bluuebunny/crossref_metadata_2025_split huggingface dataset:
POLYNOMIAL INDEX GROWTH GROUPS
Authors: BALOG ANTAL , PYBER LÁSZLÓ , MANN AVINOAM 
Published: April 2003

We show that the order of a finite simple of Lie type is bounded by a small constant power of its exponent. This confirms, in a strengthened form, a conjecture of Vaughan-Lee and Zel'manov on the order and exponent of almost simple groups. We also obtain various structural restrictions on groups of polynomial index growth. Combining the above results we construct finitely generated residually finite groups of polynomial index growth which are neither linear nor boundedly generated. This answers questions of Segal and Platonov–Rapinchuk respectively. A further question of Platonov–Rapinchuk concerning a weakened polynomial index growth assumption is also answered.
BLOOD FLOW THROUGH A CIRCULAR PIPE WITH AN IMPULSIVE PRESSURE GRADIENT
Authors: PONTRELLI GIUSEPPE 
Published: April 2003

The unsteady flow of a viscoelastic fluid in a straight, long, rigid pipe, driven by a suddenly imposed pressure gradient is studied. The used model is the Oldroyd-B fluid modified with the use of a nonconstant viscosity, which includes the effect of the shear-thinning of many fluids. The main application considered is in blood flow. Two coupled nonlinear equations are solved by a spectral collocation method in space and the implicit trapezoidal finite difference method in time. The presented results show the role of the non-Newtonian terms in unsteady phenomena.
ADEQUACY OF LIMITED TESTING FOR KNOWLEDGE BASED SYSTEMS
Authors: MENZIES TIM , CUKIC BOJAN 
Published: April 2003

Knowledge-based engineering and computational intelligence are expected to become core technologies in the design and manufacturing for the next generation of space exploration missions. The literature is contradictory on how we are to assess such systems. Studies indicate significant disagreement regarding the amount of testing needed for system assessment. The sizes of standard black-box test suites are impractically large since the black-box approach neglects the internal structure of knowledge-based systems. On the contrary, practical results repeatedly indicate that only a few tests are needed to sample the range of behaviors of a knowledge-based program. In this paper, we model testing as a search process over the internal state space of the knowledge-based system. When comparing different test suites, the test suite that examines larger portion of the state space is considered more complete. Our goal is to investigate the trade-off between the completeness criterion and the size of test suites. The results of testing experiment on tens of thousands of mutants of real-world knowledge based systems indicate that a very limited gain in completeness can be achieved through prolonged testing. The use of simple (or random) search strategies for testing appears to be as powerful as testing by more thorough search algorithms.
A KNOWLEDGE-BASED METHOD FOR DERIVING CLASSES AND OBJECTS
Authors: LIU ALAN , SHR ARTHUR M. D. 
Published: April 2003

Identifying classes and objects in an object-oriented (OO) software development method requires a great amount of domain-specific knowledge and OO developing experiences to achieve the work. Experienced developers always have heuristic solutions to different problems. However, novice developers have difficulties developing their desired OO software systems. We propose a method that uses a knowledge-based system with the identification knowledge to support developers to obtain classes and objects that are suitable for one special domain problem. With the help of the identification knowledge, the developers can model the system easily and complete the rest of development work quickly.
FROM FRAMED LINKS TO CRYSTALLIZATIONS OF BOUNDED 4-MANIFOLDS
Authors: CASALI MARIA RITA 
Published: April 2003

It is well-known that every 3-manifold M3 may be represented by a framed link (L,c), which indicates the Dehn-surgery from [Formula: see text] to M3 = M3(L,c); moreover, M3 is the boundary of a PL 4-manifold M4 = M4(L, c), which is obtained from [Formula: see text] by adding 2-handles along the framed link (L, c). In this paper we study the relationships between the above representations and the representation theory of general PL-manifolds by edge-coloured graphs: in particular, we describe how to construct a 5-coloured graph representing M4=M4(L,c), directly from a planar diagram of (L,c). As a consequence, relations between the combinatorial properties of the link L and both the Heegaard genus of M3=M3(L,c) and the regular genus of M4=M4(L,c) are obtained.
COMBINATORICS AND FOUR BRIDGED KNOTS
Authors: MATIGNON DANIEL 
Published: April 2003

