• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2017년도 추계학술대회
• /
• pp.121-122
• /
• 2017

본 논문에서는 목을 구부려 턱이 가슴에 닿도록 하는 굽힘과, 목을 들어 천장을 보는 것처럼 자세를 취하는 폄에 대하여 각을 측정한다. 굽힘의 각도는 $45{\sim}50^{\circ}$가 기본이며 최대의 가동 범위는 $80{\sim}90^{\circ}$이다. 폄의 각도 또한 $40^{\circ}{\sim}50^{\circ}$가 기본이며 정상은 $70^{\circ}$로 제한된다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.504-507
• /
• 2006

Airborn Lidar technology has been applied to diverse applications with the advantages of accurate 3D information. Further, Lidar intensity, backscattered signal power, can provid us additional information regarding target's characteristics. Lidar intensity varies by the target reflectance, moisture condition, range, and viewing geometry. This study purposes to generate normalized airborne LiDAR intensity image considering those influential factors such as reflectance, range and geometric/topographic factors (scan angle, ground height, aspect, slope, local incidence angle: LIA). Laser points from one flight line were extracted to simplify the geometric conditions. Laser intensities of sample plots, selected by using a set of reference data and ground survey, werethen statistically analyzed with independent variables. Target reflectance, range between sensor and target, and surface slope were main factors to influence the laser intensity. Intensity of laser points was initially normalized by removing range effect only. However, microsite topographic factor, such as slope angle, was not normalized due to difficulty of automatic calculation.

• 전기학회논문지
• /
• 제58권8호
• /
• pp.1526-1531
• /
• 2009

In this paper, for the first time a new type of narrow-range angle sensor based on inductive effect is introduced and studied. A prototype steering angle sensor is also designed and fabricated to compare the characteristics of the four methods from the viewpoints of sensitivity, linearity and resolution, angle range of the sensor output. This sensor is designed to be sensitive to very small resolution in angle with detected range is scaled down to about 12bit. An intensive investigation has been carried out to study the behaviors of the sensor and optimize its performance by signal compensation. These behaviors are discussed and explained using an analytical and experimental testings. Moreover, Application possibility of the sensor are proposed and a demo device based on the sensor is presented.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
• /
• pp.142-148
• /
• 1998

Recently for the impressive gains of performance and efficiency over vaneless diffuser with apparently little or no loss in flow range, the use of LSVD(Low Solidity Vaned Diffuser) is well recommended. The experiments on the effect of the vane turning angle variation(positive, negative, zero) with other design parameters fixed on the performance and flow range were carried out. Diffuser with zero turning angle has the best characteristics in terms of performance and efficiency and The FFT results show the different frequency characteristics due to the vane turning angle in low flow range.

• 산업기술연구
• /
• 제22권A호
• /
• pp.153-159
• /
• 2002

This paper is an experimental work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of $41{\sim}57^{\circ}$. The measured value of repose angle is in the range of $32{\sim}35^{\circ}$. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of $30{\sim}46^{\circ}$. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(l966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제39권
• /
• pp.4.1-4.7
• /
• 2017

Background: This study is a quantitative evaluation of the influence of the mentolabial angle on perceived attractiveness and threshold values of desire for surgery. Methods: The mentolabial angle of an idealized silhouette male Caucasian profile image was altered incrementally between $84^{\circ}$ and $162^{\circ}$. Images were rated on a Likert scale by pretreatment orthognathic patients (n = 75), lay people (n = 75) and clinicians (n = 35). Results: A mentolabial angle of approximately $107^{\circ}$ to $118^{\circ}$ was deemed the most attractive, with a range of up to $140^{\circ}$ deemed acceptable. Angles above or below this range were perceived as unattractive, and anything outside the range of below $98^{\circ}$ or above $162^{\circ}$ was deemed very unattractive. A deep mentolabial angle ($84^{\circ}$) or an almost flat angle ($162^{\circ}$) was deemed the least attractive. In terms of threshold values of desire for surgery, for all groups, a threshold value of ${\geq}162^{\circ}$ and ${\leq}84^{\circ}$ indicated a preference for surgery, although clinicians were least likely to suggest surgery. The clinician group was the most consistent, and for many of the images, there was some variation in agreement between clinicians and lay people as to whether surgery is required. There was even more variability in the assessments for the patient group. Conclusions: It is recommended that in orthognathic and genioplasty planning, the range of normal variability of the mentolabial angle, in terms of observer acceptance, is taken into account as well as threshold values of desire for surgery. The importance of using patients as observers in attractiveness research is stressed.

• 한국자동차공학회논문집
• /
• 제18권2호
• /
• pp.48-55
• /
• 2010

We have development the steering angle sensor using not only detecting parts but also integrating technique with semiconductors for automobile applications. The performance design and analysis of the steering angle sensor for intelligent vehicles is complicated due to variety of parameters. In this study, the performance characteristics of the angle sensor were analyzed using test rig. By means of magnetic induction technique, these new the steering angle sensors showed excellent magnetic characteristics. The detection range of steering angle sensor obtained was ${\pm}800^{\circ}$, the maximum non-linearity is 0.744% Full Span and the temperature range was $-40^{\circ}C{\sim}+125^{\circ}C$. With this conclusive, the inductive angle sensor was quite satisfactory for many applications in intelligent vehicles.

