bluuebunny/crossref_metadata_2025_split huggingface dataset:
Augmented Space Formalism for Diagonal and Off‐Diagonal Disordered Alloys
Authors: Cordelli A. , Grosso G. , Parravicini G. Pastori 
Published: July 2007

AbstractA general treatment for electronic states of disordered alloys, including composition‐dependent off‐diagonal Hamiltonian matrix elements is presented. The recursion method within the augmented space of a disordered lattice is exploited. The main novelty is the simple description of the states of this space by a binary logic to allow a manageable use of recurrence relations. Several examples of one‐dimensional disordered alloys are considered, and comparison is performed between the electronic structure obtained with our procedure and numerical simulation of small clusters.
A Numerical Analysis of the Thermal Conductivity in the ab‐Plane of YBa2Cu3O7‐δ
Authors: Eversmann K. , Kopte T. , Dörr M. , Hegenbarth E. 
Published: July 2007

AbstractMeasurements of the thermal conductivity in the ab‐plane of different YBa2Cu3O7‐δ single crystals in the temperature range 2 K < T < 120 K are presented. The crystals differ in oxygen content and density of defects like point defects and twin boundaries. A numerical analysis of the phonon thermal conductivity is described. It allows to separate the scattering rates for phonons due to the scattering mechanisms being effective in YBa2Cu3O7‐δ. The phonon thermal conductivity is considered only in the range of T < 1/3 Tc and T > Tc, because separation of the electron thermal conductivity from the measured total value is complicated between these two limits. The results of analyzing some crystals provide a useful characterization of the mean densities of defects and show the dependence of the scattering mechanisms on the oxygen content.
Effect of the uniaxial compression on the phase transitions in Sn2P2S6‐type ferroelectrics
Authors: Rizak V. M. , Rizak I. M. , Perechinskii S. I. , Vysochanskii Yu. M. , Slivka V. Yu. 
Published: July 2007

AbstractThe effect of uniaxial compression on the temperature dependences of birefringence and dielectric constant is studied for the proper uniaxial ferroelectrics Sn2P2S6 and Sn2P2Se6. The influences of compression on the ferroelectric phase transition (PT) in Sn2P2S6 and on the PT which restricts the incommensurate (IC) phase in Sn2P2Se6 are compared. The observed variations of PT temperature and IC‐phase range with pressure agree with those calculated in an approximation which takes into account the presence of a tricritical point on the phase diagram of the crystals under study along with the Lifshits point. The variation of the ratio of the rates of PT temperature change for different uniaxial mechanical stresses on the replacement of sulphur by selenium as well as the weak sensitivity of the IC‐phase to compression along the structure modulation axis are found. It is suggested that these manifestations of the anisotropy are related to the special features of the linear interaction of soft optical and acoustic phonon branches.
Crystal anharmonicity in Li(H,D) and Na(H,D) systems
Authors: Islam A. K. M. A. , Haque E. , Azad A. S. 
Published: July 2007

AbstractThe reliability of a recently developed potential model is tested by extending the study to various anharmonic properties, e.g., third and fourth‐order elastic constants, Grüneisen parameters, and the pressure derivatives of second‐order elastic constants of hydrides and deuterides of lithium and sodium. A comparison of the calculated properties with the limited experimental results and other theoretical estimates gives an indication of the applicability of the derived potential in the study of crystal anharmonicity. However, the need for further experimental data is stressed in order to judge clearly the reliability of the present calculations for all the compounds.
Thermal properties of Si and Ge under pressure
Authors: Kagaya H.‐Matsuo , Soma T. 
Published: July 2007

AbstractThermal properties of Si and Ge under pressure are studied theoretically from first principles using the lattice dynamical method developed recently. The volume dependence of the anharmonic coefficient for the specific heat A, defined by C/3Nk = 1 + AT, is calculated. Then, numerical calculations of the anharmonic contributions to the thermal expansion coefficient are performed for Si and Ge.
Reservoir hypothesis for the quantum hall effect
Authors: Raymond A. , Sibari H. 
Published: July 2007

