• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.11-22
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• 2019

The objective of this study was to improve the cross-sectional area and height estimation method using stream width. Stream water levels should be calculated together to simulate inundation of agricultural land. However, cross-sectional survey data of small rural rivers are insufficient. The previous study has developed regression equations between the width and the cross-sectional area and between the width and the height of stream cross-section, but can not be applied to a wide range of stream widths. In this study, cross-sectional survey data of 6 streams (Doowol, Chungmi, Jiseok, Gam, Wonpyeong, and Bokha stream) were collected and divided into upstream, midstream and downstream considering the locations of cross-sections. The regression equations were estimated using the complete data. $R^2$ between the stream width and cross-sectional area was 0.96, and $R^2$ between width and height was 0.81. The regression equations were also estimated using divided data for upstream, midstream and downstream considering the locations of cross-sections. The range of $R^2$ between the stream width and cross-sectional area was 0.86 - 0.91, and the range of $R^2$ between width and height was 0.79 ? 0.92. As a result of estimating the cross-sections of 6 rivers using the regression equations, the regression equations considering the locations of cross-sections showed better performance both in the cross-sectional area and height estimation than the regression equations estimated using the complete data. Hydrologic Engineering Center - River Analysis System (HEC-RAS) was used to simulate the flood stage analysis of the estimated and the measured cross-sections for 50-year, 100-year, and 200-year frequency floods. As a result of flood stage analysis, the regression equations considering the locations of cross-sections also showed better performance than the regression equations estimated using the complete data. Future research would be needed to consider the factors affecting the cross-sectional shape such as river slope and average flow velocity. This study can be useful for inundation simulation of agricultural land adjacent to an unmeasured stream.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.655-664
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• 1995

Sixty male patients with polysomnographically documented OSA were included in this study. A pair of cephalograms were obtained in the upright and supine positions. In the supine position, the ANB angle, lower facial height and the cross-sectional area of soft palate increased and there was a decrease in the vertical airway length and oropharynx cross-sectional area. Positional changes did not affect the cross-sectional area of tongue, but the cross-sectional area of the oropharynx decreased in the supine position. The obese group had higher AI and RDI. Maxillary unit length, C3-H, the cross-sectional areas of tongue, soft palate and oropharynx were significantly greater in the group Obese than in non-obese group. No correlation was noted between the mandibular unit length and OSA severity, The group of small mandibular unit length showed shorter lower facial height and maxillary unit length, and smaller cross-sectional area of tongue than the long mandibular unit length group. Hyold bone positioned more inferiorly and cross-sectional area of nasopharynx decreased as the OSA severity increased.

• Steel and Composite Structures
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• v.50 no.4
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• pp.419-428
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• 2024

Prefabricated partially-encased composite (PEC) structural component is widely used in construction industry due to its superior structural performance and easy assembly characteristic. However, the solid web in traditional PEC components tends to split concrete into two halves, thus potentially reduces structural integrity and requires double concrete pouring. To overcome the above disadvantages, a new PEC beam with open-web π-shaped steel is proposed in this paper. Four open-web PEC beams with varying sectional height, flange thickness and web void rate were constructed and tested under flexural loads. During experimental tests, all beams exhibited typical flexural failure modes with strong moment capacities and excellent ductility. Owing to the unique construction form of web opening, steel-concrete bonding properties were enhanced and very small relative steel-concrete slips were observed. Experimental results also showed that the flexural capacity of such PEC beams increased with the increase of the sectional height and flange thickness, while was not affected by the web void rate. At last, a flexural capacity formula of the open-web PEC beam was proposed based on the whole section plastic rule. The formula results agreed well with experimental results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.100-109
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• 2021

