• Wind and Structures
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• v.23 no.3
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• pp.253-273
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• 2016

Ice accretions on stay cables may result in the instable vibration of galloping, which would affect the safety of cable-stayed bridges. A large number of studies have investigated the galloping vibrations of transmission lines. However, the obtained aerodynamics in transmission lines cannot be directly applied to the stay cables on cable-stayed bridges. In this study, linear and nonlinear single degree-of-freedom models were introduced to obtain the critical galloping wind velocity of iced stay cables where the aerodynamic lift and drag coefficients were identified in the wind tunnel tests. Specifically, six ice shapes were discussed using section models with geometric scale 1:1. The results presented obvious sudden decrease regions of the aerodynamic lift coefficient for all six test models. Numerical analyses of iced stay cables associated to a medium-span cable-stayed bridge were carried out to evaluate the potential galloping instability. The obtained nonlinear critical wind velocity for a 243-meter-long stay cable is much lower than the design wind velocity. The calculated linear critical wind velocity is even lower. In addition, numerical analyses demonstrated that increasing structural damping could effectively mitigate the galloping vibrations of iced stay cables.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.3 s.26
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• pp.211-218
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• 2006

Recently, many ships such as fishing boats, cargo ships, high speed ferry boats are visiting Mokpo harbor. In particular, many marine accidents have been occurred at this area due to the narrow channel, a thick fog, the existing of the shallow waters etc. However there is no suitable ships' routeing system which takes account of today's traffic situations in this area. This study aims at the settling of hazardous factors to mitigate the danger to vessels in Mokpo harbor and to secure the safety of maritime environment.

• Steel and Composite Structures
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• v.18 no.2
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• pp.357-374
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• 2015

Orthotropic decks composed of deck plate, ribs, cross beams and wearing surface are frequently used in industry to span long distances due to their light structures and load carrying capacities. As a result they are broadly preferred in industry and there are a lot of bridges of this type exist in the world. Nevertheless, some of them cannot sustain the anticipated service life and damages in form of cracks develop in steel components and wearing surface. Main reason to these damages is seen as the repetitive wheel loads, namely the fatigue loading. Solutions to this problem could be divided into two categories: qualitative and quantitative. Qualitative solutions may be new design methodologies or innovative materials, whereas quantitative solution should be arranging dimensions of deck structure in order to resist wheel loads till the end of service life. Wearing surface on deck plate plays a very important role to avoid or mitigate these damages, since it disperses the load coming on deck structure and increases the bending stiffness of deck plate by forming a composite structure together with it. In this study the effect of Elastic moduli, Poisson ratio and thickness of wearing surface on the stresses emerged in steel deck and wearing surface itself is investigated using a FE-model developed to analyze orthotropic steel bridges.

• Earthquakes and Structures
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• v.10 no.1
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• pp.239-260
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• 2016

Tuned mass dampers (TMDs) have been frequently proposed to mitigate the detrimental effects of dynamic loadings in structural systems. The effectiveness of this protection strategy has been demonstrated for wind-induced vibrations and, to some extent, for seismic loadings. Within this framework, recent numerical studies have shown that beneficial effects can be achieved by placing a linear TMD on the roof of linear elastic structural systems subjected to pulse-like ground motions. Motivated by these positive outcomes, closed-form design formulations have been also proposed to optimize the device's parameters. For structural systems that undergo a near-fault pulse-like ground motion, however, it is unlikely that their dynamic response be linear elastic. Hence, it is very important to understand whether such strategy is effective for inelastic structural systems. In order to provide new useful insights about this issue, the paper presents statistical results obtained from a numerical study conducted for three shear-type hysteretic (softening-type) systems having 4, 8 and 16 stories equipped with a linear elastic TMD. The effectiveness of two design procedures is discussed by examining the performances of the protected systems subjected to 124 natural pulse-like earthquakes.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.47-58
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• 2001

Evaluation of Freeway Congestion Management Using Mesoscopic Traffic Simulator A mesoscopic simulation study to measure the effects of trip generation caused by rampant expansion of residential area around the Kyungbu corridor has been conducted. Some alternatives, which seem to be judgememtally plausible and technically feasible to mitigate such congestion, have been carefully examined and evaluated by the simulation model called INTEGRATION. Alternatives are mostly network improvements. Banpo IC dedicated ramp construction (A1), Seocho IC TSM based weaving elimination (A2), dedicated local and express separation over Seocho-Yangjae segment (A3), Heonleung IC (A4) and Daewang If installations (A5), Pangyo IC improvement (A6), Baikhyun IC (A7) and Dongbaek IC installations (A8) along with Shingal-Pangyo segment capacity addition (A9). The most capital intensive ones are A9, A5, and A4 in that order. A1, A6, A7, and A8 are short in distance but they are also capital intensive and need some construction periods. The least capital driven alternatives are h2 and A3, the h2 is easier to do, but A3 needs traffic diversion scheme during construction. The A1, A7, and A8 have been identified cost effective in terms of speed increase and travel time saving. Along with these results, some limitations and future research agenda regarding simulation have also been presented.

