• Journal of The Korean Association For Science Education
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• v.33 no.5
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• pp.893-910
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• 2013

The purpose of this study was to identify changes in mental models of students in the elementary school about causes of seasonal changes. During a total of eight sessions, eight sixth graders were asked to describe the causes of seasonal changes through pictures, writing and thinking aloud by using microgenetic research methods, and the changes in mental models were examined. When the research was conducted, linguistic and behavioral factors and contents of interviews of participants were recorded on video. Moreover, a variety of materials such as field observation chart were written by a researcher and mental models records were written by a student. The protocol was written by integration of collected results, and it was repeated to read and was inductively categorized. The results of this study were as follows: First, participants' mental models about causes of seasonal changes were changed in various paths within and across sessions. Participants' mental models that had been more changed in various ways were closer to the scientific model. In addition, like rotation and revolution, students who correctly established the preconceptions related to seasonal changes formed the mental models consistent with scientific concept based on new information. On the other hand, students who did not correctly establish the preconceptions did not deviate from non-scientific mental models. Second, prior knowledge, experience and information which participants held in advance, accuracy of prior knowledge, resolution of inconsistency between new knowledge and existing mental models, activation of mental models through operation of models and drawing an picture affected the changes of mental models. Teachers should provide to learners with sufficient experience which can be configured to various mental models in order to form the scientific concepts. And they need to let learners feel the doubt and resolve it through presentation of new teaching material which is inconsistent with the existing mental models.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.491-495
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• 2008

The purpose of this study is to analyze the characteristics of IT gifted middle school students. The researcher analyzed the observational assessments of 16 gifted noddle school students through 19 education programs conducted from During the latest 3 years at the Science Gifted Children Education Center. The researcher hypothesized that IT gifted children would be outstanding in computer skills and information processing abilities. But they were not much different from gifted children in the other areas. Therefore there are two suggestions resulted from the study. First, it might not be meaningful to sub-categorize the subjects because of their developmental stages. The tenth grade students observed in this study were in their formal operational period by Piaget. Therefore, it would be desirable to teach them integrated areas rather than separated areas. Second, gifted children could be excellent in most areas. Due to their curiosity, task tenacity, and intellectual abilities, they could show excellence in any areas. Therefore, it is important to elaborate the educational programs so that the gifted children can develop their abilities in each areas.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.119-129
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• 2012

Yongdoseo and Guimunwon are described in "Bokgeo(卜居, fixabode)" of "Sanlimkyengje(山林經濟)" written by Manseon Hong. This record is a unique garden conceptual idea applying the principles of Hetu(河圖) and Luoshu(洛書), fanciful gardens which have not been actually constructed. Here, two garden types were concretely described respectively, however the underlying meaning therein cannot be apprehended without exact understanding about Sangsu studies. Therefore, the purpose of this study is to illuminate the meaning contained in Garden illustration and the historical meaning of landscape therein through considering this text. To achieve the purpose of this study, the writer and the compiler who are the background of this writing and the outline of Sangsu studies were investigated. Also, the principles of Saengsu(生數), Seongsu(成數), Yin Yang(陰陽), Four Bodies(四象), Palgwedo(八卦圖), etc. which are in Hetu and Luoshu were considered. The result of this study went through this research process is summarized as follows. First, Hetu Luoshu are conceptual definitions which wholly abstracted the basic propositions of Sangsu philosophy such as the universe change principle, etc., while Yongdoseo and Guimunwon can be said to be operational definitions which apply those as garden composition principle, enabling to experience the meaning contained therein concretely and explain it in a replicable way. This attempt is a unique example, unprecedented in Chinaas well. Second, as a livingspace, garden was selected as a means to concretize operational definitions about the meaning of Hetu Luoshu, and as the property to reproduce the bearings concept, the location and the number, etc. of Hetu Luoshu, Taegukjeong(太極亭), Shipjagak(十字閣), Dondae(墩臺), well, pond as well as various kinds of trees were used. Third, the main motif of Yongdoseo and Guimunwon is the relation between Apriority(先天) and Posterior(後天), and the relation between Constitution(體) and Use(用) of Hetu and Luoshu respectively. That is, Yongdoseo planted evergreen trees such as Shipjangcheong(十長靑) in order to symbolize the universe creation principle which Hetu stands for, i.e. silent, harmonious, orderly and win-win image. In Guimunwon, flowering trees(花木) and fruit trees(果木) were planted freely to express the change of Posterior which Luoshu stands for, thatis, dynamic, disharmonious, disorderly, incompatible(相剋) and changing image. The effects intended to be attained through such planting were, 'freshness and cheerfulness(淸爽)' of Yongdoseo and 'splendidness' of Guimunwon respectively. Sangsu studies based on Hetu and Luoshu is a unique thinking system to the Orient which came from the accumulated wisdom of several scholars from various schools through a long period since ancient times. Therefore, the concept and the theory thereof are profound and huge, and its viewpoints of interpretation are diverse. It is a limit of this study that more in-depth and various consideration was not performed. As a further research project, more empirical study of Orientalism such as Sangsu studies, etc. inherent in Traditional Garden is necessary.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.267-272
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• 2010

Screw-in effect is one of the unintended phenomena that occurs during the root canal preparation with nickel-titanium rotary files. The aim of this study was to compare the screw-in effect among various nickel-titanium rotary file systems. Six different nickel-titanium rotary instruments (ISO 20/.06 taper) were used: $K3^{TM}$ (SybronEndo, Glendora, CA, USA), $M_{two}$ (VDW GmbH, Munchen, Germany), NRT with safe-tip and with active tip (Mani Inc., Shioya-gun, Japan), ProFile$^{(R)}$ (Dentsply-Maillefer, Ballaigues, Switzerland) and ProTaper$^{(R)}$ (Dentsply-Maillefer, Ballaigues, Switzerland). For ProTaper$^{(R)}$, S2 was selected because it has size 20. Root canal instrumentations were done in sixty simulated single-curved resin root canals with a rotational speed of 300 rpm and single pecking motion. A special device was designed to measure the force of screw-in effect. A dynamometer of the device recorded the screw-in force during simulated canal preparation and the recorded data was stored in a computer with designed software (LCV-USE-VS, Lorenz Messtechnik GmbH, Alfdorf, Germany). The data were subjected to one-way ANOVA and Tukey's multiple range test for post-hoc test. P value of less than 0.05 was regarded significant. ProTaper$^{(R)}$ produced significantly more screw-in effects than any other instruments in the study (p < 0.001). $K3^{TM}$ produced significantly more screw-in effects than $M_{two}$, and ProFile$^{(R)}$ (p < 0.001). There was no significant difference among $M_{two}$, NRT, and ProFile$^{(R)}$ (p > 0.05), and between NRT with active tip and NRT with safe one neither (p > 0.05). From the result of the present study, it was concluded, therefore, that there seems significant differences of screw-in effect among the tested nickel-titanium rotary instruments. The radial lands and rake angle of nickel-titanium rotary instrument might be the cause of the difference.