bluuebunny/crossref_metadata_2025 huggingface dataset:
PARALLEL RANGE MINIMA ON COARSE GRAINED MULTICOMPUTERS
Authors: MONGELLI H. , SONG S. W.
Published: July 2002

Given an array of n real numbers A=(a0, a1, …, an-1), define MIN(i,j)= min {ai,…,aj}. The range minima problem consists of preprocessing array A such that queries MIN(i,j), for any 0≤i≤n-1 can be answered in constant time. Range minima is a basic problem that appears in many other important graph problems such as lowest common ancestor, Euler tour, etc. In this work we present a parallel algorithm under the CGM model (coarse grained multicomputer), that solves the range minima problem in O(n/p) time and constant number of communication rounds. The communication overhead involves the transmission of p numbers (independent of n). We show promising experimental results with speedup curves approximating the optimal for large n.
DETERMINISTIC BRANCH-AND-BOUND ON DISTRIBUTED MEMORY MACHINES
Authors: HERLEY KIERAN T. , PIETRACAPRINA ANDREA , PUCCI GEPPINO
Published: July 2002

The branch-and-bound problem involves determining the leaf of minimum cost in a cost-labelled, heap-ordered tree, subject to the constraint that only the root is known initially and that the children of a node are revealed only by visiting their parent. We present the first efficient deterministic algorithm to solve the branch-and-bound problem for a tree T of constant degree on a p-procesor distributed-memory Optically Connected Parallel Computer (OCPC). Let c* be the cost of the minimum-cost leaf in T, and let n and h be the number of nodes and the height, respectively, of the subtree T*⊆T of nodes with cost at most c*. When according for both computation and communication costs, our algorithm runs in time O(n/p+h( max {p, log n log p})2) for general values of n, and can be made to run in time O((n/p+h log 4p) log log p) for n polynomial in p. For large ranges of the relevant parameters, our algorithm is provably optimal and improves asymptotically upon the well-known randomized strategy by Karp and Zhang.
GAUSS–MANIN SYSTEM AND THE VIRTUAL STRUCTURE CONSTANTS
Authors: JINZENJI MASAO
Published: July 2002

In this paper, we discuss some applications of Givental's differential equations to enumerative problems on rational curves in projective hypersurfaces. Using this method, we prove some of the conjectures on the structure constants of quantum cohomology of projective hypersurfaces, proposed in our previous article. Moreover, we clarify the correspondence between the virtual structure constants and Givental's differential equations when the projective hypersurface is Calabi–Yau or general type.
ON EIGENVALUE ESTIMATES FOR THE SUBMANIFOLD DIRAC OPERATOR
Authors: GINOUX NICOLAS , MOREL BERTRAND
Published: July 2002

We give lower bounds for the eigenvalues of the submanifold Dirac operator in terms of intrinsic and extrinsic curvature expressions. We also show that the limiting cases give rise to a class of spinor fields generalizing that of Killing spinors. We conclude by translating these results in terms of intrinsic twisted Dirac operators.
A SPIN MODEL OF MARKET DYNAMICS WITH RANDOM NEAREST NEIGHBOR COUPLING
Authors: YAMANO TAKUYA
Published: July 2002

We consider a variant of the so-called Bornholdt spin model of a market dynamics, in which the random couplings with neighbors are incorporated. We observe that the occurrence of high returns decreases with a power law as the number of market participants becomes large up to three dimension.
BOUND CHARGE MOVING IN A MAGNETIC FIELD IN A SPACE WITH A TOPOLOGICAL DEFECT
Authors: AZEVEDO SÉRGIO
Published: July 2002

In this work, using a description of defects in solids in terms of three-dimensional gravity, we have obtained the changes on the spectrum energy and eigenfunctions of a bound particle, moving in a magnetic field, in a space with a linear topological defect, namely disclination and screw dislocation. We find exact expressions for the energy eigenvalue and eigenfunctions and compare these results with the ones obtained in the previous cases.
STABILIZATION AND RADION IN de SITTER BRANE-WORLD
Authors: NOJIRI SHIN'ICHI , ODINTSOV SERGEI D. , SUGAMOTO AKIO
Published: July 2002

We consider the stabilization of de Sitter brane-world. The scalar field bulk-brane theory produces the nontrivial minimum of modulus potential where temporal radion is realized. The hierarchy problem (between Planck and electroweak scales) may be solved. However, the interpretation of radion is not so clear as in AdS brane-world. In particular, the introduction of two times physics or pair-creation of bulk spaces or identification of one of spatial coordinates with imaginary time (nonzero temperature) may be required.
THE DEUTERON STRIPPING ANOMALY AT THRESHOLD OF ANALOGUE CHANNEL AND THE 3 - p WAVE NEUTRON STRENGTH FUNCTION
Authors: COMISEL HORIA , HATEGAN CORNEL
Published: July 2002

We prove in this paper that the magnitude of anomaly in deuteron stripping reactions on A ≈ 80–110 mass target nuclei, at threshold of analogue channel, is proportional to the 3 - p wave neutron strength function. The result is obtained from analysis, within an empirical approach and computational frameworks, of the cross-section and analyzing power experimental data related to this (d,p) anomaly.
MELOSH CONSTRUCTION OF RELATIVISTIC THREE-QUARK BARYON WAVE FUNCTIONS
Authors: SUN XUEPENG , WEBER H. J.
Published: July 2002

