bluuebunny/crossref_metadata_2025 huggingface dataset:
MEAN-FIELD DYNAMICAL SEMIGROUPS ON C*-ALGEBRAS
Authors: DUFFIELD N.G. , WERNER R.F.
Published: July 2002

We study a notion of the mean-field limit of a sequence of dynamical semigroups on the n-fold tensor products of a C*-algebra [Formula: see text] with itself. In analogy with the theory of semigroups on Banach spaces we give abstract conditions for the existence of these limits. These conditions are verified in the case of semigroups whose generators are determined by the successive resymmetrizations of a fixed operator, as well as generators which can be approximated by generators of this type. This includes the time evolutions of the mean-field versions of quantum lattice systems. In these cases the limiting dynamical semigroup is given by a continuous flow on the state space of [Formula: see text]. For a class of such flows we show stability by constructing a Liapunov function. We also give examples where the limiting evolution is given by a diffusion, rather than a flow on the state space of [Formula: see text].
THE PRINCIPLE OF LOCALITY AND QUANTUM FIELD THEORY ON (NON GLOBALLY HYPERBOLIC) CURVED SPACETIMES
Authors: KAY BERNARD S.
Published: July 2002

In the context of a linear model (the covariant Klein Gordon equation) we review the mathematical and conceptual framework of quantum field theory on globally hyperbolic spacetimes, and address the question of what it might mean to quantize a field on a non globally hyperbolic spacetime. Our discussion centres on the notion of F-locality which we introduce and which asserts there is a net of local algebras such that every neighbourhood of every point contains a globally hyperbolic subneighbourhood of that point for which the field algebra coincides with the algebra one would obtain were one to regard the subneighbourhood as a spacetime in its own right and quantize — with some choice of time-orientation — according to the standard rules for quantum field theory on globally hyperbolic spacetimes. We show that F-locality is a property of the standard field algebra construction for globally hyperbolic spacetimes, and argue that it (or something similar) should be imposed as a condition on any field algebra construction for non globally hyperbolic spacetimes. We call a spacetime for which there exists a field algebra satisfying F-locality F-quantum compatible and argue that a spacetime which did not satisfy something similar to this condition could not arise as an approximate classical description of a state of quantum gravity and would hence be ruled out physically. We show that all F-quantum compatible spacetimes are time orientable. We also raise the issue of whether chronology violating spacetimes can be F-quantum compatible, giving a special model — a massless field theory on the “four dimensional spacelike cylinder” — which is F-quantum compatible, and a (two dimensional) model — a massless field theory on Misner space — which is not. We discuss the possible relevance of this latter result to Hawking’s recent Chronology Protection Conjecture.
CLASSIFICATION OF GAUGE-RELATED INVARIANT CONNECTIONS
Authors: BAUTISTA R. , MUCIÑO J. , NAHMAD-ACHAR E. , ROSENBAUM M.
Published: July 2002

Connection 1-forms on principal fiber bundles with arbitrary structure groups are considered, and a characterization of gauge-equivalent connections in terms of their associated holonomy groups is given. These results are then applied to invariant connections in the case where the symmetry group acts transitively on fibers, and both local and global conditions are derived which lead to an algebraic procedure for classifying orbits in the moduli space of these connections. As an application of the developed techniques, explicit solutions for SU (2) × SU (2)-symmetric connections over S2 × S2, with SU(2) structure group, are derived and classified into non-gauge-related families, and multi-instanton solutions are identified.
EXISTENCE AND NON-EXISTENCE RESULTS FOR WAVE OPERATORS FOR PERTURBATIONS OF THE LAPLACIAN
Authors: JENSEN ARNE , OZAWA TOHRU
Published: July 2002

Schrödinger operators with time-dependent potentials are studied. Necessary and sufficient conditions for existence of ordinary and Dollard-type modified wave operators are obtained. Sharp results for potentials with a specified leading term are obtained. Applications are given to the surfboard Schrödinger equation and to Stark Hamiltonians. In the latter case the discrepancy between classical and quantum scattering in dimension one is resolved.
THE τ FUNCTIONS OF THE AKS HIERARCHY AND TWISTOR CORRESPONDENCE
Authors: GUHA PARTHA
Published: July 2002

Adler–Kostant–Symes scheme provides a geometrical method for constructing different integrable systems. We construct an AKS hierarchy and obtain the τ function solutions of this hierarchy. We also show that this AKS hierarchy is a reduction of self dual Yang–Mills (SDYM) equation hierarchy and discuss its twistor construction. Hence we re-establish once again that SDYM hierarchy is a universal integrable hierarchy, so that by appropriate reduction and suitable choice of gauge group this hierarchy produces all the well-known hierarchies of the soliton equations 1.
PHASE TRANSITION OF A MODEL OF CRYSTALLINE MEMBRANE
Authors: KOIBUCHI HIROSHI , YAMADA MITSURU
Published: July 2002

We study two-dimensional triangulated surfaces of sphere topology by the canonical Monte Carlo simulation. The coordination number of surfaces is made as uniform as possible. The triangulation is fixed in MC so that only the positions X of vertices may be considered as the dynamical variable. The well-known Helfrich energy function S = S1 + bS2 is used for the definition of the model where S1 and S2 are the area and bending energy functions respectively and b is the bending rigidity. The discretizations of S1 and S2 are identical with that of our previous MC study for a model of fluid membranes. We find that the specific heats have peaks at finite bending rigidities and obtain the critical exponents of the phase transition by the finite-size scaling technique. It is found that our model of crystalline membranes undergoes an expected second order phase transition.
VERLET METHODS WITH STEPSIZE CONTROL FOR MOLECULAR DYNAMICS CALCULATIONS
Authors: MAZZONE A. M.
Published: July 2002

