• Analytical Science and Technology
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• v.28 no.2
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• pp.117-124
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• 2015

Genetically modified (GM) papaya line 55-1, which is resistant to PRSV infection, has been marketed globally. Prompt and sensitive protocols for specific detections are essential for the traceability of this line. Here, an event- and construct-specific real-time polymerase chain reaction (RT-PCR) method was established to detect 55-1. Qualitative detection was possible for fresh papaya fruit up to dilutions of 0.005% and 0.01% for the homozygous SunUp and heterozygous Rainbow cultivars, respectively, in non-GM papaya. The method was applied in the qualitative detection of 55-1 in eight types of commercially processed papaya products. Additionally, papaya products were monitored to distinguish GM papaya using the P35S and T-nos RT-PCR detection methods. As expected, detection capacity was improved via modified sample preparation and the established RT-PCR detection method. Taking these results together, it can be suggested that a suitable method for the extraction and purification of DNA from processed papaya products was established for the detection of GM papaya.

• Journal of The Korean Association of Information Education
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• v.15 no.4
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• pp.533-542
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• 2011

In this paper, we have selected traveling algorithms of Line-Tracer as the focused learning elements with the PBL-based programming instruction method. Line-Tracer traveling algorithm programming has been simulated using the Scratch EPL. Development of robot web courseware such as Line-Tracer can create an effective educational environment and also provide solutions for lack of environmental conditions, such as time or spatial factor restrictions and excessive expense issues; these are major obstacles to developing robot programming education. Finally, we analyzed the effects on growth of student's logical thinking and problem solving abilities by demonstrating the Scratch application courseware to the field of elementary education.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.483-495
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• 2011

In modern society, the range of time and space in life is continually expanding due to increase of income and diversification of life. In order to respond to these changes and to satisfy needs and to secure the mobility of citizens, the construction of transport infrastructure and public transport services should be provided continually. In particular, to ensure mobility during late-night hours, providing metropolitan public transport services is urgently needed. Due to expansion of life zone, tension of time and space of metropolitan transportation is essential to construct transport infrastructure in preparation for entry into 24-hour community. This study was based on analysis of travel resource and survey data conducted by passengers of express trains, conventional trains, and metropolitan bus. This study is to investigate use characteristics of passengers and characteristics and problems of Gyeongin-line. Moreover, this study's purpose is to suggest plans in order to improve express train operation and extend hours of the midnight express. It is also important to vitalize public transportation.

• Journal of The Korean Association of Information Education
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• v.14 no.3
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• pp.301-310
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• 2010

In this paper, to instruct elementary programming concepts based on flowchart programming for elementary school students, we proposed sensor-based elementary robot programming PBL problems using line-tracer robots. Proposed PBL problems are designed to have various correct-answer algorithms. For this purpose, we present PBL-based robot programming instruction steps. Through applying the proposed sensor-based PBL problems using line-tracer robots, experimental results are analyzed in views of the problem-solving ability and suitability of allocating degrees of difficulties to the proposed elementary robot programming problems.

• Journal of Educational Research in Mathematics
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• v.17 no.2
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• pp.163-177
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• 2007

Studies on mathematically gifted students have been conducted following Krutetskii. There still exists a necessity for a more detailed research on how these students' mathematical competence is actually displayed during the problem solving process. In this study, it was attempted to analyse the algebraic thinking process in the problem solving a peg puzzle in which 4 mathematically gifted students, who belong to the upper 0.01% group in their grade of elementary school in Korea. They solved and generalized the straight line peg puzzle. Mathematically gifted elementary school students had the tendency to find a general structure using generic examples rather than find inductive rules. They did not have difficulty in expressing their thoughts in letter expressions and in expressing their answers in written language; and though they could estimate general patterns while performing generalization of two factors, it was revealed that not all of them can solve the general formula of two factors. In addition, in the process of discovering a general pattern, it was confirmed that they prefer using diagrams to manipulating concrete objects or using tables. But as to whether or not they verify their generalization results using generalized concrete cases, individual difference was found. From this fact it was confirmed that repeated experiments, on the relationship between a child's generalization ability and his/her behavioral pattern that verifies his/her generalization result through application to a concrete case, are necessary.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.3
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• pp.23-35
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• 2013

It is very important that the calculation of railroad track capacity in infrastructure investment analysis and train operation planning. The dwelling time is one of the factors that influence in railroad track capacity. Current research in dwelling time has been focusing on theoretical investigation, the state of the research in effective variable (dwelling time etc) is insufficient. In this paper, we clearly draw the concept of railroad track capacity and the estimate on modeling of relationship railway demand and dwelling time. Also, we compare and analyze the variation of railroad track capacity according to transit railway demand in Gyeongin Line (Guro~Inchon). This paper is expected to contribute for improving on the in-using equations and methods in train operation planning as well as for improving level of service on railway user.

