• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.843-850
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• 2020

The purpose of this study is to evaluate the structural risk and weakness of a railway tank car through nonlinear collision analysis according to overseas collision safety standards. The goal is to propose a crash safety design guideline for railway tank cars for transporting dangerous goods in Korea. We analyzed the buffer impact test procedure of railway freight cars prescribed in EN 12663-2 and the tank puncture test criteria prescribed in 49CFR179. A nonlinear finite element model according to each standard was modeled using LS-DYNA, a commercial finite element analysis solver. As a result of the buffing impact test simulation, it was predicted that plastic deformation would not occur at a collision speed of 6 km/h or less. However, plastic deformation was detected at the rear of the center sill and at the tank center supporting the structure at a collision speed of 8 km/h or more. As a result of a head-on test simulation of tank puncture, the outer tank shell was destroyed at the corner of the tank head when 4% of the kinetic energy of the impacter was absorbed. The tank shell was destroyed in the area of contact with the impacter in the test mode analysis of tank shell puncture when the kinetic energy of the moving vehicle was reduced by 30%. Therefore, the simulation results of the puncture test show that fracture at the tank shell and leakage of the internal material is expected. Consequently, protection and structural design reinforcement are required on railway tank cars in Korea.

• International Journal of Quality Innovation
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• v.9 no.3
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• pp.1-14
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• 2008

Patient satisfaction with the Emergency Department(ED) in a hospital is related to the length of stay, and especially to the amount of waiting time for medical treatments. ED overcrowding decreases quality and efficiency, therefore affecting hospitals' profitability. This paper presents a forecasting and simulation model for resource management of the ED at Moses H. Cone Memorial Hospital. A linear regression forecasting model is proposed to predict the number of ED patient arrivals, and then a simulation model is provided to estimate the length of stay of ED patients, system throughput, and the utilization of resources such as triage nurses, patient beds, registered nurses, and medical doctors. The near future load level of each resource is presented using the proposed models.

• Communications for Statistical Applications and Methods
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• v.27 no.1
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• pp.97-108
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• 2020

This paper compares several methods for estimating parameters of normal inverse Gaussian distribution. Ordinary maximum likelihood estimation and the method of moment estimation often do not work properly due to restrictions on parameters. We examine the performance of adjusted estimation methods along with the ordinary maximum likelihood estimation and the method of moment estimation by simulation and real data application. We also see the effect of the initial value in estimation methods. The simulation results show that the ordinary maximum likelihood estimator is significantly affected by the initial value; in addition, the adjusted estimators have smaller root mean square error than ordinary estimators as well as less impact on the initial value. With real datasets, we obtain similar results to what we see in simulation studies. Based on the results of simulation and real data application, we suggest using adjusted maximum likelihood estimates with adjusted method of moment estimates as initial values to estimate the parameters of normal inverse Gaussian distribution.

• Journal of Korea Foundry Society
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• v.18 no.6
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• pp.578-585
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• 1998

A multi-purpose code MAGMA was employed for mold design and process control in producing Al wheel by lowpressure die casting. Three-dimensional solid modeling was followed by mesh generation of casting and molds(top, bottom and side). The simulation of stability of casting cycle time, mold filling simulation with pressure variation from P1 to P2, solidification simulation by solidification time and feeding criteria, and temperature distribution of molds during processes were studied in this research. The thermal stability of molds was attained after 5 cycles when molds were preheated at $400^{\circ}C$. The pressure increase from P1 to P2 for mold filling was evaluated as slightly higher, and 6 seconds were taken for the mold filling. The cycle time was believed to be designed properly judged from the solidification time of casting and open/close time of molds.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.53-61
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• 2002

This paper aims to apply a supply chain modeling and its analysis framework to the supply chain in the port industry, each of which has its own objective. The simulation approach serves two purposes: to model a supply chain network in quantity approach and to evaluate its supply chain performance based on proposed strategies. The simulation model will be applied to quantifying the flow of a supply chain, the involved information and material flow and conducted to simulate the supply chain operations. The model will also be used which strategic and operational policies are the most effective in smoothing the variations in the supply chain.

