• 한국기계가공학회지
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• 제19권9호
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• pp.107-115
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• 2020

The rotation accuracy of the main spindle that determines the accuracy of CNC machine tools is closely related to the quality of production because it directly affects the shape error and surface roughness of the workpiece. Therefore, the main spindle requires high rotation accuracy, rigidity, and rotation technology. This rotation accuracy is greatly affected by the bearing, center alignment between rotating parts, assembly tolerance, and unbalance of the rotation mass. In this study, the effects of the unbalance of the rotation mass of the main spindle on the rotation accuracy were investigated experimentally. In particular, we tried to study the technical reasons for improving the unbalance of the main spindle and maintaining the rotation accuracy as we verified the correlation between the vibration characteristics of CNC machine tools due to the specifically set unbalance amount and the surface roughness of the workpiece.

• 한국측량학회지
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• 제24권3호
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• pp.251-259
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• 2006

기존 철도의 전철화 사업 수행을 위해서는 노후 터널의 역학적 안정성 조사와 함께 건축한계의 확보가 필수적으로 이루어져야 한다. 건축한계가 확보되지 않으면 터널의 선형 개선을 토대로 한 재시공이 발생하므로 측량 자료가 요구된다. 본 연구에서는 영동선 구간의 3개 터널에 대하여 동일좌표체계의 정밀 측량을 실시하고 종횡단면도, 종단레일고, 레일경사, 횡단터널높이, 건축한계높이 등의 자료를 취득하여 직선 및 곡선 터널구간의 건축한계를 효율적으로 분석하였다. 종횡단 측량성과를 이용한 도면과 기존 설계값과 비교하여 건축한계를 분석하고 시공성을 파악할 수 있도록 전철화 설계의 안정성에 대한 평가자료로 제시할 수 있었으며, 향후에는 터널구조물의 실시간 모니터링 시스템 개발에 이의 운용성을 증대시키고자 한다.

• Archives of Plastic Surgery
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• 제42권2호
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• pp.179-185
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• 2015

Background Capsular contracture is the most troublesome complication in breast implant surgery. Although capsule formation can be seen as a normal reaction to a foreign body, it can induce pain, hardness, deformity, and other pathologic problems. Surgical intervention is required in severe cases, but even surgery cannot guarantee a successful outcome without recurrence. This experimental study confirms that single topical administration of leukotriene antagonist zafirlukast (Accolate, Astrazeneca) reduces peri-implant capsule formation and prevents capsular contracture. Methods Twelve smooth-surfaced cohesive gel implants were implanted in New Zealand White rabbits. These miniature implants were designed to be identical to currently used products for breast augmentation. The rabbits were divided into 2 groups. In the experimental group (n=6), the implant and normal saline with zafirlukast were inserted in the submuscular pocket. In the control group (n=6), the implant and normal saline alone were used. Two months later, the implants with peri-implant capsule were excised. We evaluated capsule thickness and collagen pattern and performed immunohistochemical staining of myofibroblasts, transforming growth factor $(TGF)-{\beta}1$, 2. Results The thickness of the capsules in the experimental group was reduced in both dorsal and ventral directions. The collagen pattern showed parallel alignment with low density, and the number of myofibroblasts as well as the amounts of $TGF-{\beta}1$ and $TGF-{\beta}2$ were reduced in the experimental group. Conclusions We suggest that single topical administration of leukotriene antagonist zafirlukast can be helpful in reducing capsule formation and preventing capsular contracture via myofibroblast suppression, modulation of fibroblastic cytokines, and anti-inflammatory effect.

