bluuebunny/crossref_metadata_2025 huggingface dataset:
SCALING THEORY AND THE CLASSIFICATION OF PHASE TRANSITIONS
Authors: HILFER R.
Published: November 2004

The recent classification theory for phase transitions (R. Hilfer, Physica Scripta 44, 321 (1991)) and its relation with the foundations of statistical physics is reviewed. First it is outlined how Ehrenfests classification scheme can be generalized into a general thermodynamic classification theory for phase transitions. The classification theory implies scaling and multiscaling thereby eliminating the need to postulate the scaling hypothesis as a fourth law of thermodynamics. The new classification has also led to the discovery and distinction of nonequilibrium transitions within equilibrium statistical physics. Nonequilibrium phase transitions are distinguished from equilibrium transitions by orders less than unity and by the fact that equilibrium thermodynamics and statistical mechanics become inapplicable at the critical point. The latter fact requires a change in the Gibbs assumption underlying the canonical and grandcanonical ensembles in order to recover the thermodynamic description in the critical limit.
PHASE DIAGRAM OF THE FALICOV-KIMBALL MODEL WITH INFINITE-RANGE HOPPING
Authors: FARKAŠOVSKÝ PAVOL
Published: November 2004

We have studied the ground state properties of the Falicov-Kimball model with unconstrained hopping. It is shown that the model still behaves non-trivially, although it no longer depends on the actual lattice structure and dimensionality of the system. For arbitrary ion configurations with total number of ions Ni, we have been able to determine domains in the plane of the chemical potentials of electrons and ions where these ion configurations are ground states. The phase diagram of the model is discussed.
INFLUENCES OF THALLIUM-DOPING ON THE PHASE TRANSITION AND RAMAN SPECTRA OF BLUE MOLYBDENUM BRONZES IN CHARGE-DENSITY-WAVE STATE
Authors: TIAN MING-LIANG , TIAN DE-CHENG , ZHANG MING-SHENG , CHEN QIANG , LIN ZU-XUAN
Published: November 2004

Temperature dependencies of the Raman spectra of pure K 0.3 MoO 3 and thallium-doped K 0.15 Tl 0.15 MoO 3 blue bronzes are reported. The results showed that in pure bronze the commensurate domains separated by discommensurations occur below 100 K, perhaps as a result of the influence of the commensurate potentials of the undistorted alkaline sublattice. The disorder Tl-impurities may destroy the commensurate domains and lead to complete incommensuration in Tl-doped blue bronze below 100 K. The tremendous critical fluctuations and impurity-induced lack of long-range order of incommensurate CDW would lead to the spectral continuum or its disappearing. The weak softening of the amplitude mode is about 11%, which is similar to previous report. We were also the first to observe two strong new modes at about 76 cm −1 and 86 cm −1 in the distorted CDW state and attributed them to zone center excitations of the phonon branches at zone boundary due to CDW-induced collapse of the Brillouin zone at T p .
GROUND STATE PROPERTIES OF THE SIMPLIFIED HUBBARD MODEL
Authors: FARKASOVSKY PAVOL
Published: November 2004

We present the exact solution of the simplified Hubbard model in which only one kind of electrons can hop and this quantum mechanical hopping of electrons is assumed to be unconstrained. It is shown that the model still behaves non-trivially, although it no longer depends on the lattice structure and the dimensionality of the system. For this case we find: (i) a gap in the ground state energy always exists at the half-filled band point (n = 1), (ii) a preferred magnetic state at n = 1 and large U is a total spin singlet, (iii) U-dependence of the ground state energy has qualitatively the same form as one of the conventional Hubbard model with the (t2/U)-behavior at large U. A phase diagram of the model is discussed.
ELECTRON–PHONON MECHANISM OF SUPERCONDUCTIVITY IN THE TWO-BAND EMERY MODEL
Authors: CHAN MINH-TIEN , PLAKIDA N. M.
Published: November 2004

The electron–phonon mechanism of superconducting pairing in the two-band Emery model on a square lattice is considered. On the basis of the equation of motion the self-consistent system of equations for the matrix electron Green function is obtained. The dependence of the superconducting transition temperature T c on the concentration of holes is calculated. It is shown that due to the exclusion of double occupancy of copper sites the maximum T c occurs at the concentrations of holes n ≈ 0.8 and n ≈ 2.3, which correspond to the Van Hove singularities in copper and oxygen band, respectively.
TIME DEPENDENCE OF RESISTIVE TRANSITION OF EPITAXIAL GdBa2Cu3Oy SUPERCONDUCTING FILM IN PULSED MAGNETIC FIELD
Authors: XIAO-GUANG LI , HONGCHENG LI , YUHENG ZHANG
Published: November 2004

Broadening of resistive superconducting transition in an epitaxial GdBa2Cu3Oy, superconducting film below Tc was studied by the pulsed magnetic field technique. The results show that the transition in the field is not only broadened but also time-dependent. It is suggested that the time dependence of the broadening of resistive transition is mainly caused by flux motion.
FRACTIONAL QUANTUM HALL EFFECT AND CRYSTALLIZATION
Authors: BASU BANASRI
Published: November 2004

We have studied the possibility of formation of crystal structure in the case of fractional quantum Hall effect for ν<1/5.
THE HOPFIELD MODEL AS THE MINIMUM NOISE MODEL FOR NEURONS WITH VARIABLE FIRING STRENGTH
Authors: BASSIAS K.V. , FRANK B.
Published: November 2004

