• Journal of Institute of Control, Robotics and Systems
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• v.19 no.12
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• pp.1160-1166
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• 2013

This paper presents feedforward controllers to improve the control performance of the motion and grasping force of a surgical instrument used in an MIS (Minimally Invasive Surgery) robot. The surgical instrument has a long distance between the drive motors and its active joints. Therefore, the gripper on the instrument is controlled by a cable drive mechanism, which generates a coupled motion between the wrist joint and the grip direction. In order to solve the problem, this paper analyzes the pulley composition of the surgical instrument and proposes feedforward controllers to eliminate the coupled motion. Furthermore, feedforward controllers to regulate the grasping force are proposed to deal with another coupling problem between the grasping force of the instrument and the motion of the instrument joints. The experimental results demonstrate the improved control performance of the motion and grasping force of the instrument.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.2
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• pp.1-7
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• 2015

PURPOSE: The aims of this study were to assess the intra-tester and inter-tester reliability and validity of hip range of motion using a smart phone in hip operative patients. METHODS: Twenty-five patients (eight total hip arthroplasty and seventeen femur neck fracture) participated in this study. The range of motions in active and passive hip flexion, abduction and external rotation were measured with a goniometer and smart phone over two times by two observers. The intra-tester and inter-tester reliability were evaluated using the intraclass correlation coefficient (ICC2,1). The validity was measured by Pearson's correlation coefficient RESULTS: The intra-observer reliability was good in all measured items (ICC>0.78). The inter-observer reliability was high with ICC (>0.90). All correlation coefficients of smart phone and goniometer was greater than 0.85 and showed a significant positive correlation (p<0.01). CONCLUSION: The range of motion measurement with a smart phone showed acceptable reliability. Therefore, it could be convenient and have economical benefits to measure the range of motion of the hip joint using a smart phone.

• Journal of Wind Energy
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• v.14 no.4
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• pp.87-97
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• 2023

Due to the limitations of onshore wind power, the wind power industry is currently transitioning to offshore wind power. There has been active research on the development of a floating LiDAR system (FLS) that is easy to install at a low cost. The Carbon Trust published a commercialization roadmap for FLS in 2013, and an updated version was released in 2018, taking into account industry experience. The roadmap divides the development maturity of FLS into three stages: Stage 1 (prototype), Stage 2 (pre-commercialization), and Stage 3 (commercialization), each of which requires availability and accuracy assessment. The results must meet the requirements of the Key Performance Index (KPI) for each stage. Therefore, when developing FLS, the motion compensation algorithm of the FLS is essential because the LiDAR can produce incorrect measurements of wind speed and direction due to the six degrees of freedom in motion. In this study, we implemented the FLS motion compensation algorithm developed by Nassif, F.B. et al. and validated it using data provided by Fraunhofer. In conclusion, the results showed that the determination coefficients of wind speed and wind direction were improved compared to those obtained from the met mast.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.424-431
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• 2006

Many types of tuned mass dampers (TMDs), such as active TMDs, multiple TMDs, hybrid TMDs etc., have been studied to effectively reduce the dynamic responses of a structure subjected to various types of dynamic loads. In this study, we replace a passive damper by a semi-active tuned mass damper to improve the control performance of conventional TMDs (STMD). An idealized variable damping device is used as semi-active dampers. These semi-active dampers can change the properties of TMDs in real time based on the dynamic responses of a structure. The control performance of STMD is investigated with respect to various types of excitation by numerical simulation. Groundhook control algorithm is used to appropriately modulate the damping force of semi-active dampers. The control effectiveness between STMD and a conventional passive TMD, both under harmonic and random excitations, is evaluated and compared for a single-degree-of-freedom (SDOF) structure. Excitations are applied to the structure as a dynamic force and ground motion, respectively. The numerical studies showed that the control effectiveness of STMD is significantly superior to that of the passive TMD, regardless of the type of excitations.

