Simultaneous actuator and sensor fault reconstruction of singular delayed linear parameter varying systems in the presence of unknown time varying delays and inexact parameters

In this article, robust fault diagnosis of a class of singular delayed linear parameter varying systems is considered. The considered system has delayed dynamics with unknown time varying delays and also it is affected by noise, disturbance and faults in both actuators and sensors. Moreover, in addition to the aforementioned unknown inputs and uncertainty, another source of uncertainty related to inexact measures of the scheduling parameters is present in the system. Making use of the descriptor system approach, sensor faults in the system are added as additional states into the original state vector to obtain an augmented system. Then, by designing a suitable proportional double integral unknown input observer (PDIUIO), the states, actuator, and sensor faults are estimated. The uncertainty due to the mismatch between the inexact parameters that schedule the observer and the real parameters that schedule the original system is formulated with an uncertain system approach. In the PDIUIO, the uncertainty induced by unknown inputs (disturbance, noise and actuator, and sensor faults), unknown delays, and inexact parameter measures are attenuated in H8 sense with different weights. The constraints regarding the existence and the robust stability of the designed PDIUIO are formulated using linear matrix inequalities. The efficiency of the proposed method is verified using an application example based on an electrical circuit.Peer ReviewedPostprint (author's final draft

Design of unknown input fractional order proportional–integral observer for fractional order singular systems with application to actuator fault diagnosis

International audienceThis study proposes the design of an unknown input fractional order proportional–integral observer for fault diagnosis of linear fractional order singular (FOS) systems. The considered system is rectangular in general form. The necessary and sufficient conditions for the existence of the proposed observer are derived, and a systematic design approach is presented. The proposed observer is non-singular, and uses only the original coefficient matrices to estimate the norm-bounded actuator faults. Also, the unknown input appearing in measurement is considered and the effects of unknown inputs are decoupled from observer dynamics. By introducing a continuous frequency distributed model and using indirect Lyapunov approach, the convergence conditions of the proposed observer are derived in terms of linear matrix inequalities. Furthermore, for a class of non-linear FOS systems with both output disturbances and input uncertainties, a non-linear observer is developed based on the proposed design approach. The existence and convergence of this observer are proved. Finally, the effectiveness of the proposed method is illustrated via two examples

Evaluation of Challenge between Internet and Mass Media in News Diffusion with the Use of Stochastic Process

Because of the newness of Information Technology (IT) and Internet in the world, and because of intrinsic constraint of multimedia and traditional news systems such as: newspaper, bulletin, radio and television in interactive communication, diffusion of news and information in Internet has possessed special situation. But it is possible sometimes that the use of internet doesn’t achieve anticipated and expected objectives for leaders of media. Because every media is appropriate to fulfill special objectives. Namely, sometimes using the Internet and occasionally using the mass media, can be efficient. In this article, it is tried with using stochastic process and adapting epidemic model for mass media behavior and also introducing a new mathematic method for analyzing Internet behavior concerning diffusion news in a period of time and the behavior of media is analyzed. Therefore, some features such as: the mean number of person hears news, the mean of time continues to hear news N-person, and other important parameters are studied