• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.117.2-117
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• 2002

• Journal of the Korean housing association
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• v.17 no.2
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• pp.77-85
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• 2006

This study aims to propose the comprehensive evaluation of performance multi-family housing. Most of the existing studies for the reproduction have evaluated by the safety of structure. Therefore those pass over the functional factors which is important for the evaluation of residential qualities. This study represents that the reproduction renovation should not be secured the safety of structure but established the quality of lift. And questionnaire asking expert's opinion also supplemented. As a result, the item for examination and the weight for evaluation are suggested in functional deterioration. The results of this study are summarized as follows: 1. Existent redevelopment criteria are not appropriate to decide the environmental comfort, the vital function of housing and the residential management finance. 2. The future criteria have to evaluate the existing environmental comfort, be reconstructed to put first general deterioration. 3. Evaluation elements was extracted throughout the document research, evaluation elements analysis system was separated in residential area, suburb of dwellings, community, and housing complexity environmental assesment, 4. Each category of influence ratio was extracted to assess total deterioration throughout the expert question survey. 5. Each category analysed (1) $0{\sim}30%$: function is good (unnecessary to improve) (2) $31{\sim}40%$: average (necessary of partial improvement) (3) $41{\sim}59%$: bad (necessary of total improvement) (4) $60{\sim}100%$: the worst (unable to improve throughout the repair)

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.256-258
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• 2005

EMU system is system that o(for target performance and function because various lower part system such as vehicles, signaling, power supply, rail track is consisted as complex. It is important first of all that describe correctly system requirement until configuration of system, design, manufacture, installation and test verification so that the complicated urban transit system is to act safety and reliable and to display target performance and function properly. The system requirement assist the system developer to comprehensive the performance and function of system in basic design. Therefore, In this paper wishes to study way to analyze system of system requirement and apply to Urban transit.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1179-1180
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• 2007

Urban transit is system that offer target Performance and function because various lower part system such as vehicles, signaling, power supply, rail track is consisted as complex. It is important first of all that describe correctly system requirement until configuration of system, design, manufacture, installation and test verification so that the complicated urban transit system is to act safety and reliable and to display target Performance and function properly. The system requirement assist the system developer to comprehensive the performance and function of system in basic design. Therefore, In this paper wishes to study way to analyze system of system requirement and apply to Urban transit.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.296-298
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• 2005

Urban transit is system that offer target Performance and function because various lower part system such as vehicles, signaling, power supply, rail track is consisted as complex. It is important first of all that describe correctly system requirement until configuration of system, design, manufacture, installation and test verification so that the complicated urban transit system is to act safety and reliable and to display target Performance and function properly. The system requirement assist the system developer to comprehensive the performance and function of system in basic design. Therefore, In this paper wishes to study way to analyze system of system requirement and apply to Urban transit.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.46-48
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• 2014

This paper compared and demonstrated the performance of the earth plate for conventional type and early streamer discharging type developed a new plate in order to improve the performance of the ground plate for use in grounding. The results obtained are shown below; early streamer discharge earth plate was high 5 kV on DC flashover voltage and corona discharge current was higher than about 2 times under the same test conditions compared to the conventional earth plate. From the experiential result, streamer discharge earth plate had a function of rapid inflow/out flow than the general ground plane because of by corona discharge current to be generated in the sharp serrated in formed the ground plane when strike current occurred. In the future, the newly developed early streamer discharge ground plate would be beneficial for grounding work to be widely used to promote the convenience and economy of construction.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1224-1228
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• 2009

The korean tilting train can increase the whole operating speed at a curved railroad, reducing the lateral acceleration with the tilting mechanism unlike the train developed before. However, increasing operating speed on the curved section, may cause safety problem of train travel. In general, a suspension system has important effects on driving safety. Therefore, optimization of suspension system is necessary to secure the safety of the tilting train. In this study, the tilting train suspension system has been optimized using Design of Experiments (DOE). First, the design parameter is selected using sensitivity analysis. A lateral acceleration which affects on the driving safety is chosen as the objective function. And the Design of Experiments (DOE) is used for optimization. As a result, new design parameters which show better performance than the existing suspension system has been suggested.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.

• Smart Structures and Systems
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• v.33 no.2
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• pp.133-143
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• 2024

Piezoelectric (PZT) actuators have been widely used in precision positioning fields for their excellent displacement resolution. However, due to the inherent characteristics of piezoelectric actuators, hysteresis has been proven to greatly reduce positioning performance. In this paper, five mathematical hysteretic models based on activation function are proposed to characterize the nonlinear hysteresis characteristics of piezoelectric actuators. Then the performance of the proposed models is verified by particle swarm optimization (PSO) algorithm and the experiment data. Thirdly, the fitting performance of the proposed models is compared with the classical Bouc-Wen model. Finally, the performance of the five proposed models in modelling hysteresis nonlinearity of piezoelectric drivers is compared, in terms of RMSE, MAPE, SAPE and operation efficiency, and relevant suggestions are given.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.159-166
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• 2023

Due to the aging workforce in the construction industry in South Korea, the accident rate has been increasing. The cognitive abilities of older workers are closely related to both safety incidents and labor productivity. Therefore, there is a need to improve cognitive abilities through personalized training based on cognitive assessment results, using cognitive training content, in order to enable safe performance in labor-intensive environments. The provided cognitive training content includes concentration, memory, oreintation, attention, and executive functions. Difficulty levels were applied to each content to enhance user engagement and interest. To stimulate interest and encourage active participation of the participants, the difficulty level was automatically adjusted based on feedback from the MMSE-DS results and content measurement data. Based on the accumulated data, individual training scenarios have been set differently to intensively improve insufficient cognitive skills, and cognitive training programs will be developed to reduce safety accidents at construction sites through measured data and research. Through such simple cognitive training, it is expected that the reduction of accidents in the aging construction workforce can lead to a decrease in the social costs associated with prolonged construction periods caused by accidents.