• Structural Engineering and Mechanics
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• v.18 no.1
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• pp.41-58
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• 2004

The postbuckling behaviour of thin shells has fascinated researchers because the theoretical prediction and their experimental verification are often different. In reality, shell panels possess small imperfections and these can cause large reduction in static buckling strength. This is more relevant in thin laminated composite shells. To study the postbuckling behaviour of thin, imperfect laminated composite shells using finite elements, explicit incremental or secant matrices have been presented in this paper. These incremental matrices which are derived using Marguerre's shallow shell theory can be used in combination with any thin plate/shell finite element (Classical Laminated Plate Theory - CLPT) and can be easily extended to the First Order Shear deformation Theory (FOST). The advantage of the present formulation is that it involves no numerical approximation in forming total potential energy of the shell during large deformations as opposed to earlier approximate formulations published in the literature. The initial imperfection in shells could be modeled by simply adjusting the ordinate of the shell forms. The present formulation is very easy to implement in any existing finite element codes. The secant matrices presented in this paper are shown to be very accurate in tracing the postbuckling behaviour of thin isotropic and laminated composite shells with general initial imperfections.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1631-1639
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• 2018

VR 360 video contents requires new visual language research in that the viewer inevitably makes partial appreciation unlike traditional video contents. In this study, we paid attention to the fact that arrangement of events and background elements in the 360-degree extended background of VR 360 video contents will play a major role in guiding the audience. Therefore, this study focuses on the arrangement of events and background elements from a narrative point of view, and analyzed the aspects of VR 360 video contents cases.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.286-294
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• 2017

The events at the Fukushima Daiichi Nuclear Power Station in March 2011 point out, among other matters, that concurrent accidents at multiple units of a site can occur in reality. Although site risk has been deterministically considered to some extent in nuclear power plant siting and design, potential occurrence of multi-unit accident sequences at a site was not investigated in sufficient detail thus far in the nuclear power community. Therefore, there is considerable worldwide interest and research effort directed toward multi-unit site risk assessment, especially in the countries with high-density nuclear-power-plant sites such as Korea. As the technique of probabilistic safety assessment (PSA) has been successfully applied to evaluate the risk associated with operation of nuclear power plants in the past several decades, the PSA having primarily focused on single-unit risks is now being extended to the multi-unit PSA. In this paper we first characterize the site risk with explicit consideration of the risk associated with spent fuel pools as well as the reactor risks. The status of multi-unit risk assessment is discussed next, followed by a description of the emerging issues relevant to the multi-unit risk evaluation from a practical standpoint.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1461-1472
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• 2014

Recently, smart devices has been spreaded and the definition of RFID/USN(Radio Frequency Identification/Ubiquitous Sensor Network) technology has also extended. So, originally, human is an agent of communications but now, 'the things' are also an agent of communication. That is, Internet of Things(IoT). IoT is very big IT infra technology that is based on wire-wireless network technologies such as Bluetooth and Wi-Fi. However, in reality, IoT service that can provide various meaning and integrate smoothly is not appear yet. To solve these problems of IoT, we implemented Publish/Subscribe system, which operate in Zigbee based wireless sensor network by using MQTT-SN protocol. Moreover, this system can operate with combining MQTT system that is already existed in external Internet network so, extensibility and flexibility aspect is excellent. We show that possibility of IoT services that is combined between different heterogeneous network through the MQTT-SN.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.83-89
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• 2010

The reality is that existing games are commercial or violent rather than informative. So, such a phenomenon resulted in many social problems. To solve such problems, I designed and implemented a game which is not violent but educative and child-friendly. In this thesis, an educative game is defined and its characteristics are described. I designed the user interface of the game for children, proposed relevant algorithms, and showed resultant screens of the game. Also, I compared the game with the existing games in order to prove that my game is non-violent, non-commercial, and rather educative. This ladder rejection game is different from the existing game in terms of design, functions, and contents of the screen. This paper contains specific explanations about the supplemented ladder rejection game. First, the design of this ladder rejection game extended fundamental principles of the existing game and added new diverse functions.

