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Technical Conditions (technical + condition)
Selected AbstractsOn d -threshold graphs and d -dimensional bin packingNETWORKS: AN INTERNATIONAL JOURNAL, Issue 4 2004Alberto Caprara Abstract We illustrate efficient algorithms to find a maximum stable set and a maximum matching in a graph with n nodes given by the edge union of d threshold graphs on the same node set, in case the d graphs in the union are known. Actually, because the edge set of a threshold graph can be implicitly represented by assigning values to the nodes, we assume that we know these values for each of the d graphs in the union. We present an O(n log n + nd,1) time algorithm to find a maximum stable set and an O(n2) time algorithm to find a maximum matching, in case d is constant. For the case d = 2, the running time of the latter is reduced to O(n log n) provided an additional technical condition is satisfied. The natural application of our results is the fast computation of lower bounds for the d -dimensional bin packing problem, for which the compatibility relations between items are represented by the edge union of d threshold graphs with one node for each item, the value of the node for the i -th graph being equal to the size of the item on the i -th dimension. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 266,280 2004 [source] Linear lower bounds for ,c(p) for a class of 2D self-destructive percolation modelsRANDOM STRUCTURES AND ALGORITHMS, Issue 4 2009J. van den Berg Abstract The self-destructive percolation model is defined as follows: Consider percolation with parameter p > pc. Remove the infinite occupied cluster. Finally, give each vertex (or, for bond percolation, each edge) that at this stage is vacant, an extra chance , to become occupied. Let ,c(p) be the minimal value of ,, needed to obtain an infinite occupied cluster in the final configuration. This model was introduced by van den Berg and Brouwer. They showed, for the site model on the square lattice (and a few other 2D lattices satisfying a special technical condition) that ,c(p) , . In particular, ,c(p) is at least linear in p , pc. Although the arguments used by van den Berg and Brouwer look very lattice-specific, we show that they can be suitably modified to obtain similar linear lower bounds for ,c(p) (with p near pc) for a much larger class of 2D lattices, including bond percolation on the square and triangular lattices, and site percolation on the star lattice (or matching lattice) of the square lattice. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009 [source] Does the method of data collection affect patients' evaluations of quality of care?INTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 6 2000Bodil Wilde Larsson RNT The aim of the study was to compare two methods of data collection,personal interviews and self-administered questionnaires,with patients' evaluations of the quality of care they received. The sample consisted of 41 matched pairs of inpatients at a medical clinic. In each pair, one patient was interviewed and one responded to a questionnaire. Data were collected using the questionnaire ,Quality from the Patients Perspective' (QPP). The QPP consists of 54 items designed to measure the following four quality dimensions: (i) the medical,technical competence and (ii) the degree of identityorientation in the action of the caregivers; (iii) the physical,technical conditions; and (iv) the sociocultural atmosphere of the care organization. Results showed that patients who were interviewed had significantly less favourable scores on the ,softer' quality dimension scales,the identity-oriented approach of the caregivers and the sociocultural atmosphere of the care setting. Possible reasons for this were discussed, including the possibility that the questions designed to measure these two dimensions were more abstract and emotionally loaded than the items of the other two quality dimensions. [source] Influence of extraction temperature on the final quality of espresso coffee,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2003Susana Andueza Abstract The final quality of espresso coffee (EC) depends upon certain technical conditions, such as the extraction temperature used in preparing it. The aim of this work was to investigate the effects of water temperature (88, 92, 96 and 98,°C) on the final quality of three types of EC (Arabica, Robusta Natural blend and Robusta Torrefacto blend) in order to select the optimal temperature. Volatile compound (analysed by Static headspace gas chromatography/mass spectrometry) and sensory flavour profiles were the most relevant parameters, whereas physicochemical, taste and mouthfeel parameters were not very useful for selecting the water temperature. For Arabica and Robusta Natural blend ECs, 92,°C was the optimal water temperature. For Robusta Torrefacto blend EC the overall acceptability might lead to the selection of 88,°C as the ideal water temperature, but the high percentages of key odorants related to roasty and earthy/musty flavours and the ,not hot enough' perception dictated the selection of 92,°C in this case as well. © 2003 Society of Chemical Industry [source] Does a ,volume-filling effect' always prevent chemotactic collapse?MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 1 2010Michael Winkler Abstract The parabolic,parabolic Keller,Segel system for chemotaxis phenomena, is considered under homogeneous Neumann boundary conditions in a smooth bounded domain ,,,n with n,2. It is proved that if ,(u)/,(u) grows faster than u2/n as u,, and some further technical conditions are fulfilled, then there exist solutions that blow up in either finite or infinite time. Here, the total mass ,,u(x, t)dx may attain arbitrarily small positive values. In particular, in the framework of chemotaxis models incorporating a volume-filling effect in the sense of Painter and Hillen (Can. Appl. Math. Q. 2002; 10(4):501,543), the results indicate how strongly the cellular movement must be inhibited at large cell densities in order to rule out chemotactic collapse. Copyright © 2009 John Wiley & Sons, Ltd. [source] The Genetic Mechanism and Model of Deep-Basin Gas Accumulation and Methods for Predicting the Favorable AreasACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2003WANG Tao Abstract, As a kind of abnormal natural gas formed with special mechanism, the deep-basin gas, accumulated in the lower parts of a basin or syncline and trapped by a tight reservoir, has such characteristics as gas-water inversion, abnormal pressure, continuous distribution and tremendous reserves. Being a geological product of the evolution of petroliferous basins by the end of the middle-late stages, the formation of a deep-basin gas accumulation must meet four conditions, i.e., continuous and sufficient gas supply, tight reservoirs in continuous distribution, good sealing caps and stable structures. The areas, where the expansion force of natural gas is smaller than the sum of the capillary force and the hydrostatic pressure within tight reservoirs, are favorable for forming deep-basin gas pools. The range delineated by the above two forces corresponds to that of the deep-basin gas trap. Within the scope of the deep-basin gas trap, the balance relationship between the amounts of ingoing and overflowing gases determines the gas-bearing area of the deep-basin gas pool. The gas volume in regions with high porosity and high permeability is worth exploring under current technical conditions and it is equivalent to the practical resources (about 10%-20% of the deep-basin gas). Based on studies of deep-basin gas formation conditions, the theory of force balance and the equation of material balance, the favorable areas and gas-containing ranges, as well as possible gas-rich regions are preliminarily predicted in the deep-basin gas pools in the Upper Paleozoic He-8 segment of the Ordos basin. [source] | ||||||||||