• 한국군사과학기술학회지
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• 제15권4호
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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.

• 한국정보시스템학회지:정보시스템연구
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• 제23권3호
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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.

• 한국도서관정보학회지
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• 제22권
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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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• 제16권1호
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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.

• 한국멀티미디어학회논문지
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• 제14권12호
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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.

• 대한인간공학회지
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• 제22권3호
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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

• 디지털콘텐츠학회 논문지
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• 제11권4호
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• pp.529-536
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• 2010

최근 국내외 모바일 시장에서 스마트 디바이스에 대한 관심과 수요가 급격히 증가하고 있다. 피쳐폰과는 달리 전면에 터치스크린을 장착한 스마트 디바이스는 직관적이고 조작이 쉬운 인터페이스를 제공하고 사용자와 기기 간의 원활한 상호작용을 가능하게 한다. 하지만 전망 높은 시장에 비해 터치스크린 기반 스마트 디바이스에서 사용자 인터페이스에 대한 실증적 연구가 부족한 실정이다. 본 연구에서는 선행 연구 결과를 토대로 사용자 중심의 터치 인터페이스 개념모델을 제안하고자 한다. 최근에 출시된 스마트 디바이스 3종을 대상으로 전문가 심층면접과 사용자 관찰 결과, 스마트 디바이스에서 사용자의 인지적 행동 요소를 정의하고, 행동 요소에 알맞은 터치 인터페이스방식을 도출하여 사용자의 인지적 행동에 대한 개념모델을 제안할 수 있었다. 이 결과를 바탕으로 향후 출시될 터치스크린 기반 스마트 디바이스에서 사용자 경험을 최대화시킬 수 있는 터치 인터페이스 구현에 좋은 디자인 지침이 될 것으로 기대한다.

• Journal of Information Processing Systems
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• 제10권1호
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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.

• 대한전자공학회논문지TC
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• 제49권6호
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• pp.90-97
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• 2012

급격한 무선구간의 트래픽 폭증으로 이종 네트워크간의 연동에 의한 Off-loading과 같은 트래픽 분산기법 등과 같은 새로운 연동방법을 매개로한 다양한 서비스와 네트워크의 융합이 가속화되면서 이종 네트워크별 효과적 이동성 관리에 대한 중요성이 부각되고 있다. 본 논문에서는 이종 네트워크 중 이동 IP 네트워크의 구조에 적합한 이동성 모델을 고려하여 주어진 환경 하에서 사용자 이동에 따른 다양한 성능평가와 관련된 지수를 도출하고 이를 활용하기 위한 방안을 제시한다. 또한 미래의 스마트 인지 네트워킹 환경 하에서는 개별 사용자의 이동성이 체계적으로 관리되어야 네트워크 자원의 효율적 활용과 무선 접속을 위한 주파수 스펙트럼의 효과적 활용에 매우 중요하다. 기존의 이동성 모델은 개별 네트워크 측면에서 다루어지면서 새로운 융합 이종 네트워크 환경에 적용하는데 적합성이 낮으므로 새로운 이동성 모델을 고려하여 융합 네트워크의 성능을 평가하는데 유용할 것으로 기대된다.

• 한국빅데이터학회지
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• 제5권1호
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• pp.139-145
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• 2020

4차산업혁명 시대에 인공지능 API에 기반한 정보의 활용은 산업과 생활에 많은 영향을 주고 있다. 특히, 의료분야에서 인공지능을 이용한 데이터 활용은 사회에 많은 변화와 영향을 미칠 것이다. 이 논문은 "Cognitive Health Advisor model(CHA model)"을 구현하기 위하여 필요한 구성요소를 연구하고, 이를 기반으로 "chatbot 이용한 CHA model"을 구현하는데 있다. 개방형 Cognitive 챗봇을 이용하여 일상 생활에서 변화되는 사용자의 건강상태를 파악하고 분석하고 생체센서와 챗봇 상담으로 분석한 사용자의 건강정보는 챗봇을 통하여 사용자에게 정보를 전달하여 사용자의 건강증진을 위한 교육정보를 제공하는 지능형 헬스 어드바이저 모델을 구현한다. 이 구현을 통하여 향후 활용 가능성을 확인하고 연구방향을 제시하고자 한다.