A “non-standard Hopfield” network of neurons with variable maximum firing strength ai is studied and a noise analysis is employed. It is shown that the requirement of minimum noise forces the solution with ai=1, ∀i, namely, the standard Hopfield model. The minimum noise is calculated.
DYNAMICAL PHASE TRANSITIONS ON COMB LATTICES
Authors: CASSI D. , REGINA S.
Published: November 2004

We study by analytical techniques the dynamical phase transition between recursive and transient regime induced on comb lattices by a topological bias. The critical exponents are expressed as functions of the intrinsic dimensions of these structures. In particular we show that, unlike what happens on Bethe lattices, it takes in general two different exponents to characterize the approach to the critical point from the recursive phase and from the transient one. These exponents depend respectively on the connectivity and on the spectral dimension.
FEYNMAN DIAGRAM EXPANSION IN THE BALANCE-EQUATION TRANSPORT THEORY
Authors: LEI X.L. , WU M.W.
Published: November 2004

In the balance-equation theory for hot-electron transport, the fact that electrons and phonons have different temperatures in the initial density matrix prevents one from directly invoking the conventional statistical Wick theorem to carry out a high-order perturbation analysis. Nevertheless, the well-known Feynman rules and diagram technique are demonstrated to be applicable to any order of the electron—impurity and electron—phonon interactions within the Keldysh Green’s function formalism of this theory.
ON THE VALIDITY OF MEAN-FIELD THEORY FOR ANYONS ON A LATTICE
Authors: OVCHINNIKOV A.A. , OVCHINNIKOV An. A.
Published: November 2004

We examine the validity of the mean-field approximation for anyons on a lattice at high density. The phase fluctuations for a large deviation from the Fermi statistics, in particular for the hard core bosons, are shown to be large. The importance of the phase fluctuations in different fermionic mean-field approaches for the antiferromagnetic Heisenberg model is stressed.
MULTIFRACTAL ELECTRONIC WAVE FUNCTIONS IN THE ANDERSON MODEL OF LOCALIZATION
Authors: SCHREIBER MICHAEL , GRUSSBACH HEIKO
Published: November 2004

Investigations of the multifractal properties of electronic wave functions in disordered samples are reviewed. The characteristic mass exponents of the multifractal measure, the generalized dimensions and the singularity spectra are discussed for typical cases. New results for large 3D systems are reported, suggesting that the multifractal properties at the mobility edge which separates localized and extended states are independent of the microscopic details of the model.
ANOMALOUS FERMIONIC OCCUPANCY FOR HIGH-Tc SUPERCONDUCTING LAYERED MATERIALS
Authors: CARMONA G. , MÉNDEZ-MORENO R. M. , OROZCO S. , ORTÍZ M. A. , MORENO M. , DE LLANO M. , AGUILERA-NAVARRO V. C.
Published: November 2004

Tighter-bound Cooper fermion pairs are obtained in a model with anomalous occupancy for fermions confined to an infinite slab mimicking the copper-oxide planes in cuprate superconductors. The model is applied to several typical high T c superconductors. T c values in this model are higher than those obtained with normal occupancy. Small but nonzero values for the anomalous occupancy parameter give a remarkably good description of the data.
STRUCTURES AND PROPERTIES OF F-DOPED BI-SYSTEM SUPERCONDUCTORS
Authors: GAO XIAOHUI , LI JIE , GAO DE , ZHENG GUODONG , GAO SAI
Published: November 2004

In this paper, the possibility of F entering the superconducting phase, its position and the structure properties of the superconductors, and the mechanism of superconductivity in F-doped Bi-systems are studied based on experimental and theoretical results. It has been found that, because the ΔT c is narrowed and [Formula: see text] raised, the T co of F-doped Bi-system superconductors increases obviously, with the highest T co at 118 K, that F has entered into the superconducting phase, that generally F can reduce the potential barrier of forming high-T c superconducting phase and improve the superconductivity of Bi-systems, but only if there exists certain amount of Pb in the system, and that with F-doping the weak linkage of superconductor is decreased, the flux pinning is enhanced, the carrier-hole concentration is increased, and the critical current is improved.
NEW 1222-TYPE LAYERED CUPRATES (Tl,M)Sr2(Nd,Ce)2Cu2Oz(M = Ti or Nb)
Authors: CHEN Z. Y. , SHENG Z. Z. , TANG Y. Q. , LI Y. F. , PEDERSON D. O.
Published: November 2004

New 1222-type layered cuprates (Tl,M)Sr 2 (Nd,Ce) 2 Cu 2 O z (M = Ti or Nb) have been successfully synthesized in the pure form and identified by powder X-ray diffraction analyses. The lattice parameters are a=3.847 Å and c=29.43 Å for ( Tl 0.8 Ti 0.2) Sr 2( Nd 0.75 Ce 0.25)2- Cu 2 O 9 and a=3.852 Å and c=29.45 Å for ( Tl 0.8 Nb 0.2) Sr 2( Nd 0.75 Ce 0.25)2 Cu 2 O 9. Resistance measurements showed that they me superconducting at about 40 K.
INTERNAL ORGANIZATION OF CLASSIFIER NETWORKS TRAINED BY BACKPROPAGATION
Authors: MICHAELS D. F.
Published: November 2004