A method for constructing a complete set of relativistic three-quark states in light front dynamics is implemented for the nucleon, N*(1520) and N*(1535). This approach facilitates constructing states containing virtual antiquarks and a physical interpretation is provided in terms of transition amplitudes from quark to quark–gluon or quark–Goldstone boson Fock states of chiral dynamics generated by flux tube breaking expected in QCD at intermediate distances.
OBSERVATIONS ON A U(1) × U(1) VECTOR THEORY
Authors: MCKEON D. G. C.
Published: July 2002

The symmetry between two sectors of a model containing two U(1) vector fields (related by a constraint condition) and two conserved currents is examined. The equations of motion for the vector fields, once the constraint condition is applied, is similar in form to the Maxwell equations in the presence of both electric and magnetic charge. The Dirac quantization condition need not be applied. The propagators for the vector fields are computed in a covariant gauge, demonstrating that the model is unitary and renormalizable. A supersymmetric version of the model is presented.
SPIN DISTRIBUTIONS FOR BIPARTITE QUANTUM SYSTEMS
Authors: USHA DEVI A. R.
Published: July 2002

We carryout a comparative study of spin distributions defined over the sphere for bipartite quantum spin assemblies. We analyze Einstein–Podolsky–Rosen–Bohm (EPRB) spin correlations in a spin-s singlet state using these distributions. We observe that in the classical limit of s → ∞, EPRB spin distributions turn out to be delta functions, thus reflecting the perfect anticorrelation property of two-spin vectors associated with a spin-s singlet state.
SUPERSYMMETRIC YANG–MILLS THEORY ON THE LATTICE
Authors: MONTVAY I.
Published: July 2002

Recent development in numerical simulations of supersymmetric Yang–Mills (SYM) theories on the lattice is reviewed.
A MONTE CARLO SIMULATION OF THE COSMIC RAYS INTERACTIONS WITH THE EARTH'S ATMOSPHERE
Authors: ZUCCON P.
Published: July 2002

Substantial fluxes of protons and leptons with energies below the geomagnetic cutoff have been measured by the AMS experiment at altitudes of 370-390 Km, in the latitude interval ±51.7°. The production mechanisms of the observed trapped fluxes are investigated in detail by means of the FLUKA Monte Carlo simulation code. All known processes involved in the interaction of the cosmic protons with the atmosphere (detailed descriptions of the magnetic field atmospheric density, as well as the electromagnetic and nuclear interaction processes) are included in the simulation. The results are presented and compared with the experimental data, indicating good agreement with the observed fluxes. The impact of secondary proton flux on particle production in atmosphere is briefly discussed.
AN ANALYTICAL SOLUTION OF THE COSMIC RAYS TRANSPORT EQUATION IN THE PRESENCE OF THE GEOMAGNETIC FIELD
Authors: GIBILISCO MARINA
Published: July 2002

In this work, I study the propagation of cosmic rays inside the magnetic field of the Earth, at distances d ≤ 500 Km from its surface; at these distances, the geomagnetic field deeply influences the diffusion motion of the particles. I compare the different effects of the interplanetary and of the geomagnetic fields, by also discussing their role inside the cosmic rays transport equation; finally, I present an analytical method to solve such an equation through a factorization technique.
BIOLOGICAL EFFECTS OF COSMIC RADIATION IN LOW-EARTH ORBIT
Authors: DURANTE MARCO
Published: July 2002

Space exploration poses health hazards to the crews of manned missions. Exposure to cosmic radiation and loss of bone density are considered the two most important risk factors for long-term missions. Stochastic risk deriving from cosmic radiation exposure can be estimated by physical dosimeters, using appropriate conversion factors. Recent measurements of space radiation fluence and energy spectra will improve current estimates. Biological dosimetry can be used as a tool to determine the risk directly from biological damage. Chromosomal aberrations in astronauts' peripheral blood lymphocytes have been used as a biomarker of cancer risk. In this paper we will also discuss countermeasures to radiation damage, focusing on the problem of shielding in space.
CALCULATION OF SECONDARY PARTICLES IN ATMOSPHERE AND HADRONIC INTERACTIONS
Authors: BATTISTONI G. , FERRARI A. , SALA P. R.
Published: July 2002

Calculation of secondary particles produced by the interaction of cosmic rays with the nuclei of Earth's atmosphere pose important requirements to particle production models. Here we summarize the important features of hadronic simulations, stressing the importance of the so called "microscopic" approach, making explicit reference to the case of the FLUKA code. Benchmarks are also presented.
NEUTRINOS FROM SUPERNOVAE: EXPERIMENTAL STATUS
Authors: CEI FABRIZIO
Published: July 2002

I discuss the state of the art in the search for stellar collapse neutrinos and the perspectives of this field. The implications for neutrino physics of a high statistics supernova neutrino burst detection by the network of operating experiments are also reviewed.
INTEGRAL: A GAMMA-RAY OBSERVATORY
Authors: PRODUIT NICOLAS
Published: July 2002

INTEGRAL1 is an ESA mission designed to study the γ-ray sky in the 10 keV to 10 MeV energy band. It will build upon previous results and expand our knowledge of the γ-ray astronomy. It is organised as an observatory and thus can be exploited by a wide community.
Finite Temperature Correlations of the Ising Chain in a Transverse Field
Authors: Sachdev Subir
Published: July 2002