• Journal of Power Electronics
• /
• 제18권3호
• /
• pp.714-722
• /
• 2018

This paper presents a wide-range speed control scheme of brushless DC (BLDC) motors based on a hall sensor with separated low- and normal-speed controllers. However, the use of the hall sensor signal is insufficient to detect motor speed in the low-speed region because of low sensor resolution and time delay. In the proposed method, a micro-stepping current control method according to the torque angle variation is presented. In this mode, the motor current frequency and rotating angle are determined by the reference speed without the actual speed fed by the hall sensor. The detected torque angle is used to adjust the current value in a limited band to control the current value in accordance with the load. The torque angle is detected exactly at the changing point of the hall sensor signal. The rotor can follow the rotating flux with the variable torque angle. In a normal speed range, the conventional vector control scheme is used to control the motor current with a PI speed controller using the hall sensor. The torque characteristics are analyzed on the basis of the back EMF and current shape. To adopt the vector control scheme, the continuous rotor position is estimated by the measured speed and hall sensor position. At the mode changing point between low and normal speed range, the proper initial current command and reference rotor position are calculated. The calculated current command can reduce the torque ripple during transient mode. The proposed method is simple but effective in extending the speed control range of a conventional BLDC motor with hall sensor without the need for a high-resolution encoder. The effectiveness of the proposed method is verified by various experiments on a practical BLDC motor.

• 대한족부족관절학회지
• /
• 제21권4호
• /
• pp.135-138
• /
• 2017

Purpose: The purpose of this study is to determine the correlation between the correction loss of hallux valgus angle and the severity of valgus angle of the second toe. Materials and Methods: We selected 312 cases from 268 surgical patients with hallux valgus deformity receiving distal chevron osteotomy. For a radiological evaluation, we analyzed the changes in the hallux valgus angles, first to second intermetatarsal angles, and valgus angle of the second toe post index operations. All patients were women; the mean age was 46 years. The mean follow-up period was 17 months. Results: The mean hallux valgus angle was $33.6^{\circ}$ preoperatively (range, $25.7^{\circ}{\sim}44.8^{\circ}$), $13.1^{\circ}$ (range, $8.4^{\circ}{\sim}16.4^{\circ}$) after 4 weeks of postoperative period, and $17.1^{\circ}$ (range, $9.4^{\circ}{\sim}28.5^{\circ}$) at their final follow-up. The mean valgus angle of the second toe was $8.4^{\circ}$ preoperatively (range, $2.0^{\circ}{\sim}25.8^{\circ}$) and $8.3^{\circ}$ (range, $1.7^{\circ}{\sim}24.9^{\circ}$) at the final follow-up. Preoperatively, there was a positive correlation between the valgus angle of the second toe and hallux valgus angle (r=0.747, p=0.001). The correction loss of hallux valgus angle had a significant correlation with the severity of valgus angle of the second toe (r=0.802, p=0.001). Conclusion: The existence of the second toe valgus deformity may present itself as a cause of correction loss of hallux valgus angle. The preoperative measurement of the second toe valgus angle may be a good predictor of correction loss; therefore, thorough preoperative warning on the possibility of correction loss should be conducted to maximize patient satisfaction after the procedure.

• 한국방사선학회논문지
• /
• 제12권1호
• /
• pp.115-122
• /
• 2018

본 연구에서는 CT영상기반 3차원 고관절모델을 이용한 컴퓨터시뮬레이션을 통해서 고관절의 운동범위(Range of Motion)를 측정하는 방법을 제시하였다. 본 연구에서는 그 측정방법에 대한 기술적인 사항을 제시하고, 그 기술이 재현성 있게 실현할 수 있도록 대퇴골두 중심점의 결절, 대퇴골 외전(Abduction)/내전(adduction)회전축, 굽힙(flexion)/신전(extension) 회전축을 정의하고 측정하는 명확한 방법을 제시하였다. 외전각은 해부학적인 시상면(Sagittal plane)상의 Anterior-Posterior축에 대해 아래쪽(Inferior)면으로부터 Lateral 쪽으로의 회전각으로 정의된다. 최대외전각은 대퇴골두가 엉덩이뼈(Pelvis)의 절구(Acetabulum)의 테두리와 겹치지 않고 Anterior-Posterior축을 중심으로 회전할 수 있는 최대 외전각으로 결정된다. 굴곡각은 해부학적인 관상면(Coronal plane)상의 Medial-Lateral축에 대해 아래쪽(Inferior)면으로부터 회전각으로 정의된다. 최대굴곡각은 대퇴골이 Medial-Lateral축을 중심으로 엉덩이뼈(Pelvis)의 절구(Acetabulum)의 테두리와 겹치지 않고 회전할 수 있는 최대 굴곡각으로 결정된다. 정상고관절에 비해 인공고관절술을 받은 해당 환자의 경우, 외전에서는 60도 정도, 굽힘에서는 4도 정도 운동범위가 줄어들 수 있다는 예측이 나왔다. 본 연구에서 행한 시뮬레이션을 해보고 외전의 경우 운동범위의 감소가 예측되므로, 대퇴골두를 조금 큰 것을 고르거나 대퇴골목부의 길이 (femoral neck offset)를 길게 시술해야 할 필요가 있음을 의미한다.