• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.233-240
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• 2000

A commercially available Doppler radar was modified and evaluated for on-board monitoring of ground speed. The radar output was corrected for pitch angle of aircraft based on the output of an electrolytic tilt sensor. The effects of aircraft speed, height and mounting angle on error in the ground speed were evaluated. The speed error decreased with an increase of the mounting angle since the radar contact angle with respect to the ground approached to the mounting angle. The error increased with an increase of the nominal aircraft speed. The altitude insignificantly affected the speed error. The Doppler radar provided acceptable percent errors within 5% in most measurements. The error can be reduced within ${\pm}$1.5% by increasing the mounting angle ($43^{\circ}$). The error of -3.8% at the mounting angle of $29^{\circ}$could be reduced by adjusting the mounting angle with respect to the radar contact angle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.747-748
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.98-98
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• 2000

In this paper, we present a Multiheading Method for INS initial. The system is not observable for initial alignment however using pseudo tilt angles and pseudo sensor errors become observable. We suggest a new Multiple Method to find the real sensor errors by using the converted system dynamics. The results show that we can find the sensor errors very accurately by the proposed method.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.1-9
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• 2020

Purpose : The aim of this study was to compare the effects of the abdominal draw-in exercise (ADIE) and the dead bug exercise (DBE) on the pelvic anterior tilt angle and the activities of the gluteus maximus (GM), erector spinae (ES), and semi tendinosus (ST) during prone hip extension. Methods : A total of 22 female adults with weak abdominal muscles were divided into two groups: ADIE group (n=11) and DBE group (n=11). The muscle activities of the GM, ES, and ST along with the pelvic anterior tilt angle during prone hip extension were measured using a wireless surface electromyograph and gyro sensor before performing the prescribed exercise. Two groups conducted the assigned exercise for 10 minutes. After the exercise, their muscle activities and the pelvic anterior tilt angle were equally re measured. Results : In the DBE group, the muscle activity of GM was significantly increased after the intervention (p<0.05). However, there was no significant difference between the two groups in the amount of increase in the activity of GM (p>0.05). Moreover, in both groups, the activity of ES and the pelvic anterior tilt angle decreased significantly after the intervention (p<0.05) The decreased quantity in the pelvic anterior tilt angle and in the activity of ES showed no difference between the two groups (p>0.05). In the activity of ST, there was no significant difference within and between the two groups (p>0.05). Conclusion : Therefore, we suggest that ADIE and DBE are effective for women with weak abdominal muscles since the ES activity and pelvic anterior tilt angle are reduced during prone hip extension.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.145-152
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• 2010

Gait phase detection is important for evaluating the recovery of gait ability in patients with paralysis, and for determining the stimulation timing in FES walking. In this study, three different motion sensors(tilt sensor, gyrosensor and accelerometer) were used to detect gait events(heel strike, HS; toe off, TO) and they were compared one another to determine the most applicable sensor for gait phase detection. Motion sensors were attached on the shank and heel of subjects. Gait phases determined by the characteristics of each sensor's signal were compared with those from FVA. Gait phase detections using three different motion sensors were valid, since they all have reliabilities more than 95%, when compared with FVA. HS and TO were determined by both FVA and motion sensor signals, and the accuracy of detecting HS and TO with motion sensors were assessed by the time differences between FVA and motion sensors. Results show of that the tilt sensor and the gyrosensor could detect gait phase more accurately in normal subjects. Vertical acceleration from the accelerometer could detect HS most accurately in hemiplegic patient group A. The gyrosensor could detect HS and TO most accurately in hemiplegic patient group A and B. Valid error ranges of HS and TO were determined by 3.9 % and 13.6 % in normal subjects, respectively. The detection of TO from all sensor signals was valid in both patient group A and B. However, the vertical acceleration detected HS validly in patient group A and the gyrosensor detected HS validly in patient group B. We could determine the most applicable motion sensors to detect gait phases in hemiplegic patients. However, since hemiplegic patients have much different gait patterns one another, further experimental studies using various simple motion sensors would be required to determine gait events in pathologic gaits.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.247-251
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• 2015

