bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of the Contour Method of Residual Stress Measurement in a MIG 2024 Weld by Neutron and Synchrotron X-ray Diffraction
Authors: Zhang Y. , Ganguly S. , Stelmukh V. , Fitzpatrick M.E. , Edwards L.
Published: November 2004

The contour method is a newly-invented destructive technique of residual stress measurement and has been receiving increasing interest. It is advisable to validate such new methods by comparison with other well-established techniques. For this purpose, contour measurements were performed on a MIG 2024-T351 aluminium alloy welded plate. The result has been compared with the results from neutron and synchrotron X-ray and shows a favourable agreement.
The Role of Residual Stress Measurement in the Development of Laser Peening
Authors: Hill Michael R. , Dewald Adrian T. , Rankin Jon E. , Lee Matthew J.
Published: November 2004

This paper provides a summary of residual stress measurements performed in the development of a specific application of laser peening. Laser peening is an emerging surface treatment for metals that imparts compressive residual stress near the surface by introducing cold work. Since residual stress is a key outcome of the process, its measurement is an important process diagnostic. The first part of this work demonstrates the effects of specific laser peening process variations on the residual stress profile imparted to a corrosion-resistant nickel alloy (Alloy 22, UNS N06022). The second part of this work demonstrates measurements of a two-dimensional spatial distribution of the weld-direction residual stress component for a thick welded joint in the as-welded and laser peened conditions.
International Materials Institutes [IMI], Advanced Neutron Scattering Network for Education and Research [ANSWER]: With a Focus on Mechanical Behavior of Materials
Authors: Liaw P.K. , Choo H. , Buchanan R.A. , Hubbard C.R. , Wang X.L.
Published: November 2004

Neutron scattering is one of the most powerful characterization techniques available for materials research, and its proven capabilities and anticipated potentials justify the 1.4-billion dollar construction of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) as well as a number of multi-million dollar facility upgrades at the Los Alamos Neutron Science Center (LANSCE), Intense Pulsed Neutron Source (IPNS), and High Flux Isotope Reactor (HFIR) in the US, and at ISIS, the Rutherford Appleton Laboratory in UK. However, while the multi-billion dollar constructions are on-going all around the world, currently there is no concerted effort within the US in advancing the science and education in the application of neutron scattering in materials research, specifically in the study of mechanical behavior of advanced materials. To be better positioned in the scientific research at the international level, it is important to develop a network with international counterparts. Therefore, a group of the most active researchers in the neutron-scattering materials-research field will form an international network through the International Materials Institutes (IMI)-Advanced Neutron Scattering netWork for Education and Research (ANSWER) with a focus on mechanical behavior of materials. The IMI provides a synergistic effort in advancing the fundamental understanding of mechanical behavior of materials at the atomic level using state-of-the-art neutron sources in the world.
Mosaic Size Distributions in an Aluminum Bi-crystal Deformed by Channel Die Plane Strain Compression
Authors: Lima E.B.F. , Pyzalla A.R. , Reimers W. , Kuo J.-C. , Raabe D.
Published: November 2004

Rocking curves and ω-2θ mappings were determined by X-ray diffraction at different positions of an aluminum bi-crystal that was deformed by channel die plane strain compression. The width of the rocking curves obtained for the two crystals is different. Also within each crystal differences in the rocking curve width show that plastic deformation during channel die plane strain compression was inhomogeneous.
SALSA: Strain Analyser for Large and Small Scale Engineering Applications
Authors: Bruno G. , Pirling T. , Withers P.J. , Hutt W. , Rowe S.
Published: November 2004

Neutron diffraction has already matured into a very reliable bulk and near surface technique for residual stress (RS) analysis with worldwide standards being established. As a result the demand for time-efficient neutron strain mapping is increasing very rapidly. The strain mapper, strain analyser for large and small scale engineering applications (SALSA) at the ILL, the world’s most powerful steady neutron source, is a new instrument for RS analysis in engineering components, designed to meet this demand. Thanks to the high flux of the new m = 2 supermirror guide (gaining a factor 3–5 on the existing guide), SALSA will increase the range of engineering applications by improving the resolution, radically extending sample manipulation, shortening the measurement times and simplifying data processing. It is designed to allow multi-axial manipulation of components of more than 1 m length and more than 500 kg weight, yet having a spatial resolution of 0.5×0.5×0.5 mm3 at a depth up to several centimetres. At the same time, precise near surface measurement will be standard, owing to the presence of radial focusing collimators and to a positioning precision better than 50 μm.
Measurement and Prediction of Residual Stresses in Aluminium Friction Stir Welds
Authors: Steuwer A. , Peel M. , Withers P.J. , Dickerson T. , Shi Q. , Shercliff H.R.
Published: November 2004

Friction stir welding (FSW) is a solid-state process that offers the possibility of creating high quality joints between dissimilar aluminium alloys. However, to date little is known about the distribution of residual stresses within such joints. In this study, a combined modelling and experimental approach has been undertaken in an attempt to clarify this situation and develop a practical predictive tool. The model appears to have captured the asymmetry of the welding process but the peak residual strain is typically 30% higher than measured by synchrotron X-ray diffraction indicating that some optimisation is required.
A Non-destructive Strain and Phase Investigation of a Friction Stir Weld Joint between an Al-base Metal Matrix Composite and a Monolithic Al Alloy Using Synchrotron Radiation
Authors: Martins R.V. , Honkimäki V.
Published: November 2004

