• 열처리공학회지
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• 제16권4호
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• pp.211-215
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• 2003

In this work, a new way of measuring the volume fraction of e martensite in Fe-based alloys has been proposed. Since the specific volume of ${\varepsilon}$ martensite, depending on alloy composition, is smaller than that of austenite i.e ${\gamma}$ phase, volume expansion takes place during ${\varepsilon}{\rightarrow}{\gamma}$ reverse transformation. As the amount of the volume expansion is proportional to the product of specific volume difference times the volume fraction of ${\varepsilon}$ martensite, the volume fraction of ${\varepsilon}$ martensite can be calculated by measuring the volume expansion and the specific volume difference. Such a relationship was confirmed in Fe-21Mn and Fe-32Mn-6Si alloys which undergo ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation on cooling and by cold rolling, respectively. It was also found that the former has isotropic ${\varepsilon}$ martensite while the latter has anisotropic ${\varepsilon}$ martensite.

• 디지털융복합연구
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• 제12권10호
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• pp.425-431
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• 2014

본 연구는 ATOM Phantom을 이용하여 선량, 화질을 비교 분석 하여 Volume mode의 유용성 밝혀 소아 CT 검사에 적극적으로 사용하기 위함이다. Helical mode Noise와 Volume mode의 Noise, HU, SNR은 p>0.05 이므로 통계적으로 유이한 차이가 없음을 알 수 있었다. 각 부위별 선량값은 모두 p>0.05 이므로 통계적 유이한 차이가 없었으나 DLP값이 Helical mode보다 Volume mode가 더 낮게 측정되었다. 유효선량 역시 Volume mode가 Helical mode 보다 낮음을 알 수 있었다. 정성적 분석에서는 Mode에 따른 조건 별로 각각 Helical: 2.6, 3.3, 4.36 Volume: 2.8, 3.64, 4.44, Mode별 Follow up 영상평가 결과로는 Helical mode가 3.8 Volume mode가 3.83점으로 큰 차이가 없는 것으로 나타났다. 5세 이하의 소아 CT검사에 있어서 640-MDCT Volume scan이 Helical mode와 비교해 낮은 선량으로 영상의 질이 큰 차이가 없기에 소아 CT 검사에는 유용 하다고 생각된다.

• 대한치과보철학회지
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• 제49권2호
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• pp.152-160
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• 2011

연구 목적: 상악 중절치에 여러 가지 수복물 설계와 변연부 위치를 설정하여 치아 삭제를 하였을 때 나타나는 치아 삭제량의 변화를 평가하기 위함이다. 연구 재료 및 방법: 36개의 상악 중절치 레진 인공치가 실험에 사용되었다. 수복물의 디자인에 따라 이들은 4개의 군으로 나뉘었다. 그리고 각각의 군은 다시 변연부의 위치에 따라 3개의 세부 군으로 나뉘었다. 삭제되지 않은 치아의 부피가 미세단층촬영을 이용해 측정되었고 같은 방법으로 삭제 후의 치아의 부피가 측정되었다. 이 측정된 영상들을 서로 겹쳐서 비교함으로 삭제 전과 후의 부피 변화를 알아보았다. 결과: 수복물 설계에 따른 삭제 전과 후의 부피 변화량은 다음과 같은 순서로 변화량의 차이를 보였다: traditional laminate veneer < full laminate veneer < all ceramic crown < metal ceramic crown. One-Way ANOVA와 다중비교 Tukey로 유의수준5%에서 통계 분석한 결과 각각의 군에서는 다음과 같은 순서로 변화량의 차이를 보였다: CEJ 1 mm 상방 < CEJ < CEJ 1 mm 하방 (P<.05). 부피 변화를 백분율로 나타낸 수치를 보면 all ceramic crown과 metal ceramic crown 에서는 31 - 48% 로 나타났고 laminate veneer에서는 14 - 30%로나타났다. Laminate veneer에서 나타난 부피 변화량은 metal ceramic crown의 1/3로 나타났다. The full laminate (CEJ 1 mm 하방)와 all ceramic crown (CEJ 1 mm 상방)는 유사한 부피 변화를 보였다. Metal ceramic crown은 all ceramic crown과 비교하였을 때 13.7% 더 많은 부피 변화를 보였다. 결론: 수복물의 설계와 변연부 위치의 변화에 따라 부피 변화의 차이가 존재한다.

• Journal of the Korean Data and Information Science Society
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• 제25권1호
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• pp.237-244
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• 2014

It is known that the dierence in the length between two location parameters of two random variables is equivalent to the difference in the area between two cumulative distribution functions. In this paper, we suggest two applications by using the difference of distribution functions. The first is that the difference of expectations of a certain function of two continuous random variables such as the differences of two kth moments and two moment generating functions could be defined by using the difference between two univariate distribution functions. The other is that the difference in the volume between two empirical bivariate distribution functions is derived. If their covariance is estimated to be zero, the difference in the volume between two empirical bivariate distribution functions could be defined as the difference in two certain areas.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.49-57
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• 2020

We have not identified on what gender difference during gait at a pace of one's preferred velocity effects on the function of bilateral lower limb. This study was undertaken to investigate a difference of gait strategy by gender during gait at a one's preferred velocity of participants of adult male and female (n=20). Cinematographic data for motion analysis, ground reaction force (GRF) variables, and muscle volume of lower limb were analyzed. Significant difference of variables on movement of center of mass whole body, joint angle and moment of lower limb, and ground reaction force were tested by 2-way ANOVA analysis (P<0.05). Male group showed more muscle volume than female, and both showed more volume in dominant leg than non-dominant. Main effect by bilateral leg during gait showed higher difference in right than left leg in change of vertical position of center of mass (maximal, minimal). Main effect by gender in vertical change of position and velocity of center of mass showed higher difference in male than female (maximal, minimal). Hip joint showed more flexed and extended angle in male than female, and also dorsiflexion of ankle and flexion moment of knee and hip joint showed higher in male than female group. Therefore, this result was assumed that dominant showed furthermore more contribution for propulsive function than non-dominant leg. Gender difference showed in strategy controlling of biomechanical characteristics, and perhaps influenced by muscle volume.

