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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 28, Issue 6 - Dec 2006
Volume 28, Issue 5 - Oct 2006
Volume 28, Issue 4 - Aug 2006
Volume 28, Issue 3 - Jun 2006
Volume 28, Issue 2 - Apr 2006
Volume 28, Issue 1 - Feb 2006
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Widely Tunable Grating Cavity Lasers
Kwon, Oh-Kee ; Sim, Eun-Deok ; Kim, Kang-Ho ; Kim, Jong-Hoi ; Yun, Ho-Gyeong ; Kwon, O-Kyun ; Oh, Kwang-Ryong ;
ETRI Journal, volume 28, issue 5, 2006, Pages 545~554
A widely tunable multi-channel grating cavity laser is proposed and experimentally demonstrated. The device is implemented in Littman configuration with an echelle grating based on Rowland circle construction and realized by monolithically integrating all elements in an InP substrate. Lasing wavelength is selected by turning on an amplifier and the appropriate channel element in the array, and it is tuned by controlling light deflection electrically. The 6-channel device exhibits a tuning range of about 50 nm with a side mode suppression ratio of more than 30 dB. This is accomplished by adjusting the applied current of the dispersive element and phase control section.
Temperature, Current, and Voltage Dependences of Junction Failure in PIN Photodiodes
Park, Sahng-Gi ; Sim, Eun-Deok ; Park, Jeong-Woo ; Sim, Jae-Sik ; Song, Hyun-Woo ; Oh, Su-Hwan ; Baek, Yong-Soon ;
ETRI Journal, volume 28, issue 5, 2006, Pages 555~560
A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of
, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.
Broadcasting and Communication Convergent Network Based on MPEG-21: Design and Implementation of Multimedia Service Framework
Cho, Yong-Ju ; Kim, Jae-Gon ; Hong, Jin-Woo ;
ETRI Journal, volume 28, issue 5, 2006, Pages 561~573
In this paper, we present a practical implementation of the MPEG-21 multimedia framework for broadcasting and communication convergent services. MPEG-21 standard technology was exploited to build a convergent service framework. Using this framework, a service model and several scenarios have been successfully designed and implemented. In addition, interoperability, which is the main objective of a multimedia framework, especially in a convergent environment consisting of heterogeneous networks and various types of devices, has been addressed in detail. The experimental results show that the implemented test bed provides a next-generation multimedia service; that is, universal multimedia access (UMA), meeting the requirements of a broadcasting and communication convergent environment.
Fuzzy Logic Based Temporal Error Concealment for H.264 Video
Lee, Pei-Jun ; Lin, Ming-Long ;
ETRI Journal, volume 28, issue 5, 2006, Pages 574~582
In this paper, a new error concealment algorithm is proposed for the H.264 standard. The algorithm consists of two processes. The first process uses a fuzzy logic method to select the size type of lost blocks. The motion vector of a lost block is calculated from the current frame, if the motion vectors of the neighboring blocks surrounding the lost block are discontinuous. Otherwise, the size type of the lost block can be determined from the preceding frame. The second process is an error concealment algorithm via a proposed adapted multiple-reference-frames selection for finding the lost motion vector. The adapted multiple-reference-frames selection is based on the motion estimation analysis of H.264 coding so that the number of searched frames can be reduced. Therefore the most accurate mode of the lost block can be determined with much less computation time in the selection of the lost motion vector. Experimental results show that the proposed algorithm achieves from 0.5 to 4.52 dB improvement when compared to the method in VM 9.0.
