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The systems under consideration are governed by a set of first-order linear partial differential hyperbolic equations together with boundary conditions. The Lyapunov method is used to verify the stability of the initial-boundary value problem. Necessary and sufficient conditions for stability are obtained under the assumption that the matrix coefficients in the differential equations and in the boundary...
An implementation of a CMOS current-mode instantaneous companding integrator in strong-inversion is presented. The main advantage of the proposed circuit is its simplicity. Moreover, the frequency response of the integrator can be easily compensated. The operation of the circuit has been confirmed through simulations, conducted for [formula] n-well CMOS process.
The analysis of possibilities of self-replication of informatic programs and self-replication of the objects with their internal software has been derived. Based on nanotechnologies [2] and nanosystems [3] of informatics with the self-replication properties, the two conceptions -- self-replication of a program through generation of its own copy and passing over to copy activation; double recording...
It was shown in this paper that classical approach to the assessment of systems condition evolution can be much improved by special processing of observed symptoms of condition. When we have a large symptom data base, we can apply singular value decomposition (SVD) as the newest data mining procedure, to obtain a symptom and condition evolution model. By using SVD it is possible to have two additional...
The capabilities of computer analysis in optimisation and diagnostics of technical objects such as power industry turbosystems are indicated in the work. Based on the developed dynamical models of such objects an analysis of the influence of selected design parameters on the statistic and dynamic properties of the object has been conducted. Presented examples refer to real objects operating in Poland...
Diagnostic model of an object describes the relations between observed symptoms and their causes, i.e. the technical states of the object. Direct specification of such models is (quite) impossible due to the complex nature of these relations. This paper aims to inform the reader about the general idea of inverse diagnostic models. A special attention has been drawn to the application of known cause-effect...
The paper deals with a comprehensive methodology concerning knowledge acquisition on machinery for the purpose of expert systems suitable for aiding of diagnostic inference. The methodology includes selected methods of diagnostic knowledge representation, methods of knowledge acquisition from domain experts and from previously classified examples, methods of assessment of previously acquired knowledge...
Properties of man-machine systems can be described with the rate/effect-generation models. The paper is an effort to formulate and classify such models and to improve their rate/effect-generation characteristics owing to supervisory systems employed. It has been shown that applying the supervisory-and-therapeutic systems enables the range of performed utilitarian tasks to be extended.
The vibro-acoustics has found itself a permanent position among technical sciences. The basic tasks and problems formulated several years ago are successively supplemented. It might be clearly stated that this field of science will be further developing in the XXIst century. Regardless of many achievements several vibro-acoustic problems have not been yet solved and therefore investigations concerning...
In this work problems of condition forecasting, in this specially of marking of following diagnosis term in dynamic strategy of mechanical vehicles exploitation have been represented. Problem of marking optimum - prognoses of technical condition of mechanical vehicle are examined, collection of solutions admissible and collection of criterions partial criterial function of optimum assignment are qualified...
The neural model-based Fault Detection and Isolation (FDI) system for dynamic non-linear processes is considered. The emphasis is placed upon the use of Artificial Neural Networks (ANN's) for residual generation. The proposed network is constructed with the Dynamic Neuron Model (DNM) which contains local memory. Similar to server based schemes, a network is applied to build the nominal and fault models...
The paper presents several aspects of steam turbine diagnostics and stress is put mainly on methods that employ data obtained from experiments. Vibroacoustic methods, based on suitable models, provide much information on turbine technical condition, in addition to being relatively simple and non-intrusive. In many cases, accuracy of the diagnosis can be substantially improved if other symptoms, related...
The work concerns diagnosis of the origins and development of early stages of defects based on information found in the vibroacoustic signal. At the beginning the necessity of selection of diagnostic parameters dependent upon the amount of dissipated energy and related defect development is proven. Assuming that the basic role in transmission of such diagnostic information is played by the phenomena...
Problems concerning the modelling of the vibro-acoustic emission of machines have been presented in the paper. Several algorithms useful in modelling of the acoustic field around machines have also been shown. Results of acoustic pressure and sound intensity measurements around industrial sound sources were the bases of model formations. The sound field modelling of the actual sound source by the...
The method of fault isolation in large scale industrial processes is considered. The paper introduces description of the diagnosed object in form of an information system. The proposed algorithm takes into account the dynamics of the symptoms. The result of such approach is augmentation of fault discernment and speed of fault isolation.
The paper presents a new methodology of modal model identification. The modal experiment consists in measurement of the tested system response to operating loads during its normal operation. The measured acceleration signals are used for estimation of cross- and auto-correlation functions for all measurement points. Then the Least Squares Complex Exponential algorithm is applied for modal model identification...
An application of a lattice adaptive neurofuzzy system to circuit performance modelling is presented in the paper. The investigated system makes use of the B-spline membership functions and a structure of the system is determined by means of a genetic algorithm. The presented approach possesses good modelling capabilities and, contrary to non-lattice neurofuzzy approaches, can explore structural dependencies...
A new dynamic assignment problem for linear standard time-invariant systems is formulated and solved. Necessary and sufficient conditions are established for the existence of the state-output derivative feedbacks such that the closed-loop characteristic polynomial is equal to the desired one of the degree less than the system order. A procedure is derived for computation of gain matrices of the feedback.
The paper presents two theorems on immunization in the continuous context when a liability consists of a single outflow at a known future date. It is assumed in Theorem 1 that interest rates h(O, t) shift to their new values h * (O, t) = h(O, t) + f()..)a(t) where ).. is a random parameter "chosen" by a financial market under consideration, while a(t) is a continuous function and f()..)...
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