• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.349-352
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• 2003

A personal low-frequency stimulator is a portable device to relax muscle pains of a person. The stimulator generates combined low-frequency pulses to be applied to pads attached to painful muscles. This paper reports a development of such device with its characteristic analyses. The major components of our stimulator are MCU, high-voltage generating circuit part, high-voltage switching circuit part, input switch part and display unit. High-voltage generating circuit is designed by using a boost converter circuit and allows user control of the output voltage. High-voltage switching circuit, controlled by MCU, generates output voltage to be applied to pads. Input switch part is composed of power supply, intensity selection, mode selection and memory. Display unit adopts a text LCD module to display modes, Intensity, output frequency and user set-up time. Our designed safety circuit, to protect human body from possible electric shock, slowly increases the output voltage to the selected output intensity. It continuously checks the output pulse shape and disable the output when dangerous pulses are detected. This paper also shows some experimental results.

• Cross-Cultural Studies
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• v.39
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• pp.83-95
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• 2015

Every country has a dark history in the process of transition to a modern state. Many countries have until the 21st century, especially in East Asia, colonialism, has experienced conflict influenced, racial discrimination, the trauma of such massacre. Such a dark history in many countries are also still in progress. Dark History of China, which maintains the proletarian dictatorship is the 'Cultural Revolution(Wenhua da Geming)'. 'Cultural Revolution' is neither the outer aspect of the ideological struggle, but in fact it was not even class struggle ideology and class struggle. Put an end to the feudal intellectuals in China in the course of the tragedy stood and lead to build a new China suffered the humiliation of being betrayed from state power. Chinese writers after the 'Cultural Revolution' ended, was created in the process of creation reflects the tragedy of the 'Cultural Revolution' in the country(national memory) is suffering from the pain and suffering the same growth process as it saw this novel growth experienced in the personal growth process. "Road leaving at 18 years" of WiHua has ruled out the pain of growing national attention wholly to personal growth and pain. Such "Road leaving at 18 years" in the sense suggests the possibility of a typical growth story in China Contemporary Literature.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.362-371
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• 2020

Purpose: The following study seeks to ascertain the motivations behind students' academic major selection and to identify the obstacles they encounter in the transition to university life, with the objective of providing information necessary to adapt well to the university and the course. Thereby, we aim to supply basic resources needed in the development of a university adaptation program to prevent academic dropout. Methods: Between October 1, 2019 and November 29, 2019, a self-administered questionnaire was distributed to a study sample consisting of students currently attending dental technology courses in Gangwondo and Gyeonggido. A total of 474 (94.8%) responses to the questionnaire were received and used for the final analysis. Results: Factors including major selection motivation, intrinsic motivation (p<0.001), academic adjustment (p<0.001), social adjustment (p<0.01), and institutional adjustment (p<0.05) all had negative relationships with academic dropout intention. Personal-emotional adjustment (p<0.001), however, showed a positive relationship with dropout intention. The explanatory power of the model was found to be 50.0%. Conclusion: This research shows that intrinsic motivation and personal-emotional adjustment diminish academic dropout intention. Therefore, it is recommended that diverse postenrolment course-adjustment programs should be developed to improve students' confidence in their choice of study, their adjustment to the course, and their level of satisfaction.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.201-208
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• 2022

As around the world, ground and underground transportation capacity is reaching its limit, centering on urban areas. As urban traffic becomes congested, time and cost are astronomical, and environmental destruction caused by urban pollution is becoming increasingly serious. As a way to solve this problem, the means of flying over the air are in the spotlight as the next generation of future transportation, and the concept of urban air mobility (UAM, Urban Air Mobility) is defined as systematic planning. The development of an electric-powered vertical take-off (eVTOL) aircraft that obtains electric power through a battery using a personal aerial vehicle (PAV) as a means of transportation has accelerated. As the aircraft development of new technology aircraft in the evtol method is actively carried out, the need to prepare systems such as aircraft certification standards, pilot qualification systems, and qualification management is emerging. The Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA), which lead international standards, announced new special technical conditions and temporary regulations SCVTOL-01, respectively. However, the pilot qualification system for operating the uam aircraft has not yet been clearly announced. Therefore, this paper analyzes the recently announced FAA regulations and EASA regulations to identify differences and directions in perspectives on UAMs and study the existing vertical take-off and landing aircraft (VTOL) pilot qualification system to present directions for qualification classification.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.9-14
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• 2008

