bluuebunny/crossref_metadata_2025 huggingface dataset:
THE SEMICONTINUOUS BOLTZMANN EQUATION: TOWARDS A MODEL FOR FLUID DYNAMIC APPLICATIONS
Authors: LONGO E. , PREZIOSI L. , BELLOMO N.
Published: November 2004

This paper proposes a semicontinuous model of the Boltzmann equation for gas particles moving in the plane in all possible directions, but with a finite, large, number of velocity moduli. The model, called the n-semicontinuous Boltzmann equation, consists in a system of integro-differential equations with one-fold integrals over a suitable angular variable. Thermodynamic equilibrium is studied in details. The model is then applied to the analysis of a temperature jump problem. The results are compared with the ones obtained by continuous models of the Boltzmann equation.
SOME IMBEDDING THEOREMS AND THE SOLVABILITY OF THE SYSTEM OF HYPERBOLIC-PARABOLIC EQUATIONS
Authors: AGOSHKOV V.I.
Published: November 2004

A number of physical problems is described by a system of first order hyperbolic equations in a subregion of the physical domain, and of parabolic equations in the complementary domain. To state these problems correctly an investigation of the existence of the trace for a function which possesses a weak derivative in some direction is needed. This problem is solved in the paper. Also we formulate the problem for hyperbolic-parabolic equations (including the description of the transmission condition on the internal boundary), then we prove its solvability.
ON A SYSTEM OF NONLINEAR HYPERBOLIC CONSERVATION LAWS WITH SOURCES
Authors: LOGAN J. DAVID , SHORES THOMAS S.
Published: November 2004

We study the existence of travelling reaction fronts connecting equilibrium states in the nonlinear reactive-convective system [Formula: see text] where r represents a given chemical reaction rate of a reversible reaction A⇌B, and f(u)=(2−u)(u−1) represents a nonlinear heat source. The original model equations for irreversible reactions and without sources were motivated by an analog of reactive flow and detonation processes posed by Fickett and Majda. It is shown that endothermic compressions exist for wave speeds c≥2 and in this case, a singular perturbation method is developed to find a two-term analytic approximation for the waveforms. For wavespeeds 0<c<c*<1, for some c*=c*(q), nonmonotonic travelling waves exist. These subsonic travelling waves have either an oscillating tail or a minimum occurring at a finite value, and they essentially represent exothermic rarefaction waves. In this latter case a singular line in the flow comes into play, and a method of analysis is developed based on desingularization of the phase plane equations.
ON THE SPATIAL DECAY OF ILL-POSED PARABOLIC PROBLEMS
Authors: LIN CHANGHAO , PAYNE L.E.
Published: November 2004

This paper investigates the spatial decay of solutions to two ill-posed parabolic initialboundary value problems: 1) the backward heat equatoin defined on a semi-infinite cylinder in ℝN and 2) the backward Stokes flow equations defined on a semi-infinite strip in ℝ2.
CHAOTIC MOTION OF TWO MOLECULES IN A BOX
Authors: HASEGAWA M. , NANBU K. , IWATA K.
Published: November 2004

Motion of two molecules in a specularly reflecting box is analyzed for two-, three- and higher-dimensional cases. The temporal behavior of this nonlinear system is pursued by the molecular-dynamics method. The distributions of molecular velocities and collisional points are examined for two- and three-dimensional cases. Strange patterns, which depend on the initial condition of the system, have been found in velocity and physical spaces. The reason of this remarkable feature is discussed. The energy distribution function is also examined for a molecule in chaotic motion. The distribution depends on the dimension of the physical space. It can be described by the beta distribution, which holds in general for any dimension.
GLOBAL WEAK SOLUTIONS OF THE ONE-DIMENSIONAL HYDRODYNAMIC MODEL FOR SEMICONDUCTORS
Authors: JOCHMANN F.
Published: November 2004

The existence of a global weak solution of the one-dimensional hydrodynamic model for semiconductors is proved by the method of artificial viscosity and the theory of compensated compactness.

The system is first regularized and global viscosity-solutions are constructed. Letting the viscosity-parameter tend to zero, we obtain a sequence of viscosity-solutions converging in L∞-weak* to a weak solution of the one-dimensional p-system from isoentropic gas dynamics with an electric field term and momentum relaxation.

Since the equations are nonlinear and the convergence is only weak, the theory of Young-measures and compensated compactness is applied to obtain a weak solution of the limit problem.
POSITIVE SOLUTIONS OF NONLINEAR ELLIPTIC SYSTEMS
Authors: CAÑADA A. , GÁMEZ J.L.
Published: November 2004

In this paper we prove the existence of nonnegative and non-trivial solutions of problems of the form [Formula: see text] Our main result improves many previous results of other authors and it may be applied to study the three standard situations: competition, prey-predator and cooperative models. We also cover some other cases which, due essentially to the spatial dependence or to a nonlinear interaction, are not any of these three types. The method of proof combines a decoupling method with a global bifurcation result.
AUTOMATIC FUNCTIONAL MODEL GENERATION FOR PARALLEL FAULT AND DESIGN ERROR SIMULATIONS
Authors: CHANG SHUCHIH ERNEST , SZYGENDA STEPHEN A.
Published: November 2004

