• Imaging Science in Dentistry
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• 제42권4호
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• pp.243-247
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• 2012

Purpose: This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Materials and Methods: Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. Results: There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm ($IC_{95%}$:6.04-6.54) and 6.79 mm ($IC_{95%}$:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64mm($IC_{95%}$:6.40-6.89) and 6.79mm($IC_{95%}$:6.45-7.11), respectively. Conclusion: The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

• 대한기계학회논문집B
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• 제34권3호
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• pp.309-316
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• 2010

본 연구에서는 입자의 크기 및 3차원 속도를 측정할 수 있는 디지털 업자 홀로그래피 시스템을 개발하고, 개발된 시스템의 효용성을 검증하기 위하여 층류 채널 유동장에 적용하여 보았다. 디지털 홀로그램을 기록할 수 있는 이중 펄스 홀로그래피 시스템을 구축하였고, 상관계수법을 이용한 초점면 결정, Wiener 필터를 사용한 잡음 제거, 두 개의 이진화값 및 분할 이진화방법 등을 사용하여 기록된 홀로그램 및 재생이미지를 처리하였으며, 동일 입자의 추적은 입자가 액적처럼 큰 경우는 일치확률법을, 유동장의 추적 입자처럼 작은 경우는 상호상관법을 사용하였다. 개발된 시스템을 사용하여 층류 채널 유동의 축방향 속도를 측정하였으며, 이론적 예측식과 비교하여, 디지털 입자 홀로그래피 시스템의 유용성을 확인하였다.

• 한국철도학회논문집
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• 제16권2호
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• pp.110-116
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• 2013

궤도틀림은 철도차량의 주행안전성 및 승차감에 매우 큰 영향을 미치는 중요 인자 중 하나이다. 따라서, 차량의 주행안전성과 승차감의 확보를 위해서는 주행속도, 차량의 동적특성, 궤도틀림 검측차의 검측특성, 검측주기등을 고려하여 적정한 궤도틀림 기준을 설정하고, 관련 기준에 따라 궤도틀림을 철저히 관리하여야 한다. 본 논문에서는 궤도틀림 중에서 방향틀림이 KTX 차량의 거동에 미치는 영향을 조사하기 위하여 철도차량 동특성 해석프로그램인 VAMPIRE를 이용하여 방향틀림의 파장과 진폭에 대한 매개변수해석을 수행하였다. 방향틀림 크기와 파장에 따른 KTX의 탈선계수, 대차가속도, 차체가속도 및 궤도횡압 등의 주행거동을 조사하였으며, 방향틀림이 KTX차량의 주행안전성과 승차감에 미치는 영향을 분석하였다. 방향틀림은 차량주행안전성에 미치는 영향이 크며, KTX 주행안전성 확보를 위하여 방향틀림을 엄격하게 관리하여야 함을 알 수 있었다.

• 대한인간공학회지
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• 제27권3호
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• pp.71-79
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• 2008

Walking shoes for walking and jogging have been used to enjoy lots of leisure time. Functional shoes such as walking shoes have special functions to improve body motility by changing of shoe shapes. The walking shoes could improve the motility by structural transformation of outsole as increase degrees of heel and toe. The study on insoles has not been conducted enough on the contrary of the study of outsole. The purpose of this study is to perform ergonomics analysis whether the Arch Supported insoles have an improving effect of muscle activities or not. Experiments were performed with 6 subjects who are health and haven't experienced any diseases past. EMG(Electromyography) and Foot Pressures were measured repeatedly for 5 seconds at 0 hour, after 1 hour and after 2 hours of walking. Insoles used for experiment are normal insole, insole inserted Arch Support and pad. The electrodes for EMG measurement were set on waist (erector spinae), and thigh (vastus lateralis), calf (gastrocnemius). Evaluations of EMG were analyzed by shift of MF (Median Frequency) and MPF (Mean Power Frequency). Foot Pressure was analyzed by mean pressure of feet and change of walking time. As results, Arch Support insole had larger frequency shift value than that of normal insole. Frequency shift between Arch Support insoles and normal insole showed significant difference on 95% confidence interval. And insole 1 has the highest value of frequency shift. For results of foot pressure, Arch Support insoles show continuous decreasing tendency when comparing with normal insoles by changing of times. Also, insole 1 has the highest decreasing value of foot pressure. Therefore, this study presented that the Arch Support insole can promote muscle activities and improves comfort for a prolonged walking.

