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1.
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
2.
F. Wang P. Weber K. Yamasaki S. Havlin H. E. Stanley 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(2):123-133
We discuss recent results concerning statistical regularities in the
return intervals of volatility in financial markets. In particular, we
show how the analysis of volatility return intervals, defined as the
time between two volatilities larger than a given threshold, can help
to get a better understanding of the behavior of financial time
series. We find scaling in the distribution of return intervals for
thresholds ranging over a factor of 25, from 0.6 to 15 standard
deviations, and also for various time windows from one minute up to
390 min (an entire trading day). Moreover, these results are
universal for different stocks, commodities, interest rates as well as
currencies. We also analyze the memory in the return intervals which
relates to the memory in the volatility and find two scaling regimes,
ℓ<ℓ* with α1=0.64±0.02 and ℓ> ℓ*
with α2=0.92±0.04; these exponent values are similar to
results of Liu et al. for the volatility. As an application, we use
the scaling and memory properties of the return intervals to suggest a
possibly useful method for estimating risk. 相似文献
3.
We survey a theory (first sketched in Nature in 2003, then fleshed out in the Quarterly Journal of Economics in 2006) of the economic underpinnings of the fat-tailed distributions of a number of financial variables, such as returns and trading volume. Our theory posits that they have a common origin in the strategic trading behavior of very large financial institutions in a relatively illiquid market. We show how the fat-tailed distribution of fund sizes can indeed generate extreme returns and volumes, even in the absence of fundamental news. Moreover, we are able to replicate the individually different empirical values of the power-law exponents for each distribution: 3 for returns, 3/2 for volumes, 1 for the assets under management of large investors. Large investors moderate their trades to reduce their price impact; coupled with a concave price impact function, this leads to volumes being more fat-tailed than returns but less fat-tailed than fund sizes. The trades of large institutions also offer a unified explanation for apparently disconnected empirical regularities that are otherwise a challenge for economic theory. 相似文献
4.
Z. Eisler J. Kertész 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(1):145-154
We reanalyze high resolution data from the New York Stock
Exchange and find a monotonic (but not power law) variation of the mean value per trade,
the mean number of trades per minute and the mean trading activity
with company capitalization. We show that the second moment of the
traded value distribution is finite. Consequently, the Hurst
exponents for the corresponding time series can be calculated. These
are, however, non-universal: The persistence grows with larger
capitalization and this results in a logarithmically increasing Hurst exponent. A similar
trend is displayed by intertrade time intervals.
Finally, we demonstrate that the distribution of the intertrade times is
better described by a multiscaling ansatz than by simple gap scaling. 相似文献
5.
A dynamic herding model with interactions of trading volumes is introduced. At time t, an agent trades with a probability, which depends on the ratio of the total trading volume at time t−1 to its own trading volume at its last trade. The price return is determined by the volume imbalance and number of trades. The model can reproduce the power-law distributions of the trading volume, number of trades and price return, and the probable relation between them. The exponents are tunable by adjusting the values of the parameters, but show slight deviation from those revealed in empirical studies. Moreover, the time series generated are long-range correlated. We demonstrate that the results are rather robust, and do not depend on the particular form of the trading probability. 相似文献
6.
L. Tian D.-N. Shi 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(2):167-171
In this paper, we study a rank-based model for weighted network. The evolution rule of the network is based on the ranking
of node strength, which couples the topological growth and the weight dynamics. Analytically and by simulations, we demonstrate
that the generated networks recover the scale-free distributions of degree and strength in the whole region of the growth
dynamics parameter (α>0). Moreover, this network evolution mechanism can also produce scale-free property of weight, which
adds deeper comprehension of the networks growth in the presence of incomplete information. We also characterize the clustering
and correlation properties of this class of networks. It is showed that at α=1 a structural phase transition occurs, and for
α>1 the generated network simultaneously exhibits hierarchical organization and disassortative degree correlation, which is
consistent with a wide range of biological networks. 相似文献
7.
