• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.685-688
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• 2006

A single-phase uninterruptible power supply system suitable for a SMES unit is proposed to achieve a simple circuit configuration and higher system reliability. It reduces the number of switching devices by applying a common-arm scheme. Operational principles to normal, stored-energy, and bypass mode are discussed in detail. Eliminating some of the switches or substituting passive components for active switches generally increases the sophistication and reduces degree of freedom in control strategy. However, the high-performance digital controller ran execute the complicated control task with no additional cost. The validity of the proposed UPS system will be verified by a computer-aided simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.689-694
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• 2004

To increase accurateness and reliability of the evaluation of power tool vibration transmitted to an operator, it is necessary to measure grip and feed forces during the measurement of hand-transmitted vibration. In the study a system was invented to measure the vibration and the grip and/or feed force, which consists of a measurement handle and a PC with data acquisition system and the software. Strain gauges and an accelerometer were mounted on the handle for the simultaneous measurement of the forces and the vibration. The program in the system makes it possible to monitor the grip and feed force during the tool operation so that the operator keeps the applying forces within the pre-determined range. Investigating the vibration total values, frequency-weighted root mean square accelerations at the handle, obtained at various conditions with control of the grip and feed force showed more consistency than those measured without force control. By using the system the experimenter can reduce uncertainty of the measured vibration.

• Journal of Nutrition and Health
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• v.27 no.3
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• pp.281-291
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• 1994

The purpose of this study was to investigate the effectiveness of enteral nutritional support to cancer patients who were clinically malnourished and receiving chemotherapy after surgery. To estimate the effect of nutritional support using Greenbia(Dr. Chung's Food Cooperation, LTD., Seoul, Korea) for patients with cancer, 41 patients were participated between January 1991 to November 1991. All patients were randomized into 2 groups and 18 patients were evaluated(experimental group : 12, control group : 6). The counseling was carried out once a week for 2 months. To compare the nutrient intake before and after administration of nutritional beverage and to identify the potential effectiveness of nutritional support in this group, a record of this diet on all patients during the test period was carried out for 3 days. To evaluate the patients nutritional status, the anthropometric parameters and serum protein were checked at the begining as baseline, week 3, week 6, and at the end of the test(week 8). In the case of energy balance, no patients appeared to be positive before administration of nutritional beverage, while 2 patients among 12 were observed to be more than 100% positive after administration. There were some differences among the experimental group which had administration of nutritional beverage but most of the results of anthropometric parameters were improved. When comparing the experimental and control group, there was significant increase in body weight, body fat, arm circumference and tricep skinfold. This study suggests that enteral nutritional support can help improving the nutritional status of patients received chemotherapy.

• Annals of Rehabilitation Medicine
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• v.42 no.6
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• pp.854-862
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• 2018

Objective To investigate the effect of treadmill training with eyes open (TEO) and closed (TEC) on the knee joint position sense (JPS), functional balance and mobility in children with spastic diplegia. Methods Forty-five children with spastic diplegia aged 11-13 years participated in this study. They were randomly assigned to three groups of equal number. The control group (CON) underwent designed physical therapy program whereas, the study groups (TEO and TEC) underwent the same program, in addition to treadmill gait training with eyes open and closed, respectively. Outcome measures were the degree of knee joint position error, functional balance and mobility. Measurements were taken before and after 12 weeks of intervention. Results After training, the three groups showed statistically significant improvement in all measured outcomes, compared to the baseline with non-significant change in the knee JPS in the CON group. When comparing posttreatment results, the TEC group showed greater significant improvement in all measured outcomes, than the TEO and CON groups. Conclusion Treadmill training with eyes open and closed is effective in rehabilitation of children with diplegia, but blocked vision treadmill training has more beneficial effect.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.1-7
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• 2022

Robots are widely used in industries and services. Traditional robots have been used to perform repetitive tasks in a fixed environment, and it is very difficult to solve a problem in which the physical interaction of the surrounding environment or other objects is complicated with the existing control method. Reinforcement learning has been actively studied as a method of machine learning to solve such problems, and provides answers to problems that robots have not solved in the conventional way. Studies on the learning of all physical robots are commonly affected by noise. Complex noises, such as control errors of robots, limitations in performance of measurement equipment, and complexity of physical interactions with surrounding environments and objects, can act as factors that degrade learning. A learning method that works well in a virtual environment may not very effective in a real robot. Therefore, this paper proposes a weighted sum method and a linear regression method as an effective and accurate learning method in a noisy environment. In addition, the bottle flipping was trained on a robot and compared with the existing learning method, the validity of the proposed method was verified.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.65-72
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• 2023

