• Asian-Australasian Journal of Animal Sciences
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• v.22 no.7
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• pp.923-930
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• 2009

This study was conducted to compare three models: two random regression models with and without considering heterogeneity in the residual variances and a lactation model (LM) for evaluating the genetic ability of Holstein cows in Korea. Two datasets were prepared for this study. To apply the test-day random regression model, 94,390 test-day records were prepared from 15,263 cows. The second data set consisted of 14,704 lactation records covering milk production over 305 days. Raw milk yield and composition data were collected from 1998 to 2002 by the National Agricultural Cooperative Federation' dairy cattle improvement center by way of its milk testing program, which is nationally based. The pedigree information for this analysis was collected by the Korean Animal Improvement Association. The random regression models (RRMs) are single-trait animal models that consider each lactation record as an independent trait. Estimates of covariance were assumed to be different ones. In order to consider heterogeneity of residual variance in the analysis, test-days were classified into 29 classes. By considering heterogeneity of residual variance, variation for lactation performance in the early lactation classes was higher than during the middle classes and variance was lower in the late lactation classes than in the other two classes. This may be due to feeding management system and physiological properties of Holstein cows in Korea. Over classes e6 to e26 (covering 61 to 270 DIM), there was little change in residual variance, suggesting that a model with homogeneity of variance be used restricting the data to these days only. Estimates of heritability for milk yield ranged from 0.154 to 0.455, for which the estimates were variable depending on different lactation periods. Most of the heritabilities for milk yield using the RRM were higher than in the lactation model, and the estimate of genetic variance of milk yield was lower in the late lactation period than in the early or middle periods.

• Journal of The Korean Association For Science Education
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• v.24 no.3
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• pp.659-667
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• 2004

The purposes of this study were to examine the middle school science textbooks published according to the 7th curriculum by analyzing overall structure of the books and STS contents, and to diagnose the current status of STS education in science classroom through interviews with teachers and students of the middle schools. It was found that STS approaches were of increasing importance in the science textbooks, however, they were not popular in the science classes. STS topics in the middle school textbooks were related mostly to 'applications of science' and 'social problems and issues', and few of the topics were related to 'cooperative work on real problems', 'multiple dimensions of science' and 'practice with decision making strategies'. Major barriers of STS education implementation in middle school science classroom were identified as follows; difficulties of assessment, teachers' insufficient cognitions and experiences regarding STS education, perceptions of students and parents that prefer didactic lecture methods and working on exercises. Desirable directions for the improvement of present status of STS education in middle school science classes were proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.384-387
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• 2022

This study was conducted to design and apply simulation-based problem-based learning classes, and then analyze the effects of class management using focus group interviews. In paramedicine, practical learning that can respond to various emergency situations based on major knowledge is important. In the case of problem-based learning classes, it is suitable for operating various topics covered by the Department of Paramedicine as it can improve capabilities such as problem-solving strategies, skills, and teamwork by providing practicality related to field situations for learning. This study developed a PBL module focusing on patients with dyspnea and applied it to medical emergencies and practice courses taken by 16 third graders of S University's Paramedicine department. Overall class satisfaction was high from 4.76 to 4.92. In particular, by resetting the learning strategy through PBL classes and experiencing cooperative learning, positive learning outcomes could be obtained and self-efficacy was experienced.

• Journal of The Korean Association of Information Education
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• v.9 no.2
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• pp.197-208
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• 2005

For the wide spread of cyber education, it is important to understand the instructional characteristics of cyber education and its applications in the educational sites which help to cope with the practical needs and problems. This study was conducted to analyze the experience of cyber classes(working hours, tasks and evaluation, satisfaction level and instructional effectiveness, suggestions for cyber education) and use of instructional methodology (instructional activities, interaction frequencies, cooperative learning activities, instructional activities toward knowledge building). The data was collected from pre-service teachers(403) and in-service teachers(318) in June 2004. The results were that pre-service and in-service teachers all consider the satisfaction level and academic achievement level of cyber classes lower than that of FTF classes. Particularly the boring presentation of instructional materials and the inadequate instructional strategies for cyber classes were the biggest complains, and lack of interaction among peer groups and with instructors, lack of learning opportunity for cyber instructional strategies, limited group activities, lack of interaction with experts were followed. Limited types of evaluation also showed that cyber classes focus on results more than the process of students' academic achievement.

