Browsing by Author "Koksalan, Murat"

Now showing 1 - 7 of 7

Citation - WoS: 74
Citation - Scopus: 82
An Exact Algorithm for Finding Extreme Supported Nondominated Points of Multiobjective Mixed Integer Programs
(Informs, 2010) Özpeynirci, Özgür; Koksalan, Murat
In this paper, we present an exact algorithm to find all extreme supported nondominated points of multiobjective mixed integer programs. The algorithm uses a composite linear objective function and finds all the desired points in a finite number of steps by changing the weights of the objective functions in a systematic way. We develop further variations of the algorithm to improve its computational performance and demonstrate our algorithm's performance on multiobjective assignment, knapsack, and traveling salesperson problems with three and four objectives.
Citation - WoS: 22
Citation - Scopus: 28
A Flexible Approach To Ranking With an Application To Mba Programs
(Elsevier Science Bv, 2010) Koksalan, Murat; Buyukbasaran, Tayyar; Özpeynirci, Özgür; Wallenius, Jyrki
We develop a model for flexibly ranking multi-dimensional alternatives/units into preference classes via Mixed Integer Programming. We consider a linear aggregation model, but allow the criterion weights to vary within pre-specified ranges. This allows the individual alternatives/units to play to their strengths. We illustrate the use of the model by considering the Financial Times Global MBA Program rankings and discuss the implications. We argue that in many applications neither the data nor the weights or the aggregation model itself is precise enough to warrant a complete ranking. providing an argument for sorting or what we call flexible ranking. (C) 2009 Elsevier B.V. All rights reserved.
Citation - WoS: 14
Citation - Scopus: 17
An Interactive Probabilistic Approach To Multi-Criteria Sorting
(Taylor & Francis Inc, 2013) Bugdaci, Asli Gul; Koksalan, Murat; Özpeynirci, Selin; Serin, Yasemin
This article addresses the problem of sorting alternatives evaluated by multiple criteria among preference-ordered classes. An interactive probabilistic sorting approach is developed in which the probability of an alternative being in each class is calculated and alternatives are assigned to classes keeping the probability of incorrect assignments below a specified small threshold value. The decision maker is occasionally required to place alternatives to classes. The probabilities for unassigned alternatives are updated in light of the new information and the procedure is repeated until all alternatives are classified. This is the first sorting approach reported in the literature to use an explicit probability of classifying alternatives that is consistent with the underlying preference structure of the decision maker. The proposed approach is demonstrated in a problem concerning the sorting MBA programs.
Citation - WoS: 12
Multi-Criteria Sorting With Category Size Restrictions
(World Scientific Publ Co Pte Ltd, 2017) Koksalan, Murat; Mousseau, Vincent; Özpeynirci, Selin
We consider the multi-criteria sorting problem where alternatives that are evaluated on multiple criteria are assigned into ordered categories. We focus on the sorting problem with category size restrictions, where the decision maker (DM) may have some concerns or constraints on the number of alternatives that should be assigned to some of the categories. We develop an approach based on the UTADIS method that fits an additive utility function to represent the decision maker's preferences. We introduce additional variables and constraints to enforce the restrictions on the sizes of categories. The new formulation reduces the number of binary variables and hence decreases the computational effort compared to the existing approaches in the literature. We further improve the computational efficiency by developing lower and upper bounds on the rank of each alternative in order to narrow down the set of categories that each alternative can be assigned to. We demonstrate our approach on two applications from practice.
Citation - WoS: 7
Citation - Scopus: 9
Multiobjective Traveling Salesperson Problem on Halin Graphs
(Elsevier, 2009) Özpeynirci, Özgür; Koksalan, Murat
In this paper, we study traveling salesperson (TSP) and bottleneck traveling salesperson (BTSP) problems on special graphs called Halin graphs. Although both problems are NP-Hard on general graphs, they are polynomially solvable on Halin graphs. We address the multiobjective versions of these problems. We show computational complexities of finding a single nondominated point as well as finding all nondominated points for different objective function combinations. We develop algorithms for the polynomially solvable combinations. (C) 2008 Elsevier B.V. All rights reserved.
Citation - WoS: 33
Citation - Scopus: 40
A New Outranking-Based Approach for Assigning Alternatives To Ordered Classes
(John Wiley & Sons Inc, 2009) Koksalan, Murat; Mousseau, Vincent; Özpeynirci, Özgür; Özpeynirci, Selin
We consider the problem of assigning alternatives evaluated on several criteria into ordered categories C(1), C(2), ..., C(p). This problem is known as the multi-criteria sorting problem and arises in many situations such as classifying countries into different risk levels based on economical and socio-political criteria, evaluating credit applications of bank customers. We are interested in sorting methods that are grounded on the construction Of Outranking relations. Among these, the Electre Tri method requires defining multidimensional profiles that represent the frontier separating consecutive categories C(h) and C(h+1). and assigns an alternative to categories according to how it compares to each of the profiles. The explicit specification of the profiles of consecutive categories can be difficult for decision makers. We develop a new Outranking based sorting method that does not require the explicit definition of profiles. We instead require the decision maker to assign a Subset of reference alternatives to the categories. To assign the remaining alternatives. each such alternative is compared to reference alternatives, and assigned to categories accordingly. (C) 2008 Wiley Periodicals, Inc. Naval Research Logistics 56: 74-85, 2009
Citation - WoS: 7
Pyramidal Tours and Multiple Objectives
(Springer, 2010) Özpeynirci, Özgür; Koksalan, Murat
In this study, we work on the traveling salesperson problems and bottleneck traveling salesperson problems that have special matrix structures and lead to polynomially solvable cases. We extend the problems to multiple objectives and investigate the properties of the nondominated points. We develop a pseudo-polynomial time algorithm to find a nondominated point for any number of objectives. Finally, we propose an approach to generate all nondominated points for the biobjective case.