bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating diverse ERP systems: a case study
Authors: Alshawi Sarmad , Themistocleous Marinos , Almadani Rashid
Published: November 2004

Enterprise resource planning (ERP) went through many development cycles since its beginning in the 1970s until it established itself as a backbone of most major enterprises in the world. In spite of its countless advantages, most ERP implementations require heavy customisation to achieve their proclaimed advantages. This paper represents an endeavour to investigate, through a case study, the feasibility of minimising the heavy customisation required by most ERP implementations by selecting the best modules from each vendor and integrating them using enterprise application integration technologies, to form one (integrated) system. In doing so, the paper provides a description of a way to implement a suggested integrated solution, as well as a discussion of how minimising customisation enables enterprises to upgrade their ERP software effortlessly and cost‐effectively.
LOCALLY ACTIVATED NEURAL NETWORKS AND STABLE NEURAL CONTROLLER DESIGN FOR NONLINEAR DYNAMIC SYSTEMS
Authors: KIM HYO-GYU , OH SE-YOUNG
Published: November 2004

A stable neural control scheme using a locally activated neural network has been proposed for a class of nonlinear dynamic systems. The locally activated neural network, for a given input, essentially selects a small subset of the network hidden nodes for output computation using the CMAC-like content addressing mechanism. This network aims to maintain local representations of the system dynamics. Thus, the global control performance in the concerned state space is achieved by the cooperation of many local control efforts and furthermore, real-time control can be facilitated because only a small sized network is involved to control and learn at any given time. The proposed control scheme is composed of two stages: (1) prediction error based learning in which the network attempts to learn the nonlinear basis functions of the plant inverse dynamics by a modified backpropagation learning rule; and (2) tracking error based learning in which the network weights are further fine-tuned using the basis set obtained in (1). This basis set spans the locally partitioned vector space of the system inverse dynamics when the prediction error based learning is achieved within a prescribed error tolerance. For uniform stability, the sliding mode control is introduced as a safety mechanism when the network has not sufficiently learned the plant dynamics yet. With suitable assumptions on the controlled plant, global stability and tracking error convergence proof has been given. Finally, the proposed control scheme is verified with computer simulation.
USE OF MULTILAYER FEEDFORWARD NEURAL NETS AS A DISPLAY METHOD FOR MULTIDIMENSIONAL DISTRIBUTIONS
Authors: GARRIDO LLUIS , GAITAN VICENS , SERRA-RICART MIQUEL , CALBET XAVIER
Published: November 2004

We present a new method based on multilayer feedforward neural nets for displaying an n-dimensional distribution in a projected space of 1, 2 or 3 dimensions. A fully nonlinear net with several hidden layers is used. Efficient learning is achieved using multi-seed backpropagation. As a principal component analysis (PCA), the proposed method is useful for extracting information on the structure of the data set, but unlike the PCA, the transformation between the original distribution and the projected one is not restricted to be linear. Artificial examples and a real application are presented in order to show the reliability and potential of the method.
REMOTE SENSING OPERATIONS
Authors: BADRAN FOUAD , MEJIA CARLOS , THIRIA SYLVIE , CREPON MICHEL
Published: November 2004

We show that Neural Networks can efficiently model multivalued transfer functions. We propose a method related to conditional density approximation p(y/x) and test the validity of the approach on a remote sensing problem.
COUPLING CHIRAL BOSONS TO GRAVITY
Authors: BRAGA NELSON R. F. , WOTZASEK CLOVIS
Published: November 2004

The chiral boson actions of Floreanini and Jackiw (FJ), and of McClain, Wu and Yu (MWY) have recently been shown to be different representations of the same chiral boson theory. MWY displays manifest covariance and also a (gauge) symmetry that is hidden in the FJ side, which, on the other hand, displays the physical spectrum in a simpler manner. We make use of the manifest covariance of the MWY chiral boson representation to couple it to background gravity showing explicitly the equivalence with the previous results for the FJ representation.
WEYL NON-ABELIAN GAUGE FIELD
Authors: BARBASHOV B. M. , PESTOV A. B.
Published: November 2004

It is shown that the congruent transference introduced by Weyl in 1921 defines a non-Abelian gauge field. The simplest gauge-invariant equations are proposed for this field. Its relation with the Riemann–Cartan geometry is also discussed.
SIGNAL OF QUARK SUBSTRUCTURE IN HADRONIC INTERACTIONS AT SMALL SCATTERING ANGLES
Authors: CAO Z. , HE Y. D.
Published: November 2004

We explore the possibility of searching for signals of quark substructure in hadronic interactions at small scattering angles. Incorporating the four-fermion contact interaction due to scatterings between constituents of quarks in the lowest order QCD formalism, we find a deviation in the jet inclusive cross-sections at small scattering angles from the prediction by standard model. This strategy can be used to look for the compositeness of quarks at 1016 eV by analyzing cosmic ray double-core γ-family data.
ON TARGET SPACE DUALITY IN p-BRANES
Authors: PERCACCI R. , SEZGIN E.
Published: November 2004

We study the target space duality transformations in p-branes as transformations which mix the world volume field equations with Bianchi identities. We consider an (m+p+1)-dimensional space-time with p+1 dimensions compactified, and a particular form of the background fields. We find that while a GL (2) = SL (2) × R group is realized when m = 0, only a two-parameter group is realized when m > 0.
SCHWINGER–DYSON EQUATIONS AND CHIRAL SYMMETRY BREAKING IN 2-D INDUCED GRAVITY
Authors: ELIZALDE E. , ODINTSOV S. D. , ROMEO A. , SHIL'NOV YU. I.
Published: November 2004