The ℝ P 3-Conjecture states a non-trivial knot in S 3 cannot yield ℝ P 3 by a Dehn surgery. Generically, in the knot-space S3-N(K), the intersection of a projective plane ℝP2 in ℝ P 3, and any 2-sphere S2 in S3 pierced by K, is a 1-complex which can be viewed as a graph in either the projective plane or the 2-sphere. Gordon and Luecke have used similar graphs arising as the intersection of two 2-spheres, to prove that a knot in S3 is determined by its complement. A part of this paper concerns some new combinatorial results on these graphs. They are considered as an unavoidable step towards showing that the ℝ P 3-Conjecture is true. Moreover, we use these results to prove that any non-trivial knot that could yield ℝ P 3 has at least five bridges.
THE STUDY OF PHOTON TRANSMISSION IN THE FABRY-PEROT INTERFEROMETER
Authors: GASCON F. , GALVAN A. 
Published: April 2003

This paper aims to study the phenomenon of light transmission through an interferometer by considering the passage of photons through the plates as a phenomenon of fractal percolation. In addition to the percolation of contacts, porous percolation, the percolation of points and the percolation of rebounds are also studied here (in the form described below).
PROJECTIONS OFF FRACTAL FUNCTIONS: A NEW VISION OF NATURE'S COMPLEXITY
Authors: PUENTE CARLOS E. , OBREGON NELSON , ROBAYO OSCAR , PUENTE MARTA G. , SIMSEK DEMIRAY 
Published: April 2003

The construction of a vast class of deterministic derived measures, defined as transformations of simple multinomial multifractals via fractal interpolating functions, is reviewed.1,2 It is illustrated that these objects, which are projections of unique measures defined over the graphs of fractal interpolating functions, provide a new vision to address the complexity of some of nature's tangled patterns over one and two dimensions, as they may be used to model: (a) Rainfall time series, (b) energy dissipation in fully developed turbulence, (c) two-dimensional contaminant plumes within a porous medium, and (d)"chaotic" and "stochastic" signals, as encountered in applications. A recently discovered universal connection between arbitrary measures with continuous cumulative distributions and the univariate and bivariate Gaussian distributions, via plane- and space-filling fractal interpolating functions respectively, is also reviewed.3,4 It is explained how this relationship yields (via projections) an infinite class of two-dimensional symmetric crystalline sets making up exotic kaleidoscopes of arbitrary symmetries, which decompose the bivariate Gaussian distribution.5 It is shown that these ideas enhance the vision that projections may be useful in approaching natural complexity, as some of these sets closely resemble key biochemical structures which even include life's own DNA rosette.
SELF-AFFINITY OF RECORDS OF FINANCIAL INDEXES
Authors: VALDEZ-CEPEDA RICARDO DAVID , SOLANO-HERRERA ENRIQUE 
Published: April 2003

One-dimensional profiles of financial indexes can be characterized by the statistical fractal dimension D, estimated through the slopes of the log-log geostatistical semivariograms, assuming that the relationships between the average variances and the time increments are described by a power law. This assumption corresponds to the concept of self-affinity. The industrial Dow Jones index is described by a D=1.332±0.11 indicating the persistence of trends along analyzed business 500 days period, while for almost the same period the German DAX Composite index (D = 1.688±0.026) is dominated by short-range variations, and the British Footsie (D=1.495±0.009) and the Australian Share Price (all ordinaries) (D=1.506±0.008) indexes have a behavior like the fractal Brownian motion (D=1.5). The Nikkei Cash index is characterized by a D=1.474±0.008 which implies that the short-range variation is almost as important as the long-term variation. Ds were evaluated by using scaling arguments, and multifractality was not evidenced.
CONJUGATED INFINITE ELEMENTS FOR TWO-DIMENSIONAL TIME-HARMONIC ELASTODYNAMICS
Authors: PINTO TIAGO , COYETTE JEAN-PIERRE 
Published: April 2003

