This paper investigates modeling, analysis and design of networked control systems (NCSs), which are of great interest due to the advantages presented here but also are technically complex because of the challenges of this class of systems such as delay and PACKET-DROPOUT. Firstly, NCSs with PACKET DROPOUTs are studied. Markov chains are introduced to describe historical behaviors of PACKET DROPOUTs. By this method which introduced, general models are derived under single PACKET transmission protocols. Further more, controllers are designed to stabilizing the resulting closed-loop systems. Secondly, by above method an inverted pendulum which was controlled in a network with delays, is controlled in a network through PACKET-DROPOUTs. simulation results show the effectiveness of the above method.

This paper addresses control design in networked control system by considering stochastic PACKET DROPOUTs in the forward path of the control loop. The PACKET DROPOUTs are modelled by mutually independent stochastic variables satisfying Bernoulli binary distribution. A sliding mode controller is utilized to overcome the adverse influences of stochastic PACKET DROPOUTs in networked control systems. Firstly, to determine the parameters of switching function used in the sliding mode control design, an improved genetic algorithm is applied. The proposed improved genetic algorithm provides a fast convergence rate and a proper dynamic performance in comparison with conventional genetic algorithms especially in online control applications. Then, an adaptive neural sliding mode control based on radial-basis function neural network approximation is proposed to eliminate chattering phenomenon in the sliding mode control. A numerical example is given to illustrate the effectiveness of the proposed controller in networked control systems. The results show that the proposed controller provides high-performance dynamic characteristics and robustness against plant parameter variations and external disturbances.

In this study, a robust controller is designed for fuzzy network control systems (NCSs) using the static output feedback. Delay and data PACKET DROPOUT affect on the stability of network control systems, and therefore, the asymptotic stability condition is established considering delay and data PACKET DROPOUT. Delay is time-varying while the lower and upper bounds for delay is defined, and the number of data PACKET DROPOUT is unknown. Data drift is also an important phenomena that may occur when data is transmitted from sensors to the controller and from the controller to actuators. This phenomenon is modeled as a stochastic variable with a probabilistic distribution. For stability analyses, Lyapunov–Krasovskii functions, which depend on the limits of delay and data PACKET DROPOUT, are used. Results of controller design are derived as Linear Matrix Inequalities (LMIs). A numerical example is adopted to show the effectiveness of the proposed approach.

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The present research was done with aim of exploring reasons for DROPOUT of one rural girl student. The method of present research is descriptive and by narrative research approach. This research focused on rural girl student, has dropped out. For gathering data were used of semi-structured narrative interviews and survey notes. In the process of analysis have been used of narrations and encoding. In analyzing of narrations has been leveraged of Struass and Corbin’ s paradigm pattern {1990}. The results show that central category in DROPOUT of this student is environmental poverty {Family and educational environment of the village} is affected by different factors such as economical poverty, illiteracy of parents, gender discrimination, student employment at home, distance to home and co-educational student; also background like culture faith of rural people, employing teacher soldier and effect of the group of peers have been effective along with above situation. These factors were influenced by the centralized structure of educational system include effective factors, the lack of educational content fit with needs of environment and school schedule with rural situations, have led to dropping out of student.