• Convergence Security Journal
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• v.8 no.3
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• pp.73-81
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• 2008

We can find easily about researches or technical development that deal with grasping the location of an object with GPS(Global Positioning System) in order to use them as a useful information. Most researches or technical development on application of tracing have been developed for the purpose of tracing objects in broad area as physical distribution or transportation, but recently, there are many researches on tracing materials in premise area as a fork lift, carts, or the equipment of work. In general, a system that utilizes location information of objects needs data communication network to transmit location data and it ensures data communication network by using common networks(SK, LG, KFT) or wireless LAN. However these two methods need monthly payment for the rental fee or require considerable amount of investment for the early stage so it is difficult to use them merely for tracing premise subjects. This study was conducted to build a tracing system for premise area by local area RF relay algorithm with low cost applying RF relay algorithm to local area wireless communication(ZIGBEE, 424MHz, Bluetooth, 900MHz) system in order to supplement these demerits and included relay algorithm, RF locating information terminal, local area RF gab-fillers, a plan for collection server of locating information, and the way of realization as they are needed in this system. I consider that this study would be applicable with flexibility in the industry area that needs tracing solution within a specific area or needs ensuring data communication network, to transmit data in ubiquitous environment, by easier and more rapid way with lower cost.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.929-941
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• 2012

In recent years, interest in river environment such as riparian landscape, water quality and ecological conservation has been growing with increasing recreation on agricultural river watershed. That caused the increase of necessity of water resources development, one of solutions for the diversification of agricultural water demand and shortages. In this respects, heightening irrigation dam, as a part of the 4-major river restoration project, is necessary to secure not only additional agricultural water but also instream flow for water quality improvement. However, operation plan of irrigation dam still not be clear. In this study, additional storage which secured through heightening irrigation dam was estimated using SWAT model. And instream flow effects on water quality of downstream were evaluated. The findings show that the additional water supply will contribute positively to water quantity and quality of downstream. The results show a 2~10% water quality improvement effect on nutrients, as well as an 1~8% water quantity increasing effect. In particular, additional storage can be effectively supplied from February to April by the reservoir operation. However, maintaining better water quality in irrigation reservoirs is important because the water quality of irrigation reservoirs can be negatively impacts the water quality in downstream of reservoirs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.253-259
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• 2012

Wastewater-adapted microalgae such as Chlorella vulgaris AG10032, Ankistrodesmus gracilis SAG278-2 and Scenedesmus quadricauda AG10308 are useful biological resources for recovering biofuel and other bio-based materials from wastewater because of their efficient removals of nitrogen and phosphorus from wastewater and their high fatty acid contents in biomass. Although the concentrations of phosphorus typically vary in wastewater environment, very little is known about the effect of phosphorus concentration, especially phosphorus starvation, on microalgal fatty acid synthesis. This is partially due to the lack of methodological establishment for algal fatty acid analysis. In this study, we compared the analysis performances of microalgal fatty acids by two different methods; one is a non-polar GC (gas chromatography) column based method, which is generally used for microbial fatty acids, and the other is a polar WAX-type GC column method, which is typically used for plant fatty acids. And then, we explored the effect of phosphorus concentration levels on fatty acid production in microalgae cultivated from wastewater. As results, the polar WAX-type column method has better ability to separate poly unsaturated fatty acids (PUFA) including $C_{18:3}$ (linolenic acid), and was found to be more applicable in analyzing fatty acids from wastewater-cultivated microalgae than the non-polar column method. The fatty acid characterization by the WAX-type column method revealed little effect of phosphorus starvation on the quantity and composition of fatty acids from wastewater-cultivated microalgae.

• Korean Journal of Childcare and Education
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• v.7 no.4
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• pp.301-324
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• 2011

The purpose of this study was to examine the perception of the childcare teachers regarding accreditation procedures and feasibility of the second accreditation index according their past participation in the accreditation process. The objects were 193 childcare teachers working at child care centers that were accredited using the initial accreditation index. The collected data was analyzed using frequency, percentile, $X^2$, and t-test. The major findings are as follows: First, childcare teachers without accreditation experience perceived 'continuing education of child care center directors and teachers' to be the most important for quality maintenance after successful accreditation. In contrast, childcare teachers with accreditation experience placed the most importance on 'childcare teachers' motivation and continuing enrollment'. Second, childcare teachers with accreditation experience perceived higher feasibility in the subcategories of 'art activity materials' in the category of child care environment, 'providing operation policies and information of child care teachers', 'care for children', and 'employment contract' in the operation & management category, 'sanitary management of food, cooking and feeding', 'care of sick or injured child', 'health management of children and childcare teachers', 'snacks for children' in the category of health and nutrition and 'safe procedures for handing over children' in the category of safety. In general, childcare teachers with accreditation experience perceived higher feasibility of the second accreditation index in all categories.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.203-215
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• 2015

