摘要:

AbstractThe dynamic behaviour of piano mechanisms is of interest to many individuals. Pianists can benefit from some understanding of the way in which their movement of the piano keys affects the sound generated; the designers of piano mechanisms seek to achieve specific responses from the piano mechanism. These people need to know the relationships between the forces exerted by the pianist’s fingers and the movement of the piano keys and hammers. Moreover, researchers in such fields as kinesiology and experimental psychology believe that the detailed stud/of piano performance can provide new insights into skilled human motor performance in general.A computer simulation has been developed that can be used to model the dynamic behaviour of a piano mechanism. Given the motion of the piano keys the simulation can be used to find the corresponding motion of the hammers (predicting the time of impact of hammer on string to within one millisecond), and the forces exerted on the keys. This paper describes the theoretical formulation of the model, and the methods used to gather calibration data. The application of the model in a system to monitor piano performance is described, and other possible applications are discussed.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760013

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractCertain networks which are coherent from the viewpoint of the system as a whole appear noncoherent from the viewpoint of the individual terminals served by the system. Describing this noncoherent behavior leads to analytic and computational difficulties. This paper presents a method for modelling the noncoherent problem as a linear combination of coherent subproblems. This approach permits the use of standard analysis techniques for the coherent subproblems and substantially reduces the computational requirements for analysis of such networks.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760014

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractSolid fuels as bark and waste-wood are typically burned on grates. To ensure good stability and load following properties for grate boilers both the drying and combustion processes must be well controlled. This presumes good instrumentation for the grate, special measurements and control systems for combustion power and good knowledge of the process behaviour.This paper presents the principles for modelling the grate boiler. Simulation model is developed on the basis of process experiments. The methods and devices for modelling and simulation are also handled. The paper further proposes a control system for the supply and combustion parts of a grate boiler.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760015

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA mathematical model is presented for the computation of two-dimensional, turbulent and recirculating flows over bluff bodies, which are separated from nearby walls with a relatively small clearance. The model comprises elliptic, two-dimensional differential-equations expressing mass conservation, momentum balance and the transport of two turbulence properties.The model is applied to predict different flows and the computed flow patterns are displayed and investigated. Comparison is made against experimental measurements available for these flows, and good agreement is generally revealed.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760016

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractAccurate system modelling is becoming more and more important in the analysis and synthesis of hydraulic systems. Pumps with constant-pressure regulators are becoming increasingly common in hydraulic systems. Although these pumps often play an important part in the dynamic behaviour of a particular system, their dynamic properties are often unknown.In this paper it is shown that a simple two-parameter linear model is usually sufficient to describe the dynamic behaviour of a pump with a constant-pressure regulator, provided the disturbances are not too large. For a particular pump it is shown how these parameters are related to the system variables–pressure and flow. These two parameters are the pump inductance (inertance) and a characteristic break frequency for the pump.Due to the many non-linearities of the regulator, large disturbances will require simulation of the non-linear equations. The pump is supposed to be connected to a system which can be described with concentrated parameters, and the response to various disturbances is investigated. The simulation program used, HOPSAN, has the advantage of including a routine for FFT-analysis, which provides a possibility of determining open-loop and closed-loop response of the control system directly from a simulated response of the system with step input.The results of linear models and simulation of nonlinear models are compared with experiments. The agreement is good.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760017

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe measurements of ground resistance obtained by the fall-of-potential method may be rough when the auxiliary current electrode cannot be placed far from the electrode to be tested. In this case, in order to measure the ground resistance with a better precision, the potential electrode must be placed in a particular position. The positions suggested by IEEE Standards 81-1983 are based on the simplifying ?ohypotheses which are not always acceptable. This paper presents a new computing procedure which simulates the fall-of-potential method and eliminates the assumption of point source. In this way the possibility of determining the correct position of the potential electrode is given also when the electrode under test penetrates in the second layer of the soil model. Graphs of the potential electrode positions for driven-rods of different dimensions are supplied.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760018

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractWhen sizing reservoirs with high regulation levels,by using syntherically generated inflows, the latters’Hurst coefficient h,expressing their percistence, must be preserved by properly selecting the flow-generating model. The influence on sizing of using the FFGN (Fast Fractional Gaussian Noise) model, which allows preservation of h, instead of the widely used Thomas-Fiering model, which fails to preserve h, is shown to be significant. The former results to a more conservative and reliable design than the latter (or any other Markovian) model. The analyzed data refer to the Kremasta reservoir on the Acneloos river in Western Greece with 27-year long Inflow series, which is supposed to be fully regulated for an operational horizon of 50-years.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760019

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractRobust, i.e. structurally stable modelling of the motion of articulated vehicles is important in order to get all qualitatively possible ways of behavior. For the example of a tractor- semitrailer vehicle it is shown, that in a two parameter family (driving speed V and the loading condition expressed by the location d of the masscenter of the trailer) only three classes of qualitatively different ways of behavior are possible. These cases are analysed by perturbing them in the most general way possible by means of imperfection parameters, to obtain a robust model. The mathematical methods are supplied by Bifurcation Theory.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760020

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractA knowledge based model of commodity trading is developed based on the expertise of one commodity trader. The model analyzes the Soybean and Live Beef Cattle markets, and suggests feasible actions for the trader. Some background for expertise and knowledge based smodeling is presented, as well as the model structure, its heuristics, and output. Finally the strengths and limitations of the model in its current development stage are discussed, along with future development strategies.

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760021

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0228-6203    

DOI:10.1080/02286203.1987.11760022

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor