• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.116-125
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• 2011

This study examined vertical shafts in high-rise apartments of the old high-rise buildings, reviewed the possibility of using flue ducts, and analyzed airflow patterns according to pressure differences between in and out side of flue ducts through computational fluid dynamics(CFD). The resulting conclusions are as follows: 1) The analysis results of airflow according to the stack effect of flue ducts show that smaller-diameter flue ducts(${\phi}1.2m$) would be morefavorable in increasing downward wind velocity than bigger-diameter ones(${\phi}1.6m$) and that the introduction ducts for outside air should be more than 50% of flue duct diameter to obtain a downward wind velocity higher than $3.0^m/s$ that is the minimum blade wind velocity of a small domestic wind generator. 2) The optimal installation location of a bypass introduction duct is the neutral plane of a flue duct or lower. When the diameter of the upper duct is bigger than that of the lower duct, it will generate more effects on the increase of downward wind velocity in flue ducts.

• Korean Journal of Veterinary Research
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• v.58 no.2
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• pp.73-79
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• 2018

Outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated sow herds from occurrence to stabilization were monitored and analyzed in terms of serology and reproductive performance. Three different conventional pig farms experienced severe reproductive failures with the introduction of a type 1 PRRSV. These farms had adopted mass vaccination of sows using a type 2 PRRSV modified live vaccine (MLV). Therefore, to control the type 1 PRRSV, an alternative vaccination program utilizing both type 1 and type 2 MLV was undertaken. Following whole herd vaccinations with both types of MLV, successful stabilization of PRRS outbreaks was identified based on serological data (no viremia and downward trends in ELISA antibody titers in both sows and suckling piglets) and recovery of reproductive performance. Additionally, through comparison of the reproductive parameters between outbreak and non-outbreak periods, it was identified that PRRSV significantly affected the farrowing rate and the number of suckling piglets per litter at all three pig farms. Comparison of reproductive parameters between periods when the different vaccination strategies were applied revealed that the number of piglets born in total and born dead per litter were significantly increased after the introduction of the type 1 PRRS MLV.

• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.74-87
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• 2001

When the revegetation of the slopes is required, it is more desirable to consider it from the ecological view point rather than from the disaster-preventive one because the environment is critical for the introduction of pioneer plants to the denuded slopes. The ecological point of view adheres to the maintenance of the present, original ecosystem of the construction area. The new revegetation technology is presented using native microorganisms and its effective usuage was discussed based on the data in the research field. Direct seeding is recommended and explained in detail than planting seedlings. The importance of inclination angle of slope face is shown for the successful revegetation from its relationship with the thickness of soil. It is indicated that the introduction of pilot plants to the slopes should include their ability to ease the acid rain effects as much as possible. Finally every construction may not be desirable for the maintenance and improvement of the global ecosystem without the consideration of the opinions mentioned above.

• Journal of Information Technology Applications and Management
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• v.16 no.4
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• pp.205-222
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• 2009

Considering time-lag in the performance evaluation of information system (IS) investment is important because its effect reveals after certain period of time passed. Particularly it is more in the systems of e-government informatization projects which the amount of investment and the scale of business are huge. Many methods to solve this issue have been proposed such as system dynamics methods, simulations, structural equations etc. However, it is still difficult and unsolved problem because collecting practical data for time-lag analysis is very hard. In this paper, we analyze IS time-lag effect through factor analysis using the accumulated practical operational DB data. For the performance evaluation of the G4C system, the representative e-government web portal, we selected eleven factors reflecting time passing in G4C DB data. With these factors this paper conduct time-lag analysis in four view points. First, we conducted 'Stabilizing of G4C system' and got a result that IS is needed about three years for the stabilization. Second, we conducted 'Utilization of G4C system' and got a result that the utilization reaches appropriate level after in three years later after the introduction of G4C system. Third, we conducted 'Cost reduction effect' and got a result that cost reduction is stable in the third year after the introduction of G4C system. Lastly, we conducted 'System maturity effect' and got a result that the system reaches to the quality level that users expect after third to fourth years. According to the results of this research, we found that performance of IS improv continuously not immediately, and it needs three or four years of time-lag.

• Journal of Forest and Environmental Science
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• v.22 no.1
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• pp.41-49
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• 2006

The design instruction put in the wood structure construction manual of forest engineering works issued in Japan in 2004 is composed of the introduction, the use and characteristic of wood, investigation, planning, design, and etc. of wood structures. We analyzed the introduction, the use and characteristic of wood, investigation and planning for wood structures. By the results. the contents on the characteristic of wood are shown about physical and chemical properties of wood, the environmental influence, psychological and physiological effects, and rot of wood. The investigation items include the effective degree by flow and insolation, white ant's genital existence, flow conditions of surface water and ground water, situations of flora and fauna to live in mountain stream, the condition of water use, and etc. Also, the contents for the planning are explained for the structure, installation features. treatments, use of wood and lumber in the regions, preservative treatment, and etc.

