• 한국방사선학회논문지
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• 제11권6호
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• pp.501-508
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• 2017

방사선치료에 사용하는 CT 스캐너에 의해 획득된 CT 및 CBCT 전자밀도팬텀의 CT영상부터 CT수 대 물리적 밀도 변환에 관한 CT 스캐닝 매개변수의 의존성은 실험으로 분석하였다. CT수는 관전류량, 슬라이스 두께, 영상재구성 필터, 시야 그리고 팬텀 용적의 크기에 대해 의존하지 않았다. 그러나 CT수는 관전압과 팬텀 횡단면적 크기에 의존하였다. 결과로서, 물리적 밀도 1이상의 범위에 대하여, 90과 120 kVp 사이의 관전압에서 관측된 최대 CT수 차이는 27%이었고, 그리고 CT 몸통과 머리 전자밀도팬텀 사이에서 관측된 최대 CT수 차이는 15%이었다.

• Smart Structures and Systems
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• 제19권3호
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• pp.269-277
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• 2017

Recently, there has been significant interest in structural health monitoring for civil engineering applications. In this research, a specially designed tendon, proposed by embedding FBG sensors into the center king cable of a 7-wire strand tendon, was applied for long-term health monitoring of tensile forces on a ground anchor. To make temperature independent sensors, the effective temperature compensation of FBG sensors must be considered. The temperature sensitivity coefficient ${\beta}^{\prime}$ of the FBG sensors embedded tendon was successfully determined to be $2.0{\times}10^{-5}^{\circ}C^{-1}$ through calibrated tests in both a model rock body and a laboratory heat chamber. Furthermore, the obtained result for ${\beta}^{\prime}$ was formally verified through the ground temperature measurement test, expectedly. As a result, the ground temperature measured by a thermometer showed good agreement compared to that measured by the proposed FBG sensor, which was calibrated considering to the temperature sensitivity coefficient ${\beta}^{\prime}$. Finally, four prototype ground anchors including two tension ground anchors and two compression ground anchors made by replacing a tendon with the proposed smart tendon were installed into an actual slope at the Yeosu site. Tensile forces, after temperature compensation was taken into account using the verified temperature sensitivity coefficient ${\beta}^{\prime}$ and ground temperature obtained from the Korean Meteorological Administration (KMA) have been monitored for over one year, and the results were very consistent to those measured from the load cell, interestingly.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4447-4453
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• 2013

Purpose: To investigate the risk factors for anastomotic leakage (AL) after anterior resection for rectal cancer with a double stapling technique. Patients and Methods: Between January 2004 and December 2011, 753 consecutive patients in Jiangsu Cancer Hospital and Research Institute diagnosed with rectal cancer and undergoing anterior resection with a double stapling technique were recruited. All patients experienced a total mesorectal excision (TME) operation. Additionally, decrease of postoperative tumor supplied group of factors (TSGF), which have not been reported before, was proposed as a new indicator for AL. Univariate and multivariate analysis were performed to determine risk factors for AL. Results: AL was detected in 57 (7.6%) of 753 patients with rectal cancer. The diagnosis of anastomotic leakage was confirmed between the 6th and 12th postoperative day (POD; mean 8th POD). After univariate analysis and multivariate analysis, age (p<0.001), gender (p=0.002), level of anastomosis (p<0.001), preoperative body mass index (BMI) (p=0.001) and reduction of TSGF in 5th POD was less than 10 ${\mu}/ml$ (p<0.001) were selected as 5 independent risk factors for AL. It was also indicated that a temporary defunctioning transverse ileostomy (p=0.04) would decrease the occurrence of AL. Conclusion: AL after anterior resection for rectal carcinoma is related to elderly status, low level site of the tumor (below the peritoneal reflection), being male, preoperative BMI and the decrease of TSGF in $5^{th}$ POD is less than 10 ${\mu}/ml$. Preventive ileostomy is advisable after TME for low rectal tumors to prevent AL.

• 대한전자공학회논문지
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• 제25권10호
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• pp.1173-1182
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• 1988

보행로보트에 있어서 다리의 기구적 특성은 안정도, 에너지 효율 및 걷는 영역 등에 영향을 준다. 보행로보트 중에서 안정도 여유가 비교적 큰 사각보행로보트는 보폭이 크다. 그리고 수직운동과 수평운동이 서로 분리되어 있는 팬토그래프 구조의 다리를 갖는 보행로보트는 기구적인 복잡성으로 인하여 움직임을 예상하기가 어렵게 된다. 따라서, 보행로보트의 3차원적인 이동을 해석하기 위하여 그래픽스를 이용한 방법이 중요하게 쓰일 수 있다. 본 논문에서는 서로 다른 조인트 구동방식을 갖는 세 개의 사각보행로보트를 모델링하고, 각각에 대하여 몸의 중심으로 표시된 경로로써 작업지시를 하여 걷는 모습을 애니메이션 함으로써 그 기구적인 특성을 해석할 수 있게 하였다. 그리고 회전걸음이나 옆걸음을 위하여 다리 제어를 하였고, 조인트의 이동에 대한 정보를 위하여 Sun-3 시스템에서의 윈도우를 이용하였다.

