bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of thaw weakening in pavement stiffness using the spectral analysis of surface waves
Authors: Storme Maud , Konrad Jean-Marie , Fortier Richard
Published: July 2004

Mechanistic methods for the design of pavement structure in cold regions require an adequate knowledge of the seasonal variations in elastic properties of the structural layers. In this study, the spectral analysis of surface waves (SASW) method was adopted to monitor the changes of the stiffness modulus in pavement during a complete freezethaw cycle. The SASW tests were performed on a section of pavement in Québec City over a complete freezethaw cycle in 2001. The stiffness profiles of the pavement layers were back-calculated from the experimental dispersion curves using a forward-modelling approach based on a discrete stiffness matrix method. The seasonal variations in stiffness in the base, subbase, and subgrade were then assessed. The thaw-weakening period and the recovery in stiffness after the complete thaw were observed. The minimum value of the stiffness modulus in the base layer was about 80% of its prefreezing value, and those of the subbase and subgrade were about 60%. A sharp change in the back-calculated moduli at temperatures close to the freezing point was observed. The relevance of using the SASW method to study the thaw weakening and recovery in pavement stiffness affected by freezethaw cycles is clearly shown in this study.Key words: SASW, pavement, seasonal variation, stiffness, thawing, recovery.
Swelling pressures of compacted bentonites from diffuse double layer theory
Authors: Tripathy Snehasis , Sridharan Asuri , Schanz Tom
Published: July 2004

The swelling pressures of several compacted bentonites (MX80, Febex, and Montigel) proposed for use as barrier materials in storing high-level radioactive waste in many countries were determined from the GouyChapman diffuse double layer theory. The swelling pressures thus determined were compared with the reported experimental swelling pressures. The study revealed that, in general, at low compaction dry densities of the bentonites, the experimental swelling pressures are less than their theoretical counterparts, with the reverse trend at high compaction dry densities. Based on the reported experimental results for the three bentonites, relationships between the nondimensional midplane potential function, u, and the nondimensional distance function, Kd, were established. New equations for the swelling pressure were proposed on the basis of the diffuse double layer theory and the reported experimental data to compute swelling pressures of compacted bentonites. The suitability of the new equations was also verified with additionally reported experimental swelling pressures from three other bentonites (Kunigel V1, Kunigel, and bentonite S-2) that have been also proposed for use as barrier materials. Very good agreement was found in all the cases between the experimental swelling pressures and the swelling pressures obtained using the proposed equations. The use of the proposed equations is based on the weighted average valency of the cations present in bentonites, since the valency of the cations present has a significant influence on the swelling pressure.Key words: clays, compressibility, swelling pressure, expansive soils, chemical properties, radioactive waste disposal.
Influence of reaction piles on the behaviour of a test pile in static load testing
Authors: Kitiyodom Pastsakorn , Matsumoto Tatsunori , Kanefusa Nao
Published: July 2004

This paper employs a simplified analytical method to investigate the influence of reaction piles on the loaddisplacement behaviour of a test pile in static load testing. A parametric study is conducted to examine the effects of factors such as pile spacing ratio, pile slenderness ratio, and pile soil stiffness ratio. Several soil profiles are considered in the study. The parametric study also includes the cases of static load testing in the lateral direction. The correction factors for the initial pile head stiffness obtained from static pile load tests with the use of reaction piles are given in charts. Furthermore, analyses of centrifuge modelling of axially loaded piles are carried out using the simplified analytical method. Good agreements between the test results and the analysis results are demonstrated, and the applicability of the correction factors is verified.Key words: reaction piles, interaction, initial pile head stiffness, static vertical load testing, static lateral load testing, simplified analytical method.
An interpretation of structural degradation for three natural clays
Authors: Callisto Luigi , Rampello Sebastiano
Published: July 2004

The mechanical behaviour of natural clays is influenced by the degradation of the microstructure induced by the applied loads. The consequence of progressive damage to the natural microstructure is that it is not possible to describe the state of the soil in terms of effective stress components and void ratio only, and therefore it is not possible to locate a unique state boundary surface by normalizing stresses with respect to the equivalent pressure. In this paper it is shown that, by defining a normalizing pressure that accounts for the progressive loss of structure occurring during a test, the state of the soil during loading can be completely described in a normalized stress space. The laws linking the normalizing pressure to the degree of microstructure disruption are derived from the isotropic hardening laws of two constitutive models recently proposed for natural soils. The normalizing procedure is applied to the experimental results obtained on three natural clays of different depositional origin and with different mechanical properties. For the three clays, the parameters describing structure degradation permit the assessment of the rate of loss of structure with plastic strains. For the clays examined, the volumetric plastic strains are seen to play a major role, compared to the deviatoric plastic strains, in causing progressive disruption of the microstructure. Lastly, it is shown that the initial degree of structure and the rate of structure degradation can be related to the depositional conditions and the stress history of the clay deposits.Key words: clays, compressibility, fabricstructure of soils, laboratory tests, plasticity, shear strength.
Carbon monoxide poisoning associated with blasting operations close to underground enclosed spaces. Part 1. CO production and migration mechanisms
Authors: Martel Richard , Trépanier Luc , Lévesque Benoît , Sanfaçon Guy , Brousseau Patrick , Lavigne Marc-André , Boutin Louis-Charles , Auger Pierre , Gauvin Denis , Galarneau Louise
Published: July 2004

