• Journal of Korea Multimedia Society
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• v.18 no.3
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• pp.401-407
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• 2015

In this paper, we propose the method to eliminate EMI (Electro-Magnetic Interference) in ELF (Extremely Low Frequency) band below 2 KHz for extending the gesture-recognition distance of smart TVs to more than 3m using electric potential sensor. First, we measure the electric field generated from the back panel of a TV and propose the effective arrangement of two sets of differential sensors as well as the shielding method using metal fiber. Also, we eliminate the PLN (Power Line Noise) and other noise generated from the TV and sensors as well as surrounding environments using filters. Using the proposed EMI eliminating methods, we evaluate displacement ratio on measured signals according to distance between sensors and a moving hand. Experiment results show that our proposed method can extend the hand-gesture sensing distance using EPS (Electric Potential Sensor) up to more than 3m, which is enough to satisfy applicability of EPS based remote control to Smart TVs.

• Progress in Superconductivity
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• v.8 no.2
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• pp.158-163
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• 2007

YBCO do superconducting quantum interference device (SQUID) magnetometers based on bicrystal junctions have been fabricated for magnetocardiograph (MCG) measurements. We could fabricate YBCO SQUID magnetometers having magnetic field noise of about $20fT/Hz^{1/2}$ at white noise region. We have developed an MCG system employing the high performance SQUID magnetometers. The lightweight MCG system, requiring liquid nitrogen as a coolant, consists of 6-channel SQUID sensors, an adjustable patient bed with sliding motion, and data analyses software. The MCG system could record quite clear MCG signals in a room with moderate magnetic shielding. In normal operation with multi-position MCG measurements, we could obtain clear 48-point mappings of magnetic field map and current source map with high enough signal qualities far clinical trials.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.9
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• pp.791-796
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• 2010

Installing noise barriers is the most common method for reducing the highway traffic noise to the road side residential area. After the report about edge potential concept of a noise barrier, various types of noise reducing devices(NRDs) called "noise reducers" have been suggested for getting more shielding effect on the top of highway noise barriers. But, it has been doubtful about effect of the NRDs in field because there was no appropriate and unified method to estimate the acoustic performance by using field measurement of the NRDs in Korea. In this study, the authors have considered to setup a practical method to test and estimate the acoustic performance of NRDs. For eliminating the noise reduction effect of the NRDs height itself, the source and measuring points are adjusted as highly as the NRDs height. For the frequency weighting in the estimation of the NRDs effect, the highway noise spectra were measured at asphalt and concrete road side and then averaged for a unit spectral parameter.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.182-186
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• 2014

Recently, the use of panoramic radiography has shown a constant increase, and significant research is underway. However, radiation exposure attracts less attention in dental radiography than in other types of radiography. We used an OSLD for measurement of the entrance skin dose in eyeballs and the thyroid region, both of which are not covered by examinations but are included in radiographical regions and are sensitive to radiation, as well as orally in Incheon and reported the results. The entrance skin dose was 0.0282 mSv on average for the oral region, and 0.0259 mSv on average for the eyeball, and 0.0261mSv on average, for thyroid gland. While there is no proper shielding method for the eyeball, a thyroid protector is not used by most hospitals and most hospitals are equipped with an apron and a thyroid protector separately; thus, it is necessary to use an integration of an apron and a thyroid protector and medical device manufacturers need to develop a method for controlling the length of the slit in the slit-type area of radiation occurrence in order to reduce unnecessary exposure.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.365-373
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• 2015

We propose a simple and compact thyristor-based neuron circuit. The thyristor exhibits bi-stable characteristics that can mimic the action potential of the biological neuron, when it is switched between its OFF-state and ON-state with the help of assist circuit. In addition, a method of inter-neuron connection with synaptic devices is proposed, using double current mirror circuit. The circuit utilizes both short-term and long-term plasticity of the synaptic devices by flowing current through them and transferring it to the post-synaptic neuron. The double current mirror circuit is capable of shielding the pre-synaptic neuron from the post synaptic-neuron while transferring the signal through it, maintaining the synaptic conductance unaffected by the change in the input voltage of the post-synaptic neuron.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.486-492
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• 2010

