• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.753-758
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• 2009

This paper is proposed the hardware structure and signal processing method of the RF-Tag based on heart sound to develop the mobile biomedical information device for the u-healthcare system. The RF-Tag in this study is consisted of a skin temperature sensor, a dynamic microphone for heart sound detection, Bluetooth communication to transmute healthcare data, and pulse period detection algorithm with adaptive gain controller. We experimented to evaluate performance of the RF-Tag in noisy environments. In addition, the RF-Tag has shown the good performance in the results of experiment. If the proposed methods in this study apply to design the u-healthcare device, we will be able to get the exact health data on real time in mobile environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.41-44
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• 2004

A RFID(Radio Frequency IDentification) system Is a kind of Radio Frequency Communication System and a branch of Automatic Data Collection System. The RFID System is composed of RF Tag(or Transponder) and RFID Reader(controller). This paper deal with Wireless communications that acquired RF Tag ID by RFID reader, and then target system will transmit Tag ID to RFID Server through the internet using Wireless LAN. The RFID system of Todays are commonly used by a wired RFID system. In this system uses commonly used Wireless LAN, and then we can connect the internet if we have a AP(Wireless Lan Access Point). Internet connection can make a transmission of RF Tag ID, and can make a reception of returning data that are images or information.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.35-42
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• 2003

We have studied DC energy conversion of RF card by wireless communication. In order to attain an objective, it used the system which is a Rectenna. The main purpose of energy conversion system is the operation of the circuits at RF-ID system. The proposed RF-ID system is a lot classified with the reader and tag. Reader is a kind of the base station role supporting RF energy. And priority tag convert RF energy from the reader it was delivered with a wireless to DC energy. The energy which is converted like Tag. It transmits to the reader characteristic ID of each card. The tag is mainly divided into rectifier, power module, memory and controller. The FRAM maintains the data like a ROM in no-power situation. And the advantage is a low power element compared with other EEPROM. There are two considerations, when RF energy is converted into DC source by wireless. One is energy amount supported from the reader, the other is high power efficiency. This paper presents a study of simulation and experiments on the RF-DC conversion circuit in tag by the power efficiency concentrated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.356-357
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• 2007

In this paper, we developed an integrated miniaturized device which acquires and transmits the signal of ECG an interested heartbeat and body's temperature and humidity. Using an amplifier circuit on the electrodes and the radio frequency transmission, the developed system dispenses with the use of cables among the electrodes, amplifier, and the post processing system. The sensor signals are transmitted to the RF-wireless terminal that was developed using the micro controller Aduc812, LCD, RF-module (frequency 424MHz, 9600-bps). In results, the developed system improves not only the signal-to-noise ration in dynamic ECG & and body's temperature and humidity measurement, but also the user convenience.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.457-461
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• 2002

This paper describes a development of a robot working in hazard environment. The developed robot consists of robot controller with vision system and host PC program. The robot and camera can move with 2 degree of freedom by independent remote controlling a user friendly designed joystick. An environment is recognized by the vision system and ultra sonic sensors. The visual image and command data translated through 900MHz and 447MHz RF controller, respectively. To show the validity of the developed system, operations of the robot in the field area were illustrated.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.217-219
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• 2004

In recent years, the smart card is wifely applied for wireless communication, tracking, transportation logistics, diagnostic monitoring, access control and security. RF-ID system is universally applicable. Passive RF-ID system consists from reader and passive tag. The reader transmits energy and simple information to a tag by wireless and the power from the reader is transformed for controller, FRAM and Bluetooth module. in this paper, an analysis and design of smart card for the transmission of the car movement data is presented.

• Proceedings of the KIEE Conference
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• summer
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• pp.1445-1447
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• 2004

In recent years, the smart card is widely applied for wireless communication, tracking, transportation logistics, diagnostic monitoring, access control and security. RF-ID system is universally applicable. Passive RF-ID system consists of reader and passive tag. The reader transmits energy and simple information to a tag by wireless and the power from the reader is transformed for controller, FRAM and Bluetooth module. In this paper, proposed for the improvement of wireless power transmission and demonstrated the propriety through experiments in several conditions.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.89-92
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• 2000

A wire communication module for PLC controller was developed. This system consists of RF module interface part, RS232 serial communication control part, LED display part and control S/W with GUI interface. RF communication frequency is controlled by PLL controlling and communication rate is also controlled as 1200 and 4800 bps. Communication and control status are displayed on LED. As a S/W part, graphic user interface on Window 95 O.S. was developed. To show the validity of the developed system, severial communication and control of PLC system were experemented.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.255-258
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• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.223-228
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• 2018

In this paper the water sensor using a coaxial cavity resonator is designed and manufactured. The water sensor which can sense water drop linearly has been constructed with voltage controlled oscillator(VCO), coaxial cavity resonator, RF switch, RF detector, A/D converter, DAC and micro controller. The operating frequency range of the designed water sensor is from 2.5GHz to 3.2GHz and the input voltage and current source are 24[V/DC] and 1[A]. The designed sensor circuit includes VCO, RF switch, RF detector which varies the frequency characteristics of the devices in the high frequency of 3GHz. And so we should correct the error of the frequency characteristics of those devices in the sensor circuit. To do this, we make the reference path which switches the signals to the RF detector directly without sending it to the resonator. According to the result of simulation and measurement, we can see that there is 0-50MHz difference between simulated resonator frequency and manufactured resonator frequency.