隨著無線網路的普及，以及大多數PDA 和手機等行動裝置均具備無線上網的能力，普及運算逐漸成為新型態的行動電腦應用趨勢，其目標為：在任何時間、任何地點、使用任何設備，皆能輕鬆取得資訊且能進行回應。達到該目標的一項重要議題是，在這種經常變動的運算環境裡，如何認知察覺周遭情境的改變，如：使用者目前位置、使用者目前從事的活動、使用者鄰近的人與可用資源等之變化，並根據新的情境主動調適系統與使用者的互動。這個普及運算領域的重要研究方向一般稱之為察覺情境運算。 過去大多數察覺情境之普及運算的研究偏重於對個人的支援，對群組協同合作與互動較為缺乏。因此，本文先探討既有之情境與察覺情境的定義，提出目前察覺情境之群組通訊研究的不足之處。針對不足的地方，我們設計並且實作一個具察覺情境功能之群組通訊系統，以無線存取設備追蹤定位使用者，並利用及維護與行動使用者相關之情境資訊，提供基本之群組通訊服務，同時輔助該使用者與相同群組的成員聯繫與互動。 With the wide spread of wireless networks and universal installation of wireless connectivity firmware in handheld devices, such as PDAs and mobile phones, pervasive computing has become a new trend of mobile computer applications. The goal of pervasive computing is to acquire and respond to information by any device from anywhere at any time. One of the challenging issues to achieve this goal is how to recognize the changes to the environments, like the mobile user''s current location, user''s activities and user''s nearby people and available resources. The system should adapt its behavior to interact with users in such highly dynamic computing environment. This important research agenda in the realm of pervasive computing is referred as context-aware computing. Past researches about context-aware computing focused on supporting individuals and lacked support of collaborations and interactions for groups. Therefore, this thesis begins with the discussion of the definitions of context and context-aware computing, and explains the deficiencies of current context-aware group communication researches. Then we attack these defects, and design and implement a context aware group communication system. This system can track the mobile user''s location by using a Wi-Fi Access Point, provide basic group communications services by utilizing and maintaining his related context information, and help the mobile user to contact and interact with other group members.