Backpropagation is one of the most widely used methods for training multilayer neural networks, yet questions still exist regarding how the networks organize internally during (raining to represent the external training environment. This paper presents empirical measurements showing that feedforward networks, when trained on many separable and non-separable problems, learn a characteristic internal representation, herein called the Network Linear Transform (NLT), that is independent of: (a) the initial weights and cell biases, and (b) the number of hidden units. The internal decomposition (defined as the values of cell weights and biases) of the trained nets, however, is greatly dependent upon these quantities. For the case of orthogonal input patterns, the NLT captures a literal image of the training environment, while for linearly-independent and separable linearly-dependent training sets, the NLT: (a) captures characteristic features of the correct input patterns, (b) captures inverted versions of characteristic features of incorrect patterns, and (c) rejects features common to all pattern classes. For non-separable problems, the NLT captures statistical ensemble information about patterns in each training class. The hidden units act as difference detectors and thus convey information that distinguishes input patterns from one another. They separate the patterns into groups that are easily discriminated by the output cells. A linearized mathematical network model is developed that accurately reproduces weight matrices and cell responses for certain separable learning situations, and which supports the experimental findings given above.
PARALLEL ALGORITHM FOR COLOUR TEXTURE GENERATION USING THE RANDOM NEURAL NETWORK MODEL
Authors: ATALAY VOLKAN , GELENBE EROL
Published: November 2004

We propose a parallel algorithm for the generation of colour textures based upon the non-linear equations of the "multiple class random neural network model". A neuron is used to obtain the texture value of each pixel in the bit-map plane. Each neuron interacts with its immediate planar neighbours in order to obtain the texture for the whole plane. A model which uses at most 4(C2 + C) parameters for the whole network, where C is the number of colours, is proposed. Numerical iterations of the non-linear field equations of the neural network model, starting with a randomly generated image, are shown to produce textures having different desirable features such as granularity, inclination and randomness. The experimental evaluation shows that the random network provides good results, at a computational cost which is considerably less than that of other approaches such as Markov random fields.
COMPUTATIONAL ENVIRONMENTS FOR EXPLORING DYNAMICAL SYSTEMS
Authors: GUCKENHEIMER JOHN
Published: November 2004

Nonlinear dynamical-system models are ubiquitous throughout the sciences and engineering. Efficient computational analysis of specific dynamical systems is often a critical component for the successful completion of a research or design project. The enormous increase in the computational capability of desktop computers presents an opportunity for corresponding increases in our ability to explore dynamical models efficiently. Doing so requires that a suitable computational environment be established that gives the user interactive access to algorithms, graphical displays and data management tools. This paper is an overview of what such an environment might look like. The program kaos is a prototype that is oriented towards the computation of multiparameter bifurcation diagrams.
THE LOSS OF CHAOS IN A QUASIPERIODICALLY-FORCED NONLINEAR OSCILLATOR
Authors: KAPITANIAK TOMASZ
Published: November 2004

It has been shown that quasiperiodic perturbation stabilizes a period-doubling bifurcation point. This stabilization can lead to the loss of chaos in chaotic systems with this type of perturbation. An existence condition for the loss-of-chaos phenomenon based on Feigenbaum's universal properties of period doubling is proposed.
MODE LOCALIZATION DUE TO SYMMETRY-BREAKING NONLINEARITIES
Authors: PIERRE CHRISTOPHE , SHAW STEVEN W.
Published: November 2004

We present some ideas regarding the occurrence of mode localization in nonlinear structural systems. Preliminary analytical and numerical findings indicate that even if the linearized system has perfect periodicity, and thus cannot feature localized behavior, severe localization may occur in the nonlinear system when nonlinear terms break symmetry. These symmetry-breaking nonlinear terms play the same role as disorder does in nearly periodic linear systems.
BIFURCATION STRUCTURE OF SCALAR DIFFERENTIAL DELAYED EQUATIONS
Authors: MALTA C. P. , RAGAZZO C. GROTTA
Published: November 2004

We study periodic solutions of the equation [Formula: see text], with f(X) given by f1(X) = AX(1 − X) or f2(X) = πµ (1 − sin X), grouped in some sets characterized by different dominant frequencies. Numerical results with f(X) = f1(X) are given. One of these sets is shown to exhibit period-doubling cascade in the direction of both parameters A and τ. The other sets are shown to exhibit many other period-doubling cascades as τ is varied establishing a relation between the bifurcation structure within the sets. Furthermore we obtain a lower bound on A and µ for the existence of more complex dynamics. We conjecture that this fact is related to the violation of the so-called "negative-feedback condition."
SUFFICIENT CONDITIONS FOR THE EXISTENCE OF INVARIANT TORI IN MULTIDIMENSIONAL DYNAMICAL SYSTEMS
Authors: AFRAIMOVICH V. S. , ZHELEZNYAK A. L. , ZHELEZNYAK I. L.
Published: November 2004

A method for analyzing the existence of a multidimensional torus for certain systems of ordinary differential equations is proposed. Using this method, the existence of a multidimensional torus in one of such systems is analyzed. This system is a mathematical model of the dynamics of interacting structures within the drift hydrodynamical systems. The behavior of trajectories on the multidimensional torus is numerically investigated. The existence of two- and three-dimensional tori as well as strange attractors are considered.
SYNCHRONIZING CHAOS FROM ELECTRONIC PHASE-LOCKED LOOPS
Authors: ENDO TETSURO , CHUA LEON O.
Published: November 2004