The study aims to identify the degree and types of spatial recessions in Si/Gun and Eup/Myun units within Chungcheong region in South Korea to contribute to the efforts being made to diagnose the rural recession and the potentials. To this end, we analyzed 27 Sis and Guns to identify the degree of recession and potentials of rural areas in Chungcheong region. We also carried out the diagnosis and K-Means Clustering on 274 Eups and Myuns, smaller administrative units, to figure out the types and characteristics of the rural recessions. In case of the analysis targeting the Sis and Guns, a relatively high degree of rural recession was found in Cheongyang, Seocheon and Taean for Chungcheongnam-do, and in Danyang and Goisan, as well as in Boeun, Okcheon and Youngdong - which are collectively called as 'Southern 3 Areas in Chungcheongbuk-do' as they are conventionally known by their high degree of rural recession. According to the results of the clustering analysis carried out on the 166 Eups and Myuns, there were five outstanding clusters. They were; areas with housing deterioration (29), areas with poor economic foundation (16), areas with poor accessibility to central areas (42), areas with poor residential environment (51) and areas with aged population (28). The findings and results of the present study are likely to serve as a basis for the design and enforcement of forthcoming rural area activation policies. Also, it would be highly recommended that a more comprehensive diagnosis is taken from a community-level perspective and policy suggestions and strategies tailored for rural communities are further discussed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.436-445
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• 2014

Objectives: Time-activity studies have become an integral part of comprehensive exposure assessment and personal exposure modeling. The aims of this study were to estimate exposure levels to nitrogen dioxide($NO_2$) and volatile organic compounds(VOCs), and to compare estimated exposures by using time-activity patterns and indoor air concentrations. Methods: The major microenvironments for office workers were selected using the Time-Use Survey conducted by the National Statistical Office in Korea in 2009. A total of 9,194 and 6,130 workers were recruited for weekdays and weekends, respectively, from the Time-Use Survey. It appears that workers were spending about 50% of their time in the house and about 30% of their time in other indoor areas during the weekdays. In addition, we analyzed the time-activity patterns of 20 office workers and indoor air concentrations in Daegu using a questionnaire and time-activity diary. Estimated exposures were compared with measured concentrations using the time-weighted average analysis of air pollutants. Conclusions: According to the time-activity pattern for the office workers, time spent in the residence indoors during the summer and winter have been shown as $11.12{\pm}2.20$ hours and $12.48{\pm}1.77$ hours, respectively, which indicates higher hours in the winter. Time spent in the office in the summer has been shown to be 1.5 hours higher than in the winter. The target pollutants demonstrate a positive correlation ($R^2=0.076{\sim}0.553$)in the personal exposure results derived from direct measurement and estimated personal exposure concentrations by applying the time activity pattern, as well as measured concentration of the partial environment to the TWA model. However, these correlations were not statistically significant. This may be explained by the difference being caused by other indoor environments, such as a bar, cafe, or diner.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.536-546
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• 2014

Objectives: The major objective of this paper is compare the exposure work hours and experieence of ill health symptoms among under and over employment and matched group. Workers with over employment have more exposed to hazards than that with under employment because that workers with over employment work more than those with ender employment. Methods: This study as heuristics one used the third Korean Working Conditions Survey done by Occupational Safety and Health Research Institute in 2011. The sample size is 50,023 economic active persons. Over and under employment were measured by matching method of preferred and actual work hours. The exposed work hours to hazards were measured according to 13 hazardous factors and the experience of ill health symptoms were scaled by the number of experienced 14 ill health symptoms. To compare the exposure and the symptoms experience were compared by mean difference test with F test. Results: The proportion of over employment in male employees is 32.1% and that in female employees is 29.3% and under employment rate is 11.2% in mae and 13.9% in female employees. There is significant difference of the rate of over and under emplyment among age groups, industrial sectors, occupational groups and the state of employment. The difference of the exposed work hours to hazards among under, over and matched group were statistically significant in all hazards by gender. The exposed work hours to hazards in over employment were more than those in under employment. The number of experienced symptoms in over employment is statistically significantly more than that in under employment. Conclusions: Workers with over employment may be vulnerable group in the criteria of hazard exposure and health status. The results have some implications and limitations because that this study is heuristic one. The mismatch of preferred and actual working hours may be unfavorable work condition that has impact on safety and health of workers. The impact mechanism may be investigated as future study, Because that this study used cross sectional survey data, some causal relationships cannot be evaluated.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.145-153
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• 2013

