• KSBB Journal
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• v.10 no.4
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• pp.358-369
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• 1995

A mathematical model using local thermodynamic equilibrium isotherms for adsorption in encapsulated adsorbent is proposed in order to optimize the design parameters in situ bioproduct separation process. The model accurately follows the experimental data on the adsorption of berberine, secondary metabolite produced in Thaictrum rugosum plant cell culture. The adsorption rate on encapsulated adsorbent is compared with that on alginate-entrapped adsorbent. The result shows that the higher loading capacity in encapsulated adsorbent is mainly due to the increase in the maximum solid phase concentration. Based on the adsorption rate and loading capacity, the encapsulated adsorbent would be more useful than the entrapped adsorbent when used in situ bioproduct separation process. Design parameters in situ bioproduct separation process, such as the size of the capsule, membrane thickness, the ratio of capsule volume to bulk volume, the ratio of single capsule volume to total capsule volume and the adsorbent content in the capsule, are evaluated by using the model. The ratio of single capsule volume to total capsule volume is the most effective parameter for adsorption of berberine on encapsulated adsorbent.

• Research in Mathematical Education
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• v.10 no.3 s.27
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• pp.205-213
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• 2006

In this research, we interviewed primary school teachers and students with hypothetical situations questions and got a comprehensive picture of the status quo of what is happening in the new mathematics classrooms of Mainland China, that is, teachers' conceptions of mathematics and their teaching approaches influence the students' conceptions of mathematics to a large extent. For the teacher who emphasizes the precision and rigidity of mathematics, her students focus on the superficial characteristics of mathematics. On the contrary, for the teacher who believes that mathematics is an open process, related to real life and rich in content, her students are more interested in mathematics and have more diverse conceptions.

• Communications of Mathematical Education
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• v.20 no.1 s.25
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• pp.87-101
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• 2006

Gifted students in elementary, middle and high schools require a specialized curriculum to foster their mathematically gifted natures. Questions that stimulate the teacher's intellectual curiosity, student reactions and methods pertaining to content organization and problem formation are the main foci.

• Research in Mathematical Education
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• v.14 no.4
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• pp.333-345
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• 2010

This study focuses on student engagement in Chinese middle school mathematics classrooms. By the recording and quantitative analysis on video case, this study explored the main acts and time of student engagement. The data showed that among the student engagements: (1) Students' responses to teacher's question occurred most frequently; (2) Collective responses were much more than the individual responses; (3) Students' responses and classroom practice spent the longest time; (4) The most frequent student engagements occurred in the aspects of classroom practice; and (5) Students rarely asked a question to teachers. The study also suggested that teacher's effective guidance could improve the level of student engagement and the content of classroom practice is very important to the quality of student engagement.

• Research in Mathematical Education
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• v.24 no.3
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• pp.201-228
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• 2021

Teacher noticing has been termed consequential to teaching because what you see and do not see impacts decisions made within the classroom. Further, how a teacher responds to student thinking depends on what a teacher sees in student thinking. Within this study we sought to understand what teachers noticed within an engineering lesson and the decisions made as a result of that noticing. Findings indicate that student teachers and cooperating teachers drew on their pedagogical knowledge for decisions, rather than taking up the integrated content of student thinking and understanding. These findings serve as a guide for the experiences needed to engage in the complex work of teaching or, more specifically, implementing engineering into instruction through a responsive teaching frame.

• Research in Mathematical Education
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• v.25 no.3
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• pp.175-188
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• 2022

Measurement has been an important part of mathematics content students must learn through their schooling. Many studies suggest students' weak measurement learning, particularly related to length measurement, on the part of lower grade students. This difficulty has been attributed to mathematics curriculum as well as instruction. Building on a view of teaching as an interactive activity, this paper explores how a first grade teacher interacted with her students in small groups in a length measurement lesson to promote conceptual understanding as well as procedural fluency. I found that even though the teacher supported students to explain and justify what they understood, the ways the teacher interacted with students were not effective to promote students' understanding. Even though this finding is based on an analysis of a single mathematics lesson, it provides an example of challenges in promoting students' understanding through interaction with students in the context of teaching length measurement.

