• Applied Biological Chemistry
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• v.43 no.2
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• pp.124-129
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• 2000

Nitrogen and P in surface runoff and eroded sediment from cropland areas can contaminate streams and lakes. Runoff losses of N and P were determined in a small field plot $(14.3{\times}24.8\;m)$ of peach orchard from March to November in 1999. Nitrogen and P were applied in the rate of 172 and 46 kg/ha using chemical fertilizer and mixed oil cake fertilizer. During the season, in 26 rainfall events, $421.5\;m^3/ha$ of runoff including 1,989 kg/ha of soil loss was collected. Concentrations of total-N, $NO_3-N$, $NH_4-N$, total-P and $PO_4-P$ in runoff samples were in the range of $4.7{\sim}171.0,\;0.1{\sim}188.0,\;0.13{\sim}3.36$, $0.58{\sim}4.99$ and $0.05{\sim}3.71\;mg/l$, respectively. Total loss of N was 16.39 kg/ha and 75% of the loss was $NO_3-N$. Total loss of P was 1.04 kg/ha, and $PO_4-P$ and sediment bound P accounted for 47 and 27% of the total loss, respectively. The losses of N and P were about 9.5 and 2.3% of the applied N and P in the plot, respectively. Although the loss of N or P would be relatively small in agricultural aspect, considering the high concentrations of N and P in runoff, loss of N and P from croplands should be controlled to reduce the eutrophication problem of stream waters.

• Journal of Korean Society of Transportation
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• v.23 no.3 s.81
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• pp.125-136
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• 2005

The current traffic accident reduction procedure in economic feasibility study does not consider the characteristics of road and V/C ratio. For solving this problem, this paper suggests methods to be able to evaluate safety of each road in construction and improvement through developing accident Prediction model in reflecting V/C ratio Per road types and traffic characters. In this paper as primary process, model is made by tke object of urban roads. Most of all, factor effecting on accident relying on road types is selected. At this point, selecting criteria chooses data obtained from road planning procedure, traffic volume, existence or non-existence of median barrier, and the number of crossing point, of connecting road. and of traffic signals. As a result of analyzing between each factor and accident. all appear to have relatives at a significant level of statistics. In this research, models are classified as 4-categorized classes according to roads and V/C ratio and each of models draws accident predicting model through Poisson regression along with verifying real situation data. The results of verifying models come out relatively satisfactory estimation against real traffic data. In this paper, traffic accident prediction is possible caused by road's physical characters by developing accident predicting model per road types resulted in V/C ratio and this result is inferred to be used on predicting accident cost when road construction and improvement are performed. Because data using this paper are limited in only province of Jeollabuk-Do, this paper has a limitation of revealing standards of all regions (nation).

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.116-124
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• 2010

While groundwater is the major source for drinking and irrigation purposes, arsenic (As) contamination of groundwater is a serious issue in Bangladesh. With a view to reduce As contamination in drinking water the guideline value recommended for Bangladesh is 0.05 mg/L. We assessed groundwater As in an As-affected Sadar Upazilla (small administrative unit) in the District (administrative unit) of Chapai Nabwabganj during 2006, where 50% hand tube well water were above the recommended limit (0.05 mg/L) during dry season. Almost 20% tube well waters were above the recommended limit during rainy season, perhaps due to the dilution of water table. The groundwater in Bangladesh contaminates surface soils and plants thereby As entering the food chain. In 2005, we examined the As levels in different rice varieties grown in different Districts of Bangladesh and the As concentrations in rice grain ranged from 0.07~1.12 mg/kg while the concentrations in 3 rice varieties were above the recommended limit (1 mg/kg rice grain) and the maximum concentration was 1.12 mg/kg rice grain in the rice variety BR 11. With few exceptions, the As content of rice grain in Bangladesh is not considered to be concentration of greater health concern as yet. We also observed enhanced root uptake, efficient root-to shoot translocation, and a much elevated tolerance through internal detoxification all contribute to As hyperaccumulation in a plant, ladder brake fern (Pteris vittata L.). But the phytoremediation technique might not be an appropriate tool to reduce the As calamity in the vast areas of Bangladesh. To mitigate the As problem of Bangladesh, better coordination among governmental agencies and many other organizations will be required to combat the disaster.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.891-903
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• 2017

