• Title/Summary/Keyword: Overload effect

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Analysis on Short Crack Growth Rate after Single Overload under Cyclic Bending Moment

  • Song, Sam-Hong;Lee, Kyeong-Ro;Kim, Amkee
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.3
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    • pp.19-26
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    • 2001
  • In order to investigate the effect of single tensile overload on the short crack growth behavior under the out-of-plane cyclic bending moment, crack opening stresses were continuously measured by an elastic compliance method using strain gages. The characteristics of short crack growth after the single tensile overload are analyzed by the effective stress range ratio. Futhermore, the investigation was carried out with respect to various fatigue crack growth behaviors such as the plastic zone size effect on crack retardation, the retarded crack length and the number of cycles.

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An Exploratory Research on Causality among Information Technology Stress Creators in Organizations (조직 내 정보 기술 스트레스 유발요인들 간의 인과관계에 대한 탐색적 연구)

  • Yim, Myung-Seong
    • Journal of Digital Convergence
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    • v.10 no.8
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    • pp.1-14
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    • 2012
  • The purpose of this study is to explore the causality among technostress creators. In doing so, we can suggest the ways how to reduce a technostress of employees. Research results suggest that pace of change has a positive effect on the work overload and has a negative effect on work-home conflict. Complexity of technology positively influences not only work overload but job insecurity. Work overload has a significant effect on work-home conflict. Finally, work-home conflict has a positive effect on job insecurity. Conclusions and implications are discussed.

Who Can be the Target of SNS Review Marketing? : A Study on the SNS Based Marketing Strategy (SNS 구매후기는 누구의 마음을 움직이는가? : 소셜 네트워크 서비스를 활용한 마케팅 전략 연구)

  • Shim, Seonyoung
    • Journal of Information Technology Services
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    • v.11 no.3
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    • pp.103-127
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    • 2012
  • With the advent of SNS (Social Network Services), the product reviews by friends in SNS are intensively utilized for online marketing. However, there is a lack of empirical evidence on the actual marketing effect of SNS reviews, although we need to identify who can be the target of SNS marketing in terms of customer attributes, preferences, or experiences. In this study, we investigate the moderating role of customer attributes in identifying the effect of SNS reviews on customer purchasing decision. As the moderating variables, we adopt 'information search experience' and 'perception of information overload'. Research results evidence that, in order to understand the effect of SNS reviews in a comprehensive manner, we need to examine it in the context of various related factors such as 'information search experience' and 'perception of information overload'. The results show that the persuading effect of SNS reviews for product purchasing is stronger for the customers with the lower information search experiences as well as the lower perception on the information overload on the web. This result delivers managerial implications on who can be the target customers of SNS marketing.

The Influence of Mobile Office Systems on Users' Job Stress and Work Overload (모바일 오피스 시스템이 사용자의 업무과부하 및 직무 스트레스에 미치는 영향)

  • Yun, Hae-Jung;Choi, Gui-Young;Lee, Choong-C.
    • The Journal of Information Systems
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    • v.20 no.2
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    • pp.155-176
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    • 2011
  • The use of mobile office systems has been expanded due to the smartphones' rapid diffusion in Korea, and it has brought a new work environment that is different from traditional working patterns. In this study, the unique attributes of mobile office systems, such as ubiquity, usefulness, complexity, and insecurity, are examined along with the impact of these attributes on work overload and job stress. Based on transaction-based model of job stress, organizational support was applied as a stress inhibitor and also the moderator between work overload and job stress. The findings of this study show that ubiquity increases usefulness of mobile office systems; complexity increases both work overload and job stress; and insecurity increases job stress. Surprisingly, usefulness increases job stress, which means employees who perceive the efficiency of mobile office systems higher may feel more job stress. Organizational support for mobile office systems significantly shows the moderating effect, but no direct mitigating effect on job stress. The theoretical and practical implications in order to mitigate the side effects of mobile office systems based on the research findings are thoroughly discussed.

Fracture Mechanic's Approach on Retardation Behaviors under Overloading (과대 하중작용 시 균열성장 지연 거동에 대한 파괴역학적 정리)

  • Kang, Yong-Goo;Park, Jun-Young
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.5
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    • pp.13-20
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    • 2012
  • In order to clarify the effect of overload on crack growth behaviors, fatigue tests for overload were carried out for round plain specimens of SM45C steel. In the experiment, typical semi-elliptical crack shape was found and further crack growth behaviors were tested. Using three types of single overload fatigue tests, Crack growth retardation phenomenon were examined. The growth rate of surface crack(da/dN) during retardation period was analyzed in terms of ${\Delta}K$ and ${\Delta}K_{eff}$. On the growth rate of surface crack analyzed by ${\Delta}K$, the dependence of overload stress levels appears. However, on the growth rate by ${\Delta}K_{eff}$ obtained by Willenborg analysis, there is a non-liner relationship between da/dN and ${\Delta}K_{eff}$ with narrow scatter band.

