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Análise estrutural de galpões atirantados de concreto pré-moldado / Structural analysis of sheds with tied portal frames of precast concreteAndreilton de Paula Santos 08 June 2010 (has links)
Os galpões de concreto pré-moldado, formados por pórticos atirantados, são muito utilizados, no Brasil. Porém, para o projeto dessas estruturas, a bibliografia é limitada. Além disso, vários critérios de projeto são adaptados dos relativos a estruturas de concreto moldado no local e de múltiplos pavimentos. O objetivo deste trabalho é contribuir para a análise desse tipo de estrutura, introduzindo conceitos que dificilmente são considerados na prática, tais como: rigidez da ligação viga-pilar, análise não-linear física e geométrica, deformação excessiva e fluência. A pesquisa foi desenvolvida por meio de análises estruturais, usando modelos de galpões comuns na prática. Cada conceito citado anteriormente foi analisado em exemplos. A rigidez da ligação viga-pilar foi avaliada com base no parâmetro de restrição à rotação, \'alfa\'R. A não-linearidade física (NLF) do concreto foi considerada pelo método de Branson. Para a não-linearidade geométrica (NLG), foram utilizados os parâmetros \'alfa\' e o processo P.\'delta\'. A deformação excessiva, incluindo a fluência, foi discutida tendo em conta os aspectos normativos. Constatou-se que a ligação viga-pilar pode ter comportamento semi-rígido em alguns casos, mas, se corretamente dimensionada, apresenta, de fato, comportamento rígido. A consideração da NLF apresentou resultados melhores que a análise elástica linear, sendo possível, para o exemplo estudado, utilizar um coeficiente redutor de inércia igual a 0,5, para as vigas e para os pilares do pórtico. Concluiu-se, também, que a consideração da NLG deve ser feita sistematicamente para esse tipo de estrutura, uma vez que alguns exemplos apresentaram acréscimos de momentos superiores a 10% e \'alfa\' > \'alfa\' lim. Além disso, observou-se que a verificação do estado limite de deformação excessiva (ELS-DEF) pode ser determinante na escolha das seções transversais do pórtico, sendo obrigatória a consideração da fluência. Nesse sentido, o presente trabalho contribui para a literatura técnica sobre a análise estrutural dos galpões atirantados, auxiliando projetistas no cálculo dessas estruturas e servindo de referência nos cursos sobre esse assunto. / Sheds of precast concrete formed by tied portal frames are widely used in Brazil. However, there are few works on the design of these structures. In addition, several design criteria are adapted from those relative to the structures of cast in place concrete and multi-storey buildings. The objective of this work is to contribute to the analysis of this type of structure, introducing concepts that are hardly seen in practice, such as: rigidity of beam-column connection, physics and geometric nonlinear analysis, excessive deformation, and creep. The research was developed by mean of structural analysis, using models of sheds common in practice. Each concept previously mentioned was analyzed in examples. The stiffness of the beam-column connection was evaluated with base on the restriction parameter of the rotation, \'alfa\'R. The physics non-linearity (PNL) of concrete was considered by the method of Branson. For the geometric non-linearity (GNL) the parameter \'alfa\' and the process P.\'delta\' were used. The excessive deformation including creep was discussed taking in account the aspects of brazilian codes. It was found that the beam-column connection may have semi-rigid behavior in some cases, but, if properly designed, it has in fact rigid behavior. The consideration of the PNL had better results than the linear elastic analysis, and, for the sample studied, was possible to use a reduction coefficient of inertia equal to 0.5 for the beams and columns of the portal frame. It was also concluded that the consideration of GNL should be done systematically for this type of structure, since as some examples showed increase of moments above 10% and \'alfa\' > \'alfa\' lim. Furthermore, it was observed that the verification of deflection serviceability can be decisive in the choice of the portal frame cross sections, being obligatory the consideration of creep. In this sense, the present work contributes to the technical literature on the structural analysis of the tied portal frame sheds, helping engineers in the design of these structures and serving as reference in courses about this subject.
