• Analytical Science and Technology
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• v.19 no.1
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• pp.73-85
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• 2006

Blood serum concentrations of polychlorinated biphenyls (PCBs) were measured in employees who worked at a municipal solid waste incinerator (MSWI), members of residential community who lived near the MSWI (<0.3km) and members of residential community lived far from the MSWI (>10 km). Human blood serum samples were analyzed for all PCB congeners using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The mean levels of total PCBs and dioxin-like PCBs in 87 serum samples were 242.77 ng/g lipid and 8.83 TEQ pg/g lipid, respectively. The PCB homologue profiles showed that penta-, hexa-, hepta-chlorinated biphenyls contributed more than 80% of the total PCBs concentration. The most abundant congeners were PCB153, PCB138, PCB180, PCB187, PCB118. A statistical analysis was performed to determine whether there were significant correlations between PCB concentrations and specific variables such as age, gender, smoking habits, occupation, BMI (Body Mass Index) and time of residence. As a result, the age was found to be strongly correlated with serum PCB concentrations. In addition, there were strong correlations between total PCBs and PCB153 (r=0.93, p<.0001), dioxin-like PCBs and PCB118 (r=0.98, p<.0001). So these two congeners are satisfactory indicators for total PCB concentrations and dioxin-like PCBs in human blood respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.210-217
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• 2016

Purpose: The aim of this study was to evaluate the marginal and internal adaptation of monolithic zirconia restoration made without physical model by digital intraoral scanner. Materials and methods: A prospective clinical trial was performed on 11 restorations as a pilot study. The monolithic zirconia restorations were fabricated after digital intraoral impression taking by intraoral scanner (TRIOS, 3shape, Copenhagen, Denmark), computer-aided designing, and milling manufacturing process. Completed zirconia crowns were tried in the patients' mouth and a replica technique was used to acquire the crown-abutment replica. The absolute marginal discrepancy, marginal gap, and internal gap of axial, line angle, and occlusal part were measured after sectioning the replica in the mesiodistal and buccolingual direction. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U test (${\alpha}=.05$). Results: From the adaptation analysis by replica, the statistically significant difference was not found between mesiodistal and buccolingual sections (P>.05), but there was significant difference among the measurement location (P<.01). The amount of absolute marginal discrepancy was larger than those of marginal gap and internal gap (P<.01). Conclusion: Within the limitations of this study, the adaptation accuracy of model-free monolithic zirconia restoration fabricated by intraoral scanner exhibited clinically acceptable result. However, the margin of zirconia crown showed tendency of overcontour and cautious clinical application and follow up is necessary.

• Journal of Information Management
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• v.42 no.2
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• pp.151-165
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• 2011

Patent information as the innovative index for activity of industry, science and technology reflects the inventive outcome of the nation, region, technology, or company etc.. and is able to be used as a tool evaluating the R&D product and technology diffusion. In this study, the index for analysing the productivity, innovation, and activity of the technology is provided to evaluate the technology in fields of the pharmaceutic, transport, biotechnology, textile, construction, machine parts, information media, and electric/telecommunication, which are becoming the national core technology. As a result of analysis, the technology activity in fields of the construction, pharmaceutic, and biotechnology shows a growing trend which reflect the interest in the quality and the extension of the life, but vice versa in fields of the textile, and information media. The innovation index in fields of the construction, pharmaceutic, and biotechnology index more than average, but vice versa in fields of the information media and electric/telecommunication. In case of technology productivity, more than 2 patentees are included in one patented technology. It has been determined that the technology productivity is decreased because of an increasing number of researcher participating the technology development, which is the recent trend of technology advancement.

• 전자공학회논문지 IE
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• v.47 no.1
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• pp.22-33
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• 2010

The main purpose of this study was to develope a reflective journal and examine its effects on student's academic achievement and self-regulated learning strategies. For this study, 'a structured reflective journal' was designed through the steps of systems approach with the purpose of enhancing student's academic achievement and self-regulated learning strategies, especially meta-cognition and critical thinking. The reflective journal used in this study contained the constructive elements of (1) self-evaluation with 5 likert scale, (2) learning essay, (3) dialogue with peers, and (4) dialogue with professor. A total of 94 freshmen enrolled in one of two sections of the engineering courses(theory-based class and experiment and practice-based class) participated in the study for 8 weeks. A pre-test-post-test design was used to examine the effects of the application of reflective journal on student's achievement and self-regulated learning strategies. For the result, analysis of covariance was conducted to determine whether there were any academic achievement differences and self-regulated learning strategy differences. The results suggested that students were taking advantages of the reflective journal, and there were statistically significant differences in academic achievement in the experiment and practice-based class and self-regulated learning strategies in both classes.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.185-191
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• 2021

