• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.818-826
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• 2015

Recently, objective image quality assessment (IQA) methods that elaborately reflect the visual quality perception characteristics of human visual system (HVS) have actively been studied. Among those characteristics of HVS, luminance adaptation (LA) effect, indicating that HVS has different sensitivities depending on background luminance values to distortions, has widely been reflected into many existing IQA methods via Weber's law model. In this paper, we firstly reveal that the LA effect based on Weber's law model has inaccurately been reflected into the conventional IQA methods. To solve this problem, we firstly derive a new LA effect-based Local weight Function (LALF) that can elaborately reflect LA effect into IQA methods. We validate the effectiveness of our proposed LALF by applying LALF into SSIM (Structural SIMilarity) and PSNR methods. Experimental results show that the SSIM based on LALF yields remarkable performance improvement of 5% points compared to the original SSIM in terms of Spear rank order correlation coefficient between estimated visual quality values and measured subjective visual quality scores. Moreover, the PSNR (Peak to Signal Noise Ratio) based on LALF yields performance improvement of 2.5% points compared to the original PSNR.

• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1407-1418
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• 2014

Korean youth spend tremendous time in school for preparing for college admissions. Their academic achievement and overall satisfaction with their lives are affected by how well they adapt to life in school. Successful adaptation to school is important enough to affect a student's future social life. One of the factors that affect adaptation to school is the psychological condition of adolescent anxiety. Anxiety is one of the common mental disorders that appear in people who are not familiar with new environments. Anxiety is known to be related to behavioral problems, and problems with psychological and emotional adaptation. This condition is dramatically increased in adolescents.Parental conflict in particular is known to be a major factor in affecting youth anxiety. As parental conflict became more severe, children felt more negative emotions such as anger, sadness and worry. Moreover, when a child's issue caused the parental conflict, there were more side effects in the emotional condition of the child. This study shows how parental conflict affects a child's anxiety and a child's school life.This problem is analyzed through structural equation modeling.

• Advances in Computational Design
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• v.1 no.4
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• pp.315-327
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• 2016

Damage detection and localisation in structures is essential since it can be a means for preventive maintenance of those structures under service conditions. The use of structural modal data for detecting the damage is one of the most efficient methods. This paper presents comparative performance of various state-of-the-art meta-heuristics for use in structural damage detection based on changes in modal data. The metaheuristics include differential evolution (DE), artificial bee colony algorithm (ABC), real-code ant colony optimisation (ACOR), charged system search (ChSS), league championship algorithm (LCA), simulated annealing (SA), particle swarm optimisation (PSO), evolution strategies (ES), teaching-learning-based optimisation (TLBO), adaptive differential evolution (JADE), evolution strategy with covariance matrix adaptation (CMAES), success-history based adaptive differential evolution (SHADE) and SHADE with linear population size reduction (L-SHADE). Three truss structures are used to pose several test problems for structural damage detection. The meta-heuristics are then used to solve the test problems treated as optimisation problems. Comparative performance is carried out where the statistically best algorithms are identified.

• Korean Journal of Culture and Social Issue
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• v.27 no.4
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• pp.351-389
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• 2021

This qualitative study aimed to develop a structural framework that explains the process of psychological adaptation and sequential changes being perceived by Korean people under the COVID-19 Pandemic past year. Setting a tentative analysis frame induced from antecedent literatures about psychological phenomena during the COVID-19 pandemic, the qualitative data were collected from 6 Korean adults by semi structured individual interviews. For the data, content analysis applied from the grounded theory were performed. As a result, the initial framework was extended and revised to describe the psychological phenomena under the pandemic. This paradigm structure includes the process of 'causal factors ⇒ psychological main phenomena ⇒ sequential results' being intervened by personal contextual situations and psychological characteristics, as moderators. The category of causal factors were the COVID-19 pandemic, relevant critical incidents, and social distancing policy. The main phenomena reflected either positive, negative, or complicated experiences. The sequential psychological results included transformation of cognitive system or behavior patterns. Various variables such as psychological sense of community and social responsibility, psychological capability for leisure, and positive psychological capital were found out as moderating factors. In discussion and conclusion, theoretical/practical implications of the results and direction to study in the future were suggested.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.231-238
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• 2002

The AASHTO seismic base isolation design approach has been reviewed and modified to fit the nonlinear static analysis procedure for reinforced concrete structures in a simpler way. Such an adaptation may be possible for the fact that the reinforced concrete under development of damage due to earthquake loading keeps softening to result in period shifting toward longer side. The validity of the proposed approach was verified by applying it to the examples presented in the current state-of-the-practice approach.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.10
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• pp.63-70
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• 2019