• English Language & Literature Teaching
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• v.9 no.2
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• pp.1-16
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• 2003

This paper describes a video exchange project between English classes in South Korea and in Japan. Korean and Japanese students worked in groups to make short videos in English which were then exchanged. After viewing their counterparts' videos, students e-mailed feedback to each other. This project was the third video exchange project between Korean and Japanese university students since 2001. However, it was the first time to try it with three universities together. Students from the different universities tried to compete with each other. It provided a better chance for students to improve their English. Most students expressed the importance of the video exchange project in developing their English proficiency and enabling them to use English in an international context. Many students agreed that the project was an educational, enjoyable and worthwhile experience.

• English Language & Literature Teaching
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• v.11 no.1
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• pp.57-76
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• 2005

This study provides a rationale for using project-based learning with Korean students of English in Korea; in addition, it describes the process of creating and implementing project-based learning in the classroom and gives examples of how this unique teaching and learning method has been used successfully to teach learners with different levels of English proficiency. The first two chapters of the study examine the nature of project-based learning by comparing it with related fields of study, such as language teaching syllabi and methods, cognitive psychology, constructivists' views and interaction theory. The latter part of the study deals with issues related to applying project-based learning in Korean English classes. It emphasizes the importance not only of motivating active group effort and participation, but also in creating a trusting, cooperative relationship between group members in order to have a successful accomplishment of a project. The study concludes with implications for future studies.

• IE interfaces
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• v.17 no.2
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• pp.142-148
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• 2004

The objective of bridge construction cost allocation is to distribute in a fair and rational manner the bridge construction costs among those vehicles using the bridge. In most bridge construction cost allocation studies, bridge construction costs are mainly distributed according to traffic load(gross vehicle weight), without any consideration of bridge capacity requirements(the number of lanes). In this paper, a bridge cost allocation method for considering both traffic capacity and traffic loads is developed. The proposed method is based on cooperative game theory, particularly two concepts known as the Aumann-Shapley (A-S) value and Shapley value. This method can help to analyze the impact of traffic capacity costs. By applying the proposed method to an example, traffic capacity cost is found to be high so that traffic capacity should be considered to allocate the bridge construction costs to vehicle classes in a more equitable manner.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.176-181
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• 2001

Due to the increasing complexity to handle conflicts and interruptions caused by resource failures and rush orders, shop control is obliged to redesign its organization according to the changing demands of the manufacturing control. These demands are leading to the development of decentralization and gradually to their permanent optimization. As a result, a powerful modeling method which can be adapted efficiently is required. The use of agent theory enables specific modeling of the relevant shop planning activities. The planning activities are modeled in a so-called activity modeling through the definition of three classes of agents; Plan Agent, Manufacturing System Agent and Control Agent as well as the description of the cooperative relationship among these agents. On the basis of the activity model the agent-based shop control method is developed which emphasizes the distributed problem-solving and the cooperation with relevant agents.

• Honam Mathematical Journal
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• v.28 no.2
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• pp.185-196
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• 2006

A scheme based on the cryptography for enforcing multilevel security in a system where hierarchy is represented by a partially ordered set was first introduced by Akl et al. But the key generation algorithm of Akl et al. is infeasible when there is a large number of users. In 1985, MacKinnon et al. proposed a paper containing a condition which prevents cooperative attacks and optimizes the assignment in order to overcome this shortage. In 2005, Kim et al. proposed key management systems for multilevel security using one-way hash function, RSA algorithm, Poset dimension and Clifford semigroup in the context of modern cryptography. In particular, the key management system using Clifford semigroup of imaginary quadratic non-maximal orders is based on the fact that the computation of a key ideal $K_0$ from an ideal $EK_0$ seems to be difficult unless E is equivalent to O. We, in this paper, show that computing preimages under the bonding homomorphism is not difficult, and that the multilevel cryptosystem based on the Clifford semigroup is insecure and improper to the key management system.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.2
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• pp.59-66
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• 2009

This study is purposed to find out practical problems, explore possible changes and provide qualitative development and development policies of elementary school physical education facilities and training aids. The following is concluded through three rounds of Delphi questionnaires. First, the highest possible change is predicted in that obsolete sports facilities should be replaced and various training aids be purchased. Second, gyms should be established for ensuring indoor sports space and indoor sports facilities should be expanded. Third, modernization and advancement of sports facilities and training aids should be implemented by attracting private investment. Fourth, sports facilities at schools and communities should be exchanged for free. Fifth, sports facilities in the school playground should be diversified for physical education classes by putting play ground facilities in good conditions. Sixth, it is predicted that a sound distribution system can be established for ensuring creative, strong sports facilities and training aids. A department may take full responsibility of buying sports materials and establish an alternative idea for cooperative buying.