• Communications of Mathematical Education
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• v.24 no.3
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• pp.543-562
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• 2010

The purpose of this thesis is to analyze the error happening in the process of solving the simultaneous inequality with two unknown qualities and to propose the correct teaching method. We first introduce a problem about the simultaneous inequality with two unknown qualities. And we will see the solution which a student offers. Finally we propose the correct teaching method by analyzing the error happening in the process of solving the simultaneous inequality with two unknown qualities. The cause of the error are a wrong conception which started with the process of solving the simultaneous equality with two unknown qualities and an insufficient curriculum in connection with the simultaneous inequality with two unknown qualities. Especially we can find out the problem that the students don't look the interrelation between two valuables when they solve the simultaneous inequality with two unknown qualities. Therefore we insist that we must teach students looking the interrelation between two valuables when they solve the simultaneous inequality with two unknown qualities.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.131-138
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• 2000

We compared the study of refractive error of the eyes done in 1998 with that reported three years ago at any high school in the north Kyungki. From the these data, the distribution of ammetropia was investigated. The study of refractive error for high school students was also compared with those reported before for the Adults and the middle school student. When the refractive error is refered to spherical equivalent, the 40.6% of the whole students examined above had emmetropia and the other part of them(59.4%) turned out to be ammetropia which is classified to 46.4% belonged to myopia and 13.0% belonged to hyperpia. The ratio of emmetropia for the students in 1998 is 4.4% lower, and the ratio of hyperopia is 4.3% lower, but the ratio of myopia for the students in 1998 is 8.7% higher than that for the student in 1995. In the kind of refracive error, it is classified that a simple myopia is shown to highest ratio as a 23.6% of 6143 eyes examined, a compound myopic astigmatism to the next high ratio as a 17.4%, a simple myopic astigmatism as 10.9%, a simple hyperopic astigmatism as 9.8%, a simple astigmatism as 7.1%, a compound hyperopic astigmatism as 2.2%, a mixed astigmatism as a 1.8%, respectively. The percentage of an astigmatism is a 69.6% of total eyes examined if Cyl-0.25 Dptr is included to an astigmatism. On the other hand. The percentage of an astigmatism is a 45.0% of total eyes examined if Cyl-0.25 Dptr is excluded to an astigmatism. In the kind of astigmatism, the number of students had an astigmatism with the rule is about 5.6 times than that of astigmatism against the rule. From the result of comparison the right eye with the left eye, the right eye of the students had more a myopic refractive error than the left eye, which is same as adults' case.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.278-286
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• 2008

Many studies regarding Casein phosphopeptides-amorphous calcium phosphate(CPP-ACP) have demonstrated the remineralization ability on the demineralized enamel surface. A question is still remained that how deep can the calcium (Ca) and phosphorus (P) ions supplied by the CPP-ACP paste penetrate into the enamel subsurface. The aims of this study were to measure the penetrating depth of Ca and P ions in the demineralized human enamel in vitro, and were to determine the amount and depth of Ca and P ions according to the duration. The amount and depth of Ca and P ions were measured by microscopic observation with Field Emission Scanning Electron Microscopy (FE-SEM; LEO SUPRA 55, Carl Zeiss, Germany) and Energy Dispersive X-ray Spectrometer (EDS; GENESIS 2000, EDAX, USA: Linescan of Calcium and Phosphorus). Freshly extracted four human 1st premolars were obtained from the Dept. of Pediatric Dent., Kyung Hee Univ. Buccal surfaces of the 1st premolars were covered with nail varnish to form a window on the middle third of buccal surface. All of the teeth with enamel windows were immersed in a solution of 0.1 M lactic acid, Carbopol C907 (carboxypolymethylene BF Goodrich, Cleveland, OH, USA) at pH 4.8, and then incubated for 7 days. Each tooth crown was sawn in half through the midline of buccal window along the long axis of premolar. The four blocks of premolars were immersed in a 10-times diluted solution of CPP-ACP paste (Tooth Mousse, GC Corp., Tokyo, Japan) for 1, 2, 3 and 5 weeks while the rests were immersed in a placebo solution (distilled water) for the same duration. Each specimen was embedded in epoxy resin, and was sectioned perpendicular to the window, using a water-cooled diamond blade saw. The spectrum density indices of Ca and P were measured in the sound, de- and remineralized enamels by FE-SEM and EDS. The Student's t test was performed to compare the Spectrum Density Indices (SDI) of sound, re-and demineralized enamels, and to compare the differences among the durations. Followings are the conclusion : 1. The penetration depth of the remineralizing ions (Ca & P) of CPP-ACP paste is related to the depth of demineralized enamel (approximately $1050{\sim}1350{\mu}m$). It is revealed that the penetration depth of both ions reaches full thickness of decalcification and even slightly into the sound enamel. 2. The Ca & P levels of remineralized enamels in 1, 2 weeks were significantly higher than those of the sound enamels (p<0.05). 3. No statistically significant difference of Ca & P levels was found in relation with the increasing duration of remineralization (p>0.05).

