Abstract
The peer-to-peer (P2P) paradigm has become very popular for storing and sharing information. In most P2P systems, peers are connected by means of a limited range of uniform networks, leading to issues when some connected peers are isolated from the others. In order to address such issues, isolated peers rely on devices with long-range networks to relay their messages. However, since long-range devices can move freely, the set of connected peers may lose their connection. Hence, it is important not only to identify, but also to maximise the area known as the safe region (SR) where a long-range device can move freely while still maintaining connection with its peers. This paper illustrates an innovative and generic monitoring framework that addresses the issues related to frequent query location updating using a systematic approach. In our approach, we propose to apply the Reverse Nearest Neighbourhood (RNNH) concept in a P2P environment to efficiently identify and maximise the irregularly shaped area of the SR up to four times for the potential movement of the long-range devices. It was found that there is no need for costly re- computation when the query is retained within the SR. Monte-Carlo simulation was performed to calculate the area of the SR by weighing in shape irregularity. Experimental results demonstrate the effectiveness and efficiency of our approach.
Highlights
The growing importance of location-based services has led to a new range of real-time services such as location-based social networking that uses GPS to locate users and allows them to broadcast their locations and share information via their mobile devices
We introduce the concept of safe region (SR) for moving query point that keeps the reverse nearest neighbourhood (RNNH) result unchanged
2) AN EFFICIENT ALGORITHM In order to overcome the issue associated with the naïve RNNH query processing algorithm, we propose an R-tree based algorithm to achieve better performance
Summary
The growing importance of location-based services has led to a new range of real-time services such as location-based social networking that uses GPS to locate users and allows them to broadcast their locations and share information via their mobile devices. In this kind of natural disaster, local people are disconnected from the centralized base station and communication between people in one neighbourhood can be achieved via Bluetooth or WiFi (short-range device). In order to manage such disasters, the rescuer must have an SR within which he can move freely in order to make and maintain contact without losing any connection with the neighbourhoods This scenario demonstrates how two types of communication, namely short-range and long-rang communications, in RNNH-based P2P network environments, can assist the affected residents to maintain contact with other residents and with rescuers during a natural disaster. The NNH query is denoted by NNH (q, d, m, P)
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