914 resultados para COARSENING PROCESSES (THEORY)


Relevância:

30.00% 30.00%

Publicador:

Resumo:

R-matrix with time-dependence theory is applied to electron-impact ionisation processes for He in the S-wave model. Cross sections for electron-impact excitation, ionisation and ionisation with excitation for impact energies between 25 and 225 eV are in excellent agreement with benchmark cross sections. Ultra-fast dynamics induced by a scattering event is observed through time-dependent signatures associated with autoionisation from doubly excited states. Further insight into dynamics can be obtained through examination of the spin components of the time-dependent wavefunction.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This thesis makes use of the unique reregulation of pharmaceutical monopoly in Sweden to critically examine intraindustry firm heterogeneity. It contributes to existing divestiture research as it studies the dynamism in between reconfigurations of value constellations and its effects on value creation of divested pharmacies. Because the findings showed that the predominant theory of intraindustry firm heterogeneity could not explain firm performance, the value constellation concept was applied as it captured the phenomena. A patterned finding informed how reconfigurations of value constellations in a reregulated market characterized by strict rules, regulations, and high competition did not generate additional value for firms on short term. My study unveils that value creation is hampered in situations where rules and regulations significantly affect firms’ ability to reconfigure their value constellations. The key practical implication is an alternative perspective on fundamental aspects of the reregulation and how policy-makers may impede firm performance and the intended creation of new value for not only firms but for society as a whole.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The last two decades have seen a proliferation of research frameworks that emphasise the importance of understanding adaptive processes that happen at different levels. We contribute to this growing body of literature by exploring how cultural (mal)adaptive dynamics relate to multilevel social-ecological processes occurring at different scales, where the lower levels combine into new units with new organizations, functions, and emergent properties or collective behaviors. After a brief review of the concept of “cultural adaptation” from the perspective of cultural evolutionary theory, the core of the paper is constructed around the exploration of multilevel processes occurring at the temporal, spatial, social, and political scales. We do so by using insights from cultural evolutionary theory and by examining small-scale societies as case studies. In each section, we discuss the importance of the selected scale for understanding cultural adaptation and then present an example that illustrates how multilevel processes in the selected scale help explain observed patterns in the cultural adaptive process. The last section of the paper discusses the potential of modeling and computer simulation for studying multilevel processes in cultural adaptation. We conclude by highlighting how elements from cultural evolutionary theory might enrich the multilevel process discussion in resilience theory.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Les élections post-conflit ou élections de sortie de crise organisées sous l’égide de la communauté internationale en vue de rétablir la paix dans les pays sortant de violents conflits armés ont un bilan mixte caractérisé par le succès ou l’échec selon les cas. Ce bilan mitigé représente le problème principal auquel cette recherche tente de répondre à travers les questions suivantes : l’assistance électorale étrangère est-elle efficace comme outil de rétablissement de la paix dans les sociétés post-conflit? Qu’est ce qui détermine le succès ou l’échec des élections post-conflit à contribuer efficacement au rétablissement de la paix dans les sociétés déchirées par la guerre? Pour résoudre cette problématique, cette thèse développe une théorie de l’assistance électorale en période post-conflit centrée sur les parties prenantes à la fois du conflit armé et du processus électoral. Cette théorie affirme que l’élément clé pour le succès des élections post-conflit dans le rétablissement de la paix est le renforcement de la capacité de négociation des parties prenantes à la fois dans le processus de paix et dans le processus électoral post-conflit. Dans les situations post-conflit, une assistance électorale qui se voudrait complète et efficace devra combiner à la fois le processus électoral et le processus de paix. L’assistance électorale sera inefficace si elle se concentre uniquement sur les aspects techniques du processus électoral visant à garantir des élections libres, transparentes et équitables. Pour être efficace, l’accent devra également être mis sur les facteurs supplémentaires qui peuvent empêcher la récurrence de la guerre, tels que l’habilité des individus et des groupes à négocier et à faire des compromis sur les grandes questions qui