• Analytical Science and Technology
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• v.11 no.1
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• pp.1-7
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• 1998

This study focuses on developing a controlling and analyzing software for the portable atomic emission spectrometer equipped with an electrothermal vaporizer(ETV) that can perform the in-situ trace analysis of heavy metal ions dissolved in water. The software works well for a notebook PC and it is exclusively developed for the real time analysis with a line filter and a photomultiplier light detector. The program is designed to operate under Windows 95 environment and either Korean or English can be used as a main language. The Delphi 2.0 language software is mainly used for programing. The program is designed to make a calibration curve and the system users can get the analytical data in a short time. And a final report can be generated without having difficulties. This software can be easily modified for other analytical atomic spectrometers.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.373-373
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• 2010

광촉매능을 갖는 $TiO_2$는 국내외적으로 많은 연구가 진행되고 있다. 빛의 조사로 발생하는 다양한 물리 화학적 촉매특성이 환경정화 뿐만 아니라 및 에너지 흡수차단 기능도 갖고 있어 최근 주목을 받고 있다. 응용분야로 초친수성 유리제품, 필터, 살균기능의 의료용 부품소재, 고효율 수소생산 및 태양전지 등에 활용성이 커서 친환경에너지 소재로 각광을 받고 있다. 본 연구에서는 초친수성 자동차의 사이드미러 개발을 위해 유리표면에 초친수성 $TiO_2$를 코팅하 고 그의 특성을 평가하였다. 특히, 이종밴드갭을 갖는 복합구조 $TiO_2/Cr_2O_3$/Cr 박막을 스퍼터링법으로 증착하여 중간층인 $Cr_2O_3$의 역할을 고찰하였다. 제조된 박막의 결정구조는 thin film형 X-선회절기(XRD)를 사용하여 분석하였으며, 박막의 표면 미세구조는 FE-SEM(Field Emission Scanning Electron Microscope)와 AFM(Atomic Force Microscope)으로, 화학구조는 XPS(X-ray Photoelectron Spectroscope)로 분석하였다. 친수성 평가는 실온 분위기에서 접촉각 측정기(Topcon-UVR2)를 사용하여 평가 하였으며 이때 조사되는 UV는 파장이 365nm이다. $Cr_2O_3$(비정질)/Cr박막위에 제조된 $TiO_2$ 박막은 균일한 anatase-$TiO_2$가 성장했으나, Cr, $Cr_2O_3$(결정질)박막위에 제조 된 $TiO_2$ 박막은 anatase상과 rulile상이 혼합된 형태로 성장하였다. $TiO_2$/Cr, $TiO_2/Cr_2O_3$(비정질)/Cr, $TiO_2/Cr_2O_3$(결정질)/Cr박막은 UV조사 1시간 만에 $10^{\circ}$ 이하의 초친수성을 나타내었다. 이종 밴드갭을 갖는 $TiO_2/Cr_2O_3$(비정질)/Cr박막은 40시간까지 친수성을 유지하는 결과를 나타냈다.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.145-150
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• 2021

In order to continuously perform quarantine in public places, it is not easy to secure manpower, but using self-driving-based robots can solve problems caused by manpower. Self-driving-based quarantine robots can continuously prevent the spread of harmful viruses and diseases in public institutions and hospitals without additional manpower. The location of the autonomous driving function was estimated by applying the Pinnacle filter algorithm, and the UV sterilization system and chlorine dioxide injection system were applied for quarantine. The driving time is more than 3 hours and the position error is 0.5m.Soon, the stop-avoidance function was operated at 95% and the obstacle detection distance was 1.5 m, and the automatic charge recovery was charged by moving to the charging cradle at the remaining 10% of the battery capacity. As a result of quarantine with an unmanned quarantine system, UV sterilization is 99% and chlorine dioxide is sterilized more than 95%, which can contribute to reducing enormous social costs.

