• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.118-125
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• 2019

Swimming performance of fish is an important factor in the survival of fish. Also, swimming performance of fish is used in the form of habitat, or as a condition to consider when creating a fish ladder. However in Korea, researches in swimming performance of Korean freshwater fish were scarce and inadequate in some part, thus fish ladders were installed without considering their swimming performance. Therefore, in this study, we measured swimming performance of 4 Korean freshwater fish species to consider importance of swimming performance test. The fish used in this study were Carassius auratus, Zacco koreanus, Gnathopogon strigatus, Acheilognathus lanceolata intermedia species which was collected during October to November, 2018 at Geum River, and measurement for swimming speed of each fish was done by using $Loligo^{(R)}$ System, swim tunnel respirometer in January to February of 2019. The average value of the burst critical swimming speed ($U_{crit}$) for each species was $0.8{\pm}0.04m\;s^{-1}$ for C. auratus, $0.77{\pm}0.04m\;s^{-1}$ for Z. koreanus, $0.95{\pm}0.04m\;s^{-1}$ for G. strigatus, $0.73{\pm}0.03m\;s^{-1}$ for A. lanceolata intermedia and the average value of prolonged critical swimming speed was $0.54m\;s^{-1}$ for C. auratus, $0.67m\;s^{-1}$ for Z. koreanus, $0.7m\;s^{-1}$ for G. strigatus, $0.54m\;s^{-1}$ for A. lanceolata intermedia. Since the fish used in this experiment were collected from a small part of the water system in Korea and there were only 4 species, they were not enough to represent the species that inhabit the entire Korean water system. It will be necessary to continue evaluating the swimming performance of other freshwater species in Korea.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.31-48
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• 2019

The artificial ground freezing (AGF) method is a groundwater cutoff and/or ground reinforcement method suitable for constructing underground structures in soft ground and urban areas. The AGF method conducts a freezing process by employing a refrigerant circulating through a set of embedded freezing pipes to form frozen walls serving as excavation supports and/or cutoff walls. However, thermal expansion of the pore water during freezing may cause excessive deformation of the ground. On the other hand, as the frozen soil is thawed after completion of the construction, mechanical characteristics of the thawed soil are changed due to the plastic deformation of the ground and the rearrangement of soil fabric. This paper performed a field experiment to evaluate the freezing rate of marine clay in the application of the AGF method. The field experiment was carried out by circulating liquid nitrogen, which is a cryogenic refrigerant, through one freezing pipe installed at a depth of 3.2 m in the ground. Also, a piezo-cone penetration test (CPTu) and a lateral load test (LLT) were performed on the marine clay before and after application of the AGF method to evaluate a change in strength and stiffness of it, which was induced by freezing-thawing. The experimental results indicate that about 11.9 tons of liquid nitrogen were consumed for 3.5 days to form a cylindrical frozen body with a volume of about $2.12m^3$. In addition, the strength and stiffness of the ground were reduced by 48.5% and 22.7%, respectively, after a freezing-thawing cycle.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.65-71
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• 2019

With regard to current Neck CT, Bismuth shielding boards are often being used to reduce exposure to superficial organs such as the thyroid. However, beam hardening often occurs near superficial organs with Bismuth shielding boards and variations in CT Number, Noise, and Uniformity values occur severely. This study looked into the usefulness of shielding boards made from aluminum and silicone that can be easily obtained and have good machinability by comparing them to the existing Bismuth shielding board. An Aluminum 7.3mm and a Silicone 21.5mm were made with shielding ratios similar to that of the Bismuth(0.06 mmPb). TLD (TLD-100) was placed on the thyroid area of the Phantom (RS-108T) and 5 doses were measured for each. To compare image quality, CT Number and Noise variations in axial images of the thyroid area in Neck CT images were compared. Also, variations in CT Number, Noise, and Uniformity were measured in the AAPM phantom images and compared. In the results, when thyroid doses for each shielding board were compared, the Bismuth shielding board showed a 14% reduction, the Silicone 21.5mm showed a 15% reduction, and the Aluminum 7.3mm showed a 13% reduction compared to the Non-Shield. Statistically, there were no significant differences in comparison with the Bismuth shielding board. In CT Number variations of thyroid area images, variations were largest for the Bismuth shielding board. With Uniformity evaluations of the AAPM phantom, the Bismuth shielding board was found unsuitable and the Aluminum 7.3mm and Silicone 21.5mm satisfied the acceptance criteria. Research results show that the Aluminum 7.3mm and Silicone 21.5mm have a similar shielding ratio to the high-priced Bismuth shielding board that is currently being used clinically and in comparison tests of CT Number attenuation coefficient variations, Noise, and Uniformity which are phantom image evaluation items, they proved to be better than Bismuth shielding boards. If various shielding boards are made using aluminum and silicone, sized appropriately for superficial organs, it would be useful in decreasing patient doses.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.111-118
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• 2019

