• Journal of Korean Society of Steel Construction
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• v.10 no.3 s.36
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• pp.451-461
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• 1998

The solution of anisotropic plate via the classical methods is limited to relatively load and boundary conditions. If these conditions are more complex, the analysis becomes increasingly tedious and even impossible. For many plate problems of considerable practical interest, analytic solutions to the governing differential equations cannot be found. Among the numerical techniques presently available, the finite difference method and the finite element method are powerful numerical methods. The objective of this paper is to compare with each numerical methods for the buckling load and modes of anisotropic composite laminated plates considering shear deformation. In applying numerical methods to solve differential equations of anisotropic plates, this study uses the finite difference method and the finite element method. In determining the eigenvalue by Finite Difference Method, this paper represent good convergence compared with Finite Element Method. Several numerical examples and buckling modes show the effectiveness of various numerical methods and they will give a guides in deciding minimum buckling load and various mode shapes.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.43-50
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• 2013

Recently, Cyber threats that is doing intelligence and sophistication from the organization's information assets to secure order technical disciplines, as well as managerial and environmental sectors, such as mind-response system is must established. In this paper, possible to analyze the case for the theory in network security, such as the logical network and physical network separation suitable for the corporate environment and constantly respond and manage the Information Security Management Model A secure network design is proposed. In particular, the proposed model improvements derived from the existing network, network improvements have been made in order to design improved ability to respond to real-time security and central manageability, security threats, pre-emptive detection and proactive coping, critical equipment in the event of a dual hwalreu through applied features such as high-availability, high-performance, high-reliability, ensuring separation of individual network security policy integrated management of individual network, network security directional.

• Journal of Power Electronics
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• v.15 no.3
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• pp.753-762
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• 2015

This paper presents a nonlinear sliding mode control (SMC) scheme with a variable damping ratio for interior permanent magnet synchronous motors (IPMSMs). First, a nonlinear sliding surface whose parameters change continuously with time is designed. Actually, the proposed SMC has the ability to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time and eliminates the singularity problem with the upper bound of an uncertain term, which cannot be measured in practice, by using a simple adaptation law. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. Moreover, a simple sliding mode observer is used to estimate the load torque and system uncertainties. The effectiveness of the proposed nonlinear SMC scheme is verified using comparative experimental results of the linear SMC scheme when the speed reference and load torque change under system uncertainties. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and less sensitivity to system uncertainties than the linear SMC method.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.747-759
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• 2013

This study posits the activities of the fandom as information behavior: information producing, information diffusion, information sharing. The authors identify the underlying motivation and needs which lead fandom to these behavior on the basis of contents theory. In particular, the manner in which the those needs influence the information behavior of fandom is explored. The data used in this study came from various Fan Caf$\acute{e}$s which are communities of star fan. The results from the survey shows that the fandom is a kind of culture closely connected to social needs. Fandom can be viewed as an important driving force in the entertainment industry as they are co-creating the value in entertainment market.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.4
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• pp.239-259
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• 2020

The importance of the composition of the editorial board member is increasing as one of the measures to improve the quality of journals and to increase its international use. In this study, the composition of the Editorial Board Member (EBM) was analyzed for the journals listed in WoS and SCOPUS among domestic journals published in the field of social sciences to derive considerations to promote the internationalization of academic journals. As a result, for the internationalization of academic journals in the social science field, the composition of EBM that can promote the convergence of theory and practice, consideration of the regional aspect for the efficiency of EBM work, the composition of the EBM considering the efficiency of English-based academic communication, participation of researchers in EBM who can connect academics and the field should be considered.

