• Membrane Journal
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• v.34 no.3
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• pp.182-191
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• 2024

This review addresses the pressing need for effective wastewater treatment methodologies by exploring advanced thin-film nanocomposite (TFN) nanofiltration membranes aimed at efficient dye removal from industrial effluents. Utilizing insights from recent research, the review focuses on the fabrication of TFN membranes incorporating innovative materials such as nanocarbons, silica nanospheres, metal-organic frameworks (MOFs), and MoS₂. The primary goals are to enhance dye removal efficiency, improve antifouling properties, and maintain high selectivity for dye/salt separation. By leveraging the distinct advantages of these nanomaterials-including large surface areas, mechanical robustness, and specific pollutant interaction capabilities-this review aims to overcome the limitations of current nanofiltration technologies and provide sustainable solutions for water treatment challenges.

• Clinical and Experimental Pediatrics
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• v.45 no.4
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• pp.459-465
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• 2002

Purpose : The aim of this study was to evaluate the latest tendency of esophageal foreign body's extraction and to obtain a consensus from recent trends of indications and techniques of flexible endoscopy of esophageal FB in children. Methods : We retrospectively reviewed medical records of 127 cases with foreign bodies in esophagus at Dept. of Pediatrics and Otorhinolaryngology, Gyeongsang National University Hospital (GNUH) from Jun, 1987 to July, 2001. They were divided into two groups by the kinds of endoscopy : flexible endoscope(66 cases) or rigid endoscope(61 cases). Rigid endoscopy was performed under general anesthesia at Dept. of Otorhinolaryngology but flexible endoscopy was performed without general anesthesia or sedative drugs(midazolam or diazepam). Results : An annual number of cases of two groups were similar from 1991 to 1998. But from 1999, flexible endoscopy was performed actively. Asymptomatic cases were frequently observed in flexible endoscopy(28 cases/66 cases) but swallowing difficulties were frequently observed in the rigid endoscopy group(25 cases/61 cases). Other symptoms were vomiting, irritability, chest discomfort and abdominal pain. The total number of cases with underlying disease(esophageal stenosis, cerebral palsy) was 8. The total number of cases with complications (erosion, ulcer, bleeding, perforation) was 11. The above cases were not correlated between the two groups. In 55 cases(83.3%) of the flexible endoscopic group and 53 cases(86.8%) of the rigid endoscopic group, foreign bodies in the esophagus were removed within 24 hours. Conclusion : We could not find any benefit in rigid endoscopic technique. Flexible endoscopic FB removal can be performed safely and effectively in children by an experienced endoscopist.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.151.2-151.2
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• 2010

본 연구는 하이드로퀴논(HQ)을 이용하여 매립가스로부터 이산화탄소를 선택적으로 분리하고 유기 크러스레이트 형태로 분리 및 저장에 적용하기 위한 연구로써 하이드로퀴논을 다양한 객체가스와 반응시키면서 열역학적 안정영역을 파악하고 분광학적 방법을 이용하여 미세구조 변화를 분석하고자 하였다. 먼저 ${\alpha}$-HQ를 고압(4MPa)의 이산화탄소와 반응시켜 이산화탄소가 포집된 ${\beta}$-HQ를 합성하였고, 동공 내에 존재하는 이산화탄소를 제거하여 동공을 유지하는 empty ${\beta}$-HQ를 만들었다. 온도를 증가시키면서 XRD 패턴을 측정한 결과 298 K 에서 378 K 사이에서 ${\beta}$-HQ 시료는 서서히 empty ${\beta}$-HQ 의 구조로 전환되었으며 378 K 이상의 온도에서 ${\alpha}$-HQ 구조로 급격히 전환되었다. 또한 생성된 empty ${\beta}$-HQ 동공에 이산화탄소가 포집, 해리되는데 있어서 온도의 영향을 확인하기 위해 298K과 343K의 온도에서 실시간 라만분광법으로 측정하였다. 그 결과 298K에서 약 200분의 시간이 지난 후 이산화탄소는 하이드로퀴논 동공 내로 포집되어 안정화되었으며 압력해방 후에는 빠져나가지 않고 동공 내에 존재함을 확인하였다. 그러나 343K에서는 급격히 포집되어 30분 이내 안정화되었고, 압력해방 후 동공 내에 존재하지 못하고 빠져나가는 것을 확인하였다. Empty ${\beta}$-HQ의 이산화탄소 선택도를 관찰하기 위해 이산화탄소와 메탄, 수소, 질소의 조성이 각각 30%, 30%, 20%, 20%인 혼합가스와 반응시킨 후 가스 크로마토그래프 분석을 실시한 결과, empty ${\beta}$-HQ내 포집된 가스 중 이산화탄소의 조성이 약 80% 이상으로 나타나 높은 선택도를 나타냄을 관찰하였다.

