bluuebunny/crossref_metadata_2025 huggingface dataset:
SLOW BURNING TRANSITION INTO DETONATION IN MoS2−Mg MIXTURE AS A RESULT OF MECHANICAL ALLOYING
Authors: DANIELIAN N. G. , JANAZIAN S. K. , MELNICHENKO V. V. , YENIKOLOPIAN N. S.
Published: November 2004

In this paper the causes and the mechanism of explosion arising in process of molybdenum sulfide ( MoS 2) reduction by mechanical alloying with metallic magnesium (Mg) is investigated. It is shown that mechanical treatment of this reaction results in considerably decreasing the ignition temperature (T ign ) and increasing the burning speed (U burn ). It is assumed that the causes of such T ign and U burn value changes in MoS 2− Mg system is multilayered structure formation.
STRUCTURAL DEPENDENCE OF THE ELECTRONIC STATES OF HIGH-Tc COPPER OXIDES
Authors: OHTA Y. , TOHYAMA T. , MAEKAWA S.
Published: November 2004

A review of the recent developments in the theory of the electronic structure of high-T c copper-oxide compounds is presented. Emphasis is placed on the systematic variations of the electronic properties of the CuO 2 plane for a wide variety of the copper-oxide compounds. Discussions are devoted in particular to the optical charge-transfer gap and superexchange interaction for the undoped insulating states and to the superconducting critical temperature for the doped metallic states. The key physical parameters for the high-T c superconductivity are discussed.
X-RAY INVESTIGATION OF METAL REDUCTION BY MECHANICAL ALLOYING AND SOLID STATE REACTION
Authors: DANIELIAN N. G. , JANAZIAN S. K. , MELNICHENKO V. V.
Published: November 2004

X-ray phase analysis was used for studying the reduction reaction of some metals by mechanicals alloying (MA) and solid state reaction. It is shown that it is possible to obtain both amorphous (Mo, W) and crystalline (Pb) metals as a result of such processes. An assumption is set forth that the amorphous state of metals is stabilized at the expense of the various impurities contained in them.
THE EFFECT OF STRONG ELECTRON-PHONON INTERACTIONS ON THE INFRARED REFLECTANCE IN HIGH-Tc SUPERCONDUCTORS
Authors: TIAN S. Y. , LI M. H. , ZHAO Z. X.
Published: November 2004

We show that the model of charge-transfer fluctuation with LO phonons can unify the interpretation of the infrared features and the phonon softening at about 55 meV measured by neutron scattering experiments in high temperature superconductors. Based upon this model we demonstrate that reflectivity ratio of superconducting state to normal state is strongly modified as a result of strong electron-phonon interaction which is different from Holstein mechanism. A broad peak in the ratio reflectivity develops around the peak position of different neutron phonon density of states. This peak becomes stronger and shifts to a higher frequency as the coupling increases at lower temperatures. This situation complicates the interpretation of the ratio reflectivity peak as the superconducting gap.
A COMPARATIVE STUDY OF RAMAN SPECTRA AND SUPERCONDUCTING CHARACTERISTICS OF 90 K SUPERCONDUCTORS
Authors: LOO B. H. , EMERSON M. T. , WANG N. P. , BURNS D. H. , HUANG C. Y.
Published: November 2004

The Raman spectra and superconducting characteristics of ReBa 2 Cu 3 O 7−x where Re = Y, Nd, Sm, Eu, Gd, Dy and Ho have been studied. We have unambiguously established that the 320- and 500- cm −1 modes, consistently appearing in the 200–800 cm −1 region of the Raman spectra of good quality superconducting Re123 samples with large diamagnetic shielding values, are intrinsically belonged to the Re123 orthorhombic superconducting phase.
EFFECTIVE PROPERTIES OF A DILUTE RANDOM DISTRIBUTION OF SMALL, CONVEX, PERFECTLY CONDUCTING PARTICLES IN A CHIRAL FLUID
Authors: LAKHTAKIA AKHLESH
Published: November 2004

An integral equation method has been used to derive the polarizabilities of an electrically small, perfectly conducting particle of convex shape that is immersed in a chiral fluid. These polarizabilities are then used to obtain the effective electromagnetic/optical properties of a dilute random suspension consisting of such particles in a chiral fluid; the optical activity of the suspension is also estimated.
FERROELECTRIC EPR LINE SPLITTING ABOVE THE TRANSITION TEMPERATURE Tc IN KH2P04
Authors: MESA M. A. , FARACH H. A. , CRESWICK R. J. , POOLE C. P. , MZOUGHI T.
Published: November 2004

EPR studies of As-doped KDP show the presence of quasi-static ferroelectric domains at temperatures well above the ferroelectric transition temperature. The temperature dependence of the separation between the spectral lines from each domain was determined from 10 to 300 K. Comparison were made with mean field theory, and the Anderson exchange model.
LOCALIZED (POLARONIC) CHARGE-TRANSFER EXCITATIONS IN CuO2 LAYERS
Authors: LORENZANA J. , YU L.
Published: November 2004

