884 resultados para Theories and Models


Relevância:

90.00% 90.00%

Publicador:

Resumo:

When designing systems that are complex, dynamic and stochastic in nature, simulation is generally recognised as one of the best design support technologies, and a valuable aid in the strategic and tactical decision making process. A simulation model consists of a set of rules that define how a system changes over time, given its current state. Unlike analytical models, a simulation model is not solved but is run and the changes of system states can be observed at any point in time. This provides an insight into system dynamics rather than just predicting the output of a system based on specific inputs. Simulation is not a decision making tool but a decision support tool, allowing better informed decisions to be made. Due to the complexity of the real world, a simulation model can only be an approximation of the target system. The essence of the art of simulation modelling is abstraction and simplification. Only those characteristics that are important for the study and analysis of the target system should be included in the simulation model. The purpose of simulation is either to better understand the operation of a target system, or to make predictions about a target system’s performance. It can be viewed as an artificial white-room which allows one to gain insight but also to test new theories and practices without disrupting the daily routine of the focal organisation. What you can expect to gain from a simulation study is very well summarised by FIRMA (2000). His idea is that if the theory that has been framed about the target system holds, and if this theory has been adequately translated into a computer model this would allow you to answer some of the following questions: · Which kind of behaviour can be expected under arbitrarily given parameter combinations and initial conditions? · Which kind of behaviour will a given target system display in the future? · Which state will the target system reach in the future? The required accuracy of the simulation model very much depends on the type of question one is trying to answer. In order to be able to respond to the first question the simulation model needs to be an explanatory model. This requires less data accuracy. In comparison, the simulation model required to answer the latter two questions has to be predictive in nature and therefore needs highly accurate input data to achieve credible outputs. These predictions involve showing trends, rather than giving precise and absolute predictions of the target system performance. The numerical results of a simulation experiment on their own are most often not very useful and need to be rigorously analysed with statistical methods. These results then need to be considered in the context of the real system and interpreted in a qualitative way to make meaningful recommendations or compile best practice guidelines. One needs a good working knowledge about the behaviour of the real system to be able to fully exploit the understanding gained from simulation experiments. The goal of this chapter is to brace the newcomer to the topic of what we think is a valuable asset to the toolset of analysts and decision makers. We will give you a summary of information we have gathered from the literature and of the experiences that we have made first hand during the last five years, whilst obtaining a better understanding of this exciting technology. We hope that this will help you to avoid some pitfalls that we have unwittingly encountered. Section 2 is an introduction to the different types of simulation used in Operational Research and Management Science with a clear focus on agent-based simulation. In Section 3 we outline the theoretical background of multi-agent systems and their elements to prepare you for Section 4 where we discuss how to develop a multi-agent simulation model. Section 5 outlines a simple example of a multi-agent system. Section 6 provides a collection of resources for further studies and finally in Section 7 we will conclude the chapter with a short summary.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

O presente trabalho, no âmbito de projeto final de curso de metrado em Engenharia da Construção, teve como objetivo o estudo do comportamento de estruturas de suporte de terras flexíveis multi-apoiadas (com diferentes tipos de apoio) para dois tipos solos homogéneos. Recorreu-se às teorias clássicas, como a de Rankine, desenvolvidas para estruturas de suporte de terras rígidas. Às teorias semi-empíricas de Terzaghi & Peck que culminaram nos diagramas de Terzaghi & Peck. Apesar de os digramas de Terzaghi & Peck serem diagramas de pressões de terras a usar em estruturas de suporte de terras flexíveis, apresentam algumas limitações importantes, como a sua aplicação apenas em solos heterogéneos, com presença ou não de níveis freáticos, e sem fornecer distribuição das pressões de terras na zona passiva (zona enterrada). Como na atualidade os modelos de elementos finitos permitem simular de modo muito mais rigoroso os problemas da engenharia. O presente trabalho esteve focado em analisar um caso prático em diferentes solos e com diferentes tipos de apoios. Será estudado mediante os métodos analíticos usando as teorias clássicas e posteriormente métodos numéricos (com diferentes programas de cálculo). Finalmente serão comparados os resultados obtidos mediante os diferentes métodos usados. As estruturas foram inicialmente pré-dimensionadas usando os métodos clássicos. Assim foram usados os diagramas de pressões de terras de Terzaghi & Peck para a zona ativa (zona em escavação) e a teoria de Rankine para conhecer as pressões de terras na zona enterrada da cortina (parede moldada) e recorrendo ao software Ftool para a obtenção dos parâmetros de dimensionamento de estruturas de suporte de terras objeto de estudo. Posteriormente utilizaram-se os programas de cálculo automático CYPE 2015 k, e o programa de cálculo de elementos finitos PLAXIS Introductory 2010. Estes programas permitem simular o faseamento construtivo do muro. Para estudar a influência de algúns parâmetros no comportamento da Resumo IV cortina o estudo foi realizado com dois solos distintos, um solo argiloso mole e um solo arenoso denso. Assim como para dois tipos de apoios distintos, ancoragens ativas e escoras passivas. Foram analisados diferentes parâmetros na estrutura de suporte; pressões horizontais das terras, deslocamentos horizontais, esforço axial, transverso e momento fletor.