AbstractIt is assumed that in modulation‐doped heterojunctions the 2D electron gas is in thermodynamical equilibrium with an external reservoir. In a quantizing magnetic field energy gaps appear in the density of states of the 2D system. This produces, when the magnetic field B increases, oscillations of the density of the free 2D electrons, because of the transfer of electrons into (and out of) the reservoir. It is shown that these oscillations of N8 induce the formation of plateaus of the Hall resistivity ϱxy with the exact quantization in h/ie2 and vanishing values of the resistivity ϱxx, when the Fermi energy is between Landau levels. The model developed in the triangular well approximation accounts well for the width and shape of the Hall steps and for the ϱxx behaviour in a magnetic field, in a large range of temperatures.
Electrosoliton dynamics in a thermalized chain
Authors: Kadantsev V. N. , Lupichcv L. N. , Savin A. V. 
Published: July 2007

AbstractA numerical study of the electrosoliton dynamics in a thermalized molecular chain with asymmetric electron‐phonon interaction is carried out. The effect of thermal vibrations of the chain molecules is taken into account in terms of classical mechanics. It is shown that electrosoliton in α‐helical protein molecules exists at room temperature (300 K).
Theoretical investigation of the self‐trapped hole in alkali halides. I. Long‐range effects within the model hamiltonian approach
Authors: Kantorovich L. N. , Zapol P. B. 
Published: July 2007

AbstractA small‐radius polaron model of the self‐trapped hole (Vk‐center) in alkali halide crystals is presented. Along with the usual contributions, the electronic polarization is also included in accordance with the electronic polaron theory of Toyozawa. It is shown that the exact solution of the problem within the Landau‐Pekar approximation leads to multi‐hole quantum states accompanied by the relevant electronic and lattice polarizations. As an example the KCl crystal is considered, for which the Vk‐center structure as well as the self‐trapping energy are computed. While solving our equations, the local symmetry of the defect is taken into account allowing us to consider a comparatively spread wave function of the hole. The results obtained demonstrate the importance of chemical‐type interactions within the Vk‐center.
Optical properties of fullerite thin films in the 0.4 to 32 eV energy range
Authors: Guizzetti G. , Marabelli F. , Patrini M. , Capozzi V. , Lorusso G. F. , Minafra A. , Manfredini M. , Milani P. 
Published: July 2007

AbstractThe optical properties of C60 thin films are investigated in the energy range 0.4 to 32 eV using reflectance, transmittance, and ellipsometric spectroscopies. The complex dielectric constant and the associated functions are determined by a combination of photometric and ellipsometric data and by Kramers‐Kronig transformations. Spectral features above the fundamental absorption edge (at ≈ 1.8eV) are related to both one‐electron interband transitions and collective electron effects. A comparison is made with recent results of electron energy loss spectroscopy and of theoretical calculations on the f.c.c. fullerite structure.
Behaviour of the optical indicatrix and small‐angle light scattering in the case of “Devil's Staircase”
Authors: Sveleba S. , Kapustianik V. , Polovinko I. , Bublyk M. , Zhmurko V. 
Published: July 2007

AbstractThe deformation and rotation of the optical indicatrix and the scattering of light in the incommensurate phases which consist of a sequence of phases with superstructures are investigated. The periods of such superstructures are large but commensurate with the period of the crystalline lattice. The values of deformation and rotation of the optical indicatrix are determined on the basis of the analysis of light passed through [N(CH3)4]2FeCl4 and [N(CH3)4]2CuCl4 crystals. The pulsing deformation of the optical indicatrix and its rotation in the commensurate regions are found in the incommensurate phase. It is shown that the investigated scattering of light is connected with the scattering on the phason.
Type‐II GaAs/AlAs superlattices under high excitation
Authors: Boujdaria K. , Scalbert D. , la Guillaume C. Benoit À 
Published: July 2007

