bluuebunny/crossref_metadata_2025 huggingface dataset:
POLARIZED PARITY VIOLATING ELECTRON SCATTERING ON 3H AND ITS RELATION TO THE 3He CASE
Authors: MINTZ S. L. , GERSTNER G. M. , BARNETT M. A. , POURKAVIANI M.
Published: April 2003

We calculate the asymmetry parameters, A, and figures-of-merit for polarized parity violating electron scattering from 3 H via the reaction, e- + 3 H → 3 H + e- for incident electron energies of 1.0 GeV, 2.0 GeV, and 4.0 GeV. We find a sharp variation in A due to cancellations between the weak and electromagnetic form factors caused by the different q2 dependences of these form factors. These variations are similar to those found in the asymmetry for the reaction, e- + 3 He → e- + 3 He but occur at different angles due to the difference in form factors for the two cases. We find that at small angles, the asymmetry may be obtained to reasonably high accuracy for all energies considered and that there is a weak minimum in it at small angles for all of the energies considered here. We show that it might be possible to observe strange quark contributions to the asymmetry at this minimum due to the high sensitivity of A to strange quark contributions in this region. In addition we find that the asymmetry and figures of merit are in the range of those for other proposed target nuclei.
THE COLLISIONAL DECAY OF A FERMI SYSTEM INTERACTING WITH A MANY-MODE ELECTROMAGNETIC FIELD
Authors: STEFANESCU E. , SANDULESCU A. , SCHEID W.
Published: April 2003

We consider a system of Z fermions coupled to a dissipative environment through a two-body potential. We represent the system in a basis of single-particle, two-particle, … Z-particle excitated states. Using a procedure for averaging the rapid oscillations of the reduced density matrix in the interaction picture, the master equation of the system takes the form of a series expansion of powers of the dissipative potential matrix elements. The term of the second-order describes single-particle transitions, while the higher-order terms correspond to correlated transitions of the system particles. For the second- and the third-order terms, we derive microscopic expressions of the dissipative coefficients. For dissipative systems, when the state collectivity is broken into pieces through quantum diffusion, we use the quantum master equation of the second-order approximation. This equation satisfies basic physical conditions: particle conservation, Fermi–Dirac or Bose–Einstein distributions as asymptotic solutions of the populations, and entropy increase. On this basis, the decay of a Fermi system interacting with a many-mode electromagnetic field is described in terms of microscopic quantities: the matrix elements of the dissipative potential, the densities of the environment states, and the occupation probabilities of these states. A near-dipode–dipode interaction of the system with other neighbouring systems is taken into account. In addition to the coupling of the polarization with the population, included in the usual equations for two-level systems as a non-linear detuning, in equations for N-level systems two new couplings of the polarizations appear: a coupling due to the proximity potential, and a coupling due to the local field corrections, as a renormalization of the Rabi frequencies.
MACROSCOPIC-MICROSCOPIC ENERGY OF ROTATING NUCLEI IN THE FUSION-LIKE DEFORMATION VALLEY
Authors: GHERGHESCU RADU A. , ROYER GUY
Published: April 2003

The energy of rotating nuclei in the fusion-like deformation valley has been determined within a liquid drop model including the proximity energy, the two-center shell model and the Strutinsky method. The potential barriers of the 84 Zr , 132 Ce , 152 Dy and 192 Hg nuclei have been determined. A first minimum having a microscopic origin and lodging the normally deformed states disappears with increasing angular momenta. The microscopic and macroscopic energies contribute to generate a second minimum where superdeformed states may survive. It becomes progressively the lowest one at intermediate spins. At higher angular momenta, the minimum moves towards the foot of the external fission barrier leading to hyperdeformed quasi-molecular states.
NON-EIKONAL PHASE SHIFT ANALYSIS FOR 12C + 12C ELASTIC SCATTERING
Authors: KIM YONG JOO , CHA MOON HOE
Published: April 2003

We present first-order non-eikonal correction to the eikonal phase shifts for heavy ion elastic scattering based on Coulomb trajectories of colliding nuclei. It has been applied satisfactorily to elastic angular distributions of the 12 C + 12 C system at E lab = 240, 360 and 1016 MeV. The refractive oscillations observed in the elastic scattering angular distributions could be explained due to interference between the near- and far-side amplitudes. The presence of a nuclear rainbow is evidenced through classical deflection function. We have found that the first-order non-eikonal effect on the imaginary potential is important when the absorptive potential is weak and the real potential is strong.
TOTAL ENERGY LOSSES DUE TO THE RADIATION IN AN ACOUSTICALLY BASED UNDULATOR: THE UNDULATOR AND THE CHANNELING RADIATION INCLUDED
Authors: KOROL ANDREI V. , SOLOV'YOV ANDREY V. , GREINER WALTER
Published: April 2003

This paper is devoted to the investigation of the radiation energy losses of an ultra-relativistic charged particle channeling along a crystal plane which is periodically bent by a transverse acoustic wave. In such a system there are two essential mechanisms leading to the photon emission. The first one is the ordinary channeling radiation. This radiation is generated as a result of the transverse oscillatory motion of the particle in the channel. The second one is the acoustically induced radiation. This radiation is emitted because of the periodic bending of the particle's trajectory created by the acoustic wave. The general formalism described in our work is applicable for the calculation of the total radiative losses accounting for the contributions of both radiation mechanisms. We analyze the relative importance of the two mechanisms at various amplitudes and lengths of the acoustic wave and the energy of the projectile particle. We establish the ranges of projectile particle energies, in which total energy loss is small for the LiH, C, Si, Ge, Fe and W crystals. This result is important for the determination of the projectile particle energy region, in which acoustically induced radiation of the undulator type and also the stimulated photon emission can be effectively generated. The latter effects have been described in our previous works.
SURFACE TENSION AT FINITE TEMPERATURE IN THE MIT BAG MODEL
Authors: PARIA LINA , ABBAS AFSAR , MUSTAFA M. G.
Published: April 2003

