• Fire Science and Engineering
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• v.20 no.1 s.61
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• pp.71-76
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• 2006

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device(RCD) of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms](KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this paper is proposed to a auxiliary control apparatus for RCD trip on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.89-93
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• 1989

In this paper, a mathematical engine model based on the actual engine operation is formulated to be adapted for the evalution and development of engine control system. In the model the classification of fuel paticle siza is considered. The model is simulated through the mathematical interpretation of intake manifold in the rapidly-accerated state. The spark-timing is analyzed with respect to engine r.p.m. The result shows that the model behaves similar performance to the actual engine operation and the spark-timing is very important to the characterization of engine r.p.m..

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.210-213
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• 2005

This article describes an estimate method of the spark plug gap by measuring breakdown voltage. Breakdown voltage is the function of spark plug gap, pressure, temperature and humidify. However. It is dominated mainly by the spark plug gap. This technique is applied to in-line process test of the spark plug gap in automobile engine production. Breakdown voltage of normal spark plugs slightly scatters in ordinary conditions and if there is dust or burr in the gap, breakdown voltage gets lower. This technique saves repairing time for bad spark plug and attributes to improve the quality of automobile engine.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.15-16
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• 2017

IoT 시대가 도래함에 따라 실시간으로 대규모 데이터가 발생하고 있으며 이를 효율적으로 처리하고 활용하기 위한 분산 처리 및 기계 학습에 대한 관심이 높아지고 있다. 아파치 스파크는 RDD 기반의 인 메모리 처리 방식을 지원하는 분산 처리 플랫폼으로 다양한 기계 학습 라이브러리와의 연동을 지원하여 최근 차세대 빅 데이터 분석 엔진으로 주목받고 있다. 본 논문에서는 아파치 스파크 기반 기계 학습 라이브러리 성능 비교를 통해 아파치 스파크와 연동 가능한 기계 학습라이브러리인 MLlib와 아파치 머하웃, SparkR의 데이터 처리 성능을 비교한다. 이를 위해, 대표적인 기계 학습 알고리즘인 나이브 베이즈 알고리즘을 사용했으며 학습 시간 및 예측 시간을 비교하여 아파치 스파크 기반에서 실시간 데이터 처리에 적합한 기계 학습 라이브러리를 확인한다.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.11-17
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• 2010

This study investigates the non-traditional manufacturing process of dry wire electrical discharge machining (EDM) in which liquid dielectric is replaced by a gaseous medium. Wire EDM experiments of thin workpieces were conducted both in wet and dry EDM conditions to examine the effects of spark cycle (T), spark on-time ($T_{on}$), thickness of work pieces, and work material on machining performance. The material removal rate (MRR) in the dry wire EDM case was much lower than that in the wet wire EDM case. In addition, the thickness of workpiece and work-material were found to be critical factors influencing the MRR for dry EDM process. The relative ratios of spark, arc and short circuit were also calculated and compared to examine the effectiveness of processes of dry and wet wire EDM.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.79-80
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• 2016

아파치 스파크는 효율적으로 대용량 데이터를 처리하기 위해 분산 메모리 추상화를 사용하는 오픈 소스 분산 데이터 처리 플랫폼이다. 하지만 아파치 스파크 플랫폼의 특정 작업의 성능은 입력 데이터의 유형과 크기, 디자인 및 알고리즘의 구현 및 컴퓨팅 능력에 따라 메모리 사용량 및 I/O 비용이 크게 달라질 수 있다는 문제점이 있다. 이러한 문제점을 해결하기 위하여 본 논문에서는 아파치 스파크 플랫폼에 대한 높은 정밀도 작업 성능을 예측할 수 있도록 CPU core수의 증가에 따른 WordCount 시뮬레이션을 비교 평가 하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.67-68
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• 2016

최근 빅 데이터를 이용한 시스템들이 여러 분야에서 활발히 이용되기 시작하면서 대표적인 빅데이터 저장 및 처리 플랫폼인 하둡(Hadoop)의 기술적 단점을 보완할 수 있는 다양한 분산 시스템 플랫폼이 등장하고 있다. 그 중 아파치 스파크(Apache Spark)는 하둡 플랫폼의 속도저하 단점을 보완하기 위해 인 메모리 처리를 지원하여 대용량 데이터를 효율적으로 처리하는 오픈 소스 분산 데이터 처리 플랫폼이다. 하지만, 아파치 스파크의 작업은 메모리에 의존적이므로 제한된 메모리 환경에서 전체 작업 성능은 급격히 낮아진다. 본 논문에서는 메모리 용량에 따른 아파치 스파크 성능 비교를 통해 아파치 스파크 동작을 위해 필요한 적정 메모리 용량을 확인한다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.5-6
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• 2014

According to 2013 fire statistical yearbook in the National Emergency Management Agency, the main cause of an electrical fire are classified to short circuit fault, overload fault, electric leakage, partial disconnection, and joint/contact badness. The occurrence factor of fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Devices(RCDs) of high sensitivity type used at single phase (220V) cut off earth leakage and overload but the RCDs can not cut off electric arc or spark to be a main cause of electrical fire. To be improved on such problem, this thesis is proposed to a auxiliary control device for RCD cut off electric arc or spark.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.94-101
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• 2007

This paper, we analyzed that the measured data of the radiated power spectrum of electromagnetic waves and the standing wave ratio(SWR) of the spark plug cable and spark plug. The measured data are the power strength of the electromagnetic waves radiated from the spark ignition system, the measured frequency ranges are 110 to 610MHz. The results show that the strength of radiated power spectrum and bandwidth have relation to the SWR of the the spark plug cable and spark plug, and the SWR of them is different because of the characteristics of resistor at the spark plug is different with the manufacturers. From the analyzed results, it can be concluded that the less SWR is little, the less maximum level of power spectrum is weak and bandwidth above the reference level is small.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.288-298
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• 1999

In spark ignited engines, the electrical spark not only sets the time for the onset of combustion but also is able to greatly influence the character of the initial flame growth and the subsequent combustion, and thereby can influence engine performance. The relative importance of the ignition energy is particularly high under lean or high residual gas or exhaust gas recirculation (EGR). In this study, a modeling of flame Initiation and its development is proposed. Submodels consist in representing of cylinder pressure and temperature, heat transfer to cylinder wall, and flame kernel heat transfer to ambient air and to spark plug electrodes. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy, and laminar and turbulent flame velocity.