Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal Basic Information
Journal DOI :
Electronics and Telecommunications Research Institute
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2002
Volume 24, Issue 5 - Oct 2002
Volume 24, Issue 4 - Aug 2002
Volume 24, Issue 3 - Jun 2002
Volume 24, Issue 2 - Apr 2002
Volume 24, Issue 1 - Feb 2002
Selecting the target year
A Novel Audio Watermarking Algorithm for Copyright Protection of Digital Audio
Seok, Jong-Won ; Hong, Jin-Woo ; Kim, Jin-Woong ;
ETRI Journal, volume 24, issue 3, 2002, Pages 181~181
Digital watermark technology is now drawing attention as a new method of protecting digital content from unauthorized copying. This paper presents a novel audio watermarking algorithm to protect against unauthorized copying of digital audio. The proposed watermarking scheme includes a psychoacoustic model of MPEG audio coding to ensure that the watermarking does not affect the quality of the original sound. After embedding the watermark, our scheme extracts copyright information without access to the original signal by using a whitening procedure for linear prediction filtering before correlation. Experimental results show that our watermarking scheme is robust against common signal processing attacks and it introduces no audible distortion after watermark insertion.
Millimeter Wave MMIC Low Noise Amplifiers Using a 0.15
Commercial pHEMT Process
Jang, Byung-Jun ; Yom, In-Bok ; Lee, Seong-Pal ;
ETRI Journal, volume 24, issue 3, 2002, Pages 190~190
This paper presents millimeter wave monolithic microwave integrated circuit (MMIC) low noise amplifiers using a
commercial pHEMT process. After carefully investigating design considerations for millimeter-wave applications, with emphasis on the active device model and electomagnetic (EM) simulation, we designed two single-ended low noise amplifiers, one for Q-band and one for V-band. The Q-band two stage amplifier showed an average noise figure of 2.2 dB with an 18.3 dB average gain at 44 GHz. The V-band two stage amplifier showed an average noise figure of 2.9 dB with a 14.7 dB average gain at 65 GHz. Our design technique and model demonstrates good agreement between measured and predicted results. Compared with the published data, this work also presents state-of-the-art performance in terms of the gain and noise figure.
Radiation Pattern of Multibeam Array Antenna with Digital Beamforming for Stratospheric Communication System: Statistical Simulation
Ku, Bon-Jun ; Ahn, Do-Seob ; Lee, Seong-Pal ; Shishlov, A.V. ; Reutov, A.S. ; Ganin, S.A. ; Shubov, A.G. ;
ETRI Journal, volume 24, issue 3, 2002, Pages 197~197
This paper presents the results of the numerical simulation of a multibeam active phased array antenna for a High Altitude Platform Station (HAPS). The simulation takes into account the random errors caused by the non-identity of the array elements and the inaccuracy of the antenna calibration. The results of our statistical simulation show that the strict requirements on the sidelobe envelope for HAPSs can be met when the amplitude and phase distribution errors are minor, a condition which may be achieved by using digital beamforming.
Simple Near-Field Optical Recording Using Bent Cantilever Probes
Kim, Jeong-Yong ; Song, Ki-Bong ; Park, Kang-Ho ; Lee, Hyo-Won ; Kim, Eun-Kyoung ;
ETRI Journal, volume 24, issue 3, 2002, Pages 205~205
This paper describes our high-density near-field optical recording using bent cantilever fiber probes installed in an atomic force microscope. We conducted a near-field reading of nano-scale hole patterns with a 100 nm spatial resolution and a 25
/s scan speed; this implies a capability of a data reading density of 60 Gb/
with a 0.25 kbps data transfer rate. In addition, we investigated re-writable near-field recording on photochromic diarylethene films. We successfully recorded erasable memory bits having a minimum width of 600 nm in a writing time as short as 30ms. We found that using a cantilever probe simplifies the setup and operation of the near-field optical recording system and may offer multifunctional recording capabilities.
Characterization of Via Etching in
Magnetically Enhanced Reactive Ion Etching Using Neural Networks
Kwon, Sung-Ku ; Kwon, Kwang-Ho ; Kim, Byung-Whan ; Park, Jong-Moon ; Yoo, Seong-Wook ; Park, Kun-Sik ; Bae, Yoon-Kyu ; Kim, Bo-Woo ;
ETRI Journal, volume 24, issue 3, 2002, Pages 211~211
This study characterizes an oxide etching process in a magnetically enhanced reactive ion etching (MERIE) reactor with a
gas chemistry. We use a statistical
experimental design plus one center point to characterize the relationships between the process factors and etch responses. The factors that we varied in the design include RF power, pressure, and gas composition, and the modeled etch responses were the etch rate, etch selectivity to TiN, and uniformity. The developed models produced 3D response plots. Etching of
mainly depends on F density and ion bombardment.
etch selectivity to TiN sensitively depends on the F density in the plasma and the effects of ion bombardment. The process conditions for a high etch selectivity are a 0.3 to 0.5
flow ratio and a -600 V to -650 V DC bias voltage according to the process pressure in our experiment. Etching uniformity was improved with an increase in the
flow ratio in the gas mixture, an increase in the source power, and a higher pressure. Our characterization of via etching in a
MERIE using neural networks was successful, economical, and effective. The results provide highly valuable information about etching mechanisms and optimum etching conditions.
