• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.454-461
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• 2001

Dynamic responses of a multi-span simply supported bridge are examined under seismic excitations considering damage of bearings. An idealized mechanical model which can consider components such as pounding, friction at the supports, abutment-soil interaction, rotational and translational motions of foundations, and the nonlinear pier motions, is developed to analyze the effects due to damage of bearings. It is assumed that the bearing's response after failure can be expressed with a sliding model with a friction coefficient between the superstructure and the pier top. It is found that the global seismic behaviors are significantly influenced by the damage of bearings and the damage of bearings may lead to unseating failure at unpredicted supports. Therefore, It can be concluded that detailed seismic response analyses of bridge systems considering damage of bearings is required for the purpose of the seismic safety evaluation.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.33-39
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• 2008

The purpose of this study is not only to evaluate the stress behavior of tubes in superheater in HRSG during the load change operation but also to find root causes of failure from stress behavior. Firstly, temperature during operation was collected to perform stress analysis from actual HRSG. Part load and full load stress analysis which can be represented as the whole load change operations were performed using commercial finite element software. The possibility that can lead to tubes failure is found by stress analysis and its results is compared with metallurgical mircrostructure of failed tube which was taken from actual HRSG.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1213-1216
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• 1998

This paper presents the result of a feasibility study for the prediction method of fault symptoms on 22.9kV distribution line. In this paper, real distribution data was collected and analyzed to isolate failure signatures or parameters which were distinct behaviors before and after failure incident. A new strategy of analysis-based (event-date concept) prediction algorithm for the distribution insulators and a developed model system were also discussed.

• Korean Journal of Child Studies
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• v.23 no.4
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• pp.119-136
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• 2002

This study examined teacher's perceptions of the psychosocial adjustment and problem behaviors of institutionalized children compared with home reared children. Data were collected from the teachers of institutionalized children in elementary and secondary schools. The majority of institutionalized children were regarded as not very much different from home reared children. Still, findings from this study lead to conclusions that institutionalization is likely to elevate children's risk for adjustment problems such as social withdrawal, peer violence, and academic failure. Findings that the ratio of institutionalized children attending school decreased with age lead to speculation that failure in psychosocial adjustment may lead to to dropping out of school. Finally, a practical framework for the optimal development of institutionalized children is provided, with emphasis on school-community based interventions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.47-48
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• 2017

The substrate behavior response testing outlined in KS F 2622 evaluates the leakage cause of waterproofing membrane systems when subjected to the concrete joint load behaviors by removing the waterproofing layer after testing, relying mostly on visual observation and subjective analysis. A non-destructive leakage cause and failure type analysis method is proposed currently in this study by the means of detecting leakage paths using thermal emission imaging systems. Test specimens are placed in varying temperature conditions after the concrete joint movement testing and are scanned using the thermal emission camera to determine the location and dimension of the adhesion failure/leakage path beneath the waterproofing membranes.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.262-267
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• 2016

In this paper, to design Human Powered Aircraft(HPAC) with high aspect ratio wing which behave with large displacement under lift distribution causing a failure itself, then steel wire has been designed to prevent its failure. unit load method is used to calculate reaction force on wire and Optimal Triangle(OPT) membrane is employed to analyze its main wing spar with large displacement. EDISON CSD solver, linear static analysis and co-rotational nonlinear static anaysis both using OPT membrane produce behaviors of beam for each case of wire location about main wing spar, and aerodynamic coefficient also, by using aerodynamic analysis tool.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.737-741
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• 2000

Portable communication devices such as laptop computers suffer impact-induced failure in their usage. Drop/impact performance of these products is one of important concerns of product design. Because of the small size of this kind of electronics products, it is very expensive, time-consuming and difficult to conduct drop tests to directly detect the failure mechanism and identify their drop behaviors. Finite element analysis provides a vital, powerful vehicle to solve the problems. The models are created with HYPERMESH, and the analysis is carried out with LS-DYNA3D. The analysis is focused on HDD impact behavior in acceleration peak values.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.649-655
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• 2019

Fracture behaviors of SCM435 high strength bolt have been studied including macroscopic and microscopic fracture observation, Energy Dispersive X-ray Spectroscopy, Vickers hardness test and applied stress evaluation. cracks (ratchet marks) were generated by the repetitive loads acting on the bolts, initial stress of bolt and the stress concentration. The applied stress was found to be slightly higher than the fatigue limit of the material. The initial stress of bolt must be removed, and the mold temperature during the process must be maintained by room temperature. Bolts are recommended to be peened to improve fatigue limit.

• Korean Journal of Metals and Materials
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• v.49 no.10
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• pp.754-759
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• 2011

In this study, the interlaminar fracture behaviors of laminated GFRP composites were investigated, and the results could be used for damage tolerance design based on fracture mechanics. Three types of laminated GFRP composites that can be used as high voltage insulating materials in magnet systems were fabricated in order to study the interlaminar fracture behavior according to the molding process. The values of interlaminar fracture toughness for the VPI, prepreg, and HPL laminate were $1.9MPa{\cdot}^{1/2}$, $1.7MPa{\cdot}^{1/2}$, and $2.2MPa{\cdot}^{1/2}$, respectively. HPL laminate showed the best fracture resistance. The failure modes of HPL and VPI were similar to that of an adhesive joint, and prepreg laminates showed partial cohesive failure mode due to internal voids.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.88-93
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• 2023

In software engineering, requirement analysis is an important task throughout the process and takes up a high proportion. However, factors that fail to analyze requirements include communication failure, different understanding of the meaning of requirements, and failure to perform requirements normally. To solve this problem, we derived actors and behaviors using morpheme analysis and BERT algorithms in the Korean requirement document and constructed them as ontologies. A chatbot system with ontology data is constructed to derive a final system event list through Q&A with users. The chatbot system generates the derived system event list as a requirement diagram and a requirement specification and provides it to the user. Through the above system, diagrams and specifications with a level of coverage complied with Korean requirement documents were created.