<p>Requirements Engineering (RE) is nowadays considered to be an activity, that aims at supporting the whole lifecycle of an information system by: eliciting, documenting, validating, and managing the requirements of the system. This thesis aims at providing an overview of the area of Requirements Management (RM) and to identify important and interesting issues or areas where further research is needed.</p><p>RM includes two major areas; organising requirements and requirements change management. Organising requirements is concerned with structuring the requirements and storing additional relevant information about them e.g. attributes and traceability information. Requirements change management is concerned with dealing with changing requirement in a systematic way i.e. making informed decisions whether to implement a certain change or not, and support the implementation of approved changes.</p><p>In order to provided a broader view of RM, the literature study were complemented by an interview study of how RM is conducted in practice. This interview study shows that the effort resources spent on RM differs substantially between different organisations. Various reasons for these discrepancies are elaborated in the work, but one of the main reasons are the type of software development that is conducted in the organisation. There is a tendency that organisations that develop software products and continuously releases new versions of there products are more likely to spend resources on RM, compared with organisations that develop customers specific solutions in one shoot projects. The need to reuse requirements and knowledge, as well as the maturity of the RE/RM process, are other factors that affects the resources spent on RM. The RM activities performed in practice are concordant with the activities found in literature.</p><p>A number of areas where further research is needed were identified: requirements change management, dependencies between requirements, RM tools, and information management</p>

<p>Ett effektivt användande av ett informationssystem förbättrar informationshanteringen inom en verksamhet. För att ett informationssystem ska kunna fungera effektivt krävs att det motsvarar de krav som ställts på informationssystemet av olika intressenter.</p><p>Requirements Engineering (RE) är en viktig del av systemutvecklingsprocessen för att kunna säkerställa en väl fungerande kravhantering. Use case är en teknik som kan användas som hjälpmedel i RE-processen för att identifiera och dokumentera krav.</p><p>Syftet med detta examensarbete är att undersöka om use case är tillräcklig som enda teknik för att identifiera och dokumentera krav samt vilka eventuella kompletterande tekniker som används bland systemutvecklare. Resultatet av undersökningen visar att use case-tekniken inte är tillräcklig utan måste kompletteras med andra tekniker för att möjliggöra att samtliga krav kan identifieras och dokumenteras.</p>

<p>Examensarbetets frågeställning berör användarnas medverkan i Requirements Engineering (RE). Under RE-fasen skall samtliga krav på det kommande systemet tas fram från intressenterna. En viktig intressentgrupp i kravutvinningsarbetet är de kommande användarna av systemet. Resultatet av RE-fasen är en viktig faktor som påverkar hela den fortsatta utvecklingsprocessen samt hur lyckat det slutliga systemet blir.</p><p>Detta examensarbete innebär en undersökning av vad användarrepresentanterna anser om use case-modelleringen i RE-processen. Undersökningen har påvisat att användarrepresentanterna är positiva till use case-modellering som arbetsmetod för att kartlägga kraven. För att besvara examensarbetets frågeställning har intervjuer med användarrepresentanter genomförts och de har givet vid handen att use case till viss del underlättar kommunikationen, men att det finns ett antal faktorer som försvårar och minskar användarens möjlighet att medverka i arbetet med use case-modelleringen.</p><p>Undersökningen utförs genom en fallstudie inom Volvo Information Technology och de medverkande respondenterna kommer från tre olika projekt av varierande storlek.</p>

<p>Detta examensarbete ger en introduktion till området systemutveckling. Kravhantering har i alla tider varit en viktig del i systemutveckling. För att kunna lyckas med kravhanteringen under ett systemutvecklingsprojekt är det viktigt att använda sig av rätt teknik. En teknik som finns för att kunna hantera de krav som ställs på ett system är Use Case som härstammar från UML. Syftet med detta examensarbete var att ta reda på de för och nackdelar som har upplevts av användare som har arbetat med Use Case i samband med kravhantering. Presentation i detta examensarbete sker genom metoden intervju samt litteraturstudier. Det material som bearbetats fram via intervjuerna har analyserats med hjälp av olika litteraturer för att ge en klar bild av problemställningen. Resultatet visar att Use Case är en omtyckt teknik som innehar både fördelar och nackdelar där fördelarna överväger nackdelarna.</p>

