• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.33.1-33.10
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• 2022

Objectives: This study aimed to analyze the proximity of maxillary molar roots to their overlying cortical bone surfaces and the maxillary sinus. Materials and Methods: Cone-beam computed tomographic images of 151 patients with completely erupted upper molars that had 3 separate roots were studied. The following distances were measured: from the root apex to the cortical plate and maxillary sinus floor, and from the apical 3-mm level of the root to the cortical plate. Differences between groups were analyzed with 1-way analysis of variance and the Scheffé post hoc test, the significance of differences between cone-beam computed tomography views with the paired t-test, and the significance of differences among age groups with linear regression analysis. The significance level was set at p < 0.05. Results: The mesiobuccal and distobuccal root apexes of maxillary second molars were more distant from the buccal cortical plate than the maxillary first molars (p < 0.05). The apical 3-mm level of the mesiobuccal root of the first molar was closer to the buccal cortical bone than the second molar (p < 0.05). In the maxillary first molars, the thickness of the buccal cortical bone decreased in all roots with age (p < 0.05). In all root apexes of both molars, the difference in the vertical level between the maxillary sinus floor and the root apex increased with age (p < 0.05). Conclusions: Awareness of the anatomical profile of maxillary molar apices in relation to the cortical bones and maxillary sinus will be beneficial for apical surgery.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.186-197
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• 2023

In this study, we focus on the improvement of data quality transmitted from a weather buoy that guides a route of ships. The buoy has an Internet-of-Thing (IoT) including sensors to collect meteorological data and the buoy's status, and it also has a wireless communication device to send them to the central database in a ground control center and ships nearby. The time interval of data collected by the sensor is irregular, and fault data is often detected. Therefore, this study provides a framework to improve data quality using machine learning models. The normal data pattern is trained by machine learning models, and the trained models detect the fault data from the collected data set of the sensor and adjust them. For determining fault data, interquartile range (IQR) removes the value outside the outlier, and an NGBoost algorithm removes the data above the upper bound and below the lower bound. The removed data is interpolated using NGBoost or long-short term memory (LSTM) algorithm. The performance of the suggested process is evaluated by actual weather buoy data from Korea to improve the quality of 'AIR_TEMPERATURE' data by using other data from the same buoy. The performance of our proposed framework has been validated through computational experiments based on real-world data, confirming its suitability for practical applications in real-world scenarios.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.429-434
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• 2023

Kitchen cabinets are essential furniture for storing the kitchen tools, but their high installed location makes it difficult for users to access the upper of the cabinets. Therefore, in this paper, we propose a new type of kitchen cabinet that allows users to easily take out or store items by adding new height adjustment features while maintaining the function of the existing cabinet. For convenience and safety, an appropriate complex link mechanism is designed so that the selected floor, not the entire cabinet, can come down to a desired height with one operation. Moreover, the optimal descent path is set to prevent the floor tilting or interfloor interference during descent, and appropriate link shapes, lengths, and joint types are selected to implement it. FEA analysis is performed to ensure that the stretched complex linkage can support the load of the stored items and the feasibility of the height adjustable kitchen cabinet is verified through fabrication.

• Imaging Science in Dentistry
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• v.53 no.4
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• pp.303-312
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• 2023

Purpose: This study investigated the prevalence of developmental and acquired pathologic conditions associated with impacted third molars (3Ms) in a Southern Brazilian population and evaluated whether demographic and tooth characteristics were correlated with the presence of bone or tooth lesions. Materials and Methods: Panoramic radiographs were assessed for developmental (bone-related) or acquired (tooth-related) pathoses associated with impacted upper or lower 3Ms. Data on tooth positioning, tooth development, and patient demographics were collected. A trained, calibrated postgraduate student evaluated all images. Binary and multivariate logistic regression models were used to assess associations between outcomes and the demographic and radiographic variables. The threshold for statistical significance was set at 5% (P<0.05). Results: The sample comprised panoramic radiographs from 2054 patients, predominantly female (59.2%), with a mean age of 27.2±11.5 years. Overall, 4066 impacted 3Ms were evaluated, revealing 471 (11.6%) developmental and 710 (17.5%) acquired pathoses. Among the developmental pathoses, 460 (95.2%) were indicative of dentigerous cysts. Male sex, lower 3M location, vertical or distoangular positioning, and incomplete root formation were associated with an elevated likelihood of developmental pathology. Lower tooth position, complete root formation, and partial eruption were linked to an increased probability of an acquired pathology in the third or second molar. Conclusion: The prevalence of pathologic conditions associated with impacted 3Ms was low. Male sex, lower 3M placement, horizontal or distoangular positioning, and incomplete root formation were associated with developmental pathoses, while lower tooth position, complete root formation, and partial eruption were related to acquired pathoses.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.78-84
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• 2023