This study presents a stepsize control method for the numerical integration of ordinary differential equations. The method is based on the difference between a Verlet coordinates evaluation and an Adams–Bashforth coordinates predictor and can be easily implemented in existing Molecular Dynamics simulations. Numerical tests are made on the equilibrium configuration of crystalline silicon at low temperature.
Anti-Abortive Effect of Radix Scutellariae and Rhizoma Atractylodis in Mice
Authors: Zhong Xiu-Hui , Zhou Zhan-Xiang , Li Tie-Shuan , Wang En-Qiang , Shi Wan-Yu , Chu Su-Min
Published: July 2002

The objective of this study is to investigate the significance of natural killer (NK) cells and interleukin-2 in uterus in the early embryo loss (or resorption), and to elucidate the immunological modulation of maternal-fetal interface with Chinese herbal medicine Radix Scutellariae (Huang Qin) and Rhizoma Atractylodis (Bai Zhu). Lipopolysaccharide (LPS) was given via the tail vein to induce abortion in mice at day 7 of gestation. Uterine NK cells and IL-2 contents were analyzed by immunohistochemistry and enzyme linked immunosorbent assay (ELISA), respectively. The number of NK cells was found to be much higher (mean = 180 ± 39) in the decidua of LPS-treated abortion mice. But when the Chinese herbal medicine was used to prevent LPS-induced abortion, less NK cells (mean = 11 ± 4) were counted (p < 0.01). The mean value of IL-2 in LPS-treated mice was 5.25 ± 2.5938 pg/mg protein, higher than (p < 0.05) that of the herb prevention group, which was only 1.86 ± 0.9789 pg/mg protein. The results therefore indicate that the increase of NK cells in the decidua and IL-2 contents in the uterus in LPS-treated mice is closely related to the embryo loss, and that the Chinese herbal medicine prescription composed of Radix scutellariae and Rhizoma atractylodis has an anti-bortive effect through inhibition of maternal-fetal interface immunity.
DIVERGENCE STRUCTURE FOR THE STATISTICAL ENTROPY OF SPIN FIELDS IN REISSNER–NORDSTRÖM–de SITTER SPACE–TIME
Authors: LI ZHONG-HENG
Published: July 2002

We consider the divergences at all levels for the statistical entropy of gravitational, electromagnetic, neutrino and scalar fields on extremal and nonextremal Reissner–Nordström–de Sitter space–time background in terms of the brick-wall model. We find that entropy of spin fields within a region near coinciding horizons has higher divergence than usual. The earlier result that the entropy of spin fields is proportional to scalar one or the horizon area holds only for the thin region near an isolated horizon, since the spin-dependent divergences exist in all other cases.
THE 19-VERTEX MODEL AT CRITICAL REGIME |q|=1
Authors: KOJIMA TAKEO
Published: July 2002

We study the 19-vertex model associated with the quantum group [Formula: see text] at critical regime |q|=1. We give the realizations of the vertex operators in terms of free bosons and free fermions. Using these free field realizations, we present integral representations for the correlation functions.
THE ENTROPY CALCULATED VIA BRICK-WALL METHOD COMES FROM A THIN FILM NEAR THE EVENT HORIZON
Authors: LIU WENBIAO , ZHAO ZHENG
Published: July 2002

The brick-wall method put forward by 't Hooft has contributed a great deal to the understanding and calculating of the entropy of a black hole. However, there are some drawbacks in it such as little mass approximation, neglecting logarithm terms, and taking the term including L3as a contribution of the vacuum surrounding the black hole. Moreover, the fundamental problem is why the entropy of scalar field or Dirac field surrounding a black hole is the entropy of the black hole itself. It is well known that the event horizon is the characteristic of a black hole. The entropy calculation of a black hole should be only related to its horizon. Due to this analysis, we improve the brick-wall model by taking that the entropy of a black hole is only contributed by a thin film near the event horizon. This improvement not only gives us a satisfied result, but also avoids the drawbacks in the original brick-wall method. It is found that there is an intrinsic relation between the event horizon and the entropy. We also calculate the entropy of Schwarzschild–de Sitter space–time via the improved method, which can hardly be resolved via the original model.
QUANTUM CORRECTIONS TO NEUTRINO MASSES AND MIXING ANGLES
Authors: CHANKOWSKI PIOTR H. , POKORSKI STEFAN
Published: July 2002

Neutrino masses originate most likely at some high energy scale M≫MZ. To obtain reliable predictions for neutrino masses and mixing angles one has to take into account quantum corrections which, in cases of degenerate or partly degenerate neutrino spectra, can significantly change the pattern of the mixing angles. We review the calculation of these quantum corrections in the case in which the neutrino masses are effectively described by the single dimension 5 operator. In the framework of the Standard Model or its minimal supersymmetric extension we discuss both the corrections described by the renormalization group equations (RGE) and the low energy threshold corrections. We emphasize that the infrared fixed points of the RGE predict a relation between the mixing angles which is incompatible with the presently favoured LMA solution to the solar neutrino problem. We also show that in the MSSM the threshold corrections can lead to qualitatively different predictions for the mixing angles.
A HIGGS OR NOT A HIGGS? WHAT TO DO IF YOU DISCOVER A NEW SCALAR PARTICLE
Authors: BURGESS C. P. , MATIAS J. , POSPELOV M.
Published: July 2002