• Journal of Digital Convergence
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• v.10 no.8
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• pp.211-217
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• 2012

Conventional GrabCut algorithm is semi-automatic algorithm that user must be set rectangle window surrounds the object. This paper studied automatic object detection to solve these problem by detecting salient region based on Human Visual System. Saliency map is computed using Lab color space which is based on color opposing theory of 'red-green' and 'blue-yellow'. Then Saliency Points are computed from the boundaries of Low-Frequency region that are extracted from Saliency Map. Finally, Rectangle windows are obtained from coordinate value of Saliency Points and these windows are used in GrabCut algorithm to extract objects. Through various experiments, the proposed algorithm computing rectangle windows of salient region and extracting objects has been proved.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.437-442
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• 2018

The study aims to identify key players through the last five passes when entering shooting circles in Korea and top four countries participated in the Rio Olympics. First, the analysis code was created using the Sports code to analyze the 29 games including Korea and the top 4 countries among 33 games. Second, Ucinet 6 has been used to analyze the Closeness Centrality of each country. The results of the study show that Korea is a key player in No.13 FW, New Zealand in No.1 MF, Germany in No.5 DF, Netherlands in No.9 MF and U.K in No.8 MF. In particular, the two teams that advanced to the finals saw their proximity center index average over 60. Based on these results, it is expected that the analysis of women's field hockey matches will serve as a tool to identify key players.

• The Journal of the Convergence on Culture Technology
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• v.1 no.3
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• pp.23-30
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• 2015

Aroma therapy was used for religious or healing purpose in the world throughout the history. In these days, numbers of people use aroma therapy for various reasons such as mental health issue. Aroma diffusers are made with various subjects, but most are made with volatilization and candle by using fumigation method. Korea's a grayish-blue-powdered celadon has insignificant position in both traditional and cultural value. Grayish-blue-powdered celadon must constantly develop its style and design and collaborate with modern product to meet the demand of the today's market. In this research, it will find the method to develop an aroma diffuser by using a grayish-blue-powdered celadon to meet consumer's demand. And ultimately, this research will construct a cultural infrastructure based on traditional image and by adding more value on the traditional ceramics market.

• The Journal of Korean Association of Computer Education
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• v.20 no.6
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• pp.27-36
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• 2017

Today, a computational thinking course is being introduced in elementary, secondary and higher education curriculums. It is important to encourage a creative talent built on convergence of computational thinking and various major fields. However, proper analysis and evaluation of computational thinking assessment tools in higher education are currently not sufficient. In this study, we developed a rubric to evaluate computational thinking skills in university class from two perspectives: conceptual learning and practical programming training. Moreover, learning achievement and relevance between theory and practice were assessed. The proposed rubric is based on Computational Thinking Practices for assessing the higher education curriculum, and it is defined as a two-level structure which consists of four categories and eight items. The proposed rubric has been applied to a liberal art class in university, and the results were discussed to make future improvements.

• Atmosphere
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• v.25 no.1
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• pp.31-49
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• 2015

From the hourly data of 75 Korean weather stations over a 12-year period (2001~2012), this study has chosen three cases (January 12, 2006; January 11, 2008; and February 22, 2009) of multiple freezing rains and investigated the atmospheric circulations that seemed to cause the events. As a result, the receding high pressure type (2006), prevailing high pressure type (2008), and warm front type (2009) are confirmed as synoptic patterns. In all three cases, freezing rain was found in regions with a strong ascending current near the end point of a low-level jet that carried the warm humid air from low latitudes. The strong ascending current resulted from lower-level convergence and upper-level divergence. In 2006 and 2009, the melting process was confirmed. In 2008, the supercooled warm rain process (SWRP) was confirmed. In contrast to existing SWRP theory, it was found that the cool air produced at the middle atmosphere and near the earth's surface led to the formation of freezing rain. The sources of this cool air were supposed to be the evaporative latent heat and the cold advection coming from the northeast. On the other hand, a special case was detected, in which the freezing rain occurred when both the soil surface temperature and surface air temperature were above $0^{\circ}C$. The thickness distributions related to freezing rain in Korea were found to be similar to those in North America. A P-type nomogram was considered for freezing rain forecasting; however, it was not relevant enough to Korea, and few modifications were needed.