Recent work on the finite temperature correlators of the Ising chain in a transverse field is reviewed. The crossover phase diagram in the coupling-constant and temperature plane is discussed, and various exact results and conjectures for static and dynamic correlators are presented.
Statistical Mechanics of Classical Particles with Gravitational Interactions: Exactly Solvable (for N≤∞) in d=1 and d>2
Authors: Kiessling Michael K.-H.
Published: July 2002

This paper is concerned with a curious gap in a string of exactly solvable models, a gap that is suggestively related to a completely integrable nonlinear PDE in d=2 known as Liouville's equation. This PDE emerges in a limit N→∞ from the equilibrium statistical mechanics of classical point particles with gravitational interactions (SMGI) in dimension d=2 which, accordingly, is an exactly solvable continuum model in this limit. Interestingly, in d=1 and all d>2, the SMGI can be, and partly has been, exactly evaluated for all N≤∞. This entitles one to suspect that the SMGI for d=2 is likewise exactly solvable for N>∞, but currently this is an unproven hypothesis. If this conjecture can be answered in the affirmative, spin-offs in various areas associated with Liouville's equation, such as vortex gases, superfluidity, random matrices, and string theory can be expected.
Exact Evaluation of Thermodynamic Quantities for the Integrable T-J Chain
Authors: Klümper A.
Published: July 2002

The supersymmetric tJ model in one dimension is investigated by means of the quantum transfer matrix (QTM). The free energy of the quantum system is given by just the largest eigenvalue of the QTM whereas the next-largest ones determine the correlation lengths at finite temperature. The first step of the analysis consists of an embedding of the QTM into a family of commuting matrices. In the second step the eigenvalues equations are derived by an algebraic Bethe ansatz. Finally, the eigenvalue equations are transformed into a set of nonlinear integral equations. Some numerical results are presented. The specific heat for instance shows the typical Luttinger liquid behavior at low temperatures.
Loop Models, Marginally Rough Interfaces, and the Coulomb Gas
Authors: Kondev Jané
Published: July 2002

We develop a coarse-graining procedure for two-dimensional models of fluctuating loops by mapping them to interface models. The result is an effective field theory for the scaling limit of loop models, which is found to be a Liouville theory with imaginary couplings. This field theory is completely specified by geometry and conformal invariance alone, and it leads to exact results for the critical exponents and the conformal charge of loop models. A physical interpretation of the Dotsenko-Fateev screening charge is found.
Exact Results for a Model Ternary Polymer Mixture
Authors: Pant P. , Wu F. Y. , Barry J. H.
Published: July 2002

A model ternary polymer mixture is considered with bi- and -functional monomers and a solvent embedded on a honeycomb lattice. The model is shown to be equivalent to an eight-vertex model on the same lattice. Using this equivalence which further maps the problem into an Ising model in a non-zero magnetic field, an exact analysis of the model is carried out. The two phase coexistence surface in the temperature- composition space is determined exactly and connectivity properties of the model are studied.
Calculations on Ni Clusters: An Equivalent Crystal Theory and LCAO Approach
Authors: Datta Radhika Prosad , Banerjea Amitava , Mookerjee Abhijit , Bhattacharya Ashok K.
Published: July 2002

The structure and electronic properties of small nickel clusters are studied using Equivalent Crystal Theory (ECT) and a parametrised LCAO method. The minimum energy structure is obtained using ECT with Monte Carlo techniques. The LCAO method is then used to study the electronic properties of the optimised clusters.
Electron Transport Properties of Aluminium Substituted CuTi Amorphous Alloys
Authors: Bhatnagar A. K. , Fritsch G. , Naugle D. G. , Haberkern R. , Kandlbinder M. , Lindqvist P.
Published: July 2002

Room temperature electrical resistivity (ρ), temperature coefficient of resistivity (α) and Hall coefficient (R H ) of ( Cu 1-y Ti y)1-x Al x amorphous alloys, where y=0.36, 0.50 and 0.64 and x=0, 0.05 and 0.10 are presented. The low temperature dependence of resistivity and magnetoresistivity of a-( Cu 0.36 Ti 0.64)1-x Al x are also presented and discussed qualitatively in terms of quantum corrections. It is found that the addition of Al in a- Cu 0.36 Ti 0.64 alloy decreases the spin-orbit scattering time τ so .
Lattice-Vibration Localization in Doped Polythiophene
Authors: Xie S. J. , Han J. S. , Ma X. D. , Mei L. M. , Lin D. L.
Published: July 2002

Vibration modes around bipolarons in polythiophene are investigated numerically by considering a chain of finite length with different boundary conditions within the framework of tight-binding model. When the periodic boundary condition is applied, we find seven localized modes, among which three are of even parity and four of odd parity. One of the even modes is due solely to the influence of sulfur heteroatom in the heterocycle and is believed to be responsible for the mode around 700 cm -1 observed in the Raman spectrum of polythiophene. The dependence of intensities of these localized modes on the chain length is also investigated. When the ends of the chain are left open, it is shown that new surface modes are created from the highest optical branch. These modes may be identified as the high-frequency modes observed in infrared active vibration and resonant Raman scattering absorption experiments.
A Non-Critical String (Liouville) Approach to Brain Microtubules: State Vector Reduction, Memory Coding and Capacity
Authors: Mavromatos N. E. , Nanopoulos D. V.
Published: July 2002

