Spelling suggestions: "subject:"realtime lemsystems"" "subject:"realtime atemsystems""
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A constrained computational model for flexible schedulingMcElhone, Charles Gerard January 1996 (has links)
No description available.
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Computational architecture : a step towards predictable software designVickers, Andrew J. January 1994 (has links)
No description available.
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Correctness and communication in real-time systemsSchneider, Steve A. January 1989 (has links)
No description available.
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Petri nets approach for the analysis of MASCOT interprocess communicationsJiffry, Mustafa Abdulrahman January 2000 (has links)
No description available.
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Scheduling Algorithms for Real-Time SystemsMOHAMMADI, AREZOU 24 April 2009 (has links)
Real-time systems are those whose correctness depends not only on logical results
of computations, but also on the time at which the results are produced. This thesis
provides a formal definition for real-time systems and includes the following original
contributions on real-time scheduling algorithms.
The first topic studied in the thesis is minimizing the total penalty to be paid
in scheduling a set of soft real-time tasks. The problem is NP-hard. We prove the
properties of any optimal scheduling algorithm. We also derive a number of heuristic
algorithms which satisfy the properties obtained. Moreover, we obtain a tight upper
bound for the optimal solution to the problem. Numerical results that compare the
upper bound with the optimal solution and the heuristic algorithms are provided.
In the second part of this thesis, we study the problem of minimizing the number
of processors required for scheduling a set of periodic preemptive independent hard
real-time tasks. We use a partitioning strategy with an EDF scheduling algorithm
on each processor. The problem is NP-hard. We derive lower and upper bounds
for the number of processors required to satisfy the constraints of the problem. We
also compare a number of heuristic algorithms with each other and with the bounds
derived in this research. Numerical results demonstrate that our lower bound is very
tight.
In the third part of the thesis, we study the problem of uplink scheduling in
telecommunication systems with two dimensional resources. Our goal is to maximize
the total value of the packets sent in uplink subframe such that system constraints and
requirements are satisfied. The packets have various QoS requirements and have
either soft or hard deadlines. We take two approaches, namely 0-1 and fractional
approaches, to model the problem. Considering the properties of the application, we
derive globally optimal solutions in polynomial time for the models. We also present
a method to fine-tune the models. Numerical results are provided to compare the
performance of the various optimal algorithms each corresponding to a model. / Thesis (Ph.D, Computing) -- Queen's University, 2009-04-24 08:22:04.238
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Uniting formal and structured methods for the development of reliable softwareShi, Lihua January 1998 (has links)
No description available.
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Integrative framework for discrete systems simulation and monitoringPeytchev, Evtim Todorov January 1999 (has links)
No description available.
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Execution Time Control : A hardware accelerated Ada implementation with novel support for interrupt handlingGregertsen, Kristoffer Nyborg January 2012 (has links)
Execution time control is a technique that allows execution time budgets to be set and overruns to be handled dynamically to prevent deadline misses. This removes the need for the worst-case execution time (WCET) of tasks to be found by offline timing analysis – a problem that can be very hard to solve for modern computer architectures. Execution time control can also increase the processor utilization, as the WCET will often be much higher than the average execution time. This thesis describes how the GNU Ada Compiler and a bare-board Ravenscar run-time environment were ported to the Atmel AVR32 UC3 microcontroller series making the Ada programming language available on this architecture for the first time, and an implementation of Ada execution time control for this system that supports full execution time control for interrupt handling. Usage patterns for this brand new feature are demonstrated in Ada by extending the object-oriented real-time framework with execution time servers for interrupt handling, allowing the system to be protected against unexpected bursts of interrupts that could otherwise result in deadline misses. Separate execution time measurement for interrupt handling also improves the accuracy of measurement for tasks. As a direct result of the work presented in this thesis separate execution time measurement for interrupts will be included in the forthcoming ISO-standard for Ada 2012. While the implementation of execution time control is for the Ada programming language and the UC3 microcontroller series, the design and implementation should be portable to other architectures, and the principles of execution time control for interrupt handling applicable to other programming languages. Low run-time overhead is important for execution time control to be useful for real-time systems. Therefore a hardware Time Management Unit (TMU) was designed to reduce the overhead of execution time control. This design has been implemented for the UC3 and performance tests with the developed run-time environment shows that it gives a significant reduction of overhead. The memory-mapped design of the TMU also allows it to be implemented on other architectures.
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Multiprocessor design for real-time embedded systemsAl-Hasawi, Waleed Isa January 1987 (has links)
No description available.
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Flash Memory Garbage Collection in Hard Real-Time SystemsLai, Chien-An 2011 August 1900 (has links)
Due to advances in capacity, speed, and economics, NAND-based flash memory technology is increasingly integrated into all types of computing systems, ranging from enterprise servers to embedded devices. However, due to its unpredictable up-date behavior and time consuming garbage collection mechanism, NAND-based flash memory is difficult to integrate into hard-real-time embedded systems. In this thesis, I propose a performance model for flash memory garbage collection that can be used in conjunction with a number of different garbage collection strategies. I describe how to model the cost of reactive (lazy) garbage collection and compare it to that of more proactive schemes. I develop formulas to assess the schedulability of hard real- time periodic task sets under simplified memory consumption models. Results show that I prove the proactive schemes achieve the larger maximum schedulable utilization than the traditional garbage collection mechanism for hard real-time systems in flash memory.
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