The Schwinger–Dyson equations in the ladder approximation for 2-D induced gravity coupled to fermions on a flat background are obtained in conformal gauge. A numerical study of these equations shows the possibility of chiral symmetry breaking in this theory.
STRATEGIES FOR PROBING CP-PROPERTIES IN THE TOP QUARK SYSTEM
Authors: YUAN C.-P.
Published: November 2004

We discuss strategies for probing CP-properties in the top quark system in electron and hadron collisions. The magnitudes of CP-violation effects predicted by various models are reviewed. The potential of various current and future colliders in measuring the CP-asymmetry associated with the productions and/or decays of the top quarks is also discussed.
A NONPERTURBATIVE, SCHWINGER–DYSON EQUATION ANALYSIS OF QUARK MASSES AND MIXINGS IN A MODEL WITH QCD AND HIGGS INTERACTIONS
Authors: SMITH LESLEY L. , JAIN PANKAJ , MCKAY DOUGLAS W.
Published: November 2004

The Schwinger–Dyson equation for the quark self-energy is solved in the quenched ladder approximation for several cases of one- and two-quark generations. The exchanges of standard model gluons and Higgs bosons are taken into account. It is found that Higgs boson exchange dominates the quark self-energy in the uv region for sufficiently large input quark masses (> 75 GeV ), causing the running quark propagator mass to increase with energy scale. The running of the quark mixing angles is also considered. No running of the quark mixing angles is found for input quark masses up to and including 500 GeV.
COMPOSITE OPERATORS AS INTEGRATION VARIABLES IN BEREZIN INTEGRALS
Authors: DE FRANCESCHI G. , PALUMBO F.
Published: November 2004

We define nonlinear changes of variables in Berezin integrals as new integration variables of homogeneous polynomials of the defining elements in the Grassmann algebra. We perform such a change of variables in the partition function of QCD by introducing as integration variables cubic and quadratic polynomials of the quark field, with the quantum numbers of the nucleon and the meson respectively, and we suggest a perturbative scheme using these these functions as free states.
PROTON LIFETIME AND SMOLUCHOWSKI EQUATION
Authors: SILVA P.R.
Published: November 2004

We present a Smoluchowski-like equation for subnuclear reactions which could be applied to both proton and muon decays. Combined with the Heisenberg uncertainty principle, this phenomenological theory gives the known functional dependence of the proton (muon) lifetimes on mp, Mx; (mμ, Mw), where mp(mμ) are proton (μ meson) rest masses and Mx(Mw) are the threshold masses for the electroweak/strong (electroweak) forces unification. The stationary wave function of the reactions is also obtained.
LIGHT GLUINOS AND $\Gamma \left( {Z \to b\bar b} \right)$
Authors: CLAVELLI L.
Published: November 2004

We discuss the anomaly in the b branching ratio of the Z in the context of the light gluino scenario.
BOUND STATE AND RADIATIVE CORRECTIONS TO HEAVY QUARK FRAGMENTATION FUNCTIONS
Authors: NOBARY M.A. GOMSHI
Published: November 2004

We comment on heavy quark fragmentation models motivated by QCD and study the influence of bound state and radiative corrections on heavy quark fragmentation emphasizing the comparison between the theoretical predictions and experimental data. It seems that meson constituents internal motion and initial state QCD gluon radiation may have a kinematical role in improving the agreement between theory and experiment. These effects are more striking in the case of charm fragmentation.
BATALIN-TYUTIN QUANTIZATION OF THE CHERN-SIMONS-PROCA THEORY
Authors: PARK EI-BYUNG , KIM YONG-WAN , PARK YOUNG-JAI , KIM YONDUK , KIM WON TAE
Published: November 2004

We quantize the Chern-Simons-Proca theory in three dimensions by using the Batalin-Tyutin Hamiltonian method, which systematically embeds second-class constraint system into first-class by introducing new fields in the extended phase space. As a result, we obtain simultaneously the Stückelberg scalar term, which is needed to cancel the gauge anomaly due to the mass term, and the new type of Wess-Zumino action, which is irrelevant to the gauge symmetry. We also investigate the ir property of the Chern-Simons-Proca theory by using the Batalin-Tyutin formalism as compared to the symplectic formalism. As a result, we observe that the resulting theory is precisely the gauge-invariant Chern-Simons-Proca quantum-mechanical version of this theory.
GEOMETRICAL DESCRIPTION OF THE LOCAL INTEGRALS OF MOTION OF MAXWELL-BLOCH EQUATION
Authors: ANTONOV A.V. , FEIGIN B.L. , BELOV A.A.
Published: November 2004

We represent a classical Maxwell-Bloch equation and relate it to positive part of the AKNS hierarchy in geometrical terms. The Maxwell-Bloch evolution is given by an infinitesimal action of a nilpotent subalgebra n+ of affine Lie algebra [Formula: see text] on a Maxwell–Bloch phase space treated as a homogeneous space of n+. A space of local integrals of motion is described using cohomology methods. We show that Hamiltonian flows associated with the Maxwell–Bloch local integrals of motion (i.e. positive AKNS flows) are identified with an infinitesimal action of an Abelian subalgebra of the nilpotent subalgebra n− on a Maxwell–Bloch phase space. Possibilities of quantization and lattice setting of Maxwell–Bloch equation are discussed.
TACHYON EFFECTS ON THE TWO-DIMENSIONAL BLACK HOLE GEOMETRY
Authors: DIAMANDIS G.A. , GEORGALAS B.C. , PAPANTONOPOULOS E.
Published: November 2004

We study solutions of the tree level string effective action in the presence of the tachyon mode. In the case of static fields we find numerically that the full system has a black hole solution with the tachyon regular at the horizon. We also find a nonstatic exact solution of the equations of motion having a black hole structure with a past singularity.
POSSIBLE EXPLANATION FOR THE RATIO K/π IN pp COLLISIONS
Authors: YANG C.B. , YIN Z.B. , CAI X. , ZHOU Z.M.
Published: November 2004