• 제어로봇시스템학회논문지
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• 제21권7호
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• pp.669-676
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• 2015

In this paper, we described the simulation results of the phase offset performance of a clock in holdover mode which was normally operated in GPS Disciplined Oscillator (GPSDO). In the TIE model, we included the time error term caused by environmental temperature variation because one of the most important parameters of clock phase error is the frequency offset and drift caused by the variation of temperature. For the simulation, we employed Maximum Time Interval Error (MTIE) for the performance evaluation when the frequency offset and drift are estimated by using an Unbiased Finite Impulse Response (UFIR) filter with ladder algorithm. We assumed that the noise in the GPS measurement is white Gaussian with zero mean and 1 ns standard deviation, and temperature linearly varies with a slope of $1{^{\circ}C}$ per hour. From the simulation results, the followings were observed. First, with the estimation error of temperature of less than 3 % and the temperature compensation period of less than 900 seconds, the requirement of CDMA2000 phase synchronization under 10 us could be achieved for more than 40,000 seconds holdover time if we employ an OCXO (Oven Controlled Crystal Oscillator) clock. Second, in order to achieve the requirement of LTE-TDD under 1.5 us for more than 10,000 seconds holdover time, below 3 % estimation error and 500 seconds should be retained if a Rubidium clock is adopted.

• 한국ITS학회 논문지
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• 제16권6호
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• pp.112-123
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• 2017

정부의 대중교통활성화 정책과 이용자들의 승용차에서 버스나 지하철로의 수단 전환으로, 대중교통의 정확한 배차시간과 도착시간의 확보가 중요해졌다. 서울시에서 제공하는 버스운행관리시스템(BMS : Bus Management System) 자료를 이용하여, 실시간 버스위치, 배차간격, 운행이력 등의 정보를 알 수 있다. 본 연구에서는 BMS 자료를 이용하여 안전운행을 하면서 정시성도 확보할 수 있는 방안을 제안하고자 한다. 다른 연구와는 다르게, 버스 정류장 사이 구간을 5개의 지점과 6개의 시간으로 나누어, 각각의 시간을 BMS 자료를 이용하여 산정하였다. 또한, 각 시간에 영향을 주는 주된 원인을 살펴보고, 요소별 평균, 표준편차, 변동계수를 이용하여 정류장 별 정시성과 안전성, 이동성을 모두 확보한 버스 노선의 적정 운행시간을 제안하였다.

• Physical Therapy Rehabilitation Science
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• 제6권1호
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• pp.7-13
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• 2017

Objective: The aim of this study was to investigate the inter-rater and intra-rater reliability of rehabilitative ultrasound imaging (RUSI) for measurement of muscle thickness with changes in angles of the gluteus maximus (GM) at rest and during contraction. Design: Cross-sectional study. Methods: Twenty-two healthy men volunteered for this study. GM muscle images were obtained in the resting position and during prone hip extension with knee flexion at hip abduction angles of $0^{\circ}$ and $30^{\circ}$, respectively. Two examiners randomly measured the thickness of the GM twice in three different positions. The first position was a comfortable prone position. The second position was prone hip extension with knee flexion (PHEKF) to $90^{\circ}$. The third position was achieved by hanging a 1-kg weight on the ankle of the lifted leg during PHEKF with the angle of the lifted leg the same as the second position. Intra-class correlation coefficients (ICCs), standard error measurements, and minimal detectable changes were used to estimate reliability. Results: The intra-rater reliability ICCs (95% confidence interval) of the GM were >0.870, indicating good reliability. Inter-rater reliability ICCs ranged from 0.668 to 0.913. The reliability of measurements of muscle thickness at each position was similar to the reliability of the angle change. Differences in muscle thickness and ratios for each position with $0^{\circ}$ and $30^{\circ}$ of hip abduction were not statistically significant. Conclusions: In the present study, the intra-rater reliability of muscle thickness measurements of the GM was good, and the inter-rater reliability was moderate to good. Reliable RUSI measurements of wide and large muscles, such as the GM muscle at rest and during contraction, are feasible. Further investigation is required to establish the reproducibility of the protocols presented in this study.

