• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.497-512
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• 2006

In this paper, a simple but effective analysis procedure to estimate seismic capacities of multi-span continuous bridge structures is proposed on the basis of modal pushover analysis considering all the dynamic modes of structure. Unlike previous studies, the proposed method eliminates the coupling effects induced from the direct application of modal decomposition by introducing an identical stiffness ratio and an approximate elastic deformed shape. Moreover, in addition to these two introductions, the use of an appropriate distributed load {P} makes it possible to predict the dynamic responses for all kinds of bridge structures through a simpler analysis procedure. Finally, in order to establish the validity and applicability of the proposed method, correlation studies between rigorous nonlinear time history analysis and the proposed method are conducted for multi-span continuous bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3B
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• pp.239-245
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• 2009

Levees, the hydro-engineering structure, are similar to earth dams in aspects of shape and structure. However, they are different from earth dams in the external force conditions. As a levee is the structure that is complexly affected by the flow and the water stage in the river, it may be unreasonable to analyze the seepage safety as previous studies derived from the neglect of river flow. In this study, an experiment was conducted to investigate flow structures in a trapezoidal open-channel and the influence of the channel flow on the seepage through a levee. Flow structures in a trapezoidal open-channel were distinguished from a rectangular open-channel such as velocity and bottom shear stress distributions. In case with the flow velocity of 0.5 m/s, seepage water heads were higher 10 percent as compared with the stagnant case. This result is caused by dynamic heads, secondary currents, turbulent fluctuation forces, and various physical factors. It is suggested that external force boundary considered in terms of the flow as well as the water stage is proper to seepage analyses.

• Geomechanics and Engineering
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• v.34 no.3
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• pp.233-250
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• 2023

This paper investigates the flexural analysis of isotropic, transversely isotropic, and laminated composite plates using a new higher-order normal and shear deformation theory. In the present theory, only five unknown functions are involved compared to six or more unknowns used in the other similar theories. The developed theory does not need a shear correction factor. It can satisfy the zero traction boundary conditions on the top and the bottom surfaces of the plate as well as account for sufficient distribution of the transverse shear strains. The thickness stretching effect is considered in the computation. A simply supported was considered on all edges of the plate. The plate is subjected to uniform and sinusoidal distributed load in the static analysis. Laminated composite, isotropic, and transversely isotropic plates are considered. The governing equations are obtained utilizing the virtual work principle. The differential equations are solved via Navier's procedure. The results obtained from the developed theory are compared with other higher-order theories considered in the previous studies and 3D elasticity solutions. The results showed that the proposed theory accurately and effectively predicts the bidirectional bending responses of laminated composite plates. Several parametric studies are presented to illustrate the various parameters influencing the static response of the laminated composite plates.

• Mood & Emotion
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• v.9 no.1
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• pp.30-36
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• 2011

Purpose : Anxiety disorder and depressive disorder are often comorbid with each other, and the comorbidity is associated with poorer psychiatric outcome, resistance to treatment, increased risk for suicide, greater chance for recurrence. We aimed to investigate the comorbidity of anxiety disorder in Korea. Method : Subjects were total of 867 depressed patients recruited CRESCEND-K multicenter trial. We used SCID (Structured Clinical Interview for DSM - IV) to find comorbidity of anxiety disorders in depressed patient. Results : Of 867 patients, total 8.2% had anxiety disorder. Proportion of anxiety disorder Not Otherwise Specified was 3.5%, panic disorder was 1.7%, generalized anxiety disorder was 1.1%, post traumatic stress disorder was 0.9%, obsessive compulsive disorder was 0.6%, social phobia was 0.4%. Conclusion : In this study, anxiety disorder in depression were measured at a low comorbidity rate in compare to previous studies. Selection bias, use of antidepressants at registration, severity of depression symptoms, and point of SICD administration seems to have affected these results. It is probable that comorbidity evaluation would be more precise if shorter, structured interviews such as M. I.N.I.-Plus were used during first clinical interview for depression diagnosis.

• Geomechanics and Engineering
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• v.35 no.5
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• pp.525-538
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• 2023

The development of a city is closely linked to the construction and operation of its subway system. However, constructing a new subway tunnel under an existing station is an extremely complex task, and the deformation characteristics and mechanical behavior of the new subway tunnel during the excavation process can greatly impact the normal operation of the existing station. Although the previous studies about the case of underpass engineering have been carried out, there is limited research on the condition of a newly-built subway tunnel that closely undercrossing an existing station with zero distance between them. Therefore, this study analyzes the deformation law and mechanical behavior characteristics of the preliminary lining of the underpass tunnel during the excavation process based on the real engineering case of Chengdu Metro Line 8. This study also makes an in-depth comparison of the influence of different excavation methods on this issue. Finally, the accuracy of numerical simulation is verified by comparing it with on-site result. The results indicate that the maximum bending moment mainly occurs at the floor slab of the preliminary lining, while that of the ceiling is small. The stress state at the ceiling position is less affected by the construction process of the pilot tunnel. Compared to the all-in-one excavation method, although the process of partial excavation method is more complicated, the deformation of preliminary lining caused by it is basically less than the upper limit value of the standard, while that of the all-in-one excavation method is beyond standard requirements.

