• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.169-174
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• 2003

Design of a rational earth volume conversion coefficient is required as the earth volume conversion coefficient may give great influence on construction work volume and construction costs in the civil engineering works where large-scaled earth volume is excavated. However, there are a great deal of difficulties in the calculation of the exact spoil surface earth and Insufficient earth volume by adopting the figures presented on the generally used design specifications which are not the results obtained from the selection tests in calculating the earth volume conversion coefficient. In this connection, it would be desirable to calculate the earth volume conversion coefficient by carrying out large-scaled site test adequate for the relevant environment. In consequence, this study aims at calculating the exact earth volume conversion coefficient of cutting and banking areas of weathering rocks in large-scaled construction sites where land is being developed into home lots. For this, we have excavated the respective 20 sites of the cutting and banking areas in the said site and then calculated the volume after the excavation. As a result, the relative exactness degree of the crossing was calculated at 0.5% in average. The relative exactness degree of 0.5% in the volume may be judged as an exact measurement as it corresponds to 0.17% of the relative exactness degree in the length measurement. We have calculated the exact earth volume conversion coefficient by the use of function ratio as per the wet unit weight and the indoor soil quality test as per volume calculated. And then we have found out minor differences as a result of the comparison and analysis with the earth volume conversion coefficient determined by the dry unit weight test as per sand replacement method. This may be judged as a rational design method for the calculation of earth volume conversion coefficient, as well as high reliability of site test as a precision photogrammetry is adopted for volume measurement of the irregular excavating areas.

• Journal of Radiation Protection and Research
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• 제21권4호
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• pp.297-311
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• 1996

ANSI는 교정용 팬텀으로 PMMA 평판형 팬텀을 제시하면서 이에 대한 선량당량환산 계수를 계산하는 방법을 제시하였다. PMMA 평판형 팬텀에 대한 광자의 선량당량환산계수는 ICRU조직 정육면체 팬텀에 대한 후방산란인자 및 선량당량환산계수와 PMMA 평판에 대한 후 방산란인자를 각각 구한 후 이를 이용하여 간접적으로 계산하도록 제시하였다. 그러나 중성자에 대한 PMMA 평판형 팬텀에서의 선량당량환산계수의 계산방법은 아직도 제시하지 못하고 있다. 이 연구에서는 ANSI가 제시한 광자에 대한 선량당량환산계수 계산방법을 중성자에 대해 적용하여 PMMA 평판에 대한 중성자의 선량당량환산계수를 최초로 계산하였다. 중성자에 대해 선질가중조직커마를 도입하여 ICRU 정육번체와 PMMA 평판에서 후방산간인자를 계산하였고 ICRU 정육면체에 대한 중성자의 선량당량환산계수를 계산한 후 이를 이용하여 PMMA 평판에서의 중성자에 대한 선량당량환산계수를 계산하였다. 그 결과 PMMA 평판에 대한 중성자의 선량당량환산계수는 대부분의 에너지 영역에서 ICRU 정육면체에 대한 중성자의 선량당량환산계수와 10% 이내의 차이를 보였으나 1eV. 1keV, 4 MeV에서는 $15{\sim}20%$, 정도 크게 나타났다.

• Nuclear Engineering and Technology
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• 제42권1호
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• pp.89-96
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• 2010

This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ($^3H,\;^7Be,\;^{14}C,\;^{40}K,\;^{51}Cr,\;^{54}Mn,\;^{59}Fe,\;^{58}Co,\;^{60}Co,\;^{65}Zn,\;^{90}Sr,\;^{95}Nb,\;^{99}Tc,\;^{106}Ru,\;^{129}I,\;^{131}I,\;^{136}Cs,\;^{137}Cs,\;^{140}Ba,\;^{140}La,\;^{144}Ce,\;^{238}U,\;^{239}Pu,\;^{240}Pu$) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (${\mu}Gyd^{-1}$ per $Bqkg^{-1}$) ranged from $10^{-6}$ to $10^{-2}$ according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as $^{238}U,\;^{239}Pu$, and $^{240}Pu$, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of $^{239}U,\;^{240}Pu,\;^{238}U,\;^{14}C,\;^3H$, and $^{99}Tc$ were independent of the organism.

