• 한국의류학회지
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• 제39권3호
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• pp.394-407
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• 2015

Prior research highlighted personalized services as a crucial antecedent to website loyalty, yet little has been discussed on the underlying mechanism. The current study explores the intervening effects of the three psychological constructs in the personalization-loyalty relationship: cognitive efficiency, perceived enjoyment, and socialness. An experiment was conducted with a total of 414 U.S. shoppers on a fictitious e-tail site for jeans that employed different levels of personalized content. The results found that the participants exposed to the high-level personalization condition reported a higher cognitive efficiency and higher socialness perception regarding the fashion e-tail site; however, no direct effect of intensity of e-personalization was found on perceived enjoyment. Cognitive efficiency and enjoyment perceptions on the site significantly increased customers' loyalty intentions regarding the site, while website socialness perception had no direct effect on loyalty intentions. Website socialness showed indirect effects on website loyalty intentions only through cognitive efficiency and perceived enjoyment; however, no direct effect from website socialness was found. Implications and limitations of the study were discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권6호
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• pp.2873-2892
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• 2019

Reducing the interference to the licensed mobile users and obtaining the energy efficiency are key issues in cognitive heterogeneous networks. A corresponding rate loss constraint is proposed to be used for the sensing-based spectrum sharing (SBSS) model in cognitive heterogeneous networks in this paper. Resource allocation optimization strategy is designed for the maximum energy efficiency under the proposed interference constraint together with average transmission power constraint. An efficiency algorithm is studied to maximize energy efficiency due to the nonconvex optimal problem. Furthermore, the relationship between the proposed protection criterion and the conventional interference constraint strategy under imperfect sensing condition for the SBSS model is also investigated, and we found that the conventional interference threshold can be regarded as the upper bound of the maximum rate loss that the primary user could tolerate. Simulation results have shown the effectiveness of the proposed protection criterion overcome the conventional interference power constraint.

• 대한가정학회지
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• 제43권2호
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• pp.203-229
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• 2005

The purpose of this study was to explore the perceived quality of life of Korean university students'. The perceived quality of life was composed of three dimensions: emotion, cognitive efficiency, and satisfaction. The study results were as follow: 1. Korean university students felt more positive emotions when they spent time for social activities. 2. In the cognitive efficiency, social activities also scored highly of 5 questions, but in the item of "awareness of another person's eye", productive activities were higher. 3. Korean university students were more satisfied with themselves when they spent time for productive activities. However, they were more satisfied with their work itself when the work was social activities. 4. Korean university students' emotions, cognitive efficiencies, and satisfaction were significantly different by socio-graphic variables and context.

• ETRI Journal
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• 제36권3호
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• pp.506-509
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• 2014

This paper studies the energy efficiency power allocation for cognitive radio networks based on uplink orthogonal frequency-division multiplexing. The power allocation problem is intended to minimize the maximum energy efficiency measured by "Joule per bit" metric, under total power constraint and robust aggregate mutual interference power constraint. However, the above problem is non-convex. To make it solvable, an equivalent convex optimization problem is derived that can be solved by general fractional programming. Then, a robust energy efficiency power allocation scheme is presented. Simulation results corroborate the effectiveness of the proposed methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1319-1335
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• 2017

This paper proposes an opportunistic reporting-based sensing-reporting-throughput optimization scheme that maximizes the spectral efficiency of secondary users (SUs) in cooperative cognitive radio networks with a soft combining rule. The performance of cooperative spectrum sensing depends on the sensing time, the reporting time of transmitting sensing results, and the fusion scheme. While longer sensing time and reporting time improve the sensing performance, this shortens the allowable data transmission time, which in turn degrades the spectral efficiency of SUs. The proposed scheme adopts an opportunistic reporting scheme to restrain the reporting overhead and it jointly controls the sensing-reporting overhead in order to increase the spectral efficiency of SUs. We show that there is a trade-off between the spectral efficiency of SUs and the overheads of cooperative spectrum sensing. The numerical results demonstrate that the proposed scheme significantly outperforms the conventional sensing-throughput optimization schemes when there are many SUs. Moreover, the numerical results show that the sensing-reporting time should be jointly optimized in order to maximize the spectral efficiency of SUs.