At T=0 the surface tension σ1/3 in the MIT bag model for a single hadron is known to be negligible as compared to the bag pressure B1/4. We show that at finite temperature it has a substantial value of 50–70 MeV which also differs from hadron to hadron. We also find that the dynamics of the Quark-Gluon Plasma is such that the creation of hybrids [Formula: see text] with massive quarks will predominate over the creation of [Formula: see text] mesons.
THE ROLE OF Δ(1232) IN TWO-PION EXCHANGE THREE-NUCLEON POTENTIAL
Authors: KABIR K. , DATTA T. K. , PERVIN MUSLEMA , NATH L. M.
Published: April 2003

In this paper we have studied the two-pion exchange three-nucleon potential (2πE-3NP) using an approximate SU(2)×SU(2) chiral symmetry of the strong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagrangian are supplemented with contributions from the well-known σ-term and the Δ(1232) exchange. It is the role of the Δ-resonance in 2πE-3NP, which we have investigated in detail in the framework of the Lagrangian field theory. The Δ-contribution is quite appreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds |Z|≤1/2. We find that the Δ-contribution to the important parameters of the 2πE-3NP depends on the choice of a value for Z, although the correction to the binding energy of triton is not expected to be very sensitive to the variation of Z within its bounds.
EFFECTIVE VECTOR MESON MASSES IN A CUTOFF FIELD THEORY
Authors: SAKAMOTO KATSUAKI , NAKAI MANABU , KOUNO HIROAKI , HASEGAWA AKIRA , NAKANO MASAHIRO
Published: April 2003

Based on quantum hadrodynamics with a finite cutoff, the effective masses of vector mesons (ω,ρ) in nuclear medium are calculated. We use a low-energy effective Lagrangian which is obtained by integrating high-energy quantum fluctuations. Although we use an artificial cutoff, the cutoff-dependence can be removed order by order. It is also found that the effective ρ-meson mass [Formula: see text] decreases as the density increases. The rate of the decrease becomes smaller at high density. As a result, at the normal density, [Formula: see text] is 0.85~0.92.
VACUUM DISCHARGE AS A POSSIBLE SOURCE OF GAMMA-RAY BURSTS
Authors: MAO G. , CHIBA S. , GREINER W. , OYAMATSU K.
Published: April 2003

We propose that spontaneous particle–anti-particle pair creations from the discharged vacuum caused by the strong interactions in dense matter are major sources of γ-ray bursts. Two neutron star collisions or black-hole-neutron star mergers at cosmological distance could produce a compact object with its density exceeding the critical density for pair creations. The emitted anti-particles annihilate with corresponding particles at the ambient medium. This releases a large amount of energy. We discuss the spontaneous [Formula: see text] pair creations within two neutron star collision and estimate the exploded energy from [Formula: see text] annihilation processes. The total energy could be around 1051–1053erg depending on the impact parameter of colliding neutron stars. This value fits well into the range of the initial energy of the most energetic γ-ray bursts.
OPTICAL POTENTIALS BY INVERSION FOR 16O ION ELASTIC SCATTERINGS AT Elab=1503 MeV
Authors: KIM YONG JOO , CHA MOON HOE
Published: April 2003

The optical potentials by inversion are presented in two ways. The first one is to use the inverse eikonal relations derived from McIntyre phase shifts. The second one is to solve the inversion problem based on McIntyre parametrization of S-matrix corresponding to the Woods-Saxon type optical potentials. The optical potentials obtained from the two inversion methods are applied to the systems 16 O +12 C , 16 O +28 Si , and 16 O +40 Ca at E lab =1503 MeV . The calculated results are compared with those from the optical model analysis. It is shown that both the two methods lead to reasonable agreements, in the surface region, to the results from the optical model analysis.
EXCEPTIONAL STRUCTURES IN THE ODD-ODD NUCLEUS 250Md
Authors: SOOD P. C. , SAINATH M. , VENKATARAMANIAH K.
Published: April 2003

The low-energy two-quasiparticle bandhead energies for the odd-odd Z=101 nucleus 250 Md are evaluated using a zero range residual neutron-proton interaction. The 250Md ground state is seen to have the spin-parity Iπ=0- corresponding to the singlet band from the configuration {p : 7/2[514]⊗n:7/2[624]} in violation of the Gallagher-Moszkowski (GM) coupling rule. The situation here is shown to be almost identical to that for the rare-earth nucleus 166 Ho , which is the only well-established exception to the GM rule known so far. Analysis of the expected low energy spectrum, including the rotational levels, for 250 Md reveals the occurrence of an as-yet-unobserved long-lived high-spin Iπ = 7- isomeric state around (80±30) keV with dominant ε and α decay modes.
INFLUENCE OF THE LOW-LYING DISCRETE NUCLEAR STATES ON THE PARTITION FUNCTION FOR STELLAR ELECTRON CAPTURE AND BETA DECAY RATES
Authors: DIMARCO ALEJANDRO , DIAS HÉLIO , VELASCO FERMIN GARCIA , LOSANO LAÉRCIO
Published: April 2003

