• 제목/요약/키워드: formula comparison

검색결과 528건 처리시간 0.026초

Comparison of Marine Insolation Estimating Methods in the Adriatic Sea

  • Byun, Do-Seong;Pinardi, Nadia
    • Ocean Science Journal
    • /
    • 제42권4호
    • /
    • pp.211-222
    • /
    • 2007
  • We compare insolation results calculated from two well-known empirical formulas (Socket and Beaudry's SB73 formula and the original Smithsonian (SMS) formula) and a radiative transfer model using input data predicted from meteorological weather-forecast models, and review the accuracy of each method. Comparison of annual mean daily irradiance values for clear-sky conditions between the two formulas shows that, relative to the SMS, the SB73 underestimates spring values by 9 W $m^{-2}$ in the northern Adriatic Sea, although overall there is a good agreement between the annual results calculated with the two formulas. We also elucidate the effect on SMS of changing the 'Sun-Earth distance factor (f)', a parameter which is commonly assumed to be constant in the oceanographic context. Results show that the mean daily solar radiation for clear-sky conditions in the northern Adriatic Sea can be reduced as much as 12 W $m^{-2}$ during summer due to a decrease in the f value. Lastly, surface irradiance values calculated from a simple radiative transfer model (GM02) for clear-sky conditions are compared to those from SB73 and SMS. Comparison with iu situ data in the northern Adriatic Sea shows that the GM02 estimate gives more realistic surface irradiance values than SMS, particularly during summer. Additionally, irradiance values calculated by GM02 using the buoy meteorological fields and ECMWF (The European Centre for Medium Range Weather Forecasts) meteorological data show the suitability of the ECMWF data usage. Through tests of GM02 sensitivity to key regional meteorological factors, we explore the main factors contributing significantly to a reduction in summertime solar irradiance in the Adriatic Sea.

목단피(牧丹皮)가 강제수영부하시험에서 Corticotropin-Releasing Factor, c-Fos 와 Tyrosine Hydroxylase에 미치는 영향 (Effects of Moutan Cortex on Corticotropin-Releasing Factor, c-Fos and Tyrosine Hydroxylase in Forced Swimming Test)

  • 성영석;이태희
    • 대한한의학방제학회지
    • /
    • 제17권1호
    • /
    • pp.129-140
    • /
    • 2009
  • Objectives : The goal of this study was to investigate the effect of Moutan Cortex as antidepressant in forced swimming test(FST) model. Methods : The expressions of corticotropin-releasing Factor(CRF), c-Fos and tyrosine hydroxylase(TH) were measured with immunohistochemical method at paraventricular nucleus (PVN), locus coeruleus(LC) and ventral tegmental area(VTA). Results : The duration of immobility in the forced swimming test was significantly decreased in the Moutan Cortex 100 mg/kg treated group in comparison with the control group(p<0.01). CRF and c-Fos expressions at PVN were decreased in the Moutan Cortex 100mg/kg treated group in comparison with the control group. But only the expression of c-Fos was shown the significance(p<0.05). TH expressions at LC and VTA were significantly decreased in the Moutan Cortex 100mg/kg and 400mg/kg treated group in comparison with the control group(p<0.001). Conclusion : According to the results, Moutan Cortex has the antidepressant effect by showing the reduced immobility through the reduction of c-Fos expression at PVN and the reduction of TH expression at LC and VTA.

  • PDF

수유방법별 관련요인 및 영아의 성장비교 (The study on related factors of feeding type and comparison of development between breast-fed and formula-fed infants)

