1、英文原文 An Intelligent Guiding and Controlling System for Transportation Network Based on Wireless Sensor Network Technology Abstract This paper proposes architecture based on Wireless Sensor Network (WSN) technology for Intelligent Transportation System (ITS) of a transportation network. With the help
2、 of WSN technology, the traffic info of the network can be accurately measured in real time. Based on this architecture, an optimization algorithm is proposed to minimize the average travel time for the vehicles in the network. Compared to randomly-chosen algorithm, simulation results show that the
3、average speed of the road network is significantly improved by our algorithm, and thus improve the efficiency of the road network. Some extended applications of the proposed WSN system are discussed as well. 1. Introduction Transportation plays an important role in our modern society. How to efficie
4、ntly exploit the transportation capacity of the existing transportation infrastructure receives a lot of attention from the researchers across the world. The Intelligent Transportation System (ITS) has been proposed by many researchers to solve the problem. ITS comprises of three main sub-systems. T
5、hey are surveillance sub-system, analysis and strategy subsystem and execution sub-system. The execution subsystem can be a traffic control sub-system, a vehicle guiding sub-system, or a navigation sub-system. The surveillance sub-system measures the traffic information such as the vehicles location
6、, speed, number of the vehicles on the road, etc., using certain type of sensor, such as inductive loops 1 or ultrasonic sensor 2. A new method based on video analysis is now under development 1；3. The analysis and strategy sub-system optimizes the traffic flows based on the measurements from the su
7、rveillance sub-system. Various algorithms are proposed for this purpose, some typical examples follow. Papageorgiou et al. summaries some implementations on fixed-time strategies and trafficresponsive strategies for isolated strategies and coordinated strategies in 4； In 5, Shimizu et al. propose a
8、balance control algorithm to optimize the congestion length of the whole transportation network； in 6, Di Febbraro presents a hybrid Petri Net module to address the problem of intersection signal lights coordination. The control sub-system controls the signal lights on the intersection. The guiding
9、sub-system provides the real-time traffic information for the drivers to select the best route. The navigation sub-system uses satellite signal such as GPS to locate the specific vehicle, and with the help of electronic map, select the optimal route for the vehicle. One shortage of the systems menti
10、oned above is that the sensors can only detect the vehicles in a fixed spot. They can not track the vehicles out of the spot. Clearly, if we can monitor and measure the traffic status dynamically in real time, an efficient traffic control will be easier to realize. With the development of microelect
11、ronic and computer technologies, the low-power-consumption, low-cost and relatively powerful wireless sensor network (WSN) technology has been applied in many areas7-9. However, the application of WSN in the traffic control system is rarely documented. In 10, we proposed a WSN-based system for an ef
12、ficient traffic control in an isolated road intersection. This paper extends our previous work to a transportation network. A WSN-based traffic control, guiding, and navigation system is proposed to optimize the traffic in a transportation network. The rest of this paper is organized as follows: Sec
13、tion 2 describes the structure of the proposed WSN-based traffic control system. Section 3 describes the optimization algorithm for the traffic network. The simulation results and some discussions are presented in Section 4. Finally, Section 5 concludes this paper. 2. System Structure 2.1. WSN Modul
14、e WSN module is a basic component in our traffic control system. As illustrated in Fig. 1, a WSN module comprises of 3 main components, i.e., RF (Radio Frequency), MCU (Micro Control Unit) and Power Supply. The RF encodes, modulates and sends the signal. Also it receives, decodes and demodulates the
15、 signal as well. MCU integrates processor and memories, where the programs resides and executes. The Power Supply supplies the power to entire module. In the proposed system, WSN modules are widely distributed on vehicles, roadsides and intersections to collect, transfer and analyze the traffic info
16、rmation. See section 2.3 for details. 2.2. Urban Traffic Network Several different facilities are installed in the urban traffic network to perform their specific functions. For example, the Signal Lights are installed in the road intersection to directly control the vehicle through the intersection
17、； the Variable Message Sign (VMS) is set up along the road side to help drivers to select the optimal route； the Navigation system (electronic-map and satellite-based positioning system) is installed in the vehicle for vehicle locating and navigation. The target of an ITS is to optimize the traffic
18、in a transportation network by controlling the signal lights in the intersections, by providing the accurate traffic information in the VMS, or by selecting the best route in the e-map. To perform the traffic control, below, we shall first have a look at the configuration of the transportation netwo
19、rk. Then, some parameters are introduced to describe traffic information in the network. By optimizing these parameters, the proposed optimization algorithm is expected to optimize the traffic in the transportation network. As a example of a real-life traffic network, Fig. 2 illustrates the road net
20、 of Fukuyama city 11. On the figure some parameters such as the link length, lane numbers, and legal speed are marked on it. In this paper, we consider the traffic system that contains 3 types of basic elements, i.e., intersection (N), Link (L) and Vehicle (V). An Intersection can be described by 2
21、parameters: 1) the phase type (the type of the vehicles on different lanes passing through the intersection simultaneously)； 2) the duration of every phase. A Link can be described by 4 parameters, i.e., the link length, lane numbers (include every turningdirection), mean speed, vehicle number. A Vehicle can be described by 5 parameters. They are: 1) the location of the vehicle, 2) the
