bluuebunny/crossref_metadata_2025 huggingface dataset:
ABSENCE OF 1/f SPECTRA IN DOW JONES DAILY AVERAGE
Authors: LI WENTIAN
Published: November 2004

The power spectrum of the daily Dow Jones industrial average is calculated. It has been shown that the spectrum is P(f) ~1/f1.8, very close to that of the random walk series (1/f2 noise). In contrast to some previous belief, the Dow Jones index as well as other stock prices time series are not 1/f noise. The distribution of the daily change of the Dow Jones industrial average is also calculated. Several fittings of the distribution are carried out (for both the price change and the logarithm of the price change). It has been observed that the occurrence of the big loss on Black Monday (negative change of 508) does not fit the distribution of the smaller price fluctuations (e.g., smaller than 100). This lack of scaling for the frequency of occurrence from the large stock price losses to small price fluctuations can be compared with the much better scaling law in the frequency of occurrence for global earthquakes.
CALCULATING STABLE AND UNSTABLE MANIFOLDS
Authors: YOU ZHIPING , KOSTELICH ERIC J. , YORKE JAMES A.
Published: November 2004

A numerical procedure is described for computing the successive images of a curve under a diffeomorphism of RN. Given a tolerance ε, we show how to rigorously guarantee that each point on the computed curve lies no further than a distance ε from the "true" image curve. In particular, if ε is the distance between adjacent points (pixels) on a computer screen, then a plot of the computed curve coincides with the true curve within the resolution of the display. A second procedure is described to minimize the amount of computation of parts of the curve that lie outside a region of interest. We apply the method to compute the one-dimensional stable and unstable manifolds of the Hénon and Ikeda maps, as well as a Poincaré map for the forced damped pendulum.
ON THE "CROSSROAD AREA–SADDLE AREA" AND "CROSSROAD AREA–SPRING AREA" TRANSITIONS
Authors: MIRA C. , CARCASSÈS J. P.
Published: November 2004

Let T be a one-dimensional or two-dimensional map. The three considered areas are related to three different configurations of fold and flip bifurcation curves, centred at a cusp point of a fold curve in the T parameter plane (b, c). The two transitions studied here occur via a codimension-three bifurcation defined in each case, when varying a third parameter a. The transition "mechanism," from an area type to another one, is given with a three-dimensional representation describing the sheet configuration of the parameter plane.
THE TAKENS EMBEDDING THEOREM
Authors: NOAKES LYLE
Published: November 2004

In his paper [Takens, 1981] on strange attractors and turbulence, Floris Takens proves a theorem giving conditions under which a discrete-time dynamical system can be reconstructed from scalar-valued partial measurements of internal states. We discuss Takens' theorem in terms suitable for a general audience, and give an alternative and more detailed proof of this important result, making use of two basic facts. The first is the Whitney embedding theorem, which we use in an alternative to Takens' original argument away from periodic points of small periods. Near the periodic points we adapt a proof that typical scalar-output linear time-invariant control systems are completely observable.
PERIODIC INHIBITION OF LIVING PACEMAKER NEURONS (II): INFLUENCES OF DRIVER RATES AND TRANSIENTS AND OF NONDRIVEN POSTSYNAPTIC RATES
Authors: SEGUNDO J. P. , ALTSHULER E. , STIBER M. , GARFINKEL A.
Published: November 2004

This paper discusses synaptic inhibition of one pacemaker neuron by another, using data from living synapses. Spike discharges were assimilated to point processes.

Inhibitory rate scale and behavior form. (i) Forms (p:q locked and others) with similar prevalent spectral components assembled monotonically with p:q. Between different lockings, intermittent, messy and other intermittent forms staggered characteristically; hoppings were interspersed. (ii) Locked, intermittent and messy forms occupied about 1/3 each of the rate scale. Individually, the 1:1, 2:1 and 1:2 locked domains were the widest, and seemed continuous; individual intermittent and messy domains were very narrow.

Step-like inhibitory transients induced abrupt postsynaptic changes opposing them, which over- or under-shot and slowly returned in either orderly or complicated (chaotic?) ways to steady states. Input-output relations around inhibitory trains resembled those of first-order lead-lag systems distorted by asymmetric sensitivity to change and saturation. Postsynaptic natural discharges separated into "slow" less variable, and "fast" more variable categories with somewhat different inhibited behaviors.

Formal modeling is introduced by summarizing comparable models, the data-assumption discrepancies, and reasonable conjectures as to eventual models.
A STABLE KNOTTED SINGULARITY IN AN EXCITABLE MEDIUM
Authors: HENZE CHRIS , WINFREE ART
Published: November 2004

Numerical studies of an apparently stable knotted singularity are used here to seek out regularities of vortex dynamics in three-dimensional excitable media. Initial conditions were contrived to produce a vortex filament in the form of a trefoil (3:2 torus) knot, using the piecewise linear 'B-kinetics', with excitability parameter 'g' set to 0.9. The simulation was pursued for 3000 time units, or about 125 wave rotations, during which time the knot was observed to rigidly 'precess' about its symmetry axis, completing one turn every 96 wave rotations, and also translate along that same axis, at about 1 percent of wavespeed. These motions, described with respect to the local Frenet frame, were shown to be highly correlated with local geometry and twist, yielding possible 'laws of filament motion', which might prove viable in other contexts. The trefoil knot is the first organizing center to be studied in detail which exhibits nonuniform twist, and its dynamical behavior supports the notion that the arclength derivative of twist is an important determinant of filament motion, first postulated by Keener in 1988. The knot also exhibited changes in twist distribution, and, to a lesser extent, local geometry, within one wave rotation period, adding an unforeseen complication to efforts at understanding vortex dynamics. The knot is compact, only about a wavelength in radius, so filament interactions may play a prominent role in determining the stability and behavior of the object. The locus of wave collisions was determined for the knot; in places this surface apparently adjoins the filament itself. In the course of this study, two different criteria for locating the filament were compared, and many analytic and graphical utilities were developed, which may prove useful in further studies of three-dimensional excitable media.
COEXISTING CHAOTIC ATTRACTORS IN CHUA'S CIRCUIT
Authors: LOZI RENÉ , USHIKI SHIGEHIRO
Published: November 2004

