• 제목/요약/키워드: deep layer mean and layer mean

검색결과 83건 처리시간 0.027초

벼의 자연통풍건조에 있어서 통풍량이 건조에 미치는 영향에 관한 연구 (A Study on Effects of Air-delivery Rate upon Drying Rough Rice with Unheated Air.)

  • 이상우;정창주
    • 한국농공학회지
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    • 제16권1호
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    • pp.3293-3301
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    • 1974
  • An experimental work was conducted by using a laboratory-made model dryer to investigate the effect of the rate of natural forced-air on the drying rate of rough rice which was deposited in the deep-bed. The dryer consisted of 8 cylinderical containers with grain holding screen at their bottoms, each of which having 30cm in diameter and 15cm in height. The containers were sacked vertically with keeping them air-tight by using paper tape during dryer operation. Two separate layers of containers were operated in the same time to have two replications. The moisture contents of grains within each bins after predetermined period of dryer operation were determined indirectly by measuring the weight of the individual containers. The air-rates were maintained at 6 levels, or 5, 8, 10, 15, 18 and 20 millimenters of static head of water. The roomair conditions during dryer operation were maintained in the range of 10-l5$^{\circ}C$ in temperature and 40-60% in relative humidity. The results of the study are summarized as follows: 1. Drying characteristics of the grains in the bottom layers were approximately the same regardless of airdelivery rates, giving the average drying rate as about 0.35 percent per hour after 40-hour drying period, during which moisture content (w. b.) reduced from 24 percent to about 10 percent. 2. After about 40-hour drying period, the mean drying rates increased from 0.163 percent per hour to 0.263 percent per hour as air-flow rates increased from 5mm to 87.16mm of static head of water. In the same time, the moisture differences of grains between lower and upper layers varied from 12.7 percent at the air rate of 5mm of water head to 7.5 percent at the air-flow rate of 20mn of water head. Thus, the greater the air-flow rate was, the more overall improvement in drying performance was. Additionally, from the result of ineffectiveness of drying grain positioned at 70cm depth or above by the air rate of 5mm of static head of water it may be suggested in practical application that the height of grain deposit would be maintained adequately within the limits of air-rates that may be actually delivered. 3. Drying after layer-turning operation was continued for about 30 hours to test the effectiveness of reducing moisture differences in the thick layers. As a result of this layer-turning operation, moisture distribution through layers approached to narrow ranges, giving the moisture range as about 7 percent at air-flow rate of 5mm head of water, about 3 percent at 10mm head about 2 percent at 15mm head, and less than 1 percent at 20mm head. In addition, from the desirable results that drying rate was rapid in the lower layers and dully in the upper layers, layer-turning operation may be very effective in natural air drying with deep-layer grain deposit, especially when the forced air was kept in low rate. 4. Even though the high rate of air delivery is very desirable for deep-layer natural-air drying of rough rice, it can be happened that the required air delivery rate could not be attained because of limitation of power source available on farms. To give a guide line for the practical application, the power required to perform the drying with the specified air rate was analyzed for different sizes of drying bin and is given in Table (5). If a farmer selects a motor of which size is 1 or {{{{1 { 1} over {2 } }}}} H.P. and air-delivery rate which ranges from 8~10mm of head, the diameter of grain bin may be suggested to choose about 2.4m, also power tiller or other moderate size of prime motor may be recommended when the diameter of grain bin is about 5.0m or more for about 120cm grain deposit.

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Application of CE-QUAL-W2 [v3.2] to Andong Reservoir: Part I: Simulations of Hydro-thermal Dynamics, Dissolved Oxygen and Density Current

