Probing signals for output constrained processes

Probing input signal design for enhancing the identification of process parameters is developed for scalar input-output processes with output constraints. The sensitivity approach is used and the problem is formulated as an open loop optimal control problem. The solution is via integer programming. Numerical examples illustrate the results.     

A model reference adaptive technique of identification for discrete systems

A rapidly convergent algorithm based on a model reference adaptive technique for the identification of the unknown parameters of a noise free discrete dynamical system is presented. This algorithm is based on a geometric interpretation of the Kudva-Narendra scheme. The algorithm does not require any a priori information about the system. An example is included to demonstrate the strength of the algorithm.     

An output error identification interpretation of model reference adaptive control

The task of discrete model reference adaptive control is manipulated into an output error identification problem. Strictly causal output error identifiers recently developed as adaptive recursive filters are therefore proposed for unique provision of a model reference adaptive control algorithm relying only on input-output data.     

基于系统辨识的模型参考自适应控制

介绍了荷兰Twente大学控制工程系研发的先进控制实验平台的基本组成、功能和基于机电一体化设计软件20-sim。以先进控制演示仪为研究对象,在20-sim环境下建立了系统的图标化数学模型,并从理论上对模型作了降阶分析。根据系统辨识的模型参考自适应控制（MRAC）原理,编制了模型参考自适应和Lyapunov求解模块。采用线性二次型调节器为控制模块,构成了完整的先进控制演示仪的MRAC控制系统。该系统仿真结果显示所建立的模型针对性强,可用于各种先进控制策略的仿真研究。     

Optimal levels of perturbation signals for nonlinear system identification

A method is developed for determining the optimal levels of multilevel perturbation signals for nonlinear system identification, using condition numbers of submatrices of the Vandermonde matrix of the input levels vector. It is applicable when the perturbation signal is applied directly to a static nonlinearity. Optimal levels can be obtained for every order of nonlinearity less than the number of levels, and in most cases the optimal levels are not all distinct. The results show that there is no advantage in using signals with more than the minimum necessary number of distinct levels, although it may be advantageous if some of the distinct levels appear more than once in the input levels vector. The optimal levels are unchanged by multiple occurrences of every level of the input levels vector during a measurement period, and they are shown to be the global optima for pseudorandom perturbation signals derived from maximum-length sequences, in which the occurrence of the zero level is one less than the occurrences of the other levels during a period.     

A model reference approach to safe controller changes in iterative identification and control

A controller change from a current controller which stabilises the plant to a new controller, designed on the basis of an approximate model of the plant and with guaranteed bounds on the stability properties of the true closed loop, is called a safe controller change. In this paper, we present a model reference approach to the determination of safe controller changes on the basis of approximate closed loop models of the plant and robust stability results in the ν-gap.     

An Addendum to "Unbiased recursive identification using model reference adaptive techniques"

It is shown in this correspondence that for recursive identifiers using "parallel" model reference adaptive systems the sufficient stability conditions which can be established depend on the rate of decrease of the adaptation gains. This result generalizes and corrects the result given in [I].     

MMSE channel estimation for two-port demodulation reference signals in new radio

Dear editor, Orthogonal frequency division multiplexing (OFDM) has been adopted in new radio (NR)[1],and multiple-port de-modulation reference signal (DMRS) has...     

Nonparametric algorithm for input signals identification in static distributed-parameter systems

In this correspondence, a nonparametric algorithm for identification of input signals in linear, static distributed-parameter systems is proposed and investigated. Integral mean-square convergence of the algorithm is proved for an infinite number of point measurements of the system state. The algorithm is a generalized version of the one recently proposed by Rutkowski [10] for nonparametric function fitting, and in a common area, the presented results are complementary.     

Simple method for model reference adaptive control

A simple method is presented for combined signal synthesis and parameter adaptation within the framework of model reference adaptive control theory. The results are obtained using a simple derivation based on an improved Lyapunov function.     

Refining visualization reference model for context information

Context-awareness can be used to decrease the need for interaction with a mobile device. This is increasingly important since the functionality of mobile devices and personal digital assistants gets more and more complex while the input and output capabilities remain restricted. An important aspect of context-awareness is to present the current context to the user. We propose a model for visualizing contextual information on the mobile terminal screen. The model is a refinement of a well-known visualization reference model; it takes into account the specific characteristics of mobile use and context information. We present the design of the model in detail, and discuss its applicability for a variety of contexts and tasks by providing a full-fledged use case.     

