• The Journal of Engineering Geology
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• v.24 no.2
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• pp.283-295
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• 2014

Groundwater monitoring wells are important to maintain their performance for long term monitoring. The monitoring wells with extensive internal incrustation by clay adsorption were selected for this study. The performance of these monitoring wells was improved by pump washing, tube replacements for dedicated samplers, and well surging. After each improvement, the Mg, Mn, and Zn concentrations were increased. The results show that under these conditions, the monitoring wells must be carefully inspected at least once a year. Even in the case of no abnormal phenomenon like as internal incrustation, the monitoring wells need to be serviced at least once every four to five years to guarantee that they are effectively monitoring groundwater quality.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.228-228
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• 2018

강변여과는 지하수 인공함양 방식 중 유도함양(induced recharge) 또는 간접함양 방식에 속한다. 이는 하천 및 강변 부근에 집수시설을 설치한 후, 미고결층 대수층(unconsolidated aquifer)의 자연 오염 저감능을 이용하여 지표수를 간접 취수하는 방식으로 수질이 불량한 지표수가 대수층을 관류하면서 희석, 화학적 이온 교환 및 반응, 흡착, 생물막(biofilm; 미생물에 의한 자연저감), 여과 등을 통하여 수질이 개선된다. 강변여과수내의 용존 농도가 높은 철과 망간은 수처리 비용증가, 용수관정 및 시설물의 수명단축을 초래한다. 따라서 강변여과 지역의 미고결 대수층에서 효과적인 철과 망간 동시 제거(vyredox)를 위해 에어서징(air surging)과 블록 서징(block surging)을 실시하기 위해서 실내 물탱크 모델(water tank model)에서 에어서징에 따른 공기 순환 우물시스템을 관찰하였으며, 이를 바탕으로 현장시험(Test bed)에 적용하였다. 미고결 대층수층에서의 철 망간은 음용수 기준치(각각 0.3 mg/L)를 초과하고 있으며, 강변여과 취수 개발 및 이용을 제한하는 요인이 되고 있다. 본 연구에서 사용된 에어서징과 블록서지 기술은 자갈층 및 미고결 대수층에 충진된 슬라임 및 폐색(clogging)을 제거함과 동시에 관정 주변의 대수층의 투수성 개선과 산화환경으로 치환되며, 대수층에 잔존하는 철/망간의 산화물들을 관정내로 빼낼 수 있는 방법이다. 따라서 서징에 따른 폐색 제거효율을 검토한 결과에서 철 망간 이온농도 저감효과와 관정 주변의 수리전도도(hydraulic conductivity) 및 저류계수(coefficient of storage)가 증가한 것으로 나타났다. 이와 같이 강변여과에 의한 폐색은 미고결층내 공기주입 및 블록서지를 통하여 철/망간 이온농도 저감 및 수리특성 개선 효과에 유용한 것으로 평가된다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.418-430
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• 2014

In this paper, a modelling technique for simulating self-propelled ships in waves is presented. The flow is modelled using a RANS solver coupled with an actuator disk model for the propeller. The motion of the ship is taken into consideration in the definition of the actuator disk region as well as the advance ratio of the propeller. The RPM of the propeller is controlled using a PID-controller with constraints added on the maximum permissible RPM increase rate. Results are presented for a freely surging model in regular waves with different constraints put on the PID-controller. The described method shows promising results and allows for the studying of several factors relating to self-propulsion. However, more validation data is needed to judge the accuracy of the model.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1580-1586
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• 2003

This paper presents the design and the analysis of a "fish-like underwater robot". In order to develop swimming robot like a real fish, extensive hydrodynamic analysis were made followed by the study of biology of the fishes especially its maneuverability and propel styles. Swimming mode is achieved by mimicking fish-swimming of carangiform. This is the swimming mode of the fast motion using its tail and peduncle for propulsion. In order to generate configurations of vortices that gives efficient propulsion yawing and surging with a caudal fin has applied and in order to submerge and maintain the body balance pitching and heaving motion with a pair of pectoral fin is used. We have derived the equation of motion of PoTuna by two methods. In first method, we use the equation of motion of underwater vehicle with the potential flow theory for the power of propulsion. In second method, we apply the method of the equation of motion of UVM(Underwater Vehicle-Manipulator). Then, we compare these results.

