• Earthquakes and Structures
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• v.2 no.4
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• pp.323-336
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• 2011

The problem of reconstruction of complete building response from a limited number of response measurements is considered. The response at the intermediate degrees of freedom is reconstructed by using piecewise cubic Hermite polynomial interpolation in time domain. The piecewise cubic Hermite polynomial interpolation is preferred over the spline interpolation due to its trend preserving character. It has been shown that factorization of response data in variable separable form via singular value decomposition can be used to derive the complete set of normal modes of the structural system. The time domain principal components can be used to derive empirical transfer functions from which the natural frequencies of the structural system can be identified by peak-picking technique. A reduced-rank approximation for the system flexibility matrix can be readily constructed from the identified mass-orthonormal mode shapes and natural frequencies.

• Earthquakes and Structures
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• v.16 no.4
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• pp.415-423
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• 2019

Near-fault ground motions can impose particularly high seismic demands on structures due to the pulses that are typically observed in the velocity time-histories. In this study it is empirically found that the critical response can be estimated from the directions corresponding to the maximum (max) or minimum (min) pulse-energy. Determination of the pulse-energy requires removing of the high-frequency content. For achieving this, the wavelet analysis and the least-square-fitting (LSF) algorithm are adopted. Results obtained by the two strategies are compared and differences between them are analyzed. Finally, the relationship between the critical response and the response derived from directions having the max or min pulse-energy confirms that using the pulse-energy for deriving the critical response of the building structures is reasonable.

• Transactions of Materials Processing
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• v.30 no.1
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• pp.27-34
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• 2021

In this study, response surface method (RSM) was used in modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goals of optimization were the maximum forming angle, minimum thickness reduction, and minimum surface roughness, with varying values in response to changes in production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model for modeling the variations in the forming angle, thickness reduction, and surface roughness in response to variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process based on experimental design. The results showed that RSM can be effectively used to control the forming angle, thickness reduction, and surface roughness.

• Steel and Composite Structures
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• v.48 no.3
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• pp.353-365
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• 2023

Shape memory alloys (SMAs) have emerged as a novel functional material that is being increasingly applied in diverse fields including medical, aeronautical and structural engineering to be used in the active, passive and semi-active structural control devices. This paper is mainly aimed at evaluating the ductility and response modification factor of the steel plate shear wall (SPSW) frames with and without the Ni-Ti shape memory alloys. To this end, different configurations were utilized, in which the walls were used in the first, third, middle, and all stories. The models were numerically analyzed using OpenSees Software. The obtained results indicate that improving the shape memory properties of alloys can greatly enhance the ductility and response modification factor. Furthermore, the model whose first and third stories are equipped with the SMA shear wall was found to be 290% more ductile, with a greater response modification factor compared to the unequipped frame.

• Journal of Marine Life Science
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• v.3 no.2
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• pp.87-95
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• 2018

To investigate effects of starvation on physiological changes, stress response, and survival of cobitid loach (Misgurnus anguillicaudatus) exposed to sodium nitrite (NaNO₂), a 4-week experiment was conducted. Fewer fish survived in the starved group than those in the fed group during the experiment. Starvation resulted in growth retardation, leading to differences in body length and body depth between fed and starved groups. The fed gorup continued to grow and remained in good condition. Blood chemical analysis (plasma cortisol and glucose) showed significant differences in stress response to nitrite exposure between fed and starved groups (p < 0.05). These results suggest that all parameters employed in this study to assess effects of starvation with NaNO₂ stress are useful information for researching nutritional status in cobitid loach.

• Korean Journal of Artificial Intelligence
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• v.12 no.2
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• pp.25-33
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• 2024

This study examines the relationship between customer satisfaction and management response in the hotel industry amid the COVID-19 pandemic. By applying regression analysis and topic modeling to consumer reviews on online platforms, we assess how consumer perceptions and management behaviors have shifted since the onset of the pandemic. The findings reveal a significant decline in customer satisfaction linked to COVID-19. Significantly, while the pandemic has reduced overall customer satisfaction levels, high response rates and high review-response content similarity mitigate the impact of the crises. These results highlight the critical need for hotel managers to continuously monitor online reviews and adapt their engagement strategies to maintain and enhance customer satisfaction during ongoing and future crises. This research not only corroborates existing theories on customer satisfaction but also exposes novel dynamics introduced by the pandemic, offering new insights for effective customer relationship management in turbulent times.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.3956-3972
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• 2023

The floor response spectrum (FRS) is used to evaluate the seismic demand of equipment installed in nuclear power plants. In the conventional design practice of NPP structure, the FRS is simplified using the lumped-mass stick model (LMSM), assuming the floor slab as a rigid diaphragm. In the present study, to study the variation of seismic response in a floor, the FRSs at different locations were generated by 3-D finite element model, and the response was compared to that of the rigid diaphragm model. The result showed that the FRS significantly varied due to the large opening in a floor, which was not captured by the rigid diaphragm model. Based on the result, seismic fragility analysis was performed for the anchorage of a heat exchanger, to investigate the effect of location-dependent FRS disparity on the high confidence low probability of failure (HCLPF).

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.625-628
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• 2007

갈수록 복잡화, 대량화되고 있는 시스템의 성능은 유지하면서 User Response Time 을 단축시키는 Tuning 은 투자 대비 이익률(ROI : Return On Investment)에 탁월한 효과를 가져온다는 점에서 중요시 되고 있다. 본 연구는 SAP R/3 System 환경에서 Tuning 통한 User Response Time 감소를 위하여 Query 분석 및 Table Index 생성, Program Logic 수정, Parallel Processing, SAP R/3 System 의 고유 기능인 Notes 적용을 통한 User Response Time 감소 기법을 제시한다.

• Fire Protection Technology
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• s.10
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• pp.9-12
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• 1991

As the present idustry is devolping rapidly, automatic sprinklers continue to play a key role in modern fire protection. But the technical basis and methods of measurement of the thermal response of sprinklers are not studying in our country. Therefore, the purpose of this paper is to analyze the thermal response characteristics and condition parameters of automatic sprinkler head.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.314-317
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• 2007

Automotive rear subframe of aluminum tube was developed by using hydroforming process, based on the numerical analysis and physical tryouts. In the previous study, the effect of prebending was evaluated on the basis of forming limit diagram which had been obtained from free bulging, T-shape forming and cross-shape forming, using the developed tube hydroformability testing system. In order to get the sound products, appropriate internal pressure is to be imposed corresponding to the axial feeding. In this study, the loading path, the combination of internal pressure and axial feeding during the process, was optimized to ensure minimum thickness variation and dimensional accuracy, by using response surface method.