The influence of low-lying discrete states on the partition function for electron capture and beta decay rates in stellar conditions is discussed. Calculations are carried out for 56 Fe , 57 Fe , 59 Co and 60 Co . Experimental data and different level densities are used. We show that by using a simple but consistent approximation to calculate the nuclear partition function, it is possible to modify significantly the electron capture and beta decay rates.
GENERATOR COORDINATE METHOD CALCULATIONS FOR GROUND AND FIRST EXCITED COLLECTIVE STATES IN 4He, 16O AND 40Ca NUCLEI
Authors: IVANOV M. V. , ANTONOV A. N. , GAIDAROV M. K.
Published: April 2003

The main characteristics of the ground and, in particular, the first excited monopole state in the 4 He , 16 O and 40 Ca nuclei are studied within the generator coordinate method using Skyrme-type effective forces and three construction potentials, namely the harmonic-oscillator, the square-well and Woods-Saxon potentials. Calculations of density distributions, radii, nucleon momentum distributions, natural orbitals, occupation numbers and depletions of the Fermi sea, as well as of pair density and momentum distributions are carried out. A comparison of these quantities for both ground and first excited monopole states with the available empirical data and with the results of other theoretical methods are given and discussed in detail.
PHENOMENOLOGICAL POTENTIAL, MODEL WAVEFUNCTION AND DIFFRACTIVE INTERACTION OF THREE-NUCLEON-NUCLEI WITH HEAVY NUCLEI
Authors: KORDA V. YU.
Published: April 2003

On the basis of the simple strict three-body analysis the hyperspherical phenomenological potential and model wavefunction of the three-nucleon ground-state relative motion are built to be permutationally invariant. The analytical expressions for the integrated cross-sections of different three-nucleon-nuclei–nuclei diffraction interaction processes are derived with the new wavefunction presented.
LOW-SPIN STATES OF 83Rb EXCITED IN THE 83Sr(β++EC)83Rb DECAY
Authors: YU XIAOHAN , SHI SHUANGHUI , GU JIAHUI , LIU JINGYI , LI WENXIN , SHEN SHUIFA , LI YAN
Published: April 2003

Gamma-rays from the 83 Sr (β++ EC )83 Rb decay have been investigated with Compton suppressed HpGe detectors. The activity was produced via the 85 Rb (p,3n) reaction at 27.1 MeV beam energy. Singles in multispectra mode and γ–γ coincidence experiments were performed. Approximately 190 transitions including 94 new transitions and 19 new levels were assigned to 83 Rb , based on their measured half-life and/or observation in coincidence with well-known lines. A decay scheme has been constructed consisting of 41 excited states and 180 transitions in 83 Rb . Additional new information has been obtained on γ-ray branching ratios, log ft values, spins and parities.
SEMICLASSICAL QUANTISATION OF PARTICLE-ROTOR MODEL AND ΔI=2 STAGGERING OF SUPERDEFORMED BANDS
Authors: MALIK SHAM SUNDER , DUDEJA MANISHA , AMITA  , JAIN ASHOK KUMAR , AHMED ZAFAR
Published: April 2003

A detailed numerical analysis of the semi-classical dynamics of single-j particle rotor model in the nonlinear regime is carried out. The ensuing numerical results exhibit similarities with many features of the superdeformed bands. In particular a ΔI=2 staggering is obtained and is attributed to the tunneling in the double-well potential of j3.
ALPHA-NUCLEUS TOTAL REACTION CROSS SECTION IN THE RIGID PROJECTILE MODEL USING MICROSCOPIC N-α AMPLITUDE
Authors: AHMAD I. , ABDULMOMEN M. A. , AL-KHATTABI L. A.
Published: April 2003

Coulomb modified Glauber model has been applied to calculate α total reaction cross-section for 12 C , 16 O and 40 Ca nuclei in the rigid projectile model using microscopic N-α amplitude which is evaluated in terms of NN scattering amplitude parameters. Using realistic densities for target nuclei and the same input information, we find that the predictions of the rigid projectile approximation for α reaction cross sections are, in general, in better agreement with the experimental data than those of the optical limit approximation.
CHARACTERISTICS OF RELATIVISTIC CHARGED PARTICLES PRODUCED IN 24Mg–EMULSION INTERACTIONS AT 4.5A GeV/C
Authors: ALLAH N. N. ABD , ABOU-STEIT S. A. H. , MOHERY M. , ABDEL-AZIZ S. S.
Published: April 2003

The interactions of 4.5A GeV/c 24 Mg nuclei with emulsion have been studied. The multiplicity distributions of all the produced target protons from 24 Mg –emulsion interactions has been found to obey the KNO scaling behavior. The angular characteristics of the relativistic charged particles have been investigated and their dependence on the multiplicity of the relativistic shower particles has been studied. The results reveal that increasing the multiplicity of the shower particles, leads to a shift of the peak of the pseudorapidity distributions towards the lower values of the pseudorapidity and also to a decrease of the average pseudorapidity. The study of the rapidity dispersion of the relativistic charged particles shows that the clusterization effect is significant among the final state of the relativistic particles produced in the heavy-ion interactions. Azimuthal correlations in the angles of the relativistic charged particles have been investigated.
SEPARATION OF ROTATIONAL DEGREES OF FREEDOM IN A QUANTUM THREE-BODY PROBLEM
Authors: GU XIAO-YAN , DUAN BIN , MA ZHONG-QI
Published: April 2003

