• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4398-4417
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• 2017

Multi-user Multiple-Input and Multiple-Output (MU-MIMO) has potential for prominently enhancing the capacity of wireless network by simultaneously transmitting to multiple users. User selection is an unavoidable problem which bottlenecks the gain of MU-MIMO to a great extent. Major state-of-the-art works are focusing on improving network throughput by using Channel State Information (CSI), however, the overhead of CSI feedback becomes unacceptable when the number of users is large. Some work does well in balancing tradeoff between complexity and achievable throughput but is lack of consideration of fairness. Current works universally ignore the rational utilizing of time resources, which may lead the improvements of network throughput to a standstill. In this paper, we propose TOUSE, a scalable and fair user selection scheme for MU-MIMO. The core design is dynamic-time-warping-based user selection mechanism for downlink MU-MIMO, which could make full use of concurrent transmitting time. TOUSE also presents a novel data-rate estimation method without any CSI feedback, providing supports for user selections. Simulation result shows that TOUSE significantly outperforms traditional contention-based user selection schemes in both throughput and fairness in an indoor condition.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.543-548
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• 2001

In the case of mobile internet service using WAP it was connected to http protocol using WAP Gateway, So users take increased cost of mobile internet service. And it was generated inner security problem because it watched user information in the WAP Gateway. To solve this problem we use java language Which is independant of platform and low cost and intensely security an downloadable application. Additional , Using socket connection. Wire.Wireless Messaging system(WWMS) will connect real time between PC-Client and Mobile-Client, Mobile-Client and Mobile-Client, and so on. In this paper, as design and implementation of multi-platform wire.wireless messaging use J2Me. It will be foundation do develop various mobile application in the future.

• Korean Institute of Interior Design Journal
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• v.22 no.3
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• pp.52-60
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• 2013

The contemporary concept of publicness is reinterpreted from the point of view of contemporary publicness. Contemporary perception of public space has now branched and grown into a multitude of non-traditional sites with a variety of programs in mind. In this study, the aim is to discuss how contemporary public library has been evolved as public space and how to create User-centered interaction. In the case of developed countries, the Public Libraries have showed the expected effects because they have more systematic and efficient plan. Also, these libraries are placed with each facility, not distributed separately. It promotes the accumulation of profit on the space and Increases the efficiency. They support more effectively users' activities through the linkages between each facility and create the active interaction between users. Formation of the various interactions and synergies between space had been induced. Publicity means that the state will relate a combination of a number of specific public area. In addition, open space, public place, shall be directed to: This place as one of the users in order to have meaning, must be equipped with the facilities and space to communicate and understand the local role. Methods of the study are to analyze the concept and role of the users with the concept of modern publicity, to examine the concept of multi-complexity of public libraries for the user-oriented publicness, to learn about the characteristics of public spaces in the public libraries that appear in the advanced countries, to examine how to affect these characteristics in the public libraries, and to suggest the possibility and the various application methods on the characteristics of a public space. In the end, the public libraries for the realization of the publicity, support program complexity such as education and culture, welfare facilities, and public service facilities. In the 21st century, these complexity to improve the quality of service in public libraries. These spaces can be an alternative to be kept comfortable in a more vibrant area, and can affect the social, natural, cultural, and environmental aspects of the physical environment and the objects and relationships, as well as expand.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.360-368
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• 2008

In this paper, in order that the various QoS(Qualify of Service)s that are required by different traffic class are guaranteed in the random access channels in multi-service multi-user OFDMA systems, the backoff-based random access algorithm is proposed and corresponding performance is analyzed in terms of the access success probability, the throughput, the average delay and the blocking probability. Through the numerical analysis, it is shown that the proposed backoff-based random access algorithm can provide the differentiated QoSs to random access attempts according to their service class.

• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.91-97
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• 2010

Recently, Internet users have an interest about Social Media Service in Web2.0 environment. We suggest the orchestra service as social media service to meet user satisfactions in changed web environment. We accept a concept of the MMMD (Multiple Media Multiple Devices). In other words, Internet users listen to the music not only one device but multiple devices. Each one of multiple devices can play a sound source under earmark instruments for providing users with actual feeling like an orchestra. To meet the purpose, we define 3 steps. First, we separate the sound source based on instrument information. Second, we exact the suitable sound source for play orchestra. In final step, the sound source transmits to each suitable playing device. We named the 3 step for AET process. Beside we suggest synchronization method using rest point in the MIDI file for control sound sources. Using the AET process and synchronization method we provide the orchestra service for meet user's satisfactions to users.

