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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 27, Issue 6 - Dec 2005
Volume 27, Issue 5 - Oct 2005
Volume 27, Issue 4 - Aug 2005
Volume 27, Issue 3 - Jun 2005
Volume 27, Issue 2 - Apr 2005
Volume 27, Issue 1 - Feb 2005
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A Heuristic Buffer Management and Retransmission Control Scheme for Tree-Based Reliable Multicast
Baek, Jin-Suk ; Paris, Jehan-Francois ;
ETRI Journal, volume 27, issue 1, 2005, Pages 1~1
We propose a heuristic buffer management scheme that uses both positive and negative acknowledgments to provide scalability and reliability. Under our scheme, most receiver nodes only send negative acknowledgments to their repair nodes to request packet retransmissions while some representative nodes also send positive acknowledgments to indicate which packets can be discarded from the repair node's buffer. Our scheme provides scalability because it significantly reduces the number of feedbacks sent by the receiver nodes. In addition, it provides fast recovery of transmission errors since the packets requested from the receiver nodes are almost always available in their buffers. Our scheme also reduces the number of additional retransmissions from the original sender node or upstream repair nodes. These features satisfy the original goal of treebased protocols since most packet retransmissions are performed within a local group.
Multicast Support in DiffServ Using Mobile Agents
El Hachimi, Mohamed ; Abouaissa, Abdelhafid ; Lorenz, Pascal ;
ETRI Journal, volume 27, issue 1, 2005, Pages 13~13
Many multicast applications, such as video-on-demand and video conferencing, desire quality of service (QoS) support from an underlying network. The differentiated services (DiffServ) approach will bring benefits for theses applications. However, difficulties arise while integrating native IP multicasting with DiffServ, such as multicast group states in the core routers and a heterogeneous QoS requirement within the same multicast group. In addition, a missing per-flow reservation in DiffServ and a dynamic join/leave in the group introduce heavier and uncontrollable traffic in a network. In this paper, we propose a distributed and stateless admission control in the edge routers. We also use a mobile agents-based approach for dynamic resource availability checking. In this approach, mobile agents act in a parallel and distributed fashion and cooperate with each other in order to construct the multicast tree satisfying the QoS requirements.
Application-Level Traffic Monitoring and an Analysis on IP Networks
Kim, Myung-Sup ; Won, Young-J. ; Hong, James Won-Ki ;
ETRI Journal, volume 27, issue 1, 2005, Pages 22~22
DOI : 10.4218/etrij.05.0104.0040
Traditional traffic identification methods based on wellknown port numbers are not appropriate for the identification of new types of Internet applications. This paper proposes a new method to identify current Internet traffic, which is a preliminary but essential step toward traffic characterization. We categorized most current network-based applications into several classes according to their traffic patterns. Then, using this categorization, we developed a flow grouping method that determines the application name of traffic flows. We have incorporated our method into NG-MON, a traffic analysis system, to analyze Internet traffic between our enterprise network and the Internet, and characterized all the traffic according to their application types.
Adaptive Radio Resource Allocation for a Mobile Packet Service in Multibeam Satellite Systems
Lim, Kwang-Jae ; Kim, Soo-Young ; Lee, Ho-Jin ;
ETRI Journal, volume 27, issue 1, 2005, Pages 43~43
In this paper, we introduce an adaptive radio resource allocation for IP-based mobile satellite services. We also present a synchronous multibeam CDMA satellite system using an orthogonal resource sharing mechanism among downlink beams for the adaptive packet transmission. The simulation results, using a Ka-band mobile satellite channel and various packet scheduling schemes, show that the proposed system and resource allocation scheme improves the beam throughput by more than two times over conventional systems. The simulation results also show that, in multibeam satellite systems, a system-level adaptation to a user's channel and interference conditions according to user locations and current packet traffic is more efficient in terms of throughput improvement than a user-level adaptation.
High-Performance Spatial and Temporal Error-Concealment Algorithms for Block-Based Video Coding Techniques
Hsu, Ching-Ting ; Chen, Mei-Juan ; Liao, Wen-Wei ; Lo, Shen-Yi ;
ETRI Journal, volume 27, issue 1, 2005, Pages 53~53
A compressed video bitstream is sensitive to errors that may severely degrade the reconstructed images even when the bit error rate is small. One approach to combat the impact of such errors is the use of error concealment at the decoder without increasing the bit rate or changing the encoder. For spatial-error concealment, we propose a method featuring edge continuity and texture preservation as well as low computation to reconstruct more visually acceptable images. Aiming at temporal error concealment, we propose a two-step algorithm based on block matching principles in which the assumption of smooth and uniform motion for some adjacent blocks is adopted. As simulation results show, the proposed spatial and temporal methods provide better reconstruction quality for damaged images than other methods.
