• Journal of the Korea Convergence Society
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• v.7 no.5
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• pp.1-6
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• 2016

Many studies have been carried out for the development of big data utilization and analysis technology recently. There is a tendency that government agencies and companies to introduce a Hadoop of a processing platform for analyzing big data is increasing gradually. Increased interest with respect to the processing and analysis of these big data collection technology of data has become a major issue in parallel to it. However, study of the collection technology as compared to the study of data analysis techniques, it is insignificant situation. Therefore, in this paper, to build on the Hadoop cluster is a big data analysis platform, through the Apache sqoop, stylized from relational databases, to collect the data. In addition, to provide a sensor through the Apache flume, a system to collect on the basis of the data file of the Web application, the non-structured data such as log files to stream. The collection of data through these convergence would be able to utilize as a basic material of big data analysis.

• Journal of Soil and Groundwater Environment
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• v.12 no.6
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• pp.60-69
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• 2007

Understanding the behavior of gas phase VOCs (volatile organic compounds) in unsaturated soils is of a great environmental importance for public health concerns. Moment analysis for the breakthrough curves (BTCs) during transport of chemicals in porous media was known to be a useful tool to evaluate the velocity, spreadness, and the skewness of the plume of the chemicals. In this study, the temporal moments of the BTCs of a group of VOCs were analyzed for the gaseous transport in an unsaturated soil. BTCs were measured using lab-scale column experiments for four different VOCs at the water saturation range of 0.04-0.46, and for eleven VOCs at a water saturation of 0.21. The central second and third moments of the VOCs were compared with the water saturation and the first moment. It was found that both central second and third moments increased with the first moment. The central third moment was, however, found to be more sensitive to the first moment.

• The KSFM Journal of Fluid Machinery
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• v.18 no.6
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• pp.57-62
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• 2015

The test of comparing liquid flow calibration system (approved by KOLAS) for accuracy and structure change test was performed in the test bed in order to evaluate the typical characteristics of the electromagnetic flow meters and parshall flume that are generally used in the water discharging facilities. The results of the accuracy comparing test with liquid flow calibration system showed the error of less than 2%. Pharshall plume got error up to -8.3% (low flow) from the flow rate test, but less than 4% from the accumulated flow test because of offset error at high flow rate and low flow rate. Evaluation of structual change test was tested with only parshall flume using structure and it consisted of installation angle (parshall flume and level sensor) and position change. Installation angle, water level sensor angle and position changing test for parshall flume had errors of 3.1%~-9.2%, 0.4%~-5.6% and 0.2%~1.3% respectively. Especially, the error showed the largest increase when the water level sensor measured the point of decreased flow by the structure change. Therefore, error factors (change of straight pipe length, installation of obstacle or effect of foreign substances on water level sensor) that can often occur in the field should be derived and the research for optimized installation method should be carried out continuously.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.27-33
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• 2014

2nd stage of KSLV-I, NaRo-Ho, performs CCAM not to collide with Naro Science Satellite. At that moment, the satellite should pass through the Plume Density area which was generated by KSLV-I KM residual thrust. Therefore, it is necessary to predict Plume Density field of KM residual thrust and guarantee the safety of the trajectory of payload. In this paper, DSMC method was used to simulate Plume Density by KM residual thrust and the simulation showed that the trajectory of Naro Science Satellite was safe.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.75-81
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• 2014

The flame deflector should be constructed to minimize the induced environmental effects on the launch vehicle and to minimize the exhaust impingement effects on the launch complex structures during the lift-off operation. Therefore, it should be designed to avoid recirculation and reverse flow of rocket exhaust plumes. The circumstance around launch complex and characteristics of launch vehicle should be taken into consideration for the flame deflector design. In this paper, we designed the flame deflector reflecting KSLV-II 1st engine characteristics and analyzed the effect of exhaust plumes related to change geometry by means of computational flow analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.10-17
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• 2013

This paper describes a study on after-burning suppressant in a solid propellant to reduce the plume formed outside of rocket nozzles, which could expose the launch site and the flight track. The minimum smoke propellant to enhance the stealth ability was formulated in terms of the kinds and the effects of after-burning suppressant on the ballistic performance and the amount of primary smoke. A after-burning suppressant, $K_2SO_4$ of about 1.1% weight content was found to show profound reduction of the rocket plume, giving negligibly slight increase in pressure exponent of burning rate. Also minimum smoke propellant with less than 1.1% of $K_2SO_4$ corresponds to A-class satisfaction in primary smoke by AGARD standard.

• Korean Journal of Optics and Photonics
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• v.30 no.1
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• pp.1-7
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• 2019

MANPADS (man-portable air defense system) is a counterweapon system against enemy aircraft, tracking the MWIR (mid-wavelength of infrared) signature of the plume. Under foggy conditions, however, multiple scattering phenomenon caused by the particles affects the MWIR transmittance, and the MANPADS detection performance. Therefore, in this study we analyzed the lock-on range of MANPADS with varying fog conditions and plume characteristics. To analyze the optical extinction properties and transmittance in fog, Mie scattering theory and analytic solution of the radiative-transfer equation are utilized. In addition, we used flare signature as an alternative MWIR light source. We confirmed that the lock-on range could be noticeably reduced under conditions of mist, and proportional to the flare temperature.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1159-1163
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• 2005

자연하천에서의 유량측정은 직$\cdot$간접유속측정을 통하여 이루어진다. 홍수기는 주로 봉부자에 의한 방법을 이용하고 평$\cdot$갈수기에는 파샬플룸이나 유속계에 의한 방법을 이용한다. 이 방법은 측정지점의 상태 또는 기술자의 숙련도에 따라 많은 오차를 발생시키고 연속적인 관측의 어려움을 가진다. 본 연구는 자연하천의 기본적인 수리학적 정보와 하천의 수리특성을 나타내는 조도계수를 유량규모별로 추정하여 유량을 산정하는 기법을 활용하여 자연하천 유량자료의 연속적인 획득이 가능한 프로그램을 개발하였다. 대상지점으로 금강 대청댐 하류 공주지점을 선정하여 2003년$\~$2004년의 유량실측 자료를 바탕으로 유량 측정하고, 단면의 적절한 조도계수를 추정하여 유량을 산정하였다. 이를 통하여 기존 수위-유량관계곡선식의 신뢰성을 평가하고, 실측값에 근사한 유량을 연속적으로 산정할 수 있도록 하였으며, 이를 적용하여 향후 수문해석, 유출분석등에 활용하고자 한다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.329-332
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• 2004

ZnO thin films were grown with different plume-substrate angles by pulsed laser deposition (PLD) to control the amount of ablated species arriving on a substrate per laser shot. The angles between plume propagation direction and substrate plane (P-S angle) were 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$. The growth time was changed in order to adjust film thickness. From the XRD pattern exhibiting a dominant (002) and a minor (101) XRD peak of ZnO, all films were found to be well oriented along c-axis. From the AFM image, it was found that the grain size of ZnO thin film was increased, as P-S angle decreased. UV intensity investigated by PL (Photoluminescence) increased as P-S angle decreased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.323-326
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• 2006

This paper presents the computational results for the two-dimensional compressible non-reacted flow in a converging-diverging micro thrust nozzle of which the ratio of exit to throat width (0.541 in.) is 1.8. The RNG model is applied to calculate the turbulence by loading the standard coefficients. The results agreed very well with the experiments in the view of the shock structure and the pressure distribution at the various pressure ratios between the stagnation and the environmental states. The plume structures are also discussed on the view of the shock-cell structure.