• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.448-454
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• 2020

This study aims to determine the cause of structural defects occurring during aircraft operations and to verify the structural integrity of the improved features. The fracture plane was analyzed to verify the characteristics of the cracks and the fatigue failure leading to the final fracture was determined by the progress of the cracks by the repeated load. During aircraft operations, the comparative analysis of the load measurement data at the cracks with the aircraft design load determined that the measured load was not at the level of 30% of the design to be capable of being damaged. A gap analysis resulted in a significant stress of approximately 32 ksi at the crack site. Pre-Load testing also confirmed that the M.S. was reduced by more than 50% from +0.71 to +0.43, resulting in a sharp increase in aircraft load and the possibility of cracking when combined. Thus, structural reinforcement and the removal of the gap for aircraft cracking sites improved the defect. Based on the structural strength analysis of the improvement features, the bulkhead has a margin of about +0.88 and the fitting feature is about +0.48 versus allowable stress. In addition, the life analysis results revealed an improvement of approximately 84000 hours.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.225-233
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• 2015

This study was conducted in an attempt to determine the factors that cause excessive daytime sleepiness among 927 subway station employees located in Seoul. Data were collected with a structured questionnaire through the web site and were analyzed using SPSS 20.0 statistical software. Results showed that marital status made a statistically significant difference in general characteristics, and hobby/leisure activities made a statistically significant difference in health-related characteristics. Workplace and satisfaction with the organization made a significant difference in job-related characteristics, and physical environment, job demand, job autonomy, relationship conflicts, organizational system, inappropriate compensation, and organizational culture made a statistically significant difference in job stress factors. Factors that affect excessive daytime sleepiness were hobby and leisure activities, satisfaction with the organization, physical environment, job demand, job autonomy, organizational system and organizational culture, showing a 20.5% explanatory power. This study proposes the operation of programs that can improve the physical environment, change the organizational system and increase satisfaction with the organizational culture among station employees in order that they can enjoy their hobby/leisure life and relieve job stress so that they can avoid excessive daytime sleepiness.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.461-476
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• 2013

Carnegie-Ames-Stanford Approach (CASA) model is one of the most quick, convenient and accurate models to estimate the NPP (Net Primary Productivity) of vegetation. The purposes of this study are (1) to examine the spatial and temporal patterns of vegetation NPP of the paddy field area in Korea from 2002 to 2012, and (2) to investigate how the rice productivity responded to inter-annual NPP variability, and (3) to estimate rice yield in Korea using CASA model applied to MOderate Resolution Imaging Spectroradiometer (MODIS) products and solar radiation. MODIS products; MYD09 for NIR and SWIR bands, MYD11 for LST, MYD15 for FPAR, respectively from a NASA web site were used. Finally, (4) its applicability is to be reviewed. For those purposes, correlation coefficients (linear regression for monthly NPP and accumulated NPP with rice yield) were examined to evaluate the spatial and temporal patterns of the relations. As a result, the total accumulated NPP and Sep. NPP tend to have high correlation with rice yield. The rice yield in 2012 was estimated to be 526.93kg/10a by accumulated NPP and 520.32 kg/10a by Sep. NPP. RMSE were 9.46kg/10a and 12.93kg/10a, respectively, compared with the yield forecast of the National Statistical Office. This leads to the conclusion that NPP changes in the paddy field were well reflected rice yield in this study.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.1 s.108
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• pp.93-108
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• 2005

Fresh Kills is the largest landfill in the world located in the west side of Staten Island, New York. The landfill served as a storage area for New York City's trash for more than 50 years. After years of civilian and political pressure, state and local legislation decided its closure of landfill operation in Fresh Kills in March 2001. Soon after, Department of City Planning announced a Fresh Kills international design com-petition: 'Landfill to Landscape'. The winning entry was promised to be outline for the redevelopment of the 2,200 acre site which the size of three times Central Park. Forty-eight teams representing more than 200 offices from around world submitted proposals, from which six finalists that mostly led by landscape architects were selected. In December 2001, a jury of architects, landscape architects and city officials unanimously selected Field Operations as the winner. The plan, named Lifescape, visualizes the gradual 20-year transformation of the whole Staten Island into a 'natural lifestyle island' recognizing that Staten Island is home to coastal wetlands that shelter one of the most diverse ecosystems in the New York metropolitan area. It suggested that an ecologically reconstituted Fresh Kills could become the center of integrated parks and greenways system on the island otherwise fragmented. The project will be one of the largest and most ambitious undertakings in the metropolis in years developing a complex web of habitats and parklands on top of mountain of trash. This study tries to achieve two goals: One is to provide general explanations on the project, Lifescape, breaking down to its background, geographical context, design concepts and phased development plan. Another is to introduce the unique and innovative design approaches by Field Operations that are different from a conventional landscape architectural attitude. Since this project was well published through many magazines and newspapers, main focus will be upon aspects that differentiate this project from usual landscape projects. Conceptually Lifescape brought provocative notions on nature/culture relationship and the role of urban park as an active agency rather than just a green rest area. Also this project introduced pioneering graphics like plan collage, diagrammatic plan, phasing diagram and photo montage as vehicles conveying information, imagination and provocation. Witnessing the influence of the project gradually in the field of academic and practice in the States, this study is intended to become a constructive reference to similar landscape projects dealing with large and complex urban context in conjunction with restructure of contemporary city.