A reference model for object data management

This article describes a proposed reference model that provides a conceptual framework intended to facilitate the development of more concrete standards in the area of object-oriented databases. This reference model is being developed by the Object-Oriented Databases Task Group (OODBTG). OODBTG is a subcommittee under the ANSI ASC/X3 body, and is charted to develop a reference model and recommendations which will guide future ANSI efforts to develop more concrete standards in the area of object-oriented software technology. Reprinted here is the May 1990 working draft of the reference model, as distributed at that time for public review and comment.     

A reference model for requirements and specifications

The authors define a reference model for applying formal methods to the development of user requirements and their reduction to a behavioral system specification. The approach focuses on the shared phenomena that define the interface between the system and the environment     

Frequency domain system identification using arbitrary signals

It is the common conviction that frequency domain system identification suffers from the drawback that it cannot handle arbitrary signals without introducing systematic errors. This paper shows that it is possible to deal with nonperiodic signals without any approximation and under the same assumptions as in the time domain, by estimating simultaneously some initial conditions and the system model parameters     

Constrained multisine input signals for plant-friendly identification of chemical process systems

This paper considers the use of constrained minimum crest factor multisine signals as inputs for plant-friendly identification testing of chemical process systems. The methodology presented here effectively integrates operating restrictions, information-theoretic requirements, and state-of-the-art optimization techniques to design minimum crest factor multisine signals meeting important user-specified time and frequency domain properties. A series of optimization problem formulations relevant to problems in linear, nonlinear, and multivariable system identification are presented; these culminate with their application to the modeling of the Weischedel–McAvoy high-purity distillation column problem, a demanding nonlinear and highly interactive system. The effectiveness of these signals for modeling for control purposes and the ability to incorporate a priori nonlinear models in the signal design procedure are demonstrated in this distillation system case study.     

Instrument identification and pitch estimation in multi-timbre polyphonic musical signals based on probabilistic mixture model decomposition

In this paper, we propose a method based on probabilistic mixture model decomposition that can simultaneously identify musical instrument types, estimate pitches and assign each pitch to its source instrument in monaural polyphonic audio containing multiple sources. In the proposed system, the probability density function (PDF) of the observed mixture note is treated as a weighted sum approximation of all possible note models. These note models, covering 14 instruments and all their possible pitches, describe their dynamic frequency envelopes in terms of probability. The weight coefficients, indicating the probabilities of the existence of pitches of a certain type of instrument, are estimated using the Expectation-Maximization (EM) algorithm. The weight coefficients are used to detect the types of source instruments and the pitches. The results of experiments involving 14 instruments within a designated pitch range F3–F6 (37 pitches) demonstrate a good discrimination capability, especially in instrument identification and instrument-pitch identification. For the entire system including the note onset detection tool, using quartet polyphonic recordings, the average F-measure values of instrument-pitch identification, instrument identification and pitch estimation were 55.4, 62.5 and 86 % respectively.     

一种基于改进反电动势的模型参考自适应转速辨识方法

构建了感应电动机的数学模型;在分析基于无功功率的模型参考自适应的稳定性的基础上,提出一种基于改进反电动势的模型参考自适应转速辨识的新方法,即重新构造模型参考自适应转速辨识的误差信号,该信号包括反电动势的误差矢量与转子磁链矢量的叉乘和点乘,通过误差信号辨识出电动机的转子转速。试验结果表明,该方法克服了基于反电动势的模型参考自适应在停车制动及发电状态下的不稳定性问题。     

A parametrization for model reference adaptive pole placement

A new parametrization for a linear system is presented. This parametrization is the basis for two approaches to design an adaptive controller for pole placement. One approach is based on parameter estimation and requires sufficient excitation, while the other, the model reference adaptive pole placement, uses a reference model and an augmented error. It is shown that the two distinct approaches result in identical error terms.     

Toward a business model reference for interoperability services

The importance of interoperability for businesses is undoubted. After an evolution from electronic data interchange to interoperability in electronic business and enterprise interoperability both the scientific and the practitioners’ community are today discussing the notion of interoperability service utilities. Furthermore, researchers are studying decentralized and distributed interoperability approaches such as peer-to-peer networks, for example. However, a comprehensive investigation of business models for such decentralized approaches to interoperability is still missing. Drawing from recent literature on business modeling on the one hand and interoperability research on the other hand this paper designs a business model reference for interoperability services. The business model reference assumes interoperability information as an economic good and is applied in two case studies and evaluated from multiple perspectives. The paper contributes to the scientific body of knowledge as it proposes a novel design artifact which lays the foundation for a number of future research opportunities.