bluuebunny/crossref_metadata_2025 huggingface dataset:
LATTICE DYNAMICS OF MgO USING THREE-BODY FORCE SHELL MODEL
Authors: MOHAN S. , RADJAKOUMAR T.
Published: November 2004

A modified three-body force shell model is applied to evaluate the phonon dispersion values of MgO. The many-body interaction in the lattice potential is well accounted for by this theory. The values of the phonon frequencies evaluated by this method are in good confirmation with the neutron spectroscopic data.
MICROSTRUCTURAL STUDIES OF SUPERCONDUCTING 3EuBa2Cu3Oy:AgO AND 3GdBa2Cu3Oy:AgO COMPOSITES
Authors: HUANG C.Y. , TAI H.H. , WU M.K.
Published: November 2004

Scanning electron microscopy, energy dispersive X-ray spectroscopy, and polarized light microscopy have shown that the addition of AgO to the E uBa 2 Cu 3 O y and GdBa 2 Cu 3 O y systems results in the growth of very large grains. Distribution of silver particle appears to influence the grain formation and growth in the superconducting composites.
HYDRODYNAMIC RELATIONS IN SUPERCONDUCTIVITY
Authors: GREITER MARTIN , WILCZEK FRANK , WITTEN EDWARD
Published: November 2004

We explore the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of a conserved current. Such a relation holds in models that microscopically contain only one type of charge carrier. We show that such a relation leads to certain universal corrections to the usual effective Lagrangians considered for the description of superfluids. A fully consistent derivation of the superconducting Hall effect predicted by London is given. Some related issues that arise in anyon superconductivity are discussed: the linear Hall effect is derived in a transparent way, and the vanishing of the b term (under appropriate assumptions) is demonstrated formally. Some other possible applications are sketched.
LOW-TEMPERATURE SYNTHESIS OF YBa2Cu3O7−x
Authors: GRISHIN A. M. , MEZIN N. I. , Yu. STAROSTYUK N. , SAMOILENKO Z. A. , PUSHENKO E. I.
Published: November 2004

Technological conditions of evaporation of Y 2 O 3, BaCO 3 and CuO nitrite solutions are found which yield YBa 2 Cu 3 O 7−x as a result of chemical reaction in the course of evaporation. The YBa 2 Cu 3 O 7−x crystalline structure is made more perfect by evaporation cycling. The third evaporation results in formation of 1 × 0.5 × 0.1 mm 3 YBa 2 Cu 3 O 7−x single crystals in dry residue.
THE LAYERED THALLIUM CUPRATES, Tl1+xA2−yLn2Cu2O9: A TRIPLE INTERGROWTH OF THE PEROVSKITE, ROCK SALT AND FLUORITE STRUCTURE
Authors: MARTIN C. , BOURGAULT D. , HERVIEU M. , MICHEL C. , PROVOST J. , RAVEAU B.
Published: November 2004

A new series of layered thallium cuprates — Tl 1.3 Sr 1.6 Pr 2 Cu 2 O 9, Tl 1.3 Ba 1.7 Pr 2 Cu 2 O 9 and Tl 1+x Ba 2−y NdCeCu 2 O 9 — characterized by a mixed valence of thallium Tl(I)-Tl(III) has been synthesized. These compounds crystallize in the tetragonal system (a ≃ 3.9 Å; c ≃ 30 Å). Their structure can be described as an intergrowth of three type of layers: pyramidal layers derived from the perovskite double rock salt-type layers and double fluorite-type layers. These new materials are characterized by a mixed valence of thallium, Tl(III) and T1(I), distributed over two different layers. The study of their electron diffraction patterns shows the existence of satellites like in bismuth and lead cuprates. The incommensurability of the structure, as well as the absence of superconductivity are discussed: a particular attention is drawn to the role of the lone pair cation T1(I) in such properties.
THE TRANSITION TEMPERATURE OF TETRAGONAL TO ORTHORHOMBIC PHASE OF YBa2Cu3Ox
Authors: FAN ZHANGUO , JI CHUNLIN , WUN JUNTAO
Published: November 2004

The tetragonal to orthorhombic phase transition of YBa 2 Cu 3 O x compound was studied at different sintering temperatures and in various oxygen partial pressures by means of the resistivity measurement. The transition temperatures are 680°C, 640°C and 635°C for the oxygen partial pressure of 1 atm, 0.75 atm and 0.21 atm.
GRAVITY AIDED TEXTURE GROWTH IN CERAMIC SUPERCONDUCTORS
Authors: BOURDILLON A. J. , TAN N. X. , SAVVIDES N. , SHARP J.
Published: November 2004

Texture growth in incongruently melting ceramic superconductor materials, such as YBa 2 Cu 3 O 7−x, can be combined with zone refinement in thermal gradients to increase critical current densities. In gravity aided texture growth (GATEG), a vertical thermal gradient is used with downward motion of the partially molten specimen (relative to the furnace) so that the molten phase recrystallizes with grain growth.
THERMAL-NOISE INDUCED RADIO FREQUENCY SUPERRADIANCE IN RESONATOR
Authors: KISELEV Y. F. , SHUMOVSKY A. S. , YUKALOV V. I.
Published: November 2004

