• ETRI Journal
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• v.42 no.6
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• pp.976-986
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• 2020

Internet of Things (IoT) is considered the future network to support wireless communications. To realize an IoT network, sufficient spectrum should be allocated for the rapidly increasing IoT devices. Through cognitive radio, unlicensed IoT devices exploit cooperative spectrum sensing (CSS) to opportunistically access a licensed spectrum without causing harmful interference to licensed primary users (PUs), thereby effectively improving the spectrum utilization. However, an open access cognitive IoT allows abnormal IoT devices to undermine the CSS process. Herein, we first establish a hard-combining attack model according to the malicious behavior of falsifying sensing data. Subsequently, we propose a weighted sequential hypothesis test (WSHT) to increase the PU detection accuracy and decrease the sampling number, which comprises the data transmission status-trust evaluation mechanism, sensing data availability, and sequential hypothesis test. Finally, simulation results show that when various attacks are encountered, the requirements of the WSHT are less than those of the conventional WSHT for a better detection performance.

• Journal of the Ergonomics Society of Korea
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• v.27 no.4
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• pp.15-26
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• 2008

Recently, Internet Protocol TV technology has a latent power for searching information by using internet-connected interactive TV media. It is hard to browse and search web site conveniently since the visual and input devices are not sufficient for navigating through the websites. Zoomable user interface is a possible solution that may reduce users' task load and improve their performance. In this paper, we made three types of web browsers as scroll, physical zooming and semantic zooming type. Fifteen participants asked to do searching tasks and their task time, accuracy and subjective responses are recorded. In the result, though scroll type is evaluated more efficient than other types in task time and accuracy since participants are familiar with scroll type interface, semantic zooming type is highly rated in subjective responses such as perceived searching efficiency, satisfaction and joyfulness. This result implied semantic zooming is a possible solution which is improving user experience of searching websites using Internet Protocol TV.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.95-102
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• 2019

This study was to investigate the effect of eye movement and intentional finger movement on cognitive ability. Normal adult subjects were randomly divided into two groups: saccadic eye movement(SEM) and intentional finger movement(IFM). After 2 weeks of intervention, Digit span was used for short-term memory test and N-back was used for working memory test. As a result, the short-term memory of the IFM group increased significantly over time, and the follow-up test showed difference between group. The IFM group's the execution time, the error count and the accuracy rate of n-back item showed significant effects over time. The SEM group's the execution time and the accuracy of n-back item showed significant effects over time. In conclusion, the IFM method, which is a multiple stimulus that can activate the cerebral cortex more extensively than the single stimulus SEM, may be more useful as an intervention method of cognitive function improvement.

• Korean Journal of Cognitive Science
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• v.11 no.1
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• pp.1-8
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• 2000

Most of the important visual information is presented to driver through the display panel that is related to the vehicle. If display panel is designed with the c consideration of driver's visibility, drivers can get broad visual field and visual I information related to vehicle promptly and exactly during driving situation. Therefore display panel has direct relationship with the driver's task performance and it can be considered as an important device that affects the driver-automotive interaction. Many r researches about shape, characteristic and color of display panel have been performed, but not sufficient in this country Nowadays most of vehicles has an analog type display. but its shape and arrangement a are various without any definite standards about position. Therefore. experiments using evaluation tool (VISVEC System) were conducted to inquire the driver's preference on the major objects arrangement of display panel (speedometer. tachometer. fuel meter. and t thermometer) and to ascertain the factors that have an effect on drivers according to the objects position of the display panel The experiment results showed that there was no correlation between the arrangement c characteristics preferred by subjects and the cognitive accuracy but the cognition of V visual information more easy when the each major object has its area.

• Asia Marketing Journal
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• v.14 no.2
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• pp.23-37
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• 2012

Individuals often make their judgments on the basis of the ease or difficulty with which information comes to mind (for reviews, see Greifeneder, Bless, and Pham 2010; Schwarz 1998, 2004). Recent research, however, has documented that variables known to determine the degree of cognitive resources invested in information processing such as personal relevance (Grayson and Schwarz 1999; Rothman and Schwarz 1998), accuracy motivation (Aarts and Dijksterhuis 1999), and processing capacity (Menon and Raghubir 2003) can affect the extent to which individuals draw on metacognitive difficulty in making their judgments. The primary aim of this research is thus to investigate whether individuals with substantial cognitive resources or those with lack of cognitive resources are more likely to draw on metacognitive difficulty when making their product evaluations. The findings from two laboratory experiments indicate that individuals who perceive a greater level of fit between their self-regulatory orientation and temporal construal (Experiment 1), and between their self-construal and the type of product benefit appeal (Experiment 2) are more likely than those who perceive the lack of such fit to evaluate a target product less positively after thinking of many rather than a few positive reasons. The findings provide supporting evidence for the two-stage backward inference process involved with the effect of metacognitive difficulty on consumer judgments in that consumer judgments based on metacognitive difficulty may require greater cognitive resources than those based on the content of information generated. Also, the current research documents further empirical evidence for the relationship between self-regulatory orientation-construal level fit and cognitive resources such that perceived regulatory-construal level fit can increase consumer willingness to invest cognitive resources into their judgment tasks. Last, the findings can help marketers differentiate purchase situations where asking consumers to think of many positive benefits from purchase situations where asking consumers to think of a few key benefits is relatively more beneficial.

