• 대한수학회보
• /
• 제47권3호
• /
• pp.503-511
• /
• 2010

We prove a common fixed point theorem for S-contraction mappings without continuity. Using this result we obtain an approximating curve for S-nonexpansive mappings in a Banach space and prove Browder's type strong convergence theorem for this approximating curve. The demiclosedness principle for S-nonexpansive mappings is also established.

• 한국안전학회지
• /
• 제27권2호
• /
• pp.117-126
• /
• 2012

Understanding driver's characteristic of visual activity is important process because driver depends on a visual signal more than 90% for getting outside information needed to drive, thus a series of driving, including perception, judgement, and activity, is completed. This study analyzes quantified driver's sight range in curved section where recognition of various information is critical due to biggest speed change among sections. Simulation is utilized for this study because of safety problem on field experiment and difficulties in using equipment. Building 6 roads that have different in curve radius by virtual driving map, experiment is carried out recruiting 30 people. Through analytical researches, it shows that drivers keep an eye on direction of driving, and driver's visual range is narrowed on left curve than right curve, and the more curve radius become small, the more drivers see in narrow angle.

• Journal of Astronomy and Space Sciences
• /
• 제17권2호
• /
• pp.181-188
• /
• 2000

DO Cas는 최근 Shaw (1990)에 의해 근접촉쌍성으로 분류된 공전주기 0.68일의 식쌍성이다. 짧은 공전주기를 가짐에도 불구하고 Mannino (1958) 이후 분광관측에 의한 시선속도 곡선이 발표되지 않고 있다. 그런데 Hill (1991)은 Mannino의 시선속도곡선이 오류를 포함하고 있는 것으 로 보인다고 하였다. 이 연구에서 우리는 Asiago 천문대에 의뢰하여 Mannino가 분석한 분광관측 사진건판을 입수하여 PDS로 측정하여 IRAP로 재분석하였다. 이 시선속도곡선과 1998년에 관측한 BVR 광도곡선을 Wilson-Devinney 방법으로 동시에 분석하였다. 그 결과 DO Cas가 접촉 또는 주성이 로쉬엽을 채우고 있는 접촉에 매우 가까운 준분리형 쌍성임을 확인하였으며 또한 이 계의 절대량을 구하였다.

• 대한디지털의료영상학회논문지
• /
• 제17권1호
• /
• pp.9-12
• /
• 2015

임상용 모니터의 출력값 중 가장 큰 영향을 주는 것이 휘도이다. 최근 컬러 모니터의 임상용 사용으로 인해 출력값의 보정은 매우 중요하게 관리되고 있다. 색보정 변위의 특성화가 휘도와 동일한 인자로 영향을 주는지 분석하기 위해 사용된 특성화 보정 모델은 GOG모델과 S-curve모델 이다. 두 개의 모델을 통해 모니터의 휘도는 장치의 출력과 직접적인 관계가 있다는 것을 증명하고 동일한 출력에 입력값을 가질 수 있도록 구성하고자 한다. 동일한 출력을 디스플레이 할 경우 동일한 출력값을 얻어야 한다. 그러나 모니터에 따라 서로 다른 출력값을 산출한다. 컬러모니터의 경우는 출력의 안정성에 휘도뿐만 아니라, 색감(R,G,B) 변화가 큰 역할을 수행한다. 본 연구에서는 분석인자 중 대조도에 영향을 주는 인자를 역추적하여 특성화 보정 S-curve모델을 LCD에 적용하였다. 이는 GOG모델을 적용한 CRT와 동일한 결과를 얻었다. 따라서 인자는 CIEXYZ의 결과값과 동일한 인자를 구할 수 있다.

