Afin de rendre les piles à combustible à membrane échangeuse de protons viables économiquement dans le domaine automobile, des problèmes de durabilité et de coût sont à résoudre. La compréhension et le contrôle des dégradations à l'intérieur de la cellule et surtout de l'AME sont toujours le centre d’intérêt de nombreux laboratoires mais aussi d'industriels. Les milliers d'arrêt-démarrages subis par la pile provoquent une importante corrosion du support carbone. Le platine utilisé étant un catalyseur onéreux, la modélisation numérique permet l'analyse de phénomènes à moindre coût.Dans ces travaux, deux modèles ont été développés afin de modéliser les phases transitoires que sont les arrêt-démarrages. Tout d'abord, une étude sur les performances de la pile a été effectuée en utilisant le modèle. Le couplage entre les modèles le long du canal et dent/canal est introduit. Ensuite, une analyse des phénomènes se déroulant durant les arrêt-démarrages est effectuée. Des phases temporelles sont proposées afin de découper ces différents phénomènes. Le mécanisme des courants inverses (durant lequel la corrosion du carbone apparaît) est minutieusement détaillé avec l'aide du modèle. L'accent est porté sur les hétérogéneités de dégradations apparaissant entre l'entrée et la sortie mais aussi entre le canal et la dent. Enfin, le modèle est utilisé afin de simuler et proposer des stratégies de mitigations. Les tendances attendues par la littérature sont confirmées mais aussi évaluées. Parmi les idées suggerées, l'optimisation du design dent/canal tout au long du canal est proposée afin de limiter les dégradations. / In order to make Proton Exchange Membrane Fuel Cells economically viable for an automotive application, durability and cost problems have to be addressed. Understanding and mitigating degradations inside the cell especially in the MEA are still the focus of several laboratories and also industrials. The several thousands startups and shutdowns that the fuel cell underwent induce severe corrosion of the carbon support. As the catalyst used is expensive, namely platinum, modeling is a great asset to comprehend and analyze this phenomenon costwise.In this work, two models were developed for modeling the transient phases that are the startup and shutdown. First a performance study is presented to validate the use of the model and to introduce the coupling between the along the channel model and the rib/channel model. Then an analysis of the phenomena occurring during the startup (and shutdown) is carried out. Phases are suggested to break down the different phenomena. The reverse-current decay mechanism, when carbon corrosion occurs, is thoroughly detailed using the model. Degradation heterogeneities are highlighted whether they are between inlet and outlet or rib and channel. Finally the model is used to emulate and suggest mitigation strategies. Degradation trends are confirmed and evaluated. New ideas like an original flow field design are tested to mitigate degradation.

This thesis puts forth the means of a strategic approach to address a persistent problem in the energy system and in this way, to transition the built environment to a future state that is more exergy-aware to curb CO2 emissions. Such a vision is made possible by the six-fold contributions of the research work: I) An analytical model is developed, which for the first time, formulates the CO2 emissions that are compounded in the energy system as a function of the systematic failures to match the supply and demand of exergy. This model is namely the Rational Exergy Management Model or REMM. II) REMM is then applied to analyze the pathways in which it is possible to lead the built environment into addressing structural overshoots in its exergy supply to curb CO2 emissions. The cases that embody these pathways are also analyzed over a base case, including cases for sustainable heating and cooling. III) New tools are designed to augment decision-making and exemplify a paradigm shift in the more rational usage of exergy to curb CO2 emissions. These include a scenario-based analysis tool, new options for CO2 wedges, and a multi-fold solution space for CO2 mitigation strategies based on REMM. IV) The concept of a net-zero exergy building (NZEXB) is developed and related to REMM strategies as the building block of an exergy-aware energy system. The target of a NZEXB is further supported by key design principles, which address shortcomings in state-of-the-art net-zero design. V) A premier building that deployed the key design principles to integrate building technology in an innovative, exergy-aware design and received LEED Platinum is analyzed on the basis of the NZEXB target. The results validate that this building boosts net self-sufficiency and curbs compound CO2 emissions, which are then presented in a proposed scheme to benchmark and/or label future NZEXBs. VI) Based on the scalability of the best-practices of the NZEXB ready building, the means to realize a smarter energy system that has exergy-aware relations in each aspect of the value chain to curb CO2 emissions are discussed. This includes a target for such a network at the community level, namely a net-zero exergy community (NZEXC). As a whole, the results of the thesis indicate that the strategic approach as provided by REMM and the NZEXB target of the research work has the potential to steer the speed and direction of societal action to curb CO2 emissions. The thesis concludes with a roadmap that represents a cyclical series of actions that may be scaled-up at various levels of the built environment in a transition to be in better balance with the Planet. / QC 20111014

