• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.49-58
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• 2014

A low-swing differential near-ground signaling (NGS) transceiver for low-power high-speed mobile I/O interface is presented. The proposed transmitter adopts an on-chip regulated programmable-swing voltage-mode driver and a pre-driver with asymmetric rising/falling time. The proposed receiver utilizes a new multiple gain-path differential amplifier with feed-forward capacitors that boost high-frequency gain. Also, the receiver incorporates a new adaptive bias generator to compensate the input common-mode variation due to the variable output swing of the transmitter and to minimize the current mismatch of the receiver's input stage amplifier. The use of the new simple and effective impedance matching techniques applied in the transmitter and receiver results in good signal integrity and high power efficiency. The proposed transceiver designed in a 65-nm CMOS technology achieves a data rate of 13 Gbps/channel and 0.3 pJ/bit (= 0.3 mW/Gbps) high power efficiency over a 10 cm FR4 printed circuit board.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11A
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• pp.1182-1189
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• 2007

Frequency reuse in a cellular wireless communication environment gives rise to a phenomenon of cochannel interference. This paper introduces a power control strategy for OFDM based communication systems operating in such an environment. Among the existing power control schemes, IWF(iterative waterfilling) is known to exhibit relatively good performance. However, it requires feedback of power level and bit allocation information for each subcarrier from a receiver to its associated transmitter, which can lead to a considerable overhead, especially for the case of employing large number of subcarriers. Motivated by this, we present a simplified power control scheme with reduced overhead feedback, which allocates some nonzero identical power to the subcarriers of which channel conditions are above a certain threshold and zero power to the other ones. Computer simulations show that the proposed strategy produces a good approximation to the performance of the IWF in terms of the transmission power level while it requires less overhead feedback.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.25-30
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• 2009

The cooling water circulation pipes had been used to drop the temperature of refractory outside shell of blast furnace by cooling plate or stave type. They were attacked by surrounding CO gas and it was the cause that they were corroded and the water inflow in the refractory due to leakage of water. So, the life of refractory material was shorten and changed for the worse the conditions of blast furnace. The automatic sensing device for water leakage of cooling pipe was developed to check the position of trouble by use the micro-process system when cooling water leak and then CO gas will be inflowed into the cooling pipe at the leakage position. The inflowed CO gas will be detected in the micro-process system and delivered the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave the water leakage part immediately and then deliver the signal to main control room by use the micro-process system and wireless-radio relay station. This system will develop the working condition from manual system to unmanned auto alarm system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1042-1049
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• 2007

Frequency reuse in a cellular wireless communication environment gives rise to a phenomenon of cochannel interference. This paper introduces a power control strategy for OFDM based communication systems operating in such an environment. Among the existing power control schemes, IWF(iterative waterfilling) is known to exhibit relatively good performance. However, it requires feedback of power level and bit allocation information for each subcarrier from a receiver to its associated transmitter, which can lead to a considerable overhead, especially for the case of employing large number of subcarriers. Motivated by this, we present a simplified power control scheme with reduced overhead feedback, which allocates some nonzero identical power to the subcarriers of which channel conditions are above a certain threshold and zero power to the other ones. Computer simulations show that the proposed strategy produces a good approximation to the performance of the IWF in terms of the transmission power level while it requires less overhead feedback.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.17 no.2
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• pp.33-37
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• 2011

Real time control logic of microbial shelf life of a perishable food, seasoned pork meat has been formulated which exploits monitoring of $CO_2$ concentration of the package. The potential of the proposed logic was examined for storage at dynamic temperature conditions. The start of increase in $CO_2$ production rate from the food or rate of package $CO_2$ concentration change was found to coincide with the point of microbial quality limit and could be used as an index of microbial shelf life determination. This also corresponded to lag time of $CO_2$ concentration change or time for the $CO_2$ concentration to reach a certain value. The application potential of the proposed logic was confirmed for a sensor system to measure on real time and transmit the $CO_2$ concentration wireless to the computer system.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.297-297
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• 2010