  • 현혜진;권미경;한경자;윤순녕
    • 가정∙방문간호학회지
    • /
    • 제5권
    • /
    • pp.5-19
    • /
    • 1998
  • This study presents results of surveys conducted Seoul and Kangreung public health center using structured questionnaire developed by researchers to identify factors that were relevant to the method of feeding. To compare the infant's development between the breast-fed infants and formula-fed infants, infant's height, weight, triceps skinfold during 1month and 4months were cheked. The results were as follows : 1. At postpartum, 59.1% infants had formula feeding, while 22.6% had breast feeding. At 1 month old, 49.6% infants had formula feeding, 27.8% had breast feeding. At 4 months old, 60.9% infants had formula feeding, while 26.1% had breast feeding. 2. 'Lack of breast milk' was the predominant reason for formula feeding. 3. The sujects didn't enough eat not only rice and seaweed soup but also any other specific foods during breast feeding period. 4. Factors that affected the method of feeding were the patterns of delivery, mother's height & weight, first baby feeding type(at post partum), infant sex, mother's age, preparation of breast feeding, first baby feeding type, regular clinic visit (at 4months old). 5. The birth weight and height were correlated with mother's weight and height. 6. There were no significant different on infant's weight, height, triceps skinfold between breast-fed infants and formula-fed infants.

  • PDF

폭발해석을 위한 간략 폭발하중 제안식 (A Suggestion of Simplified Load Formula for Blast Analysis)

  • 전두진;한상을
    • 한국전산구조공학회논문집
    • /
    • 제29권1호
    • /
    • pp.67-75
    • /
    • 2016
  • 본 논문에서는 폭발해석에서 주로 사용되는 폭발하중의 압력-시간 이력곡선과 폭발하중 산정식인 Conwep 모델을 소개하고, 이를 더욱 간편하게 계산할 수 있는 간략 폭발하중 산정식을 제안한다. 폭발해석에서 폭발하중은 일반적으로 압력-시간 이력곡선의 형태로 적용되며, 그에 대한 주요 값들은 폭발하중 산정식에 의해 계산된다. 대부분의 폭발해석에서 사용되는 폭발하중 산정식인 Conwep 모델은 환산거리(scaled distance)를 핵심변수로 하여 계산되는데, 그 계산 과정이 매우 복잡한 단점이 있다. 따라서 본 논문에서는 환산거리를 변수로 갖는 간략한 유리식을 사용하여 주요 값들을 계산하고, 단순화된 압력-시간 이력곡선으로 폭발하중을 산정할 수 있도록 제안하였다. 간략식을 찾는 과정에서 Conwep 모델의 계산 결과를 바탕으로 곡선 적합(curve fitting) 방식이 사용되었으며, 제안된 간략식에 의한 주요 값의 계산 결과는 Conwep 모델과 비교하여 1% 미만의 오차를 갖는다. 또한, 유한요소를 이용한 폭발해석에 적용하였으며 Conwep 모델을 적용한 결과와 비교를 통해 검증하였다.

CCT 시험편을 이용한 저탄소강의 J 저항곡선에 관한 연구 (A Study on J-Resistance Curve of Low-Carbon Steel Using Center Cracked Tension Specimen)

  • 고성위
    • 수산해양기술연구
    • /
    • 제22권2호
    • /
    • pp.40-45
    • /
    • 1986
  • In this paper, the I-resistance curve of low-carbon steel with 3 mm thickness was investigated for various crack ratios. The experiments were carried out for the center cracked tension (CCT) specimen with about 50 mm width on an instron machine. The plane stress fracture toughness obtained by the Simpson's formula was Ii. = 24.96 kgffmm. Simpson's formula which considers crack growth in obtaining J integral showed more conservative lin than Rice's and Sumpter's. For materials that may be approximated by the Ramberg and Osgood stress strain law, the relevant crack parameters like the J integral, load line displacement are approximately normalized. Crack driving forces in terms of the I integral are computed for low-carbon steel CCT specimen using the above estimation scheme. Comparison of the prediction with actual experimental measurements by Simpson's formula showed good agreement for several different sized specimen.

  • PDF

회전날개 길이를 이용한 제로터 펌프/모터의 배제용적에 관한 연구 (An Analysis on Volumetric Displacement of Gerotor Pump/Motor Using Vane Length)

  • 김성동;김대명;함영복;한철호
    • 유공압시스템학회논문집
    • /
    • 제8권2호
    • /
    • pp.8-16
    • /
    • 2011
  • It is hard and complicated to analytically derive the volumetric-displacement formula of a gerotor pump/motor. Analytical formulas for calculating the volumetric-displacement are derived in this work, which is relatively easy and based upon vane lengths. The vane lengths mean the distances from axis of inner rotor or outer rotor to contact points between inner and outer rotors. Two kinds of formula were studied for two different kinematic motions of rotors. The first one is the case that outer rotor is fixed in space and inner rotor is in mixed motion of planetary revolution and rotation with respect to the spinning axis. And the second is the case that both inner and outer rotors simultaneously rotate. The proposed formula is verified through comparison with volumetric-displacement obtained from numerical CAD calculation.