Microtubule (MT) networks, subneural paracrystalline cytoskeletal structures, seem to play a fundamental role in the neurons. We cast here the complicated MT dynamics in the form of a (1+1)-dimensional noncritical string theory, thus enabling us to provide a consistent quantum treatment of MTs, including enviromental friction effects. We suggest, thus, that the MTs are the microsites, in the brain, for the emergence of stable, macroscopic quantum coherent states, identifiable with the preconscious states. Quantum space-time effects, as described by noncritical string theory, trigger then an organized collapse of the coherent states down to a specific or conscious state. The whole process we estimate to take [Formula: see text], in excellent agreement with a plethora of experimental/observational findings. The microscopic arrow of time, endemic in noncritical string theory, and apparent here in the self-collapse process, provides a satisfactory and simple resolution to the age-old problem of how the, central to our feelings of awareness, sensation of the progression of time is generated. In addition, the complete integrability of the stringy model for MT we advocate in this work proves sufficient in providing a satisfactory solution to memory coding and capacity. Such features might turn out to be important for a model of the brain as a quantum computer.
Path-Integral Treatment for Localized Electrons in the Periodic Anderson Model
Authors: Ivanov V. , Pucci R. , Yarunin V. , Zhuravlev M.
Published: July 2002

The partition function of the periodic Anderson model is presented as the path integral over the variables of "slow" localized d-electrons and of "light" conduction s-electrons with the energy half-bandwidth w. The adiabatic approximation is applied for d-electrons with level E<0 through the averaging of the thermal distribution over the "light" s-electron trajectories. The conditions are deduced for the temperature and for the relative positions of s- and d-electron levels, that prove this approximation. Temperature minimum of the effective one-particle d-electron energy with the corresponding maximum of their density of states follow for high temperature and the shallow d-level |E|w and low temperatures.
Superconducting States with the Lattice Distortion in the Extended Hubbard Model
Authors: Miyai Eiji , Ozaki Masa-Aki
Published: July 2002

We give group theoretical classification of superconducting (SC) states with a single SC order parameter in the extended Hubbard model with uniform lattice distortion on the two-dimensional square lattice, by using the mean field approach. We obtain two singlet SCs (s-wave and d-wave) and eight triplet SCs by decomposing the pairing interaction into irreducible components (A1g, B1g and Eu) of point symmetry D4h. We show that in the singlet SC state with a single SC order parameter (s-wave or d-wave) no anisotropic lattice distortion occurs. In the case of triplet SC states, two SC states among eight must be accompanied with anisotropic lattice distortion. The symmetry of SC order parameter uniquely determines the lattice symmetry. We have performed numerical calculations for these SC states, and shown the possibility that one of the SC states with anisotropic lattice distortion becomes most stable of all SC states in the extended Hubbard model.

We also discuss singlet SC states with multiple SC order parameters (s-wave and d-wave). It is shown that the anisotropic distortion must occur in (s+d)-SC states and not in (s+id)-SC state.
The Bak–Sneppen Model: A Self-Organized Critical Model of Biological Evolution
Authors: Pang Ning-Ning
Published: July 2002

Recently, Bak and Sneppen proposed a simple model, the Bak–Sneppen (BS) model, as a coarse-grained description of biological evolution. It has attracted a lot of attention from interdisciplinary statistical physics community, for its simple model definition but extremely rich properties to be explored. The aim of this paper is to give a pedagogical and update review of this fast-developing topic. The emphasis is on the mechanism by which the BS model approaches the self-organized critical state, the universal properties of the system at criticality, and the relation with other topics, such as directed percolation, random walk, and a few self-organized critical models.
Spectral Function Analysis of Fermi Liquids and of Composite Fermions in A Finite Magnetic Field: Renormalised Gaps
Authors: Curnoe S. , Stamp P. C. E.
Published: July 2002

We consider the self-energy and quasiparticle spectrum, for both electrons interacting with phonons, and composite fermions interacting with gauge fluctuations. In both cases we incorporate the singular structure arising from Landau level quantization in a finite field. This is then used to determine the renormalised gap between the Fermi energy and the first excited states.

The electron–phonon problem is treated for both Debye and Einstein phonons. In the case of composite fermions, it is found that the singular Landau level structure strongly affects the renormalised gap in the intermediate coupling regime, which is relevant to experiments on the fractional quantum Hall effect. We compare our findings with measurements of the gap in fractional Hall states with filling fraction ν near ν=1/2.
Kinetics of Pulsed Laser Ablation-Deposition Process: A Case Study of the Ablation of α-Fe2O3 in Hydrogen
Authors: Adhi K. P. , Kale Shilpa , Joshi Sushama , Limaye A. V. , Ogale S. B. , Marest G.
Published: July 2002

The plasma plume formed during pulsed excimer laser ablation from an α- Fe2O3 target in hydrogen ambient is characterized by optical emission spectroscopy, for different hydrogen pressures. The films deposited at the same pressures are also examined by conversion electron Mössbauer Spectroscopy for phase identification. An attempt is made to establish a correlation between the plasma and film properties.
A Classical Method of Magnetic Configuration and Coercive Field for Superlattice Model
Authors: Xie Ning , Zhou Lei , Tao Ruibao
Published: July 2002

We develop a classical approach for determining the magnetic configuration and the coercive field in a superlattice model. The method is applied to calculate the magnetization loop of a sandwich like superlattice, and to discuss the capping effect in double-film structures.
High-Frequency Vortex Critical Dynamics of Superconducting Amorphous Mo3Si Films
Authors: Yeh N.-C. , Kriplani U. , Jiang W. , Kumar J. , Fong H. F. , Reed D. S. , Tsuei C. C.
Published: July 2002

