• 한국지반공학회논문집
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• 제40권3호
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• pp.101-108
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• 2024

터널 공사중 발생 가능한 쐐기블록(Key block)을 막장관찰 중 인지하여 전방으로 형성되는 쐐기블록을 예상하고, 안전율을 확인할 수 있는 시스템을 개발하였다. 막장관찰시, 레이저 스캐너를 이용하여 암반면의 3차원 점군을 수집하고, 이를 근거로 굴착면을 형상화한 후, 암반 절리면을 도출한다. 절리면은 주향과 경사각을 가지고 있으므로, 절리면들의 조합을 통해 형성되는 쐐기블록을 반복 계산을 통해 도출하고, 각 쐐기블록의 안전율을 계산한다. 모형실험을 통해 시스템의 절리면 특성 산출의 정확성을 확인하였고, 절리면 정보를 입력하여 계산되는 기존 상용 소프트웨어의 결과값과 비교하여 개발 프로그램이 오차 1%이내로 계산 결과를 얻을 수 있음을 확인하였다.

• 대한물리의학회지
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• 제11권1호
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• pp.23-34
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• 2016

PURPOSE: This study aimed to assess the relationship between the severity of radiographic features and pain and function in patients with knee osteoarthritis (KOA). METHODS: Seventy-eight subjects (14 men, 64 women) with KOA, between the ages of 41 and 83 years (mean age, 61.29 years), were included. All the subjects diagnosed with KOA were scored for severity of radiographic KOA according to the Kellgren-Lawrence (K/L) grade, visual analogue scale (VAS), knee joint range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), maximum muscle power (MMP), and sit-to-stand (STS) and one-leg standing (OLS) tests. Associations among the K/L grade, diagnosis, pain, and function were examined by correlation analysis. RESULTS: There were no significant differences between the K/L grade, and the VAS, STS test time, and WOMAC scores (p>.05). There were no significant differences between the K/L grade, bilateral ROM, MMP, and left OLS test time (p>.05). However, there was a significant difference between the K/L grade and right OLS test time (p<.05). The K/L grade was negatively correlated with the left OLS test time(r=-.24, p<.05) and with the right OLS test time (r=-.307, p<.01). CONCLUSION: These results suggest that radiographic KOA was not associated with pain, knee MMP, ROM, and STS test time, but had a weak negative correlation with OLS test time.

• 대한기계학회논문집A
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• 제41권9호
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• pp.809-815
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• 2017

압력용기 재료로 사용되는 STS 304강은 저온에서 기계적 특성이 우수하지만, 다른 합금과 비교하여 중량이 무겁다. 이러한 문제를 해결하는 방안으로 STS 304강에 콜드 스트레칭(Cold stretching)공법을 사용하는 방법이 있다. 본 연구에서는 ASME 규정에 따라 제작된 콜드 스트레칭 압력용기에서 직접 채취한 콜드 스트레칭부 및 용접부 시험편을 이용하여, 상온 및 $-170^{\circ}C$에서 응력비 0.1과 0.5에 대하여 컴플라이언스법을 이용하여 피로균열진전시험을 수행하였다. 시험결과, 용접부의 피로균열진전속도는 콜드 스트레칭부에 비해 동일 응력확대계수범위에서 빠른 것을 확인하였다. 이러한 결과는 콜드스트레칭 공법을 사용하여 제작한 STS강 압력용기 개발을 위한 기초자료로 활용될 수 있을 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1679-1683
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• 2007

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. For fatigue design of gas welded joints such as fillet and plug and ring type joint, it is important to obtain optimum design parameter information on gas welded joints. In this paper, analysis approach for fatigue test using experimental design are evaluated optimum factor in gas welded joint type and geometrical parameters of materials. Using these results, that factors applied to fundamental information for fatigue design.

• 한국가구학회지
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• 제17권2호
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• pp.25-34
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• 2006

This experiment was carried out to investigate the high-frequency gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on MDF edge-glued boards. The edge-glued boards were glued lengthwise with butt, scarf, or finger joint. The wastes of MDF boards were reused as board materials. The obtained results are summarized as follows; the bending strength of edge-glued MDF increased slightly with the HF heating time, but the economically desirable heating time was 6 minutes. The bending and tensile strength of edge-glued MDF were high with scarf, finger and butt joint, in order. The strength of finger jointed MDF showed 80% of scarf jointed MDF. The effects of location of finger joints on the bending strength of edge-glued MDF were larger than those of the numbers of finger joints. The bending strength of edge-glued MDF with one joint on the middle position showed 40% decrease in comparison with non-jointed MDF.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.89-94
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• 1994

This paper presents an impact control algorithm for reducing the potentially damaging effects by interation of redundant manipulators with their environments. In the. proposed control algorithm, the redundancy is resolved at the torque level by locally minimizing joint torque, subject to tire operational space dynamic formulation which maps tire joint torque set into the operational forces. For a given pre-impact velocity of the manipulator, the proposed approach is on generating joint space trajectories throughout the motion near the contact which instantaneously minimize the impulsive force which is a scalar function of manipulator's configurations. This is done by using the null space dynamics which does not affect the motion of an end-effector. The comparative evaluation of the proposed algorithm with a local torque optimization algorithm without reducing impact is performed by computer simulation. The simulation results illustrate the effectiveness of the algorithm in reducing both the effects of impact and large torque requirements.