• Journal of Korean Neurosurgical Society
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• 제40권6호
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• pp.412-418
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• 2006

Objective : The safety of titanium metal cages in tuberculous spondylitis has not been investigated. We evaluated the outcome and complications of titanium mesh cages for reconstruction after thoracolumbar vertebrectomy in the tuberculous spondylitis. Methods : There were 17 patients with 18 operations on the tuberculous spondylitis in this study. Sixteen patients were operated with anterior corpectomy and reconstruction with titanium mesh cage followed by posterior transpedicular screw fixations on same day, two pateints were operated by either anterior or posterior approach only. After the affected vertebral body resection and pus drainage from the psoas muscle, titanium mesh cage, filled with morselized autogenous bone, was inserted. All the patients had antituberculosis medication for 18 months. The degree of kyphosis correction and the subsidence of cage were measured in the 15 patients available at a minimum of 2 years. Outcome was assessed with various cross-sectional outcome measures. Recurrent infection was identified by serial ESR[Erythrocyte Sedimentation Rate] and CRP[Cross Reactive Protein]. Results : There was no complication from the use of a titanium mesh cage. Recurrent infection was not detected in any case. Average preoperative of $9.2^{\circ}$ was reduced to $-2^{\circ}$ at immediate postoperative period, and on final follow up period kyphotic angle was measured to be $4.5^{\circ}$. Postoperatively, subsidence was detected in most patients especially at ambulation period, however further subsidence was prevented by the titanium mesh cage. Osseous union was identified in all cases at the final follow-up. Conclusion : The cylindrical mesh cage is a successful instrument in restoring and maintaining sagittal plane alignment without infection recurrence after vertebrectomy for tuberculous spondylitis.

• 응용통계연구
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• 제27권4호
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• pp.577-588
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• 2014

자료의 수집과 저장이 수월해 지면서 대용량의 자료들이 존재하고 특히 개체 보다 변수가 더 많은 자료들이 생산되고 있다. 변수들이 증가하면서 다중공선성 같은 문제들이 발생하여 분석의 어려움에 봉착하게 된다. 이러한 문제를 해결하는 방법들이 많이 연구되었지만 다소간의 정보의 손실을 감내하고 연속형 자료를 범주형 자료로 변환하면 나름 유용한 분석이 가능하다고 본다. 대용량 범주형 자료의 대표적인 사례로 유전자 염기 서열 자료가 있고 이를 분석하기 위한 많은 기술들이 발달되어 있다. 본 논문에서는 국내 은행들이 생산해 낸 다양한 지표들을 분석하기 위해 유전자 염기 서열 분석 기법을 적용하여 분석하였고 나름 유용한 정보를 얻을 수 있음을 보였다. 본 논문에서 사용한 자료는 11개의 은행과 5개의 저축은행과 관련된 78개 재정 지표를 갖는 자료로서 심각한 다중 공선성이 존재하여 자료를 범주화하고 분석한 결과 몇 가지 유용한 결과를 도출하였다.

• 한국항공우주학회지
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• 제46권7호
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• pp.583-591
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• 2018

본 논문에서는 하나의 큰 태양전지판 전개시험을 위해 새로운 전개시험장치를 제안하였다. 지상에서 전개시험을 수행하기 위해서는 궤도에서와 유사한 무중력 환경을 만들기 위해 중력 보상을 고려한 장치를 사용해야 한다. 기존에 주로 사용되는 전개시험장치를 시험하고자 하는 태양전지판 전개에 적용 가능한지 판단하기 위해 간단한 개념설계, 해석 그리고 시험 등을 통해 장단점을 분석하였다. 지상 시험의 문제점인 공기저항 문제를 해결하기 위해 더미 프레임을 제안하였으며 중력축과의 정렬 문제를 해결하기 위해 전개 장치에 자동조심 베어링 및 조절나사를 적용하였다. 그리고 테잎 스프링 힌지축의 변화를 보상하기 위해 반지름 방향 이동을 위한 수평 이동 베어링이 적용되었다. 이로부터 본 논문에서 전개하고자 하는 태양전지판에 특성화된 새로운 전개시험장치를 개발하고 검증함으로써 기존 전개시험장치의 문제점을 해결하였다.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.598-609
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• 2017