The domain specific automatic programming technique was applied to the design and implementation of an automatic functional model generation system (AFMG) for effectively and efficiently creating simulation models of digital systems. The application domain knowledge, involved in a time-consuming and error-prone process for element modeling, was identified, organized, and incorporated into the AFMG as internal rules to guide several transformation processes for converting various forms of model specification, step by step, into desired functional models. Other design issues, such as incomplete specification handling, different signal representations, multiple-valued model generation, interaction of algorithm and data structure selection, …etc., were also carefully addressed and resolved during the design process of the AFMG system. Experimental results show that AFMG can significantly reduce the development time of creating functional models for digital logic simulation.
SYMBOL RECOGNITION IN A CAD ENVIRONMENT USING A NEURAL NETWORK
Authors: YANG DERSHUNG , RENDELL LARRY A. , WEBSTER JULIE L. , SHAW DORIS S. , GARRETT JAMES H.
Published: November 2004

A new neural network called AUGURS is designed to assist a user of a Computer-Aided Design system in utilizing standard graphic symbols. With AUGURS, the CAD user can avoid searching for standard symbols in a large library and rely on AUGURS to automatically retrieve those symbols resembling the user’s drawing. More specifically, AUGURS inputs a bitmap image normalized with respect to location, size, and orientation, and outputs a list of standard symbols ranked by its assessment of the similarity between the symbol and the input image. Only the top ranked symbols are presented to the user for selection. AUGURS encodes geometric knowledge into its network structure and carefully balances its discriminant power and noise tolerance. The encoded knowledge enables AUGURS to learn reasonably well despite the limited number of training examples, the most serious challenge for the CAD domain. We have compared AUGURS with the Zipcode Net, a traditional layered feed-forward network with an unconstrained structure, and a network that inputs either Zernike or pseudo-Zernike moments. The experimental results conclude that AUGURS can achieve the best recognition performance among all networks being compared with reasonable recognition and learning efficiency.
VISUALIZING DYNAMIC ARTIFICIAL INTELLIGENCE ALGORITHMS AND APPLICATIONS
Authors: PERLIN MARK W.
Published: November 2004

Visualization is an important component of modern computing. By animating the course of an algorithm’s temporal execution, many key features can be elucidated. We have developed a general framework, termed Call-Graph Caching (CGC), for automating the construction of many complex AI algorithms. By incorporating visualization into CGC interpreters, principled animations can be automatically displayed as AI computations unfold.

(1) Systems that support the automatic animation of AI algorithms must address these three design issues:

(2) How to represent AI data structures in a general, uniform way that leads to perspicuous animation and efficient redisplay.

(3) How to coordinate the succession of graphical events.

(4) How to partition AI graphs to provide for separate, uncluttered displays. CGC provides a natural and effective solution to all these concerns.

(5) We describe the CGC method, including detailed examples, and motivate why CGC works well for animation. We discuss the CACHE system, our CGC environment for AI algorithm animation. We demonstrate the animation of several AI algorithms – RETE match, linear unification, arc consistency, chart parsing, and truth maintenance – all of which have been implemented in CACHE. Finally, we discuss the application of these methods to interactive interfaces for intelligent systems, using molecular genetics as an example domain.
MULTI-LAYERED HYBRID ARCHITECTURE TO SOLVE COMPLEX TASKS OF AN AUTONOMOUS MOBILE ROBOT
Authors: TIECHE F. , FACCHINETTI C. , HUGLI H.
Published: November 2004

In this paper, we present the implementation of an autonomous mobile robot controller developed according to the principle of a multi-layered hybrid architecture. This architecture is composed of four layers: sensori-motor, behavioral, sequencing, and strategic. The paper describes its general structure and the function of its main elements. It further analyses the development of an example task presenting the advantages of the hybrid architecture.
A FRAMEWORK FOR ENFORCEABLE SPECIFICATION OF EXTENDED TRANSACTION MODELS AND TRANSACTIONAL WORKFLOWS
Authors: GEORGAKOPOULOS DIMITRIOS , HORNICK MARK F.
Published: November 2004

A variety of extensions to the traditional (ACID) transaction model have resulted in a plethora of extended transaction models (ETMs). Many of these ETMs are application-specific, i.e. they are designed to provide correctness guarantees adequate for a particular application, but not others. Similarly, an application-specific ETM may impose restrictions that are unacceptable in one application, yet required in another. To define new ETMs, to determine whether an ETM is appropriate for an application, and to integrate ETMs to produce new ETMs, we need a framework for ETM specification and reasoning. In this paper, we describe such a framework. Our framework supports implementation-independent specification of ETMs described in terms of dependencies between transactions. Dependencies are specified using dependency descriptors. Unlike other transaction specification frameworks, dependency descriptors use a common set of primitives, and are enforceable, i.e. can be evaluated at any time during transaction execution to determine whether issued operations violate ETM specifications. We discuss specifications of (i) structure dependencies between transaction states, and (ii) correctness dependencies for serializability, various cooperative and temporal correctness criteria, and recoverability. We give ETM specification examples for a telecommunications application illustrating the definition of a new application-specific ETM using our framework.
A POLYNOMIAL INVARIANT VIA REPRESENTATION SPACES
Authors: HEUSENER MICHAEL
Published: November 2004

The purpose of this paper is to consider the [Formula: see text]–representation space of knot groups in order to define a polynomial invariant of the knot. Moreover, we would like to study these invariants in special cases and to prove that the polynomial is not trivial if the knot has a non-trivial longitude invariant.
TOPOLOGICAL IMITATION, MUTATION AND THE QUANTUM SU(2) INVARIANTS
Authors: KAWAUCHI AKIO
Published: November 2004

It is proved that any two mutative closed oriented 3-manifolds have the same quantum SU(2) invariant. By a constructive argument of topological imitation, we construct finitely many mutative hyperbolic imitations of any given closed oriented 3-manifold with certain arbitrariness of isometry groups whose quantum SU(2) invariants are close to the original one.
TEMPERLEY-LIEB ALGEBRAS FOR NON-PLANAR STATISTICAL MECHANICS — THE PARTITION ALGEBRA CONSTRUCTION
Authors: MARTIN PAUL
Published: November 2004