Wave propagation problems in unbounded domains require the handling of appropriate radiation conditions (Sommerfeld). Various absorbing boundary conditions are available for that purpose. In a discrete finite element context, local and global Dirichlet-to-Neumann (DtN) and infinite element methods have shown their efficiency for the scalar wave equation. The paper concentrates on the extension of an infinite element method to the elastodynamic vector wave equation. The extension is developed in the frequency domain for 2-D problems. The paper focuses on the development of a conjugated formulation using the Helmholtz decomposition theorem of smooth vector fields. The accuracy of the developed formulation is assessed through the study of benchmarks. The computed results are shown to be in good agreement with the analytical solution for a multi-pole field along a circular cavity and with the results produced by other numerical methods.
THE SWAM'99 WORKSHOP — AN OVERVIEW
Authors: TOLSTOY A. , SMITH K. , MALTSEV N. 
Published: April 2003

The SWAM'99 (Shallow Water Acoustic Modeling, 1999) workshop on the topic of benchmarking shallow water range-dependent propagation modeling was held in Monterey CA in September No specific benchmarks were generated. Rather, each participant offered his (her) Transmission Loss curves for comparison with other results. This overview article will: • discuss the six (6) test cases; • discuss each individual's contribution to this benchmarking effort (see the associated articles in this Special issue for full details); • conclude with suggestions for future efforts.
MULTIPLICATIVE PADÉ PE FORMULATION APPLIED TO SWAM'99 TEST CASES
Authors: SEONG WOOJAE , CHOI BYUNGHO 
Published: April 2003

Accurate forward modeling of acoustic propagation is crucial in underwater sound applications that rely on coherent field predictions, such as source localization and geoacoustic inversion based on matched field processing concepts. As acoustic propagation in shallow water environments becomes important in recent years, range-dependent modeling due to environmental changes has to be considered of which parabolic equation (PE) method has received widespread use because they are accurate and relatively fast. In this paper, Seoul National University parabolic equation (SNUPE) employing a multiplicative Padé formulation is developed. Linearization of the depth direction operator is achieved via expansion into a multiplication form of Padé approximation. To approximate the depth directional equation, Galerkin's method is used with partial collocation to achieve computational efficiency. To approximate the range directional equation, Crank–Nicolson's method is used. Finally, numerical self-starter has been used to initiate the near-field solution. The Shallow Water Acoustic Modeling (SWAM'99) Workshop provides an opportunity to test SNUPE's accuracy and compare its results with others for a variety of synthetic environments. In this paper, the numerical implementation and accuracy of SNUPE is tested by comparing with RAM12 results for the SWAM'99 test cases. Numerical experiments for SWAM'99 test cases give satisfactory results in accuracy for SNUPE and show the importance of the bottom information in the shallow water acoustic modeling.
ANALYSIS OF THE REFLECTION AND TRANSMISSION COEFFICIENTS IN THREE-PHASE SANDSTONE RESERVOIRS
Authors: RAVAZZOLI CLAUDIA L. 
Published: April 2003

As it is well-known, seismic and acoustic data play a very important role in the characterization of hydrocarbon reservoirs. The correct interpretation of the anomalies observed in seismic wave velocities, quality factors and reflection coefficients in such environments makes necessary to use accurate models taking into account the main petrophysical features of the rocks. This also brings into play the importance of adequately describing the in situ properties of the reservoir fluids. This work investigates the influence of gas saturation and excess pore fluid pressure on wave energy splitting at plane interfaces within a Biot-type porous medium saturated by a liquid–gas mixture. Using laboratory measurements made on a wide variety of sandstones, we incorporate in the model the effective pressure dependence of rock matrix properties such as bulk and shear modulus, porosity and pore space compressibility. Also, using empirical laws, we estimate the properties of real hydrocarbon gases, oils and brines of different compositions under variable pressure and temperature conditions. We present analytical computations of the amplitude reflection and transmission coefficients to study the combined effect of the forementioned variables, aiming at a further AVA trend analysis.
A GENERALIZED MODE MATCHING METHOD FOR SCATTERING PROBLEMS WITH UNBOUNDED OBSTACLES
Authors: BONNET-BENDHIA A.-S. , TILLEQUIN A. 
Published: April 2003

