bluuebunny/crossref_metadata_2025 huggingface dataset:
REFLEXIVE POLYHEDRA, WEIGHTS AND TORIC CALABI-YAU FIBRATIONS
Authors: KREUZER MAXIMILIAN , SKARKE HARALD
Published: July 2002

During the last years we have generated a large number of data related to Calabi-Yau hypersurfaces in toric varieties which can be described by reflexive polyhedra. We classified all reflexive polyhedra in three dimensions leading to K3 hypersurfaces and have also completed the four-dimensional case relevant to Calabi-Yau threefolds. In addition, we have analysed for many of the resulting spaces whether they allow fibration structures of the types that are relevant in the context of superstring dualities. In this survey we want to give background information both on how we obtained these data, which can be found at our web site, and on how they may be used. We give a complete exposition of our classification algorithm at a mathematical (rather than algorithmic) level. We also describe how fibration structures manifest themselves in terms of toric diagrams and how we managed to find the respective data. Both for our classification scheme and for simple descriptions of fibration structures the concept of weight systems plays an important role.
The Moduli Space of Yang–Mills Connections Over a Compact Surface
Authors: Sengupta Ambar
Published: July 2002

Yang–Mills connections over closed oriented surfaces of genus ≥1, for compact connected gauge groups, are constructed explicitly. The resulting formulas for Yang–Mills connections are used to carry out a Marsden–Weinstein type procedure. An explicit formula is obtained for the resulting 2-form on the moduli space. It is shown that this 2-form provides a symplectic structure on appropriate subsets of the moduli space.
TWO-DIMENSIONAL COULOMB INTERACTIONS IN A MAGNETIC FIELD
Authors: XIA JINGBO
Published: July 2002

We consider the 2D Hamiltonian of N charged particles in a magnetic field. We show how the Coulomb interactions cause the first Landau level to split in the essential spectrum.
THE SIMULATION OF THE 2D FERROMAGNETIC BLUME–CAPEL MODEL ON A CELLULAR AUTOMATON
Authors: KUTLU B.
Published: July 2002

The two-dimensional ferromagnetic Blume–Capel model is simulated on a cellular automaton, which based on the Creutz cellular automaton for square lattice. The values of the critical temperature and the static critical exponents are estimated within the framework of the finite-size scaling theory for 0 ≤ D/J ≤ 1.5. The results are compatible with the universal Ising critical behavior.
A MONTE CARLO STUDY OF THE STORAGE CAPACITY AND EFFECTS OF THE CORRELATIONS IN q-STATE POTTS NEURON SYSTEM
Authors: AKCAN BURCU , GÜNDÜÇ YİĞIT
Published: July 2002

The storage capacity of the Potts neural network is studied by using Monte Carlo techniques. It is observed that the critical storage capacity formula of Kanter fits well to our data. The increase of the correlation between the initial patterns reduces the storage capacity. This reduction in capacity is proportional to the percentage of correlations and inversely proportional to the number of orientations that the Potts neurons can possess
ENERGY AND MOMENTUM OF A STATIONARY BEAM OF LIGHT
Authors: BRINGLEY THOMAS
Published: July 2002

The energy–momentum complexes of Einstein, Landau–Lifshitz, Papapetrou, and Weinberg give the same and meaningful results for the energy and momentum of the Bonnor space–time describing the gravitational field of a stationary beam of light. The results support the Cooperstock hypothesis.
BOSONIC FIELDS WITH TWO MASS AND SPIN STATES
Authors: KRUGLOV S. I.
Published: July 2002

We consider the bosonic fields which describe a particle which may exist in states with spins one and zero with different masses. All the linearly independent solutions of the equation for a free particle are obtained in the form of the projection matrix-dyads (density-matrices). The interaction with anomalous magnetic dipole and quadruple electric moments of a particle is studied. The Hamiltonian form of the first order equation has been investigated.
NONCOMMUTATIVE GEOMETRY, GEOMETRICAL ASPECTS OF SKYRMIONS AND STRING THEORY
Authors: BANDYOPADHYAY PRATUL
Published: July 2002

It is pointed out here that noncommutative geometry having the space–time manifold X = M4× Z2leads to the description of a massive fermion as a skyrmion when the discrete space–time is incorporated as an internal variable. The inherent anisotropic feature of the internal space gives rise to the Skyrme term as well as the Wess–Zumino term. An array of such skyrmions may be considered as a three-dimensional Ising system. It is shown that the composite system of such skyrmions may be viewed as the (3 + 1)-dimensional relative of the Polyakov string theory when the associated Liouville field corresponds to the attachment of topological fixtures like vortex lines at the end points of an open string. These two systems are found to satisfy certain duality principles through conformal duality which are similar to T duality and S duality in conventional string picture.
PRODUCT INTEGRALS AND WILSON LOOPS
Authors: KARP ROBERT L.
Published: July 2002

Using product integrals we review the unambiguous mathematical representation of Wilson line and Wilson loop operators, including their behavior under gauge transformations and the non-abelian Stokes theorem. Interesting consistency conditions among Wilson lines are also presented.
ANALYSIS OF SU(3)c⊗SU(3)L ⊗U(1)X LOCAL GAUGE THEORY
Authors: PONCE WILLIAM A. , FLÓREZ JUÁN B. , SÁNCHEZ LUIS A.
Published: July 2002

