• Geomechanics and Engineering
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• v.37 no.4
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• pp.395-418
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• 2024

The epicentral region of earthquakes is typically where liquefaction-related damage takes place. To determine the maximum distance, such as maximum epicentral distance (R_e), maximum fault distance (R_f), or maximum hypocentral distance (R_h), at which an earthquake can inflict damage, given its magnitude, this study, using a recently updated global liquefaction database, multiple ML models are built to predict the limiting distances (R_e, R_f, or R_h) required for an earthquake of a given magnitude to cause damage. Four machine learning models LSTM (Long Short-Term Memory), BiLSTM (Bidirectional Long Short-Term Memory), CNN (Convolutional Neural Network), and XGB (Extreme Gradient Boosting) are developed using the Python programming language. All four proposed ML models performed better than empirical models for limiting distance assessment. Among these models, the XGB model outperformed all the models. In order to determine how well the suggested models can predict limiting distances, a number of statistical parameters have been studied. To compare the accuracy of the proposed models, rank analysis, error matrix, and Taylor diagram have been developed. The ML models proposed in this paper are more robust than other current models and may be used to assess the minimal energy of a liquefaction disaster caused by an earthquake or to estimate the maximum distance of a liquefied site provided an earthquake in rapid disaster mapping.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.1-8
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• 2015

The data of fair value hierarchy is expected to contain different degree of measurement error, information asymmetry, and information risk by the level of hierarchy. Thus, this study examines how hierarchy of fair value discriminately influences on companies' cost of capital. Through regression analysis of corporations listed from 2011 to 2014, it turns out that the regression coefficient of level 1 and 2 of fair value variable vary their rank by cost of capital types, while level 3 contains the highest regression coefficient for every cost of capital variable. In addition, further study of how the relevance between cost of capital and the fair value hierarchy gets affected by market risk management level and audit quality finds no consistent results. However, by analyzing the effect of coincident interaction through the convergence of market risk management and audit quality, when audit quality and market risk management level are high, the effect of relieving cost of capital of Level 3 gets the highest. In conclusion, fair value hierarchy data seems to affect discriminately on cost of capital by involved information risk, and the information risk could decrease by the level of market risk management and audit quality.

• Journal of the Korean Data and Information Science Society
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• v.23 no.2
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• pp.257-269
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• 2012

Global crisis expedites the change in the environment of industry and puts small size enterprises in danger of mass bankruptcy. Because of this, domestic small size enterprises is an urgent need of restructuring. Based on the small business data registered in the Credit Guarantee Fund, we estimated the survival probability in the context of the survival analysis. We also analyzed the survival time which are distinguished depending on the types of business in the small business. Financial variables were also conducted using COX regression analysis of small businesses by types of business. In terms of types of business wholesale and retail trade industry and services were relatively high in the survival probability than light, heavy, and the construction industries. Especially the construction industry showed the lowest survival probability. In addition, we found that construction industry, the bigger BIS (bank of international settlements capital ratio) and current ratio are, the smaller default-rate is. But the bigger borrowing bond is, the bigger default-rate is. In the light industry, the bigger BIS and ROA (return on assets) are, the smaller a default-rate is. In the wholesale and retail trade industry, the bigger bis and current ratio are, the smaller a default-rate is. In the heavy industry, the bigger BIS, ROA, current ratio are, the smaller default-rate is. Finally, in the services industry, the bigger current ratio is, the smaller a default-rate is.

• Radiation Oncology Journal
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• v.19 no.4
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• pp.306-311
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• 2001

Purpose : In this retrospective study, we attempted to evaluate the treatment outcome and the prognostic factors of thymoma treated with surgery, radiotherapy and chemotherapy. Methods and materials : Between 1979 and 1998, 55 patients with thymoma were treated at the Seoul National University Hospital. Of these, 11 patients underwent surgery only, 33 patients received post-operative radiotherapy and 11 patients received radiotherapy only. Twenty-three patients had gross total resection and 21 patients subtotal resection. For postoperative radiotherapy, the radiation dose consisted of $41.4\~55.8\;Gy$. The average follow-up was 64 months, and ranged from 2 to 160 months. The sex ratio was 1:1 and the median age was 48 years $(15\~74\;years)$. Overall survival and disease-free survival were determined via the Kaplan-Meier method, and the log-rank was employed to evaluate for differences in prognostic factor. Results : The five- and 10-year survivai rates were $87\%\;and\;65\%$ respectively, and the median survival was 103 months. By univariate analysis, only stage (p=0.0017) turned out to be significant prognostic factors of overall survival. Also, stage (p=0.0007) was significantly predictive for overall survival in mutivariated analysis. Conclusion : This study showed the stage was found to be important prognostic factors, which influenced survival. Especially, as incomplete resection is related with poor results, complete resection is important to cure the invasive thymoma.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4421-4427
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• 2015

