• Journal of Mechanical Science and Technology
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• v.20 no.8
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• pp.1224-1231
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• 2006

The stability and control derivatives of DURUMI-lI UAV using the flight test are obtained. The flight test data is gathered from the normal flight condition (normal mode) and the flight condition assumed as the right elevator fixed (fault mode). Using real-time parameter estimation techniques, applied to Fourier transform regression method, simulates the aircraft motion. From the result, the fault of control surface is to be detected. In this paper, the results of the real- time parameter estimation techniques are compared with the results of the Advanced Aircraft Analysis (AAA). Using the aerodynamic derivatives, it provides the base line of normal/failure for the control surface by using the on-line parameter estimation of Fourier transform regression. In flight, this approach maybe helpful to detect and isolate the fault of primary control surface. It is explained how to perform the flight condition assumed as the right elevator fixed in the flight test. Also, it is mentioned how to switch between the normal flight condition and the assumed fault flight condition.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.571-586
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• 2014

Moderate Resolution Imaging Spectroradiometer (MODIS) provides air temperature (Tair) and dew point temperature (Tdew) profiles at a spatial resolution of 5 km. New Collection 6 (C006) MODIS07_L2 atmospheric profile product has been produced since 2012. The Collection 6 algorithm has several modifications from the previous Collection 5 (C005) algorithm. This study evaluated reliabilities of two alternative datasets of surface-level Tair and Tdew derived from C005 and C006 Aqua MODIS07_L2 (MYD07_L2) products using ground measured temperatures from 77 National Weather Stations (NWS). Saturated and actual vapor pressures were calculated using MYD07_L2 Tair and Tdew. The C006 Tair showed lower mean error (ME, -0.76 K) and root mean square error (RMSE, 3.34 K) than the C005 Tair (ME = -1.89 K, RMSE = 4.06 K). In contrasts, ME and RMSE of C006 Tdew were higher than those (ME = -0.39 K, RMSE = 5.65 K) of C005 product. Application of ambient lapse rate for Tair showed appreciable improvements of estimation accuracy for both of C005 and C006, though this modification slightly increased errors in C006 Tdew. The C006 products provided better estimation of vapor pressure datasets than the C005-derived vapor pressure. Our results indicate that, except for Tdew, C006 MYD07_L2 product showed better reliability for the region of South Korea than the C005 products.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.58-66
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• 2014

Water pollution problems of urban rivers due to the urbanization and industrialization have been the subject of public attention. In particular, considering the fact that the characteristics of water cycle of each basin change dramatically through the development of new towns, a large number of concerns about future water quality have been raised. However, reasonable measures to predict future water quality quantitatively have not been presented by this moment. In this study, by the linkage of annual unit load generation based on long-term monitoring results of the ministry of environment (MOE) to a semi-distributed rainfall runoff model, SWMM (Storm Water Management Model), we proposed a new methodology to estimate future water quality macroscopically and testified it to verify its applicability for the estimation of future water quality of a small watershed at G new town. As a result of the estimation using Y-EMC (Yearly based Event Mean Concentration), future water quality were simulated as BOD 18.7, T-N 16.1 and T-P 0.85 mg/L respectively which could not achieve the grade III of domestic river life guidance and these criteria could be satisfied by the reduction of domestic wastewater discharge load by over 80%. The results of this study are shown to be utilized for one of basic tools to estimate and manage water quality of urban rivers in the course of new town developments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.8
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• pp.911-916
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• 2014

The leisure boat industry has the potential to become a high-value-added industry in the future. Recently, a study on Korean high-speed leisure boats for fishing was conducted. This study suggests a product configuration model-based shipbuilding cost estimation method for determining the type of leisure boat suitable for mass production, as part of a research for productivity improvement. The suggested estimation method based on the analysis of the leisure boat process and generic YWBS can calculate quantitative and concrete data. By using this method, the cost of building the catamaran-type design ship can be reduced by 17 times, compared to that of the monohull-type mother ship. This implies that the final design of the Korean high-speed leisure boat for fishing will have a competitive price at the actual production stage.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.285-291
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• 2017

Many methods have been studied to estimate the time delay between incoming signals to two receivers. In the case of the method based on the channel estimation technique, the relative delay between the input signals of the two receivers is estimated as an impulse response of the channel between the two signals. In this case, the characteristic of the channel has sparsity. Most of the existing methods do not take advantage of the channel sparseness. In this paper, we propose a time delay estimation method using BPD (Basis Pursuit Denoising) optimization technique, which is one of the sparse signal optimization methods, in order to utilize the channel sparseness. Compared with the existing GCC (Generalized Cross Correlation) method, adaptive eigen decomposition method and RZA-LMS (Reweighted Zero-Attracting Least Mean Square), the proposed method shows that it can mitigate the threshold phenomenon even under a white Gaussian source, a colored signal source and oceanic mammal sound source.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1522-1533
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• 2001