We demonstrate explicitly how the rotational degrees of freedom in a quantum three-body problem is separated completely from the internal ones. It is shown that only finite partial angular momentum states are involved in constructing the base-functions with the given angular momentum and parity, and the contributions by the remaining partial angular momentum states are incorporated into the contributions by the generalized radial functions.
A STOCHASTIC MODEL FOR EPIDEMICS BASED ON THE RENEWAL EQUATION
Authors: GIELEN J. L. W.
Published: April 2003

A stochastic continuous-infection model is developed that describes the evolution of an infectious disease introduced into an infinite population of susceptibles. The proposed model is the natural stochastic counterpart of the deterministic model for epidemics, based on the renewal equation. As in the deterministic model, the infectivity of an infected individual is a function of his age-of-infection, that is the time elapsed since his own infection. A time-dependent external source of infection is included. The model provides analytical expressions that describe the stochastic infective-age structure of the population at any moment of time. It is shown that the mean value of the number of infectives predicted by the stochastic model satisfies the renewal equation, which furnishes a formal solution of this equation. The model also yields simple expressions for the expected arrival times of infectives, that can be useful for the inverse problem. An explicit expression for the final size distribution is obtained. This leads to a precise quantitative threshold theorem that distinguishes between the possibilities of a minor outbreak or a major build-up of the epidemic.
POSSIBLE OSCILLATORY BEHAVIOR IN P53–MDM2 INTERACTION COMPUTER SIMULATION
Authors: MIHALAS G. I. , SIMON Z. , BALEA G. , POPA E.
Published: April 2003

Specific activator and repressor transcription factors, which bind to specific regulator DNA sequences, play an important role in gene activity control. Interactions between genes coding such transcription factors should explain the different stable or, sometimes, oscillatory gene activities characteristic for different tissues. A set of models has been built for several systems with interconnected genes and the results of the simulations performed for the p53–mdm2 are here presented and discussed.
STRUCTURED STOCHASTIC MODELING OF THE PROGRESSION OF RADIATION INDUCED CELLS THROUGH THEIR CYCLES
Authors: RANGAN A. , ARUNACHALAM V.
Published: April 2003

This paper presents a new stochastic model to describe the progression of cells subject to radiation damage, through their cell cycles. The expected number of cells in various phases in the transient and steady state are obtained. Several interesting cases like quiescence in tumor cell population, effects of split dose and holding time on cell survival are also discussed using the developed model. The phase structured model offers quiescence and variable cell cycle time as contributing factors for the retardation of cell growth and the ultimate cell population reaching a steady state.
THE INFECTION-ENCAPSULATION MODEL — APPLICATION TO DROSOPHILA SIMULANS AND LEPTOPILINA BOULARDI STRAINS FROM TUNISIA
Authors: ROUAULT JACQUES
Published: April 2003

Some larvae of Drosophila infected by parasitic wasps are able to encapsulate the larvae of the parasitoid, and the emerging hosts present a visible melanized capsule in the abdomen. In this paper, a model for estimating the infection rate RI by the rate of hosts presenting a capsule HC is developed. For Drosophila simulans parasitized by Leptopilina boulardi, the model RI = HC/(k+(1-k)HC), with k=0.123, is validated from experimental data. The validation process is based upon a bootstrap strategy over 12870 possibilities of grouping 8 elementary experimental results among 16. Validation consists in fitting the theoretical curve from a data set and in controlling the overlap of the curve with the confidence rectangle established with the complementary data set. This validation process appears to be independent of the confidence level. This infection-encapsulation model is applied to field observations in Tunisia and predicts high levels of infection. This prediction is confirmed at Nasr'Allah by a direct measure of the infection rate. The biological hypotheses involved in this model are discussed. The model merely allows one to follow the evolution of infection in population cages and in the wild, by catching and counting adult hosts, without access to breeding sites. The model is generalisable to other species of hosts and parasitoids presenting the encapsulation reaction.
MARKOV SEMIGROUPS AND STABILITY OF THE CELL MATURITY DISTRIBUTION
Authors: RUDNICKI RYSZARD , PICHÓR KATARZYNA
Published: April 2003

A model of the maturity-structured cell population is considered. This model is described by a partial differential equation with a transformed argument. Using the theory of Markov semigroups we establish a new criterion for asymptotic stability of such equations.
ASYMPTOTIC DISTRIBUTION OF THE ESTIMATED BDS STATISTIC AND RESIDUAL ANALYSIS OF AR MODELS ON THE CANADIAN LYNX DATA
Authors: LAI DEJIAN
Published: April 2003

The Brock–Dechert–Scheinkman (BDS) statistic is a nonparametric statistic based on correlation integral for testing independence. It has a special ability to identify dependence in a given time series generated by some simple dynamic systems when many conventional test statistics are not able to distinguish this type of time series from observations of independent, identically distributed (IID) random variables. Using the contiguity property derived from the local asymptotic normality for the log-likelihood ratio of nonlinear autoregressive processes, we prove the central limit theorem for the estimated BDS statistic on the residuals of fitting nonlinear autoregressive models. Comparative studies on the BDS statistic and some other nonparametric statistics on simulated time series and residuals from the AR models on the Canadian lynx are also provided in this paper.
REST QUANTIFIED BY A FRACTAL DIMENSION OF MOVEMENT EVENTS: A BIOMEDICAL APPLICATION OF INTERMITTENCY ESTIMATION
Authors: BICKEL DAVID R.
Published: April 2003

