Level, Class, and Prospected Safety Performance of a Lightning Protection System for a Complex of Structures (LPCS)
The Standard IEC 62305 provides advanced information for the design of lightning protection of structures (LPS). In determining the position of the air-termination system, two methods are generally suggested: the protective angle method and the rolling sphere method. Adopting a 3-D graphical simulation, the “rolling sphere” method allows one: to analyze the protected volume at the building roof inside of the rolling ply surface; to verify the behavior of the designed air-termination system; to evaluate the contribution of the surrounding structures in limiting the lightning current flowing in the down-conductors. This current affects the probability of dangerous sparking and the separation distance for the protection of internal installations. This paper presents this approach by a case study of a building in a complex of structures: it highlights particularly the worst cases of the lightning impact related to the designed air-termination system.
An optimal model for tunnel lighting control systems
Abstract We present a tunnel lighting optimal control model in considering traffic safety and energy-saving problems. Firstly, the demand brightness function with relation to tunnel exterior brightness, traffic flow and speed is described. Then an actual tunnel brightness curve is derived according to lamp equipment layouts and lamp properties in tunnels. Further, a simple method is used to determine an average brightness indicator in tunnels. We present a nonlinear optimal control tunnel lighting model in meeting the demand brightness, total average brightness and minimum dimming ratio constraints and so on. Finally, the simulation results at the JiangBeiLing tunnel of Wenzhou city in China show the optimal control system can meet the demand brightness and total average brightness constraints, and have a notable energy-saving effect.
The Use of Qualitative Information in Macro-Economic Policy Analysis
The majority of macro-economic policy models takes for granted that conflicts among objectives can be assessed by means of a tradeoff analysis. Such tradeoffs imply that sacrifices and benefits of various impacts of decisions can be measured on a cardinal scale, so that a conventional macro-economic utility or welfare analysis can be applied.