On Management And Control Systems Of Urban Traffic Signals

Transportation system is so important as the arterial blood networks of the human being in the society that have become a bottleneck in the development of economy. In the ancient china, mere are rather a few history records of this system, which imply that the human beings have paid attention to the system for too many years. The traffic problem in the urban is one of the various pattern problems in the transportation system. Traffic and Transportation means the displacement of the human being or the object in the large scope of essential view, this is the mankind or thing transport from place to another in a particular time. In a concrete view, they mean that the process in the displacement of the mankind or thing by using the infrastructure facilities (such as railway, highway, airline, port and station) and the instruments (such as bus, vessel, and plane).The validity of the economic system in modern society depends on the velocity and the quantity of the flows of human beings, the logistics, the energy, the information and the monetary. Traffic and transportation system is including in the realization patterns of the five flows and that caused their importance and verticality. The industries in the modern traffic and transportation exalted their kernels in the rotate of the social economy, especially, in the most recent, the logistics has been found as the third origin of profit, and the urban traffic system is a very important special field in the various modern of the transportation.Traffic problems existed, to some extent, even before the invention of the car, which ushered the age of automobile transportation. But the problems were relatively small and isolated, and did not provoke much thought for their solution. The automobile changed all that in a big way, and by the middle of the 20^th century traffic problem were big and commanding much attention. Many scholars have devote their effects to the researches in the area. By 1950,scientists from many walks of life came forward with attempts to model the movement of traffic, with the ultimate goal of finding amelioration to traffic problems.In 2001,Professor Liu Jiazhuang come from Shandong University, my advisor, has proposed a solution in a system view to the urban traffic congestion problem by three hierarchical layers and steps, this is the optimum design and modification of the urban traffic networks at first; then we lay our importance on the orientation of the networks; In the premise of accomplishments about the former two steps, the traffic management will be the last and most urgent method to the problem. All these ideas were build on the ground of the two essential outlets of the congestion problem, the construction of the traffic facilities as quickly as possible and the enforce the management after the construction. The ideas of Prof. Liu have been influenced in the area of Operations Research Society of China. And his several Ph.D. students have partly realized his former two ideas in their research papers and doctoral dissertations. In this paper, I would continue to take the third ideas into realization. The paper wants to contribute some new concepts andtechniques to the signal control systems, which is a key method in the management of traffic and transportation.The problem of traffic signal control has been studied extensively. The general objectives of traffic signals control are to improve safety and to enhance mobility for the drivers, Mathematically, they must first be to reduced to quantitative objectives. Typically one would like to set up the control problem as a system optimization problem in the library research on the signal control, by defining an objective function and seeking an optimum for this function. This function will depend on certain control variables and control parameters of the system. I want to devote some studies on the management and control in new techniques, which would be show explicitly in the following contents.The traffic signal has first been used to manage the traffic flows in 1868 and the history has been more than one hundred years till now. It has developed ceaselessly from using the burning of the petrol fume to the automatic thoroughly with the development of the science and technology, with the change of the management concept of the traffic simultaneously. The main purpose of the traffic signals is to split the traffic flows that conflict each other when the pass the intersections in the same time, and it lets the flow pass the intersections chronologically and sequence and then the traffic flows fluid fluently when the conflicts disappeared. At the same time, the traffic signals have other functions to organize, control the directions and quantities of the traffic flows, as well as to justify the traffic rules and fluency. But in the modern time, there are so many automobiles want to pass the intersection at the same phase and the capacity of an intersection or arterial network, congestion is bound to spread, with queues growing in length and duration. The situation is so often to us that illustrate the present control techniques are limited and urgent to be improved.The former techniques used in the signal control lie so much on implicit mathematical models, on the finite form-organized control patterns, which are not compile well with the transportation system, and so the effectiveness cannot appreciate of usI1718l92021lThe fuzzy control techniques that developed vastly in recent years are used in the paper, with which we combined the traditional control patterns so as to control the signals in a intelligent way. The main idea of the technique we used in the paper is the traditional control patterns function when the quantity of the traffic flows is so small as well as extreme large during the midnight or the rush hours, pre-determined patterns are used in this case. The fixed time patterns are determined by use of optimization programs111'12' M'based on the real-time traffic data. A real-time fuzzy control technique is functioned in the other time. We developed a hierarchical fuzzy control system to realize the idea of Prof. Liu.In the hierarchical system view, the whole urban traffic system would be considered as a large most upper system, then the arterial network considered as the lower system and the each intersection.in the arterial lanes are regarded as the lowest system. A concrete and reasonable hierarchical system has been built up, and now we solve the problem in the hierarchical system.First of all, we considered