• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.1
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• pp.143-143
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• 1996

Recent Class requirements and IMO recommendations concerning Hull Strength Monitoring (HSM) have prompted an increasing number of shipowner to adopt monitoring systems on bulk carriers and tanker. Such systems are designed to give warning when stress levels and the frequency and magnitude of ship motions approach levels which require corrective action. When fitted these systems provide enhanced operational safety and efficiency. This paper describes a development beyond the standard BMT HSM system through the integration of stress, motion and radar-based sea state monitoring with powerful, on-board, artificial intelligence (AI) tools. The latter utilises conceptual clustering techniques as an aid to pattern recognition in stress, fatigue. motion and sea state data clusters. This, in turn, provides additional operational guidance for ship's staff. Feedback from applications of the standard BMT HSM and extended HSM systems on board the British Steel Bulk Shipping fleet is described.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.1
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• pp.67-72
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• 2019

Myasthenia gravis (MG) is a neuromuscular autoimmune disorder which clinically presents as muscular weakness and fatigue due to autoantibody formation against acetylcholine receptors (AChR), leading to their subsequent destruction. Due to the neuromuscular implications of MG, certain considerations must be taken into account when providing anesthesia to MG patients. In the following case report, we have outlined procedural considerations for the anesthetic management of a patient with MG undergoing deep sedation for an elective oral surgery in an outpatient setting, as well as a discussion of relevant literature.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.193-202
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• 2011

Purpose: The aim of this study was to evaluate the effect of pre-treatment of core and hydrothermal treatment on the bond strength and flexural strength of ceramic veneered zirconia. Methods: 3Y-TZP specimens(KaVo Zr, $25mm{\times}3mm{\times}1mm$)were prepared by five pre-treatment methods and divided into seven groups including control two groups, subsequently the specimens veneered with the E-MAX ceram according to manufacturer's information(total specimen thickness 1.5mm). Two groups from ceramic-zirconia specimens(n=105, n=15 per group)were assigned into two experimental fatigue conditions, namely storage in an autoclave at $134^{\circ}C$ for 5h, thermo-cycling(3,000cycles, between 5 and $55^{\circ}C$, dwell time 45s, transfer time 2s). A flexural strength test was performed in a universal testing machine(crosshead speed: 0.5mm/min). Data were statistically analyzed using one-way ANOVA and Tukey's test(${\alpha}$=0.05). Results: The ceramic-zirconia bond strength value for liner application group(LLW, $27.3{\pm}3.8$) were significantly lower than those of the pre-treatment groups($30.72{\pm}5.3$). The ceramic-zirconia bond strength and zirconia flexural strength was not affected by thermo-cycling(p>0.05), whereas it was affected by storage in an autoclave at $134^{\circ}C$ for 5h(p<0.05). Conclusion: The results indicated that the ceramic-zirconia bond strength and zirconia flexural strength was affected by low temperature degradation.

• 한국노년학
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• v.30 no.1
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• pp.21-30
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• 2010

Obese people experience dissatisfaction of body, depression, anxiety, and emotional disturbance by social prejudice and discrimination, further they represent decline of health-related quality of life. Exercise therapy is recommended as one of the positive treatments to improve the emotional pain of obese people. This study is to provide guideline of exercise prescription for obese people by investigating the effects of qigong exercise on psychological factors such as health-related quality of life (SF-36), self-efficiency, depression, anxiety, and fatigue in obese people. The subjects of this study were 50~60s adults participated in Golden-Wellbeing program at S university in G gu of S city and were devided into exercise (N=17) and control (N=16) group. Qigong exercise was performed twice per week for 12 weeks and SF-36, self-efficiency, depression, anxiety, and fatigue were measured before and after 12 weeks of exercise. In the 8 items of SF-36 before and after 12 weeks of qi-gong exercise, there was no significance in role limitation-emotional (F=0.187, p=0.668), mental health (F=2.043, p=0.163) between groups, but there was significance in physical functioning (F=15.151, p<0.001), role limitation-physical (F=18.278, p<0.001), social functioning (F=4.957, p=0.033), vitality (F=11.485, p=0.002), bodily pain (F=6.623, p=0.015), and general health (F=4.498, p=0.042) between groups. Also, anxiety (F=0.631, p=0.433) was not significant, whereas self-efficiency (F=6.124, p=0.019), depression (F=5.109, p=0.031), fatigue (F=7.998, p=0.008) was significant between groups. Even though qigong is slow motion and low intensity of exercise, it was found that qi-gong has exercise effect which induces mental and psychological improvement through this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.36-41
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• 2014

Electro-Mechanical Actuator installed on aircraft consists of a decelerator which magnifies the torque to rotate an axis connected with aircraft control surface, a control section which controls the motor assembly through receiving orders from cockpit and a motor assembly which rotates the decelerator. EMA controls aircraft attitued, position, landing, takeoff, etc. It is important part of a aircraft. Aircraft maneuvering make vibration of EMA. Vibration may cause the vibration fatigue. For that reason, it is necessary to analyze the system safety. In this paper, first EMA is modeled in finite element method and analyzed the response from input vibration. second EMA is tested and analyzed from modal experimental data. third EMA Fe model is updated and re analyzed. and EMA is verified safety with $3{\sigma}$ stress and S/N curves.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.167-175
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• 2014

