• Water Engineering Research
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• v.5 no.2
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• pp.101-109
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• 2004

Aggregating information by combining forecasts from two or more forecasting methods is an alternative to using forecasts from just a single method to improve forecast accuracy. This paper describes the development and use of a monthly inflow forecast model based on an optimal linear combination (OLC) of forecasts derived from naive, persistence, and Ensemble Streamflow Prediction (ESP) forecasts. Using the cross-validation technique, the OLC model made 1-month ahead probabilistic forecasts for the Chungju multi-purpose dam inflows for 15 years. For most of the verification months, the skill associated with the OLC forecast was superior to those drawn from the individual forecast techniques. Therefore this study demonstrates that OLC can improve the accuracy of the ESP forecast, especially during the dry season. This study also examined the value of the OLC forecasts in reservoir operations. Stochastic Dynamic Programming (SDP) derived the optimal operating policy for the Chungju multi-purpose dam operation and the derived policy was simulated using the 15-year observed inflows. The simulation results showed the SDP model that updated its probability from the new OLC forecast provided more efficient operation decisions than the conventional SDP model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.161-168
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• 2009

We demonstrated $\check{S}$olc-type wavelength filters in periodically poled Ti-diffused lithium-niobate channel optical waveguide (Ti:PPLN). A $\check{S}$olc-type transmission spectrum based on the polarization-mode conversion was observed experimentally in PPLN with period 16.6${\mu}m$. A reasonable explanation of such a phenomenon was presented. A polarization-mode converted transmission peak was observed at wavelength 1272.49nm. The FWHM and sidelobe of spectrum are about 0.23nm and 7 dB, respectively.

• Journal of The Korean Association of Information Education
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• v.13 no.4
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• pp.409-421
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• 2009

As the use of Internet becomes popular along with the rapid progress of digitalization, educators increasingly pay attention to online education as a method to complement the current educational system. Especially the Online Learning Community(OLC) has been successfully utilized for teacher education in many advanced countries including the U.S.A.. Considering such trend, this research analyzed representative cases which used the OLC for teacher education in the U.S.A. and explored major factors for successful construction and management of the OLC. Among various cases, five OLCs operated by universities and research institutes were selected, and special aspects of these OLCs were compared and analyzed. On the basis of the five case studies, this research suggested ten factors to be implemented for the successful construction and management of the OLC for teacher education.

• 한국지구과학회:학술대회논문집
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• 2004.02a
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• pp.20-20
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• 2004

• Korean Journal of Construction Engineering and Management
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• v.5 no.5 s.21
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• pp.109-116
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• 2004

Recently, many korean construction companies have faced many environmental changes and demands for external changes. This demand for external changes is necessary for all companies that is under the survival of fittest. The internal/external of environmental changes affect the organizations of company largely, and these management organizations have relation with the corporate of management performance closely. In response to that, to be adapted to the environmental change and to raise the corporate of management performance, the construction companies have tried to change the organizations such as organization re-design, organization re-build, organization innovation. Because the organizational structure that is preventive in the growth of companies bring a negative effect, the companies need to have the effective organizations to raise the corporate value. The effective organizations could be used the important indicator that builds the corporate goals and manages the organizations. Also, the organization development and organization management can prepare for environmental changes can be the important base to increase the management performance. Therefore, After surveying and analyzing the character of organization structure in respect to the OLC, this study present the Organization Structure Model that can design the appropriate organization by the growth of companies.

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.84-85
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• 2009

• Educational Technology International
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• v.11 no.2
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• pp.43-75
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• 2010

The purpose of this study is to identify patterns of learner behaviors, conflicting and facilitating factors during collaborative work in an online learning community(OLC). This study further seeks to investigate the difference of learner behaviors between high- and low-performing groups, and conflicting and facilitating factors. The online postings from four groups(19 students) in the spring semester(study 1) and six groups(24 students) in the fall semester(study 2) were analyzed. A coding scheme was generated based on constant comparison using the qualitative data analysis tool, NVivo. The analysis identified 7 categories of learner behaviors in both studies. Among the seven categories, information seeking and co-construction were most frequently observed in both studies. One evident difference between the high- and low-performing groups was that the high-performing groups revealed more incidents of learner behaviors in both studies. In addition, six categories of conflicting factors and five categories of facilitating factors were emerged in both studies. The inefficiency of work category was one of the most frequently observed categories in both studies. Interestingly, the high-performing groups showed more incidents of conflicting factors than the low-performing groups. This study revealed two different types of conflicting factors and there is a need for different moderating strategies depending on its type. Based on the results of the study, effective design strategies for an OLC to facilitate active learning were suggested.

• 한국지구과학회:학술대회논문집
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• 2006.02a
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• pp.93-93
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• 2006

• Food Science of Animal Resources
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• v.23 no.1
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• pp.46-49
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• 2003

Classwort (Salicornia herbacea L.), a halophyte, is a potential functional food resource in Korea. This study was conducted to determine the antioxidant activity of glasswort, as a functional food material, on the lipid oxidation of pork. To compare antioxidant effect of different parts of glasswort, samples such as dried ground leaves, stems, and roots of glasswort were prepared. The antioxidant activity was determined by the TBARS(Thiobarbituric Acid Reactive Substances) method. Freeze-dried leaves of glasswort at 0 day of storage had the lowest TBARS values, suggesting the highest antioxidant effect. But the antioxidative effect of freeze-dried leaves of glasswort was less than that of BHT. At 7 days after storage, however, the values were not different from oven-dried leaves. The oven-dried leaves at 14 days after storing should highest antioxidative activity. In conclusion, antioxidative effect of glasswort was apparently exhibited through measurement of TBARS. Antioxidative effect from ground leaf sample of glasswort harvested in coastal region was the highest, followed by root and stem samples. Glasswort had twice as high antioxidative effect as sea salt and bamboo salt.

• Journal of Korea Water Resources Association
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• v.38 no.6 s.155
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• pp.471-483
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• 2005

A monthly Ensemble Streamflow Prediction (ESP) system was developed by applying a daily rainfall-runoff model known as the Streamflow Synthesis and Reservoir Regulation (SSARR) model to the Han, Nakdong, and Seomjin River basins in Korea. This study first assesses the accuracy of the averaged monthly runoffs simulated by SSARR for the 3 basins and proposes some improvements. The study found that the SSARR modeling of the Han and Nakdong River basins tended to significantly underestimate the actual runoff levels and the modeling of the Seomjin River basinshowed a large error variance. However, by implementing optimal linear correction (OLC), the accuracy of the SSARR model was considerably improved in predicting averaged monthly runoffs of the Han and Nakdong River basins. This improvement was not seen in the modeling of the Seomjin River basin. In addition, the ESP system was applied to forecast probabilistic runoff forecasts one month in advance for the 3 river basins from 1998 to 2003. Considerably improvement was also achieved with OLC in probabilistic forecasting accuracy for the Han and Nakdong River basins, but not in that of the Seomjin River basin.