• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.607-613
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• 2006

For the reasonable use of low grade-shallow geothermal energy by Standing Column Well(SCW) system, the basic requirements are depth-wise increase of earth temperature like $2^{\circ}C$ per every 100m depth, sufficient amount of groundwater production being about 10 to 30% of the design flow rate of GSHP with good water quality and moderate temperature, and non-collapsing of borehole wall during reinjection of circulating water into the SCW. A closed loop type-vertical ground heat exchanger(GHEX) with $100{\sim}150m$ deep can supply geothermal energy of 2 to 3 RT but a SCW with $400{\sim}500m$ deep can provide $30{\sim}40RT$ being equivalent to 10 to 15 numbers of GHEX as well requires smaller space. Being considered as an alternative of vertical GHEX, many numbers of SCW have been widely constructed in whole country without any account for site specific hydrogeologic and geothermal characteristics. When those are designed and constructed under the base of insufficient knowledges of hydrgeothermal properties of the relevant specific site as our current situations, a bad reputation will be created and it will hamper a rational utilization of geothermal energy using SCW in the near future. This paper is prepared for providing a guideline of SCW design comportable to our hydrogeothermal system.

• Journal of Korean Elementary Science Education
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• v.41 no.2
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• pp.173-185
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• 2022

The purpose of this study is to present a reflective review of the earth and universe units from the revised elementary curriculum of 2007-2015 and suggest changes in the 2022 revised curriculum. For this purpose, we conducted an FGI with earth science educators and elementary school teachers regarding the content elements and system, the achievement standards and inquiry activity composition, and the vertical and horizontal curriculum connectivity. Free response and weighted hierarchical analysis items were incorporated into the FGI to ensure logical consistency of the inductively derived improvement. This analysis revealed that the composition of units by grade group had been unevenly distributed among each of the "earth systems" until the 2015 revised curriculum was finalized. Furthermore, the basic concept was still insufficient. We suggest that achievement standards centered on the learning content and skills must state specific scientific core competencies, and inquiry activities should include rigorous critical thinking, student written responses, and student inquiry and analysis. In the hierarchical analysis items, FGI emphasized the inclusion of essential content elements rather than reduction of content elements, understanding-oriented concept learning rather than interest-centered phenomenon learning, basic concept division learning before integration between subjects, and expanding vertical-horizontal connectivity rather than repeating and advancing learning. There is a limit to the generalizing the suggestions proposed in this study to the common opinion of elementary earth science experts. However, since the main vision of the 2022 revised curriculum is to gather opinions through educational entities' participation in a variety of educational subjects, it is suggested that our results should be incorporated as one of the opinions proposed for the 2022 curriculum revision.

• Journal of Chest Surgery
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• v.38 no.4 s.249
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• pp.284-290
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• 2005

We evaluated the early and mid-term results for repair of Ebstein's anomaly. Material and Method: Between January 1989 and June 2004, 29 patients underwent repair of Ebstein's anomaly. The median age was 11.4 years (4 days-50 years). Tricuspid insufficiency equal to or greater than grade 3 was present in 21 $(72.4\%)$ patients. Surgical techniques included tricuspid valve repair with vertical plication of the atrialized ventricle (n=14), Carpentier's technique (n=7), tricuspid valve replacement (n=4), systemic-to-pulmonary arterial shunt (n=2), tricuspid valve repair (n=1), and Fontan operation (n=1). Bi-directional cavopulmonary shunt (BCPS) was required in 5 patients. Among the 2 neonates, one patient underwent successful biventricular repair, and the other patient underwent systemic-to-pulmonary arterial shunt. Follow-up was possible in 21 patients $(75\%)$, and the average follow-up was 37.6 months (3 months-11.3 years). Result: There were $1(3.4\%)$ early and 1 late deaths. Reoperation was required in 4 patients. Two patients underwent tricuspid valve re-replacement, and the other 2 tricuspid valve repair. At recent follow-up, only 2 patients showed tricuspid insufficiency equal to or greater than grade 3, and most patients showed clinical improvement. Excluding the patients who underwent tricuspid valve replacement, the actuarial rate of freedom from reoperation at 1 and 5 years were $94.7\%\;and\;79.0\%$, respectively. Conclusion: Tricuspid valve repair was possible in most patients with good mid-term outcome. Most patients showed clinical and hemodynamic improvement. Indications for the BCPS should be clarified.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.2
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• pp.89-100
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• 2021