In this letter we report the numerical observation of the co-existence of three distinct chaotic attractors for at least one choice of parameters (α = 15.60, β = 28.58, m0 = −1/7, m1 = 2/7) in Chua's circuit. This new phenomenon may have escaped earlier detection because the three attractors are located very close to each other and requires the "zooming" ability of our confinor approach to uncover them.
VIEWPOINTS: A FRAMEWORK FOR INTEGRATING MULTIPLE PERSPECTIVES IN SYSTEM DEVELOPMENT
Authors: FINKELSTEIN A. , KRAMER J. , NUSEIBEH B. , FINKELSTEIN L. , GOEDICKE M.
Published: November 2004

This paper outlines a framework which supports the use of multiple perspectives in system development, and provides a means for developing and applying systems design methods. The framework uses "viewpoints" to partition the system specification, the development method and the formal representations used to express the system specifications. This VOSE (viewpoint-oriented systems engineering) framework can be used to support the design of heterogeneous and composite systems. We illustrate the use of the framework with a small example drawn from composite system development and give an account of prototype automated tools based on the framework.
RANDOMIZED PARALLEL ALGORITHMS FOR TRAPEZOIDAL DIAGRAMS
Authors: CLARKSON KENNETH L. , COLE RICHARD , TARJAN ROBERT E.
Published: November 2004

We describe randomized parallel algorithms for building trapezoidal diagrams of line segments in the plane. The algorithms are designed for a CRCW PRAM. For general segments, we give an algorithm requiring optimal O(A+n log n) expected work and optimal O( log n) time, where A is the number of intersecting pairs of segments. If the segments form a simple chain, we give an algorithm requiring optimal O(n) expected work and O( log n log log n log * n) expected time , and a simpler algorithm requiring O(n log * n) expected work. The serial algorithm corresponding to the latter is among the simplest known algorithms requiring O(n log * n) expected operations. For a set of segments forming K chains, we give an algorithm requiring O(A+n log * n+K log n) expected work and O( log n log log n log * n) expected time. The parallel time bounds require the assumption that enough processors are available, with processor allocations every log n steps.
PARABOLIC SUBGROUPS AND CUSPIDAL REPRESENTATIONS OF FINITE MONOIDS
Authors: OKNIŃSKI JAN , PUTCHA MOHAN S.
Published: November 2004

This paper is mostly concerned with arbitrary finite monoids M with the complex semigroup algebra [Formula: see text] semisimple. Using the 1942 work of Clifford, we develop for these monoids a theory of cuspidal representations. Harish-Chandra's philosophy of cuspidal representations of finite groups can then be derived with an appropriate specialization. For [Formula: see text], we use Solomon's Hecke algebra to obtain a correspondence between the 'simple' representations of [Formula: see text] and the representations of the symmetric inverse semigroup. We also prove a semisimplicity theorem for a special class of finite monoids of the type which was earlier used by the authors to prove the semisimplicity of [Formula: see text].
CONSTANT-DEPTH PERIODIC CIRCUITS
Authors: STRAUBING HOWARD
Published: November 2004

This paper is devoted to the languages accepted by constant-depth, polynomial-size families of circuits in which every circuit element computes the sum of its input bits modulo a fixed period q. It has been conjectured that such a circuit family cannot compute the AND function of n inputs. Here it is shown that such circuit families are equivalent in power to polynomial-length programs over finite solvable groups; in particular, the conjecture implies that Barrington's result on the computational power of branching programs over nonsolvable groups cannot be extended to solvable groups. It is also shown that polynomial-length programs over dihedral groups cannot compute the AND function. Furthermore, it is shown that the conjecture is equivalent to a characterization, in terms of finite semigroups and formal logic, of the regular languages accepted by such circuit families. There is, moreover, considerable independent evidence for this characterization. This last result is established using new theorems, of independent interest, concerning the algebraic structure of finite categories.
ON COMPLETE CONGRUENCE LATTICES OF COMPLETE MODULAR LATTICES
Authors: FREESE R. , GRÄTZE G. , SCHMIDT E. T.
Published: November 2004

The lattice of all complete congruence relations of a complete lattice is itself a complete lattice. In 1988, the second author announced the converse: every complete lattice L can be represented as the lattice of complete congruence relations of some complete lattice K. In this paper we improve this result by showing that K can be chosen to be a complete modular lattice.
HYPERBOLICITY OF GROUPS WITH SUBQUADRATIC ISOPERIMETRIC INEQUALITY
Authors: YU. OL'SHANSKII A.
Published: November 2004

The author gives a simple and coherent proof of Gromov's statement on hyperbolicity of groups with subquadratic isoperimetric inequality.
TERM REWRITE RULES FOR FINITE FIELDS
Authors: BURRIS STANLEY , LAWRENCE JOHN
Published: November 2004

Let F1, …, Fk be finite fields with distinct characteristics. We give a finite set of equations which axiomatize the equational theory of F1, …, Fk and then use these axioms to find a finite set of AC-term rewrite rules which is complete for this theory.