Two-Photon Absorption Cross Sections of Dithienothiophene-Based Molecules
Chung, Myung-Ae ; Lee, Kwang-Sup ; Jung, Sang-Don ;
ETRI Journal, volume 24, issue 3, 2002, Pages 221~221
We performed nonlinear transmission measurements and quantum-chemical calculations on dithienothiophene(DTT)-based molecules to gain insight into the effect of acceptor and donor groups on two-photon absorption(TPA) properties. The TPA intensity showed dispersion characteristics of the single-photon absorption spectrum. When the molecules included an asymmetric donor-acceptor pair, the single- and two-photon absorption maximum wavelengths were red-shifted more than when the molecules had a symmetric donor-donor structure. We interpreted this result as indicating that the
state plays the dominating role in the absorption process of molecules with a symmetric structure. The experimental TPA
values at the absorption peak wavelength showed a dependence on the structural variations. We found the self-consistent force-field theory and Hartree-Fock Hamiltonian with single configuration interaction formalism to be valid for evaluating TPA
. Although the quantum-chemical calculations slightly underestimated the experimental
values obtained from nonlinear trans -mission measurements, they reasonably predicted the dependence of the
value on the structural variations. We confirmed the role of molecular symmetry by observing that donor-donor substituted structure gave the highest experimental and theoretical TPA
values and that the donor-acceptor substituted structure showed a greater red-shift in the TPA absorption maximum wavelength. Overall, the theoretical
values of DTT-based molecules were in the order of
and are higher than that of AF-50 by nearly two orders of magnitude.
Integrating Spatial and Temporal Relationship Operators into SQL3 for Historical Data Management
Lee, Jong-Yun ;
ETRI Journal, volume 24, issue 3, 2002, Pages 226~226
A spatial object changes its states over time. However, existing spatial and temporal database systems cannot fully manage time-varying data with both spatial and non-spatial attributes. To overcome this limitation, we present a framework for spatio-temporal databases that can manage all time-varying historical information and integrate spatial and temporal relationship operators into the select statement in SQL3. For the purpose of our framework, we define three referencing macros and a history aggregate operator and classify the existing spatial and temporal relationship operators into three groups: exclusively spatial relationship operators, exclusively temporal relationship operators, and spatio-temporal common relationship operators. Finally, we believe the integration of spatial and temporal relationship operators into SQL3 will provide a useful framework for the history management of time-varying spatial objects in a uniform manner.
A Non-Canonical Linearly Constrained Constant Modulus Algorithm for a Blind Multiuser Detector
Jiang, Hong-Rui ; Kwak, Kyung-Sup ;
ETRI Journal, volume 24, issue 3, 2002, Pages 239~239
We investigate an alternative blind adaptive multiuser detection scheme based on a non-canonical linearly constrained constant modulus (LCCM) criterion and prove that, under the constrained condition, the non-canonical linearly constrained constant modulus algorithm (LCCMA) can completely remove multiple -access interference. We further demonstrate that the non-canonical LCCM criterion function is strictly convex in the noise-free state, and that under the constrained condition, it is also strictly convex even where small noise is present. We present a simple method for selecting the constant as well as a stochastic gradient algorithm for implementing our scheme. Numerical simulation results verify the scheme's efficiency.
Low-Complexity Symbol Timing Offset Estimation Schemes for OFDM Systems
Park, So-Ra ; Jung, Young-Ho ; Lee, Son-In ;
ETRI Journal, volume 24, issue 3, 2002, Pages 247~247
In this paper, we propose three symbol syn-chronization schemes for Orthogonal Frequency Division Multiplex (OFDM) systems. The cyclic extension preceding OFDM symbols is of decisive importance for these schemes. The first scheme uses the phase-differential coding of the received OFDM signal. The second and the third schemes use the length of the received OFDM signal. All three schemes make symbol synchronization possible, even though there is a frequency off-set in the system. Simulation results show that these schemes can be used to synchronize an OFDM system over AWGN and multi-path fading channels.
Optimal Design of Superframe Pattern for DVB-RCS Return Link
Lee, Ki-Dong ; Cho, Yong-Hoon ; Lee, Seung-Joon ; Lee, Ho-Jin ;
ETRI Journal, volume 24, issue 3, 2002, Pages 251~251
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.
Single Mode Laser Oscillation in an Nd-Doped Large Core Double Clad Fiber Cavity with Concatenated Adiabatic Tapers
Seo, Hong-Seok ; Choi, Yong-Gyu ; Kim, Kyung-Hon ; Jeong, Hoon ; Oh, Kyung-Hwan ;
ETRI Journal, volume 24, issue 3, 2002, Pages 255~255
We created a new design for an Nd-doped clad-pumped silica fiber laser to enhance the pump absorption and lasing efficiency for a butt-coupled, end-pumped scheme. Two concatenated adiabatic tapers formed within the laser cavity simultaneously removed higher order modes and were spliced to conventional single mode fibers. We theoretically analyzed mode propagation along the composite cavity and experimentally achieved continuous wave oscillation in the
and a laser output power of over 820 mW with a slope efficiency of 27%.