• PNF and Movement
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• v.20 no.2
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• pp.215-222
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• 2022

Purpose: The purpose of this study was to compare the effects of passive scapular upward rotation and posterior tilt and active scapular posterior tilt on the muscle activity of the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA). Methods: Fifteen healthy subjects performed general arm elevation, arm elevation with passive scapular upward rotation and posterior tilt, and arm elevation with active scapular posterior tilt. For active scapular posterior tilt, the subjects were trained in this movement using visual biofeedback and a motion sensor. During each arm elevation condition, electromyography was used to measure the muscle activity of the UT, LT, and SA. The measured data were analyzed using a one-way repeated ANOVA. Results: LT muscle activity was significantly increased during arm elevation with active scapular posterior tilt compared to both general arm elevation and arm elevation with passive scapular upward rotation and posterior tilt (p < 0.05). SA muscle activity was greater during arm elevation with passive scapular upward rotation and posterior tilt than during general arm elevation (p < 0.05). There was no significant change in UT muscle activity among the tested arm elevation conditions (p > 0.05). Conclusion: Performing arm elevation with active scapular posterior tilt and performing arm elevation with passive scapular upward rotation and posterior tilt may be useful strategies for increasing muscle activation of the LT and SA, respectively.

• Earthquakes and Structures
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• v.6 no.2
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• pp.141-161
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• 2014

This article presents a new generation of empirical ground motion models for the prediction of response spectral accelerations in soil conditions, specifically developed for the Vrancea intermediate-depth seismic source. The strong ground motion database from which the ground motion prediction model is derived consists of over 800 horizontal components of acceleration recorded from nine Vrancea intermediate-depth seismic events as well as from other seventeen intermediate-depth earthquakes produced in other seismically active regions in the world. Among the main features of the new ground motion model are the prediction of spectral ordinates values (besides the prediction of the peak ground acceleration), the extension of the magnitudes range applicability, the use of consistent metrics (epicentral distance) for this type of seismic source, the extension of the distance range applicability to 300 km, the partition of total standard deviation in intra- and inter-event standard deviations and the use of a national strong ground motion database more than two times larger than in the previous studies. The results suggest that this model is an improvement of the previous generation of ground motion prediction models and can be properly employed in the analysis of the seismic hazard of Romania.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.270-277
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• 2019

These days, with the advent of digital broadcasting, media environment offers users an opportunity to enjoy differentiated contents in a more aggressive fashion through user-media interactions based on computer technology. In fact, the development of contents which can induce spontaneous acts from users such as outdoor ads which use certain sensors and devices and exhibition halls has been active. With the development of low-price motion recognition devices, people have been able to enjoy diverse interaction-applied media by recognizing users' motion data without body contact. In this paper, we developed an interactive media player that can recognize the user's motion and control the video in the web service environment without installing a specific program. In addition, we set user motion recognition range and developed a user motion recognition algorithm suitable for the Leap Motion equipment installed in the kiosk. The results of this study can be experienced by various interactive media such as interactive tourism, education, and movie contents in kiosks that can be installed in public places.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.675-679
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• 2018

A novel heart rate estimation algorithm is presented based on normalized least-mean-square (NLMS) algorithm. This paper presented a three-step processing scheme for estimating heart rate from PPG signal with motion artifacts. The proposed active noise cancellation algorithm has low computational complexity compared to the NLMS algorithm. Experimental results show that the proposed algorithms perform similar with the previous algorithm under motion artifact noises.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2393-2396
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• 2005

We present a method to detect on-road vehicle using geometric invariant of feature points on side planes of the vehicle. The vehicles are assumed into a set of planes and the invariant from motion information of features on the plane segments the plane from the theory that a geometric invariant value defined by five points on a plane is preserved under a projective transform. Harris corners as a salient image point are used to give motion information with the normalized correlation centered at these points. We define a probabilistic criterion to test the similarity of invariant values between sequential frames. Experimental results using images of real road scenes are presented.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.13-16
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• 1999

An active contour model, Snake, was developed as a useful segmenting and tracking tool lot rigid or non-rigid (i.e. deformable) objects by Kass in 1987 In this research, Snake is newly designed to cover this large moving case. Image flow energy is proposed to give Snake the motion information of the target object. By this image flow energy Snake's nodes can move uniformly along the direction of the target motion in spite of the existences of local minima. Furthermore, when the motion is too large to apply image flow energy to tracking, a jump mode is proposed for solving the problem. The vector used to make Snake's nodes jump to the new location can be obtained by processing the image flow. The effectiveness of the proposed Snake is confirmed by some simulations.