We show how to systematically analyze what may be inferred should a new scalar particle be discovered in collider experiments. Our approach is systematic in the sense that we perform the analysis in a manner which minimizes a priori theoretical assumptions as to the nature of the scalar particle. For instance, we do not immediately make the common assumption that a new scalar particle is a Higgs boson, and so must interact with a strength proportional to the mass of the particles with which it couples. We show how to compare different observables, and so to develop a decision tree from which the nature of the new particle may be discerned. We define several categories of models, which summarize the kinds of distinctions which the first experiments can make.
LATERAL OVERGROWTH OF DIAMOND FILMS ON METAL MASKED SUBSTRATE BY MICROWAVE PLASMA CHEMICAL VAPOR DEPOSITION
Authors: YAMAMOTO H. , NAOI Y. , FUJII Y. , SHINTANI Y.
Published: July 2002

We have grown laterally overgrown diamond films on stripe patterned silicon substrates by microwave plasma chemical vapor deposition. Titanium was used as the mask material and stripe patterns were fabricated using conventional photolithographic method. The selective growth area and the metal mask part order to enhance the crystal nucleation was performed before photolithographic process. SEM observation revealed that the diamond film was laterally overgrown on titanium mask. The result width of diamond film was 16 μm. The grain size on mask region was about three times as large as that g rown on nucleation region.
TRIBOLOGICAL AND MECHANICAL PROPERTIES OF ALUMINUM CONTAINING TETRAHEDRAL AMORPHOUS CARBON FILMS
Authors: Liu E. , Gao J. X. , Tay B. K. , Shi X. , Zeng A.
Published: July 2002

Tetrahedral amorphous carbon (ta-C) films which contained aluminum element were fabricated by filtered cathodic vacuum arc (FCVA) method. The tribological characteristics of the ta-C films were investigated with ball-on-disk tribometer. The increment of aluminum in the ta-C film leads to an increase of sp2 carbon bonding and a decrease of sp3 fraction in the film. The roughness of the films was measured with atomic force microscope, and the hardness and Young's modulus of the films were measured with nanoindentation. The results showed that the film hardness and Young's modulus dropped with the increase of Al content in the films. The results have been interpreted with respect to the change of sp 3 and sp 2 fractions in the ta-C:Al films.
CONTROL AND DIAGNOSTICS OF INDUCTIVELY COUPLED PLASMAS FOR CHEMICAL VAPOUR DEPOSITION ON NANOCOMPOSITE CARBON NITRIDE-BASED FILMS
Authors: TSAKADZE E. , OSTRIKOV K. , TSAKADZE Z. , JIANG N. , AHMAD R. , XU S.
Published: July 2002

Control and diagnostics of low-frequency (~ 500 kHz) inductively coupled plasmas for chemical vapor deposition (CVD) of nano-composite carbon nitride-based films is reported. Relation between the discharge control parameters, plasma electron energy distribution/probability functions (EEDF/EEPF), and elemental composition in the deposited C-N based thin films is investigated. Langmuir probe technique is employed to monitor the plasma density and potential, effective electron temperature, and EEDFs/EEPFs in Ar + N2 + CH4 discharges. It is revealed that varying RF power and gas composition/pressure one can engineer the EEDFs/EEPFs to enhance the desired plasma-chemical gas-phase reactions thus controlling the film chemical structure. Auxiliary diagnostic tools for study of the RF power deposition, plasma composition, stability, and optical emission are discussed as well.
Josephson Effects in Double-Layer Quantum Hall States
Authors: Iwazaki Aiichi
Published: July 2002

Under quite plausible assumptions on double-layer quantum Hall states with strong interlayer correlation, we show in general framework that coherent tunneling of a single electron between two layers is possible. It yields Josephson effects with unit charge tunneling. The origin is that Halperin states in the quantum Hall states are highly degenerate in electron number difference between two layers in the absence of electrons tunneling.
NEW APPROACH ON THE GENERAL SHAPE EQUATION OF AXISYMMETRIC VESICLES
Authors: HU ZHAN-NING
Published: July 2002

The general Helfrich shape equation determined by minimizing the curvature free energy describes the equilibrium shapes of the axisymmetric lipid bilayer vesicles in different conditions. It is a nonlinear differential equation with variable coefficients. In this letter, by analyzing the unique property of the solution, we change this shape equation into a system of the two differential equations. One of them is a linear differential equation. This equation system contains all of the known rigorous solutions of the general shape equation. And the more general constraint conditions are found for the solution of the general shape equation.
A STATISTICAL-FUZZY PERCEPTRON
Authors: ANDRECUT M.
Published: July 2002

An optimal statistical perceptron algorithm is derived using the Bayes classification theory. The described algorithm is able to construct an optimal classification hyperplane for separable and nonseparable classes. The described algorithm can be easily improved by imposing a simple fuzzyfication scheme of the training sets.
QUASIPERIODICITY AND CHAOS IN THE DC–DC BUCK–BOOST CONVERTER
Authors: EL AROUDI ABDELALI , BENADERO LUIS , TORIBIO ELIEZER , MACHICHE SALOUA
Published: July 2002

