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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 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
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A Novel Process for Fabricating High Density Trench MOSFETs for DC-DC Converters
Kim, Jong-Dae ; Roh, Tae-Moon ; Kim, Sang-Gi ; Park, Il-Yong ; Yang, Yil-Sulk ; Lee, Dae-Woo ; Koo, Jin-Gun ; Cho, Kyoung-Ik ; Kang, Young-Il ;
ETRI Journal, volume 24, issue 5, 2002, Pages 333~333
We propose a new process technique for fabricating very high-density trench MOSFETs using 3 mask layers with oxide spacers and a self-aligned technique. This technique reduces the device size in trench width, source, and p-body region with a resulting increase in cell density and current driving capability as well as cost-effective production capability. We were able to obtain a higher breakdown voltage with uniform oxide grown along the trench surface. The channel density of the trench DMOSFET with a cell pitch of 2.3-2.4
was 100 Mcell/
and a specific on-resistance of 0.41
was obtained under a blocking voltage of 43 V.
An Asymmetric Sampled Grating Laser and Its Application to Multi-Wavelength Laser Array
Ryu, Sang-Wan ; Kim, Je-Ha ;
ETRI Journal, volume 24, issue 5, 2002, Pages 341~341
We propose an asymmetric sampled grating laser and a multi-wavelength laser array associated with it. Asymmetric sampling periods combined with an index shifter make it possible to use first order reflection for lasing operations. With the structure of our design, we achieved a simple fabrication procedure as well as a high yield without using complex and time-consuming e-beam lithography for multi-period gratings. We analyzed the effect of mirror coating by numerical analysis to improve single mode and power extraction performance. By using high reflection-antireflection coatings, we obtained high power extraction efficiency without degradation of the single mode property. For the multi-wavelength laser array, to gain wavelength control, we varied the sampling periods from one laser to an adjacent laser across the array. With this approach, we showed the feasibility of an array of up to 30 channels with 100 GHz wavelength spacing.
Microstructure and Electrical Properties of Low Temperature Processed Ohmic Contacts to p-Type GaN
Park, Mi-Ran ; Song, Young-Joo ; Anderson, Wayne A. ;
ETRI Journal, volume 24, issue 5, 2002, Pages 349~349
With Ni/Au and Pd/Au metal schemes and low temperature processing, we formed low resistance stable Ohmic contacts to p-type GaN. Our investigation was preceded by conventional cleaning, followed by treatment in boiling
:HCl (1:3). Metallization was by thermally evaporating 30 nm Ni/15 nm Au or 25 nm Pd/15 nm Au. After heat treatment in
at various temperatures, the contacts were subsequently cooled in liquid nitrogen. Cryogenic cooling following heat treatment at
decreased the specific contact resistance from
for the Ni/Au contacts, while this increased it from
for the Pd/Au contacts. The Ni/Au contacts showed slightly higher specific contact resistance than the Pd/Au contacts, although they were more stable than the Pd contacts. X-ray photoelectron spectroscopy depth profiling showed the Ni contacts to be NiO followed by Au at the interface for the Ni/Au contacts, whereas the Pd/Au contacts exhibited a Pd:Au solid solution. The contacts quenched in liquid nitrogen following sintering were much more uniform under atomic force microscopy examination and gave a 3 times lower contact resistance with the Ni/Au design. Current-voltage-temperature analysis revealed that conduction was predominantly by thermionic field emission.
A Modified Dynamic Weighted Round Robin Cell Scheduling Algorithm
Kwak, Ji-Young ; Nam, Ji-Seung ; Kim, Do-Hyun ;
ETRI Journal, volume 24, issue 5, 2002, Pages 360~360
In this paper, we propose the modified dynamic weighted round robin (MDWRR) cell scheduling algorithm, which guarantees the delay property of real-time traffic and also efficiently transmits non-real-time traffic. The proposed scheduling algorithm is a variation of the dynamic weighted round robin (DWRR) algorithm and guarantees the delay property of real-time traffic by adding a cell transmission procedure based on delay priority. It also uses a threshold to prevent the cell loss of non-real-time traffic that is due to the cell transmission procedure based on delay priority. Though the MDWRR scheduling algorithm may be more complex than the conventional DWRR scheme, considering delay priority minimizes cell delay and decreases the required size of the temporary buffer. The results of our performance study show that the proposed scheduling algorithm has better performance than the conventional DWRR scheme because of the delay guarantee of real-time traffic.