peuvent menacer le processus de paix. De fait, même des élections transparentes comme celles de 1997 au Liberia saluées par la communauté internationale n’avaient pas réussi à établir des conditions suffisantes pour éviter la reprise des hostilités. C’est pourquoi, pour être efficace, l’assistance électorale dans les situations de post-conflit doit prendre une approche globale qui priorise l’éducation civique, la sensibilisation sur les droits et responsabilités des citoyens dans une société démocratique, le débat public sur les questions qui divisent, la participation politique, la formation au dialogue politique, et toute autre activité qui pourrait aider les différentes parties à renforcer leur capacité de négociation et de compromis. Une telle assistance électorale fera une contribution à la consolidation de la paix, même dans le contexte des élections imparfaites, comme celles qui se sont détenues en Sierra Leone en 2002 ou au Libéria en 2005. Bien que la littérature sur l’assistance électorale n’ignore guère l’importance des parties prenantes aux processus électoraux post-conflit (K. Kumar, 1998, 2005), elle a fortement mis l’accent sur les mécanismes institutionnels. En effet, la recherche académique et professionnelle est abondante sur la réforme des lois électorales, la reforme constitutionnelle, et le développement des administrations électorales tels que les commissions électorales, ainsi que l’observation électorale et autres mécanismes de prévention de la fraude électorale, etc. (Carothers & Gloppen, 2007). En d’autres termes, les décideurs et les chercheurs ont attribué jusqu’à présent plus d’importance à la conception et au fonctionnement du cadre institutionnel et des procédures électorales. Cette thèse affirme qu’il est désormais temps de prendre en compte les participants eux-mêmes au processus électoral à travers des types d’assistance électorale qui favoriseraient leur capacité à participer à un débat pacifique et à trouver des compromis aux questions litigieuses. Cette approche plus globale de l’assistance électorale qui replace l’élection post-conflit dans le contexte plus englobant du processus de paix a l’avantage de transformer le processus électoral non pas seulement en une expérience d’élection de dirigeants légitimes, mais aussi, et surtout, en un processus au cours duquel les participants apprennent à régler leurs points de vue contradictoires à travers le débat politique dans un cadre institutionnel avec des moyens légaux et légitimes. Car, si le cadre institutionnel électoral est important, il reste que le résultat du processus électoral dépendra essentiellement de la volonté des participants à se conformer au cadre institutionnel et aux règles électorales.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This analysis paper presents previously unknown properties of some special cases of the Wright function whose consideration is necessitated by our work on probability theory and the theory of stochastic processes. Specifically, we establish new asymptotic properties of the particular Wright function 1Ψ1(ρ, k; ρ, 0; x) = X∞ n=0 Γ(k + ρn) Γ(ρn) x n n! (|x| < ∞) when the parameter ρ ∈ (−1, 0)∪(0, ∞) and the argument x is real. In the probability theory applications, which are focused on studies of the Poisson-Tweedie mixtures, the parameter k is a non-negative integer. Several representations involving well-known special functions are given for certain particular values of ρ. The asymptotics of 1Ψ1(ρ, k; ρ, 0; x) are obtained under numerous assumptions on the behavior of the arguments k and x when the parameter ρ is both positive and negative. We also provide some integral representations and structural properties involving the ‘reduced’ Wright function 0Ψ1(−−; ρ, 0; x) with ρ ∈ (−1, 0) ∪ (0, ∞), which might be useful for the derivation of new properties of members of the power-variance family of distributions. Some of these imply a reflection principle that connects the functions 0Ψ1(−−;±ρ, 0; ·) and certain Bessel functions. Several asymptotic relationships for both particular cases of this function are also given. A few of these follow under additional constraints from probability theory results which, although previously available, were unknown to analysts.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This dissertation demonstrates an explanation of damage and reliability of critical components and structures within the second law of thermodynamics. The approach relies on the fundamentals of irreversible thermodynamics, specifically the concept of entropy generation due to materials degradation as an index of damage. All failure mechanisms that cause degradation, damage accumulation and ultimate failure share a common feature, namely energy dissipation. Energy dissipation, as a fundamental measure for irreversibility in a thermodynamic treatment of non-equilibrium processes, leads to and can be expressed in terms of entropy generation. The dissertation proposes a theory of damage by relating entropy generation to energy dissipation via generalized thermodynamic forces and thermodynamic fluxes that formally describes the resulting damage. Following