This gives finite sets of complete AC-term rewrite rules for most instances of xm ≈ x rings by adding new rules to the usual AC-term rewrite rules for commutative rings. The first case for which we do not find a complete set of AC-term rewrite rules is x22 ≈ x, and we doubt that such rules can be found. If R is a set of AC-term rewrite rules from which one can derive x(y + z) → xy + xz, then we show R cannot be complete for x22 ≈ x rings.
FINDING TYPE SETS IS NP-HARD
Authors: HOBBY DAVID
Published: November 2004

It is shown that determining the type set of the variety generated by a finite algebra is a P-Space-hard problem. This is done by interpreting into it the P-Space-complete problem of determining if a given function is a composition of a set of unary functions on a set. Specifically, the given function is a composition of the others just when the type 3 is not in the type set of the variety generated by the algebra that is constructed. A lemma that restricts the types that are possible in the variety generated by a given algebra is also given.
THE RULE OF LITTLEWOOD-RICHARDSON IN A CONSTRUCTION OF BERENSTEIN-ZELEVINSKY
Authors: CARRÉ C.
Published: November 2004

The rule of Littlewood-Richardson gives the decomposition of a product of Schur functions in the basis of the same functions. Each coefficient of this decomposition is the number of factorizations of a tableau of Yamanouchi in the plactic algebra. A. D. Berenstein and A. V. Zelevinksy prove that these coefficients are also the numbers of certain configurations called triangles. This text gives an explicit bijection between these triangles and the words of Yamanouchi.
COMPUTATION OF DIMENSION POLYNOMIALS
Authors: KONDRAT’EVA M.V. , LEVIN A.B. , MIKHALEV A.V. , PANKRAT’EV E.V.
Published: November 2004

The consideration of differential versions of Hilbert dimension polynomials is due to A. Einstein [1] and E. Kolchin [2] (one can find the coverage of the theory of differential dimension polynomials in [6]). In this paper we introduce the notion of a dimension polynomial of a subset of ℕm associated with arbitrary partition of the set {1,…, m} into disjoint nonempty subsets (m∈ℕ, ℕ denoting the set of all nonnegative integers). The theory of such polynomials is developed. The importance of our considerations is connected with the fact that the computation of differential and difference dimen sion polynomials may be reduced to the computation of some dimension polynomials of subsets of ℕm where m∈ℕ (see [3, p. 115], [5]). We also give some methods and algorithms for computation of dimension polynomials.
ON THE CONJUGACY PROBLEM FOR ONE-RELATOR MONOIDS WITH ELEMENTS OF FINITE ORDER
Authors: ZHANG LOUXIN
Published: November 2004

A one-relator monoid has nontrivial elements of finite order if and only if its presentation has the form (A; (PQ)mP=(PQ)nP), where PQ is a primitive word and m>n≥0. The (left-)conjugacy problem for such a monoid is shown to be reducible to the same problem for its left monoid. In particular, the (left-)conjugacy problem is decidable for the monoids M(A;(PQ)mP=(PQ)nP), where m+n≥2.
A CONDITION GUARANTEEING COMMUTATIVITY
Authors: HENTZEL IRVIN ROY , JACOBS D.P.
Published: November 2004

We give a simple characterization for a nonassociative algebra [Formula: see text], having characteristic ≠2, to be commutative. Namely, [Formula: see text] is commutative if and only if it is flexible with a commuting set of generators. A counterexample shows that characteristic ≠2 is necessary. Both the characterization and the counterexample were discovered using the computer algebra system in [2].
OPTICAL PROPERTIES OF CdTe AND CdS QUANTUM DOTS IN GLASS
Authors: ESCH V. , KANG K. , FLUEGEL B. , HU Y.Z. , KHITROVA G. , GIBBS H.M. , KOCH S.W. , PEYGAMBARIAN N. , LIU L.C. , RISBUD S.H.
Published: November 2004

We summarize the linear and nonlinear optical properties of a variety of CdTe and CdS quantum dots in glass. The measured linear absorption of the CdTe sample is compared with calculations involving valence-band mixing due to the quantum confinement. The temperature dependence of the lowest quantum-confined transition and its linewidth for samples with various crystallite sizes are measured and compared with a simple model. It is found that the shift of the energetically lowest quantum-confined transition as a function of temperature is the same as the temperature-dependent band-gap reduction in bulk materials. Excitation of the sample with pulses ranging from femtoseconds to microseconds allows distinguishing between various mechanisms responsible for the observed optical nonlinearities. At very early times, phase-space filling and Coulomb interaction between the excited charged carriers are responsible for the absorption changes. At later times, Coulomb effects due to “trapped” carriers remain and last for nanoseconds or microseconds.
PHOTOREFRACTIVE MEDIA FOR OPTICAL INTERCONNECTIONS
Authors: YEH POCHI , GU CLAIRE
Published: November 2004

The photorefractive effect and its applications in optical interconnections are described. The fundamental limit, the dynamics of grating formation, and the two-wave mixing (TWM) process are discussed. Reconfigurable interconnections for parallel optical computing is demonstrated using photorefractive holograms. Neural network interconnections with photorefractive media are also presented.
EXCITONIC BAND-EDGE ELECTRO-ABSORPTION IN MULTIPLE-QUANTUM-WELL WAVEGUIDE MODULATOR STRUCTURES
Authors: HUNT N.E.J. , JESSOP P.E.
Published: November 2004