Das Projekt TESSI beschäftigt sich mit der Entwicklung eines Verfahrens und eines CASE-Werkzeugs zur Analyse von Anforderungstexten und dem parallelen Entwurf eines objektorientierten Modells. Veränderte Anforderungen und geplante Erweiterungen machten eine Überarbeitung der Version 1.1 des Programms TESSI notwendig. Diese Diplomarbeit beschreibt das Reengineering der Altsoftware und den Entwurf sowie die Implementierung der neuen Version 2.0 von TESSI.

Zugl.: Zürich, Univ., Diss., 2009

Today, it is well known that missing, incomplete or inconsistent requirements lead to faulty software designs, implementations and tests resulting in software of improper quality or safety risks. Thus, an improved Requirements Engineering contributes to safer and better-quality software, reduces the risk of overrun time and budgets and, most of all, decreases or even eliminates the risk for project failures. One significant problem requirements engineers have to cope with, are inconsistencies in the Software Requirements Specification. Such inconsistencies result from the acquisition, specification, and evolution of goals and requirements from multiple stakeholders and sources. In order to regain consistency, requirements information are removed from the specification which often leads to incompleteness. Due to this causal relationship between consistency, completeness and correctness, we can formally improve the correctness of requirements knowledge by increasing its completeness and consistency. Furthermore, the poor quality of individual requirements is a primary reason why so many projects continue to fail and needs to be considered in order to improve the Software Requirements Specification. These flaws in the Software Requirements Specification are hard to identify by current methods and thus, usually remain unrecognised. While the validation of requirements ensures that they are correct, complete, consistent and meet the customer and user intents, the requirements engineer is hardly supported by automated validation methods. In this thesis, a novel approach to automated validation and measurement of requirements knowledge is presented, which automatically identifies incomplete or inconsistent requirements and quality flaws. Furthermore, the requirements engineer is guided by providing knowledge specific suggestions on how to resolve them. For this purpose, a requirements metamodel, the Requirements Ontology, has been developed that provides the basis for the validation and measurement support. This requirements ontology is suited for Goal-oriented Requirements Engineering and allows for the conceptualisation of requirements knowledge, facilitated by ontologies. It provides a huge set of predefined requirements metadata, requirements artefacts and various relations among them. Thus, the Requirements Ontology enables the documentation of structured, reusable, unambiguous, traceable, complete and consistent requirements as demanded by the IEEE specification for Software Requirement Specifications. We demonstrate our approach with a prototypic implementation called OntoReq. OntoReq allows for the specification of requirements knowledge while keeping the ontology invisible to the requirements engineer and enables the validation of the knowledge captured within. The validation approach presented in this thesis is capable of being applied to any domain ontology. Therefore, we formulate various guidelines and use a continuous example to demonstrate the transfer to the domain of medical drugs. The Requirements Ontology as well as OntoReq have been evaluated by different methods. The Requirements Ontology has been shown to be capable for capturing requirements knowledge of a real Software Requirements Specification and OntoReq feasible to be used by a requirements engineering tool to highlight inconsistencies, incompleteness and quality flaws during real time requirements modelling.

