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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 18, Issue 12 - Dec 1993
Volume 18, Issue 11 - Nov 1993
Volume 18, Issue 10 - Oct 1993
Volume 18, Issue 9 - Sep 1993
Volume 18, Issue 8 - Aug 1993
Volume 18, Issue 7 - Jul 1993
Volume 18, Issue 6 - Jun 1993
Volume 18, Issue 5 - May 1993
Volume 18, Issue 4 - Apr 1993
Volume 18, Issue 3 - Mar 1993
Volume 18, Issue 2 - Feb 1993
Volume 18, Issue 1 - Jan 1993
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A DCT Algorithm using shift and Additions
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 773~778
A new approach is proposed for the DCT which is widely utilized in the image processing, The approach replaces mutiplications with shift and additions, In the image restored by the proposed DCT and IDCT, no visible degration is observed and PSNR(Peak to Peak Signal to Noise Ratio) is greater than 35 dB for all cases, proving the usefulness of the proposal.
A Study on the Performance of Priority Mechanisms in ATM Multiplexer
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 779~792
In a switching node or an ATM multiplexer of the ATM network, a good bandwidth utilization can be achieved by the priority control using the 1-bit(Cell Loss priority) in ATM cell header. In this paper, the mixed mechanism is proposed to make up for shortcomings of existing space priority control mechanisms and to decrease the loss probability of high priority cell and its performance is analyzed about the cell loss probability. To estimate the performance of proposed mixed mechanism, its cell loss probability is compared with those of non-priority mechanism, push-out mechanism and partial buffer sharing mechanism. The cell loss probability is analyzed using a M/D/1/N modeling and a 2-state MMPP/D/1/N modeling and also comparison between two modelings is made. To verify this result of numerical analysis, the computer simulation is performed for each mechanism using the simulation language, SIMSRIPT II.5.
Characteristics of an External-Cavity Semiconductor Laser with a Fabry-Perrot Etalon inside the External reflector
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 793~801
We show theoretically that the performance characteristics of an external cavity semiconductor laser, such as frequency locking and frequency noise reduction, can be greatly improved by just inserting a high finesse Fabry-Perrot(F-P) etalon inside the external reflector. For example, when the F-P etalon of finesse 30 and optical thickness 1.5cm is inserted inside the external cavity of length 3.0cm, the frequency locking accuracy and the linewidth reduction ration are increased up to 7.6 times and 86 times respectively compared with the conventional external-cavity laser under the same operation condition.
A Study on Classification into Hangeul and Hanja in Text Area of Printed Document
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 802~814
This paper propose an algorithm for preprocessing of character recognition, which classify characters into Hangeul and Hanja. In this study, we use the 9 structural chacteristics of Hanja which isn't affected by deformation of size and style of characters and rates based on character size to classify characters. Firstly, we process the blocking to segment each characters. Secondly, on this segmented characters, we apply algorithm proposed in this paper to classify Hangeul and Hanja. Finally, we classify characters into Hangeul and Hanja, respectively. An experiment with 2350 Hangeul and 4888 Hanja printed Gothic and Mincho style of KS-C 5601 are carried out. We experiment on typeface sample book, newspapers, academic society's papers, magazines, textbooks and documents written out word processor to obtain the classifying rates of 98.8%, 92%, 96%, 98% and 98%, respectively.
A Study on the Convergence Characteristics Improvement of the Modified-Multiplication Free Adaptive Filer
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 815~823
In this paper, the structure of modified multiplication-free adaptive filter(M-MADF) and convergence analysis are presented. To evaluate the performance of proposed M-MADF algorithm, fractionally spaced equalizer (FSE) is used. The input signals are quantized using DPCM and the reference signals is processed using a first-order linear prediction filter, and the outputs are processed by a conventional adaptive filter. The filter coefficients are updated using the Sign algorithm. Under the assumption that the primary and reference signals are zero mean, wide-sense stationary and Gaussian, theoretical results for the coefficient misalignment vector and its autocorrelation matrix of the filter are driven. The convergence properties of Sign. MADF and M-MADF algorithm for updating of the coefficients of a digital filter of the fractionally spaced equalizer (FSE) are investigated and compared with one another. The convergence properties are characterized by the steady state error and the convergence speed. It is shown that the convergence speed of M-MADF is almost same as Sign algorithm and is faster that MADF in the condition of same steady error. Especially it is very useful for high correlated signals.
A Handover Algorithm Using Fuzzy Set Theory
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 824~834
In cellular mobile communication systems, if the size of a cell is decreasing for economic utilization of frequency resources, frequent handovers may be requested because the time a mobile stays in a cell is decreasing. In general the measured parameters to decide handover including RSSI, BER, and the distance between mobile station and base station, are usually incorrect and handover decision using single parameter insufficient. Therefore, the better handover algorithm should take over the problems of this uncertain measurements, and make the decision more robust and flexible by the consideration of all those decision parameters at the same time. We propose a novel handover algorithm based the multicriteria decision making, in which those parameters are participated in the decision process using aggregation function in fuzzy set theory. As a simulation results, the overall decision making is more reliable and flexible than the conventional method using only one parameter, RSSI in terms of call force ratio, and handover request ratio.
