Online voluntary mentoring: Optimising the assignment of students and mentors

After the closure of the schools in Hungary from March 2020 due to the pandemic, many students were left at home with no or not enough parental help for studying, and in the meantime some people had more free time and willingness to help others in need during the lockdown. In this paper we describe the optimisation aspects of a joint NGO project for allocating voluntary mentors to students using a web-based coordination mechanism. The goal of the project has been to form optimal pairs and study groups by taking into the preferences and the constraints of the participants. In this paper we present the optimisation concept, and the integer programming techniques used for solving the allocation problems. Furthermore, we conducted computation simulations on real and generated data for evaluate the performance of this dynamic matching scheme under different parameter settings

Online voluntary mentoring: Optimising the assignment of students and mentors

After the closure of the schools in Hungary from March 2020 due to the pandemic, many students were left at home with no or not enough parental help for studying, and in the meantime some people had more free time and willingness to help others in need during the lockdown. In this paper we describe the optimisation aspects of a joint NGO project for allocating voluntary mentors to students using a webbased coordination mechanism. The goal of the project has been to form optimal pairs and study groups by taking into account the preferences and the constraints of the participants. In this paper, we present the optimisation concept and the integer programming techniques used for solving the allocation problems. Furthermore, we conducted computational simulations on real and generated data to evaluate the performance of this dynamic matching scheme under different parameter settings

Hálózati feladatok megoldása lineáris programozási feladatok segítségével

Ezen jegyzetet elektronikus jegyzetnek szánjuk. A lineáris programozási feladatok CPLEX LP kódját sok feladat esetében megadjuk. Ezek a kódok változtatás nélkül futtathatóak, megkönnyítve az eredmények reprodukálását. Ez a módszer a tanulást megkönnyíti, viszont a jegyzet méretét megnöveli. Ezért nyomatékosan kérjük Önöket, hogy ne nyomtassák ki ezt a jegyzetet, használják elektronikus változatban. Kérjük, óvja környezetét! Ne nyomtassa ki ezt a jegyzetet

Átsorolási szabályok optimalizálása bónusz-málusz rendszerekben

Bónusz-málusz rendszerek kockázatkezelési módszerek, amelyek leggyakoribb előfordulása a kötelező gépjármű-felelősségbiztosítás esetén figyelhető meg. Bónusz-málusz rendszerek kalibrációja jellemzően abban merül ki, hogy egy adott átsorolási szabályt feltételezve optimális díjakat határoznak meg. A cikkben bemutatunk egy vegyes egészértékű LP modellt, amely során a díjakat és az átsorolási szabályokat egyszerre tudjuk optimalizálni. A modellel ezeken túlmenően a BM kategóriák optimális számát is meghatározhatjuk

IP solutions for international kidney exchange programmes

In kidney exchange programmes patients with end-stage renal failure may exchange their willing, but incompatible living donors among each other. National kidney exchange programmes are in operation in ten European countries, and some of them have already conducted international exchanges through regulated collaborations. The exchanges are selected by conducting regular matching runs (typically every three months) according to well-defined constraints and optimisation criteria, which may differ across countries. In this work we give integer programming formulations for solving international kidney exchange problems, where the optimisation goals and constraints may be different in the participating countries and various feasibility criteria may apply for the international cycles and chains. We also conduct simulations showing the long-run effects of international collaborations for different pools and under various national restrictions and objectives.Comment: Journal version submitted to CEJOR journal (VOCAL special issue) of the paper with the same name accepted at the proceedings of VOCAL Optimization Conference 201

IP Solutions for International Kidney Exchange Programmes

In kidney exchange programmes patients with end-stage renal failure may exchange their willing, but incompatible living donors among each other. National kidney exchange programmes are in operation in ten European countries, and some of them have already conducted international exchanges through regulated collaborations. The exchanges are selected by conducting regular matching runs (typically every three months) according to well-defined constraints and optimisation criteria, which may differ across countries. In this work we give integer programming formulations for solving international kidney exchange problems, where the optimisation goals and constraints may be different in the participating countries and various feasibility criteria may apply for the international cycles and chains. We also conduct simulations showing the long-run effects of international collaborations for different pools and under various national restrictions and objectives. We compute the expected gains of the cooperation between two countries with different pool sizes and different restrictions on the cycle-length. For instance, if country A allows 3-way cycles and country B allows 2-way cycles only, whilst the pool size of country A is four times larger than the pool size of country B (which is a realistic case for the relation of Spain and France, respectively), then the increase in the number of transplants will be about 2% for country A and about 37% for country B

Optimization of Bonus-Malus Systems [védés előtt]

Bonus-Malus System (BMS) is a risk managing method mostly used in liability insurances. The most general application of the BMS is in the Motor third-party liability insurance. In a BMS, there are finitely many classes, each having a different premium. At the start of the contract, each policyholder is assigned to the "initial class". Subsequently, suppose the policyholder has a claim in the following period. In that case, he/she moves to a worse class, so the policyholder's payment may increase in the subsequent period. If he/she does not have a claim in a particular period, then he/she moves to a better class; therefore, his/her payment may become less in the following period. The classification rule – how many classes the policyholder will move up or down in the system – is called the transition rule. Hence, a transition rule specifies where the policyholder will be reclassified in the subsequent period for each possible claim. Our contribution to the literature of the optimization of the BMS can be summarized as: • We investigate a model that was introduced by Heras et al. (2004) but with a modified objective function. We proved that an optimal premium-scale always exists with this objective function in which all premiums equal one of the risk groups expected claim. • We considered the same model with a profit constraint. In this case, we proved that an optimal premium-scale always exists in which there is only one type of premium that is unequal to any risk group's expected claim. • We introduced a MILP model for the optimization of transition rules with fixed premiums. We considered unified and non-unified transition rules optimization. In the case of unified transition rules, we gave the rule to exclude those transition rules that would lead to a non-irreducible Markov chain. • We introduced a MILP model for the joint optimization of transition rules and premiums. We can determine the exact solution with the investigated objective function when we do not consider the profit constraint. However, we can only approximate it otherwise. • We introduced an extended version of the model, where instead of the stationary probabilities, we use multi-period optimization. • We introduced modeling approaches to consider the BMS premium with other statistical estimations in the final premium. Finally, we compared the methods with numerical experiments on realistic data. • We introduced an optimization model for a BMS where the classification depends on the claim amount

Towards Multi-Level Territorial Governance in Hungary

This thesis sets out to develop credible scenarios outlining the future territorial governance system of Hungary. The overview on the challenges of the Hungarian spatial development pointed to a direction of the lacking overarching administrative background concept. The EU discourse on territorial policies, spearheaded by the Territorial Agenda 2020 has become more and more influenced by the contemporary organizational concepts of public administration. With associating two notable conceptions, the Multi-level Governance and the Territorial Governance, the author has created a spectacle, under which the main characteristics of the dominant European spatial planning models (namely the Nordic-, the Anglo-Saxon- and the French variants) have become comparable. The main features of the models have been organized into matrices along three major aspects of inquiry: The quality of governance, multi-level relations and multi-level structure. These matrices served as a reliable framework for the scenario-writing process, which outlined four possible paths for the territorial administrative system of Hungary