In recent days, school violence has been rising as a significant social problem. The occurrence of school violence can be fueled by a wide range of social and environmental contexts, thus it is very difficult to come up with the ultimate solution. Community CPTED program is one of the more comprehensive set of efforts that has been developed to prevent crime in general, and the primary focus of the study is to investigate suitable components of CPTED to prevent school violence based on the physical conditions of communities as well as the perception of residents outside of school grounds, in the vicinity of schools. Three sets of analyses in series were employed in the research. First, Ward's minimum-variance cluster analysis was used to classify the places where school violence can occur outside of school grounds based on the physical conditions recognized by local residents. Next, Importance-Performance Analysis was performed to analyze the perception of local residents about the importance and the effectiveness of CPTED components in preventing school violence. Subsequently, Ordered Logit Model was used to analyze the local residents' awareness on safety regarding school violence in their community space. Combining the results of the analyses, the priority of the community CPTED applications to prevent school violence outside of school was derived. Reflecting the local residents' perception on safety of students in their community, the sense of security in communities against school violence can be reinforced by the communities' sensible efforts in creating safer environment for their students.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.1
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• pp.44-52
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• 1982

Recently, estuary reserovoirs have been actively constructed in Korea and also in Japan there are a large number of estuary reservoirs constructed. But most of the estuary reservoirs are located at the downstream of a river where geographical condition is best for the construction of an enclosing dam. And an effective utilization of water from the estuary reservoir seems to be difficult even if estuary reservoirs are considered to be the water resources the most available for their watershed. Studies on estuary reservoirs so far have been mainly concentrated on the physical and engineering problems of the dam construction itself. The purpose of the present study is to review the estuary reservoir planning in connection with the water resources development and to study a basis of the planning. First, the levels of water use in Korea and Japan were compared with those of other countries in the world. And then, some representative reservoirs were selected to study the roles of a reservoir and water-using conditions in the watershed. Based on the study, a survey was given on the relation between a dam construction upstream and an estuary reservoir construction downstream of a river. Finally, a comprehensive examination was made of the bases of estuary reservoir planning. (1) The estuary reservoir planning is deeply related to the plan for water use develo- pment in the watershed. After the upstream water resources were fully developed up to the most, water reso- urces development by an estuary reservoir should be started. (2) If an estuary lake has a capacity big enough, it can store flood discharge of the watershed without any loss and become a basic facility that will bring about the maxi- mum use of water from the watershed. (3) Estuary reservoirs store water used in the upstream watershed, so recycling of water use is attained by the reservoir. Water in the estuary lake is difficult to be fresh water in its long run. Therefore, estuary reservoir should be located at a place where polluted water is purified and refused. All the planning should be based on the assumption that water in the estuary lake is not fresh but polluted after a long time. (4) The estuary lake can only supply water to the lower basin directly. But the upstream area is benefited from the estuary lake by exchange of irrigation water sources between the lower and the upper area. So a large-scale exchange plan between new and existing water resources is important. By constructing estuary reservoirs and the exchange of water sources between upper and lower areas, the reasonable maximum use of water from the whole watershed is at- tained. (5) The big problem coming from the water resources development by an enclosing estuary is salt water intrusion into the lake. To maintain the estuary lake salt-free, multi-purpose use of the lake should be avoided. It is necessary to take such fundamental measures as abolition of back flow operation of gate, and the closing of the fish port and the fish ladder. The results mentioned above were found in this study and these results of this study could be used for the adequate planning of estuary reservoirs in connection with the maximum water use of the watershed.

• Journal of the Korean association of regional geographers
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• v.9 no.3
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• pp.297-313
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• 2003

Problems caused by the U.S. military bases have attracted little attention until recently due to the national security of S.Korea and the peace of North-Eastern Asia, emphasized from the perspective of macro-geopolitics. However, since the political regime has been democratized and political discourses have been liberalized from the 1990s, those problems become a nation-widely serious social issue, though they have been brought about on the local areas. Thus, it can be suggested that micro-geopolitics is highly relevant and significant in approaching the local problems caused by the U.S. military bases, and ultimately resolving the macro-geopolitical problem of longstanding unfair relations in the SOFA and the withdrawal of U.S. troops. This paper aims to consider local problems caused by the U.S. military bases and resolving strategies from the perspective of micro-geopolitics. First of all, it discusses some significance of the micro-geopolitical perspective, as it has been recently emphasized in political geography in considering local problems and politics of life on the basis of place, then looks on empirically criminal and environmental problems caused by the U.S. military bases, analyses the questionnaire date on the perception of local dwellers around the military camps in Nam-gu Daegu, and finally suggests strategies to resolve those problems, which level up from the micro to the macro-scale of geopolitics.

• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.201-212
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• 2012

Objectives : The purpose of this study was to examine about workers' oral health status and oral health behavior practice. Methods : Questionnaire survey was carried out targeting 331 workers within the industrial complex of Jeonju city in 2011. As a result of surveying and analyzing workers' oral health status, habit related to oral health, activity restriction, which is oral disease phase, and oral health practice level by using SPSSWIN 12.0. Results : 1. Workers' experience of visiting dental hospital(clinic) for the past one year was indicated to be the highest with 64.9% in the working period with 10 years-under 20 years(p<0.001). Experience of scaling was indicated to be averagely 38.8%. 2. The oral health status perceived by workers was the highest with 40.5% in 'having something abnormal'. A problem was the highest with 28.0% in 'dental caries'. A cause was indicated to be 42.6% in 'because of being naturally weak in tooth or the gum.' The biggest reason for having failed to receive the dental treatment at a proper time was indicated to be the highest with 24.8% in 'because of feeling burdensome about dental expense. '3. 58.4% of male workers were smoking. The use of dental hygiene device was the highest with 40.6% in mouth-rinse. 4. Absence caused by oral disease was indicated to be the highest with 13.8% in the household income in more than 3,500,000won, thereby having shown the significant difference(p<0.05). Early leaving was indicated to be the highest 13.9% in more than 50s age, thereby having shown the significant difference(p<0.05). Also, as for factors of absence and early leaving, a pain was the highest with 64.7%. 5. Workers' oral health practice level was the highest with 2.85 points in 'Brushing teeth before going to bed'. Conclusions : Synthesizing these findings, the oral management could be known to be made negligently in the workers with the older age, the lower academic background, and the lower income. The institutional foundation is considered to be necessary for which the oral health education can be efficiently performed in addition to a need of periodic oral examination for these classes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5260-5267
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• 2013

In order to create a successful regional development model, there should be an effort to foster a strategic industry which boosts a geographical features of rural areas. Because, It must be clear that the strategic industry chosen between choice and concentration of the development of the local industry development which boosts the local economy revitalization. The local government should have continual concern and roles to fulfil political subjects and keep estimating about the possibility that there could be the sustainable development by Task Ahead of the local industry. This study's indicators were established for the adequacy evaluation of the industrial policy by focusing on domestic regional development's success example. Next, Conjoint analysis was conducted on the Experts. On the basis of this analysis, the weights of indicators are derived. And this study suggest the reasonable evaluation system to take Sustainable industry plan of regional strategic. Consequently, 'Regional development' sector separate 3 categories which are 'Local economy', 'Human Resource Development', 'local marketing' and 9 indicators were derived. 'Industrial development' sector derived 9 indicators about 'Construction of infrastructure', 'Technical development' and 'business support'. Looking through the implications of this study. First, the problem needed to be supplemented based on the Diversity and concreteness of Evaluation system when government assesses regional industry development policy. Second, local government have to strategically consider the possibility of convergence between industries and easiness of network in a broad region. Finally, Foundation and support of the professional manpower and companies for the regional industries must be established.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.255-267
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• 2020

Under SLD conditions, due to the large size of droplets, physical phenomena such as wall-droplet interaction and deformation have a significant effect on the icing process. Accordingly, many studies have been conducted in order to computationally simulate SLD effects. As one of the efforts, post-processing method have been proposed to describe wall-droplet interaction effect, which modified collection efficiency using Wright model. However, since the model doesn't properly consider the wall condition, it still overestimated collection efficiency and impingement limit. To solve this problem, impingement areas were divided into 3 different regions, and the post-processing method was introduced with the new wall-droplet interaction model developed based on Bai and Gosman rebound model. In order to consider the effect of deformation, the most suitable model was selected by comparing the deformation models used in the various icing codes. As a result, the modified post-processing method showed improved accuracy in predicting the impingement limits and collection efficiency by further estimating mass flux loss due to rebound, and it was observed that the result was the closest to the experimental data when the deformation effect was included by using Wiegand model.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.1
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• pp.57-75
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• 2011

This research aimed to explore the effects of collaborative writing activities in a mathematical context, specifically pertaining to areas such as numbers and operation, geometrical figure, and measurement in Mathematics: Level 5-b, on their mathematical achievement gain and disposition among Grade 5 students. To do this, out of a total of 62 students selected from two Grade 5 classes of J Elementary School in Dalseo-gu, Daegu City, who were found to be homogenic from the tests of math performance and dispositions, an experimental group(n=31) was designed and compared to a control group (n=31). Over a six week period from October to November in 2009, the experimental group was given collaborative writing lessons in math classes while the control group was given teacher-oriented regular lessons. The results were as follows. First, there was more or less considerable, though not significant, difference in overall mathematical achievement in the students experiencing collaborative writing activities when compared with the students in the control group. However, in terms of numbers and operation, a sub-category of mathematics, there was significant difference between the two groups. Second, the students experiencing collaborative writing activities were more positively affected in all sub-categories of mathematical disposition: confidence, flexibility, determination, curiosity, reflection, and value, than those in the control group. In summing up, the exposure of collaborative writing activities to mathematics learning was found to help students not only to have a concrete and proper grasp of the relevant problem solving process, which was observed from their mathematical achievement gain especially in the sphere of numbers and operation, but also to have their mathematical disposition set towards more positive direction, which was seen in all sub-categories of mathematical disposition measurement.