The equity crowdfunding market has since the financial crisis in 2008 become an important source of alternative financing in Sweden. The equity crowdfunding platforms constitute the market and are responsible for governing the investment relationships. However, the market is not regulated, and in the spring of 2018 the Swedish government proposed regulatory changes for the platforms to impact the problem of information asymmetry. There are different approaches on how to impact the problem, and therefore the thesis sets out to understand how the equity crowdfunding platforms within the Swedish market work to impact information asymmetry.  Empirical data has been collected from five different Swedish equity crowdfunding platforms. Semi-structured interviews were conducted with individuals whose work is connected to governing and impacting information asymmetry. The analysis of the empirical findings identifies five main reasons for the arise of information asymmetry and the platforms work to control and reduce information asymmetry by mitigation strategies, investor communication and effective signaling. The findings indicate that there is a trade-off between controlling information asymmetry and making the financing method accessible within the market. This study contributes to the understanding of how equity crowdfunding platforms work to impact information asymmetry within the Swedish market.

O clima é um dos fatores ambientais que impõe os maiores riscos para a atividade agrícola, sendo responsável pelas oscilações e frustrações das safras no Brasil. Em cenário de mudanças climáticas, os atuais níveis de produtividade do milho de 1ª e de 2ª safra deverão ser alterados. Para se avaliar tais impactos, os modelos de simulação de culturas possibilitam estimar o crescimento, o desenvolvimento fenológico e a produtividade das culturas sob ampla gama de condições ambientais e de manejo, sendo, portanto, ferramentas eficientes para esse tipo de estudo. Considerando os possíveis impactos das mudanças climáticas na produtividade da cultura do milho, o presente estudo teve por objetivos: i) realizar preenchimento de falhas em séries de dados meteorológicos e, gerar séries sob projeções futuras do clima a curto (2010- 2039), médio (2040-2069) e longo (2070-2099) prazos, para os cenários de emissão intermediária (RCP4.5) e de alta emissão (RCP8.5); ii) calibrar e validar os modelos DSSAT/CERES-Maize e MONICA para simular a produtividade do milho de 1ª e de 2ª safra, e analisar a sensibilidade desses modelos, identificando os fatores de maior influência na produtividade do milho; iii) aplicar o modelo DSSAT/CERES-Maize, para determinar a produtividade do milho de 1ª e de 2ª safra, em condições de clima atual e futuro, e avaliar possíveis estratégias de manejo, de forma individual e combinada, como épocas de semeadura, ciclo da cultivar, irrigação e adubação nitrogenada, para minimização dos possíveis impactos. Para o preenchimento de falhas em séries de dados meteorológicos, o método de Bristow- Campbell (estimação da radiação solar), e a base em ponto de grade XAVIER foram as que apresentaram melhor desempenho. As projeções de clima futuro evidenciaram condições de clima mais quente, com redução no total acumulado de chuva nas regiões Norte-Nordeste e aumento no Sul do país, e as regiões Sudeste e Centro-Oeste configurando como áreas de transição. Os modelos DSSAT/CERES-Maize e MONICA apresentaram índice de desempenho (c) muito bom para ambas as safras, na estimação da produtividade do milho, com EAM inferior a 450 e 350 kg ha-1 na 1ª e na 2ª safra, respectivamente. Para as estimativas por conjunto, os valores de c foram avaliados como ótimos para as duas safras, com EAM caindo para 276 e 194 kg ha-1, na 1ª e na 2ª safra, respectivamente. Ambos os modelos mostraram sensibilidade às alterações climáticas e de adubação, porém com o modelo DSSAT/CERES-Maize se mostrando mais adequado para estudos de impactos de mudanças climáticas na cultura do milho. As simulações sob clima futuro com o modelo DSSAT/CERES-Maize, mostraram perdas de produtividade em relação aos atuais níveis, variando de 41 a 63% para milho da 1ª safra, e de 58 a 65% para o milho da 2ª safra, com as estratégias de manejo quanto a data de semeadura, ciclo da cultivar, irrigação e adubação nitrogenada mostrando redução das perdas e até mesmo ganhos de produtividade quando adotadas em condições de clima futuro. / Climate is one of the major environmental factors that impose the greatest risks for the agricultural activity, being responsible for the oscillations and frustrations of the crops in Brazil. In a scenario of climate change, the current yield levels of maize growing in-season and offseason should be impacted. In order to evaluate such impacts, crop simulation models allow estimating the growth, phenological development and yield under a wide range of environmental and crop management conditions, being efficient tools for applying to this kind of study. Considering the possible impacts of climate change on maize crop yield, the present study had as objectives: i) to fill gaps in meteorological data series and to generate series under future climate projections in the short (2010-2039), medium (2040-2069) and long (2070-2099) terms periods, for the intermediate emission (RCP4.5) and high emission (RCP8.5) scenarios; ii) to calibrate and validate the DSSAT/CERES-Maize and MONICA models to simulate inseason and off-season maize yield and to analyze the sensitivity of these models, identifying the factors that have the major influence on yield; (iii) to apply the DSSAT/CERES-Maize model to determine maize yield in the in-season and off-season, under current and future climate conditions, and evaluate possible crop management strategies, individually and in combination, such as sowing dates, crop cycle, irrigation and nitrogen fertilization, to minimize possible negative impacts. In order to fill the gaps in meteorological data series, the Bristow- Campbell method (for solar radiation estimation) and the XAVIER daily gridded database were the ones that presented the best performance. The projections of future climate showed warmer climate conditions, with a reduction in the rainfall amounts in the North-Northeast and an increase in the South of the country, with the Southeast and Center-West regions representing transition areas. Both DSSAT/CERES-Maize and MONICA models showed very good performance index (c) in the estimation of maize yield for both seasons, with MAE lower than 450 and 350 kg ha-1 during the in-season and off-season, respectively. For the ensemble estimation, the estimation improve, with optimal performance index, with MAE falling to 276 and 194 kg ha-1, for in-season and off-season maize growing, respectively. Both models showed sensitivity to climate change and fertilization, but with the DSSAT/CERES-Maize model being more suitable for studies of climate change impacts on maize crop. The simulations under future climate with DSSAT/CERES-Maize model showed a yield loss in relation to current levels, ranging from 41 to 63% for in-season, and from 58 to 65% for off-season, with management strategies regarding sowing date, cultivar cycle, irrigation and nitrogen fertilization, showing reduction of losses and even yield gains when adopted in the future climate conditions.