The through thickness strain and depth resolved phase distribution in a dissimilar friction stir weld (FSW) of monolithic AA2024T3 to AA2014 + 34 vol.% Al2O3 is measured non-destructively. The measurements are performed using a novel strain and phase mapping technique. The technique is based on the use of a focused high-energy synchrotron beam, a novel spiral slit system, and an area detector system. The strong asymmetry of the calculated residual stress profiles is mainly due to the dominance of hydrostatic stresses in the metal matrix composite (MMC) side of the weld. Tensile stresses up to + 190 MPa are observed in the Al phase. The large residual stress gradient in the weld centre correlates with the weak mixing of the dissimilar plate materials.
Education, infant mortality, and low birth weight in Sweden 1973—1990: Emergence of the low birth weight paradox
Authors: Gisselmann Marit D.
Published: November 2004

Aims: Educational differences in infant mortality, birth weight, and birth weight-specific infant mortality in Sweden were analysed. The ``low birth weight paradox'', where low birth weight infants have a lower mortality risk if born to women of lower rather than higher social strata, was addressed. Methods: The study includes about a million single births 1973—90 to women born 1946—60. There were 6,544 infant deaths and 35,334 low birth weight infants. Analysis conducted on six-year time periods was restricted to 652,859 births to women aged 25—32 at the time of delivery. Odds ratios and 95% CI were estimated by logistic regression. Birth weight-specific infant mortality rates were calculated by education. Results: Infants of women with low/low intermediate education had significantly higher odds ratios than those of highly educated women of being of low birth weight or of dying. If one compares only the infants of women with low and high education, these differences were accentuated over time. The low birth weight paradox appears over time. Conclusion: The widening differences in infant mortality and low birth weight over time may be caused by the decrease in women with low education, signifying increased selection and growing social disadvantage in this group. The emergence of the low birth weight paradox suggests that the distribution of causes of low birth weight differs between educational groups, and further that these causes are differently related to infant mortality. To disentangle these two groups of causes and their effects on infant mortality seems highly relevant.
Association between age, gender and reasons for smoking cessation
Authors: Grøtvedt Liv , Stavem Knut
Published: November 2004

Aims: To contribute to improved programs for smoking cessation, the authors wanted to assess the relationships between age, gender and ex-smokers' quitting reasons and examine predictors of the most commonly reported quitting reasons. Methods: A questionnaire was mailed to 11,919 subjects in Akershus County, Norway. Among the 7,697 respondents (65%), self-reported reasons for smoking cessation in 1,715 ex-smokers were analysed. Using cross-tables and multivariate logistic regression, associations between age, gender, and reported quitting reasons were examined. Results: Men were more likely to have stopped smoking to improve physical fitness, or out of consideration for other family members than the children, and less likely to have quit out of consideration for their own children, or in solidarity with a spouse that stopped smoking. In multivariate logistic regression analysis, age was a predictor of all seven most common reasons to quit smoking. Gender, education, and the physical component of health status each predicted three of the seven quitting reasons. Conclusions: In the study sample, differences in smoking cessation behavior and reported quitting reasons were found according to both age and gender. Smoking cessation programs should be tailored to the relevant target groups, including stratification according to age and gender.
Live cell imaging of the assembly, disassembly, and actin cable–dependent movement of endosomes and actin patches in the budding yeast, Saccharomyces cerevisiae
Authors: Huckaba Thomas M. , Gay Anna Card , Pantalena Luiz Fernando , Yang Hyeong-Cheol , Pon Liza A.
Published: November 2004

Using FM4-64 to label endosomes and Abp1p-GFP or Sac6p-GFP to label actin patches, we find that (1) endosomes colocalize with actin patches as they assemble at the bud cortex; (2) endosomes colocalize with actin patches as they undergo linear, retrograde movement from buds toward mother cells; and (3) actin patches interact with and disassemble at FM4-64–labeled internal compartments. We also show that retrograde flow of actin cables mediates retrograde actin patch movement. An Arp2/3 complex mutation decreases the frequency of cortical, nonlinear actin patch movements, but has no effect on the velocity of linear, retrograde actin patch movement. Rather, linear actin patch movement occurs at the same velocity and direction as the movement of actin cables. Moreover, actin patches require actin cables for retrograde movements and colocalize with actin cables as they undergo retrograde movement. Our studies support a mechanism whereby actin cables serve as “conveyor belts” for retrograde movement and delivery of actin patches/endosomes to FM4-64–labeled internal compartments.
Localized Ras signaling at the leading edge regulates PI3K, cell polarity, and directional cell movement
Authors: Sasaki Atsuo T. , Chun Cheryl , Takeda Kosuke , Firtel Richard A.
Published: November 2004

