• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.721-736
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• 2019

In this paper, the behavior of the fire smoke due to the operation of the ventilation systems when the fire occurred in the underground station (6 basement floors) and the tunnel at the great depth was measured. Fire smoke was generated by using a smoke generator which realized heat buoyancy effect by using hot air blower. The two locations of the fire were selected on the platform and on the platform of the tunnel located outside the screen door. A ventilation mode is generally used in which smoke is exhausted through a vent hole provided in a platform when a platform fire occurs. The tests were performed by operating the exhaust through the ventilation holes of the tunnel part located at both ends of the platform. The smoke density and the wind speed/velocity were measured at various positions, and the videos were taken to analyze the movement and smoke of the smoke. In both cases for fire inside the platform and in the railway tunnel, due to the ventilation mode operation of the fan for the platform and the exhaust of the fans in the tunnel smoke were well exhausted and the smoke propagation to the area near the smoke zone was suppressed. The smoke-control mode, which is applied to both fans for the platform and fans for in the tunnel at both ends of the platform, can provide a safer evacuation environment to the passengers from the fire smoke when the platform fire or fire train stops.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.19-26
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• 2021

The seismic isolation system have been applied in order to protect the collapse of bridge by seismic load and the vertical load transmitted from the superstructure. However, the failure and damages of non-shrinkage mortar, isolator and wedge in total 12 bridge were reported by Pohang Earthquake. In this study, the damage mechanism and behavior characteristics of elastomeric bearing by an earthquake were evaluated to consider the seismic isolation system including non-shrinkage mortar and the seat concrete of pier. To discuss the effect of installed wedge and damage mode of elastomeric bearing, the compressive-shear tests were carried out. Also, the mechanical behaviors and damage mechanism for each component of elastomeric bearing were evaluated by using finite element analysis. From the test results, the cracks were created at boundary between non-shrinkage mortar and seismic isolator and the shear loads were rapidly increased after bump into wedge. The cause for damage mechanism of seismic isolation system was investigated by comparing stress distribution of anchor socket and non-shrinkage mortar depending on wedge during earthquake.

• Journal of the Korean GEO-environmental Society
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• v.22 no.8
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• pp.5-12
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• 2021

Climate change caused by global warming increases the frequency of occurrence of super typhoons and causes various types of sediment disasters such as debris flows in the mountainous area. This study is to evaluate the behavior of debris flow according to the multiplier value of the precipitation characteristics and the quantity of debris flow according to the typhoon category. For the analysis of the debris flow, the finite difference method for time elapse was applied. The larger the typhoon category, the higher the peak value of the flow discharge of debris flow and the faster the arrival time. When the precipitation characteristic multiplier is large, the fluctuation amplitude is high and the bandwidth is wide. When the slope angle was steeper, water discharge increased by 2~2.5 times or more, and the fluctuation of the flow discharge of debris flow increased. All of the velocities of debris flow were included to the class of "Very rapid", and the distribution of the erosion or sedimentation velocity of debris flows showed that the magnitude of erosion increased from the beginning, large-scale erosion occurred, and flowed downstream. The results of this study will provide information for predicting debris flow disasters, structural countermeasures and establishing countermeasures for reinforcing resilience in vulnerable areas.

• Korean Journal of Community Nutrition
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• v.24 no.4
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• pp.300-308
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• 2019

