PRIMENA FAZI LOGIKE ZA REŠAVANJE NP-TEŠKIH PROBLEMA RUTIRANJA VOZILA I LOKACIJE RESURSA METODAMA RAČUNARSKE INTELIGENCIJE

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PRIMENA FAZI LOGIKE ZA REŠAVANJE NP-TEŠKIH PROBLEMA RUTIRANJA VOZILA I LOKACIJE RESURSA METODAMA RAČUNARSKE INTELIGENCIJE

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dc.contributor.advisor Marić, Miroslav
dc.contributor.author Radojčić, Nina
dc.date.accessioned 2018-12-03T14:34:37Z
dc.date.available 2018-12-03T14:34:37Z
dc.date.issued 2018
dc.identifier.uri http://hdl.handle.net/123456789/4737
dc.description.abstract In this dissertation, three NP-hard optimization problems are studied and va- rious computational intelligence methods are considered for solving them, with a special emphasis on the possibilities of applying fuzzy logic in order to improve the performances of proposed methods. In addition, it is shown how fuzzy logic can be incorporated into a model to make it more adequate to real world applications. The first problem considered is the Risk-Constrained Cash-in-Transit Vehicle Routing Problem (RCTVRP) that represents a special case of the vehicle routing problem (VRP). Similar to the classical VRP, the aim is to determine the collection routes from one depot to a number of customers in order to minimize the overall travel distance (or cost). Additionally, the safety aspect of the routed risk constraints are introduced in the case of RCTVRP. The RCTVRP concerns the issue of secu- rity during the transportation of cash or valuable goods (e.g. in the cash-in-transit industry). The other two problems studied in this dissertation belong to the class of loca- tion problems: the Load Balancing Problem (LOBA) and the Max-Min Diversity Problem (MMDP). The goal of the LOBA problem is to locate a fixed number of facilities, such that the difference between the maximum and minimum number of customers served by each facility is balanced. The LOBA model is useful in cases where customers naturally choose the closest facility. The MMDP consists of se- lecting a subset of a fixed number of elements from a given set in such a way that the diversity among the selected elements is maximized. This problem also arises in real world situations encompassing a variety of fields, particularly the social and biological sciences. In order to solve the RCTVRP, a fuzzy GRASP (Greedy Randomized Adaptive Search Procedure) is hybridized with Path Reliking (PR) methodology. Carefully adjusted fuzzy modification incorporated into the proposed GRASP for the RC- TVRP improved its performance. Moreover, in this dissertation a new PR structure is implemented and can be used for other vehicle routing problems. To improve the algorithm’s time complexity, a new data structure for the RCTVRP is incor- porated. The proposed fuzzy GRASP with PR hybrid shows better computational performance compared to its non-fuzzy version. Furthermore, computational results on publicly available data sets indicate that the proposed algorithm outperforms all existing methods from the literature for solving the RCTVRP. For solving the LOBA problem two efficient hybrid metaheuristic methods are proposed: a combination of reduced and standard variable neighborhood search met- hods (RVNS-VNS) and hybridization of evolutionary algorithm and VNS approach (EA-VNS). The proposed hybrid methods are first benchmarked and compared to all the other methods on existing test instances for the LOBA problem with up to 100 customers and potential suppliers. In order to test the effectiveness of the pro- posed methods, we modify several large-scale instances from the literature with up to 402 customers and potential suppliers. Exhaustive computational experiments show that the proposed hybrid methods quickly reach all known optimal solutions while providing solutions on large-scale problem instances in short CPU times. Re- garding solution quality and running times, we conclude that the proposed EA-VNS approach outperforms other considered methods for solving the LOBA problem. EA approach is also proposed for solving the MMDP. Computational experi- ments on a smaller benchmark data set showed that the classic EA quickly reached all optimal solutions obtained previously by an exact solver. However, some of the larger instances of MMDP were challenging for classic EA. Although researchers have established the most commonly used parameter setting for EA that has good performance for most of the problems, it is still challenging to choose the adequate values for the parameters of the algorithm. One approach to overcome this is chan- ging parameter values during the algorithm run. As part of this dissertation this problem was addressed by extending the evolutionary algorithm by adding a fuzzy rule formulated from EA experts’ knowledge and experience. The implemented fuzzy rule changes the mutation parameter during the algorithm run. The results on tested instances indicate that the proposed fuzzy approach is more suitable for solving the MMDP than classic EA. For all three problems addressed whereas the smaller instances that CPLEX was able to solve, obtained optimal solutions were used for comparison with proposed methods and all of the proposed methods obtained these optimal solutions. Moreover, in this dissertation it has been shown that fuzzy logic is a successful tool in modeling the RCTVRP. In this problem the risk constraints are set by using a risk threshold T on each route and thus, the routes with risk larger than T are forbidden. However, in this dissertation the aim is to take into account the probability of being robbed along each route instead of just allowing solutions with routes that satisfy the risk constraints. A new fuzzy model for the RCTVRP is developed which takes into account the value of the risk index of each route and the solutions with lower values of risk indexes on their routes are considered superior. In order to achieve that fuzzy numbers are used in the improved model. Moreover, two mixed integer program formulations of new fuzzy model are developed and presented in this dissertation. The introduced fuzzy model is compared with the model from the literature using an adequate example and the advantages of the newly proposed fuzzy RCTVRP is demonstrated. Computational experiments are performed and the comparison of the two models given in the paper show that the newly presented approach leads to safer routes. en_US
dc.description.provenance Submitted by Slavisha Milisavljevic (slavisha) on 2018-12-03T14:34:36Z No. of bitstreams: 1 tezaNinaRadojicic.pdf: 1665812 bytes, checksum: 79c28d46d246147ae9e9dc4f6d4f3d92 (MD5) en
dc.description.provenance Made available in DSpace on 2018-12-03T14:34:37Z (GMT). No. of bitstreams: 1 tezaNinaRadojicic.pdf: 1665812 bytes, checksum: 79c28d46d246147ae9e9dc4f6d4f3d92 (MD5) Previous issue date: 2018 en
dc.language.iso sr en_US
dc.publisher Beograd en_US
dc.title PRIMENA FAZI LOGIKE ZA REŠAVANJE NP-TEŠKIH PROBLEMA RUTIRANJA VOZILA I LOKACIJE RESURSA METODAMA RAČUNARSKE INTELIGENCIJE en_US
mf.author.birth-date 1987-10-25
mf.author.birth-place Čačak en_US
mf.author.birth-country Srbija en_US
mf.author.residence-state Srbija en_US
mf.author.citizenship Srpsko en_US
mf.author.nationality Srpsko en_US
mf.subject.area Computer Science en_US
mf.subject.keywords omputational intelligence, metaheuristics, fuzzy logic, NP-hard pro- blems, combinatorial optimization en_US
mf.subject.subarea Computational intelligence en_US
mf.contributor.committee Pavlović-Lažetić, Gordana
mf.contributor.committee Marić, Miroslav
mf.contributor.committee Marić, Filip
mf.contributor.committee Stanimirović, Zorica
mf.contributor.committee Takači, Aleksandar
mf.university.faculty Mathematics faculty en_US
mf.document.references 195 en_US
mf.document.pages 140 en_US
mf.document.location Beograd en_US
mf.document.genealogy-project No en_US
mf.university Belgrade en_US

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