A Displacement Based Optimization (DBO) approach was applied to truss design problems with material nonlinearities, to explore feasibility and verify efficiency of the approach to solve such problem. Various truss sizing problems with holonomic (path-independent) elastoplastic laws were investigated. This type of material nonlinearity allows us to naturally extend the linear elastic truss sizing in the DBO setting to nonlinear problems. A computer program that uses the commercially available optimizer DOT by VR&D and IMSL Linear Programming solver by Visual Numerics was developed to solve this type of problems. For comparison, we chose an important class of minimum-weight truss design problems, where holonomic linear strain hardening behavior was used. Additional examples of optimum design of trusses with elastic perfectly plastic material response that could be easily solved by Limit Design approach using linear programming were investigated for comparison. All demonstrated examples were tested successfully using the DBO approach. Solutions of comparable examples were consistent with the available results by other methods. Computational effort associated with the DBO approach was minimal for all the examples studied. Optimum solutions of several examples proved that the DBO approach is particularly suited for truss topology design where removal of truss members is essential. / Master of Science

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24171号 / 理博第4862号 / 新制||理||1695(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 西村 卓也, 教授 宮﨑 真一, 准教授 深畑 幸俊 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

A non-linear finite element program to simulate the behaviour of infilled frames and plane stress reinforced concrete members under the action of monotonic and cyclic loading has been developed. Steel is modelled as a strain hardening plastic material, and in the concrete model cracking, yielding and crushing are considered. The separation, sliding, and opening and closing of initial gaps at the interfaces between the frame and the infill panels are accounted for by adjusting the properties of interface elements. The non-linear equations of equilibrium are solved using an incremental-iterative technique performed under load or displacement control. The iterative techniques use the standard and modified Newton-Raphson method or the secant Newton method. An automatic load incrementation scheme, line searches, and restart facilities are included. The capabilities of the program have been examined and demonstrated by analysing five reinforced concrete panels, a deep beam, a shear wall, and eight infilled frames. The accuracy of the analytical results was assessed by comparing them with the experimental results and those obtained analytically by other workers and shown to be good. A study of the effects of some material and numerical parameters on the results of analyses of reinforced concrete deep beam has been carried out. Two techniques have been proposed and used to overcome numerical problems associated with local strain concentrations which occur with the displacement control, when path dependent incremental iterative procedures are used for inelastic materials. The displacement control provided with these modifications has been shown to be more efficient than the load control. / Iraqi Government

This dissertation examines the political negotlations involved in border encounters, focusing particularly on mobile groups in border areas in South America. It discusses the connection between international and border politics, privileging a definition of the latter as the negotiation processes over the terms and modes of presence of the 'inter' of the international. The dissertation analyzes border politics from the perspective of three major tenets: displacement, practices of zoning and the construction of borders as sites of solidarity. I argue that in order to understand these processes we need to elucidate how the global politics of mobility is played out (or translated) in border crossroads and from a range of social groups that encompass not only the Nation-State, but also a myriad of actors that, despite having little or no say in the international framework of human mobility, perform bordering practices that are central to the enactment of difference as a primary trait of inclusion/exclusion from the political. These processes of political differentiation are reinforced but also contested by mobile groups, especially in relation to discourses that try to equate human mobility as a choice between freedom and protection. In important respects, their intervention attempts to problematize the dichotomous portrayal of freedom and protection as two irreconcilable dimensions of life in displacement, thus evincing the possibility that the 'inter' of the international can actually become a site of living, rather than a rite of passage. I also argue that by incorporating the narratives of diverse social actors at these border crossroads we might come closer to displacing the politics of human mobility from one premised on a conventional reading of the international, as a strategy of separation, modulation and management of difference, towards a global politics of (dis)connections, in which mobile groups can become active participants in the framing of their lives possibilities. This moving-away from the international is always embedded in tenuous, dangerous and ambiguous exchanges about what constitutes mobility, how movement is to be interpreted, stimulated or prevented, where and when it can take place and under what conditions. The dissertation discusses these more theoretical claims in the context of refugee and migration movements in Brazil, particularly in relation to Bolivians, Africans and Colombians living in border zones. As such, this dissertation hopes to contribute to a better understanding of what is at stake in dealing with the border encounter from a political perspective and how different narratives on life in displacement can, in fact, indicate different paths of action and research, especially in the context of South-South circulations. / Thesis / Doctor of Philosophy (PhD)