High-resolution chirp profiles were analyzed to investigate the echo types of near-surface sediments in the Yellow Sea off the Baegryeong Island. On the basis of seafloor morphology and subbottom echo characters, 7 echo types were identified. Flat seafloor with no internal reflectors or moderately to well-developed subbottom reflectors (echo type 1-1 and 1-2) is mainly distributed in the southern part of the study area. Flat seafloor with superposed wavy bedforms (echo type 1-3) is also distributed in the middle part. Mounded seafloor with either smooth surface or superposed bedforms (echo type 2-1, 2-2, and 2-3) occurs in the middle part of the study area. Irregular and eroded seafloor with no subbottom reflectors (echo type 3-1) is present in the northern part of the study area off the Baegryeong Island. According to the distribution pattern and sedimentary facies of echo types, depositional environments can be divided into three distinctive areas: (1) active erosional zone due to strong tidal currents in the northern part; (2) formation of tidal sand ridges in response to tidal currents associated with sea-level rise distributed in the middle part; and (3) transgressive sand sheets in the southern part. Such a depositional pattern, including 7 echo types, in this area reflects depositional process related to the sea-level rise and strong tidal currents during the Holocene transgression.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.336-342
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• 2013

Trichloroethylene (TCE) is a widely used substance in commercial and industrial applications, yet it must be removed from the contaminated soil and groundwater environment due to its toxic and carcinogenic nature. We investigated bacterial community structure, dominant bacterial strain, and removal efficiency in a TCE contaminated groundwater treatment system using immobilized carrier. The microbial diversity was determined by the nucleotide sequences of 16S rRNA gene library. The major bacterial population of the contaminated groundwater treatment system was belonging to BTEX degradation bacteria. The bacterial community consisted mainly of one genus of Pseudomonas (Pseudomonas putida group). The domination of Pseudomonas putida group may be caused by high concentration of toluene and TCE. Furthermore, we isolated a toluene and TCE degrading bacterium, named Pseudomonas sp. DHC8, from the immobilized carrier in bioreactor which was designed to remove TCE from the contaminated ground water. Based on the results of morphological and physiological characteristics, and 16S rRNA gene sequence analysis, strain DHC8 was identified as a member of Pseudomonas putida group. When TCE (0.83 mg/L) and toluene (60.61 mg/L) were degraded by this strain, removal efficiencies were 72.3% and 100% for 12.5 h, respectively. Toluene removal rate was 2.89 ${\mu}mol/g$-DCW/h and TCE removal rate was 0.02 ${\mu}mol/g$-DCW/h. These findings will be helpful for maintaining maximum TCE removal efficiency of a reactor for bioremediation of TCE.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.347-354
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• 2013

In the recent global construction environment, EPC contracts that integrate planning, design, procurement, and construction have been widely used for industrial facilities. Similarly, as the importance of the engineering capability such as project management consulting(PMC) and front end engineering design(FEED) has been increased, design-build contracts also have been gradually adopted for infrastructure projects. Whereas, the Korean infrastructure industry has fragmentary features which mainly emphasize on the construction sector. Therefore, this study aims at developing strategies for enhancing the engineering capability and for balancing the competitiveness between engineering and construction sectors in the Korean infrastructure industry. To this end, the authors first carried out market analysis for both global and domestic market. Then, a structured survey and expert in-depth interviews were sequentially performed in order to reflect practitioners' perspectives and needs for institutional strategies. As a result, five strategies drawn from this study are as follows: 1) rearranging the government's roles for supporting the engineering sector; 2) establishing institutional bases being compatible with global standards; 3) fostering value-added workforce for undertaking complex tasks; 4) constructing an consortium between an engineering association and general contractors; and 5) building a nationwide collaborative networks for overseas market expansion.