We give the definition of the Partition Algebra Pn(Q). This is a new generalisation of the Temperley–Lieb algebra for Q-state n-site Potts models, underpinning their transfer matrix formulation on arbitrary transverse lattices. In Pn(Q) subalgebras appropriate for building the transfer matrices for all transverse lattice shapes (e.g. cubic) occur. For [Formula: see text] the Partition algebra manifests either a semi-simple generic structure or is one of a discrete set of exceptional cases. We determine the Q-generic and Q-independent structure and representation theory. In all cases (except Q = 0) simple modules are indexed by the integers j ≤ n and by the partitions λ ˫ j. Physically they may be associated, at least for sufficiently small j, to 2j 'spin' correlation functions.

We exhibit a subalgebra isomorphic to the Brauer algebra.
LISSAJOUS KNOTS
Authors: BOGLE M. G. V. , HEARST J. E. , JONES V. F. R. , STOILOV L.
Published: November 2004

A Lissajous knot is defined to be one isotopic to a knot which admits a parametrization (for 0≤t≤2π) [Formula: see text]

Motivation for considering Lissajous knots came originally from the study of DNA molecular configurations. We will show that a Lissajous knot necessarily has Kervaire invariant zero so that the trefoil, figure-8 and the (2,5) torus knot are not Lissajous. The knot 52 can be realized with nx = 2, ny = 3, nz = 7.
ENERGY FUNCTIONS FOR POLYGONAL KNOTS
Authors: SIMON JONATHAN K.
Published: November 2004

We define a scale-invariant energy function for polygonal knots in ℜ3 based on the minimum distances between segments. The energy is bounded below by 2π. (minimum crossing number of the knot type). For each knot type, there exists an ideal number of segments, from which can be made an ideal conformation of the knot having minimum energy among all polygons realizing that knot type. Results leading to this include the following: The energy of an n-segment polygon is greater than n; if energy is bounded then ratios of edge lengths and angles are bounded away from zero; changing knot type requires passing an infinite energy barrier. We implement an algorithm, with the feature that preserving knot-type is guaranteed, to discover local energy-minimizing conformations for a given number of segments, and present some of these examples.
STATISTICAL MECHANICS AND TOPOLOGY OF SURFACES IN ${\mathcal Z}^d$
Authors: JANSE VAN RENSBURG E. J.
Published: November 2004

The role of topology in the statistical mechanics of surfaces in the lattice [Formula: see text] is considered. The possibility that a phase transition driven by the number of boundary components occurs is investigated. Bounds on the limiting free energy is derived and conditions for the existence of a critical point in the phase diagram are presented.
ON RANDOM KNOTS
Authors: DIAO YUANAN , PIPPENGER NICHOLAS , SUMNERS DE WITT
Published: November 2004

In this paper, we consider knotting of Gaussian random polygons in 3-space. A Gaussian random polygon is a piecewise linear circle with n edges in which the length of the edges follows a Gaussian distribution. We prove a continuum version of Kesten's Pattern Theorem for these polygons, and use this to prove that the probability that a Gaussian random polygon of n edges in 3-space is knotted tends to one exponentially rapidly as n tends to infinity. We study the properties of Gaussian random knots, and prove that the entanglement complexity of Gaussian random knots gets arbitrarily large as n tends to infinity. We also prove that almost all Gaussian random knots are chiral.
GENERALIZED SPIN MODELS
Authors: KAWAGOE KENICHI , MUNEMASA AKIHIRO , WATATANI YASUO
Published: November 2004

We introduce a generalization of spin models by dropping the symmetry condition. The partition function of a generalized spin model on a connected oriented link diagram is invariant under Reidemeister moves of type II and III, giving an invariant for oriented links.
MINIJETS AND THE MULTIPLICITY DEPENDENCE OF THE AVERAGE TRANSVERSE MOMENTUM IN HIGH ENERGY NUCLEAR COLLISIONS
Authors: NAVARRA F.S. , TRELEANI D.
Published: November 2004

We make predictions for the correlation between 〈pT〉 and the multiplicity in the context of the minijet formalism applied to very high energy nuclear collisions. 〈pT〉 is shown to depend almost linearly on n and the slope of this approximate straight line increases for the noncentral rapidity region. Comparison with predictions made by hydrodynamical models is made.
QUANTUM TUNNELING IN OPEN SYSTEMS
Authors: STEFANESCU E. , SǍNDULESCU A. , GREINER W.
Published: November 2004

We study the barrier penetrability in the frame of the Lindblad theory of open quantum systems. In addition to the diagonal elements of the density matrix, leading to the Gamow’s formula, new terms, describing energy dissipation and spectral line broadening effects are obtained. It is shown that the presence of a dissipative environment increase the barrier penetrability, in accordance with a very simple physical interpretation: for a system initially found in its ground state the dissipation can lead only to transitions to the reaction channels where lower-energy levels exist.
MEASUREMENT OF 79Br(n, 2n)78Br, 63Cu(n,2n)62Cu, 58Ni(n,2n)57Ni, 54Fe(n,2n)53Fe, 50Cr(n, 2n)49Cr AND 46Ti(n, 2n)45Ti REACTION CROSS-SECTIONS AT 14.7 MeV NEUTRON ENERGY
Authors: PANSARE G.R. , BHORASKAR V.N.
Published: November 2004

