Contributions published at Requirements Engineering (Martin Glinz)

A bidirectional process for agreeing on product requirements proves effective in overcoming misunderstandings that arise in the traditional handoff of requirements specifications to development teams.

Product success depends on skilled and competent product management. In essence, a product manager decides what functionality and quality a product should offer, to which customers, and when in time, while assuring a winning business case. Software product management is particularly important when the product is envisioned, developed, and deployed in a global environment. Geographical distance and cultural differences need to be addressed when collaborating along the requirements value chain, while robust and effective integration need to be achieved when composing products along the supply chain. The 4th International Workshop on Software Product Management (IWSPM 2010) was held in conjunction with the 18th IEEE International Requirements Engineering Conference (RE'10) in Sydney, Australia. The workshop included a keynote from senior product managers, paper presentations, and discussions on state of knowledge and development of software product management.

The 4th edition of the workshop Models@run.time was held at the 12th International Conference on Model Driven Engineering Languages and Systems (MODELS). The workshop took place in the city of Denver, Colorado, USA, on the 5th of October 2009. The workshop was organised by Nelly Bencomo, Robert France, Gordon Blair, Freddy Muñoz, and Cédric Jeanneret. It was attended by at least 45 people from more than 10 countries. In this summary we present a synopsis of the presentations and discussions that took place during the 4th International Workshop on Models@run.time.

The development of software products and systems generally requires collaboration of many individuals, groups, and organizations that form an ecosystem of interdependent stakeholders. The way the interests and expectations of such stakeholders are communicated is critical for whether they are heard, hence whether the stakeholders are successful in influencing future solutions to meet their needs. This paper proposes a model based on negotiation and network theory for analyzing and designing flow of requirements through a software ecosystem. The approach supports requirements engineering process engineers and managers in taking strategic decisions for resolving communication bottlenecks, increasing overall requirements engineering productivity, and consciously assigning power to stakeholders.

The success of very large product lines systems with globally distributed stakeholders often builds significantly on the implicit knowledge of individuals. Final products are typically built by integrating numerous detailed specifications of subsystems. But how exactly all these parts can and need to be integrated to build valid end products is often left unspecified and to numerous discussions, reviews and the expertise of senior architects and product managers. Building a high-level product line requirements model that explicitly and formally specifies common and variable requirements, their precise integration semantics and the constraints for selecting variable features helps significantly to manage this crucial and often tacit requirements knowledge. Based on an industrial exemplar we motivate and demonstrate such an approach and discuss our early findings regarding knowledge and rationale management in product line requirements engineering.

Today, modelers must rely on their instinct and experience to decide how much detail of a system is worth being modeled. This ad-hoc modeling may result in models that are either too abstract or too detailed for their intended use. We propose to investigate objective measurement of a model’s abstractness and systematic guidance to attain the right level of abstraction. Such a contribution has the potential to improve the quality of models and reduce the amount of time needed for modeling activities.

Software development becomes expensive, when more than three similar products are developed independently, without exploiting the commonality among these products. Requirements Engineering and Software Product Line Engineering help to reduce this costs. An advanced requirements engineering language and tool is needed, which is capable of handling requirements for product lines. ADORA is a requirements engineering tool, which is developed at the University of Zurich, which is capable of modeling product lines. The problem is, that ADORA needs to enable requirement negotiation. This allows the modeler to derive products from the product line. Otherwise much manual, time-intensive work is needed and no real-time requirements negotiations can be performed on that model. The dynamic weaving of single variants allows a quick instantiation of possible application requirements from the product line. Before this thesis was worked out, ADORA could not weave dynamically, which are now handled in a dedicated decision table. Another difficulty is the resulting layout of the weaving. Layout must be human friendly and organized in a proper fashion to support usability of this approach in product derivation with dynamic weaving. For the solution of this problem, we present our approach in this master thesis. First we enable dynamic weaving of single aspects, by deciding on variability decision items in a decision table. Second we improve the layout by automatically providing human friendly graphical layout for the woven models. As a validation we demonstrate our new concepts with two requirements examples: One more detailed specification example and one real-world industrial requirements exemplar. The validation measures aesthetic graphical layout criteria such as less bendings in the edges, less crossing of the edges, smaller difference among node size, avoidance of empty space and mental map preservance.

Software performance engineering provides techniques to analyze and predict the performance (e.g., response time or resource utilization) of software systems to avoid implementations with insufficient performance. These techniques operate on models of software, often at an architectural level, to enable early, design-time predictions for evaluating design alternatives. Current software performance engineering approaches allow the prediction of performance at design time, but often provide cryptic results (e.g., lengths of queues). These prediction results can be hardly mapped back to the software architecture by humans, making it hard to derive the right design decisions. In this paper, we integrate software cartography (a map technique) with software performance engineering to overcome the limited interpretability of raw performance prediction results. Our approach is based on model transformations and a general software visualization approach. It provides an intuitive mapping of prediction results to the software architecture which simplifies design decisions. We successfully evaluated our approach in a quasi experiment involving 41 participants by comparing the correctness of performance-improving design decisions and participants' time effort using our novel approach to an existing software performance visualization.

