• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1229-1243
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• 1997

The purpose of this study were to :(a) investigate meal costs, plate waste costs, and advantages/disadvantages of conventional /commissary foodservices and (b) compare the effectiveness of commissary foodservice systems with that of conventional systems. Questionnaires were developed and mailed to 136 schools in Kyonggi-do. A total of 106 questionnaires were usable, resulting in a 77.9% response rate. Teacher's teaching of good food habits and students satisfaction with school foodservices were surveyed in three schools from each system. Moreover, plate waste was measured to express cost and benefit in currency. Data were analyzed using the SAS package for description analysis, t-test, $\chi$$^2$ test, ANOVA, and the Vilcoxon rank sum test. Approximately seventy percent of 294schools in Kyonggi-do were operating commissary systems and most of them were of the rural (reduced paid) type. The number of meals served varied significantly between types of foodservice. The results of this study indicated that average food , labor utility , and supply costs were saved in the commissary system and that the total meal cost/person for a day was 1218.7 won compared to 1452.4 won in the conventional system. Though total meal costs were saved in the commissary system, dietitians had difficulties cooperating with school foodservice committees and supporters associations, especially in satellites of the commissary system. In addition, dietitians and teachers in the commissary system did not carry out teaching activities on good food habits to students as often as in the conventional system. Other problems that dietitians recognized in the commissary system were difficulties in training employees and parents for portion control and serving relatively simple menus. Students, as customers of school foodservices, are very important for system evaluation . Students in the commissary system scored of food itself , cleanliness of tableware, waiting time, quantity of meal and food temperature significantly lower than students in the conventional system. Moreover , the rate of plate waste was 20.5% in the commissary system as compared to 3.3% in the conventional system. Cost-effectiveness (saving 233.7won/person/day) is the main benefit of the commissary system. However , because of lower satisfaction scores and a highest plate waste rate, 201.9won/ person were wasted in the commissary system. The results of this study suggest that increasing the number of meals served within a commissary system might maximize the efficiency of the system, but increasing the number of satellites is not recommended because it might be out of dietitians control in many aspects.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.564-577
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• 1999

The purpose of this study is to help an improvement of conceptional learning about the properties of gas based on molecular kinetics for secondary school students and to help an improvement of teaching method for reducing misconceptions regarding the molecular kinetics in gas phase for teachers. The subjects of this study were l00 students of 9th grade and 150 students of 11th grade students. The results showed that students had various misconceptions about the properties of gas. The major misconceptions are as follows. First, the energy is released due to the collision of the molecules, and also the direction of action of pressure is related to the direction of gravity. Second, as molecule is heated, the size of molecule is increased, and the molecule is more active because the number of moIecules is increased. Third, the pressure is reduced because of decreasing the temperature at the higher altitude and the pressure of gas molecuIes is inversely proportional to the collision number of gas molecules. Forth, the numbers of molecules of two different molecules in two same containers differ because the size of molecules differ each other. The results suggest that these problems ought to be addressed in chemistry textbooks and in the classroom teaching of chemistry. If teachers are more aware of students' misconceptions they wilI be better able to remove them.

• Journal of Science Education
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• v.32 no.2
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• pp.71-86
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• 2008

The purpose of this study was to apply After-school programs related to sub-chapter 'The Change of Weather', and thereby to investigate the effect of After-school program on science-related attitude and learning achievement of students, and interaction between treatment methods and students' learning ability. The subjects of study consisted of 2nd grade students of sixty four students in high school. Sixty four students were divided into two categories by experimental and control groups on the basis of midterm examination before teaching treatment. The experimental groups have received four After-school programs including making models of a weather front, measurement of wind, measurement of temperature and the dew point, making a three-dimensional weather chart which were developed by researcher for six times. The control groups have received the instruction through the conventional teaching methods. Seventy questions within seven frameworks of TOSRA have been used in this study as an evaluation instrument of science-related attitude. Learning achievement has been evaluated using an instrument developed by researcher. The scores of both pre-test and post-test were estimated by ANCOVA. The results of this study can be summarized as follows. (1) After-school programs were more effective in progressing the three categories of science related attitude of high school students i.e. pleasure of science class(p<.05), reception of scientific attitude(p<.01), attitude about a science research(p<.05) than conventional teaching methods. (2) Experimental groups showed statistically significant improvement on learning achievement than control groups(p<.05). (3) The effect of treatment methods on students' learning ability has been improved in experimental groups more positively than control groups(p<.05). High level students in experimental groups showed significant improvement on learning achievement than low level students according to the representing profile plot. But there were no significant interaction between treatment methods and students' learning ability(p>.05) In conclusion, the After-school programs have positive effect on the improvement of science related attitude and learning achievement.