PURPOSE: This study assessed the influence of bilateral coordination exercises on unstable support surfaces on leg muscle activation and balance in stroke patients. METHODS: Two groups were recruited for comparison: an experimental group of 10 individuals who performed bilateral coordination exercises on unstable surfaces and a control group of 10 individuals who performed the same exercises on stable surfaces. All participants were assigned randomly. Pre-tests were conducted to measure the leg muscle activation and balance levels of the participants prior to the experiment. The intervention was comprised of three 30-minute weekly sessions for four weeks, followed by a post-test after the four-week period. RESULTS: Significant differences were identified within the experimental group in relation to all muscles (p < .01) and balance (p < .05). Within the control group, significant differences were identified in relation to the rectus femoris muscle, biceps femoris muscle, and balance (p < .05). Significant differences between the two groups were only observed in relation to the tibialis anterior and soleus muscles (p < .05). CONCLUSION: Only the tibialis anterior and soleus muscles showed significant differences between the two groups. This effectiveness may be attributed to using an ankle strategy to maintain body balance during exercise on unstable surfaces.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.104-111
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• 1998

This study solves the inverse kinematics problem of industrial FANUC robot. Because every joint angle of FANUC robot is dependent on the position of end-effector and the direction of approach vector, arm metrix T6 is very complicated and each joint angle is a function of other joint angles. Therefore, the inverse kinematics problem can not be solved by conventional methods. Noticing the fact that if one joint angle is known, the other joint angles are calculated by the algebraic methods. $ heta$1 is calculated using neumerical analysis method, and solves inverse kinematics problem. This proposed method, in this study, is more simpler and faster than conventional methods and is very useful in the real-time control of the manipulator.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.79-80
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• 2008

본 논문은 FPGA 기반에서 실수형 프로세서의 설계 및 구현에 대한 내용과 이를 이용하여 휴머노이드 로봇 팔의 위치제어를 위한 PD 제어기반의 신경회로망 제어기의 구현에 대한 내용이다. 설계된 프로세서는 명령어 기반의 처리를 통해 산술 연산 뿐만 아니라 로봇의 제어에 사용되는 외부 모듈의 사용이 가능하도록 설계하였으며, 신경회로망 구현에 사용되는 지수함수를 효율적으로 근사화하기 위한 Taylor series를 이용한 알고리즘을 하드웨어 레벨에서 구현하였다. 휴머노이드 로봇 팔의 위치 추종을 위해 고전적인 PD 제어기를 설계하고 PD 기반의 신경회로망 제어기를 설계하였다. 로봇 팔의 6축 제어를 위한 신경회로망 제어기에 요구되는 많은 연산을 감당하도록 하기 위해 설계된 프로세서를 통해 정의된 프로그래밍언어로 제어 프로그램을 작성하였다. PD 제어기와 PD 기반의 신경회로망 제어기를 하드웨어에 설계하여 로봇팔의 위치 추종을 실험하였으며 성능을 비교 검증하였다. 프로세서는 Altera의 Stratix II EP2S180 DSP development board에 구현되었으며 실험적으로 25MIPS의 성능을 가지는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.247-250
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• 1996

In this paper, we have examined the impedance characteristics of a tipper link of human being in a positioning motion. Firstly, we have shown the characteristics of the human arm using a bilinear model. From the bilinear model, we have observed that both the driving torque of the forearm and the visco-elasticity of the elbow joint can be controlled by muscles, respectively. Then, we have defined several indexes to show the impedance characteristics. Using the proposed indexes, we have examined the impedance characteristics in the positioning operation. As a result, we can not observe the difference of the impedance characteristics, even if the ease of the positioning motion is varied.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1621-1623
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• 1997

Use of teaching pendant is the most widespread and economical way to teach desired motion to robots. It is also very primitive,time consuming and ineffective way of teaching which has not changed since the early days of robot. In order to reduce the teaching effor, a new efficient form of teaching is needed. Also, the recent robotics research trend into service robots such as home robot, nurse robot and medical robot calls for a new teaching method which is both easy and inexpensive. In this paper, the design and operation principle of a low cost force/moment sensor is presented. The proposed sensor architecture is so simple and inexpensive that it opens the prospect for a new paradigm of robot teaching which is easy and efficinet. Other prospective areas of application are tele-manipulation of robots wher it can be used in master arm, and virtual environment where it can be used as an user input device.