• Journal of Information Technology Services
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• v.14 no.4
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• pp.137-157
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• 2015

The development of Social Network Service (SNS) has brought many positive changes to the ways people communicate, interact and share information. However, using the SNS does not always leads to in a positive results, particularly when it is addictively used. In fact, the addictive use of SNS results in many negative effects in our society. Recently, SNS users feel negative emotions such as expecially stress and fatigue while using SNS. Thus, the purpose of this study is to empirically examine antecedents of user fatigue on SNS, which can be explained by the degree of Individual, environment and SNS characteristics. This study also examines consequences of user fatigue on SNS. Lastly, we examine the moderating effects of Habit among SNS fatigue, barrier of living and task performance decline. The data for empirical analysis were collected 401 responses on SNS users in Korea. The results of this study are as follows; First, reputation perception, loneliness, unwanted relation, privacy concern, information overload, social presence and interaction are significantly related to SNS fatigue. Second, SNS fatigue, barrier of living and Task performance decline are significantly related to discontinuous usage intention. Third, the moderating effect of Habit of SNS using is found in the relationship among SNS fatigue, barrier of living and task performance decline. Based on the results of this study, Theoretical and practical suggestions were discussed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.2
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• pp.191-198
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• 2010

The noise by the construction activities is one of the main issues in Korea. To prevent the noise from construction site, construction company installs temporary noise barriers along the construction site boundary. Normally sound insulation performance ($R_w$) of the temporary noise barriers made by metal or plastic is between 18 and 31 dB and metallic noise barriers are around 5 dB higher than plastic noise barriers. Sound absorption performance (NRC) of the temporary noise barriers are between 0.20 and 0.59 so it's difficult to characterize their acoustic performance. In this study, it has founded that sound insulation performance of the temporary noise barrier has been improved about 3dB by stick the high density acoustic sheet and insertion loss of noise barrier is getting increased as the source and receiver approached the temporary noise barriers.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.94-100
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• 2008

Noise barriers are being used more often to solve problems of noise pollution from traffic noise. Several types of noise barriers are being installed to increase the cost-effectiveness of noise barrier installation. In this study, the insertion loss is analyzed to evaluate the effectiveness of the noise barrier by using the BEM. In order to check the validity of the BEM, the BEM and Lam's theoretical analysis are compared with measurement, which is performed in the anechoic chamber for the 1/10 scale-down model, and good agreements are obtained. By using the two dimensional boundary element method, the insertion loss is calculated and analyzed for several typical noise barriers such as the vertical barrier, the barrier with an oblique edge on top, the T-shaped barrier and the barrier with interference device on top. With these analyses, it is possible to design more cost-effective noise barriers appropriate for a particular area.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.124-134
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• 2016

Research on low height noise barriers installed adjacent to railways to reduce the height of the noise barrier has actively progressed in many countries except Korea. The performance of low height noise barriers is evaluated to identify barrier acoustic characteristics using a scale model of the barrier in the present research. As shown in the experimental results, if it is considered the installation of 'ㄱ' type noise barrier, sound absorption material should be installed on both the top and the vertical surfaces of the barrier to improve insertion loss. Also, an analytical method such as the boundary element method, rather than a simple empirical equation, is required to evaluate the insertion loss of the barrier. In addition, noise level increase in passenger position is very small if a barrier with sound absorption material is installed. Finally, the two dimensional boundary element method is implemented to predict the acoustic characteristics of the low height barrier; the possibility of the application is confirmed from a comparison of the results of measurements and predictions.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.897_898
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• 2009

This paper deal with the shape design of the flux barrier to maximize the torque density and minimize the torque ripple in IPM type BLDC motor. The variation of magnetic torque and reluctance toque according to the flux barriers is analyzed in the 120 conducting period. From the result, we confirmed the barrier can be quite worthwhile for the better performance of IPM type BLDC motor

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.910-913
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• 2003

In order to enhance performance, stability, and brightness of inorganic blue-light emitting EL device, barrier layer structure and pulsed laser annealing(PLA) treatment were introduced. The barrier layer structure was utilized for improving brightness of the device and instead of thermal annealing, pulsed laser annealing process was used. From this study, optimum barrier layer thickness and number of pulsed laser irradiation are established.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2076-2081
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• 2008

In this study, a new concept of a flow sensor is developed using dielectric barrier discharge (DBD). Current of DBD generated between two electrodes is changed with varying flow rates. Therefore, it is possible to measure the flow rate by correlating generated DBD current with flow rates. The effects of flow rate, frequency, channel height, diameter of electrodes and distance between electrodes on the performance of the flow sensor using DBD are experimentally investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.749-754
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• 2002

This paper investigates the insertion loss of nosie barrier with a interference device. The efficiency of the conventional interference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the nosie barrier in the range of broadband frequency, by changing the shape of interference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• Elastomers and Composites
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• v.54 no.3
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• pp.175-181
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• 2019

The research and development of high-performance polymer materials with excellent gas barrier properties has gained considerable attention from the viewpoint of expanding their applications in various fields, including tire automobile parts and the polymer film industry. Natural rubber (NR) has been widely used as a rubber material in real-life, but its application is limited owing to its poor gas barrier properties. In this paper, we study the gas barrier properties of NR, epoxidized natural rubber (ENR), and their blend compositions by using molecular simulation. The results show that ENR-50 has superior oxygen barrier properties than those of NR. Moreover, the oxygen barrier properties of a blend of NR/ENR-50 improve with increasing volume fraction of ENR-50. The trend of improved oxygen barrier properties of NR, ENR-50, and their blend is in good agreement with experimental observations.

• Fire Science and Engineering
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• v.18 no.4
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• pp.93-102
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• 2004

The function of fire barrier penetration sealing is highly important to confine a fire propagation a fire severity within a fire area where the fire started. Especially for the penetration seals at the nuclear power plants with the long-term operated history, it is needed to make it clear that the conformance to the sealing requirements has been proven to guarantee the fire-resistive performance of fire barrier penetration parts. If there are any parts of fire barrier penetration sealing which can not meet the required rating for the fire endurance performance, the relevant parts must be modified to meet regulatory requirements. At this paper, the engineering analysis methodology was established to approximate the fire endurance rating for the fire barrier penetration seals. With this study, the method of engineering analysis to decide fire endurance rating for the fire barrier penetration seals was established and this way can be utilized to check the performance of the fire rating for the penetration seal at the domestic nuclear power plants.