• Resources Recycling
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• v.29 no.1
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• pp.25-34
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• 2020

Electrochemical Quartz Crystal microbalance is a tool that is capable of measuring nanogram-scale mass change on electrode surface. When applying alternating voltage to the quartz crystal with metal electrode formed on both sides, a resonant frequency by inverse piezoelectric effect depends on its thickness. The resonant frequency changes sensitively by mass change on its electrode surface; frequency increase with metal dissolution and decrease with metal deposition on the electrode surface. The relationship between resonant frequency and mass change is shown by Sauerbrey equation so that the mass change during metal dissolution can be measured in real time. Especially, it is effective in the case of reaction mechanism and rate studies accompanied by precipitation, volatilization, compound formation, etc. resulting in difficulties on ex-situ AA or ICP analysis. However, it should be carefully considered during EQCM experiments that temperature, viscosity, and hydraulic pressure of solution, and stress and surface roughness can affect on the resonant frequency. Application of EQCM was shown as a case study on leaching of platinum using aqueous chlorine for obtaining activation energy. A platinum electrode of quartz crystal oscillator with 1000 Å thickness exposed to solution was used as leaching sample. Electrogenerated chlorine as oxidant was purged and its concentration was controlled in hydrochloric acid solution. From the experimental results, platinum dissolution by chlorine is chemical reaction control with activation energy of 83.5 kJ/mol.

• Journal of Korean Library and Information Science Society
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• v.50 no.1
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• pp.23-41
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• 2019

This study understand the subject domain of book which has been read by men and woman elderly by analizying the PFNET using library big data and confirm the difference between adult at age 30-40. This study extract co-occurrence matrix of book lending on the popular book list from library big data, for 4 group, men/woman elderly, men/woman adult. With these matrix, this study performs FP network analysis. And Pearson Correlation Analysis based on the Triangle Betweenness Centrality calculated on the loan book was performed to understand the correlation among the 4 clusters which has been created by PNNC algorithm. As a result, reading trend which has been focused on modern korean novel has been revealed in elderly regardless gender, among them, men elderly show extreme tendency concentrated on modern korean long series novel. In the correlation analysis, the male elderly showed a weak negative correlation with the adult male of r = -0.222, and the negative direction of all the other groups showed that the tendency of male elderly's loan book was opposite.

• Journal of Technology Innovation
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• v.31 no.3
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• pp.139-169
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• 2023

This study analyzes the effects of firms' technology innovation(patent applications) on employment(number of workers and proportion of high-skilled workers) and corporate performance(sales per worker), while considering the two-way causal relationships between these variables. We used the three-stage least squares(3SLS) estimation to examine system of equations in which the dependent variables affect each other with a two-year lag wherever relevant, and applied it to firm-level panel data of Korean manufacturers with 100 or more workers. Our data covered the period of 2005-2017. Exogenous variables, such as firms' managerial and other characteristics, were controlled as explanatory variables. The identification variables for each equation included firms' R&D intensity, labor cost per worker(or operation of firms' own R&D center), and investment on worker training. We find that firms' patent applications increased number of workers, proportion of high-skilled workers, and sales per worker; the causal relationships in the opposite direction were also significant. Evidently, firms' technology innovation is critical to the growth and quality improvement of employment as well as sustainable corporate growth.

• Journal of Agricultural Extension & Community Development
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• v.21 no.4
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• pp.1029-1060
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• 2014

The purpose of this study are to figure out whether there are the meaningful differences between learner's learning achievements and contents preference in accordance with the delivery strategies (instructor-focused model, learner-focused model) of learning materials suggested by Bloom in web-based instruction, and to suggest the various options on the contents delivery strategies to improve the learner's learning achievements of each learning domains. Learning domains were divided by the cognitive domain, the affective domain, and the psychomotor domain. The result of research with 182 learners showed that learner-focused model in the cognitive domain caused higher learning achievements and preference than instructor-focused model. And instructor-focused model in the psychomotor domain compared with learner-focused model caused higher learning achievements and preference. However, there were less meaningful differences in the affective domain. In other words, learner-focused model is appropriate to the feature of the cognitive domain while instructor-focused model is appropriate to the feature of the psychomotor domain. The results suggest that delivery strategies should be chosen by domains of learning contents in order to improve learner's learning achievements in web-based instruction. Learner-focused delivery strategies in the cognitive domain and instructor-focused delivery strategies in the psychomotor domain need to be considered positively. Delivery strategies should be studied and developed in order to lead higher learning achievements and preference.

• The Journal of the Korea Contents Association
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• v.15 no.11
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• pp.524-533
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• 2015

This study aims to prove the value of SNS tourism information by confirming the relation between SNS tourism information and perceived risk and by verifying its influence on the intention to switch tourism destination. The data was collected from 302 tourists. For data analysis, SPSS 18.0 program and AMOS 18.0 were conducted. First, functional characteristics of SNS tourism information have been verified to have no relationship with the tourist's perception of risk, and therefore the functional tourism information is thought to cause individual motive regardless of tourist's perception of risk. Second, aesthetic value and economic benefits of SNS tourism information have been analyzed to reduce perceived risk of tourists. Third, a symbol of SNS Tourism information has proved to be an element that increases the risk perceived by tourists, indicating that various kinds of tourism information provided by other channels including SNS can serve as a momentum to make tourists recognize new risks the other way round as new tourism information is accumulated, which acts as new motivating factor.

