This paper focuses on techniques for enhancing the feasibility of using graphic visualization in analyzing the complexities of parallel software. The central drawback to applying such visual techniques is the overhead...
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We consider a class of supervisory control problems that require infinite state supervisors Petri nets with inhibitor arcs (PN's) to model the supervisors. We compare this PN-based approach to supervisory control ...
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We consider a class of supervisory control problems that require infinite state supervisors Petri nets with inhibitor arcs (PN's) to model the supervisors. We compare this PN-based approach to supervisory control to automata-based approaches. The primary advantage of a PN-based supervisory controller is that a PN-based controller provides a finite representation of an infinite state supervisor. For verification, implementation, and testing reasons, a finite PN-based representation of an infinite state supervisor is preferred over an automata-based supervisor. We show that this modeling advantage is accompanied by a decision disadvantage, in that in general the controllability of a language that can be generated by the closed-loop system is undecidable.
With recent improvements in single CPU performance, several issues become more important in multiprocessor design. Two of these are interprocessor communication and locality. In parallel systems with fast CPUs, locali...
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With recent improvements in single CPU performance, several issues become more important in multiprocessor design. Two of these are interprocessor communication and locality. In parallel systems with fast CPUs, locality is vital to performance. However, traditional parallel programming models such as shared memory or message passing do not naturally lead to programs that exhibit locality. In the paper, the Seamless model for interprocessor communication is presented which is based on locality and that allows the programmer to explicitly manipulate a program's locality to optimize performance. Additionally, this model can support latency tolerance with proper hardware support. Extensions to the C programming language that support this model are also presented. Finally, a parallel program utilizing this model is provided to illustrate the paradigm.< >
This paper introduces an algorithm for converting relay ladder logic (RLL) programs for programmable logic controllers (PLCs) into sequential function chart (SFC) programs. Since an SFC (a standardization of Grafcet) ...
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The communication latency problem is presented with special emphasis on RISC (reduced instruction set computer) based multiprocessors. An interprocessor communication model for parallel programs based on locality is p...
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The communication latency problem is presented with special emphasis on RISC (reduced instruction set computer) based multiprocessors. An interprocessor communication model for parallel programs based on locality is presented. This model enables the programmer to manipulate locality at the language level and to take advantage of currently available system hardware to reduce latency. A hardware node architecture for a latency-tolerant RISC-based multiprocessor, called Seamless, that supports this model, is presented. The Seamless architecture includes the addition of a hardware locality manager to each processing element, as well as an integral runtime environment and compiler.< >
Difficulties associated with metric-based design and evaluation of interconnection networks, in the context of massively parallelprocessing systems, are discussed from a relatively philosophical perspective. The issu...
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Two commonly used optical correlation techniques, matched spatial filtering and joint-Fourier transform correlation, are briefly reviewed. A recently proposed real-time joint-Fourier transform correlation is then disc...
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A closed-loop feedback scheme for obtaining a goal microstructure during Hot Isostatic Pressing (HIP'ing) of powders is described. The control scheme relies on previously developed process models describing the pr...
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The authors focus on techniques for enhancing the feasibility of using graphic visualization in analyzing the complexities of parallel software. The central drawback to applying such visual techniques is the overhead ...
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The authors focus on techniques for enhancing the feasibility of using graphic visualization in analyzing the complexities of parallel software. The central drawback to applying such visual techniques is the overhead in developing analysis tools with flexible, customized views. The PARADISE system alleviates some of this design overhead by providing an abstract, object-oriented, visual modeling environment which expedites custom visual tool development. PARADISE is a visual tool which is used to develop other visual tools, or a meta-tool. The authors complement previous work on PARADISE by describing the philosophy behind its design, and how that philosophy leads to a methodology for constructing visual models which characterize parallel systems in general. The emphasis is on the crucial issues in utilizing visualization for parallel software development, and on how PARADISE deals with these issues.< >
In this paper, results on limit cycle oscillations in floating-point implementations of recursive filters are reviewed. Special attention is paid to structures with a single floating-point nonlinearity in the recursiv...
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