During chemotaxis, receptors and heterotrimeric G-protein subunits are distributed and activated almost uniformly along the cell membrane, whereas PI(3,4,5)P3, the product of phosphatidylinositol 3-kinase (PI3K), accumulates locally at the leading edge. The key intermediate event that creates this strong PI(3,4,5)P3 asymmetry remains unclear. Here, we show that Ras is rapidly and transiently activated in response to chemoattractant stimulation and regulates PI3K activity. Ras activation occurs at the leading edge of chemotaxing cells, and this local activation is independent of the F-actin cytoskeleton, whereas PI3K localization is dependent on F-actin polymerization. Inhibition of Ras results in severe defects in directional movement, indicating that Ras is an upstream component of the cell's compass. These results support a mechanism by which localized Ras activation mediates leading edge formation through activation of basal PI3K present on the plasma membrane and other Ras effectors required for chemotaxis. A feedback loop, mediated through localized F-actin polymerization, recruits cytosolic PI3K to the leading edge to amplify the signal.
A polyalanine tract expansion in Arx forms intranuclear inclusions and results in increased cell death
Authors: Nasrallah Ilya M. , Minarcik Jeremy C. , Golden Jeffrey A.
Published: November 2004

A growing number of human disorders have been associated with expansions of a tract of a single amino acid. Recently, polyalanine (polyA) tract expansions in the Aristaless-related homeobox (ARX) protein have been identified in a subset of patients with infantile spasms and mental retardation. How alanine expansions in ARX, or any other transcription factor, cause disease have not been determined. We generated a series of polyA expansions in Arx and expressed these in cell culture and brain slices. Transfection of these constructs results in nuclear protein aggregation, filamentous nuclear inclusions, and an increase in cell death. These inclusions are ubiquitinated and recruit Hsp70. Coexpressing Hsp70 decreases the percentage of cells with nuclear inclusions. Finally, we show that expressing mutant Arx in mouse brains results in neuronal nuclear inclusion formation. Our data suggest expansions in one of the ARX polyA tracts results in nuclear protein aggregation and an increase in cell death; likely underlying the pathogenesis of the associated infantile spasms and mental retardation.
Enterprise partner selection for vocational education: analytical network process approach
Authors: Hua Chen Sheu , Tso Lin Hung , Tau Lee Hong
Published: November 2004

One of the major purposes of implementing vocational education is to offer trained manpower to enterprises that meet the immense challenges of the global economic competition and unprecedented technological changes. Selecting an adequate enterprise, from the school's viewpoint, is a critical factor for implementing the vocational education system. This paper suggests applying the ANP approach in order to deal with the interdependence among criteria of different layers of the analysis process to select the suitable partner enterprise where students can gain experience. The paper describes the cooperation patterns between schools and enterprises as well as the criteria which should be considered and the corresponding attributes used to evaluate the potential enterprises.
The valuation of intangibles for hotel investments
Authors: Roubi Sherif
Published: November 2004

Reviews the literature on the valuation of intangibles for hotel investments. Contrary to the sceptical outlook portrayed in the literature, demonstrates the effectiveness of ex‐post models and hedonic pricing models (HPM) as an objective and robust tool in separating and measuring intangible hotel property and decomposing total asset value. Develops two HPM models using data on 50 hotel properties appraised in 1997. All hotels are owned and managed by the same hotel company and affiliated with the same brand. Some 58 per cent of the properties are freeholds and the rest are leaseholds. Estimates the hedonic price equations by regressing appraised values on physical, location and economic characteristics of the properties. Results confirm the effectiveness of HPM and in fact its relative superiority to traditional ex‐ante modelling in measuring and decomposing intangible property. As expected at the outset, comparable‐leases and excess‐profits‐based models produced similar results.
kth‐order Markov chain‐based approximation of the Shannon entropy of Gaussian photon‐counting processes
Authors: Kochel Bonawentura
Published: November 2004

A method for approximation of the Shannon entropy of Gaussian photon‐counting processes with infinite history was constructed on the memory function of these processes, described by autoregressive‐integrated moving average (ARIMA) models. Most frequently, photon‐counting processes are stationary or nonstationary multidimensional Gaussian discrete‐time stochastic ones which justify the use of the ARIMA models. Starting from the memory function, a memory time‐equivalent finite autoregressive representation of a given process with infinite history, i.e. a stationary finite‐order Gaussian Markov chain, was determined, then corresponding autocorrelation matrices were calculated from the truncated memory function using the Yule‐Walker equations, and an autocorrelation‐based formula for approximation of the entropy of the process through the entropy of its stationary Markovian representation was given. An ARMA(1,1) process together with its stationary (MA(1)) or nonstationary (IMA(0,1,1)) boundary cases were considered to demonstrate opposite changes in the entropy as the memory time increases at a fixed variance of the process: the entropy was found to decrease for stationary processes and increase for nonstationary ones. It was also found on experimental examples (perturbed human neutrophils and yeast cells) that those changes can be reversed by opposite changes in the process variance. The method allows us to determine, at any desired accuracy, the Shannon entropy of time‐discrete stochastic processes, and reveals new aspects of the relationship between the process' stationarity, memory, entropy and heteroskedasticity.
Employment of different turbulence models to the design of optimum steel flows in a tundish
Authors: Jha Pradeep K. , Dash Sukanta K.
Published: November 2004

