• Journal of Drive and Control
• /
• v.13 no.3
• /
• pp.15-23
• /
• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.

• Progress in Medical Physics
• /
• v.25 no.2
• /
• pp.72-78
• /
• 2014

The aim of the study is to test a hypothesis that quasi-breath-hold (QBH) biofeedback improves the residual respiratory motion management in gated 3D thoracic MR imaging, reducing respiratory motion artifacts with insignificant acquisition time alteration. To test the hypothesis five healthy human subjects underwent two gated MR imaging studies based on a T2 weighted SPACE MR pulse sequence using a respiratory navigator of a 3T Siemens MRI: one under free breathing and the other under QBH biofeedback breathing. The QBH biofeedback system utilized the external marker position on the abdomen obtained with an RPM system (Real-time Position Management, Varian) to audio-visually guide a human subject for 2s breath-hold at 90% exhalation position in each respiratory cycle. The improvement in the upper liver breath-hold motion reproducibility within the gating window using the QBH biofeedback system has been assessed for a group of volunteers. We assessed the residual respiratory motion management within the gating window and respiratory motion artifacts in 3D thoracic MRI both with/without QBH biofeedback. In addition, the RMSE (root mean square error) of abdominal displacement has been investigated. The QBH biofeedback reduced the residual upper liver motion within the gating window during MR acquisitions (~6 minutes) compared to that for free breathing, resulting in the reduction of respiratory motion artifacts in lung and liver of gated 3D thoracic MR images. The abdominal motion reduction in the gated window was consistent with the residual motion reduction of the diaphragm with QBH biofeedback. Consequently, average RMSE (root mean square error) of abdominal displacement obtained from the RPM has been also reduced from 2.0 mm of free breathing to 0.7 mm of QBH biofeedback breathing over the entire cycle (67% reduction, p-value=0.02) and from 1.7 mm of free breathing to 0.7 mm of QBH biofeedback breathing in the gated window (58% reduction, p-value=0.14). The average baseline drift obtained using a linear fit was reduced from 5.5 mm/min with free breathing to 0.6 mm/min (89% reduction, p-value=0.017) with QBH biofeedback. The study demonstrated that the QBH biofeedback improved the upper liver breath-hold motion reproducibility during the gated 3D thoracic MR imaging. This system can provide clinically applicable motion management of the internal anatomy for gated medical imaging as well as gated radiotherapy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.459-464
• /
• 2004

In this paper, an autonomous navigation system for autonomous guided vehicles (AGVs) operated in an automated container terminal is designed. The navigation system is based on the sensors detecting the range and bearing. The navigation algorithm used is an interacting multiple model (IMM) algorithm to detect other AGVs and avoid other obstacles using informations obtained from multiple sensors. As models to detect other AGVs (or obstacles), two kinematic models are derived： Constant velocity model for linear motion and constant speed turn model for curvilinear motion. For constant speed turn model, an unscented Kalman filter (UKF) is used because of drawbacks of the extended Kalman filter (EKF) in nonlinear system. The suggested algorithm reduces the root mean squares error for linear motions, while it can rapidly detect possible turning motions.

• Language and Information
• /
• v.20 no.1
• /
• pp.73-91
• /
• 2016

Korean adjectives in general cannot combine with measure phrases (MP), but MPs are compatible with adjectives when they appear with the inchoative morpheme -(e)ci. In this case, MPs can only denote the difference between two states along the dimension denoted by the root adjective. To account for this, this paper proposes that i) -(e)ci is a spell-out of V in the directed motion construction which takes an abstract path argument, like become, and ii) this path argument contains a comparative morpheme. By assuming this we can explain why MPs appear with -(e)ci, as well as other interesting phenomena such as variable telicity in deadjectival verbs with -(e)ci.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.10a
• /
• pp.233-240
• /
• 1999

A general procedure is presented here to develope seismic design and analysis method for cable-supported bridges like suspension bridges subjected to ground motion. For representing a numerical model of suspension bridges. a new approach which satisfy design conditions for the initial equilibrium state of suspension bridges. without any nonlinear iterations. is proposed. The dynamic behavior of that model is verified by free vibration analysis. This study uses the response spectrum analysis to determine the Peak response of a suspension bridge to earthquake-induced ground motion. The SRSS(Square Root of Sum of Square). modal combination rule, is adopted for each direction, longitudinal and transverse. To illustrate the potential applicability for the seismic design of suspension bridges, a numerical example is presented in which the dynamic response of the Nam-hae suspension bridge subjected to earthquake