Six different models, straightforward extensions of the standard model to of SU (3)c ⊗ SU (3)L ⊗ U (1)X, which do not contain particles with exotic electric charges are presented. Two of the models are one family and four are three family models. In two of the three family models one of the families transforms different from the others, and in the other two all the three families are different.
EXACT SOLUTIONS TO THE TWO-DIMENSIONAL BF AND YANG–MILLS THEORIES IN THE LIGHT-CONE GAUGE
Authors: ABE MITSUO , NAKANISHI NOBORU
Published: July 2002

It is shown that the BRS (= Becchi–Rouet–Stora)-formulated two-dimensional BF theory in the light-cone gauge (coupled with chiral Dirac fields) is solved very easily in the Heisenberg picture. The structure of the exact solution is very similar to that of the BRS-formulated two-dimensional quantum gravity in the conformal gauge. In particular, the BRS Noether charge has anomaly. Based on this fact, a criticism is made on the reasoning of Kato and Ogawa, who derived the critical dimension D=26 of string theory on the basis of the anomaly of the BRS Noether charge. By adding the [Formula: see text] term to the BF-theory Lagrangian density, the exact solution to the two-dimensional Yang–Mills theory is also obtained.
AN EXTENDED ABELIAN CHERN–SIMONS MODEL AND THE SYMPLECTIC PROJECTOR METHOD
Authors: MANSSUR L. R. U. , NOGUEIRA A. L. M. A. , SANTOS M. A.
Published: July 2002

The symplectic projector method is applied to discuss quantization aspects of an extended Abelian model with a pair of gauge potentials coupled by means of a mixed Chern–Simons term. We focus on a field content that spans an N=2-D=3 supersymmetric theory whenever scalar and fermionic matter is suitably coupled to the family of gauge potentials.
DYNAMICAL PROCESS OF PHOTOIONIZATION IN SEMICONDUCTOR NANOCRYSTALS
Authors: SHEN M. Y. , ODA M. , GOTO T. , YAO T.
Published: July 2002

When quantum dots (QDs) or nanocrystals (NCs) are photoionized, great changes of electric fields exerted on QDs occur, then photodarkening, photobrightening, and persistent hole burning effects may be macroscopically observed in QD system, and luminescence spectral diffusion and on/off behavior may be microscopically observed in a single QD. The dynamics of the emitted carrier from the QD by photoionization governs the properties of these phenomena. The photoionization process has been directly found in CdTe nanocrystals embedded in TOPO by measuring the temperature dependence of their photocurrent and photoluminescence. The phase transition of the matrix TOPO from amorphous solid to liquid makes the diffusion length of the emitted carriers outside the nanocrystals increase abruptly, resulting in a steep rise in both the photocurrent and the photoluminescence. Photoionization of a QD is fundamentally important to its optical properties
A THEORETICAL STUDY OF BISTABILITY OF POLYDIACETYLENE: TCDU(poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)
Authors: KATAGIRI HIDEKI , SHIMOI YUKIHIRO , ABE SHUJI
Published: July 2002

We performed a first-principles calculation of typical polydiacetylene (PDA), TCDU (poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)). Potential energy curves (PEC's) as a function of two bond lengths of the backbone chain are presented. The present PEC's show that TCDU has only an acetylene-type stable structure and a butatriene-type structure is unstable, consistent with our previous calculations with a geometry optimization procedure. This result is in contrast to the case of a hypothetical hydrogen-substituted PDA where a butatriene-type structure is obtained as a meta-stable structure.
THEORY OF OPTICAL RESPONSES OF SPHERICAL QUANTUM DOTS UNDER STATIC AND DYNAMICAL EXTERNAL FIELDS
Authors: UOZUMI TAKAYUKI , KAYANUMA YOSUKE
Published: July 2002

The influence of an external electric charge on optical properties of a spherical quantum dot (QD) is theoretically investigated within the effective-mass approximation. The absorption spectrum of QD is strongly affected when the electric charge approaches close to the surface of QD: the lowest excited state shows a rapid red-shift and partially loses its oscillator strength. The magnitude of the red-shift and the reduction rate of the oscillator strength in such a case shows a characteristic change as a function of the dot-size: the former monotonously increases as the dot-size is reduced, while the latter reaches its maximum when the dot-size corresponds to that of the intermediate confinement regime.
A PAIR POTENTIAL FOR THE COOPER PAIR IN THE HIGH-Tc CUPRATES
Authors: LIU FU-SUI , CHEN WAN-FANG , CHEN T.-P. , WANG J. T.
Published: July 2002

Taking the two-local-spin-mediated interaction (TLSMI) as the pair potential for the Cooper pair and considering the long-range phase coherence (LRPC), the empirical formula of T c versus hole doping is explained and the physical picture for the pseudogap and the gap in superconductive state is set up. The superconductivity in PrBa 2 Cu 3 O 7-δ and CuCl at high pressure and Fe 1-x S is discussed.
Conductivity in Electrorheology
Authors: Conrad H. , Wu C. W. , Tang X.
Published: July 2002

Analytical models for the quasi-static ER behavior of suspensions have been developed which take into consideration both the conductivity and dielectric mismatches between the components and the supra-ohmic behavior of the host liquid. Included are models for: (a) slightly conducting particles, (b) insulating particles with a conducting film and (c) highly conducting particles with an insulating film. Both dc and ac fields are treated. Good agreement between predicted and experimental results occur. The models indicate that promising ER suspensions for use over a wide frequency range are those which contain highly conducting particles coated with an "insulating" film which has a hihg dielectric constant and a high electrical breakdown strength. It is conceivable that with proper desigh a yield strength of 20–100 kPa may be obtained with an acceptable current density.
Hysteresis Behaviors of Poly (Naphthalene Quinone) Radical Electrorheological Fluid
Authors: Choi Hyoung J. , Cho Min S. , Jhon Myung S.
Published: July 2002