• Journal of Korean Elementary Science Education
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• v.36 no.1
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• pp.1-15
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• 2017

The purpose of this study is to analyze the problems of land and sea breeze model experiment that has presented in $5^{th}$ grade curriculum in chapter "Weather and our lives" and makes better model simulation so that learners can have better and more effective way to study it. To survey the opinions from dedicated teachers about land and sea breeze model experiment, we produced the survey through interview with science exclusive teacher from M elementary school. An elementary science education expert, 3 men of science EdD modified and complemented survey and started Delphi survey to 12 science teachers who have career teaching more than 3 years. The problems found in this survey were 'one heat bulb, short heating time, small temperature difference of water and sand, lack of class time, empty space between sand and water, back of transparent boxes, little amount of scent and the location of the it' etc. But the most of all, it is hard to see the successful result of the experiment. Based on these kinds of investigations, and lots of trial and error, redesigned the new model experiment that has the most similarity to the real one and high probability of success. According to this, it was able to see the smoke forms horizontal movement along the sand and the smoke goes in one circulation cycle. through this experiment, we made a conclusion that although those scientific experiments in textbook were developed through lots of considerations of expert, to consider the aspect of consumer, it needs to reach the educational agreement about simulation experiment so that It can lead to successful experiment and high quality education.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.775-788
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• 2007

This study was aimed to understand the structures of preservice secondary school teachers' alternative conceptions on radioactive isotopes in the interior of earth. The structure of their conceptions were analyzed by the suggestions of Niaz (1988) based on the Lakatosian frameworks. The survey was carried out on a group of seventeen students who were major in science education. The research method was open-ended written questionnaire. The results of this study show that students had apparent alternative conceptions. The high temperature and pressure' explanation for radioactive decay in earth's interior had most import effects on their alternative conceptions. It was also intended to survey their conceptional change by our teaching strategies of the philosophy of science in order to construct science concepts.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.64-74
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• 1993

The chlorination of the titanium slag from titaniferrous magnetite by the arc-smelting in a fluidized bed reactor was investigated to produce $TiCl_4$ from domestic titaniferrous magnetite. The optimum conditions are as follows : reaction temperature; $950^{\circ}C$, reaction time; 90min, $Cl_2$ gas velocity; 3cm/sec, and petroleum coke-to-titanium slag weight ratio; 0.18. Also the mean diameter of titanium slag and petroleum coke was $44.6{\mu}m$ and $67.9{\mu}m$ respectively. Under these conditions 97.07% of Ti component in the titanium slag was chlorinated and the purity of $TiCl_4$ from this chlorination was 96.2%.

• Journal of the Korean Institute of Educational Facilities
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• v.25 no.4
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• pp.19-30
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• 2018

The school classroom is a common living place where students spend 7 to 14 hours a day to prepare for their careers. Therefore, if the ventilation of the classroom is not properly performed, it may lead to the deterioration of learning ability due to the unclear air. The concentration of carbon dioxide in the classroom is reported to be high, and the increase in carbon dioxide concentration has a negative effect on the learner's academic performance. In this context, the purpose of this study is to propose a methodology for intelligent and responsive window opening-closing operation process that can reduce the concentration of $CO_2$ in the classroom in order to build a support space that can create an effective teaching-learning environment for adolescents. The specific objectives are as follows. First of all, we define the concept of window opening-closing operation. Secondly, twe develop the operation process of window opening-closing. Thirdly, we develop an algorithm for real-time window opening and closing (process) (Window Opening-Closing Operation Process). Finally, we verify the intelligent responsive window opening-closing operation process through developing examples of window opening-closing operation process using the parametric design program. This study is a preliminary study to develop algorithms necessary for window opening-closing operation. Based on the first-order algorithm, We simulated window opening-closing operations according to a hypothetical scenario. As a result, This study can show that the window is open and close depending on the $CO_2$ concentration, but the $CO_2$ concentration in the room is higher than outdoors. Consequentially, we suggest that it is necessary to develop an algorithm to supplement these results because window is often not working when the temperature difference between indoor and outdoor in winter is large.

