• Journal of the Korean earth science society
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• v.41 no.5
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• pp.469-477
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• 2020

Salinity is not only an important variable that determines the density of the ocean but also one of the main parameters representing the global water cycle. Ocean salinity observations have been mainly conducted using ships, Argo floats, and buoys. Since the first satellite salinity was launched in 2009, it is also possible to observe sea surface salinity in the global ocean using satellite salinity data. However, the satellite salinity data contain various errors, it is necessary to validate its accuracy before applying it as research data. In this study, the salinity accuracy between the Soil Moisture Active Passive (SMAP) satellite salinity data and the in-situ salinity data provided by the Ieodo ocean research station was evaluated, and the error characteristics were analyzed from April 2015 to August 2020. As a result, a total of 314 match-up points were produced, and the root mean square error (RMSE) and mean bias of salinity were 1.79 and 0.91 psu, respectively. Overall, the satellite salinity was overestimated compare to the in-situ salinity. Satellite salinity is dependent on various marine environmental factors such as season, sea surface temperature (SST), and wind speed. In summer, the difference between the satellite salinity and the in-situ salinity was less than 0.18 psu. This means that the accuracy of satellite salinity increases at high SST rather than at low SST. This accuracy was affected by the sensitivity of the sensor. Likewise, the error was reduced at wind speeds greater than 5 m s^-1. This study suggests that satellite-derived salinity data should be used in coastal areas for limited use by checking if they are suitable for specific research purposes.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.490-503
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• 2020

Oceanic current and circulation have played an important role as regulators of the earth's energy distribution. The science and earth science textbooks for secondary schools based on the 2015 revised curriculum included a misconception of the seasonal variation of the North Korea Cold Current (NKCC) among the currents around the Korean Peninsula. To analyze this, the contents related to the NKCC were collected in the textbooks of five middle and six high schools, and a questionnaire survey was conducted on 30 middle school science teachers. The survey consisted of questions about whether the textbook mentions the NKCC and whether there is an error in the concept of the temporal variation of the NKCC, and the teachers' free opinions related to the NKCC were collected. The textbooks suggest that the NKCC is strongest in winter, which is not consistent with scientific findings so far. In fact, there is scientific evidence that the NKCC is the strongest in the summer. In this study, the causes and processes of misconceptions were investigated. According to an analysis of the survey, most teachers had an knowledge that the NKCC is stronger in winter. These errors began with a misconception of the terms, which teachers had imprinted on their memory as firm knowledge. These misconceptions originated from the knowledge that teachers themselves acquired from their secondary school years and have long been transferred back to teachers and students without revising the misconceptions of textbooks. This situation is expected to have a seriously recurrent structure that produces students' serious misconceptions in the future. Therefore, this study summarizes existing results on the seasonal variability of the NKCC and suggests the necessity for re-education to improve teachers' professionalism and to eliminate the misconceptions of teachers and students.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.872-881
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• 2002

Student questioning is included in the priority of science literacy, to enable students to solve problems by exploring questions, communicating and constructing knowledge(AAAS, 1989). Also, the essence of student questioning in science lies in its function as a link between thinking and learning. But educators did not pay much attention to students' questioning in Korea. The purpose of this study was to investigate the effects of science question enhancement instruction on students' science questioning level and achievement. Also, this study showed the effects of other variables(logical thinking, science achievement, interest, and gender) on students' science questioning level. The pretest-posttest control group design group design was used. The sample was consisted of 80 second grade middle school students in experimental group(Science question enhancement instruction) and 74 students in control group(Traditional learning). Students in both groups were received identical content instruction on the unit 'Structures and functions of plant'. These groups were treated for 15 hours during 6 weeks. Students' questions were rated using the four levels described by the Middle School Students' Science Question Rating Scale(r= .96,)(Cuccio-Schirripa & Steinner, 2000). Science achievement data were collected using a 17 item multiple choice test(Cronbach ${\alpha}$= .84). To investigate students' logical thinking ability, a abridged GALT(Cronbach ${\alpha}$= .69) was used. Five-way ANOVA, ANCOVA, and multiple regression analysis were used to analyze the results. The results indicated that students who received instruction on researchable questioning outperformed those students who were not instructed on high-order questioning(p< .01). Results of correlations indicated that instruction(r= .640), science achievement(r= .311) and logical thinking ability(r= .212) was significantly and positively related with students' questioning level. But, interest and gender did not show any significant correlation with students' questioning level. Science question enhancement instruction was more effective on science achievement than the traditional instruction(p< .01).