As a potential electrorheological(ER) material, poly(naphthalene quinone) radical (PNQR) ER fluid was prepared, and its rheological behavior and hysteresis phenomenon were investigated. PNQR was synthesized by Friedel-Crafts acylation between naphthalene and phthalic anhydride, using zinc chloride as a catalyst at 256°C. A Physica rheometer equipped with a high voltage generator was used to measure the rheological properties of the ER fluids, which were prepared by dispersing PNQR in silicone oil at several particle concentrations. Shear stresses were observed to decrease as shear rate increased in the region of slow deformation rate. It was further found that ER fluid showed different hysteresis behaviors according to the shear rate ranges; thixotropy was observed in the low shear rate region (0.007-0.51/s) and anti-thixotropy in the high shear rate region (0.5-10001/s). Controlled shear stress mode was also applied to observe similar behaviors.
Coating of Polyaniline with an Insulating Polymer to Improve the Power Efficiency of Electrorheological Fluids
Authors: Akhavan J. , Slack K. , Wise V. , Block H.
Published: July 2002

Currents drawn under high fields often present practical limitations to electrorheological (ER) fluids usefulness. For heavy-duty applications where large torques have to be transmitted, the power consumption of a ER fluid can be considerable, and for such uses a current density of ~100μ A cm -2 is often taken as a practical upper limit. This investigation was conducted into designing a fluid which has little extraneous conductance and therefore would demand less current.

Selected semi-conducting polymers provide effective substrates for ER fluids. Such polymers are soft insoluble powdery materials with densities similar to dispersing agents used in ER formulations. Polyaniline is a semi-conducting polymer and can be used as an effective ER substrate in its emeraldine base form. In order to provide an effective ER fluid which requires less current polyaniline was coated with an insulating polymer. The conditions for coating was established for lauryl and methyl methacrylate. Results from static yield measurements indicate that ER fluids containing coated polyaniline required less current than uncoated polyaniline i.e. 0.5μ A cm -2. The generic type of coating was also found to be important.
COMPLEMENTARY HISTORIES AND COLLAPSE INTO THE PAST IN STANDARD QUANTUM MECHANICS
Authors: ORLOV YURI F.
Published: July 2002

It follows from the standard quantum formalism that in the time between any two noncommuting measurements there are two quantum states of the same system representing two complementary, forward and backward histories, histories that may be observed in two complementary experiments. It follows from this in turn that all interpretations of quantum mechanics based on the idea of a single state between measurements should be rejected. The non-existence of a faster-than-light nonlocality and of paradoxes in EPR-type experiments1 can be proved in the frame of the standard formalism when the reality of backward histories is taken into account.
TUNNELING SPECTRA AND SUPERCONDUCTING GAP IN Bi2Sr2CaCu2O8+δ AND Tl2Ba2CuO6+δ
Authors: OZYUZER L. , ZASADZINSKI J. F. , MIYAKAWA N.
Published: July 2002

Tunneling spectra are reported for Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) over a wide doping range using superconductor-insulator-superconductor (SIS) break junctions. The energy gap inferred from the tunneling data displays a remarkable monotonic dependence on doping, increasing to very large values in the underdoped region even as T c decreases. This leads to unphysically large values of the strong coupling ratio (~20). The tunneling spectra are qualitatively similar over the entire doping range even though the gap parameter, Δ, changes from 12 meV to 60 meV. Each spectrum exhibits dip and hump features at high bias with characteristic energies that scale with the superconducting gap. Tunneling spectra of near optimally-doped Tl 2 Ba 2 CuO 6+δ (Tl-2201) also display a weak dip feature in superconductor-insulator-normal metal (SIN) junctions. Generated SIS spectra of Tl-2201 are compared with measured spectra on Bi-2212 and it is concluded that the dip and hump features are generic to high temperature superconductors.
GROWTH AND CHARACTERIZATION OF GaAs BY METALORGANIC CHEMICAL VAPOR DEPOSITION USING TRIETHYLGALLIUM AND SOLID ARSENIC
Authors: ESPARZA A. , GALVÁN M. , CASTILLO R. , SÁNCHEZ M. , SIERRA R. PEÑA , ESCOBOSA A.
Published: July 2002

GaAs-low compensated layers were grown by using an atmospheric MOCVD system. Solid arsenic and triethylgallium (TEG) were used as precursors. The layers exhibit an electron mobility greater than 30,000 cm2/V-sec at 77K for best growing conditions. This is the highest value reported until now for MOCVD GaAs grown by using non-arsine based alternative arsenic sources. The resulting layers were n-type with a minimum electron concentration of 1015 cm-3. The DLTS studies shown the EL2 electron level as the dominant trap with a concentration of 1013 cm-3.
TRANSFORMATIONS OF q-BOSON AND q-FERMION ALGEBRAS
Authors: NARAYANA SWAMY P.
Published: July 2002

We investigate the algebras satisfied by q-deformed boson and fermion oscillators, in particular the transformations of the algebra from one form to another. Based on a specific algebra proposed in recent literature, we show that the algebra of deformed fermions can be transformed to that of undeformed standard fermions. Furthermore, we also show that the algebra of q-deformed fermions can be transformed to that of undeformed standard bosons.
Time Decay of Correlations in a Spin-1/2 Linear Chain
Authors: Bolina Oscar , Parreira J. Rodrigo
Published: July 2002

We determine the asymptotic behavior of time-dependent correlation functions in a spin-[Formula: see text] infinite linear chain with a strong transverse magnetic field in terms of the energy gap of the ground state against the excited ones.
MAGNETIC PROPERTIES OF Ti-Co SOLID SOLUTIONS
Authors: POP IULIU , POP OLIVIA
Published: July 2002