Demonstration of Bidirectional Services Using MPEG-4 BIFS in Terrestrial DMB Systems
Shin, Ji-Tae ; Suh, Doug-Young ; Jeong, Yong-Chan ; Park, Seung-Ho ; Bae, Byung-Jun ; Ahn, Chung-Hyun ;
ETRI Journal, volume 28, issue 5, 2006, Pages 583~592
Digital broadcasting technology has developed focusing on multi-channel/multi-media, high-definition quality, and mobility-support. Recently, there has been a clear trend toward bidirectional service with the convergence between broadcasting and communication. The broadcasting viewer is no longer simply a passive receptor but has also become an information generator. Currently, the digital multimedia broadcasting (DMB) specifications are the major standard for portable digital broadcasting and have been establishing the overall guidelines for bidirectional service using the MPEG-4 system. While detailed specifications for DMB systems are not well-established for bidirectional service yet, they share the basic concepts underlying the European Eureka-147 Digital Audio Broadcasting (DAB) system. This paper develops key scenarios for bidirectional service in DMB, describes the signal transaction of broadcasting and return channels, and demonstrates typical scenarios using binary format for scenes (BIFS) in the MPEG-4 system.
Effective Admission Policy for Multimedia Traffic Connections over Satellite DVB-RCS Network
Pace, Pasquale ; Aloi, Gianluca ;
ETRI Journal, volume 28, issue 5, 2006, Pages 593~606
Thanks to the great possibilities of providing different types of telecommunication traffic to a large geographical area, satellite networks are expected to be an essential component of the next-generation internet. As a result, issues concerning the designing and testing of efficient connection-admission-control (CAC) strategies in order to increase the quality of service (QoS) for multimedia traffic sources, are attractive and at the cutting edge of research. This paper investigates the potential strengths of a generic digital-video-broadcasting return-channel-via-satellite (DVB-RCS) system architecture, proposing a new CAC algorithm with the aim of efficiently managing real-time multimedia video sources, both with constant and high variable data rate transmission; moreover, the proposed admission strategy is compared with a well-known iterative CAC mainly designed for the managing of real-time bursty traffic sources in order to demonstrate that the new algorithm is also well suited for those traffic sources. Performance analysis shows that, both algorithms guarantee the agreed QoS to real-time bursty connections that are more sensitive to delay jitter; however, our proposed algorithm can also manage interactive real-time multimedia traffic sources in high load and mixed traffic conditions.
Microstrip Slow-Wave Open-Loop Resonator Filters with Reduced Size and Improved Stopband Characteristics
Akkaraekthalin, Prayoot ; Jantree, Jaruek ;
ETRI Journal, volume 28, issue 5, 2006, Pages 607~614
This paper presents a new class of microstrip slow-wave open-loop resonator filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends loaded with triangular and rectangular ends is described, leading to the invention of a microstrip slow-wave open-loop resonator. Two-resonator and four-resonator bandpass filters are designed at the operating frequency of about 2 GHz, and a bandwidth of 60 MHz. The size of the slow-wave open-loop resonator is optimized from the standpoint of the unloaded Q-factor. The filters are not only compact in size due to the slow-wave effect, but also have a wider upper stopband resulting from the dispersion effect. The filter designs of this type are described in details. The experimental results are demonstrated and discussed.
Using MZIs for Optical PSBT Transmissions: Requirements for Thermal Stabilization
Ducournau, Guillaume ; Latry, Olivier ; Ketata, Mohamed ;
ETRI Journal, volume 28, issue 5, 2006, Pages 615~620
In this paper, we discuss the quantification of Mach-Zehnder interferometer (MZI) thermal stabilization which is needed in optical phase shaped binary transmission (PSBT) links. Considering the thermo-optic and thermal expansion effects, we revisit the analytical expression for the thermal drift (GHz/
) of the MZI center frequency (denoted here by the 'MZI spectral drift'). An MZI is then used in an experimental transmission system using the optical PSBT format. We study the effect of spectral MZI drift by using a thermally stabilized interferometer and applying a frequency shift to the optical carrier. By using the thermal drift coefficient of the MZI, we find that to ensure low bit error rate fluctuations due to the MZI drift, the thermal stabilization of the device must have an accuracy of
A Quantitative Analysis of the Effects of a Handset Subsidy on Consumer Welfare
Han, Sung-Soo ; Choi, Sung-Ho ; Kim, Byeong-Kwan ; Chung, Hyun ;
ETRI Journal, volume 28, issue 5, 2006, Pages 621~630
Observation of the effects of a handset subsidy on the mobile telecommunication industry has revealed two different aspects. The activation of various mobile services and the handset market, has led to the rapid acceleration of the related technological development, which is a desirable result, while rising prices and the overspending of related resources are undesirable. A great deal of research has been conducted to assess both desirable and undesirable factors using qualitative methods. However, quantitative studies into the effects of a handset subsidy are rare. In this study, we consider the positive and negative effects on consumer welfare of a change in demand and prices brought about by a handset subsidy. Then, we quantitatively compare the positive and negative effects and analyze their direct effects on consumer welfare.
