this document presents a MDA-based method for the development of systems dedicated to process control. It proposes to introduce a first sensors/actuators independent model. QoS semantic definitions are then stated;thu...
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ISBN:
(纸本)0769523463
this document presents a MDA-based method for the development of systems dedicated to process control. It proposes to introduce a first sensors/actuators independent model. QoS semantic definitions are then stated;thus, dealing with Quality of Service (QoS) requirements is a way to safely introduce sensors/actuators in the model.
作者：
Bate, IUniv York
Dept Comp Sci York YO10 5DD N Yorkshire England
the development of many systems suffer from unexpected problems during development leading to time and cost penalties. A common situation that leads to problems is when components are integrated and un-anticipated fea...
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ISBN:
(纸本)0769523463
the development of many systems suffer from unexpected problems during development leading to time and cost penalties. A common situation that leads to problems is when components are integrated and un-anticipated features are formed these features are often termed emergent properties. In this paper a compositional approach is adopted where components are parameterised with extra information that can then be used to understand the implications of integration and mapping.
We present an approach to the analysis and optimization of heterogeneous distributed embeddedsystems for hard real-timeapplications. the systems are heterogeneous not only in terms of hardware components, but also i...
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ISBN:
(纸本)0769523463
We present an approach to the analysis and optimization of heterogeneous distributed embeddedsystems for hard real-timeapplications. the systems are heterogeneous not only in terms of hardware components, but also in terms of communication protocols and scheduling policies. When several scheduling policies share a resource, they are organized in a hierarchy. In this paper we address design problems that are characteristic to such hierarchically scheduled systems: assignment of scheduling policies to tasks, mapping of tasks to hardware components, and the scheduling of the activities. We present algorithms for solving these problems. Our heuristics are able to find schedulable implementations under limited resources, achieving an efficient utilization of the system.
In the early phases of embeddedreal-timesystems development, design decisions are made with large consequences on the quality of the resulting product. At the same time, only limited information is available about k...
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ISBN:
(纸本)0769523463
In the early phases of embeddedreal-timesystems development, design decisions are made with large consequences on the quality of the resulting product. At the same time, only limited information is available about key attributes, which makes it difficult to get correct decisions. In this paper, it is studied how to include uncertainty in the information in early phases and to handle the risks involved. Using Monte Carlo simulation, the uncertainties are evaluated based on estimations of basic parameters. the technique is applied to schedulability analysis, and it is shown that the results can be counter-intuitive, and thus that current design practice can lead to higher risk than assumed by the designers.
When real-timeembedded system software needs to be upgraded, it will be more dependable if the new software is sufficiently tested on the actual deployment platform. the challenge is to provide a safeguard for protec...
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ISBN:
(纸本)0769523463
When real-timeembedded system software needs to be upgraded, it will be more dependable if the new software is sufficiently tested on the actual deployment platform. the challenge is to provide a safeguard for protecting the normal operations from faulty upgrades. However, the safeguard must be not only efficient but also able to be added and taken away as needed without shutting down the normal operations. We have developed an architecture based an Simplex Architecture and Process Resurrection and have applied it to the inverted pendulum control system. the measurements show that the overhead is small and justifiable.
this paper presents an implementation of feedback control strategy on distributed static scheduling. the static schedule is created taking into account the average execution times of the tasks. Feedback control algori...
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ISBN:
(纸本)0769523463
this paper presents an implementation of feedback control strategy on distributed static scheduling. the static schedule is created taking into account the average execution times of the tasks. Feedback control algorithm handles the unestimated dynamic behaviors in the system and keeps the performance at a desired level. the approach of feedback control supporting static scheduling yields more flexible scheduling, low scheduling overhead and better resource utilization while preserving the real-time constraints.
Taking dynamic branch prediction into account in WCET determination turns out to be complex, particularly because of the possible interferences between branches. In this paper we argue the case for using static instea...
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ISBN:
(纸本)0769523463
Taking dynamic branch prediction into account in WCET determination turns out to be complex, particularly because of the possible interferences between branches. In this paper we argue the case for using static instead of dynamic branch prediction: the aliasing problem is swept away and, in many cases, the estimated worst-case numbers of branch mispredictions are reduced We propose a method to predict each branch at compile time. Experimental results show how effective this approach can be.
Building real-timeapplications on 802.11 wireless networks is challenging because the medium access protocol is distributed and nodes contend for the channel nondeterministically. So far all attempts at providing rea...
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ISBN:
(纸本)0769523463
Building real-timeapplications on 802.11 wireless networks is challenging because the medium access protocol is distributed and nodes contend for the channel nondeterministically. So far all attempts at providing real-time services in 802.11 require restrictive traffic assumptions such as periodicity. In this paper we describe distributed admission control, a modification to 802.11that, when used with distributed prioritization, provides real-time guarantees for aperiodic packets. We show that barring external errors such as interference on the channel or incorrect priority scheduling this protocol guarantees deadlines will be met.
In recent years, there has been much research on ubiquitous computing, including context aware computingthat is an important field in ubiquitous computing. the primary focus of this paper is on context modeling. We s...
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ISBN:
(纸本)0769523463
In recent years, there has been much research on ubiquitous computing, including context aware computingthat is an important field in ubiquitous computing. the primary focus of this paper is on context modeling. We study the characteristics of context and so the requirements on the modeling. Besides, we also take into account the development requirements of next generation context-aware application. We study the context modeling approaches of some famous existing projects and find that few models meet all these requirements. In this paper, we propose a comprehensive model, which meets these requirements. We implement this model in a middleware called Scudware.
Under limited parallelism, processes competing for a single processor may issue at any time operations on remote co-processors, during which the processor is not idled but granted to other ready processes instead. We ...
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ISBN:
(纸本)0769523463
Under limited parallelism, processes competing for a single processor may issue at any time operations on remote co-processors, during which the processor is not idled but granted to other ready processes instead. We reduce the pessimism in existing Worst-case Response time (WCRT) analysis for such systems by examining temporal patterns of local/remote execution. We extend to multi-CPU variants of the model and offer a WCRT-based feasibility test for Symmetric Multiprocessor (SMP) systems.
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