Cross-sections of the reactions 79 Br (n, 2n)78 Br , 63 Cu (n,2n)62 Cu , 58 Ni (n, 2n)57 Ni , 54 Fe (n, 2n)53 Fe , 50Cr(n, 2n)49Cr and 46 Ti (n, 2n)45 Ti induced by 14.7 MeV neutrons are measured with reference to 27Al(n, ∝)24 Na and 56 Fe (n, p)56 Mn reactions using activation technique and also derived theoretically using compound nucleus model, semiempirical relation and ALICE code. Accuracy around 5% was achieved in measurement of these reaction cross-sections which is better compared to existing literature values.
LIMITING ANHARMONICITY OF SOFT NUCLEI
Authors: ZELEVINSKY V.G.
Published: November 2004

Soft transitional nuclei are considered in a model of a finite superfluid Fermi system in the vicinity of a phase transition. Microscopic estimates are given for the limiting strength of anharmonicity in such a system. The estimates are based on collectivity, adiabaticity and quadrupole symmetry of large amplitude collective motion. The results imply the leading role of quartic anharmonicity and the O(5) dynamical symmetry of low-lying spectra. It justifies the phenomenological model suggested earlier which turned out to be quite successful in description of data.
(j, 0) ⊕ (0, j) COVARIANT SPINORS AND CAUSAL PROPAGATORS BASED ON WEINBERG FORMALISM
Authors: AHLUWALIA D.V. , ERNST D.J.
Published: November 2004

A pragmatic approach to constructing a covariant phenomenology of the interactions of composite high-spin hadrons is proposed. Because there are no known wave equations without significant problems, we propose to construct the phenomenology without explicit reference to a wave equation. This is done by constructing the individual pieces of a perturbation theory and then utilizing the perturbation theory as the definition of the phenomenology. The covariant spinors for a particle of spin j are constructed directly from Lorentz invariance and the basic precepts of quantum mechanics following the logic put forth originally by Wigner and developed by Weinberg. Explicit expressions for the spinors are derived for j=1, 3/2 and 2. Field operators are constructed from the spinors and the free-particle propagator is derived from the vacuum expectation value of the time-order product of the field operators. A few simple examples of model interactions are given. This provides all the necessary ingredients to treat at a phenomenological level and in a covariant manner particles of arbitrary spin.
THE STATUS OF TWO-NEUTRINO AND NEUTRINOLESS DOUBLE BETA DECAY SEARCHES
Authors: MOE M.K.
Published: November 2004

Substantial progress has been made in double beta decay experiments in the past few years, including the beginning of sensitive new searches for neutrinoless double beta decay, and several additional positive detections of the two-neutrino mode by geochemical, radiochemical, and direct-counting techniques. This review discusses the recent experimental activity.
QUARK STARS IN CHIRAL COLOR DIELECTRIC MODEL
Authors: GHOSH SANJAY K. , SAHU PRADIP K.
Published: November 2004

The nonlinear chiral extension of color dielectric model has been used in the present work to study the properties of quark stars. Assuming that the square of meson fields develops nonzero expectation value, the thermodynamic potential for charge neutral interacting two- and three-flavor quark matter, in beta equilibrium, has been calculated up to second order in quark gluon interaction term in the Lagrangian. The equation of state has been found to be softer for higher quark masses and interaction strength. The quark stars properties are found to be dependent on EOS. The mass, radius, moment of inertia and gravitational red shift decrease as the equation of state becomes more soft.
COULOMB EFFECT IN THE TRINUCLEON SYSTEM IN AN OPTICAL POTENTIAL MODEL
Authors: ADHIKARI SANDHAN K. , DELFINO A.
Published: November 2004

A Saxon-Woods type nucleon-deuteron optical potential is suggested and applied numerically to the study of the static Coulomb effect in the low-energy trinucleon system. In particular, the observed correlations between the static Coulomb energy of 3He and the triton binding energy and that between the neutron-deuteron and the proton-deuteron scattering lengths are simulated with this optical potential, In view of this study and a previous one employing two other effective potentials, it is unlikely that a study of the usual static Coulomb effect in the trinucleon system will reveal new and meaningful physics.
SYMMETRY BREAKING IN THE SPECTROSCOPY OF THE ODD-A Ra ISOTOPES
Authors: SHELINE RAYMOND K.
Published: November 2004

The spectroscopy of the odd-A Ra isotopes from 215 Ra through 227 Ra is analyzed to see the effects of octupole deformation on the transition from spherical nuclei (where the more degenerate shell model applies) to quadrupole deformed nuclei (where the less degenerate Nilsson model is operative). 215 Ra with 127 neutrons can be interpreted qualitatively in terms of the weak coupling of the levels in 214 Ra with the shell model states g9/2 and j15/2. 217 Ra and 219 Ra can be understood in terms of both shell model spectroscopy with octupole correlations and increasingly with 219Ra in terms of octupole deformed Nilsson levels. 221,223,225 Ra are all relatively good examples of the octupole deformed model with, however, some differences in the Coriolis coupling between low lying K=3/2± and K=1/2± parity doublet bands. The spectrum of 227 Ra shows the coexistence of both parity doublets and an octupole vibration expected for an octupole-quadrupole deformed system and a coexisting normal deformed system.
EFFECTS ON FORMATION TIME AND COLOUR TRANSPARENCY ON THE PRODUCTION OF LEADING PARTICLES OFF NUCLEI
Authors: KOPELIOVICH BORIS , NEMCHIK JAN , LITOV LEANDR
Published: November 2004

