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Performance Specifications (performance + specifications)

Distribution by Scientific Domains
Engineering60%

Selected Abstracts

A combined iterative scheme for identification and control redesigns

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2004
Paresh Date
Abstract This work proposes a unified algorithm for identification and control. Frequency domain data of the plant is weighted to satisfy the given performance specifications. A model is then identified from this weighted frequency domain data and a controller is synthesised using the ,, loopshaping design procedure. The cost function used in the identification stage essentially minimizes a tight upper bound on the difference between the achieved and the designed performance in the sense of the ,, loopshaping design paradigm. Given a model, a method is also suggested to re-adjust model and weighting transfer functions to reduce further the worst case chordal distance between the weighted true plant and the model. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Some ideas for QFT research

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 7 2003
Isaac Horowitz
Feedback theory is much less popular now than 5 years ago. However, there is little question that the problem of achieving desired system tolerances from uncertain plants, at minimum cost of feedback, will remain an important, enduring one for many future generations. Although much progress has been made, it is minuscule in comparison with the extent of the problem. The purpose here is to suggest some significant QFT research problems, some tantalizingly on the boundary of the unknown. There have been in the past many suggestions for improvements in feedback synthesis. Most e.g. the Smith Regulator (Int. J. Control 1983;38:977) have been illusory, because they were formulated in a qualitative context, without the disciplines of quantitative uncertainty and performance specifications, degrees of freedom, sensor noise, plant modification, etc. Without such disciplines, it is impossible to properly evaluate competing techniques. The reader is referred to the 1991 Survey paper for some background, Horowitz (Int. J. Control 1991;53(2):255). Copyright © 2003 John Wiley & Sons, Ltd. [source]

The Measure of Performance in Logistics Acquisition

NAVAL ENGINEERS JOURNAL, Issue 4 2000
J. A. Elliott-Brown
ABSTRACT Acquisition reform initiatives changed the way we buy logistics are bought Structured military standards and regulations were replaced with performance specifications to enable determination up front of the best logistics resources for a system as a function of the systems engineering process. The emphasis is on planning the acquisition to know "what, how, when, where, and why" before the contract is written. The need is to incorporate "guidance" in the contract to eliminate future supportability and sus-tainability issues and problems. The goal is to reduce redundancies in deliv-erables, use and enhance what is available, and to be flexible and innovative in meeting logistics requirements. [source]

A Robust Control Real-Time Scheduling Design

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2005
Bing Du
Today's real-time systems need to be operated under tighter performance specifications, and require more and more constraints to be satisfied. These specifications can only be met when system nonlinearities and constraints are explicitly considered. The paper presents a new H,-nonlinear model predictive control scheduling method to regulate the deadline miss ratio and CPU utilization, and to satisfy the performance specifications. It is difficult to accurately model a real-time multimedia system. H, control theory addresses the issue of worst-case controller design for linear plants subjects to unknown additive disturbances and plant uncertainties. Model predictive methodology is extended to H, controllers for nonlinear systems. A scheduling architecture that includes model uncertainty is proposed. We firstly integrate H, robust optimal control and scheduling theory in order to satisfy trade-offs between control performance and computing resource utilization. Performance evaluation results are demonstrated by simulated examples, and earliest-deadline first (EDF) scheduling results are compared. [source]