bluuebunny/crossref_metadata_2025 huggingface dataset:
STRANGE ATTRACTORS OF THE SHIL'NIKOV TYPE IN CHUA'S CIRCUIT
Authors: BLÁZQUEZ M. , TUMA E.
Published: November 2004

The chaotic behavior of the solutions of Chua's circuit is studied in the neighborhood of a homoclinic orbit to an equilibrium point of the saddle-focus type and in a neighborhood of two heteroclinic orbits to saddle-focus points which form a closed contour.
SYNTHESIZING SELF-SYNCHRONIZING CHAOTIC SYSTEMS
Authors: CUOMO KEVIN M.
Published: November 2004

A systematic approach is developed for synthesizing N-dimensional dissipative chaotic systems which possess the self-synchronization property. The ability to synthesize new chaotic systems further enhances the usefulness of synchronized chaotic systems for communications.
FINITE TIME BEHAVIOR OF SMALL ERRORS IN DETERMINISTIC CHAOS AND LYAPUNOV EXPONENTS
Authors: NICOLIS C. , NICOLIS G.
Published: November 2004

An extended formulation of sensitivity to initial conditions applicable to (small) finite errors and finite times is developed. It is shown that the first stages of error growth are neither exponential nor driven by the Lyapunov exponent.
CHAOTIC MIXING AND TRANSPORT IN WAVE SYSTEMS AND THE ATMOSPHERE
Authors: YANG HUIJUN
Published: November 2004

In this paper, we presented some results on chaotic mixing and transport in dynamical systems, particularly in wave systems and in the atmosphere. In wave systems, we studied chaotic mixing and transport in a perturbed traveling wave and in a perturbed stationary wave. We found that there is a fundamentally difference between the two cases. There can exist invariant KAM tori in perturbed traveling waves, and no such invariant KAM tori can be identified in perturbed stationary waves. The characteristics of mixing and transport in wave systems much depend on the perturbation structure. In some cases for both perturbed traveling waves and perturbed stationary waves, there exist porous barriers preventing rapid mixing and transport. The mechanism of chaotic mixing and transport is stretching and folding, which is shown to be the horseshoe mapping topologically. Global chaotic mixing and transport on the isentropic surface of the atmosphere was also studied. To better understand the generation of fine structure in the smooth velocity field and to gain an insight to chaotic mixing and transport, a color visualization method has been applied. Using different color pallets, we were able to emphasize different parts of the domain and obtained a wealth of information about the process. Several statistical characteristics methods have been introduced, including fractal dimension and the Lyapunov exponent. The probability distribution function and multifractal were also mentioned with application to chaotic mixing and transport. We then turned our attention to dynamically active mixing and transport. We discussed chaotic wave packet mixing and transport, describing two types of wave mixing and transport processes, i.e., dynamically passive wave mixing and dynamically active wave mixing. When the path of the wave packet is chaotic, we have chaotic wave packet mixing and transport. We showed that passive wave mixing and transport is described by the Lagrangian trajectory of the basic flow whereas dynamically active wave mixing and transport is described by the Lagrangian trajectory of wave packet. We found that there are two mechanisms in dynamically active wave mixing and transport. The first is advection by the medium flow; the second is the dispersion process, which is directly related to energy dispersion of the waves. Armed with the concept of dynamically active mixing and transport, we simulated the cloud pattern in the tropospheric atmosphere using an evaporation-transport-condensation model, and found it to be strikingly similar to cloud pictures taken by satellite.
BIFURCATIONS AND MIXING WINDOWS IN SINUSOIDAL CAVITY FLOW MIXING SYSTEMS
Authors: LING F. H. , SCHMIDT G.
Published: November 2004

Bifurcation analysis is applied to low periodic orbits of co- and counter-rotating sinusoidal cavity flow mixing systems, giving a quantitative account of the behavior observed and presenting an efficient way of finding nearly globally chaotic mixing systems, that can lead to uniform mixing. The corresponding parameter regions are called mixing windows. Symmetries of the Poincare maps deduced from those of continuous trajectories are used to help find periodic points. Both co- and counter-rotating flows have an integrable limit as T (the period of the sinusoidal motion of the walls) → 0. As T → ∞, most orbits in the co-rotating flows have an adiabatic invariant and are, therefore, regular, while the orbits in the counter-rotating flows do not, due to the existence of separatices. This qualitatively explains the better mixing performance of the counter-rotating flows compared with the co-rotating flows. The stream lines of the systems with small phase shift between the motion of two walls are nearly unchanged with time, and therefore, no good mixing can be expected. The bifurcation analysis reveals that a phase shift of half a period also results in bad mixing and that the best results are obtained with the phase shift of about a quarter period. The methodology presented in this paper saves computation time greatly compared with the traditional Poincare section method. Our results are compared with the existing experiments.
SPATIAL, TEMPORAL, AND GLOBAL MODE ENTROPY IN A THALAMO–CORTICAL NETWORK
Authors: WALLENSTEIN GENE V.
Published: November 2004

