• Proceedings of the Korean Society for Cognitive Science Conference
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• 2006.06a
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• pp.21-27
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• 2006

인과관계는 인간의 인지활동에 있어서 매우 중요한 역할을 한다. 특히 과학과 공학 분야에서 얻은 인과지식은 해당 분야를 이해하는 데에 중요한 역할을 한다. 대표적인 예로, 이들 분야 문서들의 논리적 흐름을 파악하는 데 사용 가능하다. 본 연구에서는, 정보기술 분야의 특허 문서들로부터 얻은 인과 지식을 획득하기 위하여, 문장 내에 나타나는 인과쌍들을 추출하는 방법론을 제시한다. 이를 위하여, 인과관계를 수동으로 태깅하고 관찰하는 작업을 수행하였으며, 태깅을 위한 기준을 설정하였다. 인과쌍의 추출은 패턴을 이용하여 수행하였다.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2006.06a
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• pp.95-101
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• 2006

전문용어의 용례는 일반용어의 용례와 다르게 의미를 드러내는 것이 중요하다. 또한 사전 및 시소러스와 같은 자원이 부족하다는 특징이 있다. 본 논문에서 우리는 전문용어의 용례를 벡터를 이용한 표현을 통해 더 정량적으로 나타내는 방법을 제안했다. 또한 전문용어의 자료부족 문제를 극복하기 위해 대체적 자원으로 웹을 이용하는 것을 제안했다. 실험 결과, 제안한 시스템은 기존의 시스템에 비해 최대 30%의 성능 향상을 이룰 수 있었다. 게다가 제안한 시스템에의 추출된 전문용어의 용례는 다른 자연어 처리 응용을 위한 보완적 자원으로서의 가능성을 보여줬다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2350-2364
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• 2014

This paper addresses the problem of resource allocation in amplify-and-forward (AF) relayed OFDM based cognitive radio networks (CRNs). The purpose of resource allocation is to maximize the overall throughput, while satisfying the constraints on the individual power and the interference induced to the primary users (PUs). Additionally, different from the conventional resource allocation problem, the rate-guarantee constraints of the subcarriers are considered. We formulate the problem as a mixed integer programming task and adopt the dual decomposition technique to obtain an asymptotically optimal power allocation, subcarrier pairing and relay selection. Moreover, we further design a suboptimal algorithm that sacrifices little on performance but could significantly reduce computational complexity. Numerical simulation results confirm the optimality of the proposed algorithms and demonstrate the impact of the different constraints.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.75-79
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• 2021

The article covered theoretical aspects use of information and communication technologies in teaching. Information and communication technologies are technologies that allow you to search, process and assimilate information from various sources, including the Internet. This is the presentation of information in electronic form, its processing and storage, the use of the computer, a variety of programs. The use of information and communication technologies in the work of a student gives an increase in motivation for learning; increased cognitive interest; evaluate their learning activities, identify the problems of their own educational activities; the formation of cognitive independence of students.

• Journal of Korean Elementary Science Education
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• v.28 no.2
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• pp.121-131
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• 2009

In this study, we investigated the elementary school students' perceptions toward scientific and/or technological professions in the views of accuracy, complexity, and diversity, and compared them by the students' grades and their science-related career aspiration levels. We also studied the relationships among the students' perceptions toward scientific and/or technological professions and their cognitive (science achievement), affective (enjoyment of science lessons, attitude to scientific inquiry, self-efficacy), and behavioral (participation in science-related activity) characteristics. The subjects were 369 students of 4th and 6th grades at three elementary schools in Seoul. The results revealed that the students were relatively well aware of what works and professions in science and/or technology were, but they did not have good understanding of them in the views of complexity and diversity. The 6th graders had better perceptions toward science and/or technological professions than 4th graders, although they showed the lower scores of attitude to scientific inquiry. Moreover, the higher science-related career aspirations were, the higher scores in all tests of the perceptions and the personal characteristics were. The students' perceptions toward scientific and/or technological professions were found to have relationships with their cognitive, affective, and behavioral characteristics. The multiple regression analysis of the personal characteristics on the perceptions toward scientific and/or technological professions indicated that science-related activity, science achievement, and self-efficacy were significant predictors. Educational implications are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2647-2662
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• 2014

