• Korean Journal of Child Education & Care
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• v.18 no.2
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• pp.85-102
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• 2018

The purpose of this study is to determine the working conditions and demands of the assistant workforce at childcare centers, and to provide suggestions on policies for childcare teachers. To achieve the purpose of the study, a total of 190 assistant teachers, nursing helpers, alternative teachers and others were surveyed online during the month of August 2017. The survey examined the employment route and working motives, working conditions and environment, job and educational difficulties for analyzing the work conditions and demands of ancillary staff. For the analysis method, SPSS 12.0 was used to analyze frequency and difference. The main findings are as follows. First, childcare center assistants were able to work at their respective times, making it mandatory for them to enter the workforce, and making job openings for ancillary teachers. Second, 73.7% said the daily working hours were '4 hours to 8 hours' under the conditions and 57.9% said 'More than 510,000 won to less than 1 million won.' Average amount of rest time per day was about 30 minutes, and 17% had no rest periods. Third, based on the job and education status, ancillary personnel performed "infant and child guidance and interaction", "Cleaning and cleanliness related tasks" most actively, and "care for cleaning and cleanliness" and "care for morning and night care". Fourth, in the job trouble and difficulty, ancillary staff found it difficult to satisfy with wage related complaints and job insecurity, and the reason for agreeing to the non-regular workforce becoming a regular worker was found to be due to the stability of employment. Lastly, the most urgent tasks to solve the problem of non-regular workers were to fill the wage gap between regular and irregular workers, shorten the working hours and improve the working conditions. The policy implications are presented based on the above findings.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.181-188
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• 2014

In this study, an interactive analysis considering column-pile interaction is performed on the basis of an equivalent base spring model for supplementing virtual fixed point design of bent pile structures. Through this analytical method, the application of the minimum steel reinforcement ratio of the pile (0.4%) is analyzed by taking into account the major influencing parameters. Furthermore, the limit depth for steel reinforcement ratio is proposed through the relationships between column and pile conditions. To obtain the detailed information, it is found that an interactive analysis is intermediate in theoretical accuracy between the virtual fixed point model analysis and full-modeling analysis. Base on this study, it is also found that the maximum bending moment is located within cracking moment of the pile when material nonlinearity is considered. Therefore, the minimum steel reinforcement ratio is appropriately applicable for the optimal design of bent pile structures. Finally, the limit depth for steel reinforcement ratio ($L_{As=x%}$) is proposed by considering the field measured results. It is shown that the normalized limit depth ratio for steel reinforcement ratio ($L_{As=x%}/L_P$) decreases linearly as the length-diameter ratio of pile ($L_P/D_P$) increases, and then converges at a constant value.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.16-33
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• 2012

The aim of this study is to estimate aboveground biomass carbon stocks using ordinary kriging(OK) which is the most commonly used type of kriging and regression kriging(RK) that combines a regression of the auxiliary variables with simple kriging. The analysis results shows that the forest carbon stock in Danyang is estimated at 3,459,902 tonC with OK and 3,384,581 tonC with RK in which the R-square value of the regression model is 0.1033. The result of RK conducted with sample plots stratified by forest type(deciduous, conifer and mixed) shows the lowest estimated value of 3,336,206 tonC and R-square value(0.35 and 0.18 respectively) is higher than that of when all sample plots used. The result of leave-one-out cross validation of each method indicates that RK with all sample plots reached the smallest root mean square error(RMSE) value(22.32 ton/ha) but the difference between the methods(0.23 ton/ha) is not significant.

• The Korean Journal of Financial Management
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• v.7 no.1
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• pp.1-20
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• 1990

In most of studies on market efficiency, the stability of risk measures and the normality of residuals unexplained by the pricing model are presumed. This paper re-examines stock splits, taking the possible violation of two assumptions into accounts. The results does not change the previous studies. But, the size of excess returns during the 2-week period before announcements decreases by 43%. The results also support that betas change around announcements and the serial autocorrelation of residuals is caused by events. Based on the results, the existing excess returns are most likely explained as a compensation to old shareholders for unwanted risk increases in their portfolio, or by uses of incorrect betas in testing models. In addition, the model suggested in the paper provides a measure for the speed of adjustment of the market to the new information arrival and the intensity of information contents.

