• Environmental Engineering Research
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• 제23권1호
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• pp.1-9
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• 2018

The degradation of methylene blue (MB) in an aqueous solution by nano-metallic particles (NMPs) was studied to evaluate the possibility of applying NMPs to remove MB from the wastewater. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to characterize the synthesized NMPs before and after the reaction. The effects of the NMP dosage, the initial pH, the initial concentration of MB and the amount of $H_2O_2$ on the MB degradation outcomes were studied. The highest removal rate of MB was achieved to be 100% with an initial MB concentration of 5 mg/L, followed by 99.6% with an initial concentration of 10 mg/L under the following treatment conditions: dose of NMP of 0.15 g/L, concentration of $H_2O_2-100mM$ and a temperature of $25^{\circ}C$. The SEM analysis revealed that the nano particles were not spherical in shape. FTIR spectra shows occurrence of metal oxides on the surfaces of the NMPs. The XPS analyses results represent that Fe, Zn, N, Ca, C and O were occurred on the surfaces of the NMPs. The degradation of MB was suitable for the pseudo-first-order kinetics.

• 방송공학회논문지
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• 제22권6호
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• pp.800-807
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• 2017

컴퓨터를 이용하여 홀로그램을 생성하기 위해서는 방대한 양의 계산이 필요하다. 이를 고속화하기 위해 GPGPU(General Purpose computing on Graphic Process Unit)를 이용하여 병렬 프로그래밍을 통한 고속화 방법들이 많이 연구되었다. 본 논문에서는 홀로그램 화소 기반의 병렬처리에서 생기는 병목현상을 줄이고, 공통항을 이용한 가속화 방법을 제안한다. 또한 최적의 쓰레드를 결정하기 위해 nVidia사의 CUDA와 함께 제공되는 Visual Profiler를 이용한 최적화 방법을 소개한다. 구현 결과 기존 연구 대비 최대 40%의 계산시간을 줄일 수 있었다.

• Korean Chemical Engineering Research
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• 제43권1호
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• pp.181-185
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• 2005

인화점은 가연성 물질의 화재 및 폭발의 잠재위험성을 결정하는데 가장 중요한 연소 특성치 가운데 하나이다. 인화점의 정확한 지식은 산업 화재의 방호 평가 및 적절한 예방에 중요하다. 본 연구에서 n-butanol+n-propionic acid계와, n-propanol+n-propionic계의 개방계 인화점을 Tag식 개방계 장치(ASTM D 1310-86)를 이용하여 측정하였다. 실험값은 라울의 법칙과 van Laar식에 의해 계산된 값과 비교하였다. 그 결과, van Laar식에 의한 예측값이 라울의 법칙에 의한 예측값 보다 실험값에 더욱 근사함을 확인하였다.

• Environmental Engineering Research
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• 제22권3호
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• pp.245-254
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• 2017

This study investigates methyl orange (MO) degradation by an ultrasonically dispersed nano-metallic particle (NMP) assisted advanced Fenton process. The NMPs were synthesized from the leachate of automobile-shredder residue. X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy were performed for the prepared NMPs. Various parameters, such as the effects of the NMP dosage, the pH value of the solution, the initial concentration of MO, and the amount of $H_2O_2$ on the degradation efficiency of MO were studied. The MO degradation efficiency could be increased by approximately 100% by increasing the dosages of the NMPs and $H_2O_2$ to certain limits, after which in both cases the degradation efficiency was reduced when an excess amount was added. The MO degradation efficiency was found to be 100% at pH 2.0 and 2.5 with the 10 mg/L of initial concentration of the MO. The degradation of MO by ultrasonically dispersed NMPs was appropriate with the pseudo-first-order kinetics.

• 전자공학회논문지CI
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• 제46권1호
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• pp.11-19
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• 2009

최근, 인터넷과 같이 신뢰할 수 없는 네트워크를 통한 통신환경에서, 사용자 인증은 비밀성과 무결성 보장을 위해 보안 분야에서 가장 중요한 기술로 주목받고 있다. 특히, 패스워드 기반의 사용자 인증 방법은 비용과 효율성 측면에서 갖는 장점 때문에 가장 널리 사용되는 사용자 인증 방법이다. 본 논문에서는 해쉬 함수를 사용한 강력한 패스워드 상호인증 프로토콜을 제안한다. 결론적으로, 제안한 인증 프로토콜은 기존의 관련 프로토콜들과 비교하여 보다 많은 보안성과 효율성을 제공하여 주어, 인터넷 인증 프로토콜로 실용적으로 사용되어 질 수 있다.

