• KSBB Journal
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• v.10 no.4
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• pp.441-448
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• 1995

Optimized fermentation medium and cultural conditions for the production or exopolysaccharide KS-1 with Bacillus polymyxa KS-1 was following as; 30g g1ucose, 2.59g yeast extract, $2.5g KH_2PO_4, 0.5g NaCl, 0.3g MgSO_4.7H_20, 0.1g CaC0_3 0.05g, FeSO_4.7H_2O, and 0.05g MnS0_4 . 4H_20in 1 liter distilled water. The exopolysaccharide production was influenced by the by the temperature and pH, the optimal conditions for the production of exopolysaccharide KS-1 seemed to be $30^{\circ}C$ and pH 7.0, respectively. About $10.3g/\ell$ of maximum exopolysaccharide was obtained al the initial pH 7.0, $30^{\circ}C$, 2vvm of aeration rate and 400 rpm of impeller speed in a jar fermentor.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1513-1518
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• 2012

This paper is implemented media transmission system of VLC transmitter and receiver module using LED of White lighting that is based on PC module and to transmission technology for performance analysis. To realize LED visible light communication receiver is used 1~12 LED light-emitting device and transmitter is used a variable sensor. Developed initial distance of the tranceiver is more than 0~1m for LED VLC and the overall system transmission speed is achieved on variable having Visible light media transmission system. Composition to PC module with LED module and infrared sensor for performance analysis, predict and analyze the communication distance, check about the possibility of application methods. Measure each performance when the lens wearing and not wearing in order to increase the overall efficiency of the LED module, can know that increase efficiency of approximately 20%.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.37-50
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• 2007

This study investigated the characteristics of spray generated by a liquid coaxial swirl injector used in a combustor of the liquid rocket engine. The linear stability analysis considered long and short wave was introduced in liquid sheet breakup. Through the hydrodynamic analysis the initial liquid sheet thickness spray angle and injection velocity were predicted. To evaluate the effect of turbulence model standard $k-{\varepsilon}$ and RNC $k-{\varepsilon}$ model were applied to numerical calculation and it was known that RNC $k-{\varepsilon}$ model was more applicable to predict spray characteristics. On the basis of this evaluation validation of the developed model was performed with swirl injector installed in LPRE and the predicted results of breakup length, spray angle, and SMD agreed well with experiments qualitatively and quantitatively.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.247-247
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• 2019

수력발전 사업에 있어 Desander 구조물은 주로 고산지대 수력발전댐의 Run-of-river 형식의 발전방식에서 유사로 인한 터빈의 손상을 방지하기 위한 목적으로 설치된다. Desander의 적정 규모는 터빈의 손상을 일으킬 수 있는 유사 입경에 대해 안정적으로 침전을 시킬 수 있는 폭/길이/깊이로 평가할 수 있으며 상대적으로 Desander의 규모가 크게 설계된 경우 초기 공사비 증가하고 반대로 규모가 작게 설계된 경우 터빈의 교체 주기 단축으로 인한 유지관리비가 증가된다. 현재까지 일반적인 Desander 구조물의 설계 방식은 제거 입경의 침전 속도, 유입유량 및 깊이를 변수로 사용하여 경험식(L. Sudry method, Guicciardis method 및 Rouse method)을 통해 규모를 결정해 왔다. 하지만, 3-D 전산유체해석을 통해 유속 흐름 분석으로 직 간접적 Desander 규모의 적정성을 평가할 수 있는 현 시점에서 경험식으로부터 도출된 결과의 신뢰성과 객관성을 검증할 필요가 있다고 판단된다. 본 연구에서는 노르웨이 NSTU에서 개발한 유사의 이송 및 확산해석 기능이 내장된 범용 소프트웨어인 SSIIM을 이용하였다. SSIIM(Simulation of Sediment movements In water Intakes with Multiblock)은 개수로 흐름 상태에서 유사 이동 및 하상 변동을 분석할 수 있도록 개발된 3-D 해석 프로그램이다. SSIIM은 수치해석 방법으로 유한체적법(Finite Volume Method)를 채택하였으며 Navier-Stokes equations을 통해 유체의 흐름을 해석한다. 입력 자료는 유입 유량($m^3/sec$), 유입 유사량(kg/sec), 유출부 수위 및 해당 Desander Structure grid 자료가 사용되며 해석 결과로 Desander 내 grid 별 유속, 수위, 유사 농도 변화 등을 제공한다. 본 연구에서는 SSIIM을 이용하여 제거 목표 유사 입경의 차집 효율(Trap efficiency)로 Desander의 적정 규모를 평가 할 수 있는 설계법을 제안하며 설계 단계에서 결정되는 최소 제거유사 입자와 차집 효율에 의한 Desander의 적정 규모 평가 분석을 파키스탄 A 프로젝트를 대상으로 수행하였다. 연구 성과로 (1)SSIIM을 통해 해석된 차집 효율을 기초로 Desander의 적정 규모를 계획할 경우 경험적 방식에 비해 설계의 객관성과 신뢰성을 제고할 수 있으며 (2)3-D 수치해석을 통해 grid 별 유사농도를 확인 할 수 있어 Desander 형상과 규모에 대한 평가가 가능하다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.541-548
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• 2019

In this paper, the required amount of heat for an anti-icing system of a Flush Air Data Sensing(FADS) system is predicted. For an efficient prediction during the early stage of a design process, a handbook method is used. A program of which inputs are flight conditions is developed to predict the required amount of heat. A CFD analysis is conducted to compute the water catch efficiency which is one of the core parameters used in the handbook method. Kriging method, one of well-known regression mothods, is utilized to construct a surface contour database to evaluate impingements of droplets. To predict the trajectories of droplets, the database of a flow field around the surface is built using Kriging method as well.