Explosives used for blasting operations in civil engineering works can generate large volumes of carbon monoxide (CO). The production of 1024 L of CO per kilogram of explosives blasted is theoretically possible. CO can migrate a considerable distance in the fractured rock of the blasted areas and then infiltrate closed spaces (sewage systems, manholes, basements of houses). In the Province of Quebec, in the last 10 years, seven people were poisoned by CO in their houses to the extent that they had to be treated in a hyperbaric chamber. Underground conduits broken by blasting, filling around underground conduits in road or house trenches, or fractured rock created by blasts between houses or between a house and a road are the different CO pathways identified in the Quebec incidents. Field tests done by our group show that (i) the structural geology of the rock formation (schistosity, family of joints and fractures) controls the direction and extent of gas migration in fractures generated by blasts; (ii) the confinement of the rock can affect the quantity of gas migrating in the fractured rock; (iii) significant concentrations of CO may persist in the fractured rock 7 days after a blast; (iv) advection is the initial mechanism of CO migration immediately after a blast, and the distance of migration varied from 8 m in the fractured rock to 20 m in the fills of a road trench; and (v) further CO migration by diffusion up to 15 m in the induced fractures and 30 m in fills may occur in the 3 days following a blast.Key words: carbon monoxide, blasting, poisoning, enclosed spaces, gas migration, house.
A new design method for retaining walls in clay
Authors: Osman Ashraf S , Bolton Malcolm D
Published: July 2004

Geotechnical design engineers used to rely on arbitrary rules and definitions of "factor of safety" on peak soil strength in limit analysis calculations. They used elastic stiffness for deformation calculations, but the selection of equivalent linear elastic models was always arbitrary. Therefore, there is a need for a simple unified design method that addresses the real nature of serviceability and collapse limits in soils, which always show a nonlinear and sometimes brittle response. An approach to this method can be based on a new application of the theory of plasticity accompanied by the introduction of the concept of "mobilizable soil strength." This approach can satisfy both safety and serviceability and lead to simple design calculations within which all geotechnical design objectives can be achieved in a single step of calculation. The proposed method treats a stress path in an element, representative of some soil zone, as a curve of plastic soil strength mobilized as strains develop. Designers enter these strains into a plastic deformation mechanism to predict boundary displacements. The particular case of a cantilevered retaining wall supporting an excavation in clay is selected for a spectrum of soil conditions and wall flexibilities. The possible use of the mobilizable strength design (MSD) method in decision-making and design is explored and illustrated.Key words: retaining wall, plasticity theory, design, finite element.
Effect of compaction pressure on consolidation behaviour of unsaturated silty soil
Authors: Estabragh A R , Javadi A A , Boot J C
Published: July 2004

The effect of compaction pressure on subsequent soil behaviour during isotropic consolidation has been investigated by conducting controlled-suction triaxial tests on samples of an unsaturated compacted silty soil. A comprehensive set of laboratory experiments was carried out in a double-walled triaxial apparatus on samples of unsaturated soil that were prepared using two different compaction pressures. The axis translation technique was used for creating the desired suctions in the samples. In the experiments, the soil samples were subjected to isotropic consolidation under constant suctions. The results show that different compaction pressures produce different fabrics in a soil and therefore affect the behaviour of the soil. The results also show that the value of yield stress and the location of the loadingcollapse (LC) yield curve are functions of soil fabric. Furthermore, it is shown that the slopes of normal consolidation lines for densely and loosely compacted samples differ in unsaturated conditions but are the same in saturated soils. A comparison is made between the behaviour of the dense and loose samples, and the difference in the behaviour is explained.Key words: suction, unsaturated soil, compaction, consolidation, soil fabric.
Three-dimensional numerical investigations of new Austrian tunnelling method (NATM) twin tunnel interactions
Authors: Ng C WW , Lee K M , Tang D KW
Published: July 2004

A series of systematic, three-dimensional coupled finite element analyses was carried out to investigate the multiple interactions between large parallel hypothetical twin tunnels constructed in stiff clay using the new Austrian tunnelling method. Special attention was paid to the influence of lagging distance between the twin tunnel excavated faces (LT) and the load-transfer mechanism between the two tunnels. It is found that LT has a stronger influence on the horizontal movement than on the vertical movement of each tunnel, and it significantly affects the shortening of the horizontal diameter of the tunnels. The change of pillar width appears to be an approximately linear function of LT. The location of the maximum settlement is offset from the centerline of the pillar, and the offset increases with a range of LT values. The magnitude of the maximum settlement is independent of LT, however. As LT increases, there is a transfer of load from the lagging (right) tunnel to the leading (left) tunnel, resulting in an increase in the bending moment in the left tunnel but a decrease in the bending moment in the right tunnel. There is a corresponding increase in the axial force at the left springline of the left tunnel and a decrease in the axial force at the right springline of the right tunnel. Due to the twin tunnel interactions, the distributions of pore-water pressures are highly nonsymmetrical at both tunnels.Key words: NATM, tunnel, interaction, three-dimensional, numerical.
Effect of groundwater regime on the behaviour of clayey slopes
Authors: Picarelli Luciano , Urciuoli Gianfranco , Russo Claudia
Published: July 2004

