• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.937-945
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• 2013

The accuracy of flood inundation maps is determined by the uncertainty propagated from all variables involved in the overall process including input data, model parameters and modeling approaches. This study investigated the uncertainty arising from key variables (flow condition and Manning's n) among model variables in flood inundation mapping for the Missouri River near Boonville, Missouri, USA. Methodology of this study involves the generalized likelihood uncertainty estimation (GLUE) to quantify the uncertainty bounds of flood inundation area. Uncertainty bounds in the GLUE procedure are evaluated by selecting two likelihood functions, which is two statistic (inverse of sum of squared error (1/SAE) and inverse of sum of absolute error (1/SSE)) based on an observed water surface elevation and simulated water surface elevations. The results from GLUE show that likelihood measure based on 1/SSE is more sensitive on observation than likelihood measure based on 1/SAE, and that the uncertainty propagated from two variables produces an uncertainty bound of about 2% in the inundation area compared to observed inundation. Based on the results obtained form this study, it is expected that this study will be useful to identify the characteristic of flood.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.939-947
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• 2010

The LDPC(Low-Density Parity-Check) code, which is one of the channel encoding methods in IEEE 802.11n wireless LAN standard, has superior error-correcting capabilities. Since the hardware complexity of LDPC decoder is high, it is very important to take into account the trade-offs between hardware complexity and decoding performance. In this paper, the effects of LLR(Log-Likelihood Ratio) approximation on the performance of MSA(Min-Sum Algorithm)-based LDPC decoder are analyzed, and some optimal design conditions are derived. The parity check matrix with block length of 1,944 bits and code rate of 1/2 in IEEE 802.11n WLAN standard is used. In the case of $BER=10^{-3}$, the $E_b/N_o$ difference between LLR bit-widths (6,4) and (7,5) is 0.62 dB, and $E_b/N_o$ difference for iteration cycles 6 and 7 is 0.3 dB. The simulation results show that optimal BER performance can be achieved by LLR bit-width of (7,5) and iteration cycle of 7.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.44-53
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• 2005

In this paper, a improved moving object detection algorithm for stable performance of surveillance system in case of iterative moving in limited area and rapidly illuminance change in background scene is proposed. The proposed algorithm is that background scenes are sampled for initializing background image then the sampled fames are divided by block and sum of graylevel value for each block pixel was calculated, respectively. The initialization of background image is that background frame is respectively reconstructed with selecting only the maximum graylevel value and the minimum graylevel value of blocks located at same position between adjacent frames, then reference images of background are set by the reconstructed background images. Moving object detecting is that the current image frame is divided by block then sum of graylevel value for each block pixel is calculated. If the calculated value is out of graylevel range of the initialized two reference images, it is decided with moving objects block, otherwise it is decided background. The evaluated results is that the error rate of the proposed method is less than the error rate of the existing methods from $0.01{\%}$ to $20.33{\%}$ and the detection rate of the proposed method is better than the existing methods from $0.17{\%}\;to\;22.83{\%}$.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.636-642
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• 2019

In this paper, we analyzed BER (Bit Error Rate) communication performance according to the detection order of MMSE (Minimum Mean Square Error) based soft decision interference cancellation. As the detection order method, antenna index order method, absolute value magnitude order method of channel elements, absolute value sum order method of channel elements, and SNR (Signal Noise Ratio) order method are proposed. BER performance for the scheme was measured and analyzed. As a simulation environment, 16-QAM (Quadrature Amplitude Modulation) modulation is used in an uncoded environment of an M×M multiple-input multiple-output system, and an independent Rayleigh attenuation channel is considered. The simulation results show that the performance gain is about 1.5dB when the SNR-based detection order method is M=4, and the performance gain is about 3.5dB when M=8 and about 3.5dB when M=16. The more BER performance was confirmed, the more the detection order method of the received signal prevented the interference and error spreading occurring in the detection process.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.318-327
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• 2017

It is essential for the near-field receiving measurement to make beam pattern and check the performance of a active phased array antenna system. Also, we could obtain compensation value for mono-pulse function through the near-field receive test, however, if the radar has many frequency channel, the test would take long time and hard effort. So it is needed that frequency channels are selected for measurement and calculates the values for other frequency channels to improve efficiency in development and manufacture. In this case, the phase variations in sum and del channels would be checked. The phase measurement includes un-linear characteristic because of wrapping effect. Generally, radars have similar path length in sum and del channel, but if a radar has a electrical length gap between sum and del channel, errors could occur by phase's wrapping effect. In this paper, the interpolation method's error caused by electrical length gap is checked and the effective method for frequency channel selection to avoid wrapping effect is introduced.

• The Journal of Korean Medicine
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• v.19 no.1
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• pp.299-326
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• 1998

1. Comparison of demand and supply A. Assumption of estimation of demand and supply we will briefly assumptions used for presumption once more before comparing the result of estimation of demand and supply examined previously 1) supply - The average applying rate for state. examination of graduate: ${\alpha}$=1.03109 - The ratio of successful applicants of state examinations: ${\beta}$=0.97091 - Mortality classified by age : presumed data of the Bureau of statistics - Emigrating rate: 0 % - Time of retire: unconsidered - An army doctor number: unconsidered and regard number of employed oriental medicine doctor. - Standard of 1995 : The number of survival oriental medicine doctor is 8195. the number of employed oriental medicine doctor is 7419. 2) demand - derivated demand method Daily the average amount of medical treatment: according to medical insurance federation data. there is 16 or 6 non allowance patient, we consider amount of medical treatment as 22 persons in practical because 21.94 persons (founded practical examination) are converted to allowance in comming demand. Daily the proper amount of medical treatment: 7 hours form -35 persons 5 hours 30 minutes form -28 persons. Yearly medical treatment days: 229 days. 255 days. 269 days . Increasing rate of visiting hospital days: -1996 year. 1997 year. 1998 year- . Rate of applying insurance: yearly average 71.51% (among the investigated patient) B. Comparison of total sum result 1) supply (provision) Table Ⅳ-1 below shows the estimation of the oriental medicine doctor in the future.