• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.74-83
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• 2007

The goal of this study is to establish an integrated watershed hydrologic model for the whole Nakdong River basin whose area is an approximately 24,000 km2. Including a number of watershed elements such as rainfall, runoff, water use, and so on, the proposed model is based on SWAT model, and is used to improve the flow duration curve estimation of ungauged watersheds for Korean Total Maximum Daily Load (TMDL). The model is also used to recognize quantitatively the river flow variation due to water use elements and large dam effluents in the whole watershed. The established combined watershed hydrologic model, SWAT-Nakdong, is used to evaluate the quantified influences of artificial water balance elements, such as a dam and water use in the watershed. We apply two water balance scenarios in this study: the dam scenario considering effluent conditions of 4 large multi-purpose dams, Andong dam, Imha dam, Namgang dam, and Habcheon dam, and the water use scenario considering a water use for stream line and the effluent from a treatment plant. The two scenarios are used to investigate the impacts on TMDL design flow and flow duration of particular locations in Nakdong River main stream. The results from this study will provide the basic guideline for the natural flow restoration in Nakdong River.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2302-2304
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• 1999

The application of polymeric insulators for outdoor use has been increasing as a new replacement of overhead line in abroad. In domestic case, it is actively going on the research of polymeric insulators. The Silicone rubber among polymeric insulators have a good electrical properties, due to surface hydrophobicity. This paper is concentrated on the recovery of surface hydrophobicity and the change of surface construction after electrical stress. The feature of silicone rubber, a good hydrophobicity, is demanded the improvement method as the estimation of the non-ceramic insulators like it.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.70.4-71
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• 2016

The links between super-massive black hole masses and their host galaxy properties are observed, indicating that black hole growth and host galaxy evolution are closely related. Reverberation mapping, which uses the time delay from the central black hole to broad line regions, is one of the best methods to estimate masses of black holes of active galactic nuclei (AGNs). However, only masses of about 50 black holes have been determined in reverberation mapping studies so far, and most of them are limited to optical luminosities below 10^45 erg/s due to the challenges of long-term time domain observations in both photometry and spectroscopy. In this project, we expand reverberation mapping samples to higher luminosities of > 10^44.5 erg/s at 0.1 < z < 0.35, that have expected time lags of 40 - 250 light days. Photometric (using LOAO 1-m and MDM 1.3-m) and spectroscopic (using MDM 2.4-m and Lick 3-m) monitoring campaigns are being conducted for a 3 year duration and 20 day cadence. Precedent photometric observations in 2015B show some targets with variability and follow-up spectroscopic observations are on-going. In this presentation, we introduce our project, present reverberation mapping simulation results, and preliminary results on photometry. These reverberation mapping masses of relatively high luminous AGNs will provide a strong constraint on black hole mass calibration, e.g., the single-epoch mass estimation.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.237-239
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• 2018

This paper proposes an on-line estimation algorithm of internal resistance of Li-ion battery based on the recursive least squares method to prevent the overvoltage and undervoltage casing degradation of life cycle of battery. An equivalent circuit model with single time constant is adopted, and under assumptions that the terminal voltage, current and SOC are measured accurately, the discrete time based nonlinear equation of the model can be converted to the linear equation which can be applied to recursive least squares method. Since the coefficients of the discrete time linear equation can be expressed by the parameters of the equivalent circuit model, it is shown that an internal resistance (Ri) can be estimated in real time using the least square method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.261-279
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• 2023

In this article, the uplink achievable rate is investigated for massive multiple-input multiple-output (MIMO) under correlated Ricean fading channel, where each base station (BS) and user are both deployed multiple antennas. Considering the availability of prior knowledge at BS, two different channel estimation approaches are adopted with and without prior knowledge. Based on these channel estimations, a two-layer decoding scheme is adopted with maximum ratio precoding as the first layer decoder and optimal second layer precoding in the second layer. Based on two aforementioned channel estimations and two-layer decoding scheme, the exact closed form expressions for uplink achievable rates are computed with and without prior knowledge, respectively. These derived expressions enable us to analyze the impacts of line-of-sight (LoS) component, two-layer decoding, data transmit power, pilot contamination, and spatially correlated Ricean fading. Then, numerical results illustrate that the system with spatially correlated Ricean fading channel is superior in terms of uplink achievable rate. Besides, it reveals that compared with the single-layer decoding, the two-layer decoding scheme can significantly improve the uplink achievable rate performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2094-2105
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• 1994

