• Steel and Composite Structures
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• v.36 no.4
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• pp.427-446
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• 2020

This paper carries out the progressive collapse analysis of stainless steel composite beam-to-column joint sub-models and moment-resisting frames under column removal scenarios. The static flexural response of composite joint sub-models with damaged columns was initially explored via finite element methods, which was validated by independent experimental results and discussed in terms of moment-rotation relationships, plastic hinge behaviour and catenary actions. Simplified finite element methods were then proposed and applied to the frame analysis which aimed to elaborate the progressive collapse response at the frame level. Nonlinear static and dynamic analysis were employed to evaluate the dynamic increase factor (DIF) for stainless steel composite frames. The results suggest that the catenary action effect plays an important role in preventing the damaged structure from dramatic collapse. The beam-to-column joints could be critical components that influence the capacity of composite frames and dominate the determination of dynamic increase factor. The current design guidance is non-conservative to provide proper DIF for stainless steel composite frames, and thus new DIF curves are expected to be proposed.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.89-99
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• 2007

In this paper, an analytic model of a sleep mode operation in the IEEE 802.16e is investigated. A mobile subscriber station(MSS) goes to sleep mode after negotiations with the base station(BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/l with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Geomechanics and Engineering
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• v.22 no.6
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• pp.509-518
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• 2020

Multi-layered primary linings have been proved to be highly effective for tunneling in severe squeezing grounds. But there still has not existed well-established design method for it. Basically, there are two main critical problems in this method, including determinations of allowable deformation and distribution of support stiffness. In order to address such problems, an attempt to investigate the mechanical response of a circular tunnel with double primary linings is performed in this paper. Analytical solutions in closed form for stresses and displacements around tunnels are derived. In addition, the effectiveness and reliability of theoretical formulas provided are well validated by using the numerical method. Finally, based on the analytical solutions, a parametric investigation on the effects of allowable deformation and distribution of support stiffness on tunnel performance is conducted. Results show that the rock pressure and displacement are significantly affected by these two design parameters. It can be found that rock pressure decreases as either allowable deformation increases or stiffness of the first primary lining decreases, but rock displacement shows an opposite trend. This paper can provide a useful guidance for the design of multi-layered primary linings.

• The Korean Journal of Applied Statistics
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• v.29 no.5
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• pp.773-786
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• 2016

Multiple quantile regression that simultaneously estimate several conditional quantiles of response given covariates can provide a comprehensive information about the relationship between the response and covariates. Some quantile estimates can cross if conditional quantiles are separately estimated; however, this violates the definition of the quantile. To tackle this issue, multiple quantile regression with non-crossing constraints have been developed. In this paper, we carry out a comparison study on several popular methods for non-crossing multiple linear quantile regression to provide practical guidance on its application.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.795-800
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• 2007

In the previous study, a simple but effective analysis procedure, named as an Improved Modal Pushover Analysis (IMPA) was proposed to estimates the seismic capacities of multi-span continuous bridge structures, on the basis of the modal pushover analysis which considers all the dynamic modes of a structure. Differently from other previous studies, IMPA maintains the simplicity of the capacity-demand curve method and also gives a better estimation of the maximum dynamic response of a structure. Nevertheless, its applicability has never been approved for multi-span continuous bridges with large differences in the length of their adjacent piers. This paper, accordingly, concentrates on a parametric study to verify the efficiency and limitation in application of IMPA through a correlation study between various analytical models including the Equivalent Single Degree Of Freedom (ESDOF) and Modal Pushover Analysis (MPA) usually used in the seismic design of structures. Based on the obtained numerical results, this paper introduces a practical guidance and/or limitation for using IMPA to predict the seismic response of a bridge effectively.

• Human Ecology Research
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• v.57 no.4
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• pp.535-544
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• 2019

This study analyzes the need for appropriate response education in schools for national health and sustainable development education in connection with particulate matter, which has recently emerged as a serious environmental and social problem. The survey was conducted on 1,200 teenagers(middle and high school students) in North Jeolla Province. The results of the study are as follows. First, the survey results were generally low in terms of environmental attitude and response(actuality) as well as the level of knowledge of particulate matter. Second, particulate matter-related education is rarely conducted at school sites; therefore, it is also necessary to develop an environmental education programs that can be a significant educational experience along with a specific educational orientation that is required to ensure the achievement of sustainable residential environment education. Finally, we hope that this study will help raise awareness on sustainable residential environment education amid difficulties in accessibility. Issues that need further study include: the absence of education materials, environmental education related to particulate matter, and guidance on how to maintain healthy living for individuals that help increase interest in a sustainable living environment for future generations.