The two-dimensional time-harmonic acoustic scattering by a semi-infinite waveguide composed of two parallel rigid plates is considered. An original mode matching method is developed to avoid the use of the Wiener–Hopf technique, generalizing usual mode matching methods to the case of unbounded media. A brief description of the method is given by means of Fourier decomposition leading to a well-posed variational problem with unknown being the trace of the solution on a well-chosen interface. From the numerical point of view, a local approximation is first considered by using Lagrange P1 finite elements on a segment of the interface. This leads to the computation of oscillatory integrals involving Fourier transform and complex square root functions. As a matter of accuracy, a special function is added to the finite element space, in order to take into account the asymptotic behavior of the solution. Finally, this method is extended to deal with local perturbations of the media by coupling the previous method to a classical integral one.
BENCHMARK SOLUTIONS FOR 3-D SCATTERING FROM CYLINDRICAL INCLUSIONS
Authors: TADEU ANTÓNIO J. B. , GODINHO LUIS M. C. , ANTÓNIO JULIETA M. P. 
Published: April 2003

The solutions for two-dimensional diffracting objects with simple geometry such as a cylindrical inclusion are frequently used as benchmark solutions to test the accuracy of numerical schemes, such as the Finite Elements Method and the Boundary Elements Method, and to better understand the wave propagation around inclusions. The importance of having benchmark solutions available is greater in the case of the evaluation of three-dimensional scattered fields, given its increase in complexity.In this work, analytical-numerical solutions are used to evaluate the three-dimensional wave field elicited by monopole sources in the vicinity of a fluid-filled cylindrical cavity drilled through an unbounded homogeneous elastic medium. This model is used to assess the effects of the position of the source and receiver, on the propagation of both axisymmetric and nonaxisymmetric wave modes. Both frequency versus axial-wave number responses and time-domain transients are presented.
INFORMATIONAL CAPACITY OF ACOUSTIC MEASUREMENTS
Authors: LICHMAN EUGENE 
Published: April 2003

Presented is the theoretical model for extracting the system response from measurements of the acoustic wave propagating through the linear system. Based on the results of this analysis, measurements are described as a convolution of the impulse response of the system with the mixed-phase-lag nonstationary forward wavelet (or source-generated wavefield). The source-generated wavefield includes all multiple terms generated within the system as well as the energy source signature and the detector characteristics. It is shown that the decay ratio of the source-generated wavefield can be used to separate the energy spectrum of the source-generated wavefield and the energy spectrum of the impulse response from the measurement function. The level of separability of energy spectrum of the source-generated wavefield and the impulse response reflects the amount of information about the measured system, which can be obtained from experimental data. In particular, if the source-generated wavefield does not decay during the propagation through the system, or, if the effective distance of the decay is comparable with the size of the measured system, the impulse response cannot be extracted from the result of measurements. Based on the theoretical conclusions, the computational procedure is proposed for one-dimensional deconvolution algorithm. The application of this algorithm is illustrated using seismic data as an example. The forward wavelet is extracted from seismic data itself. The deconvolution of data with the extracted wavelet provides surface-consistent scaling along with peg-leg and short-period multiples attenuation.
EARTHQUAKE GROUND MOTION SIMULATION THROUGH THE 2-D SPECTRAL ELEMENT METHOD
Authors: PRIOLO ENRICO 
Published: April 2003

The application of the 2-D Chebyshev spectral element method (SPEM) to engineering seismology problems is reviewed in this paper. The SPEM is a high-order finite element technique which solves the variational formulation of the seismic wave propagation equations. The computational domain is discretised into an unstructured grid composed by irregular quadrilateral elements. This property makes the SPEM particularly suitable to compute numerically accurate solutions of the full wave equations in complex media. The earthquake is simulated following an approach that can be considered "global", that is all the factors influencing the wave propagation — source, crustal heterogeneity, fine details of the near-surface structure, and topography — are taken into account and solved simultaneously. The basic earthquake source is represented by a 2-D point double couple model. Ruptures propagating along fault segments placed on the model plane are simulated as a finite summation of elementary point sources. After a general introduction, the paper first gives an overview of the method; then it concentrates on some methodological topics of interest for practical applications, such as quadrangular mesh generation, source definition and scaling, numerical accuracy and computational efficiency. Limitations and advantages of using a 2-D approach, although sophisticated such as the SPEM, are addressed, as well. The effectiveness of the method is illustrated through two case histories, i.e. the ground shaking prediction in Catania (Sicily, Italy) for a catastrophic earthquake, and the analysis of the ground motion in the presence of a massive structure.
ADVANCES IN MEDIA THEORY
Authors: OVCHINNIKOV SERGEI , DUKHOVNY ALEXANDER 
Published: April 2003

