Effective Node Location Assignment and Connectivity Maintenance for Mobile Video Surveillance Service on Wireless Ad Hoc Networks
Date Issued
2010
Date
2010
Author(s)
Lin, Chia-Ching
Abstract
This thesis develops a rapid and suitable for VLSI implementation algorithm to solve the connection establishment problem of a mobile video surveillance system. When the target is out of the coverage, this algorithm can establish a video connection to cover the target quickly and stream the target’s image to the requesting node. Base on the mathematical model, Initial and Coverage Connection Problem (ICCP), established by Wun-Yan Lyu 2008, we design a solution algorithm to solve this problem for the purpose of fast, good quality and has the potential to implement.
For the unstable transmission quality in wireless networks, the research of 呂文彥 does not address much. He assumes that there is no interference within the network and battery energy of each node can meet requirements of missions. Nevertheless, the real situation is that the energy of the node would decrease continuously to attenuate the transmission strength of packets and then affect qualities of videos. Thus, to develop the mechanism to maintain the completeness of video connection when the quality of transmission channel is not great is also an vital issue.
Based on the Greedy Heuristic and the Branch-and-Bound methodology, this thesis first, by the heuristic step, sets the upper bound of the moving distance of the assigned node to reduce the path combinations that the second part of the algorithm needs to search. Next, the thesis utilizes the Depth First Search of the Branch and Bound methodology to find the shortest path and then designs the Two Stage Greedy Branch and bound Algorithm (TSGBA), which is adapted to be embedded in chips, for solving the ICCP. TSGBA can obtain an assignment result with good quality (averagely 5% inaccuracy to optimal solutions) in a short time period (10seconds/ 10 nodes within networks.)
This thesis also addresses the mechanism for maintaining connections for the issues of unstable transmission channel quality. The main concepts are: (1) the periodic inspection of residual energy in mission nodes and packet receiving strength (2) the definitions of the critical points in two layers for battery energies of nodes and packet receiving strength to identify the activation time (3) The exploitation of the TSGBA to re-solve ICCP for finding substitutive paths. This mechanism would re-assign the locations of nodes to avoid the break off of connections, when the transmission quality is lower than some level in the mission.
As for the implementation, this thesis inherits the interfaces of Wun-Yan Lyu 2008 (the self broadcast system and the commanding mechanism) that were developed via VB.NET 2003TM in the application layer. Using Visual Basic programming language to implement TSGBA as an object and integrate it in the interfaces, this thesis can achieve the automatic solution findings of node location assignments for establishing video coverage connections without optimization tool suites.
Subjects
mobile video surveillance
coverage
command to move
connection
establishment
maintenance
Type
thesis
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