We show that the recently found polarons and excitons of charge-transfer origin in the 1D p−d model of high temperature superconductors can also occur in 2D. We use a 2D spinless model which is expected to qualitatively describe the charge degrees of freedom of the p−d model in the limit of infinite on-site Coulomb repulsion on both Cu and O. The Cu-O repulsion Upd is treated by an unrestricted Hartree-Fock scheme. We found that in addition to polarons and excitons, other nonlinear excitations like bipolarons and clustering of carriers (phase separation) arise as well. Since the energies of all these excitations are very close to each other at the mean field level, no definite statement can be made about the true ground state.
ONSET OF SCALING BEHAVIOUR IN 2D SLOW CRACKING
Authors: BLUMENFELD RAPHAEL , BALL ROBIN C.
Published: November 2004

We discuss a new mechanism for the onset of scale-invariant sidebranching in quasi-stable cracking of 2D continuous media. We argue that oscillating terms in the stress field lead to nucleation of defects spaced periodically in lnr space, which are unstable and grow into sidebranches. Requiring that the growth rate be slower than the speed of sound defines the range of validity of this analysis. For an isotropic growth we find the marginally stable angle between major arms of the pattern.
X-RAY ANALYSIS OF Si1−xGex/Si SUPERLATTICES
Authors: CUI S.F. , MAI Z.H. , WANG C.Y. , WU L.S. , OUYANG J.T. , LI J.H.
Published: November 2004

We present the studies on the correlation between the structural parameters of the well and the barrier in Si 1−x Ge x/ Si quantum well superlattices by using X-ray grazing incidence diffraction (GID) under total external reflection conditions and the conventional X-ray double-crystal diffraction. Both the coherent growth and the partial relaxed growth in the interfaces between the two components of the superlattices were found by the GID technique. The GID technique gave the valuable information that the relaxation occurs in the interfaces between the two components of the superlattices which cannot be distinguished by other analytical tools. This shows the potential of the depth-controlled analysis for superlattices by the GID technique.
NONLOCAL RESISTANCE AND EDGE CURRENTS IN THE FRACTIONAL QUANTUM HALL REGIME
Authors: WANG J.K. , GOLDMAN V.J.
Published: November 2004

We have studied nonlocal electrical transport over macroscopic distances in the regime of the fractional quantum Hall effect (FQHE). Experiments clearly demonstrate dissipationless edge state conduction associated with the FQHE. Surprisingly, our data imply that there is no edge state conduction near ν=1/2 and on the low ν side of the ν=1 QHE state, while there is edge state conduction near ν=3/2 and on the high ν side of the ν=1 QHE state. We also observe that the electron-hole symmetry is broken for the edge states in a confined geometry. We develop a picture of edge state structure consistent with these observations.
ISOTOPE SHIFT MEASUREMENTS OF HELIUM
Authors: ZHAO PING , LAWALL J.R. , PIPKIN F.M.
Published: November 2004

The helium isotope shift provides invaluable information for testing theories describing many-body systems. We review the recent advances in measurements of the isotope shifts for helium with an emphasis on a new experimental technique.
WEAK MEASUREMENTS
Authors: STORY J.G. , RITCHIE N.W.M. , HULET R.G.
Published: November 2004

A general description of weak measurements is presented. The “weak value” of an operator in pre- and post-selected systems is described both mathematically and using physical arguments. An optical experiment in which a measurement of a weak value has been realized is described. The possible use of pre- and post-selection as a means to amplify and detect weak effects is also discussed.
SUPERCONDUCTING PROPERTIES OF (Tl0.64Bi0.16Pb0.2)Ba2−xSrxCa3Cu4Oy BY LIQUID-GAS-SOLIDIFICATION PROCESSING
Authors: CHOU H. , CHEN H.S. , GYORGY E.M. , KORTAN A.R. , KIMERLING L.C. , THIEL F.A. , Wu M.K.
Published: November 2004

The effect of Sr substitution in (Tl0.64Bi0.16Pb0.2)Ba2−xSrxCa3Cu4Oy(x=0, 1, 2) superconductors is studied by liquid-gas-solidification process. (Tl0.64Bi0.16Pb0.2)Ba2−x SrxCa3Cu4Oy forms a tetragonal structure, with a c axis decreasing with Sr content. The substitution of Sr tends to suppress Cu-O layer formation. It also slows down the phase transformation from Tl-rich to Tl-poor phases which may be attributed to a phase equilibration of kinetic origin. The superconducting crystals grow under non-equilibrium and anisotropic conditions, and exhibit platelet and dentritic morphologies. The resistivity measurements indicate percolation effects with a percolation limit of just above 8% of the high Tc phase.
A CONTINUOUS MODEL OF SURFACE MELTING OF CRYSTAL
Authors: KORNEEV A.A. , TAPINSKAYA O.V. , TRONIN V.N. , TROAIN V.I.
Published: November 2004

It is shown that the existence of a much higher vacancy concentration near the surface of a crystal, results in that the surface melting temperature is decreased. For a wide class of crystals the values of the surface melting temperature is obtained.
THE STUDY OF SCATTERING He FROM Cu(110) WITH A NEW MODEL POTENTIAL
Authors: GÖĞTAS F.
Published: November 2004

The dependence of specular and diffracted probabilities on the incident angle and energy was investigated for He+Cu(110). A new empirical pair potential used in this study gives a good agreement with experimental results.
SUPERCONDUCTING FEATURES IN THE INTEGER QUANTUM HALL EFFECT
Authors: IENGO ROBERTO , LECHNER KURT
Published: November 2004