[pt] Apesar do avanço das discussões sobre variedade de produtos e de seu impacto na complexidade em sistemas de produção, pouco se sabe sobre como o gerenciamento dessa variedade difere entre os mercados emergentes e estabelecidos. Esta dissertação visa preencher esta lacuna por meio da comparação entre (1) a variedade de produto oferecida pelas indústrias automobilísticas no Brasil e na Europa e (2) entre as estratégias utilizadas pelas montadoras de cada um destes mercados para mitigar os efeitos adversos da variedade de produto. A análise exploratória utiliza dados secundários obtidos na literatura e em montadoras da indústria automobilística e dados primários coletados por meio de entrevistas com gerentes destas empresas. A amostra de veículos considerados na análise representa 62% e 95% dos mercados europeu e brasileiro, respectivamente. Apesar de diversas semelhanças entre as duas indústrias, os resultados da pesquisa apontam para diferenças significativas na variedade de produto oferecida em ambos os mercados e nas estratégias de mitigação adotadas, apresentando assim indícios de que a realidade automobilística brasileira não pode ser considerada como uma continuação da realidade européia, merecendo assim estudos próprios. / [en] While the discussion of product variety has advanced into assessing the impacts of complexity induced into the manufacturing system, little is known how the management of this variety differs between emerging and established markets. This dissertation aims to address this gap by comparing the product variety offered in the Brazilian and European automotive industries, as well as the respective strategies used by the vehicle manufacturers to mitigate the negative effects of product variety. The exploratory analysis uses secondary data collected in the literature and in automotive manufacturers and primary data collected in interviews with managers of these manufacturers. The overall sample of vehicles considered in the analysis represent 62% and 95% of the European and Brazilian markets, respectively. In spite of the similarities that are present in both markets, the research results point to significant differences in the variety offered in both markets, as well as in the mitigation strategies adopted, what gives us material to believe that the Brazilian automotive reality can not be considered as a continuation of the European reality, deserving specific studies for Brazil.

