SSRN Author: Frits SpieksmaFrits Spieksma SSRN Content
http://www.ssrn.com/author=524669
http://www.ssrn.com/rss/en-usSat, 10 Mar 2018 01:55:59 GMTeditor@ssrn.com (Editor)Sat, 10 Mar 2018 01:55:59 GMTwebmaster@ssrn.com (WebMaster)SSRN RSS Generator 1.0New: Robust Balanced OptimizationAn instance of a balanced optimization problem with vector costs consists of a ground set X, a cost vector for every element of X, and a system of feasible subsets over X. The goal is to find a feasible subset that minimizes the so-called imbalance of values in every coordinate of the underlying vector costs. Balanced optimization problems with vector costs are equivalent to the robust optimization version of balanced optimization problems under the min-max criterion. We regard these problems as a family of optimization problems; one particular member of this family is the known balanced assignment problem. We investigate the complexity and approximability of robust balanced optimization problems in a fairly general setting. We identify a large family of problems that admit a 2-approximation in polynomial time, and we show that for many problems in this family this approximation factor 2 is best-possible (unless P=NP). We pay special attention to the balanced assignment problem with ...
http://www.ssrn.com/abstract=3134369
http://www.ssrn.com/1674579.htmlFri, 09 Mar 2018 11:47:56 GMTNew: The Transportation Problem with ConflictsThe transportation problem is a fundamental problem in Operations Research, where items need to be transported from supply nodes (each with a given supply) to demand nodes (each with a given demand) in the cheapest possible way. Here, we are interested in a generalization of the transportation problem where, each supply node has a (possibly empty) set of conflicting pairs of demand nodes, and each demand node a (possibly empty) set of conflicting pairs of supply nodes. Each supply node may only receive supply from at most one demand node of each conflicting pair. Likewise, each demand node may only send supply to at most one supply node of each conflicting pair. We call the resulting problem the transportation problem with conflicts (TPC). We show that the complexity of TPC depends upon the structure of the so-called conflict graph that follows from the conflicting pairs. More concrete, we show that for many graph-classes the corresponding TPC remains NP-hard, and for some special ...
http://www.ssrn.com/abstract=3082778
http://www.ssrn.com/1650108.htmlSat, 09 Dec 2017 05:31:08 GMTNew: Conference Scheduling — A Personalized ApproachScientific conferences have become an essential part of academic research and require significant investments (e.g. time and money) from their participants. It falls upon the organizers to develop a schedule that allows the participants to attend the talks of their interest. We present a combined approach of assigning talks to rooms and time slots, grouping talks into sessions, and deciding on an optimal itinerary for each participant. Our goal is to maximize attendance, taking into account the common practice of session hopping. On a secondary level, we accommodate presenters’ availabilities. We use a hierarchical optimization approach, sequentially solving integer programming models, which has been applied to construct the schedule of the MathSport (2013), MAPSP (2015) and ORBEL (2017) conferences.
http://www.ssrn.com/abstract=2937631
http://www.ssrn.com/1575795.htmlTue, 21 Mar 2017 10:26:26 GMT