• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.87-101
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• 2012

In gas industries, the potential risks of serious accidents have been increased due to high technology application and process complexities. Especially, in case of gas-related accidents, the extent of demage is out of control since gas plants handle and produce combustible, flammable, explosive and toxic materials in large amounts. The characteristics of this kind of disaster is that accident frequency is low, while the impact of damage is high, extending to the neighboring residents, environment and related industries as well as employees involved. The hydrogen gases treated important things and it used the basic material of chemical plants and industries. Since 2000, this gas stood in the spotlight the substitution energy for reduction of the global warming in particular however it need to compress high pressure(more than 150 bar.g) and store by using the special cylinders due to their low molecular weight. And this gas led to many times the fire and explosion due to leak of it. To reduce these kinds of risks and accidents, it is necessary to improve the new safety management system through a risk management after technically evaluating potential hazards in this process. This study is to carry out the quantitative risk assesment for hydrogen filling plant which are very dangerous(fire and explosive) and using a basic materials of general industries. As a results of this risk assessment, identified the elements important for safety(EIS) and suggested the practical management tools and verified the reliability of this risk assessment model through case study of accident.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.887-892
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• 2019

Many researchers have developed a series of vision-based technologies to monitor construction sites automatically. To achieve high performance of vision-based technologies, it is essential to build a large amount and high quality of training image database (DB). To do that, researchers usually visit construction sites, install cameras at the jobsites, and collect images for training DB. However, such human and site-dependent approach requires a huge amount of time and costs, and it would be difficult to represent a range of characteristics of different construction sites and resources. To address these problems, this paper proposes a framework that automatically constructs a training image DB using web crawling techniques. For the validation, the authors conducted two different experiments with the automatically generated DB: construction work type classification and equipment classification. The results showed that the method could successfully build the training image DB for the two classification problems, and the findings of this study can be used to reduce the time and efforts for developing a vision-based technology on construction sites.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.112-117
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• 2017

Ion exchange fiber, PADD was synthesized by the reaction between PAN based acrylic fiber and DETA with $AlCl_3{\cdot}6H_2O$, and was analyzed by FT-IR and SEM to investigate its characteristics. The experimental results of Cr(VI) removal by PADD were better fitted with Langmuir adsorption isotherm, and the maximum uptake value ($Q_{max}$) was calculated to be 6.93 mmol/g. The kinetic data can be well described by Lagergen pseudo-second order rate model. The Cr(VI) adsorption capacity of PADD was 4.11 mmol/g at pH 2, which shows the effect of pH changes on the removal of Cr(VI). The adsorption selectivity of Cr(VI) was higher than phosphate and As(V). Total ion exchange capacity of PADD was 4.70 mmol/g, which was measured by acid-base back titration.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.385-393
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• 2017

The purpose of this study was to develop and apply the participation-centered lecture model and practice principle developed by the Change Laboratory Method to improve the lecture interaction of nursing education and verify the effect. The experimental group was 91, and control group was 83 students who studied in the 3rd and 4th grade at one College of Nursing, This study developed the detail participatory lecture method on January and February and applied it to the students in March, and April, 2017, In the pre-survey, general characteristics, class attitude, and learning strategies were examined and homogeneity test was conducted. Post-survey was conducted with participation, satisfaction, and performance, The results showed that the experimental group and the control group were homogeneous. The average participation levels of the experimental and control groups were 3.98 and 3.77 respectively(t=2.38, p<.05). However, there was no statistically significant difference in the satisfaction and achievement. Therefore, it was expected to improve the participation and performance of students through the application of the participation-centered lecture. In the future, it will be necessary to prepare and implement effective methods for improvement of teaching methods in each subject.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.10-18
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• 2013

With advancing of mobile communication services and commercializing of VoLTE (Voice of LTE), it is getting to pay attention on QoS of VoLTE. This paper proposes an integrated E-model in which some factors influenced to service quality of VoIP and VoLTE based voice communication system are considered in calculating the voice quality of Wideband Codec. The model aims to calculate R value which reflects the situations of access network, network characteristics, terminals' usage and mobility. We mainly deal with the integrated E-model's structure, related algorithms and optimal parameters for VoLTE. Some experiments show that the voice quality difference between VoIP and VoiceChecker, and VoLTE and POLQA, is below 10%. With the proposed model, we can calculate the voice quality by making use of the factors directly affected to service quality and the environment of VoLTE terminal and network. As a result, we can estimate the service quality in advance, without measuring it in real wireless environment.

