Jeongho Son

Determination of aggregation point using fermat’s point in wireless sensor networks

We propose a method for determining where to aggregate data from sensor nodes using Fermat’s point to save energy in wireless sensor networks. Unlike most aggregation schemes, our method does not need to construct any tree for aggregation of data. Simulation results show that Fermat’s point can be the most effective aggregation point in terms of energy efficiency and thus the network lifetime.

A Decentralized Hierarchical Aggregation Scheme Using Fermat Points in Wireless Sensor Networks

The energy cost for transmission is more expensive than receiving or sensing cost. In this paper, we propose a decentralized aggregation scheme using the Fermat points to save energy for transmitting redundant low-rate data on many-to-one flows in wireless sensor networks. It can reduce the number of transmissions needed to deliver from each source to the sink. Simulation results show that our scheme is better than the GIT (Greedy Incremental Tree) scheme in terms of the number of transmissions and network lifetime.

A limited flooding scheme for query delivery in wireless sensor networks

In query-driven sensor networks, query is generally disseminated to the whole sensor. When the query needs information on a specific area, it is unnecessary for the query to be flooded over the entire network. In this paper, we propose a query delivery scheme which does not flood the query over the entire area but only to a restricted area. Also, our scheme also offers fault tolerance capability in order to prolong the network lifetime and to provide reliability for query transmissions. A performance evaluation shows that the total energy consumption can be significantly reduced and the sensor network lifetime can be prolonged by our scheme.

In-network processing for wireless sensor networks with multiple sinks and sources

Energy consumption is one of the most crucial issues in wireless sensor networks since sensor nodes are commonly battery-driven. Recently, several aggregation methods have been proposed to save energy by reducing the number of transmissions from source to the sink. They assumed a single sink for aggregation of data. In this paper, we propose an aggregation scheme for wireless sensor networks with multiple sinks. In our scheme, each node caches the gradient information collected from its local neighbors to determine the aggregation point for merging data to be delivered to multiple sinks. The experimental results show that our scheme can reduce the number of transmissions and thus save the energy more than the greedy incremental tree scheme and the shortest path scheme.

An energy efficient method for tracking mobile ubiquitous robots using wireless sensor network

In general, it requires lots of complicated and expensive processing functions to find the exact location of a mobile target. For example, Ubiquitous Robotic Companion (URC) system should be equipped with powerful resources or be given an aid from the external servers to find its location for itself. Sensor network that consists of inexpensive low-power sensors can provide an efficient solution to find the exact location of such a mobile target at a low price. In such applications, if all sensor nodes have to always wake up to find location of the mobile robot, we have to pay a lot of waste of resources such as battery power and channel utilization. In this paper, we propose a cheap and energy efficient location tracking method of a mobile robot by minimizing the number of sensor nodes participating in the task of target tracking.

A MAC protocol using separate wakeup slots for sensor network

This paper presents a MAC protocol which uses separate wakeup slots for each sensor node in sensor networks. Most MAC protocols proposed for sensor network are inefficient under heavy traffic loads, in particular in high density network topology because of frequent collisions and long sleep latency. In this paper, we suggest a MAC protocol in which each node has a different wakeup schedule in the same duty cycle, and it joins the competition only for its own short wakeup slot when the receiver is ready to receive its data. Simulation results indicate that our scheme can reduce energy consumption and minimize idle listening which increases the power efficiency.

A MAC protocol to reduce sleep latency and collisions in wireless sensor network

This paper presents a MAC protocol which uses separate wakeup slots for each sensor node in sensor networks. Most MAC protocols proposed for sensor network are inefficient under heavy traffic loads, in particular in high density network topology because of frequent collisions and long sleep latency. In this paper, we suggest a MAC protocol in which each node has a different wakeup schedule in the same duty cycle, and it joins the competition only for its own short wakeup slot when the receiver is ready to receive its data. Simulation results indicate that our scheme can reduce energy consumption and minimize idle listening which increases the power efficiency.