G.-F. Gu W.-X. Zhou 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(4):585-592
Recently, Mike and Farmer have constructed a very powerful
and realistic behavioral model to mimick the dynamic process of
stock price formation based on the empirical regularities of order
placement and cancelation in a purely order-driven market, which can
successfully reproduce the whole distribution of returns, not only
the well-known power-law tails, together with several other
important stylized facts. There are three key ingredients in the
Mike-Farmer (MF) model: the long memory of order signs characterized
by the Hurst index Hs, the distribution of relative order prices
x in reference to the same best price described by a Student
distribution (or Tsallis’ q-Gaussian), and the dynamics of order
cancelation. They showed that different values of the Hurst index
Hs and the freedom degree αx of the Student distribution
can always produce power-law tails in the return distribution
fr(r) with different tail exponent αr. In this paper, we
study the origin of the power-law tails of the return distribution
fr(r) in the MF model, based on extensive simulations with
different combinations of the left part L(x) for x < 0 and the
right part R(x) for x > 0 of fx(x). We find that power-law
tails appear only when L(x) has a power-law tail, no matter R(x)
has a power-law tail or not. In addition, we find that the
distributions of returns in the MF model at different timescales can
be well modeled by the Student distributions, whose tail exponents
are close to the well-known cubic law and increase with the
timescale. 相似文献
8.
P. H. Chavanis L. Delfini 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(3):389-429
We apply the Nyquist method to the Hamiltonian mean field (HMF) model in order to settle the linear dynamical stability of
a spatially homogeneous distribution function with respect to the
Vlasov equation. We consider the case of Maxwell (isothermal) and Tsallis (polytropic) distributions and show that the system
is stable above a critical kinetic temperature Tc and unstable below it. Then, we consider a symmetric double-humped distribution, made of the superposition of two decentered
Maxwellians, and show the existence of a re-entrant phase in the stability diagram. When we consider an asymmetric double-humped
distribution, the re-entrant phase disappears above a
critical value of the asymmetry factor Δ > 1.09. We also consider the HMF model with a repulsive interaction. In that case,
single-humped distributions are always stable. For asymmetric double-humped distributions, there is a re-entrant phase for
1 ≤ Δ < 25.6, a double re-entrant phase for 25.6 < Δ < 43.9 and no re-entrant phase for Δ > 43.9. Finally, we extend our results
to arbitrary potentials of interaction and mention the connexion between the HMF model, Coulombian plasmas and gravitational
systems. We discuss the relation between linear dynamical stability and formal nonlinear dynamical stability and show their
equivalence for spatially
homogeneous distributions. We also provide a criterion of dynamical stability for spatially inhomogeneous systems. 相似文献
9.
D. Karevski Y-C. Lin H. Rieger N. Kawashima F. Iglói 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(2):267-276
We study the critical behavior of Ising quantum magnets with broadly distributed random couplings (J), such that P(ln J) ∼ | ln J|-1 - α, α > 1, for large | ln J| (Lévy flight statistics). For sufficiently broad distributions, α < , the critical behavior is controlled by a line of fixed points, where the critical exponents vary with the Lévy index, α.
In one dimension, with = 2, we obtained several exact results through a mapping to surviving Riemann walks. In two dimensions the varying critical
exponents have been calculated by a numerical implementation of the Ma-Dasgupta-Hu renormalization group method leading to
≈ 4.5. Thus in the region 2 < α < , where the central limit theorem holds for | ln J| the broadness of the distribution is relevant for the 2d quantum Ising model.
Received 6 December 2000 and Received in final form 22 January 2001 相似文献
10.
S. Duhot R. Mélin 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(2):257-266
The three-dimensional bimodal random-field Ising model
is investigated using the N-fold version of the Wang-Landau
algorithm. The essential energy subspaces are determined by the
recently developed critical minimum energy subspace technique, and
two implementations of this scheme are utilized. The random fields
are obtained from a bimodal discrete (±Δ) distribution,
and we study the model for various values of the disorder strength
Δ, Δ=0.5,1,1.5 and 2, on cubic lattices with
linear sizes L=4–24. We extract information for the probability
distributions of the specific heat peaks over samples of random
fields. This permits us to obtain the phase diagram and present
the finite-size behavior of the specific heat. The question of
saturation of the specific heat is re-examined and it is shown
that the open problem of universality for the random-field Ising
model is strongly influenced by the lack of self-averaging of the
model. This property appears to be substantially depended on the
disorder strength. 相似文献
11.
