• 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.

• 감성과학
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• 제5권3호
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• pp.1-10
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• 2002

This paper concerns with the relationship between the visual perception of the degree of pucker or wrinkles of garment surfaces and the geometrical parameters of surfaces. In this study, four potentially relevant parameters of the surface profile are considered, namely, the variance ($\sigma$$^2$), the cutting frequency (F$\_$c/), the effective disparity curvature (D$\_$ce/) (Defined as the average disparity curvature of the wrinkled surface over the eyeball distance of the observer) and the frequency component of the disparity curvature ( D$\_$cf/). Based on the experiments using garment seams having varying degree of pucker (i.e. the wrinkles along a seam line), it was found that, while the logarithm of each of these four parameters has a strong linear relationship with the visually perceived degree of wrinkles, following the Web-Fetchner Law, the effective disparity curvature ( D$\_$ce/) and the frequency component of the disparity curvature (D$\_$cf/) appeared to have stronger relationships with the visual perception. This finding is in agreement with the suggestion by Rogers '||'&'||' Cagenello that human visual system may compute the disparity curvature in discriminating curved surfaces. It also suggested an objective method of measuring the degree of surface wrinkles.

• 패션비즈니스
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• 제23권1호
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• pp.116-126
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• 2019

The purpose of this study is to objectify the shape of curvature and average change rate of angular and arched eyebrow makeup. The data for the analysis were the final 336 pieces for the cosmetology students in the whole country. SPSS 20.0 program was used for the collected data, frequency analysis, factor analysis, reliability analysis, and crossover analysis were performed. First, the frequency of the average change rate of eyebrow makeup (angular and arcuate) was analyzed. As a result, the eyebrows suitable for the angled type showed the highest level of 'A-2' and the arched eyebrows had the highest level of 'B-2'. Second, to analyze the important factors of eyebrow makeup, frequency of eyebrows was the most important, followed by the inclination of eyebrows and eyebrow tail. Third, factor analysis and reliability analysis were conducted to examine each dimension of eyebrow makeup perception, and it was derived from three factors including acceptability, aggressiveness, and playability. Fourth, in order to analyze the difference of important factors in the form of the standard eyebrow makeup, the cross - analysis was performed with chi - square test, and it was confirmed that the angular eyebrow makeup showed the most objectivity when the average change rate was 0.29 and the curvature was 0.67. Fifth, arcuate eyebrow makeup showed the most objectivity when the average change rate was 0.57 and curvature was 0.56. The results of this analysis can be used as objective data of aesthetic criteria when designing the eyebrow shape.

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.197-206
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• 1996

This study ws performed to investigate the relationship between cervical curvature and the spatial position of the posterior part of the atlas imaged in the lateral cephalograph. Sixty six patients with temporomandibular disorders(TMD) and twenty dental students were selected for patients group and control group, respectively. The average age of patients group was 26.3 years, and 24.9 years in control group. Measured variables were cervical depth, upper space between the atlas and the base of the occiput, lower space between the atlas and the spinous process of the axis, rea of the posterior part of the atlas imaged in the lateral cephalograph, and the cervical curvature passing through the uppermost point in dorsal side of Dens of the Axis to the lowermost and rearmost point of the 5th cervical vertebra. The reliability of the method used for measuring cervical curvature with curved ruler was also tested. The results obtained were as follows : 1. Cervical depth of patients group was 122.9mm and significantly shorter than that of control group, in which cervical depth was 131.9mm, and cervical depth was significantly correlated with other variables in all subjects. 2. Upper space was greater in patients group, but total space including upper and lower space showed no difference between the two groups. The average value of total space was 26.5mm. 3. Area of the posterior part of the atlas was 168.2$\textrm{mm}^2$ in patients group, and 186.5$\textrm{mm}^2$ in control group with significant difference between the two groups. 4. Average range of radius of cervical curvature were 33-40cm and there was no difference between the two groups. 5. There was no significant correlation between the cervical curvature and the area of the posterior arch of the atlas. 6. The method using curved ruler for measuring cervical curvature could be accepted as a reliable method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.295-298
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• 2000

In this research, a novel sampling strategy for a CMM to inspect freeform surfaces is proposed. Unlike primitive surfaces, it is not easy to determine the number of sampling points and their locations for inspecting freeform surfaces. Since a CMM operates with slower speed in measurement than optical measuring devices, it is important to optimize the number and the locations of sampling points in the inspection process. When a complete inspection of a surface is required, it becomes more critical. Among various factors to cause shape errors of a final product, curvature characteristic is essential due to its effect such as stair-step errors in rapid prototyping and interpolation errors in NC tool paths generation. Shape errors are defined in terms of the average and standard deviation of differences between an original model and a produced part. Proposed algorithms determine the locations of sampling points by analyzing curvature distribution of a given surface. Based on the curvature distribution, a surface area is divided into several sub-areas. In each sub-area, sampling points are located as further as possible. The optimal number of sub-areas. In each sub-area, sampling points are located as further as possible. The optimal number os sub-areas is determined by estimating the average of curvatures. Finally, the proposed method is applied to several surfaces that have shape errors for verification.

• Interaction and multiscale mechanics
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• 제1권1호
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• pp.123-142
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• 2008

Current methodologies used for the inference of thin film stresses through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. These methodologies have recently been extended to non-uniform stress and curvature states for the thin film subject to non-uniform, isotropic misfit strains. In this paper we study the same thin film/substrate system but subject to non-uniform, anisotropic misfit strains. The film stresses and system curvatures are both obtained in terms of the non-uniform, anisotropic misfit strains. For arbitrarily non-uniform, anisotropic misfit strains, it is shown that a direct relation between film stresses and system curvatures cannot be established. However, such a relation exists for uniform or linear anisotropic misfit strains, or for the average film stresses and average system curvatures when the anisotropic misfit strains are arbitrarily non-uniform.