We employ an orthogonal decomposition technique with unique space–time symmetry properties to analyze a network of thalamo–cortical oscillators. A small number of thalamic "cells" are used to drive a network of cortical cells structured on a two-dimensional lattice. Two Bonhoeffer–van der Pol (BVP) based models of cortical neurons are compared at the network level in an attempt to reproduce some features of the thalamo–cortical system. It is shown that with the addition of a slowly varying term to the classical two-dimensional BVP model, the network can exhibit both periodic and irregular space–time behavior, along with changes in the temporal coherence and spatial frequency resembling the 8–12 Hz alpha rhythm.
THE EFFECT OF SMOOTHING ON THE DYNAMICAL BEHAVIOR OF NOISY CHAOTIC SIGNALS
Authors: TARROJA M. F. H. , SICAM V. A.
Published: November 2004

A smoothing, which has the effect of a Gaussian filter, has been performed on noisy chaotic digitized laser signals. It is shown that this smoothing can unravel distinguishing features of chaos in the phase space plots and first return maps and hence is useful in unambiguously differentiating chaos from noise. The calculation of the correlation dimensions reveal that the dynamics of the signals are not drastically affected by the smoothing. The type of smoothing discussed in this paper is useful in analyzing chaotic data sets corrupted by additive noise from the signal detection process.
TRIMODAL MAPS
Authors: LAMPREIA J. P. , RAMOS J. SOUSA
Published: November 2004

In this paper we present a result that establishes the admissibility rules for the symbolic sequences that are realizable as orbits of the critical points of three parameter families of maps on the interval with three critical points. We also introduce a method that simplifies the calculation of the topological entropy for these maps.
SAFETY-CRITICAL SOFTWARE: A RESEARCH AGENDA
Authors: BERZTISS ALFS T.
Published: November 2004

A system is safety-critical if failure of the system would result in loss of human life, personal injury, or significant material loss. Software that supports or supplants human control of safety-critical systems has to be highly reliable, but much research remains to be done before all the reliability-related issues of safety-critical software are fully understood. We discuss a research agenda under the following headings: completeness of requirements, readability of specifications, validation tools, validation of responsiveness, verification of implementations, software robustness, common-cause failures, reuse of reliable software, the software process, and ethical issues.
MEASUREMENT SUPPORT IN SOFTWARE ENGINEERING ENVIRONMENTS
Authors: LOTT CHRISTOPHER M.
Published: November 2004

The use of empirical data to understand and improve software products and software engineering processes is gaining ever increasing attention. Empirical data from products and processes is needed to help an organization understand and improve its way of doing business in the software domain. Additional motivation for collecting and using data is provided by the need to conform to guidelines and standards which mandate measurement, specifically the SEI’s Capability Maturity Model and ISO 9000–3. Some software engineering environments (SEEs) offer automated support for collecting and, in a few cases, using empirical data. Measurement will clearly play a significant role in future SEEs. The paper surveys the trend towards supporting measurement in SEEs and gives details about several existing research and commercial software systems.
MINIMUM-LINK C-ORIENTED PATHS: SINGLE-SOURCE QUERIES
Authors: ADEGEEST JOHN , OVERMARS MARK , SNOEYINK JACK
Published: November 2004

We consider paths composed of a minimum number of line segments parallel to a fixed set of c orientations that avoid a set of obstacles in the plane. We preprocess n line segment obstacles with disjoint interiors and a starting point A into a data structure using O(cn) space. With this data structure, we can determine the minimum number of line segments l of a path from A to a query point B in O(c log n) time and construct a path in additional O(l) time. Preprocessing takes O(c2n log n) time and space or O(c2n log 2 n) time and O(c2n) space. Usually c is a constant — as an example, c = 2 for rectilinear paths.
LOCAL ROBUSTNESS AND ITS APPLICATION TO POLYHEDRAL INTERSECTION
Authors: STEWART A. JAMES
Published: November 2004

The field of solid modeling makes extensive ve use of a variety of geometric algorithms. When implemented on a computer, these algorithms often fail because the computer only provides floating point arithmetic, while the algorithms are expecting infinite precision arithmetic on real numbers. These algorithms are not robust.

This paper presents a formal theory of robustness. It is then argued that the elegant theoretical approach to robustness is not viable in practice: algorithms like those used in solid modeling are generally too complex for this approach. This paper presents a practical alternative to the formal theory of robustness; this alternative is called local robustness.

Local robustness is applied to the design of a polyhedral intersection algorithm, which is an important component in many solid modelers. The intersection algorithm has been implemented, and, in extensive tests, has never failed to produce a valid polyhedron of intersection. A concise characterization of the locally robust intersection algorithm is presented; this characterization can be used to develop variants of the intersection algorithm, and to develop robust versions of other solid modeling algorithms.
GEOMETRIC MODELLING AND ALGORITHMS FOR BINARY MIXTURES
Authors: LACOLLE B. , SZAFRAN N. , VALENTIN P.
Published: November 2004

We present some computational methods in a particular case of mixing and separation theory, as an application of classical results in the field of computational geometry. Our aim is the production of some given mixtures by mixing parts of basic products. In the geometrical approach we use, products or mixtures are characterized by vectors and the mixing process by vector sums, in the vector space of physico-chemical species. The feasibility of a mixture is viewed as a point-inclusion in the convex set of mixtures which is a zonotope associated with basic mixtures. This paper is concerned with binary mixtures characterized by two species. The geometrical approach leads to plane geometry problems and gives complete solutions to the optimal fabrication of a mixture, as well as to the fabrication of a sequence of several mixtures. Using the framework of computational geometry, we present efficient algorithms for solving the main problems related to the management of binary mixtures.
HOW TO DRAW A SERIES-PARALLEL DIGRAPH
Authors: BERTOLAZZI PAOLA , COHEN ROBERT F. , DI BATTISTA GIUSEPPE , TAMASSIA ROBERTO , TOLLIS IOANNIS G.
Published: November 2004