Thermal variation of the magnetic susceptibility for Ti-Co solid solutions is reported. Cobalt, by alloying acts on the transition Néel temperature giving rise to a complicated magnetic phase diagram. The change of the Fermi level is the main mechanism in the critical temperature, T N , shift.
CHAOTIC BURSTS AND BIFURCATION IN CHAOTIC NEURAL NETWORKS WITH RING STRUCTURE
Authors: KITAJIMA HIROYUKI , YOSHINAGA TETSUYA , AIHARA KAZUYUKI , KAWAKAMI HIROSHI
Published: July 2002

We investigate a noninvertible map describing burst firing in a chaotic neural network model with ring structure. Since each neuron interacts with many other neurons in biological neural systems, it is important to consider global dynamics of networks composed of nonlinear neurons in order to clarify not only mechanisms of emergence of the burst firing but also its possible functional roles. We analyze parameter regions in which burst firing can be observed, and show that dynamics of strange attractors with burst firing is related to the generation of a homoclinic-like situation and vanishing of an invariant closed curve of the map.
HETEROCLINIC ORBITS FOR MONOTONE TWIST MAPS THROUGH A VARIATIONAL PRINCIPLE
Authors: QIAN TIFEI
Published: July 2002

The variational method has shown many advantages over the geometric method in proving the existence of connecting orbits since it requires much weaker hyperbolicity and less smoothness. Many results known to be difficult to obtain by the geometric method can now be obtained by a variational principle with relative ease. In particular, a variational principle provides a constructive approach to the existence of heteroclinic orbits. In this paper a variational principle is used to construct a heteroclinic orbit between an adjacent minimal pair of fixed points for monotone twist maps on (ℝ/ℤ) × ℝ. Application of our results to a standard map is also given.
ROBUST DEAD-BEAT SYNCHRONIZATION AND COMMUNICATION FOR DISCRETE-TIME CHAOTIC SYSTEMS
Authors: LIAN KUANG-YOW , LIU PETER , CHIU CHIAN-SONG , CHIANG TUNG-SHENG
Published: July 2002

This paper proposes synchronization and chaotic communication for a class of Lur'e type discrete-time chaotic systems. The scalar outputs are suitably chosen in a flexible manner to be linear, nonlinear, or predictive, and along with the drive system are then written in an output injection form. Then with a suitable design of an observer-based response system, dead-beat performance is achieved for synchronization and chaotic communications. Then disturbances in the drive system are considered. Using an ℋ∞performance criterion, the disturbance is attenuated to a prescribed level by solving linear matrix inequalities (LMIs). Numerical simulations are carried out to verify the dead-beat performance.
ON OBSERVABILITY OF 3D CONTINUOUS-TIME AUTONOMOUS CHAOTIC SYSTEMS BASED ON SCALAR OUTPUT MEASUREMENT
Authors: YANG XIAO-SONG
Published: July 2002

In this paper, by means of case studies we discuss an observable feature of 3D continuous-time autonomous chaotic systems through scalar output and its time derivatives. We observe that the Lorenz system, the Rössler system, the Chua circuit and the Chen system are all observable based on scalar output and its derivatives. This leads to our conjecture that chaotic motion described by 3D continuous-time autonomous dynamical system is observable based on a scalar output and its first- and second-order derivatives. Finally, we present some mathematical analysis and put up some theoretical questions for future studies.
SYNTHESIS OF SYNCHRONIZED CHAOTIC SYSTEMS BASED ON OBSERVERS
Authors: USHIO TOSHIMITSU
Published: July 2002

This paper proposes an observer-based approach to synthesis of synchronized chaotic systems. We consider a linear system with nonlinear feedback which exhibits chaos. Using an observer for the linear system, we design synchronized chaotic systems. Moreover, we introduce a new concept of synchronization called (M, c)-synchronization. We also propose a synthesis method for (M, c)-synchronized systems by modifying the observer-based method.
PERIODIC RESPONSE TO EXTERNAL STIMULATION OF A CHAOTIC NEURAL NETWORK WITH DELAYED FEEDBACK
Authors: TSUI ALBAN PUI MAN , JONES ANTONIA J.
Published: July 2002

We construct a feedforward neural network so that when the outputs are fed back into the inputs and the system is iterated it behaves chaotically. We call this the "rest state". Suppose now that an input stimulus is added to one or more inputs. Following a biologically inspired model suggested by Freeman [1991], under these conditions we should want the behavior of the network to stabilize into an unstable periodic orbit of the original system. We call this the "retrieval behavior" since it is analogous to the act of recognition. Standard methods of chaos control, such as OGY for example, used to elicit the retrieval behavior would be inappropriate, since such methods involve calculations external to the system being controlled and can be considered unlikely in a biological neural network. Using a chaos control method originally suggested by Pyragas [1992] we show that retrieval behavior can occur as a result of delayed feedback and examine the variety of the responses that arise under different types of stimuli and under noise. This artificial neural system has a strong dynamical parallel to Freeman's observed biological phenomenon.
DUALITY OF NORMALLY PRESENTED VARIETIES
Authors: CHAJDA I. , HALAŠ R. , PINUS A. G. , ROSENBERG I. G.
Published: July 2002

