• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.79-88
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• 1988

The purpose of this study was to investigate the factors which might be related to mandibular third molar eruption and to predict the possibility of whether or not it will be erupted. The material of this study was lateral cephalometric radiograms, pantomograms and dental casts obtained from 70 patients (19 males, 51 females) ranging in age from 18.0 to 32.1 years. They were devided into erupted group and impacted group of mandibular third molars. For the comparison of each group, a total of 20 measurement items were employed and the data were analyzed by means of computer statistical method. As a result of this study, the following conclusion can be made; 1. The longer mandibular body length and narrower mandibular ramus width, the higher eruption tendency of the lower third molar, but the degree of genial angle was not related to mandibular third molar eruption. 2. The lower percentage of posterior mandibular body height to anterior mandibular body height, the higher eruption tendency of the lower third molar. 3. The total tooth size, including the lower second molar, appeared to be larger in the impacted group than in the erupted group of the lower third molar. 4. The arch length discrepancy of the impacted group was more severe in contrast with the erupted group of the lower third molar.

• Earthquakes and Structures
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• v.7 no.3
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• pp.333-347
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• 2014

Multi-scale model can take both computational efficiency and accuracy into consideration when it is used to conduct elasto-plastic seismic response analysis for complex steel bridges. This paper proposed a method based on pushover analysis of member sharing the same section pattern to verify the accuracy of multi-scale model. A deck-through type steel arch bridge with a span length of 200m was employed for seismic response analysis using multi-scale model and fiber model respectively, the validity and necessity of elasto-plastic seismic analysis for steel bridge by multi-scale model was then verified. The results show that the convergence of load-displacement curves obtained from pushover analysis for members having the same section pattern can be used as a proof of the accuracy of multi-scale model. It is noted that the computational precision of multi-scale model can be guaranteed when length of shell element segment is 1.40 times longer than the width of section where was in compression status. Fiber model can only be used for the predictions of the global deformations and the approximate positions of plastic areas on steel structures. However, it cannot give exact prediction on the distribution of plastic areas and the degree of the plasticity.

• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.467-477
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• 2001

This investigation was designed to determine the effects of wire size, bracket width and the number of bracket on bracket-wire dynamic frictional resistance during simulating arch wire-guided tooth movement in vitro. For simulation of an arch wire-guided tooth movement, we simulated tooth, periodontal ligament and cancellous bone. Maxillary premolar and 1st molar were simulated as real sized resin teeth, the simulated resin teeth which its root was coated by polyether impression material which its elastic modulus is similar to periodontal ligament were embedded in steel housing with inlay wax which its elastic modulus is similar to cancellous bone. Stainless steel wires in four wire size (0.016, 0.018, $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$ inch) were examined with respect to three (stainless steel) bracket widths (2.4, 3.0, 4.3mm) and the number of medium bracket(one, two, three) included in the experimental assembly under dry condition. The wires were ligated into the brackets with elastomeric module. The results were as follows : 1. In all the brackets, frictional resistance increased with increase in wire size. But, statistically similar levels of frictional resistance were observed between 0.018 inch and $0.016\;{\times}\;0.022$ inch wires in narrow bracket and also between 0.016 inch and 0.018 inch wire in wide backet. 2. The frictional forces produced by 0.016 inch wire were statistically similar levels in all the brackets. In 0.018 inch round wire, wide bracket was associated with lower amounts of friction than both narrow and medium brackets. In $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$ inch rectangular wire, wide bracket produced target friction than both narrow and medium brackets. In all the wirer, narrow and medium bracket demonstrated no statistical difference in levels of frictional resistance. 3. Frictional resistance increased with increase In number of medium bracket. 0.016 inch round wire demonstrated the greatest increment in frictional resistance, followed by $0.019\;{\times}\;0.025,\;0.016\;{\times}\;0.022$ inch rectangular wire which were similar level in increment of frictional resistance, 0.018 inch wire demonstrated the least increment. The increments of frictional resistance were not constantly direct proportion to number of bracket.