Recently, the world's countries are tightening regulations on CO2 and air pollutants emission to solve them. In addition, eco friendly vehicles is increasing to replace automobiles in internal combustion engine. The government is supporting the expansion of hydrogen refueling infrastructure according to the hydrogen economy road map. In particular, refueling station is important to secure the safety that supplies high-pressure hydrogen with a wide LFL range. This paper is on guidelines for the determination safety distances to ensure worker safety from accident as jet fire. The safety distance is set according to the procedure of the EIGA doc 075/21. For accident frequency is upper 3.5E-05 per annum, safety distance is decided via consequence analysis where the risk of harm is below individual harm exposure threshold.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.209-214
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• 2024

The purpose of this study is to analyze the spatial structure of laboring classes in Manchester in the 19th century. Manchester had districts where laboring classes lived in destitution. Elizabeth Gaskell's Mary Barton demonstrates the miserable state of laboring classes by depicting their small, dirty living residential spaces. Engels's The Condition of the Working Class in England analyzes the laboring classes in industrial areas in England, especially Manchester. The laboring classes' districts formed in a set pattern were separated from the area for bourgeois. It lied in the old district near commercial areas, while upper classes were outside areas. It was the dominant ideology that drove the transformation of Manchester as an industrial city characterized by separation.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.1
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• pp.40-48
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• 2023

Backgrounds/Aims: Timing of resection for synchronous colorectal liver metastasis (CRLM) has been debated for decades. The aim of the present study was to assess the feasibility of simultaneous resection of CRLM in terms of major complications and develop a prediction model for safe resections. Methods: A retrospective single-center study of synchronous, resectable CRLM, operated between 2013 and 2021 was conducted. Upper limit of 95% confidence interval (CI) of major complications (≥ grade IIIA) was set at 40% as the safety threshold. Logistic regression was used to determine predictors of morbidity. Prediction model was internally validated by bootstrap estimates, Harrell's C-index, and correlation of predicted and observed estimates. Results: Ninety-two patients were operated. Of them, 41.3% had rectal cancers. Major hepatectomy (≥ 4 segments) was performed for 25 patients (27.2%). Major complications occurred in 20 patients (21.7%, 95% CI: 13.8%-31.5%). Predictors of complications were the presence of comorbidities and major hepatectomy (area under the ROC curve: 0.692). Unacceptable level of morbidity (≥ 40%) was encountered in patients with comorbidities who underwent major hepatectomy. Conclusions: Simultaneous bowel and CRLM resection appear to be safe. However, caution should be exercised when combining major liver resections with bowel resection in patients with comorbid conditions.

• Journal of Digestive Cancer Research
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• v.11 no.2
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• pp.104-107
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• 2023

The Ministry of Health and Welfare of Korea has implemented various social security programs to ensure a basic standard of living and raise overall quality of life for all citizens. The Korean social security system provides social insurance, public assistance, and social welfare services. To achieve adequate drug benefits, the Drug Management Department of Health Insurance Review and Assessment Service (HIRA) implement drug management duties including drug listing, upper price limit setting, scope of benefits, and post-factum management. When a manufacturer or an importer wants to apply for National Health Insurance (NHI) coverage of the drug that has obtained safety and efficacy approval, the pharmaceutical benefit assessment committee of HIRA evaluates the drug's clinical efficacy and cost-effectiveness to determine whether or not to include the drug into the benefit package. The benefit standards for a listed drug (ingredient) are set either for the whole permitted range or a part of range with conditions. To increase the coverage rate for new drugs, the listed drugs are regularly reviewed for their value. The status of listed drugs can be adjusted or eliminated from the benefit package if the clinical efficacy turns out to be insignificant. Therefore, through these pharmaceutical management procedures, high-quality drugs are provided at reasonable prices, which save healthcare expenditure by price determination and selective coverage in consideration of economic evaluation.

