• 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 Internet of Things and Convergence
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• v.9 no.6
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• pp.45-50
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• 2023

In software development, the elicitation and analysis of requirements is a crucial phase, and it involves considerable time and effort due to the involvement of various stakeholders. ChatGPT, having been trained on a diverse array of documents, is a large language model that possesses not only the ability to generate code and perform debugging but also the capability to be utilized in the domain of software analysis and design. This paper proposes a method of requirements engineering that leverages ChatGPT's capabilities for eliciting software requirements, analyzing them to align with system goals, and documenting them in the form of use cases. In software requirements engineering, it suggests that stakeholders, analysts, and ChatGPT should engage in a collaborative model. The process should involve using the outputs of ChatGPT as initial requirements, which are then reviewed and augmented by analysts and stakeholders. As ChatGPT's capability improves, it is anticipated that the accuracy of requirements elicitation and analysis will increase, leading to time and cost savings in the field of software requirements engineering.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.927-933
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• 2023

In modern times, with advances in semiconductor technology such as electronic devices, the need to improve the quality of onboard equipment with advanced electronic parts in automobiles, drones, airplanes, projectiles, and various fields, and reduce the impact of various disturbances on onboard equipment is becoming more important. Vibration control through hardware must be determined to prevent damage and improve quality to equipment operating in various environments such as automobiles, drones, airplanes, and projectiles. This study focuses on the study of vibration damping systems to protect mounted equipment from various disturbances and improve stability. Dynamic characteristics analysis, including compressive stiffness, damping rate, and frequency response, and vibration characteristics in the frequency domain of rubber dampers were identified through FEM analysis to identify the characteristics of rubber dampers. Through these findings, we would like to present the criteria for selecting a suitable rubber damper under various disturbance conditions.

• Journal of Industrial Convergence
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• v.22 no.1
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• pp.95-103
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• 2024

The purpose of this study was to examine the perceptions and beliefs of physical education teachers regarding learner-centered physical education and to qualitatively explore the stories of physical education teachers that appear in the field of practicing physical education curriculum. The research method was qualitative research, and data were collected and recorded through semi-structured questionnaires, individual interviews, group interviews, and metaphor records, and the data were analyzed through domain analysis and classification analysis. The study was able to derive results by dividing them into 'learner focus', 'overall development', and learning evaluation' in relation to physical education teachers' meaning construction of learner-centered physical education. And the practice of learner-centered physical education and its limitations were presented. In conclusion, the holistic development of learner-centered physical education includes addressing physical, cognitive, social, and emotional aspects. It is believed that this approach will not only measure student progress but also actively contribute to their development as individuals.

• Steel and Composite Structures
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• v.51 no.1
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• pp.73-91
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• 2024

This paper has focused on presenting vibration analysis of trapezoidal sandwich plates with a damaged core and FG wavy CNT-reinforced face sheets. A damage model is introduced to provide an analytical description of an irreversible rheological process that causes the decay of the mechanical properties, in terms of engineering constants. An isotropic damage is considered for the core of the sandwich structure. The classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. The First-order shear deformation theory of plate is utilized to establish governing partial differential equations and boundary conditions for the trapezoidal plate. The governing equations together with related boundary conditions are discretized using a mapping-generalized differential quadrature (GDQ) method in spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained using GDQ method. Validity of the current study is evaluated by comparing its numerical results with those available in the literature. After demonstrating the convergence and accuracy of the method, different parametric studies for laminated trapezoidal structure including carbon nanotubes waviness (0≤w≤1), CNT aspect ratio (0≤AR≤4000), face sheet to core thickness ratio (0.1 ≤ ${\frac{h_f}{h_c}}$ ≤ 0.5), trapezoidal side angles (30° ≤ α, β ≤ 90°) and damaged parameter (0 ≤ D < 1) are carried out. It is explicated that the damaged core and weight fraction, carbon nanotubes (CNTs) waviness and CNT aspect ratio can significantly affect the vibrational behavior of the sandwich structure. Results show that by increasing the values of waviness index (w), normalized natural frequency of the structure decreases, and the straight CNT (w=0) gives the highest frequency. For an overall comprehension on vibration of laminated trapezoidal plates, some selected vibration mode shapes were graphically represented in this study.