• Journal of The Korean Association of Information Education
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• v.17 no.4
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• pp.467-474
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• 2013

This paper examined various study case about cyber network and STEAM education. We develop this STEAM career education of Cyber Network subject for 3rd and 4th graders in elementary school. We make this program by considering about student's intellectual level and interests. We offered this program to elementary 3rd and 4th graders in Jeju island step by step to evaluate the effectiveness of the developed program and teaching materials. Future work will include the follow-up and extended study. It will be expected that students will be able to develop their abilities of career exploration.

• Journal of Korean language education
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• v.29 no.1
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• pp.85-108
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• 2018

This study pointed out the reality that many novice Korean language teachers who lack rater training are scoring the learners' writing skill. The study performed and analyzed a case where pre-service teachers were educated in order to explore the possibility of promoting rater training in a Korean language teacher training course. The pre-service teachers majoring in Korean language education at the graduate school scored TOPIK compositions and were provided feedback by the FACETS program, which were further discussed at the rater meeting. In three scoring processes, the raters scored with conscious of own rating patterns and showed positive change or over correction due to excessive consciousness. Consequentially, ongoing training can improve rating ability, and considering the fact that professional rater training is hard to progress, the method composed of FACETS analysis and rater training revealed positive effects. On the other hand, the rater training including native Korean and non-native(Chinese) speakers together showed no significant difference by mother tongue but by individual difference. This can be interpreted as a positive implication to the rating reliability of non-native speakers possessing advanced Korean language abilities. However, this must be supplemented through extended research.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2237-2250
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• 2021

The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time. On the other hand, the primary concern with the extended use of analog systems is the aging effect, such as mechanical failures, environmental degradation, and obsolescence. The transition to a digital-based Man-Machine Interface Systems (MMIS) in Korea and other countries has been accelerating, but some systems are still analog-based IC systems, such as the ENFMS in APR1400 NPPs. Digitalized ENFMS can become a reality using computers and microprocessors owing to the progress in digital electronics and information technology. This paper presents the result of the first phase of the research on the digitalization of the ENFMS signal processing electronics for NPPs operated or produced in Korea. It has two main parts: (1) review engineering bases of ex-core neutron flux monitoring system, including nuclear engineering, instrumentation techniques, and analog and digital signal processing techniques, and (2) analysis of analog signal processing electronics of ENFMS for OPR1000 and APR1400 power plants. They are prerequisite to the second phase of the research which is the detailed implementation of the digitalization.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.8
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• pp.57-69
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• 2022

The purpose of the study is to empirically investigate the effect of suppliers' environmental consciousness on environmental information sharing and management performance and to conduct the mediating effect of environmental information sharing between the environmental consciousness of suppliers and environmental management performance. The scope of environmental consciousness was extended from the consumer perspective to the organizational perspective and proposed a variable called environmental information sharing to explain how environmental consciousness affects environmental management performance. The research model and hypotheses were established based on previous studies. After collecting 295 samples of effective responses from suppliers, an empirical analysis was conducted using structural equation modeling. The findings show that suppliers' environmental consciousness affects environmental information sharing and management performance, and such sharing has a mediating effect on the relationship between suppliers' environmental consciousness and environmental management performance. The fact that environmental consciousness affects environmental management performance indicates that environmental consciousness is not just a concept of values such as the firm's belief or will, but a part of the firm's actual goal of performance. Therefore, suppliers have difficulties in reality such as a lack of professional manpower or guideline, but it is necessary to enhance the importance of environmental consciousness and promote environmental information sharing.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.703-717
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• 2022

Metaverse provides a simulated environment that can produce various values while conducting economic, social, and cultural activities in a digital society where the virtual and real worlds are connected. In this paper, the direction of technological progress is predicted by analyzing the characteristics of Metaverse services and their businesses. Technologies and latest researches for the realization of the Metaverse service platform are also explored. In addition, Metaverse Ethics to construct a sustainable Metaverse and Metaverse UX to increase users' service participation are also discussed. Moreover, the R&D promotion strategy for Metaverse services are presented.