Upward and dominance drawings of acyclic digraphs find important applications in the display of hierarchical structures such as PERT diagrams, subroutine-call charts, and is-a relationships. The combinatorial model underlying such hierarchical structures is often a series-parallel digraph. In this paper the problem of constructing upward and dominance drawings of series-parallel digraphs is investigated. We show that the area requirement of upward and dominance drawings of series-parallel digraphs crucially depends on the choice of planar embedding. Also, we present efficient sequential and parallel algorithms for drawing series-parallel digraphs. Our results show that while series-parallel digraphs have a rather simple and well understood combinatorial structure, naive drawing strategies lead to drawings with exponential area, and clever algorithms are needed to achieve optimal area.
THE WORD PROBLEM FOR SOME VARIETIES OF SOLVABLE LIE ALGEBRAS
Authors: KHARLAMPOVICH O. , GILDENHUYS D.
Published: November 2004

The word problem is said to be solvable in a variety of Lie algebras if it is solvable in every algebra, finitely presented in this variety. Let [Formula: see text] denote the variety of (2-step nilpotent)-by-abelian Lie algebra and [Formula: see text] the variety of abelian-by-(2-step nilpotent) Lie algebras. It is proved that the word problem is unsolvable in the “interval” of varieties containing the variety [Formula: see text] (of centre-by-[Formula: see text] Lie algebras over a field of characteristic zero), and contained in the variety [Formula: see text].
A NORMAL FORM FOR THE FREE LEFT DISTRIBUTIVE LAW
Authors: DEHORNOY PATRICK
Published: November 2004

We construct a new normal form for one variable terms up to left distributivity. The proof that this normal form exists for every term is considerably simpler than the corresponding proof for the forms previously introduced by Richard Laver. In particular the determination of the present normal form can be made in a primitive recursive way.
A PARALLEL ALGORITHM FOR THE HADAMARD PRODUCT OF HOLONOMIC FORMAL SERIES
Authors: BERTONI A. , MASSAZZA P.
Published: November 2004

In this work we consider the class of the holonomic formal series and we study how, given two linear differential equations with polynomial coefficients verified by two holonomic series Φ1 and Φ2, it is possible to compute a linear differential equation satisfied by the Hadamard product of Φ1 and Φ2. We give a parallel algorithm for this problem and we show that it belongs to NC 2.
POSSIBILITY OF RESONANCE RECORDING OF A CHARGE DENSITY GRATING IN AC ELECTRIC FIELD
Authors: DOOGHIN A.V. , ZEL’DOVICH B. YA.
Published: November 2004

Application of large amplitude asymmetric AC electric field to a photorefractive crystal and illumination by a slowly running sinosoidal interference pattern may lead to resonant recording of a running grating. The resonance corresponds to the excitation of a variant of the traps recharge wave. We propose mechanism of wave generation and analyze wave direction, amplitude, frequency in the case when the period of field oscillations is much smaller than the grating record time.
RECORDING OF A RUNNING GRATING BY A STANDING INTERFERENCE PATTERN IN A PHOTOREFRACTIVE CRYSTAL
Authors: LIBERMAN V.S. , ZEL’DOVICH B.YA.
Published: November 2004

In contrast to the previously reported phase-locked detection scheme, we suggest the recording of a running grating exp (iqx—iΩt) of charge density in a photorefractive crystal when the interference pattern exp (iqx) is a standing one. It may be achieved by application to the crystal of an electrical field which contains both DC and AC components. Coincidence of AC frequency Ω with that of charge density waves for the given E DC and q results in a resonant enhancement of the process.
CONVERTING 10 kW MULTI-MODE FIELDS INTO A SINGLE SPATIAL MODE WITH A SEMILINEAR PHASE CONJUGATE MIRROR
Authors: JAATINEN E. , LUTHER-DAVIES B.
Published: November 2004

We report on the use of a semilinear phase conjugate mirror to convert 20 % of the power contained in the 10 kW 20 ns pulses emerging from a multi-mode fibre back into a single spatial mode. This use of a phase conjugate mirror to unscramble phase distortions is unusual as only a single pass of the phase aberrating object is required. We also discuss the limitations of the technique that were encountered at high intensities ( MW/cm 2).
INTERACTION GEOMETRIES OF SELF PUMPED PHASE-CONJUGATING SBS CELLS
Authors: KUMMROW A.
Published: November 2004

Focused beam SBS cells and waveguide geometry are compared expanding the light wave into transverse modes, allowing for an analytical discussion. Waveguides give poor fidelity when used without aberrators to homogenize the intensity distribution over the light pipe cross section. Focused beam SBS cells can phase-conjugate single transverse mode pump waves without the help of aberrators. The calculated fidelity of about 0.6 for pumping with the fundamental mode is nearly constant from threshold up to more than 70% reflection. The beam constriction factor is β=0.7 resulting in a 1.4-times diffraction limited reflected beam.
NONLINEAR ORGANIC MOLECULES AND MATERIALS FOR OPTOELECTRONIC DEVICES
Authors: LEDOUX I. , ZYSS J.
Published: November 2004

