• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.106-114
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• 2021

The needs in terms of wireless communications are growing up both for civil and military applications. Therefore a constant improvement of this technology is required to meet customer wishes. One of its main shortcomings is the inefficient use of the spectrum in which a large part of the allocated bands of frequencies is unused. Since communication is crucial, spectrum shortage problems can lead a multi-national and coalition operation to failure. Cognitive Radio Networks (CRNs) are a promising technology which continuously analyses the spectrum searching for available frequencies. It can solve this spectrum issue by avoiding interferences, improving system-wide spectral efficiency, robustness to dynamic conditions and allowing more spectrum flexibility This paper specifically analyzed and presented the application of the CRNs in the military operational environment, and presented the appropriate method applicable to each actual operational situation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.391-400
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• 2009

Recently, cellular communication networks are migrating from 2G to 3G. Spectrum utilization tends to be inefficient during the transition. Cognitive radio (CR) technology can be a key solution to increase spectrum efficiency by allowing secondary networks to utilize frequency resource of primary networks. However, conventional CR approaches which do not utilize the frequency reuse factor of primary networks may incur degradation of whole network performance. In this paper, we propose a mechanism that a secondary network senses pilot signals of a primary network and select optimum frequency bands. In order to maximize whole network performance, we formulate an optimization problem subject to interference constraints for a primary network and present algorithms. Simulation results compare the proposed method with the conventional method. Our proposed method shows performance gain over the conventional method if channel variation of a primary network is dynamic and the frequency reuse factor of a primary network is high.

• 한국IT서비스학회:학술대회논문집
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• 2007.05a
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• pp.477-483
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• 2007

현재 홈네트워크 산업의 부진과 문제점 현황을 정리해 보면, 이용자 입장에서는 꼭 필요한 서비스라고 느낄 수 없다는 점과 비용 대비 가치의 불만족 등 유용성의 문제점이 있으며, 소비자의 낮은 인지도와 상품 이해도의 용이성 문제를 언급할 수 있다(이희상 외, 2006). 본 연구에서는 Davis(1989)가 제안한 기술수용모델에 기반하여, 현재 홈 네트워크가 설치된 서울 시내의 아파트 주민들을 대상으로 인지된 유용성과 용이성이 홈 네트워크에 대한 사용의도에 미치는 영향을 실증적으로 분석하였다. 나아가, 홈 네트워크에 대한 사용의도가 해당 아파트의 주거가치에 대한 인식에 어떠한 영향을 미치는 지도 연구하였다. 그 결과, 인지된 용이성과 유용성은 홈 네트워크에 대한 사용의도에 정의 영향을 미쳤으며, 그 중 용이성은 유용성에 대한 선행변수로 작용함을 확인하였다. 또한, 홈 네트워크에 대한 사용의도는 해당 주거지에 대한 가치를 제고하는데 영향을 미침을 입증하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.45-49
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• 2015

In this paper, we proposed not specturm sensing but also save energy without consume energy of secondary network that spectrum sensing of cognitive applied energy harvesting scheme. Algorithms of sensing and harvesting is determine active or idle of primary network, compares the amount of energy that is harvested by energy harvesting scheme with the threshold. If secondary network to send a message and primary network is active, by changing frequency to use the spectrum. Further, if secondary network have no message, continues energy harvest. Therefore, spectrum sensing applied energy harvesting scheme, energy of secondary network is remove waste and charge energy, efficiency and utilization of cognitive network can be increase.

• Korean Journal of Legislative Studies
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• v.23 no.2
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• pp.179-217
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• 2017

The purpose of this study is to analyze the integration and separation phenomenon of the legislative network by analyzing the Legislative cosponsorship networks in the process of multicultural, family, and gender legislation. First, I analyzed the Legislative cosponsorship networks centered on the proposed bills in the Women and Family Committee. Second, Analyze the network of joint initiatives for multicultural, family, gender related legislation and representative laws in each field. In this process, we analyze who participates in the Legislative cosponsorship networks and who is the leader of the political coalition. Finally, Understand the shared characteristics and differentiated characteristics of policy networks according to policy issues.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.145-150
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• 2005

최근 전자상거래에 대한 관심과 투자가 집중되면서 효과적인 사용자 인터페이스인 대화형 에이전트에 대한 연구가 활발히 진행되고 있다. 기존의 대화형 에이전트는 사용자의 질의에 미리 준비된 답변을 제공하기 때문에 복잡한 대화 상황을 처리하지 못한다. 이런 한계를 극복하기 위해 베이지안 네트워크 등의 기법을 이용한 사용자 의도 추론 기술이 연구되고 있다. 본 논문에서는 기존의 정보검색을 위한 대화형 에이전트에서 사용자 의도 추론의 성능을 높이기 위해 노드간의 의미 관계를 표현하는 정보를 결합한 시맨틱 베이지안 네트워크(Semantic Bayesian Network; SeBN) 모델을 제안한다. 단발적인 질의 분석이 아닌 점증적 질의 분석 방법을 바탕으로 불충분한 정보로 적절한 답변을 추론하지 못할 경우에MII(mixed-initiative interaction)를 수행하여 주어진 문제를 해결한다. 실제 모바일 검색 사이트에 제안하는 방법을 적용하여 유용성을 확인하였다.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.5
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• pp.185-196
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• 2023

