• Journal of the Korean earth science society
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• v.38 no.4
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• pp.303-320
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• 2017

Purpose of this study is understanding of group modeling process focusing on constraints with geological field trip applied on social-construction of scientific model. This study was carried out on 12 students of 3 groups who participate in the study 'S' gifted education center. Students were conducted to theme of 'How was formation of Mt. Gwanak?' on 2 field trip classes and 3 modeling classes. Semi-structured interviews, all discourse of field trip and modeling classes, records of personal and group activity were analyzed to constraints based on theoretical background proposed by Nersessian (2008). Results as follows. First, sources of constraints are scientific knowledge, contents observed by students during field trips and additional materials things to be explained by model during modeling class with geological field trip applied on social-construction of scientific model. Second, there are 3 types of constraints to affect making group modeling. It is that shared constraint which used commonly by all the group members. It called selected constraint that used during the initial modeling and later were reflected on for use in the group modeling. And it is that generated constraints, which were not in the initial modeling but were used later in the group modeling. This study suggests that not only the constraints can help to understand of making group model through how they used but also show that example of learning with geological field trip on social-construction of scientific model to contribute school science.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1407-1413
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• 2015

The objective of this study was to investigate the rheological and pasting properties of potato flour dispersions at different concentrations (3, 4, 5, 6, and 7%, w/w). A potato cultivar 'Goun', used in this study, was developed by Highland Agriculture Research Center, RDA. Potato flour dispersions showed shear-thinning behaviors (n=0.44~0.51) at $25^{\circ}C$. Apparent viscosity (${\eta}_{a,100}$), consistency index (K), and yield stress (${\sigma}_{oc}$) significantly increased with an increase in potato flour concentration. Storage modulus (G') and loss modulus (G") significantly increased, whereas complex viscosity (${\eta}^*$) was significantly reduced with increasing frequency (${\omega}$) from 0.63 to 63.8 rad/s. Magnitudes of G' and G" were significantly increased with elevation of potato flour concentration. G' values were considerably greater than G" over the entire range of frequency (${\omega}$) with a high dependence on ${\omega}$. Cox-Merz rule was not applicable to potato flour dispersions. Rapid Visco Analyzer data showed that peak viscosity, trough viscosity, breakdown viscosity, final viscosity, and set back viscosity of samples significantly increased with an increase in potato flour concentration.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.3
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• pp.409-434
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• 2015

The purpose of this study was to investigate the influences of teaching mathematics for social justice on students'interest towards mathematics and perceptions of mathematical values. Eighteen 6th grade students, at B elementary school in Seocho-gu, Seoul, who wished to involved in the study participated in the 10 hour lessons. During the lessons for social justice, the researchers analyzed the students' reactions in the lessons according to the three categories: Perceiving given problematic situations of social conflicts, searching for problem-solving methods based on mathematical analysis, and changing social behaviors to solve life issues through mathematics. They also examined changes of students' interest towards mathematics and perceptions of mathematical values through the activities and reactions using the preliminary questionnaires, observations of lessons, and students' activity sheets. The research results showed that the students perceived mathematics as a tool for social justice in mathematics lessons, tried to find problem-solving methods based on mathematical analysis, and expressed their active social behaviors by cultivating the will of practice to solve life issues through mathematics. Based on those findings, the study reached the following conclusions. First, the students recognize many of the social problems in their societies as social justice regardless of their economic levels. Second, learning activities need to design in a way that students can accept the social problems as realistic situations in teaching mathematics for social justice. Third, students look at the world from a mathematical perspective, have interest in mathematics, and recognize the values of mathematics in teaching mathematics for social justice.

• Journal of The Korean Association For Science Education
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• v.31 no.5
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• pp.694-708
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• 2011

In this study, we developed tasks including cognitive scaffolding for students to explain scientific phenomena using valid evidences in science classroom and sought to investigate how tasks influence the development of small group scientific argumentation. Heterogeneous small groups in gender and achievement were organized in one classroom and the tasks were applied to the class. Students were asked to write down their own ideas, share individual ideas, and then choose the most plausible opinion in a group. One group was chosen for investigating the effect of tasks on the development of small group argumentation through the analysis of discourse transcripts of the group in 10 lessons, students' semi-structured interview, field note, and students' pre- and post argument tests. The discrepant argument examples were included in the tasks for students to refute an argument presenting evidences. Moreover, comparing opinion within the group and persuading others were included in the tasks to prompt small group argumentation. As a result, students' post-argument test grades were increased than pre-test grades, and they argued involving evidences and reasoning. The high level of arguments has appeared with high ratio of advanced utterances and lengthening of reasoning chain as lessons went on. Students had elaborate claims involving valid evidences and reasoning by reflective and critical thinking while discussing about the tasks. In addition, tasks which could have various warrants based on the data led to students' spontaneous participation. Therefore, this study has significance in understanding the context of developing small group argumentation, providing information about teaching and learning context prompting students to construct arguments in science inquiry lessons in middle school.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.771-777
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• 2017

This study investigated the rheological properties of Calrose rice flour dispersions as well as the effects of different thawing methods (steamer, smart oven, and microwave oven) on quality characteristics of frozen turmeric rice. Apparent viscosity, consistency index, and yield stress significantly increased at higher rice flour concentrations. Magnitudes of storage modulus and loss modulus significantly increased with elevation of rice flour concentration. Frozen turmeric rice thawed using a steamer had the highest moisture content and largest size (length, width, and thickness) among all thawing methods. The L values of turmeric rice after thawing using a steamer was significantly higher than those of other thawing methods. The a value of turmeric rice after thawing using a steamer was significantly lower than those of other thawing methods. Textural properties (hardness, adhesiveness, springiness, cohesiveness, brittleness, and chewiness) of frozen turmeric rice after thawing using a steamer were significantly lower than those of other thawing methods. Therefore, it can be concluded that frozen turmeric rice after thawing using a steamer might be desirable for improvement of texture.