• Communications of Mathematical Education
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• v.26 no.3
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• pp.251-271
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• 2012

The purpose of this study is: 1) to determine error sources and the effects of each error source, 2) to investigate optimal measuring conditions from holistic and analytic scoring methods, and 3) to compare the value of reliability between Cronbach's alpha and the generalizability coefficient in self-introduction letter and teacher's recommendation letter based on the generalizability theory in identification of mathematical gifted students by observations and nominations. Data of this study were collected from the science education institute for the gifted attached to the university located within in a capital city for the 2011 academic year. Scores form two raters using holistic and analytic scoring methods in both assessment types were used. The results of this study were as follows. First, as to both assessment types, error sources for people were relatively large regardless of scoring methods. However, error sources for raters in holistic scoring methods had a more significant impact than those of analytic scoring methods. Second, to set optimal measuring conditions in the self-introduction letter and teacher's recommendation letter, if we fixed the number of raters into 2 based on holistic scoring methods, at least 5 and 10 content domains were needed, respectively. In addition, the number of items in teacher's recommendation letter should be more than 3 when we fixed the number of content domains into 4, and the number of items in self-introduction letter should be more than 8 when we fixed the number of content domains into 6 using analytic scoring methods. Third, Cronbach's alpha having only a single source of errors was higher than the generalizability coefficient regardless of assessment types and scoring methods. Hence we recommend that generalizability coefficient based on various error sources such as raters, content domains, and items should be considered to keep a satisfactory level of reliability in both assessment types.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.408-413
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• 1992

This study was conducted to determine the effect of the homogenizing grade of sample on absorbance of near infrared reflectance spectrophotometer with which chemical compositions of food were rapidly and effectively analyzed. By the mathematical treatment of absorbance values standard error of prediction was reduced as follows. 1. The absorbance values of various samples ground for the same periods of time were calibrated before or after treatment with first or second derivative in an attempt to accurately predict the components of samples ground for the different periods of time. The standard error of prediction for moisture content were 1.478%, 0.658% and 0.580%, respectively, those for fat content 0.949%, 0.637% and 0.527%, respectively, and those for protein content 0.514%, 0.493% and 0.394%, respectively. Calibration of absorbance values after second derivative treatment showed the highest accuracy in predicting sample components. 2. The absorbance values of various samples ground for the different periods of time were calibrated before or after treatment with first or second derivative in order to accurately predict the components of samples ground for the different periods of time. The standard error of prediction for moisture content were 1.026%, 0.589% and 0.568%, respectively, and those for protein content 0.860%, 0.557% and 0.399%, respectively. The standard error of prediction were lower in the order of calibrations before and after first and second derivative treatments. As a result, calibration of absorbance values after second derivative treatment showed higher accuracy regardless of grinding time of samples.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.1
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• pp.215-241
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• 2017

This study analyzed teachers' Pedagogical Content Knowledge (PCK) regarding the pedagogical aspect of the instruction of ratio and rate in order to look into teachers' problems during the process of teaching ratio and rate. This study aims to clarify problems in teachers' PCK and promote the consideration of the materialization of an effective and practical class in teaching ratio and rate by identifying the improvements based on problems indicated in PCK. We subdivided teachers' PCK into four areas: mathematical content knowledge, teaching method and evaluation knowledge, understanding knowledge about students' learning, and class situation knowledge. The conclusion of this study based on analysis of the results is as follows. First, in the 'mathematical content knowledge' aspect of PCK, teachers need to understand the concept of ratio from the perspective of multiplicative comparison of two quantities, and the concept of rate based on understanding of two quantities that are related proportionally. Also, teachers need to introduce ratio and rate by providing students with real-life context, differentiate ratios from fractions, and teach the usefulness of percentage in real life. Second, in the 'teaching method and evaluation knowledge' aspect of PCK, teachers need to establish teaching goals about the students' comprehension of the concept of ratio and rate and need to operate performance evaluation of the students' understanding of ratio and rate. Also, teachers need to improve their teaching methods such as discovery learning, research study and activity oriented methods. Third, in the 'understanding knowledge about students' learning' aspect of PCK, teachers need to diversify their teaching methods for correcting errors by suggesting activities to explore students' own errors rather than using explanation oriented correction. Also, teachers need to reflect students' affective aspects in mathematics class. Fourth, in the 'class situation knowledge' aspect of PCK, teachers need to supplement textbook activities with independent consciousness and need to diversify the form of class groups according to the character of the activities.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.359-366
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• 2010

In this study, we developed a global ionosphere model based on measurements from a worldwide network of global positioning system (GPS). The total number of the international GPS reference stations for development of ionospheric model is about 100 and the spherical harmonic expansion approach as a mathematical method was used. In order to produce the ionospheric total electron content (TEC) based on grid form, we defined spatial resolution of 2.0 degree and 5.0 degree in latitude and longitude, respectively. Two-dimensional TEC maps were constructed within the interval of one hour, and have a high temporal resolution compared to global ionosphere maps which are produced by several analysis centers. As a result, we could detect the sudden increase of TEC by processing GPS observables on 29 October, 2003 when the massive solar flare took place.