AbstractHigh‐intensity photoluminescence data on GaAs/AlAs superlattices and multi‐quantum wells of type‐II at low temperature are reported. The variation with density of the renormalized band gap reveals the competition between the Hartree energy, a consequence of non‐local neutrality, which tends to open the gap and the many‐body effects (mainly exchange). Preliminary analysis for a lot of samples with widely different periods provides a satisfactory fit with the Hartree‐Fock model. The kinetics of luminescence and total decay in the electron‐hole plasma regime is measured. In some samples, a phase transition is observed which is tentatively interpreted in terms of the electron‐hole liquid condensation.
Polarization dependence of the V K edge in VO2 through the phase transition at 68 °C
Authors: Poumellec B. , Cortés R. , Loisy E. , Berthon J. 
Published: July 2007

AbstractX‐ray absorption measurements in the low (pseudo‐rutile) and high (rutile) temperature phases of VO2 are described. Investigations are made versus temperature and polarization. The analysis of the results leads to conclusions concerning the scattering mechanisms at the origin of the pre‐edge, the edge, and the first peak of the edge. Specifically, the angular dependence of the pre‐edge of the monoclinic form is different from the rutile form. A new peak on the edge appears for e ‖ cr at low temperature and the pre‐edge and the first peak appears to be sensitive to the asymmetry of the local environment.
The nonlinear paradigm: Advancing paradigmatic progress in the policy sciences
Authors: Douglas L. 
Published: July 2007

AbstractThis paper responds to Daneke 's call for a new systems paradigm in the policy sciences. The nonlinear paradigm is presented as one perspective that may add to this new paradigm. The nonlinear paradigm explores the complex, uncertain, and sometimes unstable time evolution of nonlinear systems. The paper identifies and examines elements of the nonlinear paradigm that have particular relevance for understanding and contending with policy problems. The lessons learned and the tools utilized by this emerging perspective are presented as a means for furthering paradigmatic progress in the policy sciences.
Main dimensions of human practical directives system
Authors: Lewicka‐Strzalecka Anna 
Published: July 2007

AbstractA hypothesis is made that due to the uncertainty and complexity of the practical inference schemes, the acting subject exerts his/her own system of beliefs about efficient ways of attaining the given goals. These beliefs are termed here: Practical Directives, and their system: Practical Attitude. An attempt was made to reconstruct such a system and its main dimensions. To this end, an instrument was constructed: the Questionnaire of Practical Directives (QPD), which is meant as an operational definition of Practical Attitude. A group of 218 subjects was tested with the aid of QPD and the factor analysis of the results revealed nine factors interpreted as main dimensions of the system of Practical Directives.
Projecting military housing needs with decision support systems
Authors: Forgionne Guisseppi A. 
Published: July 2007

AbstractThe Department of the Army must provide its personnel with acceptable housing within the vicinity of military installations. To achieve this housing goal, the Army must often enter into agreements for the construction of housing or for leasing of existing housing. Any housing construction or leasing request must be accompanied by a Segmented Housing Market Analysis (SHMA), a time‐consuming and costly forecasting process that requires many manual labor tasks. As described elsewhere, a Housing Analysis System (HANS) was developed to support these tasks on a micro computer with very user‐friendly computer programs. Recently, the original version of HANS has been modified and incorporated into a larger computer system now under development. At the heart of both the original and modified systems is a set of econometric and heuristic programming models that deliver the required analyses and evaluations. This paper describes these models, explains how they drive the modified HANS, and presents the results and benefits of the use of the modified computer system.Biographical Sketch — Guisseppi A. Forgionne is Professor of Information Systems at the University of Maryland Baltimore County (UMBC). Professor Forgionne holds a B.S. in Commerce and Finance, an M.A. in Econometrics, an M.B.A., and a Ph.D. in Management Science and Econometrics. He has published 16 books and approximately 70 research articles and consulted for a variety of public and private organizations on decision support systems theory and applications. Dr. Forgionne has also served as department chair at UMBC, Mount Vernon College, and Cal Poly Pomona. He has received several national and international awards for his work.
Relevance, formality, and process: Toward a theory of soft systems practice
Authors: Ledington Paul 
Published: July 2007

