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排序方式: 共有1988条查询结果,搜索用时 375 毫秒
241.
Two cellular automata (CA) models that evaluate the s–t connectedness and shortest path in a network are presented. CA based algorithms enhance the performance of classical algorithms, since they allow a more reliable and straightforward parallel implementation resulting in a dynamic network evaluation, where changes in the connectivity and/or link costs can readily be incorporated avoiding recalculation from scratch. The paper also demonstrates how these algorithms can be applied for network reliability evaluation (based on Monte-Carlo approach) and for finding s–t path with maximal reliability. 相似文献
242.
Static analysis of a Bickford beam by means of the DQEM 总被引:4,自引:0,他引:4
Claudio Franciosi Stefania Tomasiello 《International Journal of Mechanical Sciences》2007,49(1):122-128
In this paper the recently proposed differential quadrature element method is employed in order to solve the equilibrium equations of a higher-order beam. A simple five-node element is introduced, in which the vertical displacement is approximated by a sixth-order polynomial, whereas the rotation is consistently approximated by a fourth-order polynomial, and the resulting weighting coefficient matrix is given. Moreover, a general procedure is outlined, for an N-node element, in which vertical displacements and rotations are given by polynomials of order N+1 and N-1, respectively. Numerical examples are aimed both at checking the convergence of the results for increasing values of the nodes, and at comparing the used cubic beam theory with the simpler, linear, Timoshenko theory. 相似文献
243.
Mauro Rajteri Claudio Gandini Eugenio Monticone Chiara Portesi Aldo Masoero Chiara Boveri Piero Mazzetti 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2004,520(1-3):351-353
In this paper we present some experimental results concerning the current noise produced during the resistive transition in MgB2 thin films. Preliminary investigations evidenced the presence of electrical noise whose power spectrum has a region of the 1/fn type with n 3. We suggest that the noise may originate from abrupt rearrangement of the current distribution inside the specimen during the percolative process of a diphasic system. Experimental measurements of the spectral components of the current noise taken during the resistive transition will be given and discussed. 相似文献
244.
Solving advanced network reliability problems by means of cellular automata and Monte Carlo sampling 总被引:2,自引:1,他引:1
This paper extends the cellular automata-based, Monte Carlo sampling methodology for computing network reliability, previously proposed by the first author. The extension regards the development of cellular automata for the solution of the all-terminal and k-terminal connection problems and the maximum unsplittable flow problem, which can be considered as a particular, simplified case of the maximum flow distribution problem. The algorithms developed are presented in detail and verified on literature cases. 相似文献
245.
Erick R. Bandala Camilo A. Arancibia-Bulnes Sayra L. Orozco Claudio A. Estrada 《Solar Energy》2004,77(5):503-512
Solar heterogeneous photocatalytic degradation of oxalic acid in water is carried out in four different solar photoreactors: a parabolic trough concentrator (PC), a tubular collector (TC), a compound parabolic collector (CPC), and a V-trough collector (VC). The reactors operate under equal conditions of solar irradiance, collection surface and fluid flow rate to ensure a better comparison between the systems. The effects of TiO2 catalyst concentration and radiation incidence angle on the degradation are studied. Oxalic acid degrades without appreciable generation of intermediates, and a simple kinetic model is proposed to describe the process. There are differences in the degradation rates depending on the collector geometry. The CPC shows the best overall performance in terms of accumulated energy, followed closely by the VC. Incidence angle affects the total amount of energy collected but does not reduce very much the efficiency of the reactors to use this energy in the photocatalytic process. 相似文献
246.
247.
Maurizio Bianchi Federico Ferioli Massimiliano Petracci Maria Fiorenza Caboni Claudio Cavani 《European Food Research and Technology》2009,229(2):339-348
The influence of dietary lipid source [animal fats (AF) and vegetable oils (VO)] on quality characteristics of raw chicken
meat (breast, thigh and meat batter) and cooked breaded patties prepared using a conventional technology (CT; forming, battering,
breading, frying and convection cooking) or innovative technology (IT; forming, pre-dusting, steam cooking, battering and
frying) was evaluated. Overall, dietary lipid source did not influence the chemical composition of raw meat while it modified its colour (L*, a*, b*). With respect to AF, VO produced higher breast and thigh meat cooking losses as well as a lower moisture and
higher protein content of cooked breaded patties. VO also determined an increase of polyunsaturated-to-saturated fatty acid
ratio of both raw and processed meat. Despite the different fatty acid profiles, the oxidative status of lipids was not affected
by dietary lipid source and was acceptable in both raw meat and cooked patties as indicated by peroxide and thiobarbituric
acid reactive substance values. As for the processing technology, IT determined a higher moisture and lower lipid content
of the cooked breaded patties. Moreover, lipolysis degree was slightly higher in the products coming from IT. Finally, patties
from AF group were lighter and more yellow than products belonging to VO group whereas IT led to lighter, less red and more
yellow patties in comparison to CT. 相似文献
248.
Claudio Toniolo 《Polymer International》1986,18(4):221-225
A theoretical and experimental analysis of the preferred conformations of homo-peptides from Cα,α-dialkylated glycines revealed that these compounds are characterised by a marked structural versatility. Fully extended (C5-conformations). folded (of theβ-bend type), and 310-helical structures are adopted as a function of side-chain nature. Dimethylated and cyclic side chains favour folded and helical structures, whereas diethylated and longer acyclic side chains favour the fully extended structure. By means of conformational energy calculations the preferred screw sense of the helical structure of homo-peptides from a representative chiral acyclic residue is also anticipated. 相似文献
249.
Claudio de A. Loural Romulo A. Zanco Filho Antonio Carlos G. Bordeaux Rego Rogrio C. de Oliveira 《Telematics and Informatics》2006,23(4):294-315
Brazilian telecommunications sector has undergone important modifications in the last 40 years. From a badly structured system of municipal level operators in 1960, with barely one million fixed lines to a large, nation-wide system with about 50 million fixed plus another 75 million mobile lines in 2005. This work paper reviews the institutional framework of telecommunications industrial and technological policy in Brazil in the last four decades, its results and present situation. Infrastructure and services modernisation and expansion process that happened in early 1970s were carried out at the expense of massive import of products and technology. A government strategy was, then, devised to stimulate local industrial and technological development in telecommunications, under the general guidelines of import substitution policy. Essential to this strategy was the creation of an innovation system around TELEBRÁS Research and Development Centre. This technological development model was successful while a protectionist economic policy existed. When economic and political circumstances could not anymore sustain an import substitution approach, in the 1990-decade, the model fell apart and has not been replaced by any other sectorial policy. A critical assessment is carried out, analysing the adopted actions in face of the digital technology maturing process that occurred in meantime. 相似文献
250.
Oliverio Alberto; Castellano Claudio; Messeri Patrizia 《Canadian Metallurgical Quarterly》1972,79(3):459
Conducted a genetic analysis of avoidance, maze learning, and wheel-running activity in 1,573 SEC/1ReJ, DBA/2J, and C57BL/6J strain mice and their F1, F2, and F3 progenies. Results show that the mode of inheritance in a given behavioral measure depends on the crosses considered. Thus, a given allele may be dominant in a given hybrid combination and recessive in another combination. The significant genetic correlations between these 3 behavioral measures suggest that these traits could be influenced by some of the same genes. The estimates of heritability are larger for avoidance than for activity, suggesting that the latter trait is more related to fitness. (36 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献