Media theory is a new branch of mathematical social and behavioral sciences with applications ranging from combinatorics to political sciences. Because of the generality of the concept of a medium and the natural character of its defining axioms, we believe the theory has a potential to become a new methodology for the management of imprecise, uncertain or incomplete information. In this paper, we review the basic concepts of media theory and present some advances in its combinatorial and stochastic parts. We prove that any medium is isomorphic to a submedium of a complete oriented medium and characterize these submedia. We also present some results concerning the stochastic evolution of a complete oriented medium and some of its submedia.
MENGER AND OVCHINNIKOV ON INDISTINGUISHABILITIES, REVISITED
Authors: TRILLAS ENRIC , CUBILLO SUSANA , CASTIÑEIRA ELENA 
Published: April 2003

In his paper "Probabilistic Theories of Relations", Menger showed that, in some cases, Prod-Indistinguishabilities are the same as the antilogarithms of distances; later, Ovchinikov obtained a characterization for Prod-Indistinguishabilities. In this note, Menger's result is included in a larger frame to obtain more Prod-Indistinguishabilities from distances, and Ovchinnikov's characterization is translated to distances in order to reach a larger class of them.
FINITE ELEMENT ANALYSIS OF THE SPACE CREATED BY SPLIT SPINOUS PROCESSES IN DOUBLE-DOOR LAMINOPLASTY TO OPTIMIZE SHAPE OF AN ARTIFICIAL SPACER
Authors: Hirabayashi Shigeru , Kumano Kiyoshi 
Published: April 2003

In double-door laminoplasty, several types of artificial spinous process spacers have been used instead of grafted bone from the iliac crest. However, inadequate contact between the spacer and the spinous process has recently been reported. From the observation during operation, we suspect that the main cause of the inadequate contact is the difference in shape between the spacer and the widened space created by the split spinous processes. The purpose of this study was to investigate the shape of the widened space by means of a finite element analysis in order to confirm our observation objectively and to provide a shape design of a spacer adapting to the space. Half-sectioned finite element models of the second cervical (C2) vertebra and the C6 vertebra were made from both the computed tomography (CT) of a clinical case and a plastic model of a cervical spine. The finite element model was designed to have almost the same size and shape as those of the genuine vertebra in the clinical case. Since cancellous bone and soft tissues were thought not to meaningfully influence the rigidity of the model, the model was made of only cortical bone with a thickness of 1.5 mm. The x-axis was defined as the lateral direction of the vertebral body, the y-axis as the anteroposterior direction of the vertebral body and the z-axis as the craniocaudal direction along the posterior margin of the vertebral body. The boundary conditions were fixed at the inner surface of the half-sectioned vertebral body. A force of 100 N was applied to the inner surface of the half-sectioned spinous process (to the cranial side and the caudal side, 50 N each) in the direction of the x-axis. The lateral deviation of each split spinous process was defined as the degree of deviation in the x-axis direction. The degree of lateral deviation of each split spinous process was analyzed in two types of models with and without making a lateral gutter 4 mm wide along the z-axis direction. The lateral deviation at the cranial side was larger than that at the caudal side in both the C2 and C6 vertebrae. The difference between the lateral deviation at the cranial side and the caudal side of each vertebra was larger in the type of model with the lateral gutter than in the type of model without it. It was confirmed that the shape of the widened space is trapezoidal in not only the axial but also frontal sections. In conclusion, the optimal shape of a spacer adapting to the widened space in double-door laminoplasty is trapezoidal in not only the axial but also frontal sections.