It is well known that many landslides, which occur every year in the world, are triggered by rainfall. The mechanics of slope movements due to pore pressure changes are not completely understood, however, and thus are the focus of this paper. Both the case of first-time slides and that of landslide reactivation are examined. It is shown that simple models can reproduce the processes of slope failure and may help in predicting slope behaviour.Key words: slope, failure, landslide, analysis, water table, clay.
The 2002 Canadian Geotechnical Colloquium: The role of soilpile interaction in foundation engineering
Authors: Naggar M Hesham El
Published: July 2004

Soilpile interaction (SPI) plays an important role in the analysis and design of foundations and structures. Geotechnical engineers have recognized this role, and many studies have focused on several aspects of the topic in the past four decades. As the third millennium begins, geotechnical engineers are challenged to provide more reliable and efficient foundation solutions to support larger, heavier, and more complicated structures. SPI must be thoroughly understood to properly address the issues that arise when designing foundations to meet these challenges. This presentation investigates some of the important features of SPI as they relate to some innovative applications in foundation engineering. Specific problems examined here include design of tapered piles where understanding SPI and interface conditions is utilized to develop efficient design procedures; construction of fibre-reinforced polymer (FRP) and thin-walled pipe piles using an innovative device that exploits the understanding of aspects of SPI during driving for efficient installation; and Statnamic pile load testing where analysis of SPI is used to establish the characteristics of the pile static behaviour from the dynamic loading event.Key words: tapered, piles, driving, fibre-reinforced polymer, Statnamic, load testing.
Modelling of curling in desiccating clay
Authors: Kodikara J K , Nahlawi H , Bouazza A
Published: July 2004

This paper investigates the significant curling that occurs when thin soil layers undergo desiccation. Curling deformations, in the form of (1) lifting off from the edges (generating a concave surface), or (2) lifting off from the middle (creating a convex surface), are reported in the drying of soft soil and concrete pavements in the field. This paper presents experimental observations of significant curling of both forms 1 and 2 in wet soil specimens under controlled drying conditions. A theoretical explanation for curling is presented on the basis of unsaturated soil mechanics. The curling was primarily attributed to differential shrinkage strain increments that occur down the soil profile and their variation with the progression of desiccation. Making use of nonlinear elasticity theory under large deformations and measured properties, the shrinkage and curling deformations were modelled using the FLAC (Fast Lagrangian Analysis of Continua) computer program. The modelling approach appears to capture the observed behaviour of curling during desiccation.Key words: shrinkage, clay, curling, suction, desiccation, moisture migration.
EFFICIENT TRAINING OF RBF NETWORKS FOR CLASSIFICATION
Authors: NABNEY IAN T.
Published: July 2004

Radial Basis Function networks with linear outputs are often used in regression problems because they can be substantially faster to train than Multi-layer Perceptrons. For classification problems, the use of linear outputs is less appropriate as the outputs are not guaranteed to represent probabilities. We show how RBFs with logistic and softmax outputs can be trained efficiently using the Fisher scoring algorithm. This approach can be used with any model which consists of a generalised linear output function applied to a model which is linear in its parameters. We compare this approach with standard non-linear optimisation algorithms on a number of datasets.
ON THE LIMIT CYCLE STRUCTURE OF THRESHOLD BOOLEAN NETWORKS OVER COMPLETE GRAPHS
Authors: VOUTSADAKIS GEORGE
Published: July 2004

In previous work, the limit structure of positive and negative finite threshold boolean networks without inputs (TBNs) over the complete digraph Knwas analyzed and an algorithm was presented for computing this structure in polynomial time. Those results are generalized in this paper to cover the case of arbitrary TBNs over Kn. Although the limit structure is now more complicated, containing, not only fixed-points and cycles of length 2, but possibly also cycles of arbitrary length, a simple algorithm is still available for its determination in polynomial time. Finally, the algorithm is generalized to cover the case of symmetric finite boolean networks over Kn.
COMPLEXITY OF ERROR HYPERSURFACES IN MULTILAYER PERCEPTRONS
Authors: LIANG XUN
Published: July 2004

Error hypersurfaces are very valuable to study because of their unique status in multilayer perceptron research. Given the architecture of a multilayer perceptron, if the pattern sets are different, so are the respective error hypersurfaces in the multilayer perceptron. Using the theory of groups and Polya Theorem, this paper constructs classes of congruent pattern sets and classes of congruent error hypersurfaces, and proves that the number of classes of congruent pattern sets is equal to the number of congruent error hypersurfaces. Calculation results lead to much fewer classes of congruent error hypersurfaces than the total error hypersurfaces, and show that as the input dimension N increases, the former number increases at a much lower rate than the latter number, thus simplifying the understanding of the complexity of classes of error hypersurfaces.
A NEURAL-NETWORK APPROACH FOR VISUAL CRYPTOGRAPHY AND AUTHORIZATION
Authors: YUE TAI-WEN , CHIANG SUCHEN
Published: July 2004

In this paper, we propose a neural-network approach for visual authorization, which is an application of visual cryptography (VC). The scheme contains a key-share and a set of user-shares. The administrator owns the key-share, and each user owns a user-share issued by the administrator from the user-share set. The shares in the user-share set are visually indistinguishable, i.e. they have the same pictorial meaning. However, the stacking of the key-share with different user-shares will reveal significantly different images. Therefore, the administrator (in fact, only the administrator) can visually recognize the authority assigned to a particular user by viewing the information appearing in the superposed image of key-share and user-share.

