Photovoltaic (PV) systems have attracted increasing attention in last years as well as Wireless Sensor Networks (WSNs), which have been used in many application fields. In PV plants, especially in ground installations...Photovoltaic (PV) systems have attracted increasing attention in last years as well as Wireless Sensor Networks (WSNs), which have been used in many application fields. In PV plants, especially in ground installations, a lot of thefts and damages occur due to the still high cost of the modules. A new experimental WSN ad-hoc has been designed to be an anti-theft alarm system. Each node of the network is directly installed under each PV string and it is equipped with an accelerometer sensor capable to detect a minimum displacement of the panel from its steady position. The WSN presents a star topology: a master node cyclically interrogates the slave nodes through RF link. It collects all the nodes responses and communicates though a RS-232 interface with a control PC checking the network status. When a slave node detects an alarm, continuous messages are sent to the control PC which turns on all the alarm signaling systems. The control PC is equipped with an open source operative system and software and provides for SMS, e-mail and sound-light signaling in case of alarm. It also communicates with a remote server where all the WSN information is stored. A first low cost experimental WSN has been already installed and it is working properly.展开更多
A d hoc网络是由彼此对等的、自主的无线节点组成的自组织多跳网络.由于A d hoc网络的特点,使得网络拓扑设计的优化问题变得更加复杂,传统的方法甚至难于实现.本文应用微粒群算法,构造了一个适合自组网网络架构设计的运算法则,建立了一...A d hoc网络是由彼此对等的、自主的无线节点组成的自组织多跳网络.由于A d hoc网络的特点,使得网络拓扑设计的优化问题变得更加复杂,传统的方法甚至难于实现.本文应用微粒群算法,构造了一个适合自组网网络架构设计的运算法则,建立了一个新的对约束的处理技巧,通过引入共生机制,实现了网络设计在约束下的多目标优化设计,其微粒群的解关于约束是理想的,解集间是非次等的,不分优劣.仿真结果表明,该方法是有效的,它的实时性适应了A d hoc网络结构动态的变化.展开更多
设计了一个S波段1∶4Wilkinson正交功率分配器。该功率分配器由3个1∶2 Wilkinson功率分配器二级级联构成,加入λ/4微带传输线,形成正交网络,同时对功率分配器进行了增益均衡设计,应用微波仿真软件ADS对电路进行了优化设计,给出了S参数...设计了一个S波段1∶4Wilkinson正交功率分配器。该功率分配器由3个1∶2 Wilkinson功率分配器二级级联构成,加入λ/4微带传输线,形成正交网络,同时对功率分配器进行了增益均衡设计,应用微波仿真软件ADS对电路进行了优化设计,给出了S参数仿真结果、电路版图及实物图,测试结果表明,在2.7-2.9 GHz工作频率范围内,输入输出端的驻波比〈1.3,隔离度〈-24 d B,插入损耗≤0.3 d B,相位偏差小于5°（相对于标准相位）。展开更多
文摘Photovoltaic (PV) systems have attracted increasing attention in last years as well as Wireless Sensor Networks (WSNs), which have been used in many application fields. In PV plants, especially in ground installations, a lot of thefts and damages occur due to the still high cost of the modules. A new experimental WSN ad-hoc has been designed to be an anti-theft alarm system. Each node of the network is directly installed under each PV string and it is equipped with an accelerometer sensor capable to detect a minimum displacement of the panel from its steady position. The WSN presents a star topology: a master node cyclically interrogates the slave nodes through RF link. It collects all the nodes responses and communicates though a RS-232 interface with a control PC checking the network status. When a slave node detects an alarm, continuous messages are sent to the control PC which turns on all the alarm signaling systems. The control PC is equipped with an open source operative system and software and provides for SMS, e-mail and sound-light signaling in case of alarm. It also communicates with a remote server where all the WSN information is stored. A first low cost experimental WSN has been already installed and it is working properly.
文摘A d hoc网络是由彼此对等的、自主的无线节点组成的自组织多跳网络.由于A d hoc网络的特点,使得网络拓扑设计的优化问题变得更加复杂,传统的方法甚至难于实现.本文应用微粒群算法,构造了一个适合自组网网络架构设计的运算法则,建立了一个新的对约束的处理技巧,通过引入共生机制,实现了网络设计在约束下的多目标优化设计,其微粒群的解关于约束是理想的,解集间是非次等的,不分优劣.仿真结果表明,该方法是有效的,它的实时性适应了A d hoc网络结构动态的变化.
文摘设计了一个S波段1∶4Wilkinson正交功率分配器。该功率分配器由3个1∶2 Wilkinson功率分配器二级级联构成,加入λ/4微带传输线,形成正交网络,同时对功率分配器进行了增益均衡设计,应用微波仿真软件ADS对电路进行了优化设计,给出了S参数仿真结果、电路版图及实物图,测试结果表明,在2.7-2.9 GHz工作频率范围内,输入输出端的驻波比〈1.3,隔离度〈-24 d B,插入损耗≤0.3 d B,相位偏差小于5°（相对于标准相位）。