Relevância:

90.00% 90.00%

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.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Black students are consistently overrepresented in categories of academic underachievement. Parent engagement has long been touted as an effective strategy for improving the educational outcomes of Black children. However, most parent engagement research reflects deficit based perspectives frame Black parents as problems that must be fixed or mitigated before they can positively contribute to their children’s education. Consequently, parent engagement research and frameworks ignore the perspectives of Black parents and the assets they use to participate effectively in parent engagement. In this case study, I draw on individual and focus group interview data, documents, and observations, to examine how fifteen Black families, collectively known as FACE: 1) define and participate in parental engagement, 2) experience barriers to and opportunities for engagement, and 3) experience benefits of engagement for their children and their own personal development. Guided by Black Feminist and Critical Race Theories, I show how Black families in this study used a myriad of engagement strategies to improve their children’s educational experiences which were invisible to schools and how they used school-sanctioned engagement activities to meet their own objectives. Ultimately, I argue that school-centered parent engagement frameworks and models are ineffective for empowering Black families and accounting for the essential ways that these families contribute to the well-being of their children. Based on my findings, I discuss implications for theory, practice and policy, and research, and make recommendations for a more family-centered approach to parent engagement.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This project proposes a feminist intervention in how affect and publics are theorized in public relations research. Drawing from extant literature, I argue that public relations theories of affect and publics have been apolitical and lack depth and context (Leitch & Motion, 2010a). Using the context of the online childhood vaccine debate, I illustrate several theories and concepts of the new feminist affective turn, as well as postmodern theories of affect, relevant to public relations research: (a) Public Feelings, “ugly” feelings, agency, and community (Cvetkovich, 2012; Ngai, 2007); (b) passionate politics (Mouffe, 2014); (c) postmodern assemblages, biopower, and body politics (Deleuze & Guattari, 1988; Foucault, 1984); (d) affective facts and logics of future threats (Massumi, 2010); and (e) affective ethics (Bertleson & Murphie, 2010). Scholarship in the areas of public relations, risk, feminist and postmodern affect theory, and the vaccine debate provided theoretical grounding for this project. My research questions asked: How is feminist affect theory embodied by mothers in the vaccine debate? How do mothers understand risks as affective facts in the vaccine debate (if at all)? What affective logics are used by mothers in the vaccine debate (if any)? And, What are sources of knowledge for mothers in the vaccine debate? Multi-sited online ethnographic methods were used to explore how feminist affect theory contributes to public relations research, including 29 one-on-one in-depth interviews with mothers of young children and participant observation of 15 online discussions about vaccines on parenting websites BabyCenter.com, TheBump.com, and WhatToExpect.com. I used snowball sampling to recruit interview participants and grounded theory (Glaser & Strauss, 1967) to analyze interview and online data. Results show that feminist affect theory contributes to theoretical and practical knowledge in public relations by politicizing and contextualizing understandings of publics and elucidating how affective facts and logics inform publics’ knowledge and choices, specifically in the context of risk. I also found evidence of suppression of dissent (Martin, 2015) and academic bias in vaccine debate research, which resulted in cultures of silence. Further areas of study included how specific contexts such as motherhood and issues of privilege and access affect publics’ experiences, knowledges, and choices.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Climate change communication has become a salient topic in science and society. It has grown to be something like a booming industry alongside more established ‘communication enterprises’, such as health communication, risk communication, and science communication. This article situates the theory of climate change communication within theoretical developments in the field of science communication. It discusses the importance and difficulties inherent in talking about climate change to different types of publics using various types of communication tools and strategies. It engages with the difficult issue of the relationship between climate change communication and behavior change, and it focuses, in particular, on the role of language (metaphors, words, strategies, frames, and narratives) in conveying climate change issues to stakeholders. In the process, it attempts to provide an overview of emerging theories of climate change communication, theories that recently have begun to proliferate quite dramatically. In some cases, we can, therefore only provide signposts to the most relevant research that is being carried out with regard to climate change communication without being able to engage with all its aspects. We end with an assessment of how communication could be improved in light of the theories and practices discussed in this article.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The main focus of the thesis concentrates on nationalism and how it is expressed through national myth and a hero. As a case study for Lithuania the cult of Vytautas the Great is used. Theses present how the myth of Vytautas the Great was created and why particularly the Grand duke became a national symbol. It also examines how main nationalism theories are reflected in this case. The main purpose of the thesis is to find out how this myth matches the needs of the current Lithuanian society – the last year schoolchildren (eighteen – nineteen years old) in particular. The main method used in the empirical part of the thesis is qualitative analysis: primary source material was gathered by using semi – structured interviews and the results were analyzed by employing thematic analysis. The theoretical part of the study presents the core nationalism and ethnic identity theories and describes the concepts of national myth and hero as well as their connection and influence for the society and Lithuanians precisely. In this study nationalism is understood as a phenomenon that holds a nation together and is reflected via certain national symbols such as national myths and heroes by forming a national identity the meaning of which is different for each generation. The analysis of the results in this study has showed that the idea of Vytautas the Great as a national hero – symbol, created in the interwar Lithuanian society has lost its significance for the current schoolchildren and has been replaced by other images. However, at the same time the Grand duke is still perceived as an embodiment of the main national Lithuanian virtues.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This paper addresses how, since the 1960s to the present, part of women's video art has broken the traditional representation of women’s body and proposed new forms of recording women's images, explicit or symbolic, using body part close-ups, and not sparing any efforts to ensure the prevention of the cataloguing of women’s bodies according to normative categories, such as gender, race and age, and in this way challenging the Western representation codes that objectify women. The methodology employed had as its primary purpose the examination of the association existing between the micro-sociological level of body gestures and performances in women's videos and the macro-sociological level of social forces such as the dimensions of gender and sexuality. This study concluded that narratives of identity and self-determination are present in women's video pieces contributing to women's empowerment through visual discourses that could possibly point to the production of new signs and symbols, new values and models, but also for the formation of new types of social roles and even a new type of interpersonal relationships.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Immigration disrupts an individual’s support network; however, the stresses of the immigration process increase the need for social support. The presence of social support becomes essential for immigrant children and adolescents to cope with these important transitional circumstances. Friends are both sources of social support and models for behavior. Furthermore, friendship networks are known to have a significant influence on youths’ functioning. Literature suggests that peer relations become more important in adolescence and friend support is related to child and adolescent well-being. Thus, friend relationships may be particularly important for immigrant youths who experience disruption in their friendship networks during the process of migration to another country. In addition to friendship networks and support, friend characteristics also need to be taken into consideration as important factors for immigrant youth adjustment. My study involved analyses of the effects of friend support and friend problem behaviors on emotional and behavioral functioning for elementary, middle, and high school age newly immigrant children and adolescents. Immigrant children and adolescents (N = 503) were interviewed at schools by interviewers fluent in participants’ languages. Structural Equation Modeling (SEM) analyses revealed that friend support and friend problem behaviors were related to children’s self-esteem and externalizing behaviors. In addition, friend problem behavior alone predicted children’s psychological symptoms and depression scores. Furthermore, age/grade was found to be a moderator for the relation between friend problem behavior and immigrant youth behavioral adjustment such that compared to elementary and high school cohorts, middle school youths showed more externalizing behaviors when they had friends performing problem behaviors. Results supported the idea that both friend support and friend behavior are related to newly immigrant youths’ emotional and behavioral adjustment. This study informs further research and interventions concerning the development of programs to facilitate immigrant youths’ adjustment by revealing friendship factors related to their adaptation.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Rapport de stage présenté à la Faculté des Arts et Sciences en vue de l’obtention du grade de Maître des Sciences (M. Sc.) en Criminologie, Option Stage en Intervention