• Journal of Korean Home Economics Education Association
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• v.20 no.2
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• pp.75-94
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• 2008

The purposes of this paper are to describe the newly established reference values of nutrient intakes: to apply the changed dietary reference intakes to the new text book based on the revised curriculum: and to contrive substantial contents in the domain of dietary life(foods & nutrition) of new text book. Dietary Reference Intakes for Koreans(KDRIs) is newly established reference values of nutrient intakes that are considered necessary to maintain the health of Koreans at the optimal state and to prevent chronic diseases and overnutrition. Unlike previously used Recommended Dietary Allowances for Koreas(KRDA), which presented a single reference value for intake of each nutrient, multiple values are set at levels for nutrients to reduce risk of chronic diseases and toxicity as well as prevention of nutrient deficiency. The new KDRIs include the Estimated Average Requirement(EAR), Recommended Intake(RI), Adequate Intake(AI), and Tolerable Upper Intake Level(UL). The EAR is the daily nutrient intake estimated to meet the requirement of the half of the apparently healthy individuals in a target group and thus is set at the median of the distribution of requirements. The RI is set at two standard deviations above the EAR. The AI is established for nutrients for which existing body of knowledge are inadequate to establish the EAR and RI. The UL is the highest level of daily nutrient intake which is not likely to cause adverse effects for the human health. Age and gender subgroups are established in consideration of physiological characteristics and developmental stages: infancy, toddler, childhood, adolescence, adulthood and old age. Pregnancy and lactation periods were considered separately and gender is divided after early childhood. Reference heights and weights are from the Korean Agency for Technology and Standards, Ministry of Commerce, Industry and Energy. The practical application of DRIs to the new books based on the revision in the 7th curriculum is to assess the dietary and nutrient intake as well as to plan a meal. It can be utilized to set an appropriate nutrient goal for the diet as usually eaten and to develop a plan that the individual will consume using a nutrient based food guidance system in the new books based on the revision in the 7th curriculum.

• Journal of radiological science and technology
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• v.38 no.3
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• pp.205-211
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• 2015

We evaluated the effectiveness of TL (Time Limit) method by comparing with NTL (Non-time limit) method when it is used for examinations for abdomen Anterior Posterior (AP) in this paper. The evaluation was conducted based on the comparison of dose, and of signal to noise ratio (SNR) and contrast to ratio (CNR) on both methods. The experiments were conducted with XGEO GC 80 (Samsung, Korea), Unfors ThinX RAD (Unfors, Sweden) and Rando Phantom (Alderson research laboratories, USA) and shielding material with the size of $5.5{\times}9{\times}0.1cm^3$. It was set to activate only two upper ionization chambers in automatic exposure control(AEC) mode and the tube-voltage was set to 80kVp. When the exposure time was limited, it is limited to 51 msec. The images both by NTL AEC method and TL AEC method were acquired when with and without attachment of shielding material on the upper ionization chambers. The images were evaluated by SNR and CNR which are the image evaluation methods using 'Image J'. The NTL AEC method showed increases in dose as much as 130.7% at maximum and 80% at minimum than other methods. The TL AEC method showed decreases in mAs and exposure dose than the NTL AEC method as much as 43.8% and 44.4% respectively. There were no significant differences in SNR or CNR for the experiments (($p{\geq}0.05$). Therefore, it is suggested that the TLAEC mode is more effective when examining patients who have high BMI index or a patient with a metallic substance in the body after surgery.