• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.649-655
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• 2004

The behavior of biological particles in DAF (dissolved air flotation) process was analyzed by employing PBT (Population balance theory). After decline growth phase of activated sludge, the value of the initial collision-attachment efficiency was increased over than 0.35 corresponding relatively high value in the whole life cycle of microorganism. For practical application of DAF as a solid separation process. It is desirable that microbial particles should be operated to perform high solid removal efficiency in biological wastewater treatment.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.411-417
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• 2014

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.135-142
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• 2014

The performance of inorganic sludge separation system is evaluated. Anaerobic digester effluent sludge is used for feed sludge of this system and hydrocyclone is used for inorganic sludge separation. For phosphorus removal and recovery $MgCl_2$ is pumped into MAP growth tank, a component of inorganic sludge separation system. Using this system inorganic sludge which contained less than 40 % of organic matter can be discharged stably and the maximum amount of separated inorganic sludge is 13.4 % of influent sludge based on dry solid. The amount of phosphorus recovered as MAP(as P) is 16.7 % to influent T-P.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.717-725
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• 2002

A bench-scale submerged-type membrane filtration system (SMFS) was constructed to study a feasibility of membrane filtration for solid-liquid separation in water and wastewater treatment processes. In the case of applying the SMFS to a biological wastewater treatment process, so-called membrane bioreactor, aeration underneath membrane modules is usually employed in order to provide oxygen demand for microbial growth as well as to control membrane fouling. A study was investigated the effects of operation parameters by aeration intensity, feed concentration, foulant type and airlift pore size on critical flux. Critical flux tends to increase with aeration rate. Optimal aeration flow rate was found to be 10 L/min/module. Feed concentration and foulant type has a significant effect on membrane fouling and filtration performance. But downward position and pore size of airlift has no a significant effects on membrane fouling and filtration performance.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.293-294
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• 2021

본 연구는 어업에 종사하는 어업인을 대상으로 작업복 착용실태와 불편사항 및 문제점, 작업복에서 요구되는 기능 등을 알아보고 이를 통해 어업에 적합하고 작업 효율성을 높일 수 있는 기능적 작업복 개발에 필요한 요구사항을 파악하고자 하였다. 본 연구는 전남지역의 어업인 124명을 대상으로 하였다. 분석은 SPSS 26.0 프로그램을 활용하였다. 본 연구에 참여한 어업인은 50대가 가장 많았고 남성이 약 85%이며, 근무경력은 10년 이상 20년 미만이 많았다. 작업복은 상하 분리형을 좋아하며, 방수성을 가장 중요하게 생각하였다. 착용 작업복에 대한 만족도는 땀투과성을 제외한 모든 항목에서 보통으로 평가되었다. 선호하는 색상은 무채색이 가장 많고 상하 분리형 스타일과 지퍼 여밈을 좋아하였다. 연령에 따라 작업복 구입 시 고려사항에 유의미한 차이를 나타내 30대 이하와 40대는 활동성을, 50대는 내구성을, 60대는 방수성을 가장 중요하게 생각하였다. 연령에 따른 작업복 만족도는 활동성, 압박감, 탈착성, 맞음새, 두께감, 기능성, 보온성, 옷의 무게감 등에서 유의미한 차이를 나타냈다. 본 연구를 바탕으로 하여 실용적이고 기능적인 어업용 작업복 개발이 이루어져야 할 것으로 생각된다.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.471-478
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• 2011

A series of laboratory experiments carried out to investigate the particle separation efficiency and flotation characteristics using $CO_2$ bubbles. The primary objective of this study was to find out the feasibility of $CO_2$ bubbles as an applicable unit of flotation process in tap-water and wastewater treatment plant. The fundamental measurements were conducted to characterize the $CO_2$ bubble from the physical viewpoint in water including bubble size distribution and rising velocity under various operational conditions. In addition, the removal efficiency of solid was experimented using the lab scale plant applied $CO_2$ bubbles, namely the dissolved carbon dioxide flotation (DCF) process. The DCF process using carbon dioxide bubble, which is an advantage as the decrease and the reuse of Green-House gas, can be a promising technology as an water treatment process. On the other hand, the further research to decrease the bubble size distribution of $CO_2$ is required to enhance the particle separation efficiency.

• 한국해양학회지
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• v.28 no.1
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• pp.17-23
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• 1993

A right cylindrical tank with sloping bottom and top (${\beta}-effect$) is filled with two-layered fluid and is put on the rotating table. External fluid of same density as the lower-layer fluid is continuously injected to drive the lower-layer current. By minimizing the interfacial stress between two layers the motion in the lower-layer deformed the shape of interface such that the upper-layer adjust itself to the variations of the interface in terms of its direction of flow patterns .The most significant parameter is the internal Froude Number($F_1$) and when $F_1$ is greater than 6 two-cellular circulation of the upper-layer changes its direction, there by creates a separation of Western boundary current. The separation position moves to the most northward when $F_1$ equals to 6.

• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.61-67
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• 1977

Seed separation from half-cut red pepper were investigated with free falling, up-and-down shaking and rotating collision methods. The separation rates were related with impact appiied and the rotating case was distinguished from the other two methods. Beside the impact effect, velocity of the pod and tumbling factors were involved. Momentum effectiveness of seed separation were calculated as $2.50{\times}10^{-6}$, $2.09{\times}10^{-6}$, and $3.94{\times}10^{-8}$ for free falling, shaking and rotating method on the same velocity basis, respectively. The tendency of separation rate was similar to that of red pepper drying rate against time.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.462-464
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• 2018

본 논문은 촬영된 치아의 CT영상에서 치아의 상악과 하악의 분리 알고리즘을 제안한다. 촬영 기기의 노후화, metal artifact, 치아 부정합 등 외부 요인에도 강인한 성능을 보이도록 알고리즘을 설계하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.169-175
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• 2016

There are many researches to develop robots that improve its mobility and task planning to adapt in various uneven environments. In this paper, we propose the design method and task planning of quadruped robot which can have top-bottom docking structure. The proposed quadruped robot is designed to adjust leg length using linear actuators and perform top-bottom docking and undocking using octagonal cone shaped docking module. Also, to stable walking and information gathering in the various environments, a geomagnetic sensor, PSD sensor, LRF sensor and camera. We propose an obstacle avoidance method and the topbottom docking algorithm of the two quadruped robots using linear actuator. The robot can overcome obstacles using adjusting leg length and activate the top-bottom docking function. The top-bottom docking robots of two quadruped robot can walk 4 legged walking and 6 legged walking, and use 4 arms or 2 arms the upper. We verified that the docking robots can carry objects using 4 leg of the upper robot.