在情境感知的系統之中，位置是一個十分重要的資訊。許多服務必須根據使用者的所在位置才能夠被完整的提供。而無線網路的訊號可以被用來估計測量出使用者的位置。我們提供了一個室內的無線網路定位系統，是利用倒傳遞類神經網路、模擬退火法以及最小封閉圓的技術完成的。倒傳遞類神經網路以及模擬退火法可以提供完善的類神經網路架構來估計使用者的位置，而最小封閉圓的技術可以使定位的結果更為精確，也因此本系統是一個適合的室內定位系統。

Location is one of the contextual variables most relevant to the design of context-aware computing systems. These application need to know the physical location of users in order to provide information relevant to their position. Radiofrequency signals received by mobile devices can be measured to obtain signal strength. These signals can be used to estimate the approximate location of a user. We present a WLAN indoor location determination approach using BPN+SA and enclosing circle. The BPN+SA can provide suitable results of estimation and make the better network architectures and parameters which result in a better classification. The enclosing circle can make the results more precisely. So the proposed approach can be considered as a compatible location estimation system.

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