Osamu Yamashita Hirotaka Odahara Takahiro Ochi Kouji Satou 《Applied Physics A: Materials Science & Processing》2009,94(1):57-64
The resultant local Seebeck coefficient α
R (=α
S−α
T) at the interface of a thermoelement has not yet been measured, although it is an important factor governing the thermoelectric
efficiency, where α
S is the local Seebeck coefficient and α
T is the one caused by the Thomson effect. It is shown in this paper that α
S, α
T, and α
R of the p- and n-type Cu/Bi–Te/Cu composites are obtained analytically and experimentally on the assumption that the local temperature of
the composite on which the temperature difference ΔT is imposed varies linearly with changes in position along the composite. They were indeed estimated as a function of position
from the local experimental data of R,ΔI,ΔT, and V generated by applying an additional current of ±I to the composite, where R is the electrical resistance and ΔI is a current generated by the composite. As a result, it was found that the absolute values of α
S at the hot interface of the p- and n-type composites are approximately 1.5 and 1.4 times higher than their lowest values in the middle region of the composite,
respectively, while those of α
T are less than 8% of α
S all over the composite and are so small that the relation α
R≈α
S can be held. We thus succeeded in measuring α
R at the interfaces of the composite. 相似文献
12.
Th. Oikonomou A. Provata 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):259-264
We study the primary DNA structure of four of the most completely
sequenced human chromosomes (including chromosome 19 which
is the most dense in coding), using non-extensive statistics. We show that
the exponents governing the spatial decay of the
coding size distributions vary between
5.2 ≤r ≤5.7 for the short scales and 1.45 ≤q ≤1.50
for the large scales. On the contrary,
the exponents governing the spatial decay of the non-coding size distributions
in these four chromosomes, take the values
2.4 ≤r ≤3.2 for the short scales and 1.50 ≤q ≤1.72
for the large scales.
These results,
in particular the values of the tail exponent q, indicate the existence of
correlations in the coding and non-coding size
distributions with tendency for higher correlations
in the non-coding DNA. 相似文献
13.
M. Batty R. Carvalho A. Hudson-Smith R. Milton D. Smith P. Steadman 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(3):303-314
Many aggregate distributions of urban activities such as city
sizes reveal scaling but hardly any work exists on the properties of spatial
distributions within individual cities, notwithstanding considerable
knowledge about their fractal structure. We redress this here by examining
scaling relationships in a world city using data on the geometric properties
of individual buildings. We first summarise how power laws can be used to
approximate the size distributions of buildings, in analogy to city-size
distributions which have been widely studied as rank-size and lognormal
distributions following Zipf [Human Behavior and the Principle of Least Effort (Addison-Wesley, Cambridge, 1949)] and Gibrat [Les Inégalités économiques (Librarie du Recueil Sirey, Paris, 1931)]. We then extend this
analysis to allometric relationships between buildings in terms of their
different geometric size properties. We present some preliminary analysis of
building heights from the Emporis database which suggests very
strong scaling in world cities. The data base for Greater London is then
introduced from which we extract 3.6 million buildings whose scaling
properties we explore. We examine key allometric relationships between these
different properties illustrating how building shape changes according to
size, and we extend this analysis to the classification of buildings
according to land use types. We conclude with an analysis of two-point
correlation functions of building geometries which supports our non-spatial
analysis of scaling. 相似文献
14.
15.
We investigate the statistical properties of the empirical data taken from the Chinese stock market during the time period from January, 2006 to July, 2007. By using the methods of detrended fluctuation analysis (DFA) and calculating correlation coefficients, we acquire the evidence of strong correlations among different stock types, stock index, stock volume turnover, A share (B share) seat number, and GDP per capita. In addition, we study the behavior of “volatility”, which is now defined as the difference between the new account numbers for two consecutive days. It is shown that the empirical power-law of the number of aftershock events exceeding the selected threshold is analogous to the Omori law originally observed in geophysics. Furthermore, we find that the cumulative distributions of stock return, trade volume and trade number are all exponential-like, which does not belong to the universality class of such distributions found by Xavier Gabaix et al. [Xavier Gabaix, Parameswaran Gopikrishnan, Vasiliki Plerou, H. Eugene Stanley, Nature, 423 (2003)] for major western markets. Through the comparison, we draw a conclusion that regardless of developed stock markets or emerging ones, “cubic law of returns” is valid only in the long-term absolute return, and in the short-term one, the distributions are exponential-like. Specifically, the distributions of both trade volume and trade number display distinct decaying behaviors in two separate regimes. Lastly, the scaling behavior of the relation is analyzed between dispersion and the mean monthly trade value for each administrative area in China. 相似文献
16.
