• Korean System Dynamics Review
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• v.16 no.3
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• pp.5-29
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• 2015

The importance of the concept of safety culture has increased in the security of high-risk facility after Chernobyl accident in 1986. This paper elaborated the concept of safety culture and its main factors by Causal Loop Diagram. Due to the decline of safety culture, the occurrence of incidents and accidents require more and more corrective actions to the members of high-risk facilities and thereby increasing their workloads. Employees who must complete the task within the given time have to have time pressures and don't comply with the rules and procedures. Also, a schedule pressure is a big stress for employees, causing mistakes in precision work. In order to improve these problems, CLD of the safety culture in this paper suggests hiring more workers, re-allocation of given workloads and strengthen the learning, communication capabilities and safety leadership. In addition, the two real accident cases were analyzed to test the feasibility of the System Dynamic simulation model through the process of structuring the fault trees on the stationary black out accident in Kori unit 1 in South Korea and Kleen Energy power station explosion in US. The simulation results show that the various safety factors cause the serious accident combined with mechanical failure and safety culture will reduce the possibility of the accidents in these high-risk organizations. This simulation model can contribute to analyzing the impact of the organizational and human factors of safety culture and can provide the alternatives in high-risk facilities.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.593-601
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• 2017

This study was attempted to provide nurse students with basic materials to improve their clinical practices, and to investigate changes in their views on Nursing Professionalism, Job satisfaction, and role conflicts. After experiencing clinical practices, their nursing professionalism(t=-2.184, p=.031) and job satisfaction (t=-2.068, p>.001) increased but role conflict (t=-3.729, p>.001) increased as well. They were satisfied with their jobs, building up nursing professionalism through clinical practices. However, they had also acquired time on thinking about their future jobs more deeply than before practices and realizing their roles in real sense. In particular, they felt stress in some of subcategories, personal inner conflicts (t=-3.729, p>.001), role obscurity (t=-5.720, p>.001) so it is necessary to review standards on their job and task in nurse education and clinical practices.

• Journal of the Ergonomics Society of Korea
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• v.30 no.5
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• pp.597-603
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• 2011

Objective: The objective of this study was to compare one-hand and two-hands lifting activity in terms of biomechanical stress for the range of lifting heights from 10cm above floor level to knuckle height. Background: Even though two-hands lifting activity of manual materials handling tasks are prevalent at the industrial site, many manual materials handling tasks which require the worker to perform one-hand lifting are also very common at the industrial site and forestry and farming. Method: Eight male subjects were asked to perform lifting tasks using both a one-handed as well as a two-handed lifting technique. Trunk muscle electromyographic activity was recorded while the subjects performed the lifting tasks. This information was used as input to an EMG-assisted free-dynamic biomechanical model that predicted spinal loading in three dimensions. Results: It was shown that for the left-hand lifting tasks, the values of moment, lateral shear force, A-P shear force, and compressive force were increased by the average 43%, as the workload was increased twice from 7.5kg to 15.0kg. For the right-hand lifting task, these were increased by the average 34%. For the two-hands lifting tasks, these were increased by the average 25%. The lateral shear forces at L5/S1 of one-hand lifting tasks, notwithstanding the half of the workload of two-hands lifting tasks, were very high in the 300~317% of the one of two-hands lifting tasks. The moments at L5/S1 of one-hand lifting tasks were 126~166% of the one of two-hands lifting tasks. Conclusion: It is concluded that the effect of workload for one-hand lifting is greater than two-hands lifting. It can also be concluded that asymmetrical effect of one-hand lifting is much greater than workload effect. Application: The results of this study can be used to provide guidelines of recommended safe weights for tasks involved in one-hand lifting activity.

• Culinary science and hospitality research
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• v.16 no.4
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• pp.206-219
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• 2010

The purpose of this study is to manage job stress of foodservice employees effectively by analyzing their job stressors and relationship of job satisfaction and turnover intention. It also analyzed the effects of social support and coping strategies on job stressors. The data for the study were collected through conducting a survey to the employees who work at hotel foodservice departments and buffet restaurants in Busan area. Major suggestions and significances of this study can be outlined as follows: First, it was found that 6 job related stressors(work environment, personal relation, role, task characteristics, career development, individual character). Second, it was revealed that personal relation and career development factors have an effect on employees' job satisfaction and turnover intention. Third, it was illustrated that social support and coping strategies have a moderating effect of job stressors between job satisfaction and turnover intention.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.848-853
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• 2004

Regarding to the project SUAV (Smart Unmanned Aerial Vehicle) in KARI (Korea Aerospace Research Institute), several engine configurations has been evaluated. However it's not an easy task to collect all the necessary data of each engine for the analysis. Usually, some kind of modeling technique is required in order to determine the unknown data. In the present paper a qualitative method for reverse engineering is proposed, in order to identify some design patterns and relationships between parameters. The method can be used to estimate several parameters that usually are not provided by the manufacturer. The method consists of modeling an existing engine and through a simulation, compare its transient behavior with its operating envelope. In the simulation several parameters such as thermodynamics, performance, safety and mechanics concerning to the definition of operation-envelope, have been discussed qualitatively. With the model, all engine parameters can be estimated with acceptable accuracy, making possible the study of dependencies among different parameters such as power-turbine total inertia, TIT, take-off time and part load, in order to check if the engine transient performance is within the design criteria. For more realistic approach and more detailed design requirements, it will be necessary to enhance the compressor map first, and more realistic estimated values must be taken into account for intake-loss, bleed-air and auxiliary power extraction. The relative importance of these “unknown” parameters must be evaluated using sensitivity analysis in the future evaluation. Moreover, fluid dynamics, thermal analysis and stress analysis necessary for the resulting life assessment of en engine, will not be addressed here but in a future paper. With the methodology presented in the paper was possible to infer the relationships between operation-envelope and engine parameters.

