Página 1 dos resultados de 8045 itens digitais encontrados em 0.026 segundos

Dynamics of Systems with Large Number of Degrees of Freedom and Generalized Transformation Theory*

Prigogine, I.; George, C.; Henin, F.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1970 EN
Relevância na Pesquisa
45.84%
A generalized transformation theory which leads to a non-Hamiltonian description of dynamics is introduced. The transformation is such that all averages of observables remain invariant. However, the time evolution of the density matrix can no longer be expressed in terms of a commutator with the Hamiltonian. Therefore such transformations are not canonical in the usual sense. An explicit „two components” representation of the equations of motion is given which has the following properties: (a) each of the components satisfies a separate equation of motion, and (b) one component satisfies a kinetic equation of a generalized Boltzmann type.

Physical Particle Representation and Generalized Transformation Theory

Prigogine, I.; George, Cl.; Henin, F.; Mandel, P.; Turner, J. W.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1970 EN
Relevância na Pesquisa
45.77%
The investigation of the recently described generalized transformation theory which leads to a non-Hamiltonian description of dynamics is pursued. The concept of generalized unitary transformations of superoperators is introduced and a specific class of transformations studied. For nondissipative systems it is equivalent to the usual unitary transformations that diagonalize the Hamiltonian. The important point is that this class of transformations remains meaningful for dissipative systems, hence a new representation of dynamics that we shall call the „physical particle” representation. It has the following properties: (a) The energy (or an arbitrary function of the energy) is represented by a diagonal matrix. (b) In the (0)II space (see these Proceedings, 65, 789 (1970)) corresponding to the coherent processes, the evolution can be described in terms of the changes in population of the physical particles. (c) At thermodynamic equilibrium, the physical particles are uncorrelated and behave as independent entities; the entropy has a purely combinatorial meaning.

2.141 Modeling and Simulation of Dynamic Systems, Fall 2002; Modeling and Simulation of Dynamic Systems

Hogan, Neville John
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
EN-US
Relevância na Pesquisa
45.88%
Mathematical modeling of complex engineering systems at a level of detail compatible with the design and implementation of modern control systems. Wave-like and diffusive energy transmission systems. Multiport energy storing fields and dissipative fields; consequences of symmetry and asymmetry. Nonlinear mechanics and canonical transformation theory. Examples will include mechanisms, electromechanical transducers, electronic systems, fluid systems, thermal systems, compressible flow processes, chemical processes. Description from course home page: This course deals with modeling multi-domain engineering systems at a level of detail suitable for design and control system implementation. Topics covered include network representation, state-space models; multi-port energy storage and dissipation, Legendre transforms, nonlinear mechanics, transformation theory, Lagrangian and Hamiltonian forms and control-relevant properties. Application examples may include electro-mechanical transducers, mechanisms, electronics, fluid and thermal systems, compressible flow, chemical processes, diffusion, and wave transmission.

An exploration of transformation theory and the western tradition: a critical evaluation of a graduate studies class

Clark, Janice E.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
45.88%
This qualitative study is an exploration of transformation theory, the Western tradition, and a critical evaluation of a graduate studies class at a university. It is an exploration of assumptions that are embedded in experience, that influence the experience and provide meaning about the experience. An attempt has been made to identify assumptions that are embedded in Western experience and connect them with assumptions that shape the graduate class experience. The focus is on assumptions that facilitate and impede large group discussions. Jungian psychology of personality type and archetype and developmental psychology is used to analyze the group experience. The pragmatic problem solving model, developed by Knoop, is used to guide thinking about the Western tradition. It is used to guide the analysis, synthesis and writing of the experience of the graduate studies class members. A search through Western history, philosophy. and science revealed assumptions about the nature of truth, reality, and the self. Assumptions embedded in Western thinking about the subject-object relationship, unity and diversity are made explicit. An attempt is made to identify Western tradition assumptions underlying transformation theory. The critical evaluation of the graduate studies class experience focuses upon issues associated with group process...

Perspective Transformation Theory and the Donald Woods Experience: From Racist to Anti-Apartheid Activist

Reid, Merlene V
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
45.77%
This paper chronicles White South African journalist Donald Woods’ life (1933-2001) as he transformed from holding racist beliefs that Blacks were “people who were there to be your servants,” to becoming one of his country’s leading anti-apartheid activists. Adult learning and development via perspective transformation theory are explored.

