Publications

Synchronous dataflow graphs (SDFGs) are widely used to represent digital signal processing algorithms and streaming media applications. This paper presents several methods for binding and scheduling SDFGs on a multiprocessor platform. Exploring the state space generated by a self-timed execution (STE) of an SDFG, we present an exact method for static rate-optimal scheduling of SDFGs via implicit retiming and unfolding.

Domain Specific Languages (DSLs) provide a lightweight approach to incorporate formal techniques into the industrial workflow. From DSL instances, formal models and other artefacts can be generated, such as simulation models and code. Having a single source for all artefacts improves maintenance and offers a high return on investment of the initial modelling effort.

We evaluate the effect of applying the commercial formal technique Analytical Software Design (ASD) to an industrial project. In ASD, interfaces and software designs are modelled using a formal tabular notation. The ASD tool set supports formal checks of these models, such as deadlock freedom and interface compliance.

Exploration of design alternatives and estimation of their key performance metrics such as latency and energy consumption is essential for making the proper design decisions in the early phases of system development. Often, high-level models of the dynamic behavior of the system are used for the analysis of design alternatives.

The high-tech industry produces complex devices in which software plays an important role. Since these devices have been developed for many decades, an increasing part of the software can be classified as legacy which is difficult to maintain and to extend. To improve the maintainability of legacy components, domain specific languages (DSLs) provide promising perspectives.

Wireless in-vehicle networks are considered as a flexible and cost-efficient solution for the new generation of cars. One of the candidate wireless technologies for these wireless sensor networks is the IEEE 802.15.4 standard which operates in the 2.4 GHz ISM band. This is while the number of wireless devices that operate in this band is ever increasing.

The need for authentic and effective portrayal of the spatiotemporally changing quality of wireless links has gained wide attention especially over the last decade. Software-based link quality estimators (LQE) classify links with help of packet reception ratio (PRR), required number of packet transmissions (RNP) and scoring/grading schemes that again utilize PRR, RNP or retransmission based heuristics.

Self re-entrant flowshops consist of machines which process jobs several times. They are found in applications like TFT-LCD assembly, LED manufacturing and industrial printing. The structure of a self re-entrant flowshop influences its performance. To get better performance while reducing costs a fast performance estimation method can be used to explore the trade-offs between the structure and the performance during the design process.

Today’s embedded and cyber-physical systems are getting more connected and complex. One main challenge during development is the often loose coupling between engineering tools, which could lead to inconsistencies and errors due to the manual transfer and duplication of data. Open formats and specifications raise expectations for seamlessly integrated tool chains for systems engineering combining best-of-breed technologies and tools of different tool vendors.

The problem of online face tracking from unconstrained videos is still unresolved. Challenges range from coping with severe online appearance variations to coping with occlusion. We propose RFTD (Robust Face Tracking-by-Detection), a system which combines tracking and detection into a single framework to robustly track a face from unconstrained videos.