• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.189-194
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• 2014

Purpose: The purpose of this study was to compare the clinical and radiologic results of arthrodesis between anterior approach and transfibular approach arthrodesis in ankle arthritis. Materials and Methods: There were 61 cases of ankle arthritis treated by anterior or transfibular ankle arthrodesis in our hospital from April 2008 to March 2012. We investigated 29 cases (27 patients) who underwent ankle arthrodesis with an anterior approach (15 cases) and transfibular approach (14 cases), and were followed for over two years. Clinically, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, pain visual analogue scale (VAS), and subjective satisfaction degrees were evaluated. In addition, ankle coronal and sagittal alignments were evaluated using plain radiographs at 6 and 24 months, postoperatively. Results: Clinically, preoperative mean AOFAS score and VAS was 41.3 and 6.4, and were changed to 58.9 and 3.3 postoperatively in the anterior approach group. In the transfibular approach group, preoperative mean AOFAS score was 36.6 and VAS was 7.1, and they were changed to 54.9 and 3.4 postoperatively. However, no significant differences in the clinical results were observed between the two groups (p=0.297). Duration of attaining union was 8.1 weeks in the anterior approach group and 10.4 weeks in the transfibular approach group. Complications were delayed union in one case, nonunion in three cases, cancellous screw breakage in three cases, and complex regional reflex syndrome in one case. Conclusion: After transfibular ankle arthrodesis as treatment of ankle osteoarthritis, the tendency for valgus angulation of the ankle at the final follow-up was observed and 6.5 mm cancellous screw breakage occurred frequently. Therefore, in order to achieve better stability, it is necessary to use 6.5 mm cannulated screws rather than 6.5 mm cancellous screws for ankle arthrodesis.

• Journal of Technologic Dentistry
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• v.34 no.3
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• pp.227-235
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• 2012

Purpose: This study compared the surface hardness (Vickers) and microstructural characteristics between a type IV stone with and without die hardening treatment, a polyurethane die material. Methods: Materials used were a type IV stone(MG Crystal Rock), two die hardeners (Hardening bath, Epox-it), and a polyurethane resin material(Polyluck). Six specimens per group were prepared according to manufacturer's directions. The prepared specimens were tested by means of hardness test, one-way ANOVA analysis, scanning electron microscopic(SEM) observations and energy dispersive spectroscopic(EDS) analysis. Results: In the hardness test and its statistical analysis, there was no significant difference in the surface hardness between a type IV stone and type IV stone with die hardener coating, type IV stone mixed with an epoxy like material instead of water. In contrast, polyurethane resin material exhibited significantly greater surface hardness than other specimen groups (p<0.05). Conclusion: By considering the results of the hardness test, SEM observations and EDS analysis, although the die hardeners on type IV stone did not show remarkable improvement in surface hardness, the die hardener coating on the surface of type IV stone material did show decrease of microporous and improvement of surface defects.

• Journal of the Economic Geographical Society of Korea
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• v.4 no.1
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• pp.19-35
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• 2001

This paper is concerned with the relationships between large firms with global reaches in their markets and subcontracting firms, mostly small and medium-sized firms. It then attempts to focus in more detail on the dynamic relational dimensions between the two. In doing so, we draw upon the secondary data and the results of interviewing survey with some senior managers. The empirical study shows that the localisation of subcontracting networks have been increasingly reinforced thanks to the increasing tendency of vertical disintegration by LC. However, it is identified that there is a tendency that local subcontractors are specialised in producing relatively low value-added and low technology-intensive electronic parts/components. Based on these results, the author suggests the implications of regional economic development in the context of innovation and learning.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.255-261
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• 2005

The purpose of this paper is to analyze transport ability of Automated Guided Vehicle(AGV) and Double Stack Vehicle(DSV) at Automated Container Terminal(ACT). Usually, the main difference of AGV and DSV is capacity of container that they can transport between apron and yard block at once. AGV can carry out two 20 feet or one 40 feet maritime containers, but DSV can carry out four 20 feet or two 40 feet maritime containers. Therefore, DSV may improve more efficiency of stevedoring system of container terminal. In this paper, a simulation model using a graphics simulation system is developed to compare the proposed DSV with the current AGV at automated container terminal. The paper includes examples, performance tests and a discussion of simulation results.

• Journal of the Korean Society for Precision Engineering
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• v.1 no.3
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• pp.85-94
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• 1984

The WILDHABER-NOVIKOV gear, one of the circular arc gears, has the large contact area between the convex and concave profiled mating teeth, moves from one end of the tooth to the other axially making a face contact. Hence it provides a large load capacity than the Involute gear and still satisfying the law of gearing. In order to analyze the gear stress, a photoelastic investigation was carried out. Photo elastic model of the WILDHABER-NOVIKOV gears were made of Araldite CT200 in this investigation. For both the many teeth gear and the few teeth gear segments, External gears of all addendum type WILDHABER-NOVIKOV gear and the involute gear were tested. Included were the models with various profile raddi at the same pressure angle 20 .deg. and module 13.5. The flank stresses and fillet stresses of these gears were observed in each case and compared with those of gears. From this investigation, the following results were obtained. A. In the case of having many teeth gear: As the profile radius is increased, the fillet stresses of the WILDHABER-NOVIKOV gear become the same or less than that of the INVOLUTE gea, and the flank stress becomes smaller than that of the INVOLUTE gear. Therefore the better design condition is satisfied with a large profile radius. B. IN the case of having a few teeth gear: As the profile radius is increased the flank stress of WILDHABER-NOVIKOV gear becomes smaller than that of the INVOLUTE gear, but the fillet stresses become larger than that of the INVOLUTE gear. Therefore the larger design condition is satisfied with small profile radius.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.7
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• pp.665-671
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new automatic transmissions' gear. The gear noise was dramatically disappeared and the process and the results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.361-361
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• 2015