Sequence Diagrams Integration via Typed Graphs: Theory and Implementation

LIANG, HONGZHI
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 2553268 bytes; application/pdf
EN; EN
Relevância na Pesquisa
36.03%
It is widely accepted within the software engineering community that the support for integration is necessary for requirement models. Several methodologies, such as the role-based software development, that have appeared in the literature are relying on some kind of integration. However, current integration techniques and their tools support are insufficient. In this research, we discuss our solution to the problem. More precisely, we present a general integration approach for scenario-based models, particularly for UML Sequence Diagrams, based on the colimit construction known from category theory. In our approach, Sequence Diagrams are represented by SD-graphs, a special kind of typed graphs. The merge algorithm for SD-graphs is an extension of existing merge operations on sets and graphs. On the one hand, the merge algorithm ensures traceability and guarantees key theoretical properties (e.g., “everything is represented and nothing extra is acquired” during the merge). On the other hand, our formalization of Sequence Diagrams as SD-graphs retains the graphical nature of Sequence Diagrams, yet is amenable to algebraic manipulations. Another important property of our process is that our approach is applicable to other kinds of models as long as they can be represented by typed graphs. A prototype Sequence Diagram integration tool following the approach has been implemented. The tool is not only a fully functional integration tool...

La transformation du rôle de représentante d’aidantes familiales pendant l’hébergement de leur parent atteint de démence : une théorisation ancrée

Legault, Alain
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation Formato: 599523 bytes; application/pdf
FR
Relevância na Pesquisa
36.03%
RÉSUMÉ L‘hébergement en centre de soins de longue durée d'un parent âgé atteint de démence marque une transition pour les personnes qui occupent un rôle d’aidant familial principal. Ces personnes, principalement des femmes, poursuivent leur engagement après l’hébergement et souhaitent être impliquées dans les décisions concernant les soins offerts à leur parent. Souvent l'hébergement survient au moment où la personne âgée n'est plus en mesure, compte tenu de ses déficiences cognitives, d'exprimer clairement ses besoins; les aidantes accordent alors une place centrale au rôle de représentante de leur proche hébergé. Cette étude avait pour but d’expliquer la transformation du rôle de représentante chez des aidantes familiales dont le parent atteint de démence vit dans un centre d’hébergement et de soins de longue durée (CHSLD). La méthode qualitative de la théorisation ancrée a été retenue pour expliquer ce processus social. Les résultats obtenus reposent sur 14 entrevues en profondeur réalisées auprès de filles dont le parent atteint de démence était hébergé depuis plus de six mois dans un CHSLD. Ces aidantes ont été sélectionnées selon une procédure d’échantillonnage théorique et l’analyse des données a été réalisée à partir de la transcription intégrale des entrevues en suivant trois niveaux d'analyse...

General U(N) gauge transformations in the realm of covariant Hamiltonian field theory

Struckmeier, Jürgen; Reichau, Hermine
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.96%
A consistent, local coordinate formulation of covariant Hamiltonian field theory is presented. While the covariant canonical field equations are equivalent to the Euler-Lagrange field equations, the covariant canonical transformation theory offers more general means for defining mappings that preserve the action functional - and hence the form of the field equations - than the usual Lagrangian description. Similar to the well-known canonical transformation theory of point dynamics, the canonical transformation rules for fields are derived from generating functions. As an interesting example, we work out the generating function of type F_2 of a general local U(N) gauge transformation and thus derive the most general form of a Hamiltonian density that is form-invariant under local U(N) gauge transformations.; Comment: 35 pages, Symposium on Exciting Physics: Quarks and gluons/atomic nuclei/biological systems/networks, Makutsi Safari Farm, South Africa, 13-20 November 2011; Exciting Interdisciplinary Physics, Walter Greiner, Ed., FIAS Interdisciplinary Science Series, Springer International Publishing Switzerland, 2013

A canonical transformation theory from extended normal ordering

Yanai, Takeshi; Chan, Garnet Kin-Lic
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 20/07/2007
Relevância na Pesquisa
45.92%
The Canonical Transformation theory of Yanai and Chan [J. Chem. Phys. 124, 194106 (2006)] provides a rigorously size-extensive description of dynamical correlation in multireference problems. Here we describe a new formulation of the theory based on the extended normal ordering procedure of Mukherjee and Kutzelnigg [J. Chem. Phys. 107, 432 (1997)]. On studies of the water, nitrogen, and iron-oxide potential energy curves, the Linearised Canonical Transformation Singles and Doubles theory is competitive in accuracy with some of the best multireference methods, such as the Multireference Averaged Coupled Pair Functional, while computational timings (in the case of the iron-oxide molecule) are two-three orders of magnitude faster and comparable to those of Complete Active Space Second-Order Perturbation Theory. The results presented here are greatly improved both in accuracy and in cost over our earlier study as the result of a new numerical algorithm for solving the amplitude equations.; Comment: 16 pages, 7 figures, to be published in J. Chem. Phys