The Navier‐Stokes equation and the species continuity equation have been solved numerically in a boundary fitted coordinate system comprising the geometry of a large scale industrial size tundish. The solution of the species continuity equation predicts the time evolution of the concentration of a tracer at the outlets of a six strand billet caster tundish. The numerical prediction of the tracer concentration has been made with six different turbulence models (the standard k‐ε, the k‐ε RNG, the Low Re number Lam‐Bremhorst model, the Chen‐Kim high Re number model (CK), the Chen‐Kim low Re number model (CKL) and the simplest constant effective viscosity model (CEV)) which favorably compares with that of the experimental observation for a single strand bare tundish. It has been found that the overall comparison of the k‐ε model, the RNG, the Lam‐Bremhorst and the CK model is much better than the CKL model and the CEV model as far as gross quantities like the mean residence time and the ratio of mixed to dead volume are concerned. However, the k‐ε model predicts the closest value to the experimental observation compared to all other models. The prediction of the transient behavior of the tracer is best done by the Lam‐Bremhorst model and then by the RNG model, but these models do not predict the gross quantities that accurately like the k‐ε model for a single strand bare tundish. With the help of the above six turbulence models mixing parameters such as the ratio of mix to dead volume and the mean residence time were computed for the six strand tundish for different outlet positions, height of advanced pouring box (APB) and shroud immersion depth. It was found that three turbulence models show a peak value in the ratio of mix to dead volume when the outlets were placed at 200 mm away from the wall. An APB was put on the bottom of the tundish surrounding the inlet jet when the outlets were kept at 200 mm away from the wall. It was also found that there exists an optimum height of the APB where the ratio of mix to dead volume and the mean residence time attain further peak values signifying better mixing in the tundish. At this optimum height of the APB, the shroud immersion depth was made to change from 0 to 400 mm. It was also observed that there exists an optimum immersion depth of the shroud where the ratio of mix to dead volume still attains another peak signifying still better mixing. However, all the turbulence models do not predict the same optimum height of the APB and the same shroud immersion depth as the optimum depth. The optimum height of the APB and the shroud immersion depth were decided when two or more turbulence models predict the same values.
Diaries in health promotion research: the Mobile Information Bus evaluation
Authors: Wyness Laura , Douglas Flora , van Teijlingen Edwin
Published: November 2004

This paper discusses the use of diary‐keeping as part of an evaluation of a complex, community‐based health promotion initiative, using the Mobile Information Bus (MIB) as an example. The MIB was designed to provide health and related information for living adolescents in rural areas of Northeast Scotland. The general strengths and limitations of diary‐keeping as a research method are discussed alongside an account of the evaluators' experiences of using this method within the MIB context, as well as suggestions for improving the efficacy of diary‐keeping as a research method. In addition, the results of an extensive literature search on the topic of diaries as a research method are reported. As part of the MIB evaluation, the diary provided a contemporaneous, in‐depth account of the intervention in operation. Those engaged in evaluation of similar types of projects (particularly related to process evaluation) may find the use of a project diary a useful adjunct to other research methods.
The search for meaning and career development
Authors: Schultze George , Miller Carol
Published: November 2004

This article discusses the importance of existential meaning in career counseling, provides a case study of its application, and relates it to career development theory. Career development and counseling professionals will find existential analysis useful in their service to others. Using logotherapy, a counseling professional living in a pluralistic society can assist individuals with distinct worldviews in their search for meaning. Given our lives and careers, we can find meaning by creating something or doing some good, by experiencing something or someone, and by our attitude towards unavoidable suffering.
Knowledge management as enabling R&D innovation in high tech industry: the case of SAIT
Authors: Suh Woojong , Derick Sohn J.H. , Yeon Kwak Jun
Published: November 2004

The purpose is to present a knowledge management model for R&d organizations and discuss how to employ it for their innovation. This paper first derives generic elements for effective KM implementation through literature reviews. Then, considering the elements, this paper develops an integrative KM model for enabling R&D innovation. Next, this paper analyzes the case of Samsung Advanced Institute of Technology (SAIT), which has performed KM‐based innovation activities on the basis of the model presented in this paper. Finally, this paper discusses the lessons and implications from SAIT’s knowledge management initiatives. To achieve KM‐based innovation successfully in an R&D organization, its generic characteristics should be considered essentially in designing KM activities. From the case analysis of SAIT KM which employs this perspective, the following critical success factors are found: KM measurements metrics to stimulate a strong relationship between KM activities and the organization’s competitiveness, knowledge templates to enable the consistent management of core knowledge, various information group activities to generate meaningful new ideas, and IT systems and rules to satisfy researchers’ individual aspiration for self development. The research limitations/implications are that to generalize the usefulness of the proposed model, more cases need to be analyzed. The practical implications are that the proposed R&D KM model and analyses on the real‐life KM case of SAIT may be employed as significant benchmarking information in other R&D organizations. This paper presents an integrative KM model considering the generic features of R&D organizations.
Managing knowledge: the link between culture and organizational learning
Authors: Pérez López Susana , Manuel Montes Peón José , José Vázquez Ordás Camilo
Published: November 2004