This approach is completely different from traditional VC approaches. The salient features include: (i) the access schemes are described using a set of graytone images, and (ii) the codebooks to fulfil them are not required; and (iii) the size of share images is the same as the size of target image.
SIMULATION OF CONSENSUS MODEL OF DEFFUANT et al. ON A BARABÁSI–ALBERT NETWORK
Authors: STAUFFER D. , MEYER-ORTMANNS H.
Published: July 2004

In the consensus model with bounded confidence, studied by Deffuant et al. (2000), two randomly selected people who differ not too much in their opinion both shift their opinions towards each other. Now we restrict this exchange of information to people connected by a scale-free network. As a result, the number of different final opinions (when no complete consensus is formed) is proportional to the number of people.
AN ALGORITHM TO GENERATE TOROIDAL AND HELICAL CAGE STRUCTURES USING PENTAGONS, HEXAGONS AND HEPTAGONS
Authors: YAZGAN EFE , TAŞCI EMRE , ERKOÇ ŞAKIR
Published: July 2004

An algorithm to generate toroidal or helical cage structures has been developed. Any toroidal or helical structure can be generated following four stages. In the first stage a Fonseca type unit cell and its symmetrical counterpart is formed which represents one-fifth of a toroid. In the second stage one-fifth fragment of the torus is fully obtained by applying geometry optimization to the structure obtained in the first stage. In the third stage the torus fragment obtained in the second stage is reproduced five times and connected to each other to generate either toroidal or helical structure. In the last stage a final optimization process is reapplied to get the complete structure desired.
SIMULATIONS OF PEPTIDE MODELS IN A SOLVENT
Authors: ARKIN HANDAN
Published: July 2004

The three-dimensional structures of the heptapeptide deltorphin ( H - Tyr 1- D - Met 2- Phe 3- His 4- Leu 5- Met 6- Asp 7- NH 2) are studied in aqueous solution using Energy Landscape Paving (ELP) method. The effect of a solvation energy term on the conformations are determined by analyzing Ramachandran plots. The structures are compared with experimental NMR data. By minimizing the energy structures, the low-energy microstates of the molecule in aqueous solution are determined.
EVOLUTION OF POPULATION WITH SEXUAL AND ASEXUAL REPRODUCTION IN CHANGING ENVIRONMENT
Authors: HE MINGFENG , YU CHANGLIANG , RUAN HONGBO , YAO LEI
Published: July 2004

Using a lattice model based on Monte Carlo simulations, we study the role of the reproduction pattern on the fate of an evolving population. Each individual is under the selection pressure from the environment and random mutations. The habitat ("climate") is changing periodically. Evolutions of populations following two reproduction patterns are compared, asexual and sexual. We show, via Monte Carlo simulations, that sexual reproduction by keeping more diversified populations gives them better chances to adapt themselves to the changing environment. However, in order to obtain a greater chance to mate, the birth rate should be high. In the case of low birth rate and high mutation probability there is a preference for the asexual reproduction.
COMPARATIVE STUDY OF THERMAL FLOWS WITH DIFFERENT FINITE VOLUME AND LATTICE BOLTZMANN SCHEMES
Authors: AL-ZOUBI AHMAD , BRENNER GUNTHER
Published: July 2004

In the present paper, a comparative study of numerical solutions for steady flows with heat transfer based on the finite volume method (FVM) and the relatively new lattice Boltzmann method (LBM) is presented. In the last years, the LB methods have challenged the classical FV methods to solve the Navier–Stokes equations and have proven to be superior in accuracy and efficiency for certain applications. Most of these studies were related to the transport of mass and momentum. In the meantime, significant effort has been invested in the application of the LBM to simulate flows including heat transfer. The studies in the present paper are the analysis of performance and accuracy aspects of LBM applied to the prediction of these flows. For a fully developed laminar flow between parallel plates, analytical solutions for the heat transfer in fully developed thermal boundary layers are available and may be compared with the respective numerical results. Finally, a hybrid approach is proposed to circumvent numerical problems of the thermal LB methods.
NONLINEAR INDICES ANALYZING METHOD FOR MOLECULAR DYNAMICS OF PROTEIN DYNAMICAL TRANSITION
Authors: ZHANG L. L. , RUAN Q. , ZHOU L. X.
Published: July 2004

We introduce four kinds of nonlinear indices into the analysis of free energy data produced by protein simulation with molecular dynamics. They are fractional dimension, approximate entropy, Poincare plot indices and predictability index with neural network. In this paper, the 200 K dynamical transition of myoglobin is used as an example, and the free energy data of the simulation is taken as time series to calculate the nonlinear indices. We show that all these indices as a function of temperature allow to indicate the dynamical transition with an obvious turning point, a "valley" or a "peak" around 200 K.
EXTENDED TANH-METHODS AND SOLITONIC SOLUTIONS OF THE GENERAL SHALLOW WATER WAVE MODELS
Authors: HONG WOO-PYO , PARK SEOUNG-HWAN
Published: July 2004