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.221-233
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• 2000

Many investigators have reported difficulties in changing the high school students' misconceptions on mechanics. By one possible solution to this problem, some researchers suggested that the students should be taught mechanics at a younger age to make conceptual changes possible. because as they get older they become less willing to change their ideas. The purpose of this study was to compare the patterns of students' conceptual changes on force by age, to find out whether older students were less ready to change their conceptions than younger students. Individual interviews were carried out with 35 students (average ages 13) in middle school class and 50 students (average ages 17) in high school class near by the middle school. Those students who held the misconcetpion that "motion-implies-force (Impetus conception)" were asked to read a student-centered refutational text (anomalous data). In the immediate and delayed posttest, the types of responses of the students were analyzed to find out the patterns of student's conceptual changes on force by age. In result, first, most of students had impetus conception. Some of the students aged 13 understood the force as terminologies related with everyday experiences, while the students aged 17 understood the force as scientific terminologies. Second, there was no evidence to suggest that conceptual change is more difficult for the students aged 17 than aged 13. Third, the students aged 13 showed diverse responses (plain acceptance, critical acceptance, plain rejection, critical rejection) to the refutational text, while the students aged 17 showed restricted responses (critical acceptance, critical rejection). A month later those students who showed the plain acceptance retrogressed unscientific conceptions, while those students who showed critical acceptance maintained scientific conceptions. We did not find out any evidence to suggest that conceptual change is more difficult for older students. These results need deeper investigation on the nature of the loss of plasticity in comparison with other important variables.

• Journal of The Korean Association For Science Education
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• v.31 no.2
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• pp.225-238
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• 2011

The purpose of this study was to investigate the effects of the instruction with question-creation training, compared with traditional science instructions. The instruction with question-creation training is to give students chances to make questions by themselves based on what they learned before the end of the classes. The four effects of the instruction were studied: students' achievement, metacognition, self-efficacy, and the level of the questions created by the students according to different proficiency levels. Research data was gathered from 65 second grade students at a middle school in Busan. The comparative group was instructed in traditional lecture-type teaching method. The experimental group was instructed with questioncreation training. Students in the experimental group were asked to make 3 questions by themselves and then, to solve their peers' questions about 15 minutes before the end of the classes. Both groups were divided into 3 groups by proficiency level according to the results of last semester's science test. Before the research, a metacognition test and a self-efficacy test were conducted. After the research, an achievement test, a question level test, a metacognition test, and a self-efficacy test were conducted and analyzed by t-test. The research data for question level was analyzed by one-way ANCOVA. The results of this study revealed that question-creation training has a positive effect on student's achievement, metacognition, and self-efficiency. It also showed most of the students have gained an ability to make higher-level questions regardless of their proficiency level due to the increased number of students who made higher-level questions. It also showed that most of the students could gain an ability to make higher-level questions regardless of their proficiency level from the fact that the number of students who made higher-level questions increased in every proficiency level.

• Journal of The Korean Association For Science Education
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• v.38 no.2
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• pp.293-304
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• 2018

In spite of a growing number of recent studies that indicate students are coming to view scientists with more varied images, the stereotypical image of scientists remains in many students' minds. In this study, the authors explore how college students change their perceptions of science and scientists through the use of a documentary that focuses on scientists' daily lives, including laboratory life, and their emotional ups-and-downs. We analyzed 109 college students' essays on perceptions about scientists after watching the documentary. As a result, 64.2% of the college students declared that there was a change in their perception of scientists. The students' new perceptions of science and scientists are as follows: 1) scientists undergo emotional ups-and-downs just like any normal person; 2) scientists experience numerous failures while researching; 3) science does not have a fixed answer and scientists undertake research with creativity; 4) scientists conduct research in collaboration, but also in highly competitive environments; 5) scientists are often frustrated with their socio-economic status. The students' previous perceptions on science and scientists were mainly stereotypical ones that have been reported in previous studies. In addition, of the other college students who did not change their perceptions, the majority declared that they have new perceptions such as 1) - 5). Only a small percentage of students (7.3%) had unchanged stereotypical perceptions. These results are interpreted as that college students relatively easily change their stereotypical images of scientists after watching the documentary but, alternatively, the results can be interpreted that the most stereotypical images of college students are not perceptions that form a deep impression, but rather they are simply depictions of representative images of scientists given from outside sources (e.g. the mass media and school).

• Sleep Medicine and Psychophysiology
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• v.16 no.2
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• pp.65-73
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• 2009

Objectives: The purpose of this study was to assess the clinical and polysomnographic characteristics of Korean patients with obstructive sleep apnea syndrome (OSAS), especially in relation to differences due to age and gender. Methods: All subjects were consecutive patients who were proven to have OSAS with nocturnal polysomnography. They were interviewed with a structured interview format including sociodemographic information, past medical history, medication, and sleep-related history. Simultaneously, they were also given Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) to answer in order to check subjective sleep quality and subjective sleepiness. Results: Mean age of the 308 subjects was $49.5{\pm}$13.3 years, with 77.6% of the subjects being males and 22.4% of the subjects being females. The aging effects on the sleep architecture in Korean OSAS corresponded with normal aging, but with the effect of OSAS itself superimposed, the extent of aging effects was more marked than that of normal aging. The severity of Korean patients of OSAS was not correlated with age. When divided into age subgroups, significant correlation was found between RDI and BMI in patients of each subgroup of those in the 4th to 7th decades. The oldest subgroup (>70 years) described their subjective sleep quality as poorer than any other age subgroups, despite of less subjective drowsiness. The severity of OSAS and the change of sleep architecture of male subjects turned out to be severer than those of female ones. The female/male ratio of the subjects tended to increase with aging. Conclusions: The aging effect on the sleep architecture in Korean OSAS seems to be a mixture of the changes by normal aging and sleep disorder per se. The severity of OSAS was not correlated with age, but highly correlated with BMI. The severity of OSAS and the change of sleep architecture of male patients were severer than those of female ones.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.293-300
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• 2003

