• The Journal of Society for e-Business Studies
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• v.14 no.4
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• pp.95-118
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• 2009

Virtual community, which is formed on the internet, is expected to serve the needs of members for communication, information, and knowledge sharing. The executives of organizations should consider operating strategy of virtual community as a new innovation or knowledge pool since members share knowledge. However, many virtual community have failed due to members' low willingness to engage and furthermore to share knowledge with other members. Thus, there is a need to understand and foster the determinants of members' loyalty in virtual community. The objective of this study is to develop an integrated model designed to investigate and explain the relationships between contextual factors, personal perceptions of virtual community, usefulness, ease of use, familiarity, members' trust, reputation, community trust, attitude, satisfaction and loyalty. Empirical data was collected from 286 internet users and tested using structural equation modeling to verify the fit of the hypothetical model. The results show that the usefulness, familiarity significantly influences attitude and members' trust is significantly influence the community trust. And I confirmed that ease of use and attitude play the role of determinants in making the satisfaction, community trust and reputation influence the satisfaction that have the direct effect to making the loyalty. The results of the study can be used to identify the loyalty in virtual community. By investigating the impacts of contextual factors and personal perceptions on virtual community, the integrated model better explains behavior than other proposed models. This study might help executives of virtual communities and organizations to manage and promote community trust, attitude, satisfaction to stimulate members' willingness to revisit the community and futhermore enhance their virtual community loyalty.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.24-33
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• 2000

Switching behaviour of the ferroelectric thin film and device characteristics of the MFSFET(Metal-Ferroelectric-Semiconductor FET) are simulated with taking into account the accumulation of oxygen vacancies near interface between the ferroelectric thin film and the bottom electrode caused by the progress of fatigue. In our switching model, relative switched charge is 0.74 nC before fatigue, but after the progress of fatigue it reduces to 0.15 nC with the generation of oxygen vacancies. It indicates that the generation of oxygen vacancies strongly suppresses polarization reversal. $C-V_G\;and\;I_D-V_G$ curves in our MFSFET device model exhibit the memory window of 2 V and show the accumulation, the depletion and the inversion regions in capacitance characteristic clearly. The difference of saturation drain current of the device before fatigue in shown by the dual threshold voltages in $I_D-V_G$ curve as 6nA/$cm^2$ and decreases as much as 50% after fatigue. Decrease of the difference of saturation drain currents by fatigue implies that the accumulation of oxygen vacancies with the fatigue should be avoided in the device application. Our simulation model is expected to play an important role in estimation of the behavior of MFSFET device with various ferroelectric thin films.

• Journal of Korea Port Economic Association
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• v.33 no.1
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• pp.47-59
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• 2017

The objective of this study is to determine the short run and long run dynamics between maritime import volume (IMV), industrial production (IP), and real effective exchange rate (REER) of the Korean Won over the REER of certain major currencies (US Dollar, Chinese Yuan, and Japanese Yen) in Korea's Jeonnam province. The Johansen and Juselius cointegration results reveal that at least one cointegration vector or long-run relationship exists. Hence, this study estimated the long run equilibrium equation, which indicates that both IP and REER are inelastic, although the former is bigger than the latter. Moreover, the dynamic causality analysis reveals short and long-run unidirectional causality from IP and REER to IMV in all three models. Further, in all the models, the results indicate short run unidirectional causality from REER to IP. In addition, the impulse response (IR) results show that the impulse of IP and REER decayed after four months. Additionally, the IR analysis results indicate that the REER of the Korean Won over the REER of Japanese Yen is the biggest with respect to the impact of relative REER on IP, which is the proxy variable of regional real income. Thus, empirical results indicated that real income and REER play an important role in determining the Jeonnam's maritime import demand behavior in the short run and long run. More importantly, substantial actions reducing unexpected fluctuation of the REER and real income based on micro and macro economic policies will increase the imported volume in the ports of the Jeonnam province.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.375-380
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• 2006

A solitary endoparasitoid, Cotesia plutellae, parasitizes diamondback moth, Plutellae xylostella. It has been suggested that its antennae are a major sensory organ to search host and recognize host developmental and other physiological condition during parasitization. This research was performed to understand the parasitic behavior of C. plutellae by analyzing sensory types and their numbers on the antennae using scanning electron microscope. There was no significant difference in antennal length in both male and female C. plutellae, in which both sexes had 16 flagellomeres. Three different types of sensilla (trichoid, seta, and placodea sensilla) were located mostly on flagella and analyzed in their density on the different antennomeres. Trichoid sensillum was the major sensory type and showed about 87% density among all sensilla. Both trichoid and placodea types of sensilla exhibited even numbers on all flagellomeres with some decrease at terminal segments. In contrast, seta form of sensilla showed drastic increase in its density at distal part after 9th flagellomere. When distal half of flagellomeres were cut off, the C. plutellae could not parasitize host larvae. Even when only four distal flagellomeres were removed, the parasitism showed only 30%. These results indicate that C. plutellae antennae are required for parasitism and suggest that seta form of sensilla may play significant roles in recognizing host for parasitization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.3
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• pp.75-84
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• 1991

When we construct the earth structures such as embankments, on soft ground which are consisted of thick marine silty clay, the foundations deform due to consolidation and creep. For the stabilization of the earth structures constructed on soft foundations, we usually uses the mattress and they play an important role in increasing an ultimate bearing capacity by the dispersion of load of embankment. The purpose of this paper was to predict rationally a long term deformation of earth structures and to contribute to embankment design and maintenance. We determined a rheological model of marine clay from experimental data, and developed a computer program using the chosen model and found out the long term behavior of embankment. The results of this paper are as follows: 1. The developed program can analyze simultaneously consolidation and creep. 2. From the results of creep test, the rheological model of marine silty clay can be represented by the Vyalov model. 3. The displacement of embankment on reinforced foundation were smaller than those of the unreinforced foundation in showing the effects of geotextiles on foundation deformations.

