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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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The Korean Institute of Information and Commucation Engineering
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Volume & Issues
Volume 4, Issue 5 - Dec 2000
Volume 4, Issue 4 - Nov 2000
Volume 4, Issue 3 - Sep 2000
Volume 4, Issue 2 - Jun 2000
Volume 4, Issue 1 - Mar 2000
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Trellis Coded Spread Spectrum with the multiple symbol detection
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 517~526
In this paper, we propose the trellis coded spread spectrum communication system with one channel signal selection of the subset by the PN code. This paper proposes the Viterbi decoder that have the squared Euclidean distance of the order phase difference as well as 1st order phase difference as the branch metrics by using the multiple symbol detection method. TCM method was developed to overcome limited power and bandwidth efficiently in digital communication. we multiply one of convolution code's output data to PN code for applying TCM to the spread spectrum. We investigated the performance of the direct sequence/spread spectrum communication system with trellis coded modulation. In this system, we could improved the coding gain in the spread spectrum.
Implementation of Down Converter for Ku-Band Application
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 527~536
This paper discusses the design of self-oscillating mixer type low noise down converter using the microwave field effect transistor. The mixer is consists of local oscillator in which high stability dielectric resonator and band pass filter to get rid of spurious oscillation at intermediate frequency stage. The microstrip antenna was integrated in the same substrate which generate 12.3GHz and low noise amplifier was also added after antenna using 3 stage of high electron mobility transistors. The output frequency from the local oscillator was chosen as 11.3GHz for the Ku-band application. The measured phase noise was -804dBc/Hz at 100kHz offset frequency, and the gain was 7～12dB in frequency range from 12.0GHz to 12.7GHz. The noise figure at intermediate frequency stage was 64H. The designed model shows less conversion loss than previous diode type mixer. The proposed mixer can be used in digital satellite broadcasting and communication system and expected to use in next generation low noise block design.
Performance Analysis of Bandwidth Allocation Scheme using POBP Method in ATM Networks.
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 537~548
An Approximate algorithm for the analysis of the n heterogeneous IBP/D/l queuing model
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 549~555
We propose an approximate algorithm to analyze the queuing system with n bursty and heterogeneous arrival processes. Each input process is modeled by Interrupted Bernoulli Process(IBP). We approximate N arrival processes by a single state variable and subsequently simplify the transition probability matrix of the Markov chain associated with these N arrival processes. Using this single state variable of arrival processes, we describe the state of the queuing system and analyze the system numerically with the reduced transition probability matrix. We compute the queue length distribution, the delay distribution, and the loss probability. Comparisons with simulation data show that the approximation algorithm has a good accuracy.
Design of Microstrip Band-Pass filters Using Cross-Coupled Hairpin Resonators
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 557~564
A microstrip band-pass filter using cross-coupled resonators is designed and studied experimentally. The cross-coupled microstrip hairpin resonator filters exhibit ripples in both passband and stopband. These ripples can improve both frequency selectivity and insertion loss. The cross-coupled filters are not only simple and compact in configuration, but also have great flexibility to form filters into a variety of size. In this paper, a microstrip band-pass filter using cross-coupled resonators is designed at the center frequency of 1.8GHz with bandwidth of 5.0% using Ensemble software. The experimental results show that the bandwidth is about 4.53% at 1.8GHz.
Design of a Interdigital Microstrip Bandpass Filter
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 565~573
In this paper, a interdigital microstrip bandpass filter is designed. A interdigital microstrip bandpass filter has many advantages such as insertion return loss, lower return loss, higher frequency selectivity and smaller in size in comparison with the conventional coupled line filter. A interdigital microstrip bandpass filter consists of quasi TEM-mode strip line resonators between parallel ground plant. Each resonator element is a quarter wavelength long of the center frequency and is short circuited at one end and open circuited at the other end. In the filter design, Ensemble software is used. Experimental results show that the bandwidth of interdigital microstrip bandpass filter is 2.52GHz, insertion loss is -1.8dB and return loss is -17.0dB at 11.20Hz.