Based on the two recent extended tanh-function methods, we find traveling-wave solutions for the general shallow water wave models. The obtained solutions include periodical, singular and solitary-wave solutions.
WHAT'S IN A NAME?
Authors: DA FONTOURA COSTA LUCIANO
Published: July 2004

Among the several findings deriving from the application of complex network formalism to the investigation of natural phenomena, the fact that linguistic constructions follow power laws presents special interest for its potential implications for psychology and brain science. By corresponding to one of the most essentially human manifestations, such language-related properties suggest that similar dynamics may also be inherent to the brain areas related to language and associative memory, and perhaps even consciousness. The present work reports a preliminary experimental investigation aimed at characterizing and modeling the flow of sequentially induced associations between words from the English language in terms of complex networks. The data is produced through a psychophysical experiment where a word is presented to the subject, who is requested to associate another word. Complex network and graph theory formalism and measurements are applied in order to characterize the experimental data. Several interesting results are identified, including the characterization of attraction basins, association asymmetries, context biasing, as well as a possible power-law underlying word associations, which could be explained by the appearance of strange loops along the hierarchical structure underlying word categories.
A REALISTIC TWO-LANE CELLULAR AUTOMATON MODEL FOR TRAFFIC FLOW
Authors: JIA BIN , JIANG RUI , WU QING-SONG
Published: July 2004

This paper extends a recently proposed single-lane cellular automaton model [Li et al., Phys. Rev. E64, 066128 (2001)], which considers the velocity effect of the preceding car, to two-lane traffic system. The traffic behaviors in both homogeneous system and inhomogeneous system are investigated. For homogeneous traffic, it is shown that the velocity effect enhances the maximum flux but does not change the qualitative properties of the fundamental diagram. Nevertheless, the qualitative changes of the lane changing frequency and congested pattern occur. In the inhomogeneous system, the honk effect is studied. It is found that the honk effect first strengthens then weakens with the increase of R, the ratio of slow cars to all cars.
A COMPARATIVE STUDY OF EMPIRICAL POTENTIAL ENERGY FUNCTIONS: APPLICATIONS TO SILICON MICROCLUSTERS
Authors: ERKOÇ ŞAKIR , TAKAHASHI KUNIO
Published: July 2004

A comparative study has been performed for silicon microclusters, Si 3 and Si 4, considering fifteen different empirical potential energy functions. It has been found that only two of the empirical potential energy functions give linear structure more stable for Si 3, the remaining potential functions give triangular structure as more stable. In the case of Si 4 microclusters eight potential functions give open tetrahedral structure as more stable, two functions give perfect tetrahedral as more stable, three functions give square structure as more stable, and two functions give linear structure as more stable.
GLOBALLY SYNCHRONIZED OSCILLATIONS IN AN ONE-DIMENSIONAL CELLULAR AUTOMATON
Authors: JIMÉNEZ-MORALES FRANCISCO , TOMASSINI MARCO
Published: July 2004

Using a genetic algorithm a population of one-dimensional binary cellular automata is evolved to perform a computational task for which the best evolved rules cause the concentration to display a period-three oscillation. One run is studied in which the final state reached by the best evolved rule consists of a regular pattern or domain Λ, plus some propagating particles. It is shown that globally synchronized period-three oscillations can be obtained if the lattice size L is a multiple of the spatial periodicity S(Λ) of the domain. When L=m.S(Λ)-1 there is a cyclic particle reaction that keeps the system in two different phases and the concentration has a temporal periodicity that depends on the lattice size. The effects of random noise on the evolved cellular automata has also been investigated.
COMPLEXITY AND HIERARCHICAL MAJORITY RULE
Authors: GÖTZ IVAN , RUBINSTEIN ISAAK , TZVETKOV EUGENE , ZALTZMAN BORIS
Published: July 2004

Hierarchical structure is an essential part of complexity, an important notion relevant for a wide range of applications ranging from biological population dynamics through robotics to social sciences. In this paper we propose a simple cellular-automata tool for study of hierarchical population dynamics.
EQUILIBRIUM TIMES FOR THE MULTICANONICAL METHOD
Authors: GUERRA M. L. , MUÑOZ J. D.
Published: July 2004

This work measures the time to equilibrium for the multicanonical method on the 2D-Ising system by using a new criterion, proposed here, to find the time to equilibrium, t eq , of any sampling procedure based on a Markov process. Our new procedure gives the same results that the usual one, based on the magnetization, for the canonical Metropolis sampling on a 2D-Ising model at several temperatures. For the multicanonical method we found a power-law relationship with the system size, L, of t eq =0.27(15) L2.80(13) and with the number of energy levels to explore, k E , of [Formula: see text], in perfect agreement with the above result. In addition, a kind of critical slowing down was observed around the critical energy. Our new procedure is completely general, and can be applied to any sampling method based on Markov processes.
THE EFFECTS OF METALLIC CONTACTS ON SILICON NANOSTRUCTURES STUDIED QUANTUM MECHANICALLY
Authors: MAZZONE A. M. , MORANDI V.
Published: July 2004