• 환경영향평가
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• 제5권1호
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• pp.95-105
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• 1996

Meteorological Joint Frequency Function required indispensably in long-term air quality prediction models were discussed for practical application in Korea. The algorithm, proposed by Turner(l964), is processed with daily solar insolation and cloudiness and height basically using Pasquill's atmospheric stability classification method. In spite of its necessity and applicability, the computer program, called STAR(STability ARray), had some significant difficulties caused from the difference in meteorological data format between that of original U.S. version and Korean's. To cope with the problems, revised STAR program for Korean users were composed of followings; applicability in any site of Korea with regard to local solar angle modification; feasibility with both of data which observed by two classes of weather service centers; and examination on output format associated with prediction models which should be used.

• 공학교육연구
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• 제22권5호
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• pp.3-12
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• 2019

Due to the expansion of rolling admissions and diversification of college admissions, the widening gap between the level of scholastic ability and academic performance is the reality of college education. Thus, based on the incoming class of College A, this study analyzes the correlation between incoming students who enrolled in a college mathematics course during their first semester. Through this analysis, this study searches for a way to efficiently instruct students from various learning backgrounds when enrolled in the same course. Also, this study searches for a solution to lower the deviation of college mathematics' academic performance among engineering majors by examining the efficiency of a joint managed college mathematics curriculum.

• 치과방사선
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• 제19권1호
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• pp.105-121
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• 1989

The author analysed tomograms and submento-vertex radiograms of 90 temporomandibular joints from 45 asymptomatic young adults. 15 had Angle class Ⅰ malocclusion, 15 classⅡ and 15 class Ⅲ. Corrected lateral tomograms were obtained in three condylar positions; centric occlusion, centric relation and 1 inch mouth opening. The condylar angulation, depth of cut, joint spaces were analysed in each radiogram. The obtained results were as follows; 1. The mean condylar angulation in Angle class Ⅰ, Ⅱ, Ⅲ group was 17.55±5.51° 13.33±8.85° 16.25±6.60° respectively, and there was no significant difference in each group. The mean condylar angulation of right side (16.62±7.23°) was larger than left side (14.80±7.33°). 2. The mean depth of cut in Angle class Ⅰ, Ⅱ, Ⅲ group was 8.13±1.61㎝, 3.05±3.80㎝, 7.75±2.19㎝, respectively. Angle class Ⅰ and class Ⅱ group revealed significant difference in measurement (p<0.0l). 3. The mean height of articular fossa in Angle class Ⅰ, Ⅱ, Ⅲ group was 8.67±3.06㎜, 9.61±2.57㎜, 8.93±2.83㎜, respectively. And the mean width of articular fossa was 19.90±2.80㎜, 19.48±3.83㎜, 20.36±4.82㎜, respectively. 4. The mean height and width of condylar head was 5.11±1.16㎜, 11.20±2.26㎜, respectively. 5. In centric occlusion, the superior joint space was the largest (3.42±1.42㎜), followed by anterior joint space (2.94±1.95㎜) and the posterior joint space (2.64±1.19㎜. In centric relation, the anterior joint space was the largest (3.86±2.17㎜), followed by the superior joint space (3.64±3.68㎜) and the posterior joint space (1.18±0.77㎜). 6. The displaced measurement from centric relation to centric occlusion was 1.10±1.04㎜ anteriorly and 0.24±0.97㎜ inferiorly. In 1 inch mouth opening state, the condylar head displaced posteroinferiorly (2.49±2.49㎜ posteriorly, 1.17±1.34㎜ inferiorly) from the apex of articular eminence. And Angle class Ⅰ and Ⅱ group, Angle class Ⅱ and Ⅲ group revealed significant difference in posterior measurement, respectively (p<0.01).

• Archives of Reconstructive Microsurgery
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• 제14권1호
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• pp.63-69
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• 2005

Purpose: The purpose of this study was to analyze the clinical results after Steindler flexoplasty. Materials and Methods: We analyzed 6 cases who had nearly normal finger and wrist joint flexion function, but could not flex elbow joint actively because of upper arm type brachial plexus injury. We performed operation during the period from February 1997 to July 2003. There were 5 males and 1 female with mean age of 28 years (range: $19{\sim}51$ years) when Steindler flexoplasty was done. The average follow-up period was 3 years 11 months (range: 12 months${\sim}$7 years 4 months). We assessed active range of motion of elbow joint, muscle power and elbow function by Mayer & Green grade scale at last follow-up. We assessed how much they were favorable for Steindler flexoplasty and had improvement of upper extremity function and correction of deformity. Results: Postoperative, flexion range of elbow joint improved to average $111.7^{\circ}$ (range: $90{\sim}130^{\circ}$). $25.8^{\circ}$ (range: $15{\sim}45^{\circ}$) in flexion contracture and $16.6^{\circ}$ (range: $10{\sim}35^{\circ}$) in pronation contracture were remained. Range of motion of elbow joint improved to average $85.3^{\circ}$ (range: $45{\sim}105^{\circ}$). Flexion power of elbow joint improved to Grade 5 in all cases. Postoperatively on Mayer & Green grade scale, there were excellent in 3 cases(50%), good in 2 cases(33.3%), fair in 1 case(16.7%). On patient's own assessment of functional improvement, there were excellent in 4 cases(66.6%), good in 1 case(16.7%) and fair in 1 case(l6.7%). Conclusion: Steindler flexoplasty can reserve good clinical results with being improved to active flexion of elbow joint in cases who have functional hand and wrist, but paralysis upper arm muscle in brachial plexus injury.