• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.306-313
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• 2014

Super duplex stainless steels (sDSS) are excellent for use under severely corrosive conditions such as offshore and marine applications like pipelines and flanges. sDSS has better mechanical properties and corrosion resistance than the standard duplex stainless steel (DSS) but it is easier for a sigma phase to appear, which depresses the mechanical property and corrosion resistance, compared to DSS, because sDSS has a higher alloy element than DSS. In addition, sDSS has a feeble ductile-brittle transition temperature (DBTT) because it has a 50% ferrite microstructure. In the actual operating environment, sDSS would be thermally affected by welding and a sub-zero temperature environment. This study analyzed how precipitated sDSS behaves at a sub-zero temperature through annealing heat treatment and a sub-zero tensile test. Six types of specimens with annealing times of up to 60 min were tested in a sub-zero chamber. According to the experimental results, an increase in the annealing time reduced the elongation of sDSS, and a decrease in the tensile test temperature raises the flow stress and tensile stress. In particular, the elongation of specimens annealed for 15 min and 30 min was clearly lowered with a decrease in the tensile test temperature because of the increasing sigma phase fraction ratio.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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• pp.148-154
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• 2018

When shooting small arms, the inner surface temperature is heated up to about $700{\sim}1,000^{\circ}C$ by the friction of the bullet and the inner wall of the barrel and the combustion of propellant. High-temperature propellant gas and high-speed movement of the bullet cause corrosion of the inner wall, which is noticeable immediately in front of the chamber. In this study, the mechanical properties of Cr-Mo-V steel, which is the base material, were tested using Taguchi experimental design to find the best nitriding treatment conditions. For the nitriding process, the working time, salt bath temperature, and salt concentration were combined as three conditions and placed in the $L_9(3^4)$, orthogonal array table. The thicknesses of the white layer and the nitrogen diffusion layer were measured after nitriding under each condition in a salt bath furnace. Durability was evaluated by measuring the degree of dispersion through actual shooting because it was difficult to evaluate the mechanical properties of the cylinder inner structure. As a result, it was confirmed that the durability was optimal at $565^{\circ}C$, 1 hour, 0.5%. These optimal conditions were selected by the statistical analysis of the Minitab program(ver.17).

• The Korean Journal of Emergency Medical Services
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• v.9 no.1
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• pp.33-41
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• 2005

In Korea, the number of those who were drowned of the dead by 'accident and injury' ranked the third of causes of death is over 2,300 people a year. So the Ministry of Home Affairs arranged '119 drowning rescue team' at frequent occurrence regions of drowning temporarily as a part of drowning rescue measures during every summer season and made perfection more perfect for safety control and rescue services at prevention areas of accidents. However, considering that the number of professional drowning rescuers is small and it is managed temporarily only for summer, the placement of special rescue team equipped with professional education and qualification should be ensured and quick lifesaving and first-aid treatment should be conducted, since much time is required to arrive at accident place after receiving accident report at 119 office, rapid rescue and relief have not been achieved. Therefore, the placement of special rescue team should be increased for reducing the personal damages by considering regional characteristics and in particular placement of more drowning rescue teams in Jeonnam region which has more seas and rivers is needed This study aims at analyzing relief activities and statistics to cope with water accidents and achieve qualitative growth of first-aid services, examining actual conditions of water accident relief team and personnel assignment, providing first-aid services of good quality and establishing improvement methods to increase operation of relief team.

• Journal of Korean society of Dental Hygiene
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• v.7 no.3
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• pp.273-284
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• 2007

Oral health in youth is very important because this period influences life for adult remarkably. Therefore, more effective oral health education and recognition of early treatment for oral disease are required sincerely. For more effectual education for high-school students, it is necessary to consider their circumstance like obesity and smoking. This study will analyze the correlation oral health behavior with obesity and subjective oral health concerns. In addition to, the actual condition of smoking for high-school girls and oral health condition will be verified. A survey was progressed for high-school girls in Busan city and BMI(body mass index) was used for classification of weight. The statistical significance was analyzed using SPSS 13.3 for Windows. Results of this study is following. 1. The frequence of daily toothbrushing was significantly different with obesity although difference of oral health knowledge was not significant. The frequency of toothbrushing of overweight students were lesser than the others. This results may be caused by low-level for oral health concerns and by passive life style of fat person. This habit has possibility of causing serious periodontal disease like periodontitis and tooth caries. 2. The correlation of obesity and time of brush change, using for supplement, and recent dental institution was insignificant. However, concerns of oral health were showed significantly according to obesity. Under-weight and standard-weight students were more concerned about oral health than over-weight. This results can be related to frequence of toothbrushing for fat subject. This relevance of two factors was confirmed by logistic regression analysis. 3. Approximately 70% students have smoking experience responded to uncomfortableness of periodontal conditions. On the other hand, non-smoking students felt uncomfortable in 50%. This results indicated that smoking have an effect on oral health condition. Further study which identify periodontal conditions practically has to go on for verification of direct correlation smoking and oral health.

