Scientific publications

Cyber-physical systems interact with their physical environment. In this interaction, non-functional aspects, most notably timing, are essential to correct operation. In modern systems, dynamism is introduced in many different ways. The additional complexity threatens timely development and reliable operation.

Usability is a recognized quality of software and complex systems. To investigate relevance of usability methodologies for specialized software tools, this exploratory project surveyed the literature, interviewed three TNO-ESI industry partners on their needs, and scanned the usability knowledge landscape in Dutch universities.

Ensuring safety and security on today’s systems, and systems of systems (SoS), has become a challenge. Systems have become large and complex, they operate in dynamic context and face an ever-changing threatlandscape. Realistically, potential hidden weaknesses and residual flaws must be expected in an SoS, potentially causing undesired emergent behavior.

The use of mobile devices is often limited by the lifetime of their batteries. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to the complexity, work on battery scheduling in literature is limited to either small batteries or to very simple loads.

The Analytical Software Design (ASD) method of the company Verum has been designed to reduce the number of errors in embedded software. However, it does not take performance issues into account, which can also have a major impact on the duration of software development. This paper presents a discrete-event simulator for the performance evaluation of ASD-structured software as well as a compositional numerical analysis method using fixed-point iteration and phase-type distribution fitting.

Synchronous dataflow graphs (SDFGs) are used extensively to model streaming applications. An SDFG can be extended with scheduling decisions, allowing SDFG analysis to obtain properties like throughput or buffer sizes for the scheduled graphs. Analysis times depend strongly on the size of the SDFG. SDFGs can be statically scheduled using static-order schedules.

Performance modeling of embedded systems is used to explore the system-level design-space and compare a wide range of possible solutions with respect to their performance gain. Calibration and validation of the developed performance models help ensure that the performance predictions of these models are accurate.

Wereport about experiences at Philips Healthcare with component-based development supported by formal techniques. The formal Analytical Software Design (ASD) approach of the company Verum has been incorporated into the industrial workflow. The commercial tool ASD:Suite supports both compositional verification and code generation for control components.