bluuebunny/crossref_metadata_2025 huggingface dataset:
LIMITING THE MASSES AND COUPLING STRENGTHS OF THE SECOND Z BOSON
Authors: CHHABRA T. , RAM BABU P.
Published: November 2004

We relate the observables of [Formula: see text] scatterings, e+e−→μ+μ− and [Formula: see text] to look for the existence of new neutrinos coupling to the second Z boson. The observables in νe scattering and [Formula: see text] are sensitive to the presence of new neutrinos, and the ones in e+e−→μ+μ− are sensitive to additional Z bosons. Hence the relations between low energy observables of these reactions can be used to test the existence of new neutrinos coupling to the standard Z boson and/or the second Z boson. From available experimental data, the mass and coupling strengths of the second Z boson are constrained in a model-independent way.
NEUTRINO MASSES IN A GRASSMANNIAN SU(5) MODEL
Authors: DELBOURGO R. , ROLEDA R.
Published: November 2004

The gauge interaction and mass generation through the Higgs mechanism is worked out for a Grassmannian SU(5) model, which among many other states, predicts three light neutrinos and two heavy ones. It is found that Simpson’s 17 keV neutrino remains incompatible with the MSW solution to the solar neutrino puzzle in this framework
INTEGRABLE FIELD THEORY OF THE q-STATE POTTS MODEL WITH 0<q<4
Authors: CHIM LEUNG , ZAMOLODCHIKOV ALEXANDER
Published: November 2004

Two-dimensional quantum field theory obtained by perturbing the q-state Potts-model CFT (0<q<4) with the energy-density operator Φ(2, 1) is shown to be integrable. The particle content of this QFT is conjectured and the factorizable S matrix is proposed. The limit q→1 is related to the isotropic-percolation problem in 2D and so we make a few predictions about the size distributions of the percolating clusters in the scaling domain.
NOVEL FACETS OF THE NONABELIAN ANOMALY
Authors: CHANG LAY NAM , LIANG YIGAO
Published: November 2004

We derive new constraints on multipoint amplitudes involving chiral currents. These constraints are valid for arbitrary values of the momenta of the currents, and for arbitrary chiral symmetry-breaking schemes. Examples of how these constraints are realized for several symmetry-breaking patterns are given, and relations to the Wess—Zumino action are discussed. The constraints are shown to result from the presence of nonAbelian phases on surfaces in gauge group parameter space. They represent subtler manifestations of a general class of topological structures, the simplest of which gives rise to the nonAbelian anomaly equation by the Abelian phase winding.
κ SYMMETRY AS WORLD SHEET SUPERSYMMETRY IN D=10 HETEROTIC SUPERSTRING
Authors: TONIN M.
Published: November 2004

We extend a recent formulation of the D=10, GS heterotic string with (2, 0) world sheet supersymmetry involving pure spinors. The new model exhibits an (8, 0) world sheet supersymmetry which can be interpreted as κ symmetry in disguise.
PLANAR AND LIGHT-CONE GAUGES WITH A CAUSAL SINGLE-POLE PRESCRIPTION
Authors: BURNEL A. , CAPRASSE H.
Published: November 2004

The gluon-exchange contribution to the gluon self-energy is computed in the planar and light-cone gauges with the unique single-pole causal prescription. In both cases the result does not satisfy the Ward identity. This could be related to the difference between the numbers of degrees of freedom in configuration and momentum spaces and points out a violation of unitarity in true axial gauges.
THE CALCULATION OF THE ELECTROMAGNETIC π+−π0 MASS DIFFERENCE WITHIN QCD
Authors: PIVOVAROV A.A.
Published: November 2004

The electromagnetic π+−π0 mass difference is calculated with QCD sum rules technique in the chiral limit. The obtained result Δmπ=4.4±1.1 MeV is in reasonable agreement with the experimental value (Δmπ)exp=4.43±0.03 MeV. The developed technique can be also applied to the determination of the electromagnetic mass difference of K mesons.
PION-CLOUD EFFECTS ON THE ELECTROMAGNETIC PROPERTIES OF NUCLEONS IN A QUARK MODEL
Authors: BARIK N. , JENA S.N. , RATH D.P.
Published: November 2004

Incorporating corrections for the center-of-mass motion and pion-cloud effects the nucleon electromagnetic form factors [Formula: see text] are computed in an independent quark model based on the Dirac equation with a confining potential [Formula: see text] The static quantities like magnetic moment μN, charge radius [Formula: see text] and axial vector coupling constant (gA)n→peν of the nucleons computed in this model are in reasonable agreement with the experiment. The pseudoscalar and the pseudovector pion-nucleon coupling constants are obtained as gNNπ=13.52 and fNNπ=0.284, which are in excellent agreement with the experimental data.
SEMICLASSICAL APPROACH TO FINITE-N MATRIX MODELS
Authors: LECHTENFELD OLAF
Published: November 2004

