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Systematic integration of parameterized local search into evolutionary algorithms

Application-specific, parameterized local search algorithms (PLSAs), in which optimization accuracy can be traded off with run time, arise naturally in many optimization contexts. We introduce a novel approach, called simulated heating, for systematically integrating parameterized local search into evolutionary algorithms (EAs). Using the framework of simulated heating, we investigate both static and dynamic strategies for systematically managing the tradeoff between PLSA accuracy and optimization effort. Our goal is to achieve maximum solution quality within a fixed optimization time budget. We show that the simulated heating technique better utilizes the given optimization time resources than standard hybrid methods that employ fixed parameters, and that the technique is less sensitive to these parameter settings. We apply this framework to three different optimization problems, compare our results to the standard hybrid methods, and show quantitatively that careful management of this tradeoff is necessary to achieve the full potential of an EA/PLSA combination.

Combining multiple models of computation for scheduling and allocation

Many applications include a variety of functions from different domains. Therefore, they are best modeled with a combination of different modeling languages. For a sound design process and improved design space utilization, these different input models should be mapped to a common representation. In this paper, we present a common internal representation that integrates the aspects of several models of computation and is targeted to scheduling and allocation. The representation is explained using an example combining a classical process model as used in real-time operating systems (RTOS) with the synchronous data flow model (SDF).

Representation of process mode correlation for scheduling

The specification of embedded systems very often contains a mixture of different models of computation. In particular the data flow and control flow associated to the transformative and reactive domains, respectively are tightly coupled. The paper considers classes of applications that feature communicating processes whose functions depend on a finite set of computation modes. The change between these modes is synchronized by data communication. An approach is presented to model the correlation of process modes and to fully utilize this information for scheduling. A modeling example shows the optimization potential of the new approach.

Adaptive Isolation for Predictability and Security (Dagstuhl Seminar 16441)

This report documents the program and the outcomes of Dagstuhl Seminar 16441 Adaptive Isolation for Predictability and Security. Semiconductor technology is at the verge of integrating hundreds of processor cores on a single device. Indeed, affordable multi-processor system-on-a-chip (MPSoC) technology is becoming available. It is already heavily used for acceleration of applications from domains of graphics, gaming (e.g., GPUs) and high performance computing (e.g., Xeon Phi). The potential of MPSoCs is yet to explode for novel application areas of embedded and cyber-physical systems such as the domains of automotive (e.g., driver assistance systems), industrial automation and avionics where non-functional aspects of program execution must be enforceable. Instead of best-effort and average performance, these real-time applications demand timing predictability and/or security levels specifiable on a per-application basis. Therefore the cross-cutting topics of the seminar were methods for temporal and spatial isolation. These methods were discussed for their capabilities to enforce the above non-functional properties without sacrificing any efficiency or resource utilization. To be able to provide isolation instantaneously, e.g., even for just segments of a program under execution, adaptivity is essential at all hardware- and software layers. Support for adaptivity was the second focal aspect of the seminar. Here, virtualization and new adaptive resource reservation protocols were discussed and analyzed for their capabilities to provide application/job-wise predictable program execution qualities on demand at some costs and overheads. If the overhead can be kept low, there is a chance that adaptive isolation, the title of the seminar, may enable the adoption of MPSoC technology for many new application areas of embedded systems.

Families of Smith form decompositions to simplify multidimensional filter bank design

Imposing structure on the Smith form of an (integer) periodicity matrix N=U/spl Lambda/V leads to efficient m-D DFT implementations. For resampling matrices, i.e. non-singular rational matrices, the authors introduce Smith form decomposition algorithms to generate /spl Lambda/ matrices whose diagonal elements exhibit minimum variance and U matrices with minimum norm. Such structure simplifies non-uniform m-D filter bank design.<<ETX>>

Spezifikation und Modellierung

Dieses Kapitel ist den Aufgaben der Spezifikation und der Modellierung gewidmet. Dabei werden die wichtigsten konzeptionellen Modelle fur Hardware/Software-Systeme vorgestellt.