• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.51-52
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• 2023

한국해양수산개발원(KMI) 조사에 따르면, 수상레저장비 중 하나인 전기 추진 보드류 (전동서핑보드, 전동웨이크보드, 전동패들보드 등)의 경제규모는 '28년도 까지 약 59억 달러까지 성장할 것으로 예측 될 정도로 급격한 성장을 하고있는 품목으로, 국내에서도 활발하게 제조, 수입, 유통 등이 이루어지고 있다. 하지만 성능 및 안전을 평가하는 정형화된 국내외 시험 표준이 전무한 실정으로, 시험 및 검사 없이 제조사의 자체 테스트에 의존하여 시장에 출시 되고 있다. 이에 신뢰성 있는 전기 추진 보드류 안전기준(안)을 개발 및 제시함으로써 제품의 품질 및 안전성을 향상시키고, 위해사고의 예방 및 국민의 건전한 수상레저활동 확보를 위한 기반을 조성하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.649-657
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• 1992

Transmission error for a stepping motor-timing belt drive system is investigated experimentally and analytically. From FFT analysis of the experimental results, it is found that the transmission error consists of three periodic errors : (1) error by the stepping motor per one resolution angle theta.$_{m}$, (2) error by the pulley eccentricity per one revolution theta.$_{e}$, and (3) error by the meshing effect between the belt and the pulley teeth per one pitch revoltion theta.$_{p}$. In order to investigate the effects of some design parameters on the transmission error, the dynamic models of the stepping motor-timing belt drive system are derived by Bondgraph. According to the simulation results, as the belt total tension increases, theta.$_{m}$ and theta.$_{e}$ decrease due to the nonlinearity of the belt. In adition, the numerical and experimental results show that theta.$_{m}$ and theta.$_{e}$ of the loaded case are larger than those of the unloaded case. The analytical results are in good accordance with the experimental results.sults.s.sults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1388-1392
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• 2013

Electric scooter has been using short-lived, low-efficiency DC motor. And motor control system is equipped with imported uniformly, so there is no product differentiation. Also, product design according to the characteristics of disability is difficult. In this study, BLDC motor control system to specialize in a electric scooter for disabled was developed with a semi-permanent features of life, low price, and high performance. This development will also contribute to the activation of the related industries, as well as be able to secure price competitiveness of domestic electric scooter.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.49-49
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• 2022

경기도 화성시 일대에서 미기록 침입외래식물인 서양전동싸리(Melilotus dentatus)를 발견하여 보고하고자 한다. 본 종은 아시아, 유럽 원산이며, 주로 경작지와 공원, 정원 등의 인공적인 환경에서 발견된다. 국내에서 발견된 서양전동싸리는 경작지 내 작물의 종자와 함께 국내로 유입된 것으로 추정되며, 농수로를 따라 인근 주변에서 약 15개체의 생육이 확인되었다. 국내 전동싸리속은 모두 외래식물로 현재 4종(M. suaveolens, M. albus, M. indicus, M. officianalis)이 보고되었으며 탁엽 기부가 엽병에 합착되고, 3출 우상복엽이며, 긴 총상화서, 난형 또는 난상타원형 열매를 가지는 공통된 형태적 특징으로 서양전동싸리와 혼동되기 쉽다. 그러나 본 종은 탁엽이 피침형이고, 소엽이 장타원형이며, 거치가 뚜렷하고, 배주가 2개이며, 종자의 색이 녹갈색인 특징으로 국내 근연 종들과 구분된다. 본 연구에서는 서양전동싸리의 실체와 생육환경을 확인하고, 그 결과를 바탕으로 형태학적 기재 및 화상자료를 비롯하여 주변식생 목록과종 식별을 위한 검색표를 제시하고자 한다.

