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41.
Modeling wildfire propagation with Delaunay triangulation and shortest path algorithms 总被引:1,自引:0,他引:1
Alexander Stepanov James MacGregor Smith 《European Journal of Operational Research》2012,218(3):775-788
In this paper, a methodology for modeling surface wildfire propagation through a complex landscape is presented. The methodology utilizes a Delaunay triangulation to represent surface fire spread within the landscape. A procedure to construct the graph and estimate the rate of spread along the edges of a network is discussed. After the Delaunay data structure is constructed, a two pass shortest path algorithm is incorporated to estimate the minimum travel time paths and fire arrival times. Experimental results are also included. 相似文献
42.
D. G. Middleton J. R. M. Annand C. Barbieri C. Giusti P. Grabmayr T. Hehl I. J. D. MacGregor I. Martin J. C. McGeorge F. Moschini F. D. Pacati M. Schwamb D. Watts 《The European Physical Journal A - Hadrons and Nuclei》2010,43(2):137-143
After recent improvements to the Pavia model of two-nucleon knockout from 16O with electromagnetic probes the calculated cross-sections are compared to experimental data from such reactions. Comparison with data from a measurement of the 16O (e,e’ pn) reaction cross-section shows much better agreement between the experimental data and the results of the theoretical model than was previously observed. In a comparison with recent data from a measurement of the 16O ( $ \gamma$ ,pn) reaction cross-section the model over-predicts the measured cross-section at low missing momentum. 相似文献
43.
S. Schumann B. Boillat E. J. Downie P. Aguar-Bartolomé J. Ahrens J. R. M. Annand H. J. Arends R. Beck V. Bekrenev A. Braghieri D. Branford W. J. Briscoe J. W. Brudvik S. Cherepnya R. Codling P. Drexler L. V. Fil’kov D. I. Glazier R. Gregor E. Heid D. Hornidge O. Jahn V. L. Kashevarov R. Kondratiev M. Korolija M. Kotulla D. Krambrich B. Krusche M. Lang V. Lisin K. Livingston S. Lugert I. J. D. MacGregor D. M. Manley M. Martinez-Fabregate J. C. McGeorge D. Mekterovic V. Metag B. M. K. Nefkens A. Nikolaev R. Novotny M. Ostrick R. O. Owens P. Pedroni A. Polonski S. N. Prakhov J. W. Price G. Rosner M. Rost T. Rostomyan D. Sober A. Starostin I. Supek C. M. Tarbert A. Thomas M. Unverzagt Th. Walcher D. P. Watts F. Zehr 《The European Physical Journal A - Hadrons and Nuclei》2010,43(3):269-282
The reaction γp → pπ 0γ′ has been measured with the Crystal Ball/TAPS detectors using the energy-tagged photon beam at the electron accelerator facility MAMI-B. Energy and angular differential cross-sections for the emitted photon γ′ and angular differential cross-sections for the π0 have been determined with high statistics in the energy range of the Δ+ (1232)-resonance. Cross-sections and the ratio of the cross-section to the nonradiative process γp → pπ 0 are compared to theoretical reaction models, having the anomalous magnetic moment κ Δ as free parameter. As the shape of the experimental distributions is not reproduced in detail by the model calculations, currently no extraction of κ Δ is feasible. 相似文献
44.
45.
Kinetics and Catalysis - Kinetic study of cholesterol oxidation has been studied using a series of N-cetylpicolinium dichromates (CPDC), a class of phase transfer oxidants, in acetic acid medium... 相似文献
46.
