• Journal of Biosystems Engineering
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• v.17 no.2
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• pp.132-142
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• 1992

The main objective of this paper is to evaluate and modify the existing algorithms for the automatic threshold selection. Four existing algorithms were evaluated quantitatively using test images of coffee droplets and an apple. The images had the different area ratio of the object to the image size, different average gray values between the object and the background, and different S/N ratio of the Gaussian noise. The result showed that Histogram Clustering Method and Maximum Entropy Method were better than Moment Preserving Method and Simple Image Statistic Method in automatic thresholding.

• The Korean Journal of Applied Statistics
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• v.18 no.2
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• pp.435-443
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• 2005

Coefficients of determination in logistic regression analysis are defined as various statistics, and their values are relatively smaller than those for linear regression model. These coefficients of determination are not generally used to evaluate and diagnose logistic regression model. Liao and McGee (2003) proposed two adjusted coefficients of determination which are robust at the addition of inappropriate predictors and the variation of sample size. In this work, these adjusted coefficients of determination are applied to variable selection method for logistic regression model and compared with results of other methods such as the forward selection, backward elimination, stepwise selection, and AIC statistic.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.792-796
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• 2005

The methods of times series analysis have been recognized as important tools for assisting in solving problems related to the management of water resources. Especially, After more than 40 years the so-called Hurst effect remains an open problem in stochastic hydrology. Until now, its existence has been explained fly R/S analysis that roots in early work of the British hydrologist H.E. Hurst(1951). Today, the Hurst analysis is mostly used for the hydrological studies for memory and characteristics of time series and many methodologies have been developed for the analysis. So, there are many different techniques for the estimation of the Hurst exponent(H). However, the techniques can produce different characteristics for the persistence of a time series each other. We found that DFA is the most appropriate technique for the Hurst exponent estimation for both the shot term memory and long term memory. We analyze the SOI(Southern Oscillations Index) and 6 tree-ring series for USA sites by means of DFA and the BDS statistic is used for nonlinearity test of the series. From the results, we found that SOI series is nonlinear time series which has a long term memory of H=0.92. Contrary to earlier work of Rao(1999), all the tree- ring series are not random from our analysis. A certain tree ring series show a long term memory of H=0.97 and nonlinear property. Therefore, we can say that the SOI and tree-ring series may show long memory and nonlinearity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.95-106
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• 2018

To evaluate appropriate reference genes for the normalization of quantitative reverse transcription PCR (RT-qPCR) data with embryonic and larval samples from Russian sturgeon Acipenser gueldenstaedtii, the expression stability of eight candidate housekeeping genes, including beta-actin (ACTB), elongation factor-1A (EF1A), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone 2A (H2A), ribosomal protein L5 (RPL5), ribosomal protein L7 (RPL7), succinate dehydrogenase (SDHA), and ubiquitin-conjugating enzyme E2 (UBE2A), were tested using embryonic samples from 12 developmental stages and larval samples from 11 ontogenic stages. Based on the stability rankings from three statistic software packages, geNorm, NormFinder, and BestKeeper, the expression stability of the embryonic subset was ranked as UBE2A>H2A>SDHA>GAPDH>RPL5>EF1A>ACTB>RPL7. On the other hand, the ranking in the larval subset was determined as UBE2A>GAPDH>SDHA>RPL5>RPL7>H2A>EF1A>AC TB. When the two subsets were combined, the overall ranking was UBE2A>SDHA>H2A>RPL5>GAPDH>EF1A>ACTB>RPL7. Taken together, our data suggest that UBE2A and SDHA are recommended as suitable references for developmental and ontogenic samples of this sturgeon species, whereas traditional housekeepers such as ACTB and GAPDH may not be suitable candidates.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.7 s.361
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• pp.45-53
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• 2007

In this paper, we propose an efficient hardware architecture for H.264/AVC CAVLC (Context-based Adaptive Variable Length Coding) encoding. Previous CAVLC architectures search all of the coefficients to find statistic characteristics in a block. However, it is unnecessary information that zero coefficients following the last position of a non-zero coefficient when CAVLC encodes residual coefficients. In order to reduce this unnecessary operation, we propose two techniques, which detect the first and last position of non-zero coefficients and arrange non-zero coefficients sequentially. By adopting these two techniques, the required processing time was reduced about 23% compared with previous architecture. It was designed in a hardware description language and total logic gate count is 16.3k using 0.18um standard cell library Simulation results show that our design is capable of real-time processing for $1920{\times}1088\;30fps$ videos at 81MHz.

• Korean journal of communication and information
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• v.41
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• pp.41-74
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• 2008

Based on the theory of news media's agenda-setting function, this study analyzed Korean public's most important problems (MIP) and the degree of public consensus on the importance of those MIP's. The analysis was done in terms of both time and social strata. According to the findings, economy, social welfare, and political issues were in the for tier of the MIP list. The analysis of issue diversity (H-statistic) also demonstrated a relatively high degree of agenda consensus among Korean public despite some fluctuation in the consensus level, which appears to be higher than that among the American public. A decrease in the degree of agenda consensus with the passage of time appealed to be a general phenomenon across diverse social strata. However, the degrees of consensus-building were different in light of education, socioeconomic status, and the size of residential area. Those who are more educated, have more economic power, and live in a larger city had more chances to experience agenda consensus. These results seem to be basically attributable to the presumed positive relationship between these demographic variables and media exposure. The different degrees of public consensus according to the different levels of those demographic variables suggest that a closer investigation into the various influences on the importance of public issues among the respondents should be done in future studies.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1102-1110
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• 2010