• Journal of Haehwa Medicine
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• v.15 no.1
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• pp.105-110
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• 2006

Generally, Hwabyung is more common in older women, in low educational group. Many psychiatrists explain it as the illness originated from a series of psychological stresses. And they think that Hwabyung patients have somatization disorder, anxiety disorder, and major depression. But, many of oriental medical doctors explain it as symptoms having the character of fire. In this case, we described a 67-years old woman who diagnosed as Hwabyung. She complained flush face with surging feeling, headache, dizziness and depression, and her condition was improved through oriental medical treatment such as acupuncture and herbal medicine about 5 weeks.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.4
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• pp.22-29
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• 2003

New high-speed depressurized circulating water channel was designed by using the CFD code. Flow in the channel has free surface and pressure in the test section can be depressed. In this study, Flow separation and bubble occurrence were considered in designing the contraction nozzle shape for better flow uniformity Tn the test section. To supplement velocity defect due to the free surface, nozzle injection system more effective in high-speed flow was installed instead of drum system. Necessary power and injection techniques were proposed. And guide vane arrangement was analyzed to reduce the flow resistance and keep quiet free surface from ´surging´. Wave absorber was devised to reduce the wave resistance and to prevent the entrainment of air to the diffuser.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.39-40
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• 2003

This research surveys the effects of POY physical properties and processing conditions of belt texturing machine to the draw textured yarns. The various textured yarns are made with variation of 1st heater temperature, draw ratio and velocity ratio, and the physical properties of these specimens such as yarn linear density, tensile properties and wet and dry thermal shrinkages are measured and analyzed with POY physical properties and processing conditions of texturing machine. Especially yarn mechanical properties of DTY are analysed with the variation of untwisting tension (T$_2$) on the untwisting part in DTY process and thin and thick DTY yam model are proposed with surging phenomena in DTY process.

• International Journal of Contents
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• v.3 no.1
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• pp.9-13
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• 2007

This paper proposes a policy on efficient load balancing that can reduce the network game server load burdened by surging number of users. The study adopted a contents-based clustering technique. Recently, skyrocketing number of clients in on-line games causes overloads on specific game servers, and the consequent server-instability brings the worst situation: a server failure. To cope with this problem, one can install more high-powered servers or be equipped with back-up servers, which is often inefficient in terms of cost performance. To solve this problem, the present study examined the technology enhancing the performance and efficiency of game servers by reducing the loads of specific game servers. In doing this, this study used the clustering technology to compose game servers classified by their contents and carried out appropriate load balancing to numerous clients with load balancers in each region.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.4
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• pp.1-7
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• 2019

Cooling using the Han River has recently been spreading. The Ministry of Trade, Industry and Energy submitted a revised enforcement ordinance to include river water in renewable energy. Therefore, it is necessary to analyze the water temperature characteristics of Han River. Especially, it is necessary to investigate the effect on hot summer. In this study, we analyzed the water temperature of the last 11 years. It is intended to utilize the Han River for building cooling in the future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.221-224
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• 2010

The introduction of BIM-based project has increased in the domestic recently. Therefore the demand of BIM professionals is surging combined with the necessity of BIM education. However BIM education done in the domestic industry and public organization is only focusing on the 3D modeling, As a result an educatee could not put the real intention of BIM into practice. Thus through this study the wrong recognition of BIM will be corrected and this study analyzes the problems of domestic BIM-based project. This study examines the improvement of domestic BIM education cases by drawing the capability of BIM professionals.