This note presents the first experimental demonstration that two similar phase-locked loops driven by a common chaotic signal derived from a master phase-locked loop can be synchronized under some suitably chosen but robust range of system parameters. Experimental observations are qualitatively consistent with both computer simulations, and with the recent synchronization criterion due to Pecora and Carrol. The robustness of this synchronization scheme suggests the intriguing possibility of using chaos as the scrambling codes for spread spectrum communications.
GENERATING NONTRIVIAL LONG-RANGE CORRELATIONS AND 1/f SPECTRA BY REPLICATION AND MUTATION
Authors: LI WENTIAN
Published: November 2004

This paper aims at understanding the statistical features of nucleic acid sequences from the knowledge of the dynamical process that produces them. Two studies are carried out: first, mutual information function of the limiting sequences generated by simple sequence manipulation dynamics with replications and mutations are calculated numerically (sometimes analytically). It is shown that elongation and replication can easily produce long-range correlations. These long range correlations could be destroyed in various degrees by mutation in different sequence manipulation models. Second, mutual information functions for several human nucleic acids sequences are determined. It is observed that intron sequences (noncoding sequences) tend to have longer correlation lengths than exon sequences (protein-coding sequences).
THE DYNAMICS OF TWO PULSE-COUPLED RELAXATION OSCILLATORS
Authors: BRAILOVE ADAM A.
Published: November 2004

The dynamics of a pair of coupled integrate-and-fire oscillators is studied. Previous work by Mirollo and Strogatz is extended here to include the more realistic case in which the oscillators have different natural frequencies. It is shown that, given sufficient coupling, oscillators with arbitrary natural frequencies can always be made to synchronize. Furthermore, the condition necessary and sufficient for synchronization is determined. It is also shown that for any given set of parameter values there is a single periodic trajectory toward which all initial conditions are attracted: neither chaos nor quasiperiodicity is possible.
EXTRACTING SLOWLY VARYING SIGNALS FROM A CHAOTIC BACKGROUND
Authors: STARK JAROSLAV , ARUMUGAM BALAKUMAR V.
Published: November 2004

We consider the problem of extracting a small signal embedded in a stronger chaotic background. Under the assumption that the desired signal is relatively slowly varying we are able to devise an algorithm which in simple tests can recover the signal to a reasonable accuracy when the ratio of amplitudes of signal to chaotic background is as low as 10−10:1 when the dynamics of the background is known and 10−5:1 when the dynamics has to be estimated from the mixed signal itself. Potential applications include diagnostic monitoring of vibrating machinery as well as noise reduction in a variety of scenarios.
GLOBAL ANALYSIS BY CELL MAPPING
Authors: HSU C.S.
Published: November 2004

This paper deals with cell mapping methodology for global analysis of nonlinear dynamical systems. It serves a mixed set of purposes. It is basically a tutorial paper on cell mapping. But, it also reports on certain new developments in cell mapping and includes a summary of recent publications on the topic. Presented in Sec. 1–3 and 5 are the basic concepts and theory of cell mapping. Two types of cell-to-cell mapping are discussed, namely: simple cell mapping and generalized cell mapping. Once a dynamical system has been cast in the form of a cell mapping, one needs to extract the system behavior from the mapping. In Secs. 4 and 6, computation algorithms for simple cell mapping and generalized cell mapping are discussed in detail. Moreover, a workshop-type example is included to guide the reader if he wishes to gain a working knowledge of the methodology.

The new developments presented in the paper include an algorithm for processing simple cell mappings and a theory of subdomain-to-subdomain global transient analysis of generalized cell mapping. These are reported in Secs. 4–6. Listed in the last section are publications on cell mapping, including applications in many rather diversified areas of dynamics. Hopefully, the breadth of the examples of application will indicate the potential of the cell mapping method.
EXPERIMENTAL EVIDENCE OF DIFFUSIVE DYNAMICS AND “RANDOM WALKING” IN A SIMPLE DETERMINISTIC MECHANICAL SYSTEM: THE SHAKEN PENDULUM
Authors: BAYLY PHILIP V. , VIRGIN LAWRANCE N.
Published: November 2004

An experimental model of a simple pendulum, harmonically shaken, displays chaotic dynamics. Moreover, in strongly excited chaotic regimes the time series of total angular displacement, which is rarely examined, wanders unboundedly, displaying a power spectrum which falls off as 1/fα over several decades. This behavior corresponds to deterministic diffusion, which has been found in simulations of nonlinear maps with periodic translational symmetry. The displacement time series obtained by sampling the pendulum displacement once per cycle is self-affine and quantitatively similar to Brownian motion.
THE "COCOON" BIFURCATIONS IN THREE-DIMENSONAL SYSTEMS WITH TWO FIXED POINTS
Authors: LAU YUN-TUNG
Published: November 2004