A Development of Pulse Oximeter module for Measurement of
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 575~583
Pulse oximetry is a well established non-invasive optical technique for monitoring the
during anaesthesia, recovery and intensive care. Pulse oximeters determine the oxygen saturation level of blood by measuring the light absorption of arterial blood. In the measurement of the hemoglobin oxygen saturation, conventional method has required the technique of filtering of remove the noise, and of complex signal processing algorithm. So much time have been required to signal processing. In this research, we separate AC signal and DC signal in the stage of signal detection. Therefore we simplify the calculation algorithm for
. The implemented system have the high performance such an accuracy and a processing time than the traditional method.
Moving Path Following of Autonomous Mobile Robot using Neural Network
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 585~594
The exact path following of an autonomous mobile robot in a factory and an unreliable environment has many disadvantages in case of a classical control algorithm. In this paper, a neural network control approach based on an error back propagation algorithm is proposed for controlling a mobile robot to follow a line installed on the road. Since not only the three recognized informations from three sensors attached on a mobile robot but also the ten detailed informations in non recognition area are learned with input patterns, a mobile robot moves smoothly an installed line in spite of non perception space. The mobile robot has an effect of error minimization with a short time till a destination. To test an effectiveness of the proposed controller, the two motor velocity changes which is affected from a moving angle change of a mobile robot are simulated with computer.
Comparative Analysis of TOA and TDOA method for position estimation of mobile station
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 595~602
This paper is aimed at developing an location tracking system of mobile station based on currently available mobile communication network or mobile Phone and PCS(Personal Communication System). When the location tracking of mobile stations is in services, Emergency-119, all of crime investigation, effective urban traffic management and the safety protection of Alzheimer＇s patients can be available. In order to track the location of the mobile and base station, assumption in this paper is to use the statistic characteristics of LOS when modeling the standard noise in case that radio path is LNOS environment. The standard variation of the standard noise is
. First, location is estimated by the positioning algorithms of TOA and TDOA and compared each other. Second, after canceling the standard noise by Kalman filter, location is estimated by the above two positioning algorithms. Finally, the location by the Kalman filter and two positioning algorithms is estimated by smoothing method. As a result, 2 dimensional average location error is imvoved by 51.2m in TOA and 34.8m in TDOA when Kalman filer and two positioning algorithms are used, compared with the two positioning algorithm used. And there is 3 more meter improvement after smoothing than Kalman filer and two positioning algorithms used.
Design of the Combined Direct and Indirect Adaptive Neural Controller Using Fuzzy Rule
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 603~610
In this paper, the direct and indirect adaptive controller are combined based on the Lyapunov synthesis approach. The Proposed controller is constructed from RBF Neural Network and weighting parameters are adjusted on-line according to some adaptation law. In this scheme, fuzzy IF-THEN rules are used to decide the combined weighting factor. In the results, proposed controller has the main advantages of both the direct adaptive controller and the indirect adaptive controller. The effectiveness of the proposed control scheme is demonstrated through simulation results of control for one-link rigid robotics manipulator.
Adaptive Fuzzy Inference Algorithm for Shape Classification
Kim, Yoon-Ho ; Ryu, Kwang-Ryol ;
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 611~618
This paper presents a shape classification method of dynamic image based on adaptive fuzzy inference. It describes the design scheme of fuzzy inference algorithm which makes it suitable for low speed systems such as conveyor, uninhabited transportation. In the first Discrete Wavelet Transform(DWT) is utilized to extract the motion vector in a sequential images. This approach provides a mechanism to simple but robust information which is desirable when dealing with an unknown environment. By using feature parameters of moving object, fuzzy if - then rule which can be able to adapt the variation of circumstances is devised. Then applying the implication function, shape classification processes are performed. Experimental results are presented to testify the performance and applicability of the proposed algorithm
The design of the expanded I-PD Controller with the Neuro-precompensator
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 619~625
A many control techniques have been proposed in order to improve the control performance of the discrete-time domain control system. In the position control system, the output of a controller is generally used as the input of a plant but the undesired noise is included in the output of a controller. Therefore there is a need to used a precompensator for rejecting the undesired noise. In this paper, The expanded I-PD control system with a precompensator is constructed. The precompensator and I-PD controller are designed by a neural network and these coefficients are changed automatically to be a desired response of system when the response characteristic of system is changed under a condition.
