摘要:

Upper and lower performance bounds are presented for the discrete-time LQ system, designed using a nominal system model but perturbed with bounded uncertain parameters. An example is discussed

ISSN:0020-7721    

DOI:10.1080/00207729408928969

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

System identification and on-line robust control have been developed for a multi-variable system with dead times. For system identification, a modified Astrom and Hagglund' s autotuning method is applied to obtain the transfer function matrix. An accurate transfer function matrix can be obtained using the proposed method. However, if the system has noises, an accurate transfer function matrix may not be obtained even if a relay with hysteresis is used. Modelling error is unavoidable. An on-line robust control based on a stability index is proposed to improve the performance of the control system

ISSN:0020-7721    

DOI:10.1080/00207729408928970

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A deterministic linear controller is designed for a linear time invariant system described by a transfer function model based on pole placement. The knowledge required from the unknown system is the bounds of system uncertainties. It is shown that the resulting controller is robust against both structured and unstructured uncertainties and gives an exponentially stable closed-loop feedback system. The internal model principle is included in the controller design to achieve perfect tracking/ disturbance rejection

ISSN:0020-7721    

DOI:10.1080/00207729408928971

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In an organizational and behavioural context, autonomous systems consist of groups of people tied by the flow of information between a group and its external environment as well as within a group. A mathematical model is used to evaluate such an information flow. The evaluation is performed for different types of external and internal environments. Two major cases are taken into account, i.e. static and dynamic processes describing the external environment. Such issues as the role of correlation and interaction, and the losses caused by incomplete and delayed information are addressed. The results of the model-based evaluation of an information flow in different decision situations are formulated as IF ⃛ AND ⃛ THEN rules that provide some useful knowledge about functioning of autonomous groups. Generation of such knowledge is an important factor in successful implementation of some ideas related to atomized organizations. The concepts included in the model are illustrated with an example providing interpretation and relationship with real situations

ISSN:0020-7721    

DOI:10.1080/00207729408928972

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The Kingdom of Saudi Arabia is playing a key role in the production of petroleum products. Accurate forecasting of the demand/ supply of these products is very essential for proper planning of the refineries of the Kingdom. An overview of the various forecasting methods used for this purpose is presented and a relatively new time series method, dynamic data systems, is applied. Autoregressive moving average models are developed and used for forecasting. A number of statistical tests are applied lo demonstrate that these forecasts are highly accurate and dependable

ISSN:0020-7721    

DOI:10.1080/00207729408928973

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A simple method to investigate robust stability criteria for flexible systems under low-order observer-based controller designs is presented. Stability is defined in the internal sense, instead of the pure input-output (I/ O) sense; that is, stability is defined in terms of the resolvent matrix of the closed-loop system instead of the transfer matrix function. This is superior to the usual robust stability analyses based on I/ O descriptions in the sense that the situation for systems simultaneously subject to spillover ( unmodelled residuals) and parametric perturbations can be treated simply

ISSN:0020-7721    

DOI:10.1080/00207729408928974

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A computational method is developed to evaluate the data loss rate in a communication buffer with finite capacity. Both the producer ( sender) and the consumer (receiver) of this buffer are represented by semi-Markov processes. A data miss occurs when the producer attempts to add a new message to a full buffer. In practice, the capacity of the buffer must be carefully chosen to meet specified maximum data loss rates. The analysis presented can be used to optimize the design of communication systems by determining the appropriate buffer capacity for a required performance level. A semi-Markov model derived from actual measurements of a system program is examined. Useful analytical relations that can be used to compute or validate the parameters of this semi-Markov model are presented

ISSN:0020-7721    

DOI:10.1080/00207729408928975

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A single facility location problem where the distance is measured differently in different regions on the plane is considered. For example, if some demand points are in a city with streets located as horizontal or vertical lines on the map and if other demand points are outside the city where travel in a straight line is possible using, e.g. helicopters, we obtain a mixed distance problem and the current model becomes applicable. We first formulate the problem as a mixed integer non-linear programming problem. Next, we prove the non-convexity of the cost function by showing that it is discontinuous along the line that divides the two regions. Bounds on the value of the cost function are provided. We propose a heuristic, as a modified version of the Weiszfeld algorithm, to solve the problem and compare its performance with a global optimization method. A numerical example and sensitivity analyses are discussed comparing the efficiency of the modified algorithm with the results of the global optimization method

ISSN:0020-7721    

DOI:10.1080/00207729408928976

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A newly developed general expression for the mean time to failure of a parallel system of repairable identical units with warm standby and common-cause failures is presented. Generalized expressions for system reliability and variance of time to failure are also presented along with some special case model formulae

ISSN:0020-7721    

DOI:10.1080/00207729408928977

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In the spirit of Kharitonov, the robust stability of feedback systems under both structured and unstructured perturbations is discussed. Extreme point results are obtained. The stability margin of an interval system family is achieved at pre-specified twelve vertex systems

ISSN:0020-7721    

DOI:10.1080/00207729408928978

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor