This study was conducted to investigate the proper design of alpha board used to support concrete blocks under high loads. A board height of 50 mm was appropriate to ensure a deflection of 3 mm or less under a load of 5 tons. The trapezoidal shape of the vibration absorbers in the interior of the board reduced the maximum deflection by evenly distributing the deflection across the board width. The height of the board is the most important variable in preventing deflection, and for the same board height, adjusting the thickness of the top and bottom plates was more effective in reducing the amount of deflection than adjusting the thickness of the stiffener. The theoretical solution is a good tool for easily predicting the deflection of the board, as it shows a difference of 5 to 15% from the simulation results. However, as a 2D prediction model, the theoretical solution cannot represent the distribution of deflection over the entire board area, so the 3D simulations are necessary in predicting the amount of deflection over the entire board.

선박이 부두에 안전하게 계류 및 예인하기 위해서는 관련 국제규정에 부합하는 설계를 해야 한다. 그러나 현재까지도 일부 소 형 조선소 및 설계 회사에서는 그 내용을 정확히 숙지하지 못하고 있는 경우가 많다. 따라서 본 논문에서는 예인 및 계류설비에 관한 국 제규정을 살펴보고, 최신 발효된 MEG4(Mooring equipment guideline 4) 기준에 만족하는 대표적인 계류 의장품인 볼라드(Bollard)와 쵸크 (Chock)를 개발하고자 한다. 볼라드는 계류 밧줄을 선체에 고박하기 위한 의장품이며, 일반적으로 2개의 기둥으로, 대부분은 8자 매듭 형 태로 사용하고 있다. 쵸크는 선외에서 선내로 들어오는 계류 밧줄의 방향을 전환하고, 밧줄의 손상을 방지하기 위하여 곡률을 갖는 주물 방식으로 제작한다. 이 두 가지 계류 의장품은 선박의 선수와 선미, 중앙부 측면에서 많이 사용되고 있다. 최근 컨테이너선 및 LNG 운반 선의 크기 증가로 인하여, 계류 밧줄 하중이 증가하고 있으며, 계류 의장품도 안전사용하중(Safe working load)이 변경되어야 한다. 본 연구 에서는 유한요소해석 모델링을 통한 허용응력 평가법 결과를 정리하고, 분석하였다. 추가적으로 비선형 붕괴 거동 평가를 통하여, 안전사 용하중 결정에 대한 검증을 수행하였고, 탄성영역 내 설계가 되었음을 확인하였다. 연구에서 제안하는 평가법 및 기준, 그리고 해석절차 는 향후 유사 의장품 개발 시 참조가 가능하다.

The change in pressure measurement according to the low pressure tap blockage rate of the Venturi flowmeter used in domestic nuclear power plants was approached numerically. Blockage rates were modeled dividing by 1/10dT to the downstream side of the low pressure tab to identify differential pressure changes. As a result, differential pressure increased in proportion to the blockage rate, and there was no change in differential pressure measurement at 10 to 40 percent with relatively small blockage rate, but the error rate of 50% to 0.3% or higher was shown.

Anomaly detection of Machine Learning such as PCA anomaly detection and CNN image classification has been focused on cross-sectional data. In this paper, two approaches has been suggested to apply ML techniques for identifying the failure time of big time series data. PCA anomaly detection to identify time rows as normal or abnormal was suggested by converting subjects identification problem to time domain. CNN image classification was suggested to identify the failure time by re-structuring of time series data, which computed the correlation matrix of one minute data and converted to tiff image format. Also, LASSO, one of feature selection methods, was applied to select the most affecting variables which could identify the failure status. For the empirical study, time series data was collected in seconds from a power generator of 214 components for 25 minutes including 20 minutes before the failure time. The failure time was predicted and detected 9 minutes 17 seconds before the failure time by PCA anomaly detection, but was not detected by the combination of LASSO and PCA because the target variable was binary variable which was assigned on the base of the failure time. CNN image classification with the train data of 10 normal status image and 5 failure status images detected just one minute before.

수입감자의 세척수에 존재할 수 있는 선충을 박멸하기 위하여 선박 평형수 소독에 활용되는 미세필터와 고준위의자외선 시스템을 활용하였다. 우선 미세필터(지름이 다른 4겹의 필터, 최저직경 17㎛)에 대한 뿌리혹선충의 통과여부를조사해 본 결과 유충(체폭 10.7-23.2㎛)은 통과했지만 난낭(직경 300-1,000㎛)은 통과되지 않았다. 자외선 조사에대한 선충의 사멸효과를 분석해 본 결과 유충과 알은 200 mJ/cm2 이상 처리시에 100% 살충이 되었으나 난낭속의알은 1,080 mJ/cm2처리에도 일부 부화했다. 현장적용시험에서 150톤의 세척수에 약 10만마리유충을 투여하고1,663±174 mJ/cm2의 UV 처리한 결과 생존된 선충이 검출되지 않았다. 즉, 고준위의 자외선 조사 시스템은 대용량의세척수에서 선충을 사멸하는데 적용될 수 있다. 그리고, 필터에 걸러진 난낭을 포함한 소량의 물을 소독하기 위하여열처리 시스템(50℃, 15분)을 적용함으로서 검역수준의 선충사멸효과를 얻을 수 있다고 판단된다.

Quality changes of carrots thermally processed in a large size (5 kg) retort pouch during 52 weeks of storage were investigated under different packaging methods and package shapes. To improve the efficiency of thermal processing (121.1oC, 0.15 MPa), the carrot (i.e., solid) and the broth (i.e., liquid) of the carrot soup were separately packed and sterilized. The quality changes of carrot packed without liquid were compared with those with liquid. Two different package shapes such as rectangular parallelepiped and cube were also evaluated to figure out the efficiency of the heat penetration rate for a large-sized pouch. The TTT (F0-values = 6) were 27, 54, and 114 min from the rectangular parallelepiped, cube, and solid/liquid mixed groups, respectively. In the mixed groups, the hardness and chewiness of solids (carrot) were significantly smaller than those measured in the other groups as TTT increased. Carrots treated in the rectangular parallelepiped shape showed a significantly higher texture than the cube shape. The CV of hardness and chewiness in the rectangular parallelepiped and the cube shape were calculated as 7.56 and 47.19, and 29.16 and 65.28, respectively. This demonstrated that a more uniform quality can be obtained from the rectangular parallelepiped shape.

The finite element stress analysis of large sized rectangular water tank structures made of stainless steel materials is carried out for various combined load cases. The combined load cases for a large size of 5,000ton are further determined using the specification(KS B　6283) established from the Korean Standards Association. The changed water capacity due to the size of reservoirs could be heavily dependent for evaluating seismic effects, especially for large reservoirs. For the better numerical efficiency, the rectangular panels are modelled using the ANSYS ADPL module. The numerical results obtained for different load cases mainly show the effect of the interactions between the different load combination and other various parameters, for example, the water capacity, and different stainless steel materials. The structural performance for various load combinations is also evaluated.