This study was examined the tensile strength change of a circular tubular member with artificial sectional damage on its surface to consider surface sectional damage by corrosion. The tensile strength tests were conducted using circular tubular specimens with artificial sectional damage considering sectional damaged height and width on its surface according to the corrosion level. From the tensile strength test results, it is confirmed that tensile strength of the circular tubular specimens was affected by the damaged circumference (damaged width), not damaged length (damaged height) and their tensile failures were appeared at the minimum section of the artificial sectional damage part. Nonlinear finite-element analyses were conducted considering equivalent sectional damage effect on sectional damaged part in tensile specimens to examine the change in the tensile strength of tubular specimens with artificial sectional damage since it is difficult to estimate the sectional damaged surface condition of the specimens clearly. From the nonlinear finite element analysis results for the tensile test specimens, tensile strengths of test specimens with irregular sectional damaged surface were relatively evaluated to be highly decreased than these of FE analysis model with equivalent sectional damage. Therefore, residual tensile strengths of tensile members with irregular sectional damage as local corrosion can be evaluated and predicted using correlation coefficient between tensile test results and FE analysis results with equivalent sectional damage.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.379-388
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• 2002

For the success of dental implant, accurate radiographic evaluation is prerequisite for planning the location of the osseointegrated implants and avoiding injury to vital structures. CT/MPR(computed tomography/multiplanar reformation) shows improved visualization of inferior alveolar canal. In order to obtain cross-sectional images parallel to the teeth, the occlusal plane is used to orientate for the axial plane. If the direction of axial plane is not parallel to the occlusal plane, the reformatted cross-sectional scans will be oblique to the planned fixture direction and will not show the actual dimension of the planned fixture's location. If the available bone height which measured in the cross-sectional view is much greater than the actual available bone height, penetration of canal may occur. The aim of this study is to assess the effect of the axial plane to measurement of available bone height for dental implant in computed tomography of the mandible. 40 patients who had made radiographic stents and had taken CT were selected. The sites that were included in the study were 45 molar regions. In the central panoramic scan, the length from alveolar crest to superior border of inferior alveolar canal(available bone height, ABH) was measured in direction of reformatted cross-sectional plane(uncorrected ABH). Then, length from alveolar crest to superior border of canal was measured in direction of stent(corrected ABH). The angle between uncorrected ABH and corrected ABH was measured. From each ABH, available fixture length was decided by $Br{{\aa}}nemark$ system. The results were following ; the difference between two ABHs was statistically significant in both first and second molar(p< 0.01). The percentage of difference more than 1 mm was 8.7% in first molar and 15.5% in second molar. The percentage of difference more than 2 mm was 2.0% in first molar and 6.6% in second molar. The maximum value of difference was 2.5 mm in first molar and 2.2 mm in second molar. The correlations between difference of 2 ABHs and angle was positive correlations in both first and second molar. The correlation coefficient was 0.534 in first molar and 0.728 in second molar. The second molar has a stronger positive correlation. The percentage of disagreement between 2 fixture lengths from two ABHs was 24.4% in first molar and 28.9% in second molar.

• Child Health Nursing Research
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• v.28 no.3
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• pp.176-186
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• 2022

Purpose: This study investigated the nutritional status of ethnic (belonging to minority groups) preschool children in Northern Thailand. Methods: In this cross-sectional descriptive study, the sample group included 147 parents and 147 preschool children (2-6 years old). Participants volunteered to complete a questionnaire on the personal information of children and parents, as well as family- and school-related factors. Data were analyzed using descriptive statistics, a nutritional status calculator, and logistic regression analysis. Results: A birth weight of less than 2,500 g was related to weight-for-age and weight-for-height. Not having been breastfed and having been breastfed for less than 6 months were related to weight-for-height. An elementary school education level among parents was related to children's height-for-age. Familial unhealthy food consumption for 1-2 days per week was related to weight-for-age and height-for-age. Conclusion: This study reflects the importance of nutritional care for children at the beginning of pregnancy and continuing to the preschool age, as well as the importance of breastfeeding. Families were found to be a key factor in supporting good nutrition among children.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.596-605
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• 2007