Leading-particle production in hadron-nucleus interactions at high energies is free from influence of nuclear cascading and is most sensitive to the effects of formation time of particle production. Besides these processes are sensitive to inelastic corrections which make nuclei more transparent. This provides a possibility for testing QCD predictions of nuclear colour transparency which is a special case of inelastic shadowing. We developed an approach based 011 the dual string model that takes into account all these effects. We tested this scheme on a large variety of processes and found nice agreement with experimental data.
A WAY TO EVALUATE THE LEVEL DENSITY, TOTAL WIDTH AND COMPOUND-NUCLEUS DECAY FUNCTIONS IN THE RANGE OF UNRESOLVED RESONANCES
Authors: D’ARRIGO ALBERTO , GIARDINA GIORGIO , TACCONE ANNA , HASSANI GERO , OLKHOVSKY VLADISLAV
Published: November 2004

A new relationship between temporal and resonance characteristics for a nuclear reaction in the range of unresolved resonances is derived and analyzed. By using this relationship, we describe a procedure to determine the level density and total resonance width, starting from the experimental data on the cross-sections and some duration functions and obtaining the values not only of the mean durations but also of their variances.
EFFECTIVE VALENCE SPACES AND COLLECTIVITY IN NEUTRON DEFICIENT Dy-Pt NUCLEI
Authors: CHOU W.-T. , CASTEN R.F. , GILL R.L. , ZAMFIR N.V. , BRENNER D.S.
Published: November 2004

The energies of [Formula: see text] states in even-even nuclei from Dy to W are shown to be linear in the P-factor and can be described using the same slope prescription for all these nuclei. Deviations are found for Os and Pt isotopes with N<104 but by including the effects of intruder states, these isotopes can also be well described with the same slope prescription as for Dy-W by using a simple scheme that invokes an effective Np. The results for N>104 give evidence for a more complex structural evolution beyond midneutron shell.
GROUND BAND ENERGIES OF ROTATIONAL AND VIBRATIONAL NUCLEI: I
Authors: DRENSKA S. , GEORGIEVA A. , IVANOV M. , MAVRODIEV S. , ROUSSEV R. , RAYCHEV P.
Published: November 2004

An investigation of the dependence of the ground band and quasi-ground energies of rotational and vibrational nuclei on the nuclear shell characteristics is proposed. Respectively, two formulae for the moment of inertia of well-deformed nuclei and for the vibrational frequency of spherical ones are obtained. By means of these formulae, the ground band energies of the 330 experimental low-lying states of 70 rotational nuclei and 92 states of 35 vibrational ones are reproduced.
ON THE EQUALITY OF ELECTRIC MULTIPOLE MOMENT EXPECTATION VALUES FOR SINGLE-PARTICLE STATES WITH EQUAL TOTAL ANGULAR MOMENTUM
Authors: MAVROMATIS HARRY A.
Published: November 2004

The expectation value of single-particle electric multipole moments is shown to be independent of the orbital angular momentum for pairs with the same total angular momentum. Thus, the well-known equality of the expectation value of the electric quadrupole moment of such pairs is shown to extend to all electric multipoles.
NOTE ON THE MEASUREMENT OF y-DEPENDENCE IN NEUTRINO-ELECTRON SCATTERING: A SENSITIVE TEST OF THE STANDARD MODEL
Authors: RANGACHARYULU C. , RICHTER A.
Published: November 2004

It is pointed out that the y-dependence of the differential cross-section for various types of neutrinos on the electron promises to be a sensitive testing ground of the electroweak Standard Model at KAON in Vancouver. Estimates of the flux requirements are given and the feasibility of such experiments is discussed.
A UNIFIED SHELL-MODEL PICTURE OF NUCLEAR DEFORMATION
Authors: PITTEL S. , FEDERMAN P.
Published: November 2004

A unified shell-picture of nuclear deformation that was first introduced in the late 1970s is briefly reviewed in the context of recent developments in the field.
NUCLEAR DEFORMATIONS AS A SPONTANEOUS SYMMETRY BREAKING
Authors: NAZAREWICZ WITOLD
Published: November 2004

Why can certain nuclei be described in terms of intrinsic shapes with non-spherical, triaxial, or reflection-asymmetric static moments? At first glance a violation of very fundamental symmetries such as rotational invariance, space inversion, or particle number symmetry is astonishing since strong interactions do actually conserve angular momentum, parity, and baryon number. The main building blocks of the spontaneous symmetry breaking mechanism in atomic nuclei are discussed and illuminated by examples taken from atomic and nuclear physics.
THE COMPOSITE PARTICLE REPRESENTATION APPROACH TO BOSON MAPPING
Authors: Wu Cheng-Li
Published: November 2004

The composite particle representation theory (CPRT) and its application to boson mapping is reviewed. The symmetry limits of the Fermion Dynamical Symmetry Model (FDSM) is employed as a solvable model to test the validity of various boson mapping approaches. It is shown that the composite particle representation approach is a very powerful tool for boson mapping. The spurious state problem is also discussed.
BOSON MAPPINGS FOR BOSON SYSTEMS
Authors: PITTEL S. , BIJKER R. , DUKELSKY J.
Published: November 2004

Boson mapping techniques are extended to systems of interacting bosons and then used to extract information regarding unphysical states.
A NEURAL NETWORK PRIMER
Authors: ABDI H.
Published: November 2004