Objectives: To investigate the prognosis significance of preoperative serum alpha-fetoprotein (AFP) and the correlation with clinicopathological factors of hepatocellular carcinoma (HCC) patients who underwent hepatectomy. Materials and Methods: Clinicopathological data of retrospective analysis were collected for 251 HCC patients undergoing hepatectomy in this study. According to preoperative AFP level, patients were categorized into AFP-negative (0-20ng/mL) and AFP-positive (>20 ng/mL) groups for Kaplan-Meier analysis and Cox proportional hazard regression modeling. Results: The results demonstrated that increased AFP was associated with longer prothrombin time (PTs), liver capsule invasion, low grade differentiation, and late Barcelona Clinic Liver Center (BCLC) stage. Moreover, the female patients had a greater prevalence of increased preoperative AFP than male patients [284.8 (3.975-3167.5) vs (3.653-140.65); Z-2.895, p=0.004]. The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 78.1, 57.5, and 40.6 % in the AFP-negative group and 61.8, 37.7, and 31.4 %, respectively, in the AFP-positive group (log-rank test 8.312, p=0.004). The 1-, 3-, and 5-year overall survival (OS) rates were 94.4, 83.8, and 62.3% in the AFP-negative group and 87.2, 60.0, and 36.7%, respectively, in the AFP-positive group. The difference was statistically significant (log-rank test, 16.884, p=0.000). Cox proportional-hazards model identified preoperative AFP to be an independent prognostic predictor of overall survival. Conclusions: Preoperative serum AFP is an independent predictor of prognosis among HCC patients following surgical resection. Female patients have a higher preoperative AFP than their male counterparts.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1038-1045
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• 2006

A series of experiments was conducted to test the compatibilities of two different techniques to determine elemental concentrations by INAA and ICP-MS based on both the NIST SRM 2783(air particulate on filter media) and the field samples for PM10. For NIST SRM the results of INAA were more accurate and precise for all target elements than those of ICP-MS. The comparative data set for PM10 samples collected in an industrial complex area showed that mean of concentration ratio, derived for the two different methods such as C(INNA/ICP-MS), were distinguished from each other: (1) Ba, Cu, K Mg, Na, and Sb: $0.9{\sim}1.1$; (2) Al, Co, Fe, and Mn: $0.8{\sim}1.2$; and (3) Se, Ti, and Zn: >1.3. When the results obtained from both methods were evaluated in terms of regression analysis, paired t-test, and Wilcoxon signed-rank test, the results of many elements determined from PM10 samples(such as Al, Ba, Co, Cu, Fe, K, Mn, Nd, and Sb) exhibited a fairly good agreement between the two methods, despite a wide range of variation.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5033-5036
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• 2012

Objective: To study the relationship between expression of $p57^{KIP2}$ and prognosis and other clinicopathological parameters in invasive breast cancers. Methods: We assessed the expression of $p57^{KIP2}$ in 89 cases of invasive breast cancer and 20 cases of normal breast tissue by immunohistochemical methods and analyzed the results with SPSS software (ver. 16.0). Result: The positive expression rates of $p57^{KIP2}$ protein in the invasive breast cancers and surrounding normal tissue were 30.3% (27/89) and 65% (13/20), respectively. Cases with no $p57^{KIP2}$ expression exhibited a significantly higher post-operative distant metastasis rate than those with $p57^{KIP2}$ expression (37.9% vs. 14.8%; P = 0.01). DFS analysis showed that $p57^{KIP2}$-/C-erbB-2+ tumors also exhibited a significantly higher post-operative distant metastasis rate than the other groups (66.7% vs. 29.2%; P = 0.007), as did $p57^{KIP2}$-/p53+ tumors (64.3% vs. 22.7%; P = 0.001). Survival analysis revealed that $p57^{KIP2}$ was associated with breast cancer-specific survival overall (P = 0.045, log-rank test). Subgroup analysis demonstrated that individuals with $p57^{KIP2}$-/C-erbB-2+tumors experienced significantly worse post-operative survival than those with $p57^{KIP2}$-/C-erbB-2- or other tumors (P = 0.006, log-rank test). $p57^{KIP2}$-/p53+ tumors were associated with significantly worse post-operative survival than $p57^{KIP2}$-/p53- or other tumors (P = 0.001, log-rank test). Cox regression analysis showed that $p57^{KIP2}$ was a non-independent prognostic factor for breast cancer (P = 0.303). Conclusions: $p57^{KIP2}$ is expressed at low levels in invasive breast cancer and is associated with better overall survival rate and disease-free survival in breast cancer patients, but it was a non-independent prognostic factor for breast cancer. Thus, the connection between $p57^{KIP2}$/p53 and $p57^{KIP2}$/C-erbB-2 may provide biomarkers for breast cancer.