The development of important applications related to optical telecommunications and optical signal processing rely increasingly on nonlinear optical phenomena underlying these optical functions such as frequency conversion and modulation, amplification and emission, multiplexing and directional switching, optical logical gates, and others. This will depend on the design, elaboration and availability of new materials displaying enhanced nonlinearities to be subsequently integrated into waveguiding devices. Organic materials are noteworthy candidates in this context, provided their microscopic and macroscopic properties are properly optimized with respect to the type of application required. Among the key-factors in the development of these materials are the quasi-unlimited variety of molecular structures accessible by organic synthesis, the possibility to connect specific nonlinear properties to other kinds of functionalities which are of crucial importance for the development of commercial devices (e.g., compatibility with other materials used in integrated optical circuits such as semi-conductors), and their exceptionally large second-order, non-resonant nonlinear response. Such performances are strongly dependent on a better understanding of the ‘molecular engineering’, rules, correlating molecular structures to their nonlinear optical properties towards optimization of the microscopic second order polarizabilities β and third-order polarizabilities γ. We will present in the following some examples of the most recent developments of highly efficient nonlinear molecules, ranging from purely one-dimensional structures such as polyenes to fully three-dimensional systems, taking full advantage of the tensorial character of the microscopic or macroscopic susceptibility tensors.
RECENT DEVELOPMENT IN POLYDIACETYLENE SYNTHESIS: UNCONVENTIONAL POLYDIACETYLENES FOR NLO APPLICATIONS
Authors: OGAWA T.
Published: November 2004

Unconventional methods to obtain thin films of polydiacetylenes are described. These methods include preparation of films of polydiacetylene containing polymers, the preparation of polydiacetylene microcrystals dispersed in common polymers and the polymerization of diacetylenes in the molten state. It was shown that highly transparent thin films having χ(3) values of the order of 10−9 to 10−10 esu can be obtained from these materials simply by spin coat casting followed by irradiation or thermal polymerization of the diacetilenes in the polymers, or by irradiation at temperatures above the melting points, for the diacetylenes which undergo polymerization in the molten state. The important advantage of such methods is the simplicity of their processing into thin films. There is a good possibility of increasing the χ(3) values and improving the optical quality of the film by molecular designing and by further experimentation with the preparation conditions.
THIRD-ORDER NONLINEAR OPTICAL INTERACTIONS IN TETRABENZPORPHYRINS
Authors: RAO D.V.G.L.N. , ARANDA F.J. , REMY D.E. , ROACH J.F.
Published: November 2004

Third-order nonlinear optical susceptibility χ(3) was measured for a variety of tetrabenzporphyrin compounds in solution in tetrahydrofuran at 532 nm using the technique of degenerate four-wave mixing. High values in the range 10−9 to 10−8 esu are observed. The dominant contribution comes from the imaginary part as a result of excited state absorption. Measurements were also made on thin films, deposited by the Langmuir-Blodgett technique, for one of the compounds. Mirrorless all-optical bistability induced by reverse saturable absorption was observed. These materials are good candidates for some applications in photonics technology.
ON THE ELLIPTIC-HYPERBOLIC COUPLING I: THE ADVECTION-DIFFUSION EQUATION VIA THE χ-FORMULATION
Authors: CANUTO C. , RUSSO A.
Published: November 2004

An advection-diffusion equation is considered, for which the solution is advection-dominated in most of the domain. A domain decomposition method based on a self-adaptive, smooth coupling of the reduced advection equation and the full advection-diffusion equation is proposed. The convergence of an iteration-by-subdomain method is investigated.
A BOUNDARY VALUE PROBLEM IN GROUNDWATER MOTION ANALYSIS — COMPARISON OF PREDICTIONS BASED ON DARCY’S LAW AND THE CONTINUUM THEORY OF MIXTURES
Authors: MUNAF D. , WINEMAN A.S. , RAJAGOPAL K.R. , LEE D.W.
Published: November 2004

The classical problem of the radial flow to a well in a confined horizontal aquifer is solved using two theories: (1) when the flow is based on Darcy’s law, and (2) when the flow is based on equations of the Continuum Theory of Mixtures. The latter reduce to Darcy’s law when the inertia of the fluid can be neglected, and when the viscosity of the fluid does not enter into the expression for the partial stress for the fluid. A comparison of the two solutions shows that there are conditions when Mixture Theory could predict results that provide a significant departure from those predicted by Darcy’s Law.

In this paper we delineate the extent of validity of Darcy’s law, within the context of a more general theoretical framework. The results of our work indicate that Darcy’s law is indeed quite good for low flow rates for a fluid like water. However this is not the case for dense fluids, say oils or effluents, due to the inclusion of inertial effects in the equations of motions.
THE SEMICONTINUOUS BOLTZMANN EQUATION FOR GAS MIXTURES
Authors: PREZIOSI L.
Published: November 2004

This paper proposes a semicontinuous model of the Boltzmann equation to describe the behavior of a mixture of P gases. The semicontinuous Boltzmann equation is a model in which gas particles can move in the plane in all possible directions, but with a finite number of velocity moduli. The model consists of a system of integro-differential equations with one-fold integrals over a suitable angular variable. Thermodynamic equilibrium is studied in details showing that the Maxwellian equilibrium states are uniquely defined in terms of the masses of the components of the mixtures and of the overall momentum and energy.
ON A PARABOLIC EQUATION WITH NON-LOCAL BOUNDARY CONDITION
Authors: GIANNI ROBERTO
Published: November 2004