We reformulate the zero-dimensional Hermitian one-matrix model as a (nonlocal) collective field theory, for finite N. The Jacobian arising as a result of changing variables from matrix eigenvalues to their density distribution is treated exactly. The semiclassical loop expansion turns out not to coincide with the (topological) [Formula: see text] expansion, because the classical background has a nontrivial N dependence. We derive a simple integral equation for the classical eigenvalue density, which displays strong nonperturbative behavior around N=∞. This leads to IR singularities in the large-N expansion, but UV divergencies appear as well, despite remarkable cancelations among the Feynman diagrams. We evaluate the free energy at the two-loop level and discuss its regularization. A simple example serves to illustrate the problems and admits explicit comparison with orthogonal-polynomial results.
CHIRAL PERTURBATION THEORY AT THE QUARK LEVEL
Authors: IVANOV A.N. , NAGY M. , TROITSKAYA N.I.
Published: November 2004

The chiral perturbation theory is developed at the quark level within the extended Nambu-Jona-Lasinio model, which we used for the low-energy approximation of QCD in the leading order of the large N expansion. In terms of constituent-quark loop diagrams we analyze all of the main low-energy effects caused by the first order corrections in the current-quark-mass expansions. For the correct description of the η→3π decays we confirm the important role of the final-state interaction quoted by Gasser and Leutwyler.
CORRELATION FUNCTIONS IN NONCRITICAL (SUPER) STRING THEORY
Authors: ABDALLA E. , ABDALLA M.C.B. , DALMAZI D. , HARADA KOJI
Published: November 2004

We consider the correlation functions of the tachyon vertex operator of the super Liouville theory coupled to matter fields in the super Coulomb gas formulation, on world sheets with spherical topology. After integrating over the zero mode and assuming that the s parameter takes an integer value, we subsequently continue it to an arbitrary real number and compute the correlators in a closed form. We also included an arbitrary number of screening charges and, as a result, after renormalizing them, as well as the external legs and the cosmological constant, the form of the final amplitudes do not modify. The result is remarkably parallel to the bosonic case. For completeness, we discussed the calculation of bosonic correlators including arbitrary screening charges.
ALGEBRAIC STUDY ON THE POISSON STRUCTURE OF LAX OPERATOR OF B AND C TYPE AND SUPER LAX OPERATOR.
Authors: IKEDA KAORU
Published: November 2004

The Poisson structure of Lax operator of B and C type and super Lax operator which has odd parity are studied. The algebraic structure of Poisson structure as a background of Lax equation is thrown light on.
DECOMPOSITION OF SYMMETRIC AND EXTERIOR POWERS OF THE ADJOINT REPRESENTATION OF ${\mathfrak g}l_N$ 1: UNIMODALITY OF PRINCIPAL SPECIALIZATION OF THE INTERNAL PRODUCT OF THE SCHUR FUNCTIONS
Authors: KIRILLOV ANATOL N.
Published: November 2004

The problem of decomposing the symmetric and exterior algebras of the adjoint representation of the Lie algebra [Formula: see text] into [Formula: see text]-irreducible components are considered. The exact formula for the principal specialization of the internal product of the Schur functions (similar to the formula for Kostka-Foulkes polynomials) is obtained by the purely combinatorial approach, based on the theory of rigged configurations. The stable behaviour of some polynomials is studied. Different examples are presented.
SELECTED TOPICS IN QUANTUM GROUPS
Authors: SOIBELMAN YAN S.
Published: November 2004

Some recent results in the representation theory of the algebras of functions on compact quantum groups are presented. Applications to different subjects are given.
FROM GENERAL ZAKHAROV-SHABAT EQUATIONS TO THE KP AND THE TODA LATTICE HIERARCHIES
Authors: TAKEBE Takashi
Published: November 2004

The general Zakharov-Shabat type equations without the L operators are shown to be equivalent to the KP and the Toda lattice hierarchies. That is, the Zakharov-Shabat type equations automatically guarantee the existence of the L operators.
DKRL — AN OBJECT-ORIENTED LANGUAGE TO SUPPORT PROBLEM SOLVING IN DISTRIBUTED BLACKBOARD SYSTEMS
Authors: SAXENA MANOJ K. , BISWAS K.K. , BHATT P.C.P.
Published: November 2004

For distributed problem solving systems, there is a need to define knowledge at two levels, one external to the agents and the other internal to the agents. External knowledge is required to achieve cooperation among agents and global convergence of the problem solving process, whereas internal knowledge is required to solve the sub-problems assigned to the agents. External knowledge specifies the role of each agent and its relationship with other agents in the system. Internal knowledge specifies knowledge structure and the problem solving process within each agent.

DKRL is an object-oriented language for describing distributed blackboard systems. In DKRL a problem solving system is described as a collection of distributed intelligent, autonomous agents (modelled as objects), cooperating to solve the problem. An agent consists of a knowledge base, a behaviour part, a local controller, a monitor, and a communication controller. DKRL has characteristics of a dynamic nature, i.e. the agents can be created dynamically and the relationship among them also changes dynamically. An agent in DKRL’s computational model cannot be activated by more than one message at the same time and uses a virtual synchrony environment for message transmission among agents. This model combines the advantages of remote procedure calls with those of asynchronous message passing. DKRL allows object-oriented programming techniques to be used for system development and facilitates the development by allowing one-to-one mapping between the objects in the knowledge model and the knowledge base of the agent.

