Ανάθεση αντικειμένων και εξωτερικές επιδράσεις σε γράφους

Kasouridis, Stylianos

dc.contributor.author	Kasouridis, Stylianos	en
dc.date.accessioned	2022-01-10T11:41:45Z
dc.date.available	2022-01-10T11:41:45Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/54292
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.21990
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-sa/3.0/gr/	*
dc.subject	Theory of algorithms	en
dc.subject	Optimization	en
dc.subject	Graph theory	en
dc.subject	Approximation algorithms	en
dc.subject	Externalities	en
dc.subject	Θεωρία αλγορίθμων	el
dc.subject	Βελτιστοποίηση	el
dc.subject	Θεωρία γραφημάτων	el
dc.subject	Προσεγγιστικοί αλγόριθμοι	el
dc.subject	Εξωτερικές επιδράσεις	el
dc.title	Ανάθεση αντικειμένων και εξωτερικές επιδράσεις σε γράφους	el
dc.title	Object allocation and positive graph externalities	en
dc.accessRights	Κασουρίδης, Στυλιανός	el
heal.type	bachelorThesis
heal.classification	Theory of algorithms	en
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2021-07-09
heal.abstract	We consider the influence of heterogeneous objects placed in various locations in a network to neighboring objects or entities. We introduce and study a model where elements with high value exert a positive externality on neighboring elements whose value is lower. We aim at maximizing this positive influence called graph externality. We first prove the NP-hardness of the problem, when the maximum degree is 3, by exploiting a connection to the minimum dominating set problem. We then proceed to show that the problem is polynomial time solvable when the maximum degree is 2. We also present efficient exact and approximation algorithms for several special cases and topologies. In particular, we show that if only two valuations exist, then a natural greedy strategy, which works well for maximum coverage problems, leads to a constant approximation algorithm. We conduct extensive numerical experiments that show that the greedy algorithm performs very well for general valuations. We further consider generalizations of the problem to other externality models and evaluate the greedy approach under these more general settings.	en
heal.advisorName	Pagourtzis, Aris	en
heal.committeeMemberName	Pagourtzis, Aris	en
heal.committeeMemberName	Fotakis, Dimitris	en
heal.committeeMemberName	Symvonis, Antonios
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών. Τομέας Τεχνολογίας Πληροφορικής και Υπολογιστών	el
heal.academicPublisherID	ntua
heal.numberOfPages	90 σ.	el
heal.fullTextAvailability	false