• The Korean Journal of Applied Statistics
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• v.34 no.3
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• pp.439-447
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• 2021

Due to the frequent emergence of global abnormal climates, related studies on meteorological change is being actively proceed. However, the research on trend analysis using weather data accumulated over a long period of time was insufficient. In this study, the trend of temperature time series data accumulated from automated surface observing system (ASOS) for 40 years was analyzed by using a non-parametric analysis method. As a result of the Mann-Kendall test on the annual average temperature and seasonal average temperature time series data in South Korea, it has shown that an upward trend exists. In addition, the result of calculating the Sen's slope, which can determine the degree of tendency before and after the searched change point by applying the Pettitt test, recent data after the fluctuation point confirmed that the tendency of temperature rise was even greater.

• Journal of Korea Water Resources Association
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• v.46 no.3
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• pp.219-227
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• 2013

Time series data including change, jump, trend and periodicity generally have nonstationarity. Especially, various methods have been proposed to identify the trend about hydrological time series data. However, among various methods, evaluation about capability of each trend test has not been done a lot. Even for the same data, each method may show the different result. In this study, the simulation was performed for identification about the changes in trend analysis according to the statistical characteristics and the capability in the trend analysis. For this purpose, power test for the trend analysis is conducted using Men-Kendall test, Hotelling-Pabst test, t test and Sen test according to the slope, sample size, standard deviation and significance level. As a result, t test has higher statistical power than the others, while Mann-Kendall, Hotelling-Pabst, and Sen tests were similar results.

• Korean Journal of Radiology
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• v.22 no.6
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• pp.959-969
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• 2021

Objective: This study aimed to evaluate the role of preoperative two-dimensional (2D) shear wave elastography (SWE) in assessing the stages of liver fibrosis in patients with suspected biliary atresia (BA) and compared its diagnostic performance with those of serum fibrosis biomarkers. Materials and Methods: This study was approved by the ethical committee, and written informed parental consent was obtained. Two hundred and sixteen patients were prospectively enrolled between January 2012 and October 2018. The 2D SWE measurements of 69 patients have been previously reported. 2D SWE measurements, serum fibrosis biomarkers, including fibrotic markers and biochemical test results, and liver histology parameters were obtained. 2D SWE values, serum biomarkers including, aspartate aminotransferase to platelet ratio index (APRi), and other serum fibrotic markers were correlated with the stages of liver fibrosis by METAVIR. Receiver operating characteristic (ROC) curves and area under the ROC (AUROC) curve analyses were used. Results: The correlation coefficient of 2D SWE value in correlation with the stages of liver fibrosis was 0.789 (p < 0.001). The cut-off values of 2D SWE were calculated as 9.1 kPa for F1, 11.6 kPa for F2, 13.0 kPa for F3, and 15.7 kPa for F4. The AUROCs of 2D SWE in the determination of the stages of liver fibrosis ranged from 0.869 to 0.941. The sensitivity and negative predictive value of 2D SWE in the diagnosis of ≥ F3 was 93.4% and 96.0%, respectively. The diagnostic performance of 2D SWE was superior to that of APRi and other serum fibrotic markers in predicting severe fibrosis and cirrhosis (all p < 0.005) and other serum biomarkers. Multivariate analysis showed that the 2D SWE value was the only statistically significant parameter for predicting liver fibrosis. Conclusion: 2D SWE is a more effective non-invasive tool for predicting the stage of liver fibrosis in patients with suspected BA, compared with serum fibrosis biomarkers.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5775-5781
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• 2013