Chest digital tomosynthesis has become a practical imaging modality because it can solve the problem of anatomy overlapping in conventional chest radiography. However, because of both limited scan angle and finite-size detector, a portion of chest cannot be represented in some or all of the projection. These bring a discontinuity in intensity across the field of view boundaries in the reconstructed slices, which we refer to as the truncation artifacts. The purpose of this study was to reduce truncation artifacts using a weighted normalization approach and to investigate the performance of this approach for our prototype chest digital tomosynthesis system. The system source-to-image distance was 1100 mm, and the center of rotation of X-ray source was located on 100 mm above the detector surface. After obtaining 41 projection views with ${\pm}20^{\circ}$ degrees, tomosynthesis slices were reconstructed with the filtered back projection algorithm. For quantitative evaluation, peak signal to noise ratio and structure similarity index values were evaluated after reconstructing reference image using simulation, and mean value of specific direction values was evaluated using real data. Simulation results showed that the peak signal to noise ratio and structure similarity index was improved respectively. In the case of the experimental results showed that the effect of artifact in the mean value of specific direction of the reconstructed image was reduced. In conclusion, the weighted normalization method improves the quality of image by reducing truncation artifacts. These results suggested that weighted normalization method could improve the image quality of chest digital tomosynthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.127-133
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• 2019

Purpose: The purpose of present study was to investigate fracture strength and mode of failure of endodontically treated teeth restored with metal cast post-core system, prefabricated fiber post system, and newly introduced polyetherketoneketone (PEKK) post-core system. Materials and methods: A total of 21 mandibular premolar were randomly grouped into 3 groups of 7 each according to the post material. Group A was for metal cast post core; Group B for prefabricated glass fiber post and resin core; and Group C for milled PEKK post cores. All specimens were restored with metal crown. The fracture strength of each specimen was measured by applying a static load of 135-degree to the tooth at 2 mm/min crosshead speed using a universal testing machine. After the fracture strength measurement, the mode of failure was observed. The results were analyzed using Kruscal-Wallis test and post hoc Mann-Whitney U test at confidence interval ${\alpha}=.05$. Results: Fracture resistance of PEKK post core was lower than those of cast metal post and fiber reinforced post with composite resin core. In the aspect of fracture mode most of the root fracture occurred in the metal post core, whereas the post detachment occurred mainly in the fiber reinforced post. In the case of PEKK post core, teeth and post were fractured together. Conclusion: It is necessary to select appropriate materials of post for extensively damaged teeth restoration and clinical application of the PEKK post seems to require more research on improvement of strength.

• Journal of Gynecologic Oncology
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• v.29 no.6
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• pp.100.1-100.13
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• 2018

Objective: To investigate survival outcomes in endometrioid endometrial cancer (EEC) patients with single vs. multiple positive pelvic lymph nodes. Methods: We performed a retrospective evaluation of all consecutive patients with histologically proven International Federation of Gynecology and Obstetrics (FIGO) stage IIIC1 EEC who underwent primary surgical treatment between 2004 and 2014 at seven Italian gynecologic oncology referral centers. Patients with pre- or intra-operative evidence of extra-uterine disease (including the presence of bulky nodes) and patients with stage IIIC2 disease were excluded, in order to obtain a homogeneous population. Results: Overall 140 patients met the inclusion criteria. The presence of >1 metastatic pelvic node was significantly associated with an increased risk of recurrence and mortality, compared to only 1 metastatic node, at both univariate (recurrence: hazard ratio [HR]=2.19; 95% confidence interval [CI]=1.2-3.99; p=0.01; mortality: HR=2.8; 95% CI=1.24-6.29; p=0.01) and multivariable analysis (recurrence: HR=1.91; 95% CI=1.02-3.56; p=0.04; mortality: HR=2.62; 95% CI=1.13-6.05; p=0.02) and it was the only independent predictor of prognosis in this subset of patients. Disease-free survival (DFS) and disease-specific survival (DSS) were significantly longer in patients with only 1 metastatic node compared to those with more than 1 metastatic node (p=0.008 and 0.009, respectively). Conclusion: The presence of multiple metastatic nodes in stage IIIC1 EEC represents an independent predictor of worse survival, compared to only one positive node. Our data suggest that EEC patients may be categorized according to the number of positive nodes.

• Journal of Korean Home Economics Education Association
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• v.33 no.3
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• pp.85-105
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• 2021

The purpose of this study is to develop and implement cooperative consumption education programs using design thinking in middle school home economics education classes to understand the impact on students' cooperative problem solving competency. Accordingly, a cooperative consumption education program based on design thinking was developed according to the ADDIE model, and the evaluation was conducted on a total of 25 students. The results of the study were as follows. First, based on prior research, we developed a consumption education program based on D. school's design thinking process under the theme of 'Creating a Shared School' for the practice of cooperative consumption. As a result of expert validity verification of the teaching/learning course plan and workbook for the eight sessions, the average question was 4.72 (out of 5 points) and the average CVI was 0.93, indicating that the content validity and field suitability were excellent. Second, to summarize the results achieved from the implementation of the cooperative consumption education program, the pre-/post-test using the revised and supplemented cooperative problem-solving competency tool, and the open-ended survey, It was confirmed that the developed program had a significant effect on improving not only the students' knowledge and perceived necessity for cooperative consumption along with the awareness of practice, but also the cooperative problem-solving competency. As a follow-up study, we propose to expand the research to a wider audience, and to further conduct research and develop programs applied with design thinking in home economics curriculum and in consumer competency development. This study confirmed that cooperative consumption education programs using design thinking are effective in improving youth's cooperative problem-solving competency and is meaningful in that they developed consumption education programs under the theme of 'cooperative consumption' in response to changing consumer education needs.