This dissertation is relevant to structural engineers focusing on seismic design of structures using reinforced masonry. Specifically the thesis focuses on the seismic performance of reinforced masonry shear walls as seismic force resisting systems. / Reinforced masonry (RM) has been gaining a wide acceptance in the low- and mid-rise construction market as an economic and durable structural system. However, challenges still exist in the area of seismic design because of the poor performance of unreinforced masonry during recent earthquake events in Iran 2003, Haiti 2010, Japan 2011, New Zealand 2011 and Nepal 2015. The dissertation investigated the seismic performance of six concrete block structural walls in an effort to evaluate their force-, displacement- and performance- based seismic design parameters. The walls fall under the ductile shear wall/special reinforced wall seismic force resisting system (SFRS) classification according to the current North American masonry design standards. More specifically, the dissertation is focused on evaluating if such walls, designed under the same prescriptive design provisions, having different cross-section configurations would possess similar seismic performance parameters. This was established through an experimental and analytical program by subjecting the walls to a displacement controlled quasi-static cyclic analysis. Different wall configurations were tested including, rectangular, flanged and slab-coupled walls. Test results confirmed that walls designed under the same SFRS classification, but with different configurations, have different seismic performance parameters that included ductility capacity; yield and post yield displacement; stiffness degradation; period elongation and equivalent viscous damping. The current North American masonry design provisions do not account for such difference in the ductility capacities between the walls. The thesis analyses were concluded by quantifying the seismic vulnerability of a RM SFRS comprised of shear walls similar to those tested, through the development of collapse fragility curves and the assignment of an adjusted collapse margin ratio, ACMR following the FEMA P-58 and P-695 guidelines. The system were deemed acceptable since the ACMR was greater than ACMR10% (2.35 > 2.31). Therefore, the selected RM SFRS which was designed to meet the prescriptive requirements of the ductile masonry walls classification of the CSA S304 (CSA 2014), shows potential capacity against collapse under high intensity earthquakes in one of the highest seismic zones in western Canada and it should be considered as a viable SFRS to be used in seismic design. The procedure described in the chapter can be adopted to investigate the collapse fragility of other SFRS in different seismic regions through careful selection and scaling of the ground motion records associated with such region's seismicity. / Dissertation / Doctor of Philosophy (PhD)

As the consequences of climate change is increasing the need of replacing fossil fuels with renewable energy globally is becoming more urgent. A central question that has been questioned in the literature is that if the world is on track on a transition away from fossil fuels or if we are only adding renewable energy to the energy mix in a world that continues to grow and consume more energy. Because of the above mentioned, this thesis aims to investigate if the increased generation of electricity from renewable sources are displacing the generation of electricity from fossil fuels. This is tested using a time and country fixed effects model including 176 countries with yearly observations from 2000 to 2020. The result from the regression showed that one additional kWh electricity generated from renewable sources has not statistically managed to displace one kWh of electricity generated from fossil fuels, net of controls. Previous studies using a similar methodology but on older time frames has shown result were almost no displacement has occurred when renewable sources have been added. The result from this thesis should not be interpreted as that the transition is not going to happen since it might be that the global initiatives taken around the globe to make the transition happenis not get visible in the numbers used in thesis, but the result does on the other hand indicate that several economic, political, and social factors has made the transition to renewables difficult, and that we should not assume that renewable energy will replace fossil fuels for electricity generation without policy measures that supports the transition.