Existence and uniqueness theorems are proved for a parabolic equation satisfying various kinds of non-local boundary conditions. Applications of these results are made to the physical situation in which a non-metallic conductor is in contact with a perfect conductor or with a well stirred fluid, and the conductor (or the fluid) is allowed to undergo a change of phase.
ABCDL: AN ACTOR-BASED CONCURRENT DISTRIBUTED LANGUAGE
Authors: ADORNI GIOVANNI , POGGI AGOSTINO
Published: November 2004

In this paper, we present a distributed object-oriented language, ABCDL, which has proved to be a suitable tool for the definition and implementation of distributed artificial intelligence systems. ABCDL is based on two different entities: actors and channels. An actor is a computational entity which performs some actions in response to incoming communications. An actor can also display a distributed behavior. In this case, it is composed of a set of other actors (distributed or not) synchronized by channels. A channel is a synchronization entity which sends a message to an (output) actor on the basis of the messages received from a set of (input) actors. The sending of this message does not depend only on the receipt of the input messages, but also on their contents. ABCDL permits the integration between hierarchical and distributed descriptions, allowing the definition of models at different levels of detail and abstraction. The separation between computation (managed by sequential actors) and synchronization (managed by channels) permits the user to obtain descriptions which offer good readability and good reusability of its sub-parts. Examples of the use of the language are discussed through the paper.
A MARKER-PASSING ALGORITHM FOR REFERENCE RESOLUTION
Authors: CHA SEUNGHO , MOLDOVAN DAN
Published: November 2004

Reference is a linguistic process by which a speaker/ writer denotes an entity. It is an important phenomenon in natural language, and it has been addressed by many researchers. A local focus constitutes important information used in reference resolution; however, the previous focusing approaches fail to resolve some references due to several problems. This paper presents a marker-passing solution and some experimental results. Reference resolution is carried out based on the premise that “the most active concept acceptable syntactically and semantically as a referent is the referent.” Referability is defined based on constraints and activeness to be used to compute the correct referent. This model has been implemented on a marker-passing simulator, and it shows 92.2% success rate and better performance than previous approaches in a set of arbitrarily chosen 100 news articles.
HEURISTIC CLASSIFICATION OF OFFICE DOCUMENTS
Authors: HAO XIAOLONG , WANG JASON T.L. , BIEBER MICHAEL P. , NG PETER A.
Published: November 2004

Document Processing Systems (DPSs) support office workers to manage information. Document classification is a major function of DPSs. By analyzing a document’s layout and conceptual structures, we present in this paper a sample-based approach to document classification.

We represent a document’s layout structure by an ordered labeled tree through a procedure known as nested segmentation and represent the document’s conceptual structure by a set of attribute type pairs. The layout similarities between the document to be classified and sample documents are determined by a previously developed approximate tree matching toolkit. The conceptual similarities between the documents are determined by analyzing their contents and by calculating the degree of conceptual closeness. The document type is identified by computing both the layout and conceptual similarities between the document to be classified and the samples in the document sample base. Some experimental results are presented, which demonstrate the effectiveness of the proposed techniques.
ILLUSTRATION OF A DECISION TABLE TOOL FOR SPECIFYING AND IMPLEMENTING KNOWLEDGE BASED SYSTEMS
Authors: VANTHIENEN J. , DRIES E.
Published: November 2004

In this paper it is explained how automated decision table construction and interfacing can prevent a great deal of the current problems with knowledge based systems, viz. lack of adequate design methodologies, lack of validation and verification support, maintenance problems. A decision table engineering workbench, that addresses these issues of decision table modeling and interfacing, is presented by means of a small but elaborate example.
THE KOLMOGOROV METRIC AND A GENERALIZATION ON A CLASSIFICATION OF CELLULAR AUTOMATA
Authors: D’ALOTTO LOUIS , GIARDINA CHARLES
Published: November 2004

This paper introduces and applies a new metric, on the space of bi-infinite strings (sequences), to the linear cellular automata classification approach of R. Gilman. The metric presented herein is a generalization of the metric used in the classification work of Gilman and it is shown that those original classification results also hold with this generalized metric.
EVOLVING CASCADE-CORRELATION NETWORKS FOR TIME-SERIES FORECASTING
Authors: McDonell John R. , Waagen Don E.
Published: November 2004

This investigation applies evolutionary search to the cascade-correlation learning network. Evolutionary search is used to find both the input weights and input connectivity of candidate hidden units. A time-series prediction example is used to demonstrate the capabilities of the proposed approach.
A FINELY-INTERLEAVED CONSISTENCY CHECKING METHOD FOR KNOWLEDGE-BASES
Authors: HARRISON JOHN V.
Published: November 2004

An efficient method to determine consistency in a knowledge-base is described. The traditional generation and evaluation steps are interleaved to compute the differences between two consecutive knowledge-base states. The method employs an optimized update propagation algorithm to improve efficiency. Updates to both the facts and the rule-base are supported by the method.
AN OBJECT-ORIENTED PROGRAMMING ENVIRONMENT FOR MULTIMEDIA COOPERATIVE INFORMATION SYSTEMS
Authors: POZZI SILVANO , GIACHINO LUCA
Published: November 2004

