• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.5
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• pp.361-368
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• 2010

This paper presents high speed position controller using stepping motor. The proposed position controller has close loop and open loop mode. In the high speed region, torque angle which is controlled by PI controller and memory based look-up table, is used to keep the reference position. The memory based look-up table produces a torque angle according to motor speed, and the PI controller can compensate the torque angle error. So, the fast dynamic response can be expected in the same position error. The open loop control mode which is divided by 3-modes control the actual position in the low speed and small position error. Each open loop modes are designed to reduce position error and dynamic brake in the stop command. The proposed position control scheme is verified by the practical stepping motor.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.37-48
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• 2017

Purpose: The most basic conditions of radiation therapy is to prevent unnecessary exposure of normal tissue. The risk factors that are important o evaluate the dose emitted to the lung and heart from radiation therapy for breast cancer. Therefore, comparing the dose factors of a normal tissue according to the radion treatment position and Seeking an effective radiation treatment for breast cancer through the analysis of the correlation relationship. Materials and Methods: Computed tomography was conducted among 30 patients with left breast cancer in supine and prone position. Eclipse Treatment Planning System (Ver.11) was established by computerized treatment planning. Using the DVH compared the incident dose to normal tissue by position. Based on the result, Using the SPSS (ver.18) analyzed the dose in each normal tissue factors and Through the correlation analysis between variables, independent sample test examined the association. Finally The HI, CI value were compared Using the MIRADA RTx (ver. ad 1.6) in the supine, prone position Results: The results of computerized treatment planning of breast cancer in the supine position were V20, $16.5{\pm}2.6%$ and V30, $13.8{\pm}2.2%$ and Mean dose, $779.1{\pm}135.9cGy$ (absolute value). In the prone position it showed in the order $3.1{\pm}2.2%$, $1.8{\pm}1.7%$, $241.4{\pm}138.3cGy$. The prone position showed overall a lower dose. The average radiation dose 537.7 cGy less was exposured. In the case of heart, it showed that V30, $8.1{\pm}2.6%$ and $5.1{\pm}2.5%$, Mean dose, $594.9{\pm}225.3$ and $408{\pm}183.6cGy$ in the order supine, prone position. Results of statistical analysis, Cronbach's Alpha value of reliability analysis index is 0.563. The results of the correlation analysis between variables, position and dose factors of lung is about 0.89 or more, Which means a high correlation. For the heart, on the other hand it is less correlated to V30 (0.488), mean dose (0.418). Finally The results of independent samples t-test, position and dose factors of lung and heart were significantly higher in both the confidence level of 99 %. Conclusion: Radiation therapy is currently being developed state-of-the-art linear accelerator and a variety of treatment plan technology. The basic premise of the development think normal tissue protection around PTV. Of course, if you treat a breast cancer patient is in the prone position it take a lot of time and reproducibility of set-up problems. Nevertheless, As shown in the experiment results it is possible to reduce the dose to enter the lungs and the heart from the prone position. In conclusion, if a sufficient treatment time in the prone position and place correct confirmation will be more effective when the radiation treatment to patient.

• Phonetics and Speech Sciences
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• v.10 no.1
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• pp.23-31
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• 2018

In this study, we examined how the upper and lower lips articulate to produce labial /p/. Using electromagnetic midsagittal articulography, we collected flesh-point tracking movement data from eight native speakers of Seoul Korean (five females and three males). Individual articulatory movements in /p/ were examined in terms of minimum vertical upper lip position, maximum vertical lower lip position, and corresponding vertical upper lip position aligned with maximum vertical lower lip position. Using linear mixed-effect models, we tested two factors (word boundary [across-word vs. within-word] and speech rate [comfortable vs. fast]) and their interaction, considering subjects as random effects. The results are summarized as follows. First, maximum lower lip position varied with different word boundaries and speech rates, but no interaction was detected. In particular, maximum lower lip position was lower (e.g., less constricted or more reduced) in fast rate condition and across-word boundary condition. Second, minimum lower lip position, as well as lower lip position, measured at the time of maximum lower lip position only varied with different word boundaries, showing that they were consistently lower in across-word condition. We provide further empirical evidence of lower lip movement sensitive to both different word boundaries (e.g., linguistic factor) and speech rates (e.g., paralinguistic factor); this supports the traditional idea that the lower lip is an actively moving articulator. The sensitivity of upper lip movement is also observed with different word boundaries; this counters the traditional idea that the upper lip is the target area, which presupposes immobility. Taken together, the lip aperture gesture is a good indicator that takes into account upper and lower lip vertical movements, compared to the traditional approach that distinguishes a movable articulator from target place. Respective of different speech rates, the results of the present study patterned with cross-linguistic lenition-related allophonic variation, which is known to be more sensitive to fast rate.

