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Earthquake Response Analysis of a RC Bridge Including the Effect of Repair/retrofitting (보수/보강 효과를 고려한 철근콘크리트교량의 내진응답해석)

  • Lee, Do Hyung;Cho, Kyu Sang;Jeon, Jeong Moon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.4A
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    • pp.611-622
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    • 2008
  • Nonlinear analyses have been carried out for both bridge piers and a bridge structure being repaired using a repair element in order to assess the post-repair seismic response of such structures. For this purpose, a simplified CFRP stress-strain model has been proposed. The analytical predictions incorporating the current developments correlate reasonably well with experimental results in terms of strength and stiffness. In addition, nonlinear dynamaic analyses have also been conducted for a bridge structure in terms of the created multiple earthquake sets to evaluate the effect of pier repair on the response of a whole bridge structure. In these analyses, potential plastic hinge zones of piers are virtually repaired by CFRP and steel jacketing. Comparative results prove the virtual necessity of performing nonlinear post-repair analyses under multiple earthquakes, particularly when the post-repair response features are required. In all, the present approaches are expected to provide salient information regarding a healthy seismic repair intervention of a damaged strcuture.

Seismic Performance Evaluation of RC Bridge Piers Using Time-dependent Element (시간종속 요소를 이용한 철근콘크리트교량 교각의 내진 성능 평가)

  • Lee, Do Hyung;Jeon, Jeong-Moon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1A
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    • pp.237-246
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    • 2006
  • In order to evaluate the seismic performance of damaged reinforced concrete members, particularly bridge piers, an inelastic time-dependent element is proposed. The proposed element enables increased characteristics due to structural intervention(i.e., repair or retrofitting) to be accurately reflected to the degraded strength and stiffness of the members. The inelastic time-dependent element having both birth and death time can freely be activated within the user-defined time intervals during static and dynamic time-history analysis. Comparative studies are carried out for reinforced concrete bridge piers that are repaired and retrofitted. Analytical predictions using the developed element show reasonable correlation with experimental results. Also conducted is a nonlinear time-history analysis of a reinforced concrete bridge under multiple earthquakes. The comparative analytical results prove the validation of current development. In all, it is concluded that the present element is capable of providing salient features for the healthy evaluation of seismic performance and hence seismic stability assessment of RC bridge piers being repaired and retrofitted.

Quasi-brittle and Brittle Fracture Simulation Using Phase-field Method based on Cell-based Smoothed Finite Element Method (셀기반 평활화 유한요소법에 기반한 위상분야법을 이용한 준취성 및 취성 파괴 시뮬레이션)

  • Changkye Lee;Sundararajan Natarajan;Jurng-Jae Yee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.5
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    • pp.295-305
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    • 2023
  • This study introduces a smoothed finite-element implementation into the phase-field framework. In recent years, the phase-field method has recieved considerable attention in crack initiation and propagation since the method needs no further treatment to express the crack growth path. In the phase-field method, high strain-energy accuracy is needed to capture the complex crack growth path; thus, it is obtained in the framework of the smoothed finite-element method. The salient feature of the smoothed finite-element method is that the finite element cells are divided into sub-cells and each sub-cell is rebuilt as a smoothing domain where smoothed strain energy is calculated. An adaptive quadtree refinement is also employed in the present framework to avoid the computational burden. Numerical experiments are performed to investigate the performance of the proposed approach, compared with that of the finite-element method and the reference solutions.