This paper illustrates an object-oriented programming environment, called Application Conference Interface (ACI), which has been designed in order to facilitate the implementation of cooperative information systems. It interfaces developers of cooperative applications with services provided by a software platform, called ImagineDesk. The platform offers a rich set of services which can be exploited by developers of cooperative applications in order to manage them, to exchange multimedia data and to control users' interactions according to their roles. Basically, the ACI provides a set of local abstractions of remote services. These abstractions take the form of local objects, hiding the details of the underlying physical network from the application developer. By exploiting the object-oriented paradigm, the ACI clearly confines the host environment and network constraints in few easily upgradable objects, thus resulting in a highly system-independent architecture.
RESPONSE — REQUIREMENTS SPECIFIC OBJECT MODEL FOR WORKGROUP COMPUTING
Authors: HAWRYSZKIEWYCZ IGOR , KARAGIANNIS DIMITRIS , MACIASZEK LESZEK , TEUFEL BERND
Published: November 2004

Assisted by the client-server architectures, power of contemporary workstations, and new multimedia, database and communication techniques, the workgroup computing (perhaps better known as CSCW — Computer-Supported Cooperative Work) is bound to change the way people in organizations collaborate to achieve common goals. New computer technologies change the way the cooperative work is conducted and they frequently lead to new practices that increase inter-personal productivity and business efficiency.

This article defines a conceptual and technological framework for a class of workgroup computing applications characterized by an asynchronous distributed interaction (different-time/different-place) during the development of shared artifacts. The proposed object model is called RESPONSE (REquirements SPecific Object Network System Environment). The model is "requirements specific" as it aims specifically at one, albeit dominant, class of workgroup applications. A particular workgroup application, chosen as representative of our model and used in examples, is the co-authoring of documents.

The proposed model determines functions and support required from hardware/ software platforms for workgroup computing. The object database component of such a platform is emphasized. A distributed management of versioned objects using four levels of workspaces is proposed. The model supports long transactions with persistent locks, checkout/checkin of versioned and unversioned objects, social and technical protocols to enhance the cooperation between users, etc. The workgroup interface for the RESPONSE model is also addressed.
COMBINING DEFAULT LOGIC DATABASES
Authors: BARAL CHITTA , KRAUS SARIT , MINKER JACK , SUBRAHMANIAN V. S.
Published: November 2004

During the past decade, it has become increasingly clear that the future generation of large-scale knowledge bases will consist, not of one single isolated knowledge base, but a multiplicity of specialized knowledge bases that contain knowledge about different domains of expertise. These knowledge bases will work cooperatively, pooling together their varied bodies of knowledge, so as to be able to solve complex problems that no single knowledge base, by itself, would have been able to address successfully. In any such situation, inconsistencies are bound to arise. In this paper, we address the question: "Suppose we have a set of knowledge bases, KB1, …, KBn, each of which uses default logic as the formalism for knowledge representation, and a set of integrity constraints IC. What knowledge base constitutes an acceptable combination of KB1, …, KBn?"
THE PRIME DECOMPOSITION OF KNOTTED PERIODIC ORBITS IN DYNAMICAL SYSTEMS
Authors: SULLIVAN MICHAEL C.
Published: November 2004

Templates are used to capture the knotting and linking patterns of periodic orbits of positive entropy flows in 3 dimensions. Here, we study the properties of various templates, especially whether or not there is a bound on the number of prime factors of the knot types of the periodic orbits. We will also see that determining whether two templates are different is highly nontrivial.
ON GENERALIZED UNKNOTTING OPERATIONS
Authors: NAKANISHI YASUTAKA
Published: November 2004

If a set of local moves can transform every knot into a trivial knot, it is called a generalized unknotting operation. The author collects generalized unknotting operations and classify them up to local equivalence.
KNOTTING OF REGULAR POLYGONS IN 3-SPACE
Authors: MILLETT KENNETH C.
Published: November 2004

The probability that a linear embedding of a regular polygon in R3 is knotted should increase as a function of the number of sides. This assertion is investigated by means of an exploration of the compact variety of based oriented linear maps of regular polygons into R3. Asymptotically, an estimation of the probability of knotting is made by means of the HOMFLY polynomial.
UNSPLITTABILITY OF RANDOM LINKS
Authors: DIAO YUANAN
Published: November 2004

Random linking problems arise in physical situations when there is more than one circular molecule present in a fixed volume, and linking of these molecules becomes possible. Mathematically, this is the linking problem for two or more randomly generated polygons. In this paper, we study the asymptotic case when the number of random polygons of fixed length in a fixed volume tends to infinity, and prove that under certain conditions that the probability that these random polygons form an unsplittable link tends to one.
THE RESHETIKHIN-TURAEV REPRESENTATION OF THE MAPPING CLASS GROUP
Authors: WRIGHT GRETCHEN
Published: November 2004

The Reshetikhin-Turaev representation of the mapping class group of an orientable surface is computed explicitly in the case r = 4. It is then shown that the restriction of this representation to the Torelli group is equal to the sum of the Birman-Craggs homomorphisms. The proof makes use of an explicit correspondence between the basis vectors of the representation space, and the Z/2Z-quadratic forms on the first homology of the surface. This result corresponds to the fact, shown by Kirby and Melvin, that the three-manifold invariant when r = 4 is related to spin structures on the associated four-manifold.
THE VMI-MODEL REVISITED IN THE ODD-ODD RARE-EARTH NUCLEI
Authors: JAIN A.K. , GOEL ALPANA
Published: November 2004