Neural networks are composed of basic units somewhat analogous to neurons. These units are linked to each other by connections whose strength is modifiable as a result of a learning process or algorithm. Each of these units integrates independently (in paral lel) the information provided by its synapses in order to evaluate its state of activation. The unit response is then a linear or nonlinear function of its activation. Linear algebra concepts are used, in general, to analyze linear units, with eigenvectors and eigenvalues being the core concepts involved. This analysis makes clear the strong similarity between linear neural networks and the general linear model developed by statisticians. The linear models presented here are the perceptron and the linear associator. The behavior of nonlinear networks can be described within the framework of optimization and approximation techniques with dynamical systems (e.g., like those used to model spin glasses). One of the main notions used with nonlinear unit networks is the notion of attractor. When the task of the network is to associate a response with some specific input patterns, the most popular nonlinear technique consists of using hidden layers of neurons trained with back-propagation of error. The nonlinear models presented are the Hopfield network, the Boltzmann machine, the back-propagation network and the radial basis function network.
LESIONING MCCLOSKEY AND LINDEMANN’S (1992) MATHNET: THE EFFECT OF DAMAGE LOCATION AND AMOUNT
Authors: LORIES G. , AUBRUN A. , SERON X.
Published: November 2004

McCloskey and Lindemann [32] provide a simulation of brain damage on a neural network architecture and offer evidence that different lesions to a same network can lead to different error distributions. We briefly review the various kinds of networks that have been proposed to simulate various arithmetical fact retrieval phenomena and we present a simple network designed to make some computational constraints apparent. Additionally, we replicate McCloskey and Lindemann’s [32] simulation by training 5 different artificial “subjects” and inflicting various types of damage upon each. Examination of the behaviour of our version of the network after different amounts of damage to its various connection blocks confirms that the error pattern may vary. These variations in the error patterns can be analyzed. The data may help to clarify the functioning of the network and give insight into the reasons why it produces several effects observed in human behaviour.
A COMPUTATIONAL HYPOTHESIS OF PROBABILITY INFERENCE IN NEURAL NETWORKS AND SOME RELATIONS TO PSYCHOLOGICAL MODELS
Authors: MYUNG I.J. , COLBERT C.M. , LEVY W.B.
Published: November 2004

In an attempt to understand the nature of information processing at the neuronal level and its relation to normal cognition at the behavioral level, this paper presents a neurally plausible computational theory of probability inference inspired by certain biological properties of neurons. The probability inference that the neural networks of this theory solve is the production of either probabilities or likelihoods associated with one set of events based on another set of events. The theory describes how a single neuron might create a probability in an analog fashion. It describes how certain optimal computational principles required for probability inference (e.g., Bayes rule) might be implemented at the neuronal level despite apparent limitations of the computational capacity of neurons. In fact, it is the fundamental properties of neurons that lead to the particular neuronal computation. Finally, this report attempts to connect this neural network theory to existing psychological models that assume Bayes inference schemes.
MAKING AND USING YOUR OWN COMPUTER GRAPHICS AND ANIMATIONS FOR SCIENCE EDUCATION: AN EXAMPLE -“VISUAL GENETICS”
Authors: DAY ALAN W. , DEAN ROBERT L.
Published: November 2004

This paper describes graphics-based teaching programs developed in genetics and points out to other educators how to create animated lessons to teach complex dynamic concepts in any area of science. Computer animations have proven to be very effective in teaching dynamic principles as well as illustrating static information.
PUTTING MANAGEMENT MODELS ON THE MANAGER’S DESKTOP
Authors: SILVERT WILLIAM
Published: November 2004

One of the greatest problems facing theoretical scientists and modellers is the difficulty of presenting results to managers in a form that can be understood and utilized by them while retaining as much as possible of the scientific content. Many managers have limited scientific expertise and they are often unfamiliar with theoretical approaches. They are also reluctant to share their decision-making responsibilities with scientists, who may not be familiar with all the factors they have to deal with. This often makes it difficult for scientific advisors to function effectively.

An alternative is to use expert systems technology to let managers access the scientific expertise relevant to the decision-making process without requiring direct personal interaction with scientific advisors. This is particularly appropriate for environmental management situations where managers in remote locations may not have easy access to scientists in relevant fields. We have therefore been developing a Decision Support System (DSS) as a tool for communicating scientific advice to managers. This paper addresses the general issues behind using Decision Support Systems in this way and discusses some of the problems involved.

Although a computer program cannot be expected to represent more than a fraction of the expertise of real scientists, the DSS approach appears to have several advantages; these include the ability to deliver a degree of expertise in remote and isolated regions, and, perhaps most important, a chance for managers to access scientific resources in a private environment which lets them explore various options without having to justify their eventual actions to scientists who may not fully appreciate all the pressures which bear on their decisions.
AN “ASYMPTOTIC FRACTAL” APPROACH TO THE MORPHOLOGY OF MALIGNANT CELL NUCLEI
Authors: LANDINI GABRIEL , RIPPIN JOHN W.
Published: November 2004

To investigate quantitatively nuclear membrane irregularity, 672 nuclei from 10 cases of oral cancer (squamous cell carcinoma) and normal cells from oral mucosa were studied in transmission electron micrographs. The nuclei were photographed at ×1400 magnification and transferred to computer memory (1 pixel=35 nm). The perimeter of the profiles was analysed using the “yardstick method” of fractal dimension estimation, and the log-log plot of ruler size vs. boundary length demonstrated that there exists a significant effect of resolution on length measurement. However, this effect seems to disappear at higher resolutions. As this observation is compatible with the concept of asymptotic fractal, we estimated the parameters c, L and Bm from the asymptotic fractal formula Br=Bm {1+(r/L)c}−1, where Br is the boundary length measured with a ruler of size r, Bm is the maximum boundary for r→0, L is a constant, and c=asymptotic fractal dimension minus topological dimension (D−Dt) for r→∞. Analyses of variance showed c to be significantly higher in the normal than malignant cases (P<0.001), but log(L) and Bm to be significantly higher in the malignant cases (P<0.001). A multivariate linear discrimination analysis on c, log(L) and Bm re-classified 76.6% of the cells correctly (84.8% of the normal and 67.5% of the tumor). Furthermore, this shows that asymptotic fractal analysis applied to nuclear profiles has great potential for shape quantification in diagnosis of oral cancer.
SIMULATION OF ENVIRONMENTALLY INDUCED GROWTH FORMS IN MARINE SESSILE ORGANISMS
Authors: KAANDORP JAAP A.
Published: November 2004

