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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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Journal DOI :
The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 16, Issue 12 - Dec 1991
Volume 16, Issue 11 - Nov 1991
Volume 16, Issue 10 - Oct 1991
Volume 16, Issue 9 - Sep 1991
Volume 16, Issue 8 - Aug 1991
Volume 16, Issue 7 - Jul 1991
Volume 16, Issue 6 - Jun 1991
Volume 16, Issue 5 - May 1991
Volume 16, Issue 4 - Apr 1991
Volume 16, Issue 3 - Mar 1991
Volume 16, Issue 2 - Feb 1991
Volume 16, Issue 1 - Jan 1991
Selecting the target year
국제 VAN의 동향과 과제
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 291~300
As IVAN(International VAN) becomes a major topic on the table of Korea U.S. Telecommunications Consultation, public concern to this area is growing. IVAN service has been dedicated to the business domain of PTT or public telecommunications operator, and its development has been so limited as well. However, the situation is being changed and IVAN liberalization is considered to be essential not to isolate itself from globilized networks. Seeing the fact UR is challengnign ITU in facilitating the trade of telecommunications services, the worldwide trend of liberalization is apparant. It should be addressed that a clear policy anouncement is necessary with regard to the liberalization of IVAN. The purpose of this paper is to conduct case studies of IVAN agreements and to draw policy oriented issues.
A Study on the Digital Demodulation Circuit Design and its Performance Evaluation of Radio Data Receiver System
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 301~308
In this paper, we have proposed a demodulation circuit of radio data receiver system and calculated the error probability of the digital transmitted signal corrupted under noise environment. And we have evaluated the error performance of the proposed system. The designed demodulation circuits have been implemented by using the general random logic and PLL circuits, which can be possible for the integrated circuit design of the radio data receiver system. In addition calculation of bit error rate in recovered digital signal has been accomplished ans we have confirmed that the proposed system hsa the equivalent performance with already existing ones.
Improvement on the Speed-Response of DC Motor Using Bond Graph Modeling Method
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 309~318
In this paper, the integrator used to reduce the error between the reference signal and response, and DC motor are constructed by bond graph. Then the model following servo controller which have the high adaptation with respect to inertia, disturbance and/or load variation in the speed control system of DC motor is designed by the bond graph, and then the usefullness of this modeling method is confirmed in operating analysis and design on controller.
A Detection Scheme for Known Signals in Signal-Dependent Noise Using Rank Statistics
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 319~325
A nonparametric detection scheme which uses rank statistics for detection of known signals is considered in a special case of a generalized observation model. Specifically locally optimum rank detectors for detection of known deterministic singals in a singnal-dependent noise model are derived, and compared to those derived for the purely-additive noise model. Examples of the score functions are given, which constitutes the test statistics of the locally optimum rank detectors.
An Optical Asynchronous Transfer Mode(ATM) Switching System Using Free Space Optics and an Output Buffer Memory
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 326~334
We propose an optical Asynchronous Transfer Mode(ATM) switching system using free-space optics and an output buffer memory. The distributor system in the switching fabric was analyzed using the Huygens-Fresnel principle and lens transformation. For monochromatic illumination, a pattern similar to the Fourier transform of the input distribution was observed across the output plane. A spatially broadened intensity distribution across the the output plane can be expected when the system is illminated with a partially coherent, quasimonochromatic beam. Spatially coherent pulses as short as 100fs can propagate through the distributor without severe spatial broadening.
An Analysis of EMI Characteristics and the Induced Load Current on th Transmission Line Being Close to the Rectangular Horn Antenna
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 335~341
We derive the radiation field equation at the naar field region to analyse EMI by the rectangular horn antenna. The EMI loadk current calculated from the load current induced on the transmission line being close to the rectangular horn antenna using the field theory and the transmission line theory. We find the conditions minimizing the EMI from the load current transfer function of distance, frequency and impedances at sending and receiving end. The smaller sending end impedance, the larger EMI load current and the larger sending impedance, the smaller EMI load current.
Tracking Controller Design Using Delayed Output Feedback For Systems With Stiff Nonlinearities
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 342~349
In this paper, a method is presented for designing a tracking and disturbance rejecting controller for a nonlinear control system in which approximate linearization is not applicable due to a s stiff nonlinearity. Only the measurable variables are used for the controller synthesis. The system is augmented by a compensator at the output side for the tracking and disturbance rejection. An output delayed feedback controller is designed for the augmented system without nonlinearity. Then the feedback parameters are adjusted by describing function method to overcome the limit cycle due to the nonlinearity.
Speech Recognition and Its Learning by Neural Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 350~357
A speech recognition system based on a neural network, which can be used for telephon number services was tested. Because in Korea two different cardinal number systems, a koreanic one and a sinokoreanic one, are in use, it is necessary that the used systems is able to recognize 22 discret words. The structure of the neural network used had two layers, also a structure with 3 layers, one hidden layreformed of each 11, 22 and 44 hidden units was tested. During the learning phase of the system the so called BP-algorithm (back propagation) was applied. The process of learning can e influenced by using a different learning factor and also by the method of learning(for instance random or cycle). The optimal rate of speaker independent recognition by using a 2 layer neural network was 96%. A drop of recognition was observed by overtraining. This phenomen appeared more clearly if a 3 layer neural network was used. These phenomens are described in this paper in more detail. Especially the influence of the construction of the neural network and the several states during the learning phase are examined.
A Remote Data Access Interface Model Using the Monitor IPC Mechanism
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 358~381
In this paper, we construct a remote data access interface model using the IPC mechanism based on the monitor concept. A general purpose IPC mechanism which can be used to implement arbitrary forms of communications control over distributed processes in a network environment is developed as a basis to build the framework for the model. The interface model and synchronization mechanisms are presented for providing application processes with remote data access capability using the above IPC mechanism.
A Distributed Processes Communication Control Mechanism Based on Monitor Concepts Implemented Through Simulation Using Semaphore
The Journal of Korean Institute of Communications and Information Sciences, volume 16, issue 4, 1991, Pages 382~395
A general purpose distributed processes communication control mechanism is a typical approach used for synchronizing concurrent processes involved in communication. The mechanism can provide a framework on which the layered communication architectures and protocols are efficiently implemented. The mechanism is realized under restricted environment where monitor facility is not available by means of simulation using semaphore.