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Análise não-linear física simplificada de estruturas de contraventamento de edifícios de alvenaria estrutural / Simplified physical non-linear analysis on shear wall masonry buildingsDenise Itajahy Sasaki Gomes 19 May 2010 (has links)
Neste trabalho são discutidos os aspectos referentes à análise não-linear física de painéis de contraventamento em alvenaria estrutural. O objetivo foi a obtenção de coeficientes a serem aplicados ao produto de rigidez à flexão (EI) para a consideração da não-linearidade física de forma simplificada. As estruturas foram analisadas de forma paramétrica através de um modelo de elementos finitos lineares (pórtico plano), com a utilização de duas diferentes taxas de armaduras para uma combinação de ação horizontal e vertical aplicada. A ação horizontal limitou o deslocamento do topo do painel em H/3500, nas análises lineares. A ação vertical simulou a reação de uma laje com peso próprio e sobrecargas de utilização. A alvenaria foi considerada como um meio contínuo e homogêneo (macro-modelos). Foi apresentada uma metodologia para a obtenção do coeficiente de rigidez à flexão para ser aplicado nas análises lineares e simular o efeito da não-linearidade física. Os valores do coeficiente de redução do produto de rigidez à flexão apresentaram-se muito baixos, com uma variação de 0,1 a 0,4, sugerindo a verificação do modelo matemático bem como do programa utilizado nas análises. / This study deals with aspects related to the nonlinear analysis of physical shear walls in masonry. The objective was to obtain coefficients to be applied to the product of bendind stiffness (EI) for considering physically nonlinear behavior in a simplified analysis. The structures were analyzed usig a parametric finit element model using linear elements (plane frame), with two different reinforcement ratios for one combination of horizontal and vertical actions. The horizontal action limited de top displacement of the shear wall in H/3500. The vertical loads simulated the reaction of a slab with self-weight and burdens of use. The masonry was considered as a means continuous and homogeneous (Macro-models). Was presented a methodology for obtaining the coefficient of bending stiffness to be applied in linear analysis and simulate the effect of non-linearity. The coefficient of reduction product of bending stiffness were very low, with a variation of 0.1 to 0.4, suggesting the verification of mathematical model and the program used in the analysis.
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Framing the Water Challenge : Multilateral donor policies for water supply and sanitation 1960-2005Bohman, Anna January 2006 (has links)
Opinions on what is best way to provide more people in low income countries with adequate water and sanitation services have changed over time. A recent policy paradigm suggests that private companies should be involved in WSS service provision to improve the situation for those in need. This study looks at how issues of water supply and sanitation (WSS) have been confronted by the international donor community and how strategies to improve performance in this sector have changed from the early 1970’s up until today. The evolution of ideas and strategies are linked to overall development policies in order to better understand the forces that have shaped policy redirections in the sector. In addition, the case study of Ghana gives a preliminary picture of how donor policies have been played out in a national context. The concept of problem frames is used as an analytical tool in order to highlight how ideas change and replace each other but also to illustrate how problem frames are becoming more inclusive as new knowledge and experiences are gained. The study finds that while hardware knowledge such as engineering skills were put at the forefront to begin with, software matters such as capacity building and appropriate management of the sector gained increased attention with time. As the water challenge becomes increasingly framed as a matter of managing scarcity, the economic value of water is emphasized and private sector participation is promoted on a larger scale. With time the cross sectoral nature of the WSS issue gains increased attention as its overall impact on poverty reduction and environmental sustainability is emphasized. This holistic approach also contributes to an increased emphasis on sanitation as important to sustainable WSS systems and services. The case study of Ghana shows that all in all, institutional change within the Ghanaian WSS sector during the post independence era, mirror international policy trends. Power is moving out from the state in different directions and responsibilities are gradually hived off from the central organization to local authorities or other agencies working on specific issues. Subsidies on water tariffs are abolished and at the end of the period the private sector is also invited to act in the sector. However, recent trends indicate that as democracy deepens and civil society is growing stronger this also effects policy development in the Ghanaian WSS sector.
