• Earthquakes and Structures
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• v.22 no.1
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• pp.39-51
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• 2022

The axial compression behavior of nine self-compacting concrete columns confined with CFRP-PVC spirals was studied. Three parameters of spiral reinforcement spacing, spiral reinforcement diameter and height diameter ratio were studied. The test results show that the CFRP strip and PVC tube are destroyed first, and the spiral reinforcement and longitudinal reinforcement yield. The results show that with the increase of spiral reinforcement spacing, the peak bearing capacity decreases, but the ductility increases; with the increase of spiral reinforcement diameter, the peak bearing capacity increases, but has little effect on ductility, and the specimen with the ratio of height to diameter of 7.5 has the best mechanical properties. According to the reasonable constitutive relation of material, the finite element model of axial compression is established. Based on the verified finite element model, the stress mechanism is revealed. Finally, the composite constraint model and bearing capacity calculation method are proposed.

• Informatization Policy
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• v.22 no.4
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• pp.91-104
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• 2015

This study tests the effects of differential association, definitions, differential reinforcement and imitation from social learning theory in the explanation of university students' crimes in social network services. In addition, this study tests the interaction effects between social learning factors and other factors such as low self-control, subcultural environment, and crime opportunity for the integrated approach. Using data from 486 university students in Seoul, results show that both definition and imitation have significant influences on crimes, even though differential association and differential reinforcement factors have no significant influences on crimes in social network services. Results also reveal that there are significant interaction effects between definition and subcultural environment, which meana that definition has a strong effect on crimes in high subcultural environment. In addition, it is found that reinforcement has also a strong effect on crimes in high crime opportunity and that interaction effect between imitation and low self-control is significant, which means that imitation has a strong effect on crimes in low self-control students.

• Korean Journal of Adult Nursing
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• v.26 no.1
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• pp.34-45
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• 2014

Purpose: The purpose of this study was to investigate the effect of laughter therapy and cognitive reinforcement program on self-efficacy, depression and cognitive functions of the elderly with mild cognitive impairments (MCI). Methods: The study design was a non-equivalent control group pre and posttest design. Thirty-six subjects over the age of 65 with a diagnosis of mild cognitive impairment were assigned either to a treatment or a comparison group. Data were collected from February 7 to March 27, 2012 in the dementia supporting center. An eight week treatment program that included laughter therapy coupled with a cognitive reinforcing program including hand exercise, laughter dance routine, laughter technic and cognitive training for attention, memory, orientation and execution skill. Results: MoCA-K (t=-6.86, p<.001) and Stroop test CW correct (t=-2.54, p=.008), self-efficacy (t=-3.62, p=.001) in the treatment group were significantly higher than those of the comparison group. Reported depression (t=2.29, p=.014), Stroop test CW error (U=53.50, p<.001) in the treatment group was significantly less than the comparison group. Conclusion: In this study, the treatment was effective in improving self-efficacy, cognitive function and reducing depression in the elderly with MCI.

• The Journal of Information Systems
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• v.21 no.3
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• pp.163-186
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• 2012

With the development of Internet and transition to information society, social capital is expanding to online from the traditional offline context. Especially with the widespread of social network service(SNS) the number of SNS users is increasing sharply and the importance of online social capital has been more and more significant. Most studies on social capital focused on organizational aspects but few studies have payed attention to personal aspect. Empirical studies on the relation between SNS and social capital were seldom conducted in previous studies. Based on the theory of social capital this study targets on the relationship formed through SNS and analyzes on how the relationship affects the perceived social capital. In this study 'self-presentation', 'playfulness' and 'critical mass' are posited as the antecedent factors of 'SNS usage'. This study proposes a research model to examine the effect of 'SNS usage' on 'relationship reinforcement', 'relationship building' and 'perceived social capital'. According to the results of empirical analysis, 'self-presentation', 'playfulness' and 'critical mass' can generate significant positive influence on 'SNS usage'. It also confirms not only the effect of 'relationship reinforcement' and 'relationship building' formed through SNS on 'perceived social capital' but also relationship between the social capital formation and SNS usage. The outcome obtained in this study can be applied in developing SNS services.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.183-190
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• 2020

Purpose : The purpose of this study was to investigate the effect of increased gait function enhancement exercise in three adolescent convulsive cerebral palsy sinuses on children's large movement function, balance and gait function, self-efficacy, and guardian attitude. Methods : The purpose of this study was to conduct a program to strengthen trunk muscles and strengthen walking ability 5 times a week for 8 weeks in 3 children with convulsive cerebral palsy in adolescence. The main reinforcement of the program was 20 minutes of muscle strength and 20 minutes of walking on a treadmill five times a week. Exercises were focused on the reinforcement of the flexor muscles of the proprioceptive neuromuscular promotion (PNF) and the extension of the legs in the bridge posture exercise and squat movements. Results : The results of GMFM-88 to determine the effects of this functional enhancement program on the body of children with convulsive cerebral palsy, and PBS & TUG to determine the effects of balance and gait ability were improved. In addition, parenting attitudes of guardians, self-efficacy of children, and self-efficacy of parents increased positively due to mental consequences. Conclusion : The results of GMFM-88 to determine the effects of this functional enhancement program on the body of children with convulsive cerebral palsy, and PBS & TUG to determine the effects of balance and gait ability were improved. In addition, parenting attitudes of guardians, self-efficacy of children, and self-efficacy of parents increased positively due to mental consequences.