In this paper, we give an overview of the distributed blackboard paradigm for which DKRL was developed as well as the design considerations. We also propose and formally describe the underlying models of DKRL and explain how concurrency is exploited by DKRL. We conclude with the current status of and preliminary experience with DKRL in using it for the development of a gate assignment problem.
BLACKBOARD CONCEPTS FOR DATA FUSION APPLICATIONS
Authors: LLINAS J. , ANTONY RICHARD T.
Published: November 2004

Data fusion has been defined as a process dealing with the association, correlation, and combination of data and information from multiple sources to achieve refined position and identity estimates for entities, and complete and timely assessments of related situations and threats, and their significance. This process (sometimes labeled a “technology”) is pervasive, i.e. capable of broad, multi-domain application. Indeed, data fusion has found extensive application in the commercial/industrial sector as well, in areas such as robotics and process control, and for numerous applications requiring intelligent, autonomous processes and capabilities. One of the purposes of this paper is to describe the evolving standard description of the data fusion process ascribed to by the U.S. Joint Directors of Laboratories (JDL) Data Fusion Subpanel (a Department of Defense organization), as well as components of the attendant lexicon and taxonomy.

While the specific definitions of a “situation assessment (SA)” and a “threat assessment (TA)” have proven to be problem-dependent for most defense applications, these notions generally encompass a large quantity of knowledge which reflect the (dynamic) constituency-dependency relationships among objects of various classes as well as events and activities of interest. Formulation of hypotheses about situations and threats is a process having the following properties:

• it employs many types of knowledge

• it must consider multiple, asynchronous activities

• multiple types of dynamic and static data must be processed

• numerous sub-networks of interest in the situation/threat picture (numerous constituency-dependency relationships) exist—this leads to feedforward/backward inferencing requirements

• information-processing strategies are required to produce estimates of aggregated force structures (given individual unit positions and identities), as well as aggregated behaviors (given individual events or activities)

• the situational or threat state is often ephemeral and thus temporal reasoning capabilities must be part of the process

The paper expands on the processes and techniques involved in SA and TA analysis, and describes, from various points of view, why the blackboard paradigm is properly applicable to problems of SA and TA analysis. This assessment includes various trade-off factors (features, benefits, and disadvantages or complexities) in applying blackboard concepts to data fusion related reasoning processes.

Specific research and development by the authors and synthesis of the results of a survey on data fusion applications (shown within) has led to the formulation of a recommended generic, ideal blackboard architecture for these defense problems described in the paper.
BUILDING MODELS FOR QUALITATIVE PREDICTION OF SYSTEM DYNAMIC BEHAVIOR
Authors: LEE SUKHAN , CHEN JUDY
Published: November 2004

This paper presents a method of automatically constructing a model or a set of constraints from domain principles for solving the dynamic behavior of a mechanical system through qualitative simulation. It emphasizes the following issues: the extraction of a set of necessary and sufficient constraints which provides the minimum uncertainty associated with qualitative simulation, from the fundamental principles and laws of physics based solely on the physical description of a given mechanical system; and the modification of constraints through time by detecting and identifying “system discontinuities” due to collisions, separations, and other critical states associated with each of the object primitives.

The first is accomplished by describing a mechanical system by a collection of object and inter-connection primitives, which allows direct instantiating of all the relevant physics laws from the knowledge base. Then, the final set of constraints having the minimum complexity and uncertainty is extracted from the relevant physics laws, based on an A* algorithm with heuristics providing the problem solving expertise. The second is accomplished by monitoring whether the states of any individual sub-systems evolve to system discontinuities represented by intra/inter subsystem critical states.
RECENT RESULTS IN HIERARCHICAL CLUSTERING: I–THE REDUCIBLE NEIGHBORHOODS CLUSTERING ALGORITHM
Authors: BRUYNOOGHE MICHEL
Published: November 2004

The clustering of large data sets is of great interest in fields such as pattern recognition, numerical taxonomy, image or speech processing.

The traditional Ascendant Hierarchical Algorithm (AHC) cannot be run for sets of more than a few thousand elements.

The reducible neighborhoods clustering algorithm, which is presented in this paper, has overtaken the limits of the traditional hierarchical clustering algorithm by generating an exact hierarchy on a large data set. The theoretical justification of this algorithm is the so-called Bruynooghe reducibility principle, that lays down the condition under which the exact hierarchy may be constructed locally, by carrying out aggregations in restricted regions of the representation space.

As for the Day and Edelsbrunner algorithm, the maximum theoretical time complexity of the reducible neighborhoods clustering algorithm is O(n2 log n), regardless of the chosen clustering strategy. But the reducible neighborhoods clustering algorithm uses the original data table and its practical performances are by far better than Day and Edelsbrunner’s algorithm, thus allowing the hierarchical clustering of large data sets, i.e. composed of more than 10 000 objects.
INTEGRATED SEGMENTATION AND RECOGNITION THROUGH EXHAUSTIVE SCANS OR LEARNED SACCADIC JUMPS
Authors: MARTIN GALE L. , RASHID MOSFEQ , PITTMAN JAMES A.
Published: November 2004

