Vol.5 No.2 2012

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Research paper : Information sharing platform to assist rescue activities in huge disasters (I. Noda)−119−Synthesiology - English edition Vol.5 No.2 (2012) When designing the mechanism for sharing and utilizing the disaster information, particularly in designing the information system, the difference in the lifecycles of disaster and information technology must be carefully considered.Most disasters occur irregularly and at long time intervals. For example, earthquakes of a scale that incurs societal damages occur at several decades to several hundred years time span, or in some cases in a thousand years for certain regions. The wind and flood damages occur relatively frequently but not regularly every year. Generally speaking, disasters cause unexpectedly large damages because they occur infrequently. In other words, the disaster information system will not operate most of the time, except during disaster drills or during those “infrequent moments.” The disaster information system of the local government is updated at five to ten year intervals, and the latest technologies and functions are introduced during the updates. At the same time, old technologies and functions are gradually removed. Therefore, most systems and technologies may be used only a few times or finish their jobs without ever being deployed in actual disasters.The difference in the time scale of lifecycles is overcome by the continuity of the data. Compared to frequent updates of systems, data is accumulated over a long time, and its lifespan is long. Particularly, value of data recorded in usable format may not become obsolete so quickly. As mentioned earlier, while the information systems of local governments may be updated by five to ten year intervals, it is important how the data is carried over during such updates. Therefore, in designing the disaster information sharing system, it is important to focus on the reusability and accumulation of the data over decades or a hundred years.3.2 Data-centered case-by-case system linkageThe data-centered concept is important in the viewpoint of case-by-case system linkages. Responses to disasters are done by many organizations, and the disaster information system must be operated across such organizations. Designing and implementing a monolithic information system where multiple organizations are involved is very difficult in reality. The realistic solution will be for each organization to design and construct an information system individually as a subsystem, and to link them. In that case, there are two design policies of linkages: function-centered or data-centered.One example of the function-centered system linkages is the web service linkage mechanism using the web services description language (WSDL) or universal description, discovery and integration (UDDI). In the web service linkages, individual servers realize and provide various functions, and a high-level service is achieved by combining them. This is excellent in that flexible response to diverse requirements can be realized easily, and is an effective concept for rescue activities where diverse responses are demanded. However, each server must be designed and implemented with consideration of “linkages,” and the local governments must prepare the necessary functions.The data-centered system linkages are represented by the blackboard model. In the blackboard model, each subsystem provides data to the common area (blackboard) or retrieves data from the common area to achieve linkages among the subsystems. In this concept, the subsystem can be operated as long as data are provided to the blackboard, and the “linkages” among the subsystems do not have to be the prime consideration. On the other hand, it is difficult to combine the functions closely or flexibility, and it is not suitable for achieving multiple, high functions.Considering the fact that the disaster information system is utilized by the local governments throughout Japan, the mechanism of system linkages should be data-centered rather than function-centered. Japan spreads out from south to north, and there are various types of disasters. There are regions that suffer from heavy snow and other regions that must watch out constantly for floods. The functions required vary greatly and the combinations are complex. Also, the disaster prevention system of the local governments and the relevant organizations are not uniform, and the ways of building the subsystem differ. Therefore, the important points are which subsystems have the necessary functions and data and how to supplement the items that are short. While the supplementation of lacking functions is difficult to solve instantly, the lacking data is not too hard to supplement if the deterioration of dynamic property and accuracy can be tolerated.Moreover, according to the hearings[5] of the local governments of the regions affected by the Great East Japan Earthquake, it has become apparent that many local governments had to alter existing disaster prevention plans because various unexpected conditions occurred. While the disaster prevention plans will certainly be reviewed thoroughly by the local governments after the Great East Japan Earthquake, it is necessary to maintain flexibility in the response, anticipating that the unexpected will happen. The information system must be designed as a system where the functions can be rearranged after an event. The key to allow quick rearrangement after an event is the simple linkage mechanism by data mediation. A case study will be presented with a demonstration system in the next chapter.The data-centered system linkage concept is similar to the concept of the open source program development. In The Cathedral and the Bazaar (http://www.catb.org/%7Eesr/writings/cathedral-bazaar/; Japanese translation available in http://cruel.org/freeware/

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