In recent year, ad-hoc network technology has gained attention, which consists of not access points and base stations but of wireless nodes. In this network, it is difficult to maintain the whole data flow because of the absence of access points as the network administrator when nodes share the data. This paper proposes the security camera system which has only nodes sharing the taken pictures and has the robustness against the data destroying. The sender node cannot know whether packets are received or not by neighboring nodes in broadcasting because of a unidirectional communication. So in our proposed method, the sender node selects the receiver node from neighboring nodes, and they communicate with each other. On the other hand, neighboring nodes listen to packets between the sender node and the receiver node. After that, this method guarantees nodes of more than 1 which receive a data in broadcasting. We construct the security camera system using wireless nodes with the IEEE 802.15.4 specification and show the performance for security. At last, using the simulator we show the efficiency in the large environment, and conclude this paper.
This paper is concerned with the problem of enhancing the stability of a parallel-flow heat exchanger equation with diffusive terms, under boundary control and boundary observation. By introducing two new variables, the system is expressed as two decoupled subsystems, where each subsystem is exponentially stable. In order to enhance the stability of the whole system, we use a backstepping method to construct infinite-dimensional observer-based controllers for each subsystem. The Lyapunov method is successfully applied to prove the closed-loop stability with the controller. This paper gives the controller design for the case of collocated sensor and actuator as well as for the anticollocated case.