• The Korean Journal of Archival Studies
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• no.34
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• pp.57-105
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• 2012

The CAMS(Central Archives Management System) of NAK(National Archives of Korea) is an important system which receives and manages large amount of electronic records annually from 2015. From the point of view in database design, this paper analyzes the database schema of CAMS and discusses the direction of overall improvement of the CAMS. Firstly this research analyzes the tables for records and folders in the CAMS database which are core tables for the electronic records management. As a result, researchers notice that it is difficult to trust the quality of the records in the CAMS, because two core tables are entirely not normalized and have many columns whose roles are unknown. Secondly, this study suggests directions of normalization for the tables for records and folders in the CAMS database like followings: First, redistributing the columns into proper tables to reduce the duplication. Second, separating the columns about the classification scheme into separate tables. Third, separating the columns about the records types and sorts into separate tables. Lastly, separating metadata information related to the acquisition, takeover and preservation into separate tables. Thirdly, this paper suggests considerations to design and manage the database schema in each phase of archival management. In the ingest phase, the system should be able to process large amount of records as batch jobs in time annually. In the preservation phase, the system should be able to keep the management histories in the CAMS as audit trails including the reclassification, revaluation, and preservation activities related to the records. In the access phase, the descriptive metadata sets for the access should be selected and confirmed in various ways. Lastly, this research also shows the prototype of conceptual database schema for the CAMS which fulfills the metadata standards for records.

• The Korean Journal of Applied Statistics
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• v.33 no.4
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• pp.395-407
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• 2020

Most classification accuracy measures for optimal threshold are divided into two types: one is expressed with cumulative distribution functions and probability density functions, the other is based on ROC curve and AUC. Unal (2017) proposed the index of union (IU) as an accuracy measure that considers two types to get them. In this study, ten kinds of accuracy measures (including IU) are divided into six categories, and the advantages of the IU are studied by comparing the measures belonging to each category. The optimal thresholds of these measures are obtained by setting various normal mixture distributions; subsequently, the first and second type of errors as well as the error sums corresponding to each threshold are calculated. The properties and characteristics of the IU statistic are explored by comparing the discriminative power of other accuracy measures based on error values.The values of the first type error and error sum of IU statistic converge to those of the best accuracy measures of the second category as the mean difference between the two distributions increases. Therefore, IU could be an accuracy measure to evaluate the discriminant power of a model.

• Journal of Intelligence and Information Systems
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• v.12 no.1
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• pp.95-105
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• 2006

This paper proposes a novel approach to represent the image by using shape descriptor having an information of area. The proposed descriptor is a set of vectors, consists of radius, area and direction parameters in the concentrated center point. Due to the area parameter, we know our descriptor can obtain the information of area. Also, we give an extended shape descriptor to get more detailed representation. To do this, we move the center point of our vision to that point for region of interest. By doing so about all of region of interest, we can get our descriptor for detailed information of the image. From more detailed descriptor, it's natural that it's more efficient fur representation, retrievals and so on. We make it the normalized pattern and expand to improve its quality. The proposed method is invariant to scale, position and rotation. The results show that it can be used efficiently for image representation as we can see in retrievals of silhouette images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7170-7178
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• 2014

This study examined relations of emotional labor, job satisfaction, organizational commitment and turnover intention in nurses. The subjects were 320 nurses in 5 general hospitals. The data was collected using a structured questionnaire from August 1 to 20, 2013 and analyzed with descriptive statistics, t-test, ANOVA, Pearson's correlation, and Hierarchical multiple linear regression analysis. The mean scores of the emotional labor level, job satisfaction level, organizational commitment, and turnover intention was $2.79{\pm}.66$, $3.05{\pm}.48$, $3.00{\pm}.53$, and $3.13{\pm}.66$, respectively. Positive correlations of the turnover intention with emotional labor were found. Negative correlations were observed among salary, job satisfaction, organizational commitment, and turnover intention. These results showed that nurses working at five general hospitals needed to minimize emotional labor to maintain a comparatively high level of job satisfaction, organizational commitment and decrease the turnover intention.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.332-339
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• 2008

This study was carried out to develop the score table for prediction of landslide hazard in Gyeongsangbuk-Do province. It was studied to 172 places landslided in 23 cities and counties of Gyeongsangbuk-Do province. An analyze of the score table for landslide hazard was carried out through the multiple statistics of quantification method (I) by the computer. Factors effected to landslide occurrence quantity were shown in order of slope position, slope length, bedrock, aspect, forest age, slope form and slope. As results of the development of score table for prediction of landslide hazard in Gyeongsangbuk-Do province, total score range was divided that 107 under is stable area (IV class), 107~176 is area with little susceptibility to landslide (III class), 177~246 is area with moderate susceptibility to landslide (II class), above 247 area with severe susceptibility to landslide (I class).

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.41-47
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• 2011

Processing of the raw LiDAR data requires the high-end processor, because data form is a vector. In contrast, if LiDAR data is converted into a regular grid pattern by filltering, that has advantage of being in a low-cost equipment, because of the simple structure and faster processing speed. Especially, by using grid data classification, such as Quadtree, some of trees and cars are removed, so it has advantage of modeling. Therefore, this study presents the algorithm for automatic extraction of ground points using Quadtree and refion growing method from LiDAR data. In addition, Error analysis was performed based on the 1:5000 digital map of sample area to analyze the classification of ground points. In a result, the ground classification accuracy is over 98%. So it has the advantage of extracting the ground points. In addition, non-ground points, such as cars and tree, are effectively removed as using Quadtree and region growing method.