• The Journal of Engineering Geology
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• v.29 no.3
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• pp.237-249
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• 2019

The roughness changes on a fracture surface were analyzed via a multi-stage compression test under high temperatures to assess how the cracks in a rock mass affect groundwater movement. The analyzed samples consist of coarse granitic rocks from approximately 40 and 270 m depth, and fine granitic rocks from 500 m depth. The compression test was conducted on $20{\times}40{\times}5mm$ samples using a loading system where the pressure increases in 10 MPa increments to 120 MPa. A high-resolution 3D confocal laser scanning microscope (CLSM) was used to observe the surface changes, including the roughness changes, at each pressure step. The roughness change was calculated based on the roughness factor. The experimental results indicate that the roughness of the fracture surface varies with rock type under the stepwise pressure conditions. These data provide a basis for predicting groundwater flow along rock fractures.

• Journal of the Economic Geographical Society of Korea
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• v.12 no.4
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• pp.364-387
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• 2009

Female marriage immigrants have increased since the mid-1990s in Korea. Thus, their adaptation to Korean society has been a big social issue in Korea. There are a lot of academic researches on their adaptation to Korean society so far. We cannot sufficiently understand general main factors of their adaptation to Korean society because of methodological problems in the studies on the female marriage immigrants. Particularly, there are very few studies on female marriage immigrants' adaptation to their communities. This study analyzes determinants of female marriage immigrants' adaptation to their communities, using stepwise multi-regression. Data are collected from questionary survey on female marriage immigrants in Seoul, Gyeong-gi, Daegu, Gyeong-buk, Gwangju, Jeon-nam. Dependent variables are community life, spatial cognition and activities, and neighborhood relationship. Each dependent variable is analyzed with 30 independent variables through stepwise multi-regression. As a result, 16 positive determinants and 2 negative ones are selected. Positive determinants are resident identity, age, adaptation to home, number of Korean friends and same nationals' friends in Korea and so on. But, Korean language fluence is not selected as a significant factor. This is different from a general recognition. As exiting researches, the importance of social network and adaptation variables is also identified in this study.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.8
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• pp.337-347
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• 2007

An embedded system is called a multi-mode embedded system if it performs multiple applications by dynamically reconfiguring the system functionality. Further, the embedded system is called a multi-mode multi-task embedded system if it additionally supports multiple tasks to be executed in a mode. In this Paper, we address a HW/SW partitioning problem, that is, HW/SW partitioning of multi-mode multi-task embedded applications with timing constraints of tasks. The objective of the optimization problem is to find a minimal total system cost of allocation/mapping of processing resources to functional modules in tasks together with a schedule that satisfies the timing constraints. The key success of solving the problem is closely related to the degree of the amount of utilization of the potential parallelism among the executions of modules. However, due to an inherently excessively large search space of the parallelism, and to make the task of schedulabilty analysis easy, the prior HW/SW partitioning methods have not been able to fully exploit the potential parallel execution of modules. To overcome the limitation, we propose a set of comprehensive HW/SW partitioning techniques which solve the three subproblems of the partitioning problem simultaneously: (1) allocation of processing resources, (2) mapping the processing resources to the modules in tasks, and (3) determining an execution schedule of modules. Specifically, based on a precise measurement on the parallel execution and schedulability of modules, we develop a stepwise refinement partitioning technique for single-mode multi-task applications. The proposed techniques is then extended to solve the HW/SW partitioning problem of multi-mode multi-task applications. From experiments with a set of real-life applications, it is shown that the proposed techniques are able to reduce the implementation cost by 19.0% and 17.0% for single- and multi-mode multi-task applications over that by the conventional method, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.4
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• pp.306-317
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• 2017

Unmanned aerial vehicles (UAVs) became popular platforms for the collection of remotely sensed data in the last years. This study deals with the monitoring of multi-temporal onion growth with very high resolution by means of low-cost equipment. The concept of the monitoring was estimation of multi-temporal onion growth using normalized difference vegetation index (NDVI) and meteorological factors. For this study, UAV imagery was taken on the Changnyeong, Hapcheon and Muan regions eight times from early February to late June during the onion growing season. In precision agriculture frequent remote sensing on such scales during the vegetation period provided important spatial information on the crop status. Meanwhile, four plant growth parameters, plant height (P.H.), leaf number (L.N.), plant diameter (P.D.) and fresh weight (F.W.) were measured for about three hundred plants (twenty plants per plot) for each field campaign. Three meteorological factors included average temperature, rainfall and irradiation over an entire onion growth period. The multiple linear regression models were suggested by using stepwise regression in the extraction of independent variables. As a result, $NDVI_{UAV}$ and rainfall in the model explain 88% and 68% of the P.H. and F.W. with a root mean square error (RMSE) of 7.29 cm and 59.47 g, respectively. And $NDVI_{UAV}$ in the model explain 43% of the L.N. with a RMSE of 0.96. These lead to the result that the characteristics of variations in onion growth according to $NDVI_{UAV}$ and other meteorological factors were well reflected in the model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1681-1689
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• 2010

Several studies on the use of Support Vector Machines (SVMs) for diagnosing rotating machinery have been successfully carried out, but the fault classification depends on the input features as well as a multi-classification scheme, binary optimizer, kernel function, and the parameter to be used in the kernel function. Most of the published papers on multiclass SVM applications report the use of the same features to classify the faults. In this study, simple statistical features are determined on the basis of time domain vibration signals for various fault conditions, and the optimal features for each fault condition are selected. Then, the optimal features are used in the SVM training and in the classification of each fault condition. Simulation results using experimental data show that the results of the proposed stepwise classification approach with a relatively short training time are comparable to those for a single multi-class SVM.