• Journal of Korean Elementary Science Education
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• v.40 no.1
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• pp.100-112
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• 2021

Based on the importance of visual representation for scientific understanding, this study applied visual thinking in elementary science classes. This study analyzed elementary students' visual thinking and investigated the instructional influences. Students' perceptions on the class applying visual thinking were also investigated. The subject were 38 fourth grade students, 18 in experimental group and 20 in control group. For the unit of 'Shadow and mirror', on-line and off-line blended classes were applied in both group because of COVID-19. The experimental group student were asked to construct their own visual thinking, while the control group students used traditional workbook. The results were as follows. First, students' visual thinking can be classified into three different types, which are 'activity recall type', 'result summary type', and 'core concept representation type' based on what they represent rather than how they represent. Second, applying visual thinking in science class showed significant effects on science academic achievement, science related attitude, and creative academic efficacy. Third, students' perceptions on applying visual thinking in science classes were very positive. Students perceived visual thinking activities were interesting and helpful for understanding science. Educational implications of applying visual thinking in elementary science classes were discussed.

• 한국정보교육학회:학술대회논문집
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• 2009.08a
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• pp.107-112
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• 2009

본 논문의 목적은 초등학생들의 커뮤니티 프로그램 사용 빈도가 인터넷 중독에 미치는 영향을 파악하는 것이다. 본 논문은 초등학교 5, 6학년 학생들을 대상으로 각종 커뮤니티 프로그램의 사용 빈도를 조사하고 그 결과에 따라 커뮤니티 프로그램 사용 빈도가 비교적 적은 집단과 사용 빈도가 많은 집단을 나누어 정보통신윤리 의식 및 인터넷 중독 진단에 많이 사용되는 K-척도를 활용하여 진단을 시행한 후 결과를 분석하였다. 연구 결과, 커뮤니티 프로그램 사용 빈도가 많을 수 록 인터넷 중독 위험성이 큰 것으로 나타났다. 또래집단과의 원활한 커뮤니케이션과 정보 공유 등에 좋은 영향을 미치는 커뮤니티 프로그램이지만 적지 않은 시간을 할애하고 집중함으로써 인터넷 중독의 위험에 빠질 수 있음을 알고 이에 대한 대책을 마련해야 할 것으로 판단된다.

• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.613-627
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• 2014

Elementary textbook ${\ll}Mathematics\;4-2{\gg}$ first published in 2014 according to the 2009 elementary mathematics curriculum has been dealing with concave polygons which were not treated in elementary textbooks according to the previous curriculum. However, n the present paper, to show that there is a need to reconsider the handling of the concave polygons, after discussions about the polygon, problems in handling the concave polygons were discussed in next two viewpoints: Does 2009 elementary mathematics curriculum allow handling of the concave polygons? are there any logical leaps in handling of the concave polygon? And the following reasons to reconsider the handling of the concave polygons are presented as conclusions. First, there was no process of publicizing the handling of the concave polygon. Second, the evidences that will justify the handling of the concave polygon can not be found in 2009 elementary mathematics curriculum. Third, there are logical leaps in the handling of the concave polygons. Fourth, there is no consistency in handling the concave polygons.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.240-247
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• 2018

This study was carried out to determine the levels of lead and cadmium as found in nine agricultural products (n = 578) sold in Korea, and to estimate the risk to human health that is summarily associated with their intake. The concentrations of Pb and Cd were measured using an ICP-MS after microwave digestion in this study. The average contents of Pb and Cd were measured as 0.014 and 0.017 mg/kg for barley, 0.006 and 0.005 mg/kg for mung bean, 0.008 and 0.007 mg/kg for kidney bean, 0.010 and 0.004 mg/kg for green bean, 0.008 and 0.001 mg/kg for pineapple, 0.016 and 0.002 mg/kg for apricot, 0.015 and 0.002 mg/kg for Japanese apricot, 0.021 and 0.002 mg/kg for plum and 0.019 and 0.003 mg/kg for jujube, respectively. The levels of Pb and Cd in the study samples were less than the maximum residual levels established by the European Union (EU), CODEX, and the Korea Food Code. As we have seen, the daily dietary exposures of Pb and Cd from these agricultural products for the general population were noted as 0.067% of PTWI ($25{\mu}g/kg$ b.w./week) and 0.28% of PTMI ($25{\mu}g/kg$ b.w./month), respectively. In line with the study conclusions, these results suggest that the current dietary intakes of Pb and Cd from these agricultural products in Korea have no appreciable risk effects on health for humans as noted in this experiment.