• Journal of Magnetics
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• 제14권4호
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• pp.137-143
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• 2009

The convergence behavior of the all-electron full-potential linearized augmented plane-wave (FLAPW) method with the explicit orthogonalization (XO) scheme is tested on ferromagnetic bulk body-centered-cubic Fe. Applying a commonly used criterion relating the plane-wave and angular momentum cutoffs, $l_{max}\;=\;R_{MT}K_{max}$, where $R_{MT}$ is the muffin-tin (MT) sphere radius and $K_{max}$ is the plane-wave cutoff for the basis - the total energy is converged and stable for $K_{max}R_{MT}$ = 10. The total energy convergence dependence on the star-function cutoff, $G_{max}$, is minimal and so a $G_{max}$ of 3$K_{max}$ or a large enough $G_{max}$ is a reasonable choice. We demonstrate that the convergence with respect to $l_{max}$ or a fixed large enough $G_{max}\;and\;K_{max}$ are independent, and that $K_{max}$ provides a better measure of the convergence than $R_{MT}K_{max}$. The dependence of the total energy on $R_{MT}$ is shown to be small if the core states are treated equivalently, and that the XO scheme is able to treat systems with significantly smaller $R_{MT}$ than the standard LAPW method. For converged systems, the calculated lattice parameter, bulk modulus, and magnetic moments are in excellent agreement with the experimental values.

• PNF and Movement
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• 제15권2호
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• pp.195-200
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• 2017

Purpose: This study attempts to identify the effects of stretching and core exercise using proprioceptive neuromuscular facilitation (PNF) on the pain and functional disability index of patients with chronic lower back pain. Methods: A total of 20 patients with chronic lower back pain were randomly divided into either the experimental group (n=10), who received PNF stretching and core exercise, or the control group (n=10), who received conventional physiotherapy. Both interventions were applied three times a week for six weeks. The visible analogue scale (VAS) was measured in order to determine the level of pain, while the Oswestry Disability Index (ODI) was used to measure the change in the functional disability index. We conducted a paired t-test to compare the within-group change before and after the intervention. To compare the between-group difference, we used an independent t-test. The statistical significance level was set at ${\alpha}=0.05$ for all the variables. Results: The experimental group showed a significant within-group change in both the VAS and the ODI (p<0.01). The control group also showed a significant change (p<0.01). A significant difference was observed between the experimental group and the control group with regard to the change in both the VAS and the ODI after the interventions (p<0.01). Conclusion: In this study, the application of stretching and core exercise using PNF for subjects who complain of chronic lower back pain proved effective in reducing both pain and functional disability. We therefore expect that this intervention can be applied in the future as a useful program for patients with chronic lower back pain.

• Journal of Preventive Medicine and Public Health
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• 제47권3호
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• pp.150-157
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• 2014

Objectives: The decrease or increase in sleep duration has recently been recognized as a risk factor for several diseases, including hypertension and obesity. Many studies have explored the relationship of decreased sleep durations and injuries, but few have examined the relationship between increased sleep duration and injury. The objective of this research is to identify the risk for injury associated with both decreased and increased sleep durations. Methods: Data from the 2010 Community Health Survey were used in this study. We conducted logistic regression with average sleep duration as the independent variable, injury as a dependent variable, and controlling for age, sex, occupation, education, region (cities and provinces), smoking, alcohol use, body mass index, hypertension, diabetes, arthritis, and depression. Seven categories of sleep duration were established: ${\leq}4$, 5, 6, 7, 8, 9, and ${\geq}10$ hours. Results: Using 7 hours of sleep as the reference, the adjusted injury risk (odds ratio) for those sleeping a total of ${\leq}4$ h/d was 1.53; 1.28 for 5 hours, for 1.11 for 6 hours, 0.98 for 8 hours, 1.12 for 9 hours, and 1.48 for ${\geq}10$ hours. The difference in risk was statistically significant for each category except for the 8 and 9 hours. In this study, risk increased as the sleep duration decreased or increased, except for the 8 and 9 hours. Conclusions: This research found that either a decrease or increase in sleep duration was associated with an increased risk for injury. The concept of proper sleep duration can be evaluated by its associated injury risk.

