• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.835-843
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• 2010

Energy spreading transform (EST) based equalization is a very effective technique to remove inter symbol interference (ISI) in frequency selective channel. EST based system uses cyclic prefix (CP) similar to orthogonal frequency division multiplexing (OFDM) system. Since CP is a redundancy, it degrades the data transmission rate. RISIC is an algorithm that removes an inter block interference (IBI) caused by insufficient CP length and reconstructs CP. In this paper, we propose a system that combines the existing EST system with quadrature phase shift keying (QPSK) modulation and RISIC algorithm to enhance the efficiency of the transmission. Also we extend the proposed system to 16 quadrature amplitude modulation (QAM) modulation. The proposed system is shown to performance close to matched filter bound (MFB) even with insufficient CP.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.459-473
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• 2008

This study investigated typhoon characteristics that provoke precipitation which is much attacking periodically in our country, and calculated probability precipitation of extreme rainfalls using Empirical Simulation Technique. The typhoon influenced in Korea was happened 3.18 times per, and year exposed to affect Korea during 107 hours. The depth of precipitation with the typhoon was different according to observation points. The extreme precipitation of typhoon events has analyzed by change and trend analyses. In the results, mean and standard deviation of extreme rainfall has been increasing than the past events in some areas. Also, About 143 typhoons influenced Korea was applied in EST techniques using center position, central pressure, time precipitation data using rainfall observatory in Korea. Therefore, we applied EST techniques and calculated probability precipitation. In the results, Jeonla-do, Gyeongsang-do and Gangwon-do will have heavy rain with typhoon events in high probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.682-693
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• 2011

Energy spreading transform (EST) based modulation is an effective technique to combat frequency-selective fading in broadband wireless communication. It performs close to the inter-symbol interference (ISI)-free matched filter bound (MFB) only at the complexity of a linear detector. Originally, EST-based modulation has been proposed for QPSK. However, to fully utilize the capacity of multipath fading channels, higher-order modulations are also necessary. In this paper, we review the EST based modulation that has originally been proposed for QPSK and discuss its extension to 8 PSK and 16 QAM. The performance of the extended system is verified through simulation in Proakis B and 8-tap fading channel. The EST based modulation for 8 PSK shows the performance which is very close to MFB and the EST based modulation for 16 QAM shows the performance gap between its receiver and MFB.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.193-205
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• 2009

Typhoons occurred in the tropical Pacific region, these might be affected the Korea moving toward north. The strong winds and the heavy rains by the typhoons caused a natural disaster in Korea. In the research, the heavy rainfall events based on typhoons were evaluated quantitative through various statistical techniques. First, probability precipitation and typhoon probability precipitation were compared using frequency analysis. Second, EST probability precipitation was calculated by Empirical Simulation Techniques (EST). Third, NL probability precipitation was estimated by coupled Nonparametric monte carlo simulation and Locally weighted polynomial regression. At the analysis results, the typhoons can be effected Gangneung and Mokpo stations more than other stations. Conversely, the typhoons can be effected Seoul and Inchen stations less than other stations. Also, EST and NL probability precipitation were estimated by the long-term simulation using observed data. Consequently, major hydrologic structures and regions where received the big typhoons impact should be review necessary. Also, EST and NL techniques can be used for climate change by the global warming. Because, these techniques used the relationship between the heavy rainfall events and the typhoons characteristics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.3
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• pp.210-216
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• 2012

EST has been applied to the East Coast to estimate extreme sea levels. Surge heights induced by 51 typhoons which have occurred last 60 years were calculated by ADCIRC model. The training set which is consist of surge heights by both typhoon and monsoon was constructed. The maximum surge height of the year excluding the one by typhoon is considered to be the surge height by monsoon. High/low tide conditions and spring/neap tide conditions were considered for constructing input vectors of typhoon and monsoon, respectively. The annual tide is also considered in response vectors for each case. The result is in accord with Jeong et al. (2008), which implies validity of the present study.

• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.93-99
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• 1996

This study was designed to investigate the effect of estrogen(Est) on the progestcrone(Prog) target cells by autoradiography. The spayed 16 mice(ICR, approximately 18~25g) were randomly alloted into 3 groups. $^3H$-Prog-treated group were injected with $40{\mu}Ci$ of $^3H$-Prog/mouse/day for 1 day, Est + $^3H$-Prog-treated group with $20{\mu}Ci$ of $17{\beta}$-Est/mouse/day for 3 days and then with $40{\mu}Ci$ of $^3H$-Prog/mouse at 4th day, and Est+$^3H$-thymidine(TdR)-treated group with $20{\mu}g$ of $17{\beta}$-Est/mouse/day for 3 days and then $80{\mu}Ci$ of $^3H$-TdR/mouse at 4th days. 1. Mice uteri of both Est+$^3H$-Prog-treated group and Est+$^3H$-TdR-treated group were hypemophied in gross finding and the endometrium and myometrium were thickened in microscopic findings. These findings were confirmed that Est enlarged the uteri of mice. 2. Cryo-preparations of mice organs were processed for autoradiography using Kodak NTB-2 emulsion following Kodak D-19 developer and hematoxylin counterstain. In each group, the number values of silver grain distribution appeared to be higher in the $^3H$-Prog-treated group than in the Est+$^3H$-Prog-treated group. It was considered that Est and Prog inhibit each other in action. 3. In both $^3H$-Prog-treated group and Est+$^3H$-Prog-treated group, the uteri have highest distribution rates of silver grains than in other organs, and the cerebral neurons, hepatocytes, bronchiolar epithelial cells and splenic reticular cells also contained some silver grains. 4. The orders of the cell types with more number of silver grains in the uteri were stromal cells, glandular epithelial cells, luminal surface cells and muscular cells and also were as above orders in distribution of proliferating cell type by $^3H$-TdR.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.825-839
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• 2005

Application of the EST approach for the simulation of the risk-based typhoon hazard potential is described in this paper. For six selected cities In the Korean peninsula, EST simulations for one hundred years were performed one hundred times using historical typhoon data as a training data set. The analytical results of EST simulations were then post-processed to estimate the means, standard deviations, and ranges of variation for the maximum wind velocities and the daily rainfalls. From the comparison of the averages of the wind velocities for the 100 year recurrence interval typhoons, the wind hazard potential of them was revealed to be highest for Mokpo among the six cities, followed by Busan, Cheju, Inchun, Taegu, and Seoul in descending order For the flood hazard potential associated with a typhoon, Busan was ranked to be the highest hazard potential area, followed by Mokpo, Cheju, Seoul, Inckun, and Taegu. In terms of the overall typhoon hazard potential, cities in the southern coastal regions were identified as being exposed to the most severe typhoon hazard.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.254-265
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• 2009

The estimation of the extreme sea level is necessary in the design of offshore or coastal structures. In this paper, the storm surge data calculated numerically at 52 harbors around the Korean Peninsula are analyzed by using annual maximum series(AMS), peaks over threshold(POT) and empirical simulation technique(EST). The maximum likelihood method was used to estimate the parameters in both AMS and POT models. The Generalized Pareto distribution was used and Chi-square and Kolmogorov-Smirnov goodness-of-fit tests were performed with the acceptable significance level 5%. The extreme sea levels were also evaluated by EST including tide effect, showing similar results as given by Jeong et al.(2008).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.381-389
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• 2012

An EST-based method which is applicable for estimating extreme sea levels from short sea-level records in a tide dominated coastal zone was developed. Via the method, annual maximum tidal level is chosen from the simulated 1-yr tidal data which are constituted by the independent daily high water levels, short term and long term surge heights and typhoon-induced surge heights. The high water levels are generated considering not only spring/neap tides and annual tide but also 18.6-year lunar nodal cycle. Typhoon-induced surges are selected from the training set which is constructed by observed or simulated surge heights. This yearly simulation is repeated many hundred years to yield the extreme tidal levels, and the whole process is carried out many hundred times repeatedly to get robust statistics of the levels. In addition, validation of the method is also shown by comparing the result with other researches with the tidal data of Mokpo Harbor.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.148-153
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• 2010

The aim of this study was to investigate the virulence factor profiles of Escherichia coli strains isolated from pork and chicken meats purchased from retail markets in Korea. From 943 pork and 142 chicken meats, 217 isolates of E. coli were cultured. The presence of 11 virulence factors (elt, estI, estII, astA, stx, cdt, cnf, agg, inve, eae, afa) were detected by polymerase chain reaction. Forty one (18.9%) of 217 E. coli isolates carried at least one virulence factor. Among 175 E. coli isolates from pork, the detection rate of astA, elt, eae, estII, estI, afa, and cnf were 6.9%, 4.6%, 4.6%, 4.0%, 2.3%, 1.1%, and 0.6%, respectively. However, stx, agg, and cdt were not detected in our isolates. Therefore, we conclude that astA is the most prevalent virulence factor in E. coli isolates contaminated in pork and chicken meats in Korea.