Let [Formula: see text] be a variety of the form [Formula: see text] where [Formula: see text] is a finite subdirectly irreducible algebra. We show that if [Formula: see text] is naturally dualizable (in the sense of D. M. Clark and B. A. Davey, i.e. with respect to the discrete topology) then the variety [Formula: see text][Formula: see text] determined by all normal identities of [Formula: see text] (the so called nilpotent shift of [Formula: see text]) is also naturally dualizable. We give a finite algebra [Formula: see text] and a relational system [Formula: see text], constructed explicitly from the system [Formula: see text] for [Formula: see text], such that [Formula: see text] and [Formula: see text] dualizes [Formula: see text] .
A CHARACTERIZATION OF de MORGAN ALGEBRAS
Authors: BRZOZOWSKI J. A.
Published: July 2002

In this note we show that every de Morgan algebra is isomorphic to a two-subset algebra, < P,⊔,⊓,~,0P,1P>, where P is a set of pairs (X,Y) of subsets of a set I, (X,Y)⊔ (X′,Y′)=(X∩ X′,Y∪ Y′),(X,Y) ⊓ (X′,Y′)=(X∪ X′,Y∩Y′),~(X,Y)= (Y,X), 0P=(I,∅) and 1P=(∅,I). This characterization generalizes a previous result that applied only to a special type of de Morgan algebras called ternary algebras.
HOMOLOGICAL DECISION PROBLEMS FOR FINITELY GENERATED GROUPS WITH SOLVABLE WORD PROBLEM
Authors: BOGLEY W. A. , HARLANDER J.
Published: July 2002

We show that for finitely generated groups P with solvable word problem, there is no algorithm to determine whether H1(P) is trivial, nor whether H2(P) is trivial.
A SCALABLE DISTRIBUTED MULTIMEDIA KNOWLEDGE RETRIEVAL SYSTEM ON A CLUSTER OF HETEROGENEOUS HIGH PERFORMANCE ARCHITECTURES
Authors: RYAN STEPHEN W. , BANSAL ARVIND K.
Published: July 2002

This paper describes a system to distribute and retrieve multimedia knowledge on a cluster of heterogeneous high performance architectures distributed over the Internet. The knowledge is represented using facts and rules in an associative logic-programming model. Associative computation facilitates distribution of facts and rules, and exploits coarse grain data parallel computation. Associative logic programming uses a flat data model that can be easily mapped onto heterogeneous architectures. The paper describes an abstract instruction set for the distributed version of the associative logic programming and the corresponding implementation. The implementation uses a message-passing library for architecture independence within a cluster, uses object oriented programming for modularity and portability, and uses Java as a front-end interface to provide a graphical user interface and multimedia capability and remote access via the Internet. The performance results on a cluster of IBM RS 6000 workstations are presented. The results show that distribution of data improves the performance almost linearly for small number of processors in a cluster.
AGENTS FOR QUERYING DISTRIBUTED STATISTICAL DATABASES OVER THE INTERNET
Authors: McCLEAN SALLY , KARALI ISAMBO , SCOTNEY BRYAN , GREER KIERAN , KAPOS GEORGIOS-DIMITRIOS , PAIRCEIR RONAN , HONG JUN , BELL DAVID , HATZOPOULOS MICHALIS
Published: July 2002

Distributed database techniques and the Internet provide producers of statistics with a means to publish their data and metadata widely and make them available to a variety of users. Data matching to a user query and data access as well as data harmonization are some of the problems that should be solved. Intelligence is required in various stages of query answering and data matching. Moreover, the breadth and distributed nature of the Internet urge for a distributed approach. Agents seem to be the means by which both intelligence and distributed processing can be achieved. This paper presents a distributed approach for answering queries on statistical data that exist over the Internet using a multi-agent framework.
COMBED 3-MANIFOLDS WITH CONCAVE BOUNDARY, FRAMED LINKS, AND PSEUDO-LEGENDRIAN LINKS
Authors: BENEDETTI RICCARDO , PETRONIO CARLO
Published: July 2002

We provide combinatorial realizations, according to the usual objects/moves scheme, of the following three topological categories: (1) pairs (M, v) where M is a 3-manifold (up to diffeomorphism) and v is a (non-singular vector) field, up to homotopy; here possibly ∂M≠∅, and v may be tangent to ∂M, but only in a concave fashion, and homotopy should preserve tangency type; (2) framed links L in M, up to framed isotopy; (3) triples (M, v, L), with (M, v) as above and L transversal to v, up to pseudo-Legendrian isotopy (transverality-preserving simultaneous homotopy of v and isotopy of L). All realizations are based on the notion of branched standard spine, and build on results previously obtained, Links are encoded by means of diagrams on branched spines, where the diagram is C1with respect to the branching. Several motivations for being interested in combinatorial realizations of the topological categories considered in this paper are given in the introduction. The encoding of links is suitable for the comparison of the framed and the pseudo-Legendrian categories, and some applications are given in connection with contact structures, torsion and finite-order invariants. An estension of Trace's notion of winding number of a knot diagram is introduced and discussed.
CHEMICAL EVOLUTION OF STRONGLY MAGNETIZED QUARK CORE IN A NEWBORN NEUTRON STAR
Authors: GHOSH TANUSRI , CHAKRABARTY SOMENATH
Published: July 2002

The chemical evolution of nascent quark matter core in a newborn compact neutron star is studied in presence of a strong magnetic field. The effective rate of strange quark production in degenerate quark matter core in presence of strong magnetic fields is obtained. The investigations show that in presence of strong magnetic field the quark matter core becomes energetically unstable and hence a first/higher order deconfinement transition to quark matter at the centre of a compact neutron star under such circumstances is absolutely impossible. The critical strength of magnetic field at the central core to make the system energetically unstable with respect to dense nuclear matter is found to be ~4.4 × 1013 G. This is the typical strength at which the Landau levels for electrons are populated. The other kind of phase transformations at such high density and ultra strong magnetic field environment are discussed.
THE R-MODE INSTABILITY IN ROTATING NEUTRON STARS
Authors: ANDERSSON NILS , KOKKOTAS KOSTAS D.
Published: July 2002

