• 한국유기농업학회지
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• 제29권3호
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• pp.317-332
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• 2021

This study estimated the predictive onion yield through Stepwise regression of big data and weather variables by onion growing season. The economic feasibility of onion observations using big data was analyzed using estimated predictive data. The social welfare effect was estimated through the model of Harberger's triangle using onion yield prediction with big data and it without big data. Predicted yield using big data showed a deviation of -9.0% to 4.2%. As a result of estimating the social welfare effect, the average annual value was 23.3 billion won. The average annual value of social welfare effects if big data was not used was measured at 22.4 billion won. Therefore, it was estimated that the difference between the social welfare effect when the prediction using big data was used and when it was not was about 950 million won. When these results are applied to items other than onion items, the effect will be greater. It is judged that it can be used as basic data to prove the justification of the agricultural observation project. However, since the simple Harberger's triangle theory has the limitation of oversimplifying reality, it is necessary to evaluate the economic value through various methods such as measuring the effect of agricultural observation under a more realistic rational expectation hypothesis in future studies.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권6호
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• pp.17-25
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• 2007

투수성이 높고 대수층의 저유량이 풍부한 강변여과수 개발 예정지역의 충적층에서 시험규모가 2m (IW-1공와 5m (IW-2공)인 경우의 수렴흐름 추적자시험이 수행되었다. 수렴흐름 추적자시험의 양수율은 $2,500m^3/day$ 이었으며, 주입정 (IW-1 및 IW-2공)에 염소이온 5kg을 순간 주입하였다. 염소이온의 농도이력곡선을 작성하여 초기도달시간과 최고농도의 차이를 분석하였으며, 누적질량회수곡선을 통해 양수 후 경과시간에 따른 염소이온의 질량회수율을 분석하였다. 그리고, 염소이온농도 대 누적질량회수율의 이력그래프를 작성하여 누적질량회수율에 따른 염소이온농도의 증가와 감소 변화를 분석하였다. 또한, 염소이온농도의 증가/감소 구간에 대한 선형회귀분석을 수행하여 농도증가율과 감소율의 변화를 파악하였다. 양수정에서 관측된 경과시간별 염소이온농도 자료를 CATTl 코드의 quot;Converging Radial Flow With Instantaneous Injectionquot; 해석법에 적용하여 종분산지수를 추정하였다. 추정된 종분산지수는 양수정과 IW-1공 사이의 충적층에서는 0.4152 m, 양수정과 IW-2공 사이의 충적층에서는 3.2665 m이었다. 양수정에서 이격거리가 멀수록 종분산지수는 증가하였으며, 이격거리에 대한 종분산지수의 비는 각각 0.21과 0.65 정도이었다.

• 전기의세계
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• 제22권2호
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• pp.70-74
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• 1973

This paper dealt with circuit modeling of SCR and gate turn-off SCR by using complementary symmetrical tansistor circuit, which is modified circuit of input current dependent, current stable negative resitance circuit. Operation of this circuit is estimated and analyzed, with which compared with conventional SCR modeling circuit. Also operation and the design procedures are checked by experiments.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.122-125
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• 2006

The distribution of phytoplankton pigments were studied bimonthly at four stations from the mouth of Mahanadi River at Paradip to the 36.7km off coast in Bay of Bengal during April 2001 to December 2002. Bottom depth was shallower than 40m in all stations. The pigment concentration of Chl-a was measured. It increased from surface to bottom in the water column. The water column integrated chlorophyll-a concentration (Chl-a) varied between 6.1 and $48.5mg{\cdot}m-^2$ with peaks during monsoon period (Aug & Oct). Spatial distribution of salinity depended strongly on freshwater runoff. The salinity was 5psu at river mouth and 25.15psu at offshore in monsoon period; however it was 30psu at the river mouth in summer. We found a linear relationship between the amount of river discharge and integrated Chl-a in coastal region from 2 years observations. Extending this result, we analyzed rainfall and coastal Chl-a using satellite data. The relationship between the river discharge and monthly accumulated rainfall estimated from TRMM and others data sources was analyzed in 2001 and 2002 using Giovanni infrastructure provided by NASA. The result depended on the specified area on TRMM images; the river delta area had sharper relationship than wider rain catchments area. Moreover, the relationship between monthly averaged Chl-a derived from SeaWiFS and monthly accumulated rainfall estimated from TRMM was analyzed from 1998 to 2005. It was clear that the broom in monsoon period was strongly controlled by rainfall on river delta.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.994-995
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• 2014

Supporting stiffness of seats is an important component affecting dynamic characteristics cognized by a passenger. To analyze dynamic characteristic of a seat for vehicles operating on various road conditions, the seat vibration from road irregularity should be understood and compared. In this study, the seat is analyzed as distributed supporting system. The dynamic stiffness is measured using masses. The characteristic of the seats is analyzed by measuring distributed dynamic stiffness. The distributed dynamic stiffness of the seat is estimated on various locations and the effects of each component such as spatial distribution, compression level and vibration amplitude are analyzed. The influence of seat cover, elastic support and flexible polyurethane foam on the measured stiffness was analyzed.