KSTAR 토카막의 두번째 실험 캠페인 동안 고속파 전자가열 (FWEH)을 위한 ICRF 고주파입사 실험을 실시하였다. 토로이달 자기장은 2 T, 플라즈마 전류는 200-300 kA, 주반경은 1.8 m, 부반경은 0.5 m의 원형 플라즈마가 가열 대상이 되었으며, 네개의 ICRF 안테나 전류띠 가운데 중심부의 두개의 전류띠를 최대 300 kW로 구동하기 위한 운전 주파수는 44.2 MHz가 선택 되었다. 이 주파수는 플라즈마의 모든 영역에서 이온 사이클로트론 공명을 일으키지 않으므로 플라즈마에 흡수되는 대부분의 출력은 전자에게 전달될 것으로 기대되었다. 낮은 고주파-플라즈마 결합으로 인하여 전송선의 최대 고주파 전압이 허용치를 초과하기 때문에 비교적 낮은 최대 출력만이 허용 되었으나, ECE에 의해 관측된 전자의 온도는 국지적으로 최대 150 % 까지 증가하는 것을 확인 할 수 있었다. 낮은 고주파-플라즈마 결합의 첫번째 원인은 FWEH의 효율이 이온을 가열할 때 보다 상대적으로 낮기 때문이다. 플라즈마 내에 이온 사이클로트론 공명층이 형성되면 높은 효율로 고주파를 입사 할 수 있다는 것은 잘 알려진 사실이다. 또다른 원인은 D 형상의 플라즈마에 맞도록 만들어진 안테나와, 원형 플라즈마간의 부조화로 인하여 고속파 차단층이 (Fast Wave Cutt-off Layer) 평균적으로 넓게 형성되기 때문이다. 플라즈마 외곽에 반드시 존재하는 낮은 플라즈마 밀도의 고속파 차단층 내부에서, 중심부로 향하는 고주파의 진폭은 지수함수로 감쇠하므로 가능하면 플라즈마 밀도를 높여 차단층 자체의 폭을 줄이거나, 안테나 전류띠를 플라즈마에 바짝 접근시켜야만 한다. 고주파 진단 장치로는 송출기의 출력과 반사파 측정 장치, 공명루프의 전압 측정 장치가 있는데, 이것들을 이용하여 안테나에 전달되는 출력 및 고주파-플라즈마 결합 효율을 나타내는 플라즈마에 대한 고주파 부하 저항을 구할 수 있다. 측정 결과, 부하 저항의 최소값은 진공시 또는 ICRF만의 방전시의 값 0.25 Ohm 보다 큰 0.5 Ohm을 나타냈으며, 최대값은 플라즈마의 상태에 따라 1 Ohm에서 2 Ohm 사이에서 매우 빠르게 요동하는 것을 확인했다. Mm 파 반사계의 측정에 의하면 플라즈마 언저리의 위치가 약 3 cm 정도의 크기로 요동하는 것으로 나타났는데, 부하 저항과 언저리 위치의 파형이 정확하게 일치하지 않지만 유사한 경향성을 가진 것으로 보인다. 따라서 플라즈마 언저리 위치의 제어를 통하여 가열 효율을 높게 유지할 수 있음을 알 수 있다. 본 발표에서는 실험의 소개와 함께 부하 저항의 관점에서 가열 효율을 높일 방안을 토론하도록 한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.39-46
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• 2015

In this paper, a gas sensor using a modified $90^{\circ}$ hybrid coupler structure with conducting polymer which operates at 2.4 GHz is represented. Conducting polymers are used to the gas sensing material in proposed sensors. The conducting polymer varies its electrical property, such as work function and conductivity corresponding to the certain gas. To verify this variation of electrical property of conducting polymer at microwave frequencies, the conducting polymer is incorporated with the $90^{\circ}$ hybrid coupler structure, and this proposed sensor operates as reflection type variable attenuator and variable phase shifter. The conducting polymer is employed as impedence-variable transmission lines that cause a impedance mismatching between the general transmission line and conducting polymer. The experiment was conducted with 100 ppm ethanol gas at temperature of $28^{\circ}C$ and relative humidity of 85 %. As a result, the amplitude deviation of $S_{21}$ is 0.13 dB and the frequency satisfying ${\angle}S_{21}=360^{\circ}$ is shifted about 2.875 MHz.

• Journal of IKEEE
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• v.23 no.2
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• pp.743-746
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• 2019

In this paper we proposed a new ocean radiation automatic monitoring system. The proposed system has the following characteristics: First, using NaI + PVT mixed detectors, the response speed is fast and precision analysis is possible. Second, the application of temperature compensation algorithm to scintillator-type sensors does not require additional cooling devices and enables stable operation in the changing ocean environment. Third, since cooling system is not needed, electricity consumption is low, and electricity can be supplied reliably by utilizing solar energy, which can be installed at the observation deck of ocean environment. Fourth, using GPS and wireless communications, accurate location information and real-time data transmission function for measurement areas enables immediate warning response in the event of nuclear accidents such as those involving neighboring countries. The results tested by the authorized testing agency to assess the performance of the proposed system were measured in the range of $5{\mu}Sv/h$ to 15mSv/h, which is the highest level in the world, and the accuracy was determined to be ${\pm}8.1%$, making normal operation below the international standard ${\pm}15%$. The internal environmental grade (waterproof) was achieved, and the rate of variation was measured within 5% at operating temperature of $-20^{\circ}C$ to $50^{\circ}C$ and stability was verified. Since the measured value change rate was measured within 10% after the vibration test, it was confirmed that there will be no change in the measured value due to vibration in the ocean environment caused by waves.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.719-729
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• 2017

Recently, the field of agriculture has been gaining a new leap with the integration of ICT technology in agriculture. In particular, smart farms, which incorporate the Internet of Things (IoT) technology in agriculture, are in the spotlight. Smart farm technology collects and analyzes information such as temperature and humidity of the environment where crops are cultivated in real time using sensors to automatically control the devices necessary for harvesting crops in the control device, Environment. Although smart farm technology is paying attention as if it can solve everything, most of the research focuses only on increasing crop yields. This paper focuses on the development of a system architecture that can harvest high quality crops at the optimum stage rather than increase crop yields. In this paper, we have developed an architecture using apple trees as a sample and used the color information and weight information to predict the harvest time of apple trees. The simple board that collects color information and weight information and transmits it to the server side uses Arduino and adopts model-driven development (MDD) as development methodology. We have developed an architecture to provide services to PC users in the form of Web and to provide Smart Phone users with services in the form of hybrid apps. We also developed an architecture that uses beacon technology to provide orchestration information to users in real time.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.119-125
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• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.