This paper is concerned with the study of nonlinear phenomena in a closed loop voltage-controlled DC–DC Buck–Boost converter when suitable parameters are varied. The dynamics is analyzed using both the continuous-time model and the numerically computed stroboscopic map. The analysis of the one-dimensional bifurcation diagram shows that Neimarck–Sacker bifurcation occurs at certain values of the parameters. Phase-locking periodic windows, the period-adding sequence, and transition from quasiperiodicity to period-doubling via torus breakdown are also obtained. The two-dimensional bifurcation diagram is carefully computed. This shows that phase-locking orbits produce so-called Arnold tongues in the parameter space. It is shown that the winding number plotted as a function of the bifurcation parameter is a devil's staircase. As typically occurs in general circle maps, the fine structures of the Arnold tongues and the devil's staircase show self-similarity.
TRAVELING WAVES IN CELLULAR NEURAL NETWORKS
Authors: HSU CHENG-HSIUNG , LIN SONG-SUN , SHEN WENXIAN
Published: July 2002

In this paper, we study the structure of traveling wave solutions of Cellular Neural Networks of the advanced type. We show the existence of monotone traveling wave, oscillating wave and eventually periodic wave solutions by using shooting method and comparison principle. In addition, we obtain the existence of periodic wave train solutions.
SPIRAL WAVES IN MEDIA WITH COMPLEX-EXCITABLE DYNAMICS
Authors: GORYACHEV ANDREI , KAPRAL RAYMOND
Published: July 2002

The structure of spiral waves is investigated in super-excitable reaction–diffusion systems where the local dynamics exhibits multilooped phase-space trajectories. It is shown that such systems support stable spiral waves with broken rotational symmetry and complex temporal dynamics. The main structural features of such waves, synchronization defect lines, are demonstrated to be similar to those of spiral waves in systems with complex-oscillatory dynamics.
A DYNAMIC INFERENCE MODEL FOR INTELLIGENT AGENTS
Authors: MIAO CHUNYAN , GOH ANGELA , MIAO YUAN , YANG ZHONGHUA
Published: July 2002

This paper proposes an Agent Inference Model (AIM) for constructing intelligent software agents. AIM has the ability of representing various types of fuzzy concepts, temporal concepts, and dynamic causal relationships between concepts. It also has the ability of handling feedback and analyzing inference patterns over different causal impact models. Based on AIM, a new type of intelligent agent, Dynamic Inference Agent (DIA) is presented. A dynamic inference agent has the ability to model, infer and make decisions on behalf of human beings. It uses numeric representations and computation instead of symbolic representation and logic deduction to represent knowledge and to carry out the inferences respectively. Thus the construction of DIA is simplified and the implementation code is compact. The application of DIA to various areas, especially for electronic commerce over the Internet is exemplified.
A METRIC-BASED APPROACH FOR PREDICTING CONCEPTUAL DATA MODELS MAINTAINABILITY
Authors: PIATTINI MARIO , GENERO MARCELA , JIMÉNEZ LUIS
Published: July 2002

It is generally accepted in the information system (IS) field that IS quality is highly dependent on the decisions made early in the development life cycle. The construction of conceptual data models is often an important task of this early development. Therefore, improving the quality of conceptual data models will be a major step towards the quality improvement of the IS development. Several quality frameworks for conceptual data models have been proposed, but most of them lack valid quantitative measures in order to evaluate the quality of conceptual data models in an objective way.

In this article we will define measures for the structural complexity (internal attribute) of entity relationship diagrams (ERD) and use them for predicting their maintainability (external attribute). We will theoretically validate the proposed metrics following Briand et al.'s framework with the goal of demonstrating the properties that characterise each metric. We will also show how it is possible to predict each of the maintainability sub-characteristics using a prediction model generated using a novel method for induction of fuzzy rules.
NORMAL FORMS FOR FREE APERIODIC SEMIGROUPS
Authors: McCAMMOND J. P.
Published: July 2002

The implicit operation ω is the unary operation which sends each element of a finite semigroup to the unique idempotent contained in the subsemigroup it generates. Using ω there is a well-defined algebra which is known as the free aperiodic semigroup. In this article we introduce a specific and rather elementary list of pseudoidentitites, we show that for each n, the n-generated free aperiodic semigroup is defined by this list of pseudoidentities, and then we use this identification to show that it has a decidable word problem. In the language of implicit operations, this shows that the pseudovariety of finite aperiodic semigroups is κ-recursive. This completes a crucial step towards showing that the Krohn–Rhodes complexity of every finite semigroup is decidable.
NONLOCAL BILINEAR EQUATIONS: EQUILIBRIUM SOLUTIONS AND DIFFUSIVE LIMIT
Authors: LACHOWICZ MIROSŁAW , WRZOSEK DARIUSZ
Published: July 2002

