• Journal of Korea Water Resources Association
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• v.41 no.11
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• pp.1095-1106
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• 2008

Climate change and global warming are prevalent all over the world in this century and many researchers including hydrologists have studied on the climate change. This study also studied the impact of climate change on streamflows of a basin in Korea. The SWAT model was used to assess the impacts of potential future climate change on the streamflows of the Daecheong Dam Basin. Calibration and validation of SWAT were performed on a monthly basis for the year of 1982-1995 and 1996-2005, respectively. The impact of seven 15-year(1988-2002) scenarios were then analyzed for comparing it to the baseline scenario. Among them, scenario 1 was set to show the result of doubling $CO_2$, scenario 2-6 were set to show the results of temperature and precipitation change, and scenario 7 was set to show the result of the combination of climatologic components. A doubling of atmospheric $CO_2$ concentration is predicted to result in an maximum monthly flow increase of 11 percent. Non-linear impacts were predicted among precipitation change scenarios of -42, -17, 17, and 42 percent, which resulted in average annual flow changes in Daecheong Dam Basin of -55, -24, 25, and 64 percent. The changes in streamflow indicate that the Daecheong Dam Basin is very sensitive to potential future climate changes and that these changes could stimulate the increased period or severity of flood or drought events.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.925-932
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• 2014

If a rotor possesses a high gyroscopic coupling or the running speed is high, the dynamical changes in the rotor become prominent. When active magnetic bearings are used to support such rotors, it is necessary for the bearing controller to take these dynamical changes into consideration. Independent-axis controllers, which are the most commonly used, modulate the bearing force solely based on the sensor output of the same axis. However, this type of controller has difficulties in overcoming the dynamical changes. On the other hand, mixed-axis controllers transform the sensor output into components corresponding to the vibrational modes. A separate controller can then be designed for each vibrational mode. In this way, the controller can be designed based on the dynamics of the rotor. In this paper, we describe a design process for a mixed-axis controller that uses a detailed mathematical model of the system. The performance of the controller is evaluated based on the ISO sensitivity requirements and unbalance response, while considering the change in the system dynamics due to the running speed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.189-197
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• 2006

The influence of leodo Ocean Research Station structure to surrounding atmospheric flow is carefully investigated using CFD techniques. Moreover, the validation works of computational results are performed by the comparison with the observed data of leodo Ocean Research station. In this paper, we performed 3-dimensional CAD modelling of the station, generated the grid system for numerical analysis and carried out flow analyses using Navier-Stokes equations coupled with two-equation turbulence model. For suitable free stream conditions of wind speed and direction, the interference of the research station structure on the flow field is predicted. Beside, the computational results are benchmarked by observed data to confirm the accuracy of measured date and reliable data range of each measuring position according to the wind direction. Through the results of this research, now the quantitative evaluation of the error range of interfered gauge data is possible, which is expected to be applied to provide base data of accurate sea surface wind around research stations.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.596-608
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• 2017

This study was carried out in order to develop and validate the Korean Version of Strengths Scale for individuals with mental illness. The first step taken to develop the scale was to construct sample items for the Strengths Scale using literature research and three focus group interviews of individuals with mental illness. Secondly, two professors of the Social welfare Department of a University and two mental social workers reviewed these sample items to select and compile a final version of the scale. Lastly, the scale's reliability and validity was verified through an empirical study of 478 individuals with mental illness who conduct the survey items. The explanatory factor was that the sample items can be grouped into seven factors. Factor 1 was 'Vocation', Factor 2 was 'Family and Social Support', Factor 3 was 'Optimism', Factor 4 was 'Resources Utilization', Factor 5 was 'Coping Behavior', Factor 6 was 'Leisure', Factor 7 was 'Health'. The Confirmatory analysis showed that the model demonstrated a goodness- of-fit. Finally, the Korean Version of Strengths Scale for individuals with mental illness was developed consisting 40 items and was proposed a mental health social work implications.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.43-54
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• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.209-218
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• 2017

This study examined the influence of social support (social support from family, social support from friends), psychological behavioral characteristics (self-esteem, interpersonal dependency, locus of control), and stress on the depression levels of college students. The study subjects were 546 college students in D city. The survey was conducted using a self-administered questionnaire in October 2015. As a result, the depression levels were significantly higher in the group showing lower family and friends' social support, self-esteem, and locus of control, while it was significantly higher in the group showing higher interpersonal dependency and stress. The depression levels of the subjects showed a negative correlation with family and friends' social support, self-esteem, and locus of control, but a positive correlation with interpersonal dependency and stress. Covariance structure analysis revealed an increase in the depression levels of college students when the awareness of the stress source was higher, and when the awareness of social support or psychological behavioral characteristics was lower. These results suggest that the depression levels of college students would be increased when the social support and psychological behavioral characteristics are low, and when stress is high. In particular, it was influenced much more by stress than other factors. Therefore, to decrease the depression levels of college students, it would be necessary to put efforts to understand their main stress sources and then reduce them.

• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.360-374
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• 2017

This study investigates the effects of trust and distrust on intention to purchase in open markets, based on the ideas derived from previous studies such as coexistence of trust and distrust, and two distinct trustees in open markets-intermediary and sellers. Specifically, this study i) proposes a trust-distrust model of intermediary and sellers, ii) explores the transfer of trust and distrust from intermediary to sellers, and iii) discovers the antecedents of trust and distrust. The empirical validation using Partial Least Squares shows three results as follows. First, trust in intermediary positively affects intention to purchase through the mediated impact of trust in sellers. That is, trust in intermediary transfers to trust in sellers. Second, distrust in intermediary negatively affects intention to purchase through the mediated impact of customers' perceived risk. Third, structural assurance and perceived website quality positively affect trust in intermediary. The results of this research have implications for intermediary firms not only to build trust but also to manage distrust level. However, this study could not identify any antecedent of distrust, so further research for these antecedents will be needed in the future.