Electric field induced changes in the excitonic band-edge absorption spectra of Multiple-Quantum-Well (MQW) structures were investigated theoretically and experimentally. A comparison was made of three different exactly solvable methods for calculating quantum-well energies. The small effects due to conduction-band nonparabolicity and valence-band mixing were included. Transmission spectra were recorded for an In .12 Ga .88 As-GaAs optical waveguide modulator structure. The theoretical model was used to predict the changes in the long-wavelength tail of the band-edge absorption for different electric fields.
TWO-PHOTON ABSORPTION IN POTASSIUM DIHYDROPHOSPHATE, POTASSIUM PENTABORATE AND QUARTZ CRYSTALS AT 270 AND 216 nm
Authors: GURZADYAN G.G. , ISPIRYAN R.K.
Published: November 2004

The absolute coefficients of two-photon absorption (TPA) of KDP, KB 5 O 8 · 4 H 2O, quartz and fused silica at 270 and 216 nm are measured. At 216 nm, TPA coefficients of these optical materials are approximately equal: β=(4÷6, 5) · 10−10 cm/W. The presence of crystal dopes is shown to increase nonlinear losses beginning from the intensities ~107 W/cm2.
SELF-FOCUSING EFFECTS AND APPLICATIONS USING THIN NONLINEAR MEDIA
Authors: HERMANN J.A.
Published: November 2004

A model of the nonlinear optical effects attending the interaction of a laser beam with a thin Kerr-type medium has been analyzed in detail. The formalism developed is applicable to both near- and far-field situations. Some possible applications are discussed.
FREQUENCY DETUNING IN BRILLOUIN INDUCED FOUR-WAVE MIXING
Authors: RIDLEY K.D. , SCOTT A.M. , JONES D.C.
Published: November 2004

We investigate the effect of tuning of the signal frequency in Brillouin induced four-wave mixing. We verify a number of theoretical predictions, and show that in the unstable regime the frequency of the phase conjugate is independent of the signal frequency.
STIMULATED BRILLOUIN SCATTERING IN THE PRESENCE OF EXTERNAL FEEDBACK
Authors: GAETA ALEXANDER L. , BOYD ROBERT W.
Published: November 2004

We investigate theoretically and experimentally the process of stimulated Brillouin scattering (SBS) in the presence of weak feedback in a single-mode optical fiber. The threshold for the occurrence of Brillouin oscillation can be considerably lower than the threshold for normal SBS. The spectrum of the emitted Stokes light exhibits an extreme narrowing near and above the oscillation threshold. The Stokes intensity is found to exhibit various types of periodic and stable behavior.
STIMULATED SCATTERING OF PICOSECOND OPTICAL PULSES IN THE PRESENCE OF SELF-FOCUSING
Authors: MILLER EDWARD J. , BOYD ROBERT W.
Published: November 2004

We have studied, for various states of polarization for the input beam, the properties of the backward-going wave generated by stimulated light scattering when 25-ps-long laser pulses are focused into CS 2. For the case of a circularly polarized input wave, the backward-going wave is generated by stimulated Rayleigh-wing scattering (SRWS). However, for the case of a linearly polarized input beam, strong filamentation occurs and the backward-going wave appears to be generated by stimulated librational scattering (SLS).
STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS AND TURBULENCE
Authors: BRZEŹNIAK Z. , CAPIŃSKI M. , FLANDOLI F.
Published: November 2004

Stochastic partial differential equations are proposed in order to model some turbulence phenomena. A particular case (the stochastic Burgers equations) is studied. Global existence of solutions is proved. Their regularity is also studied in detail. It is shown that the solutions cannot possess too high regularity.
SOME REMARKS ON THE COMPUTATION OF THE EIGENVALUES OF LINEAR SYSTEMS
Authors: ABDULLAH A.A. , LINDSAY K.A.
Published: November 2004

This paper has been prompted by some recent computations of eigenvalues of the Orr-Sommerfeld equation for very high Reynolds numbers. We have used a spectral analysis to emulate these calculations and our results have motivated some general remarks on the suitability of tracking and spectral methods as numerical eigenvalue schemes in the context of stability theory. Our remarks are further supported by illustrating the development of eigenvalues in the Magnetic Benard.
A PHASE PLANE ANALYSIS OF TRANSONIC SOLUTIONS FOR THE HYDRODYNAMIC SEMICONDUCTOR MODEL
Authors: ASCHER URI M. , MARKOWICH PETER A. , PIETRA PAOLA , SCHMEISER CHRISTIAN
Published: November 2004

We present an analysis of transonic solutions of the steady state 1-dimensional unipolar hydrodynamic model for semiconductors in the isoentropic case. The approach is based on construction of the orbits of the system in the electron density-electric field phase plane and on representation of discontinuous solutions of the hydrodynamic boundary value problem by a union of trajectory pieces. These pieces are related by shocks obeying jump and entropy conditions.

A continuation argument in the length of the semiconductor device under consideration is applied to construct a continuum of sub- and transonic solutions, which contains at least one solution for every positive length.

