• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.31-39
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• 2013

A Quad Tilt Wing UAV is a new concept hybrid UAV having the advantages of both fixed-wing and rotary-wing aircraft. This paper presents longitudinal flight dynamic characteristics of a Quad Tilt Wing UAV. The designed Quad Tilt Wing UAV is a configuration of a tandem wing type aircraft with an actuating motor and propeller mounted at each wing. Momentum theory is used to calculate the thrust, and nonlinear modeling is performed considering lift and drag generated by slip stream effect of propellers. Also, Force and moment variation at each tilting angle is considered. Static trim on longitudinal axis is analyzed via numerical simulation. Componentwise force contribution was analyzed at each trim mode. Dynamic characteristics were evaluated through eigenvalue analysis for a linear model at each flight mode. It is verified that longitudinal dynamic characteristics are changing from unstable to stable state by continuous transition of dominant poles.

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.112-117
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• 2012

This report evaluated the convenience and accessibility of a penile translocation surgery in the lateral recumbency of a calf using a tilt-up mobile compared with that of dorsal recumbency on the ground of a barn. One nine-month-old F-1 (Korean native sire x Holstein dam) calf was sedated with xylazine (0.03 mg/kg, IV) and restrained in the right lateral recumbency position on a tilt-up restraint mobile (90 cm high), whereas the other nine-month-old Korean native calf was administered xylazine (0.3 mg/kg, IV) and restrained in dorsal recumbency position on the ground of a barn, with assistance by one person. For the two calves, lidocaine was administered subcutaneously from the preputial orifice to the S-shaped penis. The preputial orifice was incised, and the preputial sheath and penis were separated bluntly, then laterally translocated to the site toward the left flank at a $40^{\circ}$ angle. Anti-inflammatory drug (ketoprofen) and antibiotics (penicillin) were administered following the surgery. The duration of surgery was 30 min shorter in the calf that received the surgery in lateral recumbency using the tilt-up mobile with operator's standing posture (60 min) than the one that underwent surgery in dorsal recumbency on the ground with operator's bending posture (90 min). One week after the surgery, the operation area, including the translocated preputial orifice, was healed without complications in both cases. The results detailed in this report demonstrate that penile translocation surgery in the lateral recumbency position using a tilt-up mobile might be used conveniently in calves due to the convenience of restraint, reduced surgery time, and reduced physical inconvenience for the surgeon.

• Physical Therapy Rehabilitation Science
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• v.9 no.3
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• pp.140-148
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• 2020

Objective: The purpose of this study was to examine the effectiveness of pelvic displacement when self-hamstring muscle stretches were applied to persons with low back pain. Design: Three-group pretest-posttest design. Methods: Forty persons with low back pain participated in this study. Pelvic tilt angle, hamstring flexibility, Quadruple Visual Analogue Scale (QVAS), Fear Avoidance Beliefs Questionnaire (FABQ), Korea version of the Oswestry Disability Index (KODI) and pelvic mobility were measured at pre-post. All participants were divided into either the pevic anterior tilt group (PAT group, n=12), pelvic midrange group (PMR group, n=18), or the pelvic posterior tilt group (PPT group, n=10). Self-stretching was performed using the pilates ring three times a week for a total of four weeks and the post-test was conducted and compared with the pre-test. Results: Hamstring flexibility, QVAS, KODI scores were significantly different compared to before the intervention (p<0.05). The changes in hamstring flexibility of the three groups were significantly different (p<0.05). Changes in KODI and FABQ results of the three groups were not significant. The pelvic posterior tilt range were significantly different in the PMR and PPT groups (p<0.05). The pelvic anterior tilt ranges showed significant differences after stretching in the PPT group (p<0.05). Conclusions: A large amount of change of hamstring flexibility, pelvic mobility of anterior and posterior tilt test in the PPT group was observed. Furthermore, therapists should consider pelvic displacement of the participant when applying intervention, which may, accordingly, have different effectiveness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.84-88
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• 2023

This study proposes an automated tilt measurement method using point cloud for buildings. The proposed method consists of two main steps: 1) exterior wall plane extraction, and 2) edge estimation and angle calculation. To validate the performance of the proposed method, the algorithm is applied to a target building, of which the estimated tilt values are compared with those obtained from a total station, a commonly used tool for tilt measurement. The result shows that most estimated tilt values are within the maximum and minimum ranges of the total station measurement, suggesting that the proposed algorithm provides sufficient measurement accuracy. Furthermore, the proposed method is shown to be automated and reliable as well as free from human-induced errors compared to the total station.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.3
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• pp.116-124
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• 2011

In this study, a new method to estimate the bridge deflection is developed by using Wireless Tilt Sensor. Most of evaluations of structural integrity, it is very important to measure the geometric profile, which is a major factor representing the global behavior of civil structure, especially bridges. In the past, Because of the lack of appropriate methods to measure the deflection curve of bridges on site, the measurement of deflection had been done restrictly within just a few discrete points along the bridge. Also the measurement point could be limited to locations installed with displacement transducers. So, in this study, the deflection of the structure was measured by wireless tilt sensor instead of LVDT(Linear Variable Differential Transformer). Angle change of tilt sensor shows structural behavior by the change of the resistor values which is presented to voltage. Moreover, the maximum deflection was calculated by changing the deflection angle which was calculated as V(measured voltage) ${\times}$F(factor) to deflection. The experimental tests were carried out to verify the developed deflection estimation techniques. Because the base of tilt measuring is the gravity, uniform measurement is possible independent of a measuring point. Also, measuring values were showed very high accuracy.

