• Title/Summary/Keyword: ties

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Compressive behavior of steel stirrups-confined square Engineered Cementitious Composite (ECC) columns

  • Zheng, Pan-deng;Guo, Zi-xiong;Hou, Wei;Lin, Guan
    • 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.

Social Support in the Times of Social Distancing: Learnings from the South Asian Context

  • BASHIR, Mohsin;SALEEM, Ammara;ALI, Qamar
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.3
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    • pp.65-76
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    • 2022
  • This study will examine the relationship between social support from the work and family domains, referred to as multiple social network ties (MSNT), and employees' job and family-related performance outcomes during the COVID-19 crisis. The study also demonstrates the importance of employees' work-family balance (WFB) in moderating the association between MSNT and job and family-related performance. A two-wave design was used to collect data from 320 managerial level personnel in Pakistan's textile sector. The path analysis technique of structural equation modelling (SEM) was used to analyze the responses. In times of crisis, social support mechanisms could potentially replace organizational support mechanisms for employees dealing with work and family obligations, according to the study. The findings of this study show that work-family balance is a significant partial mediator between MSNT and employees' job and family-related outcomes during the COVID-19 pandemic, according to a best-fit model. This research supports the pragmatic view of MSNT's action mechanism in generating jobs for employees and family-related results, especially in uncertain situations. According to the findings, employees who have a positive work-life balance are happier and more productive in both work and personal life. It has major implications for human resource management (HRM) research and practice.

Axial strength of FRP-reinforced geopolymeric concrete members: A step towards sustainable construction

  • Mohamed Hechmi El Ouni;Ali Raza;Bisma Khalid;Afzal Ahmed;Muhammad Sohail Jameel;Yasser Alashker
    • Structural Engineering and Mechanics
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    • v.86 no.5
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    • pp.687-704
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    • 2023
  • This study aims to examine the structural response of glass fibre-reinforced polymer (Glass-FRP) reinforced geopolymer electronic waste aggregate concrete (GEWC) compression elements under axial compression for sustainable development. The research includes the fabrication of nine GEWC circular compression elements with different reinforcement ratios and a 3-D nonlinear finite element model using ABAQUS. The study involves a detailed parametric analysis to examine the impact of various parameters on the behavior of GEWC compression elements. The results indicate that reducing the vertical distance of glass-FRP ties improves the ductility of GEWC compression elements, and those with eight longitudinal rebars have higher axial load-carrying capacities. The finite element predictions were in good agreement with the testing results, and the put forwarded empirical model shows higher accuracy than previous models by involving the confinement effect of lateral glass-FRP ties on the axial strength of GEWC compression elements. This research work contributes to minimizing the carbon footprint of cement manufacturing and electronic waste materials for sustainable development.

Multi-level Analysis of the Antecedents of Knowledge Transfer: Integration of Social Capital Theory and Social Network Theory (지식이전 선행요인에 관한 다차원 분석: 사회적 자본 이론과 사회연결망 이론의 결합)

