• Journal of the Korean earth science society
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• v.26 no.1
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• pp.30-40
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• 2005

The purpose of this study is to analyze gifted students' perception of the teaching activities at the gifted science high school (Busan Science Academy), in Busan, Korea, and to investigate the science experiment class practice. In this study, a questionnaire about the curriculum courses, teaching strategies, and evaluation method of the school was administered to 139 gifted students. The verbal interactions during the science experiment class were audio and videotaped, transcribed, and analyzed. The results of this study are as follows: First, according to the gifted students' perception, the credits of specialized courses and advanced elective courses need to be increased and the credits of general courses need to be reduced. Second, teachers at this school mainly use teaching strategies such as lecture, group activities, and discussion; on the other hand, the students prefer diverse teaching strategies such as discussion, lecture, experiment, inquiring activities, and problem solving. Third, students prefer a writing test assessment rather than a written report assessment or portfolio assessment. Fourth, the patterns of verbal interaction were different depending on the level of the teachers' questions and interactions between the students in the experiment class facilitated students' inquiry.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.3
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• pp.186-195
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• 2018

Purpose: We performed quantitative and qualitative analysis of typical periodontal bacteria using real time PCR method to investigate the microbiological difference according to the severity of peri-implant disease in Koreans. Materials and Methods: Total of 60 implants were divided into three groups (healthy group, peri-implant mucositis group, peri-implantitis group) through periapical radiographs and clinical indices. The evaluated clinical parameters were pocket depth, plaque index, suppuration and bleeding on probing. Using a sterilized curette instrument, microbial samples were collected from the subgingival plaque and real-time PCR was performed on five periodontal bacteria. The relative expression levels of microorganisms were compared by comparative delta-CT method. Results: The relative expression levels of E. corrodens and T. denticola were significantly higher in the peri-implantitis group (P < 0.017). On the other hand, the relative expression level of F. nucleatum and P. gingivalis was relatively high in the healthy implant group regardless of the severity of disease. P. intermedia was significantly lower in the healthy implant group (P < 0.017). Conclusion: Periodontal bacteria were detected in Koreans with peri-implant diseases, but there was no microbiological distribution similar to periodontitis.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.4
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• pp.19-33
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• 2008

Dynamic response measurements from natural excitation were carried out for 25- and 42-story buildings to evaluate their inherent properties, such as natural frequencies, mode shapes and damping ratios. Both are reinforced concrete buildings adopting a core wall, or with shear walls as the major lateral force resisting system, but frames are added in the plan or elevation. In particular, shear walls in a 25-story building are converted to frames from the 4th floor level downwards while maintaining a core wall throughout, resulting in a fairly complex structure. Due to this, along with similar stiffness characteristics in the principal directions, significantly coupled and closely spaced modes of motion are expected in this building, making identification rather difficult. By using various state-of-the-art system identification methods, the modal parameters are extracted, and the results are then compared. Three frequency-domain and four time-domain based operational modal identification methods are considered. Overall, all natural frequencies and damping ratios estimated from the different identification methods showed a greater consistency for both buildings, while mode shapes exhibited some degree of discrepancy, varying from method to method. On the other hand, in comparison with analysis results obtained using the initial finite element(FE) models, test results exhibited a significant difference of about doubled frequencies, at least for the three lower modes in both buildings. To improve the correlation between test and analysis, a few manual schemes of FE model updating based on plausible reasons have been applied, and acceptable results are obtained. The advantages and disadvantages of each identification method used are addressed, and some difficulties that might arise from the updating of FE models, including automatic procedures, for such large structures are carefully discussed.

• Composites Research
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• v.29 no.2
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• pp.73-78
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• 2016

In this paper, The concept of a wheel with carbon fiber composite is to replace the conventional material used for a wheel hub, such as plastic, with a disk-type hub made of carbon fabric and epoxy resin. The impact load from the ground under real conditions was considered; a low-velocity impact test was conducted to evaluate the impact performance of the carbon wheel and compare it with that of a conventional plastic wheel. This study applied a 70 J impact load as a test condition. The impact energy was controlled in the test by adjustment of height and weight of impactor. The use of a carbon disk wheel hub was confirmed to reduce weight and generate an excellent repulsive force at low energy under conditions similar to real driving conditions. The results showed that the maximum load increased proportionally depending on the impact load, but the growth of the maximum load was reduced at a 20 J impact load and tended to decrease at a 45 J impact load. The carbon wheel showed excellent properties ; the level of rebounding was 35.3% and 19.1% of the total impact energy at impact loads of 5 J and 10 J, respectively. On the other hand, the carbon disk wheel rebounded less than 5% of the total energy due to crack generation of the thin carbon hub for impact loads of more than 20 J.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.10
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• pp.979-984
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• 2015