• Journal of Platform Technology
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• v.9 no.3
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• pp.44-51
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• 2021

In general, golden time refers to the most important time in the initial response to accidents such as saving lives or extinguishing fires. The golden time varies from disaster to disaster, but is aimed at five minutes in terms of fire and first aid. However, for the actual site, the average dispatch time for ambulances is 9 minutes and the average transfer time is 17.6 minutes, which is quite large compared to the golden time. There are various causes for this delay, but the main cause is traffic jams. In order to solve the problem, the government has established emergency car concession obligations and secured golden time to prioritize ambulances in places with the highest accident rate, but it is not a solution in rush hour when traffic is increasing rapidly. Therefore, this paper proposed a deep learning-based emergency vehicle priority signal system using collected sound data by installing sound sensors on traffic lights and conducted an experiment to classify frequency signals that differ depending on the distance of the emergency vehicle.

• The Journal of Engineering Geology
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• v.15 no.3
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• pp.245-255
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• 2005

Three dimensional Monte-Carlo simulations of non-ergodic transport of a non-reactive solute plume by steady-state groundwater flow under a uniform mean velocity in isotropic heterogeneous aquifers were conducted. The log-normally distributed hydraulic conductivity, K(x), is modeled as a random field. Significant efforts are made to reduce the simulation uncertainties. Ensemble averages of the second spatial moments of the plume, $$lt;S_{ij}'(t',l')$gt;$ and plume centroid variances, $$lt;R_{ij}'(t',l')$gt;$ were simulated with 3200 Monte Carlo runs for three variances of log K, $\omega^2_y1.0,,2.5,$ and 5.0, and three dimensionless lengths of line plume sources ( l=,5 and 10) normal to the mean velocity. The simulated second spatial moment and the plume centroid variance in longitudinal direction fit well to the first order theoretical results while the simulated transverse moments are not fit well with the first order results. The first order theoretical results definitely underestimated the simulated transverse second spatial moments for the aquifers of large u: and small initial plume sources. The ergodic condition for the second spatial moments is far from reaching, and the first order theoretical results of the transverse second spatial moment of the ergodic plume slightly underestimated the simulated moments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.698-703
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• 1996

To elucidate the proper nitrogen application method for machine transplanting of rice infant seedling in no-tilled paddy, Dongjinbyeo was used and nitrogen was applied five methods including conventional application method. Leaf color was darker at 80% of total nitrogen was applied as basal and lighter at 20% of total nitrogen was reduced than conventional application method in tillering stage, but wasn't significantly different after panicle formation stage among the application method. And it was thinner at tillering stage and was darker after panicle formation stage in no-tilled paddy compared with tilled paddy. Tiller number, LAI and top dry weight were more at 80% of total nitrogen was ap-plied as basal than conventional application method, and more in tilled paddy than no-tilled one at tillering stage, but at heading stage they were highest at top dressing applied 25 days after transplanting. C.G.R was highest at top dressing for tillering was delayed and it was lower in no-tilled paddy at tillering stage but was higher after panicle formation stage than in tilled one. Yield was highest at top dressing time was delayed among nitrogen application method, but wasn't significantly different between tilled method in same nitrogen application method.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.79-84
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• 1992

The Photosynthetic bacterium, Rhodopseudomonas sphaeroides strain B6 was irnmobilized on agar gel. The optimum concentration of agar for hydrogen production was 2% (w/v). Maximum rates of hydrogen production by immobilized (300 ml of gel; 2.85 rng dry cells/ml) and free cells (1l culture; 0.87 mg dry cells/ml) were 47.5 and 48.0 ml/hr/culture, respectively. However, when both cultures were fed by 10 mmoles of lactate as limited electron donor at the later period of incubation, the activity of hydrogen production by free cells was significantly decreased but, immobilized cells continued hydrogen production with almost the same initial rate. Wc examined hydrogen production by immobilized cells of strain B6 under periodic illumination for 12 hr-intervals. When the culture was periodically fed by basal medium containing 9.3 rnmoles of DL-lactate and 1.86 mmoles of L-glutamate as consumed electron donor and nitrogen source, respectively, for every one liter of hydrogen produced, hydrogen was evolved continuously with the average rate of 510 ml/day/300 ml gel (2.9 rng dry cellslml) during the incubation time for 228 hr.

• Journal of the Korean earth science society
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• v.36 no.6
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• pp.520-532
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• 2015

In order to understand the Holocene sea level changes in the eastern Yellow Sea, the west coast of Korea, and to compare the rates of sea level rise in each period of time, the geological proxy records for pre-instrumental era and measurement data for the present day were combined and analysed. The sea level in the Yellow Sea rose fast with a rate of about 10 mm/yr during the early Holocene, and decelerated down to 1 mm/yr since the mid to late Holocene. The rising rates of sea level in the 20th century were slightly higher than those in the late Holocene. The present-day rates of sea level rise, known as the 'rapid' rise, are in fact much lower or similar, compared to the early to mid Holocene sea levels in the study area. Recent tide-gauge data show that sea level rise in the eastern Yellow Sea has been accelerating toward the 21st century. These rising trends coincide well with global rising patterns in sea level. Additionally, the present-day rising trends of sea level in this study are correlated with increased rates of carbon dioxide concentrations and sea surface temperatures, further indicating a signal to global warming associated with the human effect. Thus, the sea level changes induced by current global warming observed in the eastern Yellow Sea and world's oceans can be considered as 'Anthropocene' sea level changes. The changes in sea level are based on instrumental measurements such as tide-gauges and satellite altimetry, meaning the instrumental era. The Holocene changes in sea level can thus be reconstructed from geological proxy records, whereas the Anthropocene sea-level changes can be solely based on instrumental measurements.