the proposed theory of entropic damage, an approach to reliability and integrity characterization based on thermodynamic entropy is discussed. It is shown that the variability in the amount of the thermodynamic-based damage and uncertainties about the parameters of a distribution model describing the variability, leads to a more consistent and broader definition of the well know time-to-failure distribution in reliability engineering. As such it has been shown that the reliability function can be derived from the thermodynamic laws rather than estimated from the observed failure histories. Furthermore, using the superior advantages of the use of entropy generation and accumulation as a damage index in comparison to common observable markers of damage such as crack size, a method is proposed to explain the prognostics and health management (PHM) in terms of the entropic damage. The proposed entropic-based damage theory to reliability and integrity is then demonstrated through experimental validation. Using this theorem, the corrosion-fatigue entropy generation function is derived, evaluated and employed for structural integrity, reliability assessment and remaining useful life (RUL) prediction of Aluminum 7075-T651 specimens tested.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The analysis of system calls is one method employed by anomaly detection systems to recognise malicious code execution. Similarities can be drawn between this process and the behaviour of certain cells belonging to the human immune system, and can be applied to construct an artificial immune system. A recently developed hypothesis in immunology, the Danger Theory, states that our immune system responds to the presence of intruders through sensing molecules belonging to those invaders, plus signals generated by the host indicating danger and damage. We propose the incorporation of this concept into a responsive intrusion detection system, where behavioural information of the system and running processes is combined with information regarding individual system calls.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Transitions processes in higher education are characterized by new learning situations which pose challenges to most students. This chapter explores the heterogeneity of reactions to these challenges from a perspective of regulation processes. The Integrated Model of Learning and Action is used to identity different patterns of motivational regulation amongst students at university by using mixed distribution models. Six subpopulations of motivational regulation could be identified: students with self-determined, pragmatic, strategic, negative, anxious and insecure learning motivation. Findings about these patterns can be used to design didactic measures that will support students’ learning processes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this dissertation I draw a connection between quantum adiabatic optimization, spectral graph theory, heat-diffusion, and sub-stochastic processes through the operators that govern these processes and their associated spectra. In particular, we study Hamiltonians which have recently become known as ``stoquastic'' or, equivalently, the generators of sub-stochastic processes. The operators corresponding to these Hamiltonians are of interest in all of the settings mentioned above. I predominantly explore the connection between the spectral gap of an operator, or the difference between the two lowest energies of that operator, and certain equilibrium behavior. In the context of adiabatic optimization, this corresponds to the likelihood of solving the optimization problem of interest. I will provide an instance of an optimization problem that is easy to solve classically, but leaves open the possibility to being difficult adiabatically. Aside from this concrete example, the work in this dissertation is predominantly mathematical and we focus on bounding the spectral gap. Our primary tool for doing this is spectral graph theory, which provides the most natural approach to this task by simply considering Dirichlet eigenvalues of subgraphs of host graphs. I will derive tight bounds for the gap of one-dimensional, hypercube, and general convex subgraphs. The techniques used will also adapt methods recently used by Andrews and Clutterbuck to prove the long-standing ``Fundamental Gap Conjecture''.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The analysis of system calls is one method employed by anomaly detection systems to recognise malicious code execution. Similarities can be drawn between this process and the behaviour of certain cells belonging to the human immune system, and can be applied to construct an artificial immune system. A recently developed hypothesis in immunology, the Danger Theory, states that our immune system responds to the presence of intruders through sensing molecules belonging to those invaders, plus signals generated by the host indicating danger and damage. We propose the incorporation of this concept into a responsive intrusion detection system, where behavioural information of the system and running processes is combined with information regarding individual system calls.