• Journal of Distribution Science
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• v.11 no.6
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• pp.59-65
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• 2013

Purpose - Studies of mechanism as a competitive strategy, a relatively new field in the study of strategic management research, has recently drawn the attention of the business management scholars. The literature has so far proposed the subjective-based view, environment-based view, and the resource-based view in its analyses of firm management. Hence, it is highly likely for the firm management to be reasonably thought of as a combination of and interaction among the three key elements of subject, environment, and resources this is the mechanism-based view (MBV). It is reasonable to consider firm management to be the combination of and interaction among the three key elements of subject, environment, and resources. The overall dynamic process that integrates these three elements and creates functional harmony is identified as the mechanism, the principle of firm management. Much of the extant literatures on MBV has mainly focused on case studies, a qualitative approach prone to subjectivity of the researcher, although the intuition from the study may lead to meaningful insights into a firm-specific mechanism. This study's focus is also on case analysis, but it still attempts a quantitative approach in order to reach a scientific and systematic understanding of the MBV. Research design, data, and methodology - I used both a qualitative and quantitative approach to a single model, given the complexity of the innovation processes. I conducted in-depth interviews with POSCO employees-20 from general management, two from human resources, eight from information technology, five from finance and accounting, and five from production and logistics management. Once the innovative events were selected, the interview results were double-checked by the interviewees themselves to ensure the accuracy of the answers recorded. Based on the interview, I then conducted statistical validation using the survey results as well. Results - This study analyzes the building process of innovation and the effect of the mechanism pattern on innovation by examining the case of POSCO, which has survived over the past 21 years. I apply a new analytical tool to study mechanism innovation types, perform a new classification, and describe the interrelationships among the mechanism factors. This process allows me to see how the "Subject"factor interacts with the other factors. I found that, in the innovation process of the adoption stage, Subject had a mediating effect but that the mediating effect of resource and performance was smaller than the effect of Subject on performance alone. During the implementation stage, the mediating effect of Subject increased. Conclusion - Therefore, I have confirmed that the subject utilizes resources reasonably and efficiently. I have also advanced mechanism studies: whereas the field's research methods have been largely confined to single case studies, I have used both qualitative and quantitative methods to examine the relationships among mechanisms.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.3
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• pp.245-251
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• 2016

The objective of this study was to externally validate a new dosing scheme for busulfan. Thirty-seven adult patients who received busulfan as conditioning therapy for hematopoietic stem cell transplantation (HCT) participated in this prospective study. Patients were randomized to receive intravenous busulfan, either as the conventional dosage (3.2 mg/kg daily) or according to the new dosing scheme based on their actual body weight (ABW) ($23{\times}ABW^{0.5}mg\;daily$) targeting an area under the concentration-time curve (AUC) of $5924{\mu}M{\cdot}min$. Pharmacokinetic profiles were collected using a limited sampling strategy by randomly selecting 2 time points at 3.5, 5, 6, 7 or 22 hours after starting busulfan administration. Using an established population pharmacokinetic model with NONMEM software, busulfan concentrations at the available blood sampling times were predicted from dosage history and demographic data. The predicted and measured concentrations were compared by a visual predictive check (VPC). Maximum a posteriori Bayesian estimators were estimated to calculate the predicted AUC ($AUC_{PRED}$). The accuracy and precision of the $AUC_{PRED}$ values were assessed by calculating the mean prediction error (MPE) and root mean squared prediction error (RMSE), and compared with the target AUC of $5924{\mu}M{\cdot}min$. VPC showed that most data fell within the 95% prediction interval. MPE and RMSE of $AUC_{PRED}$ were -5.8% and 20.6%, respectively, in the conventional dosing group and -2.1% and 14.0%, respectively, in the new dosing scheme group. These findings demonstrated the validity of a new dosing scheme for daily intravenous busulfan used as conditioning therapy for HCT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.208-217
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• 2018

This study was designed to examine the influence of academic stress, anxiety, interpersonal dependency, and hopelessness on female high school students and their level of depression. The study subjects were 684 students attending an all-female high school in C city. Data were collected by self-administered questionnaires between November 1st, 2016 and December 31st, 2016. The data were analyzed using the SPSSWIN(ver. 21.0) program. The mean values of the level of depression were analyzed by the t-test and ANOVA. The correlation coefficientswereobtained by Pearson correlation analysis and acovariance structure analysis was performed on the factors affecting the level of depression. It was found that the level of depression among all of the subjects was significantly higher within the group with a higher level of academic stress, anxiety, interpersonal dependency, and hopelessness. Thus, the level of depression was positively correlated with the levels of academic stress, anxiety, interpersonal dependency, and hopelessness. The factor that had the most influence on depression was the anxiety factor, followed by interpersonal dependency and academic stress. This result suggests that the level of depression in female high school students has a causal relationship with academic stress, anxiety, interpersonal behavioral characteristics, and hopelessness. Therefore, the most effective strategy to reduce the level of depression among female high school students would appear to be efforts to decrease their academic stress, anxiety, and interpersonal dependency.