• Journal of Communications and Networks
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• v.12 no.4
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• pp.366-374
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• 2010

Coded cooperation is a promising user cooperation scheme. In this paper, we first propose a novel network-coding-based coded cooperation scheme. When a user decodes its partner's information correctly in the first frame, it transmits the combination of the partner's parity bits and its own parity bits through network coding in the second frame. This is distinct from the classical scheme, where the user only transmits the partner's parity bits during cooperation. We analyze the outage probability of the proposed scheme, and show that it achieves a full diversity order. Numerical evaluations reveal that the proposed scheme outperforms the classical scheme when the inter-user channel is poor, yet is worse when the inter-user channel is strong. Also, the results show that the proposed scheme always outperforms that of no cooperation in various channel conditions while the performance of classical scheme is worse than that of no cooperation with the poor inter-user channels. This means that the performance of the proposed scheme is more stable than the classical scheme and the proposed scheme is more tolerant to the poor inter-user channels. To combine the advantages of the proposed scheme and the classical scheme under different inter-user channel conditions, we propose an adaptive solution. This adaptive scheme enhances the system performance considerably in all channel conditions in spite of the inter-user channel quality, at the expense of only one acknowledgement or non-acknowledgement bit.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.83-90
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• 2010

We describe a novel method for improving the performance of the UCC retrieval using content reputation and user reputation. The UCC retrieval is a part of the information retrieval. The goal of the information retrieval system finds documents what users want, so the goal of the UCC retrieval system tries to find UCCs themselves instead of documents. Unlike the document, the UCC has not enough textual information. Therefore, we try to use the content reputation and the user reputation based on non-textual information to gain improved retrieval performance. We evaluate content reputation using the information of the UCC itself and social activities between users related with UCCs. We evaluate user reputation using individual social activities between users or users and UCCs. We build a network with users and UCCs from social activities, and then we can get the user reputation from the network by graph algorithms. We collect the information of users and UCCs from YouTube and implement two systems using content reputation and user reputation. And then we compare two systems. From the experiment results, we can see that the system using content reputation outperforms than the system using user reputation. This result is expected to use the UCC retrieval in the feature.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.30-39
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• 2012

The essence of brand identity is to draw an interrelation between user and brand based on user's desire. The housing cultural center is focused on brand identity for satisfaction of user. The purpose of this study is to inquire out the expression characteristics of brand Identity in housing cultural center according to analyze previous studies and case studies. The results of this study are summarized as follows. 'Uniqueness' is directly expressed through brand name or logo or through brand colors. 'Experience' is expressed as auditive expression through stimulation using a body and providing music. 'Relationship' has provided a communication environment or created relationship with brand by leading interaction with others. 'Estheticism' has increased visual satisfactory level by aesthetically sublimating lighting direction or form. 'Functionality' is expressed by providing various programs through smooth flow plan and grafting with the latest technology. 'Non-dailiness' has affected memory territory by inducing curiosity and astonishment through space modification or new and contrasting direction. The housing cultural center needs to be planned as a space where interaction of user and brand will be initiatively activated sensationally and psychologically by pursuing user-oriented brand identity.

• Journal of Korea Multimedia Society
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• v.18 no.8
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• pp.960-967
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• 2015

In this paper, we propose a user interface technique based on embedded sensors applying to apps in smart phone. Especially, we implement avata generation application using image filtering technique for photo image in smart phone. In the application, The embedded sensors are used as intuitive user interface to adjust the image filtering effect for making user satisfied effect in real time after the system produced the image filtering effect for avatar. This technique provides not a simple typed method of parameter values adjustment but a new intuitively emotional adjustment method in image filtering applications. The proposed technique can use sound values from embedded mike sensor for adjusting key values of sketch filter effect if the smart phone user produces sound. Similiarly the proposed technique can use coordinate values from embedded acceleration sensor for adjusting masking values of oil painting filter effect and use brightness values from embedded light sensor for adjusting masking values of sharp filter effect. Finally, we implement image filtering application and evaluate efficiency and effectiveness for the proposed technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.12
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• pp.3037-3054
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• 2013