The effects of static disorder on the vortex dynamics of type-II superconductors are investigated by comparing the high-frequency vortex response of superconducting amorphous Mo3Si (a- Mo3Si ) films with that of the high-temperature superconductors. We find that for a- Mo3Si films in the three-dimensional limit, the microwave vortex response near the second-order vortex-solid to vortex-liquid glass transitions is consistent with vortex critical relaxation, in contrast to the diffusion vortex dynamics in high-temperature superconductors at the same frequencies. The observation of microwave vortex critical dynamics in a- Mo3Si is attributed to the extremely disordered nature of the amorphous superconductors, which results in a much shorter-range vortex correlation and therefore a faster critical relaxation.
Density of States and Localization Lengths in One-dimensional Linear Chains
Authors: De Oliveira Mário J. , Petri Alberto
Published: July 2002

The integral equation for computing the density of states of a disordered linear chain of harmonic oscillators is interpreted as describing a stochastic Markov process, and its solution is determined by means of Monte Carlo simulation of the process. It is also shown that, in addition to the localization lengths of the eigenstates, the method allows the computation of the generalized Ljapunov exponents. Many different examples of application, ranging from systems with uncorrelated disorder to deterministic aperiodic chains, are reported.
INFLUENCE OF SECOND-ORDER CORRECTION TO RAYLEIGH SCATTERING ON PANCHARATNAM PHASE IN A THREE-LEVEL ATOM
Authors: ABDEL-ATY M.
Published: July 2002

The Pancharatnam phase for the entangled state of a single three-level atom interacting with a single electromagnetic field mode has been studied. The exact results are employed to perform a careful investigation of the influence of the second-order correction to Rayleigh scattering on the atomic level occupation probabilities as well as the Pancharatnam phase. It is shown that the Pancharatnam phase explicity contains information about the statistics of the field and atomic coherence. The addition of a second-order correction term has an important effect on the properties of the Pancharatnam phase. The results show that the effect of the second-order correction term changes the quasi-period of the Pancharatnam phase evolution.
EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF V4+ IONS IN THE 2B2O3 · SrO GLASS MATRIX
Authors: ARDELEAN I. , COZAR O. , CRACTIUN C. , CEFAN C.
Published: July 2002

Electron paramagnetic resonance (EPR) and magnetic susceptibility studies on x V 2 O 5 · (100 - x) [2 B 2 O 3 · SrO ] glasses with 0 ≤ x ≤ 30 mol% were performed. The covalence degree of vanadium bonds was estimated according to the LCAO-MO model. The EPR data show the presence of V 4+ ions in a square-pyramidal coordination ( C 4v). The experimental EPR spectra are simulated assuming a superposition of two signals, one with hyperfine structure (HFS) typical for isolated ions and the other one consisting of a broad line without the HFS characteristic for clustered ions. These results are consistent with the magnetic data which indicate that for x ≤ 5 mol% V 2 O 5 the temperature dependence of the reciprocal magnetic susceptibility is described by a Curie–Weiss type law with negative paramagnetic Curie temperature. The magnetic data also allow the estimation of N V 4+ / N V total ratio.
BISTABILITY OF HARMONICALLY FORCED RELAXATION OSCILLATIONS
Authors: PHILLIPSON PAUL E. , SCHUSTER PETER
Published: July 2002

Relaxation oscillations appear in processes which involve transitions between two states characterized by fast and slow time scales. When a relaxation oscillator is coupled to an external periodic force its entrainment by the force results in a response which can include multiple periodicities and bistability. The prototype of these behaviors is the harmonically driven van der Pol equation which displays regions in the parameter space of the driving force amplitude where stable orbits of periods 2n ± 1 coexist, flanked by regions of periods 2n + 1 and 2n - 1. The parameter regions of such bistable orbits are derived analytically for the closely related harmonically driven Stoker–Haag piecewise discontinuous equation. The results are valid over most of the control parameter space of the system. Also considered are the reasons for the more complicated dynamics featuring regions of high multiple periodicity which appear like noise between ordered periodic regions. Since this system mimics in detail the less analytically tractable forced van der Pol equation, the results suggest extensions to situations where forced relaxation oscillations are a component of the operating mechanisms.
STABILIZATION OF GLOBAL INVARIANT SETS FOR CHAOTIC SYSTEMS: AN ENERGY BASED CONTROL APPROACH
Authors: LAVAL LAURENT , M'SIRDI NACER K.
Published: July 2002

This paper presents a new control approach for steering trajectories of three-dimensional nonlinear chaotic systems towards stable stationary states or time-periodic orbits. The proposed method mainly consists in a sliding mode-based control design that is extended by an explicit consideration of system energy as basis for both controller design and system stabilization. The control objective is then to regulate the energy with respect to a shaped nominal representation implicitly related to system trajectories. In this paper, we establish some theoretical results to introduce the control design approach referred to as Energy based Sliding Mode Control (ESMC for short). Then, some capabilities of the proposed approach are illustrated through examples related to the chaotic circuit of Chua.
CONTROLLING IN BETWEEN THE LORENZ AND THE CHEN SYSTEMS
Authors: LÜ JINHU , CHEN GUANRONG , ZHANG SUOCHUN
Published: July 2002

