• 대한기계학회논문집A
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• 제25권7호
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• pp.1089-1096
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• 2001

This paper presents the fatigue behavior of composite materials with impact-induced damage under 2 level block loading. For this purpose, the 2 level block loading fatigue tests were performed on the impacted composite laminate. The fatigue life of the laminate under the block loading is greatly influenced by the impact damage; the effect of impact damage can be characterized by the present impact damage parameter. Based on this parameter, the model is developed to predict the fatigue life under block loading and the results by this model agree well with experimental results regardless of applied impact energy. Also, stochastic model is established to describe the variation of cumulative damage behavior and fatigue life due to the material nonhomogeneity.

• Structural Engineering and Mechanics
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• 제56권2호
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• pp.157-167
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• 2015

The impact behavior of epoxy-based nanocomposites reinforced with carbon nano tube (CNT), carbon nano fiber (CNF) and mixed contents of these nanoparticles was investigated using Izod impact test. The results showed that while the impact strength of nanocomposites containing 1 wt% of CNT and 1 wt% of CNF increased 19% and 13% respectively, addition of mixed contents of these nanofillers (0.5-0.5 wt%) demonstrated higher improvement (21%) in the impact resistance. The trend of the results is explained on the basis of different fracture mechanisms of nanocomposites. Furthermore, the fracture surface of specimens and the dispersion state of nanoenhancers have been studied using scanning electron microscopy (SEM) photographs.

• Steel and Composite Structures
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• 제48권3호
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• pp.305-320
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• 2023

The mechanical properties of polymeric composites are degraded under elevated temperatures due to the effect of temperature on the mechanical behavior of the resin and resin fiber interfaces. In this study, the effect of temperature on the impact response of the carbon fiber reinforced plastics (CFRP) was investigated at low-velocity impact (LVI) using a drop-weight impact tester machine. All the composite plates were fabricated using a vacuum infusion process with a stacking sequence of [45/0_2/-45/90_2]s, and a thickness of 2.9 mm. A group of the specimens was exposed to an environment with a temperature cycling at the range of -30 ℃ to 65 ℃. In addition, three other groups of the specimens were aged at ambient (28 ℃), -30 ℃, and 65 ℃ for ten days. Then all the conditioned specimens were subjected to LVI at three energy levels of 10, 15, and 20 J. To assess the behavior of the damaged composite plates, the force-time, force-displacement, and energy-time diagrams were analyzed at all temperatures. Finally, radiography, optical microscopy, and scanning electron microscopy (SEM) were used to evaluate the effect of the temperature and damages at various impact levels. Based on the results, different energy levels have a similar effect on the LVI behavior of the samples at various temperatures. Delamination, matrix cracking, and fiber failure were the main damage modes. Compared to the samples tested at room temperature, the reduction of temperature to -30 ℃ enhanced the maximum impact force and flexural stiffness while decreasing the absorbed energy and the failure surface area. The temperature increasing to 65 ℃ increased the maximum impact force and flexural stiffness while decreasing the absorbed energy and the failure surface area. Applying 200 thermal cycles at the range of -30 ℃ to 65 ℃ led to the formation of fine cracks in the matrix while decreasing the absorbed energy. The maximum contact force is recorded under cyclic temperature as 5.95, 6.51 and 7.14 kN, under impact energy of 10, 15 and 20 J, respectively. As well as, the minimum contact force belongs to the room temperature condition and is reported as 3.93, 4.94 and 5.71 kN, under impact energy of 10, 15 and 20 J, respectively.