V. M. Zolotarev V. V. Uchaikin V. V. Saenko 《Journal of Experimental and Theoretical Physics》1999,88(4):780-787
The superdiffusion equation with a fractional Laplacian Δ
α/2 in N-dimensional space describes the asymptotic (t→∞) behavior of a generalized Poisson process with the range (discontinuity) distribution density ∼|x|−α−1. The solutions of this equation belong to a class of spherically symmetric stable distributions. The main properties of
these solutions are given together with their representations in the form of integrals and series and the results of numerical
calculations. It is shown that allowance for the finite velocity of free particle motion for α>1 merely amounts to a reduction in the diffusion coefficient with the form of the distribution remaining stable. For α<1 the situation changes radically: the expansion velocity of the diffusion packet exceeds the velocity of free particle motion
and the superdiffusion equation becomes physically meaningless.
Zh. éksp. Teor. Fiz. 115, 1411–1425 (April 1999) 相似文献
17.
J. Zhang H. Huang 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(2):247-251
In order to describe the entangled network structure in polymer melts visually, we propose an evolving network model with
community structure. This network model grows according to the inner-community and inter-community preferential mechanisms
of both community sizes and node degrees. Numerical simulation results indicate that the cumulative distribution of community
size and node degree distribution follow power-law distributions P(S≥s)∼s-υ and P(k)∼k-γ respectively, with the exponents of υ≥1 and . 相似文献
18.
S. C. Wang J. J. Tseng C. C. Tai K. H. Lai W. S. Wu S. H. Chen S. P. Li 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(1):105-111
Many systems of different nature exhibit scale free behaviors. Economic
systems with power law distribution in the wealth are one of the examples.
To better understand the working behind the complexity, we undertook an
experiment recording the interactions between market participants.
A Web server was setup to administer the exchange of
futures contracts whose liquidation prices were coupled to event outcomes.
After free registration, participants started trading to compete for
the money prizes upon maturity of the futures contracts at the end of
the experiment. The evolving `cash' flow
network was reconstructed from the transactions between players.
We show that the network topology is hierarchical, disassortative and
small-world with a power law exponent of
1.02±0.09 in the degree distribution after an exponential decay correction.
The small-world property emerged early in the experiment while the number
of participants was still small.
We also show power law-like distributions of the net incomes and
inter-transaction time intervals. Big winners and losers are associated with
high degree, high betweenness centrality,
low clustering coefficient and low degree-correlation. We identify communities
in the network as groups of the like-minded. The distribution of the
community sizes is shown to be power-law distributed with an exponent of
1.19±0.16. 相似文献
19.
S. Carmi Z. Wu E. López S. Havlin H. Eugene Stanley 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(2):165-174
We study the transport properties of model networks such as
scale-free and Erd?s-Rényi networks as well as a real
network. We consider few possibilities for the trnasport problem.
We start by studying the conductance G between two arbitrarily
chosen nodes where each link has the same unit resistance. Our
theoretical analysis for scale-free networks predicts a broad
range of values of G, with a power-law tail distribution
$\Phi_{\rm SF}(G)\sim G^{-g_G}$
, where gG=2λ-1, and
λ is the decay exponent for the scale-free network degree
distribution. The power-law tail in ΦSF(G) leads to
large values of G, thereby significantly improving the transport
in scale-free networks, compared to Erd?s-Rényi networks
where the tail of the conductivity distribution decays
exponentially. We develop a simple physical picture of the
transport to account for the results. The other model for
transport is the max-flow model, where conductance is defined
as the number of link-independent paths between the two nodes, and
find that a similar picture holds. The effects of distance on the
value of conductance are considered for both models, and some
differences emerge. We then extend our study to the case of
multiple sources ans sinks, where the transport is defined between two
groups of nodes. We find a fundamental difference between
the two forms of flow when considering the quality of the
transport with respect to the number of sources, and find an
optimal number of sources, or users, for the max-flow case. A
qualitative (and partially quantitative) explanation is also
given. 相似文献
20.
T. Kaizoji 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):123-127
In this paper, we quantitatively investigate the properties of a statistical ensemble of stock prices. We focus attention
on the relative price defined as X(t) = S(t)/S(0), where S(0), is the stock price for an onset time of the bubble. We selected
approximately 3200 stocks traded on the Japanese Stock Exchange, and formed a statistical ensemble of daily relative prices
for each trading day in the 3-year period from January 4, 1999 to December 28, 2001, corresponding to the period in which
internet Bubble formed and crashed in the Japanese stock market.
We found that the upper tail of the complementary cumulative distribution function of the ensemble of the relative prices
in the high value of the price is well described by a power-law distribution, P(S>x) ∼x-α , with an exponent that moves over time. Furthermore we found that as the power-law exponents α approached two, the bubble burst. It is reasonable to suppose that it indicates that internet bubble is about to burst. 相似文献