• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.127-134
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• 2022

Among many contributing factors of implant failure, excessive loading and inflammation contribute mainly to increasing implant failure rate. Especially, poor oral hygiene around implants is one of the most common reasons for implant failure. When implant prosthesis fails to function, the clinician should re-diagnose and plan treatment using the remaining implants. Additional implantation may be needed to make a new type of prosthesis or either implant-assisted RPD and implant overdenture treatment may be performed using the remaining implants. In this article, a patient whose fixed implant prosthesis in the maxilla had failed of poor oral hygiene maintenance was reported to be recovered with removable implant overdenture by using remaining implant abutments and a milled bar with additional retentive elements. Through this treatment, the clinical results were satisfactory in terms of esthetics, masticatory function recovery and oral hygiene management.

• Archives of Plastic Surgery
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• v.50 no.3
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• pp.315-324
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• 2023

Hemoglobinopathies such as sickle cell disease (SCD) are traditionally considered a relative contraindication to free tissue transfer, due to concerns that erythrocyte sickling will increase the risk of microvascular thrombosis and flap failure. This article describes a case report with the successful use of free tissue transfer in a patient with SCD and provides a systematic literature review on free tissue transfer in SCD. A retrospective chart review was performed of a patient with SCD who underwent free tissue transfer at the authors' institution. A systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed using the keywords "free tissue transfer," "free flap," or "microsurgery" and "sickle cell" on PubMed, Ovid/Medline, and Scopus. A 29-year-old male with delayed presentation of an electrical burn to the face and scalp underwent wound closure with a free anterolateral thigh flap. Key management principles included red blood cell transfusion to keep hemoglobin S under 30% and hemoglobin greater than 10 g/dL, maintenance of hydration, normothermia, adequate analgesia, and postoperative anticoagulation. Systematic literature review identified 7 articles describing 13 cases of free tissue transfer in 10 patients with SCD, with combined complete free flap success in 10 of the 13 flaps. Free tissue transfer can be successfully performed in patients with SCD. However, evidence on the optimal management of this unique patient population in the perioperative period after free tissue transfer is limited to case reports in the literature.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.6
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• pp.1403-1412
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• 2019

Effect of damage and loss cost for downtime is huge, if physical devices such as turbines, pipe, and storage tanks are in the abnormal state originated from not only aging, but also cyber attacks on the control and monitoring system like PLC (Programmable Logic Controller). To improve availability and dependability of the physical devices, we design and implement an indirect health monitoring system which sense temperature, acceleration, current, etc. indirectly, and put sensor data into Influx DB in real-time. Then, the actual performance of detecting abnormal state is shown using the indirect health monitoring system. Analyzing data are acquired using the real-time indirect health monitoring system, abnormal state and security threats can be double-monitored and lower maintenance cost utilizing prognostics and health management.

• Journal of radiological science and technology
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• v.47 no.4
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• pp.287-294
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• 2024

Radiation oncology departments are at high risk for potential radiation safety incidents. This study aimed to identify risk factors for these incidents using the P-mSHEL (Patient, Management, Software, Hardware, Environment, and Liveware) model and to evaluate potential accident types through Failure Mode and Effects Analysis (FMEA). FMEA identified seven accident types with high Risk Priority Number (RPN). A total of 56 detailed risk factors were classified using the P-mSHEL model, and measures to prevent radiation safety incidents were implemented. The effect of these preventive measures on workers' safety perception was confirmed through two indicators (FMEA and safety perception). After implementing the preventive measures, the FMEA analysis showed that the highest reduction in RPN was for A-6 (radiation exposure while other patients/guardians are present) with a reduction rate of 33.3%, followed by B-3 (radiation exposure while staff are present) with a reduction rate of 33.3%. Overall safety perception significantly improved after the preventive measures (4.17±0.35) compared to before (2.76±0.33) (p<0.05), with notable increases in both employee safety culture (3.93±0.51) and patient safety culture (3.73±0.62) (p<0.05). This study identified risk factors in radiation oncology departments. Continuous management, maintenance, and fostering a strong safety culture are crucial for preventing incidents. Regular problem identification and collaboration with relevant departments are essential for maintaining safety standards.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.186-193
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• 2005

Purpose: To improve the management of a medical linear accelerator, the records of operational failures of a Varian CL2l00C over a ten year period were retrospectively analyzed. Materials and Methods: The failures were classified according to the involved functional subunits, with each class rated Into one of three levels depending on the operational conditions. The relationships between the failure rate and working ratio and between the failure rate and outside temperature were investigated. In addition, the average life time of the main part and the operating efficiency over the last 4 years were analyzed. Results: Among the recorded failures (total 587 failures), the most frequent failure was observed in the parts related with the collimation system, including the monitor chamber, which accounted for $20\%$ of all failures. With regard to the operational conditions, 2nd level of failures, which temporally interrupted treatments, were the most frequent. Third level of failures, which interrupted treatment for more than several hours, were mostly caused by the accelerating subunit. The number of failures was increased with number of treatments and operating time. The average life-times of the Klystron and Thyratron became shorter as the working ratio increased, and were 42 and $83\%$ of the expected values, respectively. The operating efficiency was maintained at $95\%$ or higher, but this value slightly decreased. There was no significant correlation between the number of failures and the outside temperature. Conclusion: The maintenance of detailed equipment problems and failures records over a long period of time can provide good knowledge of equipment function as well as the capability of predicting future failure. Wore rigorous equipment maintenance Is required for old medical linear accelerators for the advanced avoidance of serious failure and to improve the qualify of patient treatment.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.379-382
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• 2003

