This work presents a tool for automatic generation of controllers' implementationcode from Petri nets models amenable to be deployed into common platforms using widely used high level programming languages, such ...
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ISBN:
(纸本)9781424463916
This work presents a tool for automatic generation of controllers' implementationcode from Petri nets models amenable to be deployed into common platforms using widely used high level programming languages, such as c, c++, and Java. The generated code is linked with platform specific functions, supporting different types of implementation platforms, ranging from low-cost microcontrollers to workstations, and including microcontroller IPs (Intellectual Property) to be embedded into FPGAs (Field Programmable Gate Arrays). The system controller behavior is modeled using IOPT (Input-Output Place-Transition) Petri Nets models, which are represented through PNML (Petri nets Mark-up Language) notation. A tool for automaticcode generation was developed, which achieved this goal in cooperation with other developed tools within a model-based development framework. Application to an automation system composed by a set of distributed controllers is presented.
We consider the problem of computing IEEE floating-point squares by means of integer arithmetic. We show how to exploit the specific properties of squaring in order to design and implement algorithms that have much lo...
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ISBN:
(纸本)9780769543185
We consider the problem of computing IEEE floating-point squares by means of integer arithmetic. We show how to exploit the specific properties of squaring in order to design and implement algorithms that have much lower latency than those for general multiplication, while still guaranteeing correct rounding. Our algorithms are parameterized by the floating-point format, aim at high instruction-level parallelism (ILP) exposure, and cover all rounding modes. We show further that their cimplementation for the binary32 format yields efficient codes for targets like the ST231 VLIW integer processor from STMicroelectronics, with a latency at least 1.75x smaller than that of general multiplication in the same context.
We present FcIRK16, a 16th-order implicit symplectic integrator for long-term high-precision Solar System simulations. Our integrator takes advantage of the near-Keplerian motion of the planets around the Sun by alter...
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We present FcIRK16, a 16th-order implicit symplectic integrator for long-term high-precision Solar System simulations. Our integrator takes advantage of the near-Keplerian motion of the planets around the Sun by alternating Keplerian motions with corrections accounting for the planetary interactions. compared to other symplectic integrators (the Wisdom and Holman map and its higher-order generalizations) that also take advantage of the hierarchical nature of the motion of the planets around the central star, our methods require solving implicit equations at each time-step. We claim that, despite this disadvantage, FcIRK16 is more efficient than explicit symplectic integrators for high-precision simulations thanks to: (i) its high order of precision, (ii) its easy parallelization, and (iii) its efficient mixed-precision implementation which reduces the effect of roundoff errors. In addition, unlike typical explicit symplectic integrators for near-Keplerian problems, FcIRK16 is able to integrate problems with arbitrary perturbations (non-necessarily split as a sum of integrable parts). We present a novel analysis of the effect of close encounters in the leading term of the local discretization errors of our integrator. Based on that analysis, a mechanism to detect and refine integration steps that involve close encounters is incorporated in our code. That mechanism allows FcIRK16 to accurately resolve close encounters of arbitrary bodies. We illustrate our treatment of close encounters with the application of FcIRK16 to a point-mass Newtonian 15-body model of the Solar System (with the Sun, the eight planets, Pluto, and five main asteroids) and a 16-body model treating the Moon as a separate body. We also present some numerical comparisons of FcIRK16 with a state-of-the-art high-order explicit symplectic scheme for 16-body model that demonstrate the superiority of our integrator when very high precision is required.
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