This study evaluated the degree of interaction between the people and the environment using perceived naturalness measure. The seventh-grade index of Hemeroby was divided into subclasses of land cover according to degrees of human influence. The grade was standardized for each indicator to evaluate the current state of urban parks in Seoul by applying probability density function and weight. User evaluation was conducted on six distinctive parks selected. In the results, three implications were found between spatial evaluation according to the perceived naturalness. First, park users evaluated highly for the spaces such as broad-leaved forest, coniferous forest and mixed forest evaluated highly in the Hemeroby grade index. Park users generally recognized that various types of trees in the area had high naturalness. The density of trees is one of the factors in perceived naturalness. Second, water spaces were highly evaluated for naturalness in the Hemeroby grade index. However, the perceived naturalness of water spaces such as inland wetlands, pond and reservoir evaluated in various ways depending on environmental conditions around the park. Third, perceived naturalness is easily evaluated through vertical landscape elements such as trees rather than horizontal landscapes such as grassland. The perceived naturalness is similar to the naturalness evaluation using land cover. However the study found the perceived naturalness for a specific space was different from the Hemeroby index. Perceived naturalness by the user includes the content that the individual sees, hears, and experiences. Park users are usually structuring naturalness through evaluating the value of urban green spaces based on personal perception. Therefore there is no absolute standard criterion for evaluating the naturalness of urban green spaces. A deeper study is needed that considers user bundles or user groups with conflicting interests on the perceived naturalness in urban parks. These studies will be essential data on the direction of naturalness urban park service should provide.

• Journal of Science Education
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• v.42 no.1
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• pp.27-48
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• 2018

The purposes of this study are to derive suggestions and implications to improve the continuity of Korean Science & Practical Arts (Technology Home Economics) curricula through international comparative analysis with focus on the science curricula or standards in five countries (Canada, New Zealand, Singapore, the United States, Korea). Original documents of the national curriculums or standards of each country collected from NCIC comparatively analyzed the big concepts of the 'system' and 'energy' based on features of related components of curriculum contents, vertical, and lateral connectivity. The results indicated that the big concepts of systems and energy were used internationally to consider the curriculum continuity. In most countries, the big concept of system was used as a framework to integrate science with technology or other contents. In particular, it was also utilized to strengthen vertical and lateral connectivity in earth science and space science contents area. In the comparison of countries for the system as the big concept, New Zealand focused interrelationship between system and human activities, systems' interaction, levels and features of system concept for the linkage between grades and subjects on the basis of level. In the case of Canada and Singapore, science and technology are combined to strengthen contents' connection. However, the revised 2015 curriculum has a lack of continuity and sequence because the concepts of system and energy were concentrated on a specific grade and contents' area. The curriculum was not developed systematically for multiple grades according to their levels. In conclusion, Korean science curriculum requires sufficient understanding of students' learning and research on learning progressions and curriculum continuity. In addition, it is very important to constitute the curriculum based on the vertical and lateral connectivity in order to improve science education and to foster students' key competencies and abilities.

• Journal of The Korean Association For Science Education
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• v.35 no.5
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• pp.805-815
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• 2015

The Korean education curriculum is making efforts to improve education to foster competencies that the future society demands through the 2007 and 2009 revised curriculum. The revised curricula focus on enhanced articulation for the quality curriculum. In this study, the curriculum is analyzed for vertical and horizontal articulation. In addition, the study found a problem in Korea's curriculum through international comparison and sought improvement. Furthermore, the study compared internationally articulation of the concept of photosynthesis, of which the results are as follows. First, our science curriculum focuses on vertical articulation and has relatively neglected the problem of horizontal articulation. To compensate for this problem, curriculum design should introduce aspects of 'nature' and 'environment' and should consider the interests and concerns of students, as countries with high horizontal articulation do. Second, the actual education field has a problem with the a lack of continuity and sequence because of concentration of concept in a specific grade or simply repeating the concept across multiple grades. These results have led to alternative proposals that should arrange basis of concept configuration such as 'Big Idea' and should establish the adoption of 'systems' frequently appearing in the other curricula. Finally, there may be mentioned a lack of research on students' learning progression, which can be a common standard of horizontal and vertical articulation. Research on learning progression has been a trend overseas, but there exists no study to fit Korea's situation, so education fields need to conduct the appropriate research on learning progression as part of the commitment to high-quality curriculum.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.19-29
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• 2008