Requirements engineers have to elicit, document, and validate how stakeholders act and interact to achieve their common goals in collaborative scenarios. Only after gathering all information concerning who interacts with whom to do what and why, can a software system be designed and realized which supports the stakeholders to do their work. To capture and structure requirements of different (groups of) stakeholders, scenario-based approaches have been widely used and investigated. Still, the elicitation and validation of requirements covering collaborative scenarios remains complicated, since the required information is highly intertwined, fragmented, and distributed over several stakeholders. Hence, it can only be elicited and validated collaboratively. In times of globally distributed companies, scheduling and conducting workshops with groups of stakeholders is usually not feasible due to budget and time constraints. Talking to individual stakeholders, on the other hand, is feasible but leads to fragmented and incomplete stakeholder scenarios. Going back and forth between different individual stakeholders to resolve this fragmentation and explore uncovered alternatives is an error-prone, time-consuming, and expensive task for the requirements engineers. While formal modeling methods can be employed to automatically check and ensure consistency of stakeholder scenarios, such methods introduce additional overhead since their formal notations have to be explained in each interaction between stakeholders and requirements engineers. Tangible prototypes as they are used in other disciplines such as design, on the other hand, allow designers to feasibly validate and iterate concepts and requirements with stakeholders. This thesis proposes a model-based approach for prototyping formal behavioral specifications of stakeholders who are involved in collaborative scenarios. By simulating and animating such specifications in a remote domain-specific visualization, stakeholders can experience and validate the scenarios captured so far, i.e., how other stakeholders act and react. This interactive scenario simulation is referred to as a model-based virtual prototype. Moreover, through observing how stakeholders interact with a virtual prototype of their collaborative scenarios, formal behavioral specifications can be automatically derived which complete the otherwise fragmented scenarios. This, in turn, enables requirements engineers to elicit and validate collaborative scenarios in individual stakeholder sessions – decoupled, since stakeholders can participate remotely and are not forced to be available for a joint session at the same time. This thesis discusses and evaluates the feasibility, understandability, and modifiability of model-based virtual prototypes. Similarly to how physical prototypes are perceived, the presented approach brings behavioral models closer to being tangible for stakeholders and, moreover, combines the advantages of joint stakeholder sessions and decoupled sessions. / Anforderungsingenieure erheben, dokumentieren und validieren wie Bedarfsträger in einzelnen und gemeinsamen Aktivitäten die Ziele ihrer kollaborativen Szenarios erreichen. Auf Grundlage von Angaben darüber, wer warum mit wem zusammen was erledigt, kann anschließend ein Softwaresystem spezifiziert und umgesetzt werden, welches die Bedarfsträger bei der Durchführung ihrer Abläufe unterstützt. Um Anforderungen verschiedener (Gruppen von) Bedarfsträger zu erfassen und zu strukturieren, werden szenariobasierte Ansätze genutzt und erforscht. Die Erhebung und Validierung von Anforderungen, die kollaborative Szenarios abdecken, ist dennoch kompliziert, da derartige Informationen hochgradig verknüpft, fragmentiert und über mehrere Bedarfsträger verteilt sind, wodurch sie nur in Gruppensitzungen effizient erhoben und validiert werden können. In Zeiten global verteilter Firmen ist die Planung und Durchführung solcher Workshops mit Gruppen von Bedarfsträgern nur selten praktikabel. Mit einzelnen Bedarfsträgern zu sprechen ist hingegen oft realisierbar, führt aber zu fragmentierten, unvollständigen Szenariobeschreibungen. Durch eine Vielzahl von Einzelgesprächen mit wechselnden Bedarfsträgern kann diese Fragmentierung aufgelöst werden – dies ist aber eine fehleranfällige und zeitaufwändige Aufgabe. Zwar bieten formale Modellierungsmethoden z.B. automatische Konsistenzchecks für Szenarios, doch führen derartige Methoden zu Mehraufwand in allen Gesprächen mit Bedarfsträgern, da diesen die verwendeten formalen Notationen jedes Mal erläutert werden müssen. Handfeste Prototypen, wie sie in anderen Disziplinen eingesetzt werden, ermöglichen es Designern, ihre Konzepte und erhobenen Anforderungen ohne viel Aufwand mit Bedarfsträgern zu validieren und zu iterieren. In dieser Dissertation wird ein modellbasierter Generierungsansatz vorgeschlagen, der kollaborative Szenarios prototypisch auf Grundlage von formalen Verhaltensmodellen für die beteiligten Bedarfsträger darstellt. Durch die Simulation dieses Verhaltens und dessen Animation innerhalb einer webbasierten, domänenspezifischen Visualisierung, können Bedarfsträger diese Modelle erleben und die bisher erfassten Szenarios validieren. Eine derartige interaktive Szenariosimulation wird als modellbasierter virtueller Prototyp bezeichnet. Basierend auf den Interaktionen zwischen Bedarfsträgern und einem virtuellen Prototypen ihrer Szenarios können zudem formale Verhaltensspezifikationen automatisch abgeleitet werden, die wiederum die fragmentierten kollaborativen Szenarios vervollständigen. Dies ermöglicht es den Anforderungsingenieuren, die kollaborativen Szenarios in individuellen Sitzungen mit einzelnen Bedarfsträgern zu erheben und zu validieren – entkoppelt voneinander, da Bedarfsträger webbasiert teilnehmen können und dabei nicht darauf angewiesen sind, dass andere Bedarfsträger ebenfalls in der gleichen Sitzung teilnehmen. Diese Dissertation diskutiert und evaluiert die Machbarkeit, Verständlichkeit sowie die Änderbarkeit der modellbasierten virtuellen Prototypen. Auf die gleiche Art wie physikalische Prototypen wahrgenommen werden, erlaubt es der vorgestellte Ansatz, Verhaltensmodelle für Bedarfsträger erlebbar zu machen und so die Vorteile von Gruppensitzungen mit denen entkoppelter Sitzungen zu verbinden.

