Modelling and simulation of complex and multi-domain mechanical systems has become of major importance in the last few years to address energy and fuel consumption performance evaluation. The goal is to unify the available modelling languages aiming to improve scalability and easiness of handling complex multi-domain models. Modelica Modelling Language was born in 1997. It has three main features: object-oriented, equation based with non-causal design structure and multi-domain environment. This thesis aims to give an overview of using Modelica on Modelon Impact software to model and simulate a complete 3D wheel loader dynamic system. The project wants to show how the model has been developed focusing on each sub-system implementation. The 3D wheel loader model is designed following the top-down and bottom-up design approaches and focusing on the powertrain sub-system with the engine, transmission and driveline blocks. The combination of the two logics is used to smooth the modelling path and exploit all the benefits. For the simulation experiments, test rig models are implemented to verify the dynamics of individual sub-systems. The model is simulated giving a set of input signals and solving the dynamic equations using different numerical solvers and comparing the elapsed simulation time. The simulation results show that the Radau5ODE explicit solver achieves faster simulation with stable solution given by the variable step size parameter. However, more studies and specific background are needed to update the complexity of the model and compare it with the already existing one. / Modellering och simulering av komplexa mekaniska system med flera domäner har fått stor betydelse under de senaste åren för att utvärdera energi och bränsleförbrukning. Målet är att förena de tillgängliga modelleringsspråken för att förbättra skalbarheten och underlätta hanteringen av komplexa modeller med flera områden. Modelica-modelleringsspråket föddes 1997. Det har tre huvudfunktioner: objektorienterat, ekvationsbaserat med icke-kausal designstruktur och en miljö med flera områden. Syftet med denna avhandling är att ge en översikt över användningen av Modelica i programvaran Modelon Impact för att modellera och simulera ett komplett dynamiskt 3D-system för hjullastare. Projektet vill visa hur modellen har utvecklats med fokus på varje delsystems genomförande. 3D-modellen för hjullastaren har utformats enligt top-down och bottom-up principerna och fokuserar på delsystemet drivlina med motor, transmission och drivlina. Kombinationen av de två logikerna används för att jämna ut modelleringsvägen och utnyttja alla fördelar. För simuleringsförsöken har testriggmodeller införts för att kontrollera dynamiken hos enskilda delsystem. Modellen simuleras med en uppsättning insignaler och de dynamiska ekvationerna löses med hjälp av olika numeriska lösare, varefter den förflutna simuleringstiden jämförs. Simuleringsresultaten visar att den explicita lösaren Radau5ODE ger en snabbare simulering med en stabil lösning som ges av parametern variabel stegstorlek. Det behövs dock fler studier och mer specifik bakgrund för att uppdatera modellens komplexitet och jämföra den med redan existerande modeller.

Architectural documentation is crucial in the development process, as it helps developers understand the system’s architecture and make informed decisions. However, conventional documentation methods are often timeconsuming and error-prone since most of the work is done manually. This becomes even more ambiguous whendealing with complex systems and when requirements are prone to changing during the development process. This thesis addresses these challenges by exploring the potential benefits of utilizing object-oriented documentation tools and plugins to improve the efficiency of writing and maintaining architectural documentationwhile also making sure that the conveyed information is sufficient and understandable for junior developers. Moreover, it investigates the possibility of generating an easy-to-maintain context view with the use of metadatato display architectural information. The thesis employs both a qualitative case study as well as a rapid application development (RAD) approach.The case study involves interviewing junior developers to find patterns in what junior developers look for inregards to understanding a system’s architecture. Using the RAD approach, a prototype system is developedthat utilizes DollarDoc to treat documentation components as objects by being able to refer to these objectsfrom one file to another. The result shows how architectural documentation can be designed to effectively communicate critical aspects of the system’s architecture to junior developers by providing a clear overview of its components. Thiscontributes to a better understanding of the system’s functionality and purpose, leading to increased productivity and engagement. By using object-oriented documentation tools, the documentation structure becomesmore maintainable, allowing for automatic updates and reliable information.

The research is conducted in the area of software methodologies with the emphasis on the integration of legacy systems with the client/server environment. The investigation starts with identifying the characteristics of legacy systems in order to determine the features and technical characteristics required of an integration methodology. A number of existing methodologies are evaluated with respect to their features and technical characteristics in order to derive a synthesis for a generic methodology. This evaluation yields the meta primitives of a generic methodology. The revised spiral model (Boehm,1986; DuPlessis & Vander Wah,1992) is customised to arrive at a software process model which provides a framework for the integration of legacy systems with the client/server environment. The integration methodology is based on this process model. / Computing / M. Sc. (Information Systems)

The focus of the dissertation is on software quality assurance for object-oriented information systems development. A Quality Assurance Reference Model is proposed with aspects dealing with technical and managerial issues. A revised Spiral life cycle model is adopted as well as the Object Modelling Technique. The Quality Assurance Reference Model associates quality factors at various levels, quality criteria and metrics into a matrix framework that may be used to achieve quality assurance for all cycles of the Spiral Model. / Computing / M. Sc. (Information Systems)

The process control domain is intrinsically complex and dynamic. It has proved to be difficult to construct and maintain process control systems under the traditional software development methodologies. Object Orientation is the latest paradigm in software development. The reason for its widespread acceptance is that it allows the application of the principles of hierarchical structuring and component abstraction which is essential in building large systems. It also promotes component reusability which makes systems easier to maintain and modify. For the process control domain, these are important benefits. Furthermore, most process control systems have physical devices which can be modeled naturally as objects with the timing and performance issues of each object directly addressed. A Target System Reference Model which addresses various aspects of the process control domain is proposed within this dissertation. The objective is to provide a frame of reference within which a process control system can function. / Computing / M. Sc. (Computer Science)

