• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.409-418
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• 2014

The amount of data located in storage servers has dramatically increased with the growth in cloud and social networking services. Storage systems with very large capacities may suffer from poor reliability and long latency, problems which can be addressed by the use of a hybrid disk, in which mechanical and flash memory storage are combined. The Linux-based SSD(solid-state disk) uses a caching technique based on the DM-cache utility. We assess the limitations of DM-cache by evaluating its performance in diverse environments, and identify problems with the caching policy that it operates in response to various commands. This policy is effective in reducing latency when Linux is running in native mode; but when Linux is installed as a guest operating systems on a virtual machine, the overhead incurred by caching actually reduces performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8C
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• pp.689-696
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• 2010

The goal of this paper is to present a novel method for protecting digital image using 2-D cellular automata transform (CAT). A copyright and transform coefficients are used to generate a new content-based copyright and an original digital image is distributed without any hidden copyright. The parameter, which is called gateway value, for 2-D CAT is consisted of rule number, initial configuration, lattice length, number of neighbors, and etc. Since 2-D CAT has various gateway values, it is more secure than conventional methods. The proposed algorithm is verified using attacked images such as filtering, cropping, JPEG compression, and rotation for robustness.

• Asian Journal of Turfgrass Science
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• v.21 no.2
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• pp.177-182
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• 2007

When a football field is constructed using sand medium, the fertilizer management has to be adjusted because of the low nutrient holding capacity and higher leaching rate. The objective of this study was to test the effects of slow release fertilizers on Kentucky bluegrass (Poa pratensis L.) growth in simulated sport field rootzones with PVC pipe pots. Data of turfgrass color, uniformity, growth rate, biomass above ground, and the nitrate content in the leaching solution was collected at different growing stages and during four simulated rain fall periods. The result showed that the nutrient release rate of urea was the highest and that of controlled release nitrogen fertilizer was the lowest. Effects of the controlled release nitrogen fertilizer lasted 14 days more than other lawn fertilizers and 28 days longer than regular urea with acceptable quality levels of turf. The slow release fertilizer also restrained excessive growth of the grass, reduced the times of mowing. Slow release fertilizer used in this study reduced $NO_3$-N leaching by almost 50% at the beginning of turf establishment.

• Korea journal of population studies
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• v.35 no.2
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• pp.73-101
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• 2012

This study attempts to assess the effects of childcare facilities and private education expenses on birth rate and also, to examine whether or not the quality and reliability of childcare facilities affect birth rate. Private education expenses are proxied by the number of private educational institutes or their employees. The study measures the quality and reliability of childcare facilities either by the number of employees per childcare facility or by the ratio of childcare facilities with less than 10 employees to total facilities. Empirical analysis is carried out with a cross-sectional data of 232 areas (si/gun/gu) in 2009. Empirical results indicate that the number of childcare facilities or their employees tended to increase birth rate, while private educational expenses had no effects on birth rate. It appears that the presence of good and reliable childcare facilities contributed to an increase in birth rate. The results provide several policy implications for an increase in fertility.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.101-109
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• 2015

To extend shelf life of mulberry fruits, usually expensive freeze drying of freezing process is required. In this study an economic to multipurpose agricultural products dryers with mulberry dryer and technique was developed to reduce postharvest processing cost. Fuel and electricity consumption for drying were lowest when drying temperature was $60^{\circ}C$. And various drying conditions (fuel 3 hrs, heat 1 hr, room temperature air velocity 51 hrs) of the developed dryer were analyzed to improve drying performance. Dried mulberry fruits had dark brown color and marketable high quality explain the semi-dried characteristics.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.157-168
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• 2021

As a recent global economic trend, the subscription economy is rapidly expanding along with the growth of non-face-to-face online shopping. This study tried to verify the factors influencing online subscription for disposable consumer goods through behavioral reasoning theory. 344 questionnaire responses were collected through a survey in Korea and empirical analysis was performed. As a result of the analysis, value of openness was found to have a positive effect on attitude, reason for adoption and reason against adoption. Reason for adoption showed a positive effect on attitude and adoption intention. Reason against adoption showed a negative effect on attitude but it has no impact on adoption intention. Attitude showed a positive effect on adoption intention. Finally price consciousness and quality barrier was found to the most important factors of reason for adoption and reason against adoption respectively. The results of this study can contribute to subscription companies establishing their marketing strategies. Future research can be conducted with various subscription products and additional variables.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.8
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• pp.566-573
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• 2019