The intermittency of a time-series, i.e. the extent to which it departs from slowly-varying, unifractal dynamics, can often be quantified by simple scale-free statistics. For fractal point processes, singular measures, and certain other models that describe physical and biological phenomena, the correlation co-dimension, C2, quantifies intermittency. C2 of human activity during the night quantifies restfulness in that it is negatively correlated with the average activity level. However, C2 of activity appears to be more sensitive to the use of steroids than the average activity level.
FRACTALS IN CELLULAR SYSTEMS AS SOLUTIONS FOR COGNITIVE PROBLEMS
Authors: VAN LOOCKE PHILIP
Published: April 2003

A cellular method for the solution of function approximation and classification problems is introduced. It solves problems of the type solved by connectionist networks, but has an advantage of visualization. Solutions of complex, high-dimensional and non-linear problems correspond to sets of units that define fractal, two-dimensional patterns of aesthetic attractiveness. These sets, in turn, can be considered as patterns, and stored with a classic connectionist learning rule in a network. Then, one obtains a network in which the memorized patterns correspond to meta-patterns in the sense that they correspond to mappings between input and output patterns.
FRACTAL CANTOR PATTERNS IN THE SEQUENCE STRUCTURE OF DNA
Authors: PROVATA A. , ALMIRANTIS Y.
Published: April 2003

The coding parts of DNA sequences are regarded as clusters of connected sites of a random Cantor-like set, while the non-coding parts are regarded as the empty regions of the same set. Under this representation, we find that higher eucaryotes are mapped on random Cantor sets with fractal dimension around 0.85, while lower organisms are mapped on Cantor sets with fractal dimension 1. This result indicates that the coding/non-coding partition in the DNA sequences of lower organisms is homogeneous-like, while in the higher eucaryotes the partition is fractal. This result agrees with the power law distribution observed in the non-coding parts of higher eucaryotes.
EVIDENCE FOR A FRACTAL STOCHASTIC PROCESS UNDERLYING MEASLES EPIDEMICS IN BRITAIN
Authors: KENDAL WAYNE S.
Published: April 2003

The variability in measles incidence during the pre-vaccination period of 1944 to 1966, as recorded from 366 communities in England and Wales, was examined for properties of fractal stochastic processes. The power spectral density, Fano factor, and Allan factor were computed from the incidence time-series, and all revealed power-law scaling. As well, the distribution histogram for the weekly incidence approximated a geometric distribution. These features constituted evidence for a fractal stochastic process with underlying geometric statistics at play in the development and resolution of measles epidemics.
FRACTAL BLOCK-MATCHING IN MOTION-COMPENSATED VIDEO CODING
Authors: HUFNAGL CH. , UHL A.
Published: April 2003

In this work, we propose and investigate techniques developed in the context of fractal image coding for generalizing block-matching algorithms as used in motion-compensated video codecs. By allowing a gray value adaptation (similar to non-iterative fractal techniques) within the block-matching process, we obtain MC error residuals with significantly lower entropy values as compared to pure block-matching. This leads to a significantly improved rate/distortion performance for video sequences with illumination changes or high motion content at a low computational cost.
THE FINITE-DIFFERENCE METHOD OF ONE-DIMENSIONAL NONLINEAR SYSTEMS ANALYSIS
Authors: YU. SHAHVERDIAN A.
Published: April 2003

The paper introduces one-dimensional analogy of Poincare "section" method. It reduces the one-dimensional nonlinear system orbit's study to consideration of some special conjugate orbit's "asymptotical" intersections with a thin arithmetical space of zero Lebesgue measure. The application of this approach to analysis of the logistic map orbits, earthquake time-series, and the sequences of fractional parts, is considered. Through computational study of these time-series, the existence of some Cantor sets, to which the conjugate orbits are attracted, is established. A fractal dynamical system, describing these different systems from a unified point of view, is introduced. The inner differential Cantorian structure of brain activity and time flow is discussed.
EXPERIMENTAL VERIFICATION FOR FRACTAL TRANSITION USING A FORCED DAMPED OSCILLATOR
Authors: GOHARA KAZUTOSHI , SAKURAI HIROSHI , SATO SHOZO
Published: April 2003

A damped oscillator stochastically driven by temporal forces is experimentally investigated. The dynamics is characterized by a set Γ(C) of trajectories in a cylindrical space, where C is a set of initial states on the Poincaré section. Two sets, Γ(C) and C, are attractive and unique invariant fractal sets that approximately satisfy specific equations derived previously by the authors. The correlation dimension of the set C is in good agreement with the similarity dimension obtained for a strictly self-similar set constructed by contraction mappings while C is a self-affine set constructed by non-contraction mappings.
POWER LAWS, WEAK lpESTIMATE AND WAVELET DE-NOISING
Authors: MATSUOKA TOMOHIRO , UENO TOSHIHIDE , ADACHI TAKASHI , OKADA MASAMI
Published: April 2003

Data with power law distributions are studied by a scaling argument. Then related weak lpsequences are characterized. As an application we can show in a transparent way that the wavelet de-noising theory holds under a mild assumption which is given by means of weak lp(quasi-)norms.
HOW TO USE FRACTAL DIMENSIONS TO QUALIFY WRITINGS AND WRITERS
Authors: VINCENT NICOLE , BOULETREAU VIVIANE , EMPTOZ HUBERT , SABOURIN ROBERT
Published: April 2003