AbstractThis paper argues that Relevance, Formality, and Process are themes that form an intellectual structure for making sense of the application of systems methodologies to real‐world problem situations and hence provide a starting point for a theory of soft systems practice. These themes are developed from a consideration of the development and use of Soft Systems Methodology. The core concepts and structure of Soft Systems Methodology are described and then a view of Soft Systems Methodology as a tool for managing inquiry‐based intervention into action‐oriented communities is developed and illustrated. The case studies are then used to explore the themes of relevance, formality, and process and to analyse areas of strength and weakness in Soft Systems Methodology.
The concept of coherence considered as a systems isomorphism
Authors: Wolkowski Zbigniew William 
Published: July 2007

AbstractThe concept of coherence has gained a considerable extension from its primary domain of quantum optics over the last quarter of a century. In particular, it offers the possibility of a new conceptual tool for understanding the living state and of biological systems. Considered as a systems isomorphism, it may represent a significant epistemological contribution.
The effects of strategic decision making structure and computerization on organizational performance
Authors: Hoffman James J. , Carter Nancy M. , Cullen John B. 
Published: July 2007

AbstractFindings indicate that the effects from a manager's decision to computerize operations and change the organization's strategic decision making structure are not immediately felt. These findings support the idea that performance needs to be measured on a long‐term basis rather than on a short‐term basis. The results also suggest that it may be erroneous to evaluate managers strictly on a short‐term basis since the effects from strategic decisions may not be fully felt for one or more years.
Morphodynamics Ergodic Theory of Complex Systems
Authors: Fivaz Roland 
Published: July 2007

AbstractMorphodynamics is a general theory of stationay complex system, such as living systems, or mental and social systems it is based on the thermodynamics of physical systems and built on the same lines. By means of the ergodic hypothesis thermodynamics is known to connect the particle dynamics to the energence of order parameters in the equation of state. In the same way, morphodynamics connects order parameters to the emergence of higher level variables; through recurrent applications of the ergodic hypothesis, a hierarchy of equations of state is established which describes a series of successive levels of organization. The equation support a cogmitiveist interpretation that leads to general principles of evolution: the principles determine thespontaneous and irreversible complexification of systems living in their natural environment.
Criticality Analysis of Mis Architecture
Authors: Gupta M. P. , Sushil  
Published: July 2007

AbstractAbstract The Design of Management Information System (MIS) architecture has been the subject of the first phase of the methodology INFLOS reported in the previous article of the current issue of the journal. Sequel to this is the second phase which deals with the criticality analysis of the MIS architecture. In this, from a design point of view, it is aimed to identify critical decision units in terms of their direct and indirect informational impact on overall MIS. The methodology also facilitates the identification of varying possibility levels of informational interaction among the decision units. The results provide important inputs for systematic physical system design.
The nature of order in complex systems
Authors: Fivaz Roland 
Published: July 2007

AbstractOrder in complex systems is investigated within morphodynamics, a theory of evolution considering such systems as ensembles of selectively adaptable components embedded in a random environment. Accordingly, components are specified by pairs of configurational and functional variables submitted to repulsive and attractive interactions; statistical methods of thermodynamics then apply formally. Many order parameters emerge alternatively in the functional space and in the configurational space: a multi‐levelled hierarchy is built that describes organization among functions as well as order among structures. Morphodynamics shows that such coordinations arise spontaneously in absense of computations or instructions; instead, they are selected on a basis of internal stability that warrants both high performance and subsidiary adaptation to environmental constraints. Examples are discussed concerning biological order and sensori‐motor coordinations.
The individual and the collective in health care: A problem of systems ethics
Authors: Strijbos S. 
Published: July 2007

AbstractOur society seems to be characterized by certain imbalances between the individual and the collective, between people and the organizational‐technical systems they manage. In the health care sector this is reflected for example in the pressing problems concerning the control of costs. To clarify these imbalances they are placed in a broader framework, namely, that of the changing nature of our technical‐industrial societies. The role of systems ethics in solving them is explored.
War, hypercomplexity and computer simulation
Authors: Geeraerts Gustaaf 
Published: July 2007