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Gay Marriage in the Utah and California Media: A Content Analysis of Newspaper Frames Used in the Coverage of Proposition 8Hollingshead, Michael Todd 05 July 2012 (has links)
This study is a content analysis of news frames used in the coverage of Proposition 8 by newspapers in Utah and California, spanning the three months prior to its passage in November 2008, to the three months after its passage. A total of 401 news stories from five newspapers were analyzed to examine which of five news frames (attribution of responsibility, human interest, conflict, morality, and economic consequence) were used most predominantly and if the use of those frames varied by newspaper. Conflict was the most predominantly used frame, followed by attribution of responsibility, morality, economic consequence and human interest. The use of news frames did vary by newspaper. The newspapers in Utah used the morality frame more often in their coverage of Proposition 8 than the newspapers in California. Framing choices by the newspapers also changed over time. The use of the human interest frame decreased sharply after the November ballot vote, while the use of the responsibility frame and conflict frame showed a meaningful increase.
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Framing Homelessness as Crisis: A Comparative Content Analysis of Local Media Reports on Portland's Tent CitiesCokeley, Katrien 29 September 2017 (has links)
This content analysis of mainstream and alternative news narratives interprets the use of the crisis media frame, and describes the relationship between local policy initiatives, media discourse and public opinion on tent cities, organized by people experiencing homelessness in Portland, Oregon. Framing homelessness and housing as a crisis intensified the public debate, attested by an increase in mainstream media reports on tent cities, and by controversial policy changes that addressed the individually-experienced traumatic impacts of the City's anti-camping ordinance, as well as the systemic lack of affordable housing and emergency shelter. Media discourse related to city-sanctioned tent cities blurs the lines between Shanto Iyengar's episodic and thematic media frames because of the simultaneous acknowledgement of individual and systemic circumstances. The crisis frame is a discursive mechanism in the production of knowledge on homelessness and housing, and is considered as an integral characteristic of Henri Lefebvre's conceptual model of socio-spatial production, which describes the interdependency between discourse, practice and meaning in the material and symbolic production of space.
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Part-of-Speech Bootstrapping Using Lexically-Specific FramesLeibbrandt, Richard Eduard, richard.leibbrandt@flinders.edu.au January 2009 (has links)
The work in this thesis presents and evaluates a number of strategies by which English-learning children might discover the major open-class parts-of-speech in English (nouns, verbs and adjectives) on the basis of purely distributional information. Previous work has shown that parts-of-speech can be readily induced from the distributional patterns in which words occur. The research reported in this thesis extends and improves on this previous work in two major ways, related to the constructional status of the utterance contexts used for distributional analysis, and to the way in which previous studies have dealt with categorial ambiguity.
Previous studies that have induced parts-of-speech from word distributions have done so on the basis of fixed windows of words that occur before and after the word in focus. These contexts are often not constructions of the language in question, and hence have dubious status as elements of linguistic knowledge. A great deal of recent evidence (e.g. Lieven, Pine & Baldwin, 1997; Tomasello, 1992) has suggested that childrens early language may be organized around a number of lexically-specific constructional frames with slots, such as a X, you X it, draw X on X. The work presented here investigates the possibility that constructions such as these may be a more appropriate domain for the distributional induction of parts-of-speech. This would open up the possibility of a treatment of part-of-speech induction that is more closely integrated with the acquisition of syntax.
Three strategies to discover lexically-specific frames in the speech input to children are presented. Two of these strategies are based on the interplay between more and less frequent words in English utterances: the more frequent words, which are typically function words or light verbs, are taken to provide the schematic backbone of an utterance. The third strategy is based around pairs of words in which the occurrence of one word is highly predictable from that of the other, but not vice versa; from these basic slot-filler relationships, larger frames are assembled.
These techniques were implemented computationally and applied to a corpus of child-directed speech. Each technique yielded a large set of lexically-specific frames, many of which could plausibly be regarded as constructions. In a comparison with a manual analysis of the same corpus by Cameron-Faulkner, Lieven and Tomasello (2003), it is shown that most of the constructional frames identified in the manual analysis were also produced by the automatic techniques.
After the identification of potential constructional frames, parts-of-speech were formed from the patterns of co-occurrence of words in particular constructions, by means of hierarchical clustering. The resulting clusters produced are shown to be quite similar to the major English parts-of-speech of nouns, verbs and adjectives. Each individual word token was assigned a part-of-speech on the basis of its constructional context. This categorization was evaluated empirically against the part-of-speech assigned to the word in question in the original corpus. The resulting categorization is shown to be, to a great extent, in agreement with the manual categorization.