• Clean Technology
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• v.12 no.2
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• pp.87-94
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• 2006

The reduction of $SO_2$ to elemental sulfur by CO over a series of iron niobate with nominal Nb/Fe atomic ratios of 1/0, 10/1, 5/1, 1/1, 1/5, 1/10 and 0/1 was studied with a flow fixed-bed reactor. Strong synergistic phenomena in catalytic activity and selectivity were observed for the iron niobate catalysts, and the best catalytic performance was observed for the catalyst with Fe/Nb atomic ratio of 1/1. The active phase of the activated iron niobate catalysts was identified to be $FeS_2$ using XRD and XPS. Selective reduction of $SO_2$ by CO was followed by the COS intermediate mechanism.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.129-136
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• 2020

In this paper, we propose a thermal imagery-based object detection algorithm for low-light level nighttime surveillance system. Many features selected by Haar-like feature selection algorithm and existing Adaboost algorithm are often vulnerable to noise and problems with similar or overlapping feature set for learning samples. It also removes noise from the feature set from the surveillance image of the low-light night environment, and implements it using the lightweight extended Haar feature and adaboost learning algorithm to enable fast and efficient real-time feature selection. Experiments use extended Haar feature points to recognize non-predictive objects with motion in nighttime low-light environments. The Adaboost learning algorithm with video frame 800*600 thermal image as input is implemented with CUDA 9.0 platform for simulation. As a result, the results of object detection confirmed that the success rate was about 90% or more, and the processing speed was about 30% faster than the computational results obtained through histogram equalization operations in general images.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.77-85
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• 2017

The goal of the study was to examine undergraduate students' perception of the importance of the concept of system in science. The participants are six undergraduate students in the department of science education. Data sources included interviews and interview notes. Results showed that students understood the concept of system as a group of objects, space, and boundaries, which differed from a previous research study about its details. The students also were able to explain the concept of system related with the process of problem solving. The students recognized as well the selection of system for analysis of natural phenomenon, explaining that the selection of system was determined by purpose of the observer. Lastly, the students explained that the concept of system was useful for science learning because it was strongly related with other science concepts, understanding of interactions, and learner's cognitive development.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.181-191
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• 2002

Video based surveillance systems based on an active camera require a fast algorithm for real time detection and tracking of local motion in the presence of global motion. This paper presents a new fast and efficient motion detection and tracking algorithm using the displaced frame difference (DFD). In the Proposed algorithm, first, a Previous frame is adaptively selected according to the magnitude of object motion, and the global motion is estimated by using only a few confident matching blocks for a fast and accurate result. Then, a DFD is obtained between the current frame and the selected previous frame displaced by the global motion. Finally, a moving object is extracted from the noisy DFD by utilizing the correlation between the DFD and current frame. We implement this algorithm into an active camera system including a pan-tilt unit and a standard PC equipped with an AMD 800MHz processor. The system can perform the exhaustive search for a search range of 120, and achieve the processing speed of about 50 frames/sec for video sequences of 320$\times$240. Thereby, it provides satisfactory tracking results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1186-1193
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• 2000

In this paper, the system performance with the selection diversity, which is applied to the FH/MFSK system in Nakagami fading channel, is analyzed. The deletion probability is derived from the received signal to noise ratio(SNR) after selection combining and the parameters such as the number of users(M), SNR, Nakagami fading figure(m), and the number of diversity branches(D) is used for the performance analysis of the FH/MFSK system. Assuming that m set 1, it is observed that the bit error rate(BER) is 1.0$\times$$10^{-3}$ and 1.0$\times$$10^{-4}$ at D =1(no diversity) and D=2, respectively, and then is decreased by 10 times. Assuming that m set 2, it is also shown that the BER has a constant value although D is increased. In the case of D=2, the system capacity is more 75% and 20% than that considering no diversity at SNR=15 dB and 25 dB, respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.5
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• pp.596-600
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• 2010

This paper proposes hough transform-based semi-automatic vertex detection algorithm for object modeling on a mobile phone supporting touch-screens. The proposed algorithm shows fast processing time by searching the limited range of parameters for computing hough transform with a small range of ROI image. Moreover, the proposed algorithm removes bad candidates among the detected lines by selecting the two closest candidate lines from the position of user's input. After that, it accurately detects an interesting vertex without additionally required interactions by detecting an intersection point of the two lines. As a result, we believe that the proposed algorithm shows a 1.4 pixel distance error on average as a vertex detection accuracy under such conditions as a 5.7 pixel distance error on average as an inaccurate input.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.27-34
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• 2010

This paper presents a methodology for classifying left and right motor imagery using a neural network with weighted fuzzy membership functions (NEWFM) and wavelet-based feature extraction. Wavelet coefficients are extracted from electroencephalogram(EEG) signal by wavelet transforms in the first step. In the second step, sixty numbers of initial features are extracted from wavelet coefficients by the frequency distribution and the amount of variability in frequency distribution. The distributed non-overlap area measurement method selects the minimized number of features by removing the worst input features one by one, and then minimized six numbers of features are selected with the highest performance result. The proposed methodology shows that accuracy rate is 86.43% with six numbers of features.