• 한방재활의학과학회지
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• 제24권3호
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• pp.149-155
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• 2014

Objectives This study was designed to investigate the correlation between the difference of pelvic height and difference of gait balance. Methods 62 cases of patients who received treatment from January 2011 to March 2014 for abnormal postures were analyzed. Their difference of pelvic height were estimated by whole spine X-ray analysis and gait balance were estimated by Treadmill Gait Analysis system. The data were analyzed to find out correlation between difference of pelvic height and difference of gait balance, and correlation between the position of pelvic tilt and gait balance higher side. Pearson correlation and Chi-square analysis were used. Results Pelvic height heigher side were more left than right side, and gait balance higher side were also more left than right side. Difference of pelvic height and difference of gait balance had a positive linear relationship, but there was no significant correlation. The position of pelvic tilt had significant correlation with gait balance higher side. Conclusions The position of pelvic tilt had significant correlation with gait balance higher side and difference of pelvic height had no significant correlation with difference of gait balance.

• 수산경영론집
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• 제42권3호
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• pp.1-13
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• 2011

It is necessary to set up a standard of estimation for annual unit price of sale and cost, damage rate for calculating compensation against fishery damage objectively. Two items on the unit price and cost have regulations but the damage rate has not, so it may occurred some problems such as reasonability and balance because the estimation should be handling by an appraiser's knowledge and experience. This study has analyzed using Regression model and searched variable costs and fixed costs about each items appraisers to operate in the present. It is compare profit damage index is calculated by an estimated model and an appraised example. This analysis showed highly 23-30% estimated model more than appraised example. It means the overestimation for fishery damage. This difference has caused by limited data, lack of sample, much difference in the standard deviation, and has not classified each kind of business and weight of coastal fishery, the overestimation more than what expected. This study has analyzed that the applied rate of fixed and variable cost in relation to the compensation in the cost of coastal fishery is very valuable.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.1-10
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• 2012

In this study, global positioning system (GPS)-derived precipitable water vapor (PWV) and microwave radiometer (MWR)-measured integrated water vapor (IWV) were compared and their characteristics were analyzed. Comparing those two quantities for two years from August 2009, we found that GPS PWV estimates were larger than MWR IWV. The average difference over the entire test period was 1.1 mm and the standard deviation was 1.2 mm. When the discrepancies between GPS PWV and MWR IWV were analyzed depending on season, the average difference was 0.7 mm and 1.9 mm in the winter and summer months, respectively. Thus, the average difference was about 2.5 times larger in summer than that in winter. However, MWR IWV measurements in the winter months were over-estimated than those in the summer months as the water vapor content got larger. The results of the diurnal analysis showed that MWR IWV was underestimated in the daytime, showing a difference of 0.8 mm. In the early morning hours, MWR IWV has a tendency to be over-estimated, with a difference of 1.3 mm with respect to GPS PWV.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1206-1210
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• 2005

This paper presents performance improvement in optical CDMA system under the presence of beat noise using a cancellation technique. Optical fibers and atmospheric optical communications have been proposed the connection between base stations and central station. The optical signal beat noise is due to interference between lightwave, many optical waves are simultaneously incident on each receiver photodiode. Since the photodiode acts as a square-law detector, beat noise can occur in the receiver. While A two-stage cancellation technique is analyzed and verified via simulation employed here because of its system simplicity. By using the random ingredients of all user signals are estimated, the beat noise is rebuilt and removed from the intended signal. In addition to cancellation technique cancel the inherent multiuser interference (MUI) in CDMA system and nonlinear distortion (NLD) in optical system. It is performed at the receiver of the central station where the random ingredients of all user signals are estimated and the MUI and the NLD are rebuilt and removed from the received signal. The validity of the cancellation technique is theoretically analyzed and shown by numerical results. The increasing of capacity in two stage cancellation are obtained.

• International Journal of Railway
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• 제5권1호
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• pp.10-21
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• 2012

Open steel plate girder (OPSG) bridges are the most prevalent railroad bridge type in Korea, constituting about 40% of all railroad bridges. Solid steel bearings, known as line type bearings, are placed in most OSPG railway bridges. However, the line type rigid bearings generate several problems with the bridge's dynamic behavior and maintenance in service. To compare and investigate the dynamic behaviors of line type, spherical and disk bearings, the vertical displacements of each bearing, including fixed and expansion type, under running vehicles are measured and analyzed. The displacements of disk and spherical bearings are measured after replacing the line type bearings with spherical and disk bearings. This study also analyzed dynamic behaviors of bridges. Furthermore, the deformation of the PTFE (Polytetrafluoroethylene) plate that is placed inside of expansion type spherical and disk bearings is measured and its effect on the dynamic behavior of the bridges is discussed. The up-lift phenomenon at the bearings installed for the steel bridges is estimated. The vertical displacements at mid-span of the bridges are compared according to the bearing types. Finally, the 1st mode natural frequencies are estimated, and the relationship to the vertical displacement is discussed.