• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.489-502
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• 2022

This paper is aimed at developing an optimization-based Finite Element model updating approach for structural damage identification and quantification. A modal flexibility-based error function is introduced, which uses modal assurance criterion to formulate the updating problem as an optimization problem. Because of the inexplicit input/output relationship between the candidate solutions and the error function's output, a robust and efficient optimization algorithm should be employed to evaluate the solution domain and find the global extremum with high speed and accuracy. This paper proposes a new multi-stage Selective Particle Swarm Optimization (SPSO) algorithm to solve the optimization problem. The proposed multi-stage strategy not only fixes the premature convergence of the original Particle Swarm Optimization (PSO) algorithm, but also increases the speed of the search stage and reduces the corresponding computational costs, without changing or adding extra terms to the algorithm's formulation. Solving the introduced objective function with the proposed multi-stage SPSO leads to a smart feedback-wise and self-adjusting damage detection method, which can effectively assess the health of the structural systems. The performance and precision of the proposed method are verified and benchmarked against the original PSO and some of its most popular variants, including SPSO, DPSO, APSO, and MSPSO. For this purpose, two numerical examples of complex civil engineering structures under different damage patterns are studied. Comparative studies are also carried out to evaluate the performance of the proposed method in the presence of measurement errors. Moreover, the robustness and accuracy of the method are validated by assessing the health of a six-story shear-type building structure tested on a shake table. The obtained results introduced the proposed method as an effective and robust damage detection method even if the first few vibration modes are utilized to form the objective function.

• Journal of Korea Water Resources Association
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• v.47 no.11
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• pp.1017-1026
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• 2014

To investigate the effect of upstream dam operation and river water use on the downstream flows, SWAT-K watershed model was applied to the Paldang Dam watershed of the Han River basin. Analysis results from 2001 to 2009 showed that outflows from the multi-purpose dams such as the Soyanggang Dam and Chungju Dam much have a strong influence on the downstream flows during both the low- and high-flow seasons. This resulted an increase of low-flow at the Paldang Dam, the end of Pukhangang, and the Yangpyeong stage station by $100.57m^3/s$, $33.01m^3/s$, and $49.66m^3/s$, respectively. Whereas, the impact of river water use was hardly found in the Pukhangang, and also was not significant in the (Nam)hangang. Therefore, the effect of small dam such as the Hoengseong Dam or river water use would be able be excluded for long-term runoff analysis. But, in the case of the areas with a large amount of water use, a sufficient information such water-intake and water movement also must be taken into account like this study.

• Earthquakes and Structures
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• v.10 no.4
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• pp.939-963
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• 2016

According to the new directives about the rational and efficient use of energy, thermal bridges in buildings have to be avoided, and the thermal insulation (TI) layer should run without interruptions all around the building - even under its foundations. The paper deals with the seismic response of multi-storeyed reinforced concrete (RC) frame building structures founded on an extruded polystyrene (XPS) layer placed beneath the foundation slab. The purpose of the paper is to elucidate the problem of buildings founded on a TI layer from the seismic resistance point of view, to assess the seismic behaviour of such buildings, and to search for the critical parameters which can affect the structural and XPS layer response. Nonlinear dynamic and static analyses were performed, and the seismic response of fixed-base (FB) and thermally insulated (TI) variants of nonlinear RC building models were compared. Soil-structure interaction was also taken into account for different types of soil. The results showed that the use of a TI layer beneath the foundation slab of a superstructure generally induces a higher peak response compared to that of a corresponding system without TI beneath the foundation slab. In the case of stiff structures located on firm soil, amplification of the response might be substantial and could result in exceedance of the superstructure's moment-rotation plastic hinge capacities or allowable lateral roof and interstorey drift displacements. In the case of heavier, slenderer, and higher buildings subjected to stronger seismic excitations, the overall response is governed by the rocking mode of oscillation, and as a consequence the compressive strength of the XPS could be insufficient. On the other hand, in the case of low-rise and light-weight buildings, the friction capacity between the layers of the applied TI foundation set might be exceeded so that sliding could occur.

