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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Institute of Information and Communication Engineering
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Journal DOI :
The Korean Institute of Information and Commucation Engineering
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Volume & Issues
Volume 2, Issue 4 - Dec 1998
Volume 2, Issue 3 - Sep 1998
Volume 2, Issue 2 - Jun 1998
Volume 2, Issue 1 - Mar 1998
Selecting the target year
Development of Real-time Service Primitive in Message Handling System Supporting Desk-top Conferencing System
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 169~180
This research presents development of real-time service primitive in MHS(Message Hanling system) supporting desk-top conferencing system. Desk-top conferencing system is one of the real-time GC(Group Communication) services. The complexity of modem society has led to the consequent need for real-time GC between a number of people in order to jointly handle tasks in business, government and other forms of organization. Despite the many different form of desk-top conferencing systems developed to date, there are still few systems in widespred no. One of the biggest hurdle preventing the widespred adoption of real-time GC is the lack of agreement on user-friendly interchange environments. In distributed office environments, the MHS is one of the most widely used service for information interchange. It is a standard of electronic mail system which is concerned mostly with asynchronous exchange of short notes. It is clear that additional functions on MHS are necessary in order to allow users to properly process their real-time group messages and provide them with important facilities as a communication infrastructure for real-time GC.
Multiplexing Structure and Buffer Control in an ATM Switching System
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 181~186
This paper presents multiplexing structures to provide various subscriber interfaces in an ATM switching system with a high speed internal link, and analyzes the schemes in terms of a mean cell delay and a buffer sin. And we proposed a buffer management strategy to minimize a cell loss and accommodate new ATM transfer capabilities.
The design and implementation of transport protocol stack for multipoint communication services
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 187~195
We developed the conferencing system based on the conference service model which is defined in ITU-T T. 120 series standard. Our conferencing service system is operated over the local area network. The NetMeeting of Microsoft corporation is used as a terminal and the MCU is developed by ourselves. In this paper, we described the design and implementation method of transport protocol stack supporting Multipoint Communication Service (MCS). Also, we described the occurred problem during the interoperability test between MCU and NetMeeting. And then we suggested their solution.
Analysis of microstrip patch array antenna characteristics using finite difference time domain algorithm
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 197~205
The purpose of this paper is to analyze the electromagnetic field characteristics of array antenna with the finite difference-time domain algorithm. Finite difference equations of Maxwell's equations are defined in cylindrical coordinate systems. To simulate the unbounded problem like a free space, the Mur's absorbing boundary condition is also used. After modeling the array antenna with the grid structure, the transient response of the field distribution is depicted in the time domain.
A Study on Policy for Telecommunication Network in Future
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 207~214
This paper is focused on the desirable schemes of policy on future telecommunication Network. In the scope and method of this study there must invalve following two items: 1) the first item is about the telecommunication Network System. 2) the second item is about the telecommunication network policy in future. The results of study is as follow: 1) an establishment of middle-long range planning for the telecommunication network 2) an establishment of the organization of society for system telecommunication network.
A study of the Telecommunication Technique Policy in ]Korea : in case social changes
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 215~222
This study is focused on the developing of the telecommunication technique for the analysis on the social changes. We predict, the role increase greatly important foundational society structure of coming twenty-one century. In the scope and method of this study there must invalve following five items: constructed global society, developing economic, limit resources, change personal behavior, security of living, This problem to find a solution to the change of telecommunication technique policy in Korea.
The power regulation of a High-Frequency Induction Heating System with time variance load using a neural fuzzy controller
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 223~230
This paper describes a phase-shift pulse-width modulation and pulse-frequency modulation series resonant high-frequency inverter using IGBT(Insulated-Gated Bipolar Transistor) for the power control of high-frequency induction heating using neuro-fuzzy, which is practically applied for 20KHz~500KHz induction-heating and melting power supply in industrial fields. The adaptive frequency tracking based phase-shifting PWM(Pulse-Width Modulation) regulation scheme is presented in order to minimize switching losses. The trially-produced breadboards using IGBT are successfully demonstrated and discussed.
Speed Control of Permanent Magnet Synchronous Motor Using PI Auto-tuning Method
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 231~239
In this paper, we designed a current controlling servo system for speed control of a PMSM. In existing auto-tuning methods for PI controller parameters, the output response is delayed and the overshoot is generated. By solving these existing problems in this paper, a new PI auto-tuning method is applied to the speed controller for fast-response and reduced overshoot. PMSM servo systems offer a great advantage in unmanned factories where a great number of servo motors are employed, because of its easy maintenance characteristics and controllability. The implemented servo system is composed of absolute position detecting circuits of a rotor, a new auto-tuning PI control algorithm, a speed controller by using DSP, and power driving section. The proposed servo system is verified for it's practical availability by considering experimental results.
Measurement of low level sound noise using cross spectrum method
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 241~248
The accurate measurement of the room sound level is required in environment noise control. However, it has been found that the measurement system noise always corrupts the actual noise from the sound source. In this study, a new sound level measurement technique in which the system noise is eliminated from the measured signal by the cross spectrum method, is proposed. The received signals of two measuring microphones are recorded to DAT through the pre-amplifier and digitized by A/D converter. The cross spectrum calculated from the digitized signals gives the accurate sound level since the system noise is uncorrelated with the sound source noise which we want to measure. The performance of the proposed technique is verified experimentally to be effective and the technique is found to be economic since the low cost general purpose microphone could be used in this technique.
Performance Analysis of Pilot Symbol Assisted QAM (PSA-QAM) with Power Amplifiers Nonlinear Compensation Technique
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 249~258
In land mobile communication, very extensive studies on pilot symbol assisted modulation (PSAM) have been made on fading compensation. This paper analyzes the effect of power amplifier nonlinearity on PSA-QAM with maximal ratio combining space diversity. In practical PSAM, information on fading is obtained through interpolation of the pilot symbols. We employed the interpolation filter which could minimize the average power of error and analyzed effects on the system performance of the number of filter taps, period of the pilot symbol frame, and the Doppler frequency. Nonlinear power amplifiers of class AB, B, and C were incorporated in the system models and their AM/AM and AM/PM characteristics were taken into account in the performance analysis. We showed the performance variations according to the types of the nonlinear power amplifiers in the AWGN and Rayleigh fading channels using nonlinear compensation technique, Cartesian Feedback Loop (CFB).
Implementation of the VHF EPIRB using the technique of Digital Selective Calling
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 259~266
406MHz and INMARSAT-E EPIRB facility transmits the distress alerts by the relay of the polar-satellites and INTELSAT, but may cause the probability of delayed transmission because of the orbital period and not compliance with the implementation of GMDSS rules for small ships in A1 area.. Digital Selective Calling forms a critical part of the terrestrial elements of the GMDSS system and ensures the reliability and the efficiency in the system. In this paper, we suggests that new DSC EPIRB in the VHF band to overcome this defect for small ships in A1 area, and analyze the ITU-R recommendations and technical characteristics, design and implement the algorithm of calling sequences, frequency synthesizer for the RF signal and FSK moulation signals.
The design of a charge pump for the high speed operation of PLL circuits
Journal of the Korea Institute of Information and Communication Engineering, volume 2, issue 2, 1998, Pages 267~273
In this paper, we designed a charge pump with a differential current switching structure and it was made of a MESFET with high speed switching Property compared with CMOSFETs. The charge pump with a differential current switching structure is analyzed about operating property of circuit in high frequency band. Also we propose a method on it's characteristics estimation. The designed circuit is simulated by HSPICE simulator, and in view of the results we think that the charge pump of this study can be used in circuits of 1 GHZ frequency band grade.