Handwriting is a very special material as it is both a copy of a model as well as the result of very complex biological mechanisms. We have explored the domain showing the interest of a study relying on fractal principle. We attempt to justify the fractal behavior and fractal approach used here, and introduce some applications of our study in the medical field and in the field of handwriting recognition or authentication. Four new parameters are defined and experimented.
CAPM, RISK AND PORTFOLIO SELECTION IN "α-STABLE MARKETS"
Authors: BELKACEM LOTFI , VÉHEL JACQUES LÉVY , WALTER CHRISTIAN
Published: April 2003

Our main purpose in this paper is to derive the generalized equilibrium relationship between risk and return under the assumption that the asset returns follow a joint symmetric α-stable distribution, with 1<α<2. In order to justify such an investigation, we start by empirically evidencing the fractal structure of stocks market through extensive tests of self-similarity and stability. These tests allow us to model price changes with α-stable distributions. We then show that equilibrium rates of return on all risky assets are functions of their covariation with the market portfolio. The "stable" CAPM highlights a new measure of the quantity of risk which may be interpreted as a generalized beta coefficient.
DIFFUSION EQUATION FOR DISORDERED FRACTAL MEDIA
Authors: ZENG QIUHUA , LI HOUQIANG
Published: April 2003

The movement of the fractal Brownian particle in isotropic and homogeneous two-dimensional assembling fractal spaces is studied by the standard diffusion equation on fractals, and we find that particle movement belongs to the anomalous diffusion. At the same time, by discussing the defectiveness of earlier proposed equations, a general form of analytic fractional diffusion equation is proposed for description of probability density of particles diffusing on fractal geometry at fractal time, and the solution connects with the ordinary solutions in the normal space time limit.
STATISTICAL AND FRACTAL ANALYSIS OF CHINESE EARTHQUAKE TIME SERIES
Authors: LAI DEJIAN
Published: April 2003

In this study, we report statistical and fractal analysis on the time series of the earthquake records of China. Our results show that the Korcak exponents for the time series of Chinese earthquakes are different from the Japanese earthquake time series.
ON THE APPLICATION OF METHODS USED TO CALCULATE THE FRACTAL DIMENSION OF FRACTURE SURFACES
Authors: BABADAGLI TAYFUN , DEVELI KAYHAN
Published: April 2003

This paper presents an evaluation of the methods applied to calculate the fractal dimension of fracture surfaces. Variogram (applicable to 1D self-affine sets) and power spectral density analyses (applicable to 2D self-affine sets) are selected to calculate the fractal dimension of synthetic 2D data sets generated using fractional Brownian motion (fBm). Then, the calculated values are compared with the actual fractal dimensions assigned in the generation of the synthetic surfaces. The main factor considered is the size of the 2D data set (number of data points). The critical sample size that yields the best agreement between the calculated and actual values is defined for each method. Limitations and the proper use of each method are clarified after an extensive analysis. The two methods are also applied to synthetically and naturally developed fracture surfaces of different types of rocks. The methods yield inconsistent fractal dimensions for natural fracture surfaces and the reasons of this are discussed. The anisotropic feature of fractal dimension that may lead to a correlation of fracturing mechanism and multifractality of the fracture surfaces is also addressed.
FRACTAL DIMENSION FOR A CANCER INVASION MODEL
Authors: AHAMMER H. , DEVANEY T. T. J. , TRITTHART H. A.
Published: April 2003

A long-established investigation method for in vitro cancer invasion using cancer cell spheroid and normal cell spheroid confrontation for the quantitative determination of invasion was expanded to make use of fractal methods. The box-counting method, the sausage method and a local method were used in comparison with image pre-processing steps such as median filtering, closing and opening, or hole filling and scrapping, and artificially added noise images. It was possible to examine the potential role of the fractal capacity dimension for this invasion model. Several aspects such as the absolute value and variance of the different methods were taken into account and compared to well established quantitative parameters. The fractal approach led to very promising results which improved the determination and examination of the invasion process of cancer.
REVEALING LOCAL VARIABILITY PROPERTIES OF HUMAN HEARTBEAT INTERVALS WITH THE LOCAL EFFECTIVE HÖLDER EXPONENT
Authors: STRUZIK ZBIGNIEW R.
Published: April 2003

The local effective Hölder exponent has been applied to evaluate the variability of heart rate locally at an arbitrary position (time) and resolution (scale). The local effective Hölder exponent1,2 used is effectively insensitive to local polynomial trends in heartbeat rate due to the use of the Wavelet Transform Modulus Maxima (WTMM) technique. Also the variability so obtained is compatible in the sense of distribution to the multifractal spectra of the analyzed heart rate time series. This provides the possibility of standardizing the variability estimation for comparison between different patients and between different recordings for one patient. The previously reported global correlation behavior3 is captured in the effective Hölder exponent-based, local variability estimate. This includes discriminating healthy and sick (congestive heart failure patients) on the basis of both the central (Hurst) exponent and the width of the multifractal spectra. In addition to this, we observed intriguing patterns of individual response in variability records to daily activities. A moving average filtering of Hölder exponent-based variability estimates was used to enhance these fluctuations. We find that this way of local presentation of scaling properties may be of clinical importance.
DETERMINATION OF EXPANSIVE SOIL STRENGTH USING A FRACTAL MODEL
Authors: XU YONGFU , SUN DE'AN
Published: April 2003