Aims to analyze how the organizational culture impacts knowledge management, organizational learning and ultimately the performance of the firm. The degree to which collaborative culture influences organizational learning and performance is investigated for 195 Spanish firms. The technique used was structural equation modeling (SEM). The results show, first of all, that collaborative culture encourages the development of organizational learning, which at the same time, has a significant effect on business performance. And, second, it is highlighted that collaborative culture does not constitute in itself a source of competitive advantages. Collaborative culture must modify, through learning, the organization’s guidelines and attitudes in order to improve competitive performance. Perhaps the most significant limitation of the study is associated with the use of cross‐sectional data. While we presented and tested models in which we assumed a causal flow from collaborative culture to organizational learning to organizational performance, there is the possibility that these relationships may occur in reverse order. In future researches it would be interesting to analyze the influence that other variables, such organizational structure, leadership and corporate strategy have on learning. The establishment of a knowledge strategy can be determined by a global approach, which affects all fields in organization. For knowledge management initiatives to be truly effective must take into account the social contexts in which learning take place. Culture need to be re‐examined in light of its role in managing the overall organizational learning infrastructure. This study provides empirical evidence for the hypothesis that collaborative culture influences organizational learning which in turn influences business performance. The current study provides some understanding of the manner in which collaborative culture influence organizational outcomes.
Knowledge sharing in context: the influence of organizational commitment, communication climate and CMC use on knowledge sharing
Authors: van den Hooff Bart , de Ridder Jan A.
Published: November 2004

Determining which factors promote or impede the sharing of knowledge within groups and organizations constitutes an important area of research. This paper focuses on three such influences: “organizational commitment,” “organizational communication,” and the use of a specific instrument of communication – computer‐mediated communication (CMC). Two processes of knowledge sharing are distinguished: donating and collecting. A number of hypotheses are presented concerning the influence of commitment, climate and CMC on these processes. These hypotheses were tested in six case studies. The results suggest that commitment to the organization positively influences knowledge donating, and is in turn positively influenced by CMC use. Communication climate is found to be a key variable: a constructive communication climate was found to positively influence knowledge donating, knowledge collecting and affective commitment. Finally, a relationship was found that was not hypothesized: knowledge collecting influences knowledge donating in a positive sense – the more knowledge a person collects, the more he or she is willing to also donate knowledge to others. Based on these results, a number of theoretical and practical implications are discussed, and suggestions for further research are presented.
LEARNING WITH PIECE-WISE LINEAR NETWORKS
Authors: STALEY MARK
Published: November 2004

A new feedforward architecture is presented for empirical model building and regression. The network consists of two hidden layers of units, where each unit utilizes a piece-wise linear activation function. A procedure for determining both the number of units and their connectivity is developed. The most notable feature of the network is its associated learning algorithm which allows for recursive updating of the parameters. A smoothness constraint is employed to limit the range of solutions, so that practical models may be built with small amounts of data. The network is applied to some function estimation tasks, as well as to a forecasting problem using data from the Santa Fe Institute time-series competition.
FUZZY NEURAL NETWORKS: BETWEEN FUNCTIONAL EQUIVALENCE AND APPLICABILITY
Authors: HALGAMUGE SAMAN K. , GLESNER MANFRED
Published: November 2004

Research in fuzzy neural networks, which started from application oriented fuzzy system tuning, then moving to the automatic generation of fuzzy systems from data, is reaching a more mature stage, especially after the proof of functional equivalence of certain fuzzy models and neural networks. It is essential that the applicability of such developments is explored emphasizing the directions that research should follow. It can be shown that the nearest prototype classifier is functionally equivalent to an alternative fuzzy classifier model. Efficient, hardware friendly training algorithms are developed for dynamic generation of an optimum number of nearest prototypes for neural classifiers which enable the generation of fuzzy systems in real time. These systems are tested with complex applications showing the simulation results.
ADAPTIVE FUZZY CONTROL OF UNSTABLE NONLINEAR SYSTEMS
Authors: LIN CHENG-JIAN , LIN CHIN-TENG
Published: November 2004

This paper addresses the structure and an associated on-line learning algorithm of a feedforward multilayer connectionist network for realizing the basic elements and functions of a traditional fuzzy logic controller. The proposed Fuzzy Adaptive Learning Control Network (FALCON) can be contrasted with the traditional fuzzy logic control systems in their network structure and learning ability. An on-line structure/parameter learning algorithm, called FALCON-ART, is proposed for constructing the FALCON dynamically. The FALCON-ART can partition the input/output space in a flexible way based on the distribution of the training data. Hence it can avoid the problem of combinatorial growing of partitioned grids in some complex systems. It combines the backpropagation learning scheme for parameter learning and the fuzzy ART algorithm for structure learning. More notably, the FALCONART can on-line partition the input/output spaces, tune membership functions, and find proper fuzzy logic rules dynamically without any a priori knowledge or even any initial information on these. The proposed learning scheme has been successfully used to control two unstable nonlinear systems. They are the seesaw system and the inverted wedge system.
HUMAN CHROMOSOME CLASSIFICATION USING MULTILAYER PERCEPTRON NEURAL NETWORK
Authors: LERNER B. , GUTERMAN H. , DINSTEIN I. , ROMEM Y.
Published: November 2004