M. Unverzagt P. Aguar-Bartolomé J. Ahrens J. R. M. Annand H. J. Arends R. Beck V. Bekrenev B. Boillat A. Braghieri D. Branford W. J. Briscoe J. W. Brudvik S. Cherepnya R. Codling E. J. Downie L. V. Fil’kov D. I. Glazier R. Gregor E. Heid D. Hornidge O. Jahn V. L. Kashevarov R. Kondratiev M. Korolija M. Kotulla D. Krambrich B. Krusche M. Lang V. Lisin K. Livingston S. Lugert I. J. D. MacGregor D. M. Manley M. Martinez-Fabregate J. C. McGeorge D. Mekterovic V. Metag B. M. K. Nefkens A. Nikolaev R. Novotny R. O. Owens P. Pedroni A. Polonski S. N. Prakhov J. W. Price G. Rosner M. Rost T. Rostomyan S. Schumann D. Sober A. Starostin I. Supek C. M. Tarbert A. Thomas Th. Walcher D. P. Watts F. Zehr 《The European Physical Journal A - Hadrons and Nuclei》2009,39(2):169-177
A precise measurement of the Dalitz plot parameter, $ \alpha$ , for the $ \eta$ → 3 $ \pi^{0}_{}$ decay is presented. The experiment was performed with the Crystal Ball and TAPS large-acceptance photon detectors at the tagged photon beam facility of the MAMI-B electron accelerator in Mainz. High statistics of 1.8 · 106 $ \eta$ → 3 $ \pi^{0}_{}$ events were obtained, giving the result $ \alpha$ = - 0.032±0.002stat±0.002syst . 相似文献
47.
Queueing networks with finite buffers, multiple servers, arbitrary acyclic, series‐parallel topologies, and general service time distributions are considered in this paper. An approach to optimally allocate servers to series, merge, and split topologies and their combinations is demonstrated. The methodology builds on two‐moment approximations to the service time distribution embedded in the generalized expansion method for computing the performance measures in complex finite queueing networks and Powell's algorithm for optimally allocating servers to the network topology. Convexity of the objective function along with results from computational experiments is presented for showing the efficacy of the methodology. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
48.
49.
Thomas H. MacGregor 《Journal of Mathematical Analysis and Applications》2003,282(1):163-176
We consider Hadamard products of power functions P(z)=(1−z)−b with functions analytic in the open unit disk in the complex plane, and an integral representation is obtained when 0<Reb<2. Let where μ is a complex-valued measure on the closed unit disk Such sequences are shown to be multipliers of Hp for 1?p?∞. Moreover, if the support of μ is contained in a finite set of Stolz angles with vertices on the unit circle, we prove that {μn} is a multiplier of Hp for every p>0. When the support of μ is [0,1] we get the multiplier sequence which provides more concrete applications. We show that if the sequences {μn} and {νn} are related by an asymptotic expansion
50.
F. Bloch J. Ahrens J. R. M. Annand R. Beck L. S. Fog D. Hornidge S. Janssen M. Kotulla B. Krusche J. C. McGeorge I. J. D. MacGregor J. G. Messchendorp V. Metag R. Novotny R. O. Owens M. Pfeiffer M. Rost R. Sanderson S. Schadmand A. Thomas D. P. Watts 《The European Physical Journal A - Hadrons and Nuclei》2007,32(2):219-228
The photoproduction of π
0
π
0 and π
0
π
± pairs off 40Ca has been investigated with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI accelerator.
Data have been taken for incident photon energies in the energy range from 200-820MeV. Total cross-sections have been extracted
from threshold up to the maximum photon energy and invariant-mass distributions of the pion pairs have been obtained for incident
photon energies between 400-500MeV and 500-550MeV. The double π
0 invariant-mass distributions show some relative enhancement with respect to the mixed charge channel at small invariant masses.
The effects are smaller than previously observed for lead nuclei and the distributions do not significantly deviate from carbon
data. The data are in good agreement with the results of recent calculations in the framework of the BUU model, with careful
treatment of final-state interaction effects but without an explicit in-medium modification of scalar, iso-scalar pion pairs.
This means that for Ca most of the experimentally observed effect can be explained by final-state interactions. Only at low
incident photon energies there is still a small low mass enhancement of the double π
0 data over the BUU results. 相似文献