• 한국해양공학회지
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• 제22권4호
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• pp.78-83
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• 2008

In recent years, small boats used for marine leisure have been steadily increasing because of the increase in national income and the desire for marine leisure. But the repair of such small boats in dry dock has pointed out many faults in small FRP-shipbuilding in terms if workspace and manpower. Lifting a boat from the water to land is done with a crane or by hand using a sling around the bottom of the boat. But dry dock work is limited by the scale of the boat, which corresponds to the crane capacity, with carelessness making it possible to capsize a boat and endanger life. The purpose of this study was the development of a marine docking system that would improve economical efficiency and safety, for which we carried out concept design, model tests, structural analysis, etc.

• 한국농공학회논문집
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• 제56권5호
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• pp.67-75
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• 2014

In this study, the large-scale hydraulic model test was performed to investigate the hydraulic characteristics for development of the non-power soil cleaning and keeping system at the dike gate. The outlet height, outflow number, outflow discharge, and outflow cycle were compared and analyzed. The non-power soil cleaning and keeping system was most effective at 11.2 mm in the outlet height. And then the mean outflow cycle was 1.09 sec, and the mean outflow discharge was $0.00164m^3/s$. The total outflow number increased gradually as the water level of a water tank increased, and the outlet height decreased. As a level of water tank decreased, the mean outflow cycle was lengthened, and the unit outflow discharge increased. This result showed this system was most effective. To remove the silty clay deposited in facilities, the methods of excavation, dredging, high pressure washing, etc have been applied to the tidal facilities such as land reclamation, a small size fishing port, and a harbor for maintenance. However, this is extremely cost-ineffective, whereas the non-power soil cleaning and keeping system will bring about an enormously positive economic effect. In addition, when the non-power soil cleaning and keeping system is applied to the dike gate of land reclamation, a thorough examination of the local tidal data and the careful system planning are required to prevent the disaster damage caused by flooding.

• 한국해안·해양공학회논문집
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• 제20권2호
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• pp.232-237
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• 2008

소규모 수조를 이용한 조력발전시스템에 대하여 검토하였다. 이를 위하여 소규모 수조를 제작하고 시간에 따른 수위의 변화를 관측한 후 이를 이론적인 계산값과 비교하였다. 수조는 내부수조와 외부수조로 제작하여 창조발전과 낙조발전의 개념을 재현할 수 있도록 하였다. 또한 내부수조와 외부수조의 연결관을 두 곳에 설치하여 유량을 변화시키며 실험을 하였다. 관측된 수위의 변화를 계산값과 비교하여 유량계수를 산출하였다. 수위의 관측치와 이론적인 계산치는 높은 상관관계를 갖는 것으로 나타나 이론식이 실제의 수위를 잘 모의하는 것으로 나타났다. 프로펠러의 유무, 밸브의 유무, 창조 발전, 낙조 발전 등에 따라 유량계수가 큰 변화를 보이는 것으로 나타나 실제 발전시스템을 제작할 때 실험을 통한 유량계수 등의 산정이 반드시 필요한 것으로 나타났다. 또한 이론적인 식에 의한 총에너지와 실험유량으로부터 계산된 총에너지를 비교한 결과 큰 차이가 없는 것으로 나타났다. 본 수조에 대하여 계산된 발전량은 크지 않으나 충분한 조차가 있는 곳에 적정 규모의 수조를 설치할 경우 소규모의 조력발전이 가능하여 신재생에너지 생산에 기여할 것으로 판단된다.

• 지구물리와물리탐사
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• 제7권1호
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• pp.33-40
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• 2004

Numerical and laboratory studies have been conducted to test the ability of Electrical Resistance Tomography-a technique used to map the electrical resistivity of the subsurface-to delineate contaminant plumes. Two-dimensional numerical models were created to investigate survey design and resolution. Optimal survey design consisted of both downhole and surface electrode sites. Resolution models revealed that while the bulk fluid flow could be outlined, small-scale fingering effects could not be delineated. Laboratory experiments were conducted in a narrow glass tank to validate theoretical models. A visual comparison of fluid flow with ERT images also showed that, while the bulk fluid flow could be seen in most instances, fine-scale effects were indeterminate.