Advantages and disadvantages of renewable energy-oil-environmental pollution-from the point of view of nanoscience

  • Shunzheng Jia;Xiuhong Niu;Fangting Jia;Tayebeh Mahmoudi
    • Advances in concrete construction
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    • v.16 no.1
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    • pp.69-78
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    • 2023
  • This investigation delves into the adverse repercussions stemming from the impact of arsenic on steel pipes concealed within soil designated for rice cultivation. Simultaneously, the study aims to ascertain effective techniques for detecting arsenic in the soil and to provide strategies for mitigating the corrosion of steel pipes. The realm of nanotechnology presents promising avenues for addressing the intricate intersection of renewable energy, oil, and environmental pollution from a novel perspective. Nanostructured materials, characterized by distinct chemical and physical attributes, unveil novel pathways for pioneering materials that exert a substantial impact across diverse realms of food production, storage, packaging, and quality control. Within the scope of the food industry, the scope of nanotechnology encompasses processes, storage methodologies, packaging paradigms, and safeguards to ensure the safety of consumables. Of particular note, silver nanoparticles, in addition to their commendable antibacterial efficacy, boast anti-fungal and anti-inflammatory prowess, environmental compatibility, minimal irritability and allergenicity, resilience to microbial antagonism, thermal stability, and robustness. Confronting the pressing issue of arsenic contamination within both environmental settings and the food supply is of paramount importance to preserve public health and ecological equilibrium. In response, this study introduces detection kits predicated upon silver nanoparticles, providing an expeditious and economically feasible avenue for identifying arsenic concentrations ranging from 0.5 to 3 ppm within rice. Subsequent quantification employs Hydride Atomic Absorption Spectroscopy (HG-AAS), which features a detection threshold of 0.05 ㎍/l. A salient advantage inherent in the HG-AAS methodology lies in its capacity to segregate analytes from the sample matrix, thereby significantly reducing instances of spectral interference. Importantly, the presence of arsenic in the soil beneath rice cultivation establishes a causative link to steel pipe corrosion, with potential consequences extending to food contamination-an intricate facet embedded within the broader tapestry of renewable energy, oil, and environmental pollution.

Exploration of the Importance and Impact of Cost Items in Occupational Safety and Health Management Funds and Safety Management Expenditures in Construction (건설업 산업안전보건관리비와 안전관리비의 항목별 중요도 및 영향도 분석)

  • Lee, Jae-Hyun;Jeong, Jae-Wook
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.5
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    • pp.639-650
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    • 2023
  • In this research endeavor, we engaged with 70 construction safety specialists from established construction firms through surveys and interviews. The primary aim was to dissect and understand the weight and ramifications of specific cost items within the Occupational Safety and Health Management Funds(OSHMF) and Safety Management Expenses(SME). From our analysis, salient insights emerged. Within the realm of OSHMF, the cost items associated with safety facilities and the remunerations of safety managers were identified as paramount. It was observed that there are marked variations in the perceived significance and repercussions associated with diverse cost items of OSHMF. In stark contrast, when assessing the SME, the nuances in perceived weight and consequences of individual cost items were relatively muted, suggesting a more uniform viewpoint among the experts. Furthermore, our research probed the interrelationship between the significance and repercussions within OSHMF and SME domains. Notably, OSHMF manifested a positive linear relationship, suggesting that cost items of higher importance invariably had a more pronounced effect. On the other hand, the SME showcased a more subtle association, hinting at intricate underlying dynamics. The outcomes of this investigation are poised to offer instrumental guidance for enhancing safety protocols and diminishing accident occurrences in domestic construction undertakings.

Factors Influencing User Satisfaction with University Library Websites in Myanmar

  • Thet Mon Swe;Siluo Yang
    • Journal of Information Science Theory and Practice
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    • v.12 no.2
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    • pp.1-21
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    • 2024
  • This study aims to develop a comprehensive technological framework anchored in a theoretical model to assess user satisfaction with university library websites (ULWs) in Myanmar. Adopting a quantitative approach, data were obtained via convenience sampling and subsequent inferential analysis. The target population for this study investigated users of various ULWs in Myanmar who were utilizing six university libraries. Of the collected responses, 273 valid surveys were analyzed using SPSS (version 25) and AMOS. Tools such as structural equation modeling and confirmatory factor analysis played pivotal roles in data interpretation and hypothesis validation. The proposed model highlights the significance of information quality, system quality, and librarian services in influencing both perceived usefulness (PU) and perceived ease of use (PEOU), culminating in user satisfaction. Notably, information quality and librarian services primarily impact PU, while system quality is more influential on PEOU. Interestingly, while PU has a direct bearing on user satisfaction, PEOU does not. Moreover, demographic elements such as age, gender, and education level introduce considerable differences in the utilization of ULW services. Drawing from the study's findings, recommendations are made for ULW managers in Myanmar to bolster services, aligning with user preferences. The resulting framework offers tangible benefits to Myanmar's educational sector, including academia, government entities, librarians, and policy framers. This pioneering research delves into the realm of ULWs in Myanmar's higher education sector. Practically, the research underscores the necessity for stakeholders, encompassing Myanmar's library experts and governing bodies, to elevate the standard of ULWs. Theoretically, a salient takeaway is the direct linkage between heightened usefulness and increased user satisfaction.