Fracture Mechanic's Approach on Retardation Behaviors under Overloading (과대하중작용 시 균열성장 지연거동에 대한 파괴역학적 정리)

  • Kang, Yong-Goo;Park, Jun-Young
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.4
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    • pp.82-89
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    • 2012
  • In order to clarify the effect of overload on crack growth behaviors, fatigue tests for overload were carried out for round plain specimens of SM45C steel. In the experiment, typical semi-elliptical crack shape was found and further crack growth behaviors were tested. Using three types of single overload fatigue tests, Crack growth retardation phenomenon were examined. The growth rate of surface crack(da/dN) during retardation period was analyzed in terms of ${\Delta}K$ and ${\Delta}K_{eff}$. On the growth rate of surface crack analyzed by ${\Delta}K$, the dependence of overload stress levels appears. However, on the growth rate by ${\Delta}K_{eff}$ obtained by Willenborg analysis, there is a liner relationship between da/dN and ${\Delta}K_{eff}$ with narrow scatter band.

Effect of Anisotropy on Fatigue Crack Propagation Rate and Arrest Behavior with 2024-T3 Alumunum Alloy (2024-T3 A1 합금의 이방성이 피로균열진전속도와 정류거동에 미치는 영향)

  • 오세욱;김태형;오정종
    • Journal of Ocean Engineering and Technology
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    • v.7 no.1
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    • pp.124-132
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    • 1993
  • In order to examine the effect of anisotropy and stress ratio on fatigue crack propagation rate and opening-closing behavior and also arrest behavior by single tension peak overload, the fatigue tests of constant amplitude atress and single tension peak overload adding to cycle of constant amplitude were carried out in stress ratio of -0.4, -0.2, and 0.4 with materials of T-L and L-T directions in 2024-T3 aluminum alloy plate. Crack opening-closing begavior were measured by the compliance method using COD gage and strain gage. In case of the crack opening-closing behavior was measured by strain gage, the effect of stress ratio is unchangeable. But in the case of COD gage, that is remarkably decreased. Fictitious effective stress intensity factor(U sub(f)) and effective stress intensity factor ratio(U) in L-T direction was higher than those in T-L direction and also threshold arrest overload ratio incrased as stress ratio decreased and that of T-L direction was higher than that in L-T direction.

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ANALYSIS OF A QUEUEING SYSTEM WITH OVERLOAD CONTROL BY ARRIVAL RATES

  • CHOI DOO IL
    • Journal of applied mathematics & informatics
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    • v.18 no.1_2
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    • pp.455-464
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    • 2005
  • In this paper, we analyze a queueing system with overload control by arrival rates. This paper is motivated by overload control to prevent congestion in telecommunication networks. The arrivals occur dependent upon queue length. In other words, if the queue length increases, the arrivals may be reduced. By considering the burstiness of traffics in telecommunication networks, we assume the arrival to be a Markov-modulated Poisson process. The analysis by the embedded Markov chain method gives to us the performance measures such as loss and delay. The effect of performance measures on system parameters also is given throughout the numerical examples.

Positive Psychological Capital and Turnover Intention: The Mediating Effect of Perceived Work Overload and the Moderating Effect of Trust in Supervisor (긍정심리자본이 이직의도에 미치는 영향: 인지된 직무과부하의 매개효과와 상사신뢰의 조절효과)

  • Choi, Kwang Woo;Rhee, Seung-Yoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.382-392
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    • 2017
  • This study analyzed the effect of an employee's psychological capacity(positive psychological capital), on perceived work overload, and explored how trust in supervisor moderated this relationship. In addition, we examined how positive psychological capital and perceived work overload influenced turnover intention. In doing so, we identified the antecedents of perceived work overload, and suggested ways to nurture positive psychological capital in organizations. Using survey data from 214 employees in the manufacturing industry in Korea, we found that positive psychological capital was negatively related to perceived work overload, and that the relationship was moderated by trust in supervisors. In addition, positive psychological capital was negatively associated while perceived work overload was positively associated with turnover intention. Results suggest the importance of understanding positive psychological capital given its crucial relationship with perceived work overload and turnover intention. The result also emphasizes the role that trust in supervisor plays, and the need to nurture employees' positive psychological capital in organizations.

The Effect of Stress Ratio on Fatigue Crack Propagation Rate and Arrest Behavior in 7075-T735 Al Alloy (7075-T735 Al 합금의 피로균열 진전속도와 정류거동에 미치는 응력비의 영향)

  • 오세욱;강상훈;허정원;김태형
    • Journal of Ocean Engineering and Technology
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    • v.6 no.1
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    • pp.131-139
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    • 1992
  • The understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading is very important for life prediction of the air travel structures. Particularly, the retardation and arrest behavior of fatigue crack propagation by single tension overloading is essential to the understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading. Numerous studies of the retardation behavior have been performed, however investigations of the arrest behavior have not been enough yet. As for the arrest behavior, Willenborg had reported that the overload shut-off ratio $[R_{so}=(K_{OL})/K_{max})_{crack arrest}]$ had been the material constant, but recently several investigators have reported that the overload shut-off ratio depends upon the stress ratio. In this study, authors have investigated the effect of stress ratio on the threshold overload shut-off ratio to generate arrest of fatigue crack growth in high tensile aluminum alloy 7075-T735 which have used in material for air travel structures, It has been $-0.4\leqqR\leqq0.4$ till now, the region of stress ratio investigated. The threshold overload shut-off ratio has decreased as stress ratio has increased in overall region of -$-0.4\leqqR\leqq0.4$ and the linearity has been seen in this material. Moreover, the experimental equation between $R_{so}$ and R has been made; The relation has been $R_{so}=-R+2.6$.

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