• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.480-485
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• 1993

A method for obtaining optimal orbital maneuvers of a space vehicle has been developed by combining feedback linearization method with the elegance of the Lambert's theorem. To obtain solutions to nonlinear orbital maneuver problems. The full nonlinear equations of motion for space vehicle in polar coordinate system are transformed exactly into a controllable linear set in Brunovsky canonical form by using feedback linearization by choosing position vector as fully observable output vector. These equations are used to pose a linear optimal tracking problem with a solutions to Lambert's problem and a linear analytical solution of continuous low thrust problem as reference trajectories.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.918-929
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• 2008

This study investigated the effects of inverted position on EEG and heart rate variability before and after Bang song gong. BSG is a training method using in qi-gong and meditation to give a convergence of consciousness on body segments in order and take a silent speech of 'song'. The subjects were the 14 university students(n=7 per group) who had not experienced any medical problem and had not practiced BSG. They took a practice of the two way of BSG training program for 30 minutes every other day for two weeks. During practicing BSG, A group took sitting position and lean sitting position by turns, B group took inverted and lean sitting position in the same way. Statistical analysis conducted by two-way ANOVA($2groups^{\ast}2periods$) with p<0.05 for average difference of EEG and HR according to position change in each group before and after BSG. In A group, EEG and HR were changeless irrespective of the change of position and BSG. On the other hand, in B group, significant changes were observed in EEG(p<0.05). ${\alpha}$ wave of inverted position were on the increase, ${\beta}$ and ${\delta}$ wave of inverted position showed smaller power after two weeks training. In the variation of HR, there were smaller variation according to the position change after BSG compared to before BSG(p<0.05). The results suggested that an inverted position may make the depth of meditation deeper, and is likely to be effective for decreasing tension of brain and the sleepiness during qi-gong training. In addition to, an inverted position seemed to promote control of blood pressure of brain. So the application of an inverted position to 'BSG' will be very helpful to achieve deeper relaxation and to obtain the desired effect from qi-gong training.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.398-404
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• 2021

This paper proposes a method of using a magnetic position sensor to detect accurately the rotor position required to perform vector control of a permanent-magnet synchronous motor, particularly the initial rotor position at startup. In the existing vector control systems, the initial rotor position was determined using the output signals of the Hall sensors, or the control was performed in a sensorless method without using such a sensor. On the other hand, the accuracy is degraded due to the occurrence of a position detection error, and the practicality was not satisfactory. This paper attempts to detect the initial rotor position using a magnetic position sensor to solve this problem. This method is used to solve the deteriorating starting characteristics of the motor in the vector control system. In addition, to lower the price of a low-power vector control inverter, this paper proposes a method of integrating the existing sensors and reducing the price to less than half using a magnetic position sensor for speed and position detection.

• Journal of the Korean Society for Nondestructive Testing
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• v.15 no.1
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• pp.299-309
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• 1995

A geometrical inverse heat conduction problem is solved for the development of Infrared Computerized-Axial-Tomography (IR CAT) Scan by using a boundary element method in conjunction with regularization procedure. In this problem, an overspecified temperature condition by infrared scanning is provided on the surface, and is used together with other conditions to solve the position of an unknown boundary (cavity). An auxiliary problem is introduced in the solution of this problem. By defining a hypothetical inner boundary for the auxiliary problem domain, the cavity is located interior to the domain and its position is determined by solving a potential problem. Boundary element method with regularization procedure is used to solve this problem, and the effects of regularization on the inverse solution method are investigated by means of numerical analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.1
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• pp.95-103
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• 2000

In this paper, a novel indirect rotor position sensing method is proposed to improve the performClIlce of sensorless drive of brushless DC motors. The fast mode change to the sensorless operation is difficult in the existing indirect rotor position sensing methods because a precise rotor position can not be obtained when an excessive input is applied to the drive during synchronous operation mode. To cope with this problem, the relationship between terminal voltage and back-emf waveform is analyzed in this paper, also a novel indirect position sensing method which can detect a precise rotor position at low speed range is proposed. The effectiveness of the proposed method is verified through the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.449-455
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• 2007

Position information is very important when driving the Permanent Magnet Synchronous Motor(PMSM). Generally, resolver is used to obtain exact position information. However, it generates periodic position errors due to the transformer ratio difference and excitation signal distortion. When the vector control is done with the position information that includes position error, torque ripple is generated from time to time. This paper proposes the solution through analysis of above problem. Also, it's validity is verified by simulation and experiment.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.29-36
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• 2005

With the rapid growth of the Internet, the Internet-based robot has been realized by connecting off-line robot to the Internet. However, because the Internet is often irregular and unreliable, the varying time delay in data transmission is a significant problem for the construction of the Internet-based robot system. Thus, this paper is concerned with the development of an Internet-based robot system, which is insensitive to the Internet time delay. For this purpose, the PPS (Position Prediction Simulator) is suggested and implemented on the system. The PPS consists of two parts : the robot position prediction part and the projective virtual scene part. In the robot position prediction part, the robot position is predicted for more accurate operation of the mobile robot, based on the time at which the user's command reaches the robot system. The projective virtual scene part shows the 3D visual information of a remote site, which is obtained through image processing and position prediction. For the verification of this proposed PPS, the robot was moved to follow the planned path under the various network traffic conditions. The simulation and experimental results showed that the path error of the robot motion could be reduced using the developed PPS.