Visual Cryptography Based on an Interferometric Encryption Technique
Lee, Sang-Su ; Na, Jung-Chan ; Sohn, Sung-Won ; Park, Chee-Hang ; Seo, Dong-Hoan ; Kim, Soo-Joong ;
ETRI Journal, volume 24, issue 5, 2002, Pages 373~373
This paper presents a new method for a visual cryptography scheme that uses phase masks and an interferometer. To encrypt a binary image, we divided it into an arbitrary number of slides and encrypted them using an XOR process with a random key or keys. The phase mask for each encrypted image was fabricated nuder the proposed phase-assignment rule. For decryption, phase masks were placed on any path of the Mach-Zehnder interferometer. Through optical experiments, we confirmed that a secret binary image that was sliced could be recovered by the proposed method.
A Performance Analysis of TMN Systems Using Models of Networks of Queues, Jackson's Theorem, and Simulation
Hwang, Young-Ha ; Chung, Sang-Wook ; Lee, Gil-Haeng ; Kim, Young-Il ;
ETRI Journal, volume 24, issue 5, 2002, Pages 381~381
We analyze the performance of a telecommunications management network (TMN) system using models of networks of queues, Jackson's theorem, and simulation. TMN systems for managing public asynchronous transfer mode (ATM) networks generally have a four-level hierarchical structure consisting of a network management system, a few element management systems (EMSs), and several pairs of agents and ATM switches. We construct a Jackson's queuing network and present formulae to calculate its performance measures: distributions of queue lengths and waiting times, mean message response time, and maximum throughput. We perform a numerical analysis and a simulation analysis and compare the results.
A DSP Architecture for High-Speed FFT in OFDM Systems
Lee, Jae-Sung ; Lee, Jeong-Hoo ; SunWoo, Myung-H. ; Moh, Sang-Man ; Oh, Seong-Keun ;
ETRI Journal, volume 24, issue 5, 2002, Pages 391~391
This paper presents digital signal processor (DSP) instructions and their data processing unit (DPU) architecture for high-speed fast Fourier transforms (FFTs) in orthogonal frequency division multiplexing (OFDM) systems. The proposed instructions jointly perform new operation flows that are more efficient than the operation flow of the multiply and accumulate (MAC) instruction on which existing DSP chips heavily depend. We further propose a DPU architecture that fully supports the instructions and show that the architecture is two times faster than existing DSP chips for FFTs. We simulated the proposed model with a Verilog HDL, performed a logic synthesis using the 0.35
standard cell library, and then verified the functions thoroughly.
An Etch-Stop Technique Using
Thin Film and Its Application to Silica PLC Platform Fabrication
Shin, Jang-Uk ; Kim, Dong-June ; Park, Sang-Ho ; Han, Young-Tak ; Sung, Hee-Kyung ; Kim, Je-Ha ; Park, Soo-Jin ;
ETRI Journal, volume 24, issue 5, 2002, Pages 398~398
thin film, we developed a novel etch-stop technique for the protection of silicon surface morphology during deep ion coupled plasma etching of silica layers. With this technique we were able to etch a silica trench with a depth of over 20
without any damage to the exposed silicon terrace surface. This technique should be well applicable to fabricating silica planar lightwave circuit platforms for opto-electronic hybrid integration.
A New Robust Watermark Embedding into Wavelet DC Components
Joo, Sang-Hyun ; Suh, Young-Ho ; Shin, Jae-Ho ; Kikuchi, Hisakazu ;
ETRI Journal, volume 24, issue 5, 2002, Pages 401~401
In this paper, we propose a non-blind watermarking method that embeds a pseudo-random sequence (watermarks) into wavelet DC components. The DC area is not suitable for embedding because of severe visual degradation. We overcome the degradation problem by embedding watermarks into visually insensitive locations. We compare our experimental results with respect to JPEG compression with Cox’s popular correlation-based method. We also compare the robustness of our technique with other methods registered in CheckMark. This study reveals that the proposed method simultaneously provides good fidelity in quality as well as robustness against external attacks.
Resynchronization of Modified JPEG Using a Power Allocation Scheme in a Direct Sequence CDMA System
Yim, Choon-Sik ; Roh, Jae-Sung ; Choi, Eun-Suk ; Baek, Joong-Hwan ; Cho, Sung-Joon ;
ETRI Journal, volume 24, issue 5, 2002, Pages 405~405
In this paper, we discuss recovery schemes for errors occurring when image data encoded with variable length coding (VLC) is transmitted through additive white Gaussian noise (AWGN) and multiple-access interference in direct sequence code division multiple access (DS/CDMA) systems. VLC such as JPEG is so sensitive to channel errors that severe degradation in decoded images occurs even if only one or two bits have errors. This is due to the loss of synchronization at the image decoder. We propose a resynchronization scheme using a power allocation method in wireless DS/CDMA transmission. Through simulation, we know that the proposed method has a more robust resynchronization capability and higher objective and subjective quality than the conventional method.