• Title/Summary/Keyword: ETRi

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Impedance Spectroscopy of ${\pi}$-Conjugated Organic Materials

  • Kim, Seong-Hyun;Chu, Hye-Yong;Zyung, Taeh-Young;Yang, Yong-Suk
    • 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.

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Performance Evaluation of an XML-Based Conference Control Protocol for Centralized VoIP Conference

  • Kim, Eun-Sook;Yi, Jong-Hwa;Kang, Shin-Gak;Park, Ki-Shik
    • 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.

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A Scheme for Supporting Fast Handover in Hierarchical Mobile IPv6 Networks

  • Jung, Hee-Young;Kim, Eun-Ah;Yi, Jong-Wha;Lee, Hyeong-Ho
    • 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.

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Development of the Mobile Exchange in the CDMA Mobile System

  • Lee, Chung-Kun;Jeon, Hak-Seong;Cho, Kee-Seong;Lee, Sang-Ho
    • ETRI Journal
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    • v.19 no.3
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    • pp.169-185
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    • 1997
  • This paper presents the design concepts and the system architecture of a mobile exchange for CDMA Mobile System. The paper also discusses complex subsystems in this system and design concepts of these subsystems. To evaluate the performance of the CDMA Mobile System, we have performed a computer simulation based on the framework of the mobile exchange. Simulation results are presented in terms of network traffic load (call attempts per second) and database performance requirements (transactions per second.)

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Correlation Immune Functions with Controllable Nonlinearity

  • Chee, Seong-Taek;Lee, Sang-Jin;Kim, Kwang-Jo;Kim, Dae-Ho
    • ETRI Journal
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    • v.19 no.4
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    • pp.389-401
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    • 1997
  • In this paper, we consider the relationship between nonlinearity and correlation immunity of Boolean functions. In particular, we discuss the nonlinearity of correlation immune functions suggested by P. Camion et al. For the analysis of such functions, we present a simple method of generating the same set of functions, which makes it possible to construct correlation immune functions with controllable correlation immunity and nonlinearity. Also, we find a bound for the correlation immunity of functions having maximal nonlinearity.

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Optimal Design of Superframe Pattern for DVB-RCS Return Link

  • Lee, Ki-Dong;Cho, Yong-Hoon;Lee, Seung-Joon;Lee, Ho-Jin
    • ETRI Journal
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    • v.24 no.3
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    • pp.251-254
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    • 2002
  • We developed a method for optimal superframe design in the multi-frequency time division multiple access (MF-TDMA) return-link of a satellite multimedia interactive network called a digital video broadcasting return channel over satellite (DVB-RCS) sub-network. To find the optimal superframe pattern with the maximum data throughput, we formulated the design problem as a non-linear combinatorial optimization problem. We also devised the proposed simple method so that it would have field applicability for improving radio resource utilization in the MF-TDMA return link.

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Highly efficient and transparent white OLED for lighting

  • Lee, Jeong-Ik;Lee, Jong-Hee;Lee, Joo-Won;Shin, Jae-Heon;Chu, Hye-Yong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.482-485
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    • 2009
  • We have fabricated transparent white organic light emitting diodes (WOLEDs) for lighting application. The structure property relationship of hybrid WOLEDs has been investigated and optimized devices showed high efficiency. Introduction of transparent cathode of LiF/Al/Ag into the hybrid WOLED led highly efficient WOLED with good transparency.

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