• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.3
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• pp.137-149
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• 2021

Cable-stayed bridges are infrastructure facilities of a highly public nature; therefore, it is essential to ensure operational safety and prompt response in the event of a collapse or damage caused by natural and social disasters. Among social disasters, impact accidents can occur in bridges when a vehicle collides with a pier or when crashes occur due to aircraft defects. In the case of offshore bridges, ship collisions will occur at the bottom of the pylon. In this research, a procedure to evaluate the structural behavior of a cable-stayed bridge for aircraft impact is suggested based on a numerical analysis approach, and the feasibility of the procedure is demonstrated by performing an example assessment. The suggested procedure includes 1) setting up suitable aircraft impact hazard scenarios, 2) structural modeling considering the complex behavior mechanisms of cable-stayed bridges, and 3) structural behavior evaluation of cable-stayed bridges using numerical impact simulation. It was observed that the scenario set in this study did not significantly affect the target bridge. However, if impact analysis is performed through various scenarios in the future, the load position and critical load level to cause serious damage to the bridge could be identified. The scenario-based assessment process employed in this study is expected to facilitate the evaluation of bridge structures under aircraft impact in both existing bridges and future designs.

• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.10-19
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• 2024

The purpose of this study is to conduct a summative evaluation of the usability of a general-purpose ventilator to determine whether it can be used for its intended purpose in the intended environment by the intended user and to find possible errors in use. The importance of ventilators has increased due to the accelerated aging of the population and the impact of the pandemic. In addition, patients who require ventilators are often in critical condition, so even a small error in use can be fatal. Therefore, it is important to ensure that the ventilator has sufficient stability and can be used satisfactorily without inconvenience to the user. In this study, we conducted a usability test with 17 respiratory nurses with more than 3 years of experience using the ventilator. We analyzed the task success rate, satisfaction, and opinions of the intended users while going through a total of 17 scenarios. Satisfaction was captured through an ASQ questionnaire and subjective opinions were captured through a detailed opinion questionnaire. The results showed a high level of satisfaction with an average score of 6.3 for the use scenarios. Evaluators expressed satisfaction with the overall visibility and versatility of the features, but noted that improvements were needed for calibration tasks with low task success rates. As the calibration method is different from other equipment, it was suggested that specific explanations of the calibration method and the picture that appears when calibrating are needed, and that if relevant training is provided, the equipment can be used without problems. If the usability evaluation is not limited to securing efficiency and satisfaction from the intended users, but also continuously receives feedback from users to prepare for use in emergency environments such as pandemic situations, it will be very helpful to seize opportunities such as emergency authorization in future situations, and ultimately contribute to patient safety by reducing use errors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1520-1527
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• 2013

The purpose of this study is to derive COE reduction targets of offshore wind power in Korea. In addition, innovation factors for achieving the COE reduction targets were derived. Also the COE reduction targets of offshore wind power was to improve that national policy, technology, industry and improving regulations would like to help. The results of this study has been created based on the various assumptions, scenarios and experts' discussions. Currently, offshore wind power generation price is 229.72won/kWh in 2012. According to the study, COE of offshore wind power has been proposed 88.8won/kWh at third scenario by 2030. This result has shown competitiveness with fossil fuel power generation.

• Journal of Korean Academy of Nursing
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• v.38 no.1
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• pp.83-91
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• 2008

Purpose: The purpose of this study was to test the validity of a modified clinical performance examination (CPX) for preclinical students in nursing. Method: 70 nursing students in their second semester of the junior year at C University participated in CPX. Scenarios and checklists were developed by our research team from September to October 2005. Six stations were organized. Evaluation included physical examination of a patient with lung cancer, education on usage of a metered dosage inhaler, and lobectomy postoperative care. Students were randomly assigned to a station. Result: There was a difference in the CPX scores according to stations. The agreement of scoring between trained faculty members and SPs was more than moderate (r=.647). The correlation between the CPX score and the average grade in the previous semester and between the CPX score and the average grade of a paper and pen test of the pulmonary system of adults was low (r=.276; r=.048). Conclusion: Traditional CPX is generally recommended, however, modified CPX is appropriate for preclinical students in the current Korean Nursing school setting if there are additional scoring systems to balance the testing level at each station.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.6
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• pp.298-306
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• 2002

We performed an safety evaluation on constructing of a common grounding system for electrical railway in view of its efficacy and technical fit. In order to compare the conventional grounding method, which has been individually conducted, with the common grounding with all ground wires connected in common to the counterpoise buried below the surface of the earth in parallel with rail, we set up scenarios with several cases of fault and load conditions in Chungbuk railway sections with the common grounding system. Based on models for railway conductors including the grounded system, line Parameters of railway power system are computed. The circuit model for power system with up and down lines, auto-transformers and railway substations is used to compute impedances of counterpoise and substation ground net. For each scenario with faults and operation conditions of railway, the induced potentials on signal and communication lines are also computed. It is shown that the common grounding for Chungbuk railway is superior experimentally to the conventional method in three respects: (1) the lower rail potentials during operation of railway in line, (2) the lower rail potentials for short-circuit faults between catenary and rail, and (3) the lower stress voltages on signal and communication lines for short-circuit or ground faults. The analysis results confirm that the grounding system for electric railway is required to be built by the common grounding and be evaluated on its safety in design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.214-220
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• 2008