• The Journal of Korean Physical Therapy
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• v.24 no.6
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• pp.414-418
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• 2012

Purpose: Muscle fatigue affects proprioception, and it causes problems in spinal stability. The purpose of this study was to examine the effect on the accuracy of reproducing the lumbar angles before lumbar exercise and after fatiguing isokinetic lumbar exercise. Methods: Thirty healthy adults participated in this study. Before induction of fatigue by exercise, the proprioception was measured by Biodex. Lumbar positions were passively maintained on stimulation position ($25^{\circ}$ flexion and $25^{\circ}$ extension), and back to the starting position. Subjects actively repositioned the remembered stimulation position, and error degrees between the stimulation position and reposition were measured. Using an isokinetic device at $120^{\circ}$/sec of velocity of angle lumbar flexion/extension exercise resulted in muscle fatigue. The post-fatigue proprioceptive position sense was used in the same way as in pre-fatigue measurement. Results: Means of position sense of pre-fatigue were $2.19{\pm}1.97$ on flexion angle, and $5.04{\pm}2.84$ on extension angle. After exercise induced fatigue, means of position sense were $2.37{\pm}1.83$ on flexion angle, and $4.93{\pm}2.57$ on extension angle. Results of this study showed significant differences of lumbar proprioceptive position sense between pre- and post-fatigue. Conclusion: Lumbar proprioception sense in active repositioning in flexion and extension was affected in the presence of muscle fatigue. Therefore, it should be noted that therapeutic exercise for patients with abnormal proprioceptive sense or elderly people must be performed with care because muscle fatigue can cause secondary damage.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.329-338
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• 1998

The authors examined the condylar position and shape of condylar process from the transcranial radiographs and polytomographs of the 130 temporomandibular joints of 65 patients who complained symptoms of temporomandibular disorder and the followings were obtained; 1. The age and sex distribution of the 65 patients showed peak incidence in 2nd decade (27.7％) followed by 3rd (18.5％) and 4th decade (18.5％) and female predominance (87.7％). 2. In polytomography 64 joints (49.2％) showed consistent condylar position from lateral to medial and 39 joints (30.0％) of them showed agreement with those of transcranial radiographs. Among the 66 joints (50.8％) which showed changes in condylar position. 48 joints (36.9％) showed agreement with lateral and central tomographic and transcranial radiographic position. 41 joints (31.5％) showed disagreement in condylar position between the polytomographic and transcranial radiographic images. 3. When the condylar position was classified as anterior, central and posterior. the posterior position was the most frequent position, that is . 42.3％ of the transcranial radiography and 42.3％.49.2％ and 38.5％ of the lateral, central and medial polytomographic radiographs. 4. In polytomography 84 joints (64.6％) showed consistent condylar shape from lateral to medial and 74 joints (56.9％) of them showed agreement with those of transcranial radiographs. Among the 46 joints (35.4％) which showed changes in condylar shape. 40 joints (30.1％) showed agreement with lateral and central tomographic and transcranial radiographic shape. 41 joints (31.5％) showed disagreement in condylar shape between the polytomographic and transcranial radiographic images.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.179-189
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• 2017

This paper is the fifth investigation on the methods of evaluating flow characteristics in a steady flow bench. In previous studies, several assumptions used in the steady flow bench were examined and it was concluded that the assumption of the solid rotation may lead to serious problems. In addition, though the velocity profiles were improved as the measuring position went downstream, the distributions were far from ideal regardless of the valve angle and evaluation position. The eccentricities were also not sufficiently small to disregard the effect on impulse swirl meter (ISM) measurement. Therefore, the effect of these distribution and eccentricity changes according to the positions needs to be analyzed to discuss the method of flow characteristics estimation. In this context, the effects of evaluation position on the steady flow characteristics were studied. For this purpose, the swirl coefficient and swirl ratio were assessed and compared via measurement of the conventional ISM and calculation based on the velocity by particle image velocimetry(PIV) from 1.75B, 1.75 times bore position apart from the cylinder head, to the 6.00B position. The results show that the swirl coefficients by ISM strictly decrease and the curves as a function of the valve lift become smooth and linear as the measuring position goes downstream. However, the values through the calculation based on the PIV are higher at the farther position due to the approach of the tangential velocity profile to ideal. In addition, there exists an offset effect between the velocity distribution and eccentricity in the low valve lift range when the coefficients are estimated based on the swirl center. Finally, the curve of the swirl ratio by ISM and by PIV evaluation as a function the measuring position intersect around 5.00B plane except at $26^{\circ}$ valve angle.