The purpose of this study is to get insight into the effects of metallic contacts on nanocrystalline silicon material. Therefore the Hartree–Fock formulation at semiempirical level has been applied to silicon grains coated with an aluminum film. The calculations describe the electronic configuration of the grains and the effects induced by the presence of the metallic atoms. The parameters investigated are the binding and adsorption energies, the ionization potential and the Mulliken charges. Though no inter-diffusion or lateral diffusion of metal atoms on silicon is observed, the electronic properties of grains appear perceptibly altered by the metallic overlayer and the strength of bonding is generally lowered in the structures with the contacts. Furthermore the built-in potential across the entire device exhibits a functional dependence on both the grain and the contact geometry which could be usefully applied for the fabrication of unconventional Schottky barriers devices.
LATTICE BOLTZMANN SIMULATION OF VAPOR–LIQUID EQUILIBRIUM ON 3D FINITE LATTICE
Authors: MAYER GUSZTÁV , HÁZI GÁBOR , IMRE ATTILA R. , KRASKA THOMAS , YELASH LEONID V.
Published: July 2004

Numerical calculations for three-dimensional vapor–liquid equilibria have been accomplished by lattice Boltzmann simulations. The aim of this investigation is to test the capability of the lattice Boltzmann method in comparison with solutions obtained by the underlying equation of state. As a result we have found a finite-size effect (just like the ones obtained in one and two dimensions) at small lattice sizes for all phase equilibrium properties and related constants such as the critical exponent β. Here, systems with up to 1003 lattice sites are investigated. Reasonable convergence has been obtained from about 323 lattice sites.
EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF IRON IONS IN THE 3B2O3·KF GLASS MATRIX
Authors: ARDELEAN I. , PASCUTA P.
Published: July 2004

Glasses of the x Fe 2 O 3·(100–x)[3 B 2 O 3· KF ] system, with 0<x≤35 mol %, were investigated by means of EPR and magnetic susceptibility measurements. When increasing the iron content the EPR absorption spectra undergo modification reflecting structural changes of the glass matrix and also the distribution and valence states of iron ions. The magnetic measurement data pointed out the character of interaction involving iron ions as depending on concentration and the simultaneous presence of both Fe 3+ and Fe 2+ ionic species.
EPR AND MAGNETIC SUSCEPTIBILITY STUDIES OF MANGANESE IONS IN Bi2O3·CdO GLASS MATRIX
Authors: ARDELEAN I. , TODOR IOANA , CICEO-LUCACEL RALUCA , MANIU DANA
Published: July 2004

Glasses of the x MnO ·(100–x)[ Bi 2 O 3· CdO ] system with 0<x≤50 mol %, were prepared and studied by means of EPR and magnetic susceptibility measurements. The EPR investigations indicated the compositional domains favorable to isolated manganese ions or to those magnetically clustered. The magnetic measurements evidenced the presence of both Mn 2+ and Mn 3+ ions, with their relative content depending on the MnO concentration. The prevalence of the dipolar and respectively the superexchange interactions between the manganese ions can be correlated with the relative content of the Mn 2+ and Mn 3+ species.
PATH INTEGRAL APPROACH TO A SINGLE POLYMER CHAIN WITH RANDOM MEDIA
Authors: KUNSOMBAT CH. , SA-YAKANIT V.
Published: July 2004

In this paper we consider the problem of a polymer chain in random media with finite correlation. We show that the mean square end-to-end distance of a polymer chain can be obtained using the Feynman path integral developed by Feynman for treating the polaron problem and successfuly applied to the theory of heavily doped semiconductor. We show that for short-range correlation or the white Gaussian model we derive the results obtained by Edwards and Muthukumar using the replica method and for long-range correlation we obtain the result of Yohannes Shiferaw and Yadin Y. Goldschimidt.

The main idea of this paper is to generalize the model proposed by Edwards and Muthukumar for short-range correlation to finite correlation. Instead of using a replica method, we employ the Feynman path integral by modeling the polymer Hamiltonian as a model of non-local quadratic trial Hamiltonian. This non-local trial Hamiltonian is essential as it will reflect the translation invariant of the original Hamiltonian. The calculation is proceeded by considering the differences between the polymer propagator and the trial propagator as the first cumulant approximation. The variational principle is used to find the optimal values of the variational parameters and the mean square end-to-end distance is obtained. Several asymptotic limits are considered and a comparison between this approaches and replica approach will be discussed.
THEORY OF THE DC MAGNETOTRANSPORT IN LATERALLY MODULATED QUANTUM HALL SYSTEMS NEAR FILLING ν=½
Authors: ZIMBOVSKAYA NATALYA , GUMBS GODFREY , BIRMAN JOSEPH L.
Published: July 2004

A quasiclassical theory for DC magnetotransport in a modulated quantum Hall system near filling factor ν=½ is presented. A weak one-dimensional electrostatic potential acts on the two-dimensional electron gas. Closed form analytic expressions are obtained for the resistivity ρ⊥ corresponding to a current at right angles to the direction of the modulation lines as well as a smaller component ρ‖ for a current along the direction of the modulation lines. It is shown that both resistivity components are affected by the presence of the modulation. Numerical results are presented for ρ⊥ and ρ‖ and show reasonable agreement with the results of recent experiments.
EQUILIBRIUM AND NONEQUILIBRIUM BEHAVIOR OF THE BLUME–EMERY–GRIFFITHS MODEL USING THE PAIR APPROXIMATION AND PATH PROBABILITY METHOD WITH THE PAIR DISTRIBUTION
Authors: ERDINÇ AHMET , KESKIN MUSTAFA
Published: July 2004