The purpose of this study is to develop middle school English classes using Problem-Based Learning(PBL) based on flipped learning and to examine its effects. Recently, various attempts to combine flipped learning and PBL have been made; however, many studies have not been applied to middle and high school curriculums yet. The attempt of this study is expected to have theoretical and practical significance. The instructional model was derived from the review of previous studies, and the development of instructional program followed the general design procedure(analysis-design-development-implement-evaluation), and its validity was secured with the advice of related experts. To verify the effectiveness of the program, the English academic achievement test and the English key competency test were conducted before and after the program. Changes in English academic achievement were analyzed by the paired-sample t-test, and the effect of key competency and the level of achievement test performance (high vs, low) on the pre-post score change was analyzed by the mixed effects repeated measures ANOVA. As a result of the analysis, both academic achievement and key competencies increased, and the low-level students in the pre-academic achievement test showed more improvements. In conclusion, the PBL class based on flipped learning is effective in improving the English academic achievement and key competencies of middle school students, and in particular, it is shown to be an effective teaching method for students with low academic achievement.

• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.194-209
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• 2023

This study aims to present implications for the appropriate establishment and development of a science-authorized textbook system through an understanding of the process of selecting science-authorized textbooks and analyzing the perception of teachers. Toward this end, this study conducted interviews with five elementary school teachers who participated in the science textbook selection process, surveys on 32 teachers, and analysis on the authors of the textbooks. The result demonstrated, first, that the "opinion gathering" stage was the most important one, and a council was formed in consideration of career and major. Moreover, the evaluation standard was reorganized and used according to the situation of the school. Second, in the process of opinion gathering, the teachers used a method for reviewing the entire textbook for each teacher. Inquiry activities and textbook composition (readability) were crucially considered as internal factors, and teaching and learning materials, such as videos, were deemed extremely important as external factors. The variable of the author, which is an indicator of the reliability and expertise of textbooks, was also recognized as vital. Third, the deliberation by the School Committee and the report by the principal were recognized as the administrative final step after selection. Finally, selecting the most suitable textbooks for each grade group was recognized as more important than arbitrarily unifying textbooks for the third and fourth grades and for the fifth and sixth grades.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.4
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• pp.275-286
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• 2014

This study evaluated the evolution stage and origin of chemical components of 12 boreholes at crystalline bedrock using multivariate statistical and groundwater quality analyses. Groundwater types are mostly belonged to Na(Ca)-$HCO_3$ and Ca-$HCO_3$ types, indicating that directly reaction of cation exchange ($Ca^{2+}{\rightarrow}Na^+$) prevailed. The degree of groundwater evolution is included the range from low to intermediate stage based on field and laboratory analytical conditions. As a result of multivariate statistical analysis, a typical indicator of groundwater contamination, $NO_3$-, has the positive correlation with $Na^+$ and $Cl^-$. The origin of sea spary ($Cl^-$) has the positive correlation with $Na^+$, $SO{_4}^{2-}$, $Mg^{2+}$, and $K^+$, while not correlation with $Ca^{2+}$, $Fe^{2+}$, $HCO_3{^-}$, $F^-$, and $SiO_2$. The concentration of $Cl^-$ and $NO_3{^-}$ belongs to general quality of groundwater and not exceeds over the Korean standard for drinking water. And the negative values of saturation index of minerals are calculated with chemical components in groundwater. Therefore, most of chemical components of groundwater in the study area are originated from natural process between rock and groundwater, whereas some of components are derived from sea spary and anthropogenic sources related to agricultural activities.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5195-5200
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• 2014

