Kyo-Hong Jin

Enhancement of IEEE 802.11 modules in ns-2 and performance evaluation with error rate

Ns-2 is being widely utilized to evaluate the wired and wireless networks on many research activities. The ns-2.33 distribution version includes an extension of IEEE 802.11 module which improves the core functions of 802.11 MAC and PHY protocols. Although this extension version provides well-designed MAC and PHY functions, it has some significant shortcomings in handling packet errors. When a packet error rate, one of the most important performance parameters in wireless network simulations, applies to the extension, a simulation program is interrupted with some fatal errors. Besides, as the packet errors are handled on the PHY layer in this version, MAC layer loses its own right of treating the packet errors. In this paper, we modify the extension version to correct the mentioned problems and verify the behavior of our modified version by simulation work. And also, we perform the ns-2 simulation to investigate the impact of error rate on IEEE 802.11p-based vehicular ad-hoc networks.

Design of the Manufacturing Facility Maintenance Systems Based on Internet of Things

There is a strong movement to utilize sensor data which are collected by IoT devices on manufacturing facility. Especially, using these data, companies which manufactures and sells the manufacturing facility or buyers require a kind of maintenance systems for easily managing their facilities because they want to minimize a suspension of work caused by a breakdown on the facility. From their perspective, the suspension means unnecessary expenditure. Therefore, they want to quickly recognize that the breakdown has occurred and restart the facility as soon as possible by solving the problem. In this paper, we design the reference model for the manufacturing facility maintenance systems. The purpose of this systems is to reduce the losses caused by the breakdown.

Measuring the Greenhouse Gas Emission Reduction and Management System Using Bluetooth Sensor Node

Carbon dioxide is a major cause for which accelerates Global Warming. Therefore several countries are working on the project recommended to use a bicycle instead of the car when you move to the nearby destination in an effort to reduce the emissions of carbon dioxide. In this paper, It was developed to measure the greenhouse gas reduction using Bluetooth Sensor Node by riding a bicycle instead of a car and management system in order to authenticate the riding record. The developed application provides various information such as individual bicycle mileage, greenhouse gas reductions, bicycle riding path, the number of planted ginkgo trees. This proposed system is expected to be helpful to green house gas emission reduction because the usage rate of bicycle will increase if government combine ways to offer people rewards such as pin money or tax breaks for people who take advantage of the bicycle with the project.

A Low-Power 512-Bit EEPROM Design for UHF RFID Tag Chips

In this paper, a design for a low-power 512-bit synchronous EEPROM with flash cells for passive UHF RFID tag chip is presented. Applied are low-power schemes such as dual power supply voltage(VDD=1.5V and VDDP=2.5V), clocked inverter sensing, voltage-up converter, IO interface, and Dickson charge pump using schottky diode. An EEPROM is fabricated with the 0.25μm- EEPROM process. Simulation results show that power dissipations are 8.34μW in the read cycle and 57.7μW in the write cycle, respectively. The layout size is 449.3μm × 480.67μm.