  • Bhattarai, Prasid Ram;Kim, Yoon-Hee;Heo, Woo-Myoung
    • 생태와환경
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    • 제41권2호
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    • pp.247-263
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    • 2008
  • A two-dimensional (2D) reservoir hydrodynamics and water quality model, CE-QUAL-W2, is employed to simulate the hydrothermal behavior and density current regime in Andong Reservoir. Observed data used for model forcing and calibration includes: surface water level, water temperature, dissolved oxygen and suspended solids concentration. The model was calibrated to the year of 2003 and verified with continuous run from 2000 till 2004. Without major adjustments, the model accurately simulated surface water levels including the events of large storm. Deep-water reservoirs, like Andong Reservoir, located in the Asian Monsoon region begin to stratify in summer and overturn in fall. This mixing pattern as well as the descending thermocline, onset and duration of stratification and timing of turnover phenomenon were well reproduced by the Andong Model. The temperature field and distinct thermocline are simulated to within $2^{\circ}C$ of observed data. The model performed well in simulating not only the dissolved oxygen profiles but also the metalimnetic dissolved minima phenomenon, a common1y occurring phenomenon in deep reservoirs of temperate regions. The Root Mean Square Error (RMSE) values of model calibration for surface water elevation, temperature and dissolved oxygen were 0.0095 m, $1.82^{\circ}C$, and $1.13\;mg\;L^{-1}$, respectively. The turbid storm runoff, during the summer monsoon, formed an intermediate layer of about 15 m thickness, moved along the metalimnion until being finally discharged from the dam. This mode of transport of density current, a common characteristic of various other large reservoirs in the Asian summer monsoon region, was well tracked by the model.

동해남부 대마난류계에서의 염소화 Biphenyls의 분포특성 (Distribution Chara Cteristics of Polychlorinated Biphenyls in the Southern Korea)

  • 이동인;옥곤;양한섭;장윤석
    • 한국수산과학회지
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    • 제30권4호
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    • pp.679-686
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    • 1997
  • 본 연구조사는 동해남부 대마난류계에서의 PCBs의 분포특성을 파악하기 위하여 1996년 8월과 10월에 걸쳐 5개 정점을 선정하여 각 정점의 수심별의 수온, 염분 및 용존산소를 측정하여 수괴 분석을 실시하였으며, 또한, 각 정점별, 수심별의 PCBs의 분석을 실시하였다. 수괴의 분포특성을 조사한 결과 수온 및 염분약층은 수심 30m부분에 존재하고 있었으며, 대마난류 중층수는 30m이하로 간주되었으며, 대마난류의 표층수는 한국근해에서 대마도쪽으로 확장되는 양상을 보였다. PCBs의 분석결과 표층수는 8월의 경우 대마도쪽으로 갈수록 농도가 약간 낮아지는 경향을 보이다가, 대마도쪽에서 다시 약간의 증가경향이 관찰되었다. 표층 해수중에서의 PCBs의 평균농도는 $0.29\;ng/\ell$정도 였으며, 중층에서의 평균농도는 $0.31\;ng/\ell$정도로 표층에 비교하여 중층에서의 농도가 약간 증가하는 것으로 나타났다. 해수중 PCBs의 농도는 부유물질의 농도변화 경향과 유사성을 나타났으며, 농도의 수평 및 연직변화는 그다지 크게 나타나지 않아 비교적 균일한 농도분포를 나타내고 있었다. 해수의 수심별 PCBs의 상대농도 조성비는 표층에서 Di- 및 Tri-PCBs의 비율이 높았지만, 심층으로 갈수록 Peta-PCBs의 상대농도 조성비율이 높은 것으로 나타나, 수심의 변화에 따른 PCBs의 구성비와 소실에 차이가 있는 것으로 사료된다.

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대한해협 서수도 냉수의 구조와 역학 (Structure and Dynamics of the Cold Water in the Western Channel of the Korea Strait)

  • 조양기;김구;김영규
    • 한국해안해양공학회지
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    • 제9권3호
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    • pp.132-139
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    • 1997
  • 대한해협 서수도 깊은 골의 냉수구조를 파악하기 위하여 1993년 10월에 해수물성 조사와 해류관측을 실시하였다. 냉수의 두께는 20-70 m로 수심에 따라 다르다. 냉수와 대마난류 사이의 수온약층은 남쪽으로 향할수록 깊어지며, 기울기는 약 0.00057이다. 냉수 두께의 시간적 변화는 조류와 관련이 있는 것으로 보여진다. 48시간동안 두께 변화는 최대 20m이다. 72시간 동안 관측된 냉수의 평균 남하 속도는 17 cm/sec이다 냉수의 남하와, 냉수층 상부의 반류를 이해하기 위하여 역학모델을 적용하였다 모델로 구한 남향류의 최대 유속은 약 7 cm/sec이며, 수직와도점성계수는 0.038 $m^2$/sec이다. 모델을 이용하여 구한 남하 수송량은 골의 북부에서 0.032$\times$$10^{6}$㎥/sec이다. 냉수의 위 부분에 반류가 존재하므로 남쪽으로 갈수록 남하하는 냉수의 양이 줄어든다. 남하하는 수송량은 상층의 수송량이 많을수록 증가하나, 상층의 밀도와 두 층 사이 경계면 기울기의 변화에는 영향을 받지 않는다