• Journal of the Korea Convergence Society
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• v.12 no.10
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• pp.203-210
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• 2021

This study was conducted to develop a convergence education program using smart farms with both input data(temperature, humidity, etc.) and output data(vegetables, fruits, etc.) that are easily accessible in everyday life so that elementary school students can intuitively and easily understand the principles of artificial intelligence(AI) learning. In order to develop this program, we conducted a prior study analysis of a horticulture, software, robot units in the 2015 Practical Arts curriculum and artificial intelligence education. Based on this, 13 components and 16 achievement criteria were selected, and AI programs of 4 sessions(a total of 8 hours). This program can be used as a reference when developing various teaching materials for artificial intelligence education in the future.

• Journal of Korean Elementary Science Education
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• v.37 no.4
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• pp.363-371
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• 2018

The purpose of this study was to analyze the effects of wearing lab coats on science-related attitudes of elementary school students in science learning. In addition, we analyzed the effects of wearing lab coats on perceptions of the authenticity of school science activities and the necessity of wearing lab coats. Samples of the study were composed of 4 classes of 92 fifth graders in Seoul, Korea. Unit of 'Temperature and Heat' was selected as a object of the research. The major results of the study are as follows. First, for the independent t-test of science-related attitudes, a statistically significant difference between the experimental group and the comparative group was found. Second, 9 students (9.78%) were more than 1SD above the average of the difference between the results of pre and post. Seven of them were experimental group students and two were comparative group students. Third, there was a statistically significant difference between the comparison group and the experimental group as a result of the perception test of the similarity of the scientific activity of the elementary school students and the scientific activity of the scientists. Fourth, there was no statistically significant difference between the comparison group and the experimental group as a result of the perception test of the necessity of wearing a lab coat. Based on these findings of this study, implications for science education research and teaching and learning at school are discussed.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.13-35
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• 2023

Ocean currents play the most important role in causing and controlling global climate change. The water depth of the Yellow Sea is very shallow compared to the East Sea, and the circulation and currents of seawater are quite complicated owing to the influence of various wind fields, ocean currents, and river discharge with low-salinity seawater. The Yellow Sea Warm Current (YSWC) is one of the most representative currents of the Yellow Sea in winter and is closely related to the weather of the southwest coast of the Korean Peninsula, so it needs to be treated as important in secondary-school textbooks. Based on the 2015 revised national educational curriculum, secondary-school science and earth science textbooks were analyzed for content related to the YSWC. In addition, a questionnaire survey of secondary-school science teachers was conducted to investigate their perceptions of the temporal variability of ocean currents. Most teachers appeared to have the incorrect knowledge that the YSWC moves north all year round to the west coast of the Korean Peninsula and is strong in the summer like a general warm current. The YSWC does not have strong seasonal variability in current strength, unlike the North Korean Cold Current (NKCC), but does not exist all year round and appears only in winter. These errors in teachers' subject knowledge had a background similar to why they had a misconception that the NKCC was strong in winter. Therefore, errors in textbook contents on the YSWC were analyzed and presented. In addition, to develop students' and teachers' data literacy, class materials on the YSWC that can be used in inquiry activities were developed. A graphical user interface (GUI) program that can visualize the sea surface temperature of the Yellow Sea was introduced, and a program displaying the spatial distribution of water temperature and salinity was developed using World Ocean Atlas (WOA) 2018 oceanic in-situ measurements of water temperature and salinity data and ocean numerical model reanalysis field data. This data visualization materials using oceanic data is expected to improve teachers' misunderstandings and serve as an opportunity to cultivate both students and teachers' ocean and data literacy.