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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/6

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Now showing 1 - 5 of 5
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    PublicationOpen Access
    How (not) to integrate blood subtyping technology to kidney exchange
    (Elsevier, 2018) Department of Economics; Yılmaz, Özgür; Sönmez, Tayfun; Ünver, Utku; Faculty Member; Faculty Member; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638; N/A; N/A
    Even though kidney exchange became an important source of kidney transplants over the last decade with the introduction of market design techniques to organ transplantation, the shortage of kidneys for transplantation is greater than ever. Due to biological disadvantages, patient populations of blood types B/O are disproportionately hurt by this increasing shortage. The disadvantaged blood types are overrepresented among minorities in the US. In order to mitigate the disproportionate harm to these biologically disadvantaged groups, the UNOS reformed in 2014 the US deceased-donor kidney-allocation system, utilizing a technological advance in blood typing. The improved technology allows a certain fraction of blood type A kidneys, referred to as subtype A2 kidneys, to be transplanted to medically qualified patients of blood types B/O. The recent reform prioritizes subtype A2 deceased-donor kidneys for blood type B patients only. When restricted to the deceased-donor allocation system, this is merely a distributional reform with no adverse impact on the overall welfare of the patient population. In this paper we show that the current implementation of the reform has an unintended consequence, and it de facto extends the preferential allocation to kidney exchange as well. Ironically this "spillover" not only reduces the number of living-donor transplants for the overall patient population, but also for the biologically disadvantaged groups who are the intended beneficiaries of the reform. We show that minor variations of the current policy do not suffer from this unintended consequence, and we make two easy-to-implement, welfare-increasing policy recommendations.
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    PublicationOpen Access
    Regenerator location problem in flexible optical networks
    (Informs, 2017) Karasan, Oya Ekin; Department of Industrial Engineering; Yıldız, Barış; Faculty Member; Department of Industrial Engineering; College of Engineering; 258791
    In this study, we introduce the regenerator location problem in flexible optical networks. With a given traffic demand, the regenerator location problem in flexible optical networks considers the regenerator location, routing, bandwidth allocation, and modulation selection problems jointly to satisfy data transfer demands with the minimum cost regenerator deployment. We propose a novel branch-and-price algorithm for this challenging problem. Using real-world network topologies, we conduct extensive numerical experiments to both test the performance of the proposed solution methodology and evaluate the practical benefits of flexible optical networks. In particular, our results show that, making routing, bandwidth allocation, modulation selection, and regenerator placement decisions in a joint manner, it is possible to obtain drastic capacity enhancements when only a very modest portion of the nodes is endowed with the signal regeneration capability.
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    PublicationOpen Access
    Transmission of risk preferences from mothers to daughters
    (Elsevier, 2017) Alan, Şule; Boneva, Teodora; Crossley, Thomas F.; Department of Psychology; Department of Economics; Baydar, Nazlı; Ertaç, Seda; Faculty Member; Faculty Member; Department of Psychology; Department of Economics; Graduate School of Social Sciences and Humanities; College of Administrative Sciences and Economics; 50769; 107102
    We study the transmission of risk attitudes in a unique survey of mothers and children in which both participated in an incentivized risk preference elicitation task. We document that risk preferences are correlated between mothers and children when the children are just 7-8 years old. This correlation is only present for daughters. We further show that a measure of maternal involvement is a strong moderator of the association between mothers' and daughters' risk tolerance. This is consistent with a role for socialization and parental investment in the intergenerational transmission of risk preferences.
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    PublicationOpen Access
    Strategic effects of renegotiation-proof contracts
    (De Gruyter, 2012) Gerratana, Emanuele; Department of Economics; Koçkesen, Levent; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 37861
    It is well known that non-renegotiable contracts with third parties may have an effect on the outcome of a strategic interaction and thus serve as a commitment device. We address this issue when contracts are renegotiable. More precisely, we analyze the equilibrium outcomes of two-stage games with renegotiation-proof third-party contracts in relation to the equilibrium outcomes of the same game without contracts. We assume that one of the parties in the contractual relationship is unable to observe everything that happens in the game when played by the other party. We first show that when contracts are non-renegotiable, the set of equilibrium outcomes of the game with contracts is restricted to a subset of Nash equilibrium outcomes of the original game. Introducing renegotiation, in general, imposes further constraints and in some games implies that only subgame perfect equilibrium outcomes of the original game can be supported. However, there is a large class of games in which non-subgame perfect equilibrium outcomes can also be supported, and hence, third-party contracts still have strategic implications even when they are renegotiable.
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    PublicationOpen Access
    Logistics planning of cash transfer to Syrian refugees in Turkey
    (Elsevier, 2022) Kian, Ramez; Erdoğan, Güneş; de Leeuw, Sander; Sabet, Ehsan; Kara, Bahar Y.; Demir, Muhittin H.; Department of Industrial Engineering; Salman, Fatma Sibel; Faculty Member; Department of Industrial Engineering; College of Engineering; 178838
    This paper addresses a humanitarian logistics problem connected with the Syrian refugee crisis. The ongoing conflict in Syria has caused displacement of millions of people. Cash-based interventions play an important role in aiding people in the post-crisis period to enhance their well-being in the medium and longer term. The paper presents a study on how to design a network of administrative facilities to support the roll-out of cash-based interventions. The resulting multi-level network consists of a central registration facility, local temporary facilities, mobile facilities and vehicles for door-to-door visits. The goal is to reach the maximum number of eligible beneficiaries within a specified time period while minimizing logistics costs, subject to a limit on total security risk exposure. A mixed integer programming model is formulated to optimize the inter-related facility location and routing decisions under multiple objectives. The authors develop a hierarchical multi-objective metaheuristic algorithm to obtain efficient solutions. An application of the model and the solution algorithm to real data from a region in the southeast of Turkey is presented, with associated managerial insights.