• 한국간호교육학회지
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• 제12권2호
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• pp.214-223
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• 2006

Purpose: This study is to find the significant symptoms related to bone density, from which a cost-effective nursing diagnosis and intervention can be derived. Method: The research sample was 102 women, the sampling was designed by the researcher's convenience, and the subjects of the sample voluntarily participated in a questionnaire survey and measurements. The questionnaire asked socio-demographics, women' reproductive health symptoms, and the life style of the subject. Osteometer DTX-200 for bone density measure and a ruler for measuring spinal curvature were used. All the data were collected at the two public health clinics in a city in Korea. Result: The subjects' current and completed menopause ages, duration of menopause, degree of spinal curvature, BMI, frequency of parity and etc. showed significant correlations with bone density. However, only the degree of spinal curvature(p<.001, r=-.22) was found to be meaningful as a predicted factor for self diagnosis of bone density level. Conclusions: Since most of the subjects have not recognized the relationships between changes in spinal curvature and lowered bone densities, nurse needs to educate clients to get medical assistance to prevent from further bone density reduction by earlier finding of spinal curvature.

• 대한방사선기술학회지:방사선기술과학
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• 제30권4호
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• pp.335-341
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• 2007

Simple chest radiography에서 정상인의 가로막(diaphragm)에 대한 계측치는 다음과 같다. 1. 전체 대상자에 대한 흉곽(internal diameter of thorax: ID)의 평균은 293.3 mm이었으며, 최소 221.0 mm, 최대 335.3 mm이었다. 2. 가로막의 높이는 오른 가로막이 높은 경우가 81.4%, 오른 가로막과 왼 가로막이 동일한 경우가 16.2%, 왼 가로막이 높은 경우가 2.4% 순으로 나타났다. 3. 오른 가로막이 높은 경우 오른 가로막의 평균 높이는 15.2 mm이었으며, 가장 낮은 경우는 2.0 mm, 가장 높은 경우는 41.7 mm이었다. 4. 왼 가로막이 높은 경우 왼 가로막의 평균 높이는 11.5 mm이었으며, 가장 낮은 경우는 4.7 mm, 가장 높은 경우는 30.4 mm이었다. 5. 가로막의 만곡도에서 오른 가로막의 평균 만곡은 22.9 mm이었고, 가장 작은 경우는 10.4 mm, 가장 큰 경우는 37.3 mm이었다. 6. 왼 가로막의 평균 만곡은 22.4 mm이었고, 가장 작은 경우는 11.3 mm, 가장 큰 경우는 42.2 mm이었다. 7. ID와 오른 가로막과 왼 가로막 만곡에 대한 관계에서 ID는 오른 가로막 만곡(r= .427, p<.001)과 왼 가로막 만곡(r= .425, p<.001)에서 모두 통계적으로 유의미한 정적 상관관계를 보였다. 8. 오른 가로막 만곡과 왼 가로막 만곡의 관계는(r= .403, p<.001) 통계적으로 유의미한 정적 상관관계를 보였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.129-133
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• 2000

It is reasonable to use the stereo vision and image processing technique to digitize 3D coordinates of grid points and to evaluate surface strains on a sheet metal parts. However this method has its intrinsic problems such as the difficulty in enhancement of bad images inevitable error due to digital image resolution of camera and frame grabber unreliability of strains and thickness evaluated from coarse grid on the corner area with large curvature and the limitation of the area that can be measured at a time. Therefore it is still hard to measure strain distribution over the entire surface of a medium,- or large-sized stamped part at a time even by using an automated strain measurement system. In this study the curvature correction algorithm based on the grid refinement and the geometry assembling algorithm based on the global error minimization (GEM) scheme are suggested. Several applications are presented to show the reliability and efficiency of these algorithms.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1676-1683
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• 2001