Equilibrium properties of Blume–Emery–Griffiths (BEG) model with the arbitrary bilinear (J), biquadratic (K) and crystal field interaction (D) are studied on a body centered cubic lattice by using the pair approximation of the cluster variation method, which is identical to the Bethe approximation. The thermal variation of the stable, metastable and unstable dipole and quadrupolar moment order parameters are found for various values of the two different coupling parameters J/K and D/K. The phase transitions of the stable, metastable and unstable branches of the order parameters are investigated extensively. The critical temperatures in the case of a second-order phase transition are obtained for different values of J/K and D/K by the Hessian determinant. The first-order phase transition temperature is determined by matching the values of the two branches of the free energy values. On the other hand, nonequilibrium behavior of the model is studied by using the path probability method with the pair distribution and the set of nonlinear differential equations, which is also called the dynamic or rate equations, is obtained. The solution of the dynamic equations is expressed by means of flow diagrams. The stable, metastable and unstable solutions are shown and the "overshooting" phenomenon is seen in the flow diagrams, explicitly. The role of the unstable points, as separators between the stable and the metastable points, is described and how a system freezes in a metastable state is also investigated, extensively. Moreover, the dynamic equations are also solved by using the Runge–Kutta method in order to study the relaxation of order parameters. In this investigation, the "flatness" property of metastable states and the "overshooting" phenomenon are seen explicitly.
STRUCTURE TYPES OF INORGANIC COMPOUNDS AND ADSORBED LAYERS
Authors: HAUCK J. , MIKA K.
Published: July 2004

2D and 3D lattice complexes with increased self-coordination numbers Ti (i=1–3), of nearest, second and third neighbors were derived for characteristic Wyckoff sets with zero or one parameters. Structure types of adsorbed atoms in 2D or elements A in 3D and A x B y compounds are approximated to the list of lattice complexes. Covalent bonding or electronic effects of atoms such as lone electron pairs or Jahn–Teller distortion give rise to deviations from lattice complexes.
STUDY OF A PAIR OF COUPLED CONTINUUM EQUATIONS MODELING SURFACE GROWTH: INTERPLAY BETWEEN SURFACE DIFFUSION, DESORPTION-ACCRETION AND SCHWOEBEL BACK DIFFUSION
Authors: HUDA AIN-UL , DUTTA OMJYOTI , MOOKERJEE ABHIJIT
Published: July 2004

In this communication we shall focus on the three microscopic processes whose interplay determine the surface morphology of MBE growth: namely, surface diffusion, desorption and accretion and Schwoebel back diffusion. We gain insight into the dynamics of growth via one-loop perturbative techniques. This allows us to analyze our numerical data. We conclude that there is a crossover behavior from a roughening regime to a very long-time, large length scale smoothening regime.
CONFIGURATIONAL ENTROPY FOR STONE-INFLATION HEXAGONAL AND OCTAGONAL PATTERNS
Authors: ESCUDERO JUAN GARCíA
Published: July 2004

In a recent paper several species of octagonal patterns have been introduced with the help of a construction which allows us to derive them by means of inflation rules. Non-deterministic patterns can be generated by composition of the inflation rules. In this paper we show how a similar construction produces patterns with hexagonal symmetry. The non-deterministic rhombus–triangle tilings are obtained by local rearrangements of tiles which are included in the inflation rules. This property allows to compute the configurational entropy.
PRE-PROCESSING DESIGN FOR MULTIWAVELET FILTERS USING NEURAL NETWORKS
Authors: MORIMOTO AKIRA , ASHINO RYUICHI , VAILLANCOURT RÉMI
Published: July 2004

A pre-processing design using neural networks is proposed for multiwavelet filters. Various numerical experiments are presented and a comparison is given between neural network pre-processing and a pre-processing for solving linear systems. Neural network pre-processing produces a good approximation for a large number of terms and converges rapidly.
THE TIMING OF FACIAL MOTION IN POSED AND SPONTANEOUS SMILES
Authors: COHN J. F. , SCHMIDT K. L.
Published: July 2004

Almost all work in automatic facial expression analysis has focused on recognition of prototypic expressions rather than dynamic changes in appearance over time. To investigate the relative contribution of dynamic features to expression recognition, we used automatic feature tracking to measure the relation between amplitude and duration of smile onsets in spontaneous and deliberate smiles of 81 young adults of Euro- and African-American background. Spontaneous smiles were of smaller amplitude and had a larger and more consistent relation between amplitude and duration than deliberate smiles. A linear discriminant classifier using timing and amplitude measures of smile onsets achieved a 93% recognition rate. Using timing measures alone, recognition rate declined only marginally to 89%. These findings suggest that by extracting and representing dynamic as well as morphological features, automatic facial expression analysis can begin to discriminate among the message values of morphologically similar expressions.
A ROBUST DIGITAL WATERMARKING SYSTEM BY SPECIFYING THE EMBEDDED POSITION USING WAVELET TRANSFORM
Authors: UENO YOSHITO , MURAKAMI KENJI
Published: July 2004