Nicht erst seit Modellierung zum Modewort geworden ist, ist Modellierung ein wichtiges Thema in der Informatikausbildung. Dieser Beitrag beleuchtet in zwölf Thesen das Warum, Was, Wie viel, Wo, Wann und Wie von Modellierung in der Lehre im Rahmen informatikbezogener Studiengänge. Die Thesen basieren auf der Erfahrung des Verfassers mit einer seit über zehn Jahren gehaltenen Modellierungsvorlesung an der Universität Zürich sowie dem Gedankenaustausch mit anderen Hochschullehrerinnen und -lehrern im Rahmen der GI-Workshopreihe ,,Modellierung“. Zusätzlich liefert eine Befragung von Absolventinnen und Absolventen an der Universität Zürich empirische Evidenz für eine Reihe der Thesen.

Product development organizations often distribute the responsibilities for requirements engineering over several roles. The collaboration of product management, concerned with market needs, and product development, concerned with the technological aspects of a product, is well established. Such shared responsibility provides advantages in the utilization of specific knowledge, skills, and resources. However, the collaboration leads to increased demands on coordination. Novel concepts and models need to be investigated to support such collaborative requirements engineering. In this paper we focus on requirements communication from product management to a development team by proposing and evaluating the model of goal-oriented requirements communication. The model explains how efficiency and effectiveness of requirements communication can be increased and allows the utilization of established requirements engineering knowledge in a new way to address the task of requirements communication.

Product derivation from a product line model is a central activity in product line requirements engineering. A product line framework and/or approach should provide sophisticated visualization and product derivation support, otherwise large product lines become very hard to handle. In this paper we first present how we can benefit from existing single-system visualization techniques in product lines. Then we introduce new visualization aids and concepts that support the analysis of variability and the derivation of products in software product line engineering. We expect that these new visual support mechanisms will significantly ease the work of stakeholders and requirements engineers when negotiating a new product based on a software product line.

The trend towards a global orientation of the companies leads more frequently to a distributed software development. Due to an inappropriate communication requirements get often misunderstood, an inadequate software solution is developed as a consequence. Handshaking represents a structured communication process between stakeholders which uses a new technology called implementation proposal to associate design decisions with the specified requirements. It helps to develop a better understanding for the system to be designed. Thus potential problems can be caught at early stages of the system development. This thesis describes a concept, how Handshaking can be supported by a software solution using the ADORA modelling language. Further it introduces a composition algorithm which makes it possible to dynamically generate implementation proposals straight from the system model. An evaluation of the concept with a prototypical implementation in the form of an Eclipse plug-in yielded promising results and showed that the realization carries further potential.

Customers, product managers, project leaders, architects, engineers, and other stakeholders are negotiating requirements throughout the software lifecycle. Even-though fundamental for understanding requirements engineering, negotiation has not been as thoroughly studied as other facets of this engineering discipline. This paper casts requirements engineering into the landscape of negotiation by describing a framework for selecting tactics and methods for various negotiation constellations that can be encountered in a software organization. The framework opens perspectives that are essential for understanding the behavior of people involved in development projects, for understanding how development teams and stakeholders create mutually satisfactory solutions, and for giving tactical advice to practitioners.

Graphical models are omnipresent in the software engineering field, but most current graphical modeling languages do not scale with the increasing size and complexity of today’s systems. The navigation in the diagrams becomes a major problem especially if different aspects of the system are scattered over multiple, only loosely coupled diagrams. In this paper we present the hierarchical navigation capabilities of the Adora modeling tool. The user of this tool can freely control the level of detail in different parts of the model to reduce the size and complexity of the diagrams being displayed. Our fisheye visualization technique makes it possible to integrate all modeling aspects (structure, data, behavior, etc.) in one coherent model while keeping the size and complexity of the diagrams within reasonable limits.

Quality requirements, i.e. those requirements that pertain to a system's quality attributes, are traditionally regarded to be useful only when they are represented quantitatively so that they can be measured. This article presents a value-oriented approach to specifying quality requirements that deviates from the classic approach. This approach uses a broad range of potential representations that are selected on the basis of risk assessment. Requirements engineers select a quality requirement representation such that they get an optimal balance between mitigating the risk of developing a system that doesn't satisfy the stakeholders' desires and needs on the one hand and the cost of specifying the requirement in the selected representation on the other hand. This issue is part of a special issue on quality requirements.