One of the factors that seems to influence an individual’s effectiveness in requirements engineering activities is his or her knowledge of the problem being solved, i.e., domain knowledge. While in-depth domain knowledge enables a requirements engineer to understand the problem easier, he or she can fall for tacit assumptions of the domain and might overlook issues that are obvious to domain experts and thus remain unmentioned. The purpose of this thesis is to investigate the impact of domain knowledge on different requirements engineering activities. The main research question this thesis attempts to answer is “How does one form the most effective team, consisting of some mix of domain ignorants and domain awares, for a requirements engineering activity involving knowledge about the domain of the computer-based system whose requirements are being determined by the team?” This thesis presents two controlled experiments and an industrial case study to test a number of hypotheses. The main hypothesis states that a requirements engineering team for a computer-based system in a particular domain, consisting of a mix of requirements analysts that are ignorant of the domain and requirements analysts that are aware of the domain, is more effective at requirement idea generation than a team consisting of only requirements analysts that are aware of the domain. The results of the controlled experiments, although not conclusive, provided some support for the positive effect of the mix on effectiveness of a requirements engineering team. The results also showed a significant effect of other independent variables, especially educational background. The data of the case study corroborated the results of the controlled experiments. The main conclusion that can be drawn from the findings of this thesis is that the presence in a requirements engineering team of a domain ignorant with a computer science or software engineering background improves the effectiveness of the team.

Many of the failures and deficiencies of software projects can be attributed to the lack of effort exerted in addressing requirements in the early planning stages of software development. In multiple stakeholder development environments, requirements will inevitably come into conflict, therefore, it is important to address these conflicts early in software development. The research presented in this thesis surveyed several existing models that resolve requirements conflicts. The goal of the research was to investigate the suitability of these models in identifying, visualizing and solving requirements conflicts. To achieve this goal it was decided to apply these models in a context different than they were originally applied. The context of this research was a process where two stakeholder groups negotiated the requirements of the particular software system. The application of the models was done as a case study. Three models were studied, namely the Utility Curves Model, the Win-Win Model and the \textit{\textbf{i*}} Framework. It was found that each model contributes uniquely to conflict resolution. We have documented strength and limitations for each model and have concluded that these three models should be used together in tandem. A hybrid model was constructed that was composed of the three models. The hybrid model leverages the strengths and addresses the limitations of the three individual models.