• 한국콘텐츠학회논문지
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• 제13권2호
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• pp.244-253
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• 2013

본 연구는 공공부문이 능력주의로 변화하는 과정 속에서 공무원들이 인지하는 조직공정성이 조직시민행동에 어떠한 영향력을 미치는가를 실증적으로 분석하는데 있다. 연구결과를 요약하면 다음과 같다. 첫째, 조직공정성 요인과 직무만족의 관계에 있어 절차공정성과 상호작용공정성이 통계적으로 유의한 수준에서 영향관계 있는 것으로 나타났다. 둘째, 조직공정성과 조직시민행동의 관계에 있어 상호작용공정성은 조직시민행동에 밀접한 영향관계가 있는 것으로 나타났다. 셋째, 조직공정성과 조직시민행동의 관계에서 직무만족은 상당한 수준에서 매개변수의 효과를 가지고 있는 것으로 나타났다. 이러한 연구결과는 공무원들의 조직시민행동의 행태를 경험적으로 설명함으로써 조직행태이론의 발전에 기여할 것으로 판단된다.

• Asian Journal of Business Environment
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• 제12권4호
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• pp.1-12
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• 2022

Purpose: This study mainly aims to investigate the connection between job satisfaction and organizational citizenship behavior of bank employee. Another objective of this study is to check out the mediating impact of perceived organizational politics of bank personnel on the connection between their job happiness and citizenship behavior. Research design, data and methodology: Snowball sampling is utilized in this study, which is done among bank personnel at different public and private banks across north-eastern region of Bangladesh as well as information is accumulated through the use of a five-point Likert-scale questionnaire. IBM SPSS v22, Andrew F. Hayes process macro v3.5 and SmartPLS 3 are used to complete descriptive and inferential statistics. Results: The study results explore that employees' political perception has a negative influence on organizational citizenship behavior where bank employees' job happiness has a positive impact on structural citizenship manners and negative impact on perceived organizational politics. Surprisingly, perceptions of organizational politics were found to have an insignificant mediating effect on the connection between job satisfaction and organizational citizenship behavior. Conclusions: The present study reveals that satisfied bank personnel shows positive and constructive actions toward their organization where their political perception has an insignificant mediation.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.423-435
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• 2022

Sharing culture brings many benefits to enterprises, creating initiative and efficiency in the work performance of managers and employees. The study aims to test the correlation between Sharing culture, opportunistic behavior, and effectiveness of employee management in enterprises in Vietnam. There is the implementation of a quantitative research method, through analysis of linear structural model SEM, with survey data including 601 samples of employees at enterprises. Research results show that sharing culture has a direct and negative impact on opportunistic behavior, positively on the effectiveness of employee management in enterprises. In these correlations, the employee's Trust and Organization commitment act as mediators. At the same time, opportunistic behavior has also been shown to play a mediating role in the relationship between the impact of Sharing culture on the effectiveness of employee management. Based on those results, the study suggested several recommendations to improve the effectiveness of employee management. The findings of this study have shown the importance of sharing culture and its direct and indirect correlation with opportunistic behavior and the effectiveness of employee management. These are meaningful contributions in both theory and practice of the research, and they will be the important basis for further research.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2023년도 제68차 하계학술대회논문집 31권2호
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• pp.709-710
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• 2023

Consumer attitudes and behaviors towards brands are not only related to the perception of corporate brand image but also to factors such as the image of the country of origin, the characteristics of the host country, and consumer individual traits. This article focuses on Chinese multinational companies and aims to study the impact of brand international image and country-of-origin brand image on consumer behavior. A model is constructed with brand international image and country-of-origin brand image as antecedent variables, host country characteristics and consumer traits as moderators, and consumer behavior as the outcome. This study employs a questionnaire survey method targeting foreign residents living in China as participants. The research findings reveal that during the internationalization process, both brand international image and country-of-origin brand image have a significant positive impact on consumer behavior, while host country characteristics and consumer traits play a moderating role. The conclusions of this research enrich the theoretical understanding of brand internationalization and explore the influencing factors of consumer behavior, providing a basis for decision-making for multinational company executives.