• Clinical Nutrition Research
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• v.12 no.2
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• pp.126-137
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• 2023

Hemodialysis (HD) patients face a common problem of malnutrition due to poor appetite. This study aims to verify the appetite alteration model for malnutrition in HD patients through quantitative data and the International Classification of Functioning, Disability, and Health (ICF) framework. This study uses the Mixed Method-Grounded Theory (MMGT) method to explore various factors and processes affecting malnutrition in HD patients, create a suitable treatment model, and validate it systematically by combining qualitative and quantitative data and procedures. The demographics and medical histories of 14 patients were collected. Based on the theory, the research design is based on expansion and confirmation sequence. The usefulness and cut-off points of the creatinine index (CI) guidelines for malnutrition in HD patients were linked to significant categories of GT and the domain of ICF. The retrospective CIs for 3 months revealed patients with 3 different levels of appetite status at nutrition assessment and 2 levels of uremic removal. In the same way, different levels of dry mouth, functional support, self-efficacy, and self-management were analyzed. Poor appetite, degree of dryness, and degree of taste change negatively affected CI, while self-management, uremic removal, functional support, and self-efficacy positively affected CI. This study identified and validated the essential components of appetite alteration in HD patients. These MM-GT methods can guide the selection of outcome measurements and facilitate the perspective of a holistic approach to self-management and intervention.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.81-90
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• 2024

The purpose of this study is to examine the possibility of combining DOOH advertising, which has fully met the functional requirements of a standalone digital medium, with transmedia storytelling as a expansion of a new advertising area. This researcher examined the concept of transmedia storytelling used in various fields and its application cases in dramas, movies, and webtoons, and analyzed examples of transmedia storytelling approaches in the field of advertising. As a result of the analysis, it was analyzed that although OOH advertising has brought many changes in the way of content implementation with the advent of digital signage, DOOH advertising needs to be approached in a more diverse way in a situation where the boundaries that were considered to be the unique domain of each content are blurring. In particular, it has been analyzed that it can not only fulfill its role as an independent medium but also expand the scope of DOOH advertising by combining it with transmedia storytelling enthusiasts. These results suggest the need to incorporate DOOH advertising with transmedia storytelling strategies.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.67-71
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• 2024

Mo Youzhi (1811-1871) was a famous scholar, poet and calligrapher in the late Qing Dynasty. Mo Youzhi's life was rich in experience and broad vision, especially during his ten years in the Shogunate of the Tsengoku Domain, and he made friends with many political and cultural elites. Mo Youzhi is talented and diligent, and has a good relationship with celebrities from all walks of life at that time, so that his talents have been fully demonstrated. In the Qing Dynasty, the study of calligraphy became the absolute dominant force in the world of calligraphy, and the first great prosperity occurred after the Qin and Han dynasties. In accordance with the times, Mo Youzhi devotes himself to learning, takes into account the calligraphy, and goes out on his own path. Moe's work seal, li, kai, line, especially fine seal. Based on its Lishu, this paper expounds its typical style and atypical style respectively, and also discusses the relationship between its Lishu and other fonts. Finally, the author briefly summarizes the significance of Li Shu for the creation of contemporary Li Shu.In the course of discussion, always based on calligraphy ink, consult the relevant literature, combined with Mo Youzhi's life experience, try to be objective and fair, the listed points of view can be based on.

• The Journal of the Acoustical Society of Korea
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• v.43 no.4
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• pp.466-475
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• 2024

Matched-Field Processing (MFP) is a model-based approach that requires accurate knowledge of the ocean environment and array geometry (e.g., array tilt) to localize underwater acoustic sources. Consequently, it is inherently sensitive to model mismatches. In contrast, the waveguide invariant-based approach (also known as array invariant) offers a simple and robust means for source-range estimation in shallow waters. This approach solely exploits the beam angles and travel times of multiple arrivals separated in the beam-time domain, requiring no modeling of the acoustic fields, unlike MFP. This paper extends the waveguide invariant-based approach to shallow water environments featuring a shallow pit, where the waveguide invariant is not defined due to the complex bathymetry. An in-depth performance analysis is conducted using experimental data and numerical simulations.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.675-680
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• 2024

This study aims to examine the trends in Metaverse technology following the Post-COVID era and analyze the use cases in the jewelry industry. With the endemic, the business environment for companies has shifted from online to offline, leading to a reduced public interest in the Metaverse. However, examining the global jewelry brand trends in metaverse technology reveals advancements in AR/VR technologies that enhance realism and evolve the metaverse into a space without the uncanny gap between virtual and reality. The Metaverse exhibits three main characteristics in the Post-COVID era. First, there is a transformation in the business domain, starting with digital twins. Second, it is integrating with various information and communication technologies. Third, setting a direction for Metaverse operation as an omni-channel is being emphasized. Utilizing assets learned during the COVID-19 period and continuing to learn about digital and online technologies is essential for securing market competitiveness. This paper discusses how to enhance the competitiveness of jewelry industry entities based on the trends of Metaverse technology in the Post-COVID era.