This letter investigates a new chaotic system and its role as a joint function between two complex chaotic systems, the Lorenz and the Chen systems, using a simple variable constant controller. With the gradual tuning of the controller, the controlled system evolves from the canonical Lorenz attractor to the Chen attractor through the new transition chaotic attractor. This evolving procedure reveals the forming mechanisms of all similar and closely related chaotic systems, and demonstrates that a simple control technique can be very useful in generating and analyzing some complex chaotic dynamical phenomena.
VARIOUS LEVELS OF MODELS FOR AEROSOLS
Authors: JABIN PIERRE-EMMANUEL
Published: July 2002

Two limit behaviours of a simple model of aerosol are considered. The only force acting on aerosol particles is a friction due to the flow of gas. It is first proved that in the limit of an infinite friction coefficient, the particles are simply advected by the gas. Then we consider very dilute sprays of aerosol, i.e. with distribution functions which are monokinetic (Dirac mass in velocity). This approach leads to a macroscopic system with a free-boundary problem.
BOLTZMANN-LIKE MODELLING OF A SUSPENSION
Authors: CROIZET C. , GATIGNOL R.
Published: July 2002

This paper deals with the presentation of a kinetic model for a suspension of identical hard spheres. Considering that the collisions between particles are instantaneous, binary, inelastic and taking the diameter of the spheres into account, a Boltzmann equation for the dispersed phase is proposed. It allows one to obtain the conservation of mass and momentum as well as, for slightly inelastic collisions, an H-theorem which conveys the irreversibility of the evolution. The problem of the boundary conditions for the Boltzmann equation is then introduced. From an anisotropic law of rebound characterizing the inelastic and non-punctual impact of a particle to the wall, a parietal behavior for the first moments of the kinetic equation is deduced.
FROM MICROSCOPIC TO MACROSCOPIC DESCRIPTION FOR GENERALIZED KINETIC MODELS
Authors: LACHOWICZ MIROSŁAW
Published: July 2002

In this paper a review of some results and research perspectives for the general class of bilinear systems of Boltzmann-like integro-differential equations (generalized kinetic models) describing the dynamics of individuals undergoing kinetic (stochastic) interactions is presented. Some macroscopic limits (the diffusive limit and the hydrodynamic limit) are discussed.
GENERATING CONCISE SETS OF LINEAR REGRESSION RULES FROM ARTIFICIAL NEURAL NETWORKS
Authors: SETIONO RUDY , AZCARRAGA ARNULFO
Published: July 2002

Neural networks with a single hidden layer are known to be universal function approximators. However, due to the complexity of the network topology and the nonlinear transfer function used in computing the hidden unit activations, the predictions of a trained network are difficult to comprehend. On the other hand, predictions from a multiple linear regression equation are easy to understand but are not accurate when the underlying relationship between the input variables and the output variable is nonlinear. We have thus developed a method for multivariate function approximation which combines neural network learning, clustering and multiple regression. This method generates a set of multiple linear regression equations using neural networks, where the number of regression equations is determined by clustering the weighted input variables. The predictions for samples of the same cluster are computed by the same regression equation. Experimental results on a number of real-world data demonstrate that this new method generates relatively few regression equations from the training data samples. Yet, drawing from the universal function approximation capacity of neural networks, the predictive accuracy is high. The prediction errors are comparable to or lower than those achieved by existing function approximation methods.
ENTROPIES OF BRAIDS
Authors: SONG WON TAEK , KO KI HYOUNG , LOS JÉRÔME E.
Published: July 2002

Pseudo-Anosov homeomorphisms are classified by their invariant train tracks. The decomposition of any train track map in elementary folding maps gives a normal form for each train track class. In the case of 4-braids there are three train tracks classes and we give an explicit automaton that generates a normal form for each class. This enables us, for instance, to exhibit the pseudo-Anosov 4-braid with the minimal growth rate. We also show that the growth rate of a pseudo-Anosov braid appears as a root of the Alexander polynomial of a link that shares a common sub-link with the closure of the braid. We finally give a criterion for the faithfulness of the Burau representation for 4-braids.
A NEW THEORY OF ELECTROMAGNETIC, WEAK AND STRONG INTERACTIONS
Authors: PANTELIDES SOKRATES T.
Published: July 2002

The Higgs mechanism for imparting masses to gauge bosons and matter particles is obviated by showing that Yang–Mills gauge bosons have intrinsic nonzero masses (rest-frame energies) from self-interactions. Electroweak (EW) mixing is ruled out because it produces a photon field that is massive, carries EW charge, and does not satisfy Maxwell's equations. Other fundamental difficulties of the Standard Model are identified. A new gauge theory of electromagnetic, weak and strong interactions is derived from the Dirac equation with no other postulates and no free parameters. The three forces are intrinsically unified, the photon field is Maxwellian, weak interactions derive from spin (not isospin), and the weak and strong bosons are naturally massive and chiral. Charge is naturally quantized to integral values. Three generations of lepton pairs and elementary-hadron pairs, all with integral charges, are predicted, contradicting the phenomenology of fractional quark charges, but in full accord with experimental data on weak and strong processes and composite hadrons. Neutrinos are massive. The Dirac masses, the fine structure constant, neutrino oscillations and Cabibbo mixing are shown to have a common origin in the gravitational field. The new theory leads to a new interpretation of "negative energies" with cosmological implications. Finally, it is shown that key expressions of the EW formalism agree with those of the new theory and with experiments only if the mixing angle θ is given by sin 2 θ = 0.25, which accounts for the EW model's successes.
FRACTAL MODELING OF SPEECH SIGNALS
Authors: VÉHEL JACQUES LÉVY , DAOUDI KHALID , LUTTON EVELYNE
Published: July 2002