전달함수합성법을 이용한 민감도 해석 (Sensitivity Analysis using FRF-based Substructuring Method)

  • 이두호;황우석;김찬묵
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2000년도 추계학술대회논문집A
    • /
    • pp.602-606
    • /
    • 2000
  • A general procedure for the design sensitivity analysis of structural dynamic problems has been presented in frame of the FRF-based substructuring formulation. In the procedure, the direct differentiation method is used for the sensitivity formula. For a system response function, the proposed method gives a parametric design sensitivity formula in terms of the partial derivatives of the connection element properties and the transfer matrix of the subsystems. The derived design sensitivity formula is applied to a numerical example. The comparison of sensitivities derived by the proposed method and the finite difference method shows that the proposed method is efficient and accurate.

  • PDF

데크플레이트의 웨브국부좌굴에 관한 내력식 제안 (A Proposal for Strength Formula of Web Crippling in Trapezoidal Sheeting)

  • 신태송
    • 한국강구조학회 논문집
    • /
    • 제13권6호
    • /
    • pp.641-649
    • /
    • 2001
  • 본 논문에서는 데크플레이트의 웨브 국부좌굴에 관한 실용적인 내력식을 제안하고자 한다. 실험에서 유추된 해석모델을 이론적으로 규명한 기존의 연구를 바탕으로 내력에 영향을 미치는 주요 변수들을 조사 분석하여 관련 함수들을 유도한다. 각 변수들을 기존의 실험자료와 종합적으로 비교 분석하여 간편한 내력식을 제안한다. 유럽기준 EC 3 부록 Z 에 따른 통계평가로부터 저항 부분안전계수 ${\gamma}_M$ 을 구하며 목표로 하는 값 1.1과 비교되어진다.

  • PDF

요마크 분석을 통한 사고 재구성 (Accident reconstruction using yaw mark analysis)

  • 하정섭;이승종
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2002년도 추계학술대회 논문집
    • /
    • pp.443-446
    • /
    • 2002
  • A vehicle oversteered or cornering at excessive speed leaves tire yaw mark on the road surface. A yaw mark is a sign that the tire was sideslipping and exceeded its frictional limit because of centrifugal force. Problems exist with the traditional equation, “critical speed formula (CSF)”, that limits its practical use in traffic accident reconstruction. A major problem is that the equation dose not account for vehicle dynamics and interface between tire and road. The literature refers to that the accuracy of the critical speed formula varies with several factors. New equations that account for vehicle dynamics are introduced in this paper. A comparison of the accuracy of the new method and the traditional method in the calculation of speed is conducted.

  • PDF

Shear strength formula of CFST column-beam pinned connections

  • Lee, Seong-Hui;Kim, Young-Ho;Choi, Sung-Mo
    • Steel and Composite Structures
    • /
    • 제13권5호
    • /
    • pp.409-421
    • /
    • 2012
  • Recently, as the height of building is getting higher, the applications of CFST column for high-rise buildings have been increased. In structural system of high-rise building, The RC core and exterior concrete-filled tubular (CFST) column-beam pinned connection is one of the structural systems that support lateral load. If this structural system is used, due to the minimal CFST column thickness compared to that of the CFST column width, the local moment occurred by the eccentric distance between the column flange surface from shear bolts joints degrades the shear strength of the CFST column-beam pinned connections. This study performed a finite element analysis to investigate the shear strength under eccentric moment of the CFST column-beam pinned connections. The column's width and thickness were used as variables for the analysis. To guarantee the reliability of the finite element analysis, an actual-size specimens were fabricated and tested. The yield line theory was used to formulate an shear strength formula for the CFT column-beam pinned connection. the shear strength formula was suggested through comparison on the results of FEM analysis, test and yield lime theory, the shear strength formula was suggested.