• Korean Journal of Human Ecology
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• v.12 no.1
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• pp.75-84
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• 2003

The objective of this paper was to analyse the foot type of female university students by the direct and indirect measure of foot and the measures of foot outline. The results were as follow: 1. The length and the width of foot were small and ankle slender and the modification of the big toe slight. 2. The analysis on the 16 measure items revealed five factors; the first factor was related to the width and girth of foot, the second one to the length of foot, the third one to the transformation of the little toe, the fourth one to the height of foot, the fifth one to transformation of the big toe. 3. The grouping on the shape of foot revealed three types. The inline angle of foot was the smallest in average in the type 1, while it appeared to be middle in the other types. The wider foot shapes were grouped as type 2 because their inline and outline angles of foot were the biggest in average. In the type 3, the big toe was curved a lot, since it was the largest in average. 4. From the naked eye measuring method, classification from which toe was popped-out told that Egyptian foot was 30.9%, Greek foot 27.9%. On the other hand, the instrumental method showed that Egyptian foot was 57.3%, Squared foot 35.3% and Greek foot 7.4%. 5. The result from the analysis about the traits of foot shape by the degree of the arch formation of bottom foot, showed that 33.8% had the normal foot, 66.2% slightly flat foot or middle one. There was no one with rigid flat foot. 6. The shoes size they declared were that 240cm was 33.3%, 235cm 18.1% and 245cm 18.1%. The shape of their shoe heel were flat heel(34.8%), cuban heel(25.5%), and narrow straight heel(19.9%); and that of the shoe toe were round toe(25.4%), oval toe(20.4%) and squared toe(20.4%). 7. The discomforting parts when they wear shoes were the little toe(35.4%), the rear of foot(13.9%), and the width of foot(13.9%), which was related to their dislike of shoe with the pointed toe.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.297-304
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• 2008

The purpose of this study was to evaluate a 3-Dimensional laser scanner for the space analysis after loss of a primary first molar. Six children with premature loss of a primary first molar were examined using study models taken before and after the extraction. The results were as follows: 1. There was no change in primary molar space after the extraction of a maxillary primary first molar However, 2 out of 3 children experienced primary molar space loss in extraction side of a mandibular primary first molar. 2. Arch width and arch perimeter showed no difference between initial and final model. 3. All primary canines did not show any changes in inclination. Maxillary primary second molars had similar changes in both extraction and control side. However, 2 out of 3 mandibular primary second molars in extraction side showed more lingual tipping compared to control side. Mandibular permanent first molars tipped more lingually in extraction side. 4. In angulation, primary canines showed nothing of significance. Mandibular primary second molars tipped more mesially in extraction side than in control side. Maxillary permanent first molars have increased distal angulation after extraction of primary first molars in both side.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.147-157
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• 2019

This study aimed to evaluate skeletodental characteristics of patient with maxillary lateral incisor agenesis (MLIA) in mixed dentition. It involved the children in early mixed dentition who visited Pusan National University dental hospital for orthodontic purposed and had intact primary canines. 38 children with MLIA and 38 controls with the same chronological age satisfying the inclusion criteria were selected. The craniofacial structures and dental arch dimensions of the MLIA were evaluated using model & cephalometric analysis and compared to controls. The rate of unilateral MLIA was high in male and the rate of bilateral MLIA was high in female. In model analysis, the width / length ratio of maxillary anterior portion of the MLIA group were higher and arch perimeter of the maxilla of the MLIA group were smaller than those of the control group (p = 0.003, 0.04). Cephalometric analysis showed that there were no significant differences in terms of skeletal, dental analysis. In soft tissue profile, nasolabial angle was larger in MLIAs than in controls (p = 0.039). Considering these skeletodental characteristics of MLIA, early diagnosis and proper management is highly recommended to minimize the possibility of functional defect.

