• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.471-478
• /
• 2000

Ground movements are inevitably caused by tunnel construction in soft ground. In the design and construction of tunnels in urban areas, the potential effects of buried pipelines by ground movements are one of the important design cosiderations. Generally, the most common modes of failure of buried pipelines due to ground movements are tensile fracture of main pipelines, rotation angle and pull-out displacement at joints. In the parametric study, a wide range of conditions were considered, including tunnel diameter(D), tunnel depth(Z$\sub$0/), volume loss(V$\sub$ι/) and inflection point(i). Based on this results, design charts, which are applicable to assess potential damage of buried pipelines associated ground movements due to tunnelling, are developed.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.1
• /
• pp.10-19
• /
• 1989

This paper proposes the object modeling algorithm using depth data. In order to extract the shape of the object, surface is classified by the magnitude and the direction of Z gradient within the 2x2 mask from input depth data. For the object combined with several primitives is separated by kernel points. Further, spatial relationship between surface regions is extracted for the recognition. Finally, the effectiveness of this algorithm is demonstrated by several experiments.

• 한국가시화정보학회:학술대회논문집
• /
• 2001.12a
• /
• pp.100-107
• /
• 2001

A simple new technique of particle depth position measurement, which can be applied for three-dimensional velocity measurement of fluid flows, is proposed. Two color illumination system that intensity is encoded as a function of z-coordinate is introduced. A calibration procedure is described and a profile of small sphere is detected by using the present method as preliminary test. Then, this method is applied to three-dimensional velocity field measurement of simple flow fields seeded with tracer particles. The motion of the particles is recorded by color 3CCD camera. The particle position in the image plane is read directly from the recorded image and the depth of each particle is measured by calculation of the intensity ratio of encoded two color illumination. Therefore three-dimensional velocity components are reconstructed. Although the result includes to some extent error, the feasibility of the present technique for three-dimensional velocity measurement was confirmed.

• The Journal of Korea CHUNA Manual Medicine
• /
• v.6 no.1
• /
• pp.21-30
• /
• 2005

Objectives : This study was designed to find The characteristics of the Moire topography in patients of HIVD of Cx-spine. Methods : The Moire topography using IBS(Intek-plus Body Scanner 2000, Seoul, Korea) were obtained in 688 people of control group and 105 patients of HIVD of Cx-spine. Each values were studied to determine the difference between controls and patients. Results : There were significantly difference between controls and patients in thoracic ratio, lumbar ratio, top of the thoracic depth ratio, top of the lumbar depth ratio, Z axis distance and DZ/DY. Conclusions : There were increase of the thoracic kyphosis and lower position in top of the thoracic kyphosis in patients of HIVD of Cx-spine than controls.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05b
• /
• pp.792-795
• /
• 2010

본 논문에서는 공간감을 극대화 시킬 수 있는 영상의 표현에 관하여 사례연구를 통해 입체영상의 공간감에 관하여 논하고자 한다. 이를 위하여 일반적인 영상에서의 공간감 창출과 입체영상에서의 공간감차이에 관하여 알아보고, 이를 사례분석을 통하여 서로 다른 표현 방식에 관하여 논하고자 한다.

• Journal of the Korean earth science society
• /
• v.26 no.7
• /
• pp.706-713
• /
• 2005

Subsurface oceanic data (Z20; Depth of $20^{\circ}C$ isotherm and WWV; Warm Water Volume) from the tropical Pacific Ocean from 1980 to 2004 were utilized to examine upper ocean variations in relation to E1 Nino. Time series analysis using EOF, composite, and cross-correlation methods indicated that there are significant time delays between subsurface oceanic parameters and the Nino3.4 SST. It implied that Z20 and WWV would be more reliable predictors of El Nino events. Based on analyzed results, we also constructed neural network model to predict the Nino3.4 SST from 1996 to 2004. The forecasting skills for the model using WWV were statistically higher than that using the trade wind except for short range forecasting less than 3 months. This model greatly predicted SST than any other previous statistical model, especially at lead times of 5 to 8 months.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.2
• /
• pp.93-100
• /
• 2018

