Managing a software project is an increasingly complex task as it demands the quality of the final product to increase. Thus, e ective management is required from project design to software deployment and maintenance. According to the literature found, Requirements Engineering is the most important phase in terms of final impact on a software project. Changes in software requirements occur throughout the software process, from elicitation and requirements analysis to software operation. Requirements traceability enables one to identify the source and the dependency among software requirements. Studies show that current requirements traceability tools and methods are insu cient which makes it di cult to use traceability in practice. The goal of this work was the proposal of a requirements traceability technique combined with a modeling language and supported by a tool. To achieve this goal, bibliographic review, state-of-the-art research, comparative analysis, questionnaire and interviews were used as research instruments. Initially, an analysis of requirements traceability techniques and evaluation of requirements traceability tools were performed to evaluate if the techniques are used in practice and are being supported by software tools. After these analysis, an event-based traceability technique was proposed using concepts from the SysML modeling language. A software tool was developed to support this technique. Whenever a requirement is modified, the tool notifies stakeholders of such change made to the system requirements through e-mail. The technique and the tool were evaluated by twenty four information technology professionals using a questionnaire based on the TAM model that encompasses the concepts of perceived utility, perceived ease of use and perceived use, and interviews. As a result, the lack of relationship between the techniques and the tools surveyed was observed, and the criterion of automatic communication with stakeholders was not addressed in any evaluated tool. With regard to the proposed technique and tool, a wide acceptance of technique and tool was observed. The acceptance of the proposals was carried out by professionals with varied experiences in software development. / Gerenciar um projeto de software é uma tarefa cada vez mais complexa à medida que as exigências sobre a qualidade do produto final aumentam. Assim, é preciso um gerenciamento eficaz desde a concepção do projeto até a implantação e manutenção do software. Segundo a literatura encontrada, a Engenharia de Requisitos é a fase que possui maior impacto em um projeto de software. As mudanças nos requisitos de software ocorrem ao longo do processo de software, desde a elicitação e análise de requisitos até a operação do software. A rastreabilidade de requisitos possibilita identificar a origem e a dependência entre os requisitos de software. Estudos mostram que as ferramentas e métodos de rastreabilidade de requisitos atuais são insuficientes e dificultam o uso prático da rastreabilidade. O objetivo deste trabalho é a criação de uma técnica de rastreabilidade de requisitos combinada com uma linguagem de modelagem e que seja apoiada por uma ferramenta. Para atingir este objetivo, foram utilizados como instrumentos de pesquisa a revisão bibliográfica, uma pesquisa do tipo estado da arte, análise comparativa, questionário e entrevistas. Inicialmente, foram realizadas análise das técnicas de rastreabilidade de requisitos e avaliação de ferramentas de rastreabilidade de requisitos com intuito de avaliar se as técnicas são utilizadas na prática, e se estão sendo apoiadas por ferramentas de software. Após estas análises, foi proposta uma técnica de rastreabilidade entre requisitos baseada em eventos utilizando conceitos da linguagem de modelagem SysML. Uma ferramenta de software foi desenvolvida para apoiar essa técnica. Sempre que um requisito é modificado, a ferramenta notifica aos stakeholders a alteração realizada nos requisitos do sistema por meio de e-mails. A técnica e a ferramenta foram avaliadas por vinte e quatro profissionais de tecnologia da informação utilizando questionário, baseado no modelo TAM, que engloba os conceitos de utilidade percebida, facilidade de uso percebido e uso percebido, e entrevistas. Como resultado, foram observados a falta de relação entre as técnicas e as ferramentas pesquisadas e que o critério de comunicação automática com stakeholders não foi abordado em nenhuma ferramenta avaliada. Com relação à técnica e ferramenta propostas, observou-se uma ampla aceitação da técnica e da ferramenta. A aceitação das propostas foi realizada por profissionais com experiências variadas em desenvolvimento de software.