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção do grau de Mestre em Psicologia especialidade em Psicologia da Saúde.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2016-10-03 07:59:09.638

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Semantic relations are an important element in the construction of ontology-based linguistic resources and models of problem domains. Nevertheless, they remain under-specified. This is a pervasive problem in both Software Engineering and Artificial Intelligence. Thus, we find semantic links that can have multiple interpretations, abstractions that are not enough to represent the relation richness of problem domains, and even poorly structured taxonomies. However, if provided with precise semantics, some of these problems can be avoided, and meaningful operations can be performed on them that can be an aid in the ontology construction process. In this paper we present some insightful issues about the representation of relations. Moreover, the initiatives aiming to provide relations with clear semantics are explained and the inclusion of their core ideas as part of a methodology for the development of ontology-based linguistic resources is proposed.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Semantic relations are an important element in the construction of ontologies and models of problem domains. Nevertheless, they remain fuzzy or under-specified. This is a pervasive problem in software engineering and artificial intelligence. Thus, we find semantic links that can have multiple interpretations in wide-coverage ontologies, semantic data models with abstractions that are not enough to capture the relation richness of problem domains, and improperly structured taxonomies. However, if relations are provided with precise semantics, some of these problems can be avoided, and meaningful operations can be performed on them. In this paper we present some insightful issues about the modeling, representation and usage of relations including the available taxonomy structuring methodologies as well as the initiatives aiming to provide relations with precise semantics. Moreover, we explain and propose the control of relations as a key issue for the coherent construction of ontologies.