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양방향 LSTM 순환신경망 기반 주가예측모델 (Stock Prediction Model based on Bidirectional LSTM Recurrent Neural Network)

  • 주일택;최승호
    • 한국정보전자통신기술학회논문지
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    • 제11권2호
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    • pp.204-208
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    • 2018
  • 본 논문에서는 시계열 데이터인 주가의 변동 패턴을 학습하고, 주가 가격을 예측하기 적합한 주가 예측 딥러닝 모델을 제시하고 평가하였다. 일반신경망에 시계열 개념이 추가되어 은닉계층에 이전 정보를 기억시킬 수 있는 순환신경망이 시계열 데이터인 주가 예측 모델로 적합하다. 순환신경망에서 나타나는 기울기 소멸문제를 해결하며, 장기의존성을 유지하기 위하여, 순환신경망의 내부에 작은 메모리를 가진 LSTM을 사용한다. 또한, 순환신경망의 시계열 데이터의 직전 패턴 기반으로만 학습하는 경향을 보이는 한계를 해결하기 위하여, 데이터의 흐름의 역방향에 은닉계층이 추가되는 양방향 LSTM 순환신경망을 이용하여 주가예측 모델을 구현하였다. 실험에서는 제시된 주가 예측 모델에 텐서플로우를 이용하여 주가와 거래량을 입력 값으로 학습을 하였다. 주가예측의 성능을 평가하기 위해서, 실제 주가와 예측된 주가 간의 평균 제곱근 오차를 구하였다. 실험결과로는 단방향 LSTM 순환신경망보다, 양방향 LSTM 순환신경망을 이용한 주가예측 모델이 더 작은 오차가 발생하여 주가 예측 정확성이 향상되었다.

북동태평양 원양성 적점토의 지질공학적 특성에 관한 연구 (Geotechnical Properties of Pelagic Red Clay in Northeast Equatorial Pacific)

  • 지상범;이현복;형기성;주세종;이근창;함동진
    • 한국해양학회지:바다
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    • 제13권3호
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    • pp.286-294
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    • 2008
  • 북동태평양 클라리온-클리퍼톤 균열대(Clarion-Clipperton Fracture Zone, C-C지역) 사이의 북쪽지역에 위치한 연구지역 원양성 적점토 표층퇴적물의 특성파악을 위해 기계적 교란이 적은 다중주상시료채취기로 24개 정점에서 시료를 채취하였다. 채집된 퇴적물 시료의 입도, 함수율, 밀도, 공극률 등 지표 특성과 전단강도, 컨시스턴시 한계 등의 지질공학적 특성 그리고 생물기원 오팔함량 및 광물조성을 분석하였다. 원양성 적점토가 분포하는 광범위한 연구지역($15^{\circ}45'{\sim}16^{\circ}55'N,\;125^{\circ}20'{\sim}134^{\circ}10'W$) 퇴적물의 지표 특성 및 광물학적 특성은 동일 경도 상에서 동측지역과 서측지역 사이의 큰 거리차이에도 불구하고 매우 균일한 특성을 보인다. 단지 표층퇴적물의 전단강도는 KR1 지역에 비해 KR2지역이 고화된 특성을 보이는데, 이것은 KR2 지역에서 나타나는 하부 Unit 3의 영향에 의한 것으로 판단된다.

한반도 상공의 오존층 변화 1985~2009 (The Variations of Stratospheric Ozone over the Korean Peninsula 1985~2009)

  • 박상서;김준;조나영;이윤곤;조희구
    • 대기
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    • 제21권4호
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    • pp.349-359
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    • 2011
  • The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

동해남부해역과 울릉분지의 퇴적상과 퇴적작용 (Sedimentary Facies and Processes in the Ulleung Basin and Southern East Sea)