Wavelength and Waveband Assignment for Ring Networks Based on Parallel Multi-granularity Hierarchical OADMs
Qi, Yongmin ; Su, Yikai ; Jin, Yaohui ; Hu, Weisheng ; Zhu, Yi ; Zhang, Yi ;
ETRI Journal, volume 28, issue 5, 2006, Pages 631~637
In this paper we study the optimization issues of ring networks employing novel parallel multi-granularity hierarchical optical add-drop multiplexers (OADMs). In particular, we attempt to minimize the number of control elements for the off-line case. We present an integer linear programming formulation to obtain the lower bound in optimization, and propose an efficient heuristic algorithm called global bandwidth resource assignment that is suitable for the design of large-scale OADM networks.
Stock Market Response to Acquisitions and Alliances in the European Telecom Industry: An Information Asymmetry Perspective
Sanchez-Lorda, Pablo ;
ETRI Journal, volume 28, issue 5, 2006, Pages 638~647
This paper investigates two kinds of strategic combinations carried out by the European telecom operators between 1986 and 2001: acquisitions, on the one hand, and strategic alliances, on the other. The aim of the paper is twofold. First, it analyzes the behavior adopted by these companies to adapt to an environment that, after the processes of globalization and privatization presents a clearly different structure. Second, it focuses on the effect that internationalization and diversification could exert over the returns obtained by the European telecom firms involved in acquisitions and alliances, differentiating when such strategic combinations are more profitable for the shareholders of the firms that carry them out.
Right-Angle-Bent CPW for the Application of the Driver-Amplifier-Integrated 40 Gbps TW-EML Module
Yun, Ho-Gyeong ; Choi, Kwang-Seong ; Kwon, Yong-Hwan ; Choe, Joong-Seon ; Moon, Jong-Tae ; Lee, Myung-Hyun ;
ETRI Journal, volume 28, issue 5, 2006, Pages 648~651
In this letter we present a right-angle-bent coplanar waveguide (CPW) which we developed for the application of the driver amplifier-integrated (DAI) 40 Gbps traveling wave electroabsorption modulated laser module. The developed CPW realized parallel progression of the radio frequency (RF) and light using a dielectric overlay structure and wedge bonding on the bending section. The measured
of the developed CPW were kept below-10 dB up to 35 GHz and -3 dB up to 43 GHz, respectively. These measured results of the CPW were in good agreement with the simulation results and demonstrated the applicability of the CPW to the 40 Gbps communication module.
Design of Middleware for Interactive Data Services in the Terrestrial DMB
Lee, Gwang-Soon ; Yang, Kyu-Tae ; Kim, Kwang-Yong ; Hahm, Young-Kwon ; Ahn, Chung-Hyun ; Lee, Soo-In ;
ETRI Journal, volume 28, issue 5, 2006, Pages 652~655
In this letter, we introduce a new middleware architecture and its generic application programming interface (API) (called the T-DMB MATE API) for terrestrial digital multimedia broadcasting (T-DMB). Middleware in T-DMB enables inter-operable applications to be downloaded from both broadcast and telecommunication networks in advance and to be executed in any type of T-DMB receiver. The middleware we introduce here is especially designed to support a proposed method for application provisions applied to a concept of application module appropriate to the service environment of T-DMB. We also verify the designed T-DMB MATE API through the implementation of the middleware and its application in a PC-based receiver.