• ETRI Journal
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• v.31 no.3
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• pp.263-270
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• 2009

This paper investigates linear soft combination schemes for cooperative spectrum sensing in cognitive radio networks. We propose two weight-setting strategies under different basic optimality criteria to improve the overall sensing performance in the network. The corresponding optimal weights are derived, which are determined by the noise power levels and the received primary user signal energies of multiple cooperative secondary users in the network. However, to obtain the instantaneous measurement of these noise power levels and primary user signal energies with high accuracy is extremely challenging. It can even be infeasible in practical implementations under a low signal-to-noise ratio regime. We therefore propose reference data matrices to scavenge the indispensable information of primary user signal energies and noise power levels for setting the proposed combining weights adaptively by keeping records of the most recent spectrum observations. Analyses and simulation results demonstrate that the proposed linear soft combination schemes outperform the conventional maximal ratio combination and equal gain combination schemes and yield significant performance improvements in spectrum sensing.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.3
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• pp.75-83
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• 2011

Cognitive radio (CR) technology is to maximize the spectrum utilization by allocating the unused spectrums to the unlicensed users. This technology enables the sharing of channels among secondary (unlicensed) and primary (licensed) users on a non-interference basis after sensing the vacant channel and as a result, it is possible to harness wireless frequency more efficiently. To enhance the accuracy of sensing, RDSS was suggested. It is a fusion mechanism based on the reputation of sensing nodes and WSPRT (weighted sequential probability ratio test). However, in RDSS, the execution number of WSPRT could increase according to the order of inputted sensing values, and the fast defense against the forged values is difficult. In this paper, we propose a transaction signing-based authentication scheme for secure distributed spectrum sensing to response the forged values. The validity of proposed scheme is provided by BAN logic.

• Asia pacific journal of information systems
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• v.28 no.1
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• pp.61-74
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• 2018

Meeting, Incentive travel, Convention, Exhibition (MICE) industries recently introduced new information systems, such as the exhibition guide system (EGS), to keep pace with Smart MICE and maximize the effect of exhibition performance. We investigate how persuasive EGS can affect the EGS acceptance of attendees via cognitive and affective response. We analyzed data from 442 EGS users at an exhibition. We found that information accuracy, information relevance, and source credibility were predictors of cognitive response. Source credibility had a significant effect on affective response. Furthermore, cognitive response was found to be a positive predictor of affective response and EGS acceptance. We also found affective response is a predictor of EGS acceptance. The theoretical and practical implications of the study were presented based on the results.

• Journal of Internet Technology
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• v.20 no.1
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• pp.301-313
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• 2019

In this paper, we propose a new MAC protocol for Cognitive Radio (CR)-based IoT networks, called MSMA/CA. We extend the standard CSMA/CA, adopted in IEEE 802.11 WLANs, to the CR networks with the minimal modification since it works well in the real world. We resolve the classical hidden/exposed terminal problems by a variant of RTS/CTS mechanism and further, the hidden primary terminal problem by the mutual spectrum sensing at the transmitter and the receiver. We also modify the backoff process of CSMA/CA to incorporate the blocking of secondary transmitters, with the aim of protecting ongoing primary transmissions from aggressive secondary users. We analyze the throughput and delay of our proposed scheme using the Markov chain model on the backoff procedure, and verify its accuracy by simulations. Simulation results demonstrate that our protocol is suitable for IoT networks since the performance is insensitive to the number of users or devices.

• The Journal of Korean Academy of Sensory Integration
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• v.21 no.2
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• pp.1-11
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• 2023

Objective : The purpose of this study was to investigate the effects of computerized cognitive rehabilitation on the attention of children with autism spectrum disorder (ASD). Methods : A multiple-baseline design was used in combination with a single-subject experimental research design. A total of 15 sessions were conducted three times a week, each lasting for 30 minutes. The maintenance and selective attention tests in the attention area of the computerized cognitive rehabilitation program were evaluated in random order after each session was completed. To evaluate the participants' selective attention, star cancellation tests was performed as pre- and post-tests. Results : After the computerized cognitive rehabilitation intervention, the accuracy of the participants' attention improved in terms of the maintenance and selective attention tests. In the analysis involving the two standard deviation bands, participants 1 and 2 showed a significant improvement, whereas participant 3 did not show a significant improvement, although the average value improved. Conclusion : The results of this study confirmed that cognitive rehabilitation involving a computerized cognitive rehabilitation program had a positive effect on the attention of three children with ASD.