| Landslides refer to geological hazards which are triggered by failure of slopes due to the drive of gravity. Most countries in the world have to suffer great loss caused by landslides for its wide range of occurrence. Studies have been done long ago to decrease the losss from it happening. It is found that landslides occur in certain patterns and the relationships between landslides and other natural phenomena such as rains and earthquakes are made certain. Hence, different early warning systems have been built to minimize harms caused by landslides but they fail to work satisfactorily. Landslides still happen in large quantities.China is mountainous and this makes it prone to more landslides. Thus, it's significant, in the spirit of harmonious development, to study and strengthen the construction of early warning systems of landslides in mountainous areas to reduce harm of landslides.Geological hazard evaluation and early warning systems have been constructed to prevent and reduce life and property loss. Early warning system contains different levels of sub-systems to evaluate geological hazard which, under the leadership of national, provincial and municipal government, focus on districts, roads, railways and mines which are vulnerable to geological hazards. It looks that these systems form a top-down mechanism. Nevertheless, lack of good communication among them gives rise to poor information flow and impossibility of sharing necessary information. Hence, these sub-systems are changed into "information islands". Common are the problems existing in these systems—less precise early warnings, narrow source of basic information data and insufficient public participation etc. Therefore, they can't be applied to preventing geological hazards in mountainous areas.Research on early warning of landslides involves both natural science and social science and its application is a complex process of information processing and transmission among experts, governments and the public. In other words, three different categories are involved—technology, organization and society. Hence, the following needs must be satisfied, namely, need for comprehensive multidisciplinary study, need to ensure fluent information flow among the three above-mentioned categories, need to offer quick and convenient early warning service, the last but the utmost important one—need to enhance accuracy of early warnings and decision-making by governments.Enhancing accuracy of early warnings begins with broadening sources of early warning information and improving ability to deal with and integrating all kinds of supervising information. Real-time supervision on geological hazard bodies and mass monitoring and preventing ensures a relatively accurate probability of hazard occurrence. Mass monitoring and preventing serves as the most effective measure to prevent hazards in mountainous areas and hence information got this way should be an important source. But current early warning systems lack efficient way to cope with these data and therefore to informationize mass monitoring and prevent becomes a blind spot.Moreover, an open early warning system for landslides is to be constructed with the assistance of rapidly developing network technology. Thus a new complex early warning system is to be applied to multi-disciplinery research and multi-source of information can be ensured. Characteristics of this new system are as following:being service-oriented to offer uniform interface for getting information and service deployment to actualize the integration of information and service; being open to guarantee ability to get and process data and back up various kinds of methods and facilities to get spacial information; multi-scale spatio-temporal data integration to support heterogenous early warning information; combination of network and spatial information technology to collect and process original information and transmit warnings; distributed information processing to guarantee synergistic processing of mass information by multiple computers; continuity, inheritance and compatibility arising from integration of the current systems into early warning systems of geological hazards to protect users' investments; heterogeneous systems interoperability to ensure the uniform of information.The following achievements have been made in this paper with the guidance of the above-mentioned.First, the system is capable of collecting and processing information of real-time supervision on geological hazard bodies and information of mass monitoring and preventing. Standards for information sharing are unified and software to collect and process such information has been developed. Furthermore, this system translates collected information into early warning information on a certain subject. This improves the current situation in mountainous areas—lacking early warning information on landslides.Secondly, the system is service-oriented so that basic data can be shared. OpenGIS is employed to issue information focusing on spatial expression such as environmental factors and Sensor Web to issue supervision information focusing on space and time. An attempt is made to apply Grid Sensors and its standards to special information which focuses on space, time and scale at the same time. These tools are convenient and serve as standard and hence guarantee the sharing of basic data in open early warning systems.Thirdly, valuation unit of 1km*1km and information model are used to count the degree to which the information offered by three environmental factors which are regarded as the most influential by traditional susceptibility evaluation systems contributes to Kunming landslide susceptibility evaluation. Traditional evaluation systems are less liable because Kunming is a mountainous area. Fractal cluster distribution is characterized by its simplicity, liability and convenient automatic updates.Fourthly, comprehensive early warning evaluation integrates multi-sensor data to unify all special early warning information such as information on susceptibility evaluation and weather to give early warnings. All the early warnings are classified into three categories (including 5 grades), namely, no warning (grade 1 and 2), warning (grade 3,4,5) and indefinable warning. D-S evidence is used to integrate special early warnings, which enables government to collect and cope with early warning information on landslides and make comprehensive, scientific and objective decisions.Fifthly, PPGIS deals with feedbacks from the public on early warning information and WorldWind, an open-source desktop application, is used to deploy Web services to solve problems with current PPGIS in dealing with three-dimensional information. Thus the public can recognize geological environment and early warning information so as to participate in prevention and control of landslides.A conceptual framework of early warning system for landslides has been worked out and the service-oriented construction has been employed to actualize its basic design and prototypes, which will eventually eliminate "information islands".In all, early warning system research, an interdisciplinery research, involves both natural science and social science. Early warning of hazards is still difficult to overcome, let alone to avoid all the potential landslide hazards. Therefore, an interface has been constructed to share information on landslides and multi-disciplinery research so as to seek, in practice, appropriate means to realize the ultimate purpose—to recognize and prevent natural hazards.
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