• Imaging Science in Dentistry
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• 제30권2호
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• pp.101-108
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• 2000

Purpose : The effects of step numbers of copper wedge and exposure on the coefficient of determination (r²) of the conversion equation to Cu-equivalent image and on the Cu-equivalent value (mmCu) and it's coefficient of variation measured at each copper step and the mandibular premolar area were evaluated. Method: Digital image analyzing system consisted of scanner, personal computer, and a stepwedge with 10 steps of 0.03 mm copper in thickness as reference material was prepared for quantitative assessment of the bone mineral density. NIH image program was used for analyzing images. Results : The film having moderately high film density showed the discrepancy between the real thickness and the measured Cu-equivalent value of each copper step. The Cu-equivalent image was dependent on the determinational coefficient of the conversion equation than the coefficient of variance of the measured value. Conclusion : Obtaining conversion equation with high coefficient of determination and proper film exposure are supposed to be neccessary for quantitative assessment of bone density. Multiple steps in the range of the corresponding copper thickness to the bone density of the area to be measured should be prepared.

• 한국운동역학회지
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• 제25권1호
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• pp.39-47
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• 2015

Objective : The purpose of this study was to investigate the velocity conversion coefficient and invariance for the optimal phase ratio on the performance of the women's triple jump. Methods : Three-dimensional kinematic data were obtained from the three finalists of the women's triple jumper competition at the 2011 Daegu IAAF World Championships. Computer simulations were performed using the biomechanical model of the triple jump to optimize the phase ratio for the longest actual distance for all athletes with altered velocity conversion coefficients. Results : Top elite triple jumpers showed better technical consistency at the phase ratio. Also, no consistent relationship was observed between the loss in horizontal velocity and the gain in vertical velocity across supporting the three phase. In addition, regardless of the magnitude A1, all athletes were optimized with jump-dominated technique. Finally, as the magnitude of A1 increased, the athletes showed better performance. The obtained overall distance jumped showed the longest actual distance when the optimal phase ratio was transferred from hop-dominated to jump-dominated(the step ratio was 30%~31%), and when the optimal phase ratio was transferred from balanced to jump-dominated(the step ratio was 27%~29%). Conclusion : Future studies need to be conducted in order to explore the active landing motion and the inclination angle of the body with the velocity conversion coefficient simultaneously at each supporting phase.

• Journal of electromagnetic engineering and science
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• 제8권2호
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• pp.84-89
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• 2008

In a wireless channel above microwave frequency, rain attenuation is very important. In order to predict rain attenuation, 1-min. rain rate distribution is required. This paper discusses appropriate conversion methods to estimate 1-minute rain rate from that of other integration time. Based on the measurement data filed in ITU-R WP3J including ETRI data for 6 consecutive years, distributions of rain rate with 1-, 5-, 10-, 20-, 30-minute integration time were analyzed, both on the global and regional basis, and the parametric relationship between the statistical characteristics of 1-minute and other measurement data were investigated to deduce the conversion methods. It is shown that the global model works good with good accuracy for 5-, 10-, 20-min integration time, and the global model is also applicable globally with good accuracy for 5-, 10-, 20-min integration time. The global conversion model was adopted last year as an ITU-R document for new recommendation. The regional conversion model would also be very useful for locations of similar climatic zone.

