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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 19, Issue 12 - Dec 1994
Volume 19, Issue 11 - Nov 1994
Volume 19, Issue 10 - Oct 1994
Volume 19, Issue 9 - Sep 1994
Volume 19, Issue 8 - Aug 1994
Volume 19, Issue 7 - Jul 1994
Volume 19, Issue 6 - Jun 1994
Volume 19, Issue 5 - May 1994
Volume 19, Issue 4 - Apr 1994
Volume 19, Issue 3 - Mar 1994
Volume 19, Issue 2 - Feb 1994
Volume 19, Issue 1 - Jan 1994
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Suppression of Multipath Signals by Applebaum Type Adaptive Array
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 195~201
The potential ability of the Applebaum type adaptive array to suppress the multipath signals is examined. The output Signal-to-Noise Ratio is expressed in terms of (1) the input SNR. (2) relative multipath signal amplitude, and (3) ambient noise when a multipath component is present Computer simulation is done on several performance measures to learn that the performance of the array depends upon the magnitude and the phase of the correlation coefficient. It is also shown that the performance is maximized when the phase of the correlation coefficient is zero degree.
A research on the Network Management Architecture for Flexible Automation
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 202~210
In this paper, the network management system is implemented based on the analysis of reguirements and network operation and management for Flexible Automation. Network management is necessary, which controls and supervises the network resources in the communication network. By means of both analytical methods and queueing model, the delay time distributions due to the increasement of transmission data are obtained and analyzed. The operations of this network management system are certified through the test environments with the network adaptor and softwares for each layer.
The Separation of NTSC Signal Components by Using Adaptive Selection Method of Horizontal and Vertical Filters
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 211~224
In this paper, a multi-level adaptive intraframe method has been proposed to separate the luminance and chominance components in NTSC composite signal. The control signals are generated by detecting the vertical correlation and transition in the horizontal and diagonal directions. The chrominance component is adaptively processed through vertical and horizontal filters according to the control signals and the luminance component is processed by subtracting the chrominance component from the composite video signal. The several filters have been used at the sampling rate of four times the color subcarrier frequency and computer simulation and SVP(Serial Video Processing) system have been introduced to compare the performance of the conventional methods and that of proposed one.
Analysis of Perfectly Conducting Body of Revolution
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 225~230
EFIE`s(Electric Field Integral Equations) are widely used in formulation of electric field problems and these equations are analyzed by several numerical method. In formulation of EFIF by forcing the tangential component of electric field on the perfect conducting body be zero, we can obtain equation with a kernel that has a logarithmic singularities. In this paper, an integral equation is presented which can be used for perfect BOR(Body of Revolution) objects and this can be more simplified for straight wire problem. As examples, monopole antenna which is driven by coaxial cable and scattering problems are considered.
Conceptual Design on the ISDN Service Node for Multiparty Connection Services - Part I. Considerations on the Features and Functions of a Service Node -
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 231~241
To overcome the limit of a point-point connection type service which is common to the ISDN bearer services, a new concept of network element, Service Node, which can provide multiparty connections and control the teleservices on those connections is proposed. This will support conference type multiparty multimedia services among normal ISDN subscribers. In this paper, as a primary study on this concept, we deduce some attributes of the general conference type services and examine the methods and procedures to provide that kind of services through the ISDN. Based on this study, we also define the general requirements and basic structure for the Service Node realization, thus give shape to the concept of it.
Conceptual Design on the ISDN Service Node for Multi-party Connection Services -Part II. A Study on the Control Procedures for the Service Node -
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 242~253
For the implementation of a Service Node, which is proposed in the companion paper to provide multiparty conference type sevices in the ISDN, we define some technical aspects such as connection control, service control procedure and control messages in this paper. Additional connection control procedures for the multiparty connections are annexed to the CCITT Rec. Q.931 and Q.764 for the ISDN subscriber and common channel interoffice signaling. A new set of service control procedures is also established according to the necessary service control functions. The messages for these procedures are formatted using user-to-user signaling parts of Q.931 and Q.763 messages not to affect on the existing signaling system. Some technical requirements of subscriber terminal for the multiparty services are also deduced.