• 자원환경지질
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• 제25권2호
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• pp.167-177
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• 1992

The gravity measurement has been conducted at 53 and 34 stations with an interval of 1~1.5 km along the national roads of about 47 km and 34 km running from Duksungri to Yangpori and from Angangri to Byungpori, Kyungsangbookdo, respectively. The subsurface geology and geologic structure of Tertiary Pohang and Janggi basins along two survey lines are interpreted quantitatively by applying Fourier series and Talwani methods for Bouguer gravity anomaly. The depths of Conrad discontinuity vary from 11.8 to 12.5 km and 11.5 to 13.2 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. The depths of pre-Cambrian Gneiss complex underneath Kyungsang Supergroup vary from 3.8 to 4.2 km and 3.8 to 4.6 km along the survey lines between Duksungri and Yangpori, and Angangri and Byungpori, respectively. Massive granite bodies which are not exposed along the survey line between Duksungri and Yangpori are distributed on a large scale at the subsurface between Duksungri and Ochun, and Daegokri and Yangpori. Along the survey line between Angangri and Byungpori, it is exposed at Angangri, and extends underneath Chungrimdong, Pohang city. Andesite is distributed on a small scale underneath Pohang city and Ochun. The thicknesses of Tertiary Yonil and Janggi Groups are 0.2~0.9 km and 0.1~0.5 km, respectively. The Tuffaceous rocks which are the lowest formation of Tertiary sedimentary rocks are distributed with the thickness of 0.2 km at the surface and between Kyungsang Supergroup and Yonil or Janggi Groups. The Yonil and Janggi Groups are in fault contact by a fault running through Ochun and Chungrimdong, Pohang city. Two other faults are newly found near Heunghae-eup and Hyungsan river.

• 한국콘텐츠학회논문지
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• 제8권2호
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• pp.205-212
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• 2008

소아 환자는 정맥주사의 통증에 대한 심리적인 거부감 및 두려움이 존재하고 있다. 정맥 카데터 주입시의 통증을 평가하기 위해 CT검사를 위해 내원한 소아 130명(나이 $8{\sim}13$)을 대상으로 하였다. 통증 분석은 시각적 상사 척도(visual analog scale, VAS), 수치 통증 강도 척도(numeric pain rating scale, NPRS), Wong-Baker의 안면 통증 단계 척도(Wong-Baker faces pain scale, WBFPS)를 개량한 3종류의 평가 도구를 이용하였다. 시각적 상사 척도, 수치 통증 강도 척도, Wong-Baker의 안면 통증 단계 척도 간의 양의 상관관계($r=0.70{\sim}0.92$)를 보이고 있다. 시각적 상사 척도/수치 통증 강도 척도에서 보다 좋은 일치도를 나타냈다.

• 대한한방내과학회지
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• 제22권3호
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• pp.341-351
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• 2001

Object: Acori graminei rhizoma(AGR) extract is clinically used to treat the cerebral ischemia in Korea. The present study was undertaken to study the neuroprotective effect of AGR extract in middle cerebral artery occlusion(MCAO) rats. Methods: Changes of extracellular levels of glutamate, aspartate, GABA, glycine, taurine, tyrosine, alanine in striatum were collected at 20 minutes interval by in vivo microdialysis and then analyzed by HPLC(high performance liquid chromatography) in rats subjected to permanent focal cerebral ischemia induced by 2 hours of MCAO. AGR extract was orally administrated before MCAO. Different animals were used for measurement of cerebral infarction volume induced by 24 hours of MCAO with TTC staining and image analysis. Result : The infarction volume was decreased and focal cerebral ischemia - induced increase of extracellular glutamate, aspartate, and tyrosine were inhibited after the treatment of AGR extract. On the other hand, the increase of glycine and alanine not but GABA and taurine were enhenced after the treatment of AGR extract. Conclusion: These results suggest that AGR extract can playa role in protecting against cerebral ischemia by regulating extracellular levels of excitatory and inhibitory amino acid neurotransmitters.