In order to obtain high-quality images by motion compensation in the airborne synthetic aperture radar (SAR), accurate motion sensing in image acquisition section is necessary. Especially, reducing relative position error and discontinuity in motion sensing is important. To overcome the problem, we propose a pre-parametric error modeling (P-PEM) algorithm which is a real-time motion sensing algorithm for the airborne SAR in this paper. P-PEM is an extended version of parametric error modeling (PEM) method which is a motion sensing algorithm to mitigate the errors in the previous work. PEM estimates polynomial coefficients of INS error which can be assumed as a polynomial in the short term. Otherwise, P-PEM estimates polynomial coefficients in advance and uses at image acquisition section. Simulation results show that the P-PEM reduces relative position error and discontinuity effectively in real-time.

• Journal of Convergence for Information Technology
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• v.9 no.1
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• pp.99-104
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• 2019

In an attempt to shed light on the effects of overseas internships on foreign language development, this study investigated the differences in English compositions written by 10 Korean university students who joined an overseas internship program for 15 weeks. For data collection, the participants each wrote an English composition before and after the internship. Data collected was analyzed to discern differences in the two writings, and statistical analyses were carried out of the results. Results showed that the participants appeared to have attained lexical fluency, generating longer sentences embedded with multisyllabic, more diverse types, more complex and less redundant words in more complicated structures after the internship. This study revealed that overseas internships facilitated the growth of linguistic abilities. Korean SMEs need to enhance the global capacity of their human resources via overseas internships to strengthen their global competitiveness, apart from improving their industrial competencies such as productivity and product quality.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.379-387
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• 2020

Purpose: This study aimed to explore methods to improve the quality recognition and satisfaction level of non-face-to-face lectures among students in the departments of dental technology and dental hygiene. Methods: This survey was conducted to assess the status and preference of non-face-to-face lectures and the level of awareness and satisfaction regarding the quality of these lectures among 179 students of dental technology and 295 students of dental hygiene. Statistical analyses were performed using frequency analysis, independent sample t-test, one-way ANOVA (post-hoc Duncan), Welch analysis (post-hoc Games-Howell), and hierarchical multiple regression analysis. Results: Factors that affected the ability to assess the quality of non-face-to-face lectures were the department, the method of non-face-to-face lectures, the most preferred method for conducting lectures, the level of awareness regarding the quality of face-to-face lecture, and satisfaction level. It has 71.5% explanatory power. Moreover, factors that influenced the satisfaction level of non-face-to-face lectures included the department, grade, the highest satisfied non-face-to-face teaching method, the most effective theoretical non-face-to-face teaching method, the most preferred teaching methods, and the ability to assess quality of face-to-face lectures. It has 46.8% explanatory power. Conclusion: Non-face-to-face classes should be designed and developed for web-based programs to improve the motivation and achievement level of the students and encourage interaction between the professors and students. Our findings suggest that educators should strive to achieve optimal educational effects by efficiently combining face-to-face and non-face-to-face lectures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.28-36
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• 2020

In shipbuilding industry, there is conducting most of works by welding at the shipyard, and the volume of welding is increasing with international trends of green ships. Welding joint is guaranteed quality through non-destructive testing (NDT). The manual welding inspection report is produced by identifying the drawings designed, which results in losses the many workforce and occurs human errors. To solve these problems, this paper covers a system that reports on inspection information is automatically generation by input data based on shipbuilding-specific CAD. The developed system analyzes the shape data from drawings of modeling. Also, the system determines welding joints through expansion of the part boundary and generates tag numbers. In addition, it provides the function to automatically extract the information needed for inspection such as weld length, thickness and etc. We conducted test to verify the usefulness of the developed system and confirmed that the welding inspection information extracted through system matches the information shown in drawings of modeling.