This paper deals with a theoretical interpretation of the experiments on detection of radio frequency superradiation in a system of nuclear spins, conducted by the authors previously.1–3 The model Hamiltonian in the pseudospin representation is used for consideration. Dynamic equations are obtained for pseudospin and photon operators with allowance for oscillators of losses and thermal noise. The radiation generating process is shown to go on as follows: thermal noise initiates maser generation that results in a superradiation pulse. The importance of taking account of thermal noise is stressed by numerical estimations.
NUMERICAL CALCULATIONS OF IMAGINARY SUSCEPTIBILITY IN THE INTERGRAIN REGION OF GRANULAR SUPERCONDUCTORS
Authors: BERG PETER , KOZLOWSKI GREGORY
Published: November 2004

Using a critical state model for the intergrain critical current density (J c ) of a granular superconductor in which the grains are separated by Josephson junction type weak links, numerical calculations of the imaginary part of the complex susceptibility (χ″) and the ac losses (W) are performed. The dependences of the imaginary susceptibility on the amplitude of the external magnetic field (Hac), grain size (R g ), barrier width (d), lower critical field (H cl ), normal resistivity of the junction (ρj) and temperature (T) are discussed. We also comment on a minimum in the hysteretic ac losses when a constant magnetic field (Hdc) is superimposed on the alternating field. Some comparison with experimental data is made.
DYNAMICS OF HOLES IN THE Cu-OXIDE SUPERCONDUCTORS
Authors: INOUE J. , MAEKAWA S.
Published: November 2004

Recent developments of our work on the dynamics of holes in strongly correlated electron systems and on the stability of the resonating valence bond state are summarized.
STRUCTURAL INSTABILITY IN A Bi–Sr–Ca–Cu–O SYSTEM
Authors: CHEN XIAOHUA , SHEN HUIMIN , WANG YENING
Published: November 2004

Measurements of internal friction and elastic modulus on Bi–Sr–Ca–Cu–O system reveal that a certain kind of phase transition take place a few tens degrees higher than T c . X-ray diffraction measurements show that the symmetry remains unchanged from room temperature to 77 K but the lattice parameters jump at the transition temperatures. Ferroelastic loop were measured around the temperatures mentioned above, which indicates the existence of movable boundaries and elastic softening. It is considered that the instability favor the superconducting transition followed.
IDENTIFICATION OF PHASES IN Sb-DOPED Bi–Pb–Sr–Ca–Cu–O SYSTEM
Authors: DOU S. X. , SHENG Y. J. , LIU H. K. , SORRELL C. C. , SAVVIDES N.
Published: November 2004

Doping with antimony in the nominal composition Bi 1.8−x Sb x Pb 0.2 Sr 2 Ca 2 Cu 2.8 O 10−y showed that Sb did not substitute for Bi but for Cu. This resulted in a decrease in the Cu 3+ level by exsolution, an increase in the amount of impurities, and a decrease in T0 with increasing amounts of Sb. However, the required reaction time was reduced owing to liquid phase formation. At low Sb levels, the stability of the 110 K phase was found to be oxygen partial pressure dependent; at high Sb levels, the material became an insulator. No indication of T c above 110 K as a result of Sb doping or reduced testing current was observed.
FLUCTUATION EFFECTS AND ANISOTROPY IN UNCONVENTIONAL SUPERCONDUCTORS
Authors: KORUTCHEVA ELKA R. , MILLEV YONKO T.
Published: November 2004

The renormalization group procedure is used to study the interacting-fluctuations regime of an m-component complex order-parameter field with a cubic anisotropy of the type recently discussed group-theoretically in search for an explanation of superconductivity in heavy-fermion systems as well as in high-T c superconductors. The intrinsic magnetic fluctuations are also taken into consideration. The main scaling and the corrections to the scaling laws are completely elucidated. The cross-coupling between the real and the imaginary parts in the cubic term modifies significantly the renormalization-group flow equations in comparison with the real φ4-model with a cubic anisotropy. We find that anisotropy acts to 'stiffen' the first-order character of the transition (the Halperin-Lubensky-Ma effect).
QUANTUM FLUID MECHANICS AND QUANTUM ELECTRODYNAMICS
Authors: WIDOM A. , SRIVASTAVA Y. N.
Published: November 2004

The commutation relations of Landau quantum fluid mechanics are compared with those of quantum electrodynamics. In both cases, the operator representation of the commutators require a macroscopic phase, and a wavefunction periodic in that phase. A physical discussion is given for analogous effects in superfluids and superconductors, with regard to quantum coherence on a macroscopic scale. Other applications are then briefly described.
THEORETICAL ELUCIDATION OF LOCAL MODES IN HIGH-Tc YBaCuVO SUPERCONDUCTORS
Authors: ZHANG MINGSHENG , YIN ZHEN
Published: November 2004

Discrete frequencies caused by extra scattering of impurity atoms in non-ideal solids have been studied by local perturbation theory which elucidates local modes appeared in Raman spectra in V-doped superconducting YBaCuO system. We attribute them to the replacement of copper atoms by lighter vanadium atoms, which provides a positive mass-defective coefficient.
SUPERCONDUCTIVITY OF THE DOPED MOTT INSULATOR IN THE CSL PHASE
Authors: KHVESHCHENKO D. V. , KOGAN Ya. I.
Published: November 2004

The effective infrared theory of the planar CuO 2 antiferromagnetic (AFM) is investigated. In the Chiral Spin Liquid (CSL) phase this theory is the 2 + 1 gauge theory with topological mass (Chern-Simons) term and we obtain the attraction between charged fermions (holes). The last are isodublets as a consequence of the two sublattices existence. We get the gap equations for different waves and there is gap degeneracy between S and P waves. The ground state is P and T odd in the case of the P-wave pairing and there is the new term in the Ginzburg-Landau phenomenological Lagrangian, describing the layer's magnetization.
SHORT RANGE RESONATING VALENCE BOND THEORIES AND SUPERCONDUCTIVITY
Authors: FRADKIN EDUARDO , KIVELSON STEVEN
Published: November 2004