• The Journal of the Korea Contents Association
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• v.20 no.2
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• pp.60-81
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• 2020

This research was trying to examine through the technology acceptance model that is expanded in order to make an inquiry the factors having an effect on the acceptance intention of the technology fusion type webtoon user. The survey was carried out for the research for 114 questionnaire respondents where there is the technology fusion type webtoon utilization experience. After and hierarchical regression analysis was performed and the relationship was analyze between the factor. The total 13 hypotheses and one research problems were set and the study with was proceeded. Next, it is same if the results of study is summarized. Firstly, the interactivity and immersion, that is the subordinate factor of the Siljaegam, affected the static influence to the perceived usability. Secondly, with having the static influence an effect on the technology fusion type webtoon use intention the perceived usability was confirmed. Thirdly, the effeciency, Tendency of Conciseness, and consistency were the technology fusion type GUI standard extracted with the Ttamsaekjeok the result subfactor that it analize factor. Finally, with giving the meaningful influence to the perceived easiness the visual unrefined copper steam, that is the subordinate factor of the Siljaegam, was confirmed.

• Journal of Distribution Research
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• v.16 no.1
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• pp.179-222
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• 2011

This research investigates the influence of relational characteristics on 'co-defection', customer defection following salesperson turnover, in the context of salesperson-customer relationship. Based on the social exchange theory, it was hypothesized that perceived relational benefits and switching costs affect directly the customer's intentions to defect. Key constructs in relationship marketing such as customer satisfaction, trust, and loyalty were hypothesized to affect the customer's intention to defect as well as perceived relational benefits and switching costs. The results of structural equation modeling using a survey sample of 503 insurance customers who purchased life insurance policies through salespersons unveiled that the customer satisfaction with salesperson and the customer trust in salesperson strongly influence the salesperson-owned customer loyalty. However, they did not have significant direct effects on co-defection intentions. All paths from salesperson-owned customer loyalty to perceived relational benefits and perceived switching costs were also significant. Salesperson-owned customer loyalty did not have significant direct effects on co-defection intentions, but it had significant indirect effects on co-defection intentions through relational benefits and switching costs. Three sub-dimensions of perceived relational benefits had significant positive effects on co-defection intentions while the perceived switching costs had significant negative effects on co-defection intentions. The significance of our research findings were verified by comparing the hypothesized model and the rival model in the past studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.232-239
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• 2020

The purpose of this study was to identify the effect of stress and sense of coherence on health behavior compliance in patients with stroke. The subjects were 124 outpatients with stroke at a general hospital in Ulsan from May to July, 2019. The data were analyzed using descriptive statistics, t-test, one-way ANOVA, Scheffé test, Pearson's correlation coefficient and hierarchical multiple regression analysis by using SPSS 25.0. In the results, the health behavior compliance showed a significantly positive correlation with sense of coherence(r=.71, p<.001) and a negative correlation with stress(r=-.53, p<.001). The predictors of model 1 were gender(t=4.07, p<.001), education level(t=4.18, p<.001), and monthly income(t=-2.34, p=.021) and the statistical power was 39.6%. The predictors of model 2 were gender(t=4.65, p<.001), education level(t=43.24, p<.001), and sense of coherence(t=4.33, p<.001) and the statistical power was 60.4%. Thus, a nursing intervention program which is focused on a sense of coherence could promote health behavior compliance in patients with stroke.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.760-767
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• 2020

Sustainable growth of hydroelectric power plants is expected in consideration of climate change and energy security. However, hydroelectric power plants always have a risk of water hammer damage, and safety assurance is very important. The water hammer phenomenon commonly occurs during operations such as rapid opening and closing of the valves and pump/turbine shutdown in pipe systems, which is more common in cases of emergency shutdown. In this study, a computational numerical model was developed using the MOC-FDM scheme to reflect the mechanism of water hammer occurrence. The proposed model was implemented in boundary conditions such as reservoir, pipeline, valve, and pump/turbine conditions and then applied to simulate hypothetical case studies. The analysis results of the model were verified using the analysis results at the main points of the pipe systems. The model produced reasonably good performance and was validated by comparison with the results of the SIMSEN package model. The model could be used as an efficient tool for the safety assessment of hydroelectric power plants based on accurate prediction of transient behavior in the operation of hydropower facilities.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.243-252
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• 2017

Since the failure behavior of transversely isotropic rocks is significantly different from that of isotropic rocks, it is necessary to develop a transversely isotropic rock failure function in order to evaluate the stability of rock structures constructed in transversely isotropic rock masses. In this study, a spatial distribution function for strength parameters of transversely isotropic rocks is proposed, which is based on the Cassini oval curve proposed by 17th century astronomer Giovanni Domenico Cassini to model the orbit of the Sun around the Earth. The proposed distribution function consists of two model parameters which could be identified through triaxial compression tests on transversely isotropic rock samples. The original Mohr-Coulomb (M-C) failure function is extended to a three-dimensional transversely isotropic M-C failure function by employing the proposed strength parameter distribution function for the spatial distributions of the friction angle and cohesion. In order to verify the suitability of the transversely isotropic M-C failure function, both the conventional triaxial compression and true triaxial compression tests of transversely isotropic rock samples are simulated. The predicted results from the numerical experiments are consistent with the failure behavior of transversely isotropic rocks observed in the actual laboratory tests. In addition, the simulated result of true triaxial compression tests hints that the dependence of rock strength on intermediate principal stress may be closely related to the distribution of the microstructures included in the rock samples.