We construct an effective Action describing the Quantum Hall effect such as to allow for translation invariance and for eigenstates of both energy and total momentum, carrying Hall currents. We show that for integer filling k it entails for the Hall currents the features of a superconductor with carriers’ charge e*=ke, e being the electron’s charge, which could be tested by looking for a.c. Josephson like effects.
AN INVESTIGATION INTO THE OBSERVATION OF WATER ADSORPTION INTO BARBITONE POWDER
Authors: CHAUDHRY M. ASHRAF
Published: November 2004

The adsorption of water in a sample of barbitone has been studied by the dielectric technique over a frequency span between 10 Hz and 100 kHz. It has been found that the adsorbed water only contributes a small component to the dielectric response although the indications are that a large amount of water has been adsorbed. This means that the adsorbed water is in a bound form.
RELATIVISTIC CORRECTIONS TO ELECTRON DWELL TIME IN DOUBLE BARRIER HETEROSTRUCTURES
Authors: CRUZ H.
Published: November 2004

In this work, we have studied relativistic corrections to electron tunneling in double barrier heterostructures through analytical solutions of a Dirac-type equation as effective-mass equation for electrons in the conduction band. It is found that relativistic wave functions for electrons give us small but significant shifts in the electron dwell time obtained through a transfer matrix method of calculation.
THE ENERGY GAP OF THE M3C60 SUPERCONDUCTORS
Authors: ZHANG ZHE , LIEBER CHARLES M.
Published: November 2004

We briefly review tunneling spectroscopy studies of the new fullerene-based superconductors, K 3C60 and Rb 30C60 from our laboratory. At low temperature the reduced energy gap, 2∆/ k Tc, has a value of 5.3 ± 0.2 and 5.2 ± 0.3 for K3C60 and Rb 3 C 60, respectively. The magnitude of the reduced gap for these materials is significantly larger than the value of 3.53 predicted by BCS theory. These results demonstrate that the energy gap scales with Tc and show that the pair coupling interaction is strong in the M 3 C 60 superconductors, and thus they provide information essential to understanding superconductivity in the M 3 C 60 materials.
SYMMETRY OF THE EL2 CENTER IN GaAs
Authors: BAGRAEV N.T.
Published: November 2004

Optical absorption measurements on uniaxially stressed GaAs single crystals point to the C3v symmetry for the D0, D+, and D++ charge states of the EL2 double donor and allow to assign these states respectively to the L, Γ, and X valleys of the conduction band.
ELECTRON TRANSPORT MECHANISM IN COBALT POLYMETHACRYLATE (CoPMA)
Authors: CHOHAN M.H. , KHALID A.H. , ZULFIQAR M. , BUTT P.K. , KHAN FARAH , HUSSAIN RIZWAN
Published: November 2004

Electron transport mechanisms in cobalt polymethacrylate have been investigated. The electrical measurements made on the polymer, show that the current-voltage relationship at lower voltages (V<300 V) is ohmic whereas at higher voltages it is exponential. The strong temperature dependence of current on voltage indicates the dominance of a Poole-Frenkel mechanism and the existence of trapping levels. Low activation energy values suggest an electronic conduction mechanism.
TUNNELING-MEDIATED DISSOCIATION AT METAL SURFACES
Authors: HARRIS J. , Luntz A.C.
Published: November 2004

A summary is given of recent work which demonstrates the role tunneling processes can play in breaking strong chemical bonds when closed-shell molecules strike metal surfaces. With special reference to methane dissociation, it is shown that the recoil of the substrate atoms during the tunnel process influences the tunneling probabilities dramatically, and can produce several orders of magnitude enhancement at elevated surface temperature.
FLUX CREEP IN FLUORINE-DOPING Bi(Pb)-Sr-Ca-Cu-O BULK SUPERCONDUCTOR
Authors: XIAOWEN CAO , SHANGSHEN FENG , XIAOHUI GAO , XIAOLIN WU , HUI YAN , ZHOULAN YIN , QIN WEI
Published: November 2004

We report the field and time dependences of zero field cooled magnetization for fluorine-doped Bi1.7Pb0.3Sr2Ca2Cu3Oy bulk superconductor. By fluorine-doping, the field dependences of both flux creep and pinning potential exhibit some new behaviours suggesting S = dM/d ln t ∝ H1/2 for the field range from H p to 1000 Oe, U0(H)∝ exp (−H/30) for the field below H p and U0(H)∝H−α with α=3/2 for the field above H p .
ONE-LINE RECOGNITION SYSTEM FOR FREE-FORMAT HANDWRITTEN JAPANESE CHARACTERS
Authors: MURASE HIROSHI
Published: November 2004

This paper describes an on-line recognition system for free-format handwritten Japanese character strings which may contain characters with separated constituents or overlapping characters. The recognition method for the system, called candidate lattice method, conducts segmentation and recognition of individual character candidates, and applies linguistic information to determine the most probable character string in order to achieve high recognition rates. Special hardware designed to realize a real-time recognition system is also introduced. The method used on the special hardware attained a segmentation rate of 98.8% and an overall recognition rate of 98.7% for 105 samples.
MOBILE ROBOTS
Authors: THORPE CHARLES E.
Published: November 2004