Pediococcus pentosaceus ID-7 was isolated from kimchi, a Korean fermented food, and it showed high activity for lactose hydrolysis. The ${\beta}$-galactosidase of P. pentosaceus ID-7 belongs to the GH2 group, which is composed of two distinct proteins. The heterodimeric LacLM type of ${\beta}$-galactosidase found in P. pentosaceus ID-7 consists of two genes partially overlapped, lacL and lacM encoding LacL (72.2 kDa) and LacM (35.4 kDa). In this study, Escherichia coli MM294 was used for the production of LacL, LacM, and LacLM. These three types of recombinant proteins were expressed, purified, and characterized. The specific activities of LacLM and LacL were 339 and 31 U/mg, respectively. However, activity was not detected with LacM alone. The optimal pH of LacLM and LacL was pH 7.5 and pH 7.0, and the optimal temperature of LacLM and LacL was $40^{\circ}C$ and $50^{\circ}C$, respectively. The optimal temperature changes indicate that LacLM is able to achieve higher activity at a relatively lower temperature. LacLM was strongly activated by $Mg^{2+}$, $Mn^{2+}$, and $Zn^{2+}$, which was not true for LacL. Consistent with this, EDTA strongly inactivated LacLM and LacL, but the presence of reducing agents did not dramatically alter the activity. Taken together, multiple alignment of amino acid sequences and phylogenetic analysis results of LacL and LacM of P. pentosaceus ID-7 suggest the evolution of LacL into LacLM and that the use of divalent metal ions results in higher activity.

• Journal of Astronomy and Space Sciences
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• 제31권2호
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• pp.177-186
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

• 한국정보통신학회논문지
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• 제19권5호
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• pp.1213-1220
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• 2015

최근 전자칠판 시스템, 스마트 기기의 보급과 더불어 다양한 디지털 콘텐츠가 등장하면서 종이 교과서를 활용하는 전통적인 교육에서 위 기기들을 활용하는 스마트 교육으로 진입하기 위한 작업이 정부 주도하에 진행 중에 있다. 스마트 교육을 활성화하기 위해서는 실제 현장의 강사들이 스마트 교육 인프라를 쉽게 활용할 수 있어야 한다. 특히, 전자칠판은 현장의 강사들이 가장 많이 활용할 것으로 예상되는 기기로 이 기기에서 동작하는 판서 소프트웨어는 복잡하지 않은 인터페이스를 제공하고 사용 방법이 간단해야 한다. 본 논문에서는 누구나 쉽게 활용할 수 있는 전자칠판용 판서 소프트웨어를 개발하였다. 개발된 판서 소프트웨어는 기본 판서 기능이외에 사용자의 제스처를 인식하여 그에 대응하는 기능을 수행하는 제스처 인식 기능과 판서 위치에 따른 동적 메뉴 배치 기능, 그리고 사용 빈도 기반의 자동 버튼 정렬 기능을 제공한다.

• 대한정형도수물리치료학회지
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• 제22권1호
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• pp.51-58
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• 2016

Background: Evidence for effective management of scapular downward rotation syndrome is limited. The present study was performed to compare the scapular muscle activation through 4weeks wall slide exercise and sling slide exercise in subjects with scapular downward rotation syndrome. Methods: Twenty-two subjects with scapular downward rotation syndrome participated in the study. Surface electromyography data were collected from the upper and lower trapezius, serratus anterior and pectoralis major during shoulder flexion of $60^{\circ}$, $90^{\circ}$ and $120^{\circ}$ in the sagittal plane. The alignment of the scapula was measured using radiographic analysis. Subjects were assessed pre and post a 4 weeks exercise (wall slide, sling slide). The significance of the difference in pre- and post-exercise within each groups was assessed using a paired t-test. The significant difference between wall- and sling-exercise was used a independent t-test. Results: In the wall slide group, the muscle activity of upper trapezius decreased significantly during shoulder flexion at $60^{\circ}$, $90^{\circ}$ and $120^{\circ}$ after 4 weeks, and the muscle activity of serratus anterior increased significantly at all angles. Also, the muscle activity of pectoralis major decreased significantly at $90^{\circ}$ and $120^{\circ}$. Conclusions: Based on such results, it can be said that wall slide exercise is effective than sling slide exercise for the subjects with scapular downward rotation syndrome.