• Steel and Composite Structures
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• 제38권2호
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• pp.165-176
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• 2021

Existing research on confined concrete filled steel tubular (CCFT) columns has been mainly focused on static or cyclic loading. In this paper, square section CCFT and CFT columns were tested under both static and impact loading, using a 10,000 kN capacity compression test machine and a drop weight testing equipment. Research parameters included bonded and unbonded fiber reinforced polymer (FRP) wraps, with carbon, basalt and glass FRPs (or CFRP, BFRP, and GFRP), respectively. Time history curves for impact force and steel strain observed are discussed in detail. Experimental results show that the failure modes of specimens under impact testing were characterized by local buckling of the steel tube and cracking at the corners, for both CCFT and CFT columns, similar to those under static loading. For both static and impact loading, the FRP wraps could improve the behavior and increase the loading capacity. To analyze the dynamic behavior of the composite columns, a finite element, FE, model was established in LS-DYNA. A simplified method that is compared favorably with test results is also proposed to predict the impact load capacity of square CCFT columns.

• 대한기계학회논문집A
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• 제28권10호
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• pp.1526-1533
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• 2004

The needs of walking assistant device such as the Ankle Foot Orthosis (A.F.O) are getting greater than before. However, most of the A.F.O are generally imported rather than domestic manufacturing. The major reason of high import reliability is the rack of impact properties of domestic commercial products. Therefore, this research is going to focus on the evaluation of impact properties of the A.F.O which has the high import reliability. Unfortunately, these kinds of researches are not performed sufficiently. This research is going to evaluate impact energy behavior in composite materials such as the glass/epoxy (S-glass, [0/90]sub 2S/) and the aramid/epoxy (Kevlar-29, woven type, 8 ply) of ankle foot orthosis. The approach methods were as follows. 1) The history of impact load and impact energy due to the various velocities. 2) Relationship between the deflection and damage shape according to the impact velocities. 3) The behavior of absorbed energy and residual strength rate due to the various impact velocities.

• 대한기계학회논문집A
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• 제26권4호
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• pp.787-793
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• 2002

In this study, a bar impact test of low velocity was carried out to gain an insight into the damage mechanism and sequence induced in alumina plates(AD 85 and AD 90) under impact conditions. An experimental setup utilizing an instrumented long bar impact was devised, that can measure directly the impact force applied to the specimen and supply a compressive contact pressure to the specimen. During the bar impact testing, the influences of the contact pressure applied along the impact direction to the specimen on the fracture behavior were investigated. The measured impact force profiles explained well the damage behavior induced in alumina plates. The higher contact pressure to the specimen led to the less damage due to the suppression of radial cracks due to the increase in the apparent flexural stiffness of plate. It had produced the change of damage pattern developed in the specimen; from the radial cracks to the local contact stress dominant damage. It would contribute to the improvement of the ballistic property in ceramic plates. The observed results showed the following sequence in damage developed: The development of cone crack at impact region, the formation of radial cracks from the rear surface of plate depending on the plate thickness, the occurrence of crushing within the cone envelope and the fragmentation.

• 한국조리학회지
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• 제23권1호
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• pp.10-18
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• 2017

This study examined the positive impact of workplace harassment on the employees' counterproductive work behavior at deluxe hotel in Seoul and Tokyo. The study verified a differentiated influence based on the nationality of the employees. The hypothesized relationships in the model were tested simultaneously by using structural equation modelling. First, isolation/exclusion (${\beta}=.403$), disrespectful behavior (${\beta}=.312$), physical aggression (${\beta}=.245$), and verbal aggression (${\beta}=.133$) had a positive impact on counterproductive work behavior. However, threats/bribes (${\beta}=.091$) did not show a significant impact. Second, no significant moderating effect based on employees' nationality (Korean versus Japanese) was observed in the relationship between the five workplace harassment factors and CWB. This study will investigate workplace harassment perceived by deluxe hotel employees in Korea and Japan, and the obtained data can also be used to help identify realistic plans to reduce workplace harassment between bosses and subordinates at an organizational level.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2011년도 춘계학술대회
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• pp.309-317
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• 2011

Data were collected from employees(N=155) working in manufacturing industry to assess the impact of safety climate on job satisfaction, organizational citizenship behavior, and intention to turnover. Subordinate dimensions of the safety climate measured in our study were management value, immediate supervisor, safety communication, safety training, and safety practice. The results show that management value and immediate supervisor, of safety climate's dimensions, impact on job satisfaction and organizational citizenship behavior. Intention to turnover was influenced by only immediate supervisor.