Objectives: This research was conducted to identify the consumers' food choice factors that affect the consumers' replacement of soft drinks with carbonated water. Methods: The present study used secondary data from a consumer panel survey conducted by the Rural Development Administration of Korea, and the data included the panel members' purchase records based on their monthly spending receipts. The survey asked the participants about their food choice factors and their personal responsibility for their health. This survey included independent variables for the consumers' food purchase factors. As a dependent variable, two types of groups were defined. The replacement group included those people who increased their purchase of carbonated water and decreased their purchase of soft drinks. The non-replacement group included those people who did not change their purchase patterns or they increased their purchase of soft drinks and they decreased their purchase of carbonated water. Logistic regression analysis was conducted to determine the consumers' food choice factors that were associated with replacing soft drinks with carbonated water. Results: The replacement group was significantly associated with (1) a younger age (OR=0.953), (2) being a housewife (OR=2.03), (3) higher income (OR=1.001) and (4) less concern about price (OR=0.819) when purchasing food. This group also showed (5) higher enjoyment (OR=1.328) when choosing food and (6) they took greater responsibly for their personal health (OR=1.233). Conclusions: This research is the first study to mainly focus on soft drinks and carbonated water. The result of this research showed that young, health-conscious consumers with a higher income and who are more interested in food have more possibilities to replace soft drinks with carbonated water. These research findings may be applied to consumers who have characteristics that are similar to the young health-conscious consumers and the results can help to suggest ways to reduce sugar intake and improve public health. However, this research has a limitation due to the application of secondary data. Therefore, a future study is needed to develop detailed survey questions about food choice factors and to extend these factors to all beverages, including soft drinks made with sugar substitutes, so as to reflect the growth of alternative industries that use artificial sweeteners or different types of sugar to make commercially available drinks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.439-447
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• 2019

In this study, experiments were conducted to establish appropriate measures for slopes with high risk of collapse and to obtain results for minimizing slope collapse damage by detecting the micro-displacement of soil in advance by installing a laser sensor and a vibration sensor in the landslide reduction model experiment. Also, the behavior characteristics of the soil layer due to rainfall and moisture ratio changes such as pore water pressure and moisture were analyzed through a landslide reduction model experiment. The artificial slope was created using granite weathering soil, and the resulting water ratio(water pressure, water) changes were measured at different rainfall conditions of 200mm/hr and 400mm/hr. Laser sensors and vibration sensors were applied to analyze the surface displacement, and the displacement time were compared with each other by video analysis. Experiments have shown that higher rainfall intensity takes shorter time to reach the limit, and increase in the pore water pressure takes shorter time as well. Although the landslide model test does not fully reflect the site conditions, measurements of the time of detection of displacement generation using vibration sensors show that the timing of collapse is faster than the method using laser sensors. If ground displacement measurements using sensors are continuously carried out in preparation for landslides, it is considered highly likely to be utilized as basic data for predicting slope collapse, reducing damage, and activating the measurement industry.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.30-37
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• 2018

The social media data and the broadcasting data related to onion as well as agri-food consumer panel data were collected and investigated if the amount of money spent to purchase onion in year 2014 when onion price plunged latest were correlated with the frequencies of onion-related keywords in the social media data and the broadcasting programs because onion price in year 2018 is expected to plunge due to overproduction and there has been needs to analyze impacts of social media and broadcasting program on onion purchase in the previous similar events, and identify potential factors that can promote onion consumption in advance. What we identified from our study include a) broadcasting news programs mentioning words "onion," were correlated with onion purchase with 3 - 6 weeks in advance; b) broadcasting entertainment programs mentioning words "onion and health," were correlated with onion purchase with 11 weeks in advance; c) blog mentioning words "onion and efficacy," were correlated with onion purchase with 5 weeks in advance. Our study provided a case on how social media and broadcasting programs could be analyzed for their effects on consumer purchase behavior using big data collection and analysis in the field of agriculture. We propose to use the findings from the study may be applied to promote onion consumption.

• 재활복지
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• v.20 no.4
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• pp.79-106
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• 2016

This study examined the meanings of the disability education of the mothers who reared their children with brain lesions. For this purpose, Rennie's hermeneutic grounded theory was applied and the consented 7 mothers participated in this study. With the in-depth interviews, 53 meaning units, 16 subordinate categories and 7 hermeneutic categories were classified. These 7 hermeneutic categories were 'wailing miserably everyday', 'social mobilization of the surroundings', 'straight forward', 'smash rock with the eggs', 'looking at a faraway', 'learning together' and 'subjectivation of disability education.' The experience of disabled children education process was concurrent experience of frustration and hoping that moving toward a big hope through the resignation stage, the chasing stage, the vision stage, the challenge stage, and the small achievement stage. Repetitive common patterns of behavior revealed three types: wishy-washy type, realistic-strategy type, and indomitable-challenge type. Moreover, the core category of educational experience was concluded to be 'a pedagogical process of turning despair from severe disabilities into hope through education.' Based on the analysis results, concrete intervention plans for social welfare practice were suggested to support the disabled children's lives with high quality of education.

