• Journal of The Korean Astronomical Society
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• v.53 no.5
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• pp.103-115
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• 2020

We analyze the spatially resolved kinematics of gas and stars for a sample of ten hidden type 1 AGNs in order to investigate the nature of their central sources and the scaling relation with host galaxy stellar velocity dispersion. We select our sample from a large number of hidden type 1 AGNs, which are identified based on the presence of a broad (full width at half maximum ≳1000 km s^-1) component in the Hα line profile and which are frequently mis-classified as type 2 AGNs because AGN continuum and broad emission lines are weak or obscured in the optical spectral range. We used the Blue Channel Spectrograph at the 6.5-m Multiple Mirror Telescope to obtain long-slit data with a spatial scale of 0.3 arcsec pixel^-1. We detected broad Hβ lines for only two targets; however, the presence of strong broad Hα lines indicates that the AGNs we selected are all low-luminosity type 1 AGNs. We measured the velocity, velocity dispersion, and flux of stellar continuum and gas emission lines (i.e., Hβ and [O III]) as a function of distance from the center. The spatially resolved gas kinematics traced by Hβ or [O III] are generally similar to the stellar kinematics except for the inner center, where signatures of gas outflows are detected. We compare the luminosity-weighted effective stellar velocity dispersions with the black hole masses and find that our hidden type 1 AGNs, which have relatively low back hole masses, follow the same scaling relation as reverberation-mapped type 1 AGN and more massive inactive galaxies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.675-683
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• 1992

Mapping and navigation system based on certainty grids for an autonomous mobile robt operating in unknown and unstructured environment is described. The system uses sonar range data to build a map of robot's surroundings. The range data from sonar sensor are integrated into a probability map that is composed of two dimensional grids which contain the probabilities of being occupied by the objects in the environment. A Bayesian model is used to estimate the uncertainty of the sensor information and to update the existing probability map with new range data. The resulting two dimensional map is used for path planning and navigation. In this paper, the Bayesian updating model which was successfully simulated in our earlier work is implemented on a mobile robot and is shown to be valid in the real world through experiment. This paper also proposes a technique for reducing for reducing specular reflection problem of sonar system which seriousely deteriorates the map quality, and a new path planning method based on weighted distance, which enables the robot to efficiently navigate in an unknown area.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.589-598
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• 2018

To maintain safety and reliability of reactors, redundant sensors are usually used to measure critical variables and estimate their averaged time-dependency. Nonhealthy sensors can badly influence the estimation result of the process variable. Since online condition monitoring was introduced, the online cross-calibration method has been widely used to detect any anomaly of sensor readings among the redundant group. The cross-calibration method has four main averaging techniques: simple averaging, band averaging, weighted averaging, and parity space averaging (PSA). PSA is used to weigh redundant signals based on their error bounds and their band consistency. Using the consistency weighting factor (C), PSA assigns more weight to consistent signals that have shared bands, based on how many bands they share, and gives inconsistent signals of very low weight. In this article, three approaches are introduced for improving the PSA technique: the first is to add another consistency factor, so called trend consistency (TC), to include a consideration of the preserving of any characteristic edge that reflects the behavior of equipment/component measured by the process parameter; the second approach proposes replacing the error bound/accuracy based weighting factor ($W^a$) with a weighting factor based on the Euclidean distance ($W^d$), and the third approach proposes applying $W^d$, TC, and C, all together. Cold neutron source data sets of four redundant hydrogen pressure transmitters from a research reactor were used to perform the validation and verification. Results showed that the second and third modified approaches lead to reasonable improvement of the PSA technique. All approaches implemented in this study were similar in that they have the capability to (1) identify and isolate a drifted sensor that should undergo calibration, (2) identify a faulty sensor/s due to long and continuous missing data range, and (3) identify a healthy sensor.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.129-139
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• 2010

This study proposes a model for measuring the connectivity of nodes in road networks. The connectivity index between two nodes is characterized by the number of routes, degree of circuitousness, design speed, and route capacity between the nodes. The connectivity index of a node is then defined as the weighted average of the connectivity indexes between the node and other nodes under consideration. The weighting factor between two nodes is determined by the travel demand and distance between them. The application of the model to a toy network shows that it reasonably well quantifies the level of connectivity of nodes in the network. If flow of rail networks can be measured in the same scale as that of road networks and the capacity of rail links can be estimated, the model proposed in this paper could be applied to intermodal transportation networks as well.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.538-550
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• 2008

Radon is an invisible, odorless, and radioactive gas. It is formed by the disintegration of radium, which is a decay product of uranium. Some amounts of radon gas and its products are present ubiquitously in the soil, water, and air. Particularly high radon levels occur in regions of high uranium content. Although radon is permeable into indoor environment not only through geological features (bed rock and permeability) but also through the construction materials and underground water, the radiation from the geological features is generally main exposure factor. So there can be a problem in a certain space such as the underground and/or relatively poor ventilation condition. In this study, a GIS technique was used in order to investigate spatial distribution of radon measured from sub- way stations of 1 thru 8 in Seoul, Korea in 1991, 1998, 2001, and 2006. Spatial analysis was applied to reproduce the radon distribution. We utilized spatial analysis techniques such as inverse distance weighted averaging (IDW) and kriging techniques which are widely used to relate between different spatial points. To validate the results from the analyses, the jackknife technique for an uncertainty test was performed. When the number of measuring sites was less than 100 and also when the number of omitted sites increased, the kriging technique was better than IDW. On the other hand, when the number of sites was over 100, IDW technique was better than kriging technique. Thus the selection of analytical tool was affected sensitives by the analysis based on the number of measuring sites.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.610-618
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• 2013

