• 대한기계학회논문집A
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• 제35권7호
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• pp.785-790
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• 2011

본 연구에서는 인체의 하지부를 다물체 시스템으로 모델링하여 무릎관절에 걸리는 구속력의 불확실성을 추정하였다. 일반적으로 근육의 기계적인 특성은 Hill-type muscle model 이 사용되며 여기에 적용되는 인체의 특성과 해부학적인 데이터는 지난 십 수년 동안 크게 발전되었다. 그러나 정확하게 그것들을 안다는 것은 불가능하며 개인마다 다른점을 고려해야 할 필요가 있다. 본 논문에서는 Hill-type muscle model 과 함께 인체의 해부학적인 데이터를 통계 방법론을 이용하여 무릎 관절에 걸리는 구속력의 불확실성을 추정하였다. 초기 앉아있는 자세에서 일어서는 과정에서 작용하는 구속력을 추정하였으며 이때 인체 하지 근육의 특성을 musculoskeleton-actuator 를 이용하여 해석하였다.

• 한국의류학회지
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• 제30권5호
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• pp.722-732
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• 2006

The pattern making of the tight-fitting collars which often used in diving suits, dance wear, or cycle wear has not been fully established. To develop tight-fitting collar pattern directly from 3D images from the representative somatotypes, dressforms developed by Jaeun Jung were used. The 3D scan data of the four male dressforms were obtained using Exyma-1200. Triangle Simplification and the Runge-Kutta method were applied to reduce the 3D scan data points and to make the segmented triangular patches in a plane from 3D data. As results, apparent differences between the tight-fitting collar patterns obtained from the 3D scan data and the ordinary 2D collar patterns were found around the center back line. The curvatures of the center back line were higher in all types of the tight-fitting collar than in the ordinary collar pattern. Relative differences in the shape of collar lines among four representative Korean men were reported. To fit the curved shape of the back neckline, 1.8 cm should be reduced from the upper neckline in average. We suggested the direct pattern making method for the 2D tight-fitting collar patterns considering the 3D shape of various types of men's dressform.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.261-266
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• 2013

Purpose: This study was performed to investigate the bone thickness of the infrazygomatic crest area by computed tomography (CT) for placement of a miniplate as skeletal anchorage for maxillary protraction in skeletal Class III children. Materials and Methods: CT images of skeletal Class III children (7 boys, 9 girls, mean age: 11.4 years) were taken parallel to the Frankfurt horizontal plane. The bone thickness of the infrazygomatic crest area was measured at 35 locations on the right and left sides, perpendicular to the bone surface. Results: The bone was thickest (5.0 mm) in the upper zygomatic bone and thinnest (1.1 mm) in the anterior wall of the maxillary sinus. Generally, there was a tendency for the bone to be thicker at the superior and lateral area of the zygomatic process of the maxilla. There was no clinically significant difference in bone thickness between the right and left sides; however, it was thicker in male than in female subjects. Conclusion: In the infrazygomatic crest area, the superior and lateral area of the zygomatic process of the maxilla had the most appropriate thickness for placement of a miniplate in growing skeletal Class III children with a retruded maxilla.

• 구강회복응용과학지
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• 제30권4호
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• pp.329-338
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• 2014

치주질환이나 우식으로 인해 구치부 치아가 상실된 환자들은 잔존하고 있는 전치부 및 소구치부 치아로 안정된 교합고경을 유지하기 어렵다. 구치의 상실로 대합치의 정출이나 인접치의 경사가 발생되는 경우 교합평면이 붕괴되거나 부적절한 교합간섭을 야기하게 된다. 만약 치아 상실 상태가 지속된 경우에는 하악의 전방이동으로 인해 상악 전치의 동요와 순측 이개를 초래하게 되며 치주질환이 동반된 경우에는 더욱 심각한 상황으로 변화한다. 이와 같이 치아의 병적 이동이 일어난 환자의 치료는 보존 및 치주치료, 교정 치료를 통한 재배열, 그리고 상실된 치아의 보철수복을 통한 교합 고경의 재설정 및 유지와 같은 다과간 협력 진료가 매우 중요하다.