We consider the nature of superconductivity near a spin-liquid state with a large spin-excitation-gap. We argue that the quantum-dimer-model with holes is a good approximation in this limit. The insulator is shown to be exactly equivalent to compact quantum electrodynamics, and has a massive spectrum. The doped system is a superconductor with a low density phase characterized by tightly bound pairs and a high density phase with two weakly coupled condensates.
COHERENT TRANSITION IN A HIGHLY ORIENTED YBa2Cu3O7−δ SUPERCONDUCTING THIN FILM
Authors: WEN H. H. , FANG J. , LU J. H. , CAO X. W. , SHI J. Z. , SHI W. Z. , YAO W. G. , QI Z. Z.
Published: November 2004

The I – V characteristics and critical current density at different temperatures have been carried out with a highly (100) oriented superconducting polycrystalline film. It is found that I c = I c (0)(1 – t)2, which is similar to that of network constructed with ideal SNS junctions. At a temperature T(kT) which is below the individual grains transition temperature T c0 , a coherent transition will occur because the coupling energy between grains begins to be larger than thermal fluctuating energy. According to Halperin-Nelson theory, we estimate that T(kT) = 81.1 K , and the behaviors of temperature dependent resistance can be well explained. Meanwhile, we draw a conclusion that the supercurrent density ρs(T) = ρs(0)(1 − t)2.
THE HALF-FILLED HUBBARD MODEL AND THE 2 + 1 DIMENSIONAL DIRAC LAGRANGIAN
Authors: ANEZIRIS C. , BALACHANDRAN A. P. , SRIVASTAVA A. M.
Published: November 2004

There is a proposal that a 2 + 1 dimensional Lagrangian for an appropriate number of SU(2) doublets of Dirac fields with couplings to an SU(2) gauge field describes the continuum limit of the strongly coupled half-filled Hubbard model. In this paper, we compare the symmetries of these two models and show that the Dirac Lagrangian does have all the symmetries of the latter. In particular, the SU(2) spin rotation symmetry of the latter is shown to be realized as a Pauli-Gürsey symmetry of the Dirac system. The occurrence of the Pauli-Gürsey symmetry in a class of 2 + 1 dimensional Dirac Lagrangians more general than those with SU(2) gauge couplings is pointed out. The Dirac Lagrangian with SU(2) gauge invariance has more symmetries than the half-filled Hubbard system, being in particular Lorentz invariant. Starting with a general ansatz for the continuum Lagrangian and systematically requiring that it fufills the wanted symmetries of the half-filled Hubbard model, a one-parameter family of possible continuum approximations to this model are derived. The Dirac system corresponds to a special value of this parameter. Except for this special case, these approximations are not Lorentz invariant, but they have rotational invariance.
POSITIVE CURVATURE IN PERPENDICULAR CRITICAL FIELD OF HIGH-TEMPERATURE SUPERCONDUCTORS
Authors: LEDVIJ MARKO , DOBROSAVLJEVIĆ-GRUJIĆ LJILJANA
Published: November 2004

The behavior of the perpendicular upper critical field in high T c superconductors is studied theoretically. It is shown, within proximity effect theory, that a substantial deviation from intrinsically linear behavior of [Formula: see text] near T c can occur when imperfections exist in single crystals. A positive curvature arises if there is a competition of superconductivity of two different superconducting phases — the bulk and the defect — in the specimen.
INFLUENCE OF FLUCTUATIONS ON THE LONDON PENETRATION DEPTH
Authors: BUZDIN A. , VUYICHIT B.
Published: November 2004

The fluctuational contribution to London penetration depth λ is calculated. The deviation from usual linear dependence of λ−2 (T) near T c may be observable in single crystals of high T c superconductors.
GUTZWILLER-TYPE WAVE FUNCTIONS FOR CORRELATED FERMIONS
Authors: VOLLHARDT D. , VAN DONGEN P. G. J. , GEBHARD F. , METZNER W.
Published: November 2004

In the last few years significant theoretical progress has been made in our understanding of the physics and quality of Gutzwiller-type variational wave functions for correlated Fermi systems. In particular, new analytic techniques are now available that allow for exact evaluations of expectation values. A brief review of the state-of-the-art is presented.
SERS OF CRYSTAL VIOLET IN SANDBLAST ROUGHENED SILVER SURFACE
Authors: PENG PING , LING KOW-JE , TSE W. S.
Published: November 2004

In this paper we present an alternative way for SERS-active substrate preparation, the sandblast method. The roughened surface prepared by this method is more durable than the silver coated surface which is easily spoiled by moisture. Because the roughness is almost only dependent on the size and the speed of the abrasive, the roughness of the surface can easily be controlled. The abrasives used were 100 μm Al 2 O 3, 52 μm Garnet, 18 μm Garnet, and also 5 μm Garnet. Comparison between the sandblasted and unblasted substrates shows an enhancement factor of ~103. To our knowledge this is the first paper about the SERS-active substrate prepared by this method.
CRITICAL CURRENT AND TRANSITION TEMPERATURE WIDTH IN OXIDE SUPERCONDUCTORS UNDER PRESSURE
Authors: SVISTUNOV V. M. , YU. TARENKOV V. , REVENKO YU. F. , CHERNJAK O. I. , D'YACHENKO A. I. , CISZEK M. , ZALESKI A. J.
Published: November 2004

