• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.15-23
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• 2009

Masonry structures that are very strong in compression fail due to the instability of structural shape of geometry rather than the material stress limit. Considering such structural behavior, the use of the limit theorem that focuses on structural collapse mechanisms is more appropriate for the evaluation of the structural safety of stone voussoir arch bridges. This paper is to investigate structural performance of the stone arch bridges constructed using dry construction method in Korea based on the limit theorem and to exploit the result to develop a system for an structural safety margin. It is expected that this study will help us understand structural behavior of stone voussoir arch bridges in Korea. Also, it will provide a guideline to make engineering decision from the viewpoint of the maintenance of cultural heritages.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.308-313
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• 1995

Drosophila melanogaster, D. simulans, and D. sechellia are closely related species which belong to the D. melanogaster complex; the first two cosmopolita and the last one restricted to th Seychelles archipelago. The phenogenetical relationship between this complex and their hybrids were investigated by the comparison of sex-comb tooth number an genital arch of male. In interspecific hybrids of all crosses between three species four hybrid males were produced and completely sterile. Males of D. simulans (${O}_{9}$) have significantly less sex-comb teeth (mean 8.35) than either D. melanogaster (OR, mean 10.73) and D. sechellia (Ja, mean 10.60). From the analysis by the number of sex-comb tooth in interspecific hybrids we could not represent the direction of heredity nature. each species of D. melanogaster complex were characteristic in the shape of the genital arch, which readily allows these species to be distinguished. The common structure of the genital arch in the interspecific hybrids were mosaic-like structure between parental species.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.343-352
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• 2005

In this study, the existing methods proposed to estimate the relaxed load due to a tunnel excavation are compared and analyzed. Also a new approach, by which the stress relaxed zone around an excavated tunnel periphery can be systematically estimated, was suggested for the design of 2-arch tunnel lining. To this end, local factors of safety are calculated from the redistributed stresses after the excavation of a tunnel. The height of the relaxed load is inferred based on the assumption that the stress relaxed zone might coincide with the region corresponding to the local safety factor of 2.0 or 3.0. The new approach proposed in this study has the advantage of estimating the height of the relaxed load independent of the shape of a tunnel and the ground conditions, Since the height of the relaxed load is estimated according to the local factor of safety, which is a relatively clear criterion, the designer's subjectivity involved in the design of concrete tunnel lining might be reduced.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.98-129
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• 1995

The purpose of this study was to evaluate how mandibular implant-supported fixed complete prosthesis, implant and mandible responded mechanically, according to curvature of arch, number and location of fixture, and amounts of load. The shape of mandibular arch was tapered or square form and, 4 or 6 fixtures were implanted in each arch model. A vertical load of 10kg was applied at the center of prosthesis and a vertical load of 20kg was applied at the location of the 10mm or 20mm cantilever posterior to the most distal implant. Three-dimensional finite element analysis was performed for stress distribution and deflection using commercial software(ABAQUS program) for Sun-SPARC Workstation. The results were as follows : 1. The case square arch form was more stable to compare with that of tapered arch form in respect of stress distribution and displacement under vertical load on the center of prosthesis. 2. 6-implants cases were more stable than 4-implants cases for decreasing bending torque under vertical load on the center of prosthesis. 3. Under vertical load on cantilever extension, the case of 10mm long cantilever was more stable than that of 20mm long cantilever in respect of stress distribution and displacement. 4. Under vertical load on cantilever extension, 6-implants cases had a tendency to reduce displacement and to increase the reaction force of supporting point due to increasing of the bending stiffness of the prosthesis than 4-implant case. 5. When the ends of 10mm or 20mm long cantilever were loaded, the most distal implant was under compressive stress but the second most distal implant was under the highest tensile stress and the remaining implants were under varying tensile stress. 6. Because 6-implants cases had smaller displacement than 4-implants cases, 6-implants cases were more favorable in respect of prevention of screw loosening under repeated loadings.

• Computers and Concrete
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• v.10 no.3
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• pp.277-294
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• 2012

The aim of the study is to determine the modal parameters of a prototype damaged arch dam by operational modal analysis (OMA) method for some damage scenarios. For this purpose, a prototype arch dam-reservoir-foundation model is constructed under laboratory conditions. Ambient vibration tests on the arch dam model are performed to identify the modal parameters such as natural frequency, mode shape and damping ratio. The tests are conducted for four test-case scenarios: an undamaged dam with empty reservoir, two different damaged dams with empty reservoirs, and a damaged dam with full reservoir. Loading simulating random impact effects is applied on the dam to crack. Cracks and fractures occurred at the middle of the upper part of the dams and distributed through the abutments. Sensitivity accelerometers are placed on the dams' crests to collect signals for measurements. Operational modal analysis software processes the signals collected from the ambient vibration tests, and enhanced frequency domain decomposition and stochastic subspace identification techniques are used to estimate modal parameters of the dams. The modal parameters are obtained to establish a basis for comparison of the results of two techniques for each damage case. Results show that approximately 35-40% difference exists between the natural frequencies obtained from Case 1 and Case 4. The natural frequencies of the dam considerably decrease with increasing cracks. However, observation shows that the filled reservoir slightly affected modal parameters of the dam after severe cracking. The mode shapes obtained are symmetrical and anti-symmetrical. Apparently, mode shapes in Case 1 represent the probable responses of arch dams more accurately. Also, damping ratio show an increase when cracking increases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.3
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• pp.191-200
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• 2021

