• Korean Journal of Child Studies
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• v.29 no.4
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• pp.115-134
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• 2008

This study analyzed home environment, self-efficacy and parents' child rearing attitudes of disruptive children and of cooperative children in the classroom. Participants were 322 children(11-12 years of age) and 49 teachers. Instruments were four kinds of questionnaires. Data were analyzed by T-test and Fisher's exact test. Results of between group differences in parents' academic backgrounds showed more parents of cooperative children had completed high school. Disruptive children's mothers were more occupied outside the home; cooperative children's mothers engaged in more housework at home. Disruptive children's perceptions of their economic status were lower than cooperative children's perceptions. Results of comparison of general self-efficacy, scholastic self-efficacy, and home environment showed that disruptive children were statistically lower than cooperative children on all sub-variables.

• Korean Journal of Organic Agriculture
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• v.22 no.1
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• pp.25-46
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• 2014

Since organized living cooperative associations sold their environment-friendly agricultural products directly to independent consumers in the past, the general distribution channels such as wholesalers had difficulty in handling these products. However, the ratio of distribution via wholesale channel has been gradually increased as consumption of environment-friendly agricultural products has expanded. This study is to address vitalization of wholesale distribution for environment-friendly agricultural products by gathering previous statistical data and analysis. In addition, statistical analysis are conducted by utilizing surveys on forwarders, consumers for environment-friendly agricultural products. As a result, the products producers ship are distributed through dealers at producers sites, producers cooperatives, or food process companies, food companies, internet shopping malls, large-scale distribution companies, consumer groups such as living cooperative associations, direct outlets at consumers sites, or exports. Among the channels, the large-scale distribution companies and franchised special shops account for 47%, the general supermarkets 15.7%, and living cooperative associations 14.6% respectively. By utilizing the research results on producers and consumers, and the distribution weight by channels for environment-friendly agricultural products, the distribution channels for living cooperative associations, wholesale markets, and large scale distribution companies are compared and evaluated. As a result, the level of producers' and consumers' satisfaction for them is the lowest since the low selling price for producers and high distribution margins.

• Journal of The Korean Association For Science Education
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• v.17 no.3
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• pp.251-260
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• 1997

The instructional influences of cooperative learning strategies, which emphasize mutual interdependency of learners, group goal, and individual accountability, upon students' achievement, the attitude toward science instruction and the perception of learning environment were investigated. Before instruction, the prior knowledge test about atoms and molecules, the test of attitudes toward science instruction, and the perception questionnaire of learning environment were administered, and the grade in the previous mathematics course was obtained. These scores were used as covariates. Mid-term examination score was used as blocking variable. For instruction, three different strategies-traditional individual learning, small group learning, and cooperative learning-were used and teaching materials for the units of mole and stoichiometry were also prepared. After instruction, the researcher-made achievement test, the test of attitudes toward science instruction, and the perception questionnaire of learning environment were administered. The perception questionnaire of group activities was also administered to the two treatment groups. In the quantitative subtest, the scores of cooperative learning group and small group learning group were significantly higher than those of traditional individual learning group. However, the cooperative learning group's scores in the achievement test and the qualitative subtest were significantly higher than those of small group learning group and traditional individual learning group. The students in the cooperative learning group were found to have the most positive perception of learning environment but to have similar attitudes toward science instruction. No interaction between the treatment and the level of the previous achievement was found in any of the analyses. In the perception questionnaire of group activities, students in both small group learning group and cooperative learning group exhibited positive perception of group activities. However, students in the cooperative learning group tended to think that their activities were related with their group's success. Educational implications are discussed.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.515-522
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• 2011

In this paper, we investigate cooperative diversity in a spectrum sharing environment where secondary users utilize primary users' spectrum only if the interference power received at the primary users is maintained below a predetermined level. The outage probability of a selective decode-and-forward (DF) based cooperative diversity scheme in the secondary network is derived to analyze the effects of spectrum sharing on cooperative diversity. Our analytical and simulation results show that the outage probability is saturated at a certain level of transmit power of secondary users due to interference regulation, and, hence, cooperative diversity gains are lost. Through asymptotic analysis, we also identify the critical value of transmit SNR beyond which the outage probability is saturated.

