• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.32-35
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• 2020

본 논문은 실시간 데이터 분석을 위한 컨테이너 가상화 기술 사용에 대한 효용성을 알아보기 위해 HDP 와 MapR 배포판에 포함된 Spark 를 도커라이징 전과 후 환경에 설치 후 HiBench 벤치마크 프로그램을 이용해 성능을 측정하였다. 그리고 성능 측정치에 대해 대응표본 t 검정을 이용하여 도커라이징 전과 후의 성능 차이가 있는지를 통계적으로 분석하였다. 분석 결과, HDP 는 도커라이징 전과 후에 대한 성능 차이가 있었지만 MapR 은 성능 차이가 없었다.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.308-317
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• 2012

Reactive processing, such as reactive hot pressing (RHP) and reactive spark plasma sintering (R-SPS), is effective densification method to prepare $ZrB_2$-based ultra high temperature ceramics (UHTCs). The present paper reviewed some typical reactive processing of $ZrB_2$-based UHTCs. All the reactions from the starting materials in the reactive processing are thermodynamically favorable, which generate enough energy and driving force for the densification of the final products under a relatively low temperature. Besides, compared with non-reactive processing, anisotropic $ZrB_2$ grains, such as $ZrB_2$ platelets, can only be obtained in the reactive processing, resulting in an improvement of the mechanical properties.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.3
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• pp.255-260
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• 2002

Recently, the occurrences of electrical fire have been suppressed by an earth leakage breaker(ELB), a no fuse breaker(NFB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the ELB to break the circuit in the case of the failure of pressure contacts on connecting points and the momentary short circuit. Therefore, it is require to study the constructive problem of the ELB. In this paper, we have developed the auxiliary control device, electrical fire prevention control device(EFPCD), of the ELB. And we have tested the operation characteristics of the ELB according to the load(R, L) As a result of this experiment, we could prevent the electrical fire due to the spark and the overheat occurring in the failure of pressure contacts on connecting points and the momentary short circuit.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.133-139
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• 2018

Precipitator is the most widespread device used to separate dust particles from the exhaust gas. In the shipyard, welding umbrellas, spark protection covers, and ventilators are not purchased and used for the work place to capture the flames and high temperature metal dust generated during the gardening process. In particular, a thorough analysis of design factors, such as capture rate, collection capacity calculation, filter speed, and materials selection, is required since spatial constraints are followed by structures, etc. In this study, conceived to address problems such as this cyclone and filtration filter system that combines all-in-one gausing collector prototype. Assessed through interpretation through the validity of the design and reliability.

• International Journal of Automotive Technology
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• v.5 no.3
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• pp.195-200
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• 2004

This paper is concerned with the Homogeneous Charge Compression Ignition (HCCI) engine as a new concept in engines and a power source for future automotive applications. Essentially a combination of spark ignition and compression ignition engines, the HCCI engine exhibits low NOx and Particulate Matter (PM) emissions as well as high efficiency under part load. The objective of this research is to determine the effects of Exhaust Gas Recirculation (EGR) rate on the combustion processes of HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine, and a heating device was installed to raise the temperature of the intake air and also to make it more consistent. In addition, a pressure sensor was inserted into each of the cylinders to investigate the differences in characteristics among the cylinders.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1854-1856
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• 1996

This study describes the minimum ignition limit for LPG-Ai-r mixtures by switching sparks in radio-frequency limits using RF power supply and IEC type ignition spark apparatus. As a result, the minimum ignition limit voltage is increased in proportional to the rate of increasing of frequency in LPG-Air mixed gas. Especially, increment between 10[kHz] and 30[kHz] is typical. It is considered that ignition is caused by one discharge until 10 [kHz] and, beyond 10[kHz] ignition is caused by more than two discharges. The reason is analysed that energy loss is caused by existing pause interval between discharges.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.65-75
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• 2001

Modern vehicles require a high degree of refinement including good driveability. Vehicle driveability, which becomes a key decisive factor f3r marketability, is affected by many parameters such as engine control and the dynamic characteristics in drive lines. Therefore engine and drive train characteristics should be considered to achieve a well balanced vehicle response simultaneously. This paper describes experimental procedures which have been developed to measure engine torque and investigate shuffle characteristics. To analyze the vehicle dynamic behavior, fractional torques and inertia mass moment of engine, and drive train were measured. Shuffle characteristics during tip-in condition were investigated in an experimental vehicle at 2nd and 3rd gear stages. It was found that the shuffle characteristics were caused by sudden changes of engine torque and have a different vibration frequency with gear stage variation. Inertia mass moment of engine including flywheel rotation showed a key factor for the shuffle characteristics.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.85-91
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• 2001

LPG has been well known as a clean alternative fuel for vehicles. As a fundamental study on liquid phase LPG injection (hereafter LPLI) system application to heavy-duty engine, engine output and combustion performance were investigated with various operating conditions using a single cylinder engine equipped with the LPLI system. Experimental results revealed that no problems were occurred in application of the LPG fuel to heavy-duty engine, and that volumetric efficiency and engine output, by 10% approximately, were increased with the LPLI system. It was resulted from the decrease of the intake manifold temperature through liquid phase LPG fuel injection. These results provided an advantage in the decrease of the exhaust gas temperature, in the control of knocking phenomena, spark timing and compression ratio. The LPLI engine could normally operated under $\lambda$=1.5 or EGR 30% condition. The optimized swirl ratio for the heavy duty LPG engine was found around R_s$ = 2.0.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.5
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• pp.428-435
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• 2019

A comparative evaluation of engine cleanliness was performed on the transport gasoline blended with bio- alcohols, and this study was considered to achieve the aim of greenhouse gas reduction in Korea. In particular, the fuel blended with bio-ethanol and bio-butanol showed the best engine cleaning performance both on combustion chamber deposits and intake valve deposits. The deposit control gasoline additive was effective to remove intake valve deposits. In contrast, the amount of combustion chamber deposits were tend to increase even though fuels blended with bio-alcohols were used. In overall, fuels blended with bio-alcohols, compared to fossil fuels, still showed outstanding performance in terms of engine cleanliness.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.63.1-63.1
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• 2019

1953년에 밀러와 유리는 초기 지구 대기와 해양을 모사하여 단순한 기체 조합으로부터 유기분자를 얻었다. 생명의 기원을 논할 때 언급되는 밀러유리 실험을 교육 현장에서 활용하고 현대적으로 해석하고자 2014년에 Parker 등에 의해 재조명되어 단순화된 장치로 실험실을 설계하여 전기방전 실험을 진행하였다. 실험장치에 사용한 유리기구는 산, 염기로 각각 세척하고 200도씨 오븐에 건조하였다. 300ml 의 물을 반응 플라스크에 넣고, 83mmHg(11kPa) 압력의 진공상태에서 암모니아 100mmHg, 메탄 200mmHg, 질소 100mmHg를 주입하였다. 총 16일의 실험 기간중 66시간 방전을 하였다. 전기 방전 색이 하늘색에서 보라색으로 바뀌는 것을 확인하고 분광스펙트럼을 얻었으며, 시간에 따른 대기조성의 변화를 해석하고자 한다. 이 실험은 교내 창의연구활동 (R&E와 졸업개인연구)의 하나로 2015년부터 학생 주도적으로 진행되고 있다.