AbstractThe scientific study of war has not yet shown any indication of a major breakthrough. For such a breakthrough to materialize it is paramount to approach the war phenomenon from a dynamic systems perspective. Perceived from this angle, war is placed in both an evolutionary and systems point of view, specifically implying a vision of war as one aspect of the international political process, connected in various ways with other injurious forms of interaction as serious disputes and low level conflict behavior, but also supportive behavior like trade and co‐operation. War constitutes a ‘normal’ event: no less than other social phenomena, it is the result of different over‐time conjunctures of common underlying behavioral mechanisms and resulting processes of interaction occurring within the higher level system's structure. In view of the ‘hypercomplex’ nature of the concerned dynamics, the development of computer (simulation) models will become essential in the study of war and peace.
Spreadthink: Explaining ineffective groups
Authors: Warfield John N. 
Published: July 2007

AbstractExtended testing of the performance of small groups working with complex issues has revealed the pervasive existence of a phenomenon which is here named ‘Spreadthink’. This phenomenon accounts for worldwide ineffectiveness of groups of people trying to work together to resolve complex issues under conditions that neither recognize nor compensate for Spreadthink.Since Spreadthink is an immobilizing phenomenon, it deserves widespread attention and appropriate compensatory action by leaders, managers and administrators wherever complex issues are under serious consideration in organizations.Concurrent with the testing that uncovered and documented Spreadthink, measures that can be taken to overcome the effects of Spreadthink have been tested. The evidence that would prove the effectiveness of these measures is equal in extent, but much less quantitative in nature than the evidence that supports the presence of Spreadthink. Nevertheless, a significant case can be made to the effect that if Spreadthink can be overcome in a particular situation, the system of management called interactive management provides the capability to overcome it in that situation.
Synergy and self‐organization in the evolution of complex systems
Authors: Corning Peter A. 
Published: July 2007

AbstractSynergy of various kinds has played a significant creative role in evolution; it has been a prodigious source of evolutionary novelty. Elsewhere it has been proposed that the functional (selective) advantages associated with various forms of synergistic phenomena have been an important cause of the ‘progressive’ evolution of complex systems over time. Underlying the many specific steps in the complexification process, a common functional principle has been operative. Recent mathematical modelling work in biology, utilizing a new generation of non‐linear dynamical systems models, has resulted in a radically different hypothesis. It has been asserted that ‘spontaneous’, autocatalytic processes, which are held to be inherent properties of living matter itself, may be responsible for much of the order found in nature and that natural selection is merely a supporting actor. A new ‘physics of biology’ is envisioned in which emerging natural laws of organization will be recognized as being responsible both for driving the evolutionary process and for truncating the role of natural selection. This article describes these two paradigms in some detail and discusses the possible relationship between them. Their relevance to the process of human evolution is also briefly discussed.
A survey of applied systemology
Authors: McNeil Donald H. 
Published: July 2007

AbstractIn recent years there has been an undercurrent of dissatisfaction with conventional, rigid conceptualizations of systems and a growing initiative to supplant them with a more fluid paradigm for a general theory of systemicity. It has been proposed that a properly developed systemology would constitute an applied philosophy, highly relevant to a constructive re‐vision, not only of the sciences but also of human affairs. A homeokinetic paradigm with a heterarchical (toroidal) topology has been recommended as a replacement for linear and hierarchical archetypes of systems.This paper first reintroduces the central concepts of systemology, then offers a survey of some systemological applications under the following subheadings:

•how the idea of systemicity can be reconceived so as to unshackle imagination;
•how systemological theory helps to decode the literature and appraise the discourse about ‘systems’;
•how systemological principles can confirm and/ or debunk cherished beliefs;
•how natural systems can be envisioned whole;
•how artificial systems may be planned and developed felicitously;
•how all systems in general may be better appreciated.