An experimental study on condensation heat transfer characteristics of helically coiled spiral tubes was performed. The refrigerant is R-113. A refrigerant loop was established to measure the condensation heat transfer coefficients. Experiments were carried out uniform heat flux of 15 kw/m$^2$, refrigerant quality of 0.1∼0.9, curvature ratio of 0.016, 0.025 and 0.045. The curvature of a coil was defined as the ratio of the inside diameter of the tube to the diameter of the bending circle. To compare the condensation heat transfer coefficients of coiled spiral tubes, the previous results on coiled plain tubes and straight plain tubes were used. The results shows that the condensation heat transfer coefficients of coiled spiral tubes largely increase, as increasing Re and quality, compared to those of coiled plain tubes and straight plain tubes. As increasing degree of subcooling, however, the condensation heat transfer coefficients on coiled spiral tubes decrease. It is found that the heat transfer enhancement is more better than coiled plain tubes and straight plain tubes, as increasing curvature ratio.

• 한국정밀공학회지
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• 제1권3호
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• pp.71-84
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• 1984

This paper examined strain distribution and radius of curvature of the bulge by finite element method and investigated limit polar thickness strain to predict the formability of sheet metal as we substituted effective strain and the radius of curvature obtained by FEM into instability condition equation successively. In experiment, the radius of curvature and limit polar thickness strainwere obtained by Moire method. Also, a concent- ric set of photogrid circles was used to measure the strain of arbitrary point and mild steel was used as material. This results obtained are as follows: 1) The radius of curvature obtained by FEM is in good agreement with the Moire experimental value. 2) The polar thickness strain is getting larger as the inside is approached from the edge. This means that fracture occurred near the ploe. 3) The circumferential strains agree closely with the meridian strains and the polar thickness strain is about twice the circumferential (or meridian) strain. This result agrees with the fact that anisotropy coefficient (R-value) obtained by tensile test is about one. 4) The theoretical results of limit polar thickness strain obtained by authors' method are better agreement with experimental results than other theoretical results. Therefore, we can better predict the formability of sheet metal with authors' method.

• 로봇학회논문지
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• 제18권1호
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• pp.18-28
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• 2023

This study introduces a smart wrist band system with pressure measurements using wrist skin curvature variation due to finger motion. It is easy to wear and take off without pre-adaptation or surgery to use. By analyzing the depth variation of wrist skin curvature during each finger motion, we elaborated the most suitable location of each Force Sensitive Resistor (FSR) to be attached in the wristband with anatomical consideration. A 3D depth camera was used to investigate distinctive wrist locations, responsible for the anatomically de-coupled thumb, index, and middle finger, where the variations of wrist skin curvature appear independently. Then sensors within the wristband were attached correspondingly to measure the pressure change of those points and eventually the finger motion. The smart wrist band was validated for its practicality through two demonstrative applications, i.e., one for a real-time control of prosthetic robot hands and the other for natural human-computer interfacing. And hopefully other futuristic human-related applications would be benefited from the proposed smart wrist band system.

• 유통과학연구
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• 제13권5호
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• pp.53-60
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• 2015

