Sungjin Ahn

A 2 S: Automated Agriculture System based on WSN

This paper describes the results of real deployment of A S which consists of WSN(Wireless Sensor Network) to monitor and control the environments and a management sub-system to manage the WSN and provide various and convenient services to consumers with hand-held devices such as a PDA living a farming village. The WSN were deployed in greenhouses with melon and cabbage in Dongbu Handong Seed Research Center. A S was used to monitor the growing process of them and control the environment of the greenhouses. We acquired valuable experiences and ideas from this real deployment and operation of A S and believe that they can be useful in consumer electronics field such as home network as well as automated agriculture field. .

Proactive context-aware sensor networks

We propose a novel context detection mechanism in Wireless Sensor Networks, called PROCON. In PROCON, context decisions are made in a distributed way, by cooperation of nodes connected through a context overlay on the network. As a result, the sensor network can deliver context level information, not low level sensing data, directly to proper actuators. Moreover, PROCON achieves highly efficient energy consumption compared to the existing centralized context detection mechanism. The analysis and simulation results show that the proposed mechanism outperforms the existing centralized mechanism in average energy consumption, capability of mitigating congestion to a base station, context service lifetime, and reliability.

Wireless Sensor Networks for Cultural Property Protection

Wireless sensor network technology has been proven to have a strong impact on our daily life from many real applications. In this paper wireless sensor networks for cultural property protection are introduced. We deployed wireless sensor networks in Bul-guk-sa Temple, which is one of the most important UNESCO cultural property sites in Korea. This paper presents our wireless sensor network system for monitoring and protecting cultural property from the aspect of application design to network system management.

Multi-hop Network Re-programming Modelfor Wireless Sensor Networks

Network re-programming in wireless sensor networks is an essential facility, especially in practice, for deploying and maintaining highly dynamic sensor nodes. This paper proposes an efficient way to update whole binary image based on layered architecture with multi-hop network protocol. The layered architecture utilizes 3 different memories including flash, RAM and EEPROM. The network dissemination protocol is based on hierarchical routing and support practical considerations such as sleep/wake-up mechanism for energy saving.

Power-Aware position vector routing for wireless sensor networks

We propose PPVR, a power-aware position vector routing protocol for wireless sensor networks. PPVR is an energy efficient geographical routing protocol that improves existing geographic routing protocols in two ways. First, in the forwarding phase, PPVR reduces the transmission energy by passing packets through a relay node called a power-aware node. Second, PPVR provides an efficient void node avoidance scheme that mitigates the cases forwarding packets to a wrong path so that higher route discovery success rate is achieved. The simulation results shows that the PPVR outperforms existing geographic routing protocols including GPSR and GEAR, in terms of the energy consumption and the successful delivery rate.

Mosaic Localization for Wireless Sensor Networks

Unlike relative location information, obtaining absolute location in multi-hop way usually requires anchor nodes to periodically flood the network. However, due to the limited resource of sensor nodes, this causes significant reduction in sensor nodes lifetime. In this paper, we propose a localization system called Mosaic. As the name implies, by matching pieces of the puzzle, which plays similar role with the relative locations, Mosaic provides absolute location with significantly reduced packet transmissions. Our simulation results show significantly reduced packet transmissions of Mosaic while not losing accuracy compared with flooding-based localization systems.