  • Kang, Minhyung;Hau, Yong Sauk
    • Asia pacific journal of information systems
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    • v.22 no.3
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    • pp.75-97
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    • 2012
  • Knowledge residing in the heads of employees has always been regarded as one of the most critical resources within a firm. However, many tries to facilitate knowledge transfer among employees has been unsuccessful because of the motivational and cognitive problems between the knowledge source and the recipient. Social capital, which is defined as "the sum of the actual and potential resources embedded within, available through, derived from the network of relationships possessed by an individual or social unit [Nahapiet and Ghoshal, 1998]," is suggested to resolve these motivational and cognitive problems of knowledge transfer. In Social capital theory, there are two research streams. One insists that social capital strengthens group solidarity and brings up cooperative behaviors among group members, such as voluntary help to colleagues. Therefore, social capital can motivate an expert to transfer his/her knowledge to a colleague in need without any direct reward. The other stream insists that social capital provides an access to various resources that the owner of social capital doesn't possess directly. In knowledge transfer context, an employee with social capital can access and learn much knowledge from his/her colleagues. Therefore, social capital provides benefits to both the knowledge source and the recipient in different ways. However, prior research on knowledge transfer and social capital is mostly limited to either of the research stream of social capital and covered only the knowledge source's or the knowledge recipient's perspective. Social network theory which focuses on the structural dimension of social capital provides clear explanation about the in-depth mechanisms of social capital's two different benefits. 'Strong tie' builds up identification, trust, and emotional attachment between the knowledge source and the recipient; therefore, it motivates the knowledge source to transfer his/her knowledge to the recipient. On the other hand, 'weak tie' easily expands to 'diverse' knowledge sources because it does not take much effort to manage. Therefore, the real value of 'weak tie' comes from the 'diverse network structure,' not the 'weak tie' itself. It implies that the two different perspectives on strength of ties can co-exist. For example, an extroverted employee can manage many 'strong' ties with 'various' colleagues. In this regards, the individual-level structure of one's relationships as well as the dyadic-level relationship should be considered together to provide a holistic view of social capital. In addition, interaction effect between individual-level characteristics and dyadic-level characteristics can be examined, too. Based on these arguments, this study has following research questions. (1) How does the social capital of the knowledge source and the recipient influence knowledge transfer respectively? (2) How does the strength of ties between the knowledge source and the recipient influence knowledge transfer? (3) How does the social capital of the knowledge source and the recipient influence the effect of the strength of ties between the knowledge source and the recipient on knowledge transfer? Based on Social capital theory and Social network theory, a multi-level research model is developed to consider both the individual-level social capital of the knowledge source and the recipient and the dyadic-level strength of relationship between the knowledge source and the recipient. 'Cross-classified random effect model,' one of the multi-level analysis methods, is adopted to analyze the survey responses from 337 R&D employees. The results of analysis provide several findings. First, among three dimensions of the knowledge source's social capital, network centrality (i.e., structural dimension) shows the significant direct effect on knowledge transfer. On the other hand, the knowledge recipient's network centrality is not influential. Instead, it strengthens the influence of the strength of ties between the knowledge source and the recipient on knowledge transfer. It means that the knowledge source's network centrality does not directly increase knowledge transfer. Instead, by providing access to various knowledge sources, the network centrality provides only the context where the strong tie between the knowledge source and the recipient leads to effective knowledge transfer. In short, network centrality has indirect effect on knowledge transfer from the knowledge recipient's perspective, while it has direct effect from the knowledge source's perspective. This is the most important contribution of this research. In addition, contrary to the research hypothesis, company tenure of the knowledge recipient negatively influences knowledge transfer. It means that experienced employees do not look for new knowledge and stick to their own knowledge. This is also an interesting result. One of the possible reasons is the hierarchical culture of Korea, such as a fear of losing face in front of subordinates. In a research methodology perspective, multi-level analysis adopted in this study seems to be very promising in management research area which has a multi-level data structure, such as employee-team-department-company. In addition, social network analysis is also a promising research approach with an exploding availability of online social network data.

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Family Ties between Aging Parents and Adult Children Living in Separate Households: Social Support from a Social Exchange Perspective (노부모와 별거 성인자녀와의 가족유대: 정서적 지원에 대한 교환이론적 접근)

  • 정기원
    • Korea journal of population studies
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    • v.24 no.1
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    • pp.123-148
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    • 2001
  • This study explores the factors affecting emotional support between aging parents and adult children living in separate households. With a social exchange perspective on intergenerational family relationship as theoretical framework, the effects of aging parents\` demographic characteristics, potential reward resources. and need for care were tested by analyzing data collected from 2.535 persons aged 65 and over in 9,355 sample households of \`National Survey of Living Status and Welfare Needs of the Elders-1998\`. The statistical analysis of 2,205 aging parents with adult children living in seperate households reveals that the aging parents who have potential reward resources are provided more emotional support by their children than the aging parents without resources are. Findings also show that the elders who live in same households with their own children, and need help from other people with instrumental activities of daily living obtain less emotional support from their children living in separate households. The empirical findings of this study support the social exchange perspectives on family ties between aging parents and adult children living in separate households. but only 8.9 per cents of variance in degree of emotional support is explained by the variables included in the model.

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A Study on How Social Comparison Between Players on Mobile Puzzle SNG When Competeing on leaderboard, Affect the Competition and Chllenge - Focused on Self-Evaluation maintenance model - (모바일 퍼즐 SNG 순위경쟁상황에서 플레이어의 사회비교가 경쟁심과 도전감에 미치는 영향 - 자기평가유지모형을 중심으로 -)

  • Kim, Jaehyun;Choi, Chris Seoyun;Kim, Hyunsuk
    • Journal of the HCI Society of Korea
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    • v.13 no.3
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    • pp.5-15
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    • 2018
  • The biggest characteristic of Social Network Game(SNG) is that games are played through competition and cooperation with the actual acquaintances based on SNS. Even though such competition and challenge spirit have been dealt importantly as preceding factors having influence on the flow in games in the existing game area, it is rare to find researches deeply considering the characteristics of ranking competition between acquaintances in SNG. Moreover, it was not considered that such acquaintances could be the targets of competition and also challenge at the same time in SNG. Therefore, this study examined the achievements(big differences in ranking, small differences in ranking) of the targets for comparison and closeness(strong ties, weak ties) with the targets for comparison as factors having influence on competition and challenge spirit, and also empirically analyzed the influence of such factors and interactions between factors on players' competition and challenge spirit in the ranking competitive society, by analyzing the characteristics of ranking competition between acquaintances in the mobile puzzle, SNG based on SNS through the analysis on the preceding research on the self-evaluation maintenance model of the social comparison theory. In the results, when preferentially exposing competitors with small difference in ranking and also exposing competitors with stronger ties, players' competition is stimulated, so that it can improve their challenge spirit. Such results of this study can be expected to a lot contribute to the actual design work of SNG ranking table contents.

