Optimum Neighbors for Resource-Constrained Mobile Ad Hoc Networks

This paper presents an investigation on the optimum number of neighbors for mobile ad hoc networks (MANETs). The MANETs are self-configuring and self-organizing networks. In such a network, energyconstrained mobile nodes share limited bandwidth to send their packets to the destinations. The mobile nodes have a limited transmission range and they rely on their neighbors to deliver their packets. Hence, the mobile nodes must be associated with the required (i.e., optimum) number of neighbors. As the number of neighbors is varied, a trade-off exists between the network connectivity and available bandwidth per mobile node. To investigate this issue, we consider Dynamic Source Routing (DSR) as the routing protocol and IEEE 802.11 as the MAC layer protocol in this work. We consider both static and dynamic scenarios in this work. We simulated the ad hoc networks via network simulator (NS-2) and the simulation results show that there exists an optimum number of neighbors for the static case. We also show that mobility has a grave impact on the performance of the MANETs in terms of network throughput, end-to-end delay, energy consumption, and packet loss. Hence, we need to increase the number of neighbors under mobility conditions. However, there is no global optimum number of neighbors for the mobility case.

Development of a White-Cane-Extension to Detect Automatic Doors

The majority visually impaired persons are using a white cane to move within their environment. They avoid to collision the obstacles by detecting objects when swinging white cane touches them. An automatic door is opened when it detects the person comes to it by the sensor, for example, infrared sensor. This kind of automatic doors are very useful because we need not touch the doors in order to open them. However, for majority visually impaired persons, it is difficult to detected automatic doors because they detect the object by touching. In this paper, we propose the detection method which tells the existence of automatic doors to the visually impaired person. The device is consisted of an infrared sensor and a vibration motor. The infrared sensor is put on the tip of the white cane and the vibration motor is put on close to the hand. And when it detects the infrared signal, the vibration motor runs. Then the visually impaired persons can through the automatic door in safety without any cares