A Study on the Mixer for Satellite Communication at Ku-Band
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 835~840
In this paper a FET mixer is designed realized by small-signal S-parameter using microwave CAD, LINMIC + at Ku-band. The mixer has conversion gain 9.88dB at 14GHz RF, 1GHz IF, and + 1dBm LO imput. The maximum conversion gain is obtained 11.71dB at 1.1GHz. The result shows that the FET mixer does not need pre-and/or IF amplifier. The mixer maintains the desired conversion gain with low LO power level. The conversion gain of the mixer is higher than the available gain of a amplifier, which is experimentally verified.
Evaluation Method of Splicing Loss for Single Mode Optical Fiber
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 841~847
The evaluation methods of the splicing loss in attenuation characteristics of optical fiber were measured and analyzed presently, the splicing loss of single mode optical fiber is measured by the cut-back technique and the backscattering technique. Comparing the splicing loss measured by above two technique, evaluation method of splicing loss measured by backscattering technique (OTDR) shall be calculated by the splicing loss is occurred due to difference of the backscattering coefficient in the spliced fibers. Thus. this analysis of the splicing loss is certainly applied in installation of the optical fiber cables for management of the data.
A Study on the Properties of EMI filter for the Ni/Zn ratio of Ni-Zn Ferrite
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 848~853
The properties of ferrite bead, a low-pass filter, are determined by the frequency dispersion of the complex permeability. In this study, frequency dispersion of complex permeability of the Ni-Zn ferrites with different Ni/Zn ratio were investigated. Relationship between the behavior of filter and dispersion of complex permeability of a ferrite was studied. As a result, it was concluded that the compositions for Ni/Zn ratio of
, having high initial permeability and good sensitivity, were favorable as a ferrite bead filter.
Design of a New CMOS Differential Amplifier Circuit
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 854~862
All of the CMOS analog and analog-digital systems have composed with several basic circuits, and among them, a important block, the amplifier part can affect the system's performance, Therefore, according to the uses in the system, the amplifier circuit have designed as various architectures (high-gain, low-noise, high-speed circuit, etc...). In this paper, we have proposed a new CMOS differential amplifier circuit. This circuit is differential to single ended input stage comprised of CMOS complementary gain circuits having internally biasing configurations. These architectures can be achieved the high gain and reduced the transistors for biasing. As a results of SPICE simulation with the standard
processing parameter, the gain of the proposed circuit have a doubly value of the typical circuit's while maintaining other characteristics(phase margin, offset, etc...). And the proposed circuit is applicated in a simple CMOS comparator which has the settling time in 7nsec(CL=1pF) and the igh output swing
Design of New CMOS Differential Amplifier Circuit
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 863~870
A new methodology of multimedia data composition generated SRT(Synchronization Relation Tree) dynamically after user composing multimedia date by using high level user interface, and processes message passing protocols to adjust multimedia data temporal composition. In this paperl we propose SRT generating algorithm which transfer user defined timeline diagram to SRT dynamically. SRT generating algorithm is to use divide and conquer methodology and recurvise programming. And prove that it generates and type of multimedia date compositon to SRT.
Optical 2-bit Adder Using the Rule of Symbolic Substitiution
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 871~880
Conventional binary addition rules require a carry formation and propagation to the most significant bit, and lead to serial addition. Thus, the carry progapation in a binary addition stands as a hindrance to the full utilization of parallelism optics offers, Optical adders using a modified signed-digit(MSD) number system have been proposed to eliminate the carry propagation chain states to represent the three possible digits of MSD number system must encode three different states to represent the three possible digits of MSD. In the paper, we propose the design of a parallel optical adder based on 2-bit addition rules using the method of symbolic substitution(SS).
A New Stabilizing FTF Algorithm and Adaptive Equalization for Multipath Fading Channel
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 881~888
A new stabilizing algorithm for the fast transversal filter (FTF) which is known to exhibit a very unstable behavior, due basically to the accumulation in two different ways, we define a emasure counting these at each step of the algorithm in order to reduce the roundoff error. It has been shown that required amount of computation for the proposed algorithm is linearly increased as the order of equalizer and that stability is improved in comparison with the other existing algorithm. It has been shown that the proposed algorithm exhibits a good performance using computer simulation of adaptive equalization for multipath fading channel in urban mobile radio environment.
Queueing Analysis of the Finite Capacity ATM Multiplexer with the ON-OFF Input
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 889~894
Asychronous Transfer Mode (ATM) provides the means to transport different types of bursty traffic such as voice, video, and bulk data. To handle more efficiently the traffic sources and to increase the bandwidth utilization as much as possible, flexible statistical multiplexing schemes must be adopted for the ATM networks. This paper presents an efficient computational procedure to calculate the queue state distribution in a finite buffer queueing system with a number of independent input sources, and the cell loss probability is exactly calculated with the use of this recursion computation method. The cell loss probability is related to a ATM multiplexer with a homogeneous ON-OFF source is also investigated through numerical examples.
Subband Image Coding using Multirate Tree-Structured Vector Quantization
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 6, 1993, Pages 895~906
In this paper, MTSVQ(Multirate Tree-Structured Vector Quantization) is introduced for subband image coding. Original images are decomposed into a number of subband components, and multiresolution codebook is designed by MTSVQ algorithm. Optimal bit allocation among the subband components becomes the problem selecting the particular pruned subtree of MTSVQ which has the desired rate and distortion.