• Journal of Life Science
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• v.22 no.8
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• pp.1085-1091
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• 2012

The purpose of this study is to investigate the effects of indoor and outdoor exercise environments on bone mineral density and body composition in old women. A total of 26 old women were randomly divided into two groups: an indoor exercise group (IE, n=13) and an outdoor exercise group (OE, n=13). The exercise groups performed moderate exercise (HR max 50~70%; RPE 11-15) three times a week for 60 minutes over 20 weeks. After exercise training, bone mineral density was significantly improved in the OE group as compared with the IE group. Body fat mass was significantly decreased in the IE group. Weight, lean body mass, and body fat mass were significantly decreased in the OE group. Body mass index was significantly decreased in the outdoor exercise group as compared to the IE group. Our findings show that a 20-week program of outdoor exercise training improves bone mineral density and body composition in old women. As mentioned above, it has been found that engaging in an outdoor exercise program for 20 weeks has a positive effect on bone mineral density and body composition in old women. In conclusion, engaging in the outdoor exercise program, including aerobic and resistance exercises, for 20 weeks improved bone mineral density and inhibited bone loss in old women and had a positive influence on vitamin D levels, thereby potentially lowering the risk of osteoporosis.

• School Mathematics
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• v.16 no.1
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• pp.157-180
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• 2014

This study investigated relationships between academic stress and mathematics learning motivation focusing on the mediating effect of academic motivation types. It also tested differential structural relationship among the variables in the high vs. low academic achievement level groups and the boys vs. girls of middle schools. The participants were 952 second graders from five middle schools. Student scores from the standardized tests that were developed to assess the students' academic stress, mathematics learning motivation, and three types of motivation (amotivation, controlled motivation, and autonomous motivation) were used in this study. The results demonstrate that there were significant differences in the relationship patterns of the research variables. Correlation analysis provided evidences that academic stress was negatively related with mathematics learning motivation and autonomous motivation but positively related with amotivation and controlled motivation. Also, mathematics learning motivation was negatively related with amotivation and controlled motivation but positively related with autonomous motivation. Structural equation modelling analysis provided the evidence that the full mediation model was a significant, in that the students' types of academic motivation mediated the effect of academic stress on mathematics learning motivation. Multiple group analysis revealed that there were group differences in the path coefficients of the structural model. But the academic stress showed negative influence on the mathematics learning motivation via amotivation and autonomous motivation in all groups.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.527-538
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• 2016

The purpose of this study is to select the factors of 'Group scientific creativity' and to find out how 'Group scientific creativity' turns out in the creative problem-solving process of students. To select the factors that affect 'Group scientific creativity', this research extracted 27 influencing factors on the group creativity from the prior study and organized them according to opinions of education experts. To select factors that affect 'Group scientific creativity' in the creative problem-solving process of students, this research analyzed the group problem-solving process that has been done on 72 gifted students for two days. Main results of the study is as follows: First, nine elements such as scientific thinking, scientific knowledge, scientific information-processing capacity, motivation, challenge, age and gender, existence of diversity, creativity educational experience, and the group cohesiveness were selected as human factors. Four elements such as scientific communication skills, scientific inquiry process, autonomy, and leadership were selected as the combining factors. Also, three elements such as the learning environment, teacher types, and compensation were selected as the Environmental factors. Second, it was possible to find that the group scientific creativity influence factors affecting the creative process by analyzing the gifted students in creative-problem solving process. Based on these results, this study described additional points on the factors improving 'Group scientific-creativity.'

• Journal of Aquaculture
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• v.19 no.3
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• pp.205-209
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• 2006

Genetic change from broodstock to hatchery stock of the olive flounder Paralichthys olivaceus and effective number of breeders (Ne) were investigated by the different fertilized-egg collecting methods; E1 (eggs collected one day after spawning) and E2 (eggs collected two days after spawning) using seven microsatellite loci (Kop2, Kop22, Kop18, Kop3, Kop21, Kop9 and Kop26) for the better understanding of stock enhancement. Observed heterozygosity in three stocks ranged from 0.651 at Kop3 to 0.928 at Kop22, with offspring being slightly higher heterozygous over their parents. However, the genetic reduction of offspring was significant. The offspring allele number per locus was reduced to 23.5% for E1 and 17.6% for E2 of their maternal number. Ne to the hatchery stock was estimated to be 21.9 for E1 and 34.3 for E2. The inbreeding coefficients of populations El and E2 were 0.023 and 0.015, respectively. The present study suggests the extension of the egg collection period for a recovery of the genetic diversity in artificially produced offspring.

• Korean journal of communication and information
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• v.46
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• pp.387-419
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• 2009

The concept of strategic group is defined as an aggregate of corporations utilizing similar strategies with similar resources. It becomes a kinds of contact point in the middle of corporation and industry between the industrial organization theory and the strategic management theory. This study tried to apply the strategic group model, which has been a main theory in the management studies, to program providing industry in Korea. This study shed lights upon research problems such as number of strategic groups, differences of strategic variables among the groups, finally differential performances according to strategic groups. 40 commercial broadcasting companies were analyzed to find answers. 9 strategic groups were drawn as a result of cluster analysis. Major variables which contribute to making groups were operating efficiency(4.05), pricing(3.83), size(number of system operator, 3.56), reliance on license revenue(2.58), horizontal integration(number of sister networks, 2.16) in order. An analysis of variance between performance variables has shown statistical significance regarding total net revenue per subscriber, however, insignificances statistically in regards to ratio of operating profit to net sales, cash Abstracts 687 flow ratio. Some studies in the past insisted that history variable played an important role to classifying strategic groups. However, this study found that the history didn't exert significant influence on either the group classification itself or performance.