If volumetric flaws such as bearing pad fretting flaws and debris fretting flaws are detected in the pressure tubes of pressurized heavy water reactors during in-service inspection, the initiation of fatigue cracks and delayed hydrogen cracking from the detected volumetric flaws shall be assessed by using elastic stress concentration factors in accordance with CSA N285.8-05. The CSA N285.8-05 presents only an approximate formula based on linear elastic fracture mechanics for the debris fretting flaw. In this study, an engineering formula considering the geometric characteristics of the debris fretting flaw in detail was derived using two-dimensional finite element analysis and Kinectrics, Inc.'s engineering procedure with slight modifications. Comparing the application results obtained using the derived formula with the three-dimensional finite element analysis results, it is found that the results obtained using the derived formula agree well with the results of the finite element analysis.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.393-399
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• 2018

It is well recognized that residual stresses of the rails, generated from the manufacturing process including roller straightening and heat treatment, play an important role in determining fatigue and fracture properties of the rails. Thus, it has been a challenge to measure the residual stresses accurately. In this work, contour method was employed to evaluate the residual stresses existing in interior of the rails. The cross section perpendicular to the longitudinal direction of the rail was cut at a very slow rate using electric discharge machining (EDM), after which a laser-based flexural measuring instrument enabled us to precisely measure the flection of the cross section. The measured data were converted into the residual stresses using the commercial finite element package, ABAQUS, through a user-defined element (UEL) subroutine, and the residual stresses of the new rails (50N, KR60, UIC60) with three different specifications were compared.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.377-384
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• 2022

Vortex-induced vibration (VIV) occurs owing to the vortex generated from the back side of the appendages of ships and submarines during operation. Recently, the importance of high-order modes (HOMs) vibration and fatigue failure has become increasingly emphasized by increasing the speed of ships and the size of structures. In addition, predicting the vibration of HOMs is significantly necessary as the VIV becomes stronger in the fast flow speed condition than in the low flow speed condition. This study introduces a methodology according to HOMs hybrid Fluid Structure Interaction (FSI) for predicting the HOMs VIV on the hydrofoils. The HOMs FSI system is verified by comparing the VIV results from the FSI simulation with the experimental results. Finally, the effectiveness of the HOMs FSI is determined by applying the maximum von-Mises stress obtained from the VIV on the hydrofoil to the S-N curve released from Det Norske Veritas (DNV). VIV results from the HOMs FSI include the lock-in characteristics as well as a significant increase of more than 10 times compared with that of low-order modes (LOMs) FSI. In the future works, advanced studies will be required for improving cantilever boundary conditions and the shape of hydrofoils.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.369-377
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• 2003

The aim of this study was to evaluate the effect of two polishing methods and chemical conditioning on the surface of hybrid composites. Ninety cylindrical specimens (diameter：8mm, depth：2mm) were made with three hybrid composites-Filtek Z250, Tetric Ceram. DenFil. Specimens for each composite were randomly divided into three treatment subgroups $^{\circled1}$ Mylar strip (no treatment). $^{\circled2}$ Sof-Lex XT system, $^{\circled3}$ PoGo system. Average surface roughness(Ra) was taken using a surface profilometer at the time of setting and after immersion into 0.02N lactic acid for 1 week and 1 month. Representative specimens were examined by scanning electron microscopy. The data were analyzed using ANOVA and Scheffe's tests at 0.05% significance level. The results were as follows：1. Mylar strip resulted in smoother surface than PoGo and Sof-Lex system (p<0.001). Sof-Lex system gave the worst results. 2. Tetric Ceram was smoother than DenFil and Z250 when cured under only mylar strip. However, it was significantly rougher than other materials when polished with PoGo system. 3. All materials showed rough surface after storage in 0.02N lactic acid, except groups polished with a PoGo system. The PoGo system gave a superior polish than Sof-Lex system for the three composites. However. the correlation to clinical practice may be limited, since there are several processes. such as abrasive, fatigue, and corrosive mechanisms. Thus. further studies are needed for polishing technique under in vivo conditions.

• Korean Journal of Acupuncture
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• v.40 no.2
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• pp.44-53
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• 2023

Objectives : This study was conducted to reveal the relationship between multiple factors of traditional Korean Medicine diagnosis and consider the further probabilities of treating people with physical and mental problems not defined as diseases, which is called 'Mibyeong' in traditional Korean Medicine. Methods : 40 healthy participants were included in the observational clinical trial. The participants were asked to complete health questionnaires (e.g. State-Trait Anxiety Inventory, Pittsburgh Sleep Quality Index, Stress Response Inventory) and they went through a traditional diagnosis process, including four stages of diagnosis (looking, listening/smelling, inquiring, and pulse taking), by a Korean Medicine doctor. Both the Korean Medicine doctor and an artery tonometry device performed the pulse diagnosis. Results : Although all participants were healthy people with no history of disease, more than half of participants had a problem related with severe level of fatigue (n=19), sleep disturbance (n=26) and stress (n=27) status according to the related questionnaires. Participants diagnosed with phlegm syndrome by the Korean Medicine doctor showed significantly greater score in phlegm pattern questionnaires than participants who were not. However, there was little agreement between the doctor's pulse diagnosis and radial artery tonometry results. Conclusions : We conducted a pulse diagnosis and measured health-related information along with the traditional Korean Medicine diagnose procedure, including four stages of diagnosis, and we found a linkage between diagnosis of phlegm and the phlegm pattern questionnaire score. The results suggest that a number of healthy participants, with no disease diagnosed, have Mibyoung symptoms which need further clinical management. Thus, we suggest that Mibyoung management programs based on qualified diagnosis tools and traditional Korean medicine diagnosis procedures be developed, and that future research using various diagnostic tools be carried out on a large population.