We use a geometric approach to explore the dynamical structures of three-dimensional systems with two fixed points. In particular, we study the "cocoon" bifurcation, which is a series of global and local bifurcations that create an infinite number of heteroclinic orbits (which trace out a cocoon-like tangle in space). We introduce a symbolic dynamics to the intersections of a cross-sectional plane with the manifolds of the fixed points. A one-parameter system relevant to the travelling-wave solution of the Kuramoto–Sivashinsky equation is employed to illustrate this approach. The cocoon bifurcation begins with a rapidly converging sequence of heteroclinic bifurcations (principal sequence), each of which generates a pair of heteroclinic orbits and two new pieces of the two-dimensional manifolds. These bifurcations and the manifold structures are also observed with the time delay function of chaotic scattering. At the limit of the principal sequence, a saddle-node bifurcation occurs, followed by a period doubling cascade, which destroys the elliptical orbit and results in a hyperbolic invariant set. Other heteroclinic bifurcations not in the principal sequence are responsible for the folding and eventually the fractal structures of the two-dimensional manifolds. The cocoon bifurcation is completed when all intersections of the two-dimensional manifolds are transverse. The structurally stable system after the cocoon bifurcation contains a hyperbolic invariant set (a horseshoe) imbedded in two fractal sets of the two-dimensional manifolds. All three sets have the same fractal dimension. The cocoon bifurcation is a route to fully developed chaotic scattering. After a prospective effect, called manifold reconnection, the system undergoes a secondary cocoon bifurcation. Then the system becomes a hyperbolic invariant set that is characterized by a full shift of six symbols and is imbedded in two fractal sets of two-dimensional manifolds. Higher order cocoon bifurcations may become overlapped with the homoclinic bifurcation. These results are general and do not depend on the symmetry of the system. For a physical system represented by the dynamical system, it is conjectured that the structurally stable window after the cocoon bifurcation contains the physically most probable state.
NEW TYPE OF STRANGE ATTRACTOR FROM A GEOMETRIC MODEL OF CHUA'S CIRCUIT
Authors: BELYKH V. N. , CHUA L. O.
Published: November 2004

We present a new type of strange attractors generated by an odd-symmetric three-dimensional vector field with a saddle-focus having two homoclinic orbits at the origin. This type of attractors is intimately related to the double scroll. We present the mathematical properties which prove rigorously the chaotic nature of this strange attractor to be different from that of a Lorenz-type attractor or a quasiattractor.

In particular, we proved that for certain nonempty intervals of parameters, our two-dimensional map has a strange attractor with no stable orbits. Unlike other known attractors, this strange attractor contains not only a Cantor set structure of hyperbolic points typical of horseshoe maps, but also unstable points (i.e., stable in reverse time). This implies that the points from the stable manifolds of the hyperbolic points must necessarily attract the unstable points.
PROVING PROPERTIES OF RULE-BASED SYSTEMS
Authors: WALDINGER RICHARD J. , STICKEL MARK E.
Published: November 2004

Rule-based systems are being applied to tasks of increasing responsibility. Deductive methods are being applied to their validation, to detect flaws in these systems and to enable us to use them with more confidence.

Each system of rules is encoded as a set of axioms that define the system theory. The operation of the rule language and information about the subject domain are also described in the system theory. Validation tasks, such as establishing termination, unreachability, or consistency, or verifying properties of the system, are all phrased as conjectures. If we succeed in establishing the validity of the conjecture in the system theory, we have carried out the corresponding validation task.

If the proof is restricted to be sufficiently constructive, we may extract from it information other than a simple yes/no answer. For example, we may obtain a description of a situation in which an error or anomaly may occur.

A method for the gradual formulation of specifications based on the attempted proof of a series of conjectures has been found to be suitable for rule-based systems. Such a specification can serve as the basis for a reengineering of the system using conventional software technology.

Validation conjectures are proved or disproved by a new theorem-proving system, SNARK, which implements (nonclausal) resolution and paramodulation, an optional constructive restriction, and some facilities for proof by induction. The system has already been applied to prove properties of a number of simple rule-based systems.
ON THE POWER OF QUERY-INDEPENDENT COMPILATION
Authors: HAN JIA WEI
Published: November 2004

Recursive query processing techniques can be classified into three categories: interpretation, query-dependent compilation and query-independent compilation. Query-dependent compilation compiles IDB (Intensional Data Base) programs based on possible query instantiations into query-specific programs, while query-independent compilation compiles IDB programs into query-independent and easily analyzable relational expressions. Previous studies show that linear recursions can be query-independently compiled into highly regular forms. This study analyzes the power of query-independent compilation and shows that (i) query-independent compilation captures more binding information than other methods for irregular linear recursions; (ii) the compilation provides succinct information for selection of efficient query processing methods; and (iii) it facilitates constraint-based processing of complex queries. Finally, query-independent compilation can be applied to more complex recursions as well.
RANDOMIZATION YIELDS SIMPLE O(n log⋆ n) ALGORITHMS FOR DIFFICULT Ω(n) PROBLEMS
Authors: DEVILLERS OLIVIER
Published: November 2004

We use here the results on the influence graph1 to adapt them for particular cases where additional information is available. In some cases, it is possible to improve the expected randomized complexity of algorithms from O(n log n) to O(n log ⋆ n). This technique applies in the following applications: triangulation of a simple polygon, skeleton of a simple polygon, Delaunay triangulation of points knowing the EMST (euclidean minimum spanning tree).
SIMPLE ALGORITHMS FOR ENUMERATING INTERPOINT DISTANCES AND FINDING k NEAREST NEIGHBORS
Authors: DICKERSON MATTHEW T. , DRYSDALE R.L. SCOT , SACK JÖRG-RÜDIGER
Published: November 2004

We present an O(n log n+k log k) time and O(n+k) space algorithm which takes as input a set of n points in the plane and enumerates the k smallest distances between pairs of points in nondecreasing order. We also present an O(n log n+kn log k) solution to the problem of finding the k nearest neighbors for each of n points. Both algorithms are conceptually very simple, are easy to implement, and are based on a common data structure: the Delaunay triangulation. Variants of the algorithms work for any convex distance function metric.
BOUNDED COCYCLES AND COMBINGS OF GROUPS
Authors: GERSTEN S.M.
Published: November 2004