• 대한치과기공학회지
• /
• 제38권3호
• /
• pp.217-224
• /
• 2016

Purpose: This study aimed to generate 3-D occlusal curvatures and evaluate the relationship between the occlusal curvatures and mandibular occlusal morphology factors. Methods: Mandibular dental casts from 25 young adult Korean were scanned as a virtual dental models with a 3-D scanner(Scanner S600, Zirkonzahn, Italy). The curve of Spee, curve of Wilson, and Monson's sphere were generated by fitting a circle/sphere to the cusp tips using a least-squares method. The mandibular mesiodistal cusp inclination, buccolingual cusp inclination, and tooth wear parameters were measured on the prepared virtual models using RapidForm2004(INUS technology INC, Seoul, Korea). Wilcoxon signed-rank test was performed to test side difference, and Spearman's rank correlation coefficients were investigated to verify the correlation between occlusal curvatures and correlated factors (a=0.05). Results: The mean radii of curve of Spee were $83.09{\pm}33.94$ in the left side and $79.00{\pm}28.12mm$ in the right side. The mean radii of curve of Wilson were $66.82{\pm}15.87mm$ in the mesial side and $47.87{\pm}9.40mm$ in the distal side with significantly difference between mesiodistal sides(p<0.001). The mean radius of Monson's sphere was $121.85{\pm}47.11mm$. Most of the cusp inclination parameters showed negative correlation for the radius of Monson' sphere(p<0.05). Especially, the buccolingual cusp inclinations in mesial side of molar showed high correlation coefficients among the factors(p<0.05). Conclusion: The radius of Monson's sphere was greater than the classical 4-inch values, and the buccolingual cusp inclinations in mesial side of molar can be considered as one of the main factors correlating with the radius of Monson's sphere.

• 대한수학회보
• /
• 제50권5호
• /
• pp.1599-1622
• /
• 2013

We show many examples of curves on the unit 2-sphere $S^2(1)$ in $\mathbb{R}^3$ and the unit 3-sphere $S^3(1)$ in $\mathbb{R}^4$. We study whether its curves are Bertrand curves or spherical Bertrand curves and provide some examples illustrating the resultant curves.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
• /
• pp.369-374
• /
• 2001

Gear is general mechanical elements that used for power transmission between two shafts that interval is comparatively short. and it delivers big power as accurate ratio of speed. The profile of Spur gear which is the most basic factor is divided into Trochoidal fillet curve and Involute curve. Involute curve is used a lot of a shaped curve of machine parts such as a gear, a scroll compressor and a collar of centrifugal pump. However, it is poor to study the modeling of Trochoidal fillet curve and the three dimensions model shaped mathematical curve. This paper describes a mathematical model of profile shifted involute gear. and this model is based on Camus's theory. We draw three dimensions gear have accurate mathematical function using ADS, VisualLISP. and To check accuracy and perfection, we make a program of checking Interference. and use for this study.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.1008-1012
• /
• 1997

This study is on a mathematical model of profile shifted involute gear, and this model is based on Camus's theory. Gear is general mechanical elements that used for power transmission between two shafts that interval is comparatively short. and it delivers bit power as accurate ratio of speed. The profile of Spur gear which is the most basic factor is divided into Trochoidal fillet curve and Involute curve. Involute curve is used a lot of a shape curve of machine parts such as a gear, a scroll compressor and a collar of centrifugal pump. However, It is poor to study the modeling of Trochoidal fillet curve and the three dimensions model shaped mathematical curve. So we draw three dimensions gear have accurate mathematical function using ADS(Automatic Drawing system), VisualLISP. To check accuracy and perfection, we make a program of checking Interference. and use for this study.

• Kyungpook Mathematical Journal
• /
• 제54권4호
• /
• pp.685-697
• /
• 2014

In this paper, we prove that there are no pseudo null Bertrand curve with curvature functions $k_1(s)=1$, $k_2(s){\neq}0$ and $k_3(s)$ other than itself in Minkowski spacetime ${\mathbb{E}}_1^4$ and by using the similar idea of Matsuda and Yorozu [13], we define a new kind of Bertrand curve and called it pseudo null (1,3)-Bertrand curve. Also we give some characterizations and an example of pseudo null (1,3)-Bertrand curves in Minkowski spacetime.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.203-204
• /
• 2021

Bacteria used in self-healing concrete, which arrest the crack, helps increasing the durability is well known. However, the survival and activity of the bacteria are precisely unknown. In this research, to know the bacteria's survival curve on the surface of the cement composite, bacteria's survival curve has been measured by CFU at different curing days. The survival curve of 3 days and 7 days curing does not show the significant differences in their survival tendency. However, the slope of death phase of 7 days curing was steeper than the 3 days of curing. This research was focused on the death phase but for further research, set of interval time will be reduced and observe the lag phase and exponential phase.