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Evaluation of Axial Behavior of Columns Strengthened with Different Transverse Reinforcements in Jacket Section (확대단면에서의 띠철근 배근 방법에 따른 보강 기둥의 중심 축하중 거동 평가)

  • Hwang, Yong-Ha;Yang, Keun-Hyeok;Sim, Jae-Il;Choi, Yong-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.81-88
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    • 2018
  • The present study evaluated the effective arrangement approach of transverse reinforcement in the jacket section for seismic strengthening of reinforced concrete columns. To simulate the full-scale columns, the section dimensions were determined as $450{\times}450mm$ for non-seismic existing columns and $750{\times}750mm$ for section enlargement strengthening columns. Over-lapped channel-shape bars and prefabricated bar units were proposed for closed-hoops in the jacket section, and conventional cross-ties anchored into existing columns and V-ties were considered for the supplementary ties. Test results showed that the axial capacity of the existing column and section enlargement columns with over-lapped channel-shape hoops was similar to the nominal strength calculated using ACI 318-14 procedure whereas the section enlargement column with prefabricated bar units possessed 1.25 times higher axial capacity than the nominal prediction. Furthermore, the axial ductility ratio of the section enlargement column with prefabricated bar unit was 139% higher than that of the existing column despite the potential size effect on ductility of concrete. Thus, it can be concluded that the developed prefabricated bar unit technique is practically useful for preventing the premature buckling of longitudinal reinforcement and confining core concrete in the section enlargement strengthening columns.

A Study of Social Network Type among Korean Older Persons: Focusing on Network Size, Frequencies of Contact, and Closeness (한국 노인의 사회적 연계망 유형: 연계망 크기, 접촉 빈도, 친밀도를 중심으로)

  • Chung, Kyunghee;Kang, Eun Na
    • 한국노년학
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    • v.36 no.3
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    • pp.765-783
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    • 2016
  • This study examines 2014 National Survey on Older Koreans (10,279 persons aged 65 or above) to understand social networks among older Koreans. In order to classify the types of social relationships, the latent profile analysis is conducted based on such structural aspects of social networks as network size, frequencies of contact, and closeness. The results show that older Koreans can be categorized into 5 distinct social network types: disengaged (11.6%), ritual-family-focused (17.7%), close-family-focused (23.6%), close-restricted (28,4%), and diverse (18.8%). Characteristics by each social network type are compared and multinominal logistic regression analyses are applied to figure out the influencing factors of social network type. Older persons with disengaged social network ties tend to be overwhelmingly female, living alone, old-old, and of low socioeconomic status. On the other hand, older persons with diverse social network ties tend to be young-old and had highly-ranked jobs in their mid-life. Spouse/children are the focal point of social relationships in both ritual-family-focused and close-restricted social network. However, the proportion of men is higher in the close-family-focused type than in the ritual-family-focused. Older Koreans with close-restricted social network ties tend to be female, uneducated, and have engaged in agricultural and allied activities. This study discusses the implications of its findings and how research in this area should develop in the future.

A Study on the Mediating Effect of Perceived Customer Value onthe Relationship Between Relationship Marketing Factors and Loyalty on Rural Tourism (농촌관광의 관계마케팅 활동요인과 충성도 간의 관계에서 고객지각가치의 매개효과에 관한 연구)

  • Lee, Joo-Heon;Hwang, Tae Hee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.2
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    • pp.179-193
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    • 2022
  • This study aims to identify the relationship marketing factors and examine the mediating factors of perceived customer value on the relationship between relationship marketing factors and loyal on rural tourism. We collected and analyzed the survey data from the customers who had experienced rural tourism before. The results from the empirical analysis are as follows. First, through the exploratory factor analysis, four factors such as customer orientation, responsive attraction, professionalism, and ties were derived. Second, it was found all four factors have significant positive effects on loyalty. Third, both responsive attraction and professionalism have significant positive effects on perceived customer value. However, customer orientation and ties do not have significant effects. Fourth, the perceived customer value showed a full mediating effect between responsive attraction and loyalty, whereas it showed a partial mediating effect between professionalism and loyalty. Additionally, it was found that gender did not affect loyalty but significantly affected perceived customer value. This means that women had lower perceived value for rural tourism than men. To improve the loyalty of rural tourism, it is necessary to improve customer orientation, professionalism, ties, and perceived customer value.