  • 이병관;김석윤
    • 한국수산과학회지
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    • 제40권3호
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    • pp.160-166
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    • 2007
  • The coarse deposit with a lower mud content adjacent to the shelf of the southern East Sea is probably a "relict" sediment deposited in response to a lower stand of sea level during the Pleistocene. The sediment that developed on the slope and in the deep sea was river-borne primarily and was secondarily reworked or redistributed by the Tsushima Warm Current from the East China Sea. The clay mineralogy of the area suggests various sources of fine-grained sediment from adjacent rivers, the Korea Strait, volcanic material from Ulleung Island, and the Japan coast. Massive sand, bioturbated mud, homogeneous mud, and laminated mud were the dominant facies found in the core sediments from the study area. The massive sand was mainly volcanic ash from an eruption on Ulleung Island (9300 yr BP) and consisted of colorless pumiceous glass and a black scoriaceous type. The sedimentation rates on the slope, based on the Ulleung-Oki ash layer, were about 10cm/ky higher than in the basin. Other than the coarse-grain sediment, the mean size of the fine sediment dominating the bioturbated and homogeneous muds in the basin and the laminated mud on the slope was 6-10 phi. This indicates a difference in the major sedimentary process: hemipelagic sedimentation in the Ulleung Basin and mass flow deposition, such as turbidite, on the slope of the southern East Sea.

A dual padding method for ischial pressure sore reconstruction with an inferior gluteal artery perforator fasciocutaneous flap and a split inferior gluteus maximus muscle flap

  • Ku, Inhoe;Lee, Gordon K.;Yoon, Saehoon;Jeong, Euicheol
    • Archives of Plastic Surgery
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    • 제46권5호
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    • pp.455-461
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    • 2019
  • Background Various surgical management methods have been proposed for ischial sore reconstruction, yet it has the highest recurrence rate of all pressure ulcer types. A novel approach combining the advantages of a perforator-based fasciocutaneous flap and a muscle flap is expected to resolve the disadvantages of previously introduced surgical methods. Methods Fifteen patients with ischial pressure ulcers with chronic osteomyelitis or bursitis, who underwent reconstructive procedures with an inferior gluteal artery perforator (IGAP) fasciocutaneous flap and a split inferior gluteus maximus muscle flap from January 2011 to June 2016, were analyzed retrospectively. The split muscle flap was rotated to obliterate the deep ischial defect, managing the osteomyelitis or bursitis, and the IGAP fasciocutaneous flap was rotated or advanced to cover the superficial layer. The patients' age, sex, presence of bursitis or osteomyelitis, surgical details, complications, follow-up period, and ischial sore recurrence were reviewed. Results All ischial pressure ulcers were successfully reconstructed without any flap loss. The mean duration of follow-up was 12.9 months (range, 3-35 months). Of 15 patients, one had a recurrent ulcer 10 months postoperatively, which was repaired by re-advancing the previously elevated fasciocutaneous flap. Conclusions The dual-flap procedure with an IGAP fasciocutaneous flap and split inferior gluteus maximus muscle flap for ischial pressure ulcer reconstruction is a useful method that combines the useful characteristics of perforator and muscle flaps, providing thick dual padding with sufficient vascularization while minimizing donor morbidity and vascular pedicle injury.

전지구 해양 재분석 자료 비교 분석 (Intercomparison of the Global Ocean Reanalysis Data)

  • 장유순
    • 한국해양학회지:바다
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    • 제20권2호
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    • pp.102-118
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    • 2015
  • 본 연구에서는 국제 공동 해양 재분석 자료 비교 프로젝트 결과를 요약하였다. 다양한 재분석 자료 생산 시스템의 종류 및 특성을 소개하였으며, 대표적인 8가지 해양 변수(열용량, 열염분 높이, 해수면 높이, 표층 열속, 혼합층 깊이, 아표층염분, $20^{\circ}C$ 등온선 깊이, 해빙)에 대한 전지구 해양 자료 동화 모델 성능을 비교 분석하였다. 일반적으로 단일 재분석 자료 결과보다 앙상블 평균 값이 비교적 높은 성능을 나타내었으나, 검증 변수와 해역에 따라 서로 다른 특징을 보였다. 해양 변수 중에는 염분 및 해빙 변동이 모델간 가장 큰 편차를 보였다. 심층 해역, 남극해, 서안 경계 해역을 포함한 연안역에서는 공통적으로 객관 분석장과 동화 모델간의 편차가 크게 나타났다. 국내에서도 독립적으로 운영되고 있는 해양 자료 동화 모델간의 비교 분석 프로그램이 추진되어, 향후 관련된 국제 공동 연구에 활발히 참여할 수 있는 기회가 확대되기를 기대한다.