Mechatronic design is an enigma. On the one hand, mechatronic products promise enhanced functionality, and better performance at reduced cost. On the other hand, optimizing mechatronic design concepts is a major challenge to overcome during the design process. In the past, less attention has been paid to the life phases of a mechatronic product, and it was assumed that modifications in electronics and software will ensure that the product performs to expectation throughout its life time. However it has been realized that introducing design changes in mechatronics is not easy, since it is difficult to assess the consequences of a design decision, both during the design process of a new product, and during a design modification. It is also realized that there is a strong need to consider the product's life phases during the early phases of product development. Furthermore, it is rather difficult to perform a design optimization since it requires introducing changes across different domains, which is not well supported by the methods and tools available today. This thesis investigates the topic of mechatronic design and attacks some of the major challenges that have been identified regarding the design of mechatronic products. The goal is to provide support to the designers to facilitate better understanding of the consequences of their design choices as early as possible. The work also aims to provide support for assessing alternative design concepts, and for optimizing a design concept based on requirements, constraints and designer preferences at the time of design. The thesis highlights three main challenges related to mechatronic product development: the need for a common language during conceptual design; the inadequate information transfer between engineering domains; and the difficulty in assessing the properties of competing mechatronic concepts. A model-based integration approach is presented, and these key challenges are considered in relation to an integrated modeling and design infrastructure. The approach is illustrated through the design of two mechatronic systems- a two degrees-of-freedom robot, and a hospital bed propulsion system. Initial results provide evidence of good potential for information transfer across mechatronic domains. Although SysML was used for the case studies, some important questions were raised about its suitability as a common language for mechatronics. Suggestions for future work are: to utilize the developed infrastructure and incorporate a capability to model and assess consequences of competing design concepts; provide support for optimizing these concepts; and evaluate the usefulness of the developed infrastructure in a real-world design setting. These efforts should provide ample information to the designer for making adequate decisions during the design process. / QC 20110629

The rise of batteries in the industry, especially Li-ion, is increasing rapidly. Li-ion battery systems are traditionally composed of a particular type of cell chemistry fit to the system needs. Due to the significant differences between chemistries, different cells have different attributes. The thesis explores the potential of a heterogeneous solution to include different cells to find a suitable compromise between different attributes. An electrified passenger train using a homogenous solution was evaluated against a heterogeneous solution consisting of two cell types, NMC and LTO, which have significant differences in attributes.  Simulation with models covering the train kinematics, track characteristics, and battery behaviour generates the thesis results. Validation of simulation results includes comparing previous simulations and the new effects of the heterogeneous solution, which indicate a good fit. Verification of the results encompasses a small-scale experiment with a custom-made physical circuit to observe the proposed solution's actual behaviour and verify model validity, which implies the correctness of models and implementation. The results indicate that a heterogeneous solution is possible within the scope of electrified trains. Furthermore, several trade-offs exist between NMC and LTO cells, especially regarding rate capability, safety and capacity, which confirms the potential of heterogeneous battery systems.

The increasing complexity of systems and the demand for increasing implemented functionalit-ies within the systems necessitate a paradigm shift in development approaches. While traditionalsystems engineering relies heavily on textual documentation, the future calls for a more stream-lined, digital method such as Model-Based Systems Engineering (MBSE). MBSE utilises models tostore data, mitigating textual ambiguity and providing stakeholders with a unified source of inform-ation. Despite its potential, the adoption of MBSE presents challenges because of the need of newpractitioner skill-sets. The thesis investigates the feasibility of implementing an easily adoptable MBSE, using a limitedset of SysML elements and diagrams, approach within the space industry. Through the developmentof guidelines, steps, and goals, a model of an industry-related system is constructed. The createdmodel serves as a demonstration to industry engineers, evaluating the suitability of the proposedguidelines. The thesis concludes the need for maturity of MBSE, its tools, and the need for harmonisationwithin the space industry to establish acceptance among the practitioners. These are the crucialpoints where development and refinements are needed to gain the trust and interest of the end usersof the modelling activities and adopting the proposed methods.i

