• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3472-3482
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• 2024

This study proposes a modified extended cognitive reliability and error analysis method (CREAM) for achieving a more accurate human error probability (HEP) in advanced control rooms. The traditional approach lacks failure data and does not consider the common performance condition (CPC) weights in different cognitive functions. The modified extended CREAM decomposes tasks using a method that combines structured information analysis (SIA) and the extended CREAM. The modified extended CREAM performs the weight analysis of CPCs in different cognitive functions, and the weights include cognitive, correlative, and important weights. We used the extended CREAM to obtain the cognitive weight. We determined the correlative weights of the CPCs for different cognitive functions using the triangular fuzzy decision-making trial and evaluation laboratory (TF-DEMATEL), and evaluated the importance weight of CPCs based on the interval 2-tuple linguistic approach and ensured the value of the importance weight using the entropy method in the different cognitive functions. Finally, we obtained the comprehensive weights of the different cognitive functions and calculated the HEPs. The accuracy and sensitivity of the modified extended CREAM were compared with those of the basic CREAM. The results demonstrate that the modified extended CREAM calculates the HEP more effectively in advanced control rooms.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.285-301
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• 2018

The purpose of this study was to investigate the relationship between health-related physical fitness factors and cognitive function and isolation on 308 elderly over 65 years old in Seoul and Gyeonggi do. The measuring instrument were as follows demographic characteristics(age, education level, drink, spouse, participation on in exercise) and health-related physical fitness(grip strength, leg strength, flexibility, balance), cognitive function (MMSE-K, digit span test) and emotional/social aspects of loneliness and isolation was measured. As a results, first, depending on the degree of demographic characteristics of elderly had significant difference. Second, health-related physical fitness and cognitive function are positive correlated, negative correlation between cognitive function and isolation. Third, health-related physical fitness of the elderly had a significant effect on cognitive function. Fourth, health-related fitness of the elderly had a significant effect on isolation. Fifth, the cognitive function of the elderly had a significant effect on isolation. In conclusion, this study will provide basic data for future aged man welfare studies and contribute to extended studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2513-2533
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• 2018

In cognitive radio technology, the overall efficiency of communications systems can be improved without allocating additional bands by allowing a secondary system to utilize the licensed band when the primary system, which has the right to use the band, does not use it. In this paper, we propose a fast and reliable common channel initialization protocol without any exchange of initialization messages between the cluster head and the member nodes in cognitive ad-hoc networks. In the proposed method, the cluster and member nodes perform channel-based spectrum sensing. After sensing, the cluster head transmits a system activation signal through its available channels with a predetermined angle difference pattern. To detect the cluster head's transmission channels and to join the cluster, each member node implements fast Fourier transform (FFT) and computes autocorrelation for the angle difference sequence of the received signal patterns. This is compared to the predetermined reference angle difference pattern. The join-request and channel-decision procedures are presented in this paper. Performance evaluation of the proposed method is presented in the simulation results.

• ETRI Journal
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• v.38 no.2
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• pp.291-301
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• 2016

In this paper, we study an optimized block-diagonal zero-forcing (BD-ZF) precoder in a two-tiered cognitive network consisting of a macro cell (MC) and a small cell (SC). By exploiting multiuser multiple-input and multiple-output Vandermonde-subspace frequency-division multiplexing (VFDM) transmission, a cognitive SC can coexist with an MC. We first devise a cross-tier precoder based on the idea of VFDM to cancel the interference from the SC to the MC. Then, we propose an optimized BD-ZF intra-tier precoder (ITP) to suppress multiuser interference and maximize the throughput in the SC. In the case where the dimension of a provided null space is larger than that required by the BD-ZF ITP, the optimized BD-ZF ITP can collect all limited channel gain by optimizing rotating and selecting matrices. Otherwise, the optimized BD-ZF ITP is validated to be equivalent to the conventional BD-ZF ITP in terms of throughput. Numerical results are presented to demonstrate the throughput improvement of the proposed optimized BD-ZF ITP and to discover the impact of imperfect channel state information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2120-2133
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• 2013

