• Quality Improvement in Health Care
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• v.9 no.1
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• pp.74-89
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• 2002

Background : The purpose of this study was to investigate the incidence of unplanned endotracheal extubation and to identify the influencing factor of unplanned extubation in ICUs for providing baseline data in developing prevention strategies and administrative standards. the medical records and hospital information system. In order to analyze factors related to unplanned extubation, the subjects of this study were divided by unplanned extubation group and planned extubation group and were matched by its sex, age, and disease groups in a ratio of one to two. The data were analyzed by descriptive statistics, ${\chi}^2$- test, t-test, Fisher's exact test, and logistic regression analysis with SPSSWIN 10.0 program. Result : 1) Forty-seven(4.99%) of 942 intubated patients experienced unplanned extubation 65 times during the twelve-month period. Thirtyfour( 72.34%) of 47 unplanned extubated patients required reintubation, whereas thirteen patients(27.66%) did not. 2) About half of unplanned extubation(46.8%) occurred during the night shift. 3) As for the nursing activity, respiratory nursing activity score(P=.0.06) and total nursing activity score(P=.011) showed statistically significant differences between unplanned extubation group and planned extubation group. 4) As for the patient status, unplanned extubation group showed more lower consciousness level(P=.000), more irritable or agitated behavior(P=.000), and had more applied physical restraints(P=.000) than planned extubation group. 5) As for the intubation related variables, unplanned extubation group revealed more intubated with respiratory failure(P=.000), more dependent on mechanical ventilation(P=.015) than planned extubation group. 6) Factors affecting unplanned extubations in intensive care unit patients were irritable or agitated behavior(odds ratio=13.757), night shift(odds ratio=7.166), and mechanical ventilation(odds ratio=6.257) from conditional logistic regression analysis. Conclusion : The most affecting factor of unplanned extubation was agitated or irritable behavior. Therefore the results of this study could be helpful to ICU nurses for meticulous care, decision making, timely intervention, and development of intervention strategies for preventing unplanned extubation.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.9
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• pp.381-386
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• 2023

Many existing test case generation researchers extract test cases from models. However, research on generating test cases from natural language requirements is required in practice. For this purpose, the combination of natural language analysis and requirements engineering is very necessary. However, Requirements analysis written in Korean is difficult due to the diverse meaning of sentence expressions. We research test case generation through natural language requirement definition analysis, C3Tree model, cause-effect graph, and decision table steps as one of the test case generation methods from Korean natural requirements. As an intermediate step, this paper generates test cases from C3Tree model-based decision tables using meta-modeling. This method has the advantage of being able to easily maintain the model-to-model and model-to-text transformation processes by modifying only the transformation rules. If an existing model is modified or a new model is added, only the model transformation rules can be maintained without changing the program algorithm. As a result of the evaluation, all combinations for the decision table were automatically generated as test cases.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.1-14
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• 2014

This paper aims at measuring how new information is incorporated into volatility estimates. Various GARCH models are compared and estimated with daily BDI(Baltic Dry Index) data. While most researchers agree that volatility is predictable, they differ on how this volatility predictability should be modelled. This study, hence, introduces the asymmetric or leverage volatility models, in which good news and bad news have different predictability for future. We provide the systematic comparison of volatility models focusing on the asymmetric effect of news on volatility. Specifically, three diagnostic tests are provided: the sign bias test, the negative size bias test, and the positive size bias test. From the Ljung-Box test statistic for twelfth-order serial correlation for the level we do not find any significant serial correlation in the unpredictable BDI. The coefficients of skewness and kurtosis both indicate that the unpredictable BDI has a distribution which is skewed to the left and significantly flat tailed. Furthermore, the Ljung-Box test statistic for twelfth-order serial correlations in the squares strongly suggests the presence of time-varying volatility. The sign bias test, the negative size bias test, and the positive size bias test strongly indicate that large positive(negative) BDI shocks cause more volatility than small ones. This paper, also, shows that three leverage models have problems in capturing the correct impact of news on volatility and that negative shocks do not cause higher volatility than positive shocks. Specifically, the GARCH model successfully reveals the shape of the news impact curve and is a useful approach to modeling conditional heteroscedasticity of daily BDI.

• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.461-479
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• 2006

This paper derives joint and conditional Lagrange multiplier tests based on Double-Length Artificial Regression(DLR) for testing functional form and/or the presence of individual(time) effect in a panel regression model. Small sample properties of these tests are assessed by Monte Carlo study, and comparisons are made with LM tests based on Outer Product Gradient(OPG). The results show that the proposed DLR based LM tests have the most appropriate finite sample performance.