In this review we summarize the current understanding of the gravitational-wave driven instability associated with the so-called r-modes in rotating neutron stars. We discuss the nature of the r-modes, the detailed mechanics of the instability and its potential astrophysical significance. In particular we discuss results regarding the spin-evolution of nascent neutron stars, the detectability of r-mode gravitational waves and mechanisms limiting the spin-rate of accreting neutron stars in binary systems.
MINKOWSKI FUNCTIONALS AND CLUSTER ANALYSIS FOR CMB MAPS
Authors: NOVIKOV D. , FELDMAN HUME A. , SHANDARIN SERGEI F.
Published: July 2002

We suggest novel statistics for the CMB maps that are sensitive to non-Gaussian features. These statistics are natural generalizations of the geometrical and topological methods that have been already used in cosmology such as the cumulative distribution function and genus. We compute the distribution functions of the Partial Minkowski Functionals for the excursion set above or bellow a constant temperature threshold. Minkowski Functionals are additive and are translationally and rotationally invariant. Thus, they can be used for patchy and/or incomplete coverage. The technique is highly efficient computationally (it requires only O(N) operations, where N is the number of pixels per one threshold level). Further, the procedure makes it possible to split large data sets into smaller subsets. The full advantage of these statistics can be obtained only on very large data sets. We apply it to the 4-year DMR COBE data corrected for the Galaxy contamination as an illustration of the technique.
ELECTRICALLY CHARGED COLD BLACK HOLES IN SCALAR-TENSOR THEORIES
Authors: BRONNIKOV K. A. , CONSTANTINIDIS C. P. , EVANGELISTA R. L. , FABRIS J. C.
Published: July 2002

We study the possible existence of charged black holes in the Bergmann–Wagoner class of scalar-tensor theories (STT) of gravity in four dimensions. The existence of black holes is shown for anomalous versions of these theories, with a negative kinetic term in the Lagrangian. The Hawking temperature T H of these holes is zero, while the horizon area is (in most cases) infinite. As a special case, the Brans–Dicke theory is studied in more detail, and two kinds of infinite-area black holes are revealed, with finite and infinite proper time needed for an infalling particle to reach the horizon; among them, analyticity properties select a discrete subfamily of solutions, parametrized by two integers, which admit an extension beyond the horizon. The causal structure and stability of these solutions with respect to small radial perturbations is discussed. As a by-product, the stability properties of all spherically symmetric electrovacuum STT solutions are outlined.
HIGH-ENERGY APPROXIMATION FOR NUCLEUS–NUCLEUS SCATTERING
Authors: LUKYANOV V. K. , ZEMLYANAYA E. V.
Published: July 2002

The high-energy approximation is adapted for heavy ion scattering at energies of several dozen MeV/nucleon. It is shown that the closed form of the eikonal phase suggested for the realistic Woods–Saxon type potential is a hopeful one for further applications. The Glauber–Sitenko small angle approach is analyzed, and a role of the Coulomb deviation of the straight trajectory of motion is investigated. Methodical calculations and comparison with experimental data are made.
DETERMINATION OF AN OPTIMAL SETTING AND PRODUCTION RUN USING TAGUCHI'S LOSS FUNCTION
Authors: PAKKALA T. P. M. , RAHIM M. A.
Published: July 2002

This paper considers the problem of selecting an optimal setting of the process mean and an optimal production run for a continuous production process. The process is subject to gradual shifts in the process mean due to occurrences of some random shocks. The product output becomes nonconforming only when the process experiences a certain number of accumulated shocks. The changes in the process mean are assumed to follow a nonhomogeneous Poisson process. A quadratic loss function, which is a general form of Taguchi's loss function, is utilized for developing the economic model in determining an initial resetting process mean and an optimal production run. Some new results are derived and some interesting findings are reported.
GREATLY IMPROVED SURFACE STRUCTURE DATABASE — SSD VERSION 3
Authors: VAN HOVE M. A. , HERMANN K. , WATSON P. R. , RUMBLE J.
Published: July 2002

SSD-3, the third version of the NIST Surface Structure Database, appeared in 1999 as a major update. A complete revision of the database and graphics software upgrades SSD to a Windows environment (MS Windows 95, 98 and NT). SSD-3 includes over 1100 structures published through the end of 1997. SSD is an interactive PC-based database of critically selected surface structures determined with a variety of experimental techniques. The data include not only atomic coordinates, bond lengths and bond angles, but also information about experimental preparation, measurement and analysis methods. The software provides advanced search and display facilities, as well as interactive three-dimensional color visualization and analysis tools of great flexibility. In addition, the program can generate publication-quality color or gray-scale prints of any structure, with a host of user-selectable options (such as view angle, perspective, colors, ball and bond styles, and labels).
EPITAXIAL GROWTH OF SrF2 ON Ge(111)-c(2×8) AS STUDIED BY PHOTOELECTRON DIFFRACTION AND HOLOGRAPHY
Authors: OMORI S. , KOZAKAI T. , NIHEI Y.
Published: July 2002