• Structural Engineering and Mechanics
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• v.67 no.2
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• pp.155-163
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• 2018

The Early-age construction loading and changing properties of concrete, especially in the multi-story structures can affect the slab deflection, significantly. Based on previously conducted experiment on eight simply-supported one-way slabs this paper investigates the effect of concrete type, fiber type and content, loading value, cracking moment, ultimate moment and applied moment on the instantaneous deflection of Self-Compacting Concrete (SCC) slabs. Two distinct loading levels equal to 30% and 40% of the ultimate capacity of the slab section were applied on the slabs at the age of 14 days. A wide range of the existing models of the effective moment of inertia which are mainly developed for conventional concrete elements, were investigated. Comparison of the experimental deflection values with predictions of the existing models shows considerable differences between the recorded and estimated instantaneous deflection of SCC slabs. Calculated elastic deflection of slabs at the ages of 14 and 28 days were also compared with the experimental deflection of slabs. Based on sensitivity analysis of the effective parameters, a new model is proposed and verified to predict the effective moment of inertia in SCC slabs with and without fiber reinforcing under two different loading levels at the age of 14 days.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3515-3524
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• 2023

A reinforcement learning framework is proposed for the control problem of outlet steam pressure of the once-through steam generator(OTSG) in this paper. The double-layer controller using Proximal Policy Optimization(PPO) algorithm is applied in the control structure of the OTSG. The PPO algorithm can train the neural networks continuously according to the process of interaction with the environment and then the trained controller can realize better control for the OTSG. Meanwhile, reinforcement learning has the characteristic of difficult application in real-world objects, this paper proposes an innovative pretraining method to solve this problem. The difficulty in the application of reinforcement learning lies in training. The optimal strategy of each step is summed up through trial and error, and the training cost is very high. In this paper, the LSTM model is adopted as the training environment for pretraining, which saves training time and improves efficiency. The experimental results show that this method can realize the self-adjustment of control parameters under various working conditions, and the control effect has the advantages of small overshoot, fast stabilization speed, and strong adaptive ability.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.341-358
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• 2024

This paper reports several plane-strain trapdoor tests conducted to investigate the effects of reinforcement on soil arching development under localized surface loading with a loading plate width three times the trapdoor width. An analogical soil composed of aluminum rods with three different diameters was used as the backfill and Kraft paper with two different stiffness values was used as the reinforcement material. Four reinforcement arrangements were investigated: (1) no reinforcement, (2) one low stiffness reinforcement R1, (3) one high stiffness reinforcement R2, and (4) two low stiffness reinforcements R1 with a backfill layer in between. The stiffness of R2 was approximately twice that of R1; therefore, two R1 had approximately the same total stiffness as one R2. Test results indicate that the use of reinforcement minimized soil arching degradation under localized surface loading. Soil arching with reinforcement degraded more at unloading stages as compared to that at loading stages. The use of stiffer reinforcement had the advantages of more effectively minimizing soil arching degradation. As compared to one high stiffness reinforcement layer, two low stiffness reinforcement layers with a backfill layer of certain thickness in between promoted soil arching under localized surface loading. Due to different states of soil arching development with and without reinforcement, an analytical multi-stage soil arching model available in the literature was selected in this study to calculate the average vertical pressures acting on the trapdoor or on the deflected reinforcement section under both the backfill self-weight and localized surface loading.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.409-414
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• 2002

This study is intended to develop the self water proof admixture for durability concrete by anti-corrosion inhibitor. Chloride induced corrosion of reinforcement is one of the main factor which cause the deterioration of concrete structure. When the substitute anti-corrosion agents for a part of self waterproofing agent, the corrosion-proof increases for the increased water proofing capacity. And proper self waterproofing agent by cement weight in concrete was generally positive effect to concrete compressive strength, slump, freezing and thawing resistance. Also, permeability and absorption show a straight decrease when self waterproofing agent is added.

• Advances in concrete construction
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• v.11 no.3
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• pp.193-206
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• 2021

Extensive research has been conducted on the basic mechanical property and structural applications of engineered cementitious composites (ECC). Despite the high tensile ductility and high toughness of ECC, transverse steel reinforcement is still necessary to confine ECC for high performance. However, limited research has examined performance of ECC confined with practical amount of transverse reinforcement. This paper presents the results of axial compression tests on 14 square ECC columns and 4 conventional concrete columns (used as control specimens) with transverse reinforcement. The test variables were spacing, configuration (square ties or square and diamond shape ties), and yield strength of stirrups. The test showed that ECC columns confined with steel stirrup had good compressive ductility, and the stirrup spacing had the greatest effect on the compressive performance. The self-confinement effect of ECC results in a more uniform but slower expansion of the whole column compared with CC ones. The test results are then compared against the predictions from a number of existing models for conventional confined concrete. It is indicated that these models fail to predict the axial strains at peak axial stress and the trend of the stress-strain curve of steel stirrups-confined ECC with sufficient accuracy. Several new equations are then proposed for the compressive properties of steel-confined ECC based on test results and potential approaches for future studies are proposed.