The critical current density of Y-based and Bi-based high-T c superconductors has been measured under pressure. The substantial increase of j c with pressure is found. The results of our measurements can be explained if the sample is regarded as a network of S-N-S junctions with arbitrary parameters. These junctions can be formed by integrain layers and/or twin boundaries.
VARIATIONAL PRINCIPLES OF NON-EQUILIBRIUM THERMODYNAMICS AND KINETICS OF RELAXATION TO THE EQUILIBRIUM OF FLUCTUATING MACROSCOPIC SYSTEMS
Authors: DEVYATKO YU. M. , TRONIN V. N.
Published: November 2004

On the strength of variational principles of non-equilibrium thermodynamics we have proposed a non-perturbative approach which permits determination of the most probable trajectory of motion of fluctuating macroscopic systems.
FORMATION OF THE "2223" SUPERCONDUCTING PHASE IN Bi4−xPbxSr3Ca3Cu4O16 SUPERCONDUCTORS
Authors: TANG I. M. , EAIPRASERTSAK K. , CHITAREE R.
Published: November 2004

Formation of the "2223" superconducting phase in Pb doped Bi 4 Sr 3 Ca 3 Cu 4 O 16 superconductor is studied. The X-ray diffraction patterns of the Bi 4−x Pb x Sr 3 Ca 3 Cu 4 O 16 (0.7 < x < 1.2) superconductors formed by various heat treatments indicate that they are all multiphase systems containing both the high T c and low T c superconductors, with the volume fraction of the "2223" phase increasing with increased Pb content. The high temperature component have extrapolated T c 's of around 105 K. The zero resistivity temperature decrease with lead content but are well above the reported T c (75 K) of the Pb free host superconductor.
THE NEMATIC-SMECTIC-A-SMECTIC-C MULTICRITICAL POINT IN BINARY LIQUID-CRYSTAL MIXTURES
Authors: QIU RUOZI , HO JOHN T.
Published: November 2004

Properties near the nematic-smectic-A-smectic-C multicritical point present in binary liquid-crystal mixtures are reviewed. Recent dynamic Fréedericksz deformation and quasielastic light-scattering results are described and their relationship with data from X-ray scattering and static light scattering is discussed.
CALCULATED DIELECTRIC PARAMETERS OF BARIUM TITANATE-POTASSIUM TANTALATE COMPOSITES AS A FUNCTION OF COMPOSITION AND FREQUENCY
Authors: SARKAR S.K.
Published: November 2004

Some dielectric parameters such as dielectric constant, resistivity, dielectric strength, loss tangent, saturation polarisation, coercive field of barium titanate-potassium tantalate composites have been calculated as a function of composition and frequency, assuming a very simplified model and a 3–0 connectivity pattern. Most of the parameters have been found to vary linearly with composition at a given frequency.
HUME-ROTHERY PHASES AND QUANTUM HETEROGENEOUS SYSTEMS
Authors: MARKIEWICZ R.S.
Published: November 2004

A recently introduced model of quantum heterogeneous phases is extended to include the effects of coupling between impurities and charged domains. A discussion is given about the application of this model to several physical problems, including Hume-Rothery phases, localization, and quasicrystals.
HOLE-PAIR CONDENSATION AND EFFECTIVE FIELD THEORY OF THE HUBBARD MODEL
Authors: ICHINOSE IKUO , MATSUI TETSUO
Published: November 2004

We present a microscopic derivation of a low-energy effective field theory of the Hubbard model with strong Coulomb repulsion (the t-J model) in the superconducting phase. It is a U(1) gauge theory consisting of the CP1 sigma model for spins plus a relativistic Dirac theory for doped holes. A coherent condensation of bilocal field for the nearest neighbor hole-pairs is assumed to take place in a “flux” phase. Fluctuations of phases of hole-pairs are stabilized by a new Higgs mechanism. The normal state is a fermi liquid coupled with the CP1 gauge field.
SELF-CONSISTENT RENORMALIZATION OF THE TOPOLOGICALLY MASSIVE (2+1) DIMENSIONAL CHERN-SIMONS THEORY AND CORRELATIONS IN ANYON SYSTEM
Authors: KHVESHCHENKO D.V. , KOGAN Y.I.
Published: November 2004

Chern-Simons term renormalization in a topologically massive electrodynamics is studied at a finite density of particles. It follows from a self-consistent calculation that the renormalized coefficient of the Chern-Simons term is only two times smaller than the bare one and does not vanish identically. It is shown that a statistical transmutation has a two-stage character in a finite density system.
THIN ZIRCONIUM DIOXIDE AND YTTRIUM OXIDE-STABILIZED ZIRCONIUM DIOXIDE FILMS PREPARED BY PLASMA-CVD
Authors: WENDEL H. , HOLZSCHUH H. , SUHR H. , ERKER G. , DEHNICKE S. , MENA M.
Published: November 2004

Thin zirconia (zirconium dioxide) films are deposited by PECVD using as precursors organometallic compounds, metal alkoxides, and metal β-diketonates. The properties of the films depend on the substrate temperature, power density and the nature and partial pressure of the precursor. Thin films of zirconia stabilized with yttria (yttrium oxide) are formed at relatively low deposition temperatures (500°C) using the β-diketones of zirconium and yttrium.
REFLECTANCE OF RBa2Cu3O7−δ CERAMIC SUPERCONDUCTORS
Authors: MEMON A. , KHAN M.N. , PORTER C.D. , TANNER D.B.
Published: November 2004