• 한국세라믹학회지
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• 제27권3호
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• pp.412-422
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• 1990

Porous SiC ceramics were proposed to be promising materials for high-temperature thermoelectric energy conversion. Throughthe thermoelectric property measurements and microstructure observations on the porous alpha SiC and the mixture of $\alpha$-and $\beta$-SiC, it was experimentally clarified that elimination of stacking faults and twin boundaries by grain growth is effective to increase the seebeck coefficient and increasing content of $\alpha$-SiC gives rise to lower electrical conductivity. Furthermore, the effects of additives on the thermoelectric properties of 6H-SiC ceramics were also studied. The electrical conductivity and the seebeck coefficient were measured at 35$0^{\circ}C$ to 105$0^{\circ}C$ in argon atmospehre. The thermoelectric conversion efficiency of $\alpha$-SiC ceramics was lower than that of $\beta$-SiC ceramics. The phase homogeneity would be needed to improve the seebeck coefficient and electrical conductivity decreased with increasing the content of $\alpha$-phase. In the case of B addition, XRD analysis showed that the phase transformation did not occur during sintering. On the other hand, AlN addiiton enhanced the reverse phase transformation from 6H-SiC to 4H-SiC, and this phenomenon had a great effect upon the electrical conductivity.

• 한국해양공학회지
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• 제19권6호통권67호
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• pp.1-7
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• 2005

This paper deals with the design and aerodynamic analysis of a special-type impulse turbine, with an end plate for wave energy conversion. Numerical analysis was performed using a CFD code, FLUENT. The main idea of the proposed end plate was to minimize the adverse effect of tip clearance of turbine blade, and was borrowed from ducted propeller, with so-called penetrating end plate for special purpose marine vehicles. Results show that efficiency increases up to $5\%$, depending on the flow coefficient; a higher flow coefficient yields increased efficiency. Decrease of input coefficient CAwith an end plate is the main reason for higher efficiency. Performance of end plate at various design parameters, as well as flow conditions, was investigated; the advantages and disadvantages of the presentimpulse turbine were also discussed.

• Journal of Radiation Protection and Research
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• 제26권2호
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• pp.73-78
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• 2001

3"X3" NaI 스펙트럼의 조사선량 변환계수를 구하기 위해, 조사선량률이 $4{\sim}23{\mu}R\;h^{-1}$인 29개 지역에서 가압전리함 검출기로 조사선량률을 측정하고, 동시에 3"X3"와 4"X4" NaI 검출기로 스펙트럼을 측정하였다. 총에너지 방법의 조사선량 변환계수는 측정된 조사선량률과 스펙트럼 에너지의 선형적 비례관계를 사용하여 구하였다. 에너지대 방법의 조사선량 변환계수를 구하기 위해 NCRP에서 권고하는 4"X4" NaI 검출기에 대한 에너지대 방법의 조사선량 변환계수를 4"X4" NaI 스펙트럼에 적용하여 $^{40}K,\;^{238}U,\;^{232}Th$ 계열의 조사선량률을 계산하였다. 이렇게 계산된 $^{232}Th$ 계열의 조사선량률과 $^{232}Th$ 계열을 대표하는 2614keV 피크 영역면적의 선형적 비례관계를 이용하여 3"X3" NaI 검출기 스펙트럼에 대한 $^{232}Th$ 계열 조사선량 변환계수를 구하였다. $^{40}K$ 및 $^{238}U$ 계열의 조사선량 변환계수도 유사한 방법으로 구해졌다.

• 한국방재학회 논문집
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• 제10권2호
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• pp.31-37
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• 2010

본 연구는 디지털 이미지 처리 기법을 이용하여 2차원 이미지를 3차원으로 변환하기 위하여 형상변환계수 및 등가직경이론을 제안하였고, 이를 이용하여 수정입도분포곡선을 작성하였다. 연구에 이용된 골재는 천연골재(해변자갈) 2종 및 쇄석골재 2종 등 총 4종의 골재를 이용하였다. 4종의 골재에 대한 편평비는 각각 0.30, 0.36, 0.47 및 0.83으로 측정되었다. 형상변환계수는 각각 0.77, 0.78, 0.84 및 0.92로 결정되었다. 형상변환계수에 디지털이미지 처리기법에서 구한 입경을 곱하여 입자의 크기를 보정하였다. 보정된 입자크기를 이용하여 보정된 체적 및 중량을 구하여 수정입도곡선을 작성하였다.