This paper deals with the qualitative analysis of a class of bilinear systems of equations describing the dynamics of individuals undergoing kinetic (stochastic) interactions. A corresponding evolution problem is formulated in terms of integro-differential (nonlocal) system of equations. A general existence theory is provided. Under the assumption of periodic boundary conditions and the interaction rates expressed in terms of convolution operators two classes of equilibrium solutions are distinguished. The first class contains only constant functions and the second one contains some nonconstant functions. In the scalar case (one equation) under suitable scaling, related to the shrinking of interaction range of each individual, the limit to the corresponding "macroscopic" equation is studied. The limiting equation turns out to be the (nonlinear) porous medium equation.
A FLOW-CONDITION-BASED INTERPOLATION MIXED FINITE ELEMENT PROCEDURE FOR HIGHER REYNOLDS NUMBER FLUID FLOWS
Authors: BATHE KLAUS-JÜRGEN , PONTAZA JUAN P.
Published: July 2002

We present a (somewhat) new finite element procedure for the analysis of higher Reynolds number fluid flows. While two-dimensional conditions and incompressible fluid flows are considered, the scheme can directly be used for three-dimensional conditions and also has good potential for compressible flow analysis. The procedure is based on the use of a nine-node element, optimal for incompressible analysis (the 9/3 or 9/4-c elements), and a Petrov–Galerkin formulation with exponential weight functions (test functions). These functions are established from the flow conditions along the edge- and mid-lines of the element. An important feature is that for low Reynolds number flow, the weight functions are the usual biquadratics and as higher Reynolds number flow is considered, the functions "automatically" skew so as to provide the necessary stability for the solution (the upwinding effect). Since the test functions are calculated by the flow conditions, no artificial constant is set by the analyst. The procedure is simple to implement. We present some solution experiences and conclude that while the procedure is not the "ideal" solution scheme sought, it has some valuable attributes and good potential for further improvements.
A SIMILARITY SOLUTION TO A PROBLEM IN NONLINEAR ION TRANSPORT WITH A NONLOCAL CONDITION
Authors: COHN STEVE , PFABE KRISTIN , REDEPENNING JODY
Published: July 2002

We derive an initial–boundary value problem with a nonlocal condition to model mass and charge transport in a controlled potential experiment called chronoamperometry. The charge is carried by ions set in motion by a change in the applied electrode potential. The resulting electric current is called the current response. When the charge flux arises from diffusion alone, the model reduces to an initial–boundary value problem for the heat equation. We consider diffusion and migration (motion under the influence of an electric field). This latter component of the total flux gives rise to a nonlinearity in the transport equations. Experimentalists have noted the current response to be proportional to the square root of the time with or without migration. It is shown that the initial–boundary value problem has a unique similarity solution that accounts for this observation.
TUMOR/IMMUNE SYSTEM COMPETITION WITH MEDICALLY INDUCED ACTIVATION/DEACTIVATION
Authors: FIRMANI B. , GUERRI L. , PREZIOSI L.
Published: July 2002

This paper deals with further developments of the kinetic modelling of the cellular dynamics of tumors interacting with an active immune defence system in the presence of cytokine signals. The contents is developed in the framework of the so-called cellular kinetic theory which leads to a modelling based on methods which are similar to those of nonlinear statistical mechanics. The model proposed here takes into account spontaneous activation of tumor cells and the effects of medical therapies aimed at deactivating the tumor and/or activating the immune system. The simulation presented shows that the possible scenarios that can be reproduced by the model are those experimentally observed.
FACE DETECTION AND VERIFICATION USING GENETIC SEARCH
Authors: BEBIS GEORGE , UTHIRAM SATISHKUMAR , GEORGIOPOULOS MICHAEL
Published: July 2002

We consider the problem of searching for the face of a particular individual in a two-dimensional intensity image. This problem has many potential applications such as locating a person in a crowd using images obtained by surveillance cameras. There are two steps in solving this problem: first, face regions must be extracted from the image(s) (face detection) and second, candidate faces must be compared against a face of interest (face verification). Without any a-priori knowledge about the location and size of a face in an image, every possible image location and face size should be considered, leading to a very large search space. In this paper, we propose using Genetic Algorithms (GAs) for searching the image efficiently. Specifically, we use GAs to find image sub-windows that contain faces and in particular, the face of interest. Each sub-window is evaluated using a fitness function containing two terms: the first term favors sub-windows containing faces while the second term favors sub-windows containing faces similar to the face of interest. Both terms have been derived using the theory of eigenspaces. A set of increasingly complex scenes demonstrate the performance of the proposed genetic-search approach.
IRREDUCIBILITY OF SOME QUANTUM REPRESENTATIONS OF MAPPING CLASS GROUPS
Authors: ROBERTS JUSTIN
Published: July 2002

The SU(2) TQFT representation of the mapping class group of a closed surface of genus g, at a root of unity of prime order, is shown to be irreducible. Some examples of reducible representations are also given.
ON CANONICAL GENUS OF FIBERED KNOT
Authors: NAKAMURA TAKUJI
Published: July 2002

In this note, we will give an infinite family of simple fibered knots of genus 3 whose canonical genus an arbitrarily large.
A GENERALIZED WIDTH FUNCTION OF FRACTAL RIVER NETWORK FOR THE CALCULATION OF HYDROLOGIC RESPONSES
Authors: WANG PENG-JUI , WANG RU-YIH
Published: July 2002