• Asian Journal for Public Opinion Research
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• v.9 no.4
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• pp.310-330
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• 2021

Driven by the need for remote learning, the COVID-19 pandemic led to the rise of use of videoconferencing tools. Scholars began noticing an emerging phenomenon of feeling tired and exhausted during virtual meetings. This study determined the predictors of videoconference or Zoom fatigue among nursing students in a large, private, non-sectarian university in the Philippines. This cross-sectional online survey involves 597 nursing students in the Philippines using the Zoom Exhaustion and Fatigue Scale. Multiple linear regression analysis was used to examine predictors of videoconference fatigue. Results indicated that nursing students experienced high levels of videoconference fatigue. Gender, self-reported academic performance, Internet connection stability, attitude toward videoconferencing, frequency, and duration of videoconferences predicted videoconference fatigue. The regression model explained 25.3% of the variances of the videoconference fatigue. Videoconference fatigue is relatively prevalent and may be taking its toll on nursing students. Developing strategic interventions that can protect or mitigate the impact of fatigue during virtual meetings is needed.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.11
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• pp.21-29
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• 2021

The objective of this study is to see how a country's level of democracy impacts the relationship between financial development and income disparity. We argue that political regimes, supported by their degree of democracy, are important for various decentralization theories to predict the impact of financial development on income inequality. Our study tests this argument using Vietnam time series data for the period 2000-2020 through the ARDL model. The financial development variable is represented by five proxies, the income inequality variable is represented by the GINI coefficient and the role of democracy is represented by the Freedom House Index. Data serving for the study is taken from data sources with high reliability. The results of the study have strong evidence that (1) financial development has a positive impact on income inequality, (2) democratic government will reduce national income inequality. (3) And a higher degree of democracy tends to mitigate the positive impact of financial development on income inequality. Thus, our study contributes to the literature by providing a new look at the mixed results regarding the relationship between financial development and theoretical income inequality. Finally, the article provides policy implications for the Government of Vietnam.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3750-3770
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• 2021

This study investigates open-source dynamic XSS filters used as security devices in web applications to account for the effectiveness of filters in protecting against XSS attacks. The experiment involves twelve representative filters, which are examined individually by placing them into the final output function of a custom-built single-input-form web application. To assess the effectiveness of the filters in their tasks of sanitizing XSS payloads and in preserving benign payloads, a black-box testing method is applied using an automated XSS testing framework. The result in working with malicious and benign payloads shows an important trade-off in the filters' tasks. Because the filters that only check for dangerous or safe elements, they seem to neglect to validate their values. As some safe values are mistreated as dangerous elements, their benign payload function is lost in the way. For the filters to be more effective, it is suggested that they should be able to validate the respective values of malicious and benign payloads; thus, minimizing the trade-off. This particular assessment of XSS filters provides important insight regarding the filters that can be used to mitigate threats, including the possible configurations to improve them in handling both malicious and benign payloads.

• Journal of Korea Trade
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• v.25 no.4
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• pp.60-87
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• 2021

Purpose - This study examines the role of e-commerce resulting from technological innovation as a new approach toward internationalization. We study the relationship between e-commerce export and country distance, measured in CAGE distance, which has hindered traditional internationalization. As a control variable, entrepreneurship was introduced to check the moderating effect on the relationship between country distance and e-commerce export. Design/methodology - Based on empirical analysis, e-commerce exports from the Republic of Korea to 96 countries were used as dependent variables. First, hierarchical regression analysis was conducted to test the hypothesis about each country's distance, measured by CAGE distance, and each dimension of CAGE, on e-commerce exports. Next, the hypothesis was tested through the interaction term to examine the moderating effect of entrepreneurship. Findings - The analysis showed that the hypothesis, which postulated e-commerce exports as affected negatively by the country's distance, was supported but not that all CAGE dimensions affected it. Specifically, geographical distance and economic distance have negative effects, but cultural distance and administrative distance did not affect e-commerce exports. Thus, in contrast to the expectation that distance restrictions in e-commerce would not exist, this study confirmed that distance still matters to internationalization and that entrepreneurship can mitigate the adverse effects. Originality/value - Through these results, when export firms try to enter new markets and start internationalization through e-commerce, the entrepreneurship of the importing country should be considered.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.9
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• pp.79-89
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• 2021

Green finance plays an important role in environmental protection missions and fighting climate change. The Environment Fund in Vietnam is the main channel of preferential capital offered to firms for environmental protection. Unfortunately, it was previously unknown which criteria influenced these companies' ability to obtain green financing. Using a survey method, we collected data through a structured questionnaire of 203 respondents that represent firms that had received concessional loans from 26 Environment Funds. A Multiple Linear Regression model was used to examine the determinants of access to concessional loans for environmental protection. We found relationships between age, size, ownership type, and industry sector, and access to green finance. Third-party guarantees were a significant factor in financing through Environment Funds. Moreover, we found commercial environmental projects face fewer green financing obstacles. Surprisingly, showing audited financial statements does not mitigate the information asymmetry between firms and these financial institutions. These findings suggest that Environment Funds should classify environmental project types to develop appropriate lending policies. In emerging markets, enterprises need to build a trusted relationship with financial institutions so that they can replace asset-based lending techniques, thereby increasing the firms' accessibility to green finance.