• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.720-725
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• 2008

This paper proposes a system architecture for USN with a service robot to provide more active assisted living services for elderly persons by monitoring their mental and physical well-being with USN environments at home, hospital, or silver town. Sensors embedded in USN are used to detect preventive measures for chronic disease. Logged data are transferred to main controller of a service robot via wireless channel in which the analysis of data is performed. For the purpose of handling emergency situations, it needs real-time processing on gathering variety sensor data, routing algorithms for sensor nodes to a moving sink node and processing of logged data. This paper realized multi-hop sensor network to detect user movements with biometric data transmission and performed algorithms on Xenomai, a real-time embedded Linux. To leverage active sensing, a mobile robot is used of which task was implemented with a priority to process urgent data came from the sink-node. This software architecture is anticipated to integrate sensing, communication and computing with real-time manner. In order to verify the usefulness of a proposed system, the performance of data transferring and processing on a real-time OS with non real-time OS is also evaluated.

• Journal of Electrical Engineering and Technology
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• v.3 no.4
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• pp.528-537
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• 2008

Primary frequency control(PFC) has the ability to regulate short period random variations of frequency during normal operation conditions and also to respond rapidly to emergencies. However, during the past decade, numerous significant sized blackouts occurred worldwide that resulted in serious economic losses. Therefore, the conclusion has been reached that the ability of the current PFC to meet an emergency is poor, and security of power systems should be improved. An alternative to enhance the PFC and thus security is to store excessive amounts of energy during off-peak load periods in efficient energy storage systems for substituting the primary control reserve. In this sense, superconducting magnetic energy storage(SMES) in combination with a static synchronous compensator(STATCOM) is capable of supplying power systems with both active and reactive powers simultaneously and very rapidly, and thus is able to enhance the security dramatically. In this paper, a new concept of PFC based on incorporating a STATCOM-SMES is presented. A complete detailed model is proposed and a new control scheme is designed, comprising an enhanced frequency control scheme, and a fully decoupled current control strategy in d-q coordinates with a novel controller to prevent dc bus capacitors voltage drift/imbalance. The performance of the proposed control schemes is validated through digital simulation carried out using MATLAB/Simulink.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.275-288
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• 2010

In order to improve the quality of electricity in large scale power systems, stability of power system has to be achieved. This can be done by the means of preventative diagnosis of power equipments and protection, monitoring and control of the power system. Since the recent adoption of digital controllers, an improvement in stability was observed; in particular, IED, which contained self-diagnostic abilities such as fault tolerance, allowed for automatic recovery via redundancy or switching-over functions should there be faults with the equipments. Furthermore, communication lines have been hugely simplified, thus adding to the improvement in stability significantly. Taking these error reports and forecasting emergency reports and by effectively responding to them in the overiding controlling systems, high levels of system stability can be obtained. Power Management System that is being applied to automated power sub-stations, takes the IEC61850 international standard as its specification. In this paper, additional research into achieving stability of already developed PMS system and also the stability of the overall system was carried out, and the results of development of communication servers, which play a pivotal role in connecting systems, are stated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.189-193
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• 2009

As large-scale buildings, skyscrapers, and multi-purpose buildings recently increase in numbers dramatically the internal space of such buildings becomes more and more large and complicated accordingly. The Multi-purpose buildings are increasing rapidly in number, and concerns over the evacuation process in case of fire emergency are also increasing. However, A controller who is responsible for visitor's safety makes a decision about measures for visitor safety in human based decision making process. Many potential accidents that are caused by human error lurk in results of the process. The accidents can be decreased by changing the decision making process from human-based into technology-based. Through this study, the way to improve current disasters prevention system is presented and it can also improve shelter inducement methods effectively. SICS(Spatial Information Control System) which is being studied in other research is used as the tool for improvement.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.108-113
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• 2021

Recently, a new concept of a one-touch descending lifeline has been proposed to address the drawbacks of the conventional descending lifeline, which can be easily installed and quickly evacuated in the case of a fire emergency. All separate parts for escape are initially mounted in a box, and the link-type support is spread out of the window by pushing the handle attached to the box. In this study, the proposed double square linkage mechanism was redesigned, and its safety is verified by determining an appropriate moment of inertia of the link through finite element analysis using Abaqus. The shape and assembling method of the reel and speed controller were also modified such that the safety belt was simultaneously unfolded with link-type support. Finally, the feasibility of the proposed one-touch all-in-one descending lifeline was confirmed through fabrication.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.2
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• pp.78-85
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• 2022

