Internet of things (IoT) has described a futurevision of internetwhere users, computing system, and everyday objects possessing sensing and actuating capabilities are part of distributed applications and required to support standard internet communication with more powerful device or internet hosts. This vision necessitates the security mechanisms for end-to-end communication. A key management protocol is critical to ensuring the secure exchange of data between interconnecting entities, but due to the nature of this communication system where a high resource constrained node may be communicating with node with high energy makes the application of existing key management protocols impossible. In this paper, we propose a new lightweight key management protocol that allows the constrained node in 6loWPAN network to transmit captured data to internet host in secure channel. This protocol is based on cooperation of selected 6loWPAN routers to participate in computation of highly consuming cryptographic primitives. Our protocol is assessed with AVISPA tool, the results show that our scheme ensured security properties. These technologies will interact with physical phenomena by employing more constrained sensing platforms and low-energy wireless communications, therefore, end-to-end communication between constrained sensing devices and other Internet host will be a fundamental requirement of many sensing application using these technologies, this aspects that seriously complicate the design and adoption of appropriate security mechanisms especially end-to-end security mechanisms.

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In this article, the meta-heuristic algorithm PSO with PI fuzzy logic controller is proposed to develop a new control strategy of bidirectional converter (CSBC), in order to improve the stability and increase the efficiency of energy flow exchange in grid-connected photovoltaic generator (PVG) Battery hybrid system. The proposed command aims to satisfy the DC Motor load demand, manages the power flows from different parts, injects surplus energy into the grid as and when need, ensure charge-discharge battery operation even under the fluctuating condition of power generation, and stabilize the DC bus voltage. This new control has been placed in the network topology, which consists of a PVG Photovoltaic Generator, grid-connected DC/AC converter, storage battery and DC motor load. A bidirectional buck-boost converter is used for optimum exploit of power from PVG along with battery charging/discharging control, and for feeding DC motor load. The effectiveness of the proposed control scheme is demonstrated by using MATLAB / Simulink program. The results obtained, show that the proposed control provided the system with the stability of Vdc voltage, and contributed to improving the speed produced by the DC motor load. The results have been compared with the conventional control.