This paper advances two approaches to integrating handwritten character segmentation and recognition within one system, where the underlying function is learned by a backpropagation neural network. Integrated segmentation and recognition is necessary when characters overlap or touch, or when an individual character is broken up. The first approach exhaustively scans a field of characters, effectively creating a possible segmentation at each scan point. A neural net is trained to both identify when its input window is centered over a character, and if it is, to classify the character. This approach is similar to most recently advanced approaches to integrating segmentation and recognition, and has the common flaw of generating too many possible segmentations to be truly efficient. The second approach overcomes this weakness without reducing accuracy by training a neural network to mimic the ballistic and corrective saccades (eye movements) of human vision. A single neural net learns to jump from character to character, making corrective jumps when necessary, and to classify the centered character when properly fixated. The significant aspect of this system is that the neural net learns to both control what is in its input window as well as to recognize what is in the window. High accuracy results are reported for a standard database of handprinted digits for both approaches.
ADAPTIVE CLASSIFICATION BY NEURAL NET BASED PROTOTYPE POPULATIONS
Authors: PELEG KALMAN , BEN-HANAN URI
Published: November 2004

We have developed an algorithm for unsupervised adaptive classification based on a finite number of “prototype populations” with distinctly different feature distributions, each representing a typically different source population of the inspected products. Intermittently updated feature distributions, of samples collected from the currently classified products, are compared to the distributions of pre-stored prototype populations, and accordingly the system switches to the most appropriate classifier. The goal of our approach is similar to the objectives of the previously proposed “Decision Directed” adaptive classification algorithms but our solution is particularly suitable for automatic inspection and classification on a production line, when the inspected items may come from a finite number of distinctly different sources.

The recognition of prototype populations as well as the classification task proper may be implemented by conventional classifiers, however neural networks (NN) are advantageous in two respects: There is no need to develop separate mathematical models for each classifier because the NN does it automatically during the training stage. The parallel structure of NN has the potential for very fast classification in real time, if implemented by dedicated parallel hardware. This is particularly important for high speed automatic sorting on a production line.

The practical feasibility of the approach was demonstrated by two applied examples, wherein two prototype populations of apples are recognized and sorted by size and color derived by machine vision. Three “Boltzmann-Perceptron Networks” (BPN) were used, one to recognize the prototype populations, while switching between the other two, for optimally classifying apples into two size and color categories. It is shown that misclassifications by adaptive classification are reduced, in comparison to non-adaptive classification.
A NEW THINNING ALGORITHM BASED ON CONTROLLED DELETION OF EDGE REGIONS
Authors: DIMAURO G. , IMPEDOVO S. , PIRLO G.
Published: November 2004

In this paper a new thinning algorithm for binary patterns is presented. The algorithm is based on an iterative controlled removal procedure working on entire regions of the pattern. The thinning process permits to obtain skeletons retaining important specificities of the pattern useful for robust structural descriptions. The experimental results carried out on typewritten and handwritten characters point out the efficacy of the algorithm with respect to other techniques in literature.
INVARIANT THINNING
Authors: ECKHARDT ULRICH , MADERLECHNER GERD
Published: November 2004

One of the most widely used methods for preprocessing binary images is thinning. The popularity of this method rests on the fact that considerable data reduction is achieved while retaining “essential” properties of the original image. Moreover, topological features, which cannot be verified by a genuinely parallel method (by Minsky and Papert22) are more easily treated in thinned images. For these reasons, many articles on this topic were published in the literature. Most of them are concerned with modifications of existing methods in order to yield “nicer” results out of the thinning process. Also, many results of numerical experiments are available in different publications.

The aim of this paper is to show that the quite natural requirement of invariance of the results obtained by thinning leads nearly automatically to a method proposed by the authors in different publications. Moreover, this method is genuinely parallel and well-defined so that it is possible to investigate it theoretically.

The practical feasibility of the method is also discussed.
ANALYTICAL COMPARISON OF THINNING ALGORITHMS
Authors: ZHANG Y.Y. , WANG P.S.P.
Published: November 2004

This paper deals with analyzing and comparing several key thinning algorithms in terms of various different methodologies. From these analyses and comparisons, a new sequential model thinning algorithm using heuristic, hybrid methods is presented. It intends to produce, based on past experience, thinned skeletons of thickness one from input patterns, keep connectivity, and eliminate unnecessary pixels. Several illustrative examples on various patterns were tested and the results compared. The parallel model thinning algorithm is still open.
STRANGE ATTRACTORS AND DYNAMICAL MODELS
Authors: SHIL'NIKOV L. P.
Published: November 2004

Three main types of strange attractors are described; namely hyperbolic, Lorenz-type and quasiattractors. In addition, a recent family of quasiattractors originating from Chua's circuit is briefly described. In connection with the strange attractors, we stress that models having quasiattractors containing structurally unstable homoclinic Poincaré orbits are "bad", in the sense of Ref. 24.
BISPECTRAL ANALYSIS OF CHUA'S CIRCUIT
Authors: ELGAR STEVE , KENNEDY MICHAEL PETER
Published: November 2004