항공교통관제사와 조종사 사이의 의사소통은 항공기 운항 안전에 있어서 매우 중요한 요소이다. 국제민간항공기구(ICAO)는 민간항공운송산업의 발전과 안전 도모를 위해 조종사 영어자격능력 시험을 의무사항으로 규정하고 있다. 왜냐하면 조종사의 우수한 의사소통능력은 비상상황 또는 비정상상황을 즉각적으로 대응할 수 있는 매우 필수적인 능력들 중 하나이기 때문이다. 대한민국 국토교통부는 2006년부터 ICAO EPTA 시험을 민간항공운송에서 조종사 의무자격시험으로 법적으로 규정하고 산하기관인 교통안전공단을 통해 시험을 주관하고 있다. 본 연구는 EPTA 시험에 응시하는 응시자의 시험에 대한 신뢰성을 증진시키고 시험제도의 발전방안을 모색하고자 하였다. 이를 위해 본 연구는 첫째, EPTA 시험제도와 관련한 이론적 배경을 고찰하였다. 둘째, EPTA 시험제도의 국내에서 정착 및 발전과정을 살펴보았다. 셋째, EPTA 시험제도의 신뢰성증진 및 발전방안 모색을 위해 총 15명의 항공전문가들을 대상으로 질적 연구를 수행하였다. 본론의 질적연구를 통해 연구자들은 국외 ICAO 공식 인증 EPTA 시험결과와 국내 교통안전공단이 주관하는 EPTA 시험결과를 바탕으로 교차응시에 따른 EPTA 등급을 비교·분석할 수 있었으며 시험응시자들에 대한 인터뷰를 통해 국내 EPTA 시험 발전을 위한 개선방안을 도출하였다.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.51-58
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• 2021

This study proposes the design and implementation of a low-cost emergency ventilator which can be helpful during the COVID-19 pandemic where the supply of automatic ventilators is not smooth compared with the urgent demand worldwide. Easy implementation and lower price were made possible by using AMBU-bag and off-the-shelf embedded micro-controller board. Moreover, while 3D printing is used by companies and experts around the world to build prototype hardware, materials which are readily available from surrounding environments so that people in countries where it is difficult to access many advanced technologies could manufacture the system. The design features AMBU-bag automation, not use 3D printing, and it can contrl speed. By allowing speed control, ventilation can be performed according to the conditions of the patient being used. A complementary point in the study is that it is difficult to fix the start point of the wiper motor used first. A method for complementing this is a method for replacing the brush DC motor with a position feedback function. Secondly, the AMBU-bag may wear out in the long-term process of compressing the AMBU-bag because the arm and the fixing frame are made of wood. To complement this, the part of fixing frame and arm parts that the AMBU-bag touches need to be wrapped in a material such as silicon to minimize friction.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.528-533
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• 2013

To improve the efficiency and safety of railway systems, the train control system has considerably evolved from the ground-equipment-based control system (e.g. track circuit, interlocking system, etc.) into the on-board-equipment-based control system. In addition, this train control system enables the rolling stock to intelligently control the trackside facilities by introducing information and communication technologies (ICT). Accordingly, since the ICT-based train control system simplifies the railway system (i.e. the heavy ground-equipment can be removed), an efficient and cost-effective railway system can be realized. In this paper, we perform a feasibility test of the ICT-based train control system using a simulation. To this end, we implement a test-bed consisting of prototype machines of on-board/ground equipment and introduce an integrated operation scenario for the train control. The simulation results satisfy all the requirements of train operation according to the scenario and show the effectiveness of the proposed train control system.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.42-48
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• 2020

This research illustrates how the hybrid engine system comprising of a two-cycle reciprocal engine with an integrated generator and a battery is prepared for the design process. The purpose of this research is to increase flight endurance taking advantage of the high energy density of hybrid propulsion systems as well as to cope with current environmental issues by reducing fossil fuel. The hybrid system is designed to offer 6 kW power, and the power can be adjusted by controlling the engine's RPM in accordance with load variations. In addition, the battery is adopted to offer extra electric power that this hybrid system cannot cover, and can function as the main power source in limited time in the case of an emergency situation. Besides that, the generator is directly mounted on an engine crank-shaft, and in turn, they can share the same RPM. Thus, it is hypothesized that this integration method can make a compact design possible by reducing space for the installation in the fuselage of UAVs.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.156-161
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• 1992

In this research a monitoring system for turning using NC information and the current of feed motor as a monitoring signal was developed. The overall system consists of modules such as learning process, NC data transmission, generation of forecast information, signal acquisition, monitoring and post process. In the learning process, the reference data and the cutting force equation necessary for monitoring are obtained from the accumulated monitoring results. In the generation of forecast information, the information of forecasted cutting forces is acquired from the cutting force equation and NC program and appended to each NC block as a monitor code. Reliability of monitoring is improved by using the monitor code in the real-time monitoring. Monitoring module is divided into two parts : the off-line monitoring where errors of NC program are checked and the on-line monitoring where the level of motor current is monitored during cutting operations. If the actual current level exceeds the limit value provided by the monitor code in the level monitoring, it is recognized as abnormal. In the event of abnormal status, the post processor sends the emergency stop signal to NC controller to stop the operation. Actual experiments have shown that the developed monitoring system works well.