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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 17, Issue 12 - Dec 1992
Volume 17, Issue 11 - Nov 1992
Volume 17, Issue 10 - Oct 1992
Volume 17, Issue 9 - Sep 1992
Volume 17, Issue 8 - Aug 1992
Volume 17, Issue 7 - Jul 1992
Volume 17, Issue 6 - Jun 1992
Volume 17, Issue 5 - May 1992
Volume 17, Issue 4 - Apr 1992
Volume 17, Issue 3 - Mar 1992
Volume 17, Issue 2 - Feb 1992
Volume 17, Issue 1 - Jan 1992
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A Study on the Printed Korean and Chinese Character Recognition
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1175~1184
A new classification method and recognition algorithms for printed Korean and Chinese character is studied for Korean text which contains both Korean and Chinese characters. The proposed method utilizes structural features of the vertical and horizontal vowel in Korean character. Korean characters are classified into 6 groups. Vowel and consonant are separated by means of different vowel extraction methods applied to each group. Time consuming thinning process is excluded. A modified crossing distance feature is measured to recognize extracted consonant. For Chinese character, an average of stroke crossing number is calculated on every characters, which allows the characters to be classified into several groups. A recognition process is then followed in terms of the stroke crossing number and the black dot rate of character. Classification between Korean and Chinese character was at the rate of 90.5%, and classification rate of Ming-style 2512 Korean characters was 90.0%. The recognition algorithm was applied on 1278 characters. The recognition rate was 92.2%. The densest class after classification of 4585 Chinese characters was found to contain only 124 characters, only 1/40 of total numbers. The recognition rate was 89.2%.
A Study on the Characteristics of noise smoothing in FIR-Median Hybrid Filters
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1185~1198
In this paper, the differential weighted algorithm proposed in order to improve th noise smoothing characteristics of conventional Median filter and FIR-Median Hybrid filter. Performance of some image restoration filter(median filter, FIR-Median Hybird filter, FIR-Median Hybrid filter to proposed differential weighted algorithm) are compared and evaluated on the noise smoothing characteristics and sharp edge conservation characteristics. Test and Real images used in this paper are Lenna and Urological images corrupted by impulse, gaussian, exponential and laplacian noise. Experimental results show that the FIR-Median Hybrid filter applied to the differential weighted algorithm are comparatively superior to others. But the filter orders have increased, the more time consumed to image processing. Hence if the adequate filtering by the type of image is selected. now after a great support will be take consideration into the various parts of application by computer science and of medical image processing.
Isolated-Word Recognition Using Neural Network and Hidden Markov Model
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1199~1205
In this paper, a Korean word recognition method which usese Neural Network and Hidden Markov Models(HMM) is proposed to improve a recognition rate with a small amount of learning data. The method reduces the fluctuation due to personal differences which is a problem to a HMM recognition system. In this method, effective recognizer is designed by the complement of each recognition result of the Hidden Markov Models(HMM) and Neural Network. In order to evaluate this model, word recognition experiment is carried out for 28 cities which is DDD area names uttered by two male and a female in twenties. As a result of testing HMM with 8 state, codeword is 64, the recognition rate 91[%], as a result of testing Neural network(NN) with 64 codeword the recognition rate is 89[%]. Finally, as a result of testing NN-HMM with 64 codeword which the best condition in former tests, the recognition rate is 95[%].
