• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.155-160
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• 2002

In this paper, a compliant buoy mooring system of a floating cylindrical structure in shallow water depth is studied experimentally. The compliant buoy mooring system consists of four buoys, vertical mooring legs and horizontal mooring lines. A series of model test were carried out at KRISO ocean engineering basin for various mooring parameters; line length, pretension of mooring leg and mooring layouts and environmental conditions; regular and irregular waves combined with current and wind. The mooring line tensions and 6-DOF motions of the floating structure were measured using water-proof load cells and 3 CCD camera system. The results of a series of model tests were discussed on nonlinear motion behaviors of the floating structure and characterisitics of cumulative distributions of mooring line peak tensions.

• Journal of Advanced Research in Ocean Engineering
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• 제2권4호
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• pp.179-191
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• 2016

As the demand for renewable energy has increased following the worldwide agreement to act against global climate change and disaster, large-scale floating offshore wind systems have become a more viable solution. However, the cost of the whole system is still too high for practical realization. To make the cost of a floating wind system be more economical, a new concept of tension leg platform (TLP) type ocean floating wind system has been developed. To verify the performance of a 5-MW TLP type ocean floating wind power system designed by the Korea Advanced Institute of Science and Technology, the FAST simulation developed by the National Renewable Energy Laboratory is used. Further, 1/50 scale model tests have been carried out in the ocean engineering tank of the Research Institute of Medium and Small Shipbuilding, Korea. This paper compares the simulation and ocean engineering tank test results on motion prediction and tension assessment of the TLP anchor.

• 한국항해학회지
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• 제18권4호
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• pp.33-47
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• 1994

On developing port system, the performance tests of system in relation to ship maneuver generally consists of the three parts: the channel transit, the manoeuvring in a turning basin and the docking/undocking. The quantifications of risk of an accident has priviously been difficult due to the low occurrence of accidents relative to the number of transits. Additionally, accident statistics could not be related port system because of the large number of factors contributing to the accident. such as human error, equipment failure, visibility, light, traffic. etc. In case of the channel transit, "Relative Risk Factor(RRF)" or "Relative Risk Factor for Meeting Traffic" was proposed as the as the measures derived to quantify the relative risk of accident by M.W.Smith. This factor measure the tracking performance, the turning performance and the passing performance at meeting traffic. On the other hand, the safety of berthing maneuver is not measured with a few evaluating factors as controlled due to complex controllabilites such as steering, engine, side thrusters or tugs. This work, therefore, aims to propose the evaluating measure by the Analytic Hierarchy Process(AHP). Six experimental scenarios were establised under the various environmental conditions as independent variables. In every simulation, the difficulty of maneuver was scored by captain and compared with AHP scores. The results show almost same and from which the weights of eight evaluating factors could be fixed. Additionally, the limit value of relative factor in berthing safety to six scenarios could be estimated to 0.11.e estimated to 0.11.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.557-561
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• 2016

인도네시아는 수자원을 관리하는 기관이 총 9개 부처이지만 지역 단위로 가면 각각의 에이전시가 존재하는 등 복잡한 이해관계가 얽혀 있어 효율적인 수자원 관리 및 운영 기술에 많은 어려움이 있다. 이에 인도네시아 국립 수자원연구소(PusAir, Puslitbang Sumber Daya Air)와 공동으로 Cisangkuy 유역 내 다양한 시설물의 연계운영 효과를 분석하여, 한정된 수자원을 다양한 수요처에 원활히 공급함으로써, 지역민과 관리기관간의 이해관계를 해소하고 최적의 수자원 활용방안들에 대한 연구를 수행하고 있다. 본 연구에서는 Cisangkuy 유역 내 Cisangkuy 강 상류부의 기존 수력 댐 운영과 상수량 증대를 위해 계획 중인 신규댐에서의 추가용수 공급을 고려한 연계운영 효과분석을 수행하여 수자원의 효율적인 활용을 위한 기초자료를 제시하고자 한다. Cisangkuy 유역에 대하여 현재 용수체계에 대한 모형의 적정성 검토를 수행하였으며, 기존 수력댐 저수지 시스템 운영효율에 대하여 물수지분석을 검토한 결과, 현 운영체계보다 최적 운영시 수력발전소 발전용량이 증가되는 것으로 검토되었다. 이와 같은 모형 구축자료는 현재 Cisangkuy 유역에 대하여 체계적인 운영방안이 없는 상태에서 대상유역 내 다양한 시설물 연계운영효과 도출을 위한 자료가 될 수 있으며, 국내 연구진들이 향후 인도네시아 수자원활용 계획 수립 시 기초자료 활용측면에서 유용할 것으로 예상된다.