This paper deals with the boundary conditions of the stress resultants at the mid-arc for free vibration analyses of the arch. The considered arch is a horseshoe symmetric elliptic arch. The work dealing with the boundary conditions of the deflection at both ends of the arch has already been reported in the open literature. This revisited paper aims to study the suitability of the boundary conditions of the stress resultants at the mid-arc to be replaced by the boundary condition at both ends. In this study, the boundary conditions of the stress resultants at the mid-arc are newly derived based on the theory of the previous work, and natural frequencies and mode shapes are obtained using the new boundary conditions of the stress resultants. The numerical results of this paper confirm that the new boundary conditions have been validated according to previous studies and results of finite element ADINA.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.593-604
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• 1995

Mandibular incisor crowding is one of the most common features of malocclusion and is interesting characteristic in view of relapse and stability after orthodontic treatment. There are many potential factors in the etiology of lower anterior crowding. The tooth size variation is one of them, but biologic significance for the faciolingual width of the teeth has been overlooked. Peck and Peck reported that persons with ideal mandibular incisor alignment were shown to have incisor with smaller mesiodistal and larger faciolingual dimensions than persons with incisor crowding. On the basis of these findings they suggested MD/FL index as a clinical guideline for the assessment for lower incisor crowding. The present study was undertaken to examine the relationship between mandibular incisor crowding and mandibular incisor dimension, and determine their correlation with arch length discrepancy. 154 dental casts of people from 11 to 17 years of age were made, and were divided into normal group with irregularity index less than of 1, and crowding group with irregularity index greater than 1.The casts were measured and analyzed statistically. The results were as follows. 1. The mean mesiodistal width for mandibular incisor was larger in crowding group, and has significant difference in central inciosr measurement. There are no significant differences in the faciolingul width and MD/FL index. 2. Irregularity index has significant correlation coefficients with mesiodistal width and MD/FL index for mandibular incisor in crowding group, but no correlation with faciolingual width. It also has correlation with maxillary and mandibular arch length discrepancy, total tooth material, mandibular intercanine width, and mandibular inter first premolar width. 3. Upper and lower arch length discrepancy have significant correlation with mesiodistal width of mandibular incisor and overbite, but have no correlation with faciolingual width. Lower arch lenth discrepancy has significant correlation with MD/FL index for mandibular incisor and upper arch length discrepancy has correlation with MD/FL index for mandibular lateral incisor. 4. Significant differences were observed between normal and crowding group for the mandibular arch length discrepancy and overbite.

• Journal of Naturopathy
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• v.11 no.1
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• pp.39-50
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• 2022

Background: It is essential to investigate the functionality of the newly developed knobble shoe. Purpose: The purpose was to explore how the body shape and balance change when wearing knobble shoes. Methods: Nine subjects wearing knobble shoes after walking for a month were analyzed. Results: For knobble shoes, we created various small air pockets in the insole to stimulate the soles of the feet to induce body changes. In particular, it was to promote the arch part of the foot by making a large lump inside and outside the center of the foot's arch. After wearing knobble shoes and using them for 30 days, the average blood sugar decreased by 31.1 mg. The lowering range was 5 to 120 mg. In one patient, the result of the hemoglobin test decreased by 7.5% to 6.5%. In the shoulder tapping test for a body balance test, seven subjects leaned to the right in a barefoot state, and two people to the left. However, after wearing shoes, all of them maintained equilibrium. knobble shoes fit, and balance was all stable. There were two subjects with a short left and four subjects with a short right. Conclusions: Blood sugar decreased after wearing the knobble shoes. The deformed shape of the body was restored to its original state by the knobble supporting the foot arch area. The balance of the sole directly affects the overall posture.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.108-111
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• 1992

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.287-294
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• 2011

Purpose: Reduction malarplasty is one of the common aesthetic procedures performed in the Orient. We have analyzed effective operative methods according to the pivot point for the osteotomy and reposition of the zygoma for reduction malarplasty after confirming the shapes of the individual zygomas. Methods: Thirty-six patients had been received malarplasty over the last 10 years. The average follow-up period was 16 months. We categorized the patients into three groups according to their prominent appearance features. Group I had a prominently protruded zygomatic body, group II had a prominently protruded zygomatic arch, and group III had a prominently protruded body and zygomatic arch. In the group I, two parallel oblique osteotomies on the body, the middle portion was removed, and with the zygomatic arch as the pivot point, the body was repositioned inwards. In the group II, the zygomatic body and arch osteotomy is performed, with the body as the pivot point, and the arch is depressed medially. In the group III, using the two aforementioned methods, the zygoma was repositioned medially. In each case, postoperative complications and patients satisfaction over the surgery were surveyed. Results: Each group had 25, 5 and 12 patients respectively. No significant complications were found except for one patient who experienced a non-union of zygomatic bone. In the case of group I, four patients underwent a secondary operation. Conclusion: Reduction malarplasty is popular as an effective facial contouring surgery. In order to obtain more effective results,however, the zygomatic shape should be identified, and appropriately repositioned by different operative technique according to pivot points.