In the present paper, we evaluate the effects of the safe-end length and thickness of the similar metal weld (SMW) of safety injection nozzles on stress distributions at the dissimilar metal weld (DMW). For this evaluation, we carry out detailed 2-D axisymmetric finite element analyses by considering four different values of the safe-end length and four different values of the thickness of SMW. Based on the results obtained, we found that the SMW thickness affects the axial stresses at the center of the DMW for the shorter safe-end length; on the other hand, it does not affect the hoop stresses. In terms of the safe-end length, the values of the axial and hoop stresses at the inner surface of the DMW center increase as the safe-end length increases. In particular, for the cases considered in the present study, the stress distributions at the DMW center can be categorized according to certain values of safe-end length.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7021-7027
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• 2014

Background: The problem of cancer, especially lung cancer, is very acute in Bangladesh. The present study was conducted to evaluate the risk of lung cancer among Bangladeshi people based on hereditary, socio-economic and demographic factors. Materials and Methods: This study was carried out in 208 people (patients-104, controls-104) from January 2012 to September 2013 using a structured questionnaire containing details of lung cancer risk factors including smoking, secondhand smoke, tobacco leaf intake, age, gender, family history, chronic lung diseases, radiotherapy in the chest area, diet, obesity, physical activity, alcohol consumption, occupation, education, and income. Descriptive statistics and testing of hypotheses were used for the analysis using SPSS software (version 20). Results: According to this study, lung cancer was more prevalent in males than females. Smoking was the highest risk factor (OR=9.707; RR=3.924; sensitivity=0.8872 and P<0.0001) followed by previous lung disease (asthma, tuberculosis etc.) (OR=7.095; RR=1.508; sensitivity=0.316 and P<0.0001)) for male patients. Highly cooked food (OR=2.485; RR=1.126; sensitivity=0.418 and P=0.004)) and also genetic inheritance (OR=1.93; RR=1.335; sensitivity=0.163 and P=0.138) demonstrated significant correlation with lung cancer as risk factors after these two and alcohol consumption was not prevalent. On the other hand, for female patients, tobacco leaf intake represented the highest risk (OR=2.00; RR=1.429; sensitivity= 0.667 and P=0.5603) while genetic inheritance and highly cooked food also correlate with lung cancer but not so significantly. Socioeconomic status and education level also play important roles in causing lung cancer. Some 78.5% male and 83.3% of female cancer patients were rural residents, while 58.2% lived at the margin or below the poverty line. Most male (39.8%) and female (50.0%) patients had completed only primary level education, and 27.6% male and 33.3% female patients were illiterate. Smoking was found to be more prevalent among the less educated persons. Conclusions: The results obtained in this study indicate the importance of creating awareness about lung cancer risk factors among Bangladeshi people and making appropriate access to health services for the illiterate, poor, rural people.

• Journal of dental hygiene science
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• v.17 no.4
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• pp.306-314
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• 2017

The purpose of this study was to examine the validity of the content of an educational curriculum by understanding the opinions of experts in the development of weekly educational content for dental communication or communication-related subjects. It was composed of educational content on how to communicate with patients by cultivating a professional attitude through basic contents and a self-understanding of communication. Three experts were asked to evaluate the feasibility of educational contents and their appropriateness in order to evaluate the criteria for certification as a dental hygienist. The validity of the weekly educational contents and the period of education were awarded 4 points out of a maximum of 5 points; overall, the curriculum was evaluated to be valid and to be acceptable for use as criteria for certification evaluation. On the other hand, it was confirmed that not only should the contents be made appropriate for the grade level, but it should be complemented so that theoretical and practical learning can be achieved in a gradual and interrelated manner rather than as a one-time curriculum. Therefore, the result of this study can be considered for use as background data for curriculum development, and for standardization of the communication course in the dental hygiene department.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.1
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• pp.109-115
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• 2014