• Aerospace Engineering and Technology
• /
• v.13 no.2
• /
• pp.66-72
• /
• 2014

This paper introduces an asynchronous multiple radar fusion algorithm for space object tracking. To estimate orbital motion of space object, a multiple radar scenario which jointly measures single object with different sampling time indices is described. STK/ODTK is utilized to determine realization of orbital motion and joint coverage of multiple radars. Then, asynchronous fusion algorithm is adapted to enhance the estimation performance of orbital motion during which multiple radars measure the same time instances. Monte-Carlo simulation results demonstrate that the proposed asynchronous multi-sensor fusion scheme better than single linearized Kalman filter in an aspect of root mean square error.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.2
• /
• pp.858-864
• /
• 2017

This study aims to restrain free conducting wire-type particles which are commonly and dangerously existing within DC gas-insulated transmission lines. A realistic platform of a coaxial cylindrical electrode was established by using a high-speed camera and a partial discharge (PD) monitor to observe the motion, PD, and breakdown of these particles. The probabilities of standing or bouncing, which can be affected by the length of the particles, were also quantitatively examined. The corona images of the particles were recorded, and particle-triggered PD signals were monitored and extracted. Breakdown images were also obtained. The air-gap breakdown with the particles was subjected to mechanism analysis on the basis of stream theory. Results reveal that the lifting voltage of the wire particles is almost irrelevant to their length but is proportional to the square root of their radius. Short particles correspond to high bouncing probability. The intensity and frequency of PD and the micro-discharge gap increase as the length of the particles increases. The breakdown voltage decreases as the length of the particles decreases.

• Journal of Pharmaceutical Investigation
• /
• v.9 no.3
• /
• pp.22-26
• /
• 1979

This report was carried out toxicity test for the mosquito coil made of Ginseng leaf and the residue after extraction of Ginseng root. This results are as follows: In the first group, was not shown any special difference on the body weight, the motion and dissection. In the second group, was not shown any Special difference on the body weight, considerable difference on the motion and considerable loss of appetite besides very slight loss, but came cack soon again to normal state by change of air after a moment. In the third group, the body weight and appetite was depressed very slightly and the motion was shown very slightly difference, but came back soon again to normal state by chenge of air after a moment too. No one was died, and all the animal were the normal state on the reslt of dessection, Therefore, we have positive evidence that this mosquito coil powder is applied to animals without any toxicity.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.485-492
• /
• 1990

This paper propose a optimal design method for robust notion controllers of under-water vehicles using the combined technique between classical and modern theories. The proposed method is presented which utilizes classical control methods to obtain a good robustness and modern control methods to set optimal gains. LQ, SVD, multivariable frequency analysis and Bode-Root Locus (BRL) plot are used.

• Progress in Medical Physics
• /
• v.23 no.2
• /
• pp.91-98
• /
• 2012

Verification of internal organ motion during treatment and its feedback is essential to accurate dose delivery to the moving target. We developed an offline based internal organ motion verification system (IMVS) using cine EPID images and evaluated its accuracy and availability through phantom study. For verification of organ motion using live cine EPID images, a pattern matching algorithm using an internal surrogate, which is very distinguishable and represents organ motion in the treatment field, like diaphragm, was employed in the self-developed analysis software. For the system performance test, we developed a linear motion phantom, which consists of a human body shaped phantom with a fake tumor in the lung, linear motion cart, and control software. The phantom was operated with a motion of 2 cm at 4 sec per cycle and cine EPID images were obtained at a rate of 3.3 and 6.6 frames per sec (2 MU/frame) with $1,024{\times}768$ pixel counts in a linear accelerator (10 MVX). Organ motion of the target was tracked using self-developed analysis software. Results were compared with planned data of the motion phantom and data from the video image based tracking system (RPM, Varian, USA) using an external surrogate in order to evaluate its accuracy. For quantitative analysis, we analyzed correlation between two data sets in terms of average cycle (peak to peak), amplitude, and pattern (RMS, root mean square) of motion. Averages for the cycle of motion from IMVS and RPM system were $3.98{\pm}0.11$ (IMVS 3.3 fps), $4.005{\pm}0.001$ (IMVS 6.6 fps), and $3.95{\pm}0.02$ (RPM), respectively, and showed good agreement on real value (4 sec/cycle). Average of the amplitude of motion tracked by our system showed $1.85{\pm}0.02$ cm (3.3 fps) and $1.94{\pm}0.02$ cm (6.6 fps) as showed a slightly different value, 0.15 (7.5% error) and 0.06 (3% error) cm, respectively, compared with the actual value (2 cm), due to time resolution for image acquisition. In analysis of pattern of motion, the value of the RMS from the cine EPID image in 3.3 fps (0.1044) grew slightly compared with data from 6.6 fps (0.0480). The organ motion verification system using sequential cine EPID images with an internal surrogate showed good representation of its motion within 3% error in a preliminary phantom study. The system can be implemented for clinical purposes, which include organ motion verification during treatment, compared with 4D treatment planning data, and its feedback for accurate dose delivery to the moving target.