감세블록(baffle block)은 고속의 흐름에서 도수를 유도함으로써 과도한 에너지를 감세시키는 역할을 하는 구조물이며 구조물의 크기, 형태, 위치, 조합 등의 변수로 도수가 형성되는 조건을 조절하여 흐름에 영향을 줄 수 있다. 하단방류형 가동보에서 고속으로 방류되는 흐름의 Froude 수가 2.5에서 4.5 사이일 경우 발생하는 불규칙한 주기의 진동이 중첩 보강되면 감세하기 어려운 파동을 형성하여 수 Km 동안 지속될 수 있어 추가적인 조치가 필요하다(Peterka, 1984). 이 연구에서는 총 연장 11m, 폭 0.5m의 구형수로에 하단방류형 가동보와 감세블럭을 설치하여 감세블록의 위치가 에너지의 감세에 미치는 영향을 분석하고, 감세블록의 최적 위치를 제안하였다. 감세블럭은 높이 2cm, 폭 5cm의 구형단면으로 제작하여 일정한 간격으로 치형 배열하였으며, 가동보로 부터 5.5~8.5cm 지점에서 1cm간격으로 총 5가지 조건으로 수리실험을 수행하였다. 또한, 수문 하단에서의 Froude 수가 3.8~3.9를 만족하는 강한 도수가 발생할 수 있도록 유량을 조절 하였고, 유속과 수심은 3차원 유속계와 피에조미터를 이용하여 가동보로부터 0.2m간격으로 하류단 2m 지점까지 측정하였다. 실험 결과, 가동보로부터 도수가 발생하여 수위가 안정되는 지점까지의 도수길이는 감세블록을 설치한 경우, 설치하기 전의 1.1m와 비교하여 최소 27.3%에서 최대 81.8%만큼 짧아졌으며 감세블록 보에 가깝게 설치될수록 도수길이는 단축되는 것으로 나타났다. 가동보 하류부에서 도수가 발생한 이후 수심이 안정화되는 1m 지점에서, 도수 전후의 비에너지비로 정의되는 도수효율은 감세블록 미설치 시 74.9%이고, 감세블록이 설치된 조건에서는 54.9~60.6%로 감세블록에 의한 에너지 감소효과가 큰 것으로 나타났다. 에너지 감세 효과가 가장 큰 감세블록 위치는 가동보로부터 6.5cm 떨어진 곳으로 하류단 수심의 약 80%에 해당하는 지점이 감세블록의 최적 위치인 것으로 판단된다.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.475-482
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• 2019

This report is a case of 76-year old male patient who had difficulty in swallowing, pronunciation and suffered regurgitation of food. The patient lacks uvula and both tonsils, had short palatoglossal arch and soft palate, as well as defective left palatopharyngeal arch. The height and width of the soft palate defect were measured by reconstructing the Computed Tomography (CT) image in three dimensions. Phonation and soft palate obstructing ability were examined by nasometry and nasal endoscopy. Evaluations on phonetics and swallowing were done and improvements were shown. The patient was satisfied with the results of treatment.

• Fashion & Textile Research Journal
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• v.22 no.6
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• pp.834-843
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• 2020

This study develops 1/2 dress forms for draping. This study investigated the production status of domestic and foreign products in order to model their shape using CLO 3D. In addition, it developed torso-type and torso-crotch-type products that allowed for draping using a 3D printer. This study analyzed shape and size compared to developed ones after referring to the Size Korea 7th Survey data as well as seven domestic and foreign company websites. The results are follows. First, an investigation of the production status of the products for the size of most of the domestic ones (except K-4) indicated that the waist circumference was slimmer than Size Korea. Bust, waist, and hip circumferences ranged from 42.0 cm, 32.0 cm, and 45.0 cm - 49.0 cm, respectively, in Chinese products; 42.0 cm - 43.0 cm, 30.5 cm - 31.5 cm, and 46.0 cm - 46.5 cm in Japanese products; 43.0 cm, 35.0cm, and 46.5 cm in American products (Japanese body shape applied). Second, an avatar was produced on a 3D software with the average size of 20-24year-old women, and its file modified as a dress form for 3D printing with PLA filament to produce dress forms for draping, workable with pins, using quilting cotton and cotton cloth. Third, the comparisons of the form and flattening between the developed dress forms and the selling ones indicated that flattening was bigger in the waist part of the former than the latter. The waist is produced too slim in the existing dress forms; therefore, it is necessary to correct the waist circumference. Unlike existing dress forms, the developed ones were produced in proximity to the average size of 20-24 year-old women in the Size Korea 7th Survey.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.9-13
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• 2022

Electric wheelchairs, the output from the motor is mainly applied to a speed reducer using a power transmission device such as a belt or a chain. However, although a speed reducer using a belt or chain is a simple device, it occupies a lot of space and has a space limitation, so it is not suitable for an electric wheelchair driving part. However, since the speed reducer of the planetary gear type is decelerated on the same axis, the volume can be reduced, so the space constraint is less than that of the belt or chain type reducer. Therefore, in this study, a driving part that can obtain great propulsion with a speed reducer using a planetary gear type was developed through a study on the driving part of a wheelchair that can be switched between manual and electric. Accordingly, the tooth shape of the planetary gear applied to the reducer was designed using the Kisssoft program. In addition, the drive part was designed to be applicable to the existing wheelchair wheels, and the mechanism was optimized for the manual/electric switching principle and operation principle of the drive part. Based on the research contents, the final design and manufacture of the wheelchair reducer drive unit in the form of a planetary gear having one sun gear, two planetary gears and one ring gear was carried out.