This paper contains a Hough transform based projection method derived from Radon transform for tracking dim unresolved(sub-pixel) moving targets that move along straight line parths across a time sequential image data. In contrast to several recently presented Hough transform methods using a compressed image referred to as the track map our proposed technique utilizing a set of projections taken along arbitrary orientations effectively increases the changes of target detection, and creates a robust track estimation environment by incorporating all the available knowledge obtained from the projections. Moreover, in order to quantitatively assess the estimation capability of the projection-based Hough transform algorithm, the analytical bounds on the Hough space parameter errors introduced by image space noise contamination are derived. The simulation yielded promising results of estimating the track parameters even under low signal to noise rations when our technique was tested against the time sequential sets of real infrared image data referred to as the HiCamps.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.790-795
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• 2011

When railway crossing is required to be improved to improve road traffic efficiency, cost-benefits analysis is conducted. In the analysis, such benefits as the reduction of the delay in road vehicle traffic and related costs and reduction of traffic accidents have been appropriately estimated, however, which has not been the case for the reduction of railway operation costs and accidents. This omission may result in a significant difference in the total estimation of the benefits achievable in a long railway line where many of the crossings are improved or reconstructed. This would deteriorate the rationality of the benefit analysis. As the result, although there are various, significant benefits recognizable in the improvement of railway crossings, but they have not been included in the list of the benefits due to the difficulty in calculation. To this end, this paper proposes a methodology of the calculation of the benefits of railway crossing improvement by estimating the unit costs used in the estimation of the benefits obtainable by the reduction of the railway operation costs and the reduction of the accidents at a crossing on the basis of past studies and data.

• Journal of the Korean Geotechnical Society
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• v.36 no.11
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• pp.51-60
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• 2020

Estimation of passive earth pressure is an important factor in anchor block, temporary retaining wall and support block of raker that resist lateral earth pressure. In practice, due to ease of use, it is common to estimate the earth pressure using the theory of Coulomb and Rankine, which assumes the failure plane as a straight line. However, the passive failure plane generated by friction between the wall surface and the soil forms a complex failure plane: a curve near the wall and a flat plane near the ground surface. In addition, the limit displacement where passive earth pressure is generated is larger compared to where the active earth pressure is generated. Thus, it is essential to calculate the passive earth pressure that occurs at the allowable displacement range in order to apply the passive earth pressure to the design for structural stability reasons. This study analyzed the mobilized passive earth pressured to various displacement ranges within the passive limit displacement range using the semi-empirical method considering the complex failure plane.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.61-69
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• 2010

This paper presents an efficient object selection algorithm by analyzing and detecting of human activity. Generally, when people point any something, they will put a face on the target direction. Therefore, the direction of the face and fingers and was ordered to be connected to a straight line. At first, in order to detect the moving objects from the input frames, we extract the interesting objects in real time using background subtraction. And the judgment of movement is determined by Principal Component Analysis and a designated time period. When user is motionless, we estimate the user's indication by estimation in relation to vector from the head to the hand. Through experiments using the multiple views, we confirm that the proposed algorithm can estimate the movement and indication of user more efficiently.

• Journal of Environmental Health Sciences
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• v.43 no.1
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• pp.55-63
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• 2017

Objectives: This study estimated the emission quantity of benzo(a)pyrene(BaP) produced by fuel combustion in the Seosan area, and analyzed the uncertainty regarding the emissions. Methods: It was based on data from a national agency and from public institutions. Emissions were estimated by using national-level guidelines. The total estimated emissions were analyzed by performing Monte Carlo analysis. Results: The full emission quantity of BaP which was discharged by fuel combustion in the Seosan area stood at 1,194.79 g/yr. The point source emissions came to 184.16 g/yr (95% CI; 158.40-209.39). The line source emissions reached 315.33 g/yr (95% CI; 284.99-344.03). The area source emissions accounted for 695.31 g/yr (95% CI; 605.10-793.88). Chemical and compound manufacturing was the highest with 639.13 g/yr (95% CI; 542.95-728.24) in terms of emissions and oil refinery emissions were high with 153.10 g/yr (95% CI; 129.19~177.46). It was found in the Seosan area that the major source of BaP is the manufacturing of chemicals and chemical products. Conclusion: The emission quantity of BaP which was discharged by the fuel combustion in Seosan area reached 1,194.79 g/yr. Research needs to be continued for the definite estimation of emission of BaP henceforth.