This paper investigates the effects of entrepreneurs' cognitive biases on business opportunity evaluation, given their strong entrepreneurial spirit, which is characterized by innovation, proactivity, and risk-taking. When making decisions related to business activities, entrepreneurs typically make rational judgments based on their knowledge, experience, and the advice of external experts. However, in situations of extreme stress or when quick decisions are required, they often rely on heuristics based on their cognitive biases. In particular, we often see cases where entrepreneurs fail because they make decisions based on heuristics in the process of evaluating and selecting new business opportunities that are planned to guarantee the growth and sustainability of their companies. This study was conducted in response to the need for research to clarify the effects of entrepreneurs' cognitive biases on new business opportunity evaluation, given that the cognitive biases of entrepreneurs, which are formed by repeated successful experiences, can sometimes lead to business failure. Although there have been many studies on the effects of cognitive biases on entrepreneurship and opportunity evaluation among university students and general people who aspire to start a business, there have been few studies that have clarified the relationship between cognitive biases and social networks among entrepreneurs. In contrast to previous studies, this study conducted empirical surveys of entrepreneurs only, and also conducted research on the relationship with social networks. For the study, a survey was conducted using a parallel survey method using online mobile surveys and self-report questionnaires from 150 entrepreneurs of small and medium-sized enterprises. The results of the study showed that 'overconfidence' and 'illusion of control', among the independent variables of entrepreneurs' cognitive biases, had a statistically significant positive(+) effect on business opportunity evaluation. In addition, it was confirmed that the moderating variable, social network, moderates the effect of overconfidence on business opportunity evaluation. This study showed that entrepreneurs' cognitive biases play a role in the process of evaluating and selecting new business opportunities, and that social networks play a role in moderating the structural relationship between entrepreneurs' cognitive biases and business opportunity evaluation. This study is expected to be of great help not only to entrepreneurs, but also to entrepreneur education and policy making, by showing how entrepreneurs can use cognitive biases in a positive way and the influence of social networks.

• The Journal of Society for e-Business Studies
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• v.18 no.1
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• pp.191-211
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• 2013

The deployment of social network service(SNS) makes the social network game(SNG) as the new value added service of SNS be popular. But, a few study had identified the reason of this popularity and the elements of SNG. Based on the social presence theory and media richness theory, we had tried to identify three community artifacts (i.e. persistent labeling, self presentation and deep profiling) and two media characteristics(i.e. vividness and interactivity) as the SNG elements in this research. Then we had empirically validated the effect of these elements on the SNGexperience (i.e. social presence, perceived enjoyment) and behavioral intentions (i.e. Continuous usage intention, willingness to pay and loyalty) of the users. We conducted a survey to the actual SNG users. 243 data were collected and analyzed by PLS algorism. The results indicated that the community artifacts mediated by the social presence and media characteristics could significantly affect on the experiences and behavioral intentions. These findings could contribute to identify what element could be the reason of social network game popularity and could also contribute to design more attractive social network game in practice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4A
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• pp.356-368
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• 2011

While most of the public radio spectrum bands are allocated to licensed users, cognitive radio has been considered as a promising technology for the efficient spectrum utilization. In this new technology, secondary users opportunistically use the temporally underutilized licensed bands as long as they do not give the harmful interference to primary users. In this paper, we focus on the infra-structured network condition in which the cognitive radio network consists of a cognitive radio base station and multiple secondary users. Upon detecting a primary user, the entire cognitive radio network generally switches to another available channel, even if most of the on-going communications still does not interfere with the primary user. Moreover, the network re-entry process on a new channel causes the service disruption of the on-going communications. For this reason, in this paper, we propose a relaying scheme for efficient frequency usage, in which the secondary user out of the interference range of a primary user performs as a relaying node for the secondary user possibly interfering with a primary user. The entire spectrum switching is not required, and thus, we can avoid the service disruption of the on-going communications as much as possible.

• Journal of Advanced Navigation Technology
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• v.13 no.2
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• pp.201-207
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• 2009

Recently effective spectrum resource technologies have been studied using a game theorectical approach for cognitive radio networks. Radio resource management is required an effective scheme because the performance of a radio communication system much depends on it's effectiveness. In this paper, we suggest a game theoretical algorithm for adaptive power control which is required an effect scheme in cognitive radio networks. It will be a distributed network. In the network distributed cognitive radio secondary users require an adaptive power control. There are many results which are suggested some possibility of game theoretical approaches for communication resource sharing. However, we suggest a practical game algorithm to achieve Nash equilibrium of all secondary users using a Nash equilibrium theorem in this paper. Particularly, a game model was analyzed for adaptive power control of a cognitive radio network, which is involved in DSSS (Direct Sequence Spread Spectrum) techniques. In case of K=63 and N=12 in the DSSS network, the number of iteration was less than maximum 200 using the suggested algorithm.