• Computers and Concrete
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• v.14 no.6
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• pp.745-765
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• 2014

In this paper, it is aimed to determine the finite element model updating effects on the structural behavior of long span concrete highway bridges. Birecik Highway Bridge located on the 81stkm of Sanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The bridge consist of fourteen spans, each of span has a nearly 26m. The total bridge length is 380m and width of bridge is 10m. Firstly, the analytical dynamic characteristics such as natural frequencies and mode shapes are attained from finite element analyses using SAP2000 program. After, experimental dynamic characteristics are specified from field investigations using Operational Modal Analysis method. Enhanced Frequency Domain Decomposition method in the frequency domain is used to extract the dynamic characteristics such as natural frequencies, mode shapes and damping ratios. Analytically and experimentally identified dynamic characteristics are compared with each other and finite element model of the bridge is updated to reduce the differences by changing of some uncertain parameters such as section properties, damages, boundary conditions and material properties. At the end of the study, structural performance of the highway bridge is determined under dead load, live load, and dynamic loads before and after model updating to specify the updating effect. Displacements, internal forces and stresses are used as comparison parameters. From the study, it is seen that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %46.7 to %2.39 by model updating. A good harmony is found between mode shapes after finite element model updating. It is demonstrated that finite element model updating has an important effect on the structural performance of the arch type long span highway bridge. Maximum displacements, shear forces, bending moments and compressive stresses are reduced %28.6, %21.0, %19.22, and %33.3-20.0, respectively.

• Journal of Korea Water Resources Association
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• v.53 no.1
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• pp.29-43
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• 2020

The purpose of this study is to propose the design criteria and detailed design model by reviewing the issues related to geometry, formation process, destruction process, hydraulic function, restoration and ecological function of the step-pool from the existing research results, to apply the step-pool sequences to river restoration. Based on the analysis and review results, the design criteria for the structure and size of the step-pool are presented as ratio of the step spacing and the channel width, ratio of the unit step slope and channel slope, and ratio of step height and the particle size. To ensure structural stability of the step, stability analysis method of overturning based on the keystone theory was proposed as a design criterion. As a detailed design concept, a layout model was proposed by applying the imbricating structure of keystones and arch stones to the planar, longitudinal and transverse configurations of the step-pool.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.245-255
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• 2001

Existing cut-and-cover tunnels are designed regardless of cut-slope under the assumption that the overburden weight of backfill soil acts on tunnel arch and the earth pressure at rest acts on tunnel walls. However, actual earth pressures acting on the tunnel lining depend on open-cut size composed of cut-slope and cut-width, and thus the tunnel lining shows a different structural behavior. This study investigated the effect of cut-slope on structural behavior of the cut-and-cover tunnel lining as follows; Firstly, a comprehensive numerical analysis method using FLAC2D code was used and verified by field measurements of tunnel profile. Secondly, based on the verified numerical analysis technique, earth pressure acting on the lining, and displacement and sectional force developed on the lining were estimated with various shapes of cut-slopes$30^{\circ}\;, 456{\circ},\; 60^{\circ},\; and\;75^{\circ}%). Numerical analysis results indicate that the steeper cut-slope shows the more displacement and moment of the tunnel lining.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.2
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• pp.21-28
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• 1986

This paper is concerned with the mutual relationship among interpressure, last. foot within a new shoe and foot within a fifty-hour-used shoe at the standing posture at three different heel-heights 1. The interrelationship between the heel-heights and interpressure is very significant at the level of $0.1\%$. The heel-heights cause high interpressure at different parts of foot; heel point and big toe point in a 3 cm-heel shoe, big toe point and heel outside joint point in a 5 cm-heel shoe, and little toe point, heel-outside joint point, and arch point in a 7 cm-heel shoe. 2. Foot girth and foot width measurements either within a new shoe or within a fifty-hour-used shoe significant at the level of $5\%,\;1\%,\;0.1\%$ and show discrepancies at three different heel heights; the part between instep and ball joint in a 3 cm-heel shoe, toe part in a 5 cm-heel shoe, heel-inside joint. heel-outside joint and toe part in a 7 cm-heel shoe are highly influenced by heel heights. The higher the shoe-hee15 are, the more heavily the fore part of foot is pressured in lateral direction because shoe is made to have high instep from a fashion viewpoint. Higher shoe heels prevent weight pressure from being concentrated on heel. If shoe heels are toe high, people in such shoes feel easily tired. It is very worthy of note in selecting shoes to consider not only the shoe fashion but also fore shoe type, heel height, and shoe material with proper elasticity.