Purpose - The purpose of this paper is to shed light on the importance of the slope and curvature of the volatility curve implied in option prices in the KOSPI 200 options index. A number of studies examine the implied volatility curve, however, these usually focus on cross-sectional characteristics such as the volatility smile. Contrary to previous studies, we focus on time-series characteristics; we investigate correlation dynamics among slope, curvature, and level of the implied volatility curve to capture market information embodied therein. Our study may provide useful implications for investors to utilize current market expectations in managing portfolios dynamically and efficiently. Research design, data, and methodology - For our empirical purpose, we gathered daily KOSPI200 index option prices executed at 2:50 pm in the Korean Exchange distribution market during the period of January 2, 2004 and January 31, 2012. In order to measure slope and curvature of the volatility curve, we use approximated delta distance; the slope is defined as the difference of implied volatilities between 15 delta call options and 15 delta put options; the curvature is defined as the difference between out-of-the-money (OTM) options and at-the-money (ATM) options. We use generalized method of moments (GMM) and the seemingly unrelated regression (SUR) method to verify correlations among level, slope, and curvature of the implied volatility curve with statistical support. Results - We find that slope as well as curvature is positively correlated with volatility level, implying that put option prices increase in a downward market. Further, we find that curvature and slope are positively correlated; however, the relation is weakened at deep moneyness. The results lead us to examine whether slope decreases monotonically as the delta increases, and it is verified with statistical significance that the deeper the moneyness, the lower the slope. It enables us to infer that when volatility surges above a certain level due to any tail risk, investors would rather take long positions in OTM call options, expecting market recovery in the near future. Conclusions - Our results are the evidence of the investor's increasing hedging demand for put options when downside market risks are expected. Adding to this, the slope and curvature of the volatility curve may provide important information regarding the timing of market recovery from a nosedive. For financial product distributors, using the dynamic relation among the three key indicators of the implied volatility curve might be helpful in enhancing profit and gaining trust and loyalty. However, it should be noted that our implications are limited since we do not provide rigorous evidence for the predictability power of volatility curves. Meaning, we need to verify whether the slope and curvature of the volatility curve have statistical significance in predicting the market trough. As one of the verifications, for instance, the performance of trading strategy based on information of slope and curvature could be tested. We reserve this for the future research.

• 소성∙가공
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• 제20권4호
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• pp.316-323
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• 2011

The hot curvature-forming of large aluminum thick plate using a grid-typed hybrid die is a process for the production of a spherical LNG tank. Many variables such as the initial die surface quality, grid size, grid thickness, size of blank plate and cooling line design, control the success of the process. In addition, the plate used in this process is generally larger than $10{\times}10m$ in size. Thus, it is very difficult to predict the surface characteristics of the plate during forming and to measure the different parameters due to the high cost of the experiments. In order to optimize the process design for the grid-type die, the development of an analytical method to predict the surface characteristics of the final product in hot curvature-forming is needed. This paper described the development of the method and procedures for FE simulations of the hot curvature-forming process, including hot forming, air flow, cooling, and thermal deformation analyses. An experiment for a small scale model of the process was conducted to check the validity of the numerical method. The results showed that the curvature of the plate in the analysis agrees well with that of the experiment within 0.037 and 0.016% tolerance margins for its side and corner, respectively.

• 충청수학회지
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• 제34권4호
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• pp.397-409
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• 2021

The Bishop and Bishop-Gromov volume comparisons with the Bakry-Emery Ricci tensor in a metric measure space are studied by the comparisons of the Jacobi differential equations in a Riemannian and Lorentzian manifold.

• 한방재활의학과학회지
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• 제25권4호
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• pp.83-92
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• 2015

Objectives To measure and analyze the curvature of the cervical spine for university students. Methods This study carried out on 132 students. The cervical spine curvature was measured by six measuring methods. The type and numeric value of cervical spine curvature was analyzed by Angle of cervical curve (C1~C7), Angle of cervical curve (C2~C7), Jackson's angle, Ishihara Index, Depth of cervical curve and Method of Jochumsen. Cervical spine curvatures between male and female are compared by Mann-Whitney test. Rate of type of cervical curvature between male and female are compared by linear by linear association. Results 1. The average of angle of cervical curve (C1~C7) is $33.78{\pm}9.85^{\circ}$, angle of cervical curve (C2~C7) is $10.28{\pm}8.12^{\circ}$. The average of Jackson's angle is $14.02{\pm}10.01^{\circ}$, average of Ishihara Index is $8.46{\pm}10.58%$. The average of Depth of cervical curve is $5.15{\pm}4.72mm$ and average of Method of Jochumsen is $0.94{\pm}3.83mm$. 2. More than half of student's cervical curvature showed hypolordosis except Ishihara index. 3. There was significant difference in numeric value of cervical curvature between male and female both groups in terms of Ishihara index. 4. There were insignificant differences between male and female in terms of type of cervical curvature. Conclusions According to above results, we found out average of student's cervical curve. And the results suggest that most of the student's cervical curvature decrease.