Bispectral analysis (which isolates quadratic nonlinear interactions among triads of Fourier components) is used to investigate bifurcations in Chua's circuit. For period-doubled limit cycles, the dominant interactions of the circuit are quadratically nonlinear, and bicoherence spectra isolate the phase coupling between increasing numbers of triads of Fourier components as the nonlinearity of the system is increased. For circuit parameters that result in a chaotic, Rössler-type attractor, bicoherence spectra indicate that quadratic nonlinear interactions are important to the dynamics. For parameters that lead to the double scroll chaotic attractor the bispectrum is zero, suggesting that nonlinear interactions of order higher than quadratic dominate the dynamics. Higher-than-second order spectra (e.g. trispectra) are required to isolate the individual nonlinear interactions for the double scroll.
RECONSTRUCTING THE DYNAMICS OF CHUA'S CIRCUIT
Authors: GLOVER JAMES , MEES ALISTAIR
Published: November 2004

The Chua circuit can be treated as a black box giving output which can be studied in a number of ways. This allows us to test some novel nonlinear system modeling methods. In particular, we show how to locate important dynamical features such as fixed points and near-heteroclinic cycles with very little effort, and then how to build a more detailed dynamical model to verify these discoveries.
A NEW TYPE OF STRANGE ATTRACTOR RELATED TO THE CHUA'S CIRCUIT
Authors: BELYKH V. N. , CHUA L. O.
Published: November 2004

We present a new type of strange attractors generated by an odd-symmetric three-dimensional vector field with a saddle-focus having two homoclinic orbits at the origin. This type of attractor is intimately related to the double-scroll Chua's attractor. We present the mathematical properties which proved rigorously the chaotic nature of this strange attractor to be different from that of a Lorenz-type attractor or a quasi-attractor.

In particular, we proved that for certain nonempty intervals of parameters, our two-dimensional map has a strange attractor with no stable orbits. Unlike other known attractors, this strange attractor contains not only a Cantor set structure of hyperbolic points typical of horseshoe maps, but also there exist unstable points (i.e. stable in reverse time) belonging to the attractor as well. This implies that the points from the stable manifolds of the hyperbolic points must necessarily attract the unstable points.
STOCHASTIC RESONANCE IN THE NONAUTONOMOUS CHUA'S CIRCUIT
Authors: ANISHCHENKO V. S. , SAFONOVA M. A. , CHUA L. O.
Published: November 2004

The dynamics of the nonautonomous Chua's circuit driven by a sinusoidal signal and additive noise is investigated numerically via the "two-state" dynamics method. The possibility of realizing the phenomenon of stochastic resonance (SR) is established. The SR is characterized by an increase in the signal-to-noise ratio (SNR) due to the coherent interaction between the characteristic frequencies of the chaotic bistable Chua's circuit and the modulation frequency of the input. The SNR can be controlled by both external noise and system parameter variations in this circuit. The statistical characteristics of the "chaos-chaos" type intermittency and their correlation with the optimal conditions for SR are investigated.
HIGH-FREQUENCY OSCILLATIONS FROM CHUA'S CIRCUIT
Authors: LUKIN K. A.
Published: November 2004

The preliminary results of experimental investigations of chaotic oscillations from Chua's circuit at high frequencies are reported. The double-scroll Chua's attractor with the usual set of LC-circuit parameters was observed at 100 KHz. A new region in the parameter space of Chua's circuit was discovered where the double-scroll Chua's attractor exists which allows an increase in the working frequency of up to 300 KHz. The highest central frequency f = 7.65 MHz of a chaotic oscillation was obtained for the case of Chua's circuit with a one-mode coaxial resonator. The ergodic torus and resonant tori with different rational Poincaré rotation numbers are observed. The possibility for obtaining from Chua's circuit the spread spectrum chaotic signals was shown.
INCORPORATING OBJECT-ORIENTED CONCEPTS TO CIRCUIT SIMULATION
Authors: LOH WAI LUNG
Published: November 2004

In this paper we describe the use of object-oriented techniques in circuit simulation. Object-oriented approaches to VLSI modeling have been proposed several times as the solution to the growing problem of complexity in hardware description systems.

Our approach is to evaluate the requirements of circuit simulation, based on object-oriented techniques, and define an abstract model that addresses these sets of requirements adequately. The model is centred on three simulation methods, which we propose specifically for combinational and sequential circuit simulation. Next, we propose a set of recommendations, which are viewed as informal transformation rules, for mapping the abstract model to its concrete form. The procedure is a simple one-to-one mapping. We also provide a standard mechanism for interconnecting objects at different levels of simulation.
A REAL-FREQUENCY APPROACH TO THE DESIGN OF A LOW-PASS HIGH-PASS REACTANCE-LADDER DIPLEXER
Authors: ZHU YI-SHENG , CHEN WAI-KAI
Published: November 2004

A real-frequency approach to the design of a diplexer having Butterworth or elliptic response is presented. The real parts of two minimum reactance functions are preassigned from the given transducer power gains. Their imaginary parts are derived by means of the rational Hilbert transform. Using a formula relating the derivative of a variable xk in an unknown vector X with respect to an entry in the coefficient matrix of a system of linear equations AX = B introduced in the appendix, the least pth method is adopted to implement the solution process, greatly reducing the highly nonlinear combination between the objective functions and the independent variables and resulting in a successful design of a diplexer approximating the Butterworth or elliptic response, both in the low-pass and the high-pass channels.
A SEARCH SPACE PRUNING METHOD FOR TEST PATTERN GENERATION USING SEARCH STATE DOMINANCE
Authors: FUJINO TAKAYUKI , FUJIWARA HIDEO
Published: November 2004