We adopt the notion of combability of groups defined in [12]. An example is given of a (bi-)combable group which is not residually finite. Two of the eight 3-dimensional geometries, [Formula: see text] and ℍ2×ℝ, are quasiisometric. Seifert fibred manifolds over hyperbolic orbifolds have bicombable fundamental groups. Every combable group satisfies an exponential isoperimetric inequality.
SIMPLE ORDERINGS FOR FREE PARTIALLY COMMUTATIVE GROUPS
Authors: DUCHAMP GÉRARD , THIBON JEAN-YVES
Published: November 2004

We present a method for ordering free partially commutative groups, leading to a simple comparison algorithm.

Résumé: Nous présentons une méthode pour ordonner les groupes partiellement commutatifs libres. Cette méthode conduit a un algorithme de comparaison particulièrement simple.
FUNDAMENTAL AND SECOND-ORDER SOLITION TRANSMISSION IN NONLINEAR DIRECTIONAL FIBER COUPLERS
Authors: PENG GANG-DING , ANKIEWICZ ADRIAN
Published: November 2004

Transmission characteristics of first-order and second-order solitons propagating through a nonlinear optical fiber coupler are investigated by analysing the coupled nonlinear Schrödinger equations (NLSEs). We show that it is most advantageous to use fundamental solitions to make an ideal optical switch which can be used in multiplexing and/or demultiplexing soliton signals from different sources, and that such a switch can have a high switching efficiency and intact soliton output. Also, we have analyzed the relation between critical power of a soliton switch and that of a cw switch, and have given the soliton “critical energy” in an explicit form in terms of the physical parameters. Further, we give evidence to show that soliton bound-states and different solitons can be generated through soliton conversion in a nonlinear coupler.
SIZE DEPENDENCE OF χ(3) IN NONLOCAL OPTICAL MEDIA: FRENKEL EXCITONS IN A PERIODIC CHAIN
Authors: ISHIHARA HAJIME , CHO KIKUO
Published: November 2004

For the discussion of the size dependence of the third-order nonlinear susceptibility χ(3) for confined electronic systems, the result of numerical study is given for an exactly soluble model of noninteracting Frenkel excitons in a periodic chain. The case of pump-probe type nonlinear effect is explicitly treated in the long-wavelength approximation, and Im [χ(3)] is evaluated as a function of chain size N, transfer energy b, and damping constants. For a given value of b(N), there is an enhancement of χ(3) with increasing value of N(b), followed by a saturation behavior. The range of the enhancement is determined by the damping constants. This provides a consistent view of the size and transfer dependence of χ(3), its saturation behavior, and the previously discussed cancellation problem.
OPTICAL POWER TRANSFER OF SINGLE-MODE LASER BEAMS THROUGH DISTORTING MEDIA USING A SEMILINEAR PHASE CONJUGATE MIRROR
Authors: JAATINEN ESA , LUTHER-DAVIES BARRY
Published: November 2004

We report experiments on the use of a semilinear phase-conjugate mirror to transfer single-mode laser beams through distorting media. Calculations using a 1-D model show that in optimum circumstances, up to 90% of the input power can be transferred to the system output whilst experimentally 23% power transfer has been observed limited by the absorption and gain in our Barium Titanate crystal. We have also studied seeding the semilinear mirror with a separate beam as a means of starting its oscillation in conditions where high power transfer efficiency is required and investigated regions of bistability in the output which also occur in this regime.
FUNDAMENTALS OF PARAMETRIC INTERACTION AND PHASE CONJUGATION
Authors: HSU HSIUNG
Published: November 2004

Parametric interactions are excited by reactive (imaginary) interaction energy. When the scattering involves backward traveling-waves, the interaction will exhibit phase conjugation characteristics. There are significant differences between forward and backward phase conjugation processes.
KB/RMS: AN INTELLIGENT ASSISTANT FOR REQUIREMENT DEFINITION
Authors: BINDER ROBERT V. , TSAI JEFFREY J. P.
Published: November 2004

In this paper, we present a conceptual framework and a system model for an intelligent assistant for requirement definition, KB/RMS. The requirement definition process is characterized by the Requirement Context Model. Informal and formal methods for requirement definition are considered in the light of this model, which serves as the logical schema for the KB/RMS database. We summarize conventional and knowledge-based system support for requirement definition. The use of natural language processing, a semantic model of the problem and solution spaces, domain and technology models, inference driven augmentation, validation, and verification of the semantic model is discussed. Finally, we present the production of design representations from the augmented semantic model.
TOOLS FOR EXPERIENTIAL RECOGNITION
Authors: LIGOMENIDES PANOS A.
Published: November 2004

Our objective in the interactive formulation of the "formal description schema - fds" model is the modeling of the prototypical, i.e. the subjective, perceptual ability of a human "expert", the ultimate human or robotic decision maker. In this paper, we present our fds-approach and methodology for solving the problem of modeling and exercising perceptual recognition [3–6]. We limit our discussion to one-dimensional variational profiles. We view the fds-model as a two-stage procedural model. Concerning the "early" (pre-attentive) recognition stage, we define the "structural identity of a k-norm class, k∈K" — SkID — as a tool for quick shadowing of sensory data and positioning instantiations of sufficient resemblance to interactively pre-defined spatio–temporal norm classes. Attentive recognition tools follow for assessing conformity of SkID-pointed occurrences.
DISTRIBUTED OBJECT MANAGEMENT
Authors: MANOLA FRANK , HEILER SANDRA , GEORGAKOPOULOS DIMITRIOS , HORNICK MARK , BRODIE MICHAEL
Published: November 2004

Future information processing environments will consist of a vast network of heterogeneous, autonomous, and distributed computing resources, including computers (from mainframe to personal), information-intensive applications, and data (files and databases). A key challenge in this environment is providing capabilities for combining this varied collection of resources into an integrated distributed system, allowing resources to be flexibly combined, and their activities coordinated, to address challenging new information processing requirements.