Mobile robots must deal with unstructured environments in order to be general and useful. Current laboratory robots often use single approach to deal with unstructured environments: position sensing, environment sensing, planning, or mechanical design. Robust robots of the future will have to use combinations of all those approaches, and also handle the difficult problems of system integration. This article is an overview of the problems to be faced and of some of the more promising approaches being investigated.
COMBINED NEURAL-NET/KNOWLEDGE-BASED ADAPTIVE SYSTEMS FOR LARGE SCALE DYNAMIC CONTROL
Authors: HOLDEN ALISTAIR D. C. , SUDDARTH STEVEN C.
Published: November 2004

The control of small-scale systems using either knowledge-based or neural net methods is quite feasible. Large scale systems, however, introduce complexities in modeling and excessive computation time. This paper attacks these difficulties by breaking down the problem into a hierarchy of control contexts. The lowest level of this hierarchy is implemented as rule sets and/or neural networks. A method using "hints" is shown to greatly reduce training time in back-propagation neural nets.
ON THE ASYMPTOTIC PROPERTIES OF RECURRENT NEURAL NETWORKS FOR OPTIMIZATION
Authors: WANG JUN
Published: November 2004

Asymptotic properties of recurrent neural networks for optimization are analyzed. Specifically, asymptotic stability of recurrent neural networks with monotonically time-varying penalty parameters for optimization is proven; sufficient conditions of feasibility and optimality of solutions generated by the recurrent neural networks are characterized. Design methodology of the recurrent neural networks for solving optimization problems is discussed. Operating characteristics of the recurrent neural networks are also presented using illustrative examples.
ON THE RELATIONSHIPS BETWEEN STATISTICAL PATTERN RECOGNITION AND ARTIFICIAL NEURAL NETWORKS
Authors: CHEN C. H.
Published: November 2004

Although statistical pattern recognition and artificial neural networks were initially developed independently, they are now closely related. Such relationships are examined in detail in this paper. Some experimental comparison results are also presented.
ON THE DESIGN OF A TREE CLASSIFIER AND ITS APPLICATON TO SPEECH RECOGNITION
Authors: CHAN CHORKIN , BAO JUN
Published: November 2004

A new algorithm for constructing entropy reduction based decision tree classifier in two steps for large reference-class sets is proposed. The d-dimensional feature space is first mapped onto a line thus allowing a dynamic choice of features and then the resultant linear space is partitioned into two sections while minimizing the average system entropy. Classes of each section, again considered as a collection of references classes in a d-dimensional feature space, can be further split in a similar manner should the collection still be considered excessively large, thus forming a binary decision tree of nodes with overlapping members. The advantage of using such a classifier is that the need to match a test feature vector against all the references exhaustively is avoided. We demonstrate in this paper that discrete syllable recognition with dynamic programming equipped with such a classifier can reduce the recognition time by a factor of 40 to 100. The recognition speed is one third to one half of that using hidden Markov models (HMM), while the recognition rate is somewhat higher. The theory is considerably simpler than that of HMM but the decision tree can occupy a lot of memory space.
MACHINE RECOGNITION AS REPRESENTATION AND SEARCH — A SURVEY
Authors: ZHAO FENG
Published: November 2004

Generality, representation, and control have been the central issues in machine recognition. Model-based recognition is the search for consistent matches of model and image features. We present a comparative framework for the evaluation of different approaches, particularly those of ACRONYM, RAF, and Ikeuchi et al. The strengths and weaknesses of these approaches are discussed and compared, and remedies are suggested. Various trade-offs made in the implementations are analyzed with respect to the systems' intended task domains. The requirements for a versatile recognition system are motivated. Several directions for future research are pointed out.
A SYSTEM FOR THE INTERPRETATION OF 3-D MOVING SCENES FROM 2-D IMAGE SEQUENCES
Authors: MILANO A. , PEROTTI F. , SERPICO S. B. , VERNAZZA G.
Published: November 2004

In this paper, we propose a system aimed at interpreting 3-D scenes from 2-D image sequences in the case of scenes containing solid objects that can be described as being made up of polyhedral subparts. The major problems addressed are the definition of a suitable search strategy to reduce the computational complexity of the problem, and the exploitation of the information provided by motion analysis applied to the image sequence. The object models' representation is based on the definition of view classes. Experimental results on simple real scenes are presented.
IMAGES, OBJECTS, AND SURFACES IN Zn
Authors: VOSS K.
Published: November 2004

An exact analytical approach to n-dimensional discrete images, objects, and surfaces is given. Objects are defined as finite grid point sets of Zn. Using the 2n-neighborhood of Zn, components are maximal connected sets of object points. Formulas are given for count measures of object (points, edges, faces, cells, marginal elements, etc.), and the Euler number ψ(n). Such measures are defined in Z3 with respect to volume, surface content, and the mean curvature integral in E3. The generalization for Zn allows the definition of similarities between n-dimensional objects. The Euler number and other object characteristics can be expressed only by numbers of marginal elements of single object surfaces. Finally, a general formula for ψ(3) is given.
ON ISSUES IN SOFTWARE ENGINEERING AND ARTIFICIAL INTELLIGENCE
Authors: RAMAMOORTHY C. V. , MIGUEL LUIS , SHIM YOUNG-CHUL
Published: November 2004

Software engineering (SE) needs to make substantial breakthroughs in many different areas to allow order of magnitude improvements in software development times, software quality, and system cost. Artificial intelligence (AI) is uniquely positioned to help the SE research community in many of these areas, and we examine issues in AI for SE research.