In this paper, we address the problem of linear minimum mean-squared error (MMSE) transmitter design for the cognitive radio (CR) multi-user multiple-input single-output (MU-MISO) broadcasting channel (BC), where the cognitive users are subject to not only a sum power constraint, but also a interference power constraint. Evidently, this multi-constraint problem renders it difficult to solve. To overcome this difficulty, we firstly transform it into its equivalent formulation with a single constraint. Then by utilizing BC-MAC duality, the problem of BC transmitter design can be solved by focusing on a dual MAC problem, which is easier to deal with due to its convexity property. Finally we propose an efficient two-level iterative algorithm to search the optimal solution. Our simulation results are provided to corroborate the effectiveness of the proposed algorithm and show that this proposed CR MMSE-based scheme achieves a suboptimal sum-rate performance compared to the optimal DPC-based algorithm with less computational complexity.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.619-628
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• 2012

The ZigBee network has been considered to monitor electricity usage of home appliances in the smart grid network. ZigBee, however, may suffer from a coexistence problem with wireless local area network (WLAN). In this paper, to resolve the coexistence problem between ZigBee network and WLAN, we propose a new protocol constructing a cognitive smart grid network for supporting monitoring of home appliances. In the proposed protocol, home appliances first estimates the transmission timing and channel information of WLAN by reading request to send/clear to send (RTS/CTS) frames of WLAN. Next, based on the estimated information, home appliances transmit a data at the same time as WLAN transmission. To manage the interference between WLAN and smart grid network, we propose a cognitive beamforming algorithm. The beamforming algorithm is designed to guaranteeing zero interference to WLAN while satisfying a required rate for smart metering. We also propose an energy efficient rate adaptation algorithm. By slowing down the transmission rate while satisfying an imperceptible impact of quality of service (QoS) of the receiver, the home appliance can significantly save transmit power. Numerical results show that the proposed multiple antenna technique provides reliable communications for smart metering with reduced power comparing to the simple transmission technique.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.243-246
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• 2019

In cognitive radio networks, secondary transmitters should cease its transmission immediately under the detection of primary transmission in the spectrum they are using. Then they need to exploit another idle spectrums and resynchronize to the newly found idle spectrums. Most of related work presume the existence of separate control channel used by secondary users commonly for exchanging the information of idle spectrums. However, this presumption is not feasible in real world cognitive radio scenario. Therefore we address a proactive spectrum synchronization scheme with no need of separate control channel. Our scheme lets secondary users exchange the spectrum information periodically during normal communication process and determine the next spectrum band in advance of detecting primary transmission. We evaluate our scheme in a real world cognitive radio environments set up with USRPs.

• Journal of Engineering Education Research
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• v.25 no.5
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• pp.68-74
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• 2022

The purpose of this study was to develop an infographic-based STEAM program for high school students and test its effectiveness. In this study, we converged high school 'art' education with 'Korean language' and 'mathematics.' The program was divided into four phases. The effectiveness of the program was analyzed by conducting matched pair t-test for 377 students at a girl's high school in Seoul before and after the program. The study found that the students' self-concept on mathematics and their attitude towards choosing science and engineering career showed significant increases after the program. By connecting high school courses through data visualization based on cognitive information design, findings from this study suggest that our infographic-based STEAM program should be implemented more frequently at high schools.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.27 no.1
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• pp.313-336
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• 2016

The study reviews theoretical and empirical research literature in information needs, seeking and uses in order to search for the most pertinent metatheories for studying information practices of the disadvantaged. The study examines the salient features and main theories/models of each cognitive, affective and social approach in the user-centered paradigm through analyzing prior information practices studies. While analyzing the main features of each cognitive, affective and social approach, the study points out the limitation of research using the cognitive and affective approaches to fail to theorize the relationship between individuals and complex and dynamic socio-cultural contexts in information practices. As an alternative, the study suggests using the social approach as a pertinent metatheory for understanding information practices of the disadvantaged who are entangled with myriad social contexts and issues. In order to verify the pertinence, the study examines the advantages of the social approach through analyzing both the main models related to everyday information practices under social constructionism and the main findings from information practices of the disadvantaged.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2007.05a
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• pp.157-160
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• 2007

Based on Nisbett and his colleagues' theoretical model "Holistic" and "Analytic" which show the differences in cognitive style of Eastern Asian and Westerners, the author hypothesized that the differences in cognitive style of people from diverse cultural backgrounds may influence their perception and usage of webpage. An experiment was carried out and the Eye-gaze device was used to assist to explore the relationship. The results revealed the relationship between cognitive style and webpage design. different cognitive style results different viewing pattern on webpage. Chinese people are more likely to have a holistic view of the whole page first and then focus on detail, while French people tend to read the heading information first and then proceeding down the page. Chinese emphasized the background as well as the whole look and feel of the webpage more, while French noticed the independent contents and element designs more on the webpage.