PURPOSE. The purpose of this study was to determine the changing frequency of a diamond bur after multiple usages on 3 different surfaces. MATERIALS AND METHODS. Human premolar teeth (N = 26), disc shaped direct metal laser sintered CoCr (N = 3) and zirconia specimens (N = 3) were used in this study. Groups named basically as Group T for teeth, Group M for CoCr, and Group Z for zirconia. Round tapered black-band diamond bur was used. The specimens were randomly divided into three groups and placed with a special assembly onto the surveyor. 1, 5, and 10 preparation protocols were performed to the first, second, and third sub-groups, respectively. The subgroups were named according to preparation numbers (1, 5, 10). The mentioned bur of each group was then used at another horizontal preparation on a new tooth sample. The same procedure was used for CoCr and zirconia disc specimens. All of the bur surfaces were evaluated using roughness analysis. Then, horizontal tooth preparation surfaces were examined under both stereomicroscope and SEM. The depth maps of tooth surfaces were also obtained from digital stereomicroscopic images. The results were statistically analyzed using One-Way ANOVA, and the Tukey HSD post-hoc tests (${\alpha}=.05$). RESULTS. All of the groups were significantly different from the control group (P<.001). There was no significant difference between groups Z5 and Z10 (P=.928). Significant differences were found among groups T5, M5, and Z5 (P<.001). CONCLUSION. Diamond burs wear after multiple use and they should be changed after 5 teeth preparations at most. A diamond bur should not be used for teeth preparation after try-in procedures of metal or zirconia substructures.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.26 no.5
• /
• pp.291-296
• /
• 2006

The residual stress in shot-peened Al 7075 alloy was evaluated using surface acoustic wave (SAW). Shot peening was conducted to produce a variation in the residual stress with the depth below the surface under a shot velocity of 30 m/s. The SAW velocity was measured from the V(z) curve using a scanning acoustic microscopy (SAM). The Vickers hardness profile from the surface showed a significant work hardening near the surface layer with a thickness of about 0.25 mm. As the residual stress became more compressive, the SAW velocity increased, whereas as the residual stress became more tensile, the SAW velocity decreased. The variation in the SAW velocity through the shot peened surface layer was in good agreement with the distribution of the residual stress measured by X-ray diffraction technique.

• Restorative Dentistry and Endodontics
• /
• v.46 no.3
• /
• pp.39.1-39.12
• /
• 2021

Objectives: This study analyzed the physical-chemical behavior of 2 bulk fill resin composites (BFCs; Filtek Bulk Fill [FBF], and Tetric-N-Ceram Bulk Fill [TBF]) used in 2- and 4-mm increments and compared them with a conventional resin composite (Filtek Z250). Materials and Methods: Flexural strength and elastic modulus were evaluated by using a 3-point bending test. Knoop hardness was measured at depth areas 0-1, 1-2, 2-3, and 3-4 mm. The translucency parameter was measured using an optical spectrophotometer. Real-time polymerization kinetics was analyzed using Fourier transform infrared spectroscopy. Results: Flexural strength was similar among the materials, while TBF showed lower elastic modulus (Z250: 6.6 ± 1.3, FBF: 6.4 ± 0.9, TBF: 4.3 ± 1.3). The hardness of Z250 was similar only between 0-1 mm and 1-2 mm. Both BFCs had similar hardness until 2-3 mm, and showed significant decreases at 3-4 mm (FBF: 33.45 ± 1.95 at 0-1 mm to 23.19 ± 4.32 at 3-4 mm, TBF: 23.17 ± 2.51 at 0-1 mm to 15.11 ± 1.94 at 3-4 mm). The BFCs showed higher translucency than Z250. The polymerization kinetics of all the materials were similar at 2-mm increments. At 4-mm, only TBF had a similar degree of conversion compared with 2 mm. Conclusions: The BFCs tested had similar performance compared to the conventional composite when used in up to 2-mm increments. When the increment was thicker, the BFCs were properly polymerized only up to 3 mm.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.4
• /
• pp.61-66
• /
• 2023

In the past, purchasing limited products was nothing more than purchasing expensive luxury goods. However, the current 'Limited product purchase' is not just pay to ability, but the information to purchase the product are important factors. Therefore, this study aims to find out 1) the motivation to purchase limited edition products and 2) the effect of the motivation on the consumer's experience(price, intention to purchase). As a result, five major purchase motives(Conformity, Interest, Scarcity, Finance technology, Desire to concede) were found. Among them 'Interest' had a positive effect on the product purchase price, and 'Conformity' had a negative effect on the product price. Next, 'Interest' and 'Scarcity' had a positively significant effect on intention to purchase. Through this study, we were able to reveal in depth the actual purchase motives of consumers who are currently emerging as the main age group of the new consumption culture, and expect these purchase motives to be actively used in the new market such as resell markets.