The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
P. Altenbernd - One of the best experts on this subject based on the ideXlab platform.
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From high-level specifications down to software implementations of parallel embedded Real-Time Systems
Proceedings Design Automation and Test in Europe Conference and Exhibition 2000 (Cat. No. PR00537), 2000Co-Authors: C. Rust, P. Altenbernd, F. Stappert, J. TackenAbstract:In this paper we describe a methodology and accompanying tool support for the development of parallel and distributed embedded Real-Time System software. The presented approach comprises the complete design flow from the modeling of a distributed controller System by means of a high-level graphical language down to the synthesis of executable code for a given target Hardware, whereby the implementation is verified to meet Hard Real-Time constraints. The methodology is mainly based upon the tools SEA (System engineering and animation) and CHaRy (the C-LAB Hard Real-Time System).
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CHaRy: the C-LAB Hard Real-Time System to support mechatronical design
Proceedings International Conference and Workshop on Engineering of Computer-Based Systems, 1997Co-Authors: P. AltenberndAbstract:CHaRy is a software System to support the synthesis of periodic controller applications, where Hard Real-Time conditions must be guaranteed for software tasks. Due to complexity reasons, CHaRy decomposes the overall problem of implementing periodic controllers on parallel embedded computers to sub-problem partitioning, timing analysis, allocation and schedulability analysis. This rigorous decomposition is relatively new for Hard Real-Time software. Since CHaRy takes into account both the embedded controller applications as well as the encompassing System, the engineering of computer based Systems (ECBS) is supported. Since all these sub-problems are still of huge complexity, CHaRy provides efficient heuristics for all these subjects. Hence CHaRy supports the mapping of controller models (implemented by C code) to a number of tasks (partitioning), the extraction of their computation times (timing analysis), and their assignment to a processor network (allocation), so that all Hard Real-Time conditions are guaranteed (schedulability analysis). The paper provides an overview of the System, supported by many examples.
C. Lanier - One of the best experts on this subject based on the ideXlab platform.
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Early experience with POSIX 1003.4 and POSIX 1003.4 A
[1991] Proceedings Twelfth Real-Time Systems Symposium, 1991Co-Authors: B.o. Gallmeister, C. LanierAbstract:Two proposed IEEE standards for Real-Time operating Systems support, POSIX.4 and POSIX.4a, are proceeding towards IEEE approval and will eventually become international standards. The authors provide a brief overview of the facilities of POSIX.4 and POSIX.4a. They concentrate on a few of the critical features that POSIX.4 and POSIX.4a provide and describe the POSIX.4 scheduling interface. The POSIX.4a support for multiple threads of control is also described. The features found in POSIX.4 and POSIX.4a for synchronization of multiple threads, are discussed, and the POSIX.4 interprocess communication facility is presented. The performance numbers are given to allow comparisons of the facilities of traditional Unix Systems, the facilities of a representative Hard Real-Time System (LynxOS), and the facilities of POSIX.4 and POSIX.4a.
William Pugh - One of the best experts on this subject based on the ideXlab platform.
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A partial evaluator for the Maruti Hard Real-Time System
Real-Time Systems, 1993Co-Authors: Vivek Nirkhe, William PughAbstract:The use of high-level programming constructs (such as recursion, loops, and dynamic data structures) makes it difficult to estimate at compile-time the execution time and resource requirements of a program. We contend that partial evaluation provides a solution to this problem. Given a Real-Time program employing high level language constructs, partial evaluation uses information about the execution environment to create a specialized program tailored for that particular environment. Specialized programs can be better analyzed to estimate accurately the execution time and resource requirements. Our techniques offer substantially greater power and flexibility to the programmer than previous estimation techniques for Real-Time Systems. This paper describes the application of partial evaluation to programming languages for Hard-Real-Time Systems, gives examples of programs handled by our techniques, discusses how the System appears from a user's perspective, provides an overview of the partial evaluation techniques employed using examples and describes some limitations of our techniques and possible solutions.
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RTSS - A partial evaluator for the Maruti Hard Real-Time System
[1991] Proceedings Twelfth Real-Time Systems Symposium, 1991Co-Authors: Vivek Nirkhe, William PughAbstract:The use of high-level programming constructs makes it difficult to estimate at compile-time the execution time and resource requirements of a program. The authors contend that partial evaluation provides a solution to this problem. They describe the application of partial evaluation to programming languages for Hard-Real-Time Systems and give examples of programs handled by the techniques. They discuss how the System appears from a user's perspective, provide a brief overview of the partial evaluation techniques used, and describe some limitations of the techniques and possible solutions. >
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A partial evaluator for the Maruti Hard Real-Time System
[1991] Proceedings Twelfth Real-Time Systems Symposium, 1991Co-Authors: Vivek Nirkhe, William PughAbstract:The use of high-level programming constructs makes it difficult to estimate at compile-time the execution time and resource requirements of a program. The authors contend that partial evaluation provides a solution to this problem. They describe the application of partial evaluation to programming languages for Hard-Real-Time Systems and give examples of programs handled by the techniques. They discuss how the System appears from a user's perspective, provide a brief overview of the partial evaluation techniques used, and describe some limitations of the techniques and possible solutions.