In this paper, we present a method for speech signal analysis and synthesis based on IFS theory. We consider a speech signal as the graph of a continuous function whose irregularity, measured in terms of its local Hölder exponents, is arbitrary. We extract a few remarkable points in the signal and perform a fractal interpolation between them using a classical technique based on IFS theory. We thus obtain a functional representation of the speech signal, which is well adapted to various applications, as for instance voice interpolation.
CONCURRENT DESIGN OF ENGINEERING SURFACES USING PATCHWORK ANALYSIS
Authors: BROWN CHRISTOPHER A.
Published: July 2002

This paper presents the theoretical basis for a new approach to concurrent engineering of surface topographies. An indispensable element of concurrent engineering of random topographies is a method for describing the topography that captures the essence that is responsible for behavior and is indicative of the manufacturing process and process variables. The approach presented here is based on understanding topographically dependent phenomena as collections of discrete interactions, at certain scales, which can be simulated in a patchwork fashion. It is then possible to estimate the strength of an interaction with a surface and to separate the design process into Euclidean and fractal regimes.
COMPARISON OF SEVERAL METHODS FOR CALCULATING FRACTAL-BASED TOPOGRAPHIC CHARACTERIZATION PARAMETERS
Authors: JOHNSEN WILLIAM A. , BROWN CHRISTOPHER A.
Published: July 2002

The objective of this work is to compare fractal-based, topographic characterization parameters calculated by several different fractal analysis methods. Four fractal characterization methods (compass, patchwork, box counting, and 2-point correlation) are systematically applied to five topographic data sets, which encompass a wide range of scale, and the results are compared. The compass and patchwork methods calculate similar values for the fractal dimension and smooth/rough crossover. The box and 2-point correlation methods calculate similar values for the fractal dimension. The compass and patchwork methods are capable of calculating the smooth/rough crossover.
FRACTAL DIMENSION OF AN AORTIC HEART VALVE LEAFLET
Authors: STERN JULIE V. , PESKIN CHARLES S.
Published: July 2002

The complexity of nature can often be observed in the geometry of biological structure. The aortic valve model of Peskin and McQueen can be used to study the apparently fractal character of the valve's fiber architecture. The branching and braiding of the model fibers is similar to that seen in the real aortic valve. In this study, we compute the fractal dimension of the leaflets of the model aortic valve. We find a fractal dimension of 2.21. The computation of the aortic valve leaflet at the most refined level in the fractal dimension calculation requires the computation of over 6.5 billion points (5.1 million aortic valve fibers with 1280 points/fiber). A high-performance variant of the grid-based box counting method is developed, based on a recursive, octal-tree data structure.
FRACTAL DIMENSIONS OF MYCOSIS FUNGOIDES
Authors: MCGINLEY PATTON , SMITH ROBIN G. , LANDRY JEROME C.
Published: July 2002

Prior to an investigation of early diagnosis of mycosis fungoides (MF) using fractal geometry, we set out to see if MF lesions are fractal in nature. We analyzed three aspects of MF lesions: the dermoepidermal profile of photomicrographs of patch stage lesions and normal skin, the perimeter of patch and plaque stage lesions, and the size distribution of patch and plaque lesions on the skin surface. The perimeter of plaque lesions was measured on close-up photographs by the divider walk method using various step sizes. Based on the perimeter values, the fractal dimension was determined. The dermoepidermal profile of MF patch lesions was analyzed by the divider walk method for self-affine fractals. The size distribution of MF patch and plaque lesions was determined by counting the number of patch and plaque lesions with an area greater than or equal to a specific size A on scaled photographs of a 19.6 cm × 19.6 cm affected region. A plot of number of lesions with area greater than or equal to A vs. lesion area on log-log paper allows the detection of a power-law distribution, indicative of one type of self-similar fractals. The dermoepidermal profile of patch stage lesions and normal skin was found to be self-affine fractals. Global measurements of normal thin skin and of patch stage lesions were distinct. All observed patch and plaque lesion area distributions were a fractal set. The perimeter of non-confluent plaque lesions was not fractal. This work revealed fractal dimensions in two aspects of MF lesions. Further investigation of application of fractal geometry to the diagnosis and staging of MF is planned.
ABSORPTION OF OPTICAL PULSES UNDER PROPAGATION THROUGH ONE-DIMENSIONAL RESONANT FRACTAL CLUSTERS
Authors: KISTENEV YU. V. , SHAPOVALOV A. V.
Published: July 2002

Peculiarities of propagation of short optical pulses through resonantly absorbing fractal media are investigated in the work using methods of numerical simulation. The fractal object was modeled by a one-dimensional structure with its parameters being similar to generalized Cantor dust. The dependence of transmission of such a medium on its Hausdorff dimension in some cases was shown to have a nonmonotonous character. Interpretation of the results obtained is also given.
SCALING LAW OF EARTHQUAKE ENERGY: A MODIFICATION IN THE VIEW OF BROAD FREQUENCY BAND
Authors: WU ZHONGLIANG , GAO YUAN
Published: July 2002

We analyzed the NEIC broadband energy catalogue and found that the scaling law of earthquake energy deduced from Gutenberg-Richter's law is not valid. The analysis of broadband energy, however, shows a scaling law even better than expected from "classical magnitudes".
STOCHASTIC VOLATILITY
Authors: SABANIS SOTIRIOS
Published: July 2002