A Study on the Polyphase Filter with Micro-ripple and almost Linear phase Characteristic in Pass-band
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 627~633
In this paper, the polyphase filter which has micro ripple characteristic in the passband is proposed. This filter consists of the digital all-pass filter of parallel structure and it is the half-band filter with all zeros in unit circle. To approach easily in designing hardware, we determined the coefficients to the 16bit 1.15 format. To evaluate the performance of this filter, we analyzed the phase characteristic in each branch and each filter with small coefficients. Also, we simulated the phase characteristic of passband and stopband, group delay. As the result, we obtained the micro ripple characteristic and linear phase in the passband.
Performance Analysis of WATM-OFDM/l6QAM System in Frequency Selective Rayleigh Fading Channel
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 635~642
We have been derived theoretically the SER's and CLP's of Wireless ATM (WATM) cells employing an OFDM/16QAM modulation scheme in wireless channel modeled as a frequency selective Rayleigh fading channel. The amount of the performance improvement of WATM- OFDM/16QAM systems adopting various coding techniques has been evaluated. In frequency selective Rayleigh fading channel, considering CLP :
as a criterion, it is observed that the performance improvement of about 14 dB is obtained in terms of
by employing an OFDM scheme. It is also confirmed that convolutional coding technique gives better performance than the other coding techniques. Especially, when the convolutional codes are adopted to WATM-OFDM/16QAM systems, voice transmission services are sufficiently available with 5 dB of
Performance Analysis of OFDM/QPSK System in Frequency Selective Rayleigh Fading Channel with Impulsive Noise
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 643~652
In this paper, we analyze the BER performance of OFDM/QPSK system in frequency selective Rayleigh fading channel with impulsive noise and improve its performance by adopting convolutional coding. When the channel delay time is shorter than the guard band, the OFDM/QPSK system shows a good BER performance while, when the channel delay time becomes longer than the guard band, its BER performance is abruptly degraded. Moreover, when the transmitted signal is contaminated by a strong impulsive noise in the channel, the BER performance falls to about
. Also, without channel coding technique, the system doesn't meet even the voice service requirement while it meets the data service requirement with convolutional coding in frequency selective Rayleigh fading channel with impulsive noise.
On the Performance of Interference Excision Scheme using Multiple Adaptive Filter Banks in Spread Spectrum Communication Systems
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 653~660
In this paper, an adaptive interference excision scheme with multiple adaptive filter bank using an adaptive algorithm is proposed. This scheme suppresses interference in the wavelet packet transform domain for the direct spread spectrum communication systems. Using the Monte-Carlo simulation, we analyze the performance of the direct spread spectrum communication systems with this excision scheme using LMS and RLS adaptive algorithms in AWGN and interference channel.
A Single-User ]deceiver using Pilot-Assisted Channel Equalizer for DS-CDMA Downlink
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 661~669
DS-CDMA downlink distinguishes actual user by orthogonal spreading codes ,but its orthogonality may be lost by the multiple access interference(MAI) caused by the multipath channel. Therefore in this paper, we proposed the single-user receiver, which use linear channel equalizer to eliminate the interference due to multipath channel and to recover orthogonality and then use code-matched filter to detect transmitted data. Unlike existing research, which mainly assumed ideal channel information, we use pilot channel assisted methods that is a kind of transmission of a parallel reference method to estimate the channel coefficients. Especially we use guard symbols which are inserted periodically to estimate channel coefficients exactly without interference from user signal. The results show that we accepted an approximately ideal channel information and achieved excellent performance improvement using proposed receiver compared with the conventional receiver especially user populations are high.