The ratio K/π in pp collisions is investigated based on the constraints of the isospin conservation and the strangeness suppression. Numerical results on the ratios of K+/π+ and K−/π− are given for the relationship between the ratio and the multiplicity of produced particles.
RELATIVISTIC PARTICLE WITH TORSION AND CHARGED PARTICLE IN A CONSTANT ELECTROMAGNETIC FIELD: IDENTITY OF EVOLUTION
Authors: PLYUSHCHAY MIKHAIL S.
Published: November 2004

The identity of classical motion is established for two physically different models, one of which is the relativistic particle with torsion, whose action contains higher derivatives and which is the effective system for the statistically charged particle interacting with the Chern-Simons U(1) gauge field, and the other is the (2+1)-dimensional relativistic charged particle in external constant electromagnetic field.
EFFECTS OF G-PARITY AND u, d FLAVOR COHERENCE IN THE PARTIAL WIDTH FOR Z0 DECAY TO b-HADRONS
Authors: BARSHAY SAUL , HEILIGER PATRICK
Published: November 2004

In physical hadronic states arising from Z0 decay into [Formula: see text] in particular, those involving pairs of b-hadrons plus pions, constraints arise as a consequence of G-parity conservation, which involves u, d flavor coherence at a virtual gluon vertex. A result of these constraints is that, in general, the partial width contains a small term proportional to [Formula: see text] in addition to the usual, dominant term proportional to [Formula: see text] from the quark model. Our main point is that this nonperturbative effect can reach the level of a 0.3% correction to the standard number for (Γb/Γh) if there are residual of strong interaction phases in some states of the [Formula: see text] systems with magnitude of order of [Formula: see text][Formula: see text] where k is the relative momentum and R is a characteristic size of the interacting system.
PICARD-FUCHS EQUATIONS FOR THE K3 LANDAU-GINZBURG MODELS WITH c=6
Authors: RYANG SHIJONG
Published: November 2004

In the Landau-Ginzburg models we present the c=6 K3 superpotentials for the S14, U14, W15, Z15, K16 and Q14 types with one modality specified by Arnold and the [Formula: see text], [Formula: see text], [Formula: see text] ones with modified perturbation operators and so on. The Picard-Fuchs equation for each potential, of the Fermat type or not, is constructed and solved. We demonstrate the invariance of the Picard-Fuchs equation under the fractional field transformation.
UPPER BOUND ON THE MASS OF LIGHTEST HIGGS BOSON IN THE SUPERSYMMETRIC SINGLET MAJORAN MODEL
Authors: PANDITA P.N.
Published: November 2004

We calculate an upper bound on the lightest Higgs boson mass in the supersymmetric singlet majoran model containing SU(2)×U(1) singlet right-handed neutrino fields and a chiral singlet having two units of lepton number. We show that although the singlet vacuum expectation values and supersymmetry breaking masses do not decouple from the upper bound, even at the tree level, their effect is small, thereby reducing the bound to the corresponding bound in the minimal supersymmetric standard model. Radiative corrections to the bound are similar to those in the minimal model. We also show that the couplings of the lightest Higgs boson to the majorans are suppressed in this model.
G-ALGEBRA AND CURVED SPACETIME
Authors: SCIPIONI R.
Published: November 2004

The recently proved nonexistence of generalized statistics in curved spacetime is reconsidered in the framework of g-algebra; we show in a rigorous way that for asymptotic states, a Fermi or Bose statistics in the “in” region always evolves a Bose or Fermi statistics in the “out” region; the new approach, however, permits one to infer that this fact might not be true when considering intermediate states.
ON PHASE DIAGRAM OF GROSS-NEVEU MODEL AT FINITE TEMPERATURE, DENSITY AND CONSTANT CURVATURE
Authors: KANEMURA SHINYA , SATO HARU-TADA
Published: November 2004

We discuss a phase structure of chiral symmetry breaking in the Gross-Neveu model at finite temperature, density and constant curvature. The effective potential is evaluated in the leading order of the 1/N-expansion and in a weak curvature approximation. The third-order critical line is found on the critical surface in the parameter space of temperature, chemical potential and constant curvature.
EXTREMAL BLACK HOLES AND ELEMENTARY STRING STATES
Authors: SEN ASHOKE
Published: November 2004

Some of the extremal black hole solutions in string theory have the same quantum numbers as the Bogomol’nyi saturated elementary string states. We explore the possibility that these black holes can be identified with elementary string excitations. It is shown that stringy effects could correct the Bekenstein-Hawking formula for the black hole entropy in such a way that it correctly reproduces the logarithm of the density of elementary string states. In particular, this entropy has the correct dependence on three independent parameters, the mass and the left-handed charge of the black hole, and the string coupling constant.
ON THE STUDY OF J/Ψ SUPPRESSION IN THE QUARK GLUON PLASMA
Authors: CHAKRABARTI B. , REMADEVI T.L.
Published: November 2004

The time dependence of the suppression probability of the ground state meson in the Ψ-family due to the screening of plasma, when embedded in the medium of quark gluon plasma (QGP) is studied; the effect of the screening represented by the Hultheń potential on its suppression is however found to be not very pronounced as compared to the other theoretical works.
ANALYSIS OF REFRACTION EFFECTS IN NUCLEAR SCATTERING ON THE BASIS OF THE S-MATRIX APPROACH
Authors: BEREZHNOY YU. A. , PILIPENKO V.V.
Published: November 2004