• Journal of the korean society of oceanography
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• 제39권3호
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• pp.155-162
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• 2004

The variation of volume transport during the period from 1965 to 2000 through the western channel of the Korea Strait was estimated by obtaining an relation function between the ADCP volume transport and the geostrophic volume transport estimated by the sea level difference between Pusan and Izuhara. The estimated climatological mean volume transport during past 36 years has seasonal variation with a minimum of 1.15 Sv in February and a maximum of 1.88 Sv in October. The mean volume transport for 36 years is 1.51 Sv. The annual mean volume transport has an interannual variation with a minimum of 1.26 Sv in 1968 and maximum of 1.90 Sv in 1973, with three dominant periods of variations of 14.96 years, 4.96 years and 2.99 years.

• 대한치과교정학회지
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• 제23권2호
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• pp.275-282
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• 1993

When mandibular prognathic patients are operated orthognathic surgery which reduce the oral cavity volume, tongue volume should be harmonized with oral cavity volume to be changed because prevent the relapse of malocclusion. To decide the need for tongue resection, the author measured the tongue volume and oral cavity volume with stone model which were taken by impression method and study the difference between the ratio of tongue and oral cavity volume in mandibular prognathic group and normal group. The samples were consisted of four groups, the 40 subjects of the control group, 40 subjects of the experimental group. Each group was subdivided into male and female group respectively. The results were as follows : 1. The tongue volume and oral cavity volume measurements are $20.7cm^3,\;32.7cm^3$ in the control group respectively, and $24.9cm^3,\;42.9cm^3$ in the experimental group respectively. 2. There is no difference in the ratio of the tongue volume to oral cavity volume in control group and experimental group. 3. Correlation coefficients between the tongue volume and oral cavity volume are 0.11, 0.29 in experimental group and control group respectively, and 0.43 in gross total group. 4. The tongue volume of male is larger than female(p<0.05).

• Korea-Australia Rheology Journal
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• 제17권4호
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• pp.149-156
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• 2005

A simple constitutive model for viscoelastic suspensions is discussed in this paper. The model can be used to predict the rheological properties (relative viscosity and all stresses) for viscoelastic suspensions in shear and elongational flow, and the constitutive equations combine a 'viscoelastic' behaviour component and a 'Newtonian' behaviour component. As expected, the model gives a prediction of positive first normal stress difference and negative second normal stress difference; the dimensionless first normal stress difference strongly depends on the shear rate and decreases with the volume fraction of solid phase, but the dimensionless second normal stress difference (in magnitude) is nearly independent of the shear rate and increases with the volume fraction. The relative viscosities and all the stresses have been tested against available experimental measurements.

• 한국산림과학회지
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• 제99권3호
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• pp.304-311
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• 2010

본 연구는 2006년부터 시작된 국가산림자원조사부터 표본점 설계방법과 적용 단목재적식을 변경하여 적용함으로써 과거와는 다른 임목축적 추정치의 경향을 보이고 있어 그 원인을 구명하기 위해 수행하였다. 이를 위해 본 연구에서는 20개 집락의 80개 표본점을 대상으로 제4차 및 제5차 국가산림자원조사의 표본점 설계방법에 따라 자료를 수집한 후, 현재 사용하고 있는 수종별 단목재적식과 과거에 사용하였던 단목재적식을 적용하여 임목축적을 추정한 후 표본점 설계 방법 및 적용 단목재적식의 변경에 따른 임목축적 추정치의 차이가 있는지를 평가하였다. 임목축적 차이의 원인을 구명하기 위해 t-검정을 실시한 결과 표본점 설계방법의 변경에 따른 임목축적의 차이는 인정되지 않았으며, 사용된 단목재적식의 변경에 의해서 통계적으로 인정할 수 있는 임목축적의 차이가 발생하는 것으로 분석되었다. 결과적으로 제5차 국가산림자원조사를 통해 얻어지는 임목축적은 적용 단목재적식의 변경에 의해 차이가 발생하기 때문에, 국제기구에 보고하기 위해서는 재계산을 통해 2006년 이전의 임목축적 추정치의 보정이 필요할 것으로 평가되었다.

• 대한방사선기술학회지:방사선기술과학
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• 제46권6호
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• pp.527-533
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• 2023

The purpose of this study is to evaluate the clinical risk of spinal radiosurgery by calculating the dose difference due to dose calculation algorithm and multi-leaf collimator positioning error. The images acquired by the CT simulator were recalculated by correcting the multi-leaf collimator position in the dose verification program created using MATLAB and applying stoichiometric calibration and Monte Carlo algorithm. With multi-leaf collimator positioning error, the clinical target volume (CTV) showed a dose difference of up to 13% in the dose delivered to the 95% volume, while the gross tumor volume (GTV) showed a dose difference of 9%. The average dose delivered to the total volume showed dose variation from -8.9% to 9% and -10.1% to 10.2% for GTV and CTV, respectively. The maximum dose delivered to the total volume of the spinal cord showed a dose difference from -14.2% to 19.6%, and the dose delivered to the 0.35 ㎤ volume showed a dose difference from -15.5% to 19.4%. In future research, automating the linkage between treatment planning systems and dose verification programs would be useful for spinal radiosurgery.