• Proceedings of the KSR Conference
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• 2005.11a
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• pp.694-698
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• 2005

The operation speed improvement of the train in electric railway must pursue continuously and need the investigation of whole railway system whole. The high-speed of the train is related to not only vehicle technique but also the infrastructure, signal system, operation technique, the trolley line and catenary, economical efficiency. Specially, in case of electric railway, we have to consider a technical investigation which is current collection efficiency improvement, voltage drop countermeasure, equipment capacity, track force, signal system. In this paper, we presents the technical investigation of AT feeder system in order to achieve high speed train in exist real railroad. We proved this approach which will use the whole domestic lines in the future.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.221-222
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• 2015

ITER AC/DC Converter의 부하는 초전도 코일이며 이에 필요한 컨버터는 총 6종류(2상한:TF, 4상한:PF, CS, VS, CCU/L, CCS)가 있다. 이중 VS 컨버터(${\pm}1050V$, ${\pm}22.5kA$)는 6대가 직렬로 접속되어 운전되고 CS 컨버터(${\pm}1050V$, ${\pm}4.5kA$)는 4대가 직렬로 접속되어 운전한다. 이들 컨버터용 제어기의 개발 단계에서 실 부하상태를 준비하는 것은 어렵기 때문에 $RTDS^{TM}$ (Real Time Digital Simulator)를 이용하여 제어 대상인 High Power 부분과 초전도 코일의 동적 시스템 모델을 HILS(Hardware-in-the-Loop Simulation)로 구축하였다. 본 논문에서는 HILS 구축에 대한 상세한 내용과 이를 활용하여 Control 시스템을 검증한 결과를 서술하였다.

• Journal of Drive and Control
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• v.20 no.3
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• pp.1-8
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• 2023

The purpose of this study was to investigate and compare the impact of engine load on the emission characteristics of excavator engines, with the aim of improving the method for calculating the emission inventory of construction machinery. The engine load in excavators is directly correlated with the operational workload, and variations in the load factor (LF) can significantly influence the emission inventory. Thus, on-board diagnostic (OBD) data from an excavator at a construction site were systematically collected to measure engine output and emissions. The results revealed discernible differences in emissions based on engine load, even when the average excavator engine performance remained constant. This highlights the significant influence of the type and characteristics of the work being carried out on emission characteristics. Making realistic adjustments to the LF used in emission calculation formulas emerges as a crucial strategy for environmental improvement. Moreover, the analysis of the effects of engine load on emissions from excavators provides valuable insights for enhancing environmental protection measures.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.203-204
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• 2017

ITER AC/DC Converter Local Controller는 ITER 토카막 초전도 코일 전류를 제어하는 것으로 코일 전류 충전, 유지, 방전 및 보호 동작이 요구되며 토카막 제어실에서 Real time 통신으로 명령되는 실시간 전압 명령을 추종해야 한다. 대용량 Utility 및 대전류 초전도 코일 실부하에서 제어기 개발 시험은 불가능하므로 RTDS를 이용하여 제어기의 성능을 검증할 수 있다. 본 논문은 RTDS를 이용하여 전원 장치 제어기의 시험 된 내용을 논의 하고자 한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.379_380
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• 2009

고온 초전도 전력케이블은 기존 케이블에 비해 많은 전력을 공급할 수 있기 때문에 대용량 신규부하 밀집지역이나 노후 전력케이블 교체시 대용량 송전을 가능하게 하는 대안으로 관심이 많아지고 있다. 그러나 고온 초전도 케이블은 전기적인 특성이나 냉각시스템을 필요로 하는 등 기존 케이블과 다른 많은 특성을 가지고 있기 때문에 실계통에 투입하기 이전에 초전도 케이블의 신뢰성 검증 및 평가가 새롭게 검토해야할 사안들로 받아들여주고 있다. 이를 위해서는 국내외적으로 진행된 많은 고온 초전도 전력케이블에 시험 데이터 및 경험을 근거로 실계통에 적합한 새로운 신뢰성 평가방법을 제시되어야 한다. 본 논문에서는 국내외적으로 진행된 고온 초전도케이블의 신뢰성평가 방법을 검토하고 국내에서 개발중인 세계최고의 전압인 154kV 고온 초전도 전력케이블에 대한 신뢰성 평가방법을 제시하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.517-524
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• 2004

In this paper the novel operation method of concentration winding BLDC motor of air conditioner compressor to improve efficiency is proposed.. Because it demands generally the need of more confidential sensorless operation, it Is hard to apply to three phases - three excited operation by reason of intricate calculations. In order to improve the defects of 120 degrees electrical conduction method, a novel PW Pattern is proposed. Established three phases - two excited system on real load air conditioner is used in experiment.