• Journal of the Korean housing association
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• v.24 no.6
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• pp.199-208
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• 2013

Developing a modern Han-style design and providing support for the commercialization development model in recent years has been propelled by the Han-style Support Strategies of the central government in conjunction with Han-style revitalization related projects that reflect the efforts of local governments. Han-style revitalization, the rekindling and revaluing of human behavior and interest in local governments following the social and cultural changes of the past decades, has emerged as an increasingly traditional area of concern in Han-style design. The purpose of the study was to provide a method which clarifies the design rules of the Han-style bathroom based on an evaluation of sensibilities and a rough set theory, and to give the components meaning and to systematize the method. Essentially, the Han-style bathroom design evaluation is a complex multi-criteria decision making process that seeks to improve the effectiveness and objectively of the Han-style bathroom design. Han-style bathroom design can be displayed in a graphical representation in response to input from the evaluation concerning sensibilities. Because the graphical representation is composed of 3D data, it is possible to display the Han-style bathroom design form in any desired perspective and also to perform shading and other operations. With the proposed method, it is possible to obtain a combination of several contributory components which can be referred to as Reducts, Covering Index and Column Score. Han-Style/Non Han-Style Bathroom Designs were identified by the combination of several components.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.122-129
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• 2004

The purpose of this study is to propose a way that improves the construction management for remodeling of building. The study attempts to deal with the case study for application and suggests some positive and negative lessons. The main contents and results of the study are as follows. (1) Through the repetitive joint meetings among the various participants, decision making for the remodeling process can be speeded up. (2) Clear work order and communication for work scope can be accomplished by using perspective drawing in design phase. (3) Reliable construction planning and scheduling for remodeling of building can be proposed through case study. (4) By a sound survey, conflict elements can be resolved in advance. Also reasonable procurement plan of equipments and multi-skilled labor can be important factors to keep a construction schedule in time. (5) Through the comparison a case project with other sites having a similar work scope, improvement effect in a time and cost aspect was analyzed quantitatively. The study also recommends that, as a future research, the remodeling process model be developed for more general applications in remodeling of building.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.179-193
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• 2023

It is undeniable that urban greenspace is the soul of a city. Conventional urban greenspace such as parks, community gardens, playgrounds etc. located within a city reduce the negative effects of pollution, play a major role in the survival of the urban ecosystem, and promote healthy lifestyles. Today, 55% of the world's population lives in urban areas, which is expected to increase to 68% by 2050. Projections show that urbanization and the gradual migration to urban areas combined with the fast growth of the world's population, could add another 2.5 billion people to urban areas by 2050 and almost 90% of this increase will take place in Asia(UN, 2018). As a result, many plots in the cities are and will continue to be occupied with buildings to provide residential support to the increased population. This will dangerously decrease urban greenspaces. Moreover, worldwide, food crisis, energy crisis, and social crisis is posing a great threat to the existence of mankind. Additionally, the COVID - 19 has introduced a new lifestyle where from work culture to community configuration has drastically transformed. In this scenario, residential buildings will have to serve more than just providing privacy and shelter. As urban greenspaces are being occupied by concrete residential buildings, these buildings will have to compensate for the percentage of urban green they are destroying and the issues they are imposing in the process. The goal of this thesis is to design, architecturally define and, categorize comprehensive 'sustainable Greenspace'(S.G.S) for the multi-family housing scenario. These will be different than the conventional green (veranda, rooftop green) we commonly see in residential buildings. An old, dilapidated apartment building will be the target of remodeling to fulfill the purpose of this thesis.