• Atmosphere
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• v.24 no.3
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• pp.433-444
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• 2014

Although the Radar-AWS Rainrate (RAR) calculation system operated by Korea Meteorological Administration estimated precipitation using 2-dimensional composite components of single polarization radars, this system has several limitations in estimating the precipitation accurately. To to overcome limitations of the RAR system, the Korea Meteorological Administration developed and operated the RMQ (Radar-based Multi-sensor Quantitative Precipitation Estimation) system, the improved version of NMQ (National Mosaic and Multi-sensor Quantitative Precipitation Estimation) system of NSSL (National Severe Storms Laboratory) for the Korean Peninsula. This study introduced the RMQ system domestically for the first time and verified the precipitation estimation performance of the RMQ system. The RMQ system consists of 4 main parts as the process of handling the single radar data, merging 3D reflectivity, QPE, and displaying result images. The first process (handling of the single radar data) has the pre-process of a radar data (transformation of data format and quality control), the production of a vertical profile of reflectivity and the correction of bright-band, and the conduction of hydrid scan reflectivity. The next process (merger of 3D reflectivity) produces the 3D composite reflectivity field after correcting the quality controlled single radar reflectivity. The QPE process classifies the precipitation types using multi-sensor information and estimates quantitative precipitation using several Z-R relationships which are proper for precipitation types. This process also corrects the precipitation using the AWS position with local gauge correction technique. The last process displays the final results transformed into images in the web-site. This study also estimated the accuracy of the RMQ system with five events in 2012 summer season and compared the results of the RAR (Radar-AWS Rainrate) and RMQ systems. The RMQ system ($2.36mm\;hr^{-1}$ in RMSE on average) is superior to the RAR system ($8.33mm\;hr^{-1}$ in RMSE) and improved by 73.25% in RMSE and 25.56% in correlation coefficient on average. The precipitation composite field images produced by the RMQ system are almost identical to the AWS (Automatic Weather Statioin) images. Therefore, the RMQ system has contributed to improve the accuracy of precipitation estimation using weather radars and operation of the RMQ system in the work field in future enables to cope with the extreme weather conditions actively.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.526-536
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• 2004

This study was undertaken to determine the effect of a 2.2mg/Kg/day intraoral administration of NaF on the amount of root resorption and osteoclastic activity during or after a rapid maxillary expansion procedure. Ten puerile female dogs were divided into two groups: a control group and a NaF-treated group. A fixed type maxillary expansion device was delivered to all dogs. The appliance was activated twice daily throughout a 20-day period, causing a 5-mm expansion of maxillary bone. After the expansion procedure, the animals were sacrificed at days 0, 15, 30, 45, and 60 of the retention period. The buccal surface of the root of each maxillary canine was examined by means of a surface electron microscope (SEM). Using SEM, web-like resorption lacunae were observed on the bone or the tooth surface at the site of osteoclastic activity; these observations were verified by histological methods. No peculiar resorption lacunae were found in the apical tip of the roots of either the control group or the NaF-treated group animals. The NaF-treated retention group was found to have less resorption lacunae formation on day 45 and day 60. The preventative effect of NaF on resorption lacunae formation on the surface of the bone covering the anchor tooth was confirmed. Larger areas of resorption lacunae were found on the surface of the bone covering the canines in the control group animals, as compared to those of the NaF-treated group, especially on day 30 and day 60. Using SEM, the present study revealed a difference between the control group and the NaF-treated group in the prevalence and the size of the resorption lacunae formation on the cemental root surface. The preventative effect of NaF on bone resorption was confirmed. Further studies concerned with the optimum concentration of NaF that has an effect in vivo are necessary.