A new S-matrix model is proposed to describe refraction effects in the intermediate energy light nucleus elastic scattering on atomic nuclei. An analysis of experimental data on scattering of 4 He , 6 Li and 16 O nuclei by different target nuclei is made on the basis of this model and the near-far decomposition of the scattering amplitude. Comparison of our results with those obtained by the optical model is discussed.
N = 2 SUPER-$W_3^{(2)}$ ALGEBRA IN SUPERFIELDS
Authors: IVANOV E. , KRIVONOS S. , SORIN A.
Published: November 2004

We present a manifestly N=2 supersymmetric formulation of N=2 super-[Formula: see text] algebra (its classical version) in terms of the spin-one unconstrained supercurrent generating an N=2 superconformal subalgebra and the spins-1/2, two bosonic and spins-1/2, two fermionic constrained supercurrents. We consider a superfield reduction of N=2 super-[Formula: see text] to N=2 super-W3 and construct a family of evolution equations for which N=2 super-[Formula: see text] provides the second Hamiltonian structure.
FINITE PARTICLE CREATION IN 3+1 DE SITTER SPACE
Authors: LAMB D.J. , CAPRI A.Z. , KOBAYASHI M.
Published: November 2004

In this paper we calculate the particle creation as seen by a stationary observer in 3+1 de Sitter space. This particle creation is calculated using an observer-dependent geometrically based definition of time which is used to quantize a field on two different spacelike surfaces. The Bogoliubov transformation relating these two quantizations is then calculated and the resulting particle creation is shown to be finite.
NUCLEAR ANAPOLE MOMENT IN RELATIVISTIC MODEL AND ITS EFFECT IN ATOMIC PARITY VIOLATION MEASUREMENTS
Authors: KULKARNI SWATI , WARKE C.S. , GAMBHIR Y.K.
Published: November 2004

An expression for nuclear anapole moment is derived within a valence nucleon relativistic mean-field nuclear model. The anapole moment parameter values are calculated for 133Cs, 85Rb, and 209Bi nuclei. The result reproduces the observed difference between hyperfine E1 transition amplitudes in 133Cs within the experimental accuracy. The change in the optical polarization rotation angle, induced by the parity violating electron-anapole interaction, in Bi is also calculated.
W∞ AND SLq(2) ALGEBRAS IN THE LANDAU PROBLEM AND CHERN-SIMONS THEORY ON A TORUS
Authors: HO CHOON-LIN
Published: November 2004

We discuss ω∞ and sl q(2) symmetries in Chern-Simons theory and Landau problem on a torus. It is shown that when the coefficient of the Chern-Simons term, or when the total flux passing through the torus is a rational number, there exist in general two w∞ and sl q(2) algebras, instead of one set each discussed in the literature. The general wave functions for the Landau problem with rational total flux is also presented.
STAR-MATRIX MODELS
Authors: VINTELER E.
Published: November 2004

The star-matrix models are difficult to solve due to the multiple powers of the Vandermonde determinants in the partition function. We apply to these models a modified Q-matrix aprpoach and we get results consistent with those obtained by other methods. As examples we study the inhomogeneous Gaussian model on Bethe tree and matrix q-Potts-like model. For the last model in the special cases q=2 and q=3, we write down explicit formulas which determine the critical behavior of the system. For q=2 we argue that the critical behavior is indeed that of the Ising model on the ϕ3 lattice.
QUANTUM LIOUVILLE THEORY FROM A DIFFEOMORPHISM CHERN-SIMONS ACTION
Authors: ASHWORTH M.C.
Published: November 2004

A Chern-Simons action written with Christoffel symbols has a natural gauge symmetry of diffeomorphisms. This Chern-Simons action will induce a Wess-Zumino-Witten model on the boundary of the manifold. If we restrict the diffeomorphisms to chiral diffeomorphism, the Wess-Zumino-Witten model is equivalent to a quantum Liouville action.
ELECTROMAGNETIC MODES AND ZERO-POINT ENERGY IN A DIELECTRIC ANNULAR REGION
Authors: BREVIK I.
Published: November 2004

The fundamental electric and magnetic modes are determined for an electromagnetic field contained in a spherical annular region a<r<b, filled with a medium of constant permittivity and permeability. The surfaces r=a and r=b are perfectly conducting. Knowledge about the mode spectrum enables one to calculate the zero-point energy in a very simple way, by means of a contour integration method.
A CONNECTION BETWEEN LATTICE AND SURGERY CONSTRUCTIONS OF THREE-DIMENSIONAL TOPOLOGICAL FIELD THEORIES
Authors: ASANO MASAKO , HIGUCHI SABURO
Published: November 2004

We study the relation between lattice construction and surgery construction of three-dimensional topological field theories. We show that a class of the Chung-Fukuma-Shapere theory on the lattice has representation theoretic reformulation which is closely related to the Altschuler-Coste theory constructed by surgery. There is a similar relation between the Turaev-Viro theory and the Reshetikhin-Turaev theory.
ON THE ZAMOLODCHIKOV AND FATEEV TRANSFORMATION
Authors: CHAKIR H. , FALLAH A. EL , SAIDI E.H.
Published: November 2004

The Zamolodchikov and Fateev transformation used in the elaboration of ZN×ZN parafermionic models is re-examined. It is shown that this transformation is in fact a projection of general Z2N×ZN models down to the standard ZN×ZN ones.
THE p, q-OSCILLATORS REPRESENTATION OF QUANTUM ALGEBRA SU(3)pq
Authors: DUNG LE VIET , LOAN NGUYEN THI HA
Published: November 2004

The representation, à la Schwinger, of quantum algebra SU(3)pq is considered by constructing quantum commutation relations for p, q-deformed harmonic oscillators. The obtained results can be seen as a two-parameter extension of the quantum algebra SU(3)q studied in Ref. 1.
EXTRAPOLATION OF POWER SERIES BY SELF-SIMILAR FACTOR AND ROOT APPROXIMANTS
Authors: YUKALOV V. I. , GLUZMAN S.
Published: November 2004