• Journal of Information Technology Applications and Management
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• v.28 no.3
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• pp.109-125
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• 2021

For the government of president Moon's AI SW HRD policy, he proclaimed AI democracy that anyone can utilize artificial intelligence technology to spread AI education for the people of the country. Through cognitive map analysis, this study presents expected policy outcomes due to the input of policy factors to overcome crisis factors and utilize opportunity factors. According to the cognitive guidance analysis, first, the opportunity factor is recognized as accelerating the digital transformation to Covid 19 if AI SW HRD is well nurtured. Second, the crisis factor refers to the rapid paradigm shift caused by the intelligence information society, resulting in job losses in the manufacturing sector and deepening imbalance in manpower supply and demand, especially in the artificial intelligence sector. Third, the comprehensive cognitive map shows a circular process for creating an AI SW ecosystem in response to threats caused by untact caused by Corona and a circular process for securing AI talent in response to threats caused by deepening imbalance in manpower supply and demand in the AI sector. Fourth, in order to accelerate the digital circulation that has been accelerated by Corona, we found a circular process to succeed in the Korean version of digital new deal by strengthening national and corporate competitiveness through AI-utilized capacity and industrial and regional AI education. Finally, the AI utilization empowerment strengthening rotation process is the most dominant of the four mechanisms, and we also found a relatively controllable feedback loop to obtain policy outputs.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3591-3598
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• 2023

Photoneutron background spectroscopy observations at linac are essential for directing accelerator shielding and subtracting background signals. Therefore, we constructed a Bonner Sphere Spectrometer (BSS) system based on an array of BF₃ gas proportional counter tubes. Initially, the response of the BSS system was simulated using the MCNP5 code. Next, the response of the system was calibrated by using neutrons with energies of 2.86 MeV and 14.84 MeV. Then, the system was employed to measure the spectrum of the ²⁴¹Am-Be neutron source, and the results were unfolded by using the Gravel and EM algorithms. Using the validated system, the undesirable neutron spectrum of the 120 MeV electron linac was finally measured and acquired. In addition, it is demonstrated that the equivalent undesirable neutron dose at a distance of 3.2 m from the linac is 19.7 mSv/h. The results measured by the above methods could provide guidance for linac-related research.

• Journal of Distribution Science
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• v.22 no.4
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• pp.69-77
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• 2024

Purpose: This paper aims to tackle the challenges and opportunities of cities' response to COVID-19 and provide cities with policy implications for better adapting to the post-pandemic era. Cities around the world are facing new challenges and have had to adapt to maintain social distancing measures while also addressing equity and social inclusion issues. Research design, data and methodology: The research methodology relies on an examination of existing literature, coupled with trend analysis employing discourse analysis to investigate post-pandemic urban resilience. The article also attempts to employ the concepts of adaptive urbanism and spatial flexibility and their potential to address these challenges not only in response to the pandemic, but also in the long-term. Results: The article explores the impact of COVID-19 on urban spatial structure through a public health lens and proposes actions that cities are able to take to enhance their resilience in the aftermath of the pandemic. Conclusions: It underscores the significance of reconstructing with improved distribution dynamics and provides valuable guidance for companies and policymakers on navigating these challenges. Ultimately, it also suggests that the pandemic has initiated a worldwide restructuring of urban planning, potentially leading to the emergence of smart cities grounded in science and technology.

• International Journal of Quality Innovation
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• v.4 no.1
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• pp.175-190
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• 2003

This paper discusses the determinants of green practices and incorporates some empirical findings from a recent study in the petrochemical sector in the Republic of Trinidad and Tobago. The study was comprised of a survey and follow-up interviews with senior executives who participated in the survey. Of fourteen companies involved, the findings affirmed that the investigation of accidents, provision of an emergency response, employee training, decreasing the production of wastes, and pre-treating wastes before disposal should be stressed. Government requirement, the economic reasons and public pressures were the driving forces of green practices. The five most important determinants identified include performance evaluation, financial justification, impacts on company, management leadership and operations integration. Implementing environmental management systems as a feasible approach to green practices in the petrochemical sector was explored. The findings provide guidance that helps organisations to accommodate the determinants of green practices into achieving sustainable environmental goals.