• Journal of Music and Human Behavior
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• v.13 no.1
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• pp.19-40
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• 2016

This study provides numerical data on the status of music therapy practices in 54 hospice and palliative care settings in Korea. Two different questionnaires for music therapists and coordinators were sent to 54 coordinators via email, and 47 (87%) hospitals and centers replied by email or post. The survey period was October 30 through December 5, 2014. Music therapists were asked to respond to 65 questionnaire items regarding working conditions, environment, session process, and personal competence. Coordinators were asked to complete 28 questionnaire items regarding the status of music therapy in their perspective setting. Twenty-two (46.8%) hospitals and centers were running music therapy programs with 28 music therapists, and 19 (67.9%) of these music therapists majored in music therapy. There was a significant difference between music therapists (M= 3.43, SD = 0.96) and coordinators (M= 2.73, SD = 0.77) regarding conditions and environment of music therapy sessions (p < .05). The circumstances and conditions for music therapy are inad quate for optimal implementation of music therapy practice. However, the perceived benefits of music therapy by coordinators suggest that music therapists do play an important role in hospice and palliative care. This research provides the first quantitative baseline data of music therapy status in hospice and palliative care settings in Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.324-333
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• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.653-657
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• 2009

Nitrous oxide is a typical greenhouse gas which is produced from various organic or fossil fuel combustion processes as well as chemicals producing plants. $N_2O$ has a global worming potential of 310 times that of $CO_2$ on per molecule basis, and also acts as an ozone depleting material in the stratosphere. However, its removal is not easy for its chemical stability characteristics. Most SCR processes with several effective reducing agents generally require the operation temperature higher than $450^{\circ}C$, and the catalytic conversion becomes decreased significantly when NOx is present in the stream. Present experiments have been performed to obtain basic design data of actual application concerning the effects of $SO_2$ and $NH_3$ on the interim and long term activities of $N_2O$ reduction with CO over the mixed metal oxide (MMO) catalyst derived from a hydrotalcite-like compound precursor. The MMO catalysts used in the experiments, have shown prominent activities displaying full conversions of $N_2O$ near $200^{\circ}C$ when CO is introduced. The presence of $SO_2$ is considered to show no critical behavior as can be met in the $NH_3$ SCR DeNOx systems and the effect of $NH_3$ is considered to play as mere an impurity to share the active sites of the catalysts.

• The Korean Society of Law and Medicine
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• v.12 no.1
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• pp.133-173
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• 2011

Since mid-1960s the reports from the Surgeon General, the World Health Organization, and other health experts state that there is no risk-free level exposure to smoking and secondhand smoke. Tobacco smoke is made up of more than 7,000 chemicals. Hundreds are toxic, and at least 70 are carcinogens. The chemicals in tobacco smoke reach smoker's lungs quickly every time smoker inhale causing damages immediately. Inhaling even the smallest amount of tobacco smoke can also damage smoker's DNA, which can lead to cancers. Smoking is responsible for more than 87% of lung cancers, but there are a host of other chronic diseases directly related to exposure to tobacco smoke. It's also a major cause of heart disease, stroke, aortic aneurysm, peripheral arterial disease and most of the other diseases. In the United States, each year with more than from 440,000 to 520,000 deaths caused by smoking and exposure to involuntary smoke. They conclude that smoking is the single most important source of preventable morbidity and mortality. The United States of America have about 60-year history of tobacco litigation. Tobacco litigation has been an important tool in tobacco control strategies aimed at limiting the activities of tobacco companies and providing redress to people who have become ill as a result of their use of tobacco products. Tobacco litigation is a kind of tort litigation. Quite often, as in the asbestos and other mass tort litigation episodes, tobacco litigation can play an educational role, warning the public about the magnitude of health risks that might otherwise be less clearly perceived. Tobacco litigation allows smokers, their families or other victims of smoking to sue tobacco companies in order to be compensated for the harm they have suffered. Potential benefits of tobacco litigation include compensation for smoking-related damages, strengthening regulatory activity, publicity, documents disclosure and changing tobacco industry behavior. And also tobacco litigation can limit the political activities of tobacco industry, protect human rights of smokers and non-smokers, increase burden to tobacco price-up and enhance the effects of law and politics in public health.

• Applied Microscopy
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• v.33 no.2
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• pp.105-116
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• 2003

In Vitro fertilization of U. unicinctus eggs observed by immunofluorescence and electron microscopes revealed an overview of the meiotic pattern of the tide animals. The eggs have been fertilized early at germinal vesicle stage, followed by germinal vesicle break down (GVBD), but pre-mitotic aster like structure could not be resolved by the methods employed in this work. The meiotic features, such as rotation-shift movement of spindle fibers, behavior of spermatozoonmonaster in the egg cytoplasm and active spindle fiber of the 1st polar body, have been observed. The antitubulin-FITC fluorescence show the 2nd meiotic apparatus appeared firstly parallel to the tangential line of the oolemma, proceeding the meiosis, its bipolarity is rotated and shifted towards the oolemma. The polar bodysite of the oolemma was not amorphous, but active in a sense of anti-tubulin-FITC reactions during the extrusions of the polar bodies. The immunofluorescence reactions of the spermatozoon centriole appeared at a later stage of the 2nd meiosis. During the time periods, the fertilized spermatozoon resided in the egg cytoplasm. Activating the centrioles, spermatozoon approaches towards the chromosomal materials of the 2nd oocyte. This suggests that spermatozoon centrioles initiate and play a roll to fuse male and female pronuclei.