• Progress in Medical Physics
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• v.27 no.1
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• pp.14-24
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• 2016

Since the head and neck region is densely located with organs at risk (OAR), OAR-sparing is an important issue in the treatment of head and neck cancers. This study-in which different treatment plans were performed varying the head tilt angle on brain tumor patients-investigates the optimal head elevation angle for sparing normal organs (e.g. the hippocampus) and further compares the dosimetric characteristics of different types of radiation equipment. we performed 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and tomotherapy on 10 patients with brain tumors in the frontal lobe while varying the head tilt angle of patients to analyze the dosimetric characteristics of different therapy methods. In each treatment plan, 95% of the tumor volume was irradiated with a dose of 40 Gy in 10 fractions. The step and shoot technique with nine beams was used for IMRT, and the same prescription dose was delivered to the tumor volume for the 3D-CRT and tomotherapy plans. The homogeneity index, conformity index, and normal tissue complication probability (NTCP) were calculated. At a head elevation angle of $30^{\circ}$, conformity of the isodose curve to the target increased on average by 53%, 8%, and 5.4%. In 3D-CRT, the maximum dose received by the brain stem decreased at $15^{\circ}$, $30^{\circ}$, and $40^{\circ}$, compared to that observed at $0^{\circ}$. The NTCP value of the hippocampus observed in each modality was the highest at a head and neck angle of $0^{\circ}$ and the lowest at $30^{\circ}$. This study demonstrates that the elevation of the patients' head tilt angle in radiation therapy improves the target region's homogeneity of dose distribution by increasing the tumor control rate and conformity of the isodose curve to the target. Moreover, the study shows that the elevation of the head tilt angle lowers the NTCP by separating the tumor volume from the normal tissues, which helps spare OARs and reduce the delivered dose to the hippocampus.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.53-54
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• 2006

We have studied the viewing angle control of a twist nematic liquid crystal display (TN-LCD). The TN-LCD exhibits a bad image quality along vertical direction, due to characteristics such as low contrast ratio and grey scale inversion. The proposed new TN-LCD has the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers at both sides of a TN-cell Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.699-702
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• 2006

We have developed twist nematic liquid crystal displays (TN-LCDs), of which the viewing angle can be controlled. The TN-LCDs have the function of switching between the wide viewing mode and narrow viewing angle mode using two tilted LC layers. Tilt angles of the two LC layers, $14^{\circ}$ and $60^{\circ}$ were required in both wide viewing angle and narrow viewing angle modes, respectively. In this way, the viewing angle range in terms of contrast ratio 5:1 can be switched from $120^{\circ}$ to $60^{\circ}$.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.457-459
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• 2005

Low viscosity LCs have been developed for fast response time improvement of the TFT-LCD Monitors based on TN mode. This low viscosity characteristic s cause the pretilt angle to be changed and the uniformity to degrade. We have studied on the pretilt angle effect by the various components used for low viscosity LCs. We prepared the panels by using these various components and measured pretilt angle for this research. As a result of this research, we have found out that each low viscosity component has the different pretilt angle level and uniformity. For good display quality, it is important to keep the stable pretilt angle. The low viscosity LCs with this stable pretilt angle make it possible to prepare the high performance TFT-LCD Monitor with both fast response time characteristics and good display quality

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.100-100
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• 2016

전자파표면유속계는 대표적인 비접촉식 계측기기로 최근 유량조사를 위해 활발하게 활용되고 있다. 국내에서 사용되고 있는 전자파표면유속계는 평수기 저유속에서도 측정이 가능하고 편각 측정이 가능하도록 개발되어 한 측정 지점에서 다 지점의 유속이 측정이 가능해 평수기 홍수기에 비교적 적은 인원으로 빠른 시간에 유량측정이 가능하다. 하지만 국내의 경우 전자파표면유속계가 과연 얼마만큼의 정확한 유속을 측정하는지에 대한 분석이 다소 부족한 실정으로 특히, 실제 하천에서 정확한 분석은 수행되지 않은 상태에서 유량 측정에 사용되고 있다. 전자파표면유속계를 실제 하천에서 사용할 경우 발생 할 수 있는 오차의 요인으로는 교량과 같이 높은 지점에서 측정을 수행할 경우 측정영역(Footprint or Illuminated area)에 따른 오차가 발생할 수 있는 가능성이 있고, 동일 측정 지점에 대해 수직각과 편각에 변화에 따른 유속 측정 오차가 발생할 수 있다. 이에 본 연구에서는 국내에서 개발된 Mutronics사의 전자파표면유속계(MWSCM; Microwave Water Surface Current Meter)에 레이저포인터를 부착하여 표면유속 약 0.5m/s ~ 1m/s의 자연 하천과 매우 유사한 실제 소하천 규모의 한국건설기술연구원 안동실험센터 직선하천에서 수직각(Tilt angle) 및 편각(Yaw angle)을 변화시켜가며 유속를 측정하였다. 그리고 측정된 결과를 활용하여 수직각과 편각의 변화에 따른 전자파표면유속계의 측정영역을 검토하였고, 동일한 측정 지점에 micro-ADV를 이용해 측정된 연직유속분포를 외삽하여 산정된 표면유속과 비교하여 전자파표면유속계의 측정 정확도를 분석하였다. 분석결과, 수직각(Tilt angle) 15도 이하에서는 유속 측정의 정확도가 떨어지는 것으로 나타났고, 편각(Yaw angle)이 커질수록 측정영역이 커지게 되어 변동 계수가 증가하는 것으로 나타났다. 그리고 전자파표면유속계의 측정 오차는 측정영역에 민감하게 반응하는 것으로 나타나 실제 전자파표면유속계를 이용한 유량측정 시 측정영역을 고려한 측정이 수행되어야 할 것으로 판단된다.