Interference between primary user (PU) and secondary user (SU) transceivers should be mitigated in order to implement underlay spectrum sharing in cognitive radio networks (CRN). Considering this scenario, an improved joint subcarrier and bit allocation scheme for cognitive user with primary users' cooperation (PU Coop) in CRN is proposed. In this scheme, the optimization problem is formulated to minimize the average interference power level at the PU receiver via PU Coop, which guarantees a higher primary signal to interference plus noise ratio (SINR) while maintaining the secondary user total rate constraint. The joint optimal scheme is separated into subcarrier allocation and bit assignment in each subcarrier via arith-metric geo-metric (AM-GM) inequality with asymptotical optimization solution. Moreover, the joint subcarrier and bit optimization scheme, which is evaluated by the available SU subcarriers and the allocated bits, is analyzed in the proposed PU Coop model. The performance of cognitive spectral efficiency and the average interference power level are investigated. Numerical analysis indicates that the SU's spectral efficiency increases significantly compared with the PU non-cooperation scenario. Moreover, the interference power level decreases dramatically for the proposed scheme compared with the traditional Hughes-Hartogs bit allocation scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.6034-6056
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• 2018

This paper describes two user studies in remote collaboration between two users with a video conferencing system where a remote user can draw annotations on the live video of the local user's workspace. In these two studies, the local user had the control of the view when sharing the first-person view, but our interfaces provided instant control of the shared view to the remote users. The first study investigates methods for assisting drawing annotations. The auto-freeze method, a novel solution for drawing annotations, is compared to a prior solution (manual freeze method) and a baseline (non-freeze) condition. Results show that both local and remote users preferred the auto-freeze method, which is easy to use and allows users to quickly draw annotations. The manual-freeze method supported precise drawing, but was less preferred because of the need for manual input. The second study explores visual notification for better local user awareness. We propose two designs: the red-box and both-freeze notifications, and compare these to the baseline, no notification condition. Users preferred the less obtrusive red-box notification that improved awareness of when annotations were made by remote users, and had a significantly lower level of interruption compared to the both-freeze condition.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.337-343
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• 2021

This study researched the user experience of the monthly magazine subscription service, focusing on design students and designers. The revenue of magazine industry has been declined since 2012 and some magazines stop publishing or cease to publish. That is why this studied the user experience of magazine subscription services of monthly to increase magazine sales revenue, the largest portion of whole revenue. A survey and in-depth interviews with subscribers and non-subscribers was conducted to suggest improvements for the monthly . Since this study focused on user experience of magazine subscription, it could be a future reference for studying magazine subscription service.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.454-460
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• 2021

This study attempted to empirically analyze how the use of portal news is related with user's social credibility levels. 1100 subjects were sampled and online-surveyed. The amount of news usage and level of social credibility were measured respectively by the PNRBS(Portal News Readership Behavior Score) and SCI(Social Credibility Index) which were developed by the researcher. The results show that the relationship between scocial credibility and portal new use is not a linear but some V type. In terms of the mean score of social credibility index, non-portal news user is the highest while the light user is the lowest and the heavy user is the second highest.

• Journal of Biomedical Engineering Research
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• v.45 no.2
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• pp.75-80
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• 2024

This research investigates the influence of chair tilt functionality on biometric signals and user comfort, addressing the ergonomic challenges posed by modern sedentary lifestyles. Through an experimental study involving eight male participants, the impact of chair tilt on electromyography (EMG), heart rate, metabolic rate, pressure distribution, and distance between the lumbar spine and the lumbar support part of the chair was measured across different seating postures. The study utilized chairs with both synchronous and non-synchronous tilt mechanisms to explore how adjustments in chair design affect user comfort and physiological responses during prolonged sitting. Key findings suggest that chair tilt functionality can significantly reduce muscle activity and energy expenditure, enhancing user comfort and potentially mitigating health risks associated with prolonged sedentary behavior. Notably, the study revealed a preference among participants for chairs that aligned the rotational center of the tilt with the hip joint, highlighting the importance of this ergonomic feature in enhancing user comfort. Additionally, the research proposes a novel methodology for assessing seating comfort through the analysis of both biometric and physical signals, providing valuable insights for the development of ergonomic chair designs focused on user health and comfort.

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.75-90
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• 2012

The aim of this study is to investigate the preferred website's design factors. Social computing is driving a dramatic evolution of the Web these days, and a number of users are increasing every day. But many website designers are just focusing on functional aspects of website. Also, there are few studies regarding the social computing website's emotional design. Proper designs of social computing websites could be designed through investigating the websites design factors preferred by users. Empirical study was conducted in order to investigate websites design factors preferred by users. Website design and user emotion of social computing websites were measured by the questionnaire and 254 people participated. Also, Website design and user emotion of non-social computing websites were measured by same participants, and then comparing results each other. Five design factors and eight emotion factors were derived, and only four out of design factors and three out of emotion factors were found as having significant effects on the satisfaction of social computing website. In addition, different factors in determining user satisfaction when using social computing websites and non-social computing website.