In this paper, we present a new technique that can prune search space in test-pattern generation for combinational circuits. We extend the concept of search state equivalence derived by Giraldi and Bushnell, to that of search state dominance, and propose a new extended method, DST (Dominant STate hashing) algorithm, based on the search state dominance. The DST algorithm can prune the search space more effectively than the EST (Equivalent STate hashing) algorithm of Giraldi and Bushnell. Experimental results on benchmark circuits are reported.
BIFURCATIONS AND CHAOS IN A PERIODIC PREDATOR-PREY MODEL
Authors: KUZNETSOV YU.A. , MURATORI S. , RINALDI S.
Published: November 2004

The model most often used by ecologists to describe interactions between predator and prey populations is analyzed in this paper with reference to the case of periodically varying parameters. A complete bifurcation diagram for periodic solutions of period one and two is obtained by means of a continuation technique. The results perfectly agree with the local theory of periodically forced Hopf bifurcation. The two classical routes to chaos, i.e., cascade of period doublings and torus destruction, are numerically detected.
IS SENSITIVE DEPENDENCE ON INITIAL CONDITIONS NATURE’S SENSORY DEVICE?
Authors: BROWN RAY , CHUA LEON , POPP BECKY
Published: November 2004

In this letter we illustrate three methods of using nonlinear devices as sensors. We show that the sensory features of these devices is a result of sensitive dependence on parameters which we show is equivalent to sensitive dependence on initial conditions. As a result, we conjecture that sensitive dependence on initial conditions is nature’s sensory device in cases where remarkable feats of sensory perception are seen.
CONTROLLING OF CHAOS IN BONHOEFFER- VAN DER POL OSCILLATOR
Authors: RAJASEKAR S. , LAKSHMANAN M.
Published: November 2004

In this letter controlling of chaos in Bonhoeffer-van der Pol oscillator is investigated using various different control algorithms. Specifically, using an adaptive control algorithm we analyse the resetting of the system dynamics from a chaotic attractor to a limit cycle attractor. We demonstrate that, starting from a chaotic regime, it is possible to bring the system to a regular regime by means of a small parametric perturbation as well as by the addition of a weak external force. It is then shown that one can eliminate chaotic evolution by stabilizing an unstable periodic orbit by making small adjustments to an external parameter. Finally, we show the suppression of chaos by adding appropriate external noise.
SINGULAR POINTS WITH TWO MULTIPLIERS, S1=−S2=1, IN THE BIFURCATION CURVES OF MAPS
Authors: CATHALA J.C. , KAWAKAMI H. , MIRA C.
Published: November 2004

Singularities with two multipliers, S1=−S2=1, organized in cascades by period doubling, are encountered in m-dimensional diffeomorphisms, m>2. It is shown that endormorphisms with m=2 give rise to singularities equivalent to those of diffeomorphisms with m>2.
CHAOS OR TURBULENCE?
Authors: BROWN RAY , CHUA LEON O.
Published: November 2004

We present a new three-dimensional autonomous chaotic dynamical system that appears to have a closer relationship to turbulence than the Lorenz system. We have developed this system using the new technique of dynamical synthesis.
NUMERICAL AND EXPERIMENTAL STUDIES OF SELF-SYNCHRONIZATION AND SYNCHRONIZED CHAOS
Authors: DE SOUSA VIEIRA M. , KHOURY P. , LICHTENBERG A. J. , LIEBERMAN M. A. , WONCHOBA W. , GULLICKSEN J. , HUANG J. Y. , SHERMAN R. , STEINBERG M.
Published: November 2004

We study self-synchronization of digital phase-locked loops (DPLL's) and the chaotic synchronization of DPLL's in a communication system which consists of three or more coupled DPLL's. Triangular wave signals, convenient for experiments, are employed. Numerical and experimental studies of two loops are in good agreement, giving bifurcation diagrams that show quasiperiodic, locked, and chaotic behavior. The approach to chaos does not show the full bifurcation sequence of sinusoidal signals. For studying synchronization to a chaotic signal, the chaotic carrier is generated in a subsystem of two or more self-synchronized DPLL's where one of the loops is stable and the other is unstable. The receiver consists of a stable loop. We verified numerically and experimentally that the receiver may synchronize with the transmitter if the stable loop in the transmitter and receiver are nearly identical and the synchronization degrades with noise and parameter variation. We studied the phase space where synchronization occurs, and quantify the deviation from synchronization using the concept of mutual information.
A KNOWLEDGE-BASED SYSTEM FOR CORRECTING USERS’ MISCONCEPTIONS IN DATABASE RETRIEVAL
Authors: WU XU , ICHIKAWA TADAO
Published: November 2004

A Cooperative Response system, which can detect and correct users’ misconceptions exhibited in database retrieval, is one of the most promising ways for applying the knowledge engineering approach to traditional database query systems. Misconceptions are generally regarded as users’ false beliefs about a database and are considered as a main source of failures in the database retrieval. How to handle users’ false beliefs has recently become an important point to overcome in advanced database front-end development.