• 대한조선학회논문집
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• 제58권6호
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• pp.407-414
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• 2021

The manoeuvrability of a ship with an unwanted heel angle due to a maritime accident is changed from the original characteristics. The purpose of this study is to quantitatively investigate the change in the manoeuvring performance of a twin-screw ship under various hee angles and speed conditions. A series of free running model test campaigns were performed in the Ocean Engineering Basin of Korea Research Institute of Ships & Ocean Engineering (KRISO) for a twin-screw car ferry vessel. Turning circle test and zig-zag 10/10 and 20/20 tests were carried out on the heel angles of 0, -10, and -19.5 degrees. In addition, two-speed conditions were considered to understand the effect of ship speed. In order to examine the effect of the bilge keel, a heel angle of -22 degree where the bilge keel is exposed outside the water surface, was considered. Finally, the change of manoeuvring characteristics according to the heel angle for a twin-screw and a single-screw vessel is discussed.

• Membrane and Water Treatment
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• 제13권5호
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• pp.219-225
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• 2022

5th Assessment Report of the Intergovernmental Panel on Climate Change Weather (AR5) predicts that recent severe hydrological events will affect the quality of water and increase water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed, and solar radiation) were compiled into a representative concentration curve (RC), defined using 8.5. AR5 and future use are calculated based on land use. Semi-distributed emission model Calculate emissions for each target period. Meteorological factors affecting water quality (precipitation, temperature, and flow) were input into a multiple linear regression (MLR) model and an artificial neural network (ANN) to analyze the data. Extensive experimental studies of flow properties have been carried out. In addition, an Acoustic Doppler Velocity (ADV) device was used to monitor the flow of a large open channel connection in a wastewater treatment plant in Ho Chi Minh City. Observations were made along different streams at different locations and at different depths. Analysis of measurement data shows average speed profile, aspect ratio, vertical position Measure, and ratio the vertical to bottom distance for maximum speed and water depth. This result indicates that the transport effect of the compound was considered when preparing the hazard analysis.

• 한국지역지리학회지
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• 제14권3호
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• pp.212-223
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• 2008

한라산 어리목의 어승생오름 표고 $965{\sim}1,169m$에 위치하는 실험 유역의 수문 자료와 인근 어리목 관측소의 기상 자료를 이용하여 제주도 단성화산에서 일어나는 강우의 분배 특성을 검토하였다. 어승생오름은 스코리아콘으로 실험 유역의 면적은 $51,000m^2$이며 식생은 낙엽활엽수인 서어나무와 졸참나무가 우점하고 있다. 수문 자료의 일부 결측으로 인하여 전반기(2007년 4월 30일$\sim$9월 12일)와 후반기(10월 7일$\sim$11월 19일)로 관측 기간을 구분하여 분석하였다. 실험 유역에서는 총강우량 2,296.5mm 가운데 20.2%에 해당하는 465mm가 유역 유출량으로 분배되며, 실제 증발산량은 강우량의 25.9%를 차지하는 595mm이다. 깊은 침루량은 1,236.5mm로서 총강우량의 53.8%가 실험 유역 하부의 지하로 이동하며, 특히 우기인 여름철에는 깊은 침루율이 62.2%로 높아진다. 한반도 편마암 유역에 비하여 적어도 2배 이상 높은 실험 유역의 지하수 함양률은 투수성이 높은 제주도의 화산 지질 특성을 잘 반영하고 있다.

