• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.1
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• pp.21-31
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• 2013

In this study, dynamic characteristics and seismic capacity of the nuclear power plant piping system are evaluated by model test results using multi-platform shake table. The model is 21.2 m long and consists of straight pipes, elbows, and reducers. The stainless steel pipe diameters are 60.3 mm (2 in.) and 88.9 mm (3 in.) and the system was assembled in accordance with ASME code criteria. The dynamic characteristics such as natural frequency, damping and acceleration responses of the piping system were estimated using the measured acceleration, displacement and strain data. The natural frequencies of the specimen were not changed significantly before and after the testing and the failure and leakage of the piping system was not observed until the final excitation. The damping ratio was estimated in the range of 3.13 ~ 4.98 % and it is found that the allowable stress(345 MPa) according to ASME criteria is 2.5 times larger than the measured maximum stress (138 MPa) of the piping system even under the maximum excitation level of this test.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.108-113
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• 2005

The damageability and repairability of similar platform type vehicles could be very concerned with design optimization. In all the vehicles crash tested, small size passenger vehicles were weakness in aspect of damageability and repairability. The most critical area appears to be repair cost considering that parts cost is the largest portion of total repair cost segments. Besides repair cost, attaching method of front sidemember and subframe are placed special importance for impact energy absorption and damageability and repairability. So in order to improve damageability and repairability of vehicle structure and body component of the monocoque type passenger vehicles, the end of front side member and front back beam should be designed with optimum level and to supply the end of front side member as a partial condition approx 300mm. The effectiveness of design concept on the 40% offset frontal impact characteristics of the passenger vehicle structure is investigated and summarized.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.154-160
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• 2004

The purpose of this study was to evaluate airborne concentrations and characteristics of TSP, IPM, TPM and RPM in Seoul subway stations. Sampling was performed at 14 stations from April 11 to 29, 2002. Size-selective dust concentrations and metal concentrations were measured by gravimetric method and ICP-AES, respectively. The geometric mean of TSP, IPM, TPM and RPM concentrations in Seoul subway stations were 176$\mu\textrm{g}$/㎥, 348$\mu\textrm{g}$/㎥, 158$\mu\textrm{g}$/㎥ and 104$\mu\textrm{g}$/㎥, respectively. Dust concentrations in pathway were the highest and those in lobby were the lowest. The size distribution of dusts was significantly different by location of collection. When the deposition rate into pulmonary gas exchange region was estimated by size distribution, the deposition rate of dust collected from platform was higher than those of dust collected from lobby and pathway. The lower the basement levels were, the higher the deposition rates of dusts into tracheobronchial region and gas exchange region were. Copper and iron concentrations measured in platform higher were than those in other areas.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.9
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• pp.707-714
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• 2016

This paper describes analysis results of vibration characteristics and modal test for a small-scale quad-rotor drone. The rotor arm has a slender body with a propeller and motor at its tip. Rotor system generates excitation for an unbalanced mass. Therefore, the drone platform is involved in the possibility of resonance. For advance identification of the possibility of resonance, confirmation of eigen-mode being closest to the propeller operation range is necessary. Material properties of CFRP tubes used for the rotor arm were acquired by finding the natural frequency based on Rayleigh method. A simplified quad-rotor FE model consisting of rotor arm assembly with tip mass was built to perform numerical analysis, and a free-free boundary condition was applied to provide flight status. Modal tests for the actual platform with impact hammer instrument were performed to verify analysis results. Separation margin from hazardous eigen-mode was checked on the propeller operation range.

• Journal of Platform Technology
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• v.9 no.2
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• pp.10-25
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• 2021

Although many studies have been conducted on risk analysis and evaluation in the on-premises environment in information security, studies on effective methodologies of risk analysis and evaluation for cloud computing systems are lacking. In 2015, the Cloud Computing Development Act was enacted, which served as an opportunity to promote the introduction of cloud computing. However, due to the increase in security incidents in the cloud computing system, activation is insufficient. In addition, the cloud computing system is not being actively introduced because of the difficulty in understanding the cloud computing system technology of the person in charge who intends to introduce the cloud computing system. In this regard, this study presented an effective risk analysis and evaluation method by examining the characteristics, concepts, and models of cloud computing systems and analyzing how these characteristics affect risk analysis and evaluation.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.5
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• pp.741-757
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• 2021

