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91.
92.
Bert Bettonvil Enrique del Castillo Jack P.C. Kleijnen 《European Journal of Operational Research》2009
This article studies simulation-based optimization with multiple outputs. It assumes that the simulation model has one random objective function and must satisfy given constraints on the other random outputs. It presents a statistical procedure for testing whether a specific input combination (proposed by some optimization heuristic) satisfies the Karush–Kuhn–Tucker (KKT) first-order optimality conditions. The article focuses on “expensive” simulations, which have small sample sizes. The article applies the classic t test to check whether the specific input combination is feasible, and whether any constraints are binding; next, it applies bootstrapping (resampling) to test the estimated gradients in the KKT conditions. The new methodology is applied to three examples, which gives encouraging empirical results. 相似文献
93.
Rate constant ratios, kd/kc for the disproportionation/combination reaction have been measured as 0.07 ± 0.02 when an H is removed from the CH2 position of the CF3CH2CHCH3 radical and as 0.24 ± 0.03 when the H is removed from the CH3 position in the reaction with the CF3 radical. For the self‐reaction between two CF3CH2CHCH3 radicals, kd/kc has been measured as 0.27 ± 0.03 when the H is removed from the CH2 position and as 0.47 ± 0.04 when the H is removed from the CH3 position. The branching fraction, corrected for the number of hydrogens at each site, is 0.70 favoring the methyl position when the acceptor radical is CF3 and 0.54 when CF3CH2CHCH3 is the acceptor radical. Branching fraction results show that the CF3 substituent on the CF3CH2CHCH3 radical hinders disproportionation when CF3 is the acceptor radical. When the accepting radical is CF3CH2CHCH3 the CF3 substituent may slightly impede the disproportionation reaction, but the branching ratio is nearly statistical. The effect of substituents on the donor radical, CF3CH2CHX, will be discussed for the series X = H, CF3, Cl, and CH3 when the acceptor radical is CF3. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 549–557, 2001 相似文献
94.
Robert Gallant Bert L. Hartnell Douglas F. Rall 《Discrete Applied Mathematics》2010,158(12):1357-1113
We define a k-limited packing in a graph, which generalizes a 2-packing in a graph, and give several bounds on the size of a k-limited packing. One such bound involves the domination number of the graph, and here we show all trees attaining the bound can be built via a simple sequence of operations. We consider graphs where every maximal 2-limited packing is a maximum 2-limited packing, and characterize their structure in a number of cases. 相似文献
95.
P. Bert 《Fresenius' Journal of Analytical Chemistry》1876,15(1):112-113
Ohne Zusammenfassung 相似文献
96.
97.
José Bento Borba da Silva Maria Bert?lia Oss Giacomelli Ivan Gonçalves de Souza Adilson José Curtius 《Microchemical Journal》1998,60(3):249-257
Performance of graphite platforms coated with Ir, Rh, and a mixture of both, as permanent modifiers for Ag, As, Bi, Cd, and Sb, was evaluated. The coating process is very simple: a solution containing Ir, Rh, or a mixture of both is pipetted on the platform inserted in a graphite tube, and this is submitted to a temperature program. High pyrolysis temperatures are allowed, especially for As and Bi, 1400°C, in the Ir + Rh-coated platform. The sensitivity remains about the same for all analytes with different coatings, except for As in the Ir-coated platform, for which a remarkable gain was obtained in comparison to the other coatings. The lifetimes of the treated tubes were in the range 50 to more than 1000 cycles, being especially long for Sb and Ag in the Rh-coated platform, more than 600 and 1000 cycles, respectively. The Rh coating could not be used for Bi and Cd. Analysis of a certified reference water and of acid oyster tissue digests showed the absence of interference and good precision. Advantages of the permanent coatings are the possibility of low blanks byin situcleaning of the modifier and shorter analysis time. 相似文献
98.
99.
Fausto Di Biase Bert Fischer Rü diger L. Urbanke 《Proceedings of the American Mathematical Society》1998,126(5):1487-1490
It is known that the set of twist points in the boundary of the von Koch snowflake domain has full harmonic measure. We provide a new, simple proof, based on the doubling property of the harmonic measure, and on the existence of an equivalent measure, invariant and ergodic with respect to the shift.
100.
Nijland HA Hartemink S van Kamp I van Wee B 《The Journal of the Acoustical Society of America》2007,122(3):1595
People move to another house for different reasons. It is sometimes presumed that a process of self-selection might take place on the basis of noise sensitivity, i.e., sensitive people would either leave high noise areas or not move into these areas in the first place. Thus, a "survivor population" would remain in the high noise areas. This research aims to investigate whether such a process can be observed in the Netherlands. The study does not show evidence of a process of self-selection based on noise sensitivity. Nevertheless, the results suggest that noise-sensitive people are less satisfied with their living environment and are more willing to move than those who are not noise sensitive. Due to the limited sample size, external validity is limited. 相似文献