• ETRI Journal
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• v.26 no.5
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• pp.452-466
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• 2004

As the number of broadcasting channels and programs increases rapidly, the importance of personalized service has been emphasized. In this paper, we propose a practical framework of metadata broadcasting to provide personalized service according to user preferences and various terminal/network conditions. First, we present an overall system architecture of a metadata broadcasting system and then propose several core technologies (particularly in the parts of metadata authoring, metadata encoding, and metadata-based personalized content consumption). For interoperability, the proposed solution is designed to be compliant with the relevant standards of the TV-Anytime Forum, MPEG-7 Systems, and MPEG-2 Systems. Considering a home network environment, we also propose a metadata-based content adaptation scheme. Each component technology has been implemented individually, integrated into an end-to-end prototype broadcasting system, and successfully tested with a set of personalized service scenarios that are also developed in this study.

• ETRI Journal
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• v.26 no.3
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• pp.277-280
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• 2004

The distributions of electric field and induced second-order nonlinearity are analyzed in the periodic poling of optical fibers. A quasi-phase matching efficiency for the induced nonlinearity is calculated in terms of both the electrode separation distance between the applied voltage and generalized electrode width for the periodic poling. Our analysis of the quasi-phase matching efficiency implies that the conversion efficiency can be enhanced through adjusting the separation distance, and the electrode width can be maximized if the electrode width is optimized.

• ETRI Journal
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• v.26 no.3
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• pp.281-284
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• 2004

We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed-waveguide grating (AWG) on a Si substrate. A temperature-dependent wavelength shift of-0.1nm/$^{\circ}C$ in a polymeric AWG on a Si substrate is reduced of+0.1nm/$^{\circ}C$ by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.

• ETRI Journal
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• v.29 no.3
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• pp.399-401
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• 2007

With a growing emphasis on human identification, iris recognition has recently received increasing attention. Iris recognition includes eye imaging, iris segmentation, verification, and so on. In this letter, we propose a novel and efficient iris recognition method which employs a cumulative-sum-based grey change analysis. Experimental results demonstrate that the proposed method can be used for human identification in efficient manner.

• ETRI Journal
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• v.29 no.6
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• pp.811-813
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• 2007

We report on a ridge waveguide laser diode with laterally tapered waveguides fabricated in a single growing step using a double patterning method. In this structure, nearly constant output power is obtained with the change of the lower tapered waveguide width, and the facet power ratio of 1.4 to 1.5 is observed over the current range. The asymmetric facet power property is also investigated.

• ETRI Journal
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• v.25 no.4
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• pp.211-218
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• 2003

This paper presents a dynamic resource allocation algorithm with multi-frequency time-division multiple access for the return link of interactive satellite multimedia networks such as digital video broadcasting return channel via satellite systems. The proposed timeslot assignment algorithm, called the very efficient dynamic timeslot assignment (VEDTA) algorithm, gives an optimal assignment plan within a very short period. The optimality and computational efficiency of this algorithm demonstrate that it will be useful in field applications.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.12
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• pp.32-40
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• 2009

• ETRI Journal
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• v.26 no.2
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• pp.161-166
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• 2004

AC electrical properties of organic light-emitting diodes with poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV), poly[2,5-bia(dimethyloctylsilyl)-1,4-phenylenevinylene] (BDMOS-PPV), and tris-(8-hydroxyquinolate)-aluminum $(AlQ_3)$ as light-emitting materials are studied. The frequency-dependent real and imaginary parts of impedance were fitted using an equivalent circuit. We found that the conduction mechanism is a space-charge limited current with exponential trap distribution.

• ETRI Journal
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• v.26 no.2
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• pp.181-184
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• 2004

For communication between heterogeneous conference systems, it is important to build a conference control protocol independent from signaling protocols. We simulate an XML-based conference control that is under consideration as a standard mechanism. We describe the framework and operations for easy implementation in heterogeneous conference systems. The simulation results show that the proposed control protocol provides a consistent service for an increasing number of conferences and participants in small to mid-size centralized conferencing.

• ETRI Journal
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• v.27 no.6
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• pp.798-801
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• 2005

This Letter proposes a scheme that supports a fast handover effectively in hierarchical mobile IPv6 networks (F-HMIPv6) by optimizing the associated data and control flows during the handover. By NS-2 simulation, we show that the proposed scheme can give better handover performance than a simple combination of existing schemes.