Evaluating Internet Pricing Schemes: A Three-Dimensional Visual Model
Nguyen, Thuy T.T. ; Armitage, Grenville J. ;
ETRI Journal, volume 27, issue 1, 2005, Pages 64~64
Traditional Internet pricing schemes are coming under continual pressure to adapt to, and encourage, a changing mix of Internet applications and consumer usage patterns. Much research effort over the last decade has been focused on developing more efficient and attractive charging schemes. However, none of the proposed models has been widely deployed. This raises questions regarding the inhibiting factors and missing pieces that make pricing the Internet such a challenge. In this paper, we discuss the problems with current Internet pricing schemes, review the history of Internet pricing research over the last ten years, and summarize the key features and motivations of the most significant models. We develop a novel visual approach to comparing and evaluating such schemes using a three-dimensional (3D) metric encompassing technical efficiency, economic efficiency, and social impact. We address and discuss the important factors that have inhibited the deployment of the reviewed models and suggest productive areas of focus for future Internet pricing research.
An X-Band Carbon-Doped InGaP/GaAs Heterojunction Bipolar Transistor MMIC Oscillator
Kim, Young-Gi ; Kim, Chang-Woo ; Kim, Seong-Il ; Min, Byoung-Gue ; Lee, Jong-Min ; Lee, Kyung-Ho ;
ETRI Journal, volume 27, issue 1, 2005, Pages 75~75
This paper addresses a fully-integrated low phase noise X-band oscillator fabricated using a carbon-doped InGaP heterojunction bipolar transistor (HBT) GaAs process with a cutoff frequency of 53.2 GHz and maximum oscillation frequency of 70 GHz. The oscillator circuit consists of a negative resistance generating circuit with a base inductor, a resonating emitter circuit with a microstrip line, and a buffering resistive collector circuit with a tuning diode. The oscillator exhibits 4.33 dBm output power and achieves -127.8 dBc/Hz phase noise at 100 kHz away from a 10.39 GHz oscillating frequency, which benchmarks the lowest reported phase noise achieved for a monolithic X-band oscillator. The oscillator draws a 36 mA current from a 6.19 V supply with 47.1 MHz of frequency tuning range using a 4 V change. It occupies a
Voltage-Mode 1.5 Gbps Interface Circuits for Chip-to-Chip Communication
Lee, Kwang-Jin ; Kim, Tae-Hyoung ; Cho, Uk-Rae ; Byun, Hyun-Geun ; Kim, Su-Ki ;
ETRI Journal, volume 27, issue 1, 2005, Pages 81~81
In this paper, interface circuits that are suitable for point-to-point interconnection with an over 1 Gbps data rate per pin are proposed. To achieve a successful data transfer rate of multi-gigabits per-second between two chips with a point-to-point interconnection, the input receiver uses an on-chip parallel terminator of the pass gate style, while the output driver uses the pullup and pulldown transistors of the diode-connected style. In addition, the novel dynamic voltage level converter (DVLC) has solved such problems as the access time increase and valid data window reduction. These schemes were adopted on a 64 Mb DDR SRAM with a 1.5 Gbps data rate per pin and fabricated using a 0.10
dual gate oxide CMOS technology.
Low-Loss Compact Arrayed Waveguide Grating with Spot-Size Converter Fabricated by a Shadow-Mask Etching Technique
Jeong, Geon ; Kim, Dong-Hoon ; Choi, Jun-Seok ; Lee, Dong-Hwan ; Park, Mahn-Yong ; Kim, Jin-Bong ; Lee, Hyung-Jong ; Lee, Hyun-Yong ;
ETRI Journal, volume 27, issue 1, 2005, Pages 89~89
This paper describes a low-loss, compact, 40-channel arrayed waveguide grating (AWG) which utilizes a monolithically integrated spot-size converter (SSC) for lowering the coupling loss between silica waveguides and standard single-mode fibers. The SSC is a simple waveguide structure that is tapered in both the vertical and horizontal directions. The vertically tapered structure was realized using a shadow-mask etching technique. By employing this technique, the fabricated, 40-channel, 100 GHz-spaced AWG with silica waveguides of 1.5% relative index-contrast showed an insertion-loss figure of 2.8 dB without degrading other optical performance.
