Ikki Niwa, Toshihiro Osaragi, Takuya Oki, & Noriaki Hirokawa. (2015). Development of Real Time Synchronous Web Application for Posting and Utilizing Disaster Information. In L. Palen, M. Buscher, T. Comes, & A. Hughes (Eds.), ISCRAM 2015 Conference Proceedings ? 12th International Conference on Information Systems for Crisis Response and Management. Kristiansand, Norway: University of Agder (UiA).
Abstract: In a large earthquake, rescue operations and fire-fighting are obstructed by fire-spreading and street-blockages. Therefore, it is important to quickly collect and utilize disaster information for disaster mitigation. In this paper, firstly, we develop a Web application for posting and viewing information collected by users in real time. Using this system, it is possible not only to easily share disaster information among users but also to apply to damage forecast such as fire-spreading. Next, we demonstrate the usefulness of the Web application by the following evaluation view points: (1) relationship between the access time of emergency vehicles from fire stations to the locations of fires and the ratio of collected information on street-blockage which is assumed to be collected with this system; (2) reciprocating time between a server and a client which is dependent on the number of users and band limitation after the occurrence of a disaster.
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Takuya Oki. (2018). Possibility of Using Tweets to Detect Crowd Congestion: A Case Study Using Tweets just before/after the Great East Japan Earthquake. In Kees Boersma, & Brian Tomaszeski (Eds.), ISCRAM 2018 Conference Proceedings – 15th International Conference on Information Systems for Crisis Response and Management (pp. 584–596). Rochester, NY (USA): Rochester Institute of Technology.
Abstract: During large earthquakes, it is critical to safely guide evacuation efforts and to prevent accidents caused by congestion. In this paper, we focus on detecting the degree of crowd congestion following an earthquake based on information posted to Social Networking Services (SNSs). This research uses text data posted to Twitter just before/after the occurrence of the Great East Japan Earthquake (11 March 2011 at 02:46 PM JST). First, we extract co-occurring place names, proper nouns, and time-series information from tweets about congestion in the Tokyo metropolitan area (TMA). Next, using these extracted data, we analyze the frequency and spatiotemporal characteristics of these tweets. Finally, we identify expressions that describe the degree of crowd congestion and discuss methods to quantify these expressions based on a questionnaire survey and tweets that contain a photograph.
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Takuya Oki, & Toshihiro Osaragi. (2017). Evaluation of Conversion to Quake-Resistant Buildings in Terms of Wide-Area Evacuation and Fire-Brigade Accessibility. In eds Aurélie Montarnal Matthieu Lauras Chihab Hanachi F. B. Tina Comes (Ed.), Proceedings of the 14th International Conference on Information Systems for Crisis Response And Management (pp. 25–41). Albi, France: Iscram.
Abstract: It is important to evaluate the effects of improving the disaster vulnerability of towns by using various indices related to human damage. In this paper, we focus on conversion of low quake-resistant old buildings. Firstly, we construct a simulation model, which describes property damage (such as building-collapse and street-blockage), wide-area evacuation behavior, and fire-brigade's activities immediately after a large earthquake occurs. Next, using the simulation model, we estimate the travel time required for evacuation, the number of evacuees trapped on streets (or in blocks), and the access time of fire-brigades to fires in case that the ratio of quake-resistant buildings in the area increases to a certain value. Based on the results, we discuss the effects by converting old buildings into quake-resistant ones on reducing the difficulty in wide-area evacuation and improving the accessibility of fire-brigades in multiple study areas with different characteristics.
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Takuya Oki, & Toshihiro Osaragi. (2016). Wide-area Evacuation Difficulty in Densely-built Wooden Residential Areas. In A. Tapia, P. Antunes, V.A. Bañuls, K. Moore, & J. Porto (Eds.), ISCRAM 2016 Conference Proceedings ? 13th International Conference on Information Systems for Crisis Response and Management. Rio de Janeiro, Brasil: Federal University of Rio de Janeiro.
Abstract: In aiming to decrease the number of casualties and people with difficulty in wide-area evacuations due to a large earthquake, it is highly important to visualize and quantify the potential danger in residential areas. In this paper, we construct a multi-agent simulation model, which describes property damage (such as building-collapse, the spread of fire and blocking of streets) and people?s evacuation behavior after an earthquake occurring. Using this simulation model, we quantify the wide-area evacuation difficulty in densely-built wooden residential areas, and evaluate the past project to improve buildings and streets based on this indicator. Furthermore, we demonstrate the effects of adding new evacuation routes between two intersections of streets with narrow width and long distance. Through these case studies, the effectiveness of our simulation model on urban disaster mitigation planning is shown.
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Takuya Tsuchiya, Toshihiro Osaragi, & Takuya Oki. (2015). Influence of Information-Hearsay on Wide-Area Evacuation at a Large Earthquake. In L. Palen, M. Buscher, T. Comes, & A. Hughes (Eds.), ISCRAM 2015 Conference Proceedings ? 12th International Conference on Information Systems for Crisis Response and Management. Kristiansand, Norway: University of Agder (UiA).
Abstract: In order to evacuate smoothly and safely at a large earthquake, it is important to obtain the information on property damages (such as street-blockage and fire) and on evacuation areas by hearsay, guidance and bulletin boards. In this paper, we construct a model, which describes wide-area evacuation, information-hearsay among evacuees and guidance behavior. Using this model, we evaluate the influence of information-hearsay on wide-area evacuation in terms of the evacuation time and the risk on evacuation routes. Simulation results demonstrate that the locational information of evacuation areas and damages is the most helpful for people who are unfamiliar with an area. In addition, we discuss the effective and efficient methods of evacuation guidance. The results show that the guides contribute to reducing the evacuation time and the risk on evacuation routes of evacuees, and sharing information among guides enables more efficient and safer evacuation / guidance.
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Toshihiro Osaragi, Koji Ogino, Noriaki Hirokawa, & Takuya Oki. (2022). Severity of Crowding at Evacuation Shelters after a Major Earthquake. In Rob Grace, & Hossein Baharmand (Eds.), ISCRAM 2022 Conference Proceedings – 19th International Conference on Information Systems for Crisis Response and Management (pp. 22–43). Tarbes, France.
Abstract: A number of residents are presumed to evacuate to shelters after a large earthquake. However, the congestion of evacuation shelters has not been enough discussed. In this paper, we propose an evacuation behavior model, which includes sub-models on building damage, water-supply failure, power failure, fire damage, and elevator stall. Using the model estimated using the survey data of the past earthquakes, we discuss the congestion of evacuation shelters under the assumption of Tokyo Bay northern earthquake. Finally, we discuss improvement of water pipes for earthquake resistance to reduce the congestion degree of evacuation shelters, which varies according to regional vulnerability.
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