Hyung-Bong Lee

Interactive remote control of legacy home appliances through a virtually wired sensor network

With the advance of wireless communications technology, home automation based on home networks has regained attention. This paper proposes a wireless network protocol and a control device, which make it possible to control legacy home appliances in an interactive way. The proposed wireless network protocol provides a bidirectional communication channel between a gateway and control devices. The control device hooked up to the wireless network controls a legacy home appliance requested by a user using IR signals and returns the result of the control action as a digested image so that the user can determine if the control operation has been conducted properly. The feasibility of the network protocol and control device is demonstrated by an experiment in which a wireless network is constructed using the proposed network protocol and TVs and air conditioners are controlled via the wireless network and the result is fed back to the user.

A Lightweight Lap Time Measurement System for Alpine Ski Sport Using a TDMA-Based Linear Wireless Sensor Network

In Alpine ski sport, traditional lap time measurement systems record a skiers departure and arrival using time-of-day timers through wires, which is not cost effective in unofficial or training games. This paper develops a lightweight lap time measurement system using a wireless sensor network, which employs a practical TDMA-based linear wireless sensor network protocol for multihop communications in long strap-shaped environments where sensor nodes are linearly deployed. We evaluate the performance of this protocol through the implementation and deployment of the lap time measurement system. The experimental results show that the proposed protocol transmits data at a success rate of 99.66% and maintains the time synchronization errors between two adjacent nodes within 183 μs without using any other time synchronization protocols. In an experimental deployment for a 1.5 km ski slope covered by 31 nodes, the system provides lap time measurements with a measurement error of 1.255 ms, which satisfies the official measurement error of 5.0 ms.

Design and Implementation of a Wireless Sensor Network Protocol for a Smart Power Outlet System

This paper deals with the design and implementation of wireless sensor network protocol for smart power outlet system capable of fire detection, power monitoring, standby power cutoff, and home automation. The proposed protocol integrates both the CSMA and the TDMA protocols for low power consumption and good scalability. A prototype smart power outlet system employing the proposed protocol and a simple home automation network including the power outlet system have been implemented for evaluating the feasibility of the proposed protocol The result shows that the proposed protocol allows the power outlet system to be scalable with high power efficiency.

Implementation of a DB-Based Virtual File System for Lightweight IoT Clouds

ABSTRACT IoT(Internet of Things) is a concept of connected internet pursuing direct access to devices or sensors in fused environment of personal, industrial and public area. In IoT environment, it is possible to access realtime data, and the data format and topology of devices are diverse. Also, there are bidirectional communications between users and devices to control actuators in IoT. In this point, IoT is different from the conventional internet in which data are produced by human desktops and gathered in server systems by way of one-sided simple internet communications. For the cloud or portal service of IoT, there should be a file management framework supporting systematic naming service and unified data access interface encompassing the variety of IoT things. This paper implements a DB-based virtual file system maintaining attributes of IoT things in a UNIX-styled file system view. Users who logged in the virtual shell are able to explore IoT things by navigating the virtual file system, and able to access IoT things directly via UNIX-styled file I⋅O APIs. The implemented virtual file system is lightweight and flexible because it maintains only directory structure and descriptors for the distributed IoT things. The result of a test for the virtual shell primitives such as mkdir() or chdir() shows the smooth functionality of the virtual file system, Also, the exploring performance of the file system is better than that of Window file system in case of adopting a simple directory cache mechanism.Keywords:IoT(Internet of Things), Cloud Service, VFS(Virtual File System), DB-Based File System