We have investigated the photoelectron diffraction (PED) from a SrF 2 epitaxial thin film on Ge(111) from the viewpoint of holographic inversion for imaging the atomic structure. The holographic interference fringes were retrieved from the PED pattern including a wide variety of diffraction features via averaging the pattern around each forward-scattering peak. Furthermore, another method for enhancing holographic fringes by subtracting one photoelectron hologram from another at slightly different kinetic energies was theoretically investigated.
Comminuted, Imapacted Fractures at the Base of the Middle Phalanx of the Finger, Treated by Open Reduction and Internal Fixation: Short-Term Results in 38 Cases
Authors: Nagy L. , Büchler U. , Birkbeck D.
Published: July 2002

Thirty-eight patients with comminuted and impacted fractures at the base of the middle phalanx of the finger involving, on average, 60% of the joint plateau were treated by open reduction, cancellous bone grafting as necessary and minimal internal and/or external fixation. The results were evaluated after a mean follow-up time of 14 months. All patients were satisfied with the outcome and returned to their previous occupations after nine weeks on average. Forty-two percent of patients achieved a good result (no pain, proximal interphalangeal joint flexion/extension better than 90°/–15°, full functional use and good radiographic appearance); 32% had an acceptable result and 13% an unsatisfactory global result. The quality of anatomical reconstruction was the most significant factor determining the final outcome.
BILATERAL SUPRASCAPULAR ENTRAPMENT NEUROPATHY: A CASE REPORT
Authors: Cooper Timothy M. , Steimnitz Jules P. , Buncke Harry J.
Published: July 2002

Suprascapular nerve entrapment is an uncommon condition. It is not often included in the differential diagnosis of shoulder pain and is therefore probably underdiagnosed. The nerve may be compressed at either the suprascapular notch or spinalglenoid notch.

The clinical presentation is often unremarkable with poorly localised pain over the posterolateral shoulder, which tends to become persistent. There is often a history of minor trauma or repeated exertion. Weakness of external rotation and abduction may be present and in advanced cases there is wasting of the supraspinatous and infraspinatous muscles. There may be tenderness over the suprascapular notch. Diagnosis is established with EMG findings of delayed nerve root conduction and/or denervation potentials in the involved muscles.
EFFICIENCY, INCENTIVES, AND COMPUTATIONAL TRACTABILITY IN MAS-COORDINATION
Authors: GOMBER PETER , SCHMIDT CLAUDIA , WEINHARDT CHRISTOF
Published: July 2002

This paper focuses on market-like coordination mechanisms in multi-agent systems, with applications to business planning. Several fundamental criteria are derived in order to evaluate market-like coordination mechanisms. The central criterion is the efficient allocation of jobs to agents. Assuming a relationship between classes of operational planning problems and certain coordination mechanisms, business planning problems are classified on the basis of their relevant attributes. Coordination mechanisms for each of the classes are then introduced on the basis of auction theory and investigated with respect to the trade-off between efficiency and computational tractability. All of the mechanisms prove to have a common basis: the Vickrey Auction.
TOBRAMYCIN ELUTION FROM BONE SUBSTITUTE
Authors: Lawless M. W. , Laughlin R. T. , Kerpsack J. M. , Pisut D.
Published: July 2002

Purpose: To determine the rate of antibiotic elution from tobramycin-impregnated ProOsteon (Interpore) and Collagraft (Zimmer). Methods: Five samples of Collagraft and ProOsteon were impregnated with a solution containing 1.2 g of tobramycin and 10 ml of sterile water. The samples were then allowed to dry overnight. These samples were stored at 37°C in separate test tubes containing phosphate buffered saline (PBS). The solution in each test tube was removed with a pipette at hours 3, 6, 9 and 12 and days 1, 2, 3, 5, 7, 9, 11 and 13. The PBS was then replaced. The pipetted solution was sent for laboratory quantification and also used in a bioassay to determine antibiotic level. To serve as a control, two additional samples of each bone graft that were not impregnated with antibiotic were placed in separate test tubes and subjected to the same protocol. Results: The antibiotic elution rate for both ProOsteon and Collagraft was high at 3 hours [5362 and 4875 μg/ml on day 3 (3.1 μg/ml) for the Collagraft and day 7 (3.7 μg/ml) for the ProOsteon]. Effective intravenous tobramycin level is considered to be 4–6 μg/ml. Conclusion: Bone graft substitute can be used as a delivery vehicle for tobramycin. In addition, antibiotic-impregnated synthetic bone graft may potentially fill a dead space or cavitary defect without the need for large autologous grafts and does not require later removal.
STUDY OF THE HYDROXYAPATITE (HA)-COATED ACETABULAR CUPS RETRIEVED AT REVISION SURGERY — RELATION OF THE RESIDUAL HA TO THE FAILURE ODES
Authors: HU WEN-PIN , LAI KUO-AN , JOU I-MING , LIN JE-HSIN , CHANG GUANG-LIANG
Published: July 2002

Fifty-three retrieved hydroxyapatite (HA)-coated acetabular cups were studied with scanning electron microscope (SEM) for identification of the residual HA. Image processing technique was applied for quantification of the residual HA as percentage of the cup surface. The study included 28 Landos Atoll, 21 Osteonic Omnifit and 4 Howmedica ABG cups. These cups were retrieved at an average of 59.1 (13–107) months after implantation due to aseptic loosening in 24, septic loosening in 14, infection without loosening in 7, polyethylene wear in 7 and osteolysis in 1 cup. The relationships of residual HA to original coating thickness, failure mode, duration in the host and other factors were studied with Pearson's correlation, linear regression and ANOVA tests for its statistical significance.