• 한국음향학회지
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• 제43권2호
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• pp.168-177
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• 2024

수중 압전 에너지 하베스터(Piezoelectric Energy Harvester, PEH) 설계시 곡률변화를 통해 외팔보형 전체의 와류유기진동(Vortex Induced Vibration, VIV)을 생성시키고, VIV의 생성으로 곡면형 외팔보 PEH에 진동 변위가 증가한다는 것은 실제 전력을 증대 시키는 데 중요한 요소이다. 해석 모델인 곡면형 PEH의 재질은 Polyvinyline Di-Floride(PVDF) 압전 필름으로서 곡률이 다양한 50 mm, 130 mm, 210 mm 모델에 유속은 0.1 m/s ~ 0.50 m/s로 정하여 VIV에 의한 PEH의 스트레인 에너지 변화를 관찰하였다. 곡률 반경이 작을수록 큰 폭의 VIV가 나타났고, 유속이 증가할수록 VIV가 많이 나타났다. 작은 곡률로 인한 급격한 형상변환이 VIV의 생성에 효과적이었고 스트레인 에너지, 정규화 발생 전압, 평균 전력 등은 곡률이 증가할수록 감소하였다. PEH 자체의 전력량을 증대시키기 위해 급한경사의 곡률 개선뿐만 아니라 곡률형 PEH의 개수가 늘어남에 따라 평균 전력도 상승할 것으로 사료된다.

• 한국방사선학회논문지
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• 제11권6호
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• pp.467-473
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• 2017

의료용 디지털 영상 및 통신 표준과 3차원 의료 영상 프로그램을 이용하여 외이도의 해부학적 특징들을 비교하였다. 실험은 연령과 성별이 다른 63귀의 영상을 이용하여 외이도의 횡축 길이, 내부 직경 둘레, 상하부 굴곡 각도를 측정한 후 비교하였다. 실험 결과 외이도 형태는 연령과 성별 뿐 만 아니라 동일인의 좌.우 에서도 다르게 나타났다. 성별 비교에서 남자 35귀, 여자 28귀에 대한 평균 길이는 남자가 4.75mm 길게 나타났다. 외이도 직경 둘레는 하부 굴곡 각도를 중심으로 내측이 외측 보다 평균 37.2% 감소된 형태로 나타났다. 상하부 굴곡 각도는 상부가 평균적으로 $25.7^{\circ}$ 높았으나 4귀에서 하부 각도가 높고, 연령이 낮은(4~14세) 8귀에서 상하부 굴곡 각도 차이가 크게 나타났다. 이는 성장하면서 외이도 굴곡 모양이 변화됨을 나타냈다. 본 연구는 기존 귀본 채취를 통한 간접 측정과 물리적 방법에 의한 직접 측정과 비교하여 안전성과 정밀성을 높일 수 있는 방법이다. 이는 3차원 의료 영상 표현 기술이 실제에 가깝게 표현할 수 있는 기술 향상 때문이며 더 발전하여 외이도 형태의 표준화 연구에도 활용될 수 있는 측정 방법이라 판단된다.

• 한국의류학회지
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• 제33권3호
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• pp.401-409
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• 2009

The shape of crotch area is very important to develop functional clothing as well as other ergonomic goods such as chair or saddle etc. However, it is inevitable that 3D scanned image of crotch would have missing part due to its folded shape including overlapping legs nearby. Therefore, the objectives of this research was to compare reconstruction methods of missing parts at crotch using seven dummies of real men's replicas. Two reconstruction methods adopted were kinds of 'fill- hole' in Rapidform 2004, one was 'smooth' and the other was 'curvature'. Each restored image was compared with the original shape of the dummies. As results, the average distance was 0.66mm between original and 'smooth' treated images and 0.59mm between original and 'curvature' treated, which was not statistically different. Average area of restored crotch region was $8740.04cm^2$ by 'smooth' method and $8405.02cm^2$ by 'curvature' method which is close to the original area of $8413.76cm^2$. Statistical difference was found between images of original and 'smooth' ones$(p=0.04^*)$. However, there was no difference between original and 'curvature' treated images, which indicates that 'curvature' method is more useful to fill the hole compared with 'smooth' method.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.17-20
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• 2005

Moment-curvature relation of RC pier is influenced greatly in occurrence form of crack and difference is happened according to consideration existence and nonexistence of tension stiffening effect. However, studies considering these is very insufficient misgovernment. Also, it is sometimes unavoidable lap splice of axial reinforcement in plastic hinge region of RC piers. However, specific design standard about lap splice of axial reinforcement is unprepared real condition and study about effect that lap splice of axial reinforcement get in occurrence form of crack is insufficient misgovernment. Therefore, in this paper, experiments are performed with hollow RC piers that do lap splice of axial reinforcement by main variable. And this study present analytical method about moment-curvature relation of hollow RC pier that consider tension stiffening effect and analyze effect that lap splice of axial reinforcement gets in occurrence form of crack. Analytic method of moment-curvature relation of RC pier that present in this study shows very similar motion with experiment result and crack interval of RC pier is suffering dominate impact in the augmented reinforcement amount by lap splice and average crack interval decreases as lap splice ratio increases.