Background: The gastroenteropancreatic neuroendocrine neoplasm (GEP-NEN) is the most common type of neuroendocrine neoplasm. We summarized data in our centre to investigate the clinicopathological features, diagnostic methods, therapeutic approaches and prognosis for this neoplasm to increase knowledge of this disease in Asian populations. Method: A total of 122 patients treated at Sun Yet-san Memorial Hospital of Sun Yat-sen University between January 2000 and December 2011 were analyzed retrospectively. Results: Pancreas was the most common site of involvement (65/122, 53.3%); this disease has no special symptoms; positive rates of chromogranin A (CgA) and synaptophysin (Syn) were 81.1% and 87.7%, respectively. The positive rate of Syn had statistical difference among the three grades, but not CgA. Some 68 patients had G1 tumors, 32 G2 tumors and 22 G3 tumors, and Chi-square test showed that higher grading was correlated with worse prognosis (${\chi}^2=32.825$, P=0.0001). A total of 32 patients presented with distant metastasis, and 8 cases emerged during following up. Cox proportional hazards regression modeling showed that the tumor grade (P=0.01), lymphatic metastasis (P=0.025) and distant metastasis (P=0.031) were predictors of unfavorable prognosis. The overall 5-year survival rate was 39.6%, the 5-year survival rate of G1 was 55.7%, and the G2 and G3 were 34.2% and 0%, respectively. Conclusions: The incidence of gastroenteropancreatic neuroendocrine tumors has risen over the last 12 years. All grades of these diseases metastasize readily, and further research regarding the treatment of patients after radical surgery is needed to prolong disease-free survival.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4759-4763
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• 2013

Background: Prognostic factors of postoperative early and late recurrence in patients with hepatocellular carcinoma (HCC) undergoing curative resection remain to be clarified. The aim of this study was to identify risk factors for postoperative early (${\leq}$ 2 year) and late (> 2 year) intrahepatic recurrences in patients with single HCCs without macrovascular invasion. Methods: A total of 280 patients from December 2004 to December 2007 were retrospectively included in this study. Intrahepatic recurrence was classified into early (${\leq}$ 2 year) and late (> 2 year) and the Chi-Square test or Fisher's exact test and multivariate logistic regression analysis were performed to determine significant risk factors. Results: During the follow-up, 124 patients had intrahepatic recurrence, early and late in 82 and 42 patients, respectively. Multivariate logistic regression analysis showed that microvascular invasion (p=0.006, HR: 2.397, 95% CI: 1.290-4.451) was the only independent risk factor for early recurrence, while being female (p = 0.031, HR: 0.326, 95% CI: 0.118-0.901), and having a high degree of cirrhosis (P=0.001, HR: 2.483, 95% CI: 1.417-4.349) were independent risk factors for late recurrence. Conclusions: Early and late recurrence of HCC is linked to different risk factors in patients with single HCC without macrovascular invasion. This results suggested different emphases of strategies for prevent of recurrence after curative resection, more active intervention including adjuvant therapy, anti-cirrhosis drugs and careful follow-up being necessary for patients with relevant risk factors.

• Journal of Soil and Groundwater Environment
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• v.14 no.5
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• pp.41-50
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• 2009

Water levels in groundwater monitoring wells of Jeju Island were analyzed using parametric and non-parametric trend analyses. Number of used monitoring wells in the analysis are 94 among totally 106 monitoring wells and the monitoring period is greater than single year, from 2001 to 2009. For the trend analysis, both parametric (linear regression) and nonparametric (Mann-Kendall trend test and Sen's trend test) methods were adopted. Results of the linear regression analysis on daily basis indicated that about 58.5% of the monitoring wells showed a decreasing trend, and analysis using monthly median indicated that about 79.8% showed a decreasing trend. The Mann-Kendall trend test and Sen's trend test with monthly median values in confidence levels of 95% and 99% showed the same analysis results. In confidence level of 95%, 32% were decreased, 3% were increased and the remains showed no trend. However, in confidence level of 99%, 16% were decreased, 2% were increased and the remains showed no trend. The largest decline rates of water levels were detected mainly at the coast of the northwestern and southwestern parts, which is expected to closely related to the increased pumping in the urban area and tourist resort.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8855-8859
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• 2014

