Search

In urban traffic network, the traffic flow within several adjacent intersections is strongly relevant and traffic congestion happened on one road section will probably result in cascade of regional congestion. In this paper, we try to optimize each traffic section state to a desired consensus state in traditional subarea. Because of the difficulty to execute real experiment, we apply ACP computational experiments method to realize the process. Firstly, we establish a regional road network traffic model and set up traffic state equation with traffic density as traffic state and leaving proportions of traffic flow on sections during effective green per cycle as control input. Secondly, we design a state feedback control strategy to regulate the leaving proportions of each section which indirectly reflects the effective green time, according to the difference between real-time traffic states and desired traffic consistency state. Thirdly, we apply computational experiments method to find the right value of leaving proportions indexes which will make section traffic state converge towards the desired consensus states and balance the distribution of traffic in overall regional traffic network. The MATLAB simulation results show the feasibility and efficiency of the proposed method.

With the fast developing of Internet and intelligent device, information security issue is becoming much more important every day. More and more researchers are attracted to software security testing study. Most of them put their works on software access control model based testing, which takes into account information mainly on multi-dimensions, like roles, permissions and contexts. But the key disadvantage of access control model based testing is its model are hard to be built in many circumstance, for example, to describe requirement "picture A is only allowed to be copied twice outside terminal B", researcher has to extend the original model with hierarchy status and priority sub models. To overcome this disadvantage, this paper present a framework of data oriented access control testing method, which focus mainly on data and its actions instead of role, permission and contexts. Though experiments, this paper also proves that the method is much more instructive than access control model in test cases automatic generating.

Introducing the trust evaluation into the access control for the service requester in a distributed network environment could be helpful for enhancing the precision and security of authorization decisions, special to the strange requesters. The existing researches of the trust evaluation could be divided into the objective means and the subjective means. The subjective evaluations could be used to dynamically measure the user's trust degree according to the reputation based on its past actions. But it cannot work when the interaction experience with the user is absence. Compared with other subjective evaluation models using the probability theory, the fuzzy based model could exactly depict the unsure and fuzzy phenomena in process. But the existing fuzzy method based on the fuzzy synthetic evaluation needs to do complex calculations between trust vectors. And the chosen operators are not enough accurate. In this paper we promote a comprehensive trust evaluation framework was a fusion of objective and subjective means. An initial trust view for user is provided based on the certified trust and a reputation is derived by the fuzzy synthetic evaluation method based on user's past actions. The proposed fuzzy method can avoid complex calculations between trust vectors, and adopts a more accurate operator to avert the information wastage.

This paper briefly introduces the network boundaries can be effectively protected using network defense in depth system and the shortcomings of its technical means. Then introduced the data mining technology applications in the firewall policy optimization, traffic identification, intrusion detection technology areas at different levels of defense in depth, and lists a variety of specific application modes, which can effectively enhance the dynamic adaptation and automated optimization capabilities of defense in depth system to a wide range of network attacks and traffic flow changes.

In order to ensure the security of Web Geographic Information System in network transmission, the vector map data can be encrypted in the way of byte by byte using the chaos system to design encryption arithmetic. In this way of encryption, it should firstly make sure the parameter of Logistic mapping, secondly the logistic mapping should be the key stream generator, which would be design to convert block cipher Data Encryption Standard into sequential cipher, finally the result of encryption should be real-time and key stream longness of plaintext and cipher text would be the same. In this way the impression of encryption would be more secure and efficient. The experiment showed that this arithmetic had less error code diffusibility and efficiency was well.

Division approach of traffic control Sub-area is an important aspect for city traffic control. Aim at this problem, based on analyzing relative factors for traffic sub-area division, a new method with grey relation degree is put forward, this new method is not only easy to realize, but also able to describe the relation between intersection Quantitatively. How to realize this method is given in this paper, and the example proves the effectiveness of the method.

The typical intersection traffic flow control ways play poor role in saturated status, in order to resolve this problem, at first, the intersection control features under saturated status is analyzed, then by the queue length detection by video detection way, a new control way with threshold and rule is put forward, in which three control stages are included. Simulation result shows that this method has more effectiveness than the Webster's method when traffic flow is saturated.