A Study on Interconnectioned LAN of Token Ring Network
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1206~1218
Token ring systems which control to switch the data stream of networks by passing the token have been widely used to medium access controls in many ring or bus topology LANs. The system could be modeled for analysis as single-server-multi-queue system of the cyclic service method. These concepts could be expanded to multi-token ring systems interconnected with single ring consisting of bridges implemented simply to be stored and transmitted. In the proposal for the performance analysis of the interconnected token ring system, in has been assumed M/G/1 queueing model that frame arrivals are the Poisson process at each station queue and frame sizes are independently and identically distributed. And the average time delays were analyzed mathematically for arbitrary frame transferred from source station to destination area. The time delay of the frame transmission could be explained as the sum of the average time which the token passed from arbitrary position to source station, such as the waiting time in the source station transferring the previous arrival frames, and the propagation time from source station to interdestinated point. These delays were given as the sum of the duration from inner and outer bridge queues, the time delays from inner and outer bridge queues, and the time from outer bridge queue to destination station. These results were investigated by varing parameters effected to total time delays. In the results, those factors to be effected to dominant the total time delays were increased were in the cases of the high arrival rates and the high ration of destination of the other outerring. The system were shown the time delays increased exponentially in spite of the priority service policy. In order to decreasing the number of outerrings and increasing the number of nodes in backbone relatively, so the systems could be decreased the total delay in the interconnected token ring system.
A Study on the Implementation of Register Based VXIbus System
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1219~1227
VXIbus is a standard for compatibility of instruments of multi-vendors and originated from the VMEbus. The devices for implementing VXIbus system can be categorized into the register based device and the message based device. In this paper we organized the A/D conversion module and the slot0 module, which form the register based VXIbus subsystem. The A/D conversion module is used as a digital voltmeter and LAN is used for communication between an external control computer and the slot0 module. The SCPI(Standard Commands for Programmable Instruments), which is a standard language for instruments, is transmitted from the external control computer to the slot0 module as the ASCII form, and then to the A/D conversion module after changing to the binary digit command. From the experiment. We verified that the measured voltage can be observed on external control computer and user interface can be improved by the modified graphic processing.
Network Management Script Construction in Delegation Model
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1228~1237
Network management represents those activities which control and moitor the use of resources. Remote delegation model supports flexible and effective distribution of management functions among managers and agents, and it may cause an reliable network management in a relatively complex and high-speed networks. in this model, managers delegate to agents execution of management programs as prescribed in a management scripting language. In addition, primitives included in the management programs enable agents to monitor and control localmanaged objects effectively. We suggest management algorithms in which management scripts are delegated from managers to agents and partiality implement OSI fault management. This mans gement algorithm can effectively support delegation and control concurrent accesses to management information. Moreover, it can be easily translated into object-based concurrent programming language: ABCL. In this paper, we will scrutinize some essential aspects of this management.
Development of an International Time Comparison System via GMS
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1238~1246
We developed a time comparison system using the ranging signal of the geostationary meteorological satellite(GMS). By using the system time comparison between the KRISS(Korea Research Institute of Standards and Science) cesium atomic clock and the GMS ranging signal has been carried out and the results have shown that the precision of time comparison at KRISS is about 10 ns. For the more accurate measurements we calibrated the receiver delay time between KRISS receiver and CRL(Communications Research Laboratory) receiver by using the portable GMS receiver.
Design and Implementation of VHDL Environment
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1247~1263
VHDL, which is the IEEE standard HDL, has gradually become popular in the area of hardware design, the VHDL Environment developed in this study consists of VHDL Support Environment and VHDL Using Environment. The VHDL Support Environment is composed of Analyzer, CDFG Generator for synthesis, Synthesizer, and VHDL Generator converting CDFG to VHDL. The VHDL Using Environment provides users with more convenient access to the VHDL Support Environment. The VHDL Using Environment allows accessing the tools in the VHDL Support Environment through Graphical User Interface. VHDL program can be automaticaly generated from schematics in the VHDL Using Environment.
A Study on Hybrid Median Filter Using Gray Scale Morphology
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1264~1270
MF(Morphological filter) is generally composed of several morphological operation, which are the diverse structuring element. The two basic operation are erosion and dilation. The two other operation, opening and closing, are defined based on these two operation. Performance of open-closing(OC) is better exellent than close-opening(CO) to reduce noise of image data with Gaussian noise. In this paper, to use the hybrid median filter in processing the image, is shown that hybrid median filter has better results image quality than other filters, to analyze by computer simulation.