We also present numerical results illustrating the various possible solution profiles. For this we use a regularization of the problem, adding artificial diffusion to obtain singularly perturbed problems which are then solved numerically using continuation in the regularization parameter.
A DISCRETIZED MODEL FOR THE DYNAMICS OF A TETHERED SATELLITE SYSTEM AND APPLICATIONS
Authors: DE MATTEIS GUIDO , DE SOCIO LUCIANO M.
Published: November 2004

This paper deals with a simulation of a tethered satellite system where a discretized model of the cable is considered. The characteristics of a few space discretization procedures are compared while investigating the dynamics of two physically relevant models, namely the Space Pendulum and the Space String. The study of these limit problems provides a reference line for a better understanding of other more complex dynamic situations.
COUPLED FLOW IN POROUS-MATERIAL LINED PIPES
Authors: LUCHINI PAOLO , BASSANO EDMONDO
Published: November 2004

The slow motion of a fluid is studied in a duct of circular constant cross-section, whose internal wall is covered by a porous material permeable to the fluid, with an eye to the inlet phenomenon produced by arbitrary initial conditions at a given station. The coupled problem concerning the simultaneous Stokes flow in the central free region and Darcy flow in the porous layer is given an analytical solution based on a suitable eigenfunction expansion. The method is based on Van Kampen’s technique, which yields the coefficients of the expansion of arbitrary initial conditions in the eigenfunctions of a general, non-self-adjoint ordinary differential equation problem one at a time, with no need to invert systems of linear equations numerically. We have applied this approach to some examples, for this purpose developing suitable numerical procedures to evaluate the special functions we needed.
THE FREE STREAMING OPERATOR IN ASYMMETRIC SOBOLEV SPACES
Authors: BELLENI-MORANTE A.
Published: November 2004

Let T=−νy∂/∂x, |x|<a, |y|<1, be the streaming operator with non re-entry boundary conditions, under the assumption of plane symmetry. In an analogous way, let T1 be the free streaming operator with specular reflection boundary conditions.

We study some properties of T and T1, under the assumption that the domains D(T) and D(T1) are contained in suitable asymmetric Sobolev spaces. The norm of the element f is defined in such spaces by the sum ||f||=||f||1+c||∂f/∂x||1, where ||·||1 is the usual L1 norm and c is a constant.

We prove that both T and T1 generate contraction semigroups, which preserve positivity. Moreover, the semigroup generated by T1 also has a norm conservation property.

The results, listed above, are of interest for applications. In fact, in several evolution problems, one has to deal at the same time with T (or with T1) and with “local interaction” operators, such as the one examined in Sec. 7. These operators are bounded in the asymmetric Sobolev spaces which contain D(T) or D(T1), whereas they are not bounded in L1-like spaces.
A BOUNDARY APPROXIMATION METHOD FOR FOURTH ORDER PROBLEMS
Authors: COMODI M.I. , MATHON R.
Published: November 2004

We study approximate solutions of the biharmonic problem ∆2u=0, by a boundary approximation method for a class of given boundary conditions. We prove an O(n−r) error bound (in the space L2(Ω)) for the solution u belonging to Hr(Ω).
EXISTENCE AND ASYMPTOTIC BEHAVIOR IN PLANAR VORTEX THEORY
Authors: YANG JIANFU
Published: November 2004

The existence and the asymptotic behavior of solutions of a class of free boundary problems arising in planar vortex theory are discussed.
THE FOKKER-PLANCK OPERATOR AS AN ASYMPTOTIC LIMIT
Authors: POMRANING G.C.
Published: November 2004

It is shown that the Fokker-Planck operator describing a highly peaked scattering process in the linear transport equation is a formal asymptotic limit of the exact integral operator. It is also shown that such peaking is a necessary, but not sufficient, condition for the Fokker-Planck operator to be a legitimate description of such scattering. In particular, the widely used Henyey-Greenstein scattering kernel does not possess a Fokker-Planck limit.
EQUILIBRIUM PHASES AND LAYERED PHASE MIXTURES IN ELASTICITY
Authors: PODIO-GUIDUGLI PAOLO , CAFFARELLI GIORGIO VERGARA
Published: November 2004

In this paper an equilibrium phase is a restriction of a piecewise-affine deformation of a body to a (maximal, connected) subbody whose deformation is affine; a layered phase mixture is a continuous deformation that admits at least two distinct phases, separated by a plane interface. We study equilibrium phases and layered phase mixtures in the context of finite elasticity, in the presence of three different boundary conditions of traction: uniform pressure, and two other of null Lagrangians.

In Part I we reduce to a unique format the stationarity condition for the existence of equilibrium phases — of the conformal, transversely symmetric and asymmetric types — in elastic materials of arbitrary mechanical response; and we determine reasonable assumptions under which the stationary points of a (generalized) free energy are indeed equilibrium phases.

In Part II we restrict attention to isotropic material, and give explicit stationarity and compatibility conditions for the existence of mixtures of two layered, transversely symmetric phases.
ON THE PROBLEM OF HEAT CONDUCTION FOR RANDOM DISPERSIONS OF SPHERES ALLOWED TO OVERLAP
Authors: MARKOV KONSTANTIN Z. , CHRISTOV CHRISTO I.
Published: November 2004

We consider a random two-phase medium which represents a matrix containing an array of allowed to overlap spherical inclusions with random radii. A statistical theory of transport phenomena in the medium, on the example of heat propagation, is constructed by means of the functional (Volterra-Wiener) series approach. The functional series for the temperature is rendered virial in the sense that its truncation after the p-tuple term yields results for all multipoint correlation functions of the temperature field that are asymptotically correct to the order np, where n is the mean number of spheres per unit volume. The case p=2 is considered in detail and the needed kernels of the factorial series are found to the order n2. In this way not only the effective conductivity, but also the full statistical solution, i.e., all needed correlation functions, can be expressed in a closed form, correct to the said order.
A NONLINEAR PARABOLIC SYSTEM ARISING IN THERMOMECHANICS AND IN THERMOMAGNETISM
Authors: RODRIGUES JOSÉ-FRANCISCO
Published: November 2004