Context. Global Software Development (GSD) is the plan of action in which software development is performed under temporal, political, organizational and cultural boundaries. Offshore outsourced software development is the part of GSD, which refers to the transfer of certain software development activities to an external organization in another country. The primary factors driving offshore outsourced software development are low cost, access to a large pool of skilled laborers, increased productivity, high quality, market access and short development cycle. Requirements engineering (RE) and especially requirements elicitation is highly affected by the geographical distribution and multitude of stakeholders. Objectives. The goal of conducting this study is to explore the challenges and solutions associated with requirements elicitation phase during offshore software projects, both in research literature and in industrial practice. Moreover, this study examines that which of the challenges and practices reported in literature can be seen in industrial practice. This helped in finding out the similarities and differences between the state of art and state of practice. Methods. Data collection process has been done through systematic literature review (SLR) and web survey. SLR has been conducted using guidelines of Kitchenham and Charters. During SLR, The studies have been identified from the most reliable and authentic databases such as Compendex, Inspec (Engineering village) and Scopus. In the 2nd phase, survey has been conducted with 391 practitioners from various organizations involved in GSD projects. In the 3rd phase, qualitative comparative analysis has been applied as an analysis method. Results. In total 10 challenges and 45 solutions have been identified from SLR and survey. Through SLR, 8 challenges and 22 solutions have been identified. While through industrial survey, 2 additional challenges and 23 additional solutions have been identified. By analyzing the frequency of challenges, the most compelling challenges are communication, control and socio-cultural issues. Conclusions. The comparison between theory and practice explored the most compelling challenges and their associated solutions. It is concluded that socio-cultural awareness and proper communication between client and supplier organization’s personnel is paramount for successful requirements elicitation. The scarcity of research literature in this area suggests that more work needs to be done to explore some strategies to mitigate the impact of additional 2 challenges revealed through survey. / 0046 707123094

Context: Distributed software development has become a most desired way of software development. Application of agile development methodologies in distributed environments has taken a new trend in developing software due to its benefits of improved communication and collaboration. Teamwork is an important concept that agile methodologies facilitate and is one of the potential determinants of team performance which was not focused in distributed agile software development. Objectives: This research shed a light on the topic of teamwork in the context of distributed agile software development. The objectives are to identify the factors contributing teamwork of distributed agile teams along with the dependencies between the factors. And, as it is not without challenges to work with unity in a heterogeneous environment, identification of challenges related to teamwork factors of distributed agile teams along with the mitigation strategies is an another objective. Methods: A systematic literature review (SLR) was employed to identify the teamwork factors along with their dependencies and corresponding challenges and mitigation strategies of each teamwork factor from state-of-the-art literature. Quasi-gold standard method was employed as search strategy in SLR to find out the primary studies representing the objective under investigation. Further a survey was conducted with industrial practitioners working in distributed agile projects to validate the findings from state-of-the-art literature. Results: A total of 13 teamwork factors (i.e. team orientation, shared leadership, mutual performance monitoring, backup behavior, feedback, team autonomy, team learning, coordination, communication, trust, collective culture, ease of use of technology, team familiarity), a set of nine dependencies between the teamwork factors and 45 challenges and 41 mitigation strategies related to the teamwork factors were identified from state-of-the-art literature. From survey result, communication, coordination, trust and team orientation were identified as four most important teamwork factors for distributed agile teams. Out of nine dependencies, seven were supported and two were not supported by the practitioners of distributed agile projects. Additionally, nine challenges and 12 mitigation strategies were identified through survey. Conclusions: From this study, we conclude that communication is the top most important factor for successful teamwork of distributed agile teams. And, unlike its prime importance in distributed software development for getting teams work together, trust was identified with a third priority for successful teamwork of distributed agile teams. Similar to the findings of the agile teams, team autonomy was identified with least importance towards the successful teamwork of distributed agile teams. Results of dependencies show that there is need for future research to explore all the dependencies between the teamwork factors. Furthermore, there are teamwork factors with no challenges and mitigation strategies being identified in state-of-the-art literature but later, through survey it was found that practitioners are facing the challenges for that particular teamwork factor. Though, this study identified those missed challenges, due to the limited number of participants involved in the survey, we cannot conclude that these were the only challenges faced in relation to the teamwork. Hence, there is a need to have a dedicated investigation in exploring all the challenges and mitigation strategies, such that it would help the distributed agile teams in attaining the fruitful interactions between them. / H.no. 5-5-289, Prashanth Nagar, Vanasthalipuram, Hyderabad-500070, Andhra Pradesh. India

