• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.348-352
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• 2022

Hydrogen gas (H₂) which is odorless, colorless is attracting attention as a renewable energy source in varions applications but its leakage can lead to disastrous disasters, such as inflammable, explosive, and narcotic disasters at high concentrations. Therefore, it is necessary to develop H₂ gas sensor with high performance. In this paper, we confirmed that H₂ gas detection ability of SnO₂ based H₂ gas sensor along with thermal treatment effect of SnO₂. Proposed SnO₂ based H₂ gas sensor is fabricated by MEMS technologies such as photolithgraphy, sputtering and lift-off process, etc. Deposited SnO₂ thin films are thermally treated in various thermal treatement temperature in range of 500-900 ℃ and their H₂ gas detection ability is estimatied by measuring output current of H₂ gas sensor. Based on experimental results, fabricated H₂ gas sensor with SnO₂ thin film which is thermally treated at 700 ℃ has a superior H₂ gas detection ability, and it can be expected to utilize at the practical applications.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.337-342
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• 2022

Hydrogen (H₂) gas is widely preferred for use as a renewable energy source owing to its characteristics such as environmental friendliness and a high energy density. However, H₂ can easily reverse or explode due to minor external factors. Therefore, H₂ gas monitoring is crucial, especially when the H₂ concentration is close to the lower explosive limit. In this study, metal oxide materials and their p-n heterojunctions were synthesized by a hydrothermal-assisted dip-coating method. The synthesized thin films were used as sensing materials for H₂ gas. When the H₂ concentration was varied, all metal oxide materials exhibited different gas sensitivities. The performance of the metal oxide gas sensor was analyzed to identify parameters that could improve the performance, such as the choice of the metal oxide material, effect of the p-n heterojunctions, and operating temperature conditions of the gas sensor. The experimental results demonstrated that a CuO/ZnO gas sensor with a p-n heterojunction exhibited a high sensitivity and fast response time (134.9% and 8 s, respectively) to 5% H₂ gas at an operating temperature of 300℃.

• The Magazine of the IEIE
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• v.24 no.4
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• pp.424-424
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• 1997

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.186-189
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• 2005

An embedded monitoring and control system which can be controlled and monitored with web, was implemented in this paper. The principal data which should be controlled are the present temperature and pH of a fish farm. The input signals are from temperature sensors and pH sensors. The input data are digital which are A/D converted every constant time, and the results are stored to the database. The converted data are displayed on a large electric signboard at the fish-farm. This system was designed that supervisors can control the system and watch the real situation of the fish-farm at remote places.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1187-1190
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• 2004

This paper presents a traveler guidance system that offers 3D street information such as road types, signal light systems, street trees, buildings, etc. We consider 5x4 road system of Gangnam(in Seoul, Korea) as a test area and reflect the traveler's car-driving situation. A web server is constructed to serve traveler's driving path by switching 3D animation scenes automatically. To do batch processing of geometric data for the 3D graphical streets construction, we have extracted major street information from present GIS database and created new GIS file formats (SMF files), which contain data sessions for links, nodes, and facilities. With these files, we can render 3D navigation scenes. A number of vector calculations were performed for the geometrical consistence and texture-mapping method was used for the realistic scene generation. Finally, we have verified the effectiveness of the service by operating a test scenario. We have checked whether traveler's 2D path and 3D navigation are exactly reported after setting specific departure and destination. This system offers us well awareness of streets and takes useful role of traveler guidance.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.312-319
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• 2015

The grinding and furbishing process as the finishing process for molds include the works such as the grinding, buffing, lapping and polishing among others. A finishing tool unit is applied to this finishing process for the burr, lapping, polishing and others of molds. A finishing tool unit can carry out the flexible machining, depending on the machining allowance for objects to be cut on the basis of the instrumental driving mechanism which enables the up, down, left and right floating, which is applied in link with the dedicated cutters and robot machining systems. This study selected the shape to increase the rotatory force of an impeller when air is discharged during the driving of a finishing tool unit, and reflected it to the impeller designing. In addition, the study analyzed each flow velocity and pressure distribution per air pressurization value and finally analyzed the rotating torque to suggest the optimal conditions in designing impellers.

