Now showing items 413-432 of 649

    • Optimal preparation of graph states 

      Cabello, Adán; Danielsen, Lars Eirik; López-Tarrida, Antonio J.; Portillo, José R. (Peer reviewed; Journal article, 2011-04-12)
      We show how to prepare any graph state of up to 12 qubits with: (a) the minimum number of controlled-Z gates, and (b) the minimum preparation depth. We assume only one-qubit and controlled-Z gates. The method exploits the ...
    • Optimal ternary cyclic codes with minimum distance four and five 

      Li, Nian; Li, Chunlei; Helleseth, Tor; Ding, Cunsheng; Tang, Xiaohu (Journal article, 2014-11)
      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 fiber-tracking 

      Bergmann, Ørjan (Doctoral thesis, 2008-02-27)
      Fiber tracking is a relatively recent methodology, made possible by access to new highly advanced MR scanners able to produce high-quality diffusion tensor images (DTI), which promises clinicians a possibility to observe ...
    • Optimization Models for Turbine Location in Wind Farms 

      Haugland, Jan Kristian (Master thesis, 2012-05-24)
      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 

      Klein, Arne; Haugland, Dag (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 Multi-Agent Path Finding 

      Ivanova, Marika (Doctoral thesis, 2019-09-13)
      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 NP-hard problems arising in ad-hoc wireless com- munication ...
    • Optimizing Approximate Weighted Matching on Nvidia Kepler K40 

      Naim, Md.; Manne, Fredrik; Halappanavar, Mahantesh; Tumeo, Antonino; Langguth, Johannes (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 ...
    • Ouroboros-E: An efficient Lattice-based Key-Exchange Protocol 

      Deneuville, Jean-Christophe; Gaborit, Philippe; Guo, Qian; Johansson, Thomas (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 ...
    • Output-Sensitive Filtering of Streaming Volume Data 

      Šoltészová, Veronika; Birkeland, Åsmund; Stoppel, Sergej; Viola, Ivan; Bruckner, Stefan (Peer reviewed; Journal article, 2016-02)
      Real-time volume data acquisition poses substantial challenges for the traditional visualization pipeline where data enhancement is typically seen as a pre-processing step. In the case of 4D ultrasound data, for instance, ...
    • Packing arc-disjoint cycles in tournaments 

      Bessy, Stephane; Bougeret, Marin; Krithika, R; Sahu, Abhishek; Saurabh, Saket; Thiebaut, Jocelyn; Zehavi, Meirav (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 Erdos-Posa 

      Lokshtanov, Daniel; Mouawad, Amer E.; Saurabh, Saket; Zehavi, Meirav (Journal article; Peer reviewed, 2019)
      The Cycle Packing problem asks whether a given undirected graph $G=(V,E)$ contains $k$ vertex-disjoint cycles. Since the publication of the classic Erdös--Pósa theorem in 1965, this problem received significant attention ...
    • Parallel algorithms for computing k-connectivity 

      Haakonsen, Joachim (Master thesis, 2017-05-05)
    • Parallel algorithms for matching under preference 

      Lerring, Håkon Heggernes (Master thesis, 2017-06-20)
    • Parallel Graph Algorithms for Combinatorial Scientific Computing 

      Patwary, Mostofa Ali (Doctoral thesis, 2011-08-26)
    • Parallel Matching and Clustering Algorithms on GPUs 

      Naim, Md. (Doctoral thesis, 2017-06-17)
    • Parameter optimisation for the improved modelling of industrial-scale gas explosions 

      Both, Anna-Lena (Doctoral thesis, 2019-06-17)
      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 

      Fomin, Fedor; Golovach, Petr; Lokshtanov, Daniel; Panolan, Fahad; Saurabh, Saket; Zehavi, Meirav (Journal article; Peer reviewed, 2020)
      Parameterization above a guarantee is a successful paradigm in Parameterized Complexity. To the best of our knowledge, all fixed-parameter tractable problems in this paradigm share an additive form defined as follows. Given ...
    • Parameterized complexity classification of deletion to list matrix-partition for low-order matrices 

      Agrawal, Akanksha; Kolay, Sudeshna; Madathil, Jayakrishnan; Saurabh, Saket (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 M-partition of G with respect to L is a partition of V(G) into l parts, ...
    • Parameterized complexity of conflict-free matchings and paths 

      Agrawal, Akanksha; Jain, Pallavi; Kanesh, Lawqueen; Saurabh, Saket (Journal article; Peer reviewed, 2019)
      An input to a conflict-free variant of a classical problem Gamma, called Conflict-Free Gamma, consists of an instance I of Gamma coupled with a graph H, called the conflict graph. A solution to Conflict-Free Gamma in (I,H) ...
    • Parameterized Complexity of Directed Spanner Problems 

      Fomin, Fedor; Golovach, Petr; Lochet, William; Misra, Pranabendu; Saurabh, Saket; Sharma, Roohani (Journal article; Peer reviewed, 2020)
      We initiate the parameterized complexity study of minimum t-spanner problems on directed graphs. For a positive integer t, a multiplicative t-spanner of a (directed) graph G is a spanning subgraph H such that the distance ...