• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.442-449
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• 2012

Cognitive Radio(CR) is the technology that allocates the frequency by using dynamic spectrum access. We proposed a model to calculate the optimal level of the cognitive radiotelegraph, where secondary users opportunistically share the spectrum with primary users through the spectrum sensing. When secondary user with cognitive radio detects the arrival of a primary user in its current channel, the secondary user moves to the idle channel or be placed in the virtual queue. We assume that the primary users have finite buffers and the population of secondary users is finite. Using a two-dimensional Makov model with preemptive priority queueing, we could derive the blocking and waiting probability as well as the optimal level of cognitive radiotelegraph under a various range of parameter circumstances.

• The Journal of Information Systems
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• v.23 no.3
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• pp.1-23
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• 2014

Nowadays, smartphones have become a portable multimedia computer because of a variety of useful applications in our daily lives, which can be downloaded and installed easily in smartphones. Despite of the fact that, however in the IS literature there has been little research on smartphone applications' user interface design. Specifically, there has been little understanding about smartphone users' cognitive functions as a mediating variable in the relationship between the user interface design of smartphone applications and users' work performance with the applications. Thus, the research aims of this study are to examine 1) the effects of the user interface design attributes including simplicity, consistency, and metaphor on the compliance with or the extension of users' mental models representing users' cognitive functions, and 2) the effects of the users' cognitive functions on their work performance with the applications. A survey was conducted and Structural Equation Modeling(SEM) was employed to analyze the data. The results of this study showed that two of the user interface design attributes, simplicity and consistency, strongly affected users' cognitive functions. In addition, users' cognitive functions significantly influenced users' work performance. However, there was no relationship between the metaphors in the user interfaces of smartphone applications and the compliance with users' mental model. This study contributed theoretically not only to explore users' mental models that are rarely investigated in the IS field, but also to add some findings related to users' cognitive functions to the IS literature. This study also can help practitioners to develop more user friendly user interfaces of smartphone applications by suggesting the design attributes, such as simplicity, consistency, and metaphor.

• Journal of Korean Library and Information Science Society
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• v.22
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• pp.245-276
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• 1995

This study analyzed the process of information service and its factors in the cognitive viewpoint. And developed a conceptual model to help in developing future information systems and services. The results of this study were summarized as follows : 1) The paradigm of information user study is changing from the system-centered to the user-centered one. 2) The researchers describe the user's internal cognitive process as the starting point of the information service. 3) The user's personal cognitive process influence the process of the information service over. And the focus is a microscopic one including the factors of the perception and recognition of the stimulus, remembering and searching information, reasoning the rules, recognition of the patterns, formalization of the concepts, etc. 4) The information librarian performs the role as a knowledge/ information system interface, and his knowledge structure reflects the organization of that knowledge/information system. 5) The information librarians can perform their role as information specialists actively and offensively. And the performance of the librarians can be measured on the scales of the su n.0, pplying capability of relevant information and the client satisfaction.

• Asia pacific journal of information systems
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• v.16 no.1
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• pp.45-69
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• 2006

Technology Acceptance Model (TAM) has been widely used to predict user's behavior to accept the technology. Prior researches have been mainly focused on innovation constructs such as perceived usefulness and perceived ease of use. However, very little research has been conducted to understand individual mental beliefs in technology acceptance and imitation influence. This study integrates Technology Acceptance Model (TAM), Flow Theory (FT) and Diffusion of Innovation Theory (DIT). This paper indicates that imitation context, cognitive absorption (CA) based Flow theory and innovation context are the three important factors influencing user acceptance of information technologies. The proposed model has been tested among 232 users of MP3 players. Results showed that innovation context and cognitive absorption have positive influences on intention to use technology. Not all factors of the imitation context have direct effect on intention to use. However, we found that imitation context has positive influence on intention to use technology through cognitive absorption.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1549-1558
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• 2011

In this paper, we address the problem of bandwidth sharing among multiple primary users and multiple secondary users in a cognitive radio network. In cognitive radio networks, effective spectrum assignment for primary and secondary users is a challenge due to the available broad range of radio frequency spectrum as well as the requisition of harmonious coexistence of both users. To handle this problem, firstly, Bertrand game model is used to analyze a spectrum pricing in which multiple primary users emulate with each other to acquire maximal profit. After that, we employ Cournot game to model the spectrum sharing of secondary users to obtain optimal profit for each user also. Simulation results show that our scheme obtains optimal solution at Nash equilibrium.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.93-111
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• 2003

This research extends a general theory of cognition to address cognitive constraints on complex command production and allows us to make system design recommendations. The research described in this paper addresses the cognitive origins of problems user have producing sequence-dependent command strings while interacting with the UNIX operating system. We describe an empirical and theoretical analysis of user difficulties, and then show how our analyses lead to design recommendations. In addition, we summarize results from testing the impact of our design recommendations on system usability

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.529-536
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• 2010

Currently many people are awfully concerned about smart device in domestic and foreign mobile market. The need of smart device has been rapidly increased. Unlike a feature phone smart devices provide us with an intuitive interface which is easy to control. They are enable to smoothly interact between user and device. Though higher market outlook, there is a lack of empirical research on user interface in touch screen based on smart device. In this paper, we propose the touch interface conceptual model concentrating on user based on the result of previous research. Materials of this research are three kinds of smart devices which are currently released. Through expert's depth interview and observation of user, user's cognitive actions in smart device are defined. Since the method of the touch interface which is suitable for the action has been derived, we have proposed the conceptual model of user's cognitive action. This research imply to offer the excellent design guideline in order to implement touch interface to optimize user experience in touch screen based on smart device to release in the future.

• Journal of Information Processing Systems
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• v.10 no.1
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• pp.119-131
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• 2014

In recent literature on traffic scheduling, the combination of the two-dimensional discrete-time Markov chain (DTMC) and the Markov modulated Poisson process (MMPP) is used to analyze the capacity of VoIP traffic in the cognitive radio system. The performance of the cognitive radio system solely depends on the accuracy of spectrum sensing techniques, the minimization of false alarms, and the scheduling of traffic channels. In this paper, we only emphasize the scheduling of traffic channels (i.e., traffic handling techniques for the primary user [PU] and the secondary user [SU]). We consider the following three different traffic models: the cross-layer analytical model, M/G/1(m) traffic, and the IEEE 802.16e/m scheduling approach to evaluate the performance of the VoIP services of the cognitive radio system from the context of blocking probability and throughput.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.6
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• pp.90-97
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• 2012

In this paper, the new user mobility model which can be utilized to register user's location for interworking with heterogeneous overlay convergent networks under the time-varying radio propagation environment has been proposed. Thus the user mobility model is considered in order to evaluate the behaviors of users in the overlay convergent networks. This Mobile IP user mobility model will be very useful to model the user mobility behaviors and can be used to estimate the signaling traffic and frequency spectrum demands for massive data transfer for the heterogeneous overlay convergent networks.

• The Journal of Bigdata
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• v.5 no.1
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• pp.139-145
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• 2020

In the era of the 4th Industrial Revolution, the use of information based on AI APIs has a great influence on industry and life. In particular, the use of artificial intelligence data in the medical field will have many changes and effects on society. This paper is to study the necessary components to implement the "Cognitive Health Advisor model (CHA model)" and to implement the "CHA model using chatbot" based on this. It uses the open Cognitive chatbot to analyze and analyze the health status of users changing in their daily lives. The user's health information analyzed by the biometric sensor and chatbot consultation delivers the information to the user through the chatbot. And it implements a cognitive health advisor model that provides educational information for users' health promotion. Through this implementation, it intends to confirm the possibility of future use and to suggest research directions.