State-Space Equations and the First-Phase Algorithm for Signal Control of Single Intersections

State-space equations were applied to formulate the queuing and delay of traffic at a single intersection in this paper. The signal control of a single intersection was then modeled as a discrete-time optimal control problem, with consideration of the constraints of stream conflicts, saturation flow rate, minimum green time, and maximum green time. The problem cannot be solved directly due to the nonlinear constraints. However, the results of qualitative analysis were used to develop a first-phase signal control algorithm. Simula- tion results show that the algorithm substantially reduces the total delay compared to fixed-time control.     

计量的空间

2018年国际计量大会（CGPM）通过国际单位制（SI）重新定义，为计量的发展和应用打开了更为广阔的空间。从计量的定义出发，用演绎和归纳相结合的方式，梳理计量涉及的要素和内容，提出“计量的空间”概念，从计量学基础、法制计量、计量的应用等不同层面阐释计量的丰富内涵。提出计量学基础包含测量理论研究、量值溯源、测量新手段、操作规范性、测量结果分析等基本要素。提出计量学基础与法制计量共同构成计量基础设施，支撑计量的产业应用。从计量的空间角度回顾了计量发展的3个阶段，展望了计量3.0时代SI重新定义可能带来的新变化。