This paper proposes an efficient and low complexity power-loading algorithm for MIMO-OFDM downlink based cognitive radio system that maximizes the sum rate of single secondary user (SU) under constraints on the tolerable interference thresholds between secondary user and primary user's frequency bands and the total transmission power. Our suboptimal algorithm is based on the $2^{nd}$ order interference tracking and nulling mechanism to allocate transmission power of the subcarriers among SU's scheme. The performance of our proposed suboptimal scheme is compared with the performance of the classical power loading algorithms, e.g., water filling, $1^{st}$ order interference tracking, nulling, and other suboptimal schemes. Numerical results show that our algorithm has low complexity but obtains a higher channel capacity than that of some previous suboptimal algorithms in some scenarios. We dedicate also that for a given interference threshold, the $2^{nd}$ order interference tracking mechanism has dynamic number of nulling position instead fixed number of nulling position.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1374-1379
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• 2016

In almost all schemes of cooperative cognitive radio networks (CCRN), the users transmit and receive signals in half-duplex mode. In this paper, a design of CCRN adopting the full-duplex (FD) technique is addressed. In order to enable FD communication among users in the CCRN, simultaneous transmitting and receiving antennas are employed for the secondary users. Preliminary results from analysis and numerical evaluation indicate that the proposed FD multiple-input-multiple-output CCRN framework can provide a performance gain over the conventional CCRN frameworks.

• Journal of The Korean Association For Science Education
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• v.33 no.3
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• pp.650-663
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• 2013

Multidimensional scaling can be used to identify relationships among concepts, revealing the structure of the cognitive framework by measuring distances within perceptual maps. The current study sought to examine the relationships among concepts related to photosynthesis in 2,844 $3^{rd}-11^{th}$ grade science students. The questionnaire included items on 'location,' 'products,' 'reactants,' and 'environmental factors', presenting images related to each theme. Students provided responses corresponding to particular topics, and reported the extent to which the concept was related to the topic on a scale from 1 to 30. The survey results were as follows: first, students were not able to clearly distinguish between or understand the four main topics. Second, students organized their cognitive structures by closely associating related concepts after learning. Third, the presented concepts revealed a mixture of scientific and non-scientific concepts, suggesting that students needed to clearly distinguish the preconceptions through which they organized concepts, so that they are suitable for cognitive structures based on learning. Furthermore, non-scientific concepts within perceptions were consistently maintained throughout learning, affecting the proximity of scientific concepts.

• Biomolecules & Therapeutics
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• v.24 no.3
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• pp.298-304
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• 2016

Dianthus superbus (D. superbus) is a traditional crude drug used for the treatment of urethritis, carbuncles and carcinomas. The objective of this study was to confirm the cognitive enhancing effect of D. superbus in memory impairment induced mice and to elucidate the possible potential mechanism. Effect of D. superbus on scopolamine induced memory impairment on mice was evaluated using the Morris water maze and passive avoidance tests. We also investigated acetylcholinesterase (AChE) activity and brain-derived neurotropic factor (BDNF) expression in scopolamine-induced mice. HPLC-DAD analysis was performed to identify active compounds in D. superbus. The results revealed that D. superbus attenuated the learning and memory impairment induced by scopolamine. D. superbus also inhibited AChE levels in the hippocampi of the scopolamine-injected mice. Moreover, D. superbus increased BDNF expression in the hippocampus. Eight compounds were identified using HPLC-DAD analysis. The content of 4-hydroxyphenyl acetic acid was higher than contents of other compounds. These results indicated that D. superbus improved memory functioning accompanied by inhibition of AChE and upregulation of BDNF, suggesting that D. superbus may be a useful therapeutic agent for the prevention or treatment of Alzheimer's disease.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.23-27
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• 2005

Humans perceptually segment events, but models that predict where events will be segmented are limited. Developing a detailed model may be hard because of the overlapping quality of events (i.e., one can smile and walk at the same time, but the endpoint of each event can be different). However, some aspects of events appear to be universally represented in the world's languages. For example, path, the trajectory of an object's movement, is one of the most universally encoded event features. Although it is generally encoded in the prepositions of English (e.g., up), in other languagesit is encoded in the verbs (e.g., descendere). Linguistic universals may represent basic levels of event perception. Here we consider how one of these, path, might be parsed. Because the spatiotemporal projection of paths to an observation point is similar to the spatial projection of objects, we tested the hypothesis that path segmentation and object segmentation would be based on similar image properties, such as discontinuities in orientation.