在機會網路上，傳遞資料遠比一般網路困難。運用行動代理人於機會網路上，
可大幅提升機會網路的功能，其中的行動代理人平台，需要一個代理人的搜尋
機制，方能實現對代理人的控制。本篇論文以「山文誌登山資訊系統」為背景，探討行動代理人在機會網路上的應用。在此登山客追蹤與環境監控系統中，每個登山客都攜帶一個配備有 GPS 功能的小型設備，此設備會在登山客的移動過程中，自動收集位置資訊，並使用短程無線電來和鄰近的登山客交換彼此的資訊。由於行動代理人是附屬於登山客所攜帶的設備上，而且當靠近其他登山客時，才可藉此轉移到另一個設備，故其行動力受制於登山客的移動行為。因登山客行走速率差異不大、所在位置分佈不均，使得行動代理人的轉移極為緩慢且需仰賴不確定的碰面機會，導致行動代理人之搜尋效率極低，無法支援緊急任務。為此，我們提出控制網路的方法，及一個簡單的搜尋演算法，讓搜尋代理人藉此高速網路來快速移動，以提高目標代理人的搜尋效率。在不同的考量及目標下，我們提出幾個控制網路的建置模型，並在證明其為 NP-complete問題後，提出有效的啟發式演算法來解決此控制點選擇問題。 / Transmitting data on an opportunistic network is much more difficult than that on a general network. The communication capability of an opportunistic network can be greatly enhanced via mobile agent functionality. A mobile agent platform demands a search mechanism to locate and control its agents. In this thesis, we investigate the adoption of mobile agent to opportunistic networks using "CenWits" system as reference model. In CenWits system, each hiker carries a GPS enabled sensor node to collect and exchange movement statistics with its fellow hikers using a short range wireless links. Since mobile agents will be attached to the sensor nodes that hikers carry with, mobile agents can hop from one host to another only when two hosts (hikers) meet together such that their mobility is restrained by the moving behavior of hikers. The little difference in walking speed and the uneven distribution of hikers make the hopping of mobile agents extremely slow and opportunistic. As a consequence, the search of mobile agents is slow and inefficient crippling agility of urgent agent functionality. Therefore, we propose to construct a control network using high speed network for search agents to travel in high speed. Under different objectives and constraints, we propose several control point placement models. After proving them to be NP-Complete, we propose few efficient heuristic algorithms to solve the placement problem. We also propose a simple search algorithm for search agents to search target agents quickly by using a control network.
| Identifer | oai:union.ndltd.org:CHENGCHI/G0095753008 |
| Creators | 林怡萱, Lin, Yi Shiuan |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 中文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
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