• Composites Research
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• v.36 no.5
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• pp.315-320
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• 2023

In the manufacturing process of thermosetting carbon fiber composite materials using an autoclave, the internal temperature changes according to the set temperature cycle. This temperature change causes the resin in the composite material to cure. Heat is generated through the chemical reaction of the resin, which can result in a difference between the temperature inside the autoclave and the temperature of the composite material. Previous research assumed that the temperatures of the composite material and the autoclave were the same and analyzed to predict the residual stress and thermal deformation after manufacturing. However, these stresses and deformations depend on the temperature and degree of cure of the composite material. Therefore, this study verifies a thermal-chemical model analysis technique that takes into account the heat generated by the chemical reaction of the resin to accurately calculate the temperature and degree of cure. Additionally, case studies were conducted for different thicknesses to investigate whether this model exhibits similar trends across varying thicknesses.

• Anxiety and mood
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• v.19 no.2
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• pp.61-68
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• 2023

Objective : The purpose of this study was to investigate the associations between psychosocial factors and the mask-wearing behavior after deregulation of COVID-19 quarantine guidelines among adults in Korea. Methods : We collected data (345 subjects) from online questionnaire survey. The questionnaire included the Korean version of the Patient Health Questionnaire-9, the Korean version of fear of COVID-19 Scale, the Korean version of the Patient Health Questionnaire-15, Korean versions of the Perceived Stress Scale, and measurement tools adapted from previous studies for COVID-19 risk perception, social stigma, and appearance interest of subjects. We analysed data using SPSS version 23.0 for descriptive statistics, chi-square test, and logistic regression analysis. Results : People with cohabitant or mask-wearing tendency before COVID-19 pandemic had a higher rate of mask-wearing than those who were not. Subjects reporting higher level of social stigma (OR=1.154, 95% CI 1.049-1.270) and COVID-19 anxiety (OR=1.072, 95% CI 1.007-1.141) were more likely to report maskwearing behavior. Conclusion : From the results, appropriate intervention to those who fear social stigma and are anxious to the infectious diseases will be needed. Additionally, providing policies and guidelines that consider cohabitants and offering continuous education with information of disease to the public are also expected to helpful for recovery of daily life from infectious diseases.

• ALGAE
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• v.38 no.4
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• pp.283-294
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• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• Steel and Composite Structures
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• v.50 no.3
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• pp.265-280
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• 2024

The collapse behavior observed in single-story beam-column assembly (SSBCA) do not accurately represent the actual overall stress characteristic of multi-story frame structure (MSFS) under column loss scenario owing to ignoring the interaction action among different stories, leading to a disconnection between the anti-collapse behaviors of "components" and "overall structures", that is, the anti-collapse performance of frame structures with two different structural scales has not yet formed a combined force. This paper conducts a numerical and theoretical study to explore the difference of the collapse behaviors of the SSBCA and MSFS, and further to reveal the internal force relationships and boundary constraints at beam ends of models SSBCA and MSFS. Based on the previous experimental tests, the corresponding refined numerical simulation models were established and verified, and comparative analysis on the resistant-collapse performance was carried out, based on the validated modeling methods with considering the actual boundary constraints, and the results illustrates that the collapse behaviors of the SSBCA and MSFS is not a simple multiple relationship. Through numerical simulation and theoretical analysis, the development laws of internal force in each story beam under different boundary constraints was clarified, and the coupling relationship between the bending moment at the most unfavorable section and axial force in the composite beam of different stories of multi story frames with weld cover-plated flange connections was obtained. In addition, considering the effect of the yield performance of adjacent columns on the anti-collapse bearing capacities of the SSBCA and MSFS during the large deformation stages, the calculation formula for the equivalent axial stiffness at the beam ends of each story were provided.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.329-337
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• 2024

The purpose of this study was to investigate the effect of aromatherapy planned behavior on behavioral intention using the theory of planned behavior of attitude, subjective norm, and perceived behavioral control as factors of the theory of planned behavior. The behavioral intention of aromatherapy planned behavior was analyzed to have a significant positive causal relationship between the independent variables of attitude, subjective norm, and perceived behavioral control on the behavioral intention of aromatherapy. As a result of testing Hypothesis 1, "Aromatherapy planned behavior will have an effect on behavioral intention," previous research confirmed that the greater the attitude, perceived behavioral control, and subjective norm during aromatherapy planned behavior, the higher the participation intention. The verification was consistent with similar results between this study and this study. These results suggest that aromatherapy planned behavior will contribute to increasing aromatherapy's market share, reducing stress, and improving health through behavioral intention.