Given the fuzzy definition of AI, we provide a list of AI techniques to identify how much AI there is in specific AI for SE research. We recommend using the divide and conquer approach for SE automation and provide criteria for dividing the SE problems. We provide a vision of the future CASE environment, a knowledge and database management system at the center in a client-server architecture, and argue that it constitutes an ideal test-bed for research in AI for SE. We recommend an AI for SE research approach that includes dividing the problem up, using protocol analysis, implementing on a realistic CASE environment, and evaluating in industrial settings. We give criteria to evaluate applications of AI to SE including generality, scalability, and combinability. We conclude that AI will help SE to make slow and steady progress, but that it constitutes no silver bullet.
ON THE DEVELOPMENT OF A METHOD TO SYNTHESIZE PROGRAMS FROM REQUIREMENTS SPECIFICATIONS
Authors: COOKE DANIEL E. , GATES ANN
Published: November 2004

This paper reviews the progress that has been made towards the definition of a new generation of computer assisted problem solving tool. When we solve problems with a computer we state the solution in terms of several languages, beginning with a requirements specification language and ending with a program. Beginning with a generalization of a programming language, this paper follows steps towards the removal of control and data structure information in a problem solution. The effort discussed here would result in the requirements specification language being the final language used in problem solving.
SYSTEM DEVELOPMENT AS A WICKED PROBLEM
Authors: YEH RAYMOND T.
Published: November 2004

Many problems in the software industry today result from our ignorance that system development belongs to a class of problems that are "wicked" in nature. This paper discusses key attributes of wicked problems and suggests a basic set of principles based on experiences from good practices in the field to deal with the attributes of wicked problems. As a result of these principles, new process paradigms are needed. Automation of the alternative process and further research on downsizing mainframe applications to distributed applications are also discussed here.
THE ROLE OF PROTOTYPING LANGUAGES IN CASE
Authors: LUQI
Published: November 2004

Prototyping languages form a new category in the computer language family. They are different from the commonly familiar computer languages because they are used to support a higher level of automation at early phases of software development as well as throughout the entire process. They are used to create mechanically processable and executable descriptions or models of proposed software systems. Prototyping languages are also used to firm up requirements via frequent modifications and demonstrations of the models in an iterative process of prototype evolution. The benefits of a prototyping language are fully realized when it is used with its computer-aided prototyping system (CAPS). In this paper, we describe the background, requirements, characteristics, computational features, and general principles for the design of prototyping languages. An example of a prototyping language design is used to illustrate these concepts.
ON THE CHOICE OF THE BEST TEST FOR ATTRIBUTE DEPENDENCY IN PROGRAMS FOR LEARNING FROM EXAMPLES
Authors: GRZYMALA-BUSSE JERZY W. , MITHAL SACHIN
Published: November 2004

The paper discusses a problem associated with learning from examples. Learning programs under consideration, LEM and LERS, were designed to automate knowledge acquisition for expert systems. Hence, both programs induce rules in the minimal discriminant form, i.e., rules based on minimal sets of relevant attributes, called coverings.

The problem addressed in the paper is the selection of the best algorithm for determining coverings. Four different methods, based on indiscernibility relation, partition, characteristic set and lower boundary are compared. Both theoretical analysis and experimental results of multiple running of many sets of examples, with variable number of examples and with variable number of attributes are taken into account. As a result the partition method is determined to be the most efficient way to compute coverings.
THE EXTENDED CONVEX DIFFERENCES TREE (ECDT) REPRESENTATION FOR N-DIMENSIONAL POLYHEDRA
Authors: RAPPOPORT ARI
Published: November 2004

We introduce the Extended Convex Differences Tree (ECDT) representation for n-dimensional polyhedra. The ECDT is simultaneously a representation and an efficiency scheme. A set is represented by a tree. Every node holds a convex bound to the set which it represents (not necessarily the convex hull). The union of the sets represented recursively by the children is the set difference between the parent's convex bound and the set the parent represents. The fact that a node holds a bound to its set is useful for avoidance of unnecessary computations. This bound is convex, permitting efficient algorithms. The ECDT uses convex differences and is therefore able lo look at concave areas as being convex. The ECDT can be viewed as an extension to the Convex Differences Tree scheme, without its drawbacks, or as a restricted form of GSG. We show how Boolean operations are performed directly on the ECDT and how a CSG tree is converted to ECDT form. Various geometric operations on the ECDT are detailed, including point membership classification, slicing by a hyper-plane, and boundary evaluation.
CONSTRUCTING DISCRETE MEDIAL AXIS OF 3-D OBJECTS
Authors: GOLDAK JOHN A. , YU XINHUA , KNIGHT ALAN , DONG LINGXIAN
Published: November 2004

In this paper, an algorithm to construct the approximate medial axis of an object is proposed. The algorithm is based on the Delaunay triangulation of points on the object boundaries. Because the medial axis constructed by this algorithm consists of a set of discrete points, we call it the discrete medial axis. Based on the classification of these discrete points, the structure of the medial axis surfaces of a three-dimensional object are discussed in detail. The correctness of the algorithm is substantiated by a brief theoretical analysis.
COMPUTATIONAL GEOMETRY COLUMN 13
Authors: O'ROURKE JOSEPH
Published: November 2004