A rather complete formulation of the variable moment of inertia model is presented for odd-odd nuclei and relationship obtained between the energy ratios and the parameters of the model. Range of validity of the model is defined and Mallmann-like curves are obtained for the odd-odd nuclei. An application is made to the rare-earth region and results are presented for the K+=(Ωp+Ωn) bands and those K−=|Ωp−Ωn| bands which remain reasonably free from Coriolis mixing. The parameters obtained from the fitting show excellent agreement with the predictions of the model. An interesting correlation between the variation of the moment of inertia of the odd-odd rotational bands with those of the neighboring odd-A nuclei involving either the same neutron or same proton configuration is also presented.
NEUTRON MATTER – QUARK MATTER PHASE TRANSITION AND QUARK STAR
Authors: MISHRA H. , MISRA S.P. , PANDA P.K. , PARIDA B.K.
Published: November 2004

We consider the neutron matter and quark matter phase transition along with possible existence of hybrid quark stars. The equation of state for neutron matter is obtained using a nonperturbative method with pion dressing of the neutron matter and an analysis similar to that of symmetric nuclear matter. The quark matter sector is treated perturbatively in the small distance domain. For bag constant B1/4=148 MeV , a first order phase transition is seen. In the context of neutron quark hybrid stars, Tolman-Oppenheimer-Volkoff equations are solved using the equations of state for quark matter and for neutron matter with a phase transition as noted earlier. Stable solutions for such stars are obtained with the Chandrasekhar limit as 1.58 Mʘ and radius around 10 km. The bulk of the star is quark matter with a thin crust of neutron matter of less than a kilometer.
DYNAMICAL CALCULATION OF CENTRAL ENERGY DENSITIES IN RELATIVISTIC HEAVY-ION COLLISIONS
Authors: DEAN D.J. , UMAR A.S. , STRAYER M.R.
Published: November 2004

The 3+1 dimensional string-parton model is used to calculate energy densities and temperatures of produced mesons during relativistic heavy-ion collisions. We compare maximum energy densities with the experimental estimates obtained from the Bjørken formula. Although the string-parton model reproduces transverse energy distributions, dET/dη, the dynamical energy densities of the produced mesons are three to four times smaller than estimates based on the Bjørken formula with a formation time of 1 fm/c. We discuss various time scales which contribute to this discrepancy and suggest a modified interpretation of the Bjørken formula.
NEUTRINO EMISSIVITY OF NONEQUILIBRIUM QUARK STAR MATTER
Authors: SAHU PRADIP
Published: November 2004

The exact neutrino emissivity of quark star matter has been calculated numerically without invoking beta equilibrium condition. Such a condition can prevail in quark star matter undergoing rapid compression. We derive the neutrino emissivity formula from the direct beta processes and calculate the neutrino emissivity numerically by considering the difference in the chemical potentials of u, d (s) quarks and e electron, (δμ=μd(s)− μu−μe) for the two- and three-flavor quark matter. We find that the emissivity increases (decreases) with increase in δμ (−δμ) which is quite different from that of the equilibrium (δμ=0) emissivity. Moreover, it has been observed that the exponent in the temperature and the baryon density of the emissivity is very sensitive to δμ.
CHARACTERISTIC FEATURES AND MECHANISMS OF NUCLEAR FRAGMENTATION
Authors: RICHERT J.
Published: November 2004

Nuclear fragmentation at high energy shows characteristic features which may serve as a guideline for the description and understanding of the mechanisms leading to experimentally observed mass or charge distributions. Results obtained by means of different models proposed in the past are analysed and discussed. Using the available information, recent efforts made in order to find the clue of the mechanisms which lead to the disassembly of nuclei are presented.
SLOW TARGET-ASSOCIATED PARTICLE PRODUCTION IN 6Li-Em COLLISIONS AT 4.5 A GeV/c
Authors: SHERIF M.M. , HEGAB M.K. , ABDELSALAM A. , EL-SHARKAWY S.A. , TAWFIK A.M.
Published: November 2004

The multiplicity and angular distributions of charged particles with velocities smaller than 0.7c produces in 6 Li-Em collisions at 4.5 A GeV/c. The multiplicity distribution is independent of the energy of the projectile or its mass. The Ng multiplicity distributions are fitted with a parameter free model whose input information is the Ng multiplicity distribution produced in proton induced reactions.
ON THE PREFORMATION FACTORS IN ALPHA DECAY
Authors: LUDU A. , GREINER W. , SANDULESCU A.
Published: November 2004

Alpha decay is described as a new large amplitude collective motion in nuclei. The total energy is evaluated in the frame of the nonlinear hydrodynamics approach which leads to the formation of solitons on the nuclear surface. A new minimum appears in the total energy due to the shell effects for 208 Pb and 4 He introduced phenomenologically. The minimum was chosen to be degenerate with the ground state minimum. Consequently a new coexistence model consisting of the usual shell model and an alpha particle cluster-like model describing a soliton moving on the nuclear surface is obtained. The corresponding amplitudes describe excellently the experimental preformation factors for alpha decay of Po isotopes.
RELATIVISTIC Ω−-HYPERON ATOM
Authors: GIANNINI M.M. , KRIVORUCHENKO M.I.
Published: November 2004

