• The Korean Journal of Pain
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• v.12 no.1
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• pp.114-118
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• 1999

Backgrouds: Cervical epidural blocks were used as part of a comprehensive multimodal treatment program for patients with chronic pain in the head, neck and upper extremities. The depth of the epidural space beneth the skin surface varies at different levels of the spinal column in the same patient. It also varies from patient to patient at the same vertebral level. We studied the distance the skin to the cervical epidural space in adults patients at different intervertebral spaces. Methods: Date were gathered from 628 patients having cervical epidural block for relief of cervical and upper extrimity pain. All blocks were performed using hanging drop method after loss of resistance with saline at C5-6, C6-7, C7-T1 intervertebral space. Results: Mean distances for skin to cervical epidural space (DSES) were 5.42 cm, 5.06 cm, 4.68 cm in male, 5.00 cm, 4.61 cm, 4.10 cm in female at C7-T1, C6-7, C5-6 intervertebral space. DSES correlated with body weight, neck circumference and body mass index significantly. Conclusion: In the cervical spine, DSES varies from space to space. The longest DSES were noted at C7-T1 level in male, and the shortest DSES were at C5-6 in female. DSES has significant relationships with weight, neck circumference and body mass index.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.689-711
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• 2001

The purpose of this study was to compare clinical results of guided tissue regeneration(GTR) using either a nonresorbable ePTFE membrane or a resorbable membrane made from a synthetic copolymer of glycolide and lactide(PLGA) in the treatment of human class Ⅱ furcation defects. The ePTEE membranes were applied to 16 patients with maxillary molar buccal class Ⅱ furcation defects as Group I, PLGA membranes were applied to 15 patients with maxillary molar buccal class Ⅱ furcation defects as Group Ⅱ, ePTFE membranes were applied to 20 patients with mandibular molar buccal class Ⅱ furcation defects as Group Ⅲ and PLGA membranes were applied to 20 patients with mandibular molar buccal class Ⅱ furcation defects as Group Ⅳ and bone graft materials(DFDBA) were applied in all groups. Probing depth, gingival recession, clinical attachment level, tooth mobility and sulcus bleeding index(SBI) were measured at baseline, 3, 6 and 12months postoperatively. In addition, membrane exposure levels were measured at surgery, 1, 2 and 6weeks postoperatively and postoperative complications were evaluated. The results were as follows: In all groups, there were statistically significant differences in probing depth reduction, gain of clinical attachment and mobility reduction at values of 3, 6 and 12months postoperatively compared to values of baseline, whereas no significant differences in SBI except Group I and gingival recession(p<0.05). Membrane exposure levels were increased at 1, 2 and 6weeks postopratively compared to value of baseline in Group I(p<0.05). There were no statistically significant differences between ePTFE and PLGA membrane in probing depth, clinical attachment level and SBI. There were minimal gingival recession and membrane exposure in Group Ⅳ and pain and swelling were the most common postoperative complications in Group Ⅱ, Ⅲ(p<0.05). In conclusion, this study showed that both nonresorbable membrane and resorbable membrane were effective similarly in the treatment of class Ⅱ furcation defects, without statistical differences in clinical measurements.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.165-177
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• 1994

To investigate the depth of the root concavity and root surface area of the maxillary first premolar, 40 maxillary first premolars were used. All the teeth which extracted because of advanced periodontal disease and orthodontic treatment procedure, were sectioned every 1.5mm from cementoenameljunction to the apex with hard tissue microtome. Each sectioned root was taken photograph with slide film, and projected for measuring with a calibrated digital Curvi-Meter. The root surface area, percentage of the RSA and the linear variation of the RSA were calibrated for each 1.5mm section. Linear variation of the depth of root concavity was measured on mesial and distal root surface for each section using computer-aided digitizer. The results were as follows. 1. The total mean root length of maxillary first premolar was 13.48mm. Mean buccal root length of 2-rooted tooth was 12.59mm, mean palatal root length was 12.73mm, and mean root length of single rooted tooth was 13.78mm. 2. The total mean root surface area of maxillary first premolar was $194.17mm^2$, mean root surface area for 2-rooted tooth was $205.97mm^2$ and mean root surface area for single rooted tooth was $188.49mm^2$. 3. It was 59.93% of the total root surface area that the area from CEJ to coronal 6mm. And, the coronal half of the root length accounted for approximately 71.76% of the total root surface area. 4. Most deepest concavity of the mesial root surface was 0.65mm at apical 3.0mm, 4.5mm level in maxillary first premolar. And, that of the distal root surface was 0.37mm at apical 4.5mm level. 5. All of the maxillary first premolar had mesial root surface concavity. This mesial root surface concavity appeared to be more pronounced in 2-rooted tooth than single rooted tooth.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.631-642
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• 2013