The damaged district by flooding has been changed from mainly farmland to cities due to the weather phenomena which is different from the past. This has caused not only irreparable damage of people's lives and property but social infrastructures. There also exist serious damages such as isolation of drivers and traffic jam as the roads were flooded. In this study, we suggested a method to develop a flood risk index focused on not Si, Gun or Gu but roads. In addition, flood risk index in the roads just at the moment, when it rains quantitatively, will be provided by using real-time rainfall information provided by the Weather Center. Then it should be helpful to prevent people from being isolated by flooded roads in advance.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.379-379
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• 2011

본 연구는 우리나라 전국 기상관측소 중 1973년부터 2009년까지의 시 강수자료가 구축되어 있는 기상관측소 55개 지점에 대하여 비정상성 빈도해석을 수행하였다. 각 지점에 대하여 지속시간 1시간, 24시간에 대한 연 최대 강수량 자료를 구축하여 초기 20년을 기준으로 1년씩 추가한 연 최대 강수량 누적 자료를 생성하고, 생성된 기간별 자료의 평균, 위치매개변수, 축척매개변수를 산정하였으며, 위치매개변수와 축척매개변수는 확률가중모멘트법을 사용하여 산정하였다. 산정된 연 최대 평균 누적 강수량과 연도와의 선형 회귀식을 산정하여 목표연도별(2040, 2070, 2100년) 평균 강수량을 산정하였고, 위치매개변수와 축척매개변수도 평균 누적 강수량과의 선형 회귀식을 산정함으로써, 목표연도에 해당하는 각 매개변수를 산정하였다. 또한 산정된 목표연도별 평균 강수량, 위치매개변수와 축척매개변수를 이용해 확률강수량을 산정하였다. 비정상성 빈도해석을 수행하여 산정된 55개 지점에 대한 목표연도별 확률강수량을 Inverse Distance Weighted(IDW) 보간법을 사용하여 전국의 확률강수량을 공간적으로 표현하였다. 전국단위의 비정상성 빈도해석을 실시한 결과, 전체적으로 각 목표연도별 확률강수량이 증가하는 것으로 나타났으나, 일부 감소하는 지역도 나타났다. 경기도와 강원도 등 중부지역에서 확률강수량의 증가가 큰 것으로 나타났으며, 특히 강원도(강릉, 인재 등) 지역에서 확률강수량의 증가폭이 가장 크게 나타났다. 또한 남해지역에서는 대부분 확률강수량이 감소하는 것으로 나타났고, 그중에서 전라남도 남해안 부근(장흥 등)에 확률강수량의 감소가 가장 크게 나타났으며, 경북지역과 전북지역 부근에서는 증가 또는 감소의 차이가 미비하게 나타났다. 하지만 목표연도 2070년과 2100년에 대하여 산정된 확률강수량으로부터 선형 회귀식을 통해 목표연도별 평균 강수량, 위치매개변수, 축척매개변수를 추정하여 확률강수량을 산정하는 것에 한계가 있음을 보여주었다.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.189-197
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• 2011

This paper reviewed application of data-driven method, distance-weighted method(IDWM, IEWM, CCWM, ANN), and radar data method estimated of missing raifall data. To evaluate these methods, statistics was compared using radar and station rainfall data from Imjin-river basin. The range of RMSE values calculated for CCWM, ANN was 1.4 to 1.79mm, and the range of RMSE values estimated data used for radar rainfall data was 0.05 to 2.26mm. Spatial characteristics is considered to Radar rainfall data rather than station rainfall data. Result suggest that estimated data used for radar data can impove estimation of missing raifall data.

• The Journal of Engineering Geology
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• v.8 no.3
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• pp.235-245
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• 1998

Adquate friction resistance is needed to prevent pavement slipperiness and to allow vehicles to stop in a reasonable distance. Performance of the aggregates is reduced over time by wear and polishing as a consequence of vehicular traffic. In this research, the objective was to develop a laboratory method to test Indiana gravel aggregates to predict field performance, and determine causes for the range of values amang gravel aggregates. The assessment of gravel sources was primarily on the basis of individual rock types and those proportions comprising the gravel. Polish and friction values were determined in the laboratory with the British Wheel and Pendulum. The gravels of this study were composed primarily of carbonate aggregates that showed considerable variability in polishing thresholds. Igneous and metamorphic constituents polished to a lesser degree and are expected to improve overall aggregate performance. Estimates of the IFV (Initial Friction Value) and PV (Polished Value) for crushed gravel samples can be made based on the percentage of rock types present in the sample. A weighted average is used to make this calculation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.1947-1953
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• 2012

The vehicle fuel economy is very important issue in the view of global warming. This paper proposes the three fuel economy improvement algorithms which predict the velocity using altitude data of the positions in front of vehicle and estimates their performances. The proposed 3 algorithms are WMGA(Weighted Mean Gradient Angle), RAADE I, II(Reacceleration After Deacceleration I, II). This research extracts the distance and altitude data from received GPS data and calculates gradient angle and road load for each section. The velocity profile according to proposed algorithms is made for Youngdong highway of 213km. And the test vehicle runs along this highway and fuel economy is measured. RAADE II of proposed algorithms showed better performance by 3.571% in comparison to the conventional CVELCONT3.