• Physical Therapy Korea
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• v.8 no.2
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• pp.1-16
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• 2001

This study was designed to identify the effects of foot position on electromyographic (EMG) activity of the quadriceps femoris during maximum voluntary contraction (MVC) in standing. Twenty young adults who had not experienced any knee injuries were recruited. Their Q-angles were within a normal range. They were asked to stand in five different foot positions ($40^{\circ}$ externally rotated, $30^{\circ}$ internally rotated, neutral, $20^{\circ}$ plantarflexed, and $10^{\circ}$ dorsiflexed foot position). The EMG activities of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis oblique (VMO) were recorded in standing by surface electrodes and normalized by MVC EMG values derived from manual muscle test. The normalized EMG activity levels (%MVC EMG) of muscles in the five foot positions were compared using repeated measures ANOVA. The EMG activity levels of the VL, RF, and VMO were the highest when foot was externally rotated. The EMG activity levels of the VL and RF were significantly different among the foot positions (p<.05). However, EMG activity levels of the VL, RF, VMO, and VMO/VL ratio did not show significant differences in each foot position (p> .05). The results suggest that the quadriceps femoris may be effectively activated by performing MVC at an externally rotated foot position. Therefore, the externally rotated foot position can be considered as an effective foot position for quadriceps femoris strengthening exercise. Further studies are needed to identify whether there are differences in the effects of foot position on muscle strength after MVC exercise of quadriceps femoris in standing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.3
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• pp.232-239
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• 2008

The position sensors used in a magnetic bearing system are desirable to provide some degree of fault-tolerance as the rotor position is necessary for the feedback control to overcome the open-loop instability. In this paper, we propose an inductive position sensor that can cope with a partial fault in the sensor. The sensor has multiple poles which can be combined to sense the in-plane motion of the rotor. When a high-frequency voltage signal drives each pole of the sensor, the resulting current in the sensor coil contains information regarding the rotor position. The signal processing circuit of the sensor extracts this position information. In this paper, we used the magnetic circuit model of the sensor that shows the analytical relationship between the sensor output and the rotor motion. The multi-polar structure of the sensor makes it possible to introduce redundancy which can be exploited for fault-tolerant operation. The proposed sensor is applied to a magnetically levitated turbo-molecular vacuum pump. Experimental results validate the fault-tolerance algorithm.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1678-1684
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• 2007

Platform Screen Door(PSD) has been installed in train manual operation section(ATS/ATC) by SeoulMetro since 2005. PSDs are now operating at 17 stations in SeoulMetro lines. As a result, it increases the safety of passenger, makes a comfortable platform and saves the energy of air conditioning. For PSD operation, train shall stop within 600mm of the train stop reference point. In train manual operation section, the detection system of train position is required to notify the train driver of train position and to ensure the condition that train stops the correct position for PSD operation. To detect the train stop position, the optical sensor shall be installed at platform. However, in case of SeoulMetro lines, the detection criterions of the train correct position stop are different because of using various types of trains which have different size and shape of front cars. In this paper, to solve this problem, the precise detection algorithm of the train stop at the correct position is used, and Laser distance measure sensor is introduced to notify the distance form the reference point of the train correct stop to train driver. This system has been applying to Seoul Metro line total.

• Journal of Korean Clinical Nursing Research
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• v.16 no.1
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• pp.5-15
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• 2010

Purpose: The purpose of this study was to examine the effect of position change on the level of comfort and occurrence of bleeding after transarterial chemoembolization. Methods: This study was the nonequivalent control group non-synchronized design. The experimental group was positioned in supine with 15-30 degree Semi-folwer's position for 2 hours and then changed supine position alternatively to 30 degree lateral positioning in turn per hour for 2 hours. For the control group, 6 hour supine positions without any position change were applied. Results: The level of discomfort of the control group was scored higher level than that of the experimental group. There was no significant differences in back pain and the degrees of voiding difficulty. There were no significant differences in the incidence of bleeding complication between the two groups. Conclusion: The position change in patients after transarterial chemoembolization could be applied without any severe side effects such as bleeding complication, but it was revealed to be effective in reducing the level of discomfort.