The residual HA is negatively correlated with the duration in the host (r = -0.375, p < 0.01 for all cups, r = -0.732, p < 0.001 for loose Atoll cups and r = -0.592, p < 0.01 for the loose Omnifit cups). The thicker coating (155 um, Atoll) had more residual HA than the thinner (50 um, Omnifit) coating (p < 0.001). The loose cups had less residual HA than the stable cups (p < 0.001). The loss of HA coating during the first 2 years averages 52% and 22% for the loose and stable Atoll cups, respectively. Thereafter, HA coating disappears at a rate of 7.4 ± 2.6% and 3.8 ± 1.8% per year. And the loss of HA surface from the Omnifit and ABG cups during the first 2 years averages 69% and 42% for the loose and stable cups, respectively. Then the following loss rates are 10.1 ± 3.8% and 7.1 ± 2.9% of surface per year, respectively.

The HA coating is resorbed in the host. The resorption rate is higher on the loose cups than on the stable cups. A hemispherical smooth surfaced cup depends solely on screws for resistance of rotational torque after HA resorption. Clinical loosening and migration of the cup then follow screw loosening or failure. The design of HA-coated acetabular cup should avoid smooth surfaced hemispheric metal shell without a more dependable fixation than screws.
A FILTERING APPROACH TO PRICING IN MULTIFACTOR TERM STRUCTURE MODELS
Authors: GOMBANI ANDREA , RUNGGALDIER WOLFGANG J.
Published: July 2002

We present an approach for the pricing of illiquid bonds (and bond derivatives) in an arbitrage-free way and which is consistent with the observed prices of liquid bonds. The basic model is a multifactor term structure model with abstract latent factors. The approach is based on stochastic filtering techniques, leading to a continuous update of the distribution of the latent factors on the basis of the information coming from the observations. This allows our model to continuously "track" the real market.
EFFECTS OF FOUNDATION STIFFNESS ON VIBRATION BEHAVIOR OF SECONDARY STRUCTURES DUE TO EXTERNAL AND INTERNAL EXCITATIONS
Authors: XIE GUANMO , TANIGUCHI TAKEO
Published: July 2002

In this paper, the vibration behavior of a secondary structure in a frame structure under combined excitations of external earthquake and internal production machinery is investigated. The effects of stiffness of the foundation springs of the primary structure on dynamic behavior of the secondary structure are evaluated. The primary structure is modeled by FEM in which consistent mass and Rayleigh damping matrices are adopted. The secondary structure consists of one mass connected to a beam mounted on a member of the primary structure. Numerical results show that the foundation stiffness has considerable influences on relative displacement response of the secondary structure and provide guidelines for the seismic design of factory buildings with production machinery.
A Day at the Beach: Human Agents Self-Organizing on the Sand Pile
Authors: Ishii Hiroshi , Page Scott E. , Wang Niniane
Published: July 2002

In this paper, we analyze the sand pile model of self-organized criticallity from a social scientific perspective. In the sand pile model, particles of sand land at random locations on a square table and self-organize into a critical state: a conical pile. Thereafter, the size of avalanches satisfies a power law. This empirical fact has led some to claim that self-organizing criticality explains power law distributions that occur in human systems. However, unlike grains of sand, people possess both preferences and the ability to act purposefully given those preferences. We find that by including purposive agents and allowing heterogeneity of purposes, the sand pile need not become critical. We also show that if we allow institutions to moderate actions that we can create any distribution of avalanches.
A NEW CONTROL SCHEME FOR COMBUSTION PROCESSES USING REINFORCEMENT LEARNING BASED ON NEURAL NETWORKS
Authors: STEPHAN V. , DEBES K. , GROSS H.-M. , WINTRICH F. , WINTRICH H.
Published: July 2002

We present a new control scheme for an industrial hard-coal combustion process in a power plant based on reinforcement-learning in combination with neural networks. To comply with the great requirements for environmental protection, the plant operator is interested in a minimization of the nitrogen oxides emission and a maximization of the efficiency factor, while other process parameters have to be kept within predefined limits. To cope with both the tremendous action and state space of the power plant, we present a multiagent-reinforcement-system consisting of 4 agents, which are realized by relatively simple neural function approximators. We demonstrate that our multiagent-system was able to significantly reduce the overall air consumption of the real combustion process of the power plant.
FUNCTIONAL DECOMPOSITION AND ITS APPLICATIONS IN MACHINE LEARNING AND NEURAL NETWORKS
Authors: SELVARAJ H. , SAPIECHA P. , ŁUBA T.
Published: July 2002

In this paper, we will begin with an overview of functional decomposition algorithms based on different graph coloring heuristics. We will then discuss the applications of decomposition strategy for the computer aided design of digital circuits and for the supervised learning of neural networks. While decomposition was used successfully in logic synthesis for several years, its application in the area of neural networks is a novel and promising approach. The computer experiments will show significant benefits in mini mization of silicon space required for digital circuit implementation as well as in reduction of training time for neural networks.
Symbolic Boolean manipulation with ordered binary-decision diagrams
Authors: Bryant Randal E.
Published: July 2002

Ordered Binary-Decision Diagrams (OBDDs) represent Boolean functions as directed acyclic graphs. They form a canonical representation, making testing of functional properties such as satisfiability and equivalence straightforward. A number of operations on Boolean functions can be implemented as graph algorithms on OBDD data structures. Using OBDDs, a wide variety of problems can be solved through
symbolic analysis
. First, the possible variations in system parameters and operating conditions are encoded with Boolean variables. Then the system is evaluated for all variations by a sequence of OBDD operations. Researchers have thus solved a number of problems in digital-system design, finite-state system analysis, artificial intelligence, and mathematical logic. This paper describes the OBDD data structure and surveys a number of applications that have been solved by OBDD-based symbolic analysis.