• Journal of Communications and Networks
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• v.10 no.3
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• pp.287-296
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• 2008

The IEEE 802.11 wireless standard uses the carrier sense multiple access with collision avoidance (CSMA/CA) as its MAC protocol (during the distributed coordination function period). This protocol is an adaptation of the CSMA/CD of the wired networks. CSMA/CA mechanism cannot guarantee quality of service (QoS) required by the application because orits random access method. In this study, we propose a new MAC protocol that considers different types of traffic (e.g., voice and data) and for each traffic type different priority levels are assigned. To improve the QoS of IEEE 802.11 MAC protocols over a multi-channel CSMA/CA, we have developed a new admission policy for both voice and data traffics. This protocol can be performed in direct sequence spread spectrum (DSSS) or frequency hopping spread spectrum (FHSS). For voice traffic we reserve a channel, while for data traffic the access is random using a CSMA/CA mechanism, and in this case a selective reject and push-out mechanism is added to meet the quality of service required by data traffic. To study the performance of the proposed protocol and to show the benefits of our design, a mathematical model is built based on Markov chains. The system could be represented by a Markov chain which is difficult to solve as the state-space is too large. This is due to the resource management and user mobility. Thus, we propose to build an aggregated Markov chain with a smaller state-space that allows performance measures to be computed easily. We have used stochastic comparisons of Markov chains to prove that the proposed access protocol (with selective reject and push-out mechanisms) gives less loss rates of high priority connections (data and voices) than the traditional one (without admission policy and selective reject and push-out mechanisms). We give numerical results to confirm mathematical proofs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1387-1394
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• 2015

Along with the development of network transmission technology, the IPTV market is growing in fast pace. Additionally the UHD resolution broadcasting system along with user experience (UX) that provides better service to user has attracted attention recently since there are not enough research has been done with differentiated the UX that can enhance the UX yet. Therefore we proposed a low complexity syntax level image stitching implementation technique that run with multi-view services, which makes possibility to view multiple channel or video contents on the screen at the same time. Simulation results have demonstrated the liability and effectiveness of the proposed algorithm by showing that capability of generating more than 80 frames per second by stitching four Full-HD size videos into UHD frame.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.3 s.8
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• pp.1-8
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• 2005

IEEE WAVE(Wireless Access in Vehicular Environment) is being developed to operate in 5 GHz DSRC band to provide cars moving at high-speed with vehicle-to-vehicle and vehicle-to-roadside communication. IEEE P 1609.3 of the WAVE protocol stack defines how multiple channels are used based on the exchange of provider-service-tables (PST) and user-service-tables (UST) for rapid link establishment and data transmission. This paper presents the design and implementation of an IEEE WAVE multi-channel transmission emulator that we have developed to study the operation of protocol and applications. Applications for a public-safety and a download service have been implemented and are shown to operate effectively on top of the emulator.

• International Journal of Knowledge Content Development & Technology
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• v.11 no.1
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• pp.85-111
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• 2021

This study aims to analyze users' assessment of electronic libraries in the mobile app market and promote service improvement based on this. To this end, the basic background and purpose of the research, research method, and research scope were first set, and the relevant literature and empirical prior studies were analyzed. Next, users' evaluations of electronic libraries were collected and analyzed from Google Play Store. Based on the results analyzed, measures to improve the quality of electronic libraries were discussed. Based on the results of the study, the following improvement measures are proposed. Need for systemic improvement and stabilization. Provision of applications suitable for multi-device environments. Resumption of services after systematic inspection after updating. Simplification of sign up, log in, and authentication procedures. User support through real-time chat. Introduction of a detailed assessment of reviews. Provision of guidance and user manual for electronic libraries. Improvements to expand user convenience, and Securing differentiation from other similar services.

• Korean journal of communication and information
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• v.46
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• pp.9-36
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• 2009

In a competitive media environment, Internet Protocol television (IPTV) has gained appeal because of its essential characteristics, 'Internet and Interactivity'. Our study aims to explore predictors that affect IPTV-VOD adoption within the context of competing media (i.e., existing multi-channel video programming services, such as cable television and digital broadcasting satellite services). In addition, this study examines if IPTV-VOD functions as a substitute for existing multi-channel services, such as cable television and direct broadcasting satellite services. A self-report survey through face-to-face interviews was conducted in Seoul metropolitan area and other six big cities. Our findings showed that primary factors for adopting an IPTV-VOD are: age of user, subjective importance of terrestial broadcasting services, real-time terrestrial broadcasting services, and other interactive service characteristics, such as time-shifting. Also, IPTV-VOD services were found to be a substitute for existing multi-channel video programming services.