Ozgur Ozpeynirci

Izmir University of Economics · Department of Logistics Management

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 vari...

Pharmacy Duty Scheduling (PDS) is the activity of assigning pharmacies to days during a planning horizon with the purpose of serving society outside regular working hours. In Turkey, pharmacies are retailers that operate during the working hours in weekdays. However, demand for medicine at nights, at the weekends and on holidays must be satisfied b...

Multiple criteria sorting problem is to assign objects evaluated with multiple criteria to one of the predefined ordered classes. In this study, we consider the inverse multiple criteria sorting problem (IMCSP), in which it is possible to perform actions which have an impact of objects evaluations, hence on the objects classification. IMCSP aims at...

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...

This study addresses the operational fixed job scheduling problem under spread time constraints. The problem is to select a subset of jobs having fixed ready times and deadlines for processing on identical parallel machines such that total weight of the selected jobs is maximised. We first give a mathematical formulation of the problem and then ref...

Multiple criteria sorting problem aims to assign objects evaluated on multiple criteria to ordered classes. In inverse multiple criteria sorting problem, the class assignments of objects are known and the decision maker can manipulate the scores of objects on criteria by implementing actions. Selected actions enable the improvement of objects’ fina...

Energy security and environmental concerns resulting from fossil fuel consumption have led to important changes in the U.S. energy policy in the past two decades. One of those is the Renewable Fuel Standard that mandates blending biofuels, especially cellulosic biofuels, with conventional transportation fuels. This requires producing substantial am...

We consider a resource allocation problem in which the decision maker is responsible for selecting a group of projects to generate a portfolio, with the aim of maximizing the total benefit, and distributing the budget in a balanced way across different categories. We assume that the decision maker defines an interval for the desired share of each c...

This chapter seeks to identify the set of conditions under which the mirroring hypothesis holds, proposing that modular product architecture leads to organizational modularity (i.e., supplier disintegration). The contradictory results on the mirroring hypothesis in the extant literature call for a more holistic analysis of the issue. To this end, t...

We consider a resource allocation problem where a decision maker (DM) is to distribute a certain budget among alternative projects in order to create the best portfolio. The DM aims to generate a portfolio with (1) a high return and (2) a balanced distribution of resources among categories. We assume that the DM has a quasiconcave value function an...

Logistics Performance Index (LPI), published by the World Bank, is a powerful tool for countries to benchmark and assess their performance in global logistics business. Researchers have investigated relations between LPI scores and other related statistics for developing country logistics policies; however, no studies examine the strategies of coun...

Multiple criteria sorting is the problem of assigning objects that are evaluated on multiple criteria to ordered classes. In inverse multiple criteria sorting problem, the assignment of objects to classes is known. The decision maker (DM) can implement actions to improve the scores of objects on criteria, thus enabling the assignment of objects to...

Although the research on forest fires and fire-fighting in different regions is continuously expanding, cooperation opportunities on fire-fighting between different countries still remains unexplored. This study aims to evaluate the international cooperation opportunities on airborne forest fire-fighting by concentrating on cooperation between Turk...

In this study, we consider the multiple criteria constrained sorting problem and propose an interactive algorithm. The problem is to assign alternatives evaluated on multiple criteria to sorted categories where categories may have size restrictions. The proposed interactive algorithm determines the eligible categories for each alternative and the a...

The aim of this paper is to analyze and improve the freight transportation plan by considering multimodal transportation with maritime, road, and railway transportation. We develop a bi-objective mathematical model, of which objectives are total cost and number of handling operations, an indicator for operational difficulty. The model decides on th...

In this study, we consider the nadir points of multiobjective integer programming problems. We introduce new properties that restrict the possible locations of the nondominated points necessary for computing the nadir points. Based on these properties, we reduce the search space and propose an exact algorithm for finding the nadir point of multiobj...

In this study, we develop an interactive algorithm for the multiple criteria selection problem that aims to find the most preferred alternative among a set of known alternatives evaluated on multiple criteria. We assume the decision maker (DM) has a quasi-concave value function that represents his/her preferences. The interactive algorithm selects...