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.389-397
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• 2013

In this study, the effects of STAD cooperative learning strategy on students' achievement, learning motivation, perceptions of learning environment, and perceived classroom goal structure were investigated in terms of students' collectivism level. Two classes (64 students) from an elementary school were respectively assigned to a control group and a treatment group. A individualism-collectivism test, a learning motivation test, a perceptions of learning environment test, and a perceived classroom goal structure test were administered as pretests. The intervention of cooperative learning lasted for 24 class periods. After instruction, an achievement test, the learning motivation test, the perceptions of learning environment test, and the perceived classroom goal structure test were administered. The results indicated that the students of the treatment group significantly outperformed those of the control group in the achievement test. There was a significant treatment-aptitude interaction effect in the scores of the attention subcategory of the learning motivation. In the perceptions of learning environment, the score of the treatment group was significantly higher than the control group in the cohesiveness subcategory, whereas the score of the treatment group was significantly lower than their counterpart in the competitiveness subcategory. It was also found that the score of the treatment group was significantly higher than the control group in the performance subcategory of the perceived classroom goal structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.1075-1081
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• 2013

Twitter, Facebook, and KakaoStory are the major SNS in Korea. Social knowledge production is being produced by those services from numerous collaboration and co-participation in those SNS. Wikipedia or Naver JishikIN service was regarded as the representative product of collective knowledge production during the wired internet era. However now at the wireless internet era centered with smart phones, various forms of collective knowledge production would be achieved by connecting to SNS in real-time. In this thesis, the survey data of collective knowledge production for users of three SNS have been compared and analyzed. The difference of the collective knowledge production mechanism among Twitter, Facebook and KakaoStory has been studied and compared through three variables: the motivation of collective knowledge production, the preference of collective knowledge production model, and collective knowledge production cultural perception. As a result of the analysis of the discriminant factors for three SNS user groups, it turns out that the diversity-toward usage motivation, personal contribution motivation, and collective knowledge production tendency perception are the most influential variables. This thesis is of significance in that it unites the value of social science such as social capital and collective knowledge production from the viewpoint of computer science and opens the new chapter of collective knowledge production with the real-time SNS of wireless internet from the wired internet.

• Journal of Science Education
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• v.40 no.2
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• pp.131-143
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• 2016

This research was conducted to investigate the effects under which learner-generated pictorial representation introduced in summary stage of lesson serve as an instructional strategy improving academic achievement and scientific attitude. The subjects of this study were 152 students (experimental group: 38 boys and 39 girls, control group: 36 boys and 39 girls). Using the learner-generated pictorial representation were applied to experimental group, whereas summarizing the lesson in writing to control group. The results of this study were as follows: First, there was no significant difference between the two groups in the post achievement results. But, a statistically significant difference on a delayed post-test of academic achievement was found between experimental and control groups. Second, there was no significant difference between boys and girls in the post achievement test. But a significantly positive effects on the academic achievement was found in boys of experimental group. Third, experimental group scored higher than the control group in all sub-domains of the scientific attitude; curiosity, openness, criticism, cooperativity, willingness, perseverance. Findings suggest the descriptive drawing is a viable way for elementary students to understand scientific concepts and to improve scientific attitude.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.522-529
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• 2016

This study examined the effects of 4-weeks of backward walking exercise on ROM, VAS (Visual Analogue Scale) score and proprioception in anterior cruciate reconstruction patients. Fourteen subjects were randomly assigned to either a backward walking group (BWG, n=7) or a control group (CON, n=7) and then participated in rehabilitation program for 4 weeks. The ROM of the flexion significantly decreased in both groups (BWG, p<0.001 vs CON, p<0.01), while ROM of extension significantly decreased only in the BWG (p<.05) post exercise, but no significant difference was observed between groups. Additionally, VAS score decreased significantly in both groups (P<0.001) and BWG was lower than CON post exercise (p<0.001). Finally, proprioception decreased significantly in both groups (BWG, p<0.001 vs CON, p<0.05), but did not differ significantly between groups. These results suggest that the 4 week backward walking rehabilitation program improves ROM, VAS score, and proprioception and has positive effects on functional recovery of anterior cruciate ligament reconstruction patients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.772-780
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• 2008

K-means is one of the simplest unsupervised learning algorithms that solve the clustering problem. However K-means suffers the basic shortcoming: the number of clusters k has to be known in advance. In this paper, we propose extensions of X-means, which can estimate the number of clusters using Bayesian information criterion(BIC). We introduce two different versions of algorithm: modified X-means(MX-means) and generalized X-means(GX-means), which employ one full covariance matrix for one cluster and so can estimate the number of clusters efficiently without severe over-fitting which X-means suffers due to its spherical cluster assumption. The algorithms start with one cluster and try to split a cluster iteratively to maximize the BIC score. The former uses K-means algorithm to find a set of optimal clusters with current k, which makes it simple and fast. However it generates wrongly estimated centers when the clusters are overlapped. The latter uses EM algorithm to estimate the parameters and generates more stable clusters even when the clusters are overlapped. Experiments with synthetic data show that the purposed methods can provide a robust estimate of the number of clusters and cluster parameters compared to other existing top-down algorithms.