• Korean Journal of Forensic Psychology
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• v.12 no.1
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• pp.15-33
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• 2021

In this study, we analyzed the difference in survival rates of those subject to electronic supervision of sex crimes based on the tracking of the period of recidivism and whether they were recidivism, and wanted to confirm the ability of the criminal record to predict recidivism. The criteria for recidivism were defined as cases where a conviction was confirmed due to a criminal case that occurred during the execution of electronic monitoring, and the date of recidivism was the date of occurrence of a case that was confirmed guilty. A total of 122 re-offenders were used in the analysis, and all of them were charged with electronic supervision for committing sex crimes. Studies have confirmed that the subjects commit the most recidivism within three years. In addition, in this study, the difference in survival rate between groups was analyzed after classifying mixed and sex recidivism cases. The number of members was 88 for the mixed recidivism group and 34 for the sex recidivism group. The analysis confirmed that both groups had the most recidivism within three years. There was a slight difference between the survival rate of the mixed recidivism group and the survival rate of the sex recidivism group. So the Log Rank Test and the Generalized Wilcoxon Test were conducted, but no statistically significant differences were identified(Wilcoxon statistic = 2.326, df = 1, p = .13, Log Rank = 1.345, df = 1, p = .25). Next, a Cox Regression analysis was performed to confirm the ability of the criminal record to predict recidivism. As a result, the number of criminal records(sex offense, violent crime) have been confirmed to be a good predictor of recidivism(X²=27.33, df=1, p< .001). As a result, the recidivism rate is gradually decreasing due to the implementation of the electronic monitoring. However, the duration of recidivism required by sex offenders in high-risk groups was found to be rather short. Currently, security measures against felons are being strengthened, so it is necessary to select high-risk groups. Therefore, based on the related studies, the characteristics of high-risk groups and the results of recidivism studies will be used as a basis for disposal within the criminal justice system, which will play a major role in granting objectivity.

• The Korean Journal of Emergency Medical Services
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• v.15 no.3
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• pp.19-30
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• 2011

Purpose : The purpose of this study is to identify the correlations between the ego-states of the 119 emergency medical technicians(119 EMTs) and the burnout and help them grow as a profession. Method : This is a descriptive study and the subjects of this study were 81 EMTs in 119 fire station in G City. This study tried to reveal the burnout in 119 EMTs in accordance with ego-state. Results : The highest score of 119 EMTs was the Nutrition Parent(NP) which showed $32.90{\pm}2.07$. The second highest was of the Critical Parent(CP), $31.95{\pm}2.79$. The Ego-gram profile of 119 EMTs was slope N type. The burnout was $78.90{\pm}13.19$, the physical burnout was highest($28.86{\pm}4.14$) in the low rank territory. The ego state according to level, the comparison of the degree of burnout, Free Child(FC) all but the type of ego-states burnout of the high groups appeared to be much higher. The correlations between their ego-states and the burnout of 119 EMTs appeared to be related to the 'plus(+)' correlation for the Free Child(FC ; r=0.243, p=0.029) and the Adapted Child(AC ; r=0.567, p=0.000), and CP, NP and Adult(A) appeared to be unrelated to the correlation. Results of the regression analysis show that the personal characteristic that has the biggest effect on the burnout of 119 EMTs was the AC(0.717), which seems to have a measurable effect on the statistics(p<0.01). Conclusion : Understanding the personality of 119 EMTs and its the application in the workforce will increase the human resources management system for the fire station officials.

• Proceedings of the Korea Association of Information Systems Conference
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• 1996.11a
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• pp.5-26
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• 1996

This study has two research objectives related to end-user computing (EUC). One of the research objectives was to investigate the current status of EUC of Korean firms. Another research objective was to examine the relationship between individual differences of end-users and EUC success. Using survey data from 752 end-users of 23 firms, the surrent status of EUC and the relationship between individual differences of end-users and EUC success were investigated. The current status of EUC was examined from six perspectives: 1). what is the characteristics of EUC strategy of Korean firms, 2). what are the individual characteristics of end-users in Korean Firms, #0. what are the characteristics of tasks performed by end-users using computer, 4). what are the application a areas of EUC, 5). How end-users are satisfied with the support of firms, 6). what are system usage and satisfaction of end-users. It was also foud that individual differences of end-users are related to EUC success. More specifically, it wat shown that the male gender, younger age, higher level of education, higher rank and organizational tenure, higher math ability, thinking type of cognitive style, positive and optimistic attitudes toward computer, more experience with computer, more computer education and knowledge are individual differences variables associated with EUC success. The results of stepwise regression analysis suggested that the individual difference variables accounted for 14%, 25%, 39% and 30% of the variances of four EUC success variables, satisfaction for outcome, satisfaction for ability, frequency of computer use, and the number of tasks, respectively. These empirical findings suggest that EUC managers should consider individual differences of end-users in managing EUC, such as education, training, support, and human resource management, to maximize potential benefits of EUC.