Ce mémoire présente un patron d’architecture permettant, dans un contexte orientéobjet, l’exploitation d’objets appartenant simultanément à plusieurs hiérarchies fonctionnelles. Ce patron utilise un reasoner basé sur les logiques de description (web sémantique) pour procéder à la classification des objets dans les hiérarchies. La création des objets est simplifiée par l’utilisation d’un ORM (Object Relational Mapper). Ce patron permet l’utilisation effective du raisonnement automatique dans un contexte d’applications d’entreprise. Les concepts requis pour la compréhension du patron et des outils sont présentés. Les conditions d’utilisation du patron sont discutées ainsi que certaines pistes de recherche pour les élargir. Un prototype appliquant le patron dans un cas simple est présenté. Une méthodologie accompagne le patron. Finalement, d’autres utilisations potentielles des logiques de description dans le même contexte sont discutées. / This master thesis presents a software architectural pattern for use in an object oriented environment to simultaneously access objects in multiple functional hierarchies. A Description Logics (Semantic Web) reasoner is used to classify the objects in the hierarchies. Object creation is simplifed by the use of an ORM - Object Relational Mapper. The pattern effectively allows automatic reasoning procedures to be used in an enterprise application context. All concepts required to understand the architectural pattern and the tools are presented. Usage conditions for the pattern are discussed and research projects are presented to widen the pattern’s applicability. A prototype applying the pattern on a simple problem is presented. A methodology is also presented. Finally, other potential uses of Description Logics based automatic reasoning procedures are discussed.

Ce mémoire présente un patron d’architecture permettant, dans un contexte orientéobjet, l’exploitation d’objets appartenant simultanément à plusieurs hiérarchies fonctionnelles. Ce patron utilise un reasoner basé sur les logiques de description (web sémantique) pour procéder à la classification des objets dans les hiérarchies. La création des objets est simplifiée par l’utilisation d’un ORM (Object Relational Mapper). Ce patron permet l’utilisation effective du raisonnement automatique dans un contexte d’applications d’entreprise. Les concepts requis pour la compréhension du patron et des outils sont présentés. Les conditions d’utilisation du patron sont discutées ainsi que certaines pistes de recherche pour les élargir. Un prototype appliquant le patron dans un cas simple est présenté. Une méthodologie accompagne le patron. Finalement, d’autres utilisations potentielles des logiques de description dans le même contexte sont discutées. / This master thesis presents a software architectural pattern for use in an object oriented environment to simultaneously access objects in multiple functional hierarchies. A Description Logics (Semantic Web) reasoner is used to classify the objects in the hierarchies. Object creation is simplifed by the use of an ORM - Object Relational Mapper. The pattern effectively allows automatic reasoning procedures to be used in an enterprise application context. All concepts required to understand the architectural pattern and the tools are presented. Usage conditions for the pattern are discussed and research projects are presented to widen the pattern’s applicability. A prototype applying the pattern on a simple problem is presented. A methodology is also presented. Finally, other potential uses of Description Logics based automatic reasoning procedures are discussed.

Research has shown that there are gaps in knowledge between newly hired and experienced professionals and that some of these gaps are related to concepts, such as the concepts of object orientation. This problem, and the fact that most computer science majors want to work in the software industry, leads to questions regarding why these gaps exist and how students can be better prepared for their future careers. Against this background, this thesis addresses two theme-based perspectives that focus on students' views of concepts in Computer Science. The first theme-based perspective investigated the existence of potential Threshold Concepts in Computer Science. Such concepts should be troublesome, transformative, irreversible, and integrative. Qualitative methods have been mainly used and empirical data have been collected through semi-structured interviews, concept maps, and written stories. The results identified two Threshold Concepts, suggested several more, and then described the ways in which these concepts have transformed students. The second theme-based perspective took a phenomenographic approach to find the variation in how students understand concepts related to the software profession. Data were collected via semi-structured interviews. In one study the interviews were held in connection with role-playing where students took on the role of a newly hired programmer. The results show a variety of ways to experience the addressed phenomena in the student collective, ranging from superficial views that often have a practical nature to more sophisticated understandings that reflect a holistic approach, including a professional point of view. Educators can use the results to emphasize concepts that are important from students' perspectives. The phenomenographic outcome spaces can help teachers to reflect upon their own ways of seeing contrasted with student conceptions. I have indicated how variation theory can be applied to open more sophisticated ways of seeing, which in this context stresses the professional aspects to help students prepare for becoming professional software developers.

The research is conducted in the area of software methodologies with the emphasis on the integration of legacy systems with the client/server environment. The investigation starts with identifying the characteristics of legacy systems in order to determine the features and technical characteristics required of an integration methodology. A number of existing methodologies are evaluated with respect to their features and technical characteristics in order to derive a synthesis for a generic methodology. This evaluation yields the meta primitives of a generic methodology. The revised spiral model (Boehm,1986; DuPlessis & Vander Wah,1992) is customised to arrive at a software process model which provides a framework for the integration of legacy systems with the client/server environment. The integration methodology is based on this process model. / Computing / M. Sc. (Information Systems)

The focus of the dissertation is on software quality assurance for object-oriented information systems development. A Quality Assurance Reference Model is proposed with aspects dealing with technical and managerial issues. A revised Spiral life cycle model is adopted as well as the Object Modelling Technique. The Quality Assurance Reference Model associates quality factors at various levels, quality criteria and metrics into a matrix framework that may be used to achieve quality assurance for all cycles of the Spiral Model. / Computing / M. Sc. (Information Systems)