• Journal of Biosystems Engineering
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• v.37 no.6
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• pp.352-358
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• 2012

Purpose: The inexpensive black box system was developed to acquire and save driving information, to give the slope information, and to transmit SOS and theft signal. Method: The device consists of a main micro controller to acquire and save data, a GPS sensor module, a CDMA module, a touch LCD module, a RF (Radio Frequency) ID module, a SD (Secure Digital) card module, an emergency electric power source, a theftproof circuit, and a sensing device. The sensing device consists of a 8 bit micro controller, a accelerometer to detect impulse, two slope sensors to detect roll and pitch angle and a circuit to detect operation of 6 lighting devices. Results: Test results are as follows: 1) a tractor can be start up only with an electronic key (password or RFID card), 2) theft signal was transmitted when a tractor moved without an electronic key, 3) SOS was transmitted at conditions that rollover or crash happened. 4) 5 more than per 1s data are recorded at 5 minute intervals as new file name in SD card. Conclusions: This system can be used to save travelling record, reduce accident, prevent theft and rescue life in the accidents.

• Journal of Sensor Science and Technology
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• v.12 no.2
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• pp.88-94
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• 2003

Electromyogram (EMG) is the bioelectric signal induced by motor nerves. Analyzing EMG with the movement produced by muscle contraction, we can provide input commands to a computer as a man-machine interface as well as can evaluate the patient's motional abnormality. In this paper, we developed an integrated miniaturized device which acquires and transmits the surface EMG of an interested muscle. Developed system measures $60{\times}40{\times}25mm$, weighs 100g. Using an amplifier circuitry 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 (personal computer). The wiring used in conventional systems can be obstacle for natural motion and source of motion artifacts. In results, the developed system improves not only the signal-to-noise ration in dynamic EMG measurement, but also the user convenience. We propose a new human-computer interface as well as a dynamic EMG measurement system as a possible application of the developed system.

• Progress in Superconductivity and Cryogenics
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• v.16 no.3
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• pp.21-25
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• 2014

As wireless power transfer (WPT) technology using strongly coupled electromagnetic resonators is a recently explored technique to realize the large power delivery and storage without any cable or wire, this technique is required for diffusion of electric vehicles (EVs) since it makes possible a convenient charging system. Typically, since the normal conducting coils are used as a transmitting coil in the CPT system, there is limited to deliver the large power promptly in the contactless EV charging system. From this reason, we proposed the combination CPT technology with HTS transmitting antenna, it is called as, superconducting contactless power transfer for EV (SUWPT4EV) system. As the HTS coil has an enough current density, it can deliver a mass amount of electric energy in spite of a small scale antenna. The SUCPT4EV system has been expected as a noble option to improve the transfer efficiency of large electric power. Such a system consists of two resonator coils; HTS transmitting antenna (Tx) coil and normal conducting receiver (Rx) coil. Especially, the impedance matching for each resonator is a sensitive and plays an important role to improve transfer efficiency as well as delivery distance. In this study, we examined the improvement of transmission efficiency and properties for HTS and copper antennas, respectively, within 45 cm distance. Thus, we obtained improved transfer efficiency with HTS antenna over 15% compared with copper antenna. In addition, we achieved effective impedance matching conditions between HTS antenna and copper receiver at radio frequency (RF) power of 370 kHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.131-137
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• 2010

UMSN (Ubiquitous Medical Sensor Network) is being used in u-Healthcare system of various medical facilities to identify objects and get information from sensors in real-time. RFID using radio frequency determines objects using Reader, which reads Tags attached to patients. However, there is a security vulnerability wherein Tag send its ID to illegal Reader because Tags always response to Readers request regarding of its Tag ID. In this paper, we propose Tag ID Classification Scheme to reduce Back-end Server traffic that caused by requests to authenticate between Readers and Tags that are attached to medical devices, patients, and sensors; To reduce security threats like eavesdropping and spoofing that sometimes occurred during authentication procedure. The proposed scheme specifies the patient category as a group based on patients Tag ID string. Only allowed Reader can perform authentication procedure with Back-end Server. As a result, we can reduce Back-end Server traffic and security threats.

• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.203-207
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• 2009

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of ITO thin films intended for use as anode contacts in OLED (organic light emitting diodes) devices. These ITO thin films are deposited by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar+$O_2$, and Ar+$H_2$) at $300{^{\circ}C}$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0.5 sccm to 5 sccm and from 0.01 sccm to 0.25 sccm, respectively. The intensity of the (400) peak in the ITO thin films increased with increasing $O_2$, flow rate whilst the (400) peak was nearly invisible in an atmosphere of Ar+$H_2$. The electrical resistivity of the ITO thin films increased with increasing $O_2$ flow rate, whereas the electrical resistivity decreased sharply under an Ar+$H_2$ atmosphere and was nearly similar regardless of the $H_2$ flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier mobility rather than the charge carrier concentration. All the films showed an average transmittance of over 80% in the visible range. The OLED device was fabricated with different ITO substrates made with the configuration of ITO/$\alpha$-NPD/DPVB/$Alq_3$/LiF/Al in order to elucidate the performance of the ITO substrate. Current density and luminance of OLED devices with ITO thin films deposited in Ar+$H_2$ ambient gas is the highest among all the ITO thin films.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.818-823
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• 2016

