Browsing Department of Informatics by Title
Now showing items 413432 of 649

Optimal preparation of graph states
(Peer reviewed; Journal article, 20110412)We show how to prepare any graph state of up to 12 qubits with: (a) the minimum number of controlledZ gates, and (b) the minimum preparation depth. We assume only onequbit and controlledZ gates. The method exploits the ... 
Optimal ternary cyclic codes with minimum distance four and five
(Journal article, 201411)Cyclic codes are an important subclass of linear codes and have wide applications in data storage systems, communication systems and consumer electronics. In this paper, two families of optimal ternary cyclic codes are ... 
Optimization issues in medical imaging and fibertracking
(Doctoral thesis, 20080227)Fiber tracking is a relatively recent methodology, made possible by access to new highly advanced MR scanners able to produce highquality diffusion tensor images (DTI), which promises clinicians a possibility to observe ... 
Optimization Models for Turbine Location in Wind Farms
(Master thesis, 20120524)The topic of this thesis is wind farm optimization. The goal is to be able to decide where to install wind turbines within a given region in order to maximize the power output in two different scenarios: For a fixed number ... 
Optimization of reliable cyclic cable layouts in offshore wind farms
(Peer reviewed; Journal article, 2020)A novel approach for optimizing reliable cable layouts in offshore wind farms is presented. While optimization models traditionally are designed to suggest acyclic cable routes, those developed in this work recognize that ... 
Optimization Problems in Communication Networks and MultiAgent Path Finding
(Doctoral thesis, 20190913)This dissertation is a compilation of six research papers that are focused on three dif ferent topics summarized in the text. The first three papers address NPhard problems arising in adhoc wireless com munication ... 
Optimizing Approximate Weighted Matching on Nvidia Kepler K40
(Conference object; Peer reviewed, 2018)Matching is a fundamental graph problem with numerous applications in science and engineering. While algorithms for computing optimal matchings are difficult to parallelize, approximation algorithms on the other hand ... 
OuroborosE: An efficient Latticebased KeyExchange Protocol
(Peer reviewed; Journal article, 2018)The Bit Flipping algorithm is a hard decision decoding algorithm originally designed by Gallager in 1962 to decode Low Density Parity Check Codes (LDPC). It has recently proved to be much more versatile, for Moderate Parity ... 
OutputSensitive Filtering of Streaming Volume Data
(Peer reviewed; Journal article, 201602)Realtime volume data acquisition poses substantial challenges for the traditional visualization pipeline where data enhancement is typically seen as a preprocessing step. In the case of 4D ultrasound data, for instance, ... 
Packing arcdisjoint cycles in tournaments
(Journal article; Peer reviewed, 2019)A tournament is a directed graph in which there is a single arc between every pair of distinct vertices. Given a tournament T on n vertices, we explore the classical and parameterized complexity of the problems of determining ... 
Packing cycles faster than ErdosPosa
(Journal article; Peer reviewed, 2019)The Cycle Packing problem asks whether a given undirected graph $G=(V,E)$ contains $k$ vertexdisjoint cycles. Since the publication of the classic ErdösPósa theorem in 1965, this problem received significant attention ... 
Parallel algorithms for computing kconnectivity
(Master thesis, 20170505) 
Parallel algorithms for matching under preference
(Master thesis, 20170620) 
Parallel Graph Algorithms for Combinatorial Scientific Computing
(Doctoral thesis, 20110826) 
Parallel Matching and Clustering Algorithms on GPUs
(Doctoral thesis, 20170617) 
Parameter optimisation for the improved modelling of industrialscale gas explosions
(Doctoral thesis, 20190617)This thesis presents work on improving the predictive capabilities of a numerical model by parameter optimisation. The numerical model is based on computational fluid dynamics (CFD) and predicts the consequences of ... 
Parameterization Above a Multiplicative Guarantee
(Journal article; Peer reviewed, 2020)Parameterization above a guarantee is a successful paradigm in Parameterized Complexity. To the best of our knowledge, all fixedparameter tractable problems in this paradigm share an additive form defined as follows. Given ... 
Parameterized complexity classification of deletion to list matrixpartition for loworder matrices
(Journal article; Peer reviewed, 2019)Given a symmetric l x l matrix M=(m_{i,j}) with entries in {0,1,*}, a graph G and a function L : V(G)  > 2^{[l]} (where [l] = {1,2,...,l}), a list Mpartition of G with respect to L is a partition of V(G) into l parts, ... 
Parameterized complexity of conflictfree matchings and paths
(Journal article; Peer reviewed, 2019)An input to a conflictfree variant of a classical problem Gamma, called ConflictFree Gamma, consists of an instance I of Gamma coupled with a graph H, called the conflict graph. A solution to ConflictFree Gamma in (I,H) ... 
Parameterized Complexity of Directed Spanner Problems
(Journal article; Peer reviewed, 2020)We initiate the parameterized complexity study of minimum tspanner problems on directed graphs. For a positive integer t, a multiplicative tspanner of a (directed) graph G is a spanning subgraph H such that the distance ...