Background: The purpose of this study was to analyze our series of liver resections for metastatic colorectal carcinoma (mCRC) to determine prognostic factors affecting survival and to evaluate the potential roles of neoadjuvant or adjuvant chemotherapy. Materials and Methods: Ninety-nine patients who underwent metastasectomy for liver metastases due to colorectal cancer at the Department of Medical Oncology, 9 Eylul University Hospital between 1996 and 2010 were evaluated in this study. The patients were followed through July 2013. Demographic, perioperative, laboratory, radiological and chemotherapy as well as survival data were obtained by retrospective chart review. Results: In 47 (47.5%) patients, liver metastases were unresectable at initial evaluation; the remaining 52 (52.5%) patients exhibited resectable liver metastases. Simultaneous hepatic resection was applied to 52 (35.4%) patients with synchronous metastasis, whereas 5 (64.5%) patients underwent hepatic resection after neoadjuvant chemotherapy. Forty-two patients with metachronous metastasis underwent hepatic resection following neoadjuvant chemotherapy. R0 resection was obtained in 79 (79.8%) patients. A second hepatectomy was performed in 22 (23.2%) patients. Adjuvant chemotherapy was given to 85 (85.9%) patients after metastasectomy. The median disease-free and overall survivals after initial metastasectomy were 12 and 37 months, respectively, the 1-year, 3-year and 5-year disease-free survival (DFS) and overall survival (OS) rates being 46.5%, 24.3% and 17.9%and 92.3%, 59.0% and 39.0%, respectively. On multivariate analysis, the primary tumor site, tumor differentiation, resection margin and DFS were independent factors predicting better overall survival. Conclusions: In selected cases, hepatic metastasectomy for mCRC to the liver can result in long-term survival. Neoadjuvant chemotherapy did not exert a positive effect on DFS or OS. Adjuvant chemotherapy also did not appear to impact DFS and OS.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.101-119
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• 2018

In this study, we analyzed long-term measurements and air quality simulation results of four criteria air pollutants ($PM_{10}$, $O_3$, $NO_2$, and $SO_2$) for 10 years, from 2006 to 2015, with emphasis on trends of annual variabilities. With the observation data, we conducted spatial interpolation using the Kriging method to estimate spatial distribution of pollutant concentrations. We also performed air quality simulations using the CMAQ model to consider the nonlinearity of the secondary air pollutants such as $O_3$ and the influence of long-range transport. In addition, these simulations are used to deduce the effect of long-term meteorological variations on trends of air quality changes because we fixed the emissions inventory while changing meteorological inputs. The nation-wide inter-annual variability of modeled $PM_{10}$ concentrations was $-0.11{\mu}g/m^3/yr$, while that of observed concentrations was $-0.84{\mu}g/m^3/yr$. For the Seoul Metropolitan Area, the inter-annual variability of observed $PM_{10}$ concentrations was $-1.64{\mu}g/m^3/yr$ that is two times rapid improvement compared to other regions. On the other hand, the inter-annual variability of observed $O_3$ concentrations is 0.62 ppb/yr which is larger than the simulated result of 0.13 ppb/yr. Magnitudes of differences between the modeled and observed inter-annual variabilities indicated that decreasing trend of $PM_{10}$ and increasing trend of $O_3$ are more influenced by emissions and oxidation states than meteorological conditions. We also found similar patterns in $NO_2$. However, $NO_2$ trends showed greater regional and seasonal differences than other pollutants. The analytic approach used in this study can be applicable to estimate changes in factors determining air quality such as emissions, weather, and surrounding conditions over a long term. Then analysis results can be used as important data for air quality management planning and evaluation of the chronic impact of air quality.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.171-178
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• 2020

Amid public's growing interest on garden and more leisure time of modern life-style, there is an effort by the government to utilize forest as public garden. In order to utilize forests as pubic garden, a new concept of "Forest Garden" should be defined and introduced first. Furthermore, introducing a new concept requires academically analyzing values of a new concept before a new concept is widely used. Thus, we aimed to clarify the concept of forest garden by conducting Delphi technique research and factor-analysis of survey results. More specifically, delphi technique research was conducted to extract composition elements and explanation elements of forest garden. Factor analysis was conducted on the top 25 elements and 5 values were extracted as a result. They are form, scenery, ecology, history/cuture and usefulness which are essential values required of forest garden. Forest garden should have all of 5 values and be capable of function as both forest and garden which would also need continuous maintenance. We believe this study is the first one to establish definition of forest garden and more specific and realistic definitions need to be built through continuous research, 000 experiment and on-site evaluation. We also believe that this study will serve as foundation for further efforts in building forest garden in various space and in defining proper concept of forest garden.