This study aims to design a digital portfolio assessment system in ubiquitous computing(DPASUbi). To achieve that goal, the following issues were worked: Review of various theoretical discussions on portfolio and an analysis of existing programs to select elements to be included in the DPASUbi. Educational evaluation scenarios for the DPASUbi were developed based on the elements. The system was designed on reflecting these elements, that is, learning activities, assessment and usage of portfolio, ubiquitous technology and database. This system will provide guidance on what methods and assessment procedures should be applied in the ubiquitous computing environment totally different from the conventional one. Also, The new system will be helpful in indicating what kind of techniques should be required in the real educational evaluation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.18-27
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• 2007

Successful operation of power system under regulated as well as deregulated electricity markets is very important. This paper presents marginal power flow evaluation of KEPCO system in view point of physical and operation mode by using Physical and Operational Margins (POM Ver.2.2), which is developed by V&R Energy System Research. This paper introduces feature and operation mode of POM Ver.2.2 and then evaluates scenarios of 6 lines contingencies of 765kv of KEPCO system at peak load time on summer in 2006 you. The case study for actual 2006 year KEPCO system shows that this POM program is applicable sufficiently to KEPCO system. Futhermore, it demonstrates that it is helpful for operator's operating the system successfully by evaluating physical and operational margins quickly for various contingencies occurred in KEPCO system. Eventually, it will assist operators to operate more reliably the KEPCO system in future.

• Earthquakes and Structures
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• v.12 no.6
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• pp.653-663
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• 2017

A seismic margin assessment evaluates how much margin exists for the system under beyond design basis earthquake events. Specifically, the seismic margin for the entire system is evaluated by utilizing a systems analysis based on the sub-system and component seismic fragility data. Each seismic fragility curve is obtained by using empirical, experimental, and/or numerical simulation data. The systems analysis is generally performed by employing a fault tree analysis. However, the current practice has clear limitations in that it cannot deal with the uncertainties of basic components and accommodate the newly observed data. Therefore, in this paper, we present a Bayesian-based seismic margin assessment that is conducted using seismic fragility data and fault tree analysis including Bayesian inference. This proposed approach is first applied to the pooltype nuclear research reactor system for the quantitative evaluation of the seismic margin. The results show that the applied approach can allow updating by considering the newly available data/information at any level of the fault tree, and can identify critical scenarios modified due to new information. Also, given the seismic hazard information, this approach is further extended to the real-time risk evaluation. Thus, the proposed approach can finally be expected to solve the fundamental restrictions of the current method.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.370-379
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• 2011

The increasing complexity of complex buildings, such as high-rise buildings and underground subway stations, presents new challenges to firefighters. In a fire in complex buildings, the importance of the collaboration between firefighters is clear. The increased demand on firefighter training for such environment is now evident. Due to cost, time, and safety issues, it is impossible to experience a real fire in such environments for training. In addition, the use of real fire for training does not enable repeatable training and the evaluation of the training is difficult. We developed a team-based firefighter training simulator for complex buildings using the virtual reality technology. It provides the training and evaluation of firefighting and mission-based team training. To model real fire phenomena in virtual space, a numerical analysis method based on fire dynamics is used. To achieve an immersive virtual environment, an augmented reality technique for the compensation of real world image and a haptic technique for heat experience are adopted. The developed training simulator can help the firefighter to respond to large and complex firefighting scenarios, while maintaining the safety of the trainees.

• Korean Journal of Adult Nursing
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• v.20 no.4
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• pp.548-560
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• 2008

Purpose: This study was conducted to develop a simulation-based education course and to evaluate the results after the application for second year nursing students. Methods: This study was a non-equivalent control pre-post design. Based on the clinical situation scenarios about patients with COPD and MI, a total of two simulation-based learning modules was developed. Pretest and posttest was conducted to evaluate the difference in critical thinking disposition, problem solving, and clinical competence between two groups of 102 students for the experimental group, 2007 and 90 students for the control group, 2006. The experimental group conducted a clinical performance evaluation in the final test, on December 10, 2007. Results: In the experimental group, knowledge related to learning objectives was significantly increased and core intervention was performed almost exactly, but the same result was not observed in domains of analysis of laboratory test, and nursing education for patients. Self-evaluated clinical competence and problem solving level were significantly more improved in the experimental group than control group, but critical thinking disposition level wasn't. Conclusion: In conclusion, a simulation-based education course needs to utilize self-directed learning module like computer-based learning through web contents and MicroSim and video productions for improving nursing students' critical thinking.