In addition to direct sales to consumers, the direct-to-consumers (D2C) strategy, which provides specialized experiences and services, communicates closely with a consumer's perspective. This tendency is related to the recent trend wherein the luxury fashion system is being transformed into a new luxury. Therefore, this study analyzes the development of online D2C platforms and investigates the characteristics of new luxury from the functional, symbolic, and experiential dimension perspectives based on mobile apps, which is becoming increasingly important among online D2C platforms. Based on the study results, the premium of new luxury fashion displayed in Louis Vuitton's mobile D2C platform in terms of product utility and functionality is newly defined as a usable luxury experience. Moreover, from the heritage perspective, based on the cultural sympathy of the brand contents, we determine that an attachment can be formed between new luxury fashion consumers and brands. Additionally, the personalization service and experiential content on the D2C platform can directly afford emotional and bonding induced brand immersion in a playful way.

• East Asian mathematical journal
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• v.38 no.2
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• pp.187-214
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• 2022

This study compares the functions of the Learning Management Systems (LMS) in three widely used Edu-Tech platforms, that support students' individualized learning by using the learning characteristics of the students. The rapid advances in artificial intelligence (AI) are broadening their impacts in the education industry, and play a broad role in supporting student learning. In many countries, online classes have become a norm due to the COVID-19 crisis, and the demand for Edu-Tech in classes has increased rapidly. As a result, many countries, including South Korea, are now preparing and implementing various policy measures to adopt Edu-Tech in the class setting. Therefore, in this study, we analyze and compare the structures and characteristics of the three widely used Edu-Tech platforms that support individualized mathematics learning. In particular, we compare the LMSs of the three platforms by considering the elements such as learning design, learning management, learner analysis, learning result analysis, and student management functions. The results of this study give implications in the future directions to take on how to build Edu-Tech platform models that promote students' individualized mathematics learning in public education.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.39-47
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• 2022

Digital Twin is positioned as one of the establishment of a digital management system for core infrastructure in terms of collecting real data and implementing virtual space. However, there are currently no integrated three-dimensional marine information analysis tools and technologies in Korea, and unlike land, new 3D modeling technologies and data processing technologies are required to digitize flexible marine information, but there are limitations in implementation. Therefore, this study aims to present development directions in four areas: structure, data, modeling, and utilization platform of marine digital twin by analyzing trends related to marine digital twin and digital twin technology elements.

• Smart Media Journal
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• v.11 no.11
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• pp.32-39
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• 2022

As IoT applications that provide AI services increase, various hardware and software that support autonomous learning and inference are being developed. However, as the characteristics and constraints of each hardware increase difficulties in developing IoT applications, the development of an integrated platform is required. In this paper, we propose a tool for automatically generating components based on artificial neural networks and spiking neural networks as well as IoT technologies to be compatible with open platforms. The proposed component automatic generation tool supports the creation of components considering the characteristics of various hardware devices through the virtual component layer of IoT and AI and enables automatic application to open platforms.

• Fourth Industrial Review
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• v.4 no.1
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• pp.11-18
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• 2024

Purpose: The purpose of this study is to develop a geography class teaching and learning guide that enables learners to realistically explore the characteristics of the world's climate and geographical environment using digital tools. Research design, data and methodology: We review previous research on classes using goal-based scenario learning models, gamification, and digital tools, and explore tools that can be applied to world geography classes. Based on the exploration results, a goal-based scenario learning module is designed and a strategy for promoting educational gamification is established based on the ADDIE instructional design model. Results: The study comprises four sessions. Sessions 1-3 involve performance evaluations using a goal-based scenario learning module. Learners create game characters reflecting geographical characteristics, present results, and proceed with 3D modeling. In Session 4, a gamification class using Google Sites on the CoSpaces metaverse platform will be conducted. Conclusions: The study introduces a goal-based scenario learning model and a gamification class using digital tools to empower learners in exploring geographical diversity and its impact on lifestyles. Utilizing an accessible online platform, the study provides practical measures for integrating digital tools into geography education, addressing the current importance of digital technology in teaching.