• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.1-11
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• 2009

XQuery query proposed by W3C is one of the standard query languages for XML data and is widely accepted by many applications. Therefore the studies for efficient Processing of XQuery query have become a topic of critical importance recently and the optimization of XQuery query is one of new issues in these studies. However, previous researches just focus on the optimization techniques for a specific XML data management system and these optimization techniques can not be used under the any XML data management systems. Also, some previous researches use predefined XML data structure information such as XML schema or DTD for the optimization. In the real situation, however applications do not all refer to the structure information for XML data. Therefore, this paper analyzes only a XQuery query and optimize by using itself of the XQuery query. In this paper, we propose 3 kinds of optimization method that considers the characteristic of XQuery query. First method removes the redundant expressions described in XQuery query second method replaces the processing order of operation and clause in XQuery query and third method rewrites the XQuery query based on FOR clause. In case of third method, we consider FOR clause because generally FOR clause generates a loop in XQuery query and the loop often rises to execution frequency of redundant operation. Through a performance evaluation, we show that the processing time for rewritten queries is less than for original queries. also each method in our XQuery query optimizer can be used separately because the each method is independent.

• The Journal of Engineering Geology
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• v.33 no.2
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• pp.323-334
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• 2023

The vast volumes of data that are generated during site characterization and associated research for the disposal of high-level radioactive waste require effective data management to properly chronicle and archive this information. The Swedish Nuclear Fuel and Waste Management Company, SKB, established the SICADA database for site selection, evaluation, analysis, and modeling. The German Federal Company for Radioactive Waste Disposal, BGE, established ArbeitsDB, a database and document management system, and the ELO data system to manage data collected according to the Repository Site Selection Act. The U.K. Nuclear Waste Services established the Data Management System to manage any research and survey data pertaining to nuclear waste storage and disposal. The U.S. Department of Energy and Office of Civilian Radioactive Waste Management established the Technical Data Management System for data management and subsequent licensing procedures during site characterization surveys. The presented cases undertaken by these national agencies highlight the importance of data quality management and the scalability of data utilization to ensure effective data management. Korea should also pursue the establishment of both a data management concept for radioactive waste disposal that considers data quality management and scalability from a long-term perspective and an associated data management system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.191-197
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• 2009

This study choose the Criteria by conducting survey questionnaire of expertise, ANP analysis, and reviewing literature to samples of School Zone in a synthetic and reasonable way. It draws the estimating factors including a variety of existing aspects (user, facility, operation and management, and education and institution) from the analyses and applies ANP to reflect the decision making process. The results show as follows: first, first level of weights presents proportion of 'facility' and 'user' takes 65% of total weights. It implies that the facility protects children from obstacles is the top priority of the settings. second, the second level of weights present similar importance with the first level. Facility management, road to school, surroundings, safety facility, decelerating facility hold approximately 72% of overall levels. This indicates that improving and repairing surroundings, and safety and decelerating facility are the first priority to consider. These estimating indicators will be properly utilized to rationally appoint prevention zone with reflecting various factors and social class.

• Journal of the Korean earth science society
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• v.44 no.3
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• pp.236-252
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• 2023

Both Earth science II and Korean geography textbooks emphasize the importance of content related to 'geology of the Korean Peninsula'. This study aimed to analyze the differences in the content related to the 'geology of the Korean Peninsula' presented in the textbooks, and to find out whether these differences are consistent with the latest scientific knowledge in any inconsistencies are found. For this purpose, seven textbooks (four Earth science II and three Korean geography) published under the 2015 revised curriculum were selected as the subject of analysis, and the difference in the description of the tectonic provinces of the Korean Peninsula, geologic time scale, and explanatory texts of geological characteristics between Earth science II and Korean geography textbooks were compared. As a result of the analysis, there are some cases of inconsistencies between Earth science II and Korean geography textbooks in terms of terminologies, names, and distribution ranges related to the tectonic provinces of the Korean Peninsula. The Korean geography textbooks had inconsistencies in the geochronologic data of the rocks as they cited outdated data. In addition, inconsistencies were found in the explanatory texts describing the 'distribution of rocks on the Korean Peninsula', 'characteristics of the Pyeongan Supergroup', and 'great hiatus of the Paleozoic Era'. Both Earth science and Geography have many concepts in common, therefore, effort is needed to minimize the differences in content. It is important to select the content appropriately which should reflect the latest scientific knowledge and presents the concepts consistently.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.91-101
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• 2023

In this study, we estimated the concentration of chlorophyll-a (Chl-a) using hyperspectral water surface reflectance in an inland weir (Baekjae weir) and estuarine reservoir (Namyang Reservoir) for monitoring the occurrence of algae in freshwater in South Korea. The hyperspectral reflectance was measured by aircraft in Baekjae Weir (BJW) from 2016 to 2017, and a drone in Namyang Reservoir (NYR) from 2020 to 2021. The 30 reflectance bands (BJW: 400-530, 620-680, 710-730, 760-790 nm, NYR: 400-430, 655-680, 740-800 nm) that were highly related to Chl-a concentration were selected using permutation importance. Artificial neural network based Chl-a estimation model was developed using the selected reflectance in both water bodies. And the performance of the model was evaluated with the coefficient of determination (R²), the root mean square error (RMSE), and the mean absolute error (MAE). The performance evaluation results of the Chl-a estimation model for each watershed was R²: 0.63, 0.82, RMSE: 9.67, 6.99, and MAE: 11.25, 8.48, respectively. The developed Chl-a model of this study may be used as foundation tool for the optimal management of freshwater algal blooms in the future.

