Tanaka K, Atarashi H, Yamaguchi I, Watanabe H, Yamamoto R, Ohe K
Department of Planning, Information and Management, The University of Tokyo Hospital, Tokyo, Japan.
Methods Inf Med. 2012;51(3):221-8. doi: 10.3414/ME10-01-0002. Epub 2011 Mar 21.
In medical institutions, unauthorized access points and terminals obstruct the stable operation of a large-scale wireless local area network (LAN) system. By establishing a real-time monitoring method to detect such unauthorized wireless devices, we can improve the efficiency of security management.
We detected unauthorized wireless devices by using a centralized wireless LAN system and a location detection system at 370 access points at the University of Tokyo Hospital. By storing the detected radio signal strength and location information in a database, we evaluated the risk level from the detection history. We also evaluated the location detection performance in our hospital ward using Wi-Fi tags.
The presence of electric waves outside the hospital and those emitted from portable game machines with wireless communication capability was confirmed from the detection result. The location detection performance showed an error margin of approximately 4 m in detection accuracy and approximately 5% in false detection. Therefore, it was effective to consider the radio signal strength as both an index of likelihood at the detection location and an index for the level of risk.
We determined the location of wireless devices with high accuracy by filtering the detection results on the basis of radio signal strength and detection history. Results of this study showed that it would be effective to use the developed location database containing radio signal strength and detection history for security management of wireless LAN systems and more general-purpose location detection applications.
在医疗机构中，未经授权的接入点和终端会妨碍大规模无线局域网（LAN）系统的稳定运行。通过建立一种实时监测方法来检测此类未经授权的无线设备，我们可以提高安全管理效率。
我们在东京大学医院的370个接入点使用集中式无线局域网系统和位置检测系统来检测未经授权的无线设备。通过将检测到的无线电信号强度和位置信息存储在数据库中，我们根据检测历史评估风险级别。我们还使用Wi-Fi标签评估了我们医院病房内的位置检测性能。
从检测结果中确认了医院外部的电波以及具有无线通信功能的便携式游戏机发出的电波。位置检测性能在检测精度方面显示出约4米的误差范围，在误检测方面约为5%。因此，将无线电信号强度既作为检测位置可能性的指标又作为风险水平的指标是有效的。
我们通过基于无线电信号强度和检测历史对检测结果进行过滤，高精度地确定了无线设备的位置。本研究结果表明，使用包含无线电信号强度和检测历史的已开发位置数据库用于无线局域网系统的安全管理以及更通用的位置检测应用将是有效的。