An approach to apply the fractal concept to estimate hydrologic response is proposed in this paper by matching suitable self-similar networks (SSNs) to a specific watershed, and modeling the runoff with a width-function based geomorphologic instantaneous unit hydrograph (WF-GIUH). In order to work out the identification between a specific basin and SSNs that are generated by an interior generator cooperating with an exterior generator, a generalized width function is derived. Subsequently, cumulative width functions on the basis of the derived function, as well as the informational entropies are used as criteria to decide the best patterns of the two cooperating generators for the specific watershed. The WF-GIUH model is then applied to calculate the runoff of this watershed as an outcome of the estimation. To assess the adaptability of the estimation model, San-Hsia watershed of Northern Taiwan is selected as a study area, where the analytical results of the outflow estimation indicate that the fractal algorithm has been implemented successfully for the calculation of hydrologic responses.
SOFTWARE RELIABILITY MODELS WITH TWO DEBUGGING RATES
Authors: GAUDOIN OLIVIER
Published: July 2002

A new class of software reliability models is proposed, based on practical considerations about the failure process and the influence of debugging on the successive software failure rates. It is assumed that, at each correction, a part of the previous software faults are removed and new faults can be introduced. Several well-known models belong to this class. With some additional assumptions, a simple model is proposed. The maximum likelihood equations for the estimation of its parameters are derived. The model is applied on real data and is compared to usual software reliability models.
ELECTRON-EXPOSURE EFFECTS ON DESORPTION OF F-(Cl-) AND (F+)(Cl+) IONS FROM ADSORBED CF2Cl2
Authors: LU Q.-B. , MADEY THEODORE E.
Published: July 2002

Electron-exposure effects on the desorption of F -( Cl -) and F +( Cl +) ions from 1 ML CF 2 Cl 2 /Ru(0001), 1 ML CF 2 Cl 2/1 ML Xe/Ru(0001) and 5 ML CF 2 Cl 2/Ru(0001) surfaces have been studied. It is observed that for a ≤1 ML CF 2 Cl 2/Ru surface, the anion yield shows a rapid decrease with increasing electron exposure, while the cation yield exhibits an increase. In contrast, an opposite behavior is observed for a 5 ML CF 2 Cl 2/Ru surface. For 1 ML CF 2 Cl 2 adsorbed on a 1 ML Xe-spacer layer, the effect tends to switch the behavior from the monolayer to the multilayer. These results indicate that Cl - ions accumulated on the multilayer or the monolayer surface on a Xe spacer by the polarization potential have an electrostatic effect on the desorption yields of anions and cations. Moreover, from the attenuation of the F - yield of a 1 ML CF 2 Cl 2-covered surface with electron exposure, the electron-induced dissociation is estimated to be 9.2(± 2.0) × 1016 cm 2.
METASTASIS OF AN ADENOCARCINOMA OF THE STOMACH TO THE 4TH METACARPAL BONE
Authors: Chang H. C. , Lew K. H. , Low C. O.
Published: July 2002

Metastatic tumours of the hand are uncommon. The majority of these tumours affect the phalanges and the primary tumours are usually bronchogenic in origin, with breast and kidney tumours next in frequency. Metastatic gastrointestinal to the hand is rare and usually from the colon. We report a case of poorly differentiated adenocarcinoma of the stomach antrum presenting with a metastatic lesion to the right 4th metacarpal bone. A review of the literature is included.
ANALYSIS OF EFFECT OF DETRENDING OF TIME-SCALE STRUCTURE OF FINANCIAL DATA USING DISCRETE WAVELET TRANSFORM
Authors: FLEMING BRIAN J. W. , YU DEJIN , HARRISON ROBERT G. , JUBB DAVID
Published: July 2002

One of the key features of wavelet analysis is its ability to decompose non-stationary signals according to time and scale. In this work, we use discrete wavelets to analyze the influence of detrending techniques on the time-scale information structure of daily financial data. We examine the use of log returns, a linear trend and the Hodrick–Prescott (HP) filter. Quantitative measurements of information distortion are given using the mean-squared error (MSE) and correlation of the wavelet coefficients between the detrended and original data. We find that log returns and linear detrending are most distortional. We also conclude that the HP-filter is most effective, depending on appropriate selection of the filter parameter, λ, which is [Formula: see text] for the given data set.
LEVEL SETS OF THE VALUE FUNCTION IN DIFFERENTIAL GAMES WITH THE HOMICIDAL CHAUFFEUR DYNAMICS
Authors: PATSKO V. S. , TUROVA V. L.
Published: July 2002

Three differential games with the dynamics of the homicidal chauffeur are considered. The first problem is the Isaacs' homicidal chauffeur differential game. In this game, a pursuer P minimises the capture time of an evader E. The objective of the evader is to prevent the capture or to maximise the capture time. The magnitude of the velocity is constant for the pursuer, and his maneuverability is bounded through a minimal turn radius. The maneuverability of the evader is not bounded. The pursuer's control is the rate of turn; the evader steers by choosing directions of his velocity. The main difference of the second problem is that the size of the constraint on the control parameter of the evader depends on the position of the game. The idea of such a modification was suggested by Bernhard. The third problem is a conic surveillance-evasion game studied by Lewin and Olsder. In this game, the dynamics is the same as in the Isaacs' problem, but the goals of the players differ from the classic formulation: an evader E minimises the time of escaping from a detection set that is a two-dimensional semiinfinite cone. The detection set is attached to the velocity vector of a pursuer P whose objective is to keep the evader within the detection set for maximal time. The paper describes the computation of level sets of the value functions for these games. The algorithm proposed by the authors is used. An analysis of families of semipermeable curves is carried out. The results of this analysis are used to check the correctness of the computation of level sets and to explain the appearance of holes in victory domains of the pursuer in the second problem.
PERFORMANCE ANALYSIS OF STATIC RA GROUPING TO REDUCE THE LOCATION TRAFFIC IN WIRELESS NETWORKS
Authors: LEE DONGCHUN
Published: July 2002