• 한국콘텐츠학회논문지
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• 제16권10호
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• pp.730-744
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• 2016

본 연구는 팀장의 변혁적 리더십에 영향을 주는 차상위 리더의 윤리적 리더십의 효과를 실증함과 동시에 차상위 리더의 윤리적 리더십과 팀장의 변혁적 리더십이 구성원의 선제적 행동(주도적 행동, 도움행동)에 미치는 영향을 규명하였다. 또한 차상위 리더의 도덕적 행동과 구성원의 선제적 행동의 관계에서 팀장의 변혁적 리더십의 매개역할을 검증하였다. 실증분석 결과, 먼저 차상위 리더의 윤리적 리더십 중 도덕적 행동이 팀장의 변혁적 리더십에 통계적으로 유의미한 긍정적인 영향을 주었다. 그러나 차상위 리더의 행동진실성과 맥락적 일관성은 통계적으로는 유의미하지 않았다. 둘째, 차상위 리더의 도덕적 행동은 구성원의 선제적 행동(주도적 행동, 도움행동)에 긍정적인 영향을 주었다. 또한 차상위 리더의 행동진실성은 구성원의 주도적 행동에만 긍정적인 영향을 주었다. 그러나 차상위 리더의 맥락적 일관성은 구성원의 선제적 행동과 통계적으로 유의미하지 않았다. 셋째, 팀장의 변혁적 리더십은 구성원의 선제적 행동(주도적 행동, 도움행동)에 긍정적인 영향을 주었다. 마지막으로 차상위 리더의 도덕적 행동과 구성원의 선제적 행동(주도적 행동, 도움행동)의 관계에서 팀장의 변혁적 리더십은 부분매개역할을 수행하였다. 그러나 차상위 리더의 행동진실성 및 맥락적 일관성과 구성원의 선제적 행동과는 매개효과가 검증되지 않았다. 마지막으로 토의 및 결론을 통해서 본 연구의 시사점과 한계점 및 향후 연구방향을 제시하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.78-82
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• 2001

Impact behaviors of Aluminum Honeycombs Sandwich Panel(AHSP) by drop weight test were investigated. Two types of specimens with 1/2" and 1/4" cell size were tested by two impactors which are weight of $5.25\textrm{kg}_{\textrm{f}}$ and $11.9\textrm{kg}_{\textrm{f}}$. Parametric studies were achieved including the impactor weight and impact sites which consist face, long-edge, short-edge, and point of the specimen. Face one of impact sites was the strongest and short-edge one of impact sites was the weakest. The damaged area of AHSP was enlarged with the increase of impactor weight that is equal to impact energy. After 3 point bending test, fracture modes of AHSP were analyzed with AE counts. Lower facesheet was fractured in the long-edge direction and then separated between facesheet and core. In the short-edge direction after core wrinkled, lower facesheet tear occurred. Impact behavior by FE analysis were increased localized damage in fast velocity because the faster velocity of the impact was, the smaller the stress of core was. Consequently, impactor weight had an effect on widely damaged area, while the impact velocity was caused on the localized damaged area.aged area.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.101-106
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• 2003

In order to investigate the mechanical behavior of newly developed materials, the evaluation of mechanical properties using small-size specimen is essential. For those purposes, an instrumented impact testing apparatus, which provides the load-displacement curve under impact loading without oscillations, was devised. To develop the test procedure with the setup, the impact behaviors of various kinds of structural materials such as S45C, SCM4, Ti alloys (Ti-6V-4Al) and Zr-based bulk amorphous metal, were investigated through the instrumented Charpy V-notch impact tests. The calibrations of the dynamic load and displacement that was calculated based on the Newton' second law were carried out through the quasi-static load test and the comparison of a directly measured value using a laser displacement meter. Satisfactory results could be obtained. The crack initiation and propagation processes during impact fracture could be well divided on the curve, depending on the intrinsic characteristic of specimen tested; ductile or brittle. The absorbed impact energy in Zr-basd BAM was largely used for crack initiation not for crack propagation process. The fracture surfaces under impact loading showed different feature when compared with the static cases.