The main purpose of this study is to introduce Hauer's(2004) approach that overcomes current accident prediction models' limitation and to apply this approach to Korean situation using fatal accident data on motorways. After developing accident prediction models according to this approach, it is found that AADT and vertical grade could improve fitness of the model, whereas a radius of roads is not related to the number of accidents. The advantage of Hauer's approach is to reduce possibility to eliminate critical variables and to keep uncritical variables when we consider many variables to develop accident prediction models.

• International Journal of Highway Engineering
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• v.10 no.2
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• pp.125-133
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• 2008

Achieving consistent geometric design is an important goal in highway design to ensure obtaining safe, economical and smooth traffic operation. Most evaluation of consistency is based on 'speed change' in speed profile. According to literature, the speed depends on geometric elements, speed on tangent section prior to a curve, and background around roads. Especially, the radius is the most main element mentioned in various literature. Therefore, this paper shows two ways of calculating horizontal radius on real road, that is, three-dimensional road. First of all, the radius of horizontal curve is calculated based on physical method. The calculated radius contains not only superelevation but also longitudinal grade while the current minimum radius is calculated by considering superelevation and side friction according to the point-mass equation. Secondly, the problem of composed curves with distorted appearance by overlaying sag or crest vertical alignment has been known. To quantify the extent of distortion effects, the method of calculation of real seen so called 'Perspective Radius' is developed. The paper presents the perspective radius and recommended perspective radius.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.143-149
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• 2017

According to traffic accidents statistics, the number of fatalities, injuries and the rate of increase of traffic accidents have been decreasing over last 5-years. The fatality rate is 1.9 for total accidents but the fatality rate for single vehicle accidents shows a 7.9, which is 4 times greater than the average for all accidents. Single vehicle accidents, usually occur as a vehicle impacts a fixed objects on the roadside as the vehicle runs-off from the road. However, few researches have been conducted considering the accident severity of single vehicle accidents which impact to the fixed objects on the road. The single vehicle accident is directly related to the composition of road cross section, (since it is the required the minimum width of a road for all run-off-the-road vehicles to recover or come to a safe stop). Therefore, this study analyzes the influence of road cross section on traffic accidents to find out the severity of single vehicle accident. To analyze the road elements which are related to the accident severity, the Ordered Probit Model was used. As variables, the element of road cross section such as the radius(m), vertical curve(%), cross sectional grade(%), road width(m). number of climbing lane, median, and curb, were used (as was the 3-years of accidents data). This study found out that cross slope(%), road width(m), and the number of climbing lane are related to the severity of accident. The result of this study could be expected to improve the road safety and to be used as the base data for further road safety research.

• Journal of the Korean Applied Science and Technology
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• v.23 no.4
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• pp.328-339
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• 2006

The PU flame-retardant coatings (TTBAH, ATBAH-10C, -20C, and -30C) were prepared using the synthesized ATBAs and HDI-trimer as curing agent at room temperature. The physical properties of PU flame-retardant coatings with chlorine and phosphorus were inferior to those with phosphorus only and the properties were getting worse with increasing chlorine content. Flame retardancy was tested with three methods. With the vertical method, complete combustion time of ATBAHs were $259^{\sim}347$ seconds, which means that the prepared coatings are good flame-retardant. With the $45^{\circ}$ Meckel burner method, char lengths of the three prepared coatings were less than 2.9 cm, which indicates that the prepared coatings are first grade. With the limiting oxygen index (LOI) method, the LOI values of the three prepared coatings were in the range of $30^{\sim}35%$, which proves good flame retardancy of the prepared coatings. from the result of flame retardancy tests of the specimens that contain the same amounts of flame retarding compounds. it was found that the coatings containing both phosphorus and chlorine show higher flame retardancy than the coatings containing only phosphorus. This indicates that there exists, some synergy effect between coexisting phosphorus and chlorine.