• Convergence Security Journal
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• v.18 no.1
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• pp.117-128
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• 2018

The purpose of this paper is to analyze the behavior of North Korea's cyber attack against South Korea since 2009 based on major international security theories and suggest South Korea's policy option. For this purpose, this paper applied the behavioral domain and characteristics of 'cyber power' and 'coercion dynamics' model, which are attracting attention in international security studies. The types of cyber attacks from North Korea are classified into the following categories: power-based incarceration, leadership attacks and intrusions, military operations interference, and social anxiety and confusion. In terms of types and means of cyber power, North Korean GPS disturbance, the Ministry of Defense server hacking and EMP are hard power with high retaliation and threat and cyber money cashing and ransomware are analyzed by force in the act of persuasion and incentive in the point of robbing or asking for a large amount of money with software pawns. North Korea 's cyber attack has the character of escape from realistic sanctions based on the second nuclear test. It is important for South Korea to clearly recognize that the aggressive cyberpower of North Korea is changing in its methods and capabilities, and to ensure that North Korea's actions result in far greater losses than can be achieved. To do this, it is necessary to strengthen the cyber security and competence to simultaneously attack and defend through institutional supplement and new establishment such as cyber psychological warfare, EMP attack preparation, and enhancement of security expertise against hacking.

• Journal of the Korean Wood Science and Technology
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• v.49 no.3
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• pp.213-225
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• 2021

In this paper, we investigated the carbonization characteristics of lignin hydrochar prepared by hydrothermal carbonization and established a model for predicting the carbonization degree using near-infrared spectroscopy and partial least squares regression. The carbon content of the hydrothermally carbonized lignin at the temperature of 200 ℃ was higher by approximately 3 wt% than that of the untreated sample, and the carbon content tended to gradually increase as the heating time increased. Hydrothermal carbonization made lignin more carbon-intensive and more homogeneous by eliminating the microparticles. The discriminant and predictive models using near-infrared spectroscopy and partial least squares regression approppriately determined whether hydrothermal carbonization has been applied and predicted the carbon content of hydrothermal carbonized lignin with high accuracy. In this study, we confirmed that we can quickly and nondestructively predict the carbonization characteristics of lignin hydrochar manufactured by hydrothermal carbonization using a partial least squares regression model combined with near-infrared spectroscopy.

• Korean Journal of Metals and Materials
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• v.49 no.2
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• pp.167-173
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• 2011

Nickel cobalt ferrite($Ni_{0.5}Co_{0.5}Fe_2O_4$) powder was prepared through the ceramic route by the calcination of a stoichiometric mixture of NiO, CoO and $Fe_2O_3$ at $1100^{\circ}C$. The pressed pellets of $Ni_{0.5}Co_{0.5}Fe_2O_4$ were isothermally reduced in pure hydrogen at $800{\sim}1100^{\circ}C$. Based on the thermogravimetric analysis, the reduction behavior and the kinetic reaction mechanisms of the synthesized ferrite were studied. The initial ferrite powder and the various reduction products were characterized by X-ray diffraction, scanning electron microscopy, reflected light microscope and vibrating sample magnetometer to reveal the effect of hydrogen reduction on the composition, microstructure and magnetic properties of the produced Fe-Ni-Co alloy. The arrhenius equation with the approved mathematical formulations for the gas solid reaction was applied to calculate the activation energy($E_a$) and detect the controlling reaction mechanisms. In the initial stage of hydrogen reduction, the reduction rate was controlled by the gas diffusion and the interfacial chemical reaction. However, in later stages, the rate was controlled by the interfacial chemical reaction. The nature of the hydrogen reduction and the magnetic property changes for nickel cobalt ferrite were compared with the previous result for nickel ferrite. The microstructural development of the synthesized Fe-Ni-Co alloy with an increase in the reduction temperature improved its soft magnetic properties by increasing the saturation magnetization($M_s$) and by decreasing the coercivity($H_c$). The Fe-Ni-Co alloy showed higher saturation magnetization compared to Fe-Ni alloy.