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Shen X.,Changan University | Wang L.,Changan University | Li X.,China Transport Telecommunications and Information Center
Journal of Information and Computational Science | Year: 2014

This paper focus on the multi-objective routing and dispatch problem for a given hazardous materials shipment with multiple time windows and time varying attributes. Section 1 consists of background and purpose of the research. Section 2 proposes a mathematical model for this problem by introducing the punishing functions to convert time windows into penalty variables of model. Section 3 develops a two-step solving algorithm for model, of which the first step is to identify the non-dominated paths with specific dispatch time based on the improved dynamic programming method, and the second step is to choose the optimal alternatives from non-dominated paths by the application of the grey correlation analysis method. Section 4 carries out a case study to test the methodology proposed in the paper. The results show that the model and the two-step algorithm can effectively solve road hazardous materials transportation routing and dispatch problem. 1548-7741/Copyright © 2014 Binary Information Press. Source

Xie C.,China Transport Telecommunications and Information Center
International Conference on Geoinformatics | Year: 2016

Selecting the official land cover data from the government-led Geographical Conditions Survey of China and utilizing the method of global and local spatial autocorrelation based on grid processing, the authors analyzed Yingkou City's characteristics of land cover spatial autocorrelation pattern. The study suggested following conclusions: 1) The Global Moran's I index of all types of land cover in Yingkou City were greater than 0.35, whose confidence level was higher than 95%. The results showed that there are strong spatial autocorrelations among different types of land cover in this area. 2) The Local Moran's I Index showed that there are significant differences in various types of land cover's coverages and ranges of the spatial aggregation or anomaly. 3) Using the cross-variable correlation analysis, the authors discussed the relationships and distribution patterns of different land cover types. This research was helpful to reveal the correlation between the spatial autocorrelation of land cover and types of land cover. The study above was also suitable for large-scale regional application, and the results were significant important for the geographical conditions monitoring. © 2015 IEEE. Source

Sang L.-Z.,China Transport Telecommunications and Information Center | Yan X.-P.,Wuhan University of Technology | Wall A.,Liverpool John Moores University | Wang J.,Liverpool John Moores University | Mao Z.,Wuhan University of Technology
Journal of Navigation | Year: 2016

The information on the Closest Point of Approach (CPA) of another vessel to own ship is required in a potential collision situation as it helps determines the risk to each vessel. CPA is usually calculated based on the speed and direction of the approaching ship neglecting the Change Of Speed (COS) and the Rate Of Turn (ROT). This will make the CPA less useful. To improve the CPA calculation, Automatic Identification System (AIS) information containing the Speed Over Ground (SOG), Course Over Ground (COG), COS and ROT is used. Firstly, a model using these four factors is built to predict ship positions better. Secondly, a three-step CPA searching method is developed. The developed CPA calculation method can assist in informing the navigation decisions and reducing unnecessary manoeuvres. Through the analysis of a real collision scenario, this paper shows that the proposed method can help identify and warn of anomalous ship behaviours in a realistic time frame. Copyright © The Royal Institute of Navigation 2016 Source

Wu D.,Wuhan University of Technology | Lu H.,Wuhan University of Technology | Chen W.,China Transport Telecommunications and Information Center | Yang X.,Hubei Station of Surveying Products Quality Supervision and Checkout
ICTIS 2015 - 3rd International Conference on Transportation Information and Safety, Proceedings | Year: 2015

BeiDou pseudolites (BPLs), ground-based BeiDou-like signals transmitters, are capable of augmenting positioning accuracy, reliability, availability of the BeiDou satellite navigation system. However, implementation of the BPLs lead to another problem-the 'near far problem', where the satellite signals are blocked by the signals from a BPL. One of the promising solutions is to pulse the BPL signals to reduce the interference. Because the existing pulsing schemes, i.e., the RTCM SC-104 and the RTCA SC-159 are designed for the GPS signals, they cannot be simply adopted in the BeiDou system due to the different signal structures. Therefore, a dedicated BPLs signals pulsing scheme is proposed in this paper. Two critical parameters-duty cycle and pulse pattern which characterize a pulsing scheme are analyzed and determined in the proposed scheme. Besides, the transmission power requirement is explained in details. The simulation proves that this scheme meets all identified requirements, making it a viable solution to mitigate the near-far problem. © 2015 IEEE. Source

Wang L.,University of Waterloo | Li J.,University of Waterloo | Duguay C.,University of Waterloo | Li D.,China Transport Telecommunications and Information Center
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015

Snow is a very important component of the climate system. It can influence the energy budget of the atmosphere and hydrological system significantly. The main goal of this paper is to use remote sensing and geographical information system techniques to analyze the spatial and temporal variations in regional scale and to find the relations between meteorological parameters and the snow albedo for the future modeling in snow albedo study. The results revealed spatial and temporal variation throughout different months during the winter season. In addition, the Pearson correlation coefficient analysis showed partial correlation between snow albedo and meteorological variables, which can be used to model snow albedo in some hydrological studies. © 2015 IEEE. Source

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