• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.4-6
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• 2003

We have developed the active matrix OLED displays with a high efficiency red emission material which uses an emitting assist (EA) dopant system. The EA dopant (rubrene) did not itself emit but assisted the energy transfer from the host ($Alq_s$) to the red emitting dopant(DCM2). A stable red emission (chromaticity coordinates: x=0.64, y=0.36) was obtained in this cell within the luminance range of 100 - 4000 $cd/m^2$ By using EA dopant system, we can realize the reduction of the power consumption of the OLED display..

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.143-150
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• 2023

As Korea's per capita income increases, participation in various leisure activities to improve the quality of life of the disabled is encouraged. However, in order to participate in leisure activities, movement to the place where the leisure activities are performed must be preceded, so interest in means of transportation for leisure activities of the disabled is increasing. Since manual and electric wheelchairs have their respective disadvantages as means of transportation for leisure activities, interest in power assisting devices for wheelchairs combining the functions of electric wheelchairs with manual wheelchairs is increasing. In this study, the FDA approval process of wheelchair power-assistance products was investigated, and the characteristics of side-attached, front-attached, downward-attached, and rear-attached types of power assist devices for wheelchairs wheelchair in countries around the world were identified. These information will be of great use in helping the disabled and their assistants in Korea to choose the optimal product according to the patient's condition. More usability tests and clinical case studies are needed so that people with disabilities can choose a power assist device suitable for them.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.163-173
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• 2021

In the era of digital transformation, the transportation underprivileged remains as an underprivileged class without the benefits of technological advances. Electric assist devices for the People with disability are inadequate to provide services suitable for the current traffic environment, although the mobility of the People with disability is improved. In this paper, we develop IoT smart mobility by deriving essential elements through user satisfaction surveys to efficiently move physical distances based on the experience of users using existing electric assistive devices. Based on the data collected through user satisfaction survey, quantitative analysis using TF-IFD and qualitative analysis based on QFD are performed to determine the importance of user requirements. For the evaluation of IoT smart mobility design results reflecting essential functions, usability verification is conducted by forming an expert evaluation team in various fields. In the future, we plan to conduct a service design study that can improve mobility convenience and provide mobility service solutions by designing to provide efficient public services by utilizing IoT smart mobility to the People with disability.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.525-531
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• 2023

In Korea, which is entering a super-aged society, the number of elderly patients who have difficulty walking independently is expected to increase rapidly, and it is necessary to develop wheelchair products with various functions to improve the quality of life of people with walking disabilities. Recently, wheelchair power assist devices that provide propulsion power by being attached to a manual wheelchair has been developed and is entering the domestic and global markets. In this study, we compared and analyzed the process of obtaining medical device certification for wheelchair power assist devices in Korea, the United States, and Europe. In Korea, a Class 2 medical device certification process was developed in 2021, and in the US FDA, it corresponds to Class 2 like the existing electric wheelchair and must pass the 510k certification process. In the case of Europe, it is uniquely regulated as Class I, and the CE mark can be attached through a relatively easy self-declaration of conformity. The Korean medical device industry, which is struggling with MDR certification, a new European medical device regulation, should pay attention to the relatively easy entry into the global market for wheelchair power assist products.

• Journal of Power Electronics
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• v.16 no.2
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• pp.798-804
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• 2016

This paper proposes a new operation and control strategy for Power-Assisted Wheelchairs (PAW) using one brushless DC (BLDC) motor. The conventional electrical wheelchairs are too heavy and large for one person to move because they have two electric motor wheels. On the other hand, the proposed PAW system has a small volume and is easy to move due to the presence of a single wheel motor. Unlike the conventional electric wheelchairs, this structure for a PAW does not have a control joystick to reduce its weight and volume. To control the wheelchair without a joystick, a special control system and algorithm are needed for proper operation of the wheelchair. In the proposed PAW system uses only one sensor to detect the acceleration and direction of PAW's movement. By using this sensor, speed control can be achieved. With a speed control system, there are three kinds of operations that can be done on the speed of a PAW: the increment of PAW speed by summing external force, the decrement of PAW speed by subtracting external force, and emergency breaking by evaluating the time duration of external force. The validity of the proposed algorithm is verified through experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.81-87
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• 1998

This paper provides an investigation of torque transmission system using ERF (Electro-Rheological Fluid). The torque transmission system using ERF is a new conception device because an apparent viscosity of ERF can be changed by applying an electric field, We use the coaxial cylinder type in which the ERF fills the annular space between a pair of coaxial cylindrical electrodes and experiment results show that the measured torque was increased with the increase of the electric field. These are analyzed to provide guidelines to assist in the development of practical ER devices.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.516-518
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• 2000

This paper presents a methodology for effective control of fuel cell devices connected to the electric utility distribution network. A controller is designed for a fuel cell power plant to assist the conventional generators to damp out oscillations, which is possible by utilizing the fast response characteristic of fuel cells. Computer model of the controller is proposed and its effectiveness is proved by a sample test. Fuel cell devices can be used to improve power system stability when these are connected to a distribution system.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.86-108
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• 2012

$CO_2$ reduction, energy security, and emission reduction are the critical issues in the current automotive industry. As one of the solutions to these issues, Battery Electric Vehicle is attracting attention recently. Advanced battery electric drive vehicle require batteries, power electronics and electrical machines to function. These devices allow the vehicle to use energy from the battery to assist in the propulsion of the vehicle. In this paper, the main feature of these technologies are briefly introduced and recent trends of patent applications are described.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.405-411
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• 2022

Korea's long-term care insurance for the elderly, which started in 2008, is a borrowed one from gaeho insurance, which started eight years earlier. Both countries have a policy of welfare equipment benefit systems to support the lives of the elderly who are intellectually and mentally weakened. In this study, we attempted to compare and examine the welfare equipment items in Korea with those in Japan and find out the characteristics of the items in Korea and Japan. In Korea, loitering-detection device, posture changing devices, and incontinence underwears were registered as welfare devices before Japan, and in Japan, automatic urine disposal systems, wheelchair electric assist device, position converters, and lifts for handicapped person were designated as welfare devices before Korea. In addition, the Japanese Ministry of Health, Labor and Welfare has announced the designation of the excretion prediction support device as a welfare device. If Korea and Japan cooperate to develop welfare equipment items together, it will be of great help in improving the quality of life of the elderly in both countries in a super-aged society.

• International Journal of Fluid Machinery and Systems
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• v.4 no.3
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• pp.317-323
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• 2011

Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices and so on. Further, the needs for mini centrifugal pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini centrifugal pump design be as simple as possible as precise manufacturing is required. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, we started research on the mini centrifugal pump for the purpose of development of high performance mini centrifugal pumps with simple structure. Three types of rotors with different outlet angles are prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on performance and internal flow condition of mini centrifugal pumps. In addition to that, the blade thickness is changed because blockage effect in the mini centrifugal pump becomes relatively larger than that of conventional pumps. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-Fluent) to investigate the internal flow condition. It is clarified from the experimental results that head of the mini centrifugal pump increases according to the increase of the blade outlet angle and the decrease of the blade thickness. In the present paper, the performance of the mini centrifugal pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle and the blade thickness on the performance are investigated and the internal flow of each type of rotor is clarified by the numerical analysis results.