this paper: hyperblock formation, register allocation, and data prefetching.

关键词： machine learning priority functions genetic programming compiler heuristics

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Improving Resource Allocation in MOEA/D with Decision-Space Diversity Metrics 8th

Improving Resource Allocation in MOEA/D with Decision-Space ...

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8th International Conference on the Theory and Practice of Natural Computing (TPNC)

作者： Lavinas, Yuri Aranha, Claus Ladeira, Marcelo Univ Tsukuba Tsukuba Ibaraki Japan Univ Brasilia Brasilia DF Brazil

ISBN: (纸本)9783030345006;9783030344993

One of the main algorithms for solving Multi-Objective Optimization Problems is the Multi-Objective Evolutionary Algorithm Based on Decomposition (MOEA/D). It is characterized by decomposing the multiple objectives into a large number of single-objective subproblems, and then solving these subproblems in parallel. Usually, these subproblems are considered equivalent, but there are works that indicate that some subproblems can be more difficult than others, and that spending more computational resources in these subproblems can improve the performance of MOEA/D. One open question about this strategy of "Resource Allocation" is: what should be the criteria for allocating more computational effort on one problem or another? In this work we investigate this question. We study four different ways to prioritize subproblems: Randomly, Relative Improvement, Diversity in Decision Space (proposed in this work), and inverted Diversity in Decision Space (also proposed in this work). We compare the performance of MOEA/D using these four different "priority functions" on the DTLZ and UF benchmarks. We evaluate the resulting IGD, proportion of non-dominated solutions, and visually analyse the resulting resource allocation and Pareto Front. The result of our experiments is that the priority function using diversity in decision space improved the MOEA/D, achieving better IGD values and higher proportion of non-dominated solutions.

关键词： Multi-Objective Optimization Resource Allocation priority functions

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Using Diversity as a priority Function for Resource Allocation on MOEA/D 19

Using Diversity as a Priority Function for Resource Allocati...

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Genetic and Evolutionary Computation Conference (GECCO)

作者： Lavinas, Yuri Aranha, Claus Sakurai, Testuya Univ Tsukuba Tsukuba Ibaraki Japan

ISBN: (纸本)9781450367486

The key characteristic of the Multi-Objective Evolutionary Algorithm Based on Decomposition (MOEA/D) is that a multi-objective problem is decomposed into multiple single-objective subproblems. In standard MOEA/D, all subproblems receive the same computational effort. However, as each subproblem relates to different areas of the objective space, it is expected that some subproblems are more difficult than others. Resource Allocation techniques allocates computational effort proportional to each subproblem's difficulty. This difficulty is estimated by a priority function. Using Resource Allocation, MOEA/D could spend less effort on easier subproblems and more on harder ones, improving efficiency. We propose that using diversity as the priority criteria results in better allocation of computational effort. Therefore we propose a new priority function: decision space diversity. We compare the proposed diversity based priority with previous approaches on the OF benchmarks. The proposed decision space priority achieved high IGD values, excellent rate of non-dominated solutions on the benchmark problem.

关键词： Resource Allocation Diversity assessment Multiobjective Optimization priority functions

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The Application of Petri Nets to Modelling Historical Processes

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IFAC Proceedings Volumes 1999年第2期32卷 6320-6325页

作者： M.A. Hersh Centre of Systems and Control and Department of Electronics and Electrical Engineering University of Glasgow Glasgow Gl2 8LT Scotland UK Tel: +44 141 330 4906. Fax: +44 141 330 6004

A new methodology for the representation of historical processes based on Petri nets is presented. The use of priority functions is required to ensure that transitions (events) occur in the correct order and weights on input and output arcs may be required to ensure that they occur once only. A number of modifications are made to the standard Petri net to facilitate the representation of processes. This approach is particularly appropriate for investigating causal links between events and possible or likely futures. The methodology is illustrated by its application to modelling an example from Scottish history.

关键词： Petri nets historical processes modelling causality priority functions weighting

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