• Research in Community and Public Health Nursing
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• v.26 no.3
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• pp.278-291
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• 2015

Purpose: This study was conducted to examine differences in health care utilization and related costs between before and after the introduction of the designated doctor system, and to find out factors making the differences. Methods: Data were collected from 200 medical aid beneficiaries having one or more chronic diseases, registered in the designated doctor system during the year of 2012, and the relationship between the use of health services and claimed medical expenses was analyzed through paired t-test and multiple regression analysis using the SPSS 18.0 program. Results: There was a decrease in the number of total benefit days and the number of outpatient and medication days, but some cases showed an increase after the designation of medical institution. In general, hospital stay increased after the introduction of the system. However, the number of medical institutions utilized was reduced in most cases after designation. Conversely, medical expenses increased in most cases after the designation of medical institution. Conclusion: These results suggest that a detailed scheme to designate medical institutions should be made in consideration of the seriousness of illness and classification of medical institutions not only for the beneficiaries' enhanced health but for the effective management of medical aid fund.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.286-296
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• 2018

Maintenance of a beneficial microbial community, especially in the rhizosphere, is indispensable for plant growth and agricultural sustainability. In this sense, plant growth-promoting rhizobacteria (PGPR) have been extensively studied for their role in plant growth promotion and disease resistance. However, the impact of introducing PGPR strains into rhizosphere microbial communities is still underexplored. We previously found that the Proteus vulgaris JBLS202 strain (JBLS202) promoted growth of Kimchi cabbage and altered the relative abundance of total bacteria and Pseudomonas spp. in the treated rhizosphere. To extend these findings, we used pyrosequencing to analyze the changes in bacterial communities in the rhizosphere of Kimchi cabbage after introduction of JBLS202. The alterations were also evaluated by taxon-specific realtime PCR (qPCR). The pyrosequencing data revealed an increase in total bacteria abundance, including specific groups such as Proteobacteria, Acidobacteria, and Actinobacteria, in the treated rhizosphere. Time-course qPCR analysis confirmed the increase in the abundance of Acidobacteria, Actinobacteria, Alphaproteobacteria, and Betaproteobacteria. Furthermore, genes involved in nitrogen cycling were upregulated by JBLS202 treatment indicating changes in ecological function of the rhizosphere soil. Overall, these results indicate that introduction of JBLS202 alters both the composition and function of the rhizosphere bacterial community, which can have direct and indirect effects on plant growth. Therefore, we propose that long-term changes in bacterial composition and community-level function need to be considered for practical use of PGPRs.

• The Journal of the Korean dental association
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• v.52 no.12
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• pp.783-794
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• 2014

Since the introduction of non-thermal atmospheric pressure plasma in the field of the dentistry, numerous applications have been investigated. Especially with its advantages over existing vacuum plasma in terms of portability, low cost, and non-thermal damage, it can be directly applied in the oral cavity, giving number of potentials for dental application. First, possible application of non-thermal atmospheric pressure plasma in the field of dentistry is relation to dental caries and periodontal diseases. Teeth and alveolar bones are one of the strongest bony structures in our body, but it cannot be regenerated when they are damaged by dental caries or periodontal disease. Hence many studies to prevent such diseases have been carried out, though no perfect solution has been found yet. With recent studies of modifying surfaces through non-thermal atmospheric pressure application that can prevent attachment of bacteria, or studies on bactericidal effects of non-thermal atmospheric pressure plasma can be applied here to prevent oral pathogen and 'biofilm' attachment to the surface of teeth or directly eliminate the dental caries/periodontal disease causing germs. Secondly, non-thermal atmospheric pressure application will be useful on the surface of dental implant. It is well known that the success of dental implant surgery depends on the process known as 'osseointegration' that result from osteoblast attachment, proliferation and differentiation. As the application of non-thermal atmospheric pressure plasma on the surface of dental implant just before its introduction by the chair-side of dental surgery. Despite its long history, the generation of non-thermal atmospheric pressure plasma has been greatly increased with its application in dentistry.

• Journal of Navigation and Port Research
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• v.34 no.3
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• pp.221-228
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• 2010

As container traffic is increasing, the introduction of mega-vessel has had a significant impact on the ports and terminals business. This movement of container shipping has led to intensely competitive environment among ports, so substantial pressures to develop new container ports or to expand existing ones, have been grown. However, it requires a huge investment, especially cost and time, to overcome environmental, geographical and financial restrictions generated from developing a port. This study addressed the Mobile Harbor, the new concept of marine logistics system as an alternative strategy. We performed an economic analysis on the introduction of the Mobile Harbor in coastal transport sector and also a sensitivity analysis to examine the effects of changing factors related on the economic evaluation. We have examined the value and application of Mobile Harbor as a preliminary study, which may contribute to further studies on the Mobile Harbor.

• The Korean Journal of Soil Zoology
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• v.2 no.2
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• pp.83-91
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• 1997

One year study with litter bags(mesh size - 0.4mm, 0.8mm, 1.7mm and 5.0mm) was carried out to investigate the soil invertebrate community in the process of leaf decomposition in Namsan and Kwangreung deciduous forests, which were considered to be under different degrees of environmental selective pressure. Soil animals collected from litter bags were classified into the class of order or higher taxa. Acari and Collembola were major groups: Acari and Collembola were about 60% and 30% of total soil animals in their numbers, respectively. Among minor groups, Dipteria, Araneae, Diplopoda, Coleoptera and Chilopoda were comparatively dominant. In Namsan forest which was considered to be under higher environmental selective pressure than Kwangreung, the densities of Acari and Collembola were somewhat higher than in Kwangreung, although there was no statistically significant difference between two sites. The densities of Chilopoda, Enchytraeidae and Nematoda were much higher in Namsan than in Kwangreung but Diplopoda and Symphyla were much more in Kwangreung. It was expected that those groups could be used as bioindicators. The densities of Acari and Collembola were very low until March and then showed the peak in May. But they decreased slowly until November. There was no significant difference among the mesh sized of litter bags in the densities of Acari and Collembola but other groups of soil invertebrates seemed to be prevented from immigrating into the litter bag of mesh size 0.4mm. Decomposition rate of litter in the litter bag was low in early stage of decomposition. The % residual mass over initial mass at 8 months after litter bag introduction in the field was over 80%. Thereafter, % residual mass decreased more fast and was about 60% at 1 year after bag introduction. There was little evidence for the effects of soil invertebrates upon the litter decomposition in the period of this study. And there was no significant difference between Namsan and Kwangreung or among mesh sizes of litter bags in the decomposition rate.