• Environmental Engineering Research
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• v.18 no.4
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• pp.229-234
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• 2013

This study aimed to develop a new dust collecting system equipped with an activated carbon (A.C.) coated electrode. Before fabrication, pre-treatment of A.C. was performed to remove metal ions within the A.C. to enlarge its specific surface area. Then, pre-treated A.C., black carbon, polyvinyl acetate (PVAc), and methanol were mixed to make a gel compound, which was coated onto aluminum plates to fabricate electrodes. The optimal mixing ratio of A.C., black carbon, PVAc, and methanol was found to be 10 g: 2 g: 3 g: 20 mL. After fabrication, the electrodes were used in the batch-type experiment for $NH_3$ and $H_2S$ removal. The reduction rates of the gases were high at the beginning and slowly reduced with time. Dust collection experiments were conducted in continuous flow, with various voltages applied. Compared to 5 kV, dust removal efficiency was 1.5 times higher when 10 kV was applied. Increasing the number of electrodes applied also increased the collecting efficiency. The correlation coefficient between actual collecting efficiency and trend line was higher than 99%. Consequently, the novel dust collection system equipped with A.C. coated electrode appears to be a promising substitute for existing dust-control devices.

• The Korean Journal of Emergency Medical Services
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• v.11 no.2
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• pp.87-101
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• 2007

Health and disease related characteristics of 226 selected by systematic sampling from 452 personal emergency response system(PERS) beneficiaries and actual conditions of using PERS by them are as follows. Over 86% of PERS beneficiaries have not good health conditions and 70.7% of them have chronic diseases. On social supports family was highest as 52.2% and cases having social workers' assistance were 15.2%, but 53 as 23.7% had not visit or call from anyone and showed very low social supports. 86.2% was given PERS within 3years and 79.1% had it by the recommendation from related agencies and 4.0% was by their demand. On wearing it, 78.3% didn't bring it with them and 92% of them answered they were not sick and then it was found that they didn't use it because they had not special emergency. On satisfaction with paging system's operation, 81.3% answered they were satisfied with it, 48.8% used it for 'acute and emergency diseases' and 29.3% called ambulance for 'appointed medical treatment'. Time required for ambulance to arrive at the field was within 10 min. in 87.8% and after 10 min. in 12.2% and emergency service for beneficiaries by fire service was very good. On satisfaction with use of PERS, 85.4% were satisfied with it, 81.9% who requested repair or replacement of radio paging got it back after one or two days of their request and they answered they were satisfied with A/S. 45.5% answered they powered off it because 'they didn't use it' and 12.1% had 'economical reason of phone charge'.

• Journal of Korean society of Dental Hygiene
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• v.8 no.1
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• pp.1-12
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• 2008

I investigated the situation of self-realization for oral malodor and real occurrence of it and researched the situation of coincidence by self-administrated questionnaire and real oral malodor of dental hygiene students in Kyeonggi province and Kyeongbuk province to use as a reference data on prevention and treatment of oral malodor. The obtained results were as follows: 1. Concerning the grade of the subjective symptom of oral odor, a little bit oral malodor was the highest by reaching 77.6%, and no oral malodor was 20%. 2. The time when one feels the oral malodor highest was revealed immediately after awakening from the sleep by running up to 88.2%. 3. Concerning the extent of aversion during the occurrence of oral malodor from other people, 57.6% expressed as unpleasant, and 3.5% showed no aversion. 4. Concerning the intention to participate in the prevention program against the oral malodor, 51.8% had intention of it. 5. Hydrogen sulfide 7.61V19.30, methyl mercaptan 9.53V67.90, dimethyl sulfide 58.31V121.37(pF0.05) marked as causing factors in the 132 respondents who answered that they had a little bit oral malodor in comparison with the grade of subjective symptom and the measurement of actual oral malodor. As the above-mentioned results were obtained by limited subjects, the more diversified and precise comparative study is considered to be needed through the classification of various levels of research subjects.

