• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.129-132
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• 2010

Users can obtain useful information from large of data because of development of internet. Since these data rise continuously like stream data, it is required to extract the appropriate information efficiently for the user's needs. In the traditional scheme, they are acquired by processing the user queries after the occurred data are stored at a database. However, it is inefficient to process the user queries over the large volume of continuous data by using the traditional scheme. In this paper, we propose the Event-Profile Model to define the data occurrence on the internet as the events and the user's requirements as the profiles. We also propose and implement the filtering scheme to process the events and the profiles efficiently. We evaluate the performance of the proposed scheme and our experiments show that the new scheme outperforms the other on various dataset.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1750-1755
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• 2011

Recently, it is possible for users to acquire necessary data easily as the various schemes of the searching information are developed. Since these data rise continuously like stream data, it is required to extract the appropriate data for the user's needs from the mass data on the internet. In the traditional scheme, they are acquired by processing the user queries after the occurred data are stored at a database. However, it is inefficient to process the user queries over the large volume of continuous data by using the traditional scheme. In this paper, we propose the Event-Profile Model to define the data occurrence on the internet as the events and the user's requirements as the profiles. We also propose and implement the filtering scheme to process the events and the profiles efficiently. We evaluate the performance of the proposed scheme and our experiments show that the new scheme outperforms the other on various dataset.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.12
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• pp.3360-3371
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• 1995

Hydrodynamic characteristics of a stratified flow at a Y-junction were examined analytically. Gas is supplied through the main horizontal channel and liquid is introduced into the gas stream from the Y-shaped bottom branch. Analysis was performed with irrational flow and inviscid fluid assumptions. The Stokes' inverse transformation technique was adopted to convert the real x-y plane into the x-.psi. plane. The potential flow equation was solved numerically in the transformed (x-.psi.) plane and the interface profile, pressure distribution and the streamlines were obtained. The effects of the inlet conditions, injection angle and the gravity on the flow characteristics were also examined. To check the validity of the present method, the previous resultant the two-dimensional obtuse wedge flow was compared. The inverse transformation technique turned out to be also very useful to predict the hydrodynamic characteristics of a stratified flow with the pressure variation at a Y-shaped mixing junction.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.51-56
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• 2006

Biases embedded in numerical weather precipitation forecasts by the RDAPS model was determined, quantified and corrected. The ultimate objective is to eventually enhance the reliability of reservoir operation by Korean Water Resources Corporation (KOWACO), which is based on precipitation-driven forecasts of stream flow. Statistical post-processing, so called MOS (Model Output Statistics) was applied to RDAPS to improve their performance. The Artificial Neural Nwetwork (ANN) model was applied for 4 cases of 'Probability of Precipitation (PoP) for wet and dry season' and 'Quantitative Precipitation Forecasts (QPF) for wet and dry season'. The reduction on the large systematic bias was especially remarkable. The performance of both networks may be improved by retraining, probably every month. In addition, it is expected that performance of the networks will improve once atmospheric profile data are incorporated in the analysis. The key to the optimal performance of ANN is to have a large data set relevant to the predictand variable. The more complex the process to be modeled by the ANN, the larger the data set needs to be.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.1-3
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• 2007

• Annual Conference of KIPS
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• 2001.04b
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• pp.1089-1092
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• 2001

IDS 에서 가장 중요한 것은 침입을 논리적으로 모델링하고, 이것을 센싱 할 수 있는 Filter 의 개발이며 Filter 에서 발생한 이벤트들에서 특정 공격 행위를 인식할 수 있는 신호인 Signature 의 정의를 통해 이벤트 스트림에서 Signature 를 자동으로 인식할 수 있는 방법에 대한 연구가 가장 핵심적이라고 할 수 있다. 본 논문은 이러한 filter 와 Signature 에서 사용할 수 있도록 특징들이 정의 되어있는 양식으로 원시 데이터로부터 profile 을 생성 filter 와 signature 에서 탐지할 수 있는 모듈을 적용할 수 있도록 네트웍과 host input stream 등의 raw audit data 에서 특징을 추출 Feature Construction 작성에 대한 연구이다.