• 물과 미래
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• 제10권2호
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• pp.91-100
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• 1977

This is an experimental study to raise higher efficiency of filteration than conve ntional filteration by increasing of filteration capacity for per unit area and by extending of filteration lasting time with biflow filter system which was improved from the conventional rapid sand filteration method in the process of water purification treatment. In order to raise more efficient function of filteration and giving consideration to the filter layer at upper and lower parts of the filter, the fine sand & an thracite were used as a filter medium. Although there is some difficulty than previous fine sand in procurement, it could confirm that such filter medium (fine sand & anthracite) was more effective in the field of load, lasting time and back wash, etc. In consideration of practical effect of filteration. The raw water which was used for this experimental study was not coagulated. As a result of this experiment, the filteration volume could increase more than 2 times than that of conventional method. Besides, much more advantages could be obtained for instance, the requirement of installation area was not much and installation cost could economize. On the other hand, the following results were found. The quality of filtered water became worse as time goes by and the turbidity of filtered water was more influenced by raw water turbidity than by rate of filteration. Lasting time of filteration on change of filteration rate in the filter layer reached 2 times in comparison with previous filter basin, and until loss gead reached to 1.0 meter and 1.5 meter, the following relate formulas between lasting time and rate of filteration were formed. ($T_{1.5}=181.96V^{-0.46},\;T_{1.0}=121.31V^{-0.46}$) Even though the lasting time can be shorten in case of the increase of the filteration rate, but the lasting time was prolonged more than 2 times than of previous method. With taking aim at contribution to the development of water treatment technique, we are planning to study continuously for the future study basing on the results in this papers.

• 한국해양공학회지
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• 제21권2호
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• pp.67-74
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• 2007

Maritime and Ocean Engineering Research Institute (MOERI), a branch of KORDI, has designed and manufactured a model of an autonomous underwater vehicle (AUV) named ISiMI (Integrated Submergible for Intelligent Mission Implementation). ISiMI is an AUV platform to satisfy the various needs of experimental test required for development of challenging technologies newly investigated in the field of underwater robot; control and navigational algorithms and software architectures. The main design goal of ISiMI AUV is downsizing which will reduce substantially the operating cost compared to other vehicles previously developed in KORDI such as VORAM or DUSAUV. As a result of design and manufacturing process, ISiMI is implemented to be 1.2 m in length, 0.17 m in diameter and weigh 20 kg in air. A series of tank test is conducted to verify the basic functions of ISiMI in the Ocean Engineering Basin of MOERI, which includes manual control with R/F link, auto depth, auto heading control and a final approach control for underwater docking. This paper describes the implementation of ISiMI system and the experimental results to verify the function of ISiMI as a test-bed AUV platform.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.46-55
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• 2016

This experimental study was aimed to estimate interfacial tension of brine-$CO_2$ by using a pendant bubble method and image analysis. Measurements were performed for wide ranges of temperatures, pressures, and salinities covering reservoir conditions in Pohang basin, a possible candidate for $CO_2$ storage operation in Korea. The profiles of $CO_2$ bubbles in brine obtained from image analysis with the densities of brine and $CO_2$ from previous studies were applied to Laplace-Young equation for calculating interfacial twnsion in brine-$CO_2$ system. The experimental results reveals that the interfacial tension is significantly affected by reservoir conditions such as pressure, temperature and water salinity. For conditions of constant temperature and water salinity, the interfacial tension decreases as pressure increases for low pressures (P < $P_c$), and approaches to a constant value for high pressures. For conditions of constant pressure and water salinity, the interfacial tension increases as temperature increases for T < $T_c$, with an asymptotic trend towards a constant value for high temperatures. For conditions of constant pressure and temperature, the interfacial tension increases with increasing water salinity. The trends in changes of interfacial tension can be explained by the effects of the reservoir conditions on the density difference of brine and $CO_2$, and the solubility of $CO_2$ in brine. The information on interfacial tensions obtained from this research can be applied in predicting the migration and distribution of injecting and residual fluids in brine-$CO_2$-rock systems in deep geological environments during geological $CO_2$ sequestrations.