A New Comb Circular Polarizer Suitable for Millimeter-Band Application
Eom, Soon-Young ; Korchemkin, Y.B. ;
ETRI Journal, volume 28, issue 5, 2006, Pages 656~659
This letter presents a new polarizer which has a simple comb structure inside a circular waveguide. The electrical performance of the proposed comb polarizer is optimized by a circular waveguide radius and by the physical parameters of the comb plates. This polarizer is suitable for providing good performance in millimeter-band application because of its simple structure and low fabrication cost. In our experiments the dual-band comb polarizer designed in band 1(K) and band 2(Ka) showed good electrical performance without any tuning elements.
Frame-Size Adaptive MAC Protocol in High-Rate Wireless Personal Area Networks
Choi, Eun-Chang ; Huh, Jae-Doo ; Kim, Kwang-Sik ; Cho, Moo-Ho ;
ETRI Journal, volume 28, issue 5, 2006, Pages 660~663
In this letter, we propose a frame-size adaptive MAC protocol for high rate wireless personal area networks (WPANs). In the proposed scheme, during communication, frame error rate is periodically reported to a transmitting device and the frame size is changed according to the measured results. Thus, the channel can be more effectively utilized by adapting to variable radio conditions. Analytical results show that this scheme achieves a much higher throughput than a non-frame-size adaptive media access control protocol in high-rate WPANs.
Audio Transcoding for Audio Streams from a T-DTV Broadcasting Station to a T-DMB Receiver
Bang, Kyoung-Ho ; Park, Young-Cheol ; Seo, Jeong-Il ;
ETRI Journal, volume 28, issue 5, 2006, Pages 664~667
We propose an efficient audio transcoding algorithm that can convert audio streams from terrestrial digital television broadcasting service stations to those for terrestrial digital multimedia broadcasting hand-held receivers. The proposed algorithm avoids the complicated psychoacoustic analysis by calculating the scalefactors of the bit-sliced arithmetic coding encoder directly from the signal-to-noise ratio parameters of the AC-3 decoder. The bit-allocation process is also simplified by cascading the nested distortion control loop. Through subjective evaluation, it is shown that the proposed algorithm provides comparable audio quality to tandem coding but it requires much smaller complexity.
Adaptive Scanning for H.264/AVC Intra Coding
Lee, Yung-Lyul ; Han, Ki-Hun ; Sim, Dong-Gyu ; Seo, Jeong-Il ;
ETRI Journal, volume 28, issue 5, 2006, Pages 668~671
In this letter, an adaptive scanning that improves intra coding efficiency in the H.264/AVC standard is proposed. The proposed adaptive scanning utilizes the prediction directions (modes) that include the horizontal and vertical edge information in a block. Depending on the prediction directions, the proposed method uses three scanning methods: zigzag scanning, horizontal scanning, and vertical scanning. In the proposed method, horizontal and vertical scanning are used in vertical and horizontal prediction modes, respectively, and the normal zigzag scanning in the H.264 standard is used in all other intra prediction modes. The proposed method reduces the bit rate by approximately 2.5% compared with H.264/AVC, without the degradation of video quality.
The Effect of Block Interleaving in an LDPC-Turbo Concatenated Code
Lee, Sang-Hoon ; Joo, Eon-Kyeong ;
ETRI Journal, volume 28, issue 5, 2006, Pages 672~675
The effect of block interleaving in a low density parity check (LDPC)-turbo concatenated code is investigated in this letter. Soft decoding can be used in an LDPC code unlike the conventional Reed-Solomon (RS) code. Thus, an LDPC-turbo concatenated code can show better performance than the conventional RS-turbo concatenated code. Furthermore, the performance of an LDPC-turbo code can be improved by using a block interleaver between the LDPC and turbo code. The average number of iterations in LDPC decoding can also be reduced by a block interleaver.