Habibah Ismail - One of the best experts on this subject based on the ideXlab platform.
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A schedulability analysis for weakly Hard Real-Time tasks in partitioning scheduling on multiprocessor Systems
2014 8th. Malaysian Software Engineering Conference (MySEC), 2014Co-Authors: Habibah Ismail, Dayang N. A. JawawiAbstract:The importance of missing a deadline is one of the classifications of a Real-Time tasks or Systems. A weakly Hard Real-Time System is a new generation for a Real-Time System in which some degree of missed or losses deadlines are tolerated occasionally but the missing of deadlines has to be stated precisely. For a traditional Real-Time System, timing requirements in Hard Real-Time are very restrictive, must meet all the tasks deadlines. Meanwhile, in soft Real-Time timing requirements, the requirements are too relaxed because there are no guarantees can be given for the deadline, whether it is met or missed. As a Systems demand complex and significantly increased functionality, multiprocessor scheduling has been given attention and taken into consideration. In fact, within the multiprocessor, the predictability problems seem even Harder. Thus, in order to deal with the problem, the partitioned multiprocessor scheduling techniques with solutions for the bin-packing problem, named R-BOUND-MP-NFRNS (R-BOUND-MP with next-fit-ring noscaling) combining with the exact analysis, called hyperperiod analysis and deadline models; weakly Hard constraints and μ-pattern are present to provide weakly Hard Real-Time guarantees under static priority scheduling algorithm. We prove that the proposed approach provides predictable weakly Hard Real-Time tasks through validation and simulation results.
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A scheduling analysis framework for predicting the weakly Hard Real-Time Systems
2013Co-Authors: Habibah IsmailAbstract:For Real-Time Systems, Hard Real-Time and soft Real-Time Systems are based on “miss restriction” and “miss tolerance”, respectively. However, a weakly Hard Real-Time System integrates both these requirements. The problem with these Systems is the limitation of the scheduling analysis method which only uses the traditional scheduling approach. Besides that, the current framework has problems with the complexity and predictability of the Systems. This study proposed a scheduling analysis framework based on the suitability of scheduling algorithms, weakly Hard Real-Time modelling and the combination of the deterministic and probabilistic schedulability analyses for predicting the weakly Hard Real-Time tasks. Initially, the best fitting specification of a weakly Hard Real-Time System was integrated into the proposed framework and tested in the Modeling and Analysis of Real-Time Embedded Systems (MARTE) profile. The profile was enhanced because the current MARTE timing constraint restricted to the Hard and soft real time timing requirement, thus some modifications were made to model the weakly Hard Real-Time requirements. For complex Systems, rather than only using scheduling algorithms to schedule the tasks, the algorithms were used with Unified Modeling Language (UML) modelling. Sequence diagram complexity factor metrics were used to measure the behavioural complexity. The proposed combination approach was applied on case studies and then evaluated with reference to the existing approaches. The results of the evaluations showed that the proposed framework is more predictable compared to the other frameworks and has addressed the problem posed in this research. In conclusion, the proposed scheduling analysis framework provides a less complex design through the behavioural complexity measurements, as well as increases the predictability of the Systems.
B.o. Gallmeister - One of the best experts on this subject based on the ideXlab platform.
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Early experience with POSIX 1003.4 and POSIX 1003.4 A
[1991] Proceedings Twelfth Real-Time Systems Symposium, 1991Co-Authors: B.o. Gallmeister, C. LanierAbstract:Two proposed IEEE standards for Real-Time operating Systems support, POSIX.4 and POSIX.4a, are proceeding towards IEEE approval and will eventually become international standards. The authors provide a brief overview of the facilities of POSIX.4 and POSIX.4a. They concentrate on a few of the critical features that POSIX.4 and POSIX.4a provide and describe the POSIX.4 scheduling interface. The POSIX.4a support for multiple threads of control is also described. The features found in POSIX.4 and POSIX.4a for synchronization of multiple threads, are discussed, and the POSIX.4 interprocess communication facility is presented. The performance numbers are given to allow comparisons of the facilities of traditional Unix Systems, the facilities of a representative Hard Real-Time System (LynxOS), and the facilities of POSIX.4 and POSIX.4a.