The problem of extrapolating the series in powers of small variables to the region of large variables is addressed. Such a problem is typical of quantum theory and statistical physics. A method of extrapolation is developed based on self-similar factor and root approximants, suggested earlier by the authors. It is shown that these approximants and their combinations can effectively extrapolate power series to the region of large variables, even up to infinity. Several examples from quantum and statistical mechanics are analyzed, illustrating the approach.
WAVE FRONT PROPAGATION AND ITS FAILURE IN COUPLED SYSTEMS OF DISCRETE BISTABLE CELLS MODELLED BY FITZHUGH-NAGUMO DYNAMICS
Authors: ANDERSON A.R.A. , SLEEMAN B.D.
Published: November 2004

We discuss wave front propagation and its failure for the discrete FitzHugh-Nagumo system. We show, using a new comparison theorem, that wave front propagation is blocked for d, the coupling coefficient, sufficiently small and propagation must occur for d sufficiently large. Our numerical simulations confirm the analytical findings. We also give a numerical estimate for the speed of propagating waves as a function of d.
DETECTING THE SYMMETRY OF ATTRACTORS FOR SIX OSCILLATORS COUPLED IN A RING
Authors: KROON MICHEL , STEWART IAN
Published: November 2004

We study a dynamical system modelling six coupled identical oscillators, introduced by Collins and Stewart in connection with hexapod gaits. The system has dihedral group symmetry D6, and they suggest that symmetric chaos may be present at some parameter values. We confirm this by employing the method of “detectives” introduced by Barany, Dellnitz, and Golubitsky. The paper is mainly intended as a case study in the use of detectives to analyse the symmetries of attractors, employing a system with a rich and varied range of bifurcations—both changing the symmetry and changing the dynamics—with a reasonably large dimensional phase space (here 12 dimensions). We confirm that detectives provide a quick and effective method for finding parameter values at which symmetry changes or other bifurcations occur. However, because of ambiguities in interpretation in practical cases, they should be supplemented, when necessary, by other diagnostic techniques. Convergence plots for ergodic sums appear to be especially useful, in addition to standard techniques such as phase portraits and Poincaré sections.
BORDERED MATRICES AND SINGULARITIES OF LARGE NONLINEAR SYSTEMS
Authors: GOVAERTS W.
Published: November 2004

We develop a general numerical method for the study of bifurcation problems (turning points, simple bifurcations, pitchfork bifurcations and a host of other singularities) that occur in the solutions to boundary value problems that depend on parameters.

Consider time-evolution equations of the form [Formula: see text] where u∈Rn is the state vector, λ∈Rp is a vector of parameters and F is a sufficiently smooth function with values in Rn. If this system describes a time-dependent boundary value problem then n≫p and the Jacobian Fu typically has a special sparsity pattern (banded, block banded,…).

A bordered matrix is an (n+m, n+m) matrix M (n≫m) that consists of a main (n, n) block A in the upper left corner (typically A is Fu or closely related to it) and bordering rows and columns.

We consider methods for computing singularities of the steady state solutions F(u, λ)=0 in the general sense of Golubitsky & Schaeffer [1985]. In the case of the cusp catastrophe, Griewank & Reddien [1989] showed that Newton schemes can be set up to compute such singularities by solving only a small number of bordered linear systems in each Newton step. Their method extends similar, older methods for the simplest catastrophe, the turning point.

We show that it is possible to set up a general scheme to compute any singularity with a small number of solutions of bordered systems in each Newton step; this number depends on the type of singularity but not on n.
BORDER-COLLISION CRISES IN A TWO-DIMENSIONAL MAP
Authors: Alvarez-Ramírez José
Published: November 2004

We examine crisis phenomena for a map that is piecewise linear and depend continuously of a parameter λ0. There are two straight lines Γ+ and Γ− along which the map is continuous but has two one-sided derivatives. As the parameter λ0 is varied, a periodic orbit Ƶp may collide with the borders Γ+ and Γ− to disappear. While in most reported crisis structures, a chaotic attractor is destroyed by the presence of (homoclinic or heteroclinic) tangencies between unstable periodic orbits, in this case the chaotic attractor is destroyed by the birth of an attracting periodic orbit Ƶp into that of attraction of the chaotic set. The birth of Ƶp is due to a border-collision phenomenon taking place at Γ+ ∪Γ−.
PERMANENT TRANSIENT CHAOS IN A TWO-DIMENSIONAL NON-INVERTIBLE MAP
Authors: STRUCHKOV I.N.
Published: November 2004

We study unusual chaotic transients towards the zero fixed point in the DAOD-map derived from differential equations of the delayed aperiodic oscillator [Rozhdestvensky et al., 1992; Struchkov, 1993], which is one of the simplest models of the radiophysical autogenerator with chaotic transients [Rozhdestvensky et al., 1992]. Unusual character of the observed chaotic transients manifests itself in near-linear increase of the Ln[τ(p)]-curve for its average lifetime τ(p) as a function of system’s parameter p. Parameter p is corresponding to the amplifying coefficient of the radio-physical autogenerator [Rozhdestvensky et al., 1992]. This curve includes lacunas when p belongs to the periodic windows (when p∈∆n). In small enough neighborhood of ∆nLn[τ(p)]-curve behaves itself like as in boundary crisis due to intermittency. Permanent presence of the transient chaos in the DAOD-map (even when p∈∆n) is caused by the existence in phase space of the Monotonous Descent Channel (MDCh), which is coming in a zero fixed point from infinity.
ITERATION OF QUATERNION MAPS
Authors: BEDDING STEPHEN , BRIGGS KEITH
Published: November 2004