An Optimal Routing Algorithm for Large Data Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 254~265
For solving the optimal routing problem (ORP) in large data networks, and algorithm called the hierarchical aggregation/disaggregation and decomposition/composition gradient project (HAD-GP) algorithm os proposed. As a preliminary work, we improve the performance of the original iterative aggregation/disaggregation GP (IAD-GP) algorithm introduced in . THe A/D concept used in the original IAD-GP algorithm and its modified version naturally fits the hierarchical structure of large data networks and we would expect speed-up in convengence. The proposed HAD-GP algorithm adds a D/C step into the modified IAD-GP algorithm. The HAD-GP algorithm also makes use of the hierarchical-structure topology of large data networks and achieves significant improvement in convergence speed, especially under a distributed environment. The speed-up effects are demonstrated by the numerical implementations comparing the HAD-GP algorithm with the (original and modified) IAD-GP and the ordinary GP (ORD-GP) algorithm.
Korean Lexical Disambiguation Based on Statistical Information
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 265~275
Lexical disambiguation is one of the most basic areas in natural language processing such as speech recognition/synthesis, information retrieval, corpus tagging/ etc. This paper describes a Korean lexical disambiguation mechanism where the disambigution is perfoemed on the basis of the statistical information collected from corpora. In this mechanism, the token tags corresponding to the results of the morphological analysis are used instead of part of speech tags for the purpose of detail disambiguation. The lexical selection function proposed shows considerably high accuracy, since the lexical characteristics of Korean such as concordance of endings or postpositions are well reflected in it. Two disambiguation methods, a unique selection method and a multiple selection method, are provided so that they can be properly according to the application areas.
A Codebook Design for Vector Quantization Using a Neural Network
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 276~283
Using a neural network for vector quantization, we can expect to have better codebook design algorithm for its adaptive process. Also, the designed codebook puts the codewords in order by its self-organizing characteristics, which makes it possible to partially search the codebook for real time process. To exploit these features of the neural network, in this paper, we propose a new codebook design algorithm that modified the KSFM(Kohonen`s Self-organizing Feature Map) and then combines the K-means algorithm. Experimental results show the performance improvment and the ability of the partical seach of the codebook for the real time process.
A Neural Network Algorithm for Adaptively Assigning Channels in Mobile Cellular Systems
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 284~292
In mobile cellular systems, the ever-increasing demand for service continuously necessitaties cell splitting or assignning additional channels to certain base stations. But for most of the presently operative systems, the channels that are already used at some existing base stations are strongly desired not to be changed, giving rise to the Problem of Adaptively Assigning Channels(PAAC). In this paper, we show that the problem can efficiently be solved using the neural network algorithm by exploiting the special feature of the PAAC.
A Design of Channel Models for the ISDN Subscriber Loops
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 293~305
In this paper the efficient channel models of the subscriber loops for the ISDN U-interface digital transmission are presented. Several configuration medels of the loop network are adopted from the CCITT recommendations, and various parameters specifying the physical dimensions are determined in accordance with the measurements of the loop characteristics of Korea. A typical loop interfacing circuit is applied at both ends of the loops and the overall transmissing circuit model is obtained. Based on this circuit model of transmission. 3 types of signal path models, related to transmission, echo, and near end crosstalk noise are defined and their transfer function are respectively derived as the channel models. As examples of the proposed channel models, numerical calculation has been performed for some loop configuration models and the channel responses are investigation in both domains of frequency and time. It is shown that various changes of the loop characteristics can well be explained in terms of the proposed models. And these models can efficiently be used for the simulation of the digital transmission over the subscriber loop.
Multi-Channel TDM Protocol based on Traffic Locality
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 306~321
Since TDM protocol can be easily implemented and show high throughput at heavy load, the researches on the multi-channel high-speed network based on TDM access control have been getting more attention than ever. TDM type multi-channel network, however, has disadvantages of excessive delay at light load and inadaptibility to traffic skewing. In this paper, we proposed a new multi-channel TDM structure, time slots are allocated proportional to the traffic flow pattern among the nodes. thus delay and throughput performance are improved. Design principles of TDM frame are discussed considering traffic locality and the number of available channels. Approximate analytic models for delay evaluation are developed and verified by simulations.
A Study on Modeling of Protocol for Basic Call Process SIB in Advanced Intelligent Network
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 322~330
SIBs(Service Independent Building block) are defined in CCITT advanced intelligent network concept model for supporting various services in the future. This paper describes the protocol modeling and verification for basic call process SIB. For modeling, we use Petri Net and verify this modeling by analyzing reachability tree of Petri Net. Results of this paper should be used for design and implementation of basic call process SIB.