the fuzzy control methods of an isolated single intersection, then the intersections in the arterial road would be considered by the fuzzy control techniques similar to the isolated case. The whole urban traffic system will be considered after the former two case at last. Thus we contribute a system control pattern from the "point" to "line" then to "area". The purpose of the research is as same as the library control techniques, which have been used in the signal control successfully or unsuccessfully. This contents of the hierarchical system is the main contentof the paper, some other techniques also be used in the optimization of the control system, such as the artificial neural network etc, which has been used to extract the fuzzy control rules. The graph theory also consists in the paper chapter 5 when we consider the privilege development of the pubic transportation system. Which be considered by us as a way to the congestion problem very useful and very effective in the urban nowadays considering the traffic condition in our many cities.The following is the five chapters of the paper:Chapter 1 is introduction. First, I introduce the motivation and the background of the research, then we introduce some terminologies and notes in the paper for the integrated narration as well as some theories and methods of operations research and optimization which used in the latter contents, then we also exemplify some fundamental theory and steps about fuzzy control and the elementary process of the artificial neural network, the combination reasons of which are also included. At last, the main objectives and organization of the thesis are proposed.Chapter 2 described the fuzzy control technique of a single isolated intersection. When we used the fuzzy control, the effectiveness of traditional control patterns in some special traffic flow condition are also considered. In the realization of the fuzzy control process, the artificial neural network technique is taken intelligently. Using the real-time traffic flow data captivated by the examination instruments in the intersection, the fuzzy signal control system can self-organized the fuzzy control rules, which is influenced the validity of the system. And so, the system have such intelligent abilities as self-study, self-organization, self-coordinated. The two processes have been numerically simulated, the appreciation results show that the methods we taken are effective.Chapter 3 considered the design and realization of the arterial and area-wide fuzzy control system after the precision research of the traffic flows. The complexity and condition for the line control traffic signal system are analyzed as well as the area-wide system at first. Then we presents the design of the two signal control and coordinate systems by the technique as similar as the point system. Pay much attention to the most complicated complexity of the area-wide signal control system, we dominatingly research two particular area intersections by which almost all the area are consisted. This can be taken as the transitions to the true area-wide control naturally. The main techniques used in the design strategies are also the fuzzy intelligent methods.Chapter 4 proposed a effective and valid solution to the traffic congestion problem in many Chinese cities nowadays, i.e. the privilege development for the public traffic systems. At first, the important and urgent of the public traffic system to the traffic congestion problem are given. Analyzed the convenience and agile of the public traffic systems such as the metropolitan subway, the bus, but the price for developing the subway is much more than the bus, which is main pattern to taken by citizens in many cites, and the privilege of the bus is regarded as the most economical way to develop the public traffic system. After considering the maximal independent sets problem and the maximal weighted independent sets problems carefully, the algorithm of the optimum design of traffic signal phases are proposed, which is the way to we consider the privilege of the bus. The graph theory has also presented a good application in the transportation research. Some effective strategies of the privilege of the bus have been present based on the graph theory. Chapter 5 is the end, which summarize the main contents of the thesis. The expectation of the fuzzy traffic signal control system is presented. At first, the weakness in the techniques of the paper is considered and the methods to improve the effective of the system are also presented. Particularly, a new problem was proposed, i.e. the partition of the traffic intersections to smallparts in the area-wide control system. The mathematical programming model and the combinatorial optimization properties are also set up as well as the complexity of the problem. Finally, the signification and value of the fuzzy traffic signal control system is pointed outThe following is the innovation and achievement points of the thesis:1. In the single isolated intersection traffic signal control case, the combine of the fuzzy control techniques and the artificial neural networks are proposed, which not only exalt the advantages of the fuzzy control techniques, but also optimum design the fuzzy control rules and the control parameters. Thus make the signal control systems have the intelligent abilities of self-study, self-organization, self-coordinated, and the approaches in the paper simulated by numerical examples, which show the validity and reasonable of the techniques.2. Proposed the fuzzy control systems of the arterial networks and area-wide networks individually. The concrete and precise parameters of the control and coordinated processes are chosen carefully base on an analysis of the complexity of these rather complicate realistic systems. The traffic flows in the arterial networks and the area-wide networks are also considered carefully.3. Present the solutions to the privilege development of public traffic and transportation systems. Some concepts and algorithms in the Graph theory is build up in the thesis to solve the problem, Especially, the properties and algorithms about the maximal independent sets and the maximal weighted independent sets are given. The management of the traffic signals is realized by the privilege of the bus, which is the most convenience and economical pattern in the public transportation models. Finally, the problem that is how to divide the whole area-wide network into small partitions in a reasonable technique. The original and simple discusses are proposed in the thesis.