Quaternions are an extension of the idea of complex numbers to four dimensions. We discuss the iteration of linear and quadratic functions of the quaternions, and examine the rôle played by regularity (the analog of complex analyticity), in this context. In contrast to the complex case, regularity is not automatically preserved by iteration of quaternion functions. We find that demanding preservation of regularity is too restrictive, yielding very little new beyond the complex case. The quaternion generalisation of the Mandelbrot set is described.
THE RESPONSE OF A NONLINEAR SYSTEM WITH A NONSEMISIMPLE ONE-TO-ONE RESONANCE TO A COMBINATION PARAMETRIC RESONANCE
Authors: CHIN C. , NAYFEH A. H. , MOOK D. T.
Published: November 2004

The Galerkin procedure is used to discretize the nonlinear partial differential equation and boundary conditions governing the flutter of a simply supported panel in a supersonic stream. These equations have repeated natural frequencies at the onset of flutter. The method of multiple scales is used to derive five first-order nonlinear ordinary-differential equations governing the modulation of the amplitudes and phases of the excited modes. Then, the modulation equations are used to calculate the equilibrium solutions and their stability, and hence to identify the excitation parameters that suppress flutter and those that lead to complex motions. A combination of a shooting technique and Floquet theory is used to calculate limit cycles and their stability. The numerical results indicate the existence of a sequence of period-doubling bifurcations that culminates in chaos. The complex motions are characterized by using phase planes, power spectra, Lyapunov exponents, and dimensions.
ANALYSIS OF THE CONTROL OF CHAOS-RATE OF CONVERGENCE
Authors: ASTON P. J. , BIRD C. M.
Published: November 2004

In this paper we look at the convergence properties of a well-known method for controlling chaos recently devised by Ott, Grebogi and Yorke (OGY) ["Controlling chaos," Phys. Rev. Lett.64 (11), 1990, pp. 1196-1199]. From this analysis we arrive at a number of improved methods in that they possess better convergence properties than the OGY method. The control methods are similarly implemented via small bounded perturbations of a single system parameter, or the use of a second parameter and are shown to be superior to the OGY method in the control of the Duffings equation.
SUNSPOT ACTIVITY CURVES AND INTERMITTENT CHAOTIC BEHAVIOR
Authors: GÜRBÜZ GÜLŞEN , BECK CHRISTIAN
Published: November 2004

We analyze the statistical properties of observed sunspot numbers. Near the Maunder minimum, the dynamics of successive sunspot maxima is low-dimensional and has properties similar to the intermittent logistic map. The long-term statistics is well described by an intermittent random injection model with Poissonian injection statistics. Three different characteristic numbers are extracted from the solar signal: The distance from the critical point of tangent bifurcation, the injection probability into the laminar phase, and the relaxation time of correlations. It is suggested to interpret the grand minima of the solar cycle as the laminar phase of the intermittent solar dynamo.
COEXISTENCE OF CYCLES OF A CONTINUOUS MAP OF THE LINE INTO ITSELF
Authors: SHARKOVSKIĬ A. N.
Published: November 2004

The basic result of this investigation may be formulated as follows. Consider the set of natural numbers in which the following relationship is introduced: n1 precedes n2 (n1 ≼ n2) if for any continuous mapping of the real line into itself the existence of a cycle of order n2 follows from the existence of a cycle of order n1. The following theorem holds.
TOWARD A THEORY OF FORCING ON MAPS OF TREES
Authors: BALDWIN STEWART
Published: November 2004

The "forcing" relation on patterns of invariant subsets of maps on the interval has proved to be a useful tool for studying the dynamics of interval maps. However, attempts to generalize this relation to more general spaces (such as trees) have met with difficulties. A new relation is introduced, which is well-defined for all continuous maps on any dendrite, is closely related to the forcing relation on the unit interval, and has at least some of the nice properties on trees which one would expect from a generalized forcing relation.
SMOOTH TRIANGULAR MAPS OF TYPE 2∞ WITH POSITIVE TOPOLOGICAL ENTROPY
Authors: BALIBREA FRANCISCO , ESQUEMBRE FRANCISCO , LINERO ANTONIO
Published: November 2004

We explicitly construct for any k in ℕ a [Formula: see text]-differentiable triangular map in the square I2 with the following properties: (a) it has periodic orbits of period 2n for any n and no other periodic orbits, (b) the topological entropy is positive, and (c) the set of recurrent points contains properly the set of uniformly recurrent points.
PERIODS FOR MAPS OF THE FIGURE-EIGHT SPACE
Authors: GILLOT CHRISTIAN , LLIBRE JAUME
Published: November 2004

Let Per (f) denote the set of periods of all periodic points of a map f from a topological space into itself. Let 8 be the figure-eight space. We extend to the 8 the following theorem from the circle due to Block [1981]. Let [Formula: see text] be the circle. For every map [Formula: see text] with Per (f) ∩ {1, 2, …, n} = {1, n} and n > 2 we have Per (f) = {1, n, n+1, n+2, …}. Conversely, for every n ∈ ℕ with n > 2 there exists a map [Formula: see text] such that Per (f) = {1, n, n+1, n+2, …}.