• Journal of Christian Education in Korea
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• v.66
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• pp.75-112
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• 2021

This study is purposed to prepare students in theological universities so that they contribute to their faith community as well as the broader social community in future through developing a practical course model for education of character formation. Facing the challenge of a high-tech revolution being progressed globally in this period, theological seminaries as the Christian-affiliated institute of higher education see the necessity to nurture their learners' competency of holistic personality comprehending cognitive, affective, behavioral, and more spiritual maturity as well as specialty in each subject matter. The holistic character capability of seminarians is closely related not only to their own self-realization, but also social community's well-being. This research had the following content and results. Chapter 1 brought up a subject to educational needs of the holistic character formation in the theological seminaries to meet the rapidly changing times. Chapter 2 considered the importance of character formation in the curriculum of the universities and theological seminaries in the times of high-tech revolution through the literature reviews related to. Chapter 3 clarified the elements of character education to be placed emphasis on theological seminaries and established the way of course planning. Chapter 4, using a course of Christian social education for illustration, described in order the whole process of course planning comprehending the need of planning, description of course concept, establishment and definition of learning outcomes, organization of learning experience(course content), teaching-learning activities, evaluation of learning outcome, and course improvement, which was visualized with the chart of the process of course design. Also, it provided a practical illustration of the conceptual map, an outline of content and an organization of units, and scope-sequence chart. Finally, chapter 5 gave an syllabus example in an integrative and digestive form as the course plan to be distributed to the students, which is the final result produced through the whole process of course planning. This research is intended not to present a overall curriculum planning of the university-level in the theological seminaries, but to develop a course-level curriculum focused on the formation of character. The author hope that this study would be used as a guideline in developing a course model to nurture the capability of the learners' holistic character.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.687-694
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• 2020

Two oxidizing agents (KMnO4, H2O2), and one neutralizing agent (NaOH) were applied to evaluate Mn removal in mine drainage. A Mn2+ solution and artificial mine drainage were prepared to identify the Fe2+ influence on Mn2+ removal. The initial concentrations of Mn2+ and Fe2+ were 0.1 mM and 1.0 mM, respectively. The injection amount of oxidizing and neutralizing agents were set to ratios of 0.1, 0.67, 1.0, and 2.0 with respect to the Mn2+ mole concentration. KMnO4 exhibited a higher removal efficiency of Mn2+ than did H2O2 and NaOH, where approximately 90% of Mn2+ was removed by KMnO4. A black MnO2 was precipitated that indicated the oxidation of Mn2+ to Mn4+ after an oxidizing agent was added. In addition, MnO2 (pyrolusite) is a stable precipitate under pH-Eh conditions in the solution. However, relatively low removal ratios (6%) of Mn2+ were observed in the artificial mine drainage that included 1.0 mM of Fe2+. The rapid oxidation tendency of Fe2+ as compared to that of Mn2+ was determined to be the main reason for the low removal ratios of Mn2+. The oxidation of Fe2+ showed a decrease of Fe concentration in solution after injection of the oxidizing and neutralizing agents. In addition, Mn7+ of KMnO4 was reduced to Mn2+ by Fe2+ oxidation. Thus, the concentrations of Mn increased in artificial mine drainage. These results revealed that the oxidation method is more effective than the neutralization method for Mn removal in solution. It should also be mentioned that to achieve the Mn removal in mine drainage, Fe2+ removal must be conducted prior to Mn2+ oxidation.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.612-623
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• 2020

This study was initiated to quantitatively evaluate the inhibitory effects of five heavy metals (Cd, Cu, Zn, Pb, Ni) on bacterial growth and phosphorus removal in the binary culture of Alcaligenes sp. plus Pseudomonas sp. IC50 values of Alcaligenes sp. plus Pseudomonas sp. for Cd, Cu, Zn, Pb, and Ni were 0.75, 10.93, 7.08, 13.30, and 15.78 mg/L, respectively. For the binary treatments of heavy metals, IC50 was the lowest in the treatment of Cd + Cu, whereas, it was the highest in the Ni + Pb treatment. The EC50 values for Cd, Cu, Zn, Pb, and Ni were 0.54, 11.08, 6.14, 9.33, and 13.81 mg/L, respectively. For the binary treatments of heavy metals, EC50 was the lowest in the Cd + Zn, whereas, the highest in the Zn + Ni. Based on both IC50 and EC50 values for the binary culture of bacteria with the binary mixtures of heavy metals, the most interactive effect was found to be antagonistic, though the only synergistic effect was found in Cu + Ni treatment. Therefore, our results can provide basic data on the toxic effects of heavy metals on the bacterial growth and phosphorus removal in the wastewater treatment process.