• 한국전자파학회논문지
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• 제15권6호
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• pp.554-559
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• 2004

본 논문에서 새로운 구조의 2단 대역통과 여파기 구조를 제시하였다. 제시된 구조는 마이크로스트립 헤어핀선로와 그 아래의 접지면에 슬롯선로를 구현한 형태이다. 각 공진기 선로가 유전체의 양면에 위치하여 여파기의 크기를 크게 줄일 수 있고 감쇄극을 통과대역 양쪽에 적절하게 위치시키어 저지대역 특성을 개선시킬 수 있다. 설계 및 제작된 여파기는 중심주파수(1.9 ㎓)에서 69 MHz치 대역폭을 나타내었다. 구현된 여파기는 일반적인 λ/4결합선로 여파기에 비해 33 %정도의 크기를 가지며, 통과대역밖의 양쪽에 감쇄극을 위치시키어 여파기의 차단특성을 개선하였다. 부가적으로 일반적인 결합선로 여파기의 경우 동일사양의 여파기 구현시 입출력 결합선로의 경우 0.1 mm의 간격이 필요하나, 제시된 구조는 0.3 mm로 세 배 더 넓은 간격으로 구현이 가능하여 소형, 협대역 여파기 구현에 적합한 구조이다.

• 국제초고층학회논문집
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• 제9권1호
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• pp.71-79
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• 2020

As the workplace evolves in our vertical cities, the need for "think spaces" and the public realm to meet, create and innovate will become integral to tall buildings. These people places are designed to address the social challenges and enhance the co-working environments which are emerging in the dense urban context of our future cities. The design of sky terraces and the "spaces between" offer a greener, more humane and smarter work environment for the future. The public realm should no longer be held down, fixed to the ground plane, but rather become part and parcel of the upper levels of our workplace centers. These collective spaces in our workplace centers must provide a three dimensional matrix of connected and identifiable platforms to leverage the open and progressive future way of working. This will enable social networking and idea sharing, and create multi-dimensional, multi-level business incubators for innovation and creativity. The BCO ( British Council of Offices) has performed a landmark Wellness Matters Report which provides an exemplary roadmap for the future of the workplace. Our future vertical cities must also provide for serendipity in the workplace; a key attribute to drive the information exchange and collaboration that are proven to provide positive and progressive business outcomes. In addition to demonstrating examples of existing built work and the concept of the integrated vertical public realm, the presentation also will consider and define wellness in the workplace as a critical factor in our design strategies and our future workplace environments Hanging Gardens, Roof Terraces and the Vertical Plazas; designed for interchange, wellness, animation and collaboration.

• 한국재료학회지
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• 제5권5호
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• pp.598-605
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• 1995

Thin films of $YB_{2}Cu_{3}O_{7-d}$ were prepared on various substrated of MgO(100), $SrTiO_{3}$, and $LaAlO_{3}$ by using off-axis magentron sputtering methods and annealing in-situ. The prarameters of film fabrication processes had been optimized through a "follow the lcoal maxima" strategy to yield good quality films in therms of the critical temperature $T_{c}$ and the critical current density $J_{c}$. Optimizedproecsses employing a plane magndtron and an cylindrical magnetron yielded $T_{c}$>90K along with $J_{c}$$10^{6}$A/$\textrm{cm}^2$ at 77K and > 2${\times}$$10^{7}$A/$\textrm{cm}^2$ at 5K. The sampels, however, showed degradationinthe properties, after chemical etching for fabrication of microbridges with the line width of 2-10 mocrons. In particular, the value of $T_{c}$ for the microbridges of 2microns was as small as 80%. The degradation was strongly dependent on the line width through a formula : $T_{c}$(e)=$T_{c}$)b) [1-a exp(-1000 bL)} where $T_{c}$(e) and $T_{c}$ (b) are the values of $T_{c}$ in the absolute scale measured after and before chemical etching, respectively and L is the line width in mm. By utilizing a best fitting technique, the proper constant values of a and to b were found as exp(-1.2) and 0.22, respectively. This formula was very useful in estimatiing the upper limit of the device operationtemperature.