E-Polarized Reflection Coefficient by a Tapered Resistive Strip Grating with Zero Resistivity at Strip-Edges
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 331~337
The scatting problem by E-polarized plane wave with obique incidence on a tapered resistive strip grating with zero resistivity(perfectly conducting) at strip-edges is analyzed by the method of moments in the spectral domain. Then the induced surface current density on the strip is expanded in a series of Chebyshev polynomials of the second kind. The expasion coefficients are calculated numerically in the spectral domain, the numerical results of the geometric-optical reflection coefficient for the tapered resistivity in this paper are compared with those for the existing uniform resistivity. And the position of sharp variation points in the magnitude of the geometric-optical reflection coefficient can be moved by varying the incident angle and the strip spacing, It is found out that these sparp variation points are due to the transition of higher mode between the propagation mode and the evanescent mode.
A generalization of Price's theorem with constrained non-Gaussian inputs
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 338~344
Price`s theorem is generalized for general zero memory nonlinear function when input are drawn from a sum, called the constrained non-Gaussian, of two or more mutually independent processes of which the first is the Gaussian. An example is given to illustrate the applicability of the generalization.
A Study on Performance Analysis of High Resolution DOA Method based on MUSIC
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 345~353
This paper proposes a high resolution direction finding method, which is so called the 'averaged MUSIC'. This method uses a new sample array covariance matrix that consists of diagonal components obtained by taking averages of the diagonal component values of the sample covariance matrix for the MUSIC. This paper also shows that the proposed method performs higher resolced direction-of-arrival estimation than the MUSIC in such cases as low signal-to-noise ratio, closed signal sources, and limited number of sensors, based on the statistical analysis
A Study on the Voice Traffic Efficiency and Buffer Management by Priority Control in ATM Multiplexer
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 354~363
This paper describes the method that voice traffic is served efficiently in BISDN. Voice is divided into talkspurt and silent period, and it is possible to transmit olny talksurt by the speech activity detection. This paper described the voice traffic control algorithm in the ATM network where cell discarding method is applied to the embedded ADPCM voice data. For traffic control, the cell discarding was used over low priority cells when it overflows the queue threshold. To estimate the efficiency of traffic control algorithm, the computer simuation was performed with cell loss probability, queue length and mean delay as performance parameters. The embedded ADPCM voice coding and cell disscarding resulted in improving the voice cell traffic efficiency and the dynamic control over network congestion.
Theoretical Study on the Radiation Pattern of Cross-type 5-patch Rectangular Microstrip Array Antenna
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 364~372
Theoretical method for analyzing the radiation pattern of cross-type 5-patch rectangular microstrip antenna is presented. The equivalent circuit of the array antenna is represented by the conventional transmission line model and the radiation admittance derived from the equivalent circuit of the slitted parallel-plate waveguide filled with a dielectric. The calculated results for the radiation pattern are compared with the measured values.
A Study on the Adaptive Method for Extracting Optimum Features of Speech Signal
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 373~380
In this paper, we proposed a method of extracting optimum features of speech signal to adjust signal level. For extracting features of speech signal we used FRLS(Fast Recursive Least Square) algorithm, we adjusted each frames of equal to constant level, and extracted optimum features of speech signal by using equalized autocorrelation function proposed in this paper.
A Study on the Performance Analysis for Partial Buffer Sharing Priority Mechanism with Two Thresholds
The Journal of Korean Institute of Communications and Information Sciences, volume 19, issue 2, 1994, Pages 381~389
In the communication network, multimedia service such as high quality voice, high speed data, image etc. will be added to the existing service. This service generates new requirements for the communication networks. The priority control mechanism can be used to control multimedia traffics generated by many communication systems. The priority mechanism which assigns prioirities to generated cells according to service quality is one of the traffic control. The priority assignment can be divided by priority criterion for each traffic characteristics such as loss sensitivity and delay sensitivity. In this paper, we alnalyzed the partial buffur sharing (PBS) mechani느 as a traffic control reducing the cell loss, and proposed analysis method. We analyzed the PBS mechanism using classical approach as a Markov chain. In order to validata proposed analysis method, simulation is performed using simulation package SIMSCRIPT 11.5. From this results, we confirmed that proposed analysis method can be verified. Also, we presented cell loss probability of ATM network when this results are to be applied to ATM networks.