<p>Is North America vulnerable to widespread electrical blackout from natural or man-made disasters? Yes. Are electric utilities and critical infrastructure (CI) operators prepared to maintain CI operations such as, hospitals, sewage lift stations, food, water, police stations etc., after electrical blackout to maintain National security and sustainability? No. Why? Requirements to prioritize electrical restoration to CI do not exist as a requirement or regulation for electrical distribution operators. Thus, the CI operators cannot maintain services to the public without electricity that provides power for the critical services to function. The problem is that electric utilities are not required to develop or deploy a prioritized systematic plan or procedure to decrease the duration of electrical outage, commonly referred to as blackout. The consequence of local blackout to CI can be multi-billion-dollar financial losses and loss of life for a single outage event attributed to the duration of blackout. This study utilized the review of authoritative literature to answer the question: “Can a plan be developed to decrease the duration of electrical outage to critical infrastructure”. The literature revealed that electric utilities are not required to prioritize electrical restoration efforts and do not have plans available to deploy minimizing the duration of blackout to CI. Thus, this study developed a plan and subsequent model using Model Based System Engineering (MBSE) to decrease the duration of blackout by providing incremental electrical service to CI.</p>

Energy and environmental impacts are two factors that will influence urban region composition in the near future. One emerging issue is the effect on water usage resulting from changes in regional or urban transportation trends. With many regions experiencing stresses on water availability, transportation planners and users need to combine information on transportation-related water consumption for any region and assess potential impacts on local water resources from the expansion of alternative transportation modes. This thesis will focus on use-phase water consumption factors for multiple vehicle modes, energy and fuel pathways, roads, and vehicle infrastructure for a given transportation network. While there are studies examining life cycle impacts for energy generation and vehicle usage, few repeatable models exist for assessing overall water consumption across several transportation modes within urban regions. As such, the question is: is it possible to develop a traceable decision support model that combines and assesses water consumption from transportation modes and related mobility infrastructure for a given mobility network? Based on this, an object-oriented system model of transportation elements was developed using the Systems Modeling Language (SysML) and Model-Based Systems Engineering principles to compare water consumption across vehicle modes for assessing the resiliency of existing infrastructure and water resources. To demonstrate the intent of this model, daily network usage water consumption will be analyzed for current and alternative network scenarios projected by policies regarding the expansion of alternative energy. The model is expected to show variations in water consumption due to fluctuations in energy pathways, market shares, and driving conditions, from which the model should help determine the feasibility of expanding alterative vehicles and fuels in these networks. While spatially explicit data is limited compared to the national averages that are used as model inputs, the analytical framework within this model closely follows that of existing assessments and the reusable nature of SysML model elements allows for the future expansion of additional transportation modes and infrastructure as well as other environmental analyses.

Systems engineering becomes more challenging as system engineers must tackle increasingly growing and complex systems while balancing stakeholder needs, dependability, costs, and much more. Engineering decisions at early stages become important as their impact can affect the product's entire life cycle. Model-Based System Engineering (MBSE) is a way to capture this system complexity and explore how different engineering decisions affect a system. With this in mind, this thesis will explore how MBSE can capture engineering decisions and their impact at early stages of development and what insight can be gained into a system.  This is done by exploratively creating a concept, using it on a toy example to get direct feedback on its performance, and refining the concept before evaluating it in a case study. The case study evaluates the concept in an industrial context through a focus group and receives direct industry feedback. The modelling concept is implemented in Papyrus Eclipse as a Unified Modeling Language (UML) profile to capture concept-specific details and an Eclipse plugin. This implementation is to retrieve and process data from the modelled system. This is used to answer impact questions of choices, such as: "How much does this parameter change if component X is exchanged for another?".The evaluation of the concept was generally positive and gave valuable feedback and possible future directions of the concept. This includes the opinion that a spread sheet gives a better overview of the system and ways to expand the tool though parameterised relations and other suggestions.  The thesis in the end presents, one way that MBSE can be used to support the analysis of early cross-disciplinary models, and two major insights which could be gained, namely risk and constraints.