These strategies deal with the categorial ambiguity of words, by allowing the frame context to determine part-of-speech. However, many of the frames produced were themselves ambiguous cues to part-of-speech. For this reason, strategies are presented to deal with both word and context ambiguity. Three such strategies are proposed. One considers membership of a part-of-speech to be a matter of degree for both word and contextual frame. A second strategy attempts to discretely assign multiple parts-of-speech to words and constructions in a way that imposes internal consistency in the corpus. The third strategy attempts to assign only the minimally-required multiple categories to words and constructions so as to provide a parsimonious description of the data.
Each of these techniques was implemented and applied to each of the three frame discovery techniques, thereby providing category information about both the frame and the word. The subsequent assignment of parts-of-speech was done by combining word and frame information, and is shown to be far more accurate than the categorization based on frames alone. This approach can be regarded as addressing certain objections against the distributional method that have been raised by Pinker (1979, 1984, 1987).
Lastly, a framework for extending this research is outlined that allows semantic information to be incorporated into the process of category induction.
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IVIK elevers skolintroduktion : Studie-och yrkesvägledares roll i skolintroduktionen för nyanlända invandrarungdomar i gymnasieåldern.Bernedal, Emili, Lehikoinen, Paula January 2007 (has links)
<p>Syftet med uppsatsen var att undersöka studie- och yrkesvägledarens roll i skolintroduktionen för nyanlända invandrarungdomar i gymnasieåldern. Studie- och yrkesvägledare har intervjuats i fem kommuner i Stockholms län. Utifrån ett kvalitativt tillvägagångssätt vill vi undersöka studie- och yrkesväledarens roll i skolverksamheten och dess ramar. Resultatet visar att studie- yrkesvägledarna upplevde att samverkan och tidsaspekten var begränsande faktorer i introduktionsarbetet. Det framkom även hur de yttre och inre ramar påverkar kommuner och skolverksamheter, vilka ses som hinder. Uppsatsen tydliggör vikten av att en nationell strategi för skolintroduktion för nyanlända invandrarungdomar behövs.</p><p>The purpose of this study is to elucidate the role of guidance counsellor for newly arrived immigrants of 16 - 20 years of age. The study has been taking place in five municipalities in Stockholm County, where counsellors have been interviewed. A qualitative attempt has been used to illuminate the counsellors role in school activity and there frames. The result shows that the counsellors experienced co- operation and time aspect as limitation factors in the work with school introduction. The result also told that the internal and external frames influence the local goverment and school activity in a limitation form. The study expresses the impotance of a national strategy for school introduction of newly arrived immigrants.</p>
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Image coding with H.264 I-frames / Stillbildskodning med H.264 I-framesEklund, Anders January 2007 (has links)
<p>In this thesis work a part of the video coding standard H.264 has been implemented. The part of the video coder that is used to code the I-frames has been implemented to see how well suited it is for regular image coding. The big difference versus other image coding standards, such as JPEG and JPEG2000, is that this video coder uses both a predictor and a transform to compress the I-frames, while JPEG and JPEG2000 only use a transform. Since the prediction error is sent instead of the actual pixel values, a lot of the values are zero or close to zero before the transformation and quantization. The method is much like a video encoder but the difference is that blocks of an image are predicted instead of frames in a video sequence.</p> / <p>I det här examensarbetet har en del av videokodningsstandarden H.264 implementerats. Den del av videokodaren som används för att koda s.k. I-bilder har implementerats för att testa hur bra den fungerar för ren stillbildskodning. Den stora skillnaden mot andra stillbildskodningsmetoder, såsom JPEG och JPEG2000, är att denna videokodaren använder både en prediktor och en transform för att komprimera stillbilderna, till skillnad från JPEG och JPEG2000 som bara använder en transform. Eftersom prediktionsfelen skickas istället för själva pixelvärdena så är många värden lika med noll eller nära noll redan innan transformationen och kvantiseringen. Metoden liknar alltså till mycket en ren videokodare, med skillnaden att man predikterar block i en bild istället för bilder i en videosekvens.</p>
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Intern kommunikation och meningsskapande vid en strategisk organisationsförändring : en studie av Sveriges TelevisonPlaten, Sara von January 2006 (has links)
