Applied Mechanics and Materials Vols. 178-181

Abstract: WinCE is the foundation of Microsoft embedded, mobile computing platform, it is an open, can be upgraded 32-bit embedded operating system, and it is an electronic equipment operating system based on handheld computers. This paper designed a kind of video monitoring system based on WinCE embedded operating system and ARM9 processor core. The system can collect video information by camera, and then transmit the getting information to the remote server to monitor, the experiment result shows that the system has a good stability and real-time.

Abstract: Trucks play a significant role in transporting freight through the ground transportation systems, and it is important to be able to estimate and predict the amount of freight in a highway network. In this study, truck weight and volume data, obtained from Weigh-in-Motion stations in California, are analyzed to examine temporal and seasonal patterns. Then coupled with socio- economic variables, a hierarchical regression model is established for estimating freight demand. The model reveals that truck freight demand can be estimated by the truck annual average daily traffic along with the population, number of firms and median income at that county level. What is more, it has a predicting capability of freight weight where no truck weight data is measured. Therefore it can be served for practitioners to predict the growth of freight demand in a freeway network, and is useful to achieve the optimal flows design of cargo at all segments, regardless of whether or not weight data is available.

Abstract: Integer ambiguity resolution is a prerequisite for GPS reference station network. Due to the presence of distance errors in the double-differenced data (principally atmospheric delays), the convergence time of ambiguity in medium and long distance GPS reference station network is about a dozen minutes and even dozens of minutes. And in the case of loss-of-lock, cycle-slips or new rising satellites, the integer ambiguity value have to be redetermined over and over again. But for the application of GPS network RTK, the resolution of ambiguity needs to be determined real time as possible. This paper described techniques to predict atmospheric biases using exponent model and AR model from derived the atmospheric delays by previous epochs, which is helpful for rapid solution of ambiguity and generation of error correction in the GPS reference station network. Experiment shows that the precision of predicted atmospheric delays is about 2-3 cm using temporal- and spatial-correlation exponent model and AR model in medium and long distance GPS reference station network.

Abstract: In the multimedia device management system, because can be applied to reading information from the tags and also to communicating with the database server through the GPRS network, the RFID (Radio Frequency Identification) technology is superior to the currently widespread automatic identification (Auto-ID) technology of the barcode, so which can provide further benefits. On the basis of applying the RFID technology to the management of multimedia devices, we design a RFID-based multimedia devices management system.

Abstract: Vehicular ad hoc networks (VANETs) form when vehicles are equipped with devices capable of short-range wireless communication. Accurate wireless positioning of VANETs is a challenging task, which requires a robust wireless positioning algorithm. In this study, a quadrilateral positioning algorithm is proposed to estimate the moving vehicle node’s position in VANETs based on the wireless signal’s “distance-loss” model and geometric relationship. Furthermore, a wireless positioning experimental platform was created to test the positioning algorithm applications in field. The experimental results show that when the moving node is inside the fixed nodes, the positioning accuracy is much higher than the case that the moving node is outside the fixed nodes; when the moving node is located in the middle of the experimental field, the positioning accuracy is higher than located at the corner areas in the test field.

Abstract: The 3D visualization technology is a kind of means and methods to achieve the human-computer interaction. Instead of the discrete objects in container terminal yard, the cargo in bulk terminal yard is always being a form with particle. This paper gives a method which integrates modeling manually and real-time reconstruction automatically to achieve 3D visualization of bulk terminal yard. Since to meet the requirement of real-time rendering and also decision data computing fast, this paper designs the data structure to describe the digital stockpile formed with a hierarchy relationship between surfaces, sections and space points, and also considers the closest distance as the main condition for searching and updating an old section, to visualize the working process in bucket terminal yard.

Abstract: The security warning system need to be real-time and far detection distance. In this article, we use the method of the camera calibration in surface which is based on the method of direct Linear Transformation, and which is simple calculation and can meet the needs of the long distance detection. And on the basis of the existing methord of monocular distance measure, we improved the method which can range in safety warning only using the monocular vision to calculate the distance between the vehicle and the pedestrian who is in front of the car.

Abstract: In order to allocate the highway emergency resources rationally, with the timeliness, importance, scarcity and capital occupancy of the emergency supplies used as evaluation indexes, this paper use the analytic hierarchy process to determine the weight of each index, and use fuzzy comprehensive evaluation method to evaluate the emergency resource demands. The paper provides a comprehensive evaluation of resource requirements for highway emergency resources ,such as the highway patrol car, sweeper truck, fire engines, medical vehicles and wrecker. Through qualitative and quantitative analysis, the results are rational,effective and more consistent with reality, on which can be based in emergency resource allocation.

Abstract: A new lattice model of traffic flow is proposed by considering the information of front multiple sites with relative current. The linear stability condition is obtained by using the linear stability theory. Numerical simulation shows that the proposed model is consistent with the theoretical analysis.

Abstract: Meteorological disasters have a negative influence on highway safety operations. In order to efficiently enhancing emergency response capabilities for prevention of meteorological disasters and to carry out study of the ranking of risk factors about meteorological disasters, fuzzy mathematical method (expertise method) was applied to estimate the two indexes of risk factors of meteorological disasters in freeway normal operation: probability of risk factors and losses value of risk factors. Risk matrix method was used to analyze qualitatively and quantitatively the potential risk factors of meteorological disasters. By analyzing the potential risk factors of meteorological disasters in the normal operational process of a freeway in south China, it came to that risk level of typhoon was divided into four levers, dense fog and heavy rain were three, thunderstorms and heat were two. The result was consistent with the actual thing, and it provided a good analytic basis for follow-up emergency strategic planning.