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The Live Video Database Management System (LVDBMS) is a general-purpose framework for managing and processing live video data for surveillance and analytical applications. This system allows for automatic event recognition over a network of live cameras. The user is able to specify a monitoring task by formulating a query describing a spatiotemporal event. This query may be formulated as a combination of logical, spatial, and temporal operators. When the specified event is observed, an action associated with the query is triggered.

Virtual Router Details

To reduce the number of nodes needed in data forwarding and still be able to handle a high mobility environment, we introduce the Virtual Router abstraction in this paper. A virtual router is a logical router that is associated with a particular geographic area. A virtual router comprises one or more physical mobile nodes currently within a geographical region served by the virtual router. Once within the geographical region of the virtual router, those physical nodes can take turns in forwarding data packets. In this environment, data packets are transmitted from a source node to a destination node over a series of virtual routers. There can be two virtual router approaches: Static Virtual Router (SVR) and Dynamic Virtual Router (DVR). In SVR, the virtual routers are predetermined and shared by all communication sessions over time. This scheme requires each mobile node to have a map of the virtual routers, and use a global positioning system (GPS) to determine if the node is within the geographical region of a given router. We present SVR in [1][2]. In this paper, we introduce the DVR approach with the following distinctions: (1) virtual routers are dynamically created for each communication sessions as needed, and deprecated after their use; (2) mobile nodes do not need to have a GPS; and (3) mobile nodes do not need to know whereabouts of the virtual routers.

The advantages of the virtual router approach are as follows:

  • Although the physical nodes may move, the virtual routers do not since they are defined by the geographical region. Due to that stability, a virtual connection comprising the virtual routers is much more robust than a traditional physical connection used in existing MANET designs.
  • Since the forwarding of each data packet is confined to the virtual routers along the communication path, the virtual router approach does not suffer excessive data forwarding.
  • This strategy eliminates the overhead of maintaining clusters.


  1. Y. H. Ho, A. H. Ho, and K. A. Hua, “Connectionless Protocol – A Localized Scheme to Ad Hoc Network.” Proc. of International Journal of Ad Hoc and Ubiquitous Computing (IJAHUC), Vol. 2, Issue 1/2, pp. 21 – 35, 2007. [paper]
  2. Y. H. Ho, A. H. Ho, K. A. Hua, and G. L. Hamza-Lup. “A Connectionless Approach to Mobile Ad hoc Networks,” Proc. of IEEE Symposium on Computers and Communications (ISCC 2004), Vol. 1, pp. 188 – 195. [paper]