@inproceedings {35, title = {Towards Efficient Use of Shared Communication Media in the Timed Model}, booktitle = {Proc. of the 11th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)}, year = {2005}, month = {March}, pages = {342{\textendash}351}, address = {San Francisco, USA}, abstract = {

Embedded computers are increasingly tighter integrated with each other forming distributed embedded systems that interact through a shared communication medium. Often these embedded systems perform services for safety-critical operations that require deterministic computation and predictable communication. However, since these systems are embedded, they must cope with limited resources. One fundamental challenge is to make efficient use of the shared communication medium, especially in the timed model, in which communication tends to cumulate at the end of harmonic periods of tasks. In this article, we present an approach that uses Micro-tasks for splitting computation and communication into several sequentially executed steps to allow for better balanced load on the communication medium in the timed model. We discuss the approach and describe its implementation in OSEK/Works with TTCAN.

}, keywords = {distributed LET, modecs, real-time}, isbn = {0-7695-2302-1}, doi = {10.1109/RTAS.2005.57}, url = {http://dl.acm.org/citation.cfm?id=1049923}, author = {Guido Menkhaus and Fischmeister, Sebastian and Michael Holzmann and Claudiu Farcas} } @inproceedings {27, title = {Task Sequencing for Optimizing the Computation Cycle in a Timed Computation Model}, booktitle = {Proceedings of the International Digital Avionics Systems Conference (DASC)}, year = {2004}, month = {October}, publisher = {IEEE Press}, organization = {IEEE Press}, address = {Salt Lake City, UT, USA}, abstract = {

Recent developments in embedded control systems promote the timed computation model following the principles of logical execution time (LET). Resulting control applications are time deterministic, value deterministic, and their properties may be subject to formal verification against a mathematical model of the control design. However, the timed computation model introduces inefficiencies to computation cycles. As the LET of a real-time control task requires being greater than its worst-case execution time and computed values are always propagated at the end of the LET, actuator updates are unnecessarily delayed. This makes the control cycle less responsive. In this paper, we present an approach that allows the definition of task sequences for a timed computation model implemented by the timing definition language (TDL). Task sequences help minimizing timing delays between sensor readings and actuator updates (e.g., in estimator-based control systems), managing startup and shutdown phases of control systems, and providing mechanisms for error-detection in fault-tolerant systems.

}, keywords = {control systems, distributed LET, modecs, real-time, timed computation model}, isbn = {0-7803-8539-X}, doi = {10.1109/DASC.2004.1390783}, url = {http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1390783}, author = {Fischmeister, Sebastian and Guido Menkhaus} } @inproceedings {26, title = {Time-triggered Communication for Distributed Control Applications in a Timed Computation Model}, booktitle = {23rd International Digital Avionics Systems Conference (DASC)}, year = {2004}, month = {October}, publisher = {IEEE Press}, organization = {IEEE Press}, address = {Salt Lake City, USA}, abstract = {

Distributed real-time control applications consist of sets of tasks that interact with the physical world through sensors and actuators and are executed on a dispersed set of locations that are interconnected by a communication subsystem. Timeliness and safety requirements of the application demand deterministic execution of tasks and predictive communication. Deterministic and predictable systems can be build, and if upper bounds for processing and communication latencies are known and event arrivals have deterministic distributions. In this paper we describe the timing definition language (TDL) system architecture implementing time-triggered computation and time-triggered communication. The TDL system implements the timed computation model and its architecture consists of two parts: TDL-Exe (for time and value deterministic execution of tasks) and TDL-Com (for predictive communication of values). The paper presents TDL-Exe and describes implementation details of TDL-Com.

}, keywords = {distributed LET, modecs, real-time control systems, system architecture, time-triggered communication, timed computation model}, isbn = {0-7803-8539-X}, doi = {10.1109/DASC.2004.1390786}, url = {http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1390786}, author = {Guido Menkhaus and Michael Holzmann and Fischmeister, Sebastian} } @article {25, title = {Middleware fuer eingebettete Systeme (Middleware for Embedded Systems)}, journal = {Noeo}, year = {2003}, keywords = {distributed LET, modecs, real-time}, author = {Wolfgang Pree and Fischmeister, Sebastian and Guido Menkhaus and Gerald Stieglbauer} }