• Steel and Composite Structures
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• v.45 no.5
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• pp.683-695
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• 2022

Conventional braces are often used to provide stiffness to structures; however due to buckling they cannot be used as seismic energy dissipating elements. In this study, a seismic energy dissipation device is proposed which is comprised of a bracing member and a steel hysteretic damper made of steel hexagonal plates. The hexagonal shaped designated fuse causes formation of plastic hinges under axial deformation of the brace. The main advantages of this damper compared to conventional metallic dampers and buckling-restrained braces are the stable and controlled energy dissipation capability with ease of manufacture. The mechanical behavior of the damper is formulated first and a design procedure is provided. Next, the theoretical formulation and the efficiency of the damper are verified using finite element (FE) analyses. An analytical model of the damper is established and its efficiency is further investigated by applying it to seismic retrofit of a case study structure. The seismic performance of the structure is evaluated before and after retrofit in terms of maximum interstory drift ratio, top story displacement, residual displacement, and energy dissipation of dampers. Overall, the median of maximum interstory drift ratios is reduced from 3.8% to 1.6% and the residual displacement decreased in the x-direction which corresponds to the predominant mode shape of the structure. The analysis results show that the developed damper can provide cost-effective seismic protection of structures.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.540-553
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• 2007

Strategic management of changes is very significant for all types of construction projects. Project management teams must have the ability to respond to changes effectively in order to minimize their adverse impact on the project. The study focuses on the causes, their frequent effects and effective controls for changes in educational building projects. To achieve the study objectives, a questionnaire survey was carried out to collect relevant information. Through the literature review, 53 causes, 16 effects and 30 potential controls for change orders were identified. These provided the basis for the formulation of the questionnaire. Responses from 92 professionals who were involved in the educational projects in Singapore were analyzed. They included 28 developers, 33 consultants and 31 contractors. From the survey findings, the most important causes of changes were identified. The study revealed the most frequent effects and most effective controls for each cause of change order. Arising therefrom, a comprehensive tabulation of the 53 causes and their frequent effects and effective controls was also developed. A timeline for implementing the controls was developed through in-depth interviews with the professionals. The study would assist building professionals in taking proactive measures for reducing change orders for educational buildings; furthermore, the timeline would also be helpful for them to implement controlling strategies at the appropriate time. Recommendations were suggested based on the research findings.

• The Journal of Economics, Marketing and Management
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• v.11 no.4
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• pp.53-63
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• 2023

Purpose: The purpose of this study is to examine the research trends in the papers published by Korean researchers related to traditional markets, to check what topics have been studied, and to make various suggestions for research directions and effective ways to revitalize traditional markets. Research design, data and methodology: To this end, this study conducted word frequency analysis, co-occurrence frequency analysis, BERTopic, LDA, dynamic topic modeling and OLS regression analysis using Python 3.7 on the English abstracts of a total of 502 papers extracted through ScienceON. Results: As a result of word frequency analysis and co-occurrence frequency analysis, it was found that studies related to traditional markets have been conducted not only on factors related to customers, but also on traditional market merchants and government policies, and the degree of service, quality, and satisfaction perceived by customers using traditional markets. Through BERTopic and LDA, three topics such as 'Traditional market safety management' were identified, and among them, it was found that 'Traditional market safety management' is relatively less attention by researchers. Conclusions: The results of this study suggest that future research on the revitalization of traditional markets should be conducted from a specific consulting perspective along with the establishment of various data, a causal model study from various perspectives such as the characteristics of merchants as well as consumers, and an integrated and convergent approach to policy formulation by the government and local governments.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.2
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• pp.73-78
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• 2023

The cosmetics industry faces a significant challenge in addressing the decreased recycling rate of cosmetic containers due to the composite materials used to meet consumers' aesthetic satisfaction. To address thees issues, eco-friendly packaging solutions such as refill packaging and single-material use have been developed. However, the market for eco-friendly cosmetics packaging requires a product that meets consumers' demands for aesthetics, sensitivity, and eco-friendliness while also performing as well as existing products. This study presents a solution to the challenge of the decreased recycling rate of cosmetic containers by developing a new cosmetic packaging product for cream formulations. The product features an easily separable and dischargeable internal refill container, while maintaining the design aesthetics of the external container. Through various tests, the product was shown to be of equivalent quality and performance to existing cream cosmetic packaging, with no leakage or defects observed. Furthermore, the use of a single-material polypropylene refill container is expected to contribute to the improvement of the plastic recycling rate.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.3
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• pp.101-109
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• 1995

Axisymmetric and quasi-static finite element analysis of an inflated tire rotating with constant angular velocity and contact to road has been performed. Centrifugal force effect was added to load stiffness matrix and equation of effective material properties were calculated by the Halpin-Tsai formulation. In this report, radial truck/bus tire was analyzed. It was inflated and rotated at speeds up to 140 km/h. Then, contact problem was performed to calculate stress-strain field of tire wiht flat rigid road under the load due to the self-weight of a vehicle. Significant changes of stress-strain field of tire were observed in the finite element analysis. Shear stress, strain and strain energy density were rapidly increased at the dege of #2 belt at freely rotating state. This concentrated stress and strain made belt edge sparation. Under the condition of flat riged road contact, strain energy density of #2 belt, carcass turn-up part were concentrated and bigger values than only freely rotation state. Therefore, dynamic behaivor of tire has to considered as design factors which are affected to belt edge separation and bead breakage.