• 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.

• Research in Community and Public Health Nursing
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• v.12 no.2
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• pp.361-374
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• 2001

This study was done to identify a status of home visiting project as a community health nursing system, that was the organization. personal who have age, educational background, marital status, position, experience of the home visiting in the public sectors in part of Seoul. Kyonggi, Kang-won area, It was done to provide basis data for the development of effective visiting nurses project in the health sectors, where was Health Centers in urban and rural. Branch of Health Center in rural and Health posts. The question airs were distributed 352 public health workers who working place was 118 health workers in 12 health centers in Seoul. 56 public health workers among 39 health center and other public health sectors in Kyonggi and 178 public health workers among health center and health care sectors. Data collected from October to December. 2000. The analysis by SAS system with F test, percentage and frequency. The major result were as follows. The general characteristics of the respondent show that most of them were graduates from community college and RN-BS with broadcast that they had not completed CPHN course but only two health workers have trained for the visiting nurses project. As for their grade in the position, the most of health workers have seventh level and the other CHP were above sixth level in the health care post that in the government structure. This indicates that workers do not have great authority in decision making, the most period of works in the position was one and two years indicating that they change jobs frequently. On an average their clinical experience was 4.11 years which is ideal for the total service. As for preparation of staff for home visiting workers education on visiting nurses program have to receive short term or longer term training course for strong emphasis. The analysis showed that public health visiting workers responds about active job performance that based on an area, approach of acting by districts, education and position are shown statistically significant difference between acceptance of the visiting nursing job show the same as well as visiting nurses project. Special concerns for visiting Nursing care spread came to burden, many of activity carry out main solution is covered the health problem connective support system needs of quality and quantity which out health problem. As 71.1% of visiting health service held on the poor population was under the guardianship of the law, but people who health insurance wide application under law shown a tendency to increase gradually. The general characteristics of the patients showed 56.2% of female on average of age was 66.1 years old, they have health problem was the most of 47.6% of high blood pressure and stroke, the other and as a problem that economics, which is complex welfare with out health problem. Community health care service should be combined health and social work program. The form of delivery of visiting health care given the most guide and education with counselling and support. (33.6%) Among the six category of visiting care service shown statistically significant difference and next is fundamental care, remedy care with priority.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.127-137
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• 2001

Low back pain is significant problem in today's society, with lifetime incidence rate reported between 50% and 90%. Many factors associated with LBP are reported. The purpose of this studies were to be evaluated static standing posture aberrations in chronic LBP in comparison with healthy individuals. The samples including 80 subjects recruited to the following two groups:patients and control(normal) Questionnaires were completed by 40 LBP patients and 40 controls at the department of Physical Therapy, Saejong neurosurgical clinic in Taegu city from October 1, 1999 to March 30, 2000. The angle of lumbar lordosis was measured on lateral x-ray films with standing position. In LBP groups. the mean degree of lumbar lordosis, sacral inclination, and lumbosacral joint angle were 29.9 ${\pm}$ 9.3, 34.8 ${\pm}$ 8.2, and 12.7 ${\pm}$ 5.7 respectively. Control groups, the mean degree of lumbar lordosis, sacral inclination and lumbosacral joint angle were 35.3 ${\pm}$ 7.8, 34.9 ${\pm}$ 6.4 and 12.5 ${\pm}$ 4.3 respectively. there were significantly decreaseds in lumbar lordosis in Low back pain group. lumbar lordosis on the working posture had significant differences among groups(sitting position patients 31.4 ${\pm}$ 9.3, standing position patients 29.4 ${\pm}$ 9.3, sitting position control 35.0 ${\pm}$ 6.4, standing position control 35.5 ${\pm}$ 8.8, respectively) (p=0.034). sacral inclination on the working posture had differences among groups(sitting position patients 35.9 ${\pm}$ 8.7.standing position patients 33.6 ${\pm}$ 7.6, sitting position control 33.9 ${\pm}$ 5.9. standing position control 35.6 ${\pm}$ 6.8, respectively). lumbersacral joint angle on the working Posture had differences among groups(sitting position patients 12.0 ${\pm}$ 5.6, standing position patients 13.4 ${\pm}$ 5.9, sitting position control 11.2 ${\pm}$ 3.0. standing position control 13.4$^{\circ}$, respectively).