A multilayer perceptron (MLP) neural network (NN) has been studied for human chromosome classification. Only 10–20 examples were required for the MLP NN to reach its ultimate performance classifying chromosomes of 5 types. The empirical dependence of the entropic error on the number of examples was found to be highly comparable to the 1/t function. The principal component analysis (PCA) was used, both for network initialization and for feature reduction purposes. The PCA demonstrated the importance of retaining most of the image information whenever small training sets are used. The MLP NN classifier outperformed the Bayes piecewise classifier for all the cases tested. The MLP classifier was found to be almost unsusceptible to the ratio of the number of training vectors to the number of features, whereas the piecewise classifier was highly dependent on this ratio.
COMPARISON OF MULTILAYER NEURAL NETWORK AND NEAREST NEIGHBOR CLASSIFIERS FOR HANDWRITTEN DIGIT RECOGNITION
Authors: YAN HONG
Published: November 2004

The basic Nearest Neighbor Classifier (NNC) is often inefficient for classification in terms of memory space and computing time needed if all training samples are used as prototypes. These problems can be solved by reducing the number of prototypes using clustering algorithms and optimizing the prototypes using a special neural network model. In this paper, we compare the performance of the multilayer neural network and an Optimized Nearest Neighbor Classifier (ONNC) for handwritten digit recognition applications. We show that an ONNC can have the same recognition performance as an equivalent neural network classifier. The ONNC can be efficiently implemented using prototype and variable ranking, partial summation and distance triangular inequality based strategies. It requires the same memory space as, but less, training time and classification time than the neural network.
REACTION–DIFFUSION PROCESSES ON RANDOM AND SCALE-FREE NETWORKS
Authors: BANERJEE SUBHASIS , MALLICK SHRESTHA BASU , BOSE INDRANI
Published: November 2004

We study the discrete Gierer–Meinhardt model of reaction–diffusion on three different types of networks: regular, random and scale-free. The model dynamics lead to the formation of stationary Turing patterns in the steady state in certain parameter regions. Some general features of the patterns are studied through numerical simulation. The results for the random and scale-free networks show a marked difference from those in the case of the regular network. The difference may be ascribed to the small world character of the first two types of networks.
CELLULAR AUTOMATA CRYPTOGRAPHIC MODEL BASED ON BI-DIRECTIONAL TOGGLE RULES
Authors: OLIVEIRA G. M. B. , COELHO A. R. , MONTEIRO L. H. A.
Published: November 2004

Cellular automata (CA) are discrete dynamical systems that can be employed as cryptography algorithms. Irreversible CA with toggle rules — either to the right or to the left — were already proposed for encrypting. However, the similarity between ciphertexts when the plaintext is submitted to a small perturbation was identified as a flaw in this model. Here, such a model is altered by using bi-directional toggle CA rules instead of one-directional ones. Numerical experiments showed that the similarity flaw was eliminated by considering this modification, obtaining protection against differential cryptanalysis.
TESTING THE DYNAMICS OF HIGH ENERGY SCATTERING USING VECTOR MESON PRODUCTION
Authors: ENBERG RIKARD
Published: November 2004

I review work on diffractive vector meson production in photon–proton collisions at high energy and large momentum transfer, accompanied by proton dissociation and a large rapidity gap. This process provides a test of the high energy scattering dynamics, but is also sensitive to the details of the treatment of the vector meson vertex.

The emphasis is on the description of the process by a solution of the non-forward BFKL equation, i.e. the equation describing the evolution of scattering amplitudes in the high-energy limit of QCD. The formation of the vector meson and the nonperturbative modeling needed is also briefly discussed.
ONE-DIMENSIONAL STATISTICAL MECHANICS FOR IDENTICAL PARTICLES: THE CALOGERO AND ANYON CASES
Authors: DASNIÈRES DE VEIGY ALAIN , OUVRY STÉPHANE
Published: November 2004

The thermodynamic of particles with intermediate statistics interpolating between Bose and Fermi statistics is addressed in the simple case where there is one quantum number per particle. Such systems are essentially one-dimensional. As an illustration, one considers the anyon model restricted to the lowest Landau level of a strong magnetic field at low temperature, the generalization of this model to several particles species, and the one-dimensional Calogero model. One reviews a unified algorithm to compute the statistical mechanics of these systems. It is pointed out that Haldane's generalization of the Pauli's principle can be deduced from the anyon model in a strong magnetic field at low temperature.
THE SKYRMION LIMIT OF THE NAMBU–JONA-LASINIO SOLITON
Authors: ZÜCKERT U. , ALKOFER R. , REINHARDT H. , WEIGEL H.
Published: November 2004

The special role of the isoscalar mesons (σ and ω) in the NJL soliton is discussed. Stable soliton solutions are obtained when the most general ansatz compatible with vanishing grand spin is assumed. These solutions are compared to soliton solutions of a purely pseudoscalar Skyrme type model which is related to the NJL model by a gradient expansion and the limit of infinitely heavy (axial-) vector mesons.
OPERATOR GAUGE TRANSFORMATION AND THE WESS–ZUMINO TERM
Authors: BELVEDERE L. V. , ROTHE K. D.
Published: November 2004

We discuss the generation of the Wess–Zumino term in the chiral Schwinger model via an operator-valued gauge transformation of its gauge noninvariant formulation. Furthermore, the completely fermionized version of the gauge-invariant formulation of this model for a general value of the JR parameter is shown to be equivalent to a generalized chiral Schwinger model including a Thirring interaction.
MODEL FOR EFFICIENT MONOPOLE ANNIHILATION AND BARYOGENESIS
Authors: MOHAN SUBIR
Published: November 2004