Millimeter wave (mm-wave) communication systems provide high data rates owing to the large bandwidths available at mm-wave frequencies. Recently, analogue and digital combined beamforming, namely "hybrid beamforming" has drawn attentions owing to its ability to realize the required link margins in mm-wave systems. Taking into account the radio frequency (RF) hardware limitations, such as the analogue phase shifter gain constraint and the low resolution of the phase controller, we introduce an uplink hybrid beamforming system that includes discrete Fourier transform (DFT) based "fixed" analogue beamforming. We adopt a zero-forcing (ZF) multiple-input multiple-output (MIMO) equalizer to eliminate the uplink inter-user interferences. Moreover, to improve the sum-rate performances, we propose a transmit beam selection algorithm which makes the uplink effective channels, i.e., the beamformed channels, become near orthogonal. The effectiveness of the proposed beam selection algorithm was verified through numerical simulations.

• Elastomers and Composites
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• v.36 no.2
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• pp.94-101
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• 2001

In this work, the effect of NE plasma treatment generated by radio-frequency was investigated in acid-base surface values, ion adsorption characteristics, and surface free energies of carbon blacks. As the results, it was clearly found that the obvious improvement of the treatment is in the London dispersive component (${\gamma}s^L$) of surface free energy of carbon blacks. Also both electron-acceptor ( ${\gamma}s^+$) and -donor (${\gamma}s^-$) parameters for the specific component (${\gamma}s^{sp}$) were also increased with increasing the treatment time, resulting in increasing the surface functional groups of the carbon blacks studied, together with a consequence of the increases of acidic and basic surface functional groups, ion exchange, zeta potential, and ion mobility.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.6
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• pp.50-57
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• 2009

In this paper, a deep-heating stimulation system and protocol were designed to substitute the heat effect of moxibustion. Moxibustion is used to increase immunity and cure disease. But, it is difficult to control power of heat stimulation. A designed deep-heating stimulation system using Radio-Frequency(RF) is easy to control power of heat stimulation. Also, the stimulation protocol for substitution of the heat effect of moxibustion is proposed. Core temperature was applied to infrared camera, thermometer, and infrared sensor, and then was compared with that of moxibustion. The proposed system showed that it is more effective than moxibustion in transferring heat effect in such a deep part. Also, it shows the possibility of usefulness of deep-heating stimulation system and heat stimulation protocol.

• Journal of the Korean Vacuum Society
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• v.19 no.4
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• pp.287-292
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• 2010

We have investigated the effects of oxygen flow ratios on the structural, morphological, and optical properties of AlN thin films grown by using radio-frequency reactive magnetron sputtering. The AlN thin films were deposited at $300^{\circ}C$ of substrate temperature, and the reactive gas were supplied with both nitrogen and oxygen. The oxygen flow ratio was varied by controlling the amount of oxygen with respect to the total mixed gases, 0%, 10%, 15%, 20%, 25%, and 30%. The structural, morphological, and optical properties of the deposited AlN thin films were examined by using X-ray diffractometer, scanning electron microscopy, and ultraviolet-visible spectrophotometer. The AlN thin film grown at 10% of oxygen flow ratio indicated an average transmittance of 91.3% in the wavelength range of 350~1,100 nm and an optical band gap of 4.30 eV. The experimental results suggest that AlN thin films can be deposited optionally by varying the oxygen flow ratio.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.57-66
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• 2007

1974. 8. 15 SeoulMetro, beginning with the first electric railway established at six cities, so it is managing mass transportation of traffic. Especially, in case of seoul, It is managing that from one to eight lines, 286.9km, 265 stations have installed and now it is carrying about 5.5million of passengers everyday, and 2,000million passengers a year. So accident is increasing from the station every year. For this measure, SeoulMetro prepares safety fence for passengers crash but, as suicides or people who watch the accident took place, for at the bottom of passengers crash protection, PSD installing is needed. Even though, PSD is managing ATO section but, in controlling SeoulMetro, one to four lines sections are (ATS, ATC)section. Between as ATS, ATC section, ATO section, subway gate and PSD must have opened and crossed always at the time. And the interlock control corrosion protection gate, managing skills with installation, method, using in history, apply to 10rail cars one train sets, and maximum applying 2224% sections of passengers congested that consideration is to be needed. So 2004, SeoulMetro improved technology and basie design of PSD at ATS section. Based on this, from 2005.4 to 2006.6, using subway 2lines per 12stations set the model installation(full type 11stations, half type 1station) After installing in case of success, it is going about to suggest that effective analysis and hereafter subject.