Models and heuristics for hard routing and knapsack problems

One of the world’s biggest challenges is that living beings have to share a limited amount of resources. As people of science, we strive to find innovative ways to better use these resources, to reach and positively affect more and more people. In the field of optimization, we aim at finding an optimal allocation of limited sets of resources to...

Coding Techniques for Noisy Channels with Gain and/or Offset Mismatch

Data transmission is ubiquitous in all walks of life, ranging from basic home and office appliances like compact disc players and hard disk drives to deep space communication. More often than not, the communication and storage channels are noisy, and data might be distorted during transmission. However, noise is not the only disturbance during...

On Phylogenetic Encodings and Orchard Networks

Phylogenetic networks are a type of graph with vertices and edges, used to elucidate the evolutionary history of species. The fundamental goal of phylogenetic research is to infer the true phylogeny of species from raw data such as DNA sequences and morphological data. Most network inference methods require one to solve an NP-hard problem;...

Rearranging Phylogenetic Networks

Optimization in the Photolithography Bay: Scheduling and the Traveling Salesman Problem

In a semiconductor factory, integrated circuits (or chips) are constructed on top of slabs of silicon, called wafers. The construction of these wafers is complicated and many different processing steps are needed to gradually building the chip layer by layer. Of these steps, photolithography uses the most expensive equipment. Therefore, the...

Logistics of emergency response vehicles: Facility location, routing, and shift scheduling

This thesis discusses different aspects of the logistics of emergency response vehicles. In most parts, we consider providers of ambulance care in the Netherlands. However, also firefighters and air ambulance providers in both Canada and Norway are considered. Even though significant differences exist between the considered systems, they share...

Moment methods in extremal geometry

In this thesis we develop techniques for solving problems in extremal geometry. We give an infinite dimensional generalization of moment techniques from polynomial optimization. We use this to construct semidefinite programming hierarchies for approximating optimal packing densities and ground state energies of particle systems. For this we...

The Eigenvalue Method for Extremal Problems on Infinite Vertex-Transitive Graphs

This thesis is about maximum independent set and chromatic number problems on certain kinds of infinite graphs. A typical example comes from the Witsenhausen problem: For $n \geq 2$, let $S^{n-1} := \{ x \in \R^n : \|x\|_2 =1 \}$ be the unit sphere in $\R^n$, and let $G=(V,E)$ be the graph with $V = S^{n-1}$, in which two points in $S^{n-1}$ are...

The Shortest Path Problem on Real Road Networks: Theory, Algorithms and Computations

This thesis contains the following subjects: - Several shortest path algorithms, both label-setting and label-correcting; - Unidirectional and bidirectional methods; - A* algorithms; - Symmetric and balanced estimators; - Preprocessing techniques. This thesis contains an elaborate, comparative evaluation of the various methods described....

On Lattice Methods in Integer Optimization

Integer optimization is a powerful modeling tool both for problems of practical and more abstract origin. Since the 1970s we have seen huge progress in the size of problem instances that can be tackled. This progress is mostly due to the many results in polyhedral combinatorics and to algorithms and implementations related to the polyhedral...