• Journal of Digital Convergence
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• v.17 no.8
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• pp.95-104
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• 2019

Recently, software education has been emphasized as a key element of the fourth industrial revolution. Many universities are strengthening the software education for all students according to the needs of the times. The use of online content is an effective way to introduce SW education for all students. However, the provision of uniform online contents has limitations in that it does not consider individual characteristics(major, sw interest, comprehension, interests, etc.) of students. In this study, we propose a recommendation method that utilizes the directional similarity between contents in the boolean view history data environment. We propose a new item-based recommendation formula that uses the confidence value of association rule analysis as the similarity level and apply it to the data of domestic paid contents site. Experimental results show that the recommendation accuracy is improved than when using the traditional collaborative recommendation using cosine or jaccard for similarity measurements.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1255-1261
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• 2020

Currently, the spread of mobile devices is gradually increasing. Accordingly, various techniques using images or photos are actively being researched. However, image data generates noise for complex reasons, and the accuracy of image processing increases according to the performance of removing noise. Therefore, noise reduction is one of the essential steps. Salt and pepper noise is a typical impulse noise in the image, and various studies are being conducted to remove the noise. However, existing algorithms have poor noise rejection performance in high frequency areas, and average filters have blurring. Therefore, in this paper, we propose an algorithm that effectively removes salt and pepper noise in the high frequency region as well as the low frequency region using entropy. For objective and accurate judgment of proposed algorithms, MSE and PSNR were used to compare and analyze existing algorithms.

• Textile Coloration and Finishing
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• v.34 no.1
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• pp.20-26
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• 2022

Centrifugal spinning is an emerging technique for fabricating micro-to-nano-fibers in recent years. To obtain fibers with the desired size and morphology, it is necessary to configure and optimize the parameters used in centrifugal spinning. In this study, it was controlled by changing the solution's concentration (7.5, 10, and 12.5 wt.%) and disk's rotational velocity (6,000, 8,000, and 10,000 rpm) to prepare centrifugal spun nano-filter. The morphological property, air permeability, and dust collection efficiency of the PVA/PP bi-layer nanoweb prepared by centrifugal spun PVA on the PP micron nonwoven substrate are studied using a field emission scanning electron microscope, an air permeability tester, and a filter tester equipment, and the analysis results indicate that it is suitable as a nano-filter when the concentration of PVA solution is 10 wt.% and the rotational velocity of the disk is 8,000 rpm. The resultant reduced diameter and uniform fibers also proved that an excellent dust collection efficiency filter could be made.

• Journal of Internet of Things and Convergence
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• v.8 no.5
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• pp.33-39
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• 2022

A storage device used in the mobile computing field should have low power, light weight, durability, etc., and should be able to effectively store and manage large-capacity data generated by users. NAND flash memory is mainly used as a storage device in the field of mobile computing. Due to the structural characteristics of NAND flash memory, it is impossible to overwrite in place when a data update request is made, so it can be solved by accurately separating requests that frequently request data update and requests that do not, and storing and managing them in each block. The classification method for such a data update request is called a hot data identification method, and various studies have been conducted at present. This paper continuously records the occurrence of data update requests using a counting filter for more accurate hot data validation, and also verifies hot data by considering how often the requested update requests occur during a specific time.

• Clean Technology
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• v.18 no.4
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• pp.379-389
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• 2012

Environmental issues are being paid more attention due to income growth, urban overcrowding, and population growth in Korea. Among the various environmental problems, odor damage is the one of the serious factors. To take example for food waste combination treatment in Su-young wastewater treatment plant in Busan, many complaints occurred because this plant locate around residential areas. The purpose of this work is not only to analyze odorous elements and their contributions but also to evaluate odor quotient (OQ), sum of odor quotient (SOQ), and treatment efficiency of bio-filter. The results of dilution sensory test of complex odor, grinder, leachate, hopper indicated higher order complex odors happen in July and August. The main odorous elements consisted of hydrogen sulfide, ammonia, methly mercaptan and acetaldehyde, which were analyzed by instrumental detection method, and methyl mercaptan was exceeded over 3,571 times of threshold. In addition, result of contribution of odor was methyl mercaptan (49.95 to 59.08%), hydrogen sulfide (20.43 to 29.27%), trimethylamine (8.82 to 13.42%) and acetaldehyde (9.17 to 11.35%). Other facilities were compared with the contribution of the odor using OQ and SOQ during the process. Sulfur compounds, acetaldehyde, and trimethylamine are high contribution of odor using OQ as well as odor intensity of grinding process is highest. As a result, sulfur compounds (e.g., methyl mercaptan and hydrogen sulfide) are highest for OQ and SOQ of grinding process is highest as 7,067. The removal efficiency of deodorization equipment was more than 90.00% in ammonia and amines, but the average efficiency of sulfur compounds was 53.51%. Thus, this facility is more higher contribution of acetaldehyde and trimethylamine than other treatment facilities. And food waste treatment in environmental area needs to consider appropriate capacity and refers to other bio-filter operating conditions.

