• 대한조선학회논문집
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• 제35권2호
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• pp.38-50
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• 1998

부유식 방파제의 특성을 파악하기 위하여 수면 근처에 고정된 상자형 방파제 경우의 방파성능을 실험하고 수치계산과 비교하였다. 상자의 폭과 흘수를 변화시키고 파의 주기와 경사도(wave steepness)를 변화시킴으로써 비교적 다양한 변수변화에 따른 영향을 확인하고자 하였다. 투과계수와 방파제에 작용하는 힘을 실험으로부터 측정하고 선형포텐셜이론에 의해 계산된 결과와 비교함으로써 방파제가 수면근처에 고정된 경우 투과계수와 파력에 대한 흘수 및 파장의 영향을 논하였다. 배열의 경우 폰툰사이의 간격이 투과계수와 파력에 미치는 효과를 논하였고, 전반적으로 계산이 실험의 결과를 효과적으로 예측할 수 있음을 확인하였다.

• 한국해양공학회지
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• 제21권4호
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• pp.1-7
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• 2007

Based on the eigenfunction expansion method, the wave-absorbing performance of a square or circular pile breakwater was investigated. Flow separation resulting from sudden contraction and expansion is generated and is the main cause of significant energy loss. Therefore, evaluation of an exact energy loss coefficient is critical to enhancing the reliability of the mathematical model. To obtain the energy loss coefficient, 2-dimensional turbulent flow is analyzed using the FLUENT commercial code, and the energy loss coefficient can be obtained from the pressure difference between upstream and downstream. It was found that energy loss coefficient of circular pile is 20% that of a square pile. To validate the fitting equation for the energy loss coefficient, comparison between the analytical results and the experimental results (Kakuno and Liu, 1993) was made for square and circular piles with good agreement. The array of square piles also provides better wave-absorbing efficiency than the circular piles, and the optimal porosity value is near P=0.1.

• 한국해양공학회지
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• 제31권5호
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• pp.325-334
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• 2017

This paper reports the conceptual design process for a floating metocean data measurement system (FMDMS) for measuring wind information at sea. The FMDMS consists of three circular pontoons, columns, and a deck, which the LiDAR (lighting detection and ranging) is installed on. The dynamics of the mooring lines and motion responses of the FMDMS were analyzed using commercial codes such as WAMIT and OrcaFlex. One design criterion of the developed FMDMS was to maintain the motion responses as small as possible to enhance the LiDAR's accuracy. Starting with the preliminary design parameters such as the FMDMS's principal dimensions, weight, and important parameters of mooring system, we checked whether the FMDMS met the design requirements at each design stage, and then made modifications as necessary. The developed FMDMS showed a large pitch behavior for a small heave motion.

• 한국환경보건학회지
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• 제32권1호
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• pp.89-95
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• 2006

This study was conducted to improve an effect of phosphorus removal using FNR(Ferrous Nutrient Removal) process which had iron precipitation reactor and to analyze the iron corrosion. For simultaneous removal of phosphorus, iron electrolysis was combined with oxic tank. In this study, The removal efficiency of phosphorus increased with an increase voltage in iron precipitation reactor. The distance of 15mm between the two iron bed in each tests influence the concentration of remaining phosphorus most. The extensive surface area of iron bed is the more removes the phosphorus. In this test the $400\;cm^2$ of surface area was proved to be the most removal efficient.

• 환경영향평가
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• 제12권3호
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• pp.211-228
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• 2003

Most environmental impact assessment(EIA) programs around the world require the consideration of human health impacts. Yet relatively few EIA documents adequately address those impacts. This article examines how, why, and to what extent health impacts are analyzed in environmental impact assessments. This article investigates these problems and provides recommendations to improve human health impact assessment(HIA), using methods, procedures and case study. Also, a comprehensive approach for the evaluation of possible health effects in an EIA is described, illustrated with the example of Amsterdam Airport Schiphol. Unlike many EIAs, we estimated quantitatively the impact of aircraft-related pollution in terms of the number of affected people for aircraft noise annoyance, odour annoyance and hypertension. In addition, an analysis of health registry data on cardiovascular and respiratory diseases and a short survey on annoyance and risk perception were carried out.