• The KIPS Transactions:PartB
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• v.8B no.3
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• pp.261-268
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• 2001

연속형 미디어는 대용량이고 실시간으로 전송되어야 하므로 전송에 요구되는 네트워크 자원에 부하를 준다. 일반적으로 프락시는 자주 참조되는 객체를 캐슁하여 서버로의 네트워크 전송 대역폭을 줄이기 위한 기법으로 사용되고 있으나 기존의 연구들이 이미지나 텍스트 등의 비 실 시간성 객체 지향적으로 설계되어 실 시간성 객체의 서비스에는 적합하지 않다. 그러므로 본 논문에서는 패칭기법[10]을 사용한 프락시 관리 기법을 사용하여 연속형 스트림 서비스를 하는 스트림 서비스 기법을 제안한다. 제안한 기법에서는 프락시에 캐슁된 데이터의 양에 따라 스트림 전송 방식을 달리한다. 첫째, 요청된 객체 전체가 캐슁되어 있을 경우 프락시 만으로 서비스한다. 둘째, 요청된 객체가 전혀 캐슁되어 있지 않을 경우 후행 스트림들이 서버로부터 객체를 전송할 때 발생하는 초기 지연을 상쇄할 만큼의 데이터를 선반입한다. 셋째, 일부분만이 캐슁된 경우에는 해당 객체를 요청하는 스트림 사이에 존재하는 양만큼의 데이터를 프락시에 패칭하며 이 경우에는 사용자 노드는 두 개의 채널을 열어 하나는 프락시에 패칭된 데이터를 읽는데 사용하며 또 하나의 채널로는 서버로부터 나머지 부분을 읽어오는데 사용한다.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.822-826
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• 2009

In case of engine room of ship, it uses type 2 ventilation system which supplies outside air forcibly by engine room ventilation fan, and naturally discharges air to outlet through low-pressed casing. The advantage of type 2 ventilation is that it makes inside with bi-pressure status to discharge contaminated materials to outside naturally. However, there is a phenomenon that pressure is greatly different between outside and inside due to huge amount of air supply by engine room ventilation fan. Therefore, we went aboard a container vessel which is on test run to analyze differential pressure with micronanometer by engine load and by combustion air supply method of engine. As a result, as engine load decreases (50, 75, 100%), the differential pressure between outside and inside tends to increase by 35% average, and the difference of pressure was 6.5 times maximum by combustion air supply method of engine.

• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.49-56
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• 2021

In this study, we investigated the necessary mechanical properties of conductive multifilament yarns for fabricating the electrodes of biosignal measurement pressure and stretch textile sensors using embroidery. When electrodes and circuits for smart wearable products are produced through the embroidery process using conductive multifilament yarns, unnecessary material loss is minimized, and complex electrode shapes or circuit designs can be produced without additional processes using a computer embroidering machine. However, because ordinary missionary threads cannot overcome the stress in the embroidery process and yarn cutting occurs, herein, we analyzed the S-S curve, thickness, and twist structure, which are three types of silver-coated multifilament yarns, and measured the stress in the thread of the embroidery simultaneously. Thus, the required mechanical properties of the yarns in the embroidery process were analyzed. In the actual sample production, cutting occurred in silver-coated multifilament rather than silver-coated polyamide/polyester, which showed the lowest S-S curve. In the embroidery process, the twist was unwound through repetitive vertical movement. Further, we fabricated a piezoresistive pressure/tension sensor to measure gauge factor, which is an index for measuring biological signals. We confirmed that the sensor can be applied to the fabrication of embroidery electrodes, which is an important process in the mass production of smart wearable products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.457-467
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• 2020

Increasing environmental concerns have prompted countries around the world to tighten regulations on greenhouse gases and fuel efficiency. Research is being done using advanced driver assistance systems to improve fuel economy and for the convenience of drivers. Research on systems such as adaptive cruise control (ACC), LKAS, and AEB is active. The purpose of ACC is to control the longitudinal speed and distance of the vehicle and minimize the driver's load, which is considered useful for accident prevention. From this point of view, research has used a mathematical method of safety evaluation as a function of distances and scenarios while considering domestic road environments. A vehicle is tested with a simulation in a proposed scenario. The purpose of the analysis is to verify the functional safety of ACC by comparing the theoretical calculations using theoretical equations, the relative distances in the simulation, and an actual vehicle test. These methods are expected to enable many companies to use scenarios, formulas, and simulations as safety verification methods in the development of ACC.