• Journal of the Korean Society of Earth Science Education
• /
• v.9 no.3
• /
• pp.323-340
• /
• 2016

The purpose of this study is to investigate the effect of observing material on the phase change of moon considering the orbits of earth and moon for elementary school students. For this study, the material which shows the orbit of moon tilted at $5^{\circ}$ with the orbit of earth is developed. 110 6th grade students in an elementary school are sampled. They are divided into the experimental group and the control group. The lessons using the material developed in this study are implemented to the experimental group, and the lessons using the material proposed in ordinary textbook are implemented to the control group. The pre, post, delayed concept tests on the phase change of moon are administered to the students of the experimental group and the control group, and semi-structured interviews are conducted for each concept level. According to students' responses, the concept levels are divided into 'Phase recognition', 'Space viewpoint', 'Earth viewpoint', and 'No recognition'. The experimental group and the control group are homogeneous in the pre-test. The result of this study shows that the experimental group gains significantly more scores than the control group in the post and delayed tests. Also, in the post and delayed tests, more students of the experimental group are in the highest level 'Phase recognition' than the control group. Finally, students of the experimental group who were in the 'Phase recognition' and 'Space viewpoint' explain more scientifically than the students of the control group. Therefore the results of this study show that the observing material on the phase change of moon considering the orbits of earth and moon is effective.

• Informatization Policy
• /
• v.19 no.4
• /
• pp.46-62
• /
• 2012

This research intends to find factors to analyze users, non-users, and the relation between how many sites people use and the users' tendencies, in regards of social network services such as Facebook, Twitter, and Cyworld. The major results are as follows: firstly, the user group seems to be composed of people who are younger, have higher self-efficacy, and use smartphones, compared to the non-user group. Secondly, a single-site user group has lower motivation of 'expert search and expression' and a lower degree of personal tendency of innovation (novelty seeking and self-efficacy), compared to multiple-site user group. Thirdly, foreign SNS user groups have a higher degree of personal tendency of innovation and motivation of 'experts search and expression' than the Cyworld user group. On the other hand, the Cyworld user group seems to be affected by reference group in their use, while they have high motivation of 'connection'. In conclusion, there were significant relationships between personality and multiple SNS uses. Also, Cyworld users tended to use it for maintaining established relationships.

• Korean Journal of Plant Resources
• /
• v.24 no.1
• /
• pp.69-75
• /
• 2011

This study was conducted to investigate the variation of cone, seed and germination characteristics among populations and among individuals within populations of Picea jezoensis(Siebold & Zuccarini) Carriere distributed in Korea. Cone collected from 25 trees in two natural populations(Mt. Jiri and Mt. Dokyu) and their thirteen cone and seed characteristics as well as three germination behaviors were analyzed. Statistical analysis showed significant differences among populations and among individuals within populations in 9 traits except for seed breadth, seed weight, index of seed wing and mean germination time. Generally, morphological variation of cone and seed wings from Mt. Jiri population has smaller and longer than those of Mt. Dokyu population. Percentage of sound seeds and Tetrazolium test from Mt. Jiri population showed 1.79 and 1.87 higher values than Mt. Dokyu population, respectively. The maximum germination percentage was obtained at the optimum temperature of $20^{\circ}C$ and in this case, mean germination time and germination rate showed 7.5 days and 2.9 ea./day, respectively. In seed germination behaviors, percentage(40.7%) and rate(0.90 ea./day) of germination in Mt. Jiri population were more higher and faster than those of Mt. Dokyu population(17.7%, 0.37 ea./day). According to correlation analysis, P. jezoensis populations with small restricted distribution may have been reduced because seed qualities were correlated with increased levels of inbreeding and disproportion flowering.

• Journal of Digital Convergence
• /
• v.18 no.7
• /
• pp.411-419
• /
• 2020

This study was conducted to prove the effectiveness of home-linked indirect smoking prevention education in early childhood in improving the awareness, skills, attitudes and willingness to protect themselves from smoking. 208 5-year-old children were recruited from three kindergartens located in Seoul and Gyeonggi-do. Children in the experimental group received home-linked indirect smoking prevention education. Children in the comparative group, received indirect smoking prevention education in kindergarten. Children in the control group received general health education. The results revealed that all groups showed significant differences between pretest and posttest in awareness of second-smoke, attitudes and willingness to stop smoking. However, the skills to protect oneself from second-smoke showed a significant difference in the experimental group and the comparative group. The values of changes among the groups showed high increases in the order of experimental, comparative, and control groups. This shows that home-linked education had considerable positive effects on indirect smoking prevention.

• Korean Journal of Environment and Ecology
• /
• v.26 no.4
• /
• pp.475-483
• /
• 2012

Tribolodon hakonensis(Cypriniformes; Leuciscinae) is anadromous; they are born in freshwater, migrate back to the ocean, then return to their home stream for spawning from mid-March to early-June. Here, five microsatellites were used to assess the level of gene flow among T. hakonensis populations from the Samcheok-Oship Stream, South Korea. The frequencies of dominant alleles across several loci differed between down-and upstream populations divided by several weirs, and pairwise multilocus $F_{ST}$ estimate was significantly high(0.083). However, there were no signs of any loss of genetic variation in the upstream population. Assignment tests of individuals in admixture model(K=2) to a set of baseline samples showed fairly correct assignment to each cluster; all of upstream individuals sere included in the first cluster, while the majority of downstream individuals(65%) comprise the second cluster. These results indicate reduced gene flow between up- and downstream populations but allowing passive downstream drift. It is likely that man-made structures might at least partially be a factor for creating and consolidating the current distribution patterns of genetic variation among T. hakonensis populations in the Samcheok-Oship Stream. This information will assist governing agencies in making informed decisions regarding conservation of anadromous fishes in Korean drainage systems.