<p>Abstract</p><p>Planned change and change-related communication are perceived very differently by the members of an organization. Strongly varying perceptions of new tasks, work processes and goals make joint action difficult and cause the failure of many change initiatives. The purpose of this study is to investigate how internal communication and sensemaking processes contribute to the perception of strategic change among the members of a public service organization. The following questions are answered: How does the management plan and perform internal communication during a strategic change of the Swedish public service television company Sveriges Television (SVT)? How do the members of the organization make sense of a strategic change and the internal communication related to the changes that are planned and carried out?</p><p>A social constructivist perspective combined with theories of sensemaking, communication, social identities, roles, groups, power and status constitutes the analytical framework. The investigation is designed as two case studies of the SVT production facilities in Malmö and Örebro. The empirical material consists mainly of personal interviews. Written documents and observations have also been used. The case studies took place between 2002 and 2004. Some main conclusions are as follows:</p><p>1) Internal communication is central for how members of an organization make sense of, and participate in, major change. Yet, not even in ideal communication situations do the employees experience that the information has been sufficient and that they have been included in the change process. There are thus reasons for more balanced expectations of what is possible to achieve with internal communication during strategic change. 2) The most influential factor determining how people make sense of change-related communication is the practical everyday reality that constitutes their frames of reference. The reluctance to consider, and act upon, how other individuals conceive of a situation leads to misdirected internal communication and gaps of understanding. 3) Organizational identities, group membership, roles and status function as frames of reference when employees make sense of changes. But irrespective of whether the changes take place on an organizational, departmental or group level, personal identities are the most influential frames of reference for interpreting organizational change. The investigation thus establishes an order of precedence for frames of reference that has important implications for internal communication during strategic change.</p><p>The thesis contributes to sensemaking theories by demonstrating their extensive ability to explain mutually related phenomena, such as attention, resistance and self-fulfilling prophecies. The apparent ability to explain basically all sensemaking-related issues in organizations, and thus leading to reductionism, is also concluded to be one of the weaknesses of the theories. By connecting sensemaking theories with roles, social identities and power, the study contributes to clarifying the frame concept.</p><p>Key words: internal communication, sensemaking, strategic change, public service, Sveriges Television, frames of reference, organizational identity, roles, status.</p><p>Kontakt: saradalfelt@yahoo.se</p>
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Framing the Water Challenge : Multilateral donor policies for water supply and sanitation 1960-2005Bohman, Anna January 2006 (has links)
<p>Opinions on what is best way to provide more people in low income countries with adequate water and sanitation services have changed over time. A recent policy paradigm suggests that private companies should be involved in WSS service provision to improve the situation for those in need.</p><p>This study looks at how issues of water supply and sanitation (WSS) have been confronted by the international donor community and how strategies to improve performance in this sector have changed from the early 1970’s up until today. The evolution of ideas and strategies are linked to overall development policies in order to better understand the forces that have shaped policy redirections in the sector. In addition, the case study of Ghana gives a preliminary picture of how donor policies have been played out in a national context. The concept of problem frames is used as an analytical tool in order to highlight how ideas change and replace each other but also to illustrate how problem frames are becoming more inclusive as new knowledge and experiences are gained.</p><p>The study finds that while hardware knowledge such as engineering skills were put at the forefront to begin with, software matters such as capacity building and appropriate management of the sector gained increased attention with time. As the water challenge becomes increasingly framed as a matter of managing scarcity, the economic value of water is emphasized and private sector participation is promoted on a larger scale. With time the cross sectoral nature of the WSS issue gains increased attention as its overall impact on poverty reduction and environmental sustainability is emphasized. This holistic approach also contributes to an increased emphasis on sanitation as important to sustainable WSS systems and services.</p><p>The case study of Ghana shows that all in all, institutional change within the Ghanaian WSS sector during the post independence era, mirror international policy trends. Power is moving out from the state in different directions and responsibilities are gradually hived off from the central organization to local authorities or other agencies working on specific issues. Subsidies on water tariffs are abolished and at the end of the period the private sector is also invited to act in the sector. However, recent trends indicate that as democracy deepens and civil society is growing stronger this also effects policy development in the Ghanaian WSS sector.</p>
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