The standard CPT(Cone Penetration Test), which can be easily performed to investigate in-situ soil engineering properties, has been widely used. CPT are also widely being utilized in centrifuge model tests. In this study, a miniature cone with 10mm diameter was developed and its applicability in the centrifuge was evaluated. The developed miniature cone was equipped with a four degree-of-freedom in-flight robot. A series of cone penetration tests was performed under four centrifuge acceleration levels. As results, the cone resistances measured at the same confining stress within shallow penetration depth were affected by the centrifugal accelerations. The critical depth was proportional to the cone diameter and relative density. Cone resistances results below the critical depth and soil parameters obtained from the laboratory tests were compared with those by previously proposed empirical relations.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.9-18
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• 2021

In this study, the overconsolidation ratio (OCR) of soft clay soil was calculated by conducting an indoor physical experiment and a dynamics test using undisturbed soil samples from a soft clay soil field in South Korea. The OCR by depth was predicted by comparing the experimental results with the existing empirical equations. Methods using the liquidity index and the existing empirical equation by the Naval Facilities Engineering Systems Command (NAVFAC) were examined, and the results were compared with the actual measured values. The method using the liquidity index was found to be suitable for estimating the rough OCR of the ground. However, the effect of drying was not considered for the ground above the groundwater level. Therefore, an equation for the correlation equation between the depth and OCR of each region, including the ground above the groundwater level, was proposed. The proposed equation was applied to the OCR prediction of the adjacent area. The predicted values in the area composed of clay (CL, CH) were found to be in good agreement with the actual values. In the region composed of silt (ML), however, the predicted values were not consistent with the actual values. This suggests that the sedimentation and compositional characteristics, rather than the engineering characteristics of the soil, are important factors that affect the OCR prediction.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.386-391
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• 2006

Though a variety of demands for an green dwelling, it is hard to diffuse a wooden house due to high construction cost. So this study aims to diffuse to propose a space modular for production and supply. Therefore the result of investigation to the space modular of each room through the survey of width and depth in the type of dwelling in korea is as follows. 1) Investigated the mixture of magnitude on the total width and depth, the survey is showed commonly 3.6m and 4.2m. 2) Once the depth is 3.6m, a living room and inner room, room's width is 3.9m, 4.5m. Once the depth is 4.2m, those width is 4.8m. 3) By use of a survey, the post distances consisted of all rooms are 3.6m, 3.9m, 4.2m, 4.5m, 4.8m. The result of investigation to possibility for mixture applied to six level types invested post modules to the wooden house of post & Beam method is as follows. 1) With the regularity of depth and simplicity of width, It is potential to compound floor plan in korea. 2) It is possible to plan an informal shape of kitchen+dining room which is a spare space available for the merit changeable space after arranged main rooms. 3) It is possible to plan a space through a variety of mixture method at bathroom. Thus, it is possible for a variety of floor formations to build a low-cost wooden house through five types of post distance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.3
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• pp.398-407
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• 1999

