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Minimum Fillin of Sparse Graphs: Kernelization and Approximation
(Dagstuhl Publishing, 2011)The Minimum Fillin problem is to decide if a graph can be triangulated by adding at most k edges. The problem has important applications in numerical algebra, in particular in sparse matrix computations. We develop ...Conference object 
Finding Induced Subgraphs via Minimal Triangulations
(Dagstuhl Publishing, 2010)Potential maximal cliques and minimal separators are combinatorial objects which were introduced and studied in the realm of minimal triangulation problems in cluding Minimum Fillin and Treewidth. We discover unexpected ...Conference object 
Approximating Acyclicity Parameters of Sparse Hypergraphs
(Dagstuhl Publishing, 2009)The notions of hypertree width and generalized hypertree width were introduced by Gottlob, Leone, and Scarcello (PODS'99, PODS'01) in order to extend the concept of hypergraph acyclicity. These notions were further generalized ...Conference object 
Kernel(s) for Problems with No Kernel: On OutTrees with Many Leaves
(Dagstuhl Publishing, 2009)The {\sc $k$Leaf OutBranching} problem is to find an outbranching, that is a rooted oriented spanning tree, with at least $k$ leaves in a given digraph. The problem has recently received much attention from the viewpoint ...Conference object 
Testing the presence of CP violation in the 2HDM
(PoS  Proceedings of Science, 20150427)We review CP properties of the TwoHiggsDoublet model. In particular, we show that sponta neous CP violation occurs in the parameter space on the border between regions allowing explicit CP violation and those where ...Conference object 
Subexponential Algorithms for Partial Cover Problems
(Dagstuhl Publishing, 2009)Partial Cover problems are optimization versions of fundamental and well studied problems like {\sc Vertex Cover} and {\sc Dominating Set}. Here one is interested in covering (or dominating) the maximum number of edges (or ...Conference object 
Impact of springtime HimalayanTibetan Plateau snowpack on the onset of the Indian summer monsoon in coupled seasonal forecasts
(Springer, 20160220)The springtime snowpack over the Himalayan–Tibetan Plateau (HTP) region and Eurasia has long been suggested to be an influential factor on the onset of the Indian summer monsoon. To assess the impact of realistic initialization ...Journal article 
Finding even subgraphs even faster
(Dagstuhl Publishing, 2015)Problems of the following kind have been the focus of much recent research in the realm of parameterized complexity: Given an input graph (digraph) on n vertices and a positive integer parameter k, find if there exist k ...Conference object 
Maximum matching width: New characterizations and a fast algorithm for dominating set
(Dagstuhl Publishing, 2015)We give alternative definitions for maximum matching width, e.g., a graph G has mmw(G) <= k if and only if it is a subgraph of a chordal graph H and for every maximal clique X of H there exists A,B,C \subseteq X with A ...Conference object 
Fast biclustering by dual parameterization
(Dagstuhl Publishing, 2015)We study two clustering problems, Starforest Editing, the problem of adding and deleting edges to obtain a disjoint union of stars, and the generalization Bicluster Editing. We show that, in addition to being NPhard, none ...Conference object 
Parameterized complexity of secluded connectivity problems
(Dagstuhl Publishing, 2015)The Secluded Path problem introduced by Chechik et al. in [ESA 2013] models a situation where a sensitive information has to be transmitted between a pair of nodes along a path in a network. The measure of the quality of ...Conference object 
Bchromatic number: Beyond NPhardness
(Dagstuhl Publishing, 2015)The bchromatic number of a graph G, chi_b(G), is the largest integer k such that G has a kvertex coloring with the property that each color class has a vertex which is adjacent to at least one vertex in each of the other ...Conference object 
Additive Schwarz preconditioner for the finite volume element discretization of symmetric elliptic problems
(Springer Netherlands, 20150925)A symmetric and a nonsymmetric variant of the additive Schwarz preconditioner are proposed for the solution of a class of finite volume element discretization of the symmetric elliptic problem in two dimensions, with large ...Journal article 
Quick but odd growth of cacti
(Dagstuhl Publishing, 2015)Let F be a family of graphs. Given an input graph G and a positive integer k, testing whether G has a ksized subset of vertices S, such that G\S belongs to F, is a prototype vertex deletion problem. These type of problems ...Conference object 
Growth and diel vertical migration patterns of the toxic dinoflagellate Protoceratium reticulatum in a water column with salinity stratification: the role of bioconvection and light
(MEPS, 20151112)Novel data on growth and migratory behaviour of a southern Norwegian strain of Protoceratium reticulatum (Dinophyceae) were obtained from longlasting (1422 d) experiments in a water column with salinity gradient (ΔS = 4 ...Journal article 
A diagram of wind speed versus airsea temperature difference to understand the marine atmospheric boundary layer
(Elsevier, 20150828)This contribution reviews the dynamics in the marine atmospheric boundary layer (MABL) with a diagnostic diagram: wind speed versus airsea temperature difference or UΔT. The diagram was first used by Alfred Woodcock in ...Journal article 
A statistical gapfilling method to interpolate global monthly surface ocean carbon dioxide data
(AGU Publications, 20151024)We have developed a statistical gapfilling method adapted to the specific coverage and properties of observed fugacity of surface ocean CO2 (fCO2). We have used this method to interpolate the Surface Ocean CO2 Atlas (SOCAT) ...Journal article 
Meterscale spark Xray spectrum statistics
(AGU Publications, 20151113)Xray emission by sparks implies bremsstrahlung from a population of energetic electrons, but the details of this process remain a mystery. We present detailed statistical analysis of Xray spectra detected by multiple ...Journal article 
Isavsmelting og postglaciale flaumskredvifter i Arna, Hordaland
(The University of Bergen, 1975)Master thesis 
The interaction between transpolar arcs and cusp spots
(AGU Publications, 20151125)Transpolar arcs and cusp spots are both auroral phenomena which occur when the interplanetary magnetic field is northward. Transpolar arcs are associated with magnetic reconnection in the magnetotail, which closes magnetic ...Journal article