• Journal of Korea Multimedia Society
• /
• v.4 no.4
• /
• pp.349-355
• /
• 2001

In this paper, we newly propose a performance enhanced CSMA/CD MAC(Medium Access Control) protocol for the Ethernet which changes its operation mode dynamically according to the network status, not fixed it as one of p-persistent mode and non-persistent mode. Dynamic mode change occurs independently on each node, and uses the consecutive success count and the fail count of the frame transmission. The simulation result shows that the dynamic mode change maintains the enhanced network utilization and transmission delay characteristics. Also we show the implementation simplicity of our MAC protocol through its conceptual design using the Ethernet commercial chip as it stands.

• Journal of the Korean Institute of Rural Architecture
• /
• v.8 no.2
• /
• pp.11-18
• /
• 2006

Ecomuseums come into close relationship with resident and community. Progress of heritage concept brings on the change of valuation standard in heritage, that life style of residents become most important element of cultural heritage. The change of display method has caused the generation of various experience programs in ecomuseum which are display and education based on participation of visitors and residents. Ecomuseums in Europe during progress have conceptual peculiarities by themes to keep the cultural identity and protect folk culture in regional community. 'Europe Ecomuseum Network' seriously affected by social change and development is new alternative to promote regional identity and cultural exchange among Europe countries. People participation with all residents is decisive factor to promote identity and attachment in native place, as well as collaboration with residents, experts, administrators and NGO is one factor for sustainable development and the realization of ecomuseum, activation of regional economy, and also is the root of efforts to protect and activate regional community.

• Journal of Korea Water Resources Association
• /
• v.43 no.8
• /
• pp.709-720
• /
• 2010

This paper describes the modeling of climate change impact on drought using a conceptual soil moisture model and presents the results of the modeling approach. The future climate series is obtained by scaling the historical series, informed by CCCma CGCM3-T63 with A2 green house emission scenario, using a daily scaling method that considers changes in the future monthly precipitation and potential evapotranspiration as well as in the daily precipitation distribution. The majority of the modeling results indicate that there will be more frequent drought in Korea in the future.

• Journal of The Korean Association For Science Education
• /
• v.20 no.3
• /
• pp.371-383
• /
• 2000

The purpose of this study is to compare junior high school students' conceptual changes about force and motion and their interest in science between a group with the instruction including sports experiential learning activities and a group with traditional instruction. In addition, for a group with sports experiential learning activities, students' conceptual changes and interest were examined according to the degree of their sports-experience before the instruction.The subject was 7th-grade students(N=82), and they were divided into two groups: experimental group and control group. The conceptual changes were positive in both groups. In the multiple choice questions the experimental group students(20.0%) were more positively changed than the control group students(17.2%). The number of students who responded with the right explanation increased 26.7% in the experimental group and 10.4% in the control group. The interest of the control group was significantly increased in the topic dimension(p<0.05). The interest of the experimental group was significantly increased in the experiential activity and the communicative activity(p<0.05). Students who had much sports-experience showed the most positive changes. Moreover the interest of these students was especially increased in internal motive, receptive activity, experiential activity, and communicative activity.

• Journal of Science Education
• /
• v.36 no.1
• /
• pp.84-93
• /
• 2012

We have studied possibilities of Peer Instruction(PI) to train in-service science teachers in elementary and middle schools through both degree of conceptual changes and investigating responses to questionaries. 169 teachers were attended and the subject for training was about light propagation to teach scientific conception about a pin hole camera. 6 conceptests were developed. Degree of conceptual changes was analyzed from results obtained from 24 elementary and 32 middle school teachers among them. On the other hand, answers to questionaries were obtained from 135. Relatively high gain near to about 0.7 in conceptual changes was obtained even though their initial levels were quite low. Interesting point is that elementary teachers have higher initial level and larger gain than middle school teachers. Teachers have very much enjoyed and showed strong support to PI for helping conceptual change, and willing to use PI to their own class. Also they conceived dealing concept in teacher training is very important and evaluated PI very positively for teacher training.

• Journal of the Korean earth science society
• /
• v.25 no.5
• /
• pp.348-363
• /
• 2004

The purpose of this study was to classify types of preconception about the motion of the moon held by middle school students and find out how the lesson applying cognitive conflict instructional model changes their conceptual view of the motion of the moon. A quantitative study was first conducted with 48 ninth graders and then followed by a qualitative study. In the qualitative study, male and female students were organized into groups of five and ten respectively. Students were instructed to observe the motion of the moon about for a month and at the same time were taught via the cognitive conflict instructional model for three class periods. Data were collected from interviews and a questionnaire evaluating the degree of concept development that each student showed. A majority of students were found to hold misconceptions formed from elementary school programs on the motion of the moon. Further, students showed lack of scientific ability to interpret the phenomena of the moon. This study showed that the cognitive conflict instructional model was effective for students to make progress regarding their conceptual views of the motion of the moon. However, it was observed that misconceptions by students may possibly occur when two dimensional figures or miniatures were used.