In this paper, we describe the concept of distributed object management, and identify its role in the development of these open, interoperable systems. We identify the key aspects of system architectures supporting distributed object management, and describe specific elements of a distributed object management system being developed at GTE Laboratories.
PLANNING AND REACTING ACROSS SUPERVENIENT LEVELS OF REPRESENTATION
Authors: SPECTOR LEE , HENDLER JAMES
Published: November 2004

For intelligent systems to interact with external agents and changing domains, they must be able to perceive and to affect their environments while computing long term projection (planning) of future states. This paper describes and demonstrates the supervenience architecture, a multilevel architecture for integrating planning and reacting in complex, dynamic environments. We briefly review the underlying concept of supervenience, a form of abstraction with affinities both to abstraction in AI planning systems, and to knowledge-partitioning schemes in hierarchical control systems. We show how this concept can be distilled into a strong constraint on the design of dynamic-world planning systems. We then describe the supervenience architecture and an implementation of the architecture called APE (for Abstraction-Partitioned Evaluator). The application of APE to the HomeBot domain is used to demonstrate the capabilities of the architecture.
TURAEV-VIRO AND KAUFFMAN-LINS INVARIANTS FOR 3-MANIFOLDS COINCIDE
Authors: PIUNIKHIN SERGEY
Published: November 2004

The presentation of link polynomials, arising from representations of quantum group SLq(2) by SLq(2)-spin networks is given. The explicit form of cabling formula for these polynomials is written. The connection between 6j-symbols in q-spin network theory and Rakah-Wigner q-6j-symbols is shown. The Kauffman's hypothesis about coincidence of his 3-manifold invariants and Turaev-Viro invariants for 3-manifolds is proved.
PLANAR GENERALIZATIONS OF THE YANG-BAXTER EQUATION AND THEIR SKEINS
Authors: CARTER J. SCOTT , SAITO MASAHICO
Published: November 2004

We solve the planar generalizations of the Yang-Baxter equation using Kauffman's bracket methods. These solutions are applied to get representations of certain Coxeter groups that are quotients of generalized braid groups.
GEOMETRIC PROPERTIES OF STRONG FUSION
Authors: KAISER UWE
Published: November 2004

We prove that a certain geometric construction on links in the 3-sphere preserves the properties: non-trivial, non-split, non-boundary.
THE CONFRONTATION BETWEEN GENERAL RELATIVITY AND EXPERIMENT: A 1992 UPDATE
Authors: WILL CLIFFORD M.
Published: November 2004

The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein’s equivalence principle is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Tests of general relativity have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected to half a percent using the binary pulsar, and new binary pulsar systems promise further improvements. The status of the “fifth force” is discussed, along with the frontiers of experimental relativity, including proposals for testing relativistic gravity with advanced technology and spacecraft.
PHYSICAL INTERPRETATION OF BLACK HOLE EVAPORATION AS A VACUUM INSTABILITY
Authors: PARENTANI R. , BROUT R.
Published: November 2004

Using tunneling concepts which account for particle production in the cases of an accelerated detector and a static electric Field in Minkowski space, the more elusive case of black hole evaporation is analyzed in terms of a detailed tunneling mechanism. For the case of the incipient black hole (collapsing star) Hawking’s “heuristic” picture in terms of pair creation, wherein one member crosses the horizon to fall into the singularity as the other is emitted to infinity, is established. The inception of tunneling is due to the motion of the star’s surface, but its completion concerns traversal of the horizon, thereby reconciling varying schools of thought concerning this problem.
MODELS OF CHAOTIC INFLATION
Authors: GOTTLÖBER S. , MÜLLER V. , SCHMIDT H.-J. , STAROBINSKY A.A.
Published: November 2004

A review of inflationary cosmological models from a geometrical point of view is made. Equivalence theorems relate different models and may be used to reduce them to a canonical form: the Einstein gravity minimally interacting with a number of coupled scalar fields (generally, coupling appears in kinetic terms, too). Double inflation appearing in the fourth-order gravity with a scalar field is considered. Some results on the attractor property of the de Sitter (inflationary) stage in various models are presented.
UPDATED REVIEW OF SOLAR MODELS AND SOLAR NEUTRINO EXPERIMENTS
Authors: MORRISON DOUGLAS R.O.
Published: November 2004