• Journal of Gastric Cancer
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• v.19 no.2
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• pp.165-172
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• 2019

Purpose: The robotic system for surgery was introduced to gastric cancer surgery in the early 2000s to overcome the shortcomings of laparoscopic surgery. The more recently introduced da Vinci $Xi^{(R)}$ system offers benefits allowing four-quadrant access, greater range of motion, and easier docking through an overhead boom rotation with laser targeting. We aimed to identify whether the $Xi^{(R)}$ system provides actual advantages over the $Si^{(R)}$ system in gastrectomy for gastric cancer by comparing the operative outcomes. Materials and Methods: We retrospectively reviewed all patients who underwent robotic gastrectomy as treatment for gastric cancer from March 2016 to March 2017. Patients' demographic data, perioperative information, and operative and pathological outcomes were collected and analyzed. Results: A total of 109 patients were included in the $Xi^{(R)}$ group and 179 in the $Si^{(R)}$ group. Demographic characteristics were similar in both groups. The mean operative time was 229.9 minutes in the $Xi^{(R)}$ group and 223.7 minutes in the $Si^{(R)}$ group. The mean estimated blood loss was 72.7 mL in the $Xi^{(R)}$ group and 62.1 mL in the $Si^{(R)}$ group. No patient in the $Xi^{(R)}$ group was converted to open or laparoscopy, while 3 patients in the $Si^{(R)}$ group were converted, 2 to open surgery and 1 to laparoscopy, this difference was not statistically significant. Bowel function was resumed 3 days after surgery, while soft diet was initiated 4 days after surgery. Conclusions: We found no difference in surgical outcomes after robotic gastrectomy for gastric cancer between the da Vinci $Xi^{(R)}$ and da Vinci $Si^{(R)}$ procedures.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.4
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• pp.77-89
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• 2024

Knee osteoarthritis (OA) is a very common musculoskeletal disorder worldwide. The assessment of knee osteoarthritis, which requires a rapid and accurate initial diagnosis, is determined to be different depending on the currently dispersed classification system, and each classification system has different criteria. Also, because the medical staff directly sees and reads the X-ray pictures, it depends on the subjective opinion of the medical staff, and it takes time to establish an accurate diagnosis and a clear treatment plan. Therefore, in this study, we designed the stenosis length measurement algorithm and Osteophyte detection and length measurement algorithm, which are the criteria for determining the knee osteoarthritis grade, separately using CNN, which is a deep learning technique. In addition, we would like to create a grading system that integrates and complements the existing classification system and show results that match the judgments of actual medical staff. Based on publicly available OAI (Osteoarthritis Initiative) data, a total of 9,786 knee osteoarthritis data were used in this study, eventually achieving an Accuracy of 69.8% and an F1 score of 76.65%.

• Journal of Korean Neurosurgical Society
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• v.67 no.5
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• pp.493-509
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• 2024

In neurointensive care units (NICUs), particularly in cases involving traumatic brain injury (TBI), swift and accurate decision-making is critical because of rapidly changing patient conditions and the risk of secondary brain injury. The use of artificial intelligence (AI) in NICU can enhance clinical decision support and provide valuable assistance in these complex scenarios. This article aims to provide a comprehensive review of the current status and future prospects of AI utilization in the NICU, along with the challenges that must be overcome to realize this. Presently, the primary application of AI in NICU is outcome prediction through the analysis of preadmission and high-resolution data during admission. Recent applications include augmented neuromonitoring via signal quality control and real-time event prediction. In addition, AI can integrate data gathered from various measures and support minimally invasive neuromonitoring to increase patient safety. However, despite the recent surge in AI adoption within the NICU, the majority of AI applications have been limited to simple classification tasks, thus leaving the true potential of AI largely untapped. Emerging AI technologies, such as generalist medical AI and digital twins, harbor immense potential for enhancing advanced neurocritical care through broader AI applications. If challenges such as acquiring high-quality data and ethical issues are overcome, these new AI technologies can be clinically utilized in the actual NICU environment. Emphasizing the need for continuous research and development to maximize the potential of AI in the NICU, we anticipate that this will further enhance the efficiency and accuracy of TBI treatment within the NICU.