A Study on the Implementation of Cryptography Scheme for Secure Data Transmission on WWW
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 671~679
In this study, the messages sent at application layer are encrypted by using RSA Public Keys before sending. Then we developed the information security system devised for the secure WWW data transmission by extending the functions of the Netscape browser and by using application programs such as Java applications and by using the plug-in methods. Not only can these technologies reduce and make it easier to perform key management or encryption transmission process, but they can also reduce the processing time of encryption correspondence.
A Study on the Optimized Representation for Data and Control Flow Information
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 681~687
Ideograph is a truly unifies data and procedural dependencies, Ideograph can be used to assist various program optimization, such as common expression elimination, code motion, constant folding etc. In this paper, we design and implementation of the optimized abstract syntax tree using Ideograph. Ideograph has control flow information and data flow information for source program. So we use a Ideograph in order to produce a optimized Ideograph with control flow information and data flow information.
Sliding Mode Speed Controller for the BLDC Motor having New Switching Surface
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 689~696
In this paper, an improved method is proposed to eliminate the chattering for Sliding Mode Controller. The differential-calculus of a switching function is converged to a particular constant or the proportional term so that the chattering in transient state is eliminated in the conventional method. However, by using the improved method, it is converged to its proportional-integral term so that the chattering is eliminated in transient state and steady state both. The computer simulation for brushless DC motor speed controller is used to compare the improved method with the conventional method and to verify the useful effect of the method in this paper.
A Study on the Temperature dependent Impact ionization for GaAs using the Full Band Monte Carlo Method
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 697~703
As device dimensions are lastly scaled down, impact ionization(I.I.) events are very important to analyze hot carrier transport in high energy region, and the exact model of impact ionization is demanded on device simulation. We calculate full band model by empirical pseudopotential method and the impact ionization rate is derived from modified Keldysh formula. We calculate impact ionization coefficients by full band Monte Carlo simulator to investigate temperature dependent characteristics of impact ionization for GaAs as a function of field. Resultly impact ionization coefficients are in good agreement with experimental values at look. We how energy is increasing along increasing the field, while energy is decreasing along increasing the temperature since the phonon scattering rates for emission mode are very high at high temperature. The logarithmic fitting function of impact ionization coefficients is described as a second orders function of temperature and field. The residuals of the logarithmic fitting function are mostly within 5%. We Dow, therefore, the logarithm of impact ionization coefficients has quadratic dependence on temperature, and we can save time of calculating the temperature dependent impact ionization coefncients as a function of field.
Fabrication of oxide semiconductor thin film gas sensor array
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 705~711
A thin film oxide semiconductor micro gas sensor array which shows only 60 mW of power consumption at an operating temperature of
has been fabricated using microfabrication and micromachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double-layer structure of
thick phosphosilicate glass (PSG) prepared by low-pressure chemical-vapor deposition (LPCVD) and atmospheric-pressure chemical-vapor deposition (APCVD), respectively. The sensor array consists of such thin film oxide semiconductor sensing materials as 1 wt.% Pd-doped
/ and ZnO. Baseline resistances of the four sensing materials were found to be stable after the aging for three days at
. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials.
Structural properties of GeSi/Si heterojunction compound semiconductor films by using SPE
Journal of the Korea Institute of Information and Communication Engineering, volume 4, issue 3, 2000, Pages 713~719
In order to Prepare the
(111) heterosructure by solid phase epitaxy (SPE), about 1000A of Au and about 1000A Ge were sequentially deposited on the Si(111) substrate. The resulting Ge/Au/Si(111) samples were isochronically annealed in the high vacuum condition. The behaviors of Au and Ge during thermal annealing and the structural Properties of
films were characterized by Auger electron spectroscopy (AES), X-ray diffraction (XRD) and high resolution transmission electron microscopy (TEM). The a-Ge/Au/Si(111) structure was converted to the Au/GeSi/Si(111) structure. Defects such as stacking faults, point defects and dislocations were found at the GeXSil-X(111) interface, but the film was grown epitaxially with the matching face relationship of
(111)/Si(111). Twin crystals were also found in the