• Korean journal of communication and information
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• v.63
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• pp.53-75
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• 2013

This study looks into Dooriban movement, which problematizes the ways in which social movements are carried out in everyday settings in modern Korea. Contrary to traditional social movements, Dooriban movement led by active/independent participants -who are locally situated and culturally sensitized- showed a new way of engaging with political power. Making use of qualitative methodology such as in-depth interviews and participant observation, this research examines the implications of emergent cultural practices that redefine and reconfigure the working mechanisms of social movements in Korea today.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.164-173
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• 2018

The purpose of this study is to investigate the effect of job experience while attending college on the turnover risk in the first job following graduation. Data was obtained from the 2015 Graduates Occupational Mobility Survey (GOMS). Subjects included college graduates under 30 years of age, who graduated from high school and entered college in the same year. The results of this study are as follows: First, students who had job experience while attending school were relatively low in economic characteristics, but showed active employment preparation behavior. Second, there was a significant difference in the characteristics of entry into the labor market according to whether they had job experience while attending school. It was found that the securing their first job of graduates with job experience was shorter, and the period of tenure was longer, but their wage was smaller than non-experienced graduates. Third, the Cox regression analysis confirmed what factors affected their employment period, and that job experience, experience frequency, and experience period while attending school had a positive effect on lowering turnover risk. Therefore, this study found that job experience during schooling years makes the employment period of the job longer after graduation, which is consistent with those who had previous job experience. However, the greater amount of job experience during the period of study positively affects job retention.

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.99-114
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• 2020

Overseas advanced ports are promoting smartification, as well as full automation of the terminals surrounding container terminals. A smart port can be defined as a comprehensive concept that pursues increased operational efficiencies, maximization of profit, efficient use of energy, and construction of eco-friendly ports with the introduction of fourth-industrial-revolution technology, including port automation. However, Korea is making efforts to introduce fourth-industrial-revolution technology into ports, but indications are that they are somewhat insufficient compared to advanced ports abroad. Therefore, this study conducted a survey about operators and users of container terminals in Gwangyang Port by deriving the factors determining the introduction of smart ports, such as cost, service, time, safety, and environment, from previous studies. This study analyzed the factors determining the introduction of smart ports and moderating effects when the adjustment variables of operators and users were applied to the pros and cons. As a result of the analysis, it was found that port operators and users have a moderating effect on cost, time, safety, and environmental factors, but not on service factors. These results indicate that port operators try to reduce costs through efficient operation, time management, and by reducing safety accidents by building smart ports, but analysis showed that the negative effects of smart ports have affected port users. The results of this study were derived through a moderated regression analysis and suggested implications for introducing smart ports in the conclusion.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.76-89
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• 2018

The purpose of this study is to analyze factors affecting a grade maintenance of long-term care service users. Using 2008-2014 long-term care raw data of National Health Insurance Service(NHIS), the predictors were examined through the logistic regression by long-term care beneficiaries of grade. The results showed that there are differences by 3 factor groups and grade groups(1-3 grade). In socio-demographic factors, in the 1, 3 grade, Individuals 64 or younger presented a much higher probabilities of the grade maintenance than those 85 and over. In the 3 grade, people of living alone, resident of rural area presented a much higher probabilities of the grade maintenance than others. In disease factors, In the 1 grade, people with dementia presented a much higher probabilities of the grade maintenance than other 2, 3grades. In the 2 grade, people with stroke, fracture presented a much higher probabilities of the grade maintenance than others. In the 3 grade, people with cancer presented a much higher probabilities of the grade maintenance than others. In service factors, In the 2, 3grade, people having more renewal numbers presented a much higher probabilities of the grade maintenance than others. In the 1 grade, people who use facility benefits for more days presented a much higher probabilities of the grade maintenance than others. In the 2 grade, people who use in-home benefits for more days presented a much higher probabilities of the grade maintenance than others. Based on the finding of study, implications and future research directions were discussed for policy considerations.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.767-773
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• 2024

This study was limited to tying (connecting) knots using rescue ropes, and 5 subjects were selected for the experiment. After performing the correct knot, single-layer knot, figure-8 connecting knot, and fisherman's knot, the speed and convenience of each were analyzed. The results of analyzing the most convenient and fastest rope connecting method in rope tying are as follows. The correct knot and single-layer knot showed similar values of 11.80 seconds and 13.20 seconds, respectively. The figure-8 connecting knot showed significantly higher time of 19.00 seconds, which seems to be because the method of making a loop in the shape of a figure-8 and then inserting the rope along the figure-8 shape took some time to connect the rope. The fisherman's knot showed the lowest time of 9.80 seconds. This method overlaps the rope and forms a sling knot on the left and right, so it seems that the overall result is easy for the subjects to learn because it involves wrapping the rope once and pulling it out in the opposite direction. In an emergency rescue situation, the fisherman's knot is considered to be the most appropriate way to quickly and firmly connect ropes.