• 한국해양공학회지
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• 제13권1호통권31호
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• pp.130-137
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• 1999

The wing-flap stabilizing system attached under the hull bottom of a small fishing vessel to prevent the capsize by controlling the roll motions has been developed. This paper describes the background of the system design together with the experimental results. The effectiveness of the system is proven by the towing tank tests with a 1/4 scale model, showing that the roll motions of the model are much reduced by the active flap control in multidirectional irregular waves forward speeds.

• 한국축산시설환경학회지
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• 제12권3호
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• pp.151-160
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• 2006

For even distribution of liquid manure in the field, a boom nozzle type spreader was designed and studied to determined its suitability for small scale crop production farms. Boom nozzle type spreader was compared in the impact triple nozzle and impact single nozzle type spreader. Spreading uniformity of the boom nozzle type liquid manure spreader showed 5.2% (C.V.) and impact single nozzle type spreader showed 6.9% (C.V.). The spreading uniformity of the impact triple nozzle type spreader was quite uneven, therefore, the spreader could be modified as twin nozzle for spreading in orchard farm. The wheel axle height adjustable type liquid manure spreader has higher the stability and it considered much useful on the hilly agricultural land.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.125-128
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• 2000

본 연구에서는 순환식 돈분 폐수 처리 시스템에서의 미생물 분포에 따른 폐수 처리 효과를 모델링하기 위해 신경회로망과 PCA를 이용하는 새로운 방법을 제안하였다. PCA 분석 결과를 바탕으로 신경회로망의 최적 입력 조건을 찾고, 실측 데이터를 이용하여, 폐수 처리 시스템의 각 탱크를 별도로 학습함으로써 비교적 적은 수의 데이터에도 불구하고 정확한 모델링 결과를 얻었다. 제안한 시스템은 폐수 처리 시스템의 효과적인모니터링 시스템으로 사용할 수 있으며, 향후 실제 돈분 처리 시스템에서 원하는 기준의 방류수를 얻기 위한 최적의 입력조건 (미생물밀도 등)을 결정하는데 있어서 에뮬레이터로 사용될 수 있을 것으로 기대된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권5호
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• pp.355-361
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• 2000

A recycling reactor system operated under sequential anoxic and oxic conditions for the treatment of swine wastewater has been developed, in which piggery slurry is fermentatively and aerobically treated and then part of the effluent is recycled to the pigsty. This system significantly removes offensive smells (at both the pigsty and the treatment plant), BOD and others, and may be cost effective for small-scale farms. The most dominant heterotrophic were, in order, Alcaligenes faecalis, Brevundimonas diminuta and Streptococcus sp., while lactic acid bacteria were dominantly observed in the anoxic tank. We propose a novel monitoring system for a recycling piggery slurry treatment system through the use of neural networks. In this study, we tried to model the treatment process for each tank in the system (influent, fermentation, aeration, first sedimentation and fourth sedimentation tanks) based upon the population densities of the heterotrophic and lactic acid bacteria. Principal component analysis(PCA) was first applied to identify a relationship between input and output. The input would be microbial densities and the treatment parameters, such as population densities of heterotrophic and lactic acid bacteria, suspended solids(SS), COD, NH$_4$(sup)+-N, ortho-phosphorus (o-P), and total-phosphorus (T-P). then multi-layer neural networks were employed to model the treatment process for each tank. PCA filtration of the input data as microbial densities was found to facilitate the modeling procedure for the system monitoring even with a relatively lower number of imput. Neural network independently trained for each treatment tank and their subsequent combined data analysis allowed a successful prediction of the treatment system for at least two days.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권1호
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• pp.12-18
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• 2011