• 한국운동역학회지
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• 제25권3호
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• pp.353-361
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• 2015

Objective : The aim of this study was to develop the non-powered horse riding device and was to evaluate the elaborate its applicability throughout static structural and transient structural analysis of the outdoor core strength exercise equipment. Method : Fifteen college students (mass: $69.55{\pm}13.38kg$, height: $1.69{\pm}5.61m$, age: $21.42{\pm}1.83yrs$) rode the powered horse riding device and 14 college students (mass: $71.12{\pm}9.74kg$, height: $1.73{\pm}3.31m$, age: $22.50{\pm}1.47yrs$) rode the non-powered horse riding device for the comparison. All motion capture data was collected at 100 Hz using six infrared cameras and the muscular activities were collected using a Delsys Trigno wireless system. The peak forward/backward lean angle, range of motion anter/posterior and vertical COM(Center of mass) movement of trunk and pelvis segment, and muscle activities of six muscles were compared between the two devices by using independent t-test (p<.05). Results : Several kinematic variables (peak forward-backward lean angle and vertical COM movement of trunk and pelvis segment, range of motion of trunk) significantly different between non-powered and powered horse riding device. The muscle activities of Rectus abdominis and External oblique of abdomen on the non-powered horse riding device were significantly greater than those of the powered device. Conclusion : It was concluded that non-power horse riding device could give the effect of core strength exercise as well as the body motion which can simulate the powered horse riding device.

• Tuberculosis and Respiratory Diseases
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• 제76권6호
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• pp.269-275
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• 2014

Background: The six-minute walk test has been widely used in people with chronic cardiopulmonary disorders as an outcome assessment with regards to therapeutic or prognostic determinants. This study was undertaken to determine the six-minute walk distance (6MWD) in a sample of healthy Koreans and to create a reference equation. We also compared the 6MWD of our cohort with previously published equations. Methods: Two hundred fifty-nine healthy subjects (95 males) aged 22-59 years performed two walking tests using a standardized protocol. 6MWD was defined as the greatest distance achieved from the two tests. The effect of anthropometrics on the 6MWD was also investigated. Results: The average 6MWD was $598.5{\pm}57.92m$, with significantly longer distances by males ($628.9{\pm}59.51m$) than females ($580.9{\pm}47.80m$) (p<0.001). Age, height, weight, and body mass index were significantly correlated with 6MWD in univariate analysis. Stepwise multiple regression showed height to be single independent predictor of 6MWD ($r^2$=0.205, p<0.001). The reference equations derived in Caucasian and North African populations tend to overestimate the distance walked by Korean subjects, while Asian equations underestimate it. Conclusion: The average 6MWD in these Korean populations was 600 m. The regression equation revealed that individual's height was the most significant predictor of distance, explaining 20.5% of the distance variance.

• Tuberculosis and Respiratory Diseases
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• 제81권3호
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• pp.233-240
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• 2018

Background: Non-conversion of sputum smear and culture prolongs the infectivity of the patient and has been associated with unfavorable outcomes. We aimed to evaluate factors associated with persistent sputum positivity at the end of two months of treatment of new case pulmonary tuberculosis (TB). Methods: Data of 87 human immunodeficiency virus-negative patients with culture-positive drug-susceptible pulmonary TB admitted to local university hospital between September 2015 and September 2016 were reviewed. Factors associated with sputum smear and/or culture positivity at the end of the second month of treatment were analyzed. Results: Twenty-two patients (25.3%) remained smear and/or culture-positive. Male sex, lower body mass index (BMI), unemployment, alcohol abuse, higher number of lobes involved and cavities on chest X-rays, shorter time to detection (TTD) on liquid cultures, higher respiratory sample smear grading and colony count in solid cultures, higher C-reactive protein, erythrocyte sedimentation rate, leukocytosis, thrombocytosis, and anemia were all significantly associated with persistent sputum positivity. However, in the logistic regression analysis only male sex, lower BMI, alcohol abuse, higher radiological involvement, cavitation, higher smear grading, higher colony count in solid cultures and shorter TTD were determined as independent factors associated with persistent sputum positivity at the end of 2 months of treatment. Conclusion: In conclusion, higher sputum smear and culture grading at diagnosis, shorter TTD, higher number of lobes involved, cavitation, male sex, alcohol abuse, and lower BMI were independently associated with persistent sputum positivity. These factors should be sought when distinguishing which patients will remain infectious longer and possibly have worse outcomes.