For the space 8 we prove the following. Let f: 8 → 8 be a continuous map having the branching point fixed and such that Per (f) ∩ {1, 2, …, n} = {1, n} with n > 4. Then Per (f) is either {1, n, n+1, n+2, …}, or {1, n, n+2, n+4, …} with n even, or {1, n, n+2, n+4, …}∪ {2n+2, 2n+4, 2n+6, …} with n odd. Conversely, for every n ∈ ℕ with n > 4, if A (n) is one of the above three subsets of ℕ, then there is a continuous map f: 8 → 8 having the branching point fixed and such that Per (f) = A (n).
ORDER AND CHAOS FOR A CLASS OF PIECEWISE LINEAR MAPS
Authors: LÓPEZ VÍCTOR JIMÉNEZ
Published: November 2004

For a class of piecewise linear maps f: I → I from a compact interval I into itself, we describe the asymptotic behavior of the sequence [Formula: see text] for almost all x ∈ I. We also study in this setting the relations among sensitive dependence on initial conditions, existence of scrambled sets of positive measure and existence of absolutely continuous invariant measures.
"CONNECT-THE-DOTS" TREE MAPS
Authors: ALSEDÀ LLUÍS , GUASCHI JOHN , LOS JÉRÔME , MAÑOSAS FRANCESC , MUMBRÚ PERE
Published: November 2004

We announce the main results of work in progress on piecewise monotone models for patterns of tree maps. More precisely, we define a notion of pattern for tree maps, and given such a pattern, we construct a tree and a piecewise monotone map on this tree with the same pattern. This piecewise monotone model has the least entropy among all models exhibiting the given pattern and has "minimal dynamics". We also give a formula to compute this minimal entropy directly from the pattern. These results generalize the known results for interval maps and the results from Li & Ye [1993].
COMPUTING THE DISTRIBUTION OF THE LYAPUNOV EXPONENT FROM TIME SERIES: THE ONE-DIMENSIONAL CASE STUDY
Authors: LAI DEJIAN , CHEN GUANRONG
Published: November 2004

In this paper, a simple and direct statistical method is proposed for estimating the Lyapunov exponent of an unknown dynamic system using its time series of observation data. It is shown that the asymptotic distribution of the estimates obtained from the proposed method is normal. Monte Carlo and block bootstrap methods are used to simulate the estimation for the logistic map, in which they both provide the expectation and variance for the estimates. Computer simulations show that our estimates are very close to the true values of the exponent for the logistic map with different parameters.
FRACTAL GEOMETRY OF RESTRICTED SETS OF CIRCLE INVERSIONS
Authors: CLANCY COLLEEN , FRAME MICHAEL
Published: November 2004

For intersecting circles, we propose a modification of the limit set generated by inversion in circles. This restricted limit set is always a subset of the discs bounded by the generating circles. We give examples of restricted limit sets and show arrangements of generating circles for which the restricted limit set equals the limit set, and also arrangements for which they differ. In addition, we give a visual presentation, based on Iterated Function Systems, of the excluded strings in the restricted limit set. This leads to a graphical representation of the grammatical complexity of the restricted limit set.
QUADTREES, MANDELBROT PERCOLATION AND THE MODELLING OF RANDOM SETS
Authors: DEKKING F.M.
Published: November 2004

Any binary image can be represented by a quadtree. Therefore random quadtrees correspond to bounded random sets in the plane. We discuss various possibilities for randomizing the quadtree. The most natural randomization yields Mandelbrot percolation.
KNUDSEN DIFFUSION IN POROUS CATALYSTS WITH A FRACTAL INTERNAL SURFACE
Authors: COPPENS MARC-OLIVIER , FROMENT GILBERT F.
Published: November 2004

Porous amorphous catalysts often have a fractal internal surface down to molecular scales. The movement of gas molecules inside the narrow channels that constitute all or most of the pore space, is mainly hindered by collisions with the surface, rather than with each other: Knudsen diffusion, rather than bulk molecular diffusion is then the main diffusion mechanism. The influence of the fractal surface morphology on the Knudsen diffusivity is investigated. A momentum transfer technique leads to a smooth field approximation for the Knudsen diffusivity. The dependence of the surface accessibility on the size of the molecules causes the Knudsen diffusivity of a molecule to depend on its effective diameter. Because the previous method assumes a uniform surface accessibility, a first-passage time technique is developed, which accounts for the true accessibility distribution over the surface. The problem is solved analytically and the result is a simple expression of the Knudsen diffusivity. Extensions of this technique to other problems in catalysis and to other fields are discussed. Once a property, like the Knudsen diffusivity, is known for a medium with smooth walls, the method developed here allows us to calculate the same property for a medium with fractal walls.
FINITE DIFFERENCE TREATMENT OF IRREGULAR INTERFACES: AN ERROR ANALYSIS
Authors: LEE DING , SIEGMANN WILLIAM L.
Published: November 2004

The application of finite difference schemes to handle a horizontal interface between two media gives numerically adequate results, as evidenced in the solution of parabolic wave equations with density variations. Using the same finite difference schemes for handling a stair-step approximation to an irregular interface gives satisfactory results provided that the slope angle is small, but a small error is introduced. In the event that the slope angle is not small, this error has to be handled carefully since it may influence the results. Using an analysis of the error, this paper derives a closed form expression for a correction term. An irregular interface can then be handled adequately by the same numerical treatment used for the horizontal interface by applying this correction term. A test case is presented to demonstrate the inaccuracy of using one standard numerical horizontal interface treatment and to show how our new development improves the accuracy.
TEMPORAL CHARACTERISTICS OF ACOUSTIC RAY PROPAGATION THROUGH "INFINITE" AND "BOX MODEL" TURBULENCE
Authors: KARWEIT MICHAEL , BLANC-BENON PHILIPPE
Published: November 2004

In this work, we investigate the temporal characteristics of acoustic ray propagation through simulated, weakly turbulent temperature fields. In a first set of experiments, we generate ensembles of random scalar fields from randomly oriented Fourier temperature modes. Then, by integrating the ray trace equations, we estimate the distribution of arrival times for rays propagating a distance R through them. We demonstrate that these arrival time distributions are Gaussian for both axial and 3-D propagation and are primarily determined by the lower wave numbers of the 1-D fluctuation spectrum.