Twenty open problems from the Seventh ACM Symposium on Computational Geometry are presented.
DEFORMATION OF N-DIMENSIONAL OBJECTS
Authors: BORREL PAUL , BECHMANN DOMINIQUE
Published: November 2004

This paper presents a new technique for computing space deformations that interpolate a set of user-defined constraints. Constraints are specified by indicating the images of selected points. The deformation is formulated as the product of a polynomial function f of ℝn into a higher-dimensional space, ℝm, with a linear projection from ℝm back to ℝn. The projection matrix is computed using a pseudo-inverse technique. For sufficient m, the degrees of freedom may be used to optimize potential functions controlled by attracting and repulsing points. A prototype implementation is presented, which demonstrates the application of this technique to the interactive design of free-form shapes (when n=3) and of deformation processes in space-time domain (when n=4).
A NEW APPROACH FOR SURFACE INTERSECTION
Authors: MANOCHA DINESH , CANNY JOHN F.
Published: November 2004

Evaluating the intersection of two rational parametric surfaces is a recurring operation in solid modeling. However, surface intersection is not an easy problem and continues to be an active topic of research. The main reason lies in the fact that any good surface intersection technique has to balance three conflicting goals of accuracy, robustness and efficiency. In this paper, we formulate the problems of curve and surface intersections using algebraic sets in a higher dimensional space. Using results from Elimination theory, we project the algebraic set to a lower dimensional space. The projected set can be expressed as a matrix determinant. The matrix itself, rather than its symbolic determinant, is used as the representation for the algebraic set in the lower dimensional space. This is a much more compact and efficient representation. Given such a representation, we perform matrix operations for evaluation and use results from linear algebra for geometric operations on the intersection curve. Most of the operations involve evaluating numeric determinants and computing the rank, kernel and eigenvalues of matrices. The accuracy of such operations can be improved by pivoting or other numerical techniques. We use this representation for inversion operation, computing the intersection of curves and surfaces and tracing the intersection curve of two surfaces in lower dimension.
SERVICE-ORIENTED DESIGN: A MULTI-VIEWPOINT APPROACH
Authors: DIJKMAN REMCO , DUMAS MARLON
Published: November 2004

As the technology associated with the "Web Services" trend gains significant adoption, the need for a corresponding design approach becomes increasingly important. This paper introduces a foundational model for designing (composite) services. The innovation of this model lies in the identification of four interrelated viewpoints (interface behaviour, provider behaviour, choreography, and orchestration) and their formalization from a control-flow perspective in terms of Petri nets. By formally capturing the interrelationships between these viewpoints, the proposal enables the static verification of the consistency of composite services designed in a cooperative and incremental manner. A proof-of-concept simulation and verification tool has been developed to test the possibilities of the proposed model.
CHARACTERIZATION OF PROBABILITY MEASURES THROUGH THE CANONICALLY ASSOCIATED INTERACTING FOCK SPACES
Authors: ACCARDI LUIGI , KUO HUI-HSIUNG , STAN AUREL
Published: November 2004

We continue our program of coding the whole information of a probability measure into a set of commutation relations canonically associated to it by presenting some characterization theorems for the symmetry and factorizability of a probability measure on ℝd in terms of the canonically associated interacting creation, annihilation and number operators.
MODELS FOR THE IRREDUCIBLE REPRESENTATION OF A HEISENBERG GROUP
Authors: DIGERNES TROND , VARADARAJAN V. S.
Published: November 2004

In its most general formulation a quantum kinematical system is described by a Heisenberg group; the "configuration space" in this case corresponds to a maximal isotropic subgroup. We study irreducible models for Heisenberg groups based on compact maximal isotropic subgroups. It is shown that if the Heisenberg group is 2-regular, but the subgroup is not, the "vacuum sector" of the irreducible representation exhibits a fermionic structure. This will be the case, for instance, in a quantum mechanical model based on the 2-adic numbers with a suitably chosen isotropic subgroup.

The formulation in terms of Heisenberg groups allows a uniform treatment of p-adic quantum systems for all primes p, and includes the possibility of treating adelic systems.
LOCAL EXPONENTS AND INFINITESIMAL GENERATORS OF CANONICAL TRANSFORMATIONS ON BOSON FOCK SPACES
Authors: HIROSHIMA F. , ITO K. R.
Published: November 2004

A one-parameter symplectic group {etÂ}t∈ℝ derives proper canonical transformations indexed by t on a Boson–Fock space. It has been known that the unitary operator Ut implementing such a proper canonical transformation gives a projective unitary representation of {etÂ}t∈ℝ on the Boson–Fock space and that Ut can be expressed as a normal-ordered form. We rigorously derive the self-adjoint operator Δ(Â) and a local exponent [Formula: see text] with a real-valued function τÂ(·) such that [Formula: see text].
ON ESTIMATING THE STATE OF A FINITE LEVEL QUANTUM SYSTEM
Authors: PARTHASARATHY K. R.
Published: November 2004

We revisit the problem of mutually unbiased measurements in the context of estimating the unknown state of a d-level quantum system, first studied (in the framework of quantum information) by Wootters and fields7 in 1989 and later investigated by Bandyopadhyay et al.3 in 2001 and Pittenger and Rubin6 in 2003. Our approach is based directly on the Weyl operators in the L2-space over a finite field when d=pr is the power of a prime. When d is not a prime power we sacrifice a bit of optimality and construct a recovery operator for reconstructing the unknown state from the probabilities of elementary events in different measurements.
Physical symptom profiles of depressed and nondepressed patients with cancer
Authors: Chen Mei-Ling , Chang Hsien-Kun
Published: November 2004

