• Steel and Composite Structures
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• v.35 no.4
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• pp.599-609
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• 2020

The tension-only braced frames (TOBFs) are widely used as a lateral force resisting system (LFRS) in low-rise steel buildings due to their simplicity and economic advantage. However, the system has poor seismic energy dissipation capacity and pinched hysteresis behavior caused by early buckling of slender bracing members. The main concern in utilizing the TOBF system is the determination of appropriate performance factors for seismic design. A formalized approach to quantify the seismic performance factor (SPF) based on determining an acceptable margin of safety against collapse is introduced by FEMA P695. The methodology is applied in this paper to assess the SPFs of the TOBF systems. For this purpose, a trial value of the R factor was first employed to design and model a set of TOBF archetype structures. Afterwards, the level of safety against collapse provided by the assumed R factor was investigated by using the non-linear analysis procedure of FEMA P695 comprising incremental dynamic analysis (IDA) under a set of prescribed ground motions. It was found that the R factor of 3.0 is appropriate for safe design of TOBFs. Also, the system overstrength factor (Ω₀) was estimated as 2.0 by performing non-linear static analyses.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.573-580
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• 2013

The combined effects of reactivity coefficients, along with other core nuclear characteristics, determine reactor core behavior in normal operation and accident conditions. The Power Coefficient of Reactivity (PCR) is an aggregate indicator representing the change in reactor core reactivity per unit change in reactor power. It is an integral quantity which captures the contributions of the fuel temperature, coolant void, and coolant temperature reactivity feedbacks. All nuclear reactor designs provide a balance between their inherent nuclear characteristics and the engineered reactivity control features, to ensure that changes in reactivity under all operating conditions are maintained within a safe range. The $CANDU^{(R)}$ reactor design takes advantage of its inherent nuclear characteristics, namely a small magnitude of reactivity coefficients, minimal excess reactivity, and very long prompt neutron lifetime, to mitigate the demand on the engineered systems for controlling reactivity and responding to accidents. In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity. It will be demonstrated that during Loss of Regulation Control (LORC) and Large Break Loss of Coolant Accident (LBLOCA) events, the impact of variations in power coefficient, including a hypothesized larger than estimated PCR, has no safety-significance for CANDU reactor design. Since the CANDU 6 PCR is small, variations in the range of values for PCR on the performance or safety of the reactor are not significant.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.1
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• pp.94-101
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• 2018

With the development of industrial technology and science, production and manufacturing facilities have been enhanced and improved, and the importance of the safety of workers has also been regulated and limited by various safety management methods. As a way to secure the safety of the workers from the production facility, the fail-safe and fool-proof methods are now being applied. Any possible insecure behavior and unsafe conditions can be removed by adopting the standards and specifications that are now secure the safety of workers and equipment. This research analyzes EN ISO 13849-1 international and European standards during CE certification. In order to secure acceptable reduced risks, the risk assessment process of ISO 12100 and the processes for reducing its risk are applied. In the current ISO 13849-1 standard, the criteria for the required performance level PLr (Required Performance Level) for the applicable risk and safety functions through the risk assessment are subjective and not subdivided. Therefore, the evaluation criteria are likely to cause judge's judgement error due to qualitative judgement. This research focuses on evaluation and acceptable performance level setting for the safety circuit of the equipment. We propose an objective and specific evaluation criteria to secure safety, and the proposed evaluation criteria are applied to the case study of the safety circuit for the equipment. In order to secure the safety of the entire safety circuit, the improvement of the MTTFd and DC level related to the SRP/CS (Safety-Related Parts of Control Systems)' lifetime is required for the future research.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.100-105
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• 2014

To design a submerged floating railway that is safe against underwater explosions, railway behavior must be investigated and clarified. In this paper, shock waves and impulse pressures generated by a charge away from the submerged floating railway are expressed using experimental formulas. The submerged floating railway tethered by mooring lines is modeled as a simply supported beam with elastic springs. Finite element analysis for the beam model subjected to impulse loading is conducted so that the response of the submerged floating railway can be investigated. For design purposes, a simplified analysis method combined with dynamic load factor is proposed for the same model. Maximum deformation and internal forces are calculated and compared with the time dependent analysis results. It is shown that the simplified analysis results show good agreement.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.287-297
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• 2017

This exploratory study aimed to explore the perception (knowledge and attitude) and behaviors of medical personnel regarding medical device safety and to identify the differences in results linked with the type of their task. A questionnaire was administered to medical personnel working at a tertiary care hospital with 900 beds in Incheon, Korea, and 220 completed questionnaires were used for analysis. The results revealed that the majority of the medical personnel perceived the potential risk involved in different types of medical devices they use and stated that they need training programs for safe use of medical devices. Concerning the perception regarding medical devices across different positions within the hospital, it was found that the residents had a low awareness about safety issues, although the medical services they handled involve high risks, thereby calling for safety training. Further nationwide studies are needed to improve the quality and validity of data and eventually to provide important information required by policy makers and academicians to manage medical device safety.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.4 s.74
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• pp.369-374
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• 2006