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The purpose of this research is to discover development points for business processes and sales reporting in the recovered paper sourcing organization. The processes under development are both sales and sourcing processes that were determined by the commissioning company. All of these processes have in common that there are used sales orders to organize the money flows correctly. Although the main objective is to source only recovered paper, the sourcing also brings by-products that cannot be utilized and are thus sold. As the purpose of the sales function is to only support the sourcing strategy, it should be organized as efficiently as possible. Investigating the current status of the processes and finding development points help in building proposals for enhanced process descriptions. In order that sales function could be analyzed, should the sales reporting be accurate and present the needed key figures. The current status of the processes as well as the possible problems and development ideas were researched with the help of interviews. Best practices could also be brought from other business lines in the commissioning company. The theory part was build according to relevant literature and scientific articles. The research indicates, that processes have shaped differently in sourcing organization’s business units. Local infrastructure and legislation sets certain limitations to the sourcing of recovered paper, and these circumstances cannot be changed. Customer-supplier power relations also affect to the formulation of business processes. In order to steer the processes, there has to be more internal controls. Still, the enterprise resource planning system also sets boundaries how the processes can be made more efficient.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Coarsening is a ubiquitous phenomenon [1-3] that underpins countless processes in nature, including epitaxial growth [1,3,4], the phase separation of alloys, polymers and binary fluids [2], the growth of bubbles in foams5, and pattern formation in biomembranes6. Here we show, in the first real-time experimental study of the evolution of an adsorbed colloidal nanoparticle array, that tapping-mode atomic force microscopy (TM-AFM) can drive the coarsening of Au nanoparticle assemblies on silicon surfaces. Although the growth exponent has a strong dependence on the initial sample morphology, our observations are largely consistent with modified Ostwald ripening processes [7-9]. To date, ripening processes have been exclusively considered to be thermally activated, but we show that nanoparticle assemblies can be mechanically coerced towards equilibrium, representing a new approach to directed coarsening. This strategy enables precise control over the evolution of micro- and nanostructures.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

We review our work on generalisations of the Becker-Doring model of cluster-formation as applied to nucleation theory, polymer growth kinetics, and the formation of upramolecular structures in colloidal chemistry. One valuable tool in analysing mathematical models of these systems has been the coarse-graining approximation which enables macroscopic models for observable quantities to be derived from microscopic ones. This permits assumptions about the detailed molecular mechanisms to be tested, and their influence on the large-scale kinetics of surfactant self-assembly to be elucidated. We also summarise our more recent results on Becker-Doring systems, notably demonstrating that cross-inhibition and autocatalysis can destabilise a uniform solution and lead to a competitive environment in which some species flourish at the expense of others, phenomena relevant in models of the origins of life.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In recent decades, it has been definitely established the existence of a close relationship between the emotional phenomena and rational processes, but we still do not have a unified definition, or effective models to describe any of them well. To advance our understanding of the mechanisms governing the behavior of living beings we must integrate multiple theories, experiments and models from both fields. In this paper we propose a new theoretical framework that allows integrating and understanding, from a functional point of view, the emotion-cognition duality. Our reasoning, based on evolutionary principles, add to the definition and understanding of emotion, justifying its origin, explaining its mission and dynamics, and linking it to higher cognitive processes, mainly with attention, cognition, decision-making and consciousness. According to our theory, emotions are the mechanism for brain function optimization, besides being the contingency and stimuli prioritization system. As a result of this approach, we have developed a dynamic systems-level model capable of providing plausible explanations for some psychological and behavioral phenomena, and establish a new framework for scientific definition of some fundamental psychological terms.