جستجوی مقالات مرتبط با کلیدواژه « heuristic method » در نشریات گروه « علوم انسانی »

In this paper a new two-phase method is presented for solving the curriculum based university course timetabling problem. In both phases of the new present method a new metaheuristic approach is used.

Methodology:

 In the first phase of the new method, a feasible high quality solution is computed. To this end, at first the hard constraints relating to the time periods are considered and a solution is computed that satisfies these hard constraints. In the next step, a new method is introduced for the assignment of rooms to courses, after application of which on the solution that satisfies the time period hard constraints, a feasible solution is computed. In the second phase, at first several new neighborhood functions are used to improve the quality of computed feasible solution. While the fitness function of the first phase is based on the violation of hard constraints, the fitness function of the second phase is based on the penalty of the feasible solution.

The numerical results indicate that the required computing time increases with the size of instances and the algorithm tends to converge towards the optimal solution after a few minutes.

Originality/Value: 

The presented algorithm enables us to deal with large university course timetabling problems in practice. Moreover, it provides us with an efficient way to obtain feasible solutions to such real-world instances and try to improve their quality.

Natural disasters management requires local information in order to be ready against dangers and reduce their procedure. Hence، evaluation of landslide occurrence in the area which is prone to landslide due to geographical condition and human constructions is high crucial. Ghale Chai dam located at Ajabshir Watershed is one kind of such areas. So the aim of present investigation is to identify hillside instabilities and movements and their influencing factors to prevent their harmful effects on natural resources and other parts of economical and engineering development and recognize points with high prone of danger. Hence، the aim of present investigation is to assess analytical network process and Heuristic method in determining the landslide prone areas in range axis and reservoir of Ghale Chai dam of Ajabshir. Methods and Materials: The efficiency of network analysis process and logistic regression method were studied to investigate landslide potential in studied area dam. ANP model building requires the definition of elements and their assignment to clusters and a definition of their relationships (I. e. the connections between them indicating the flow of influence between the elements). Like AHP، ANP is founded on ratio scale measurements and pair wise comparisons of elements to divide priorities of selected alternatives. In addition relations among criteria and sub-criteria are included in evaluations، allowing dependencies both within a cluster (inner dependence) and between clusters (outer dependence) (Saaty: 2001). Pairwise comparison is now done، both for weighting clusters (criteria) and for estimating the direction and importance of influences between elements، numerically pictured as ratio scale in a so-called super matrix. Network analysis process was used for the first time in Iran in order to evaluate landslide، done using super decision and arc GIS software. However، to assess landslide susceptibility using heuristic method there are two common approaches: direct and indirect method. The first method applies direct assessment to interpret susceptibility in the field on the basis of detailed maps (geomorphological maps، for instance). The latter does not assess directly in the field، but via data integration techniques in any particular software. This study uses indirect heuristic method. Heuristic approach is a semi-qualitative method. Besides uses knowledge properties (expert opinions، previous research results or literature recommendations)، it also uses index-based procedures such as simple ranking and rating or analytical hierarchy process (AHP) in assigning weight and creating model. Concerning this، scoring and weighting process are crucial to build a model in heuristic approach.

Considering research questions، a three-layer network model composed of target layer، criteria layer and options layer was designed and organized in network analysis process. The priority of danger classes was determined based on their coefficients after doing paired comparisons among elements and clusters. Zoning map was classified in five classes from very high to very low. The weighting judgment process in pair-wise comparison gives a weight for every Influencing factor. From the calculation، the final criteria tree (with weight in 2 digits) was created. Bigger weights indicates that، the pertinent factor gives bigger influence toward the model. Aspect has the biggest contribution (0. 2519)، followed by distance to road and litology with value 0. 1786 and 0. 1747، respectively. On the other side، the lowest contribution is given by slope (0. 0387)، followed by Dem (0. 0590). No negative weights in heuristic method. The inconsistency value is 0، 0 62194: smaller than 0، 1. It means، according to SMCE validation، the choosing process is consistent. No improper stage while positioning the factor based on its importance to another After running paired comparisons between elements and clusters the priority of the danger classes based on their significance was determined and the coefficients of the factors showed that the aspect factor has the maximum effect in occurrence of the landslides if the area.

Decision making is inseparable from management and it is considered as base for decision making. Decision making has an important role in the strategic level. Thus, strategies, models and variety methods are established to help managers which decision making is one of them. There are different kinds of relations among the elements of decision making, particularly among criteria, for this purpose ANP method has proposed for involving all relations between elements of the problem. ANP method is somehow sophisticated and time consuming that makes us to use softwares to solve the problems even a simple problem that often is concerned to strategist that needs a rapid reaction and less patience. The reason that strategies in most cases prefer AHP more than ANP in strategic situation is simplicity of the ANP posses in achieving to result but AHP doesn’t consider the dependency of the criteria's which results to wasting opportunities and capital because of choosing inappropriate strategy. The meta-heuristic proposed method in this paper is named SIMANP that with it's simple mechanism, high accuracy, fast giving result, less time consuming and satiety to software solves the network problems accurate and easily. The SIMANP method will endow strategists and strategy managers who need accuracy, simple and fast giving result with the advantages of ANP Compared with AHP.