In marine sessile organisms (e.g. sponges and stony-corals), a distinction can be made in organisms that use filter-feeding, light or a combination of both, as a source of energy. In many of these organisms, growth takes place by the addition of layers of new material on top of the preceding growth stages that remain unchanged. The growth process of an organism that uses exclusively light and one that uses only filter-feeding for energy intake, are simulated using an iterative geometric construction in combination with, respectively, a light intensity function and a diffusion equation.
REACTION-FRONT DYNAMICS IN A+B→C WITH INITIALLY-SEPARATED REACTANTS
Authors: HAVLIN S. , ARAUJO M. , LARRALDE H. , SHEHTER A. , STANLEY H.E.
Published: November 2004

We review recent developments in the study of the diffusion reaction system of the type A+B→C in which the reactants are initially separated. We consider the case where the A and B particles are initially placed uniformly in Euclidean space at x>0 and x<0 respectively. We find that whereas for d≥2 a single scaling exponent characterizes the width of the reaction zone, a multiscaling approach is needed to describe the one-dimensional system. We also present analytical and numerical results for the reaction rate on fractals and percolation systems.
COMPUTER SIMULATIONS OF FRACTAL SURFACES: APPLICATION IN ADSORPTION
Authors: DOBRESCU GIANINA , RUSU M. , VASS M.
Published: November 2004

A computer program which is able to simulate adsorption on fractal surfaces was developed. The fractal surfaces are generated as Takagi surfaces. The computer program is based on a DLA-algorithm. Adsorption was simulated in different conditions:

1. equivalent active sites (homogeneous surfaces);

2. active sites with different adsorption probabilities; the probability associated with every active site is computed using a van der Waals potential.

Our simulation allows us to explore the actual structure of the gas-solid interface and to study the sensitivity to energetic disorder. The fractal dimension of gas-solid interface vs. adsorption coverage curves are computed.
FRACTAL ELECTRODEPOSITS: MORPHOLOGY, GROWTH DYNAMICS AND DIFFUSION-LIMITED RESPONSE FUNCTIONS
Authors: TRIGUEROS PEDRO PABLO , MACH JORDI , CLARET JOSEP , MAS FRANCESC , SAGUÉS FRANCESC
Published: November 2004

Fractal characterization of zinc electrodeposits obtained in a quasi two-dimensional film cell under suitable applied potential and zinc sulphate concentrations is reported. Our results show that these deposits are formed according to a Laplacian growth mode, and moreover, their self-similar fractal nature allows the generalization of the Cottrell law for diffusion-limited electrochemical processes occurring on these surfaces.
KINETIC ROUGHENING AND INTERACTING REACTING SPECIES: NONLINEAR ASPECTS
Authors: SOKOLOV I.M. , ARGYRAKIS P. , BLUMEN A.
Published: November 2004

We consider the A+B→0 reaction, in which particles interact through short-range forces. The analysis leads to expressions akin in form to those which describe kinetic roughening. In a situation in which particles are generated with a constant rate j0, their concentration n(t) grows as [Formula: see text] in d=1. Here the theoretical analysis predicts γ=1/5 and β=2/5, in very good agreement with direct Monte-Carlo simulations of the reaction-diffusion process.
A FRACTAL MODEL FOR SEISMICITY AT IZU-TOKAI REGION, CENTRAL JAPAN
Authors: BODRI B.
Published: November 2004

Fractal approach has been applied to investigate regional seismicity at the Izu peninsula—Tokai area, Central Japan. The frequency-magnitude distribution of earthquakes, distribution of epicenters, origin times of earthquakes, the fracture fault system in the region have been considered, and the fractal dimensions corresponding to them were calculated. A good correspondence in the fractal dimension values was found.

The frequency-magnitude distribution in the area shows a fractal dimension of 1.28, whilst D=1.15±0.18 is representative of the geometry of the distribution of earthquake epicenters. The fractal dimension of faults for the Izu peninsula is found to be 1.16±0.04, and in the whole Izu-Tokai region, values 1.1<D<1.3 are characteristic. The temporal distribution of earthquakes yields a fractal dimension of 0.51±0.03, which indicates a relatively weak clustering of events in time. Independent autocorrelation analysis also shows that the earthquakes in the area of study occur to a large extent statistically independent.

