Scientific conferences are an essential part of academic research. It falls upon the organizers to develop a schedule that allows the participants to attend the presentations of their interest. We present a combined approach of assigning presentations to rooms and time slots, grouping presentations 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 MAPSP2015 conference.

Scientific 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.

The proverb 'the longest mile is the last mile home' quite accurately describes my feelings at the end of this PhD journey. As usual at the end of your PhD, there is one thing left to do to complete the doctoral dissertation: writing the only part of this behemoth that people might actually readthe acknowledgements. Acknowledgements are usually quite non-consequential, in the sense that people are rarely evaluated on them (unlike, hopefully, the rest of this work), yet they do matter. Amidst the celebration, the right people require thanks in the right way. As is tradition, the first paragraph is dedicated to the advisor. Fun fact; while writing these acknowledgements, and going over how some of my predecessors handled it before me, I noticed that it is even tradition to mention that it is tradition to mention the advisor first. Fortunately, I had the privilege of having not just one, but two advisors. I would like to express my sincere gratitude to my advisors Prof. Dr. Frits Spieksma and Prof. Dr. Dries Goossens for the continuous support of my PhD study and related research, for their patience, motivation, and immense knowledge. Their door was-usually-open whenever I ran into a spot of trouble or had a question. Their guidance and attention to detail helped me bring iii v Van der Auweraer (check out the Nerf Super Soaker Zombie Strike Revenge Contaminator), Silvia Valeria Padilla Tinoco (pura vida!), and Sebastian 'speedy' Gonzalez, Finally, the newcomers: Heletje Van Staden, Laurens Deprez, and Kim De Boeck. It falls on you to keep the cake traditions alive! Phew, I really hope I did not forget anyone in that list.. . A lifelong friend obviously deserves mentioning. Tommy Graindourze, I like to think your philosophical ways kept me sane(r) during my PhD journey. The computer and board game distractions probably also helped. Finally, this last paragraph is dedicated to family. Special thanks go to my sister, her husband and their lovely daughter, my (first) godchild. I also want to express my deep gratitude to my parents. Both have instilled many admirable qualities in me, and have given me a solid foundation in life. They provided me with unfailing love, support and continuous encouragement throughout my years of study and the process of researching and writing this thesis. This accomplishment would not have been possible without them. The clichéd 'words cannot express' is fitting. Still, I will try: mom and dad, I profoundly thank you.

We consider auctions of items that can be arranged in rows. Examples of such a setting appear in allocating pieces of land for real estate development, or seats in a theater or stadium. The objective is, given bids on subsets of items, to find a subset of bids that maximizes auction revenue (often referred to as the winner determination problem). We describe a dynamic programming algorithm which, for a k-row problem with connected and gap-free bids, solves the winner determination problem in polynomial time. We study the complexity for bids in a grid, complementing known results in literature. Additionally, we study variants of the geometrical winner determination setting. We provide a NP-hardness proof for the 2-row setting with gap-free bids. Finally, we extend this dynamic programming algorithm to solve the case where bidders submit connected, but not necessarily gap-free bids in a 2-row and a 3-row problem.