• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.5
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• pp.461-474
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• 2009

The cognitive radio (CR) technique is a useful tool for improving spectrum utilization by detecting and using the vacant spectrum bands in which cooperative spectrum sensing is a key element, while avoiding interfering with the primary user. In this paper, we propose a novel cluster-based cooperative spectrum sensing scheme in cognitive radio with two solutions for the purpose of improving in sensing performance. First, for the cluster header, we use the double adaptive energy thresholds and a multi-bit quantization with different quantization interval for improving the cluster performance. Second, in the common receiver, the weighed HALF-voting rule will be applied to achieve a better combination of all cluster decisions into a global decision.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.2755-2773
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• 2015

Cooperative spectrum sensing increases the detection performance in a cognitive radio network, based on the number of sensing nodes. However, as the number of sensing nodes increases, the reporting overhead linearly increases. This paper proposes two kinds of cooperative spectrum sensing with limited reporting in a centralized cognitive radio network, a soft combination with threshold-based reporting (SC-TR) and a soft combination with contention-based reporting (SC-CR). In the proposed SC-TR scheme, each sensing node reports its sensing result to the fusion center through its own reporting channel only if the observed energy value is higher than a decision threshold. In the proposed SC-CR scheme, sensing nodes compete to report their sensing results via shared reporting channels. The simulation results show that the proposed schemes significantly reduce the reporting overhead without sacrificing the detection performance too much.

• Journal of Digital Convergence
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• v.16 no.2
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• pp.431-440
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• 2018

This study examined the effectiveness of the cognitive activity integration program to delay the progression of the mild demented elderly. The subjects were divided into experimental group and comparative group for 12 cases of mild dementia, and the cognitive activity integration program was conducted for 8 weeks and compared with the MMSE-K, ADL & IADL, CDR and GDS scales. The results show that the effectiveness and continuity of the program are as follows. First, as an implication of practical dimension, integrated program of fusion and complexity is more effective than cognitive activity program of single domain. Second, the cognitive activity integration program must be continuously provided to maintain its effectiveness. Third, the cognitive activity integration program is as important as the practice process. It is necessary to develop and disseminate a cognitive activity integration program that reflects fusion and complex treatment techniques applicable to the elderly with mild dementia by practical suggestion. Policy suggestions are needed to continue the ongoing cognitive activity integration program, to maintain effectiveness, and to delay the progress of dementia.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.711-726
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• 2013

The purpose of this study was to investigate how congruently the learning objectives of Earth Science I textbooks match the 2009 revised Earth Science curriculum. For this purpose, we classified the learning objectives of curriculum and textbooks were into three factors including ability, cross-cutting concepts, and behavioral verbs. The text data were analyzed using the semantic network analysis method. The results are as follows. The learning objectives of textbooks with regard to ability factors mainly emphasized the cognitive and affective domain. In addition, the ability of inquiry performance was emphasized in the learning objective of the curriculum. The textbooks used various sub-frame of cross-cutting concepts in comparison with the curriculum. Both textbooks and curriculum used the term 'comprehension' the most as behavioral verbs. However, most behavioral verbs just remained at the level of cognitive system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.737-743
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• 2011

Service robots are equipped with various sensors such as vision camera, sonar sensor, laser scanner, and microphones. Although these sensors have their own functions, some of them can be made to work together and perform more complicated functions. AudioFvisual fusion is a typical and powerful combination of audio and video sensors, because audio information is complementary to visual information and vice versa. Human beings also mainly depend on visual and auditory information in their daily life. In this paper, we conduct two studies using audioFvision fusion: one is on enhancing the performance of sound localization, and the other is on improving robot attention through sound localization and face detection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.19-27
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• 2014

As frequency resource has taken on greater importance, Cognitive Radio(CR) technology has been considered as the solution to improve spectrum utilization by allowing a secondary user to utilize a licensed band when the primary user is absent. So spectrum sensing is significant part of CR for high performance. Recently, cooperative spectrum sensing that secondary users share each sensing results is proposed to improve spectrum sensing accuracy. In this paper, OR rule based cooperative spectrum sensing scheme using reporting error probability which occurs in user to fusion center(FC) channel The simulation results show that proposed scheme mitigates false alarm probability limitation which appears in existing cooperative spectrum sensing scheme by restricting the number of cooperating users using reporting error probability.

• School Mathematics
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• v.10 no.2
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• pp.259-277
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• 2008

Conventional assessments only provide a single summary score that indicates the overall performance level or achievement level of a student in a single learning area. For assessments to be more effective, test should provide useful diagnostic information in addition to single overall scores. Cognitive diagnosis modeling provides useful information by estimating individual knowledge states by assessing whether an examinee has mastered specific attributes measured by the test(Embretson, 1990; DiBello, Stout, & Rousses, 1995; Tatsuoka, 1995). Attributes are skills or cognitive processes that are required to perform correctly on a particular item. By the results of this study, students, parents, and teachers would be able to see where a student stands with respect to mastering the attributes. Such information could be used to guide the learner and teacher toward areas requiring more study. By being able to assess where they stand in regard to the attributes that compose an item, students can plan a more effective learning path to be desired proficiency levels. It would be very helpful to the examinee if score reports can provide the scale scores as well as the skill profiles. While the scale scores are believed to provide students' math ability by reporting only one score point, the skill profiles can offer a skill level of strong, weak or mixed for each student for each skill.

• Journal of the Korean Society for information Management
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• v.32 no.1
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• pp.7-22
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• 2015

This paper describes a Web search optimization study that investigates both static and dynamic tuning methods for optimizing system performance. We extended the conventional fusion approach by introducing the "dynamic tuning" process with which to optimize the fusion formula that combines the contributions of diverse sources of evidence on the Web. By engaging in iterative dynamic tuning process, where we successively fine-tuned the fusion parameters based on the cognitive analysis of immediate system feedback, we were able to significantly increase the retrieval performance. Our results show that exploiting the richness of Web search environment by combining multiple sources of evidence is an effective strategy.

• Journal of Information Technology Applications and Management
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• v.23 no.2
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• pp.177-194
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• 2016

This study analyzed President Park's speeches and the government's industry policy in the field of information security using cognitive map. The relationship analysis between policy tool variables and policy goal variables was employed to derive revitalization strategy of information security. This paper found that entrepreneurship revitalization has very strong causality with expansion of domestic market and global market. But, on the other hand, HR development has very weak causality with job creation and future growth driver because the labor market in the information security industry is poor and its transfer rate to other industry is very high. This study showed that this cognitive map could be characterized by a scarcity of feedback loops and a strong emphasis on the positive loops in the structure of virtuous circle. In this paper, we also constructed a comprehensive cognitive map on the policy vision of information security, showing that there are a risk of cyber threat, an opportunity of new fusion security market, information security reinforcing circle, global economic circle, and domestic market circle.

• Journal of Internet Computing and Services
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• v.12 no.2
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• pp.1-8
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• 2011

In this paper, we propose an effective method for cooperative spectrum sensing in cognitive radios where cognitive user(CR) with the highest reliability sensing data is only selected and allowed to report its local decision to FC as only decision making node. The proposed scheme enables CR users to implicitly compare their sensing data reliabilities based on their likelihood ratio, without any collaboration among cognitive radio users. Due to the mechanism, the proposed cooperative scheme can achieves a high spectrum sensing performance while only requiring extremely low cooperation resources such as signaling overhead and cooperative time in comparison with other existing methods such as maximum ratio combination (MRC) based, equal gain combination (EGC) based and conventional hard combination based cooperative sensing methods.