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31.
This paper studies the problem of how changes in the design of the genetic algorithm (GA) have an effect on the results obtained in real-life applications. In this study, focused on the application of a GA to the tuning of technical trading rules in the context of financial markets, our tentative thesis is that the GA is robust with respect to design changes. The optimization of technical trading systems is a suitable area for the application of the GA metaheuristic, as the complexity of the problem grows exponentially as new technical rules are added to the system and as the answer time is crucial when applying the system to real-time data. Up to now, most of GAs applications to this subject obviated the question of possible “design dependence” in their results. The data we report, based on our experiments, do not allow us to refute the hypothesis of robustness of the GA to design implementation, when applying to technical trading systems tuning. 相似文献
32.
Arne Pfeilsticker 《Fuzzy Sets and Systems》1981,6(3):209-233
Ideas are presented to show how fuzzy mathematics can be applied in macro-economics in combination with the systems approach in order to bridge the gap between mathematical and language-oriented economists.Two reasons are given.From a mathematical point of view, fuzzy sets, fuzzy relations and fuzzy logic are not fuzzy at all. They are all well defined, but tend to be more complicated than traditional, mathematical concepts used in economics.From a language-oriented economist's point of view, fuzzy sets, etc. are used to express mathematically the type of concepts which are typical in language and most valuable in dealing with complex systems like an economy.The paper deals with economics in general terms, but examples are provided to illustrate the ideas. 相似文献
33.
A stochastic production frontier method is used to examine technical efficiency among Indian vacuum-pan sugar factories over a five-year period. Most factories are close to Indian best practice in terms of technical efficiency. Smaller firms and firms with access to sweeter cane are likely to be more efficient than other firms, while publicly owned firms are less efficient. There are transitory positive effects of a long crushing season on technical efficiency. 相似文献
34.
Geometric Programming is extended to include convex quadratic functions. Generalized Geometric Programming is applied to this
class of programs to obtain a convex dual program. Machining economics problems fall into this class. Such problems are studied
by applying this duality to a nested set of three problems. One problem is zero degree of difficulty and the solution is obtained
by solving a simple system of equations. The inclusion of a constraint restricting the force on the tool to be less than or
equal to the breaking force provides a more realistic solution. This model is solved as a program with one degree of difficulty.
Finally the behavior of the machining cost per part is studied parametrically as a function of axial depth.
This research was supported by the Air Force Office of Scientific Research Grant AFOSR-83-0234 相似文献
35.
Precipitate-type electrodes (benzidine sulfate or phosphate and hexammino-cobalt(III) nitrate in silicone rubber), and liquid ion-exchanger electrodes based on quaternary ammonium and phosphonium and triphenyltin salts were tested for the assay of phosphate ions. Good sensitivity was achieved with the phosphonium and triphenyltin salts, but both lacked sufficient selectivity for routine-assays. 相似文献
36.
L. Bezur J. Marshall J.M. Ottaway 《Spectrochimica Acta Part B: Atomic Spectroscopy》1984,39(6):787-805
A square-wave wavelength modulation system, based on a rotating quartz chopper with four quadrants of different thicknesses, has been developed and evaluated as a method for automatic background correction in carbon furnace atomic emission spectrometry. Accurate background correction is achieved for the residual black body radiation (Rayleigh scatter) from the tube wall and Mie scatter from particles generated by a sample matrix and formed by condensation of atoms in the optical path. Intensity modulation caused by overlap at the edges of the quartz plates and by the divergence of the optical beam at the position of the modulation chopper has been investigated and is likely to be small. 相似文献
37.
S.-Y. Ma S.-Q. Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,72(4):567-573
We show that a simple model of a spatially resolved
evolving economic system, which has a steady state under
simultaneous updating, shows stable oscillations in price when
updated asynchronously. The oscillations arise from a gradual
decline of the mean price due to competition among sellers competing
for the same resource. This lowers profitability and hence
population but is followed by a sharp rise as speculative sellers
invade the large un-inhabited areas. This cycle then begins again. 相似文献
38.
M. Gligor M. Ausloos 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(4):533-539
GDP/capita correlations are investigated in various time windows (TW), for the time interval 1990–2005. The target group of
countries is the set of 25 EU members, 15 till 2004 plus the 10 countries which joined EU later on. The TW-means of the statistical
correlation coefficients are taken as the weights (links) of a fully connected network having the countries as nodes. Thereafter
we define and introduce the overlapping index of weighted network nodes. A cluster structure of EU countries is derived from the statistically relevant eigenvalues and
eigenvectors of the adjacency matrix. This may be considered to yield some information about the structure, stability and
evolution of the EU country clusters in a macroeconomic sense. 相似文献
39.
J. B. Satinover D. Sornette 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(3):369-384
Human beings like to believe they are in control of their
destiny. This ubiquitous trait seems to increase motivation and persistence,
and is probably evolutionarily adaptive [J.D. Taylor, S.E. Brown, Psych. Bull. 103, 193 (1988); A. Bandura,
Self-efficacy: the exercise of control (WH Freeman, New
York, 1997)]. But how good really is our
ability to control? How successful is our track record in these areas? There
is little understanding of when and under what circumstances we may
over-estimate [E. Langer, J. Pers. Soc. Psych. 7, 185 (1975)] or even lose our ability to control and optimize outcomes,
especially when they are the result of aggregations of individual
optimization processes. Here, we demonstrate analytically using the theory
of Markov Chains and by numerical simulations in two classes of games, the
Time-Horizon Minority Game [M.L. Hart, P. Jefferies, N.F. Johnson, Phys. A 311, 275 (2002)] and the Parrondo Game
[J.M.R. Parrondo, G.P. Harmer, D. Abbott, Phys. Rev. Lett.
85, 5226 (2000); J.M.R. Parrondo, How to cheat a bad mathematician (ISI, Italy, 1996)], that agents
who optimize their strategy based on past information may actually perform
worse than non-optimizing agents. In other words, low-entropy (more
informative) strategies under-perform high-entropy (or random) strategies.
This provides a precise definition of the “illusion of control” in certain
set-ups a priori defined to emphasize the importance of optimization.
An erratum to this article is available at . 相似文献
40.
S. M.D. Queirós L. G. Moyano J. de Souza C. Tsallis 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(2):161-167
We present results about financial market observables, specifically
returns and traded volumes. They are obtained within the current nonextensive statistical mechanical framework based on the
entropy
. More precisely, we present stochastic dynamical mechanisms which mimic probability density functions empirically observed.
These mechanisms provide possible interpretations for the emergence of the entropic
indices q in the time evolution of the corresponding observables. In addition to this, through multi-fractal analysis of return
time series, we verify that the dual relation qstat+qsens=2 is numerically satisfied, qstat and qsens being associated to the probability density function and to the sensitivity to initial conditions respectively. This type
of simple relation, whose understanding remains ellusive, has been empirically verified in various other systems. 相似文献