Purpose: To investigate the impact of hyperglycemia during inductive treatment on the prognosis of acute lymphocytic leukemia (ALL) in children. Materials and Methods: Clinical data of 159 ALL childhood cases were reviewed. The patients were divided into the hyperglycemia group (fasting $glucose{\geq}126mg/dl$ and/or random blood $glucose{\geq}200mg/dl$) and the euglycemia group according to the blood glucose values. The X2 test was performed to compare the complete remission rates of the two groups, and Kaplan-Meier and log-rank tests were performed to compare the 5-year overall and relapse-free survival. Results: The incidence of hyperglycemia in the $age{\geq}10-year-old$ group was higher than the younger-age group (P=0.009). Values in the interim- and high-risk groups were higher than the standard-risk group (P=0.028), while there was no significant difference between genders (P=0.056). The complete remission rates of the 2 groups demonstrated no significant difference (P=0.134), while the 5-year OS of the hyperglycemia group was lower than in the euglycemia group ($83.8{\pm}6.0%$ vs $94.9{\pm}2.4%$, P=0.014). The 5 -year RFS was significantly lower than the euglycemia group ($62.9{\pm}8.7%$) vs $80.2{\pm}9.1%$, P<0.001). Conclusions: Children with $age{\geq}10year$ old, and in the middle- and high-risk groups appear prone to complicating hyperglycemia during inductive chemotherapy, associated with lower 5-year OS and RFS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.65-77
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• 2008

The effects of climatic changes owing to urbanization, geographical and topographical conditions on annual and monthly FAO Penman-Monteith (FAO P-M) reference evapotranspiration, and energy and aerodynamic terms of FAO P-M reference evapotranspiration were studied. In this study, 21 climatological stations were selected. The statistical methods applied for trend analysis are Spearman rank test, Sen's test, linear regression analysis and analysis of actual variation ratio. Furthermore, the cluster analysis was applied to cluster 21 study stations by considering the geographical and topographical characteristics of study area. The study results indicate that urbanization affects the trend and amount of FAO P-M reference evapotranspiration, energy term and aerodynamic term; however, the result of Sen's test indicates that urbanization does not significantly affect the magnitude of trend (Sen's slope). The energy term increased at study stations located in coastal area; however, decreased at study stations located in inland area. The topographical slope of study area did not significantly influence on the trend of energy term. The aerodynamic term increased in both coastal area and inland area, indicating much significantly increasing trend in inland area, and it was also affected by the topographical slope of the study area.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.551-557
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• 2015

Background: Differentiating morphologic features based on hematoxylin-eosin (HE) staining is the most common method to classify pathological subtypes of non-small-cell lung cancer (NSCLC). However, its accuracy and inter-observer reproducibility in pathological diagnosis of poorly differentiated NSCLC remained to be improved. Materials and Methods: We attempted to explore the role of immunohistochemistry (IHC) staining in diagnosing pulmonary squamous cell carcinoma (SQCC) with poorly differentiated features by HE staining or with elevated serum adenocarcinoma-specific tumor markers (AD-TMs). We also compared the difference of epidermal growth factor receptor (EGFR) mutation rate between patients with confirmed SQCC and those with revised pathological subtype. Logistic regression analyses were used to test the association between different factors and diagnostic accuracy. Results: A total of 132 patients who met the eligible criteria and had adequate specimens for IHC confirmation were included. Pathological revised cases in poor differentiated subgroup, biopsy samples and high-level AD-TMs cases were more than those with high/moderate differentiation, surgical specimens and normal-level AD-TMs. Moreover, biopsy sample was a significant factor decreasing diagnostic accuracy of pathological subtype (OR, 4.037; 95% CI 1.446-11.267, p=0.008). Additionally, EGFR mutation rate was higher in patients with pathological diagnostic changes than those with confirmed SQCC (16.7% vs 4.4%, p=0.157). Conclusions: Diagnosis based on HE staining only might cause pathological misinterpretation in NSCLC patients with poor differentiation or high-level AD-TMs, especially those with biopsy samples. HE staining and IHC should be combined as pathological diagnostic standard. The occurrence of EGFR mutations in pulmonary SQCC might be overestimated.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1099-1103
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• 2010

본 연구에서는 기후변화로 인한 부산 강우특성을 고려하고 강수량의 증감을 알아보기 위하여 부산 기상청 지점의 강우 자료를 수집하고 분석하여 월, 계절, 연 평균강우와 지속시간별 연최대 강우량 및 강우강도(30 mm 이상)를 Trend 분석하였다. 분석기법은 T Test, Hotelling Pabst Test, Non Linear Test, Mann-Kendall Test, Sen Test이고 0.99, 0.95, 0.90의 유의수준별로 분석하였다. 분석된 결과는 1등급에서 4등급까지 등급화하고, 특히 Sen Test의 Slope는 빈도분석하여 등급화하였다.