• The Journal of Society for e-Business Studies
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• v.14 no.2
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• pp.1-22
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• 2009

As Internet shopping is getting popular, "trust" has become an important factor for customers to select websites and have repurchase intention. "Trust" has been developed from uni-dimensional concept to multi-dimensional concept in e-Commerce area. From the multi-dimensional viewpoint, this study is to investigate the processes to build trust for online stores. For this purpose, this study classifies the concept of trust into cue-based trust and experience-based trust, and then investigates their relationship in online stores. This study also identifies factors that explain cue-based trust and experience-based trust. The result from questionnaire survey distinguished cue-based trust from experience-based trust and both trust concepts are correlated each other. Second, cue-based trust is explained by perceived size, perceived reputation, and return policy, while experience-based trust is done by navigation, information usefulness and interactivity.

• Research in Community and Public Health Nursing
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• v.31 no.3
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• pp.256-268
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• 2020

Purpose: This study aimed to explore ecological factors and strategies for childhood obesity prevention targeting vulnerable children using a community-based participatory research (CBPR) methodology. Methods: The CBPR was conducted by following basic process steps. Participants were 12 community stakeholders such as community child center directors (n=4), vulnerable children's mothers (n=3), community health center officials (n=2), and lay health advisors (n=4); they were purposively sampled from K municipal county in Seoul, South Korea. The qualitative content analysis was performed to explore main themes of the ecological factors and strategies by using data obtained from 5 times of focus group interview. Results: Twelve ecological factors associated with childhood obesity prevention were identified: Intrapersonal factors including emotional overeating; interpersonal factors including permissive parenting style of children's eating behaviors; organizational factors including social workers' less educational opportunities; and community/policy factors including less government financial support. Four ecological strategies for childhood obesity prevention were addressed: Developing obesity prevention programs targeting vulnerable children' lifestyles; promoting parents' active participation in education; building healthy meal service environments through empowering social workers; and building supportive community environment and securing community resources for child obesity prevention. Conclusion: Our findings may be informative in terms of providing a comprehensive understanding of multi-level ecological barriers against vulnerable children' obesity prevention and, moreover, guiding multi-level strategies for preventing childhood obesity targeting children enrolled in community child centers.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.572-583
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• 2020

The purpose of this study is to find out how to effectively utilize the public facilities site that is being used in the new town for the expansion of newly required public facilities, because it is difficult to carry out redevelopment projects in apartment complexes of 1st generation new town due to the rigidity of land use and macroeconomic conditions. This study examined the following three ways to effectively utilize existing public facilities sites for Pyeongchon new town. First, it suggested how to secure the parking lot by deciding multi-dimensional urban planning facility of public facilities such as parks and schools in superblock that lacks parking space of apartment complex. Second, it suggested a plan to accommodate the demands of public facilities required by increasing the building density of existing public buildings in commercial district as an example of the Anyang Tax Office. Lastly, it suggested a way to install additional functions required by users through the reorganization of the existing public facilities and some extensions by examining the Pyeongchon library.

• Structural Engineering and Mechanics
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• v.47 no.4
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• pp.471-493
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• 2013

This paper presents a framework for seismic damage evaluation for Algerian buildings adapted from HAZUS approach (Hazard-United States). Capacity and fragility curves were adapted to fit the Algerian building typologies (Reinforced Concrete structures, Confined or Non-Confined Masonry, etc). For prediction purposes, it aims to estimate the damages and potential losses that may be generated by a given earthquake in a prone area or country. Its efficiency is validated by comparing the estimated and observed damages in Boumerd$\grave{e}$s city, in the aftermath of Boumerd$\grave{e}$s earthquake (Algeria: May $21^{st}$ 2003; $M_w$ = 6.8). For this purpose, observed damages reported for almost 3,700 buildings are compared to the theoretical predictions obtained under two distinct modelling of the seismic hazard. In one hand, the site response spectrum is built according to real accelerometric records obtained during the main shock. In the other hand, the effective Algerian seismic code response spectrum (RPA 99) in use by the time of the earthquake is considered; it required the prior fitting of Boumerd$\grave{e}$s site PGA (Peak Ground Acceleration) provided by Ambraseys' attenuation relationship.