• Archives of design research
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• v.17 no.1
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• pp.383-392
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• 2004

The power tools is the product using working power generated by electric motor. Many companies are manufacturing numerous devices. Main features of tools are included various assembled products, small, light and solid and durable enough to match several standards. Fundamental requirements for the product is excellent performance and convenience for use. The quality of them depends on the equipped motor'(s) capability, accuracy of gear and endurance against worn-out. By adapting the state-of-the-art parts, they could be used in the place from home to heavy industry broadly. They can be classified electronic drills, grinders, saws and sanders families for the household appliances. For industrial tools, bore drill, grinder, polisher, and driver drill are classified as special and high priced group. This study presents the strategy of power tool development of BOSCH, BLACK&DECKER and KEYANG. Their products were analyzed in terms of product line and product mix concept. Then they are examined by design elements, such as color, shape and material for housing. As an analysis method, the image scale parameter and criteria were applied to each company's product.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.133-139
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• 2016

An electric wheelchair is a assistive device to maneuver on the ground. Tip-over of an electric wheelchair is increasing every year. Dynamic stability metric test item in KS P 7176 has not ensured safety of electric wheelchair on the slope. This study presents design the foldable electric wheelchair that can load in the car and analysis of tip-over measurement which is easily computed for electric wheelchair. Wheelchair frame is designed with a four-bar link mechanism for a foldable structure, and seat module, battery and power driving module can be separated. This analysis is performed during a maneuver on the ground by force-moment stability metric. Several elements, center of gravity position, rotational radius and acceleration, were evaluated how to affect stability metric. This stability metric can reduce tip-over of wheelchair and provide a clue to make of dynamic stability test item.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.93-99
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• 2019

Small electric vehicles, such as electric bicycles or electric kickboards, operate with the power charged in a battery mounted in the vehicle, and some of these users use emergency power sockets installed in apartments or public facilities without getting permission. For this reason, the necessity for a simple method to approve the use of power with instant payment system rises for the building managers and small vehicle users as well. In this paper, we propose a technique to charge batteries for small electric vehicles with less than 1 [kW] through a power supply control device installed on the existing 15 [A]. sockets on the common residential properties or public buildings. It also describes the power user authorization algorithm and how to charge fees for the power used. As a result of this research, this paper shows how the user authentication power supply system with the effect of preventing power theft can be realized by creating an environment in which a battery in a small electric vehicle can be easily charged.

• Journal of Digital Contents Society
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• v.16 no.3
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• pp.355-363
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• 2015

In this paper, we propose a system for controlling the seat of the electric wheelchair depending on the slope of the terrain in real time by using the ATmega smart control based on the board. Smart control board includes a gyro sensor, an acceleration sensor and Tilt sensor, when the electric wheelchairs pass slope of the terrain, they use three sensors to identify terrain configuration in real time. We also applied the Complementary Filter in the gyro sensor and acceleration sensor, so the electric wheelchairs know the exact terrain by solving the interference during the movement. Based on this, the noise power wheelchair due to the movement will be reduced, the seat continues reliably movement without being vibration. In this paper, providing an application on the smart phone platform for the convenience of users who are not familiar with how to use electric wheelchairs, they can easily control wheelchairs. Control platform of the smart phone is able to monitor the electric wheelchair in real-time, with regard to pressure prevention, help the slope of the seat to be arbitrarily controlled.

• Journal of the Korean Society for Railway
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• v.14 no.2
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• pp.167-173
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• 2011

This paper considers the problem of revising train departure time to reduce electric power consumption of mass rapid transit (MRT) railways. The motion of a train running between stations is divided into three phases: traction, coasting, and deceleration phases. The traction phase requires high electric power to operate MRT railways. In the coasting phase, the train moves stably by consuming little or no power. The deceleration phase is a braking mode and produces some electric power called regenerated brake power owing to inertia force for the train generated In the traction and coasting phases. The regenerative energy can be used by other accelerating trains within a specific range from the train and thereby the power consumptions of train can be reduced. We developed a mixed integer programming model to solve the problem. To validate the suggested model, a computational experiment was conducted using real data from Korea Metropolitan Subway.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.175-182
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• 2013

Rolling noise is an important source of noise from railways; it is caused by wheel and rail vibrations induced by acoustic roughness at the wheel/rail contact. To reduce rolling noise, it is necessary to have a reliable prediction model that can be used to investigate the effects of various parameters related to the rolling noise. This paper deals with modeling rolling noise from wheel and rail vibrations. In this study, the track is modeled as a discretely supported beam by regarding concrete slab tracks, and the wheel vibration is simulated by using the finite element method. The vertical and lateral wheel/rail contact forces are modeled using the linearized Hertzian contact theory, and then the vibration responses of the wheel and rail are calculated to predict the radiated noise. To validate the proposed model, a field measurement was carried out for a test vehicle. It was found that the predicted result agrees well with the measured one, showing similar behavior in the frequency range between 200 and 4000 Hz where the rolling noise is prominent.