To investigate the natural reduction characteristics of radon with a short half-life (3.82 day) in drinking Qgroundwater, we analyzed the changes of radon concentrations of groundwater, waters in storage tanks, and tap waters from the small-scale groundwater-supply systems (N = 301) by LSC (Liquid Scintillation Counter). We also analyzed the concentrations of uranium (half-life 4.5 billion years) in the waters by ICP/MS to compare with natural reduction of radon concentration. The radon concentrations of 68 groundwater-supply systems occupying 22.6% of the total samples exceeded the US EPA's Alternative Maximum Contaminant Level (AMCL : 4,000 pCi/L), with the average radon concentration of 7,316 pCi/L (groundwaters), 3,833 pCi/L (tank waters) and 3,407 pCi/L (tap waters). Compared to the radon levels of pumped groundwaters, those of tank and tap waters naturally reduced significantly down to about 50%. Especially, in case of 29 groundwater-supply systems with the groundwater radon concentrations of 4,000~6,000 pCi/L, average radon concentrations of the tank and tap waters naturally decreased down to the AMCL. Therefore this study implies that radon concentrations of drinking groundwater can be effectively reduced by sufficient storage and residence in tanks.

• 한국수산과학회지
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• 제35권3호
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• pp.302-307
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• 2002

멸치액젓을 소규모 및 대규모 탱크로 나누어 재래식 방법으로 제조하여 실온 ($15\~24^{\circ}C$)에서 18개월 동안 숙성시키면서 2-3개월 간격으로 식품 성분변화에 대하여 조사하였다. 소규모 및 대규모 탱크 멸치액젓 모두 총질소 및 아미노산성 질소함량, 그리고 ATP 관련물질 총량은 숙성기간에 비례하여 일정하게 증가하였으며, 숙성 6개월 후에는 발효조 크기에 따른 상대적 효소량의 차이로 인해 대규모 탱크 멸치액젓이 소규모 탱크 멸치액젓보다 육의분해속도가 빨라 큰 함량의 차이를 보였지만, 숙성기간이 길어짐에 따라 효소활성의 저하로 18개월 후에는 함량의 차이가 적어졌다. 요산은 원료육에서는 나타나지 랴았지만, 소규모 탱크 멸치액젓은 숙성 8개월 후부터, 대규모 탱크 멸치액젓은 숙성 7개월 후부터 액젓의 ATP 관련물질 중에서 가장 많은 양을 차지하고 있었다 HXR+HX 함량과 요산량이 교차하는 숙성 12.6개월 (소규모 탱크 멸치액젓)과 10.3개월 (대규모 탱크 멸치액젓) 부근은 가용화율이 각각 $73\%$ 및 $76\%$로 높은 분해율을 보이는 지점이었고, 관능적인 맛과 냄새면에서도 우수한 것으로 나타나 숙성 최적지점인 것으로 추정된다. 18개월간 숙성시킨 소규모 탱크 멸치액젓의 유리아미노산 총량은 8,769.7mg/100mL으로 대규모 탱크 멸치액젓 함량 (9,983.3 mg/100mL)의 $88\%$ 정도였다. 유리아미노산 중 glutamic acid는 숙성기간에 따라 가장 큰 폭으로 증가하여 18개월 후에는 소규모 탱크 멸치액젓에서 그 조성비가 $20\%$인 1,750.3m조100 mL, 대규모 탱크 멸치 액젓에서는 $21\%$인 2,100.3 mg/100 mL으로 가장 높았으며, 그 다음이 소규모 탱크 멸치액젓에서는 aspartic acid ($12.0\%$), alanine ($9.4\%$), Iysine ($8.9\%$), valine ($7.4\%$) 순이었고, 대규모 탱크 멸치액젓에서는 alanine ($12.6\%$), aspartic acid ($11.9\%$), valine ($6.3\%$), Iysine ($6.2\%$) 등의 순으로 주요 아미노산의 종류는 같지만 조성순이 달랐다. 그리고, 액젓의 색도는 대규모 탱크 멸치액젓이 소규모 탱크 멸치액젓보다 숙성기간을 통하여 그 값이 높았다