• 한국농공학회지
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• 제39권3호
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• pp.72-82
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• 1997

In all inelastic deformations time rate effects are always present to some degree. Whether or not their exclusion has a significant influence on the prediction of the material behaviour depends upon several factors. In the study of structural components under static loading conditions at normal temperature it is accepted that time rate effects are generally not important. However metals, especially under high temperatures, exhibit simultaneously the phenomena of creep and viscoplasticity. In this study, elastoplastic and elasto-viscoplastic models include nonlinear geometrical effects were developed and several numerical examples are also included to verify the computer programming work developed here in this work. Comparisons of the calculated results, for the elasto-viscoplastic analysis of an internally pressurised thick cylinder under plane strain condition, have shown that the model yields excellent results. The results obtained from the numerical examples for an elasto-viscoplastic analysis of the Nuclear Reinforced Concrete Containment Structure(NRCCS) subjected to an incrementally applied internal pressure were summarized as follows : 1. The steady state hoop stress distribution along the shell layer of dome and dome wall junction part of NRCCS were linearly behave and the stress in interior surfaces was larger than that in exterior. 2.However in the upper part of the wall of NRCCS the steady state hoop stress in creased linearly from its inner to outer surfaces, being the exact reverse to the previous case of dome/dome-wall junction part. 3.At the lower part of wall of NRCCS, the linear change of steady state hoop stress along its wall layer began to disturb above a certain level of load increase.

• 대한치과교정학회지
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• 제50권3호
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• pp.216-226
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• 2020

Root resorption can be caused by several factors, including contact with the cortical bone. Here we report a case involving a 21-year-old female with Angle Class II, division 1 malocclusion who exhibited significant root resorption in the maxillary right central incisor after orthodontic treatment. The patient presented with significant left-sided deviation of the maxillary incisors due to lingual dislocation of the left lateral incisor and a Class II molar relationship. Cephalometric analysis demonstrated a Class I skeletal relationship (A point-nasion-B point, 2.5°) and proclined maxillary anterior teeth (upper incisor to sella-nasion plane angle, 113.4°). The primary treatment objectives were the achievement of stable occlusion with midline agreement between the maxillary and mandibular dentitions and appropriate maxillary anterior tooth axes and molar relationship. A panoramic radiograph obtained after active treatment showed significant root resorption in the maxillary right central incisor; therefore, we performed cone-beam computed tomography, which confirmed root resorption along the cortical bone around the incisive canal. The findings from this case, where different degrees of root resorption were observed despite comparable degrees of orthodontic movement in the bilateral maxillary central incisors, suggest that the incisive canal could be an inducing factor for root resorption. However, further investigation is necessary to confirm this assumption.

• Structural Engineering and Mechanics
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• 제44권6호
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• pp.775-799
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• 2012

This work approaches the structural performance of masonry arches that have a small ratio between number of vossoirs and span length. The aim of this research is to compare and validate three different methods of analysis (funicular limit analysis F.L.A., kinematic limit analysis K.L.A. and plane stress Finite Element Analysis F.E.A.) with an experimental campaign. 18 failure tests with arches of different shapes and boundary conditions have been performed. The basic failure mechanism was the formation of enough hinges in the geometry. Nevertheless, in few cases, sliding between vossoirs also played a relevant influence. Moreover, few arches didn't reach the collapse. The FLA and KLA didn't find a solution close to the experimental values for some of the tests. The low number of vossoirs and joints become a drawback for an agreement between kinematic mechanism, equilibrium of forces and geometry constraints. FLA finds a lower bound whereas KLA finds an upper bound of the ultimate load of the arch. FEA is the most reliable and robust method and it can reproduce most of the mechanism and ultimate loads. However, special care is required in the definition of boundary conditions for FEA analysis. Scientific justification of the more suitability of numerical methods in front of classic methods at calculating arches with a few vossoirs is the main original contribution of the paper.