Infrared and far-infrared reflectance spectra have been measured for RBa 2 Cu 3 O 7−δ ceramic superconductors (R=Y, Gd, Eu, and Yb). The spectra consist of a broad mid-infrared band with vibrational features superimposed. One phonon mode — attributed to the c-axis vibration of R — shows a substantial decrease in frequency on substitution of Y with heavier rare earths. Other phonons show only small shifts.
UNIVERSALITY IN DIFFUSION OF CLASSICAL ADATOMS ON SURFACES
Authors: ALA-NISSILA T. , YING S.C.
Published: November 2004

We describe results obtained from a novel microscopic theory of diffusion of classical adatoms on surfaces.
IONIC AND MIXED CONDUCTIONS IN Ag PHOTODOPING PROCESS
Authors: TANAKA K.
Published: November 2004

The recent progress in resolving the mechanism of the Ag photodoping phenomenon in chalcogenide glasses is reviewed. The study of the photodoping kinetics in Ag/As-S system under hydrostatic pressure to 100 kbar suggests that ionic and/or mixed conductions are responsible for the phenomenon.
A THERMODYNAMIC APPROACH TO STRETCHED EXPONENTIAL RELAXATION
Authors: TAGLIAFERRO A.
Published: November 2004

In this paper a model that, starting from the concept of “freezing” of a structure, naturally leads to the understanding of the stretched exponential relaxation in an out of equilibrium system is presented.
STATISTICAL PATTERN RECOGNITION — EARLY DEVELOPMENT AND RECENT PROGRESS
Authors: CHEN C. H.
Published: November 2004

The area of statistical pattern recognition has experienced about three decades of continued progress. In this paper, early development of the area is examined by reviewing the activities of the first decade. Recent progress in major topics of statistical pattern recognition including classification rules, feature extraction, contextual analysis and cluster analysis, are then reviewed. Particular notes are made on the important contributions of the late Prof. Fu, which have profound impact on the development of statistical pattern recognition. The future outlook of the area is indeed bright as many applications making use of statistical pattern recognition are explored to seek more reliable recognition performance. Efforts on efficient hardware implementation and less costly recognition software packages as well as the combined statistical-structural approach are also likely to increase significantly.
RECOGNIZING UNEXPECTED OBJECTS: A PROPOSED APPROACH
Authors: ROSENFELD AZRIEL
Published: November 2004

Humans can recognize familiar, but unexpected objects, belonging to highly variable object classes, in a fraction of a second — a few hundred cycles of the neural visual "hardware". This position paper suggests computational techniques that could serve as a basis for this type of object recognition if implemented on appropriate parallel hardware.
AN APPROXIMATE LINEAR TIME PROPAGATE AND DIVIDE THEOREM PROVER FOR PROPOSITIONAL LOGIC
Authors: HARALICK ROBERT M. , WU SHEAU-HUEI
Published: November 2004

For theorem proving in the propositional calculus, we describe a semantic non-resolution based propagate and divide algorithm using the three principles of: reducing a potential theorem size by appropriate substitutions and simplifications; minimizing tree branching by using matching to carry out complete constraint propagation; and choosing alternatives which efficiently solve the subproblem currently being worked on. We provide experimental evidence based on almost 240,000 experiments indicating that this propagate and divide algorithm needs, on the average, approximately a linear amount of computation time as a function of problem size (length of well-formed formula) to prove a theorem in the propositional calculus. Furthermore, the computation time seems to depend only on the length of the well-formed formula and not on the number of distinct atoms in the well-formed formula.
AN ALGORITHM FOR LOGICALLY DEDUCING HORN CLAUSES AND PROCESSING LOGIC QUERIES
Authors: YANG CHAO-CHIH
Published: November 2004

This paper shows that many production rules in a rule based system and some functional dependencies in a relational database can be transformed into Horn clauses. This paper also develops an algorithm for constructing a more general deduction graph that is extended from the algorithm in Ref. 12, originally designed for finding a subset of functional dependencies, which logically deduces a functional dependency not in the subset. Since a relational database is a special case of a logic program5, many existing techniques in the area of relational databases can be extended and then used in logic programming and particularly in the Horn clause logic queries without relying on the resolution-refutation theorem-proving method in artifical intelligence. By using this new graphical method, there are several advantages as compared with the standard PROLOG implementation.
USING KNOWLEDGE IN SIGNAL INTERPRETATION
Authors: FAURE CLAUDIE
Published: November 2004

When Pattern Recognition is aimed at human task automatization, such as the interpretation of visual data, it leads to Knowledge-Based Pattern Recognition (KBPR) systems. The design of a system, which contains a mixture of human knowledge and numerical data treatments, implies some tasks like Knowledge Acquisition (KA), dividing a problem into sub-problems or identifying different perceptual functions. Such problems cannot be solved by pure PR methods. Improvement of performances in KBPR systems is achieved through a better understanding of the cognitive processes which are involved during data interpretation and introspection which provides thinking aloud data. This paper will focus on problems concerned with knowledge as they are encountered in the design of expert systems for visual data interpretation. KA is considered as a necessary task for the system designer. Useful information is collected from the expert, however KA cannot provide a complete description of the human recognition process, directly usable for automatic numerical data interpretation. Verbal descriptions are lacking when introspection cannot reveal cognitive states such as those, for example, where perceptual adaptation is activated. The acquired knowledge consists of verbal descriptions as well as non-verbal knowledge provided by the analysis of the expert in action. The combination of acquired human knowledge and numerical data treatments is illustrated through examples where low level interpretation is achieved on task-adapted data representations. The need to design intermediate tools for making the dialogue more efficient or to define operational data representations is emphasized.
APHODEX, AN ACOUSTIC-PHONETIC DECODING EXPERT SYSTEM
Authors: CARBONELL NOËLLE , FOHR DOMINIQUE , HATON JEAN-PAUL
Published: November 2004

