• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.486-492
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• 2004

CMP (Chemical mechanical polishing) is inevitable process to overcome $0.2{\mu}m$ wire thickness in semiconductor industry. In this study, effect of pressure to separate used CMP slurry into solid and liquid for recycle and reuse by ultrafiltration was investigated. Also, water quality after the ultrafiltration such as turbidity and TDS was evaluated. The material of membrane used in the study was PVDF. The used CMP contained 0.5% of solid content and then concentrated up to 18% by weight. The used CMP can not be concentrated higher than 18% because of viscosity and abrasion of pump. The tested feed pressures were 22.1, 29.4 and 36.8 psi. The results have shown that operating at 36.8 psi has advantages on operation time and total flux. The specific flux showed some variation at 1 to 15 of concentration factor but no difference after 15 of concentration factor. Mass balance of solid at initial stage of the operation showed some unbalance because of deposition of solid on the membrane, which was main reason to reduce flux. Turbidity was very stable at lower than 0.2NTU for 22.1 and 36.8 psi of feed pressure.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.25-32
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• 2017

Most of weapon systems use aided navigation system which integrates inertial navigation and aiding sensors to compensate the INS errors increasing with the passage of time. Various aid sensors can be applied such as Global Navigation Satellite System (GNSS), radar, barometer, etc., but there might exist time delay caused by signal processing or transferring aid information. This time delay leads out-of-sequence measurements (OOSM) systems. Previously, optimal and suboptimal measurment update method for OOSM systems, where the time delay length are known, are proposed. However, previous algorithm does not guarantee the positive definite property of covariance matrix. In order to improve numerical stability for aided navigation using delayed-measurement, this paper proposes a new measurement covariance update algorithm be similar to Joseph-form in Kalman filter. Futhermore, we propose how to implement it in indirect feedback Kalman filter structure, which is commonly used in aided navigation systems, for time-delayed measurement systems. Simulation and vehicle test results show effectiveness of a proposed algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.385-390
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• 2015

Quay cranes are considered core equipment for container terminal operation. However, unmanned operation systems have not as yet been announced due to the technological difficulties of implementation. In this paper, we developed a wireless controller to control a quay crane simulator remotely and conducted its performance test, a first step toward unmanned operation of quay cranes. The communication delay of a developed wireless controller was about 9.4ms on average while that of existing wired controllers was about 5.6ms. The same functions were implemented and tested on a smart phone where the average communication delay was 7.3ms. In addition, to apply the developed system into a real environment, we proposed a network architecture based on IEEE 802.11ac and carried out its performance evaluation. When the distance between two nodes was 50m apart, the throughputs of the TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) were 57Mbps and 189Mbps, respectively. The communication delay of the control data was 9.1ms through the TCP channel. These results reveal the proper working of remote quay crane operation if we adopt the IEEE 802.11ac network.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.06a
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• pp.26-28
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• 2017

스마트폰 보유율과 모바일 이용 행태가 급변함에 따라 방송사에서는 양방향 서비스를 포함한 다양한 방송 서비스를 제공하려고 노력하고 있다. 양방향 서비스 방송에서 시청자가 보낸 문구를 실제 화면에 보여주기까지 PD 와 담당자들의 수작업이 필요하다. 하지만 하루 평균 약 7,200 건 (MBC 오늘아침 소통중계)의 양방향 서비스 관련 로그가 남게 되어, PD 가 일일이 판별하기에는 많은 노력이 따른다. 이러한 불필요한 노력을 줄이기 위해 본 논문에서는 감정 분석을 이용한 딥러닝 인공지능 기반 양방향 서비스 방송 소프트웨어 시스템을 제안한다. 첫째, 시청자들이 전송한 의견, 건의사항, 내용 등을 전처리 과정을 진행한다. 둘째, 감정 사전을 이용해 전처리 된 단어와 비교하여 시청자가 보낸 문구의 감정 점수를 계산한다. 셋째, 과거 실제 방송에 송출된 시청자 문구를 감정 점수와 함께 딥러닝을 이용하여 훈련시킨다. 본 논문의 성능을 평가하기 위해, 2017 년 생방송 오늘아침 소통중계에 사례연구를 진행하였고 효율성을 보였다. 앞으로 이러한 양방향 서비스 방송 소프트웨어 시스템 도입으로, PD 가 방송 제작에 더욱 집중 할 수 있도록 차별화된 방송을 준비하는데 크게 기여할 것이라 기대한다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.2
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• pp.115-125
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• 2017

Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear in fishing operation is generally related to hydrodynamic resistance on the gear. This research is to propose a low drag generated midwater trawl in terms of the gear design improvement using simulations. The results from the simulation were verified with results that mirrored the model experiments. From the results, the resistance force of the proposed gear decreased to 29% compared to that of the current gear. Furthermore, the gear performance also improved with increased gear mouth compared to the current one. Therefore, the proposed gear will be helpful to reduce the greenhouse gases from fishing operation. It will also contribute to the fishing industry by saving fuel.