Depression and symptom severity are predictive of survival in cancer patients, but are often correlated with each other. This paper compares the physical symptom profiles of depressed and nondepressed cancer patients and further examines the predictive ability of multiple symptoms on depressive status. Data were collected from 121 hospitalized patients with breast, oesophageal and head and neck cancer. Patients were categorized as depressed (n =30) or nondepressed (n =91) using the Hospital Anxiety and Depression Scale. Occurrence of symptoms was evaluated with the Patient Disease Symptom/Sign Assessment Scale. The most prevalent symptom in the total sample was insomnia (occurrence rate=67%). Insomnia, pain, anorexia, fatigue, and wound or pressure sore occurred significantly more often in depressed patients, with no difference in occurrence rates of nausea/vomiting and dyspnoea. Significantly more symptoms were observed in depressed than in nondepressed patients (mean=3.77 versus 2.52). Both groups showed similar rankings of symptom occurrence rates. Patients simultaneously experiencing insomnia, pain, anorexia and fatigue had a higher risk of depression (odds ratio=5.03).
Repeated self‐wounding: Women's recollection of pathways to cutting and of the value of different interventions
Authors: Huband Nick , Tantam Digby
Published: November 2004

Background. More information is needed on the processes that result in self‐wounding and how these are modulated by the selection and delivery of interventions available to those working in non‐specialist settings.

Methods. Ten women participated in a semi‐structured interview where they recalled their experiences of cutting and the helpfulness of specific interventions. Transcripts of these self‐reports were analysed using grounded theory methods.

Results. Having a long‐term relationship with a key worker and being encouraged to express feelings were viewed as the most helpful strategies, whereas relaxation was often reported as making self‐injury worse. The helpfulness of a given intervention was reduced when delivered by someone perceived as underconcerned, overprotective or incompetent. Two pathways to self‐wounding were identified: cutting may result when there is a steady increase of tension until a threshold is reached (the ‘spring’ path), or as a result of the ‘switching on’ of the impulse (the ‘switch’ path). Dissociation during cutting and a craving for cutting were more often associated with switching to the impulse. Different management strategies are called for when the switch path has developed, which appears particularly the case for individuals who have been repeatedly self‐wounding over a substantial period of time.
Helping alliance and ward atmosphere in psychiatric in‐patient care
Authors: Johansson Håkan , Eklund Mona
Published: November 2004

Objective: The study investigated how patients in a psychiatric in‐patient ward perceived the therapeutic relationship and the ward atmosphere, the interrelationships between these phenomena, and whether demographic and clinical factors had an influence on the helping alliance.

Design: This was an explorative study in a natural setting. A correlational and multiple regression design were adopted.

Method: All discharged patients (N = 61) during a limited period completed questionnaires regarding the ward atmosphere and the helping alliance, were rated on psychosocial functioning, and diagnosed according to the ICD‐10.

Results: Several ward‐atmosphere factors correlated with the helping alliance. A multivariate analysis suggested that support, programme clarity, and spontaneity were important ingredients and that support was the most important contributor. Patients with a high level of psychosocial functioning established a better helping alliance and patients with personality disorders tended to develop a weaker helping alliance.

Conclusion: The findings emphasize that a holding environment is important in establishing a good helping alliance, which is consistent with results from the psychotherapy area. Since helping alliance is known to have a most important influence on therapy outcome, one conclusion must be that the staff, in their endeavour to strengthen the supportive element of the ward atmosphere, may improve the therapeutic outcome as well.
Thermodynamic Study of the Second‐Stage Dissociation of N, N‐Bis‐(2‐Hydroxyethyl)Glycine (Bicine) in Water at Different Ionic Strength and Different Solvent Mixtures
Authors: Taha Mohamed
Published: November 2004

The second stage dissociation constant pK2 of N, N‐bis‐(2‐ hydroxyethyl)glycine (bicine) has been determined in aqueous solution at different ionic strengths and different temperatures, using pH‐metric technique. The thermodynamic quantities (ΔG°, ΔH°, and ΔS°) have been studied and discussed. Evaluation of the effect of organic solvent of the medium on the dissociation processes have also been reported and discussed. The organic solvents used were methanol, dimethylsulfoxide (DMSO), and dioxane. The pK2 for the ionization in water +10, +20, +30, +40, and +50 wt % dioxane has been determined at five different temperatures from 15 to 35 °C at intervals of 5 °C. The thermodynamic quantities were calculated. The implications of the results with regard to specific solute‐solvent interactions (particularly stabilization of zwitterionic species) are also discussed.
High‐Content Screening and Profiling of Drug Activity in an Automated Centrosome‐Duplication Assay
Authors: Perlman Zachary E. , Mitchison Timothy J. , Mayer Thomas U.
Published: November 2004