An Adaptive Hard Handoff Algorithm for Mobile Cellular Communication Systems
Zhu, Huamin ; Kwak, Kyung-Sup ;
ETRI Journal, volume 28, issue 5, 2006, Pages 676~679
In this letter, we propose an adaptive hard handoff algorithm with a dynamic hysteresis value based on the received signal strength from the serving base station, for mobile cellular communication systems. A discrete-time method is presented to evaluate handoff algorithms analytically. Performance is evaluated in terms of the average number of handoffs, the probability of link degradation, and the average handoff delay. Numerical results and simulations demonstrate that the proposed algorithm outperforms the handoff algorithm with fixed hysteresis values and the handoff algorithm using both threshold and hysteresis.
The Phase Estimation Algorithm of Arrival Phase Differences in Space-Time Coded Communication
Jung, Ji-Won ; Huang, Xinping ; Caron, Mario ; Kim, Min-Hyuk ; Kim, Ki-Man ; Yun, Young ;
ETRI Journal, volume 28, issue 5, 2006, Pages 680~683
One objective in developing the next generation of wireless communication systems is to increase data rates and reliability. A promising way to achieve this is to combine multiple-input and multiple-output signal processing with a space-time coding scheme, which offers higher coding and diversity gains and improves the spectrum efficiency and reliability of a wireless communication system. It is noted, however, that time delay differences and phase differences among different channels increase symbol interference and degrade system performance. In this letter, we investigate phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for the Rayleigh fading model to minimize their effects.
Performance Investigation of Space-Time Block Coded Multicarrier DS-CDMA in Time-Varying Channels
Narzullaev, Anvar ; Ryu, Kwan-Woong ; Park, Yong-Wan ;
ETRI Journal, volume 28, issue 5, 2006, Pages 684~687
In this letter, we evaluate the system performance of a space-time block coded (STBC) multicarrier (MC) DS-CDMA system over a time selective fading channel, with imperfect channel knowledge. The average bit error rate impairment due to imperfect channel information is investigated by taking into account the effect of the STBC position. We consider two schemes: STBC after spreading and STBC before spreading in the MC DS-CDMA system. In the scheme with STBC after spreading, STBC is performed at the chip level; in the scheme with STBC before spreading, STBC is performed at the symbol level. We found that these two schemes have various channel estimation errors, and that the system with STBC before spreading is more sensitive to channel estimation than the system with STBC after spreading. Furthermore, derived results prove that a high spreading factor (SF) in the MC DS-CDMA system with STBC before spreading leads to high channel estimation error, whereas for a system with STBC after spreading this statement is not true.
Superimposed Pilot Aided Multiuser Channel Estimation for MIMO-OFDM Uplinks
Yang, Qinghai ; Kwak, Kyung-Sup ;
ETRI Journal, volume 28, issue 5, 2006, Pages 688~691
This letter addresses the superimposed pilot aided multiuser channel estimation for the uplinks of multi-input multi-output orthogonal frequency-division multiplexing systems. To mitigate the embedded-data effects on the performance of channel estimation, a novel combining algorithm is proposed. Optimal pilot symbols are developed with respect to the least square channel estimate's mean square error. The averaged sum-capacity lower bound is derived and simulated. Simulation results show that on a low signal-to-noise ratio regime, our proposed scheme achieves better performance and higher capacity than the conventional pilot aided approach.
Cost Optimization in SIS Model of Worm Infection
Kim, Jong-Hyun ; Radhakrishnan, Sridhar ; Jang, Jong-Soo ;
ETRI Journal, volume 28, issue 5, 2006, Pages 692~695
Recently, there has been a constant barrage of worms over the Internet. Besides threatening network security, these worms create an enormous economic burden in terms of loss of productivity not only for the victim hosts, but also for other hosts, as these worms create unnecessary network traffic. Further, measures taken to filter these worms at the router level incur additional network delays because of the extra burden placed on the routers. To develop appropriate tools for thwarting the quick spread of worms, researchers are trying to understand the behavior of worm propagation with the aid of epidemiological models. In this study, we present an optimization model that takes into account infection and treatment costs. Using this model we can determine the level of treatment to be applied for a given rate of infection spread.