• Education of Primary School Mathematics
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• v.6 no.2
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• pp.75-84
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• 2002

After entering an elementary school, in fact, a number of children regard mathematics as one of very difficult subjects because of its abstractiveness. This is caused by the fact that their basic thinking power is not yet formed or they can not understand the special quality of mathematics. So this article emphasizes the need to build up the higher logical thought and a basic mathematical concept at the lower grade elementary school stage in which the loaming activity on mathematics begins in earnest, that is, at the stage before having an experience on the calculating activity using numbers. But at present the lower grade elementary school students in our country do not understand the special quality of mathematics composed of a various symbolic system and lay stress upon mathematics learning attached to the calculative activity. In order to make the right mathematical concept of the lower grade elementary school, the basic knowledge and ability as follows is sure to be formed. 1) the foundational logical manipulation activity and knowledge 2) the using ability of the sign and symbolic system At the stage on which mathematics learning activity begins, it is a very important task to make the right concept of the abstractive math and nurse the capability for finding mathematical relations covered under the sign system through the continuos loaming activity on . Through the basic logical manipulation activity and the game activity of sign for lower grade elementary school students mentioned in this article, they can not only foster the higher level logical thinking power and the foundational calculative ability but also bring up the interest on the activity of establishing a new problem solving strategy.

• International Journal of Railway
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• v.8 no.2
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• pp.50-54
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• 2015

The primary function of the trackbed in a conventional railway track system is to decrease the stresses in the subgrade to be in an acceptable level. A properly designed trackbed layer performs this task adequately. Many design procedures have used assumed and/or are based on critical stiffness values of the layers obtained mostly in the field to calculate an appropriate thickness of the sublayers of the trackbed foundation. However, those stiffness values do not consider strain levels clearly and precisely in the layers. This study proposes a method of computation of stiffness that can handle with strain level in the layers of the trackbed foundation in order to provide properly selected design values of the stiffness of the layers. The shear modulus values are dependent on shear strain level so that the strain levels generated in the subgrade in the trackbed under wheel loading and below plate of Repeated Plate Bearing Test (RPBT) are investigated by finite element analysis program ABAQUS and PLAXIS programs. The strain levels generated in the subgrade from RPBT are compared to those values from RC (Resonant Column) test after some consideration of strain levels and stress consideration. For comparison of shear modulus G obtained from RC test and stiffness moduli $E_{v2}$ obtained from RPBT in the field, many numbers of mid-size RC tests in laboratory and RPBT in field were performed extensively. It was found in this study that there is a big difference in stiffness modulus when the converted $E_{v2}$ values were compared to those values of RC test. It is verified in this study that it is necessary to use precise and increased loading steps to construct nonlinear curves from RPBT in order to get correct $E_{v2}$ values in proper strain levels.

• School Mathematics
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• v.18 no.2
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• pp.397-423
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• 2016

Mathematics learning motivation is an important variable which is not only the primary goal of learning mathematics but also mediates the effects of the mathematics learning. Nevertheless, the present learning environment is full of impeding factors which reduce learners' motivation to learn mathematics and mathematical self-regulatory efficacy. The purpose of this study is to offer various suggestions for program to enhance and forster mathematics learning motivation based on empirical findings and theories on motivation, self-regulatory learning, regulatory focus, reducing academic stress and math anxiety. The concrete and practical ideas are suggested in terms of mathematical self-regulatory efficacy, learners' characteristics, learning task. The analysis of the effects revealed a positive effect on mathematical self-regulatory learning.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.491-500
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• 2018

The purpose of this study is to identify the types of nursing organization culture recognized by hospital nurses and to confirm the relationship between these nursing organizational culture and professional quality of life. A convenience sampling method was used to collect data from 216 participants who worked in a university hospital in C city, Chungbuk province. Data were analyzed using SPSS / WIN22.0 program. The significant predictors of Compassion Satisfaction, which is a subdivision of the professional quality of life, include Innovation-oriented culture, marital status, and the relationship - oriented culture. As for secondary traumatic stress, it has the significant predictors such as age, task-oriented culture and hierarchy-oriented culture. Burnout also turns out to be affected by the predictors of relationship - oriented culture, clinical career, and hierarchy-oriented culture. Based on these results, to create a innovation-oriented culture and relation-oriented culture within the organization, it is necessary to develop an intervention program for nurses' recognition change and improvement, in addition, studies that test the clinical effects are needed. In order to secure skilled nurses with rich clinical and career abilities, the working environment and treatment should be improved at the organization level.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.233-246
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• 2021

The present study aimed to investigate whether there would be differences in the severity of PTSD symptoms, self and others concepts between trauma types. Among 166 university students, 61 (simple trauma's n = 31, complex trauma's n = 30) finally met the criteria and completed the Life Events Checklist, Impact of the Event Scale-Revised, and the emotional Stroop task. The results were as follows: firstly, PTSD symptoms were higher in complex trauma group than single trauma group. Secondly, response time in the complex trauma group was longer in the condition that the negative word related to 'self' was presented for 2 seconds compared to the single trauma group. These results suggest that the complex trauma group has different features at least in the severity of PTSD symptoms and the concept of the self, compared with the single trauma group. Finally, the therapeutic implications and limitations of the study were discussed.