• Journal of Korea Water Resources Association
• /
• v.56 no.9
• /
• pp.563-574
• /
• 2023

Recently, climate change has affected functional responses of river basins to meteorological variables, emphasizing the importance of rainfall-runoff simulation research. Simultaneously, the growing interest in machine learning has led to its increased application in hydrological studies. However, it is not yet clear whether machine learning models are more advantageous than the conventional conceptual models. In this study, we compared the performance of the conventional GR6J model with the machine learning-based Random Forest model across 38 basins in Korea using both gauged and ungauged basin prediction methods. For gauged basin predictions, each model was calibrated or trained using observed daily runoff data, and their performance was evaluted over a separate validation period. Subsequently, ungauged basin simulations were evaluated using proximity-based parameter regionalization with Leave-One-Out Cross-Validation (LOOCV). In gauged basins, the Random Forest consistently outperformed the GR6J, exhibiting superiority across basins regardless of whether they had strong or weak rainfall-runoff correlations. This suggest that the inherent data-driven training structures of machine learning models, in contrast to the conceptual models, offer distinct advantages in data-rich scenarios. However, the advantages of the machine-learning algorithm were not replicated in ungauged basin predictions, resulting in a lower performance than that of the GR6J. In conclusion, this study suggests that while the Random Forest model showed enhanced performance in trained locations, the existing GR6J model may be a better choice for prediction in ungagued basins.

• Journal of the Korean earth science society
• /
• v.23 no.2
• /
• pp.132-139
• /
• 2002

One of the prime objectives of school science is to help the children learn science concepts and conceptual schemes that will help them understand and interpret their environment. One of the basic scientific concepts is 'Change -everything existing in universe is changing always'. The purpose of this study was to investigate the characteristics of elementary and secondary students' conception of change. The subjects for this study were 489 students in Korea; 111 fourth graders, 95 sixth graders, 140 seventh graders and 143 ninth graders. Four items - mountain, river, ground, sea -were used for investigating students conception of change because representing the nature world in elementary and secondary level. The subjects were asked to check whether each item was changing and to explain each their check. Students' explanations were classified by whether they were sound understanding geologically, or not. The rate of responses that each item was changing was compared by grades and the rate of geological explanations was also compared by grades. Because students' conceptions of change might were effected by time scale, the additional questions that asked students whether the present status of four items were equivalent to the that of several points of time. As a result, the rate of scientific answers and patterns of explanations were similar by grade and the rate of geological understandings was relatively low. The frequencies of concept of change were more dropped as the point of time was closer to present.

• Archives of design research
• /
• v.20 no.1 s.69
• /
• pp.189-202
• /
• 2007

This study was carried out to forecast the future paradigm of design from the perspective of change in social environment within which design evolves through the process of birth, growth, development, and decline rather than changes within design itself. In general, before man takes an action, he sets the aim with mental and conceptual value decided internally and he considers various tools and means in his circumstance externally. Then he decides his action based on the most resonable and economic way. This is the mechanism by which all the living subjects including the human being survive and evolve within the given environment. In this respect, the future of design can be also explored and speculated in terms of change of man's mental value and the technology in future (this view is the same with what socio-culturalists see both cultural and technological determinism as a major factor for social change). Based on the view above, the present study extracted major keywords for a possible change of future design based on keywords on the present mental value and norm, and the materialistic technology and economy.

• Proceedings of the Korean Institute of Interior Design Conference
• /
• 2008.05a
• /
• pp.116-122
• /
• 2008

As a model house has attempted a role change from a conceptual perspective as a housing cultural center starting from the 90ties, it began to direct the change into a high end building. In particular, large construction companies have recently invested on an unimagined scale, unlike in the past, in building a model house and pursued the construction of new attractions of cities as well as the upgrade of a brand image by hiring and implementing the designs of celebrity architects or designers. In addition, they have been in pursuit of a change by enhancing the satisfaction and pride of residents by offering spaces and programs for various cultural arts for apartment residents or potential customers and having them participate in those programs. This study aims to expound on the possibility of the utilization of a housing cultural center as a local complex community center by analyzing the spatial organization and the operational program of a housing cultural center appearing since the 90ties. With this aim, the study analyzed the cases of a complex community center and the program and the operational method of a housing cultural center within the case study in order to propose the possibilities for the utilization of a local complex community center. The elevation of the cultural and economic level of citizens and a rapid social change are shown as various demands for welfare, and the subsequent social physical change has led to the expansion of a space as a complex community. A housing cultural center is also directed to grow as a complex community center from the perspective of diverse demands and participations of consumers, and prepares a field for a broad spectrum of communications from the perspective of housing and cities.