• Korean Journal of Human Ecology
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• v.14 no.1
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• pp.95-105
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• 2005

This study examined the factors affecting college students' money management behaviors according to credit card usage. The data were collected from 481 college students in Busan and Gyeongnam areas by a self-administered questionnaire. Frequencies, Cronbach's Alpha, factor analyses, t-test, Pearson's correlation analysis, and regression analyses were conducted by SPSS WINDOWS. The results from this study were as follows. First, there were significant differences between credit card usage group and non-usage group in the means for future preparation, stingy attitude, and planned expenditure. However, there was no significant difference in the mean of money management behaviors. Second, for the credit card usage group, the significant variables affecting money management behaviors included sex, grade, experience of consumer education, father's occupation, monthly household income, future preparation, stingy attitude, methods of emotional change, planned expenditure, and negative recognition. On the other hand, for the non-usage group, grade, experience of consumer education, father's occupation, way of success, future preparation, stingy attitude, planned expenditure, and conditional permission were significant. These results imply that financial management education including values about money and consumption patterns should be conducted.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.139-145
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• 2019

This study examines the dynamic linkages between food price inflation and its volatility in the context of Sri Lanka. The empirical evidence derived from the monthly data for the period from 2003M1 to 2017M12 for Sri Lanka. The relationship between inflation rate and inflation volatility has attracted more attention by theoretical and empirical macroeconomists. Empirical studies on the relationship between food inflation and food inflation variability is scarce in the literature. Food price inflation is defined as log difference of food price series. The volatility of a food price inflation is measured by conditional variance generated by the FIGARCH model. Preliminary analysis showed that food inflation is stationary series. Granger causality test reveals that food inflation seems to exert positive impact on inflation variability. We find no evidence for inflation uncertainty affecting food inflation rates. Hence, the findings of the study supports the Friedman-Ball hypothesis in both cases of consumer food price inflation and wholesale food price inflation. This implies that past information on food inflation can help improve the one-step-ahead prediction of food inflation variability but not vice versa. Our results have some important policy implications for the design of monetary policy, food policy thereby promoting macroeconomic stability.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.352-357
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• 2003

Creep tests for Titan were carned out using constant-load at $600^{\circ}C$, $650^{\circ}C$ and $700^{\circ}C$. Material constants necessary to predict creep life were acquired from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. It was discovered the log-log plot of M-G relationships between the rupure time(tr) and he minimum creep rate(${\varepsilon}_m$) was conditional on test temperatures. The slop of m was 2.75 at $600^{\circ}C$ and m was 1.92 at $700^{\circ}C$. However; the log-log plot of modified M-G relationships between $t_r/\varepsilon_r$ and $\varepsilon_m$ was indpendent on stresses and temperatures. That is the slop of m' was almost 3.90 in all the data. Thus, change M-G relationships to creep life prediction could be vtilized more reasonably than that of M-G relationships for type Titan. It was divided that the constant slopes never theless of temperatures of practical stresses in the modified relationship were due to an intergranular break grown by wedge-type cauities.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.63-74
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• 2020

This study investigates the behavior of foreign investors in the Stock Exchange of Thailand (SET) in the time of coronavirus disease 2019 (COVID-19) as to whether trading is abnormal, what strategy is followed, whether herd behavior is present, and whether the actions destabilize the market. Foreign investors' trading behavior is measured by net buying volume divided by market capitalization, whereas the stock market behavior is measured by logged return on the SET index portfolio. The data are daily from Tuesday, August 28, 2018, to Monday, May 18, 2020. The study extends the conditional-regression model in an event-study framework and extracts the unobserved abnormal trading behavior using the Kalman filtering technique. It then applies vector autoregressions and impulse responses to test for the investors' chosen strategy, herd behavior, and market destabilization. The results show that foreign investors' abnormal trading volume is negative and significant. An analysis of the abnormal trading volume with stock returns reveals that foreign investors are not positive-feedback investors, but rather, they self-herd. Although foreign investors' abnormal trading does not destabilize the market, it induces stock-return volatility of a similar size to normal trade. The methodology is new; the findings are useful for researchers, local authorities, and investors.

• Tunnel and Underground Space
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• v.17 no.1 s.66
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• pp.9-16
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• 2007

The influence of round length on the tunnel stability and construction cost is well acknowledged by many researchers and engineers but the coherent procedure is not available for its determination. In this study, the behaviour modes of the face and unsupported span was investigated for weak rock tunnel by a small scale model test, PFC3D and FDM analyses in consideration of the round length. Total five types of behaviour modes are defined and quantitative estimation of the behaviour modes was established in terms of the safety factor for the face stability and the conditional chart. Although the proposed method has some restrictions, this method can provide useful information for the optimization of the round length and excavation, especially in design stage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.540-543
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• 2013

This paper describes an implementation of a unified ALU on multi-core GPGPU based on SIMT architecture. Our unified ALU can operate conditional branch instructions, data movement instructions, integer arithmetic instructions and floating-point arithmetic instructions. Since multi-core GPGPU contains a lot of ALU for parallel processing of various types, the main point of this paper is to design the minimum size ALU by unifying similar processing of each operations on circit level. All instrunctions were tested by making a test program. And we compare this results with results of CPU operations to verify our ALU. Our unified ALU's gate size is approximately 20,000 and the maximum operation frequency is 430MHz.