This paper describes dynamic characteristics of a power transmission tower consisting of lots of power lines and insulators. A numerical 3D modeling for the static, dynamic and buckling analyses of the power transmission tower is presented considering the case when the power lines are cut. Eigenvalue analysis indicates that the transmission tower shows different behavior comparing to usual structures governed by several low modes. The transmission tower is governed by lots of modes. It is verified that the transmission tower is structurally safe against the static wind and buckling loads. But the structural and buckling safety is not guaranteed when all power lines are cut, which comes to collapse the transmission tower. Further study is in need to overcome such case. Wind dynamic analysis shows that fluctuating wind loads increase the response of the tower.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.223-231
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• 2020

Older drivers have an increased risk of accidents due to poor function, but they also develop self-regulation ability to check their own changes. Thus, information on whether the actual elderly driver responds to changes in driving ability and risk may provide a meaningful basis for the clinic and research of the elderly's driving ability assessment. Therefore, the purpose of this study is to provide basic data for the evaluation of elderly drivers by analyzing the driving risk self-perception characteristics in terms of driving behavior and function with Korean elderly drivers. A self-reporting assessment was conducted on 500 elderly drivers living in the community and the characteristics of driving risk perception were analyzed. As a result, it was confirmed that many elderly drivers are aware of the driving risk when their vision and hearing are impaired or when they find it difficult to adapt to changes in driving conditions. On the other hand, the characteristics of insensitive reactions to changes in medical health conditions, such as drug use or epilepsy, seizures, and loss of consciousness, were identified. The researcher hopes this study will contribute to the safety management of elderly drivers in Korea, where aging is accelerating.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.17-27
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• 2004

A new earthquake design method performing iterative calculations using secant stiffness was developed. The proposed design method has the advantages of convenience and stability in numerical analysis because it uses elastic analysis. At the same time, the proposed design method can accurately estimate the strength and ductility demands on the members because it performs the analysis on the inelastic behavior of structure using iterative calculation. In the present study, the procedure of the proposed design method was established, and a computer program incorporating the proposed method was developed. Design examples using the proposed method were presented, and its advantages were presented by the comparisons with existing design methods using elastic or inelastic analysis. The proposed design method, as an integrated method of analysis and design, can address the earthquake design strategy devised by the engineer. such as ductility limit on each member, the design concept of strong column - weak beam, and etc. In addition, through iterative calculations on the structure preliminarily designed only with member sizing, the strength and ductility demands of each member can be directly calculated so as to satisfy the given design strategy. As the result. economical and safe design can be achieved.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.173-183
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• 2004

The purpose of the present study was to assess food hygiene and safety knowledge, attitudes, and practices of food-service personnel in school food-service programs and to find factors affecting their knowledge, attitudes, and practices. A self-administered questionnaire was offered to a random sample of 40 kitchen employees in elementary schools in one region of Korea, with 37 completing the survey, a response rate of 92.5%. The survey was carried out over a two-month period (April-May, 2001). Knowledge score of the employees was high with a mean/standard deviation of 4.75/0.32 on a 5.0-point scale. They had significantly lower attitude score (4.55$\pm$0.33) and practice score (4.55$\pm$0.45) compared to the score of knowledge (p＜0.05). Logistic regression analysis showed that (1) the employees＇ education level and work experience in school food-service programs affected their knowledge, (2) age, level of living, monthly income, and housing type affected their attitudes, and (3) monthly income, level of living, housing type, and work experience in school food-service programs affected their practices. Pearson＇s correlation analysis confirmed that the knowledge and attitude scores were significantly correlated (r=0.598, p＜0.001). The results indicate that the knowledge, attitude, and practice levels of the employees regarding the food hygiene and safety were better than expected, however, the results suggest a need for the adoption of approaches which take account of socio-economic and environmental influences on behavior to improve and maintain their practice level. The food-handling practices of school food-service employees need to be monitored routinely in order to ensure that safe food is served to our school children.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.823-829
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• 1997

The patients visiting pediatric dental office have been being younger than the previous, and they were often combined with systemic disease. But, we aren't able to perform the verbal communication, because of their impediment and youthfullness. And, we can't carry out the behavior control via physical restraint, as the developed social structure and the attitude of children and their parents. So, the importance and concerning of conscious sedation using sedative medicine are increased by time and time. Among the various conscious sedation, Chloral Hydrate and Nitrous Oxide inhalation are most popularly used, and barbiturates, benzodiazepine, opioids and hydroxyzine are used often. But, these medications have some side-effects and adverse reactions, may be failed to sedate the children. And limited use of medically compromised patients, especially for ASA class III, IV or more dangerous patients. We, the Department of Pediatric Dentistry, Chosun University have met some dangerous situation due to unfavorable pharmacogenic reactions, but we can control the situation and get well healed results. The below results are common situations and their solutions during conscious sedation. 1. By the intravenous administration, thrombophlebitis is the most common side-effects, but it may be healed with time without any special treatment. 2. Under the definitive guidelines about conscious-sedation, we can perform a safe conscious sedation for ASA class III patients. 3. When adversed reaction of Benzodiazepine is occured, it could be cared effectively with benzodiazepine antagonist, named Flumazenil.