In this paper, we propose the channel sounding scheme which is made for ideal communication between some application as well as the short distance of high speed data transmission in MIMO-OFDM system for Wireless PAN. This method is able to perceive the duration of the impulse response through the delaying of power delay profile, modeled a power delay profile which has an attenuate characteristic, and obtained the coefficient of channel response by ML (maximum likelihood). Through the amplitudes, phases and delays associated with each multipath component which were acquired from this channel sounding scheme, we can describe the wave propagation characteristics of channels between the transmitter and receiver so that the receiver could enhance not only the reliability but also the ability of communication link.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.32-38
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• 2006

When induction motor moves, power quality decline of line is risen seriously because provoking voltage drop the moment to system power supply by excessive moving current as well as power-factor drop in case drive by light-load because current reaches in 6 times $\sim$ 8 times of rated current. In this paper, a modeling did an distribution system 13 bus type model and induction machine load presents in IEEE using a PSCAD/EMTDE package, and it displayed an accident conspiracy and a compensating factor of DSTATCOM through simulation show.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.15-21
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• 2014

The aim of this work is conduct the study on light weight and structural performance improvement of the composite wind power blade. GFRP (Glass Fiber Reinforced Plastic) pre-empted by CFRP(Carbon Fiber Reinforced Plastic), the major material of wind power blade, was identified the superiority of mechanical performance through the tensile and fatigue test. SENT(Single Edge Notched Tension) specimen fracture test was conducted on the specimen that laminated together 2 ply CFRP with 4 ply GFRP through DIC(Digital Image Correlation) analysis. The SENT specimen thickness and $a_0/W$ ratio is 1.45 mm and 0.2, respectively. The fracture test accomplished with displacement control with 0.1 mm/min at the room temperature. The experimental apparatus used for the fracture test consisted of a 50kN universal dynamic tester and CCD camera connected to a personal computer (PC), which was used to record images of the specimen surface. Following data acquisition, the images and load-displacements were transferred to the PC, on which the DIC software was implement. The experiment and DIC analysis results show that CFRP/GFRP laminated composite exhibits improvement of the strength, compared with that of the existing blade material. This study shows the result that the strength of CFRP rotor blade of wind turbine satisfies through the experimental and DIC method.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.216-216
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• 1997

We developed the durability estimation and design systems to minimize the volume, considering the durability, efficiency, and design requirements of worm gears. That is, we consider each kind of factors affecting on durability on the basis of AGMA Standard for the cylindrical and double-enveloping worm gears. We also estimate input power on the basis of wear and durability, bending strength and deflection of worm shaft, and we developed the durability estimation and design systems of power transmission worm gears introducing the optimal design method on the personal computer to be easily used in field. Also, we developed a method which converts the design variables obtained from the optimal design method to integer values(number of worm threads, number of worm threads, number of worm wheel teeth, etc.,) to be used in real design and production. The developed durability estimation and design method can be easily applied to the design of worm gears used as power transmission devices in machineries and is expected to be used for weight minimization of worm gear unit.

• Korean Journal of Oriental Medicine
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• v.13 no.1 s.19
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• pp.85-92
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• 2007

To evaluate the suitability and effectiveness of the questionnaire concerning personal properties on 'pattern of speech and activity' according to the Sasang constitution that were used in Iksan Wonkwang Oriental Medicine, we analyzed the data of 1,335 patients obtained through the electronic chart in the aspect of 'relative discrimination ability' to Sasang constitutions and 'response ratio' using statistical Package SPSS. In categories of 'speech pattern', No.2 (speak mildly and softly) was effectively discriminating Soeum type. No.4 (talkative) and No.7 (speak fast) were effective factors for the discrimination of Soyang type, though No.4 (talkative) was needed to be improved in response ratio. The category of 'activity pattern' has shown high response ratio but low discriminating power. However, No.2 (keep staying home but avoid going out) in this category was effectively discriminating Soeum type. The discriminating power of 'pattern of speech and activity' for the age group less than 20 years old was too low, so it is necessary to develop the questionnaire for the elementary to high school students as well as for the preschoolers.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.282-290
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• 2003

AMR(Automatic Meter Reading) and RC(Remote Control) System have been researched from former several decade for a various power rate system, a efficient power service and rising of personal expenses, etc. But the existing AMR and RC System have disadvantage which are complex and high cost to install an individual communication network of electricity company. This paper proposed a new type of AMR and RC System using PLC with Web. and made components for proposal system. Most customer who live in apartment have an internet cable in the Republic of Korea. Therefore there is no more installation component for communication in proposal system at the apartment, except Web server system and PLC modem. so we made the PLC modem the digital watt-hour meter with a build in PLC modem and the software on server computer for establishing the proposal system.