There is a grave concern for the life, liberty and security of individuals who have been forced to leave their homes and have become dispersed within their native countries and throughout the Asian continent. These internally displaced persons and refugees are the subject of this study. Some of the themes that will be discussed include: civil war, human rights violations and the economy, since these are the problems affecting the populations of Afghanistan, Pakistan and Myanmar. These case studies are of particular interest because Afghanistan is where most refugees come from, Myanmar has the longest-running military regime and Pakistan hosts the most refugees in the world. All three case studies are currently in a state of civil war, are breeding grounds for violations of human rights and have corrupt economies. Thus, the goal is to end armed conflict, to put an end to the human rights violations that come with it and to restructure the economies in each of these nation states so that the internally displaced persons and refugees can be repatriated, since displacement has become too much of a burden for Afghanistan, Pakistan and Myanmar's neighboring countries, who have been taking in all of the refugees from said countries. Theoretically, if the issues causing displacement were to be solved, then the countries that host refugees would be able to concentrate on their own populations. This study can potentially address the gap between knowledge, policy formation, and policy implementation to realize the goals of the international community in dealing with the displacement crisis.

The Indian government’s twin objectives of protecting the tiger population in the Nallamala forest in Andhra Pradesh and providing “development” to the indigenous Chenchu people have resulted in an on-going process of Chenchu displacement from the forest. The research is an anthropological intervention to comparatively analyze the development definitions of the Chenchu people (N=15), subgrouped location-wise as Deep Forest Chenchu, Intermediate Forest Chenchu, and Displaced Chenchu, and the Government and NGO representatives (N=13), including Integrated Tribal Development Agency representatives, NGO workers, and conservation authorities. Both groups defined development as access to basic amenities, education and jobs, health, freedom, livestock, and well-being in varying agreements. The study concludes that discrepancies exist in the development perspectives of the two groups, the Chenchu displacement is unsystematic, and the implementation of development projects was non-uniform. Small sample size, limited research time, and gender imbalance are some of the limitations of this study.

Competition has long been recognized as a central force in shaping evolution, particularly through character displacement. Yet research on character displacement is biased as it has focused almost exclusively on pairs of interacting species while ignoring multispecies interactions. Unfortunately, communities are seldom so simple that only pairs of species interact, and it is not clear if inferences from pairwise interactions are sufficient to explain patterns in nature. A more realistic approach is to ask how traits evolve when multiple species interact. Here I explore the importance of multispecies competitive interactions on trait evolution in four congeneric species of livebearing fishes in the genus Poeciliopsis (P. prolifica, P. viriosa, P. latidens, and P. presidionis). These species are found co-occurring throughout northwestern Mexico: My first chapter builds a framework for multispecies character displacement research by hypothesizing three effects that an unconsidered competitor, termed a hidden competitor, can have on pairwise interactions and the resulting pattern of character displacement. I show through these effects that research focused solely on pairwise interactions can be misleading for character displacement. I also provide suggestions on how to address character displacement research that incorporates more complexity. In chapter two, I test for character displacement in body shape in the four congeneric species. I found evidence for convergent character displacement in populations of P. prolifica, P. viriosa, and P. latidens. I also found that the convergence in body shape was not consistently in the same direction, meaning that when more than two species co-occurred I did not find a more extreme body shape that when only two species co-occurred. On the contrary, body shape when more than two competitors co-occurred seemed to be intermediate between the shape of two competitors and no competitor. This intermediate shape suggests that evolution in multispecies communities may occur in response to several competitors, rather than pairwise interactions. Finally, in chapter three, I test the effect of several hypothetical selective pressures on life history of P. prolifica, including intraspecies and interspecies competition, factors not often considered in life history evolution. I found that competition, both intraspecific and interspecific, was the most important factor in explaining variation in life history. I also found that the best models were those that included these selective pressures as direct effects as opposed to indirect effects through resource availability. However, it is not clear why competition was supported as a direct effect and future studies are needed to fully understand this aspect. Overall, my research suggests that competition plays an important role in shaping trait evolution, even in traits where it has not been considered. Thus, competition should be included in future studies as it may be an important factor in shaping several traits. I also found that competition in multispecies interactions is more complex than in a simple pairwise interactions, and can be harder to detect due to confounding effects acting in conjunction with competition. My study highlights the importance of competition and of considering multispecies competition to better understand the effects of competition.

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