The behavior of a non-buoyant turbulent round jet discharging horizontally was investigated experimentally. The instantaneous velocity field of the jet was obtained using the particle image velocimetry (PIV) method and used to calculate the mean velocity field by phase-averaging. This study tested regular waves with a relatively small wave height for a wavy environmental flow. The centerline and cross-sectional velocity profiles were reported to demonstrate the effect of the waves on the jet diffusion in respect of wave height and wave phase. The wave phase effect was studied for three phases: zero-upcrossing point, zero-downcrossing point, trough. From the results, it is found that the centerline velocity decreases and width of the cross-sectional profile increases as the wave height increases. In addition, the self-similarity of the cross-sectional profile appears to break down although the width of each case along the axial distance does not vary significantly. The phase effect is found to be relatively small compared to the wave height effect.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.7-16
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• 1997

This study was performed to demonstrate the method of image reformation for dental implants, using a personal computer with inexpensive softwares and to compare the images reformatted using the above method with those using Dentascan software. CT axial slices of 5 mandibles of 5 volunteers from GE Highspeed Advantage(GE Medical systems, U.S.A.) were used. Personal computer used for image reformation was PowerWave 6041120 (Power Computing Co, U.S.A.) and softwares used were Osiris (Univ. Hospital of Geneva, Switzerland) and Import ACCESS V1.H Designed Access Co., U.S.A.) for importing CT images and NIH Image 1.58 (NIH, U.S.A.) for image processing. Seven images were selected among the serial reconstructed cross-sectional images produced by Dentascan(DS group). Seven resliced cross-sectional images at the same position were obtained at the personal computer(PC group). Regression analysis of the measurements of PC group was done against those of DS group. Measurements of the bone height and width at the reformed cross-sectional images using Mac-compatible computer were highly correlated with those using workstation with Dentascan software(height : r²=0.999, p<0.001, width : r²=0.991, p<0.001). So, it is considered that we can use a personal computer with inexpensive softwares for the dental implant planning, instead of the expensive software and workstation.

• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.255-264
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• 1996

This study was performed to demonstrate the method of image reformation for dental implants, using a personal computer with inexpensive softwares and to compare the images reformatted using the above method with those using Dentascan software. CT axial slices of 4 mandibles of 4 volunteers from GE Highspeed Advantage(GE Medical systems, U.S.A.) were used. personal computer used for image reformation was PowerWave 604/120 (Power computing Co, U.S.A. ) and softwares used were Osiris (Univ. Hospital of Geneva, Switzerland) and ImportACLESS Vl.1 (Designed Access Co., U.S.A.) for importing CT images and NIH image 1.58 (NIH, U.S.A.) for image processing. Seven image were selected among the serial reconstructed cross-sectional images produced by Dentascan. Seven resliced cross-sectional images at the same position were obtained at the personal computer. Regression analysis of the measurements of PC group was done against those of DS group. Measurements of the bone height and width at the reformer cross-sectional images using Mac-compatible computer was highly correlated with those using workstation with Dentascan software(height : r2= 0.999, p<0.001, width : r2= 0.993, p <0.001). So, it is considered that we can use a personal computer with inexpensive software for the dental implant planning, instead of the expensive software and workstation.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.153-158
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• 2000

Atomic Force Microscope (AFM) was used to study cross sectional profiles and dimensions of fatigue striations in 2017-T351 aluminum alloy. Their widths (SW) and heights $(SH,\;SH_h)$ were measured from the cross sectional Profiles of three-dimension AFM images. The following results that will be helpful to understand the fatigue crack growth mechanism were obtained. (1) Coincidence of the crack growth rate with the striation width was found down to the growth rate of $10^{-5}$ mm/cycle. (2) The relation of $SH={\alpha}(SW)^{1.2}$ was obtained. (3) The ratio of the striation height to its width SH/SW and did not depend on the stress intensity factor range ${\Delta}K$ and the stress ratio R. From these results, the applicability of the AFM to nano-fractography is discussed.