Landmarks in Planning: Using landmarks as Intermediary Golas or as a Pseudo-Heuristic

Algorithmic planners occasionally waste effort and thus computing time trying to solve certain tasks, as they often lack the human ability to recognize essential paths. These essential paths, termed landmarks, are vital for optimizing planning processes. This study revisits landmark-based planning methods introduced by Richter, Helmert, and...

Heuristics for a facility location problem with a quadratic objective function

Facility location problems are an important set of problems within the field of optimisation. These problems consider which facilities to open out of a set of possible facilities and how to assign users to the open facilities. Most of the facility location problems studied have a linear objective. In this thesis, we consider a facility location...

Augmenting VSIDS heuristic for the RCPSP/t by initializing activity values using domain-specific information

The Variable State Independent Decaying Sum (VSIDS) heuristic is one of the most effective variable selection heuristics for Conflict-Driven Clause-Learning (CDCL) SAT solvers. It works by keeping track of the activity values for each variable, which get bumped and decayed based on conflict analysis. These activity values usually start out...

Optimizing district heating networks: Exploring the solution space: Transporting geothermal energy to consumers in Delft

Society is facing a huge challenge in switching the energy sectors dependence on fossil fuels into an energy sector using mostly renewable energy sources. The switch towards using more sustainable energy sources is known as the energy transition. The goal of the energy transition is to lower the greenhouse gas (GHG) emissions emitted by the...

SAT-based optimisation for the resource-constrained project scheduling problem with time-dependent resource capacities and requests

In this paper, a variant of the resource-constrained project scheduling problem is discussed. This variant introduces time-dependence for resource capacities and requests, making the problem a more realistic model for many practical applications such as production scheduling and medical research project planning. The main aim of this paper is to...

Exploring Heuristic Methods for the Resource-Constrained Project Scheduling Problem with Logical Constraints

This paper presents the use of a heuristic solution method to improve the process of creating a conjunctive normal form (CNF) encoding of and finding optimal solutions to instances of the resource-constrained project scheduling problem with logical constraints (RCPSP-Log).<br/><br/>The RCPSP is an optimisation problem consisting of a set of...

Multi-Actor Portfolio Analysis Methodology: A Stochastic and Heuristic based approach to deal with information scarce environments

Previous academic work on Portfolio Decision Analysis (PDA) have pointed at the advantage of using PDA in multi-actor situations and environmental sectors, but have also pointed at the lack of research done in such case studies. Currently there exist situations where PDA would be beneficial but current methods are not able to analyse the systems...

Offline-Online Reoptimization using a Hybrid Method

Realistic vehicle routing problems have been highly relevant for years in a wide variety of domains. One such domain is food delivery, where well-crafted routes can reduce costs and contribute to customer satisfaction. This thesis formulates a problem variant for the restaurant meal delivery problem in order to examine the reoptimization of meal...

New cycle-based formulation, cost function, and heuristics for DC OPF based controlled islanding

This paper presents a new formulation for intentional controlled islanding (ICI) of power transmission grids based on mixed-integer linear programming (MILP) DC optimal power flow (OPF) model. We highlight several deficiencies of the most well-known formulation for this problem and propose new enhancements for their improvement. In particular...

Choice-driven service network design for an integrated fixed line and demand responsive mobility system

Sparsely populated areas tend to be poorly served by Fixed Line and Schedule (FLS) public transport systems as the operation of a regular bus line is not economically viable for such areas. Therefore, introducing a Demand Responsive Transport (DRT) to partially replace FLS can result in increasing mobility service accessibility and inclusion....

Heuristic Methods for Minimum-Cost Pipeline Network Design: A Node Valency Transfer Metaheuristic

Designing low-cost network layouts is an essential step in planning linked infrastructure. For the case of capacitated trees, such as oil or gas pipeline networks, the cost is usually a function of both pipeline diameter (i.e. ability to carry flow or transferred capacity) and pipeline length. Even for the case of incompressible, steady flow,...

A combined forecasting and packing model to optimize decision-making under uncertainty in transportation logistics: an application to air cargo revenue management

Cargo airlines' Revenue Management (RM) departments oversee the acceptance/rejection process of incoming bookings. The overarching goal is to accept as many bookings as possible, hence maximizing profit, while avoiding overbooking and offloading of already accepted shipments, to ensure customer satisfaction. This whole process is characterized...

Cellular automata based S-boxes

Cellular Automata (CA) represent an interesting approach to design Substitution<br/>Boxes (S-boxes) having good cryptographic properties and low implementation costs. From the cryptographic perspective, up to now there have been only ad-hoc studies about specific kinds of CA, the best known example being the χ nonlinear transformation used in...

Solution methods for the tray optimization problem

In order to perform medical surgeries, hospitals keep large inventories of surgical instruments. These instruments need to be sterilized before each surgery. Typically the instruments are kept in trays. Multiple trays may be required for a single surgery, while a single tray may contain instruments that are required for multiple surgical...