• Korean Journal of Ichthyology
• /
• v.21 no.2
• /
• pp.76-80
• /
• 2009

Genetic diversity and genetic structure within the Geum River and Mankyung River populations of the Korean endangered Black shinner (Pseudopungtungia nigra) were assessed by amplified fragment length polymorphism (AFLP). AFLP analysis using five primer combinations generated 447 AFLP bands with 64.1% polymorphism (Geum River 74.6% and Mankyung River 53.6%). The heterozygosities within the two populations were calculated to be 0.170 and 0.104, respectively. Their average genetic diversities are 0.240 and 0.147, respectively. The pairwise Fst value (0.150) indicated distinct genetic differentiation between the two populations. A UPGMA dendrogram based on genetic distance among the individuals revealed a division corresponding to geographical regions, with low genetic variation within the Mankyung River population, and low genetic distance (0.026) between the two populations. Consequently, the two populations may have the same genetic origin The Geum River population will be more suitable than the Mankyung River population for conservation plans to increase the population sizes. Genetic and habitat management will be necessary for the Mankyung River population.

• Journal of the Korean School Mathematics Society
• /
• v.22 no.2
• /
• pp.163-182
• /
• 2019

The purpose of this study is to investigate the effects of educational context variables on achievement and interest in mathematics in high and low achieving students in Korea. Students participated in TIMSS 2015 in Korea were divided into two groups according to their achievement in mathematics. And the effects of educational context variables on achievement and interest in mathematics were analyzed in each group using the Hierarchical Linear Model(HLM). Main findings of this study are as follows. First, variables which influence achievement also influence interest but any variables which influence interest don't influence achievement in upper-group students. Number of Books and Students' Perceived Mathematics Lessons have strong influence on achievement and interest in both fourth and eighth grade students. Second, variables which influence achievement or interest in mathematics in lower-group also influence achievement or interest in mathematics in upper-group students. But any variables which influence achievement or interest in upper-group students don't influence achievement or interest in lower-group students. For examples, Parents' Education, Students' Perceived Mathematics Lessons have effects on upper-group students' achievement. Number of Books, Home Learning Environment, and Numeracy Activities Before School have significant effects on the achievement of fourth grade students. Students' Perceived Mathematics Lessons is the variable that influence on the interest of both fourth grade and eighth grade students. This study suggests the ways to improve mathematics teaching and learning based on these results.

• 한국노년학
• /
• v.28 no.4
• /
• pp.1089-1111
• /
• 2008

The purpose of this study was to research the effects of socio-demographic factors and values in each group on satisfaction with life by categorizing the activity types of the elderly into volunteer work and economic activities. The subjects of this study were 60 years an old higher. The questionnaires were categorized depending on activity types and collected. The voluntary work group consisted of 201 people (76 males, 36.8% and 125 females, 62.2%), The economic activity group consisted of 219 people (127 males, 58.0% and 92 females, 42.0%). The SPSS 14.0 Windows program was used to analyze data. Frequency, average, standard deviation, factor analysis, Pearson correlation coefficient, t-test, One-Way ANOVA analysis, and hierarchical multiple linear regression were analyzed. The major findings of this study indicate that the elderly in the voluntary work group have a high collectivism value, higher income earned by performing economic activities, and good cognitive health affected by a high satisfaction with life. From these research results, it was proved that a collectivism value is a common factor that affects satisfaction with life in both of the economic activity group. Those who were older had a traditional collectivism value. The voluntary work group showed a stronger collectivism value and higher satisfaction with life than the economic activity group. Thus, the diverse types of voluntary work should be developed and a systematic system should be established as methods for improving quality of life and satisfaction.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.2
• /
• pp.363-370
• /
• 2015

Olive flounder, Paralichthys olivaceus is one of the most target fish for aquaculture and national stock enhancement program in Korea. In order to find more information about hatchery fish stocking for stock enhancement we investigated the sex ratio of wild-caught fish populations which were artificially released into wild seas. The recapture rate was 9.0% to 94.5% in studied areas. The proportion of sex ratio ranged from 7.8% to 64.6% in female and from 34.4% to 92.1% in male respectively. This result suggests that the sex ratio of wild populations might be effected by the released fish. So we need more careful stocking program of the fish to preserve the balance of the sex ratio in the wild population.

• The Journal of the Korea Contents Association
• /
• v.12 no.8
• /
• pp.484-495
• /
• 2012

The purpose of this study was to investigate the effects of game-based-digital textbook on the basic arithmetic abilities and the task attention of students with mental retardation. To do this, 38 students with mental retardation participated and were assigned to the three groups. The first group only used the traditional text book, the second group only used the game-based-digital textbook, and the third group used both the traditional textbook and the game-based-digital textbook. The third group using both the traditional textbook and the game-based-digital textbook revealed more higher improvement than the other two groups in the basic arithmetic and the task attention.