Tidal mudflat is a reservoir for diverse microbial resources. Microbial diversity in tidal mudflat sediment can be easily influenced by various human activities. It is necessary to take representative samples to monitor microbial diversity in tidal mudflat sediments. In this study, we analyzed the microbial diversity and chemical characteristics of vegetation and non-vegetation tidal mudflat regions in the Kangwha tidal mudflat using geo-statistics and data-mining. According to the geo-statistical analysis, most correlation range values for the vegetation region were smaller than those for the non-vegetation region, which suggested that the shorter number and interval of sampling are required for the vegetation tidal mudflat environment due to its higher degree of chemical and biological complexity and heterogeneity. The data-mining analysis suggested that the organic content and nitrate were the major environmental factors influencing microbial diversity in the vegetation region while pH and sulfate were the major influencing factors in the non-vegetation region. Using the geo-statistical and data-mining integration approach, we proposed a guideline for determining the sampling interval and number to monitor microbial diversity in tidal mudflat.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1699-1706
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• 2015

The purpose of this study is to induce a indicator related to the response, handling and management which are appeared on each step of business enforcement in housing reconstruction projects. Then, it aims to appropriately and reasonably resolve the conflicts of reconstruction business with relevant subjects. These projects physician satisfaction and continual business was going to have the impact that any analysis of the structure in an evaluation. In addition, this study analyzes the impact structure on the business satisfaction and a intention for continuous business through this evaluation. This study sets a operational hypothesis in order to verify the relationship between the variables. then, it creates the structural model by using the Smart PLS 3.0. After analyzing the impact structure by using total 252 samples, this study adopts the final hypothesis which shows (+) path coefficient as set in the hypothesis and test statistic above 1.65. In result, six out of the nine hyphothesis are adopted. then, The 'Response to conflict' which affects the 'Management to conflict(H1)' has a path coefficient of 0.618. In addition, the 'Handling to conflict' which affects the 'Management to conflict(H2)' has a path coefficient of 0.150. The 'Handling to conflict' which affects the satisfaction of 'business' has a path coefficient of 0.101. and the 'management to conflict' which affects the satisfaction of 'business(H7)' has a path coefficient of 0.644. In addition, the 'Intention for continuous business(H8)' shows a path coefficient of 0.258. Finally, The satisfaction of 'business' which affects the 'intention for continuous business(H9)' has a path coefficient of 0.391.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.500-509
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• 2015

The purpose of this study is to induce a indicator related to the response, handling and management which are appeared on each step of business enforcement in Reconstruction projects. Then, it aims to appropriately and reasonably resolve the conflicts of reconstruction business with relevant subjects. These projects physician satisfaction and continual business was going to have the impact that any analysis of the structure in an evaluation. In addition, this study analyzes the impact structure on the business satisfaction and a intention for continuous business through this evaluation. This study sets a operational hypothesis in order to verify the relationship between the variables. then, it creates the structural model by using the Smart PLS 3.0. After analyzing the impact structure, this study adopts the final Five hypothesis which shows (+) path coefficient as set in the hypothesis and test statistic above 1.65. then, The 'Approval for union establishment(H1)' has a path coefficient of 0.127. In addition, the 'Approval for business enforcement(H2)' has a path coefficient of 0.343. The 'Management and disposition plan(H4)' has a path coefficient of 0.145. and the 'External Factors(H6)' has a path coefficient of 0.124. Finally, The 'satisfaction of business' which affects the 'intention for continuous business(H7)' has a path coefficient of 0.727.

• Journal of Preventive Medicine and Public Health
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• v.38 no.3
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• pp.276-282
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• 2005

Objectives : To evaluate the predictive validity of three scoring systems; the acute physiology and chronic health evaluation(APACHE) III, simplified acute physiology score(SAPS) II, and mortality probability model(MPM) II systems in critically ill patients. Methods : A concurrent and retrospective study conducted by collecting data on consecutive patients admitted to the intensive care unit(ICU) including surgical, medical and coronary care unit between January 1, 2004, and March 31, 2004. Data were collected on 348 patients consecutively admitted to the ICU(aged 16 years or older, no transfer, ICU stay at least 8 hours). Three models were analyzed using logistic regression. Discrimination was assessed using receiver operating characteristic(ROC) curves, sensitivity, specificity, and correct classification rate. Calibration was assessed using the Lemeshow-Hosmer goodness of fit H-statistic. Results : For the APACHE III, SAPS II and MPM II systems, the area under the receiver operating characterist ic(ROC) curves were 0.981, 0.978, and 0.941 respectively. With a predicted risk of 0.5, the sensitivities for the APACHE III, SAPS II, and MPM II systems were 81.1, 79.2 and 71.7%, the specificities 98.3, 98.6, and 98.3%, and the correct classification rates 95.7, 95.7, and 94.3%, respectively. The SAPS II and APACHE III systems showed good calibrations(chi-squared H=2.5838 p=0.9577 for SAPS II, and chi-squared H=4.3761 p=0.8217 for APACHE III). Conclusions : The APACHE III and SAPS II systems have excellent powers of mortality prediction, and calibration, and can be useful tools for the quality assessment of intensive care units(ICUs).