Right-unitary transformation theory and applications

Tang, Zhong
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/04/1996
Relevância na Pesquisa
45.88%
We develop a new transformation theory in quantum physics, where the transformation operators, defined in the infinite dimensional Hilbert space, have right-unitary inverses only. Through several theorems, we discuss the properties of state space of such operators. As one application of the right-unitary transformation (RUT), we show that using the RUT method, we can solve exactly various interactions of many-level atoms with quantized radiation fields, where the energy of atoms can be two levels, three levels in Lambda, V and equiv configurations, and up to higher (>3) levels. These interactions have wide applications in atomic physics, quantum optics and quantum electronics. In this paper, we focus on two typical systems: one is a two-level generalized Jaynes-Cummings model, where the cavity field varies with the external source; the other one is the interaction of three-level atom with quantized radiation fields, where the atoms have Lambda-configuration energy levels, and the radiation fields are one-mode or two-mode cavities.; Comment: 51 pages, RevTeX; Figures not included but may be obtained from author by snail-mail; Accepted for publication by Phys. Rev. A

Charged Free Fermions, Vertex Operators and Classical Theory of Conjugate Nets

Doliwa, Adam; Manas, Manuel; Alonso, Luis Martinez; Medina, Elena; Santini, Paolo Maria
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 20/03/1998
Relevância na Pesquisa
45.7%
We show that the quantum field theoretical formulation of the $\tau$-function theory has a geometrical interpretation within the classical transformation theory of conjugate nets. In particular, we prove that i) the partial charge transformations preserving the neutral sector are Laplace transformations, ii) the basic vertex operators are Levy and adjoint Levy transformations and iii) the diagonal soliton vertex operators generate fundamental transformations. We also show that the bilinear identity for the multicomponent Kadomtsev-Petviashvili hierarchy becomes, through a generalized Miwa map, a bilinear identity for the multidimensional quadrilateral lattice equations.; Comment: 28 pages, 3 Postscript figures

Polynomial Similarity Transformation Theory: A smooth interpolation between coupled cluster doubles and projected BCS applied to the reduced BCS Hamiltonian

Degroote, Matthias; Henderson, Thomas M.; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/12/2015
Relevância na Pesquisa
55.92%
We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wavefunction. In between, we interpolate using a single parameter. The effective Hamiltonian is non-hermitian and this Polynomial Similarity Transformation Theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1\% across all interaction stengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.

BPS-Saturated Bound States of Tilted P-Branes in Type II String Theory

Behrndt, Klaus; Cvetic, Mirjam
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
35.99%
We found BPS-saturated solutions of M-theory and Type II string theory which correspond to (non-marginally) bound states of p-branes intersecting at angles different from pi/2. These solutions are obtained by starting with a BPS marginally bound (orthogonally) intersecting configurations of two p-branes (e.g, two four-branes of Type II string theory), performing a boost transformation at an angle with respect to the world-volume of the configuration, performing T-duality transformation along the boost-direction, S-duality transformation, and T- transformations along the direction perpendicular to the boost transformation. The resulting configuration is non-marginally bound BPS-saturated solution whose static metric possesses the off-diagonal term which cannot be removed by a coordinate transformation, and thus signifies an angle (different from pi/2) between the resulting intersecting p-branes. Additional new p-branes are bound to this configuration, in order to ensure the stability of such a static, tilted configuration.; Comment: 11 pages, Latex with two postscript figures, minor corrections, version to appear in Phys. Rev. D

The Moyal-Lie Theory of Phase Space Quantum Mechanics

Hakioglu, T.; Dragt, A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/08/2001
Relevância na Pesquisa
45.68%
A Lie algebraic approach to the unitary transformations in Weyl quantization is discussed. This approach, being formally equivalent to the $\star$-quantization, is an extension of the classical Poisson-Lie formalism which can be used as an efficient tool in the quantum phase space transformation theory.; Comment: 15 pages, no figures, to appear in J. Phys. A (2001)

Extended covariance under nonlinear canonical transformation in Weyl quantization

Hakioglu, T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.88%
A theory of nonunitary-invertible as well as unitary canonical transformations is formulated in the context of Weyl's phase space representations. Exact solutions of the transformation kernels and the phase space propagators are given for the three fundamental canonical maps as fractional-linear, gauge and contact (point) transformations. Under the nonlinear maps a phase space representation is mapped to another phase space representation thereby extending the standard concept of covariance. This extended covariance allows Dirac-Jordan transformation theory to naturally emerge from the Hilbert space representations in the Weyl quantization.; Comment: 21 pages, no figures

A Theory of Transformation Monoids: Combinatorics and Representation Theory

Steinberg, Benjamin
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/04/2010
Relevância na Pesquisa
36.08%
The aim of this paper is to develop a theory of finite transformation monoids and in particular to study primitive transformation monoids. We introduce the notion of orbitals and orbital digraphs for transformation monoids and prove a monoid version of D. Higman's celebrated theorem characterizing primitivity in terms of connectedness of orbital digraphs. A thorough study of the module (or representation) associated to a transformation monoid is initiated. In particular, we compute the projective cover of the transformation module over a field of characteristic zero in the case of a transitive transformation or partial transformation monoid. Applications of probability theory and Markov chains to transformation monoids are also considered and an ergodic theorem is proved in this context. In particular, we obtain a generalization of a lemma of P. Neumann, from the theory of synchronizing groups, concerning the partition associated to a transformation of minimal rank.