• Steel and Composite Structures
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• v.46 no.3
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• pp.293-318
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• 2023

This study aims to examine the elastic stiffness properties of Elliptic-Braced Moment Resisting Frame (EBMRF) subjected to lateral loads. Installing the elliptic brace in the middle span of the frames in the facade of a building, as a new lateral bracing system not only it can improve the structural behavior, but it provides sufficient space to consider opening it needed. In this regard, for the first time, an accurate theoretical formulation has been developed in order that the elastic stiffness is investigated in a two-dimensional single-story single-span EBMRF. The concept of strain energy and Castigliano's theorem were employed to perform the analysis. All influential factors were considered, including axial and shearing loads in addition to the bending moment in the elliptic brace. At the end of the analysis, the elastic lateral stiffness could be calculated using an improved relation through strain energy method based on geometric properties of the employed sections as well as specifications of the utilized materials. For the ease of finite element (FE) modeling and its use in linear design, an equivalent element was developed for the elliptic brace. The proposed relation was verified by different examples using OpenSees software. It was found that there is a negligible difference between elastic stiffness values derived by the developed equations and those of numerical analysis using FE method.

• The Journal of Economics, Marketing and Management
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• v.11 no.6
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• pp.35-41
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• 2023

Purpose: This study aims to determine the marketability of the heritage sites in Region III, Philippines. More specifically, it will obtain information on the: (a) profile of the heritage sites in Central Luzon; (b) dimensional issues of their marketability along social, environmental, and economic lines; (c) quality of services in terms of tangibility, responsiveness, empathy, assurance, and reliability; and (d) its business model canvas. Research design, data, and methodology: This will utilize a descriptive survey of the heritage sites in Central Luzon, namely: Aurora, Nueva Ecija, Bulacan, Pampanga, Tarlac, Zambales, and Bataan. There will be 60 respondents, including 5 facilitators, 24 residents, and 31 tourists. The results will be statistically measured through the measures of central tendencies, dispersion, and the test of significance. Result and conclusion: This study will comprehensively examine the local tourism sector, benefiting various stakeholders. It serves as a valuable resource for tourists by providing insights into destination marketing strategies and enhancing heritage tourism experiences. Administrators benefit from coping strategy evaluations, aiding in the formulation of effective strategies aligned with industry goals. Tourism businesses align with industry objectives and the study streamlines ordinances for site protection for local government units. Additionally, the community gains empowerment through insights into employable activities and potential businesses, influencing assessments of the justification for local preservation ordinances.

• Steel and Composite Structures
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• v.50 no.1
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• pp.15-24
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• 2024

This research presents dynamical reaction investigation of pore-dependent and nano-thickness beams having functional gradation (FG) constituents exposed to a movable particle. The nano-thickness beam formulation has been appointed with the benefits of refined high orders beam paradigm and nonlocal strain gradient theory (NSGT) comprising two scale moduli entitled nonlocality and strains gradient modulus. The graded pore-dependent constituents have been designed through pore factor based power-law relations comprising pore volumes pursuant to even or uneven pore scattering. Therewith, variable scale modulus has been thought-out until process a more accurate designing of scale effects on graded nano-thickness beams. The motion equations have been appointed to be solved via Ritz method with the benefits of Chebyshev polynomials in cosine form. Also, Laplace transform techniques help Ritz-Chebyshev method to obtain the dynamical response in time domain. All factors such as particle speed, pores and variable scale modulus affect the dynamical response.

• The Journal of Industrial Distribution & Business
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• v.15 no.9
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• pp.29-35
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• 2024

Purpose: With the rapid development of the e-commerce industry, online e-commerce festivals represented by the "Double Eleven Online Shopping Festival" and "618 Mid-Year Promotion" in China play a unique role in consumer activities and have an important impact on various consumers. As aborigines in the Internet era, college students have huge consumption potential. In order to meet the pursuit of a better life for college students and achieve impressive business results, e-commerce platforms will launch various e-commerce festivals. Research design, data and methodology: This article constructs a research model based on the stimulus organism response model and clue utilization theory, proposes relevant hypotheses, and uses SPSS 27.0 to test the proposed hypotheses. From the perspectives of promotion level, timeliness, and variety of categories, this study aims to verify the impact of e-commerce festivals on college students' purchasing intentions and draw relevant conclusions. Results: Empirical verification has shown that the promotion level, timeliness, variety of categories, and holiday trust of e-commerce festivals have a significant positive impact on the e-commerce festival trust of college students as a consumer group. Conclusions: The conclusion on college students' purchasing intentions not only has guiding significance for the formulation of marketing strategies for enterprises, but also helps to understand the current behavior patterns of young consumers.

• Steel and Composite Structures
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• v.52 no.5
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• pp.501-513
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• 2024

Two-directional functionally graded materials (2D-FGMs) show extraordinary physical properties which makes them ideal candidates for designing smart micro-switches. Pull-in instability is one of the most critical challenges in the design of electrostatically-actuated microswitches. The present research aims to bridge the gap in the static pull-in instability analysis of microswitches composed of 2D-FGM. Euler-Bernoulli beam theory with geometrical nonlinearity effect (i.e. von-Karman nonlinearity) in conjunction with the modified couple stress theory (MCST) are employed for mathematical formulation. The micro-switch is subjected to electrostatic actuation with fringing field effect and Casimir force. Hamilton's principle is utilized to derive the governing equations of the system and corresponding boundary conditions. Due to the extreme nonlinear coupling of the governing equations and boundary conditions as well as the existence of terms with variable coefficients, it was difficult to solve the obtained equations analytically. Therefore, differential quadrature method (DQM) is hired to discretize the obtained nonlinear coupled equations and non-classical boundary conditions. The result is a system of nonlinear coupled algebraic equations, which are solved via Newton-Raphson method. A parametric study is then implemented for clamped-clamped and cantilever switches to explore the static pull-in response of the system. The influences of the FG indexes in two directions, length scale parameter, and initial gap are discussed in detail.