Construction concrete needs to maintain suitable environment which contains temperature and humidity etc. Then concrete shows own strength. The environment is not regular and contains many variables. Especially the climate element occupies many parts of variables. We have the climate environment which goes down to $-4^{\circ}C$. The factor that obstruct to construction is the failure at a construction progress. But it must be processed to be scheduled. Therefore we have to do the special care for factor of climate that obstruct to construction. We must make assurance doubly sure at the quality of concrete. We need maintenance of temperature and humidity for the hardening until the requirement period after a concrete pured in. We must do the care of curing sufficiently not to take the influence of injurious activity. This causes strength of concrete. Specific method of curing is according to each situation which is environment element. We wish to analyze curing course in construction of concrete at the paper. Also we wish to predict the problem as to consider curing and suggest the improvement plan through the paper.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.334-346
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• 2022

There is a lack of knowledge and information on the understanding and application of the Process Safety Management (PSM) system, recognized as a major cause of industrial accidents in small-and medium-sized workplaces. Hence, it is necessary to prepare a protocol to secure the practical and continuous levels of implementation for PSM and eliminate human errors through tracking management. However, insufficient research has been conducted on this. Therefore, this study investigated and analyzed the various violations in the administrative measures, based on the regulations announced by the Ministry of Employment and Labor, in approximately 200 small-and medium-sized PSM workplaces with fewer than 300 employees across in korea. This study intended to contribute to the prevention of major industrial accidents by developing a facility maintenance web program that removed human errors in small-and medium-sized workplaces. The major results are summarized as follows. First, It accessed the web via a QR code on a smart device to check the equipment's specification search function, cause of failure, and photos for the convenience of accessing the program, which made it possible to make requests for the it inspection and maintenance in real time. Second, it linked the identification of the targets to be changed, risk assessment, worker training, and pre-operation inspection with the program, which allowed the administrator to track all the procedures from start to finish. Third, it made it possible to predict the life of the equipment and verify its reliability based on the data accumulated through the registration of the pictures for improvements, repairs, time required, cost, etc. after the work was completed. It is suggested that these research results will be helpful in the practical and systematic operation of small-and medium-sized PSM workplaces. In addition, it can be utilized in a useful manner for the development and dissemination of a facility maintenance web program when establishing future smart factories in small-and medium-sized PSM workplaces under the direction of the government.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.1-8
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• 2023

If there is a defect in the wheel bearing, which is a major part of the car, it can cause problems such as traffic accidents. In order to solve this problem, big data is collected and monitoring is conducted to provide early information on the presence or absence of wheel bearing failure and type of failure through predictive diagnosis and management technology. System development is needed. In this paper, to implement such an intelligent wheel hub bearing maintenance system, we develop an embedded system equipped with sensors for monitoring reliability and soundness and algorithms for predictive diagnosis. The algorithm used acquires vibration signals from acceleration sensors installed in wheel bearings and can predict and diagnose failures through big data technology through signal processing techniques, fault frequency analysis, and health characteristic parameter definition. The implemented algorithm applies a stable signal extraction algorithm that can minimize vibration frequency components and maximize vibration components occurring in wheel bearings. In noise removal using a filter, an artificial intelligence-based soundness extraction algorithm is applied, and FFT is applied. The fault frequency was analyzed and the fault was diagnosed by extracting fault characteristic factors. The performance target of this system was over 12,800 ODR, and the target was met through test results.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.281-287
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• 2009

An eruption failure can be observed for child and adolescent periods when the primary dentition is changed to the permanent dentition through the mixed dentition frequently. The eruption failure can lead to miss erupting times of the tooth, then it will cause a lot of problems including root resorption, esthetic problem, transposition of adjacent tooth, malocclusoin and etc. Especially, the maxillary first molar is importantly concerned with occlusion and growth and is an essential tooth for development and maintenance of occlusion. So, it is a momentous part of more proper occlusal management to find these abnormal cases at the early stage and solve the problems. The sorts of eruption failures of the maxillary first molars can be divided into delayed eruption, impaction and the primary retention and the secondary retention. When physical obstacles cause impaction, first of all they must be removed then we can treat the impaction with observation after removal, surgical exposure or orthodontic traction. If the source of impaction is an ectopic eruption, the treatment can be a brasswire, a pendulum appliance, a space maintainer or space regainer after the extraction of the second deciduous tooth and etc. These cases are made a diagnosis of eruption failures of the maxillary first molars in mixed dentition period and have good prognosises after my treatments. So I reported them.

• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.1-9
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• 2019

Large-scale industrial boilers operating at high temperature and high pressure, have a large amount of water, and a large amount of energy is released at the time of explosion. Currently, most industrial boilers use gas fuel such as LNG and LPG, etc. and fuel exists in the same space as equipment, so there is a high possibility of secondary damage such as fire or explosion in the event of a boiler accident. Both special care and management are required to operate the very dangerous equipment that causes casualty 2.51 per accident. For boilers of a certain size or more, the Korea Energy Agency conducts inspections in accordance with the Energy Usage Rationalization Act, KS, and public notice of the Ministry of Industry, Trade and Resources. In this research, based on the results of the inspection, the hazard factorss are configured, and a questionnaire is conducted to the inspector, the equipment manager, the maintenance person, and the person in charge of the manufacturer. We analyzed the results by using AHP (Analytic Hierarchy Process). As a result of analysis, generally recognized hazard factorss are not good management, measurement failure, specification failure, water leak, leak analysis, but connection, welding, scale, and corrosion, etc. are relatively less important. It is judged that the adverse factors that are recognized to be highly important among all groups and careers are already well managed, but less important and adverse factors should be well managed to ensure that the safe usage of the boiler.