• Journal of Educational Research in Mathematics
• /
• v.9 no.2
• /
• pp.383-404
• /
• 1999

This study began with an epistemological question about the nature of mathematical cognition in relation to the learner's activity. Therefore, by examining Piaget's 'reflective abstraction' theory which can be an answer to the question, we tried to get suggestions which can be given to the mathematical education in practice. 'Reflective abstraction' is formed through the coordination of the epistmmic subject's action while 'empirical abstraction' is formed by the characters of observable concrete object. The reason Piaget distinguished these two kinds of abstraction is that the foundation for the peculiar objectivity and inevitability can be taken from the coordination of the action which is shared by all the epistemic subjects. Moreover, because the mechanism of reflective abstraction, unlike empirical abstraction, does not construct a new operation by simply changing the result of the previous construction, but is forming re-construction which includes the structure previously constructed as a special case, the system which is developed by this mechanism is able to have reasonability constantly. The mechanism of the re-construction of the intellectual system through the reflective abstraction can be explained as continuous spiral alternance between the two complementary processes, 'reflechissement' and 'reflexion'; reflechissement is that the action moves to the higher level through the process of 'int riorisation' and 'thematisation'; reflexion is a process of 'equilibration'between the assimilation and the accomodation of the unbalance caused by the movement of the level. The operational learning principle of the theorists like Aebli who intended to embody Piaget's operational constructivism, attempts to explain the construction of the operation through 'internalization' of the action, but does not sufficiently emphasize the integration of the structure through the 'coordination' of the action and the ensuing discontinuous evolvement of learning level. Thus, based on the examination on the essential characteristic of the reflective abstraction and the mechanism, this study presents the principles of teaching and learning as following; $\circled1$ the principle of the operational interpretation of knowledge, $\circled2$ the principle of the structural interpretation of the operation, $\circled3$ the principle of int riorisation, $\circled4$ the principle of th matisation, $\circled5$ the principle of coordination, reflexion, and integration, $\circled6$ the principle of the discontinuous evolvement of learning level.

• Journal of the Korean Chemical Society
• /
• v.59 no.1
• /
• pp.78-87
• /
• 2015

The purpose of this study was to investigate the argumentation of middle school students during the argument-based inquiry. A total of sixty eight 8th grade middle school students participated in this study and they performed six argument-based inquiry programs. Data were collected from two of the latest programs by audio-recording and transcription of each group engaging in argumentation. The study findings showed that; first, the most frequent element of argumentation in the all of stages of the two programs was following order: 'claim' and 'request and response' and 'simple agreement'. The most active argumentation was showed at the designing experiments stage and the most inactive was showed at the generating questions stage. Second, as a result of analyzing the argumentation level for each stage of the argument-based inquiry, a high level of argumentation was shown at the claim and evidence stage, and a low level of argumentation was shown at the generating questions stage in the argumentation structure. As a result of the validity of argumentation, the validity of argumentation was the highest level in the claim and evidence stage.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.7
• /
• pp.1604-1618
• /
• 1995

In the process of mechanical assembly design, assembly modeling systems have been used mainly for the design verification before manufacturing by enabling to check the interference and/ or the dynamic and kinematic performance. However, the conventional assembly modeling systems have a shortcoming that they can not be used in the initial design stage but can be used only after the design is fully completed. In other words conventional assembly modeling systems provide bottom-up modeling which means that the detailed modeling of components must precede the definition of relationships between them. To resolve this problem, an assembly modeling system is proposed to provide a top-down modeling environment in which components and assembly can be modeled simultaneously. To this end, an assembly data structure suitable for top-down assembly modeling has been established. Feature positioning Module(FPM) using geometric constraints has been also developed. The Sekective Solving Method proposed for FPM is based on the priority between the constraint equations and enables the designer's intent expressed by geometric constraints to be maintained throughout the whole modeling process. Finally, the feature based modeling technique using two-level features has been developed. Two-level features include an abstract model and a detailed model in a merged form in non-manifold data frame.

• Journal of Information Processing Systems
• /
• v.1 no.1 s.1
• /
• pp.41-48
• /
• 2005

This paper presents the development of a morphological processor for the Mongolian language, based on the two-level morphological model which was introduced by Koskenniemi. The aim of the study is to provide Mongolian syntactic parsers with more effective information on word structure of Mongolian words. First hand written rules that are the core of this model are compiled into finite-state transducers by a rule tool. Output of the compiler was edited to clarity by hand whenever necessary. The rules file and lexicon presented in the paper describe the morphology of Mongolian nouns, adjectives and verbs. Although the rules illustrated are not sufficient for accounting all the processes of Mongolian lexical phonology, other necessary rules can be easily added when new words are supplemented to the lexicon file. The theoretical consideration of the paper is concluded in representation of the morphological phenomena of Mongolian by the general, language-independent framework of the two-level morphological model.