• Journal of Educational Research in Mathematics
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• v.27 no.3
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• pp.511-536
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• 2017

The present study aims to investigate ways in which pre-service secondary mathematics teachers anticipate 1) students' responses to specific mathematical tasks which are chosen or devised by the participating pre-service teachers as requiring students' higher cognitive demand and, 2) their roles as math teachers to scaffold students' mathematical thinking. To achieve the goal, we had our pre-service teachers to engage in an adapted version of Spangler & Hallman-Thrasher(2014)'s Task Dialogue writing activity whose focus was to develop pre-service elementary teachers' ability to orchestrate mathematical discussion. 14 pre-service teachers who were junior at the time enrolled in the Mathematics Teaching Method Course were subjects of the current study. In-depth analysis of both Task Dialogues which pre-service secondary mathematics teachers wrote and audiotapes of the group discussions while they wrote the dialogues suggests the following results: First, the pre-service secondary teachers anticipated how students would approach a task based on their own teaching experiences. Second, they were challenged not only to anticipate more than one correct students' responses but to generate questions for the predicted correct-responses to bring forth students' divergent thinking. Finally, although they were aware that students' knowledge should be the crucial element guiding their decision-making process in teaching, they tended to lower the cognitive demands of tasks by providing students with too much guidance which brought forth the use of procedural knowledge. The study contributes to the field as it provides insights as to what to attend in designing teacher education course whose goal is to provide a foundation for developing pre-service teachers' ability to effectively orchestrate mathematical discussion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1227-1240
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• 2014

Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (${\tau}$)-shear rate (${\dot{\gamma}}$) and viscosity(${\eta}$)-shear rate (${\dot{\gamma}}$) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in ${\tau}$-${\dot{\gamma}}$ and and ${\eta}$-${\dot{\gamma}}$ plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.

• Journal of The Korean Association For Science Education
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• v.38 no.1
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• pp.11-26
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• 2018

The purpose of this study is to investigate teachers' responsive practices in whole class discussion after small group argumentation and the underlying epistemological framing. Three teachers and 84 students participated in this study by engaging in argumentation activities about the sensory system. We recorded both their discussions in the classes and our interviews with the teachers, which were transcribed for analysis. The results of the analysis showed that the teachers' responsive practices and the epistemological framing were categorized into four types. By framing the discussion as 'reaching the correct answer through discussion,' the teacher focused on whether students' ideas corresponded to scientific concepts and transferred scientific ideas to the students. By framing the discussion as 'eliciting appropriate conceptual resources and developing them into a scientific idea through critical evaluation,' the teacher engaged in the students' discussion as another participant, and considered the small groups' arguments as resources that could develop into scientific concepts. By framing the discussion as 'sharing small groups' arguments,' the teacher responded by asking for clarification of each group's argument, considering it as a valid argument in its own way. By framing the discussion as 'reaching a consented argument through critical evaluation,' the teacher negotiated students' critical evaluation and revision of the arguments. We explored the implications and limitations of each type of responsive practice and considered that the results of this study will contribute to developing teachers' responsive teaching strategies in argumentation activities.

• Journal of the Korean earth science society
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• v.31 no.3
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• pp.288-299
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• 2010

Recently, scientific literacy means not only the acquisition of scientific knowledge but also the linguistic ability to participate in a scientific discourse community. Keeping this in mind, this study investigated middle school students' writings about phase transitions of water in air. Sixty seven students at 9th grade (age 15) students participated in this study and wrote two individual short texts. The result of text analysis can be summarized as follows: (1) students had problems with familiar scientific terms such as 'water vapor' and 'steam' as well as unfamiliar ones like 'dew point'. (2) Students described right semantic relations and at the same time wrong ones more in the idea formed from everyday experience than those from school instruction. (3) While students showed action and process centered writing in text about everyday phenomenon, they showed more preference for technical words and nouns in text about school science. This study suggest that students could develop linguistic ability of science from both spontaneous process based on experience and formal and theoretical learning; the former in forming various semantic relations, the latter in technical and abstract aspect of scientific writing.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.381-388
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• 2020

This paper discusses English Hedges or Hedging Expressions on the basis of their morphosyntactic-pragramatic properties within the perspective of sociolinguistics. The term, 'Hedges' for the past decades since Lakoff(1973), has received little attention from the English grammar circles such as morphosyntax and the generative grammar theories. This paper presents a more comprehensive approach to the identification, distributions, functions, and the morphosyntactic properties of English Hedges. The earlier research on English Hedges in the 70's show that hedges are metalinguistic or mitadiscourse expressions which constitute a means for executing Politeness strategy in pragmatics. Nonetheless, research from the interface of syntactic-pragmatics has been scarce. This article suggests a more complex body of English hedges that have not been extensively discussed in the literature. Additionally, their configurational domain is to be proposed as part of the PolP with [±hedged] above CP⁺ (or CP beyond). The ramifications of the current study are suggested in terms of comparative linguistics, EFL/ESL studies of English for global communication, and pragmatics-sensitive machine translation studies in the forseeable future.