• Clean Technology
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• v.12 no.3
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• pp.165-170
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• 2006

When ammonia ($NH_3$) and hydrogen sulfide ($H_2S$) in binary mixture gases were supplied to a biofilter packed with biomedia made of polyurethane, PVA, and worm cast. No odor gases were detected on the outlet of the biofilter when $NH_3$ and $H_2S$ were separately supplied to the biofilter at space velocity(SV) of $50h^{-1}$ until inlet $NH_3$ concentration was increased up to 300 ppmv and inlet $H_2S$ to 428 ppmv. While, inlet $NH_3$ concentration maintained at 50 ppmv, inlet $H_2S$ concentration increased from 1 to 489 ppmv, and the removal efficiency of each gas was investigated. After that, $NH_3$ concentration increased step by step such as 80, 100, 200, 300, 400 and 500 ppmv. $H_2S$ concentration increased gradually when $NH_3$ concentration was set up at each condition. Under each condition, removal efficiency of $NH_3$ and $H_2S$ gas was investigated by analysing the gases sampled from the inlet and outlet of the biofilter. When binary gases were supplied to the biofilter and inlet $NH_3$ concentration was increased from 50 to 300 ppmv, elimination capacity of $NH_3$ increase linearly as inlet loading increased to $11.14g\;N{\cdot}m^{-3}{\cdot}h^{-1}$. However, as inlet $NH_3$ concentration increased over 300 ppmv, both removal efficiency and elimination capacity decreased while inlet loading increased. $H_2S$ removal efficiency was not affected seriously by the simultaneous supply of $NH_3$ when maximum inlet loading of $H_2S$ was under $40.27S{\cdot}m^{-3}{\cdot}h^{-1}$ and maximum inlet loading of $NH_3$ was under $15.25N{\cdot}m^{-3}{\cdot}h^{-1}$.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.131.1-131.1
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• 2010

This study was conducted for engineering optimization for the gasification process which is the key factor for success of Taean IGCC gasification plant which has been driven forward under the government support in order to expand to supply new and renewable energy and diminish the burden of the responsibility for the reduction of the green house gas emission. The gasification process consists of coal milling and drying, pressurization and feeding, gasification, quenching and HP syngas cooling, slag removal system, dry flyash removal system, wet scrubbing system, and primary water treatment system. The configuration optimization is essential for the high efficiency and the cost saving. For this purpose, it was designed to have syngas cooler to recover the sensible heat as much as possible from the hot syngas produced from the gasifier which is the dry-feeding and entrained bed slagging type and also applied with the oxygen combustion and the first stage cylindrical upward gas flow. The pressure condition inside of the gasifier is around 40~45Mpg and the temperature condition is up to $1500{\sim}1700^{\circ}C$. It was designed for about 70% out of fly ash to be drained out throughout the quenching water in the bottom part of the gasifier as a type of molten slag flowing down on the membrane wall and finally become a byproduct over the slag removal system. The flyash removal system to capture solid particulates is applied with HPHT ceramic candle filter to stand up against the high pressure and temperature. When it comes to the residual tiny particles after the flyash removal system, wet scurbbing system is applied to finally clean up the solids. The washed-up syngas through the wet scrubber will keep around $130{\sim}135^{\circ}C$, 40~42Mpg and 250 ppmv of hydrochloric acid(HCl) and hydrofluoric acid(HF) at maximum and it is turned over to the gas treatment system for removing toxic gases out of the syngas to comply with the conditions requested from the gas turbine. The result of this study will be utilized to the detailed engineering, procurement and manufacturing of equipments, and construction for the Taean IGCC plant and furthermore it is the baseline technology applicable for the poly-generation such as coal gasification(SNG) and liquefaction(CTL) to reinforce national energy security and create new business models.