• Structural Engineering and Mechanics
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• v.91 no.1
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• pp.25-38
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• 2024

After the mainshock, whether the train can be allowed to pass the bridges plays an important role in ensuring the transport of supplies and rescue works for example, in the "12 May" earthquake in China, after evaluation, the bridge was still used for transportation in rescue at a very slow speed, engineers usually evaluate whether the train can pass the bridge safely based on the experience, lacks sufficient calculation basis and does not fully consider the risk caused by aftershocks. To address this issue, this paper comprehensively considers the randomness of track irregularity, the randomness of aftershock intensity and other multiple random sources in train-bridge interaction system (TBIS). The sensitivity of train to various random parameters after earthquake is analyzed from the perspective of probability, the most sensitive random variable in this paper is PGA of aftershocks, both for bridge and trailer car, With the increase of epicentral distance, the sensitivity of PGA will decrease, and correspondingly, for trailer car, the sensitivity of other random variables will increase, research in this paper provides a basis for the subsequent random analysis of post-earthquake driving safety.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.21-29
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• 2024

Fueled by international efforts towards AI standardization, including those by the European Commission, the United States, and international organizations, this study introduces a AI-driven framework for analyzing advancements in drone technology. Utilizing project data retrieved from the NTIS DB via the "drone" keyword, the framework employs a diverse toolkit of supervised learning methods (Keras MLP, XGboost, LightGBM, and CatBoost) enhanced by BERTopic (natural language analysis tool). This multifaceted approach ensures both comprehensive data quality evaluation and in-depth structural analysis of documents. Furthermore, a 6T-based classification method refines non-applicable data for year-on-year AI analysis, demonstrably improving accuracy as measured by accuracy metric. Utilizing AI's power, including GPT-4, this research unveils year-on-year trends in emerging keywords and employs them to generate detailed summaries, enabling efficient processing of large text datasets and offering an AI analysis system applicable to policy domains. Notably, this study not only advances methodologies aligned with AI Act standards but also lays the groundwork for responsible AI implementation through analysis of government research and development investments.

• Geomechanics and Engineering
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• v.38 no.4
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• pp.397-408
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• 2024

Buried box culverts are crucial elements of transportation infrastructure. However, their behavior under foundation loads is not well understood, indicating a significant gap in existing research. This study aims to bridge this gap by conducting a detailed numerical analysis using the Finite Element Method and Abaqus software. The research evaluates the behavior of buried box culverts by examining their interaction with surrounding soil and the pressures from surface foundation loads. Key variables such as embedment depth, culvert wall thickness, concrete material properties, foundation pressure, foundation width, soil elastic modulus, and friction angle are altered to understand their combined effects on structural response. The methodology employs a validated 2D numerical model under plane strain conditions. Parametric studies highlight the critical role of culvert depth (H) in influencing earth pressure and bending moments. Foundation pressure and width demonstrate complex interdependencies affecting culvert behavior. Variations in culvert materials' elastic modulus show minimal impact. It was found that the lower wall of the buried culvert experiences higher average pressure compared to the other two walls, due to the combined effects of the culvert's weight and down drag forces on the side walls. Furthermore, while the pressure distribution on the top and bottom walls is parabolic, the pressure on the side walls follows a different pattern, differing from that of the other two walls.

• Structural Engineering and Mechanics
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• v.91 no.5
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• pp.503-516
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• 2024

The present research examines the primary resonance (PR) behaviors of oblique stiffened multilayer functionally graded (OSMFG) shallow shells featuring an FG porous (FGP) core under an external excitation. The research considers two distinct types of FGP cores: one characterized by uniform porosity distribution (UPD) and the other by non-uniform porosity distribution (NPD) along the thickness direction. Furthermore, the study explores two types of shallow shells: one with external oblique stiffeners and one with internal oblique stiffeners, which might have angles that are similar or different from each other. Using the stress function alongside the first-order shear deformation theory (FSDT), the research establishes a nonlinear model for OSMFG shallow shells. The strain-displacement relationships are obtained utilizing FSDT and von-Kármán's geometric assumptions. The Galerkin approach is utilized to discretize the nonlinear governing equations, allowing for the analysis of stiffeners at varied angles. To validate the obtained results, a comparison is made not only with the findings of previous research but also with the response of PR obtained theoretically with the method of multiple scales, using the P-T method. Renowned for its superior accuracy and reliability, the P-T method is deemed an apt selection within this framework. Additionally, the study investigates how differences in material characteristics and stiffener angles affect the system's PR behaviors. The results of this study can be used as standards by engineers and researchers working in this area, and they can offer important information for the design and evaluation of the shell systems under consideration.