This study examined the foraging activities and the Influence of excessive foraging activity by B. ignitus workers on the quality of cherry-tomato fruits in cherry-tomato green-house. The peak time of pollination by B. ignitus worker was recorded at 8:00 and the average of foraging time on each flower was 11.7 secs. The total pollinating time of B. ignitus was 41 mins and 37 secs and its total number of visiting flowers was 195.2. The average time of staying on flowers was 8.8 ${\pm}$5.4 secs when two bumblebees were allowed to pollinate per Pyong (3.954 square yards) in the green house of tomatoes for 24 hours, but it was two times shorter (4.0${\pm}$3.1 secs) compared with that when one bumble-bee was allowed to pollinate per Pyong for one hour. The stamen color of tomato flowers visited by the bumblebee for one hour was brown while the stamen color for 24 hours was dark brown due to the frequent visiting. The average fruit bearing rate of the 4th-6th clusters of tomatoes visited for one hour was 48.9%, which was not significantly different from those allowed to visite for 24 hours. However, the number of seeds of flowers visited for 24 hours was 64.0, which was more than 55.3 seeds of flowers visited for one hour. The weight of fruit was 25.4 g and 24.4 g, respectively. The sweetness was not different significantly between one and 24 hours of visit (P > 0.05). The result revealed that end pro-duct of cherry-tomato was not influenced by over foraging activity of B. ignitus workers on tomato flowers.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.2
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• pp.138-143
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• 2015

Purpose: The aim of this study was to compare the translucency of two different laminate ceramic veneers with and without glazing. Materials and methods: Ten millimeter side square-shaped specimens in 0.3 mm and 0.6 mm thick were fabricated for the following materials with and without glazing (n=80): A1 shade IPS e.maxPress (IEM) and Styleveneers (STV). The color coordinates (CIE $L^*a^*b^*$) of the specimens were measured with a colorimeter. The Translucency parameter (TP) was calculated from the color difference of the material on a black versus a white background. For comparisons between materials and between the 'not glazed' and 'glazed' groups, unpaired t-test was used to analyze the data (P=.05). Results: The TP ($Mean{\pm}SD$) of 'not-glazed' and 'glazed' group of IEM specimens at 0.3 mm thickness were $45.99{\pm}3.00$ and $49.53{\pm}2.28$ and the TP at 0.6 mm thickness were $32.82{\pm}2.59$ and $43.02{\pm}0.98$, respectively. Likewise, the TP of 'not-glazed' and 'glazed' group of STV specimens at 0.3 mm thickness were $47.03{\pm}3.65$ and $50.95{\pm}3.05$ and the TP at 0.6 mm thickness group were $34.48{\pm}1.28$ and $43.39{\pm}1.20$, respectively. As the glazing of ceramic veneer differed, the TP of each ceramic veneer showed statistically significant difference. But, the result between the products was not statistically different. Conclusion: Within the limitations of this study, we are concluded that the glazing process changed translucency of laminate ceramic veneers and the TP would not be affected by products.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.456-468
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• 2008

This study was performed to evaluate the quality of newly offered dentin bonding system($AdheSE^{(R)}$ One) by comparing the degree of microleakage measured with those of several conventional adhesive materials(AQ Bond Plus and $Adper^{TM}$ Single Bond 2). The quality of hybrid layer and resin tags was analyzed by observing restoration/ tooth interface under SEM. All-in-one system is in the limelight for having advantage of reducing chair time of children with difficult behavior pattern. Therefore the possibility of clinical application of All-in-one system was evaluated. The results obtained are as follows; 1. At the enamel margin, group II(AQ Bond Plus) showed the highest value of microleakage, and the other groups showed decreased value in order of group III($AdheSE^{(R)}$ One) and I($Adper^{TM}$ Single Bond 2). There was statistically significant difference between group II and the others(p<0.05), and no statistical difference was found between group I and III. 2. At the dentin margin, microleakage value was increased in order of group II, I, III and significant difference between all groups(p<0.05). 3. In group I and III, microleakage value measured at the enamel margin was significantly lower than that seen at the dentin margin(p<0.05), and there was no statistical difference in group II. 4. Resin tags observed under SEM were very weak and tangled in group II and III while the strong and thick tags were observed in group I. In conclusion, careful case selection and accurate clinical application is recommended in using AQ Bond Plus and $AdheSE^{(R)}$ One, giving consideration of the results showing its higher microleakage and weaker strength than $Adper^{TM}$ Single Bond 2.