The paper describes a general automated method for synthesizing the design of both the topology and parameter values for controllers. The automated method automatically makes decisions concerning the total number of p...
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The paper describes a general automated method for synthesizing the design of both the topology and parameter values for controllers. The automated method automatically makes decisions concerning the total number of processing blocks to be employed in the controller, the type of each block, the topological interconnections between the blocks, the values of all parameters for the blocks, and the existence, if any, of internal feedback between the blocks of the overall controller. Incorporation of time-domain, frequency-domain, and other constraints on the control or state variables (often analytically intractable using conventional methods) can be readily accommodated. The automatic method described in the paper (genetic programming) is applied to a problem of synthesizing the design of a robust controller for a plant with a second-order lag. A textbook PID compensator preceded by a lowpass pre-filter delivers credible performance on this problem. However, the automatically created controller employs a second derivative processing block (in addition to proportional, integrative, and derivative blocks and a pre-filter). It is better than twice as effective as the textbook controller as measured by the integral of the time-weighted absolute error, has only two-thirds of the rise time in response to the reference (command) input, and is 10 times better in terms of suppressing the effects of disturbance at the plant input.
This paper describes how genetic programming can be used to automate the synthesis of the design of both the topology and parameter values for controllers. The method described in this paper automatically makes decisi...
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This paper describes how genetic programming can be used to automate the synthesis of the design of both the topology and parameter values for controllers. The method described in this paper automatically makes decisions concerning the total number of processing blocks to be employed in the controller, the type of each block, the topological interconnections between the blocks, the values of all parameters for the blocks, and the existence, if any, of internal feedback between the blocks of the overall controller. This design process can readily combine optimization of performance (e.g., by a metric such as the integral of the time-weighted error) with time-domain constraints and frequency-domain constraints. Genetic programming is applied to two illustrative problems of controller synthesis: the design of a robust controller for a nonminimal-phase plant and the design of a robust controller for a three-lag plant. The PID compensator of Astrom and Hagglund (1995) for the three-lag plant delivers credible performance. The automatically created controller is better than 7.2 times as effective as the previous controller as measured by the integral of the time-weighted absolute error, has only 50% of the rise time in response to the reference input, has only 35% of the settling time, and is 92.7 dB better in terms of suppressing the effects of disturbance at the plant input.
Current interface descriptions are poor in describing components, because they only provide an external view on a component and they do not lay down how components interact with each other. Suggestions to improve comp...
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In this paper we explain how recursion operators can be used to structure and reason about program semantics within a functional language. In particular, we show how the recursion operator fold can be used to structur...
ISBN:
(纸本)9781581130249
In this paper we explain how recursion operators can be used to structure and reason about program semantics within a functional language. In particular, we show how the recursion operator fold can be used to structure denotational semantics, how the dual recursion operator unfold can be used to structure operational semantics, and how algebraic properties of these operators can be used to reason about program semantics. The techniques are explained with the aid of two main examples, the first concerning arithmetic expressions, and the second concerning Milner's concurrent language CCS. The aim of the paper is to give functional programmers new insights into recursion operators, program semantics, and the relationships between them.
Whereas it is generally acknowledged that code tangling reduces the quality of software and that aspect-oriented programming (AOP) is a means of addressing this problem, there is — as yet — no clear definition or ch...
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A nested datatype, also known as a non-regular datatype, is a parametrised datatype whose declaration involves different instances of the accompanying type parameters. Nested datatypes have been mostly ignored in func...
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The Fudgets system is a toolkit for developing graphical applications in the lazy functional programming language Haskell. In this paper we develop an operational semantics for a subset of this system, inspired by ide...
ISBN:
(纸本)9781581130249
The Fudgets system is a toolkit for developing graphical applications in the lazy functional programming language Haskell. In this paper we develop an operational semantics for a subset of this system, inspired by ideas from concurrency theory. A semantic theory based on bisimulation is defined and shown to be a congruence. We consider two applications of this theory: firstly, some equational rules useful for reasoning about Fudget programs are verified; secondly, we show how the operational semantics can be used to check the correctness of implementations of the Fudgets system.
We introduce a technique to compute several information estimations for Boolean and multivalued functions. Special features of these estimations for completely and incompletely specified logic functions, including sym...
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We introduce a technique to compute several information estimations for Boolean and multivalued functions. Special features of these estimations for completely and incompletely specified logic functions, including symmetric logic functions are investigated. Finally, we give an algorithm for determining various information measures for logical functions based on decision trees.
In the paper we give a straightforward, highly efficient, scalable implementation of common matrix multiplication operations. The algorithms are much simpler than previously published methods, yield better performance...
One of the major difficulties in controlling software development project cost overruns and schedule delays has been developing practical and accurate software cost models. Software development could be modeled as an ...
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One of the major difficulties in controlling software development project cost overruns and schedule delays has been developing practical and accurate software cost models. Software development could be modeled as an economic production process and we therefore propose a theoretical approach to software cost modeling. Specifically, we present the Minimum Software Cost Model (MSCM), derived from economic production theory and systems optimization. The MSCM model is compared with other widely used software cost models, such as COCOMO and SLIM, on the basis of goodness of fit and quality of estimation using software project data sets available in the literature. Judged by both criteria, the MSCM model is comparable to, if not better than, the SLIM, and significantly better than the rest of the models. In addition, the MSCM model provides some insights about the behavior of software development processes and environment, which could be used to formulate guidelines for better software project management polic es and practices.
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