We consider a system of two parabolic equations modeling the thermo-convection of a Newtonian fluid, with temperature dependent viscosity of energy dissipation, as well as the thermal effects of the eddy currents, induced by a slowly varying magnetic field, in cylinders with arbitrary cross-section. We show the existence of a weak solution of the corresponding initial-boundary value problem and, under additional assumptions, we consider the question of the uniqueness and regularity of the solution.
NUMERICAL APPROXIMATION OF VISCOSITY SOLUTIONS OF FIRST-ORDER HAMILTON-JACOBI EQUATIONS WITH NEUMANN TYPE BOUNDARY CONDITIONS
Authors: ROUY ELISABETH
Published: November 2004

We present a general result concerning numerical approximations, obtained by finite difference schemes, of viscosity solutions to the Cauchy problem for first-order Hamilton-Jacobi equations with Neumann type boundary conditions. It states that if Δt is the time-discretization , then the error estimate between the approximation and the solution is of the order [Formula: see text] under certain assumptions of monotonicity and consistency on the numerical scheme.
SPECTRAL PROPERTIES OF AN ELASTIC ROD-SPRING COUPLED SYSTEM IMMERSED IN A FLUID
Authors: SANCHEZ-HUBERT J. , BÉRÉTÉ S. , PLANCHARD J.
Published: November 2004

The study of vibrations of elastic tube bundles immersed in a fluid is very important in Engineering, for example concerning the dynamical behavior of heat exchangers, nuclear reactor cores, etc. This paper is concerned with the investigation of the resonance frequencies when the number of rods is very high. That requires us to use the homogenization technique for modelling this coupled system by an equivalent continuous material. We then show that this equivalent system may have an essential spectrum.
A VISCOUS-INVISCID COUPLING UNDER MIXED BOUNDARY CONDITIONS
Authors: CANUTO C. , RUSSO A.
Published: November 2004

In this paper we consider a nonlinear modification of a linear convection-diffusion problem in order to get a pure convection equation where the original problem is convection dominated. We extend the results of previous papers by considering mixed Dirichlet/Oblique derivative boundary conditions.
ADAPTIVE FINITE ELEMENT METHODS FOR THE OBSTACLE PROBLEM
Authors: JOHNSON CLAES
Published: November 2004

We prove on a posteriori error estimate for a finite element method for an elliptic variational inequality with unilateral constraint. We formulate a corresponding adaptive method and prove reliability and efficiency of the method.
SOME ERROR ESTIMATES FOR WAVELET EXPANSION
Authors: BERTOLUZZA SILVIA
Published: November 2004

We give some error estimate for the approximation of a function by its wavelet expansion. Moreover we consider the numerical procedure introduced in Ref. 9 in order to compute the expansion of a function f with respect to a compactly supported wavelet basis, for which we give an error estimate in the Ws,p norm.
A HYBRID KNOWLEDGE ENGINEERING DEVELOPMENT ENVIRONMENT (KEDE)
Authors: ZHENG ZIJIAN , LI WEI
Published: November 2004

This paper presents a brief overview of knowledge-based system building tools. Then a hybrid knowledge engineering development environment called KEDE is described as a powerful toolkit for large AI problems. It provides five kinds of knowledge representations: extended frames, semantic nets, procedural knowledge, object-oriented technique, and predicate logic. Correspondingly, it supports: procedure-oriented, data-oriented, object-oriented, and logic-oriented programming. KEDE gains a very powerful inheritance mechanism using frames. It further provides an automatic retrieval technique for processing implicit knowledge, a demon mechanism for firing functions, a message-sending mechanism for activating methods, and two inference engines for backward, forward, and even mixed reasoning. All these facilities are tightly integrated and formed an entirety. KEDE has been implemented in Common Lisp on Sun workstations.
AN ORGANIZATIONAL FRAMEWORK FOR COOPERATING INTELLIGENT INFORMATION SYSTEMS
Authors: PAPAZOGLOU MIKE P. , LAUFMANN STEVEN C. , SELLIS TIMOS K.
Published: November 2004

There is a growing belief that the next generation of information processing systems will be based on the paradigm of Intelligent and Cooperative Information Systems (ICISs). Such systems will involve information agents — distributed over the nodes of a common communication network — which work in a synergistic manner by exchanging information and expertise, coordinating their activities and negotiating how to solve parts of a common information-intensive problem. Along with motivating the importance of such systems the paper gives an overview of related research areas, notably Distributed Artificial Intelligence (DAI) and Distributed Databases (DDBs), and presents a generic architecture which views an ICIS as a community of communicating and cooperating intelligent information agents.
ON INTELLIGENT AND COOPERATIVE INFORMATION SYSTEMS: A WORKSHOP SUMMARY
Authors: BRODIE MICHAEL L. , CERI STEFANO
Published: November 2004

Future information systems will involve large numbers of heterogeneous, intelligent agents distributed over large computer/communication networks. Agents may be humans, humans interacting with computers, humans working with computer support, and computer systems performing tasks without human intervention. We call such systems Intelligent and Cooperative Information Systems (ICISs). Although we can imagine extensions of capabilities of current ISs and of individual contributing core technologies, such as databases, artificial intelligence, operating systems, and programming languages, we cannot imagine the capabilities of ICISs which we believe will be based on extensions of these and other technologies. Neither do we know exactly what technologies and capabilities will be required, what challenges will arise, nor how the technologies might be integrated or work together to address the challenges.

