• 아동학회지
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• 제29권4호
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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.

• 한국유기농업학회지
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• 제22권1호
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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.

• 한국과학교육학회지
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• 제17권3호
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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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• 제9권5호
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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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• 제6권1호
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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.

• 해양환경안전학회지
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• 제25권3호
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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.

• 한국정보처리학회논문지
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• 제5권1호
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• pp.73-85
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• 1998

최근에 개발되고 있는 소프트웨어들은 규모가 거대해지고 기능도 복잡 해지고 있다. 이처럼 복잡한 시스템의 개발을 위해 장기간에 걸쳐 서로 다른 전문가들의 협력 작업과 개발팀 구성원간에 정보 공유, 상호의존적 업무수행, 공동의 산출물 생성들의 작업을 지원하는 CSCW(Computer Supported Cooperative Works)개념을 소프트웨어 개발 방법에 통합하는 연구가 진행 중에 있다. 본 논문에서는 소프트웨어 개발에 있어서의 공동 작업 특성과 분산 컴퓨팅 환경에 의한 공동작업을 지원하여 생산성을 향상 시키는 CSCW개념을 적용하여 정보통신 소프트웨어 개발을 지원하는 하부 구조로서 다자간 공동작업 플랫폼인 SPACE(Software Platform for distributed Application sharing under Cooperative Environment)를 설계하였다. SPACE는 Windows 95 환경 하에서 완전 분산 구조를 가지고 있으며, 개발 도구를 공유하게 하는 공유기법으로 중앙 집중형 구조를 갖는 GUI 공유 방식과 복제 구조를 지원하기 위하여 이벤트 공유방식을 사용하고 있다.

• 한국과학교육학회지
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• 제19권2호
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• pp.266-274
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• 1999

본 연구에서는 협동적인 CAI와 개별적인 CAI가 중학생들의 과학 개념, 학업 성취도, 수업 환경에 대한 인식, 그리고 학습동기에 미치는 효과를 조사하였다. 중학교 3개 학급을 대상으로 분자 운동 단원에 대해 5차시 동안 협동적 CAI, 개별적 CAI, 전통적 수업을 실시하였다. 분석 결과 개념, 수업 환경에 대한 인식, 학습동기 검사에서 협동학습 집단의 평균이 전통적 수업 집단에 비해 유의미하게 높았으며, 개념의 파지 검사에서 협동학습 집단의 개념 이해도가 더 높게 나타났다. 또한, 개념의 파지 및 학습동기 검사에서 수업 처치와 사전 성취 수준 사이의 상호작용 효과가 있었다. 이에 대한 교육학적 함의를 논의하였다.

• 한국정보통신학회논문지
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• 제17권2호
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• pp.287-293
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• 2013

인지무선통신(Cognitive radio, CR)은 사용하지 않는 대역을 동적으로 활용할 수 있는 통신 방식이다. 여기서 CR 사용자는 주사용자와 동일한 스펙트럼을 공유하면서 주사용자에 대한 간섭을 최대한 배제해야한다. 일반적으로 각 CR 사용자는 자신이 속한 지역을 센싱하는 것으로 스펙트럼 사용 가능 여부를 판단한다. 하지만 CR 사용자가 다중 경로 페이딩이나 섀도잉와 같은 불확실한 무선 환경에 있을 경우 신호를 정확하게 감지하지 못할 확률이 높아진다. 이때 협력 센싱 기법을 활용할 경우 이러한 무선환경을 극복할 수 있게 된다. 본 연구에서는 협력 센싱 판정을 위해 연판정 기법을 활용할 때 주어진 시스템 요구치를 만족하면서 detection 확률을 향상시킬 수 있는 협력 노드 선택 알고리즘을 제안하였다. 여기서 SNR이 상대적으로 높은 협력 노드에 가중치를 주는 maximum ratio combining(MRC) 방식으로 최적의 협력 노드를 찾았다. 실험 결과, 제안한 알고리즘으로 시스템 요구치에 부합하는 최적의 센싱 노드를 선택할 수 있었다.

• International Journal of Control, Automation, and Systems
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• 제3권1호
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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.