We present a model for efficient annihilation of magnetic monopoles which is accomplished by breaking the electromagnetic gauge invariance for an appropriate range of temperature during the radiation dominated epoch of the early universe. Except for the brief period when electromagnetism is broken, the gauge-group symmetry is SU (3)c × SU (2)L × U (1)Y between the grand unification and electroweak transition temperature scales. The model consists of a standard Higgs doublet, a charged singlet and an uncharged singlet, and it is shown to work for a very general set of parameters with none of the scalar coupling constants being, necessarily, either too large or too small. The uncharged singlet can easily give adequately large Majorana mass to the right-handed neutrinos making baryogenesis possible through the decay of heavy right-handed neutrinos and sphaleron interactions.
TQFT VERSUS RCFT: 3-D TOPOLOGICAL INVARIANTS
Authors: BRODA BOGUSŁAW
Published: November 2004

A straightforward relationship between the two approaches to three-dimensional topological invariants, one of them put forward by Witten in the framework of topological quantum field theory, and the second one proposed by Kohno in terms of rational conformal field theory, is established.
MODULAR SYMMETRIES, THRESHOLD CORRECTIONS AND MODULI FOR ℤ2 × ℤ2 ORBIFOLDS
Authors: BAILIN D. , LOVE A. , SABRA W. A. , THOMAS S.
Published: November 2004

ℤ2 × ℤ2 Coxeter orbifolds are constructed with the property that some twisted sectors have fixed planes for which the six-torus cannot be decomposed into a direct sum T2 ⊕ T4 with the fixed plane lying in T2. The string loop threshold corrections to the gauge coupling constants are derived, and display symmetry groups for the T and U moduli that are subgroups of the full modular group PSL(2, ℤ). The effective potential for duality invariant gaugino condensate in the presence of hidden sector matter is constructed and minimized for the values of the moduli. The effect of Wilson lines on the modular symmetries is also studied.
ON SOME CRITICAL PARAMETERS OF HEAVY QUARK MESONS IMMERSED IN QUARK–GLUON PLASMA
Authors: CHAKRABARTI B. , BHATTACHARYA A. , REMADEVI T. L. , BANERJEE S. N.
Published: November 2004

The critical values of the screening parameters, binding radii of Ψ and ϒ mesons embedded in quark–gluon plasma have been estimated when the screened interaction is represented by the Hulthen potential and an appreciable suppression of J/Ψ has also been observed.
DEFORMATION QUANTIZATION OF THE ISOTROPIC ROTATOR
Authors: STERN A. , YAKUSHIN I.
Published: November 2004

We perform a deformation quantization of the classical isotropic rigid rotator. The resulting quantum system is not invariant under the usual SU (2) × SU (2) chiral symmetry, but instead [Formula: see text]. We give the energy spectrum for the resulting system.
THE QUANTUM ALGEBRAIC STRUCTURE OF THE TWISTED XXZ CHAIN
Authors: MONTEIRO M. R. , RODITI I. , RODRIGUES L. M. C. S. , SCIUTO S.
Published: November 2004

We consider the quantum inverse scattering method with a new R-matrix depending on two parameters q and t. We find that the underlying algebraic structure is the two-parameter deformed algebra SU q,t(2) enlarged by introducing an element belonging to the center. The corresponding Hamiltonian describes the spin-1/2 XXZ model with twisted periodic boundary conditions.
QUANTUM FIELD THEORY OF A DISSIPATIVE SYSTEM
Authors: BHATTACHARYA B. , HAJRA K.
Published: November 2004

Quantum dissipative scalar and fermionic fields are studied here from classical stochastic fields. These classical stochastic fields are the outcome of the relativistic generalization of Nelson's stochastic mechanics based on a new microlocal geometry. Results show that the dissipation is the external classical phenomena whereas quantum nature comes from within (microlocal structure).
GRADED ALGEBRA AND NONCOMMUTATIVE GEOMETRY VERSION TO L–R SYMMETRIC MODEL
Authors: BENAOUM H. B.
Published: November 2004

A left–right symmetric model based on graded Lie algebra and noncommutative geometry is constructed. In this approach, the two Higgs fields H R and H L — responsible for the first stage symmetry breaking — transform as [Formula: see text] and [Formula: see text] under SU (2) L , SU (2) R and U(1). Their vacuum expectation values happen to be equal. A bi-doublet ɸ with zero U(1) charge for the second stage is also obtained. Enlarging the Higgs sector with the introduction of the triplets <δ L,R > and singlet <δ0> make parity spontaneously broken at a mass higher than that of the standard charged gauge boson. A fixed value for the Weinberg angle [Formula: see text] and a simple relation between neutral gauge bosons masses [Formula: see text] are predicted.
LATTICE ELECTRONS IN CONSTANT MAGNETIC FIELD: BETHE LIKE ANSATZ
Authors: HAKOBYAN T. , SEDRAKYAN A.
Published: November 2004

We use the functional representation of Heisenberg–Weyl group and obtain equation for the spectrum of the model, which is more complicated than the Bethe ones, but can be written explicitly through theta functions.
ON THE HEISENBERG INDETERMINACY PRINCIPLE AND THE FORMATION OF STRUCTURE IN THE UNIVERSE
Authors: POLLOCK M. D.
Published: November 2004