• Journal of Information Technology Services
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• v.11 no.2
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• pp.147-167
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• 2012

In this paper, we attempted to theorize the multi-faceted impacts of smart work on economic activities. In this vein, we adopted socio-economic perspective which includes individual, firm, and social support aspects, and explored the variables related to the quality of life among them. First, smart work patterns are categorized as telework, mobile office, teleconferencing, and social collaboration. And relevant variables are extracted with reference to industrial cases and relevant literatures which investigated economic impacts of digital convergence. Next, with the data collected from experts, following delphi method, validation of variables and explorations of significant factors affecting quality of life were conducted by adopting stepwise regression method. The distinguishing traits of this research are two-folds. The one is the investigation of social support and quality of life aspects of smart work, which has been relatively limited in the digital convergence research field. The other is the comparative analysis of smart work advantages by distinguishing individual and firm aspects separately. The result offers useful insights for socio-economic perspective researches on digital convergence application area.

• Korean Journal of Human Ecology
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• v.11 no.4
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• pp.335-346
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• 2002

The purpose of this study was to investigate how much adolescents use the internet and how much they are addicted to the internet, and to examine the relative effect of the personal and family related variables on the internet addiction. Data was collected through a questionnaire survey given to 420 students of middle school in Kwangju province. The data were analyzed by frequency, percentage, stepwise multi-regression analysis, Cronbach's $\alpha$, and Pearson's correlations coefficient. The major findings obtained from this study were as follows: 1. The proportion of internet addiction of adolescents was 9.1%. 2. Parent's control, positive family emotion and self-efficacy were proved to be the most significant variables. The internet addiction increased as the score of parent's control got higher, and the scores of the positive family emotion and the self-efficacy lower. 3. Because the positive family emotion was found to be a very important factor in determining internet addiction, this research proposes that the further family life education program should be developed to facilitate the normal family functioning in relations with preventing internet addiction.

• Korean Journal of Child Studies
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• v.38 no.2
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• pp.219-232
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• 2017

Objective: The purpose of this study was to investigate the relationships among mothers' play beliefs, children's gender and home play frequency, and their preferences for three types of play. Methods: Totally 256 mothers of 5-year-olds participated in the survey in metropolitan area. Data were analyzed with t-test, Pearson's correlations, and stepwise multi-regression using SPSS 22.0. Results: First, boys and girls showed little difference in their home play experiences. Boys preferred active and rough play, while girls preferred quiet play. Second, mothers' play beliefs and children's home play frequency had partial correlations with children's play preferences. Third, predictors of children's play preferences were influenced by the types of play. Children's gender and mothers' play beliefs affected children's preference for active play. Only gender explained children's preference for rough play. Finally, children's gender, home play frequency, and mothers' play beliefs influence children's preference for quiet play. Conclusion: In conclusion, gender is an important factor of children's play preferences, and mothers' play beliefs and children's home play frequency affect their preferences for a specific type of play.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.3
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• pp.71-76
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• 2007

The fatalities of pedestrian account for about 40.0% of all fatalities in Korea 2005. Vehicle-Pedestrian accident generates trajectory of pedestrian. In pedestrian involved accident, the most important data to inspect accident is throw distance of pedestrian. The throw distance of pedestrian can be influenced by many variables. The variables that influence trajectory of pedestrian can be classified into vehicular factors, pedestrian factors, and road factors. Vehicular factors are the frontal shape of vehicle, impact speed of vehicle, the offset of impact point. Many studies have been done about the relation between impact speed and throw distance of pedestrian. But the influence of the offset of impact point was neglected. The influence of the offset of impact point was analyzed by Working Model, and the trajectory of pedestrian, dynamic characteristics of multi-body were analyzed by PC-CRASH, a kinetic analysis program for a traffic accident. Based on the results, the increase of offset reduced the throw distance of pedestrian. However box type vehicle just like bus, the offset of impact point did not influence the throw distance of pedestrian considerably.

• Journal of the Korean Home Economics Association
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• v.28 no.4
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• pp.155-176
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• 1990

The purpose of this study is to investigate the influential factors to home management ability of mothers and their unmarried daughters through researching the relationship of their home management ability. It would provide the basic data for the direction of Home Economics Education. The subjects were 653, from 20 to 30 years of unmarried women and their mothers in Chonbuk province. The questionaire was used to measure their Home Management ability. The measured areas were planing, creativity, consumption management, housework, evaluation, and human relation. The question items were respectively 6 and totally 36. Spss was used for the statistic. Frequency, Percentage, Means, Standard Deviation were used for general understanding. For data analysis, F-test, Pearson Product-moment Correlation, Duncan's Multiple Range Test, Stepwise Multi-regression Analysis were used. Lastly, the research pattern was examined by Path Analysis. The results were as follows. 1. The importnat influential factors to mother's home management ability were their schooling level and their perceived socio-economic status among the general factors(age, shooling level, perceived socio-economic status) and the family atmosphere factors(monthly income, family type). 2. The important influential factors of unmarried daughter's home management ability were the monthly income of their family and the socio-economic status perceived by them, among their mother's general factors, family atmohphere factors, their own general factors(age, schooling level, perceived socio-economics status, occupation, growing place). 3. The influence of mother's home management ability on unmarried daughter's home management ability was much more remarkable than mother's general factors, family atmosphere factors and unmarried daughter's general factors.