This paper studies an experimental analysis of the impulse noise of K2 rifle when its bullet passes through the large tube(length 1.84m, outer diameter 50cm, glass wool & steel). In experiment, the characteristics of the sound of shooting were different according to the way of shooting; the results of the experiment are given below. First of all, the shooting sound was lower in single-shot shooting, when compared to 3rds burst-shot shooting, difference averaging 2.8dB, 4.0dB at maximum. In short, the difference is minuscule. Secondly, the sound of the K2 rifle was diminished when shot in a tube, ranging from 2.7dB to 15.4dB, averaging 8.2dB. Thirdly, the shooting sound of the K2 rifle was diminished as the insertion depth deepened with formulas given in Fig. 5, 6. Fourthly, basic data for excluding sound of the shooting were presented. Lastly, the characteristics of the shooting sound could be equally used as a basic material for developing marksmanship and sharp-shooting detection device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.63-69
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• 2014

RFIDs have not become widespread as expected partly due to the cost, size, read range, and reliability problems of tags. The success rate of reading must be improved in order for RFIDs to be widely adopted. Quality control of tags is crucial to meet this requirement. In this study, we designed and implemented a high-performance reader used in inspection equipment that conducts prior inspection of tags. To improve performance of the developed reader, the baseband modem and command processor (CP) were designed using H/W logic and implemented with FPGA. The inspection of small pitch inlays was made possible through the antenna shielding device and H/W command processor function. This equipment enables accurate evaluation of performance and identification of tags satisfying a given read range. By contributing to sort out defective tags, the results can ultimately lead to more stable RFID services.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.146-154
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• 1998

Broadband noise with frequency components in the range from several kHz up the tens of MHz is a major obstacle factor in normal operation of the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices such as filter and surge suppressor are used to cut off the noise. But those devices could not disconnected from the power line, so they result in poor common-mode of NCT as well as insulation characteristics as a isolation transformer in addition faraday shielding and proposed analysis model of NCT having tow functions of surge and noise reduction. The simulated and experimental results for the surge suppression characteristics are compared and evaluated for designed protype 1[kVA] NCT.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.335-341
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• 2017

Cyclotron is a device that accelerates positrons or neutrons, and is used as a facility for making radioactive drugs having short half-lives. Such radioactive drugs are used for positron emission tomography (PET), which is a medical apparatus. In order to make radioactive drugs from a cyclotron, a nuclear reaction must occur between accelerated positrons and a target. After the reaction, unncessary neutrons are produced. In the present study, radioactivation generated from the collisions between the concrete shielding wall and the positrons and neutrons produced from the cyclotron is investigated. We tracked radioactivated radioactive isotopes by conducting experiments using FLUKA, a type of Monte Carlo simulation. The properties of the concrete shielding wall were comparatively analyzed using materials containing impurities at ppm level and materials that do not contain impurities. The generated radioactivated nuclear species were comparatively analyzed based on the exposure dose affecting human body as a criterion, through RESRAD-Build. The results of experiments showed that the material containing impurities produced a total of 14 radioactive isotopes, and $^{60}Co$(72.50%), $^{134}Cs$(16.75%), $^{54}Mn$(5.60%), $^{152}Eu$(4.08%), $^{154}Eu$(1.07%) accounted for 99.9% of the total dose according to the analysis having the exposure dose affecting human body as criterion. The $^{60}Co$ nuclear species showed the greatest risk of radiation exposure. The material that did not contain impurities produced a total of five nuclear species. Among the five nuclear species, 54Mn accounted for 99.9% of the exposure dose. There is a possibility that Cobalt can be generated by inducive nuclear reaction of positrons through the radioactivation process of $^{56}Fe$ instead of impurities. However, there was no radioactivation because only few positrons reached the concrete wall. The results of comparative analysis on exposure dose with respect to the presence of impurities indicated that the presence of impurities caused approximately 98% higher exposure dose. From this result, the main cause of radioactivation was identified as the small ppm-level amount of impurities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2624-2628
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• 2011

Exposed dose of a patient was measured by Radiophotoluminescent Glass Rod Detector with a use of a panorama graphic device in dental examination. The effect of exposed dose in optic lens was measured by comparing the different materials of the glasses. Depending on the dental location, the exposed dose distribution was 82.4~2,340uSv. It showed that the maximum difference in dose distribution was over 300%. Thus, when manufacturing the devices, it seemed to require shortening the pre-heat time and additional shielding in order to control the diagnosis and exposed dose. The measurement data of the exposed dose in optic lens was increased 20~75uSv per each test when compared putting on glasses with not wearing. As a result, taking off the glasses is recommended to improve efficiency of the test and minimize the exposed dose during dental panorama graphic examinations.