• Journal of Internet of Things and Convergence
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• v.1 no.1
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• pp.33-38
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• 2015

Hardware are developed in various architecture. It is necessary to verifying value of variables in modules generated in each clock cycles for timing simulation. In this paper, a test vector generator in software type generates test vectors for timing simulation of 224-bit ECDSA hardware modules in developing stage. It provides test vectors with GUI format and text file format.

• Korean Journal of Adult Nursing
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• v.26 no.1
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• pp.1-10
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• 2014

Purpose: This study was conducted to test the impact of simulation-based education program for emergency airway management on self-efficacy and clinical performance ability. Methods: A quasi-experimental non-equivalent control group pre-post test design was used. A total of 60 nurses, 30 nurses assigned to the simulation-based education group and 30 nurses to a traditional lecture group. The treatment group received a lecture, small group workshop and team simulation whereas the comparison group received lectures. Results: The participants in the simulation-based education group reported significantly higher self-efficacy of emergency airway management compared to participants in the lecture only group (t=5.985, p<.001). The simulation-based education group showed significantly higher clinical performance ability of emergency airway management compared with the lecture group (t=5.532, p<.001). Conclusion: Simulation-based education was verified to be an effective teaching method to improve the self-efficacy, clinical performance skills of nurses in the learning of emergency airway management.

• The Journal of Korean Academic Society of Nursing Education
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• v.17 no.2
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• pp.226-234
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• 2011

Purpose: The purpose of this study was to identify the effect of a simulation-based practice on clinical performance and problem solving processes for nursing students. Method: The study used a one group pre-post test design. Students experienced a simulation-based practice that included team base learning, skill training, taking a high-fidelity simulation with SimMan 3G, and also being debriefed for 12 weeks (August 2010 to December 2010). The pre-test and post-test were conducted to compare the differences in knowledge, clinical nursing skills, and problem solving processes. Result: After students had received the simulation-based practice, they showed statistically significant higher knowledge (t=14.73, p<.001) and clinical nursing skills (t=15.47, p<.001) than before. However, there was no significant difference in the problem solving process score (t=1.53, p=.127). Conclusion: This study showed that knowledge and clinical nursing skills were significantly improved by the simulation-based practice. Further research would be required to identify how the problem solving process that uses simulation-based practice could be developed further.

• The Journal of Korean Academic Society of Nursing Education
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• v.17 no.2
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• pp.246-256
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• 2011

Purpose: With the decrease in available clinical sites, a decrease in adequately prepared clinical faculty, and demand to prepare health care students to begin work, we need alternative methods to teach clinical skills for health care professionals. The use of simulation as an educational process that can replicate clinical practices is becoming popular in nursing. Therefore, this study was conducted to review directions of simulation-based learning in nursing education. Methods: A systematic review of quantitative studies was undertaken using Medline, KERIS, and KISS. The primary search terms were simulation and nursing. Reference lists from relevant papers and the websites of relevant nursing organizations were also searched. Nine studies met inclusion criteria and were analyzed in detail. Results: All studies reported simulation as a valid teaching/learning strategy. Six of the studies (66.7%) showed that simulation technology was a practical and successful model to use in teaching a variety of clinical skills for nursing students and nurses. Conclusion: Simulation may have some advantages over other teaching methods, depending on the scenario, context, topic, and method. Further study is needed to determine the effect of team size on learning and to develop a universal method of outcome measurement.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.2
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• pp.176-187
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• 2002

This paper focuses on the study of simulation and evolution of Micro Air Vehicles. Micro Air Vehicles or MAVs are small flying robots that are used for surveillance, search and rescue, and other missions. The simulated robots are designed based on realistic characteristics and the brains (controllers) of the robots are generated using genetic algorithms, i .e., simulated evolution. The objective for the experiments is to investigate the effects of robot team size and topology (simulation environment) on the evolution of simulated robots. The testing of team sizes deals with finding an ideal number of robots to be deployed for a given mission. The goal of the topology experiments is to see if there is an ideal topology (environment) to evolve the robots in order to increase their utility in most environments. We compare the results of the various experiments by evaluating the fitness values of the robots i .e., performance measure. In addition, evolved robot teams are tested in different situation in order to determine if the results can be generalized, and statistical analysis is performed to evaluate the evolved results.