The Performance Evaluation of FH-SSMA Radio Systems
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1271~1278
In this paper, a practical model for evaluating and comparing the bit error rates(BERs) due to adjacent channel mutual interference in a synchronous and asynchronous frequency hopped spread spectrum multiple access(FH-SSMA) radio communication systems is proposed. After implementing the actual FH radio in both the sychronous and asynchronous case, the BER is computed and measured. An experiment of this system in mobile tactical environments reveals that the performance in the asynchronous case is lower than that of the synchronous case. The computer simulation model is an efficient tool for designing practical FH radios in mobile communication environments.
Comparative Study of the System Operational Method for Fault-Tolernace
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1279~1289
Fault-tolerant system in improved the reliability and safety by using hardware and software redundancy. Fault mask and detection, identification techniques are conditionally used with system's application areas. Here DMR system is operated with standby and fail-safe module method that has minimal hardware and software redundancy, then its reliablity and safety comparison is presented respectively. Also this paper proposed an effective methods of dealing with transient faults as compared system's MTTFs to transient faults tolerance capabilities of self-diagnosis program.
Analytical modeling for the short-channel MOSFET
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1290~1298
In this paper, the Poisson's equation is solved two-dimensionally without employing any fitting parameters, and the model formulation of a short-channel MOSFET is accomplished fully analytically. It automatically derives a very accurate drain current expression that can be used simultaneously for strong inversion, subthreshold, and saturation regions. Furthermore, this model gives a unified explanation for the short-channel effect, the body effect, the DIBL effect, and even the variation of the effective carrier mobility. The obtained expression of the threshold voltage also includes the dependence on the oxide thickness, the n+ junction depth, and temperature.
Performance Evaluation of Symbol Timing Algorithm for QPSK Modulation Technique in Digital Receiver
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1299~1310
Recently, digital realizations of timing recovery circuits for digital data transmission are of growing interest. As a result of digital realization of timing recovery circuits, new digital algorithms for timing error detection are required. In this paper, we present a new digital Angular Form(AF) algorithm which can be directly applied to QPSK modulation technique. AF algorithm is basically developed on the concepts of detected angle form and transition logic table. We evaluated the performance of this algorithm by Monte-Carlo simulation method under Gaussian and Impulsive noise environments. From the performance evaluation result, we show that the performance of AF Algorithm is better than that of Gardner in BER, RMS jitter, S-curve.
Error Rate Performance of FH/MFSK Signal with Diversity and Coding Technique in the Interference and Fading Environments
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1311~1319
In the partial-band interference and Rayleigh fading environments, the bit error probability equation of FH/MFSK signal has been derived and the error rate has been evaluated. And the results are shown in graphs and discussed. Here, to improve the error rate performance the repeated diversity and the error-correction coding techniques are adopted. The degree of improvement of error rate performance has been found out in diversity and coding techniques respectively. In diversity case, repetition number is taken as a parameter and in coding case, as the error-correction codes Hamming code, BCH code, and convolutional code are introduced. From the obtained results, we have known that the increase of the number of repetition in diversity technique has been brought a little improvement of performance but the coding technique considerable improvement and in particular, convolutional code is very effective. Therefore, coding technique is considered to be better than repeated diversity to cope with Rayleigh fading and partial-band interference.
Error Rate Performance of FH/MFSK Signal with Partial-Band Interference in m-distribution Fading Environment
The Journal of Korean Institute of Communications and Information Sciences, volume 17, issue 11, 1992, Pages 1320~1331
The error rate equation of FH/MFSK signal of repeated diversity received over m-distribution fading channel with partial-band interference has been derived and the error rate has been evaluated to show in figures as a function of signal to noise ratio, signal to interference ratio, fading figure, repeated number, partial-band interference fraction and power correlation coefficient between signal and interference. In this paper, we assumed that repeated diversity technique is used in transmitter against fading occurred in mobile radio channel. By comparing the error rate performance in diversity against fading and the obtainable degree of improvement of error performance with diversity technique has been found out. From the result, it is known that error rate performance deteriorates more as
becomes small i.e., the partial-band interference gives more effect on error performance than full-band interference. Also when the values of
are small. as depth of fading diversity technique.