This paper investigated the optimal conditions for coffee extraction and dilution by comparing differences in soluble compounds and sensory characteristics of coffee subjected to cold-water extraction according to water quantity and dilution ratio. For sample preparation, we extracted coffee for 3 to 10 hours by adding 400 mL, 600 mL, 1,000 mL and 1,800 mL of cold water ($20^{\circ}C$) to 100 g of ground coffee, resulting in 200 mL, 400 mL, 800 mL and 1,600 mL portions of extracted coffee, respectively. Following this, the 200 mL, 400 mL and 800 mL portions of extracted coffee were further diluted with 1,400 mL, 1,200 mL and 800 mL of cold water, resulting in ratios of coffee to cold water of 1:7, 1:3 and 1:1, respectively. The 1,600 mL of portion of extracted coffee was not diluted and used as a sample. Undiluted coffee showed the highest values for pH, acidity, reducing sugar, total soluble solids and total phenolic compounds among all sample coffees, whereas the highly diluted coffee with a high ratio of 1:7 showed the lowest values. In a descriptive test, odor, sourness, bitterness and body intensity were also the highest in undiluted coffee due to the overly extracted coffee compounds. Undiluted coffee showed the lowest preference in terms of aroma, aftertaste and balanced coffee taste. On the other hand, diluted coffee at a ratio of 1:7 showed the lowest values for odor, sourness, bitterness and body intensity. Diluted coffee at a ratio of 1:3 showed the highest values for sweetness and acidity and was the most preferred in terms of aroma, aftertaste and balance. As a result, our study concluded that the optimal conditions for extraction and dilution of coffee with cold water are a ratio of ground coffee to cold water of 1:6 (w/v), followed by further dilution of the coffee by cold water at a ratio of 1:3.

• Archives of Reconstructive Microsurgery
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• v.7 no.2
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• pp.135-145
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• 1998

In 1980 Morrison and O'Brien reported their experiences about the reconstruction of amputated thumb using wrap-around neurovascular free flap from the great toe with a nonvascularized iliac bone graft. From then it has been considered to be a good reconstructive procedure for the amputated thumb, but it's indication has been limited distal to the metacarpophalangeal(MP) joint. We have performed 37 cases of wrap-around free flap from the great toe for the reconstruction of thumb amputated at distal or proximal to the MP joint and investigated their functional results according to the level of amputation. Level of amputation was distal to the MP joint in 25 cases and proximal to it in 12 cases. Pinching and grasping power, two point discrimination and the amount of opposition to the other fingers were compared to the uninjured hand. Pinching and grasping power were not significantly different according to the level of amputation but the amount of two point discrimination was significantly high in the cases amputated proximal to the MP joint. The opposition of reconstructed thumb to the other fingers was completely possible in all cases amputated distal to the MP joint. In 12 cases amputated proximal to the MP joint of the thumb, opposition was completely possible in 6 cases in which the iliac bone block was fixated in the position of $30^{\circ}$ flexion and $45^{\circ}$ internal rotation but in 6 cases in the fixation of $30^{\circ}$ flexion and $30^{\circ}$ internal rotation, the opposition of reconstructed thumb to the ring and little fingers were impossible in 5 cases and only to the little finger in 1 case. In this study, we concluded that even if amputation proximal to the MP joint, it is no more contraindication of the wrap-around free flap procedure for thumb reconstruction, however in these cases we recommend iliac bone block fixation in the position of $30^{\circ}$ flexion and $45^{\circ}$ infernal rotation for the better functional outcome.

• The Journal of Engineering Geology
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• v.26 no.3
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• pp.371-382
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• 2016

Saltwater intrusion in coastal regions can be detected by using numerous geochemical constituents in groundwater. However, insufficient numbers of groundwater data can often make us difficult to interpret saltwater intrusion. Probability statistics technique enables statistical prediction using a limited numbers of water quality data for a wider range and can make to effectively evaluate saltwater intrusion through a characterized distribution of probability. This study evaluated saltwater intrusion by applying probability statistics to the chemical constituents in groundwater, coastal discharge, and stream water in the coastal areas of Busan City. By the result of the study, it is proven that Na⁺, Mg²⁺, K⁺, SO₄²⁻, and Cl⁻, abundantly contained in seawater, are valuable indicators for evaluating saltwater intrusion. On the other hand, it is judged that Si⁴⁺, Fe²⁺, NO₃⁻, and PO₄³⁻, showing similar probability distribution in groundwater, coastal discharge, and stream water, are not appropriate indicators for the detection of saltwater intrusion.