The acoustic-phonetic decoding of sentences is a major bottleneck in continuous speech recognition. Our group has been working in this area for the past twelve years. In order to improve the accuracy of present phonetic decoders, we are now developing an expert system called APHODEX that should emulate the competence of an experienced spectrogram reader. After a brief description of the methodology used to elucidate the expert's knowledge and strategies, we focus on the expert's approach and results. Finally we explain how this expertise has been implemented; some results from the present experimental version of our system are given.
AN OPTIMAL REGION GROWING ALGORITHM FOR IMAGE SEGMENTATION
Authors: MONGA OLIVIER
Published: November 2004

We present a new approach to the segmentation problem by optimizing a criterion which estimates the quality of a segmentation. We use a graph-based description of a partition of an image and a merging strategy based on the optimal use of a sequence of criteria. This method separates the strategy of making use of the segmentation criteria from their definition. An efficient data structure enables our implementation to have a low algorithmic complexity. Our method offers a general framework for solving a large class of segmentation problems. We show how to adapt this method to segment 2-D natural images including color images. This algorithm is also used for segmentation of 3-D images.
A KNOWLEDGE-BASED CHINESE LETTER-WRITER
Authors: TZU KOH TOH
Published: November 2004

Since the end of last year, the researchers at the Institute of Systems Science (ISS) started to consider a more ambitious project as part of its multilingual programming objective. This project examines the domain of Chinese Business Letter Writing. With the problem defined as generating Chinese letters to meet business needs, investigations suggest an intersection of 3 possible approaches: knowledge engineering, form processing and natural language processing. This paper attempts to report some of the findings and document the design and implementation issues that have arisen and been tackled as prototyping work progresses.
RECOGNITION OF LEXICAL TONES FOR ISOLATED SYLLABLES AND DISYLLABLES IN MANDARIN SPEECH
Authors: YANG WU-JI , LEE JYH-CHYANG , CHANG YUEH-CHIN , WANG HSIAO-CHUAN
Published: November 2004

This study purposes a method for recognizing the lexical tones in Mandarin speech. The method is based on Vector Quantization (VQ) and Hidden Markov Models (HMM). The pitch periods are extracted to derive the feature vectors which represent pitch height and pitch contour slope. One HMM is trained by the feature vectors of monosyllables for each tone. Then the HMMs are used to recognize the tone of monosyllables and disyllables. For the monosyllables, the accuracy rate can be 93.75% for speaker-independent cases. For the disyllables, the accuracy rates are 93% for the first syllables and 90% for the second syllables. It shows that the tone of the second syllable may be affected by the preceding syllable. This degradation also reveals the fact of tone variation in Mandarin speech.
A SYSTEM FOR ON-LINE RECOGNITION OF CHINESE CHARACTERS
Authors: CHEN KEH-JIANN , LI KUO-CHUN , CHANG YEONG-LONG
Published: November 2004

The target of this recognition system is the set of handwritten Chinese characters input from tablet devices with stroke-sequence and stroke-count being free but within the constraint of normal writing.

A formalism based upon an initial stroke-sequence decision tree and position matching has been developed for recognizing handwritten Chinese characters. This formalism has the advantages of using the features of strokes, stroke-sequence, and geometric relations but avoids the disadvantages caused by the instability of all of the above features. With extensive training, it can be proven that this formalism may provide a very promising result even in handling erroneous writing such as missing a stroke, wrong writing sequence etc.
KNOWLEDGE PATTERN REPRESENTATION OF CHINESE CHARACTERS
Authors: WANG PATRICK SHEN-PEI
Published: November 2004

This article discusses some intelligence aspects of Chinese characters. Some basic concepts of two-dimensional pattern representation and artificial intelligence such as semantic networks, forward chaining, deduction and the resolution principle are used to analyze and interpret the syntactic structure, representation, semantics and evolution of Chinese characters. The concept of degrees of ambiguity and the principle of new characters are investigated. It is found that Chinese characters are actually not only artistically elegant and culturally rich but also semantically meaningful and intelligently sound. Finally some topics for future research such as intelligent pattern recognition for Chinese characters, automatic learning and translation, and knowledge-based Chinese language understanding are discussed.
THE SIL-ICON COMPILER—AN ICON-ORIENTED SYSTEM GENERATOR
Authors: CHANG SHI-KUO , TAUBER MICHAEL J. , YU BING , YU JING-SHENG
Published: November 2004

The SIL-ICON Compiler is a software system for the specification, interpretation, prototyping and generation of icon-oriented systems. In this paper, the design of the SIL-ICON Compiler is described. An application example to design a text editor using the Heidelberg Icon Set is presented in detail.
LOCATION PARAMETER ESTIMATION OF A MULTISPECTRAL SAMPLE BY A MEDIAN OPERATION
Authors: POMALAZA-RÁEZ CARLOS A. , FONG YU-SHAN
Published: November 2004