In this paper, we provide initial definitions for key concepts and terms in this new area, identify potential core contributing technologies, illustrate the ICIS concept with example systems, and pose basic research questions. We also describe the results of discussions on these topics that took place at the Second International Workshop on Intelligent and Cooperative Information Systems held in Como, Italy, October 1991. The workshop focused on core technologies for ICISs. The workshop and the results reflect the multi-disciplinary nature of this omerging area.
GENERALIZING THE PARTIAL GLOBAL PLANNING ALGORITHM
Authors: DECKER KEITH S. , LESSER VICTOR R.
Published: November 2004

The distributed coordination problem can be described as "how should the local scheduling of activities at each agent be affected by non-local concerns and constraints?" Partial global planning (PGP) is a flexible approach to distributed coordination that allows agents to respond dynamically to their current situation. It is based on detecting relationships in the computational goal structures of the distributed agents. However, the detailed PGP mechanisms depend on the existence and availability of certain characteristics and structures that are idiosyncratic to the Distributed Vehicle Monitoring Testbed (DVMT). Generalized Partial Global Planning tries to extend the PGP approach by communicating more abstract and hierarchically organized information, detecting in a general way the coordination relationships that are needed by the partial global planning mechanisms, and separating the process of coordination from local scheduling. This new characterization of partial global planning has less communication overhead and can be more easily adapted and extended to new styles of problem solving and new multi-agent environments that have different characteristics from the original DVMT. This paper first describes the coordination problem as it was viewed by the PGP algorithm, and then extensions to that problem. It then briefly describes our model of task structures and coordination relationships. Finally, we show how the PGP algorithm, as an example, can be described using our method.
TOPOLOGICAL QUANTUM FIELD THEORIES ASSOCIATED TO FINITE GROUPS AND CROSSED G-SETS
Authors: YETTER DAVID N.
Published: November 2004

Using methods suggested by the work of Turaev and Viro [11, 12], we provide a detailed construction of topological quantum field theories associated to finite crossed G-sets. Our construction of theories associated to finite groups fills in some details implicit in Dijkgraaf and Witten's [3] discussion of topological gauge theories with finite gauge group, while the theories associated to finite crossed G-sets simultaneously extend Dijkgraaf and Witten's [3] results to 3-manifolds equipped with links and Freyd and Yetter's [5] construction of link invariants from crossed G-sets from links in the 3-sphere to links in arbitrary 3-manifolds. Topological interpretations of the manifold and link invariants associated to these TQFT's are provided. We conclude discussion of our results as a toy model for QFT and of their relation to quantum groups.
NEW SOLUTIONS OF YANG-BAXTER EQUATION AND NEW LINK POLYNOMIALS
Authors: CHENG YI , GE MO-LIN , LIU G. C. , XUE KANG
Published: November 2004

A new family of braid group representations associated with Lie algebras An, Bn, Cn and Dn is proved to be Birman-Wenzl algebra, then Yang-Baxterize them to trigonometric and rational solutions of YBE. New link polynomials are set up.
JONES POLYNOMIAL AS A POTTS MODEL PARTITION FUNCTION
Authors: WU F. Y.
Published: November 2004

It is shown that the Jones polynomial occurring in the theory of links as a knot invariant is expressible directly as the partition function of a vertex model and a q2-state Potts model. This formulation of the Jones polynomial, which makes use of the solution of the Yang-Baxter equation of a q-state vertex model considered previously by Perk and Wu, does not require the use of the writhe of the link as needed in previous statistical mechanical considerations.
SURFACES IN R4 OF BRAID INDEX THREE ARE RIBBON
Authors: KAMADA SEIICHI
Published: November 2004

Any closed oriented surface embedded in R4 is described as a closed 2-dimensional braid and its braid index is defined. We study 2-dimensional braids through a method to describe them using graphs on a 2-disk and show that braid index two surfaces in R4 are unknotted and braid index three surfaces are ribbon.
COMBINATORIAL CALCULATION OF THE VARIOUS NORMALIZATIONS OF THE WITTEN INVARIANTS FOR 3-MANIFOLDS
Authors: NEIL JOHN R.
Published: November 2004

Polynomial formulae for the Witten invariant of 3-manifolds for manifolds which bound plumbed 4-manifolds are developed via the combinatorial approach of Lickorish. A number of tables of calculations of the various normalizations of this invariant are presented for a variety of Seifert fiber spaces over S2.
EXPERIMENTAL IMPLEMENTATION OF A NEW CREATIVE METHOD TO SUPPORT FUTUROLOGY BY SMALL BUSINESSES IN A STRATEGIC MANAGEMENT PERSPECTIVE
Authors: CARRIER CAMILLE , COSSETTE PIERRE , VERSTRAETE THIERRY
Published: November 2004

Small businesses, like large corporations, are required to demonstrate creativity and innovation if they are to survive and flourish in a competitive and increasingly demanding world. Among other things, they must regularly and systematically explore major trends in their environment in order to detect possible business opportunities. The academic literature stresses the importance of this task but despite this, few researchers have, up to now, shown any interest in developing and assessing methods and tools to support businesses in their futurology efforts. This study is intended to correct this deficiency, at least partially; it defines a new method designed to assist small businesses in carrying out futurology in a strategic management perspective, and describes an experimental implementation of the method.
ENTREPRENEURSHIP CULTURE AND TECHNOLOGICAL STRATEGIC ALLIANCES BETWEEN COMPETITORS: FROM SAVING TRANSACTION COSTS TO COMMON KNOWLEDGE DYNAMICS
Authors: ALIOUAT BOUALEM
Published: November 2004