The Busan branch of the former Toyo Takushoku Co. carried out the same business as a bank at the time of construction. This required an open space of long-span, which had no pillars, on the first floor where many customers frequently visited. In addition, an office space is required in the upper part, and a column is arranged so as to place a corridor in the center. It was designed with modern complex structures for space utilization and structural adaptation. As a result, scientific structural calculations of the modern era began and various structural technologies were introduced, the rationalization and value of various spatial characteristics and their structural design were analyzed from a technical historical perspective in the structure requiring long-span space. The Busan branch of the former Toyo Takushoku Co. is a complex structure with three structures. It is highly valuable as a building that tried to design its structure in a variety of spaces through calculation and introduction of new technology based on the principle of force in modern times.

• Smart Structures and Systems
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• v.32 no.3
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• pp.179-193
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• 2023

This study explores an alternative to the existing centralized process for data anomaly detection in modern Internet of Things (IoT)-based structural health monitoring (SHM) systems. An edge intelligence framework is proposed for the early detection and classification of various data anomalies facilitating quality enhancement of acquired data before transmitting to a central system. State-of-the-art deep neural network pruning techniques are investigated and compared aiming to significantly reduce the network size so that it can run efficiently on resource-constrained edge devices such as wireless smart sensors. Further, depthwise separable convolution (DSC) is invoked, the integration of which with advanced structural pruning methods exhibited superior compression capability. Last but not least, quantization-aware training (QAT) is adopted for faster processing and lower memory and power consumption. The proposed edge intelligence framework will eventually lead to reduced network overload and latency. This will enable intelligent self-adaptation strategies to be employed to timely deal with a faulty sensor, minimizing the wasteful use of power, memory, and other resources in wireless smart sensors, increasing efficiency, and reducing maintenance costs for modern smart SHM systems. This study presents a theoretical foundation for the proposed framework, the validation of which through actual field trials is a scope for future work.

• Computers and Concrete
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• v.33 no.4
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• pp.385-398
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• 2024

As concrete dominates the construction industry, alternatives to traditionally used steel reinforcement are being sought. This study explored the suitability of carbon fiber-reinforced polymer (CFRP) as a substitute within rigid frames, focusing on its impact on section ductility and overall structural durability against seismic events. However, current design guidelines address quasi-static loads, leaving a gap for dynamic or extreme circumstances. Our approach included multiscale simulations, parametric study, and energy dissipation analyses, drawing upon a unique adaptation of modified compression field theory. In our efforts to optimize macro and microparameters to improve yield strength, manage brittleness, and govern failure modes, we also recognized the potential of CFRP's high corrosion resistance. This characteristic of CFRP could significantly reduce the frequency of required repairs, thereby contributing to enhanced durability of the structures. The research reveals that CFRP's durability and seismic resistance are attributed to plastic joints within compressed fibers. Notably, CFRP can impart ductility to structural designs, effectively balancing its inherent brittleness, particularly when integrated with quasi-brittle materials. This research challenges the notion that designing bendable components with carbon fiber reinforcement is impractical. It shows that creating ductile bending components with CFRP in concrete is feasible despite the material's brittleness. This funding overturns conventional assumptions and opens new avenues for using CFRP in structural applications where ductility and resilience are crucial.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.317-324
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• 2004

Shape design optimization of shell structure is implemented on a basis of integrated framework of geometric modeling and finite element analysis which is constructed on the geometrically exact shell theory. This shell theory enables more accurate and robust analysis for complicated shell structures, and it fits for the nature of B-spline function which Is popular modeling scheme in CAD field. Shape of laminated composite shells is optimized through genetic algorithm and sequential linear programming, because there ire numerous optima for various configurations, constraints, and searching paths. Sequential adaptation of global and local optimization makes the process more efficient. Two different optimized results of laminated composite shell structures to minimize strain energy are shown for different layup sequence.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.1-8
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• 1994

An automated procedure which allows adaptation of spatial and time discretization simultaneously in finite element analysis of linear elastodynamic problems is presented. For dynamic problems having responses dominated by high frequency modes, such as those with impact, explosive, traveling and earthquake loads high gradient stress regions change their locations from time to time. And the time step size may need to vary in order to deal with whole process ranging from transient phase to steady state phase. As the sizes of elements in space vary in different regions, the procedure also permits different time stepping. In such a way, the best performance attainable by the finite element method can be achieved. In this study, we estimate both of the kinetic energy error and stran energy error induced by spatial and time discretization in a consistent manner. Numerical examples are used to demonstrate the performance of the procedure.