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131.
M. Bartolozzi 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(3):337-345
Avalanches, or Avalanche-like, events are often
observed in the dynamical behaviour of many complex systems which
span from solar flaring to the Earth's crust dynamics and from
traffic flows to financial markets. Self-organized criticality
(SOC) is one of the most popular theories able to explain this
intermittent charge/discharge behaviour. Despite a large amount of
theoretical work, empirical tests for SOC are still in their
infancy. In the present paper we address the common problem of
revealing SOC from a simple time series without having much
information about the underlying system. As a working example we
use a modified version of the multifractal random walk originally
proposed as a model for the stock market dynamics. The study
reveals, despite the lack of the typical ingredients of SOC, an
avalanche-like dynamics similar to that of many physical systems.
While, on one hand, the results confirm the relevance of cascade
models in representing turbulent-like phenomena, on the other,
they also raise the question about the current state of
reliability of SOC inference from time series analysis. 相似文献
132.
针对kJ级大能量钕玻璃固体脉冲激光器,对比研究了传统恒温水冷方式和采用加热控制的新型热管理技术下的激光棒温度分布情况。结果表明,采用新型热管理技术可大大降低棒内温度梯度,减小泵浦过程中的热效应,确保大能量激光输出;而且加热循环水的最佳升温值在单泵浦脉冲引起的激光棒平均温升值附近,使得径向温差最小,该最佳升温值与脉冲间隔时间有关,比如脉冲间隔15 s时,循环水在每个脉冲过后的最佳升温值为单泵浦脉冲引起的激光棒平均温升值的0.85倍;采用加热控制后水温和激光棒温度整体升高,因此在工作一个脉冲串后,必须恢复激光棒温度到初始状态,然后再进行下一个脉冲串工作。 相似文献
133.
The nonlinear Schrödinger equation which governs the dynamics of two-dimensional spatial solitons in Kerr media with periodically varying diffraction and nonlinearity has been analyzed in this paper using variational approach and numerical studies. Analytical expressions for soliton parameters have been derived using variational analysis. Variational equations and partial differential equation have been simulated numerically. Analytical and numerical studies have shown that nonlinearity management and diffraction management stabilize the pulse against decay or collapse providing undisturbed propagation even for larger energies of the incident beam. 相似文献
134.
T. S. Evans 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):65-69
Evolving networks with a constant number of edges may be
modelled using a rewiring process. These models are used to
describe many real-world processes including the evolution of
cultural artifacts such as family names, the evolution of gene
variations, and the popularity of strategies in simple
econophysics models such as the minority game. The model is
closely related to Urn models used for glasses, quantum gravity
and wealth distributions. The full mean field equation for the
degree distribution is found and its exact solution and generating
solution are given. 相似文献
135.
Z.-Q. Jiang L. Guo W.-X. Zhou 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(3):347-355
A phenomenological investigation of the endogenous and
exogenous dynamics in the fluctuations of capital fluxes is carried
out on the Chinese stock market using mean-variance analysis,
fluctuation analysis, and their generalizations to higher orders.
Non-universal dynamics have been found not only in the scaling
exponent α, which is different from the universal values 1/2
and 1, but also in the distributions of the ratio η=
σexo / σendo of individual stocks. Both
the scaling exponent α of fluctuations and the Hurst exponent
Hi increase in logarithmic form with the time scale Δt
and the mean traded value per minute 〈fi 〉,
respectively. We find that the scaling exponent αendo
of the endogenous fluctuations is independent of the time scale.
Multiscaling and multifractal features are observed in the data as
well. However, the inhomogeneous impact model is not verified. 相似文献
136.
We proposed for the first time the concept of the nano liquid-metal fluid, aiming to establish an engineering route to make the highest conductive coolant. Using several widely accepted theoretical models for characterizing the nano fluid, the thermal conductivity enhancement of the liquid-metal fluid due to addition of more conductive nano particles was predicted. Further, the effects of particle size, cluster of nano particle, solid-like layer due to adsorption, volume fraction and particle types were evaluated. Having the highest conductivity, being electromagnetically drivable, the liquid metal with low melting point is expected to be an idealistic base fluid for making super conductive solution which may lead to the ultimate coolant in a wide variety of heat transfer enhancement area. 相似文献
137.
结合河蟹土池育苗实际,对育苗池塘易出水质问题的时期、主要原因及其表现展开讨论;并对常见水质问题引发的影响及其后果进行了详细剖析.据此,提出了彻底清塘消毒、适时施肥、合理投饲、充分利用增氧机械、适时适量加换新水等育苗池塘水质管理的实用技术,为有效管理水质提供参考. 相似文献
138.
Pricing strategies for perishable products: the case of Vienna and the hotel reservation system hrs.com 总被引:1,自引:0,他引:1
Jörg Schütze 《Central European Journal of Operations Research》2008,16(1):43-66
Consider a retailer who sells perishable products for which there is uncertain demand. Yield management with dynamic pricing
is a standard practice that firms use for revenue management. For perishable products, recent analysis has focused on the
distribution of flight capacity, referred to as ticket sales. Other non- storable, non-transportable, immaterial hospitality products include hotel capacity. The article discusses the
extent to which hotel pricing strategies vary within the internet distribution system hrs.com. This study focuses on the distribution
of hotel rooms available for booking on the internet for Vienna and gives an outlook to Euroland capitals. The main research
interests are the underlying pricing models and the setting of the end price. Data was taken from hrs.com, which is the most
important specialist for hotel room internet distribution in Germany according to recent studies by KMPG and others. The results
include the identification of different pricing strategy clusters with regard to hotel category and hotel availability over
a 22-day period for Vienna and one city from all Euroland countries (the capitals were studied for all cases except for the
Netherlands, for which data was collected for Amsterdam). The study took the arrival days Mondays, Tuesdays, Wednesdays and
Thursdays into account, and used data for all these days from the 11th of July, 2005, to the 10th of October, 2005, for Vienna,
and the first and the last of these dates as a comparison base for the other Euroland cities. 相似文献
139.
高校人力资源管理中的模糊综合评判 总被引:6,自引:0,他引:6
人力资源管理是高校管理的重要组成部分。本简要介绍了高校人力资源的状况,讨论了模糊综合评判理论在人力资源管理中的应用。 相似文献
140.
Ryszard Struzak 《Annals of Operations Research》2001,107(1-4):339-347
This paper addresses the operation of radio links under mutual interference conditions, an important problem in spectrum management and radio link design. It introduces the capacity loss and isolation index as measures of effective use of radio links and radio frequency spectrum resources. 相似文献