• The Korean Journal of Archival Studies
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• no.51
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• pp.89-132
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• 2017

The presidential records reflect the era of the times, and it has valuable evidence to support the administrative transparency and accountability of government operations. People's interest in the presidential records increased in response to its recent leak. The presidential archives were moved to Sejong in line with its desire to provide public-friendly services. This study will help users access the archives and utilize archiving information. The Ministry of Education introduced the free learning semester, which all middle schools have began conducting since 2016. The free learning semester provides an environment where education can be provided by external organizations. As middle school students are still unfamiliar with archives, the free learning semester provides a good environment for accessing archives and records. Although it serves as an opportunity to publicize archives, existing related studies are insufficient. This study aims to develop the free learning semester program using the presidential archives and records for middle school students during the free learning semester based on the analysis of the domestic and foreign archives education program. This study shows a development of the education program using presidential archives and records through literature research, domestic and foreign case analysis, and expert interview. First, through literature research, this research understood the definition of the free learning semester as well as its types. In addition, this research identified the four types of the free learning semester education program that can be linked to the presidential archives. Second, through website analysis and the information disclosure system, this research investigated domestic and foreign cases of the education program. A total of 46 education programs of institutions were analyzed, focusing on student-led education programs in the foreign archives as well as the education programs of the free learning semester in domestic libraries and archives. Third, based on these results, This study proposed four types of free learning semester education programs using the presidential archives and records, and provided concrete examples.

• Korean Journal of Health Education and Promotion
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• v.18 no.3
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• pp.133-162
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• 2001

Unexpected accidents in school has been gradually increased every year, and student's mistaken was the first reason of the accident. To preventing the students from Unexpected accidents in school, safety education is more important than having strong facilities to have much more strong protecting forces for the accidents. Therefore, systematic education of safety is needed most of all, and especially, strengthening safety education in school is needed. Hereby, this study is aimed at investigating and analysing the actual condition and demand of safety education. It also conducted a survey with the target of 1,255 students in the second grade of high school in Seoul from April 20 to May 19, and the result of this study is as follows. 1. In the general features of the subject of the survey, boy students and girl students occupied 50.8％ and 49.2％ each, and boys' high school (34.3％), girls' high school(32.2％) and co-ed(33.5％) participated in balance. In the location, north from Han river occupied 54.6％, south were 45.2％. 2. According to the status of experiencing an accident, boys were more experienced then girls(p〈0.05). From the section, home accident(56.8％) occupied most followed by school accident, traffic accident, sports accident and poisoning. The accident happening most often in detailed category is sports accident such as basket ball, foot ball and dodge ball. The actual condition of the subject's using a school health facility shows that boys students use it more often than girl students(p〈0.01) 3. In attitude toward safety, the subject showed lower interest in safety issues than other social issues. But attitude in seriality of safety problems were high. Also, they responded ‘individual citizen’(63.1％) as the one who should make efforts for safety. Regarding knowledge of preventing safety accidents in attitude toward individual safety, 42.2％ answered ‘they know a little’ and 32.6％ of respondents say ‘they do not know’. To a question of the degree of the subject's following safety rules, 36.4％ were answered ‘keeping’ and the group using a school health facility shows more ‘keeping’ the others(p〈0.05). 4. To a question of asking if they have experienced safety education, 51.2％ answered ‘yes’. Teachers who mainly take care of safety education are answered as training teacher(48.7％). As for education time, training class(51.3％) is said to have safety education most followed by health-related event and PE(Physical Education). Frequency of education shows once or twice a session (62.8％) most often, but in case of co-ed school, 5-7times a session or more(20.1％) are being practiced. Looking at education time, 1-2 hour(s)(22.1％) or for a short time(22.1％) during class are being practiced. As an education method, instruction(43.8％) and video education(32.5％) are being practiced, and when it comes to education evaluation method, ‘not practiced’(70.0％) answered. To the question if they are satisfied with school safety education, they answered more ‘no(43.1％)’ than ‘yes(6.7％)’, and the reason is that safety education class is just for formality's sake, and the fact they already know is being repeated. The contents of safety education is composed of school safety, home safety, and first aid. 5. It is turned out that 56.5％ of the total boy students and 61.1％ of the total girl students recognize the necessity of safety education. To the question if safety education is needed in an elementary and middle education course, 46.4％ of the subject answer answered' it's necessary'. The most reason for their answers are ‘safety education is directly related to life’. 6. Regarding the requested time of safety education is ‘one hour a week’ by 55.9％. For safety education, safety education teachers(38.7％) are answered to be the most proper. As a request for safety education, video education is answered to be the most appropriate(30.6％), followed by practical skills, lecture and discussion(p〈0.05). Demand of educational evaluation, practical skills, interview and observation are answered to be needed. To the question if they want to participate in the way of demanded safety education, 41.9％ of respondents answer ‘have a mind to participate in’ (41.9％). To benefits followed by completing safety education, 72.0％ of respondents answer ‘agree’, and 24.7％ ‘do not agree’, which means lout 4 disagrees with completing safety education. 7. Looking at demand of safety education according to the features of the subject, ‘our position for the person who has handicapped’ was answer to the most.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.2
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• pp.147-161
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• 2020