A study on the factors associated with treatment compliance in adolescent orthodontic patients (청소년기 교정환자의 치료 협조도와 연관된 요소에 관한 연구)

  • Kim, Jin-Ee;Cha, Bong-Kuen;Lee, Nam-Ki
    • The korean journal of orthodontics
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    • v.34 no.2 s.103
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    • pp.177-188
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    • 2004
  • This study is aimed at providing the variables associated with adolescent compliance In orthodontic treatment, and identifies the salient predictors of cooperative behaviors over the course of treatment. Orthodontic attitude scale, orthodontic locus of control scale and demographics data were obtained for 60 adolescent orthodontic patients who had been in treatment a minimum of 10 months. This data was then analyzed in relation to their sex, school age and treatment compliance. The following results were obtained. 1. The scoring of external-powerful others-parents, subscale of the Orthodontic Locus of Control scale, found a statistically significant difference between sex differences (p<0.05). The score of boys was higher than that of girls. 2. The external-powerful others-parents score from the Orthodontic Locus of Control scale showed a significantly positive correlation (p<0.05) with the level of compliance. 3. The salient factors associated with compliance were the adolescent patients' own cognition and decisions. 4. There was a statistically significant correlation between the length of treatment and patient compliance (p<0.05). Thus, there was a substantial decrease in the cooperation of orthodontic patients over time. 5. Other independent variables including age, sex, family environment, religion, academic standing, parents' occupation and education, and brushing frequency were investigated and did not yield any significant relationships. Patient compliance is a critical factor in the efficacy of orthodontic treatment. Individuals vary greatly in their perceptions and attitudes of orthodontic treatment, sociodemographic environments and personality characteristics. In assessing the level of compliance attainable by each individual patient it is advisable To pay sufficient attention not only to the technical matters but also to the psychologic aspects of the treatment progress.

Effects of ad endorser's gaze directions on social perceptions and advertising effectiveness (광고 모델의 시선 효과: 모델의 사회적 특성 지각과 광고 효과성)

  • Kang, Jungsuk
    • Science of Emotion and Sensibility
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    • v.18 no.1
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    • pp.3-14
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    • 2015
  • An ad endorser's gaze direction is a salient nonverbal cue that consumers use in responding to advertisements. The gaze direction influences consumers' social perceptions (e.g., attractiveness, credibility) of the endorser and advertising effectiveness (e.g., advertising attitudes, brand attitudes). Especially, the cerebral emotional asymmetry hypothesis suggests that an ad endorser's left-averted gaze can produce more positive social perceptions and advertising effectiveness than the right-averted gaze for right-handed consumers. This study examined the effects of three gaze directions (direct, left-averted and right-averted gaze directions) of unknown female ad endorser on Korean males' advertising responses (attractiveness-, credibility- and ad-effectiveness-related responses), using online experimental method. The results indicated that the ad endorser's direct gaze was more likely to increase both positive (correspondence bias) and negative (suspicion, deceptiveness) social perceptions of her than the right-averted gaze. The direct gaze also created more positive advertising effectiveness (advertising attitudes) than the right-averted gaze. However, the study failed to find consistent differences in responses between left-averted gaze and either direct or right-averted gaze.