In this paper, we propose how to embed the watermarking to an image under the wavelet transform precisely utilizing an appropriate filter for specifying the embedded position and clustering the variance of multi-resolution representation of an image. This system has a feature of the robustness against alteration attacks of malicious users utilizing the precise detection of embedded watermarks.
A FAST WAVELET-BASED VIDEO CODEC AND ITS APPLICATION IN AN IP VERSION 6-READY SERVERLESS VIDEOCONFERENCING SYSTEM
Authors: CYCON H. L. , PALKOW M. , SCHMIDT T. C. , WÄHLISCH M. , MARPE D.
Published: July 2004

The purpose of this paper is twofold: On the one hand, we propose a fast wavelet-based video codec which is implemented into a real-time video conferencing tool. The proposed codec uses temporal frame difference coding, a computationally low-complex 5/3 tap wavelet transform, and a fast entropy coding scheme based on Golomb–Rice codes. On the other hand, we present an application of the video conferencing tool in a serverless peer-to-peer IP-based communication framework. For mobile communication we propose a simple, ready-to-use location scheme for video conference users in a global network.
STRUCTURAL AND GEOMETRIC CHARACTERISTICS OF SETS OF CONVERGENCE AND DIVERGENCE OF MULTIPLE FOURIER SERIES OF FUNCTIONS WHICH EQUAL ZERO ON SOME SET
Authors: BLOSHANSKII I. L.
Published: July 2004

Let E be an arbitrary set of positive measure in the N-dimensional cube TN=(-π,π)N⊂ℝN, N≥1, and let f(x)=0 on E. Let [Formula: see text] be some linear subspace of L1(TN). We investigate the behavior of rectangular partial sums of multiple trigonometric Fourier series of a function f on the sets E and TN\E depending on smoothness of the function f (i.e. of the space [Formula: see text]), and, as well, of structural and geometric characteristics of the set E (SGC(E)). Thus, we are describing pairs [Formula: see text]. It is convenient to formulate and investigate the posed question in terms of generalized localization almost everywhere (GL) and weak generalized localization almost everywhere (WGL). This means that for the multiple Fourier series of a function f, that equals zero on the set E, convergence almost everywhere is investigated on the set E (GL), or on some of its subsets E1⊂E, of positive measure (WGL).
REASONING ABOUT FUNCTIONALITY OF CORE MATCHING FUNCTIONS FOR INFORMATION RETRIEVAL
Authors: LI JIAN PING , SONG DAWEI , YANG YONG QIN , TANG YUAN YAN
Published: July 2004

Traditional benchmarking methods for information retrieval (IR) are based on experimental performance evaluation.1–14 Although the metrics precision and recall can measure the effectiveness of a system, it cannot assess the underlying model. Recently, a theory of "aboutness" has been used for functional benchmarking of IR. Latest research shows that the functionality of an IR model is largely determined by its retrieval mechanism, i.e. the matching function. In particular, containment and overlapping (either with or without a threshold value) are the core IR matching functions. The objective of this paper is to model the containment and overlapping matching functions using an aboutness-based framework and analyze them from an abstract and theoretical viewpoint. Separate aboutness relations for containment, pure-overlapping (i.e. without threshold) and threshold-overlapping matching functions are defined, and the sets of properties supported by them are derived and analyzed respectively. These three relations can be used to determine and explain the functionality of an IR system and how the functionality affects the performance of the system. Moreover, they can provide the design guidelines for new IR systems.
LEDGF regulation of alcohol and aldehyde dehydrogenases in lens epithelial cells: stimulation of retinoic acid production and protection from ethanol toxicity
Authors: Fatma Nigar , Kubo Eri , Chylack Leo T. , Shinohara Toshimichi , Akagi Yoshio , Singh Dhirendra P.
Published: July 2004

Retinoic acid (RA) is required for the normal growth and maintenance of many cell types, including lens epithelial cells (LECs). Alcohol (ADH) and aldehyde (ALDH) dehydrogenases are implicated in cellular detoxification and conversion of vitamin A to RA. Lens epithelium-derived growth factor (LEDGF) provides cellular protection against stress by transactivating stress-associated genes. Here we show evidence that LEDGF binds and transactivates heat shock (nGAAn) and stress response (A/TGGGGA/T) elements in the promoters of ADH1, ADH4, and retinaldehyde 2 (RALDH2) genes. Electrophoretic mobility and supershift assays disclosed specific binding of LEDGF to nGAAn and A/TGGGGA/T elements in these gene promoters. Transfection experiments in LECs with promoters linked to a chloramphenicol acetyltransferase (CAT) reporter gene along with LEDGF cDNA revealed higher CAT activity. RT-PCR results confirmed that LECs overexpressing LEDGF contained increased levels of ADH1, ADH4, and RALDH2 mRNA. Notably, LECs displayed higher LEDGF mRNA and protein expression during ethanol stress. Cells overexpressing LEDGF typically exhibited elevated RA levels and survived well during ethanol stress. The present findings indicate that LEDGF is one of the transcriptional activators of these genes that facilitates cellular protection against ethanol stress and plays a role in RA production.