There is increasing concern about potential climate-driven regime shifts– large abrupt shifts in social-ecological systems that could have large impacts onecosystems services and human well-being. This paper aims to synthesize the potentialpathways for building resilience to such regime shifts. Ten examples from the RegimeShift Database provided the cases for analysis. Causal loop diagrams were used toanalyze feedback mechanisms at different scales and identify “leverage points” –places to intervene in the system in order to build resilience. Sixteen of these leveragepoints were identified, most of which relate to agricultural management. Mostfeedback mechanisms include at least one leverage point highlighting the potential forbuilding resilience to climate-induced regime shifts. The most common leverage pointsidentified in our analyses were vegetation cover, algae volume and atmospherictemperature. These leverage points were compared to mitigation strategies discussedby the IPCC. This comparison indicates that current climate change mitigationstrategies do not alter most of the leverage points directly. This suggests that IPCCstrategies should be broadened in order to reduce the risk of regime shifts, and theassociated impacts on human well-being.

Context: In recent years, software development teams have been adopting agile methodologies like Scrum to enhance productivity and collaboration. However, with the outbreak of COVID-19, remote working conditions have become the new norm. This shift has posed a challenge for software development teams as they struggle to maintain the same level of productivity and collaboration while working remotely. Agile methodologies like Scrum, which emphasize teamwork, communication, and collaboration, are particularly affected by remote work conditions. One critical factor that affects agile teams’ effectiveness is team familiarity, which is the degree of mutual understanding among team members. High team familiarity can lead to better communication, coordination, and performance. Objectives: The main aim of this research is to investigate the effects of geographical dispersion on team familiarity in Scrum teams due to pandemic restrictions. The research aims to identify the facets that contribute to the concept of team familiarity, investigate how geographical dispersion has affected team familiarity during the pandemic, and explore how Scrum practices have been impacted by changes in team familiarity under remote working conditions. Methods: The research employed a literature review as a research method and interviews as a data collection technique. The first phase involved conducting a comprehensive literature review by analyzing various research papers using the forward snowballing technique to identify the facets contributing to the concept of team familiarity. In the second phase, semi-structured interviews were conducted with 12 software professionals from various software companies who had experience working in Scrum teams during the pandemic. The interview questions focused on how remote working conditions had affected team familiarity and Scrum practices. The data collected during the interviews were analyzed using a deductive thematic analysis, which guided the identification of common patterns and themes. Results: From the literature review, nine facets of team familiarity were identified: Shared work experience, Communication, Team coordination, Team cohesion, Interpersonal knowledge, Shared knowledge, Trust, Team collaboration, and Member diversity. The interview data revealed that the geographical dispersion did pose a few challenges due to the remote work setup and had negatively affected team familiarity. The correlation between team familiarity facets and scrum practices was also explored, along with how they were affected due to geographical dispersion. However, the interviewees suggested several strategies to mitigate the challenges posed by geographical dispersion, such as regular communication and virtual team-building activities.  The results of the literature review were then compared with the interview results to determine the consistency of the findings. The comparison showed that most of the team familiarity facets identified in the literature review were also relevant to the interviewee's experiences. One important theme that emerged from the comparison of the literature review and interview findings is the interdependence of team familiarity facets, where a change in one facet could affect other facets as well. Trust and communication were found to be the most interconnected facets, with links to other team familiarity facets. Conclusions: This research highlights the importance of team familiarity in Scrum teams and the effect of geographical dispersion on team familiarity. The study identified nine facets that contribute to the concept of team familiarity and discussed their interdependence. The research findings suggest that mitigation strategies can help maintain team familiarity under remote work conditions. It was also concluded that maintaining team familiarity is crucial for effective Scrum practices and team performance. Organizations should consider these factors while implementing Scrum practices in geographically dispersed teams. The study recommends further research to explore the impact of team familiarity on other aspects of team performance. Moreover, the scope of the research could be expanded to include other agile methodologies aside from Scrum. Additionally, investigating the role of leadership in promoting team familiarity and collaboration in geographically dispersed Scrum teams is another potential avenue for future research.

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