In the present image processing technique, the concept of the gradient indicator(GI) has been introduced to find out the depth-of-field in sizing large particles ranging from $30{\mu}m$ to $30{\mu}m$ where using of the concept of the normalized contrast value(VC) is not appropriate. The gradient indicator is defined as the ratio of the local value to the maximum possible value of the gray-level gradient in an image frame. The gradient indicator decreases with the increases of the particle size and the distance from the exact focal plane. A particle is considered to be in focus when the value of the gradient indicator at its image boundary stays above a critical value. This critical gradient indicator($GI_{critical}$) is defined as the maximum gradient indicator($GI_{max}$) subtracted by a constant ${\Delta}GI$ which is to account for the particle-size effect. In the present ca.so, the value of ${\Delta}GI$ was set to 0.28 to keep the standard deviation of the measured particles mostly within 0.1. It was also confirmed that, to find the depth-of-field for small particles(${\leq}30{\mu}m$) with the same measurement accuracy, tho concept of the critical normalized contrast($VC_{critical}$) is applicable with 85% of the maximum normalized contrast value($VC_{max}$). Finally, the depth-of-field was checked for the size range between $10{\mu}m$ and $300{\mu}m$ when the both in-focus criteria ($GI_{critical}$ and $VC_{critical}$) were adopted. The change of the depth-of-field with the particle size shows good linearity in both the VC-applicable and the GI-applicable ranges with a reasonable accuracy.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.7
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• pp.52-61
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• 1992

An iterative scheme for computing the three-dimensional position and the surface orientation of an opaque object from a singel shaded image is proposed. This method demonstrates that calculating the depth(distance) between the camera and the object from one shaded video image is possible. Most previous research works on $'Shape from Shading$' problem, even in the $'Photometric Stereo Method$', invoved the determination of surface orientation only. To measure the depth of an object, depth of the object, and the reflectance properties of the surface. Assuming that the object surface is uniform Lambertian the measured intensity level at a given image pixel*x,y0becomes a function of surface orientation and depth component of the object. Derived Image Irradiance Equation can`t be solved without further informations since three unknown variables(p,q and D) are in one nonlinear equation. As an additional constraints we assume that surface satisfy smoothness conditions. Then equation can be solved relaxatively using standard methods of TEX>$'Calculus of VariationTEX>$'. After checking the sensitivity of the algorithm to the errors ininput parameters, the theoretical results is tested by experiments. Three objects (plane, cylinder, and sphere)are used. Thees initial results are very encouraging since they match the theoretical calculations within 20$\%$ error in simple experiments.> error in simple experiments.

• Journal of Korea Game Society
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• v.13 no.2
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• pp.99-110
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• 2013

As volume rendering has been applied for computer game, the visualization of volume data with surface data in one scene has been required. Though a hybrid rendering of volume and surface data have been developed using the GPGPU functionality, computer games which run on low-level hardware are difficult to perform the hybrid rendering. In this paper, we propose a new hybrid rendering based on DirectX 9.0 and general hardware. We generate the layered depth images from surface data using a new method to reduce the depth complexity and generation time. Then, we perform the hybrid rendering using the layered depth images. In the rendering process, we suggest a new method to transform the coordinate system from a surface coordinate to a volume coorinate and propose an accelerated rendering technique. As the result, we can perform volume-surface hybrid rendering in an efficient way.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.42-48
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• 1990

Experiments were conducted to investigate the soil freezing depth and pattern with freezing measuring instruments during 1988-l989 winter season in Kangwon province. Freezing measuring instrument was made with acrylic pipes which were consisted of inner and outer parts. Inner pipe was filled with 0.01 % methylene blue solution and rubber hose to protect pipe breakdown by solution freezing. Freezing measurements were carried out by observing discoloration of methylene blue solution. Moisture content of evergreen trees and ground cover plants was also examined in the winter season. The observed results are as follows: 1.In the land of I OOM above sea level, soil freezing depth became deeper as the sum of Accumulated degree-days of temperature below 0˚C(0˚C . day) increased: Soil freezing depth was 30-40cm at l00˚C, 42-43cm at 150˚C, and 47cm at 200˚C day 2.Soil freezing with vinyl mulching was less developed by l3cm at l00˚C with sum of subzero temperature, by l7cm at 200˚C than that of the bare ground. Soil of rich hulls mulching with 4Ocm was not frozen until soil freezing at the bare ground was developed to 25cm depth. 3.Cashmeron mulching was more effective than felt mulching in the heat insulation of soil. 4.Thawing of soil was done from the lowest part of the frozen in the ground to upward in the beginning and after that it was done from the surface of frozen soil to downward. Finally thawing was completed at the middle of frozen soil.