• Journal of Microbiology
• /
• v.33 no.3
• /
• pp.222-227
• /
• 1995

We have examined DNase I sensitivity of .betha.-tubulin and flagellar calmodulin genes which are transiently and coordinately activated differentiation of Naegleria gruberi amebae into flagellates. The DNase I sensitivity of .betha.-tubulin and flagellar calmodulin genes changed in parallel with the changes in transcriptional activity of the respective genes during differentiation. The two genes were resistant to DNase I inamebae stage when transcription of the two genes was inactive. Forthy minutes after initiation of differentiation, when the two genes were most actively being transcribed, the two genes showed the highest sensitsivity to DNase I. One hundred and twenty minutes after initiation, the differentiation was completed and transcriptional activity of the two genes decreased to a low level. At this stage, the two genes were resistant to DNase I treatment like the ones at the amebae stage. This change in the DNase I sensitivity of the two genes was not observed when transcription of the two genes was blocked by adding cycloheximide at the beginning of differentiation.

• Journal of Korean Home Economics Education Association
• /
• v.7 no.1
• /
• pp.29-45
• /
• 1995

The purpose of this study was to investigate eating behavior and the attitude about weight control of the High School Girls. The questionnaires were completed by 519 girls’ high school students.(lived in city ; 269, in mine region ; 250) The results were as follows: 1. The average stature of them was 159.01${\pm}$5.09cm, the average weight was 51.64${\pm}$6.76kg. 2. In the present body structure of them, the underweight structure was 26.2% the normal weight structure was 58.4% the overweight structure was 15.4%. The present body structure was very different from the recognition of their own body structure. 3. The average point of the eating behavior was 52.07 and that of city(53.62 point) was higher than mine region(50.01 point). 4. The rate of going without breakfast(P<0.05) the frequency of snack(p<0.001) the eating rate of stimulus foods(p<0.05) the interest healthy food life(p<0.05) in two regions showed the significant difference. 5. The point of eating behavior in two regions showed the positive correlation in the economic level, the contentment degree of the present body structure, the conscious healthy condition. But it showed the negative correlation in the rate of going without of breakfast. On observing the difference of the tow regions, it showed the positive correlation to mother’s education career on the negative relation to the experience of the weight control in the city. In the other hand it showed the negative correlation to the recognition on degree of the present body structure in the mine region. 6. The contentment degree of the present body structure showed the negative correlation to the experience of the weight control. Also it showed the negative correlation to the rate of going without breakfast in the city.

• Journal of Environmental Science International
• /
• v.21 no.2
• /
• pp.135-144
• /
• 2012

This study aims at classifying and analyzing the vegetation structure of Castanopsis sieboldii forest, one of the evergreen broad-leaved forests found under the warm-temperate climate of Korea. It is also compared with the ones of the Castanopsis sieboldii forest in Japan where most similar such forest of Korea, to find unique vegetation structures of the only Korean forest. Vegetation structure of Korean Castanopsis sieboldii forest was divided into two units at the level of community units both of Ardisia japonica-Castanopsis sieboldii community and Ardisio-Castanopsietum sieboldii association. The association carries similar type with the vegetation system of Japan, but any subunits differentiated with the Japan were found vary much. Hierarchical cluster analysis brings in similar result with the analysis on the vegetation structure as well.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.138-142
• /
• 2001

A comparison between theoretical and measured transfer function, which relates structure-borne noise source level to underwater radiated noise, of a naval ship is presented in this study. Transfer functions are obtained by dividing far field underwater noise by the value of structure borne noise source levels below machinery mounts. In prediction, statistical energy analysis of the whole ship structure is used to get vibration levels of wetted hull plates below water line. Then, far field radiated noise is calculated by summing up contributions from each plates using vibration levels and radiation efficiencies. And 1/3-octave band underwater sound pressure at the distance of 1 m away from the hull were measured to get experimental transfer functions. The two transfer functions are compared to show resonable agreements in spite of the subtle physical differences between each other.

• East Asian Economic Review
• /
• v.23 no.1
• /
• pp.55-88
• /
• 2019

Our paper contributes to existing literature by empirically investigate the trade structure and trade performance between Korea and ASEAN. Overall, trade activities between Korea and almost major ASEAN economies have significantly focused on capital goods, medium and high technology goods, while the remaining ASEAN countries' exports over Korea have been mainly primary and low technology goods. There has been a higher complementarity in between Korea's exports and ASEAN's imports compared with between ASEAN's exports and Korea's imports. Estimation results show that ASEAN's GDP and income have larger impacts than those of Korea on aggregate trade flows as well as sectoral level between two sides. Additionally, geographical conditions are critical factors impeding Korea-ASEAN trade. Meanwhile, other factors in the estimation model have mixed impacts on components of Korea-ASEAN trade structure. Finally, there is a significant room for Korea's trade expansion with ASEAN, particularly new and less developed members in future.

• International Journal of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.10-18
• /
• 2022

Since High Sierra, APFS has been used as the main file system. It is a well-established file system that has been used stably thus far. From the perspective of digital forensics, there are still many areas to be investigated. Apple File System Reference is provided to the apple developer site, but it is not satisfactory to fully analyze APFS. Researchers know more about the structure of APFS than before, but they have not yet fully analyzed its structure to a perfect level about it. In this paper, we develop APFS object identification tool for digital forensics. The most basic and essential object identification and analysis of the APFS filesystem will be conducted with the tool. The analysis in this study serves as the background for an analysis of the checkpoint operation principle and structure, including the more complex B-tree structure of APFS. There are several options for the developed tool, but the results of two use cases will be shown here. Based on the implemented tool, it is hoped that more functions will be added to make APFS a useful tool for faster and more accurate analyses.