Three different kinds of median type estimators for use in applications where the underlying probability distributions are multivariate are proposed and analyzed. The numerical complexity and the statistical characteristics of the estimators are studied and discussed. Numerical results give evidence that the estimator which is a simple extension of the scalar median has an overall performance that is the same or better than the other two proposed estimators.
PROGRESS IN HIGH COMPRESSION IMAGE CODING
Authors: KUNT MURAT
Published: November 2004

The digital representation of an image requires a very large number of bits. The goal of image coding is to reduce this number, as much as possible, and to reconstruct a faithful duplicate of the original picture. Early efforts in image coding, solely guided by information theory, led to a plethora of methods. The compression ratio reached a plateau around 10: 1 a couple of years ago. Recent progress in the study of the brain mechanism of vision and scene analysis has opened new vistas in picture coding. Directional sensitivity of the neurones in the visual pathway combined with the separate processing of contours and textures has led to a new class of coding methods capable of achieving compression ratios as high as 100: 1. This paper presents recent progress on some of the main avenues of object-based methods. These second generation techniques make use of contour-texture modeling, new results in neurophysiology and psychophisics and scene analysis.
MULTIFONT CHARACTER RECOGNITION FOR TYPESET DOCUMENTS
Authors: SHLIEN SEYMOUR
Published: November 2004

An optical character reader for processing typeset documents must be able to handle proportional spacing, the presence of touching characters and a wide variety of type fonts. This paper describes the design of a multifont character recognizer which uses a binary decision tree to classify a character on the basis of 197 geometric features. The algorithm for designing the decision tree is based upon an entropy minimization procedure, and makes no assumptions on the distribution or independence of the binary features.

The decision tree classifier provides confidence measures which may be used to reduce the substitution error rate at the expense of higher rejection rates. Methods of reducing the overall error rate by combining the decision tree classifier with other classifiers were examined. In particular, the paper evaluates the performance of a classifier using a combination of multiple decision trees, template matching and contextual post-processing. Error rates were highly sensitive to typeface and varied between 10 percent and 0.1 percent. Computer processing times for the various stages of the system are presented.
SPATIAL KNOWLEDGE REPRESENTATION
Authors: SRIHARI SARGUR N. , XIANG ZHIGANG
Published: November 2004

The use of spatial knowledge is necessary in a variety of artificial intelligence and expert systems applications. The need is not only in tasks with spatial goals such as image interpretation and robot motion, but also in tasks not involving spatial goals, e.g. diagnosis and language understanding. The paper discusses methods of representing spatial knowledge, with particular focus on the broad categories known as analogical and propositional representations. The problem of neurological localization is considered in some detail as an example of intelligent problem-solving that requires the use of spatial knowledge. Several solutions for the problem are presented: the first uses an analogical representation only, the second uses a propositional representation and the third uses an integrated representation. Conclusions about the different representations for building intelligent systems are drawn.
A COMBINATION OF STRATEGIES FOR PARSING GRAMMATICAL AGREEMENT IN HINDI
Authors: DEY PRADIP , HAYASHI YOICHI , BATTISTELLA EDWIN L.
Published: November 2004

Hindi exhibits an obligatory grammatical agreement pattern (subject-verb, object-verb, or neutral agreement), and any adequate parser must reject or mark strings that violate grammatical agreement. We develop a combination of strategies for parsing grammatical agreement in Hindi and implement them in an Augmented Transition Network (ATN) parser. It is shown that semantic information is required to parse grammatical agreement in Hindi.
A KNOWLEDGE-BASED SYSTEM FOR THE IMAGE CORRESPONDENCE PROBLEM
Authors: LEE CHUNG-MONG , PONG TING-CHUEN , SLAGLE JAMES R.
Published: November 2004

The image correspondence problem has generally been considered the most difficult step in both stereo and temporal vision. Most existing approaches match area features or linear features extracted from an image pair. The approach described in this paper is novel in that it uses an expert system shell to develop an image correspondence knowledge-based system for the general image correspondence problem. The knowledge it uses consists of both physical properties and spatial relationships of the edges and regions in images for every edge or region matching. A computation network is used to represent this knowledge. It allows the computation of the likelihood of matching two edges or regions with logical and heuristic operators. Heuristics for determining the correspondences between image features and the problem of handling missing information will be discussed. The values of the individual matching results are used to direct the traversal and pruning of the global matching process. The problem of parallelizing the entire process will be discussed. Experimental results on real-world images show that all matching edges and regions have been identified correctly.
INTEGRATING LOW-LEVEL FEATURES COMPUTATION WITH INDUCTIVE LEARNING TECHNIQUES FOR TEXTURE RECOGNITION
Authors: PACHOWICZ PETER W.
Published: November 2004

This paper presents a method for applying inductive learning techniques to texture description and recognition. Local features of texture are computed by two well-known methods, Laws’ masks and co-occurrence matrices. Then, a three-level generalization of local features is applied to create texture description rules. The first level generalization, the scaling interface, has been implemented to transform the numeric data of local texture features into their higher symbolic representation as numerical ranges. This scaling interface tests data consistency as well. The creation of description rules incorporating the inductive incremental learning algorithm is the second generalization step. The SG-TRUNC method of rule reduction is applied as the next hierarchical generalization level. This machine learning approach to texture description and recognition is compared with the classic pattern recognition methodology. The results from the recognition phase are presented from six classes of textures, characterized by smoothly changing illumination and/or texture resolution. The average recognition rate was 91% for the inductive learning approach, and all classes of textures were recognized. In comparison, the traditional k-NN pattern recognition method did not recognize one class of texture, and the average recognition rate was 83%. The proposed methodology smooths the recognition rates through the hierarchy of generalization levels, i.e. the next generalization step increases these rates for classes that were less easily recognized, and decreases these rates for classes that were more easily recognized.
QUERYING AN OBJECT-ORIENTED DATABASE USING FREE LANGUAGE
Authors: TRIGANO PHILIPPE , BARTHES JEAN-PAUL , GREBOVAL CATHERINE , VALLERNAUD FRANÇOIS
Published: November 2004