While many efforts have been made to develop cooperative response systems, most of the work has placed emphasis on the detection of a user’s false beliefs revealed in a single query. No attention has been paid to handle users’ inconsistent beliefs which would be revealed in a sequence of contextual queries. In this paper, we propose a user-beliefs-modeling approach for detecting the inconsistent beliefs exhibited in two contextual queries. As an extension of the existing cooperative response systems, the system proposed in this paper can generate informative responses to correct users’ inconsistent beliefs.
A FRAMEWORK FOR MODELING SOFTWARE ENGINEERING PROCESSES
Authors: WEIDE BRUCE W. , DEFAZIO SAM
Published: November 2004

Summary—Software engineering processes must be understood to be managed effectively. It is important to go beyond purely metaphorical and descriptive methods to achieve such understanding. This paper proposes a framework, based on dynamic feedback control systems, for building potentially quantitative models of software engineering processes. It then uses this framework to explore some important characteristics of quantifiable outputs of such processes, including observability, measurability, independence, (near) continuity, and (near) monotonicity.

General Terms—Software engineering, process modeling.
THE PROGRAM SYSTEM FOR SOLVING OPTIMAL CONTROL PROBLEMS WITH PHASE CONSTRAINTS
Authors: TYATUSHKIN A.I. , ZHOLUDEV A.I. , ERINCHEK N.M.
Published: November 2004

In this paper, we present a program system for solving optimal control problems with phase constraints. The main idea of the method realized in the program system consists in successive solving auxiliary problems, which minimizes a special constructed Lagrange function, subject to linearized phase constraints. The linearly constrained auxiliary problems are more simple than the original ones because linear constraints can be easily processed. We shall discuss different aspects connected with approximating control problems and using the program system for solving them. We shall then pay attention to optimal control problems with constraints on inertia of control functions. For illustrations, two control problems will be solved using the proposed software.
VISIBILITY GRAPHS OF STAIRCASE POLYGONS WITH UNIFORM STEP LENGTH
Authors: ABELLO JAMES , EGECİOGLU ÖMER
Published: November 2004

Let Γn denote the collection of visibility graphs of staircase polygons (orthogonal convex fans) which consist of n−1 horizontal steps of arbitrary lengths. We show that for n≥7 there are graphs in Γn which cannot be realized as the visibility graphs of staircase polygons with uniform step length.
GENERALIZED INTERSECTION SEARCHING PROBLEMS
Authors: JANARDAN RAVI , LOPEZ MARIO
Published: November 2004

A new class of geometric intersection searching problems is introduced, which generalizes previously-considered intersection searching problems and is rich in applications. In a standard intersection searching problem, a set S of n geometric objects is to be preprocessed so that the objects that are intersected by a query object q can be reported efficiently. In a generalized problem, the objects in S come aggregated in disjoint groups and what is of interest are the groups, not the objects, that are intersected by q. Although this problem can be solved easily by using an algorithm for the standard problem, the query time can be Ω(n) even though the output size is just O(1). In this paper, algorithms with efficient, output-size-sensitive query times are presented for the generalized versions of a number of intersection searching problems, including: interval intersection searching, orthogonal segment intersection searching, orthogonal range searching, point enclosure searching, rectangle intersection searching, and segment intersection searching. In addition, the algorithms are also space-efficient.
SEPARATING SETS OF HYPERRECTANGLES
Authors: D’AMORE FABRIZIO , FRANCIOSA PAOLO GIULIO
Published: November 2004

We consider the problem of separating a set of d-dimensional non-overlapping isothetic hyperrectangles by means of one cutting isothetic hyperplane. If the cutting hyperplane crosses one hyperrectangle this is split into two non-overlapping hyperrectangles. We show that it always exists a cutting hyperplane that separates n given hyperrectangles into two sets each containing no more than [αd · n] hyperrectangles, where αd=(2d−1)/2d. Also, we show that there are instances for which it is not possible to do better.

An optimal O(d · n) time and space algorithm for finding this cutting hyperplane is presented.

An upper bound to the number of intersected hyperrectangles is also given, thus proving a separator theorem for hyperrectangles.
RECOGNITION OF AFFINE TRANSFORMED PLANAR CURVES BY EXTREMAL GEOMETRIC PROPERTIES
Authors: GOTSMAN CRAIG , WERMAN MICHAEL
Published: November 2004

An algorithm for the recognition of a digital image of a planar curve which has undergone an affine transformation is presented. The algorithm is based on affine-invariant extremal geometric properties of curves, utilizes existing computational-geometric methods, and is relatively insensitive to noise. Its time complexity is linear in the number of image pixels on the curve. Extensions of our algorithm to deal with some cases of occlusion of the image curve and recognition under perspective transformations are also described. These algorithms are almost linear in the number of image pixels on the curve.
ON MAINTAINING THE WIDTH AND DIAMETER OF A PLANAR POINT-SET ONLINE
Authors: JANARDAN RAVI
Published: November 2004

