基于GIS的高速公路养护管理信息系统的设计与开发

China is experiencing a rapid development of highway ever since 1990s. By the end of 2004, the total length of the highway summed up to 33 thousand kilometers, ranking 2n in the world. After the open of highway, the accumulation of time and traffic causes the decrease of its capability. To ensure its good quality, security and operation functions, we should take some reasonable measures to maintain it periodically. At present, a big problem is that the traditional maintain measures can no longer meet the increasing requirements. Due to the characters of highway, the relationship of various maintenance data and geographic positions is even closer than any others. If we wan to improve the quality and efficiency of the maintenance work, particularly when there is need for decision-making, a great number of data that is related to geographic positions are absolutely necessary. Evidently, Geographical Information System (GIS) has incomparably advantages in dealing with these spatial information. As a result, a management system for highway maintenance work based on GIS became inevitable for the development of the maintenance of highway. The purpose of this paper is to establish a management system for highway maintenance work base on Geographical Information System (GIS), Global Positioning System (GPS) and spatial database, to manage all kinds of problems encountered in the work, and to provide support on information and methods. My study mainly includes: (1) Analysis on the current status of the maintenance and management work; overview on the history of domestic and international highway maintenance management systems; identifying the necessity and importance for establishing a management system for highway maintenance work based on GIS. (2) Based on the requirement analysis, I proposed a general design for this management system, and discussed the objective, design principles, framework, systematical structure and function design. (3) Outdoor data collection is not only a prime way to understand the current situation of the road, but also an important method for data update after the system is put into use. This paper also intends to establish a set of plan to collect data efficiently and precisely which is based on GIS and GPS technologies. (4) The maintenance management database is a supporting platform for various maintenance decision-makings. Such decisions need the support of a great amount of data, which would cause other problems, such as the diversity of the data source, difference of data formats. This paper also discussed how to deal with these problems and establish such a database. (5) To propose an approach to assess the condition of pavement, based on GIS and related maintenance models. Among all the maintenance models, the two for assessing and forecasting pavement condition are the most important and mature. This paper also analyzed these two models and introduced them in terms of the integration of models. (6) This paper took the Guangshen Highway for example, explaining how to realize a GIS for management of highway maintenance work.

Effects of Ionizing Radiation on Three-Dimensional Human Vessel Models: Differential Effects According to Radiation Quality and Cellular Development

Little is known about the effects of space radiation on the human body. There are a number of potential chronic and acute effects, and one major target for noncarcinogenic effects is the human vasculature. Cellular stress, inflammatory response, and other radiation effects on endothelial cells may affect vascular function. This study was aimed at understanding the effects of space ionizing radiation on the formation and maintenance of capillary-like blood vessels. We used a 3D human vessel model created with human endothelial cells in a gel matrix to assess the effects of low-LET protons and high-LET iron ions. Iron ions were more damaging and caused significant reduction in the length of intact vessels in both developing and mature vessels at a dose of 80 cGy. Protons had no effect on mature vessels up to a dose of 3.2 Gy but did inhibit vessel formation at 80 cGy. Comparison with gamma radiation showed that photons had even less effect, although, as with protons, developing vessels were more sensitive. Apoptosis assays showed that inhibition of vessel development or deterioration of mature vessels was not due to cell death by apoptosis even in the case of iron ions. These are the first data to show the effects of radiation with varying linear energy transfer on a human vessel model. (C) 2011 In Radiation Research Society