• 한국통신학회논문지
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• 제32권8A호
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• pp.836-846
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• 2007

유비쿼터스 사회가 도래함에 따라 모든 사회가 무선통신과 밀접한 연관성을 가지게 되었다. 하지만 늘어나는 주파수 수요는 주파수 자원의 고갈을 야기하였다. 이와 같이 주파 주파수 자원의 중요성이 부각되어 주파수 공유 기술이 필요하게 되었다. 제안한 Cognitive UWB 시스템은 넓은 주파수 대역을 사용하는 UWB(Ultra Wideband) 기술과 채널 환경을 인지하여 사용하지 않는 비어있는 주파수 대역을 이용하는 CR(Cognitive Radio) 기술이 합해진 기술이다. 본 논문에서는 Cognitive UWB 시스템의 세부 기술을 설명하고 시뮬레이션을 통하여 원하는 마스크를 충족시키고 타 시스템의 간섭을 회피하여 성능향상을 보였다.

• 보건의료산업학회지
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• 제7권2호
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• pp.101-111
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• 2013

To develop the Korean-Version-Improvement program for ordinary people, we investigate how Korean-High-Intelligent people use their cognitive function, intellectual capacity and Intelligent Quotient test. Using Mensa iq test, we classify intelligent examination tool into various components; visual, geometrical component and cognitive interpretation component. Also we organized each component, got database of intelligent subjects sample, classified itemized availability. Based on these things, we prove efficiency of intelligent examination tool. We found out that high intelligent people showed high Intelligent Index using visual cognitive stimulation with cognitive function when subjects were exposed to certain situation; solving the problem. This intelligent examination tool is low price and safe and easily carrying out with personal computer. If we develop intelligence quotient examination customized with mental retardation populations, a variety of subjects will improve their cognition with efficiency and inexpensively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.1074-1086
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• 2015

We Relay-assisted cellular network architecture has been developed to cover cell-edge users and to improve capacity. However, the deployment of relay stations (RSs) in cellular networks may increase the total energy consumption. Though energy efficiency has become a major concern in cellular networks, little work has studied the energy efficiency of relay-assisted cellular networks by sleep scheduling. In this paper, a distributed base stations (BSs) sleep scheduling scheme in relay-assisted cellular networks is proposed. The goal is to maximize the energy efficiency under the spectral efficiency constraint. Firstly, whether the BSs should be sleeping or active is determined by the traffic profile. Then, the transmission powers of the active BSs are optimized within the game-theoretic framework, by using an interior-point method, so as to maximize the energy efficiency. Simulation results demonstrate that the effectiveness of the proposed scheme is superior to that turning on all the BSs without sleep scheduling.

• 한국콘텐츠학회논문지
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• 제20권3호
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• pp.324-335
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• 2020

본 연구는 대학생의 부모애착이 진로성숙도에 미치는 영향을 살펴보고 이들 간의 관계에서 진로결정 자기효능감과 인지적 유연성의 조절효과를 알아보고자 하였다. 이를 위해 대전·충남·서울 소재지역의 대학생들로 총 362명의 자료를 분석하였다. 연구결과, 첫째, 성별에 따라 부모애착과 진로결정 자기효능감은 유의한 차이를 보였다. 둘째, 진로결정 자기효능감은 진로성숙도에 유의한 영향을 미쳤다. 셋째, 부모애착과 진로성숙도 사이에서 진로결정 자기효능감과 인지적 유연성의 조절효과가 나타났다. 이를 통해 부모애착이 대학생의 진로성숙도에 영향을 주는 과정에서 진로결정 자기효능감과 인지적 유연성이 미치는 영향과 정도에 따라서 부모애착이 대학생의 진로성숙도 향상에 미치는 영향이 다를 수 있다는 것을 알 수 있다. 따라서 대학생이라는 그룹도 그 안에는 개인별로 서로 다른 내적 요인이 있다는 것을 인정하고 진로 결정에 도움을 줄 수 있는 다양한 프로그램 개발에 활용될 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4372-4389
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• 2019

Spectrum sensing has attracted much attention due to its significant contribution to idle spectrum detection in Cognitive Radio Networks. However, specialized discussion is on complexity-based sensing strategy for spectrum sensing seldom considered. Motivated by this, this paper is devoted to complexity-based sensing strategy for spectrum sensing. Firstly, three efficiency functions are defined to estimate sensing efficiency of a spectrum scheme. Then a novel sensing strategy is proposed given sensing performance and computational complexity. After that, the proposed sensing strategy is extended to energy detector, Cyclostationary feature detector, covariance matrix detector and cooperative spectrum detector. The proposed sensing strategy provides a novel insight into sensing performance estimation for its consideration of both sensing capacity and sensing complexity. Simulations analyze three efficiency functions and optimal sensing strategy of energy detector, Cyclostationary feature detector and covariance matrix detector.