The X-ray transitions of the Ω−-hyperons captured to the atomic orbits of heavy nuclei can be used to measure with high precision the mass, magnetic and quadrupole moments of the Ω−-hyperon. In the presence of accurate measurements, a careful treatment of the relativistic effects beyond the lowest order ones described by the Fermi-Breit potential is required. We consider a relativistic wave equation for the bound states of the Ω−-hyperon in the Coulomb static potential taking into account the magnetic, quadrupole and octupole moments of the Ω−-hyperon. The kinematic constraints are imposed to the Rarita-Schwinger spinors using Lagrange’s multipliers. These constraints are equivalent to the requirement that timelike and spacelike spin-1/2 components of the Rarita-Schwinger spinors be zero in the comoving particle frame. We perform a reduction of this equation to eight coupled equations for the radial wave functions which can be used for numerical estimates of the relativistic effects beyond (v/c)2.
Symmetry and the Origin of Nuclear Deformation
Authors: GUIDRY MIKE , WU CHENG-LI
Published: November 2004

Evidence is presented that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that abnormal-parity orbitals play important but sec ondary roles in the microscopic origin of deformation. This contradicts many common ideas concerning deformation, but is in accord with the point of view underlying the Fermion Dynamical Symmetry Model. We argue that the deformation systematics of the FDSM and the Nilsson model are mutually consistent, and that in the FDSM the n−p quadrupole residual interaction is responsible for deformation. The same principles applied to superdeformation indicate that abnormal parity orbitals have a much more direct influence on superdeformation than on normal deformation.
WHY ARE SOME NUCLEI SPHERICAL?
Authors: KUMAR KRISHNA
Published: November 2004

Energy minimization is not sufficient to determine whether a nucleus is spherical or deformed. The quantal zero-point motion can make a nucleus spherical even if the potential energy has a deformed minimum. However, some general conditions give deformed shape as the natural state of atomic nuclei. They are spherical only under some special conditions. Some general criteria for distinguishing spherical nuclei from deformed, as well as some advantages of using a deformed-shell model rather than a spherical-shell model, are presented.
What are unphysical (or spurious) states in a collective boson subspace?
Authors: Takada K.
Published: November 2004

Difference between the meanings of unphysical states in the boson mapping for the whole fermion space and collective fermion subspace is discussed.
ERRATA: THE VMI-MODEL REVISITED IN THE ODD-ODD RARE-EARTH NUCLEI
Authors: JAIN A. K. , GOEL ALPANA
Published: November 2004

A rather complete formulation of the variable moment of inertia model is presented for odd-odd nuclei and relationship obtained between the energy ratios and the parameters of the model. Range of validity of the model is defined and Mallmann-like curves are obtained for the odd-odd nuclei. An application is made to the rare-earth region and results are presented for the K+=(Ωp+Ωn) bands and those K−=|Ωp−Ωn| bands which remain reasonably free from Coriolis mixing. The parameters obtained from the fitting show excellent agreement with the predictions of the model. An interesting correlation between the variation of the moment of inertia of the odd-odd rotational bands with those of the neighboring odd-A nuclei involving either the same neutron or same proton configuration is also presented.
AN AGE-DEPENDENT TWO-SEX POPULATION GROWTH
Authors: BOUZINAB A. , ARINO O.
Published: November 2004

In this paper, we deal with equations for a two-sex population growth with age-dependence. We assume that births are produced by random interactions between males and females. The model yields a coupled system of two variables. Global existence and uniqueness are proved. The existence of solutions growing exponentially is shown. Finally, the asymptotic behavior of the solution is investigated (in a particular case).
AN INTRODUCTION TO GENERAL EVOLUTION THEORY
Authors: LASZLO ERVIN
Published: November 2004

The study of evolution extends beyond any given scientific discipline, to embrace the sequential but nonlinear evolution of complex systems in the cosmos and in the biosphere. The exploration of a truly general theory of evolution has major consequences for our understanding of physical, biological and human-social phenomena. New developments in various scientific fields, most notably in the systems sciences, provide the basis for the investigation of the cross-disciplinary laws and regularities that furnish the premises of general evolution theory.
RECONSTRUCTION AND LABELING OF CORONARY NETWORKS FROM BIPLANE ANGIOGRAPHY: VALIDATION ON REAL DATA
Authors: GARREAU M. , COATRIEUX J.L. , WINDYGA P. , ROUGEE A.
Published: November 2004

A new method aimed at the three-dimensional reconstruction and the labeling of cardiac vascular networks has been already reported. Two X-ray views are used in conjunction with a qualitative symbolic model of the arterial tree. This short paper summarizes the main steps of the overall approach and describes the first results obtained on real data. The most critical issues are then emphasized and discussed.
NEURAL NETWORKS TO COMPUTE MOLECULAR DYNAMICS
Authors: LIEBOVITCH LARRY S. , ARNOLD NIKITA D. , SELECTOR LEV Y.
Published: November 2004

Large molecules such as proteins have many of the properties of neural networks. Hence, neural networks may serve as a natural and thus efficient method to compute the time dependent changes of the structure in large molecules. We describe how to encode the spatial conformation and energy structure of a molecule in a neural network. The dynamics of the molecule can then be computed from the dynamics of the corresponding neural network. As a detailed example, we formulated a Hopfield network to compute the molecular dynamics of a small molecule, cyclohexane. We used this network to determine the distribution of times spent in the twist and chair conformational states as the cyclohexane thermally switches between these two states.