• Journal of information and communication convergence engineering
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• v.8 no.5
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• pp.502-507
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• 2010

Event driven service (EDS) is one of such services administrating different functions of multiple service providers according to the user situation. This paper first describes the service model of EDS, a User-centric Service for multiple service provider environments over the next generation networks. The multiple provider environments stimulates the unified identifier management, namely unified identification (U-ID), to enable users to be provided network services without awareness of multiple providers. Combining these two concepts, i.e., EDS and U-ID, the designed structure of EDS with U-ID and related procedures are given. Finally, the implementation results tested on Korea Advanced Research Network (KOREN) are described.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1230-1239
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• 1996

This paper analyzes matched-filter acquistion performance of a direct-sequence spread-specturm multiple-access system in a Rayleigh fading channel. For an application of multiple access system, multiple access interference is considered in the performance analysis. A signal flow graph technique is used to derive mean acquisition time in terms of detection and false alarm probabilities. As aresult of performance analysis, it is shown that mean acquisition time increases as fading rate becomes faster andthe numbre of users increases, and it decreases as a matched-filter length becomes logner. The variation of parameter values hs much influence on acquisition performance as SNR/chip becomes smaller.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.4
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• pp.121-127
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• 2012

In this paper, we propose a new beamforming method which is used in Multiple User-Multiple Input Multiple Output (MU-MIMO) system. An experimental system consists of LTE based TDD base-station which has 2 MIMO elements each of which contains 10-array antennas and 2 mobile terminals each of which has a single antenna. We demonstrate that the Multiple Access Interference can further be reduced by appending a beamforming procedure in MU-MIMO system in which various users share a given channel resource. The proposed algorithm is the ordinary Lagrange beamforming algorithm combined with Zero-Forcing. It is demonstrated that the proposed beamforming method outperforms a conventional method which is the ZF at least by 8dB in terms of SNR through computer simulations. From experimental tests, we verify the feasibility of the proposed beamforming algorithm for realizing a practical LTE based TDD base-station for utilizing channel resources more efficiently.

• Korean Institute of Interior Design Journal
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• v.15 no.2 s.55
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• pp.29-36
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• 2006

This study aims to analyze the multiple meaning of color variously expressed in contemporary architecture. Nowadays heterogeneity, plurality and ephemerality of modem society have been well presented in contemporary architecture. The phenomenal characteristic of color is so appropriate to express the unfixed and immaterialized attributes of contemporary architecture that it can make color a major element of architecture, which, in the past, used to be a minor element for the lack of materiality. Through the analysis of contemporary important building projects in terms of color, it can be concluded that the architectural application of color shows multiple meanings as follows; phenomenal expression, visualization of complex programs and embodiment of design process, reflection of context and control of users' mentality. At the same time, these multiple meanings are complexly presented in a single building project.

• ETRI Journal
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• v.26 no.1
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• pp.13-20
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• 2004

We propose a new optical code division multiple access (OCDMA) scheme for reducing multiple access interference (MAI) and enhancing performance for optical subscriber access networks using modified pseudorandom noise (PN)-coded fiber Bragg gratings with bipolar OCDMA decoders. Through the bipolar OCDMA decoder and the modified PN codes, MAI among users is effectively depressed. As the data are encoded either by a unipolar signature sequence of the modified PN code or its complement according to whether the data bit is 1 or 0, the bit error ratio (BER) can be more improved with the same signal to interference plus noise ratio over the conventional on-off shift keying-based OCDMA system. We prove by numerical analysis that the BER of the proposed bipolar OCDMA system is better than the conventional unipolar OCDMA system. We also analyze the spectral power distortion effects of the broadband light source.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1447-1458
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• 2020

This paper describes a structured overlay network scheme based on multiple different time intervals. Many types of data (e.g., sensor data) can be requested at specific time intervals that depend on the user and the system. These queries are referred to as "interval queries." A method for constructing an overlay network that efficiently processes interval queries based on multiple different time intervals is proposed herein. The proposed method assumes a ring topology and assigns nodes to a keyspace based on one-dimensional time information. To reduce the number of forwarded messages for queries, each node constructs shortcut links for each interval that users tend to request. This study confirmed that the proposed method reduces the number of messages needed to process interval queries. The contributions of this study include the clarification of interval queries with specific time intervals; establishment of a structured overlay network scheme based on multiple different time intervals; and experimental verification of the scheme in terms of communication load, delay, and maintenance cost.

• Journal of Information Technology Services
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• v.14 no.1
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• pp.175-194
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• 2015

As the explosive growth of SNS users, SNS affects every aspect of our lives. Beyond the individual's scope there is a powerful influence in society. Now cyber bullying is a big problem of this society. To analyze the relationship between the SNS user features and cyber bullying phenomenon, various SNS user's personal and social characteristics were set to variables affecting the cyber bullying phenomenon on the SNS. For the research, questionnaire survey was conducted for total 200 subjects among 10~60 age band in each region across the country. We set a research model including the items that are found to be affected in cyber bullying through the prior researches. To analyze interrelation of cyber bullying phenomenon and the general characteristics of SNS users, multiple regression analysis and other analyses were conducted. As a statistical result, we found the correlation among variables and the suggestion points for a SNS platform development direction.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.41-48
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• 2012

Objective: Companies want to expand their business by providing their services at other devices and new services based upon existing services. Therefore, they look for building brand identity by providing same experience throughout devices and services. Background: Many services are available to use at multiple devices including mobile phones, tablet, personal computers, and televisions, thanks to proliferation of n-screen and cloud technology. Method: It was discussed that consistency, which emphasizes the regularity and has been one of essential aspects of user interface design, seems not effective to be applied to n-screen services, owing to different screen size, input and output peripherals, usage environment and users' attitude. Results: A new definition of same experience among different devices and services, called coherence, was introduced and abstraction levels of user interfaces were proposed as the denominator of defining coherence. Then types of users' task knowledge at each abstraction level were discussed with examples. Conclusion: This paper concluded by discussing design requirements for designing coherent user interfaces among devices and services.

• Proceedings of the IEEK Conference
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• 2001.06c
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• pp.233-236
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• 2001

When we execute a online game in the network, a lots of game informations and user informations are transfered between game server and game clients. This information has deferent data structure and communication protocol. So, game developers will be design the communication protocols and packet structures after analyze the game. And, they will be design the database for user management. It will be lots of overload to the game developers. From a user point of view, they must be register to each game server to use several games. It is a undesible operation for the game users. This problems are solved by using the communication server which operates commonly with several game servers. Game providers can get the benefit of multiple access of users and get freedom from user management. Game users can access the several games which connected to communication server by register the communication server only. In this paper we design the communication packet and propose a communication protocol which operates on the communication server described previous.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.331-343
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• 2015

We propose a distributed medium access control protocol for cognitive radio networks to opportunistically utilize multiple channels. Under the proposed protocol, cognitive radio nodes forecast and rank channel availability observing primary users' activities on the channels for a period of time by time series analyzing using smoothing models for seasonal data by Winters' method. The proposed approach protects primary users, mitigates channel access delay, and increases network performance. We analyze the optimal time to sense channels to avoid conflict with the primary users. We simulate and compare the proposed protocol with the existing protocol. The results show that the proposed approach utilizes channels more efficiently.