• Computers and Concrete
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• v.34 no.3
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• pp.355-365
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• 2024

TECSolverApp is an application that calculates the total equivalent seismic load (base shear) and shows the design spectra in accordance with the Turkish Earthquake Code (TEC). TECSolverApp software can present the spectral acceleration-period graph and the base shear (in terms of unit building weight) in MATLAB and .NET Core frameworks according to TEC 2007 and TEC 2018. In the software, three different building period evaluation options were provided, as entering the period directly, empirical calculation, and using the period calculation formula. In different period calculation scenarios, particular design input parameters such as site-specific spectral acceleration coefficients, local soil class, building importance coefficient, and structural system behavior coefficient are expected. TECSolverApp was produced in two different programming languages and published in MATLAB App Designer and ASP.NET Core MVC environments. To be shared in MATLAB App Designer, it was aimed at availability through the program and distributability as a desktop application. By deploying in ASP.NET Core MVC, open-source cross-platform coding and web-based accessibility were targeted. One of the strongest aspects of TECSolverApp is its developability thanks to software architecture. In this respect, it can be foreseen that other international seismic codes can be added to the calculations in the future.

• Applied Microscopy
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• v.50
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• pp.23.1-23.9
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• 2020

We propose an effective deep learning model to denoise scanning transmission electron microscopy (STEM) image series, named Noise2Atom, to map images from a source domain 𝓢 to a target domain 𝓒, where 𝓢 is for our noisy experimental dataset, and 𝓒 is for the desired clear atomic images. Noise2Atom uses two external networks to apply additional constraints from the domain knowledge. This model requires no signal prior, no noise model estimation, and no paired training images. The only assumption is that the inputs are acquired with identical experimental configurations. To evaluate the restoration performance of our model, as it is impossible to obtain ground truth for our experimental dataset, we propose consecutive structural similarity (CSS) for image quality assessment, based on the fact that the structures remain much the same as the previous frame(s) within small scan intervals. We demonstrate the superiority of our model by providing evaluation in terms of CSS and visual quality on different experimental datasets.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.582-590
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• 2020

This paper aims to analyze and introduce the primary English curriculum of North Korea reformulated according to the New Educational Program. Sources for analysis are the 4th and 5th primary school English syllabus based on the New Educational Program, explanations of the New Educational Program appeared in People's Education and Kim, Jeong-Il's selected writings. The analytical sources are classified into characteristics, objectives, contents, methods and evaluation. The findings are as follows: The primary English education aims to reach to the basis of middle school English by learning English alphabets and basic English expressions. 4th graders learn basic oral English such as pronunciation, stress and intonation for the first semester and learn English alphabets and their sounds for the second semester. 5th graders learn familiar topics in English and repeatedly practice the important components of English such as pronunciation, vocabulary and grammar. The method is to maintain students' interests in English and encourage students to use classroom English. Also, structural practice is an important part of the method. Evaluation is primarily process-oriented and must motivate students to excel in English rather than fail in English.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.71-81
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• 2016

The objective of this study is to suggest methods to improve in-home service quality through service evaluation by long-term care workers. To achieve this objective, general characteristics of 223 long-term care workers, evaluation of service and agency, and retraining needs have been surveyed. An assessment of the survey results have resulted in the following conclusions. Though long-term care workers are not uneducated, the majority face unstable employment. And the content of supervision hoped for in producing improved long-term care services has been found to be based on the service-user's relationships. Moreover, among topics needing to be addressed for retraining, much attention has been shown for understanding of the elderly and their families, health care knowledge about geriatric diseases, and counseling techniques directed towards the affected person and their family. Findings from the research are as follow: enhancing the quality of long-term care requires a structural reassessment; upgrading the quality of care agencies requires the improvement of methods used to raise awareness of users and their guardians and the expansion of opportunities for education programs for professionalism.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.535-546
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• 2010

Recently, the probability of collision accident between vehicles or vessels and infrastructures are increasing at alarming rate. Particularly, collision impact load can be detrimental to sub-structures such as piers and columns. The damaged pier from an impact load of a vehicle or a vessel can lead to member damages, which make the member more vulnerable to impact load due to other accidents which. In extreme case, may cause structural collapse. Therefore, in this study, the vehicle impact load on concrete compression member was considered to assess the quantitative design resistance capacity to improve, the existing design method and to setup the new damage assessment method. The case study was carried out using the LS-DYNA, an explicit finite element analysis program. The parameters for the case study were cross-section variation of pier, impact load angle, permanent axial load and axial load ratio, concrete strength, longitudinal and lateral rebar ratios, and slenderness ratio. Using the analysis results, the performance based resistance capacity evaluation method for impact load using satisfaction curve was developed using Bayesian probabilistic method, which can be applied to reinforced concrete column design for impact loads.

• Journal of the Korean Geosynthetics Society
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• v.11 no.3
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• pp.43-51
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• 2012

This paper describes the stability evaluation of reinforced earth wall using geosynthetic strip based on field test. The wall facing, which is applied in field, is able to present excellent scenery, and the reinforcement has improvement effect of pullout resistance based on rounded band anchor. The measurement is conducted according to construction elapsed time of structure for earth pressure, horizontal displacement of wall facing and reinforcement strain in field test. The evaluation results show that the measured earth pressure is less than theoretical earth pressure due to dispersion effect of earth pressure by geosynthetic strip. The horizontal displacement of wall facing is also satisfied a empirical criteria. The measured strain of reinforcement had nearly no effect on stability of the reinforced earth wall. Therefore, the geosynthetic strip with rounded band anchor can be applied in the reinforced earth wall, and the reinforced earth wall with geosynthetic strip can be commonly used in field because it has a structural stability.