• The Mathematical Education
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• v.62 no.1
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• pp.151-173
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• 2023

In this study, we explored factors that affect high school student's affective attitude on mathematics with respect to the school mathematics instructoin, school mathematics assessment, mathematics textbook, private mathematics education, college entrance and career, and social atmosphere. Considering students' grade, major, academic level, gender, and school location, 1,029 high school students participated in the survey. To analyze the survey results, descriptive statistics, t-test, ANOVA, and chi-square test were conducted using SPSS ver 29.0. Results are as follows. First, generally, college entrance and career and school mathematics instruction affected students' affective attitude on mathematics. Second, according to student's academic level and gender, there was a statistically significant difference in the factors affecting the affective attitude on mathematics. Third, according to students' background, there was a statistically significant difference in students' responses to sub-categories of each factor. We suggested that to improve student's affective attitude on mathematics, diversity of the school mathematics instruction, improvement of the mathematics textbook, student's appropriate participation in the private mathematics education, improvement of student's perception of the utilization of the mathematics in the future and the importance of the mathemaitcs in the society, and parents' emotional support are needed.

• Analytical Science and Technology
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• v.21 no.4
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• pp.338-343
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• 2008

Extraction of DNA from skeletal material is of great importance in the identification of human remains, but is particularly difficult because the high amount of microbial DNA was often co-extracted with human bone DNA. We found that a phenol/chloroform extraction, followed by ultrafiltration, and cleanup by via the $QIAquick^{(R)}$ PCR purification kit yields higher amounts of human genomic DNA compared with extraction by the column affinity $method^{(R)}$ alone. Ultrafiltration extraction of human DNA from ten exhumed bone samples yielded $0.041-1.120ng/{\mu}L$ DNA (mean = $0.498ng/{\mu}L$ DNA), and purification using the column affinity resulted in $0.016-0.064ng/{\mu}L$ DNA (mean = $0.034ng/{\mu}L$ DNA). Although the STR genotyping by the column affinity method was partially successful, all DNA samples by the ultrafiltration method produced full profiles from the multiplex PCR. The efficiency of STR genotyping was in accordance with the amounts of the human DNA extracted.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.499-509
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• 2006

Precast concrete deck has many advantages comparing with the in-situ concrete deck, and has been successfully applied to replacement of the deteriorated decks and to the newly constructed highway bridges in domestic region. In order to apply the precast decks into the railway bridges, however, differences of the load characteristics between the highway and the railway should be properly taken into account including the train load, longitudinal force of the continuous welded rail, acceleration or braking force, temperature change and shrinkage. Proper level of the longitudinal prestress of the tendons that can ensure integrity of the transverse joints in the deck system is of a primary importance. To this aim, the longitudinal tensile stresses induced by the design loads are derived using three-dimensional finite element analyses for the frequently adopted PSC composite girder railway bridge. The effect of the temperature change is also investigated considering the design codes and theoretical equations in an in-depth manner. The estimated proper prestress level to counteract those tensile stresses is above 2.4 MPa, which is similar to the case of the highway bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.43-52
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• 2006

Despite several constitutive models have been proposed and applied, it is still difficult to choose a suitable model and to estimate adequate analysis parameters. Furthermore, a cyclic shear behavior under the volume change caused by the seepage is more complex. None of the constitutive model is available at present in the expression of the cyclic behavior of soil under an additional volume change condition by seepage. Therefore, a new geotechnical hybrid simulation system which can control the pore water immigration was developed. The system enables a quantitative evaluation of the residual deformation such as lateral spreading and settlement caused by the liquefaction. The seismic responses in a one-dimensional slightly inclined multilayered soil system are taken into consideration, and the soils are governed by both equation of motion and the continuity equation. Furthermore, the estimation and the selection of the soil parameter for the representation of the strong nonlinearity of the material are not required, because soil behaviors under the earthquake motions are directly introduced instead of a numerical soil constitutive model. This paper presents the concept and specifications of the system. By applying the system to an example problem, the permeability effect on the seismic response during cyclic shear is studied. The importance of the volume change characteristics of sandy soil during and after cyclic shear is shown in conclusion.

• 한국노년학
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• v.29 no.3
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• pp.953-970
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• 2009

The successful aging paradigm suggests that the elderly keep their social ties and actively participate in various activities in later life. Many Korean studies on aging, however, have overlooked the importance of various social activities and relationships beyond kinship. This article aims to investigate the perceived social activities among Korean elders to comprehend the subjectivity of successful aging. 613 respondents, over 50 years old, are selected from a national survey data which was collected by face-to-face interview based on the structured questionnaire. The respondents are classified into pre old (50-64), young old (65-74), old old (over 75). Major findings are as follows. The social activities are grouped into two sub-categories: 'relational activity' and 'productive activity'. The activity types are different by the age cohorts. Various activities are considered in terms of one's needs or motivations, and properly chosen based on the subjective evaluation during life course. Both demographic variables such as sex, area and social context variables such as marital status, living-together show influence on the activity type choices. Plans for later life and work ethics are important as well. Policies regarding social participation emphasizing productivity should positively consider relational motives, as perceived by the Korean elderly.