The micropore surface fractal model for expansive soils is proposed in this paper. Based on the results of the mercury intrusion tests, it is found that the micropore surface fractal dimension is 2.40 for the soil sample with the dry density of 1.50 g/cm 3, and is 2.47 for the soil sample with the dry density of 1.60 g/cm 3. By using the micropore surface fractal model, the shear strength formula for expansive soils is obtained. All the parameters in the proposed shear strength formula are constant, and are independent of matric suction. The validation of the proposed shear strength formula is proven by the results of the triaxial compression tests on an expansive soil taken from Ningxia, China.
THE THERMODYNAMICS OF SOCIAL PROCESSES: THE TEEN BIRTH PHENOMENON
Authors: SCAFETTA NICOLA , HAMILTON PATTI , GRIGOLINI PAOLO
Published: April 2003

We argue that a process of social interest is a balance of order and randomness, thereby producing a departure from a stationary diffusion process. The strength of this departure effect vanishes if the order to randomness intensity ratio vanishes, and this property allows us to reveal, although in an indirect way, the existence of a finite order to randomness intensity ratio. We aim at detecting this effect. We introduce a method of statistical analysis alternative to the compression procedures, with which the limitations of the traditional Kolmogorov-Sinai (KS) approach are bypassed. We prove that this method makes it possible for us to build up a memory detector, which signals the presence of even very weak memory, provided that this is persistent over large time intervals. We apply the analysis to the study of the teen birth phenomenon and we find that the unmarried teen births are a manifestation of a social process with a memory more intense than that of the married teens. We attempt to give a social interpretation of this effect.
DEPENDENCE STRUCTURE OF A RENEWAL-REWARD PROCESS WITH INFINITE VARIANCE
Authors: LEVY JOSHUA B. , TAQQU MURAD S.
Published: April 2003

The on-off renewal-reward process used to explain long-range dependence in Ethernet traffic can be extended to the case where, not only the inter-renewal times but also the rewards have infinite variance. The covariation and the codifference, which generalize the covariance to the infinite variance case, are computed for the limiting process. It is shown that they decay like a power function. The exponent of that power is the same as for fractional stable noise, even though the increments of the limiting process are different from fractional stable noise.
A FRACTAL APPROXIMATION OF CURVES
Authors: GUÉRIN ERIC , TOSAN ERIC , BASKURT ATILLA
Published: April 2003

This paper deals with the approximation of rough curves using a fractal model. The approximation criterion is based on a curve parametrization and the fractal model is a projected iterated function system (IFS) model. This model unifies the IFS model and a classical model used in computer graphics (free form representation with control points). To formulate the approximation problem, we introduce a family of curves based on our model. Then, the approximation problem has a nonlinear fitting formulation. We have tested this fractal approximation method on both smooth and rough synthetic curves. A shape extracted from a natural scene has also been approximated. The obtained results are very satisfying from both quantitative and visual point of view.
ON CONTINUOUSLY-GENERATED SELF-SIMILAR MULTIFRACTALS
Authors: HUILLET THIERRY , PORZIO ANNA
Published: April 2003

An extended class of "continuously-generated and deterministic" multifractals with some features common to the ones of "random" multifractals is investigated.
SELF-SIMILAR MODELS AND SIZE EFFECT OF MULTIPLE FRACTURE
Authors: BORODICH FEODOR M.
Published: April 2003

Multiple fracture of polyphase quasi-brittle materials is analyzed from the standpoint of similarity methods. First, two self-similar models of development of a cloud of micro- and mesocracks in an unbounded solid are constructed. Both presented models supposed that the main part of the process zone is wedge-shaped and the process zone is bounded by an arc of a circle with the center at the main crack tip. The former model is based on the hypothesis of discontinuous self-similar character of the main crack propagation, while the latter model employs physical fractal approach. Finally, the problem of size effect for bounded models is studied. It is assumed that the main cause of the size effect is that the process zone cannot be fully developed in a bounded model of a real size construction.
COMPOSED ACCELERATED ESCAPE TIME ALGORITHM TO CONSTRUCT THE GENERAL MANDELBROT SETS
Authors: LIU XIANGDONG , ZHU ZHILIANG , WANG GUANGXING , ZHU WEIYONG
Published: April 2003

In this paper, we present a new composed accelerated escape time algorithm by introducing a new composed iterative function. By the new algorithm, the points in the general Mandelbrot set can be decided rapidly with the same precision of the origin escape time algorithm.
FRACTAL METHODS APPLIED TO DESCRIBE CELLULAR AUTOMATON COMBAT MODELS
Authors: LAUREN MICHAEL K.
Published: April 2003

Analysis of warfare data provides compelling evidence that intensity of conflicts obeys a power-law (fractal) dependence on frequency. There is also evidence for the existence of other power-law dependences and traits characteristic of high-dimensional chaotic systems, such as fat-tailed probability distributions and intermittency in warfare data. In this report, it is discussed how a cellular automaton model used to describe modern maneuver warfare produces casualty distributions which exhibit these properties. This points to a possible origin of the characteristics of the larger timescale data. More interesting, the techniques of fractal analysis offer a method by which to characterize these behaviors, and to quantify the difference between models based on complexity theory (such as cellular automata models), and more traditional combat models based on the physics of military equipment.
FRACTAL CHARACTERS OF PORE MICROSTRUCTURES OF TEXTILE FABRICS
Authors: YU BOMING , LEE L. JAMES , CAO HANQIANG
Published: April 2003