The Conventional Wisdom that there is a Solar Neutrino Problem and that New Physics is required, is examined. The various solar evolutionary models, (or SSM), are described and in particular the four new 1992 papers. While the evolutionary models are generally robust, there are important assumptions and uncertainties (screening, nuclear reaction rates, etc.) which mean that the errors cannot be small. Diffusion in the Sun is expected to be significant but so far there is no calculation which includes all types of diffusion, especially turbulent diffusion. The new and important helioseismological results are shown to to be in agreement with some of the SSM calculations. The experimental results are beginning to be not inconsistent with the SSM calculations. Kamiokande is consistent with SSM calculations except for one with rather small errors. The new GALLEX result is in agreement with all SSM calculations within 1.3 to 2 standard deviations. The 1990 SAGE I experiment is shown to have no evidence of solar neutrinos and is inconsistent with all SSM calculations and with GALLEX. However the new 1991 SAGE II experiment finds neutrino rates not inconsistent with SSM calculations. The Chlorine experiment is significantly below SSM calculations and is inconsistent with Kamiokande. In particular the Chlorine claim that there is a variation of the solar neutrino flux with the inverse of the sunspot activity, which shows a correlation of five standard deviation significance, is in contradiction with the results of the Kamiokande experiment which finds no variation of the solar neutrino flux with time. The overall conclusion is that there is no compelling evidence for a Solar Neutrino Problem or need for New Physics. However the neutrinos could still have masses and further experiments with higher statistics are essential as they are one of the rare ways of studying this low mass region. Thus the Solar Neutrino Problem is becoming a Neutrino Mass Quest.
ON THE UNIVERSAL CHARACTER OF THE LARGE SCALE STRUCTURE OF THE UNIVERSE
Authors: DEMIAŃSKI MAREK , DOROSHKEVICH ANDREJ G.
Published: November 2004

We review different theories on the formation of the large scale structure of the Universe. Special emphasis is put on the theory of inertial instability. We show that, for a large class of initial spectra, the resulting two point correlation functions are similar. We also discuss the adhesion theory which uses the Burgers equation, Navier-Stokes equation or coagulation process. We review the Zeldovich theory of gravitational instability and discuss the internal structure of pancakes. Finally, we discuss the role of the velocity potential in determining the global characteristics of large scale structure (distribution of caustics, scale of voids, etc.). In the last section, we list the main unsolved problems and the main successes of the theory of formation of large scale structure.
METRIC FROM NONMETRIC ACTION OF GRAVITY
Authors: KAMIMURA KIYOSHI , MAKITA SHINOBU , FUKUYAMA TAKESHI
Published: November 2004

The action of general relativity proposed by Capovilla, Jacobson and Dell is written in terms of SO(3) gauge fields and gives Ashtekar's constraints for Einstein gravity. However, it does not depend on the spacetime metric nor its signature explicitly. We discuss how the spacetime metric is introduced from algebraic relations of the constraints and the form of the Hamiltonian by focusing our attention on the signature factor. The system describes both Euclidean and Lorentzian metrics depending on reality assignments of the gauge connections. That is, Euclidean metrics arise from the real gauge fields. On the other hand, self-duality of the gauge fields, which is well known in the Ashtekar formalism, is derived in this theory from the consistency condition of the Lorentzian metric. We also show that the metric so determined is equivalent to that given by Urbantke, which is usually accepted as a definition of the metric for this system.
ON THE DIPOLE ANISOTROPY OF THE COSMIC BACKGROUND RADIATION AND THE INTERGALACTIC MEDIUM
Authors: MELCHIORRI F. , TANZILLI P.E.
Published: November 2004

COBE has provided preliminary results on the spectral distribution of both Cosmic Background Radiation (CBR) brightness and dipole anisotropy. We combine these data in order to compare COBRA results with those of COBE and to obtain more stringent upper limits to CBR spectral distortions. The possibility of having detected extragalactic diffuse lines is discussed.
NUCLEAR PHYSICS OF DARK MATTER DETECTION
Authors: ENGEL J. , PITTEL S. , VOGEL P.
Published: November 2004

We describe the elastic scattering of weakly interacting dark matter particles from nuclei, with laboratory detection in mind. We focus on the lightest neutralino (a neutral fermion predicted by supersymmetry) as a likely candidate and discuss the physics needed to calculate its elastic scattering cross section and interpret experimental results. Particular emphasis is placed on a proper description of the structure of the proposed detector nuclei. We include a brief discussion of expected count rates in some detectors.
MASSIVE GLUONS AND QUARK GLUON PLASMA SIGNATURES
Authors: BIRÓ TAMÁS S.
Published: November 2004

The evolution of the physical picture of the quark gluon plasma from an ideal gas to a complicated interacting system is reviewed. Recent calculations of quark gluon plasma signatures are discussed which consider a nonvanishing in-medium gluon mass.
CONTRIBUTION OF ANGULAR MOMENTUM DEPENDENT FORCES TO THE HYPERFINE STRUCTURE OF DEUTERIUM
Authors: AZAM SIKANDAR
Published: November 2004

All realistic modern nucleon–nucleon potentials contain terms which are linear and/or quadratic in angular momentum (L) such as L · S and L2 etc. These L-dependent terms contribute to the magnetic moment of the deuteron and to the hyperfine structure (hfs) of deuterium. We perform calculations with some detail with regard to the contribution of the L-dependent forces to the hfs of deuterium. We find that their contribution is quite substantial and sensitive to the choice of the potential.
AN INTRODUCTION TO THE QUARK MODEL FOR BARYONS
Authors: Isgur Nathan
Published: November 2004

Understanding the underlying quark and gluon structure of the nucleons is not only a fundamental objective in its own right, but also an essential first step in providing a basis within QCD for nuclear physics. In this article I present a pedagogical introduction to a simple but very successful nonrelativistic constituent quark model for baryons.