By combining the ideas of entrepreneurship and partnership, this paper deals with the core competencies (essentially through their cultural dimension) that firms have to develop with technological innovation in view. We are more particularly concerned with entrepreneurs who develop their business through strategic alliances with competitors. By analyzing managerial and cultural practices this paper proposes frameworks of core competencies which contribute to optimizing these alliances. We have carried out an empirical analysis of 60 technological alliances between firms. This study is based on interviews with top managers and entrepreneurs. The results show a scope of two different cases which depend on the creation or not of a common structure (joint venture or joint R&D structure). In the case of non-determinant technological projects, we have proposed flexible contracts. In opposite cases, we propose frameworks of common structures, which favor common knowledge as core competencies in alliances.
THE INDICATORS OF LOCUS OF CONTROL IN THE SMALL BUSINESS CONTEXT
Authors: LITTUNEN HANNU , STORHAMMAR ESA
Published: November 2004

There have been divergent opinions as to the suitability of the various indicators of locus of control in business management research. This study examines how the indicators of internal locus and strategic locus of control function in the small business context. The study examines first the interrelations between these indicators and then relation between each of the indicators and the firm's strategic factors. The indicators of locus of control differed from each other in their relation to external control. The indicator of strategic locus of control correlated with the firm's targets, strategic decision-making and success. On the other hand the indicator of internal locus of control is useful in research on entrepreneurship and the birth of new firms.
CRITICAL FACTORS INFLUENCING EMPLOYMENT: A STUDY OF SMALL MANUFACTURING FIRMS IN SOUTH-EAST AUSTRALIA
Authors: RAAR JEAN , SMITH ERIC , CUMMINGS KATH
Published: November 2004

Compliance with legislation has been highlighted as a factor influencing the reluctance of small and medium sized enterprises to take on new employees. With the objective of determining factors influencing smaller firms in their employment decisions, mailed questionnaires were used to survey small to medium manufacturing businesses in the Australian States of Victoria and New South Wales. Significant critical factors and deterrents to further employment were identified.
RESEARCH ON TECHNOLOGICAL INNOVATION AS SEEN THROUGH THE CHINESE LOOKING GLASS
Authors: DU YUXING , FARLEY JOHN U.
Published: November 2004

The rapid development of the Chinese economy during the 1990's has intensified research on technological innovation. Recent policy emphasis on innovation as a path to sustainable economic growth will only accelerate work on this important topic. The work by individuals and groups at various research institutes and universities has mainly been published in leading Chinese scholarly journals. In this paper, we develop a framework and do a substantive review of the literature to characterize the state of knowledge about technological innovation in China, with special emphasis on: 1) conceptual contributions, 2) empirical results, and 3) connections between innovation and performance.
THE IMPACT OF FINANCIAL PLANNING AND CONTROL ON PERFORMANCE OF SMEs IN AUSTRIALIA
Authors: WIJEWARDENA HEMA , DE ZOYSA ANURA
Published: November 2004

Although there has been some discussion in the academic literature on the relationship between planning and performance of small and medium enterprises(SMEs), no prior research has attempted to capture the control aspect of planning and its possible impact on performance. Furthermore, most of the studies on this aspect have been concentrating on long-range strategic planning with little attention being devoted to financial planning based on annual budgeting. Therefore, based on the results of a study involving a questionnaire survey of budgetting and budgetary control processes of 473 manufacturing SMEs in Australia, this paper attempts to provide an analysis of the impact of both financial planning and control of the sample firms on their performance. The results reveal that greater comprehensiveness in both financial plannig and control processes leads to higher sales performance of these firms.
ENTREPRENEURIAL SUCCESSION, FIRM GROWTH AND PERFORMANCE
Authors: BUTLER JOHN E. , PHAN PHILLIP H. , SAXBERG BORJE O. , LEE SOON HOON
Published: November 2004

This research examines business succession in small firms by presenting and testing a succession outcome decision model that is affected by the impact of family, performance, and strategy. Succession has been seen as an important issue in firms of all sizes, but the issue can be a much more personal one for entrepreneurs. Data were collected from a sample of 294 entrepreneurs using a questionnaire. These entrepreneurs were asked about the likelihood of various succession options, strategy, performance, and issues related to their family.

Results indicated that in firms where family members were seen as making a positive impact to the firm's performance, entrepreneurs were more likely to see family member succession as the likely outcome. Historical performance did not have much impact on succession decisions, although expectations of poor future performance made family succession a less likely envisioned outcome.
CONTEMPORARY PERSPECTIVES ON WOMEN'S ENTREPRENEURSHIP: A REVIEW AND STRATEGIC RECOMMENDATIONS
Authors: GUNDRY LISA K. , MIRIAM BEN-YOSEPH , POSIG MARGARET
Published: November 2004

The study of women's entrepreneurship has grown steadily during the last two decades, as the number of women-owned businesses worldwide has increased dramatically. This article presents an examination of major research questions and highlights the most recent scholarship on women's entrepreneurship within several key domains. The findings integrate broad areas of inquiry, including the emergence of women-owned firms in the global economy, entrepreneurial and firm characteristics, financing patterns, the greatest challenges to enterprise growth, and the influence of culture and family on the entrepreneurial organization. Recommendations are provided to contribute to an increased understanding of the dynamics of women-headed entrepreneurial enterprises around the world.