• Educational Technology International
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• v.6 no.1
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• pp.103-119
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• 2005

This study investigated to designand implement web-based collaborative learning system Co-Net and map out students' learning procedure using the system, based upon Student Team Achievement Division (STAD Slavin, 1990, 1996). There are technical process and instructional considerations to be made during the design process. The former are those that concern equipment requirements and specifications and include Ease of Use, Speed of Access, and Flexibility. On the other hand, instructional considerationsare concerned with the delivery and access of instructional materials and their outcomes on learners. They are cooperative interactions within groups and group heterogeneity, learner control, group incentives, individual accountability, equal opportunity for earning high scores and contributing to group effort, task specialization, and competition among groups. A web site for a virtual learning environment designed and built by the authors and known as Co-Net is then explained along with the whole process learners inside the environment. The main page of Co-Net consists of 15 menus to implement cooperative learning process. The cooperative learning activities using 15 menus are composed of six phases (1) preparation of the new knowledge (2) presentation of the new knowledge (3) knowledge assimilation and application (4) team and individual evaluation (5) team and individual recognition Throughout the five phases, the appropriate use of cooperative learning techniques has been shown to have both academic and social benefits to learners.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.259-268
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• 2019

Even if only two ships are encountered, a collision may occur due to the mistaken judgment of the positional relationship. In other words, if an officer does not know a target ship's intention, there is always a risk of collision. In this paper, the experiments are conducted to investigate how the intention affects the action of collision avoidance in cooperative and non-cooperative situations. In non-cooperative situation, each ship chooses a course that minimizes costs based on the current situation. That is, it always performs a selfish selection. In a cooperative situation, the information is exchanged with a target ship and a course is selected based on this information. Each ship uses the Distributed Stochastic Search Algorithm so that a next-intended course can be selected by a certain probability and determines the course. In the experimental method, four virtual ships are set up to analyze the action of collision avoidance. Then, using the actual AIS data of eight ships in the strait of Dover, I compared and analyzed the action of collision avoidance in cooperative and non-cooperative situations. As a result of the experiment, the ships showed smooth trajectories in the cooperative situation, but the ship in the non-cooperative situation made frequent big changes to avoid a collision. In the case of the experiment using four ships, there was no collision in the cooperative situation regardless of the size of the safety domain, but a collision occurred between the ships when the size of the safety domain increased in cases of non-cooperation. In the case of experiments using eight ships, it was found that there are optimal parameters for collision avoidance. Also, it was possible to grasp the variation of the sailing distance and the costs according to the combination of the parameters, and it was confirmed that the setting of the parameters can have a great influence on collision avoidance among ships.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.73-85
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• 1998

Today's Software Systems are becoming bigger, larger and more complex than ever before. To develop largerscale projects, it is required that many experts of different fields participate and cooperate in the same project. So, it is an applied area of CSCW(Computer Supported Cooperative Works} that centers around methodologies and tools that enable cooperative works by geographically distributed people engaged in all aspects of product development. In this paper, we designed a multi-user cooperative works platform, SPACE(Software Platform for distributed Application sharing under Cooperative Environment} as a infrastructure that support to CSCW based system development for telecommunication and information system. SPACE has a fully distributed architecture under Windows 95 environment, has an application sharing mechanism enabling collaborative use of mteractive application adapt to a mixed GUI sharing technology which capture GUI and screen information, and also, an event sharing technology that has a replicated architecture.

• Journal of The Korean Association For Science Education
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• v.19 no.2
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• pp.266-274
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• 1999

This study investigated the effects of cooperative and individual computer-assisted instructions upon middle school students' science conceptions, achievement, perception of learning environment, and motivation. The cooperative, individual, and traditional learning groups were selected from a middle school, and taught about the motion of molecule for 5 class hours. Data analyses indicated that the students with cooperative computer-assisted instruction scored significantly higher than those with traditional instruction in the tests of conceptual understanding, perception of learning environment and motivation. Better understanding of the cooperative learning group was also found in a retention test of conceptions. In addition, there were significant interactions between the instruction and the level of prior achievement in the tests of retention of conceptions and motivation. Educational implications are discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.287-293
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• 2013

Cognitive radio has been recently proposed to dynamically access unused-spectrum. The CR users can share the same frequency band with the primary user without interference to each other. Usually each CR user needs to determine spectrum availability by itself depending only on its local observations. But uncertainty communication environment effects can be mitigated so that the detection probability is improved in a heavily shadowed environment. Soft detection is a primary user detection method of cooperative cognitive radio networks. In our research, we will improve system detection probability by using optimal cooperative node selection algorithm. New algorithm can find optimal number of cooperative sensing nodes for cooperative soft detection by using maximum ratio combining (MRC) method. Through analysis, proposed cooperative node selection algorithm can select optimal node for cooperative sensing according to the system requirement and improve the system detection probability.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.1-14
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• 2005

This paper presents an obstacle detection algorithm based on the consecutive and the cooperative range sensor scanning schemes. For a known environment, a mobile robot scans the surroundings using a range sensor that can rotate 3600°. The environment is rebuilt using nodes of two adjacent walls. The robot configuration is then estimated and an obstacle is detected by comparing characteristic points of the sensor readings. In order to extract edges from noisy and inaccurate sensor readings, a filtering algorithm is developed. For multiple robot localization, a cooperative scanning method with sensor range limit is developed. Both are verified with simulation and experiments.