Cloaks, editors, and bubbles: applications of spacetime transformation theory

Kinsler, Paul; McCall, Martin W.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.91%
Spacetime or `event' cloaking was recently introduced as a concept, and the theoretical design for such a cloak was presented for illumination by electromagnetic waves [McCall, Favaro, Kinsler, Boardman 2011]. Here we describe how event cloaks can be designed for simple wave systems, using either an approximate `speed cloak' method, or an exact full-wave one. Further, we discuss in detail many of the implications of spacetime transformation devices, covering their (usually) directional nature, spacetime distortions (as opposed to cloaks), and how leaky cloaks manifest themselves. We also address more exotic concepts that follow naturally on from considerations of simple spacetime transformation devices, such as spacetime modeling and causality editors; and describe a proposal for implementing the interrupt-without-interrupt concept suggested by McCall et al. We also describe how we might make a simple time-dependent `bubbleverse' by embedding a modulated Maxwell's Fisheye transformation device (T-device) in a flat background spacetime.; Comment: 11 pages, 12 figures (v2 - update fig 6, 7) (v3 - closer to published version) Previously titled "Some thoughts on spacetime transformation theory"

Dualities as symmetries of the Supermembrane Theory

del Moral, M. P. Garcia
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/11/2012
Relevância na Pesquisa
35.99%
In this note I review the role played by dualities in the Supermembrane Theory compactified on a torus. Supermembrane theory realize S, T, so U-duality, as exact symmetries of the theory. There are two well defined sectors: with and without central charges. Both sectors have the SL(2,Z)xZ2 U-duality group in 9D as a symmetry of the theory, but the supermembrane with central charges, also exhibits an extra SL(2,Z) symmetry of the theory associated to the diffeomorphisms not connected with the identity changing the homology basis. The Z2 symmetry is T-duality transformation that acts on the supermembrane and generalize that of the string. This T-duality transformation acts locally and also globally on the supermembrane theory. It has a natural description in terms of the cohomology of the base manifold and the homology of the target torus. When only string-like states are preserved, one recovers both type II string theories in 9D. If one also consider properly limit of the T-duality transformation characterizing the supermembrane, the usual closed string T-duality transformation between the type IIA and type IIB mass operators is recovered.; Comment: 17 pg, latex. arXiv admin note: substantial text overlap with arXiv:1203.2767

Emerging of massive gauge particles in inhomogeneous local gauge transformations: replacement of Higgs mechanism

Struckmeier, Jürgen
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
35.98%
A generalized theory of gauge transformations is presented on the basis of the covariant Hamiltonian formalism of field theory, for which the covariant canonical field equations are equivalent to the Euler-Lagrange field equations. Similar to the canonical transformation theory of point dynamics, the canonical transformation rules for fields are derived from generating functions. Thus---in contrast to the usual Lagrangian description---the covariant canonical transformation formalism automatically ensures the mappings to preserve the action principle, and hence to be {\em physical}. On that basis, we work out the theory of inhomogeneous local gauge transformations that generalizes the conventional local SU(N) gauge transformation theory. It is shown that massive gauge bosons naturally emerge in this description, which thus could supersede the Higgs mechanism.; Comment: 25 pages. arXiv admin note: text overlap with arXiv:0811.0508

The internal consistency of the standard gamble: tests after adjusting for prospect theory

Oliver, Adam
Fonte: London School of Economics and Political Science Research Publicador: London School of Economics and Political Science Research
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em //2003 EN; EN
Relevância na Pesquisa
36.01%
This article reports a study that tests whether the internal consistency of the standard gamble can be improved upon by incorporating loss weighting and probability transformation parameters in the standard gamble valuation procedure. Five alternatives to the standard EU formulation are considered: (1) probability transformation within an EU framework; and, within a prospect theory framework, (2) loss weighting and full probability transformation, (3) no loss weighting and full probability transformation, (4) loss weighting and no probability transformation, and (5) loss weighting and partial probability transformation. Of the five alternatives, only the prospect theory formulation with loss weighting and no probability transformation offers an improvement in internal consistency over the standard EU valuation procedure.