• Journal of the Korean Institute of Gas
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• v.7 no.3 s.20
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• pp.18-23
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• 2003

The demand of LNG in Korea has dramatically increased since it was first imported in 1986. Thus, more LNG storage tanks are required to meet the growing consumption of LNG. However the design, construction, and analysis of LNG storage facility need highly advanced technology compared to the general structures due to the fluid-structure interaction and the low temperature of LNG. Recently Korea Gas Corporation(KOGAS) constructed a pilot LNG storage tank, and it is in operation to develop and accumulate the core technology. As a part of those objects, the fundamental dynamic test for the pilot tank were performed. For this study, dynamic test were carried out and the dynamic characteristics of the pilot tank were verified and analyzed.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.271-280
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• 2020

Due to the development of the urban economy, high-density buildings and skyscrapers have continued to increase in order to alleviate high population densities and to make efficient use of urban space. However, a fire in a high-rise building is a disaster that can lead to massive casualties and property damage because of the difficulty of firefighting and escaping. Various studies have been conducted on these high-rise buildings because they are sympathetic to these difficulties all over the world. In this paper, trends of researches and technologies related to fire in high-rise buildings are analyzed synthetically through thesis and patent data. In other words, we explored the trends of various studies that have been carried out so far through the thesis, and performed technical monitoring on actual implemented technology and newly implemented technologies through patent data. Through this research, we have studied the present and the future of technology for high-rise building fire.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.145-152
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• 2018

This study is focused on manganese (Mn(II)) removal by ozonation in surface water. Instant ozone demand for the water was 0.5 mg/L in the study. When 0.5 mg/L of Mn(II) is existed in water, the optimum ozone concentration was 1.25 mg/L with reaction time 10 minutes to meet the drinking water regulation. The ozone concentration to meet the drinking water regulation was much higher than the stoichiometric concentration. The reaction of soluble manganese removal was so fast that the reaction time does not affect the removal dramatically. When Mn(II) is existed with Fe, the removal of Mn(II) was not affected by Fe ion. However As(V) is existed as co-ion the removal of Mn(II) was decreased by 10%. Adding ozone to surface water has limited effect to remove dissolved organic matter. When ozone is used as oxidant to remove Mn(II) in the water, the existing co-ion should be evaluated to determine optimum concentration.

• Journal of the Korean GEO-environmental Society
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• v.19 no.7
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• pp.5-11
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• 2018

Instead of a single pile, group piles are usually used for the pile foundation. If the earthquake occurs in the ground where group piles are installed, dynamic behavior of group piles are affected not only by interaction of piles and the ground movement but also by the pile cap. However, in Korea, the pile cap influence is not taken account into the design of group piles. Research on dynamic behavior of group piles has been performed only to verify interaction of piles and the ground and has not considered the pile cap as a factor. In this research, 1g shaking table model tests were performed to verify the thickness of the pile cap affects dynamic behavior of group piles that were installed in the ground where the earthquake would occur. The test results show that, as thickness of the pile cap increased, acceleration and horizontal displacement of the pile cap decreasd while vertical displacement of the pile cap increased. The results also showed that, among the group files tested, acceleration, horizontal displacement, and vertical displacement of the bearing pile are smaller than those of the friction pile.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.671-678
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• 2007

2-methylisoborneol (MIB) is a musty odor compound produced as a secondary metabolite by some cyanobacteria and actinomycetes. It is lead to distrust in tap water due to taste and odor. It is well known that activated carbon (AC) adsorption is the best available technology to remove 2-MIB and geosmin. In this study, physical characteristics of virgin AC and reactivated AC was compared. The effect of variation of NOM molecular weight on adsorption of 2-MIB in virgin AC and reactivated AC were also evaluated. BET surface area was decreased by 13 to 23% and total pore volume was decreased by 18 to 21% due to first and second reactivation compare to the virgin carbon. However, mesopore volume ($V_{meso}$) was increased about 14% after reactivation. It showed that micropore volume was decreased and move to mesopore or macropore after reactivation. Decreased adsorption capacity of 2-MIB was greatly related to below 3000Da. Adsorption capacity of 2-MIB was rather greater in virgin AC than in reactivated, which is strongly related to micropore volume.