• Design & Manufacturing
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• v.9 no.1
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• pp.9-13
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• 2015

The HEV/EV Traction Motor Core manufacturing technology is a core component of Traction Motor Core is a key technology for the manufacture of eco-friendly automotive industry is essential for the competitiveness of the country must obtain the technology. This study was performed to develop a Rotor Core of the HEV/EV Traction Motor using the first time in Korea multi-gate BMC injection molding technique. Executed by the experiment of this study are as follows. Study 1: Developed a multi-gate BMC injection mold for the magnet fixed to the Rotor Core. Study 2: Developed a production implementation and manufacturing technology of the Rotor Core. In this study, the develop products and manufacturing technologies implemented by the BMC injection mold development for Magnet fixed to the Rotor Core and the results are discussed.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.230-237
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• 2006

본 논문은 스포츠 방송의 몰입감 증대를 위한 진동촉감 제시 시스템 및 장치를 제안하며, 촉감 정보를 효과적으로 전달하기 위한 촉감제시 방법론 및 제어 알고리즘을 제안한다. 최근 디지털 컨텐츠의 전달에 있어 오감을 통한 정보 전달의 관심이 증대됨에 따라, 대중을 대상으로 다양한 정보를 전달하는 디지털 매체에서의 시청각과 더불어 촉감 제시의 역할과 중요성이 증대되었다. 따라서 본 논문에서는 실시간으로 동적인 현장 상황을 실감 있게 전달하는 스포츠 방송에서의 햅틱 효과와 역할 그리고 가능한 시나리오를 정의하고, 진동촉감 제시 장비를 설계하여 촉감 정보 표현에 대한 기초 연구를 수행하였다. 또한 제안된 촉감을 이용한 스포츠 방송 시나리오 중 축구 방송을 기반으로 사용자 촉감 인지 실험을 수행하였으며, 실험 결과를 바탕으로 축구 방송 시스템을 구축하여 실감방송 전시회 시연을 통해 진동촉감 시스템 및 촉감 제시 방법론을 검증하였다. 촉감이 인간의 오감 중 시청각 다음으로 정보를 인지하는 중요한 감각 체계인 만큼 많은 양의 정보를 대중에게 전달하는 방송 시스템에서 시청각과 더불어 효과적인 정보 전달 체계로써 기여할 것이라고 여겨진다.

• Proceedings of the KSRS Conference
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• v.1
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• pp.398-401
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• 2006

Dual channel Radiometer for Earth and Atmospheric Monitoring (DREAM) is the main payload on Science and Technology SATellite-2 (STSAT-2) of Korea. DREAM is two-channel microwave radiometer with linear polarization, and operating at center frequencies of 23.8 GHz and 37 GHz. An equation for DREAM calibration is derived which accounts for losses and re-radiation in the microwave components of the radiometer due to physical temperature. This paper describes the radiometric calibration equation to get antenna temperature ($T_A$) from the measured output data. At lower altitude, the measured deep space temperature is contaminated by middle atmosphere and earth radiation. In this paper, we presented the detail mathematical formulation to find the altitude up to which cold source brightness temperature is not affected by earth and middle atmosphere radiation. The DREAMPFM data is used to calculate the performance parameters (linearity, sensitivity, dynamic range, and etc.) of the system.

• Journal of the Korean Solar Energy Society
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• v.32 no.2
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• pp.87-94
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• 2012

In this study, we found a relationship between wind shear exponent, ${\alpha}$, and a few factors such as the wind speed, $V$, ruggedness index($RIX$), and the Weibull shape parameter, $k$ of sites in complex terrain in Korea. Wind shear exponents in main wind directions were calculated using wind speed data measured for one year from various heights of eleven meteorological masts in Gangwon province. It was found from the analysis that the reciprocal of the wind shear exponent can be expressed by an exponentially decaying function with respect to a multiple of $V$, $RIX$ and $k$. This result is considered useful to be used to characterize wind characteristics of specific sites in complex terrain in Korea with limited information.