In a second set of experiments, we generate random fields comprised of Fourier modes prescribed on a lattice, as in "box model" turbulence. In these simulations, we find that acoustic travel times are significantly affected both by the periodicity of the fields and by the direction of acoustic propagation with respect to the orientation of the box. Both effects can ultimately be attributable to an inadequate representation of the low wave number region of the 1-D spectrum. We suggest that these artifacts of simulated periodic fields may preclude their use for acoustic propagation studies.
CHARACTERIZATION OF A VERTICAL SURFACE-BREAKING CRACK IN PLATES
Authors: LAM K. Y. , LIU G. R. , Wang Y. Y.
Published: November 2004

A new technique in the frequency domain is presented for the characterization of a surface-breaking crack in plates. The strip element method has been used to calculate the responses of the displacement field in the plate subjected to a time harmonic line load on the upper surface of the plate. In the present technique, the crack can be located from the distribution of the displacement field, which is found to be discontinuous at the crack position. It is found that there are additional oscillations in the curve of the absolute values of the displacement in between the load and the crack. The crack length can be determined from the mean value of the peak of the additional oscillations. It is also found that the mean value of the peak is dependent on the crack length and less dependent on the distance from the load to the crack. Approximate polynomial formula of degree three for predicting the length of surface-breaking crack in isotropic homogeneous plates is also proposed. Numerical examples are given to demonstrate the present technique.
INTERACTIONS AT METAL/OXIDE AND OXIDE/OXIDE INTERFACES STUDIED BY ULTRATHIN FILM GROWTH ON SINGLE-CRYSTAL OXIDE SUBSTRATES
Authors: LAD ROBERT J.
Published: November 2004

This article reviews aspects of the electronic, chemical, and structural properties of metal/oxide and oxide/oxide interfaces which are formed via ultrathin film growth on oxide single-crystal surfaces. The interactions at the interfaces are classified based on the nature of the reaction products, thermodynamic predictions of interfacial reactions, and wetting and adhesion. Then, properties of single-crystal oxide substrates and limitations and difficulties in studying these ceramic systems are discussed. The remainder of the article presents experimental observations for several systems involving both metal and oxide ultrathin film growth on stoichiometric NiO (100), TiO 2(110), and [Formula: see text] surfaces including a discussion of interdiffusion, chemical and electronic interactions, thermal stability, and interfacial impurity effects.
CHEMICAL RECONSTRUCTION OF THE TiAl(010) SURFACE
Authors: WANG C.P. , KIM S.K. , JONA F. , STRONGIN D.R. , SHEU B.-R. , MARCUS P.M.
Published: November 2004

The atomic structure of a clean (010) surface of the ordered binary alloy TiAl (with tetragonal bulk structure of the CuAu I type) is studied with quantitative low-energy electron diffraction (QLEED). Two different surface phases are found depending on the preparation procedure. After a cleaning step in vacuo by means of Ar-ion bombardments, anneals at 750−850°C produce a 2×1 surface and anneals at about 900° C produce a 1×1 surface. A QLEED intensity analysis of the 1×1 structure reveals the occurrence of chemical reconstruction, whereby the Ti atoms in the first layer exchange places with the Al atoms in the second layer. Thus, while any bulk (010) plane contains 50% Al and 50% Ti , the top atomic layer of a (010) surface contains 100% Al and the second atomic layer contains 100% Ti . Both layers are slightly buckled and the first interlayer distance is compressed about 7.1% while the second interlayer spacing is expanded about 7.4% with respect to the bulk value.
INFLUENCE OF A TIP/SAMPLE INTERACTION ON SCANNING TUNNELING SPECTROSCOPY DATA
Authors: ZAVODINSKY V.G. , KUYANOV I.A.
Published: November 2004

The electronic states and the tunnel current for the W/Si and W/Al tip/sample systems were calculated by the first-principles discrete-variational method of the local-density approximation. It was found that the local-electronic structure of the Si surface resembles that of a free sample even for the tip/sample distances of 2–3 Å. The electronic structure of the Al surface is more sensitive to the tip/sample interaction and approaches the free surface form when the tip/sample distance is larger than 4 Å. The local density of states of the W tip also depends on the tip/sample distance and must be taken into account in the tunnel-current calculations and in the interpretations of the STS data.
ANOMALOUS SURFACE CORE-LEVEL SHIFTS ON Be METAL
Authors: JOHANSSON L.I.
Published: November 2004

An unusual behavior of the surface core-level shifts on the three low-index surfaces of Be metal has been revealed. Three surface-shifted Be 1s components were identified in photoemission studies of both the (0001) and the [Formula: see text] surfaces while for the [Formula: see text] surface only one surface-shifted component was resolved. On the close-packed (0001) surface, components shifted by –825, –570, and –265 meV relative to the bulk component were revealed and interpreted to originate from the three outermost surface layers. For the [Formula: see text] surface, components shifted by –700, –500, and –220 meV were determined and interpreted to originate from the first, second, and third plus fourth atomic layers. For the [Formula: see text] surface only one component shifted by –410 meV was resolved and interpreted to originate from atoms in the outermost layer. These findings are most unusual since two subsurface core-level shifts have previously not been observed on a close-packed metal surface, and larger surface shifts are determined for the close-packed (0001) surface compared to the more open [Formula: see text] and [Formula: see text] surfaces. This latter is contrary to all previous findings on other metal surfaces and also contrary to the predictions of the partial-shift model, which previously has been successfully applied to several metallic systems. The experimental findings are reviewed and reasons for this unusual behavior of the surface shifts are discussed in view of recent theoretical results.