The Heisenberg indeterminacy principle ΔpaΔqa ~ ħ, relating canonically conjugate variables pa and qa, is quantified for the classical action obtained by the reduction of the ten-dimensional heterotic superstring theory to four dimensions, in the mini-superspace (Friedmann space-time) [Formula: see text]. There are two coordinates, α and [Formula: see text], representing position and velocity, respectively, the canonical momenta being [Formula: see text] and [Formula: see text]. In both cases, the result can be expressed as an indeterminacy in the time, (Δt/t)2. The fluctuations connecting position and velocity decrease with time and are always undetectably small, Δt/t ≲ 10−44. But the fluctuations involving velocity and acceleration increase with time, and are evaluated at the time te of equipartition of radiation and matter in the universe. Translated first into a metric fluctuation [Formula: see text], this is equivalent to a Gaussian, scale-invariant spectrum of density fluctuations of magnitude [Formula: see text], where the dimensionless constant B depends only on the compactification scheme. For a Calabi–Yau internal space, the estimate B ≈ 3 implies that ζ ≈ 2 × 10−4, which is sufficient for the creation of galaxies and in approximate agreement with observations of the anisotropy of the cosmic microwave background radiation by COBE and at Tenerife.
OSCILLATTONS AND STRANGE STARS
Authors: AQUILANO ROBERTO O. , CERVILLERA LUIS P. NEIRA , VUCETICH HÉCTOR
Published: November 2004

We present a model of a remnant of supernova, with a strange matter star, and in this state we introduce radial oscillations. We obtain a strange-pulsar with millisecond oscillations.
CONFORMAL FACTOR DYNAMICS IN THE 1/N EXPANSION
Authors: ELIZALDE E. , ODINTSOV S. D.
Published: November 2004

We suggest to consider conformal factor dynamics as applying to composite bound states, in the framework of the 1/N expansion. In this way, a new model of effective theory for quantum gravity is obtained. The renormalization group (RG) analysis of this model provides a framework to solve the cosmological constant problem, since the value of this constant turns out to be suppressed, as a result of the RG contributions. The effective potential for the conformal factor is also found.
ON THE CORRELATIONS OF MASSES AND LIFETIMES OF RADIONUCLIDES AND FUNDAMENTAL PARTICLES
Authors: RAMANNA RAJA , SREEKANTAN B. V.
Published: November 2004

We show that for unstable fundamental particles and β and α emitting nuclides the product of mass M (ergs) and lifetime T (seconds) can be expressed by the quantized form MT = ħ(2n/n) where n is an integer. The lifetime T is then expressible in the form T = (ħ/M)en/λ, where λ in the case of fundamental particles is a function of "n" only. In the case of β-emitters the mass M is that of the nucleon and in the case of α-emitters, the mass is equivalent to the binding energy of the nucleus. The log T vs n plots for the fundamental particles separate them out according to their flavor. The Heisenberg energy spread relation for decay can be written in the form ΔE = M(n/2n) shows the connection between the rest mass and lifetime through n. The ranges of n values indicate the strength of interaction during decay; n < 10 — strong, n = 10−30 — electromagnetic and "hidden strong" and n > 40 — weak. On this basis we set a lower limit of 6 × 10−21 s for the weak decay of the top quark (mass ~174 GeV).

Some interesting mathematical properties of the functional form n/2n which is the backbone of the present analysis are discussed at the end of the paper.
COSMOLOGICAL CONSTANT IN LOW ENERGY d = 4 STRING LEADS TO (STATIC SPHERICALLY SYMMETRIC) NAKED SINGULARITY
Authors: KALYANA RAMA S.
Published: November 2004

In the sigma model approach, the β-function equations for noncritical strings contain a term which acts like a tree level cosmological constant, Λ. We analyze the static, spherically symmetric solutions to these equations in d = 4 space-time, which will describe the gravitational field of a point star up to a distance r*, of the order of parsecs. We show that the curvature scalar seen by the strings is singular in these solutions if Λ ≠ 0. This singularity is naked. Requiring its absence up to a distance r* imposes the constraint [Formula: see text] in natural units. Thus if r* ≃ 1 Mpc then |Λ| < 10−114, and if r* extends all the way up to the edge of the universe (1028 cm) then |Λ| < 10−122 in natural units. From another point of view, our analysis implies that low energy d = 4 noncritical strings in the sigma model formulation lead to naked singularities.
VOLKOV'S ALGEBRA AND CASIMIR ELEMENT OF SL2
Authors: KRYUKOV SERGEI V.
Published: November 2004

We construct 3-D module of sl 2 and then obtain the generator of classical Volkov's algebra as Casimir element of sl 2. Only classical level is discussed.
LAUGHLIN STATES ON THE SPHERE AS REPRESENTATIONS OF ${\mathcal U}_q({\rm sl}2))$
Authors: AIZAWA NARUHIKO , SACHSE SEBASTIAN , SATO HARU-TADA
Published: November 2004

We discuss quantum algebraic structures of the systems of electrons or quasiparticles on a sphere on whose center a magnetic monopole is located. We verify that the deformation parameter is related to the filling ratio of the particles in each case.