TITEL

Creating high-quality behavioral designs for software-intensive systems

SPREKER

Gürcan Gülesir, softwarearchitect, Bloomwise

ABSTRACT

In today’s industrial practice, the design of a software-intensive system such as an embedded system is documented often as plain text in a natural language such as English, supplemented with some ad hoc and free form diagrams. Consequently, design documents are often unclear, imprecise, ambiguous, inconsistent, and hard to read and understand. This lack of quality in the design documents causes three major problems:

1. Poor communication: different stakeholders such as customer, supplier, architect, and designer (mis)understand the design in different ways, which causes an excessive number of iterations during the development.

2. Late and costly rework: inspections over the design documents do not reveal various design defects. These defects are discovered often during later phases, for instance testing, where it takes up to hundred times more costly rework to repair such a defect.

3. Poor evolvability: Since design documents are hard to read and understand, it is often too costly to keep them up to date, as the actual design that is implemented in the source code evolves. Consequently, design documents quickly get outdated, in which case engineers loose the overview on the source code. Without such an overview, understanding and maintaining the source code becomes more difficult. Thus, software becomes less evolvable.

In this talk, we present a solution that addresses these three problems, within the scope of the behavioral designs of software-intensive systems. This solution consists of three components:

1. Data-flow diagrams: a visual language for documenting the input-output relation between the actions performed by a software-intensive system.

2. Control-flow diagrams: a visual language for documenting the possible executions of the system, in terms of the actions performed by the system.

3. Vibes (Visual Behaviour Specifications) diagrams: a visual language for documenting temporal or logical constraints on the possible executions of the system.

The benefits of this solution are three fold: 1. a common and precise understanding of behavioral designs by their stake holders, 2. a well-defined consistency relation between multiple diagrams that document a behavioral design, and 3. highly-evolvable documents of behavioral designs.

The solution is applied so far in two pilot projects and three development projects within the Philips Healthcare MRI organization. In addition, the solution is transferred to this organization through four multi-site workshops conducted in Best, the Netherlands, and Cleveland, USA. In these workshops, there were approximately forty participants, consisting of system architects, software architects, software designers, electrical engineers, and technical managers. These participants are currently using the solution in their daily practice.

BIO

Gürcan Güleşir received his PhD degree in software engineering from the University of Twente in 2008. Currently, he is a software architect at Bloomwise, which is a high-tech spin-off company from the University of Twente and Embedded Systems Institute. Since 2004, Güleşir has been working together with system and software architects at ASML and Philips Healthcare to develop both formal and practical methods for documenting and analyzing behavioral requirements and designs of software-intensive embedded systems.

TAAL

Engels