The terminal's Registration Area (RA) crossing within the Local Signaling Transfer Point (LSTP) area does not generate the traffic to the Home Location Register (HLR). The RAs in LSTP area are grouped statically. It is to remove the signaling overhead and to mitigate the Regional STP (RSTP) bottleneck which may occur in dynamic grouping method. Grouping RAs statically, I lessen the Inconsistency Ratio (ICR) when the caching method is applied to call tracking. The proposed scheme solves the HLR bottleneck due to the terminal's frequent RA crossings and removes the trade-off between call tracking cost and location registration cost to each of the LSTP area.
CORRELATION OF MECHANICAL BEHAVIOR AND MMP-1 PRESENCE IN HUMAN ATHEROSCLEROTIC PLAQUE
Authors: KILPATRICK DEBORAH , XU CHENGPEI , VITO RAYMOND , GLAGOV SEYMOUR
Published: July 2002

Regions of matrix metalloproteinase (MMP) activity potentially increase the susceptibility of the atherosclerotic lesion to complications associated with plaque rupture. Assessing the risk posed by this mechanism requires investigating the stress-strain environment associated with matrix metalloproteinase production in heterogeneous plaque. To this end, an experimental-computational technique was developed to perform mechanical analysis of physiologically loaded, diseased human aorta in vitro and to investigate relationships between vascular mechanics, histology, and histochemistry. Mechanical data and specimen histology were coupled through a heterogeneous finite element model, and tissue constituent material properties were determined by an optimization method. The cross-sectional distribution of MMP-1 was quantified using immunohistochemical techniques. Results show stresses and strains are strongly influenced by lesion structure and composition, and MMP-1 presence is correlated with histology and lesion mechanics. Interactions between lipid presence, mechanical stimuli, and extracellular matrix metabolism-catabolism likely affect arterial plaque remodeling, progression, and the risk of disruption and clinical symptoms.
AN ENHANCED GENETIC ALGORITHM FOR SOLVING THE HIGH-LEVEL SYNTHESIS PROBLEMS OF SCHEDULING, ALLOCATION, AND BINDING
Authors: GREWAL GARY WILLIAM , WILSON THOMAS CHARLES
Published: July 2002

This paper presents a novel approach to the concurrent solution of three High-Level Synthesis (HLS) problems that are modeled as a Constraint-Satisfaction Problem (CSP) and solved using an Enhanced Genetic Algorithm (EGA). We focus on the core problems of high-level synthesis: Scheduling, Allocation, and Binding. Scheduling consists of assigning of operations in a Data-Flow Graph (DFG) to control steps or clock cycles. Allocation selects specific numbers and types of functional units from a hardware library to perform the operations specified in the DFG. Binding assigns constituent operations of the DFG to specific unit instances. A very general version of this problem is considered where functional units may perform different operations in different numbers of control steps. The EGA is designed to solve CSPs quickly and does not require a user to specify appropriate mutation and crossover rates a priori; these are determined automatically during the course of the genetic search. The enhancements include a directed mutation operator and a new type of elitism that avoids premature convergence. The HLS problems are solved by applying two EGAs in a hierarchical manner. The first performs allocation, while the second performs scheduling and binding and serves as the fitness function for the second. When compared to other, well-known techniques, our results show a reduction in time to obtain optimal solutions for standard benchmarks.
A fast planar partition algorithm, II
Authors: Mulmuley Kentan
Published: July 2002

Randomized, optimal algorithms to find a partition of the plane induced by a set of algebraic segments of a bounded degree, and a set of linear chains of a bounded degree, are given. This paper also provides a new technique for clipping, called
virtual clipping
, whose overhead per window
W
depends logarithmically on the number if intersections between the borders of
W
and the input segments. In contrast, the overhead of the conventional clipping technique depends linearly on this number of intersections. As an application of virtual clipping, a new simple and efficient algorithm for plannar point location is given.
Project START
Authors: Kotov Vadim E.
Published: July 2002

When the Japanese Fifth Generation Computer project was launched in the early 1980s, data-processing professionals along with the world press were quick to appreciate the strategic goals and background ideas of the project which has since been referred to as “Japan's challenge.” Soon, next generation computing projects and programs, like MCC in the U.S., ESPRIT in Europe and ALVEY in Great Britain emerged as a response to this challenge.
Concurrency + modularity + programmability = MARS
Authors: Kotov Vadim E.
Published: July 2002

Modern, and particularly upcoming, technology makes it possible to design concurrent computers with a wide variety of architectures. The spectrum of applications requiring high-performance computer systems is also constantly growing. One might expect these two factors to cause a significant portion of the computer market to turn away from the traditional general-purpose mainframes in favor of the more diversified specialized proprietary machines. However, economic factors, production problems and maintenance and portability of software steer computer architects toward further unification and standardization of the design principles and components, and toward minimizing the number of proprietary computers.
Management of a remote backup copy for disaster recovery
Authors: King Richard P. , Halim Nagui , Garcia-Molina Hector , Polyzois Christos A.
Published: July 2002