A man-machine interface in natural language for a DataBase Management System (DBMS) called VORAS, based upon semantics, is presented. This DBMS can also be used for knowledge representation, and is well-suited to the design of queries in natural language. The system VORAS is an object-oriented DBMS developed from a specific model of representation called the Property Driven Model (PDM). A user may write a query in natural language. Most of the analysis is done at a semantic level. A syntactic level has been added, to improve the performance of the system. However, it is still possible to use a short-hand style.
PRIOPS: A REAL-TIME PRODUCTION SYSTEM ARCHITECTURE FOR PROGRAMMING AND LEARNING IN EMBEDDED SYSTEMS
Authors: PARSON DALE E. , BLANK GLENN D.
Published: November 2004

The Prioritized Production System (PRIOPS) is an architecture that supports time-constrained, knowledge-based embedded system programming and learning. Inspired by the theory of automatic and controlled human information processing in cognitive psychology, PRIOPS supports a two-tiered processing approach. The automatic partition provides for compilation of productions into constant-time-constrained processes for reaction to environmental conditions. The notion of a habit in humans approximates the concept of automatic processing trading flexibility and generality for efficiency and predictability in dealing with expected environmental situations. Explicit priorities allow critical automatic activities to pre-empt and defer execution of lower priority processing. An augmented version of the Rete match algorithm implements O(1), priority-scheduled automatic matching. The controlled partition supports more complex, less predictable activities such as problem solving, planning, and learning that apply in novel situations for which automatic reactions do not exist. The PRIOPS notation allows the programmer of knowledge-based embedded systems to work at a more appropriate level of abstraction than is provided by conventional embedded system programming techniques. This paper explores programming and learning in PRIOPS in the context of a maze traversal program.
RECOGNITION OF PARTIAL PLANAR SHAPES IN LIMITED MEMORY ENVIRONMENTS
Authors: CHAUDHURY SANTANU , SUBRAMANIAN S. , PARTHASARATHY GUTURU
Published: November 2004

Industrial vision systems should be capable of recognising noisy objects, partially occluded objects and randomly located and/or oriented objects. This paper considers the problem of recognition of partially occluded planar shapes using contour segment-based features. None of the techniques suggested in the literature for solving the above problem guarantee reliable results for problem instances which require memory in excess of what is available. In this paper, a heuristic search-based recognition algorithm is presented, which guarantees reliable recognition results even when memory is limited. This algorithm identifies an object, the maximum portion of whose contour is visible in a conglomerate of objects. For increasing efficiency of the method, a two-stage recognition scheme has been designed. In the first phase, a relevant subset of the known model shapes is chosen and in the second stage, matching between the unknown shape and elements of the relevant subset is attempted using the above approach. The technique is general in the sense that it can be used with any kind of contour features. To evaluate the efficiency of the method, experimentation was carried out using polygonal approximations of the object contours. Results are cited for establishing the effectiveness of the approach.
Dissociative Disorders
Authors: Kihlstrom John F.
Published: November 2004

The dissociative disorders, including “psychogenic” or “functional” amnesia, fugue, dissociative identity disorder (DID, also known as multiple personality disorder), and depersonalization disorder, were once classified, along with conversion disorder, as forms of hysteria. The 1970s witnessed an “epidemic” of dissociative disorder, particularly DID, which may have reflected enthusiasm for the diagnosis more than its actual prevalence. Traditionally, the dissociative disorders have been attributed to trauma and other psychological stress, but the existing evidence favoring this hypothesis is plagued by poor methodology. Prospective studies of traumatized individuals reveal no convincing cases of amnesia not attributable to brain insult, injury, or disease. Treatment generally involves recovering and working through ostensibly repressed or dissociated memories of trauma; at present, there are few quantitative or controlled outcome studies. Experimental studies are few in number and have focused largely on state-dependent and implicit memory. Depersonalization disorder may be in line for the next “epidemic” of dissociation.
THE NOD MOUSE: A Model of Immune Dysregulation
Authors: Anderson Mark S. , Bluestone Jeffrey A.
Published: November 2004

▪ Abstract  Autoimmunity is a complex process that likely results from the summation of multiple defective tolerance mechanisms. The NOD mouse strain is an excellent model of autoimmune disease and an important tool for dissecting tolerance mechanisms. The strength of this mouse strain is that it develops spontaneous autoimmune diabetes, which shares many similarities to autoimmune or type 1a diabetes (T1D) in human subjects, including the presence of pancreas-specific autoantibodies, autoreactive CD4+and CD8+T cells, and genetic linkage to disease syntenic to that found in humans. During the past ten years, investigators have used a wide variety of tools to study these mice, including immunological reagents and transgenic and knockout strains; these tools have tremendously enhanced the study of the fundamental disease mechanisms. In addition, investigators have recently developed a number of therapeutic interventions in this animal model that have now been translated into human therapies. In this review, we summarize many of the important features of disease development and progression in the NOD strain, emphasizing the role of central and peripheral tolerance mechanisms that affect diabetes in these mice. The information gained from this highly relevant model of human disease will lead to potential therapies that may alter the development of the disease and its progression in patients with T1D.