Günümüzde, taşımacılığın çevresel etkileri sıklıkla tartışılmakta ve karbon salınımı daha düşük olan taşıma şekillerine yönelim giderek artmaktadır. Bu taşıma türlerinde, nihai alıcıya teslimatın genellikle karayolu ile yapılması çoklu taşıma ağlarının kullanımını arttırmıştır. Bu çalışmada bir petrokimya şirketinin gerçek hayat probleminden yola...

In this study, we define the pharmacy duty scheduling problem, which requires a subset of pharmacies to be on duty on national holidays, at weekends and at nights, in order to be able to satisfy the emergency medicine needs. We model the pharmacy duty scheduling problem as a multi-period p-median problem with special side constraints, and analyze t...

In this study, we work on the order picking problem (OPP) in a specially designed warehouse with a single picker. Ratliff and Rosenthal (1983) show that the special design of the warehouse and use of one picker lead to a polynomially solvable case. We address the multiobjective version of this special case and investigate the properties of the nond...

More than 100 participants from Australia, Austria, Belgium, Canada, Chile, China, Czech Republic, Finland, France, Germany, Hungary, Israel, Italy, Netherlands, Poland, Qatar, Russian Federation, Spain, Turkey, United Kingdom, and USA got together at ECCO XXVII – CO 2014 (http://www.ecco2014.ma.tum.de/). The scientific program included more than...

Abstract In this paper, we study on the Pharmacy Duty Scheduling (PDS) problem, where a subset of pharmacies should be on duty on national holidays, at weekends and at nights in order to be able to satisfy the emergency drug needs of the society. PDS problem is a multi-period p-median problem with special side constraints and it is an NP-Hard probl...

We consider the problem of ranking alternatives evaluated on several criteria. This problem may arise in many real life applications like ranking countries, cities, projects, universities, academic programs and students. A number of methods have been proposed for this problem. ELECTRE, one of the widely used ranking methods, uses outranking relatio...

More than 100 participants from Australia, Austria, Belgium, Canada, Chile, China, Czech Republic, Finland, France, Germany, Hungary, Israel, Italy, Netherlands, Poland, Qatar, Russian Federation, Spain, Turkey, United Kingdom, and USA got together for ECCO XXVII – CO 2014 (http://www.ecco2014. ma.tum.de/) from May 1 to 3, 2014 at the Garching Camp...

In this paper, we present a mathematical model that finds the optimal multimodal freight transportation plan for manufacturing companies during a planning horizon. The model considers road and sea transportation options. The sea transportation requires chartering at least one ship among candidate ships. The chartered ships operate on several predef...

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 nondo...

Problem Statement: The educational recourses available for postgraduate education are limited compared with the resources for undergraduate education. An academic advisor is required for each graduate student. The academic staff allocates an important portion of his/her time for graduate studies of his/her students. Since the number of academic sta...

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...

We consider the problem of assigning alternatives evaluated on several criteria into ordered categories C1,C2,…,Cp. 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 ban...

Systematic approach followed by The Scientific and Technical Research Council of Turkey (TUBITAK) for the evaluation/selection of the research project proposals grouped under three categories as (1) curiosity driven academic research, and (2) customer driven applied research, both in universities and research institutions, and (3) technological and...

Data Envelopment Analysis (DEA) is a methodology that computes efficiency values for decision making units (DMU) in a given period by comparing the outputs with the inputs. In many applications, inputs and outputs of DMUs are monitored over time. There might be a time lag between the consumption of inputs and the production of outputs. We develop a...

We proposed to restart Simulated Annealing (SA) algorithm with a temperature jump when termination is declared. This approach and basic SA are compared. Different parameter settings for SA are tested. Two performance criteria are collected for each parameter settings; percent deviation of resulting tour length from optimal solution and the running...

We proposed to restart Simulated Annealing (SA) algorithm with a temperature jump when termination is declared. This approach and basic SA are compared. Different parameter settings for SA are tested. Two performance criteria are collected for each parameter settings; percent deviation of resulting tour length from optimal solution and the running...