• IEIE Transactions on Smart Processing and Computing
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• 제2권1호
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• pp.27-35
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• 2013

This paper proposes a face tracking algorithm for a viewpoint adaptive multi-view synthesis system. The original scene captured by a depth camera contains a texture image and 8 bit gray-scale depth map. From this original image, multi-view images that correspond to the viewer's position can be synthesized using geometrical transformations, such as rotation and translation. The proposed face tracking technique gives a motion parallax cue by different viewpoints and view angles. In the proposed algorithm, the viewer's dominant face, which is established initially from a camera, can be tracked using the statistical characteristics of face colors and deformable templates. As a result, a motion parallax cue can be provided by detecting the viewer's dominant face area and tracking it, even under a heterogeneous background, and synthesized sequences can be displayed successfully.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.271-275
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• 2007

γ -Glutamyl transpeptidase (EC 2.3.2.2) plays a key role in glutathione metabolism by catalyzing the transfer of the γ -glutamyl residue and hydrolysis of glutathione. The functional residues at the active site of the rat kidney γ -glutamyl transpeptidase were investigated by kinetic studies at various pH, the treatment of diethylpyrocarbonate (DEPC), and photooxidation in presence of methylene blue. An ionizable group affecting the enzymatic activity with an apparent pKa value of 7.1, which is in the range of pKa values for a histidine residue in protein, was obtained by examining the pH-dependence of kinetic parameters. The pH effect on the photoinduced inactivation rate of the enzyme corresponds to that expected for the photooxidation of the free histidine. The involvement of a histidine in the catalytic site of the enzyme was further supported by DEPC modification accompanied by an increase in absorbance at 240 nm, indicating the formation of Ncarbethoxyhistidine. The histidine located at the position of 382 in the precursor of the enzyme is primarily suspected based on the amino acid sequence alignment of the transpeptidases from various organisms.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.51-56
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• 2019

LuAG:Ce(Lu₃Al₅O₁₂:Ce³⁺) nano phosphor were synthesized by applying the coprecipitation method. It is used to increase the color rendering of phosphor ceramic plate for high power LEDs and laser lighting. Internal quantum efficiency and absorption of LuAG:Ce nano phosphor are 51.5 % and 64.4 %, respectively, which is higher than the previously studied nano phosphors. The maximum absorption wavelength of this phosphor is 450 nm blue light, and the emission wavelength is 510 nm. The emission wavelength shifted to longer wavelength when the concentration of Ce increased in the heat treatment of the reducing atmosphere. Thermal quenching of LuAG nano phosphor was 70 % at 200 ℃, it was explained by their significant quenching of all raman scattering modes, implying the restriction of electron-phonon couplings caused by their defects.

• Entomological Research
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• 제48권6호
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• pp.540-549
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• 2018

Climate change due to global warming and changes in land use increase the development time and distribution, as well as the abundance, of mosquitoes, thereby negatively affecting human life and health. In this study, we investigated the habitat characteristics of mosquito occurrence sites in Danwon-gu, Ansan city, Korea, based on a daily record of civil pest complaints lodged at the Danwon-gu Community Health Center. We considered two types of factors (natural and artificial) known to affect mosquito occurrence. We confirmed a total of 554 cases of mosquito occurrence from March 2014 to August 2017. The total study area was $49.11km^2$, with urban areas constituting the largest proportion. Additionally, we investigated habitat preferences of mosquitoes in terms of terrain factors; generally, mosquitoes occurred at low elevations and on low slopes. Regarding the preference of oviposition sites, mosquitoes occurred at higher rates near streams and crops lands. The rate of mosquito occurrence tended to increase in areas with dense human populations. Regarding climatic factors, the rate of mosquito occurrence increased in areas with high temperature and low precipitation.

• 공학교육연구
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• 제24권3호
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• pp.58-69
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• 2021

It is very necessary to have a creative problem-solving capacities to learn various majors and liberal arts based on the major, and to solve the bottleneck techniques led by students. In this study, the existing creative problem-solving curriculums, 'Methodology of Inventive Problem Solving' based on TRIZ, were improved and applied, and industrial bottleneck techniques were provided to students to solve these techniques. To improve the curriculum, 1) improvement of instructional objectives and learning contents, 2) improvement of evaluation methods and contents (reflecting the evaluation of instructor and students), and 3) learning satisfaction survey were conducted in the following order. As a result of the application of the improved curriculum, the level of activities for each team was improved, and when the core process was well understood, the evaluation of team activities was also excellent, but there was a tendency to focus on methods that are relatively easy to apply in the problem solving process. In the final exam (learning contents evaluation), teams with difficult understanding of the TRIZ theory or low team activities showed a relatively high trend, but the difference in level between divisions was slightly reduced.