In order to help elementary students understand the astronomical unit in depth, this study applied backward design 2.0 to check the effect on students' science academic achievement, performance evaluation, and science class satisfaction. As a result of the study, there was no statistically significant difference in the science achievement test, but the average score of the experimental group has improved. As a result of the performance evaluation test, there was a statistically significant difference because the feedback was well provided through the process-focused assessment and it helped in-depth understanding. As a result of the science class satisfaction test, there was a statistically significant difference in the areas of science curriculum and peer relation except for the science teacher area. This is because a differentiated science curriculum was designed through analysis of achievement standards, and various teaching methods of student-centered were implemented to reach achievement standards. We hope this study will focus on the impact of backward design 2.0 on learners in elementary science classes and help find ways to effectively apply backward design 2.0 in the field.

• Communications of Mathematical Education
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• v.30 no.3
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• pp.375-392
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• 2016

The purpose of this study is to provide a philosophical reflection on mathematical process consistently emphasized in our curriculum and to stress the importance of sharing creativity and its applicability to the mathematical process with the value of sharing and participation. For this purpose, we describe five stages of changing process in a peer mentoring teaching method conducted by a teacher who taught this method for 17 years with the goal of sharing creativity and examine components of mathematical process and their impact on it in each stage based on learning environment, learning process, and assessment. Results suggest that six principles should be underlined and considered for students to be actively involved in mathematical process. After analyzing changes in the five stages of the peer mentoring teaching method, the five principles scrutinized in mathematical process are the principles of continuous interactivity, contextual dependence, bidirectional development, teacher capability, and student participation. On the basis of these five principles, the principle of cooperative creativity is extracted from effective changes of mathematical process as a guiding force.

• Journal of Korean Home Economics Education Association
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• v.23 no.4
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• pp.125-141
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• 2011

The purpose of this study is to investigate Home Economics(HE) teachers' perception of Home Economics curriculum perspective and their instructional culture, and to find out correlations between them. 210 questionnaires were used for analysis. The results are as follows. First, our research showed that the preferences of HE teachers with respect to curriculum perspectives were in the order of the interpretive, emancipatory, and technical perspectives. However, there was no consistency among findings in the preferences for the sub-elements of a curriculum. Second, our results indicated that HE teachers performed their role affirmatively in terms of instructional culture such as the 'cooperation between teachers', the 'class focused on student', and the 'learning materials preparation'. Third, there was a statistically significant difference in five elements such as the 'cooperation among teachers' between the HE teachers' curriculum perspectives and their instructional culture. Fourth, there was a statistically significant difference in the 4 factors of 'instructional culture' between the teacher group whose curriculum preference was clear and those group whose curriculum preferences was vague.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.303-311
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• 2011

This study aimed to identify success factors of smoking cessation for 6 months in Adolescent smokers. Data were collected from January to December, 2008. The 925 adolescent smokers were registered smoking cessation clinic at public health center in Incheon. Data(demographic, smoking, smoking cessation) were analyzed by logistic regression. Major factors are attempting to quit smoking(no trial, OR=9.48), alcohol drinking(yes, OR=4.61), information source for registration(family, friends's ask, OR=3.94), cessation methods(cognitive+behavior+ nicotine alternative therapy, OR=2.45), gender(male, OR=1.78), grade in school(high schooler, OR=1.65), expiration CO concentration (OR=0.95), and nicotine dependency(OR=0.76). Therefore, smoking cessation policy for adolescence should be emphasized on smoking prevention as well as smoking cessation. We have to help the adolescent to succeed in smoking cessation when they attempt to quit smoking at first time. Female student smokers and middle school smokers should be given advice for smoking cessation motives and more times of counselling for smoking cessation. If adolescent smokers have high expiration CO concentration and high nicotine dependency, they should not only take cognitive-behavior therapy but also nicotine alternative therapy.

• Journal of Educational Research in Mathematics
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• v.17 no.1
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• pp.67-90
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• 2007

The purpose of this study is to understand students' thinking process in the algebra problem solving, on the base of the works of Vinner(1997a, 1997b). Thus, two middle school students were evaluated in this case study to examine how they think to solve algebra word problems. The following question was considered to analyze the thinking process from the similarity-based perspective by focusing on the process of solving algebra word problems; What is the relationship between similarity and the characteristics of thinking process at the time of successful and unsuccessful problem solving? The following results were obtained by analyzing the success or failure in problem solving based on the characteristics of thinking process and similarity composition. Successful problem solving can be based on pseudo-analytical thought and analytical thought. The former is the rule applied in the process of applying closed formulas that is constructed structural similarity not related with the situations described in the text. The latter means that control and correction occurred in all stages of problem solution. The knowledge needed for solutions was applied with the formulation of open-end formulas that is constructed structural similarity in which memory and modification with the related principles or concepts. In conclusion, the student's perception on the principles involved in a solution is very important in solving algebraic word problems.