Browsing by Subject "Multi-criteria optimization"

Now showing 1 - 3 of 3

Open Access
Ensuring multidimensional fairness in public service
(2020-12) Akoluk, Damla
In this study, we focus on service planning problems, in which decisions lead to distributions of multiple benefits to multiple users, hence involve fairness and efficiency concerns in a multidimensional way. We develop two mathematical modeling-based approaches that incorporate these concerns in such problems. The first formulation aggregates the multidimensional efficiency concerns and multidimensional fairness concerns in a bi-objective model. The second formulation defines an objective function for each benefit, which maximizes the total social welfare obtained from that specific benefit distribution, hence results in an nobjective model, where n is the number of benefits. We illustrate and compare these approaches on an example public service provision problem.
Open Access
On multi-criteria chance-constrained capacitated single-source discrete facility location problems
(Elsevier, 2019) Kınay, Ö. B.; Saldanha-da-Gama, F.; Kara, Bahar Y.
This work aims at investigating multi-criteria modeling frameworks for discrete stochastic facility location problems with single sourcing. We assume that demand is stochastic and also that a service level is imposed. This situation is modeled using a set of probabilistic constraints. We also consider a minimum throughput at the facilities to justify opening them. We investigate two paradigms in terms of multi-criteria optimization: vectorial optimization and goal programming. Additionally, we discuss the joint use of objective functions that are relevant in the context of some humanitarian logistics problems. We apply the general modeling frameworks proposed to the so-called stochastic shelter site location problem. This is a problem emerging in the context of preventive disaster management. We test the models proposed using two real benchmark data sets. The results show that considering uncertainty and multiple objectives in the type of facility location problems investigated leads to solutions that may better support decision making.
Open Access
Orphan drug logistics
(2020-07) Dursunoğlu, Çağla Fatma
"Orphan drugs" are medical products that are developed to treat orphan diseases. Since they are required by a small number of population, the pharmaceutical industry is not interested much in them. Hence they are produced in small amounts and they are difficult to attain. Moreover, patients may need them urgently. There are regulations for the transportation of orphan drugs to the patient. Those regulations differ among the countries. In this thesis, we focus on the logistics of the orphan drugs motivated by the application in Turkey. We analyze the implementation dynamics of Turkey and define related Operational Research (OR) problems. The overall problem can be considered as an application of locationrouting problem. We identify four performance measures based on urgency and ambulance scarcity. The primal aim in the current system is to serve the patient in need at short notice. Therefore, the minimization of the total distance is chosen to be the first performance measure. However, due to scarcity of ambulances in each city, the total extra disturbance, the maximum extra disturbance and the total number of cities disturbed are also analyzed. The problem includes multi-criteria optimization and the -constraint method is used to analyze the Pareto-optimal solutions. Turkey case is considered for computational analysis.