In this study, electroglottographic spectral tilt (EST) was investigated for characterization of vocal cords vibration. EST was analyzed from the power spectrum of electroglottographic signals by dividing frequency analysis range as full range (0~4 octave), low range (0~2 octave), and high range (2~4 octave). EST of all ranges in female were greater than those in male. In female and male groups, EST of high range was higher than that of low range. This result suggests that EST has at least two components and dividing frequency range in analysis of EST is effective for investigating characteristics of vocal cords vibration.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.309-315
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• 2020

This study shows a control strategy that acquires both precision and manipulation sensitivity of remote center motion with manual traction for a surgical assistant robot. Remote center motion is an essential function of a laparoscopic surgical robot. The robot has to keep the position of the insertion port in a three-dimensional space, and general laparoscopic surgery needs 4-DoF (degree-of-freedom) motions such as pan, tilt, spin, and forward/backward. The proposed robot consists of a 6-axis collaborative robot and a 2-DoF end-effector. A 6-axis collaborative robot performs the cone-shaped trajectory with pan and tilt motion of an end-effector maintaining the position of remote center. An end-effector deals with the remaining 2-DoF movement. The most intuitive way a surgeon manipulates a robot is through direct teaching. Since the accuracy of maintaining the remote center position is important, direct teaching is implemented based on position control in this study. A force/torque sensor which is attached to between robot and end-effector estimates the surgeon's intention and generates the command of motion. The predefined remote center position and the pan and tilt angles generated from direct teaching are input as a command for position control. The command generation algorithm determines the direct teaching sensitivity. Required torque for direct teaching and accuracy of remote center motion are analyzed by experiments of panning and tilting motion.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.737-747
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• 2011

5678SMRT has installed various sensor for operating conditions(field of electric, facilities, signal, communication equipment and track) and environment of Every Function Room for remotely detecting and monitoring. Installed sound sensor for analyzed after remotely heard the noise of every equipment at Every Function Room and temperature sensor for check the temperature condition of Every Function Room. Additional installed voltage sensor in signal equipment room for monitoring RF track-circuit's voltage condition. Installed displacement sensor at The Chungdam bridge's railway for measuring and monitoring track displacement caused by temperature change and Pan/Tilt camera at sub-station and drainage for remotely field monitoring. Installed sensor for each equipment's operating condition and failure at Every Function Room then periodic check of workforce turned to around-the-clock surveillance by sensor therefore improvement of operating equipment. SMRT is lots of prevent a failure by Immediately detect of precondition of equipment failure by analyzed the sensor data. If the occurrence of an failure, become detected Immediately so possibility correct diagnosis and order by remotely field check by installed camera and sound sensor at field.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.742-745
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• 2009

This paper proposes a wireless LAN antenna system that tracks an object automatically by using image-based tracking. The proposed system consists of a camera and a pan-tilt unit in addition to a directional wireless LAN antenna. The camera and the directional antenna are set in same direction and they are set on the pan-tilt unit. A target object which has a wireless LAN receiver is tracked by using images captured by the camera. And the directional antenna faces in same direction as the camera by the pan-tilt unit. Therefore, the directional antenna keeps pointing the receiver, and a transmitting efficiency is improved. A result of a fundamental experiment shows that a receiver attached to a flying airship was tracked by a prototype of the proposed antenna system. The airship flied about, and the proposed antenna system was set on a roof of a building. The experimental result indicates an effectiveness of the proposed system compared to the conventional directional LAN antenna.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.93-99
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• 2015

Economic burden of work-related musculoskeletal disorder(WMDs) is increasing. Known causes of WMDs include improper posture, repetition, load, and temperature of workplace. Among them, improper postures play an important role. A smart sensor called SensorTag is employed to estimate the trunk postures including flexion-extension, lateral bend, and the trunk rotational speeds. Measuring gravitational acceleration vector in the smart sensor along the tri-orthogonal axes offers an orientation of the object with the smart sensor attached to. The smart sensor is light in weight and has small form factor, making it an ideal wearable sensor for body posture measurement. Measured data from the smart senor is wirelessly transferred for analysis to a smartphone which has enough computing power, data storage and internet-connectivity, removing need for additional hardware for data post-processing. Based on the estimated body postures, WMDs risks can be conviently gauged by using existing WMDs risk assesment methods such as OWAS, RULA, REBA, etc.