Waveguiding Effect in Electroabsorption Modulators: Passivation Layers and Their Impact on Extinction Ratios
Shin, Dong-Soo ;
ETRI Journal, volume 27, issue 1, 2005, Pages 95~95
Waveguide structures of the stand-alone electroabsorption (EA) modulator and the electroabsorption modulated laser (EML) are investigated using the 3D beam propagation method. The EA waveguide structures with InP-based passivation layers show saturation in the extinction ratio (ER) due to the stray light traveling through the passivation layers. This paper demonstrates that narrower passivation layers suppress stray-light excitation in the EA waveguide, increasing the ER. A taper structure in the isolation section of the EML waveguide can reduce the mode mismatch and suppress the excitation of the stray light, increasing the ER further. Low-index-polymer passivation layers can confine the mode more tightly in the active waveguide, yielding an even higher ER.
Remultiplexing of Ensemble Transport Interface for Terrestrial DMB Service
Yun, Joung-Il ; Bae, Byung-Jun ; Hahm, Young-Kwon ; Ahn, Byung-Ha ;
ETRI Journal, volume 27, issue 1, 2005, Pages 102~102
In this letter, we present a layered structure of the Korean terrestrial Digital Multimedia Broadcasting (TDMB) transmission system for multimedia broadcasting service and introduce a device called the Ensemble Remultiplexer which is designed to remultiplex the Ensemble Transport Interface (ETI) for T-DMB service. This letter describes the remultiplexing process of the Ensemble Remultiplexer.
A Gateway and Framework for Telematics Systems Independent on Mobile Networks
Han, Woo-Yong ; Kwon, Oh-Cheon ; Park, Jong-Hyun ; Kang, Ji-Hoon ;
ETRI Journal, volume 27, issue 1, 2005, Pages 106~106
In this letter, we analyze the problems with the existing telematics service systems that have been dependently developed and provided on a specific mobile network infrastructure. Then, we suggest methods to solve the problems and propose an architecture of the gateway and framework to implement our methods. We also verify the effectiveness of the suggested architecture through a comparison with an existing telematics system. With this architecture, it is possible to develop service applications without knowledge of the underlying mobile network technology and the system integration methods.
Efficient Load Balancing Algorithms for a Resilient Packet Ring
Cho, Kwang-Soo ; Joo, Un-Gi ; Lee, Heyung-Sub ; Kim, Bong-Tae ; Lee, Won-Don ;
ETRI Journal, volume 27, issue 1, 2005, Pages 110~110
The resilient packet ring (RPR) is a data optimized ring network, where one of the key issues is on load balancing for competing streams of elastic traffic. This paper suggests three efficient traffic loading algorithms on the RPR. For the algorithms, we evaluate their efficiency via analysis or simulation.
A Trusted Key Management Scheme for Digital Rights Management
Jeong, Yeon-Jeong ; Yoon, Ki-Song ; Ryou, Jae-Cheol ;
ETRI Journal, volume 27, issue 1, 2005, Pages 114~114
In this paper, we propose a key management scheme which can provide delivery of the key used to encrypt a digital content from the package server to digital rights management (DRM) clients in a secure manner. The proposed scheme can protect digital content from attacks since an encrypted digital content is sent by a package server and only DRM clients can decrypt the encrypted digital content. It protects the key not only from purchasers but also among the other principals who manage the distribution and license servers.
Low-Temperature Growth of
Films by Plasma-Enhanced Atomic Layer Deposition
Lim, Jung-Wook ; Yun, Sun-Jin ; Lee, Jin-Ho ;
ETRI Journal, volume 27, issue 1, 2005, Pages 118~118
Silicon dioxide (
) films prepared by plasma-enhanced atomic-layer deposition were successfully grown at temperatures of
, showing self-limiting characteristics. The growth rate decreases with an increasing deposition temperature. The relative dielectric constants of
films are ranged from 4.5 to 7.7 with the decrease of growth temperature. A
film grown at
exhibits a much lower leakage current than that grown at
due to its high film density and the fact that it contains deeper electron traps.
Polymer Planar-Lightwave-Circuit-Type Variable Optical Attenuator Fabricated by Hot Embossing Process
Kim, Jin-Tae ; Choi, Choon-Gi ; Sung, Hee-Kyung ;
ETRI Journal, volume 27, issue 1, 2005, Pages 122~122
A polymer-based planar-lightwave-circuit-type variable optical attenuator (VOA) was fabricated using a hot embossing process. With an optimized one-step embossing process, forty micro-channels for the guidance of light were defined on a polymer thin film with an accuracy of
. The fabricated polymeric thermo-optic VOA shows 30 dB attenuation with 110 mW electrical input power at
. The rise and fall times are less than 5 ms.