• 한국가시화정보학회:학술대회논문집
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• 2004.12a
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• pp.157-168
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• 2004

The effects of pulsation in a pulsating flow through a rectangular channel have been investigated by Particle Image Velocimetry in both laminar and turbulent flow conditions. PIV results on a square channel (aspect ratio:1) have been reported on the cases of Reynolds number Re=80 in laminar and Re=8800 in turbulent region. For both in the laminar and turbulent regions, the influence of the pulsation onto the magnitude changes of the average velocity was negligible. In the turbulent region, the magnitude profiles of the stream-wise pulsating component obtained by the theoretical analysis based on the Stokes analogy were slightly different from the experimental ones due to the influence of the turbulent viscosities onto the pulsating flows.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.2
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• pp.112-117
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• 1990

Boussinesq-type equations should be employed in which the water surface profile is considerably steep or the bottom topography is abruptly changed. The primary reason is that the pressure deviates significantly from the hydrostatic pressure distribution due to the large curvature of the stream lines. It is shown that such a Boussinesq type equation can be also derived by making use of the concept of the averaged flow description for specifying the turbulence effects. In addition, a numerical scheme is developed to solve the equations and the effects of the Boussinesq term is briefly investigated.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.19-35
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• 1997

The purpose of this study is to find out the characteristics of landform in Geoje-Do using GIS and DTED data. The characteristics of landform in Geoje-Do are as follows; First, the height-range of Geoje-Do is $0{\sim}580m$, and the average elevation of it is 124m. Volcanic and granite region is mainly appeared at high elevation-region. But, we can't find out outstanding difference of elevation, according to its geology. The second. the slope-range of Geoje-Do is $0{\sim}52$ degree, and the average slope of it is 17.6 degree. The slope of volcanic and granite area is more steeper than any other region. But the results of analysis of the geology in Geojo-Do, don't show outstanding difference of the slope. The third, the area-rate of the aspect of Geoje-Do is almost same in all direction. And the area-rate of south-west direction is the highest. According to the geology of Geoje-Do, granite is distributed the most widely, and the area of volcanic and granite occupy 60% of entire island's area. According to analysis of influence of geology with elevation, geology has little relationship with elevation. According to analysis of geology and drainage network, streams are inclined to be developed well in Alluvium area. Drainage network is well developed throughout the entire island, except southeast area. The highest order of stream is 4 in 1:25,000 topographic map. The density of stream in Geoje-Do is very high, such as 1.6. The bifurcation-ratio of stream is also higher than 4 in all order. The length-ratio of stream is ranged from 1.24 to 3.25. According to the relationship between order and elevation. order is the greater, elevation is the lower. According to the relationship between order and slope, order is the greater, slope is the gentler. In this study, we use DTED Data, and compare it with topographic map data. According to the comparison, there is a little difference between DTED data and topographic map data. Therefore, to use DTED data in landform analysis, it is required coordinate matching process. This process is very important, and take very long time. Thus, if you use DTED in landform analysis, some processes are required. DTED data can be taken very easily, but its using is not simple. Because coordinate adjust is very hard work.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.4
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• pp.847-864
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• 1988

The main purpose of this study is to investigate the local velocity acceleration in a boundary layer diffusion flame over a flat plate. In order to know the effect of separation on the local velocity acceleration, two typical cases, flows with and without separation, are considered. For these cases, flow visualization using paraffine smoke tracers has been made. Mean velocity and r.m.s. value of fluctuating velocity are measured by using a laser Doppler velocimeter. In addition, measurements of time-mean concentration and time-mean temperature have been made. Time-mean density profiles have been obtained from the data of concentration and temperature. The obtained results are summarized as follows : (1) In the case without separation, the local velocity acceleration is clearly observed near the visible flame zone for all flow conditions. On the while, in the case with serration, the local velocity acceleration is observed only at low free stream velocity and high fuel injection velocity. As increasing the free stream velocity or decreasing the fuel injection velocity, it is not distinctly observed in the mean velocity profile. (2) The r.m.s. value of fluctuating velocity is significantly decreased by combustion in the case with separation. But in the case without separation, the r.m.s. value is increased near the visible flame zone in comparison with cold flow. In both cases, the peak value of r.m.s. appeared just at the visible flame zone, where the mean velocity gradient is not too high.