Hull and White [1] have priced a European call option for the case in which the volatility of the underlying asset is a lognormally distributed random variable. They have obtained their formula under the assumption of uncorrelated innovations in security price and volatility. Although the option pricing formula has a power series representation, the question of convergence has been left unanswered. This paper presents an iterative method for calculating all the higher order moments of volatility necessary for the process of proving convergence theoretically. Moreover, simulation results are given that show the practical convergence of the series. These results have been obtained by using a displaced geometric Brownian motion as a volatility process.
In Korea, the Thirst for Funds Drives Change
Authors: Root Hilton L. , Abdollahian Mark Andrew , Kugler Jacek
Published: July 2002

It is widely acknowledged that Korea will not be secure against future economic crisis without structural reform of finance, enterprise and labor markets. Real reform requires a transfer of authority from the government to market-based institutions, forcing banks to take full responsibility for the loans they authorize. Before the crisis, the government implicitly insured depositors' bank loans made to the large conglomerates, leaving banks little incentive to develop the necessary skills in credit analysis and loan monitoring. The insured agents did not take proper care to manage their risks. Moral hazard or will increased government control over the financial sector weaken market discipline?
VIBRATION AND DYNAMIC INSTABILITY OF STIFFENED PLATES SUBJECTED TO IN-PLANE HARMONIC EDGE LOADING
Authors: SRIVASTAVA A. K. L. , DATTA P. K. , SHEIKH A. H.
Published: July 2002

The vibration and dynamic instability behavior of a stiffened plate subjected to uniform in-plane edge loading is studied using finite element analysis. The method of Hill's infinite determinants is applied to analyze the dynamic instability regions. Rectangular stiffened plates possessing different boundary conditions, aspect ratios, varying mass and stiffness properties and varying number of stiffeners have been analyzed for dynamic instability. The results are obtained considering the bending displacements of the plate and the stiffener. Eccentricity of the stiffeners give rise to axial and bending displacement in the middle plane of the plate. The results show that the principal instability regions have a significant effect considering and neglecting in-plane displacements. Comparison with published results indicates good agreement.
A SUB-VECTOR WEIGHTING SCHEME FOR IMAGE RETRIEVAL WITH RELEVANCE FEEDBACK
Authors: WANG LEI , CHAN KAP LUK , XIONG XUEJIAN
Published: July 2002

In image retrieval with relevance feedback, feature components are weighted to reflect the high-level concepts, and a user's subjective perception, embodied in the images labelled by the user in the feedback. However, the number of labelled images is often small and the covariance matrix needed for weighting will be singular. For this reason, the commonly used methods discard the mutual correlation among the feature components completely and use a diagonal covariance matrix. In this paper, a sub-vector weighting scheme is proposed. This scheme partitions a multi-dimensional visual feature vector into multiple low-dimensional sub-vectors. The singularity of the covariance matrix for each sub-vector can be avoided due to the lower dimensionality of the sub-vectors. Thus, the mutual correlation in each sub-vector can be retained for weighting and an optimally weighted similarity metric can be applied on each sub-vector. The similarity scores obtained from different sub-vectors are combined, as the final score, to rank the database images. Experimental results demonstrated that the proposed weighting scheme can significantly improve the efficacy of image retrieval with relevance feedback.
A PRACTICAL APPROACH FOR 3D BUILDING MODELING FROM UNCALIBRATED VIDEO SEQUENCES
Authors: LIU YONG , WU CHENG-KE , TSUI HUNG-TAT
Published: July 2002

This paper presents an approach for reconstructing a realistic 3D model of a building from its uncalibrated video sequences taken by a hand-held camera. The novelty of this approach lies in the integration of some prior scene knowledge in the different stages of the Structure From Motion problem (SFM). First, the coplanarity of buildings is considered in the calculation of the fundamental matrices to deal with the critical configurations. Second, the line parallelism and plane orthogonality are transformed to the constraints on the absolute quadric during camera auto-calibration. This makes some critical cases solvable and the reconstruction more Euclidean. The approach is implemented and validated using simulated data and real image data. The experimental results at the end of the paper show the effectiveness of our approach.
THE DETECTION OF OBSTACLES BY THE HORIZON VIEW CAMERA
Authors: IWATA AYAMI , KATO KUNIHITO , YAMAMOTO KAZUHIKO
Published: July 2002

We propose a new camera system called the Horizon View Camera (HVC), which can be installed in a small size robot. The HVC is a system in which the optical axis of the camera is directed to the horizon using a mirror. The obtained image consists only of objects without the ground. Therefore, by using the HVC system, distinguishing the object from the ground becomes very easy. We demonstrate the effectiveness of the HVC with experiments on the detection of the distance to the object by using features of the HVC.
ORBITAL NOISE IN THE EARTH SYSTEM IS A COMMON CAUSE OF CLIMATE AND GREENHOUSE-GAS FLUCTUATION
Authors: LIU H. S. , KOLENKIEWICZ R. , WADE C.
Published: July 2002

The mismatch between fossil isotopic data and climate models known as the cool-tropic paradox implies that either the data are flawed or we understand very little about the climate models of greenhouse warming. Here we question the validity of the climate models on the scientific background of orbital noise in the Earth system. Our study shows that the insolation pulsation induced by orbital noise is the common cause of climate change and atmosqheric concentrations of carbon dioxide and methane. In addition, we find that the intensity of the insolation pulses is dependent on the latitude of the Earth. Thus, orbital noise is the key to understanding the troubling paradox in climate models.