On the basis of relation between driver's decision when vehicle-cross action is done in the unsignalized intersection, the driver's decision on minor time and space scale is analyzed, and the expression for safety factors and speed factors for traffic conflict vehicles in the unsignalized intersection is put up, then the utility function for vehicle-cross action is put up too. With these work, the model of driver vehicle-cross action in the unsignalized intersection is built up with dynamic game theory, and the Nash equilibrium for dynamic game process is analyzed. At last, the game model is verified by simulation, result shows that the game model is able to reflect the development result of traffic conflict under different condition, and it is logical to study driver action using dynamic game theory.

Aiming at the intelligent control for reheating furnace combustion, a kind of genetic algorithm-based intelligent control method is presented. The performance index of the controller is a function that consists of error, output, rising tune and overshooting of the system. A group of optimum intelligent control parameters are acquired with the aid of global search ability on line based on real time error. Application results show that the combustion control system has good dynamic and static performances, adaptive capability and robustness.

Driver fatigue is one of the main causes of traffic accidents. Many researchers believe that electroencephalography is very accurate and promising to detect driving fatigue, but so far, the research results have been variable. Through simulation experiments, this paper found when driving at night, delta band varies significantly with the degree of fatigue. The results have implications for real-time automatic detecting driver fatigue at night and are helpful for future development of driver fatigue countermeasures.

Electrocardiogram (ECG) indicators are widely used in driver mental workload studies. Because ECG is always recorded continuously in experiments, ECG indicator data often have trend. To make follow-up data analysis faster and more reliable, ECG indicator data should be preprocessed to remove or extract the trend according to the aim of the experiment. However, most researchers tend to ignore this point. Based on time series theories, this paper proposed a set of methods to preprocess ECG indicator data series. In this paper, the data preprocessing method was described in detail. And an example was given to illustrate and prove the validity of the method.

Considering the traffic organization project and traffic signal control project of the small and medium-sized cities in China, based on the dynamic optimization theory of operations research, this paper puts forwards the method of optimization design between the traffic organization and the traffic signal control of urban traffic, sets up the frame of the dynamic optimization. The whole design of the dynamic optimization is divided into three stages, the first stage, based on the original traffic organization project, the traffic signal control project is optimized, the second stage, based on the optimized traffic signal control project after the first stage, the traffic organization project is optimized, the third stage, based on the optimized traffic organization project after the second stage, the traffic signal control project is optimized again, finally the best project is got. This paper takes the conference intersection of HuaiRou district for example, gets the dynamic optimization project between the traffic organization and the traffic signal control, and it is found that this method is better than the past methods after the analysis by computer simulation.

Vehicle navigation system (VNS) is an important system in intelligent transportation system (ITS). Floating vehicle data detection system is an important part of VNS. The paper introduces the VNS project in Beijing and discusses selection of floating car used in data detection system of Beijing. Also the paper gives basic structure of floating vehicle data detection system and the functions of the system. At last, a test system is built to testify the practicality of the floating vehicle data detection system. The results show that the system works well and has good potential market in Beijing

In this paper we present an approach based on multi-agent technology to realize optimal intersection control. First description and function of intersection agent and phase agent are given, then with an example, the whole structure of the intersection control approach and its intensive learning process are showed. Simulation test fully indicates its effectiveness and reliability.

On the basis of agent technology, this paper focuses on a study of area traffic flow coordination control. The composition and structure of agents for area traffic flow control is discussed and the coordination strategy of the intersection agent is described. On the basis of this study, some simulations on a sample road net are preformed by analyzing the simulation results. The feasibility of using agent technology to study area traffic coordination control is asserted.

By carefully controlling the shape of single-mode fiber taper, an acousto-optic switch with 24 dB extinction ratio, 0.1 dB insertion loss and 20 /spl mu/s switching time is achieved for the first time.

Null coupler with very high splitting ratio of 100,000:1 and low excess loss of 0.1 dB is reported. The control of the splitting ratio and loss is studied. The switching function is demonstrated by an acoustooptic modulation experiment.