Efficient online algorithms are presented for maintaining the (almost-exact) width and diameter of a dynamic planar point-set, S. Let n be the number of points currently in S, let W and D denote the width and diameter of S, respectively, and let α>1 and β≥1 be positive, integer-valued parameters. The algorithm for the width problem uses O(αn) space, supports updates in O(α log 2 n) time, and reports in O(α log 2 n) time an approximation, Ŵ, to the width such that [Formula: see text]. The algorithm for the diameter problem uses O(βn) space, supports updates in O(β log n) time, and reports in O(β) time an approximation, [Formula: see text], to the diameter such that [Formula: see text]. Thus, for instance, even for α as small as 11, Ŵ/W≤1.01, and for β as small as 9, [Formula: see text]. All bounds stated are worst-case. Both algorithms, but especially the one for the diameter problem, use well-understood data structures and should be simple to implement. The diameter result yields a fast implementation of the greedy heuristic for maximum-weight Euclidean matching and an efficient online algorithm to maintain approximate convex hulls in the plane.
PERMUTATION IDENTITIES AND VARIETIES OF NILSEMIGROUPS
Authors: YAN XIAOYING
Published: November 2004

For any variety V of semigroups there exists a smallest semigroup variety PV containing V and closed for the construction of power semigroups. These varieties PV form a countably infinite subset PL(S) of the lattice L(S) of semigroup varieties. Though (PL(S), ⊆) is a complete lattice, it is not a complete sublattice of L(S). There exists however an interval in L(S) consisting of varieties of nilsemigroups which is isomorphic to (PL(S), ⊆). It will be shown that the equivalence classes of the equivalence relation induced by P: L(S)→PL(S), V↦PV, each contain a unique minimal variety consisting of nilsemigroups.
ENCODING IMAGES AS WORDS AND LANGUAGES
Authors: CULIK KAREL , DUBE SIMANT
Published: November 2004

We present some recently developed methods to describe, generate and encode a wide variety of images, in a mathematical formalism which uses terminology of words and of formal languages. It is shown how complex images including those with fractal (self-similar) geometries can be defined as languages, in particular regular languages, over a code alphabet in which symbols denote affine transformations and words are interpreted as compositions as these transformations. The problem of automatic encoding of images by these methods is addressed which leads to the method of recursive subdivisions.
THE WORD PROBLEM FOR THE RELATIVELY FREE SEMIGROUP SATISFYING Tm=Tm+n WITH m≥3
Authors: GUBA V.S.
Published: November 2004

Let m≥3, n≥1. In this article we show that the word problem for the relatively free Burnside semigroup satisfying Tm=Tm+n, is decidable.
A REMARK ABOUT COMBINGS OF GROUPS
Authors: BRIDSON MARTIN R. , GILMAN ROBERT H.
Published: November 2004

It is currently unknown whether or not there exist (synchronously) combable groups which are not automatic. This note settles an analogous question in a simpler context. The notion of a broomlike combing is introduced. It is shown that if a group admits a broomlike combing then it admits a broomlike combing in which the language of combing words is regular. A finitely generated group admits a broomlike combing if and only if it contains a free subgroup of finite index.
A PHASE CONJUGATE Nd:YAG LASER WITH BEAM STEERING
Authors: DIZIER F. , AYRAL J.-L. , MONTEL J. , HUIGNARD J.-P.
Published: November 2004

We analyse the competitive effects which alter the stability of SBS phase conjugate mirrors when the laser operates at repetition rates between 10 and 30 Hz. Satisfactory results are obtained with nitrogen gas cell at 180 Atm. We also propose and experimentally demonstrate a SBS phase-conjugate Nd:YAG laser source with a beam steering function. The laser, designed as an oscillator-amplifier configuration, incorporates a TeO 2 acousto-optic deflector on the low energy beam. The high energy beam (100–185 mJ) is thus deflected over 2.7° and 40 resolved beam directions are obtained with 5 µs access time.
ALL-OPTICAL ASYMMETRIC FABRY-PEROT REFLECTION MODULATORS
Authors: OHTSUKI T. , KROL M.F. , KHITROVA G. , JIN R. , BONCEK R.K. , MCGINNIS B.P. , GIBBS H.M. , PEYGHAMBARIAN N.
Published: November 2004

Operating conditions of all-optical asymmetric Fabry-Perot modulators are discussed based on the experimental results of two modulators with different nonlinear spacers of GaAlInAs/AlInAs and strained-layer InGaAs/GaAs multi-quantum wells. These modulators operate at wavelengths of 1.3 and 0.92 µm, and offer an on/off contrast ratio of greater than 1000:1. An “on” state with an insertion loss of 2.2 dB existed for pump intensities of 30 kW/cm 2 and 3 kW/cm 2, respectively. The corresponding carrier densities for these pump intensities are approximately the same, at 4×1017 cm –3. The switching pump beam intensity of the modulator and its response time are analyzed in terms of saturation carrier density and carrier lifetime of the nonlinear spacer material. Requirements for the nonlinear spacer material and device parameters are discussed for low power and fast modulators.
INTENSITY DEPENDENT NONLINEAR MATERIAL REQUIREMENTS FOR PASSIVE OPTICAL LIMITING
Authors: WOOD G.L. , SHARP E.J.
Published: November 2004

Passive optical limiting devices based on nonlinear optical (NLO) materials exhibit a throughput radiation level that is related to the magnitude of the nonlinear material parameters. We model both optically ‘thick’ and optically ‘thin’ limiters based on intensity dependent, χ(3) nonlinearities and predict the magnitude of the nonlinearities required to provide protection for the human eye from laser induced damage for a specific optical system. These calculated nonlinearities are given in terms of a required index change, n2, or absorption change, β.