A remote backup database system tracks the state of a primary system, taking over transaction processing when disaster hits the primary site. The primary and backup sites are physically isolated so that failures at one site are unlikely to propogate to the other. For correctness, the execution schedule at the backup must be equivalent to that at the primary. When the primary and backup sites contain a single processor, it is easy to achieve this property. However, this is harder to do when each site contains multiple processors and sites are connected via multiple communication lines. We present an efficient transaction processing mechanism for multiprocessor systems that guarantees this and other important properties. We also present a database initialization algorithm that copies the database to a backup site while transactions are being processed.
Biosphere 2 nerve system
Authors: Stewart Rocky L.
Published: July 2002

Biosphere 2 (Earth being Biosphere 1) is an experiment in closed system ecology. It is a steel and glass structure about the size of three football fields and has a volume of more than three million cubic feet. The purpose of the project is to demonstrate the viability of materially closed ecosystems—a sort of bioregenerative life support system—where water, air, and food are recycled. Later this year, eight people, called
Biospherians
, will be sealed inside Biosphere 2 for two years with only power and information being exchanged with the outside. A major part of this project is an expert system-based environmental control and monitoring system called the “Nerve System.”
LispView
Authors: Muller Hans
Published: July 2002

Although Lisp was the host for many of the first graphical user interface (GUI) packages, popular activity in this area has shifted to more primitive but widely used languages such as C and C++. One explanation for this shift is that while Lisp's strength in rapid prototyping and development led to the initial progress, it also tended to inspire an imperialist attitude: applications were often crafted exclusively in Lisp, even when part of the application could make use of an existing conventional language library. We believe the ideal way to construct a CommonLisp GUI package today is to integrate proven C libraries with an object-oriented Lisp framework.
The
Pan
language-based editing system
Authors: Ballance Robert A. , Graham Susan L. , Van De Vanter Michael L.
Published: July 2002

Powerful editing systems for developing complex software documents are difficult to engineer. Besides requiring efficient incremental algorithms and complex data structures, such editors must accommodate flexible editing styles, provide a consistent, coherent, and powerful user interface, support individual variations and projectwide configurations, maintain a sharable database of information concerning the documents being edited, and integrate smoothly with the other tools in the environment.
Pan
is a language-based editing and browsing system that exhibits these characteristics. This paper surveys the design and engineering of
Pan
, paying particular attention to a number of issues that pervade the system: incremental checking and analysis, information retention in the presence of change, tolerance for errors and anomalies, and extension facilities.
Massively distributed computing and factoring large integers
Authors: Silverman Robert D.
Published: July 2002

Over the last 15 years the increased availability of computers and the introduction of the RSA cryptosystem has led to a number of new and remarkable algorithms for finding the prime factors of large integers. Factoring numbers is an arithmetic problem so simple to understand that school children are asked to do it. While multiplying or adding two very large numbers is simple and can be done quite quickly, the age-old problem of trying to find a number that divides another number still has no simple solution. Computer science has reached a point where it is starting to custom tailor the design of computers toward solving specific problems. This pracnique will discuss some of the more recent algorithms for factoring large numbers and how networks of computers can be used to run these algorithms quickly. Since this is a general exposition, we do not give detailed mathematical descriptions of the algorithms. We also allow ourselves to be somewhat casual with mathematical notation in places and hope that the mathematically sophisticated will forgive the looseness.
Algorithm 708: Significant digit computation of the incomplete beta function ratios
Authors: Didonato Armido R. , Morris Alfred H.
Published: July 2002

An algorithm is given for evaluating the incomplete beta function ratio

I
x
(a,b)

and its complement

1 - I
x
(a,b)

. A new continued fraction and a new asymptotic series are used with classical results. A transportable Fortran subroutine based on this algorithm is currently in use. It is accurate to 14 significant digits when precision is not restricted by inherent error.
A VLSI decomposition of the deBruijn graph
Authors: Collins Oliver , Dolinar Sam , McEliece Robert , Pollara Fabrizio
Published: July 2002

The deBruijn graph

B
n

is the state diagram for an
n
-stage binary shift register. It has 2

n

vertices and 2

n
+ 1

edges. In this papers, it is shown that

B
n

can be built by appropriately “wiring together“ (i.e., connecting together with extra edges) many isomorphic copies of a fixed graph, which is called a
building block
for

B
n

. The efficiency of such a building block is refined as the fraction of the edges of

B
n

which are present in the copies of the building block. It is then shown, among other things, that for any α < 1, there exists a graph
G
which is a building block for

B
n

of efficiency > α for all sufficiently large
n
. These results are illustrated by describing how a special hierarchical family of building blocks has been used to construct a very large Viterbi decoder (whose floorplan is the graph

B
13

) which will be used on NASA's
Galileo
mission.
A graphical interval logic for specifying concurrent systems
Authors: Dillon L. K. , Kutty G. , Moser L. E. , Melliar-Smith P. M. , Ramakrishna Y. S.
Published: July 2002

This article describes a graphical interval logic that is the foundation of a tool set supporting formal specification and verification of concurrent software systems. Experience has shown that most software engineers find standard temporal logics difficult to understand and use. The objective of this article is to enable software engineers to specify and reason about temporal properties of concurrent systems more easily by providing them with a logic that has an intuitive graphical representation and with tools that support its use. To illustrate the use of the graphical logic, the article provides some specifications for an elevator system and proves several properties of the specifications. The article also describes the tool set and the implementation.