• 한국해양공학회지
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• 제25권6호
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• pp.9-16
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• 2011

The feasibility of wave energy extraction from a heaving truncated cylinder and the corresponding response of the linear electric generator (LEG) composed of spring, magnet, and coil has been investigated in the frame of three-dimensional linear potential theory. The heaving motion of a circular cylinder is calculated by means of the matched eigenfunction expansion method. Further, the analytical results are validated by numerical results using the ANSYS AQWA commercial code. By the action of a heaving circular cylinder, the magnet suspended by a spring can slide vertically inside the heaving cylinder. The mechanical power is extracted from the magnet motion relative to the coil/stator which is attached to the cylinder. The coupled ODE of a heaving cylinder and LEG system in waves is derived to obtain the magnet motion relative to a cylinder. To maximize the relative motion of the magnet, both the buoy draft and the LEG system parameters (spring stiffness, damping) should be selected properly for generating the double resonance considering the peak frequency of the target spectrum.

• 한국환경보건학회지
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• 제26권3호
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• pp.61-68
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• 2000

The use of photo-catalytic processes in pollution abatement and resource has a significant economic importance. Therefore, the applications of photochemical oxidation of secondary effluent driven by UV, TiO2, TiO2/UV, H2O2/UV and TiO2/H2O2/UV, have been investigated in order to treat the secondary effluent from municipal sewage. Various experimental parameters such as BOD, CODcr, Nurbidity, total P, and SPC were examined in each photo-catalytic reaction system. The results showed that the application of single oxidant such as UV, TiO2 only has a minor effect on parameters reduction (CODcr, BOD, etc) to treat the secondary effluent, whereas the combinations of oxidants increase the removal efficiency. The best removal efficiency in every parameters was achieved by the combination of TiO2, H2O2 and UV. It was also found that the optimum amount of TiO2 for the treatment was 1g/ι to achieve water reuse standard. From the results, the photocatalytic reaction system can be an alternative as a post-treatment to treat the secondary effluent from municipal sewage.

• 한국환경보건학회지
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• 제26권3호
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• pp.69-75
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• 2000

This study was carried out to investigate the removal of nitrogen and phosphorus in municipal sewage according to the variation of volumetric ratio in the reactor. It also was performed to provide basic data necessary to the development and improvement of the process which is Anaerobic-Anoxic-Oxic(A2O). In the removal of BOD and COD, the best efficiency of the process showed in the condition of using the media, 1Q of internal recycle rate and 1:3:2 of the volumetric ratio in Anaerobic-Anoxic-Oxic process. In most cases, nitrogen and phosphorus removal efficiency of the process using the cilia media was superior to that of the process which didn't use the media. In the removal of T-N and T-P, the best efficiency of the process showed in the condition of using the media, 1Q of internal recycle rate and 1:3:2 of the volumetric ratio in Anaerobic-Anoxic-Oxic process.

• 한국실내디자인학회논문집
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• 제16권1호
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• pp.65-72
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• 2007

Various residential patterns, which can accommodate ever-changing modem lifestyles, are increasingly needed. On the residents' demand for flexible space, mote research should be conducted on the apartments built by the concept of flexible space. In this study, apartments of 40-60 pyeong in size built in the region of Seoul, between 1998 and 2007, are analyzed in terms of the flexible types and the unit plan composition. To reflect the changes in people's perception of residential quality-preference for a residence with a good view, over for the direction that a residence faces, more rooms are placed on the front bay. From the analyses of this study, flexible unit plans are classified into 6 types; and it was found that, as the size of apartments gets larger, the livingroom and the dinning room tend to be placed on the front bay. After grouping rooms with a similar function into the spatial zones of the master bedroom, children's room, the livingroom, and the dinning room, flexible types are analyzed in terms of the location of rooms. The results of this study will be able to contribute to establishing flexible housing culture that can accommodate the changing needs of residents.

• 한국해안해양공학회지
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• 제15권3호
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• pp.143-150
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• 2003

고유함수전개법을 사용하여 수직벽 앞에 일정깊이 잠긴 슬릿판과 규칙파의 상호작용문제를 살펴보았다. 슬릿판에 의한 반사율에 영향을 미치는 주요 설계변수들은 공극율, 잠긴깊이, 챔버길이, 입사각도, 입사파의 주파수임을 확인하였다 슬릿판의 공극율이 0.1일 때 반사율이 전주파수에 걸쳐서 최소가 됨을 밝혔다. 반사율에 대한 해석결과와 Zhu(2001) 모형실험결과를 챔버길이와 잠긴깊이 그리고 입사파의 주기를 변화시키면서 비교한 결과, 두 결과는 서로 잘 일치하였다. 본 해석방법은 슬릿판 후면에서 발생한 박리에 의한 에너지 손실을 정확히 고려할 수 있으므로 슬릿 케이슨 방파제 제작에 필요한 설계정보를 제공할 것이다.