• Korean Journal of Social Welfare
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• v.66 no.4
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• pp.181-205
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• 2014

The purpose of this study is to analyze the process of growth of parental empowerment of the family of the children with development disabilities in an online parental community. For this purpose, 250 posts were selected from a web-forum of an online-community(internet CAFE) for patients with developmental disabilities in a Korean portal site. In addition, the selected posts were analyzed based on the grounded theory method. The results showed that the parents with high risk children for developmental disabilities interacted with each other in short answers, self-addressing, and discussion type interactions under the causal condition in which the subject parents were in need of help and sympathy. The factors that significantly affected the focus event, which is the interactive communication between the posters of the original threads and replies, included the moderating conditions based on whether the conversation was respectful, friendly, or for general evaluation, as well as the contextual condition of exclusive attitudes. The strategies of the interactions were composed of two categories of self-reflections and sharing through a human relationship. The results of these interactions were either further interactions (sharing) or shying away. With regard to the process of reinforcing the collective empowerment of the family, the 'determination,' 'tips,' and 'empathy' models were used for the explanation of the process. Lastly, we discovered that trust, support, continuous interactions, specific and practical information, as well as provision of diversified perspectives through collective experiences are necessary to achieve such improvement of collective family empowerment.

• Informatization Policy
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• v.24 no.4
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• pp.3-16
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• 2017

With the development of social media services in the era of Web 2.0, the public opinion formation site has been partially shifted from the traditional mass media to social media. This phenomenon is continuing to expand, and public opinions on government polices created and shared on social media are attracting more attention. It is particularly important to grasp public opinions in policy formulation because setting up educational policies involves a variety of stakeholders and conflicts. The purpose of this study is to explore public opinions about education-related policies through an empirical analysis of social media documents on education policies using opinion mining techniques. For this purpose, we collected the education policy-related documents by keyword, which were produced by users through the social media service, tokenized and extracted sentimental qualities of the documents, and scored the qualities using sentiment dictionaries to find out public preferences for specific education policies. As a result, a lot of negative public opinions were found regarding the smart education policies that use the keywords of digital textbooks and e-learning; while the software education policies using coding education and computer thinking as the keywords had more positive opinions. In addition, the general policies having the keywords of free school terms and creative personality education showed more negative public opinions. As much as 20% of the documents were unable to extract sentiments from, signifying that there are still a certain share of blog posts or tweets that do not reflect the writers' opinions.

• Journal of the Korean Society for information Management
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• v.32 no.4
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• pp.77-106
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• 2015

By document co-citation analysis with Korean Citation Index (KCI) data, this study accurately identified the research fronts and hot topics in Korean library and information science (LIS) from 2004 to 2013. 159 core papers in LIS domain and their citations are scraped manually from Korean Citation Index web site. In the cluster analysis and network analysis, 159 core papers were grouped into 27 clusters with multiple papers and 8 singlton clusters. Among the 27 clusters which have multple papers, 'LIS education' cluster was the largest with 16 core papers, and 'citation analysis & intellectual structure analysis' cluster had the strongest citation impact according to the ehs-index. Closer observation of the citations to the core papers in each research front showed that 67.5% of the citations were made by LIS research papers and 32.5% of the citations were made by non-LIS research papers. Considering the share of citations and the citation impact growth index, 'local documentation', 'citation analysis & intellectual structure analysis', and 'research trends analysis' were identified as the most emerging research front in Korean library and information science. The analytical methods used in this study have great potential in discovering the characteristics of research fronts in Korean interdisciplinary research domains.

• Journal of Sasang Constitutional Medicine
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• v.26 no.4
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• pp.339-349
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• 2014

Objectives This study was performed to make a short-form of Sasang Constitution Questionnaire for Patient(SSCQ-P). Methods In order to select important questions of SSCQ-P, we got advice from 10 professors of Oriental Medicine. As a result, we chose 37 questions. In addition, we selected 69 questions which had been used more than 12 times in SSCQ-P as the variable. We used some statistical methods to reduce questions. Finally, a total of 40 questions were selected. To find diagnostic accuracy rate of this short-form, discriminant analysis was performed. We used 1378 cases which was collect ed from February 2008 to June 2013 by online system(Sasang-medi data which has selected by web site, http://www.sasangmedi.or.kr), and 68 cases which was collected from November 2006 to September 2007 by the research "Construction of a biological information collection system for the Constitutional scientific diagnosis"(Korea Constitutional Multicenter Bank data, KCMB data) Results We made a short-form of SSCQ-P consisting of 40 questions. Diagnostic accuracy rate of short-form is 66.18% using Sasang-medi data, and 42.65% using KCMB data. Conclusions More cases are needed to improve the diagnostic accuracy rate of this short-form.