An Empirical Study on the Relationship between Role Stress and Personal Creativity: The Mediating Roles of Creative Self-Efficacy and Personal Initiative (역할스트레스와 개인 창의성 간의 관계에 대한 실증연구: 창의적 자아효능감과 자기주도성의 매개역할)

  • Heo, Myung Sook;Cheon, Myun Joong
    • The Journal of Information Systems
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    • v.22 no.2
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    • pp.51-83
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    • 2013
  • Personal creativity is critically important for organizations seeking to survive and thrive in today's highly turbulent business environments. Organizations must effectively identify and mobilize the creative resources of their members. When organizational members perceive a work environment that restricts or fails to encourage individual creative expression, a gap may exist between the level of individual creative potential and the actual amount of individual creativity practiced within the organization. In this situation, this paper will examine the impact of role conflict, role ambiguity, creative self-efficacy, and personal initiative on personal creativity. Creative self-efficacy is the subjective belief in one's personal ability to be creative, that is, a personal assessment of one's own creative potential. A strong internal belief in one's ability to successfully engage in creative behaviors is generally considered an important part of the creative process. Personal Initiative refers to behaviors, mainly directed toward work and organizational issues, that are characterized by the following aspects: self-starting, proactive, and persistent in overcoming barriers. Creativity-related creative self-efficacy and personal initiative are critical components to understand motivation that coordinates the relationship between perception and behavior of individual employees. Based on role theory, researchers have focused on role conflict and role ambiguity as the two key ingredients of role stress. Role ambiguity is defined as an evaluation about the lack of salient information needed to perform a role effectively. Role conflict results from two or more sets of incompatible demands involving work-related issues. Employees are usually pursued work-roles more than one in work-focused organization. Too many work-roles and perceived uncertainties at employee's work can be obstacles to personal creativity. In an analysis of results, while role conflict is not negatively related significantly to creative self-efficacy, role ambiguity is negatively related significantly to creative self-efficacy. While role conflict is significantly related to personal creativity, role ambiguity is negatively related significantly to personal creativity. Creative self-efficacy mediates the relationship among role conflict, role ambiguity, and employee creativity. Personal initiative mediates the relationship between creative self-efficacy and employee creativity. This paper shows that creative self-efficacy and personal initiative are the driving force behind personal creativity. Organizations can get some implications of creative-related role conflict and role ambiguity that employees have experienced. As a result, organizations must not only encourage creativity of employees by greater involvement but also encourage their input towards their-focused own works and tasks. And employees should be developed to pace with the organizational needs and development. Management must enable employees to think of new ideas and practices that promotes personal creativity.

Study on the Thermal Stability of PEDOT/PSS Film Hybrided with Graphene Oxide (그래핀 옥사이드와 복합화한 PEDOT/PSS 필름의 열적 안정성에 관한 연구)

  • Choi, Jong Hyuk;Park, Wan-Su;Lee, Seong Min;Chung, Dae-won
    • Applied Chemistry for Engineering
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    • v.27 no.4
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    • pp.402-406
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    • 2016
  • In order to investigate the thermal stability of electro-conductive poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT/PSS), we have prepared films by casting PEDOT/PSS aqueous solution without using a binding material and measured surface resistances of the films while annealing at $200^{\circ}C$. Electrical properties of films were improved by annealing, and the maximum conductivity ($540S{\cdot}m^{-1}$) after annealing for 2 hrs was found to be approximately 3 times higher than that ($180S{\cdot}m^{-1}$) of the original film. The conductivities, however, dramatically decreased with an increase in annealing time and dissipated after 24 hrs of annealing. On the other hand, PEDOT/PSS films hybridized with graphene oxide (GO) displayed a salient improvement in conductivity by annealing, which was measured to be around $600S{\cdot}m^{-1}$ even after 30 hrs of annealing at $200^{\circ}C$. We tentatively conclude that hybridization with GO enhances the thermal stability of PEDOT/PSS.