• 패션비즈니스
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• 제23권6호
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• pp.37-48
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• 2019

This paper aims to stretch the technology acceptance model (TAM) approach by investigating a clothes rental network. One of the understudied geographies of the world economy is the large-scale international trade in clothes, which are consumed by Chinese consumers. An online (www.sojump.com) survey was conducted by including 303 Chinese respondents. Structural equation modeling (SEM) was used to test the proposed hypothesis. The results indicated that external influence has a significant impact on the perceived ease of rental. Furthermore, consumers' perceived ease of rental influences the attitude towards renting, and perceived ease of rental plays a complete mediating role between them. However, external influence has no significant impact on perceived usefulness, and consumers' perceived usefulness has no impact on rental intention. In addition, attitude towards renting works as an indispensable mediation between perception and behavior. This study highlights the role of perception, attitude, behavior on clothes rental, and provides guidance and suggestions for clothes rental platform.

• 감성과학
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• 제26권2호
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• pp.3-12
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• 2023

The present study examines the impact of COVID-19 anxiety on employees' psychological resources and behaviors, drawing on the conservation of resources theory. We also investigate whether flexibility in work contexts has a meaningful effect on employees' responses to the pandemic. A total of 284 working adults participated in an online survey consisting of self-reporting questionnaires that assessed levels of COVID-19 anxiety, vigor, innovative work behavior, and flexible working arrangements. The results showed that the level of vigor mediated the positive relationship between COVID-19 anxiety and innovative work behavior, and the perceived level of flexible working arrangements moderated this mediation effect positively. The findings highlight the importance of considering employees' psychological resources and work arrangements in managing the negative impact of COVID-19-related anxiety. This study provides theoretical and practical implications for organizations to better understand the psychological processes that employees undergo during a crisis. Further research on diverse work settings and cultural backgrounds is needed to expand on the present findings.

• 대한안전경영과학회지
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• 제24권2호
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• pp.51-59
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• 2022

Considering that extant studies on safety behavior have paid insufficient attention to the impact of corporate social responsibility(CSR) on employee's safety behavior. This paper delves into the influence of CSR on safety behavior and its intermediating mechanism such as mediator and moderator. To be specific, the current paper examines the mediating effect of employee's psychological safety in the CSR-safety behavior link, also investigating the moderating effect of ethical leadership in the relationship between CSR and psychological safety. As expected in the hypotheses, the results showed that that CSR has a positive (+) influence on psychological safety, which has a positive (+) impact on safety behavior. Also, employee's psychological safety mediated the association between CSR and safety behavior. Lastly, ethical leadership moderated the CSR-psychological safety link.

• Structural Engineering and Mechanics
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• 제91권1호
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• pp.75-86
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• 2024

In this paper, the porous metal PM-35 is proposed as the filler material of filled thin-walled tubes (FTTs), and a series of experimental study is conducted to investigate the dynamic behavior and energy absorption performance of PM-35 filled thin-walled tubes under impact loading. Firstly, cylinder solid specimens of PM-35 steel are tested to investigate the impact mechanical behavior by using the Split Hopkinson pressure bar set (SHP); Secondly, the filled thin-walled tube specimens with different geometric parameters are designed and tested to investigate the feasibility of PM-35 steel applied in FTTs by the orthogonal test. According to the results of this research, it is concluded that PM-35 steel is with the excellent characteristics of high energy absorption capacity and low yield strength, which make it a potential filler material for FTTs. The micron-sizes pore structure of PM-35 is the main reason for the macroscopic mechanical behavior of PM-35 steel under impact loading, which makes the material to exhibit greater deformation when subjected to external forces and obviously improve the toughness of the material. In addition, PM-35 steel core-filled thin-wall tube has excellent energy absorption ability under high-speed impact, which shows great application potential in the anti-collision structure facilities of high-speed railway and maglev train. The parameter V0 is most sensitive to the energy absorption of FTT specimens under impact loading, and the sensitivity order of different variations to the energy absorption is loading speed V0>D/t>D/L. The loading efficiency of the FTT is affected by its different geometry, which is mainly determined by the sleeve material and the filling material, which are not sensitive to changes in loading speed V0, D/t and D/L parameters.

• 한국정밀공학회지
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• 제21권1호
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• pp.189-196
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• 2004

A modified generalized particle algorithm, MGPA, was suggested to improve the calculation efficiency of standard SPH Method in numerical analysis of high speed impact behavior. MGPA had a new weight function to reduce computation time. The efficiency of this method was proven through calculation for the sample problems of one dimensional rod impact problem and two dimensional plate impact problem. The MGPA method reduced the calculation error and stress oscillation near the boundaries. The validity of this approach was shown by the comparison with ABAQUS results in two dimensional plate impact problem.