It is found that the pore microstructures of textile fabrics, widely used in the manufacture of fiber-reinforced composites, exhibit the fractal characters. The fractal behaviors are described by the proposed analytical method and measured by the box-counting method for the three different types of textile fabrics: plain woven, four-harness, bidirectional-stitched fiberglass mats. The pore area fractal dimension is derived analytically and found to be the function of the porosity and architectural parameters of fabrics. The results indicate that the fractal characters are isotropic although the fabrics are rothotropic in structures. The theoretical predictions by the proposed analytical model are in good agreement with those from the box-counting method, and this verifies the proposed fractal dimension model. The present fractal analysis may have the potential and significance on fractal analysis of transport properties (such as the permeability, dispersion, thermal and mechanical properties) in porous media.
IODINE FRACTALS IN ION CONDUCTING POLYMER MATRIX
Authors: CHANDRA AMITA
Published: April 2003

Large size diffusion limited aggregates (DLA) in ion conducting polymeric system, PEO:NH 4 I (+ Al 2 O 3), have been obtained. The species responsible for the formation of the DLA have been identified as [Formula: see text] by fluorescence studies. It is also shown that if I 2 gets formed (instead of [Formula: see text] aggregates) at selected regions, then "strain field" is established which forbids further approach of ionic random walkers and hence no fractals grow around these regions.
CONSTRUCTING MULTIPLE WAVELET PACKETS WITH FIFS
Authors: CHEN GANG , FENG ZHIGANG
Published: April 2003

By using fractal interpolation functions (FIF), a family of multiple wavelet packets is constructed in this paper. The first part of the paper deals with the equidistant fractal interpolation on interval [0, 1]; next, the proof that scaling functions ϕ1, ϕ2,…,ϕr constructed with FIF can generate a multiresolution analysis of L2(R) is shown; finally, the direct wavelet and wavelet packet decomposition in L2(R) are given.
UPPER-TRUNCATED POWER LAW DISTRIBUTIONS
Authors: BURROUGHS STEPHEN M. , TEBBENS SARAH F.
Published: April 2003

Power law cumulative number-size distributions are widely used to describe the scaling properties of data sets and to establish scale invariance. We derive the relationships between the scaling exponents of non-cumulative and cumulative number-size distributions for linearly binned and logarithmically binned data. Cumulative number-size distributions for data sets of many natural phenomena exhibit a "fall-off" from a power law at the largest object sizes. Previous work has often either ignored the fall-off region or described this region with a different function. We demonstrate that when a data set is abruptly truncated at large object size, fall-off from a power law is expected for the cumulative distribution. Functions to describe this fall-off are derived for both linearly and logarithmically binned data. These functions lead to a generalized function, the upper-truncated power law, that is independent of binning method. Fitting the upper-truncated power law to a cumulative number-size distribution determines the parameters of the power law, thus providing the scaling exponent of the data. Unlike previous approaches that employ alternate functions to describe the fall-off region, an upper-truncated power law describes the data set, including the fall-off, with a single function.
GROWTH AND LINKAGE OF CRACKS AND FORMATION OF CREEP FRACTURE PATTERN SIMULATED BY A MULTICRACK GROWTH MODEL
Authors: TANAKA MANABU , KATO RYUICHI , KAYAMA ATSUSHI
Published: April 2003

A computer simulation using a multicrack growth model was carried out on the growth and linkage of cracks and the formation of creep fracture pattern resulting from the initial defects. The percolated crack patterns and the number of steps to percolation were examined by Monte Carlo simulation on a square lattice. Effects of stress and grain size on creep fracture process are then discussed. The stress and grain size dependence of the number of steps to percolation in the simulation was similar to that of grain-boundary sliding in the austenitic 21Cr-4Ni-9Mn heat-resisting steel, which controlled the growth of grain-boundary cracks. The fractal dimension of the percolation crack was also correlated with that of the creep fracture pattern in the 21Cr-4Ni-9Mn steel.
STRUCTURE OF THE CUBIC MAPPINGS
Authors: LIAW SY-SANG
Published: April 2003

The parameter and dynamic spaces of the cubic mappings consist of many small copies of the Mandelbrot-like sets and Julia sets, respectively of the standard quadratic mapping z - > z * z + c. We find the effective quadratic mappings for the kth iteration of the cubic mappings in the neighborhood of the centers of these small copies. Thus we are able to calculate the positions, sizes and orientations of these small copies. The structure of the cubic mappings is therefore understood.
DISCLIKE LATTICE REPTILES INDUCED BY EXACT POLYOMINOES
Authors: SONG HYUN JONG , KANG BYUNG SIK
Published: April 2003

In this paper, we show how to derive disclike reptiles from exact polyominoes. For classification of disclike reptiles, we introduce a concept of the state graph. Finally, we exhibit 29 four-piece disclike reptiles derived from tetrominoes.
SPATIAL AND TEMPORAL BEHAVIOR OF CONGESTION IN INTERNET TRAFFIC
Authors: FUKUDA KENSUKE , TAKAYASU HIDEKI , TAKAYASU MISAKO
Published: April 2003

We have developed an approach which allows the determination of relative congestion levels on nodes of TCP/IP computer network by observing test packet round trip time sequences for a series of routers located along the same path. We have also demonstrated the existence of strong spatial correlation of congestion levels. Propagation of congestion between neighboring routers can be observed directly. With increasing network load, distribution of congestion duration times changes from exponential to a distribution falling off slower than power law, via power law distribution. We thus conclude that direct observations of network congestion agree with predictions of a model based on contact process.