The recent advances in integrated circuit technologies, microprocessor hardware, wireless communications, embedded systems and technologies as well as the emergence of Ad-hoc networking, made up the concept of wireles...The recent advances in integrated circuit technologies, microprocessor hardware, wireless communications, embedded systems and technologies as well as the emergence of Ad-hoc networking, made up the concept of wireless sensor networks. Regarding the nature of sensors and the nature of the environment of deployment sensor networks are exposed to many attacks more than any other networks, therefore new strategies and protocols of security must be defined for these networks taking into consideration the characteristics of sensors as well as the architecture of the network. In this paper we propose a lightweight implementation of public key infrastructure called cluster based public infrastructure (CBPKI), CBPKI is based on the security and the authenticity of the base station for executing a set of handshakes intended to establish session keys between the base station and sensors over the network used for ensuring data confidentiality and integrity.展开更多
This article implements maximum power point tracking(MPPT)based on the improved hill-climbing algorithm for photovoltaic(PV)systems feeding resistive loads.A direct current-to-direct current boost converter is inserte...This article implements maximum power point tracking(MPPT)based on the improved hill-climbing algorithm for photovoltaic(PV)systems feeding resistive loads.A direct current-to-direct current boost converter is inserted between the PV system and the load to achieve matching.The converter is managed using MPPT based on the hill-climbing algorithm.The objective of this paper is to optimize the code program to achieve the best compromise between accuracy and rapidity by implementing this algorithm using a microcontroller.Two PV systems are tested under identical meteorological conditions.In the first,an improved hill-climbing MPPT controller is used whereas,in the second,the conventional version is employed.The experimental results obtained show a signifi-cant enhancement in terms of speed for the improved algorithm with a value of 0.4 s for the response time and 3%for the oscillation power;those values remain satisfactory in terms of precision of the algorithm compared with the conventional system studied and the compared algorithm from the literature.展开更多
文摘The recent advances in integrated circuit technologies, microprocessor hardware, wireless communications, embedded systems and technologies as well as the emergence of Ad-hoc networking, made up the concept of wireless sensor networks. Regarding the nature of sensors and the nature of the environment of deployment sensor networks are exposed to many attacks more than any other networks, therefore new strategies and protocols of security must be defined for these networks taking into consideration the characteristics of sensors as well as the architecture of the network. In this paper we propose a lightweight implementation of public key infrastructure called cluster based public infrastructure (CBPKI), CBPKI is based on the security and the authenticity of the base station for executing a set of handshakes intended to establish session keys between the base station and sensors over the network used for ensuring data confidentiality and integrity.
文摘This article implements maximum power point tracking(MPPT)based on the improved hill-climbing algorithm for photovoltaic(PV)systems feeding resistive loads.A direct current-to-direct current boost converter is inserted between the PV system and the load to achieve matching.The converter is managed using MPPT based on the hill-climbing algorithm.The objective of this paper is to optimize the code program to achieve the best compromise between accuracy and rapidity by implementing this algorithm using a microcontroller.Two PV systems are tested under identical meteorological conditions.In the first,an improved hill-climbing MPPT controller is used whereas,in the second,the conventional version is employed.The experimental results obtained show a signifi-cant enhancement in terms of speed for the improved algorithm with a value of 0.4 s for the response time and 3%for the oscillation power;those values remain satisfactory in terms of precision of the algorithm compared with the conventional system studied and the compared algorithm from the literature.