In this paper, we handle the estimation method of the received $E_{b}l1_{o}$ for forward closed-loop power control in cdma2000 systems. The estimation of MS-received $E_{b}l1_{o}$ utilizes the symbols related to the forward power control subchannel transmission. The estimation of the received bit energy and noise variance is analyzed for the frequency-selective Rayleigh fading channel. In order to improve SIR (signal-to-interference), the estimation of the received bit energy is made by the coherent combining of the rake-fingers and received I/Q symbols. And, in this paper, we evaluate the performance of forward closed-loop power control according to the mobile speed and the power adjustment step size in terms of the bit error rate (BER) and power control error. Simulation results present the optimal power adjustment step sizes according to the mobile speeds.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.434-445
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• 2004

Motion Estimation is an essential module in video encoders based on international standards such as H.263 and MPEG. Many fast motion estimation algorithms have been proposed in order to reduce the computational complexity of a well-known full search algorithms(FS). However, these fast algorithms can not work efficiently in DSP processors recently developed for video processing. To solve for this. we propose an efficient motion estimation scheme optimized in the DSP processor like Philips TM1300. A motion vector predictor is pre-estimated and a small search range is chosen in the proposed scheme using strong motion vector correlation between a current macro block (MB) and its neighboring MB's to reduce computation time. An MPEG-4 SP@L3(Simple Profile at Level 3) encoding system is implemented in Philips TM1300 to verify the effectiveness of the proposed method. In that processor, we can achieve better performance using our method than other conventional ones while keeping visual quality as good as that of the FS.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.17-23
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• 2005

In order to examine effects of sampling frequency during rainfall-runoff process from paddy field on the estimation of pollution load, EMCs of several water sampling frequencies were examined. Water quality samples were conducted by every two hours interval for each event. It was found that difference of load estimation between five times sampling and two hours consecutive sampling during rainfall-runoff showed $15.2{\sim}-15.2%$ for T-N, $20.0{\sim}-26.2%$ for T-P, $28.6{\sim}-35.7%$ for the SS, respectively. In the same way, the effects of number of sampling data on estimation of pollution load using runoff-mass load(L-Q) method were investigated. L-Q equation made of five times sampling data provided 10% differences in estimation of mass loads of T-N, T-P, and SS when compared to those by L-Q equation using entire two hours consecutive sampling data during runoff process.

• Journal of Korea Water Resources Association
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• v.53 no.8
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• pp.597-604
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• 2020

Muskingum, a hydrologic channel flood routing, is a method of predicting outflow by using the relationship between inflow, outflow, and storage. As many studies for Muskingum model were suggested, parameters were gradually increased and the calculation process was complicated by many parameters. To solve this problem, an optimization algorithm was applied to the parameter estimation of Muskingum model. This study applied the Advanced Nonlinear Muskingum Model considering continuous flow (ANLMM-L) to Wilson flood data and Sutculer flood data and compared results of the Linear Nonsingum Model incorporating Lateral flow (LMM-L), and Kinematic Wave Model (KWM). The Sum of Squares (SSQ) was used as an index for comparing simulated and observed results. Exponential Bandwidth Harmony Search with Centralized Global Search (EBHS-CGS) was applied to the parameter estimation of ANLMM-L. In Wilson flood data, ANLMM-L showed more accurate results than LMM-L. In the Sutculer flood data, ANLMM-L showed better results than KWM, but SSQ was larger than in the case of Wilson flood data because the flow rate of Sutculer flood data is large. EBHS-CGS could be appplied to be appplicable to various water resources engineering problems as well as Muskingum flood routing in this study.

• Analytical Science and Technology
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• v.7 no.3
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• pp.285-291
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• 1994

A microbial BOD sensor for the continuous estimation of BOD was been developed by immobilizing Trichosporon cutaneum, which was immobilized between a dialysis and a gas-permeable membrane, on an oxygen electrode. The optimum pH and temperature for BOD measurement using this sensor were pH 7.0 and $32{\sim}33^{\circ}C$, respectively. The best result was obtained at 2~3ml/min flow rate in 0.1M phosphate buffer solution. A linear relationship was observed between ${\Delta}DO$ and the concentration of standard GGA solution below 60mg/l(90ppm $BOD_5$). The reproducibility was found to be within 3% for the standard solution containing glucose 30mg/l and glutamic acid 30mg/l. The output DO value of this sensor was almost constant for 30 dalys. The response time and the recovery time were about 5 and 10 min, respectively. This sensor was employed for the BOD measurement of waste pollutants and was compared with $BOD_5$ method.