• Educational Technology International
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• v.6 no.2
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• pp.59-67
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• 2005

The primary purposes of this study are to develop a Situated Learning Support System based on an MMORPG (Massively Multiplayer Online Role Playing Game) and to investigate applications of Situated Learning theory both hypothetically and practically. In Situated Leaning theory, cognition is interpreted as a dynamic system related to situation, context and activity. According to this theory, learning context, social interaction and personal direct experience are also emphasized. A virtual reality learning system based on an MMORPG provides context, social interaction and a learning environment able to provide direct experiences. However, such a system has been difficult for teachers to develop. This study aims to develop a support system facilitating the construction of a Situated Learning System based on an MMORPG. This study proposes new research and practical applications of Situated Learning theory using educational games.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.347-363
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• 2024

As the number of cyberattacks against the National Critical Information Infrastructure (NCII) is steadily increasing, many countries are strengthening the protection of National Critical Information Infrastructure (NCII) through the enactment and revision of related policies and legal systems. Therefore, this paper selects countries such as the United States, the United Kingdom, Japan, Germany, and Australia, which have established National Critical Information Infrastructure (NCII) protection systems, and compares and analyzes the promotion system of each country's National Critical Information Infrastructure (NCII) protection policy. This paper compares the National Critical Information Infrastructure (NCII) protection system of each country with the cybersecurity system and analyzes the promotion structure. Based on the policy model theory, which is a modification of Allison's theory and Nakamura & Smallwood's theory, this paper analyzes the model of each country's promotion system from the perspective of policy-making and policy-execution. The United States, Japan, Germany, and Australia's policy-promotion model is a system-strengthening model in which both policy-making and policy-execution are organized around the protection of the National Critical Information Infrastructure (NCII), while the United Kingdom and South Korea's policy-promotion model is an execution-oriented model that focuses more on policy-execution.

• Information Systems Review
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• v.19 no.3
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• pp.179-199
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• 2017

As users' cross-over shopping behaviors become more popular, many studies have attempted to describe a theoretical mechanism in multichannel environments. Apart from explaining a simplified multichannel user behavior, relevant researchers must deeply understand the mechanism of users' cross-over shopping behavior, which cannot be discovered by employing either existing theories or traditional research methods. Thus, this study explores why, how, and when users conduct cross-over shopping behaviors in multichannel environments by employing a grounded theory approach. In this study, we have interviewed 25 participants who have prior experiences in cross-over shopping. By analyzing the interview manuscripts using the grounded theory approach, we have extracted 118 codes in the coding steps and ultimately presented 28 categories by incorporating similar concepts from those codes. In this qualitative grounded theory study, we have discussed why, how, and when users do cross-over shopping behavior based on our selected codes and categories as well as by listening to the stories of our interviewees. By grounding our proposed framework, which can capture both dynamic information search and purchasing behavior, this study provides an alternative research approach to explain user behavior, thereby bolstering our current understanding of the cross-over shopping behavior of users in multichannel environments.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.139-144
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• 1999

The present paper is concerned with the robust decentralized stabilization problem of large-scale systems with time delays in the interconnections using sliding mode control. Based on Lyapunov stability theorem and H$_{\infty}$ theory, an existence condition of the sliding mode and a robust decentralized sliding mode controller are newly derived for large-scale systems under mismatched uncertainties. Finally, a numerical example is given to verify the validity of the results developed in this paper.

• Proceedings of the IEEK Conference
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• summer
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• pp.213-217
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• 2004

This paper presents a method of constructing the digital logic systems(DLS) using edge-valued decision diagrams(EVDD). The proposed method is as following. The EVDD is a new data structure type of decision diagram(DD) that is recently used in constructing the digital logic systems based on the graph theory. Next, we apply EVDD to function minimization of digital logic systems. The proposed method has the visible, schematical and regular properties.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.256-259
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• 2000

A new digital redesign method which can construct a digital controller for multiple linear systems is developed. The proposed method utilized the recently developed LMI theory to obtain a single digital controller which provide good state matching properties with multiple linear systems. A numerical example is provided to evaluate the feasibility of the proposed approach.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.484-491
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• 2003

For most of linear time-varying (LTV) systems, it is difficult to design time-varying controllers in analytic way. Accordingly, by approximating LTV systems as uncertain linear time-invariant, control design approaches such as robust control have been applied to the resulting uncertain LTI systems. In particular, a robust control method such as quantitative feedback theory (QFT) has an advantage of guaranteeing the frozen-time stability and the performance specification against plant parameter uncertainties. However, if these methods are applied to the approximated linear. time-invariant (LTI) plants with large uncertainty, the resulting control law becomes complicated and also may not become ineffective with faster dynamic behavior. In this paper, as a method to enhance the fast dynamic performance of LTV systems with bounded time-varying parameters, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks.

• Science of Emotion and Sensibility
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• v.19 no.1
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• pp.11-20
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• 2016

This study was performed to examine how intrinsic acceptance for happenstance(IAH) affects evaluation of the means to achieve additional goals when the additional goals are happened to be added to the original means-goal link. Specifically, participants were asked to evaluate the effectiveness of means(e.g., exercise and saving) to achieve additional goals which are either more or less relevant to the means. The result showed that participants with high IAH were more likely to think that the original means is effective to accomplish additional goals than those with low IAH. This pattern, however, was found only when the additional goals are relevant to the means. When the relevance of the additional goals to the means was low, there was no difference in evaluation of the effectiveness of the means to achieve additional goals between participants with high and low IAH. Future research and implications of this study for goal-systems theory and intrinsic acceptance for happenstance were discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.12
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• pp.2957-2986
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• 2013

The traditional approach of fixed spectrum allocation to licensed networks has resulted in spectrum underutilisation. Cognitive radio technology is envisioned as a promising solution that can be used to resolve the ineffectiveness of the fixed spectrum allocation policy by accessing the underutilised spectrum of existing technologies opportunistically. The implementation of cognitive radio networks (CRNs) faces distinct challenges due to the fact that two systems (i.e., cognitive radio (CR) and primary users (PUs)) with conflicting interests interact with each other. Specially, in self-organised systems such as ad-hoc CRNs (AHCRNs), the coordination of spectrum access introduces challenges to researchers due to rapid utilisation changes in the available spectrum, as well as the multi-hop nature of ad-hoc networks, which creates additional challenges in the analysis of resource allocation (e.g., power control, channel and rate allocation). Instead, game theory has been adopted as a powerful mathematical tool in analysing and modelling the interaction processes of AHCRNs. In this survey, we first review the most fundamental concepts and architectures of CRNs and AHCRNs. We then introduce the concepts of game theory, utility function, Nash equilibrium and pricing techniques. Finally, we survey the recent literature on the game theoretic analysis of AHCRNs, highlighting its applicability to the physical layer PHY, the MAC layer and the network layer.

• Smart Structures and Systems
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• v.22 no.3
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• pp.303-314
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• 2018

An original quasi-3D hyperbolic shear deformation theory for simply supported functionally graded plates is proposed in this work. The theory considers both shear deformation and thickness-stretching influences by a hyperbolic distribution of all displacements within the thickness, and respects the stress-free boundary conditions on the upper and lower surfaces of the plate without using any shear correction coefficient. By expressing the shear parts of the in-plane displacements with the integral term, the number of unknowns and equations of motion of the proposed theory is reduced to four as against five in the first shear deformation theory (FSDT) and common quasi-3D theories. Equations of motion are obtained from the Hamilton principle. Analytical solutions for dynamic problems are determined for simply supported plates. Numerical results are presented to check the accuracy of the proposed theory.