Maintenance of centrosome number is essential for cell‐cycle progression and genomic stability, but investigation of this regulation has been limited by assay difficulty. We present a fully automated image‐based centrosome‐duplication assay that is accurate and robust enough for both careful cell‐biology studies and high‐throughput screening, and employ this assay in a series of chemical‐genetic studies. We observe that a simple cytometric profiling strategy, which is based on organelle size, groups compounds with similar mechanisms of action; this suggests a simple strategy for excluding compounds that undesirably target such activities as protein synthesis and microtubule dynamics. Screening a library of compounds of known activity, we found unexpected effects on centrosome duplication by a number of drugs, most notably isoform‐specific protein kinase C inhibitors and retinoic acid receptor agonists. From a 16 320‐member library of uncharacterized small molecules, we identified five potent centrosome‐duplication inhibitors that do not target microtubule dynamics or protein synthesis. The analysis methodology reported here is directly relevant to studies of centrosome regulation in a variety of systems and is adaptable to a wide range of other biological problems.
Biodegradable packaging life‐cycle assessment
Authors: Bohlmann Gregory M.
Published: November 2004

SRI Consulting's Process Economics Program (PEP) was commissioned by its clients to undertake a life‐cycle assessment (LCA) for the purpose of comparing a biodegradable polymer with a conventional commodity polymer in packaging applications. Biodegradable polymers offer the potential of addressing a wide range of environmental concerns associated with conventional polymers such as greenhouse gas emissions and sustainability. LCA is a tool specifically developed for assessing the overall environmental burden of a product including the system used for manufacturing it and its end‐of‐life treatment.

This paper provides a cradle‐to‐grave LCA of two polymers that may be used in food packaging applications: polylactide (PLA), which is a biodegradable polymer derived from corn; and polypropylene (PP), which is primarily derived from natural gas in the United States. An inventory analysis of the PLA and PP systems is presented. An impact assessment focused on global warming is also provided. Although measured field or facility data are preferred for a rigorous LCA, PEP data can provide a reasonable basis when measured data are unavailable. Energy inventories and greenhouse gas emissions are readily derived from PEP data, but other potentially relevant impact indicators are not. © 2004 American Institute of Chemical Engineers Environ Prog, 2004
Ulysses: a robust, low‐diameter, low‐latency peer‐to‐peer network
Authors: Kumar Abhishek , Merugu Shashidhar , Xu Jun (Jim) , Zegura Ellen W. , Yu Xingxing
Published: November 2004

A number of distributed hash table (DHT)‐based protocols have been proposed to address the issue of scalability in peer‐to‐peer networks. In this paper, we present Ulysses, a peer‐to‐peer network based on the butterfly topology that achieves the theoretical lower bound of logn/log lognon network diameter when the average routing table size at nodes is no more than logn. Compared to existing DHT‐based schemes with similar routing table size, Ulysses reduces the network diameter by a factor of log logn, which is 2–4 for typical configurations. This translates into the same amount of reduction on query latency and average traffic per link/node. In addition, Ulysses maintains the same level of robustness in terms of routing in the face of faults and recovering from graceful/ungraceful joins and departures, as provided by existing DHT‐based schemes. The performance of the protocol has been evaluated using both analysis and simulation. Copyright © 2004 AEI
Pricing vulnerable options in incomplete markets
Authors: Hung Mao‐Wei , Liu Yu‐Hong
Published: November 2004

This paper follows the framework of P. Klein (1996) to price vulnerable options when the market is incomplete. Vulnerable options, which are usually traded in the over‐the‐counter market, may not only face the risk of default but also the risk of illiquidity. Thus, pricing such options under the assumption of market completeness, as was done by H. Johnson and R. Stulz (1987) and P. Klein (1996), seems to be a mistake. Accordingly, the proposed model uses the methodology proposed by J. H. Cochrane and J. Saá‐Requejo (2000) to price vulnerable options under both deterministic and stochastic interest rates in an incomplete market. The model is found to perform well when the interest rate is stochastic. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:135–170, 2005
The terminal nerve and its relation with extrabulbar “olfactory” projections: Lessons from lampreys and lungfishes
Authors: Von Bartheld Christopher S.
Published: November 2004

The definition of the terminal nerve has led to considerable confusion and controversy. This review analyzes the current state of knowledge as well as diverging opinions about the existence, components, and definition of terminal nerves or their components, with emphasis on lampreys and lungfishes. I will argue that the historical terminology regarding this cranial nerve embraces a definition of a terminal nerve that is compatible with its existence in all vertebrate species. This review further summarizes classical and more recent anatomical, developmental, neurochemical, and molecular evidence suggesting that a multitude of terminalis cell types, not only those expressing gonadotropin‐releasing hormone, migrate various distances into the forebrain. This results in numerous morphological and neurochemically distinct phenotypes of neurons, with a continuum spanning from olfactory receptor‐like neurons in the olfactory epithelium to typical large ganglion cells that accompany the classical olfactory projections. These cell bodies may lose their peripheral connections with the olfactory epithelium, and their central projections or cell bodies may enter the forebrain at several locations. Since “olfactory” marker proteins can be expressed in bona fide nervus terminalis cells, so‐called extrabulbar “olfactory” projections may be a collection of disguised nervus terminalis components. If we do not allow this pleiomorphic collection of nerves to be considered within a terminal nerve framework, then the only alternative is to invent a highly species‐ and stage‐specific, and, ultimately, thoroughly confusing nomenclature for neurons and nerve fibers that associate with the olfactory nerve and forebrain. Microsc. Res. Tech. 65:13–24, 2004. © 2004 Wiley‐Liss, Inc.