The general conclusion is that crustal deformation in the Izu-Tokai region occurs on a scale-invariant matrix faults. The behavior of the system is controlled by a single parameter, the fractal of dimension.
AN APPLICATION OF FRACTAL THEORY TO INFORMATION DISPLAY
Authors: KOIKE HIDEKI
Published: November 2004

This paper describes a fractal-based method for controlling information display. This method can be applied to information structures which are represented as trees, such as structured programs, UNIX directories, and so on. Its features are: (1) both local details near the focus of attention and major landmarks further away are displayed; (2) the total amount of information displayed is nearly constant whichever node a user focuses on; and (3) this amount is set flexibly.
ENTROPIC AND MULTIFRACTAL ANALYSIS OF DISORDERED MORPHOLOGIES
Authors: BEGHDADI A. , ANDRAUD C. , LAFAIT J. , PEIRO J. , PERREAU M.
Published: November 2004

We propose the configuration entropy as an efficient tool of characterization of the disorder of random morphologies and as a pertinent morphological parameter for describing the optical properties. When increasing the size of observation of an image, it undergoes a maximum at a characteristic length which is the optimum length at which the image must be observed to get the maximum information. When applied to computer simulated images, the configuration entropy is more powerful, less ambiguous and less sensitive to the finite size of images than the generalized fractal dimension.
EVALUATION OF FRACTAL DIMENSION MEASUREMENTS BY FREQUENCY ANALYSIS METHODS
Authors: AGUILAR MIGUEL , PANCORBO MANUEL , ANGUIANO ELOY
Published: November 2004

A study of the quality and accuracy of the methods, based on frequency analysis, for fractal characterization of surfaces is carried out. The study is based on computer simulation of fractal surfaces images and then a discussion of the mathematical algorithms used for computer generation of fractal surfaces is also made. The main conclusion is that the studies of fractal characterization by frequency analysis reported in previous papers as well as the conclusions about the performance of the different methods are doubtful and questionable. We propose new methods for frequency analysis that in some cases yield the more accurate results.
MULTIFRACTALITY OF GENERALIZED FIBONACCI PROFILES
Authors: FREITAS A.D. , COUTINHO S.
Published: November 2004

The multifractal properties of a class of one parameter generalized Fibonacci sequences are studied. This class of recursion relations, which is defined by an infinite set of sequences similar to the original Fibonacci’s one, appears for the first time in the study of the Ising model by the real space Migdal-Kadanoff renormalization group approach. The whole set of numbers generated by these equations, when properly arranged over the interval [0,1], gives the exact local magnetization profile of the Ising model on generalized hierarchical lattices at the critical temperature. This profile has a multifractal structure showing that an infinite set of exponents is required to describe how its singularities are distributed. The F(α)-function for the measure defined by the normalized profile is numerically obtained and analyzed. Each value of α characterizes the set of numbers generated by one sequence with arbitrary initial conditions. The exact lower (αmin) and upper (αmax) bounds of the spectra are analytically calculated. For a particular value of the parameter, the original Fibonacci sequence appears, generating a set of numbers diverging with the αmin exponent.
ANOMALOUS INTERFACE ROUGHENING: THE ROLE OF A GRADIENT IN THE DENSITY OF PINNING SITES
Authors: AMARAL L.A.N. , BARABÁSI A.-L. , BULDYREV S.V. , HAVLIN S. , STANLEY H.E.
Published: November 2004

We study the effect on interface roughening of a gradient ∇p in the density of pinning sites p. We identify a new correlation length, ξ, which is a function of ∇p: ξ~(∇p)−γ/α, where α=ν⊥/ν|| is the roughness exponent, and γ=ν⊥/(1+ν⊥). The exponents ν⊥ and ν|| characterize the transverse and longitudinal correlation lengths. To investigate the effect of ∇p on the scaling properties of the interface in (1+1) and (2+1) dimensions, we calculate the critical concentration, pc, and the exponents γ and α from which ν⊥ and ν|| can be determined. Our results are in qualitative agreement with some of the features of imbibition experiments.
THE ANISOTROPY OF ON-LATTICE SIMULATIONS OF AGGREGATE GROWTH
Authors: OTÁLORA FERMÍN , GARCÍA-RUIZ JUANMA
Published: November 2004

The origin of anisotropy in on-lattice simulations of cluster growth is investigated by quantifying the anisotropic behavior of the two processes involved in the simulation: transport and aggregation of nutrient particles. Three different anisotropic effects are described: anisotropic surface kinetics, anisotropic concentration profiles and anisotropic screening. The relevance of these sources of anisotropy in natural systems is discussed.
CHARACTERIZATION OF POROUS MEDIA WITH GEOMETRICAL MULTIFRACTALS
Authors: SAUCIER ANTOINE , MULLER JIRI
Published: November 2004

In a porous medium the local porosity often exhibits spatial variations. These variations can be characterized by a multifractal spectrum, as long as suitable scaling characteristics are present. We derive some of the properties of such geometrical multifractals, and discuss how the spatial distribution of a set is related to its multifractal spectrum.
FRACTAL ASPECTS OF INTERSTELLAR CLOUDS
Authors: ZIMMERMANN THOMAS , STUTZKI JÜRGEN
Published: November 2004

Interstellar matter consisting of gas and dust shows structures which appear to have self-similar projected shapes, similar to the properties of terrestrial clouds. Moreover, the completely different physics in these interstellar clouds reveals several additional self-similar/fractal aspects which are investigated by extensive astronomical observations, aiming especially at a better understanding of the processes of star formation which take place in interstellar molecular clouds.
ON THE FRACTAL STRUCTURE OF ELECTRON AVALANCHES
Authors: DONKÓ Z. , PÓCSIK I.
Published: November 2004

The motion of electrons in helium gas in the presence of a homogeneous external electric field was studied. Moving between the two electrodes, the electrons participate in elastic and inelastic collision processes with gas atoms. In ionizing collisions, secondary electrons are also created and in this way self-similar electron avalanches build up. The statistical distribution of the fractal dimension and electron multiplication of electron avalanches was obtained based on the simulation of a large number of electron avalanches. The fractal dimension shows a power-law dependence on electron multiplication with an exponent of ≈0.33.