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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 18, Issue 12 - Dec 1993
Volume 18, Issue 11 - Nov 1993
Volume 18, Issue 10 - Oct 1993
Volume 18, Issue 9 - Sep 1993
Volume 18, Issue 8 - Aug 1993
Volume 18, Issue 7 - Jul 1993
Volume 18, Issue 6 - Jun 1993
Volume 18, Issue 5 - May 1993
Volume 18, Issue 4 - Apr 1993
Volume 18, Issue 3 - Mar 1993
Volume 18, Issue 2 - Feb 1993
Volume 18, Issue 1 - Jan 1993
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Design of the Digital Waveform Filter Using the Memory in the RDS Encoder
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 611~618
A common requirement in digital communication systems is the generation of prescribed shape. The purpose of this paper is implement an efficient digital waveform filter by using the look-up table in the RDS(Radio Data System) encoder. And it has been shown that transmitted data can be recovered without an error. In order to implement an efficient waveform filter, the control algorithm is designed. For the purpose of composing an IC, the digital waveform filter is implemented by using the discrete elements. Moreover in this paper it has been proved that the proposed digital waveform filter can be applied to the RDS encoder.
A Study on Design of a High Level Hardware Description Language
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 619~633
A new High level hardware Description Language, ASPHODEL(Algorithm Synthesis Pascal Hardware for Optimal Design and Efficient Language), and its algorithm compiler for high level synthesis are described in this paper. The new HDL, appropriated to the description of algorithmic level and lower, models VLSI circuits as an abstracted block which is consisted of input/output ports and hierachical processors to control VLSI complexities with efficiency. Also, in order to improve the descriptive power, popular Pascal programming language is modified to build ASPHODEL syntax rules. ASPHODEL algorithm compiler generates an intermediate form through lexical and syntax analysis from ASPHODEL source codes. To show the validation of presented language and its compiler, those are applied to practical design examples.
Trajectory Control of a Robot Manipulator by TDNN Multilayer Neural Network
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 634~642
In this paper a new trajectory control method is proposed for a robot manipulator using a time delay neural network(TDNN) as a feedforward controller with an algorithm to learn inverse dynamics of the manipulator. The TDNN structure has so favorable characteristics that neurons can extract more dynamic information from both present and past input signals and perform more efficient learning. The TDNN neural network receives two normalized inputs, one of which is the reference trajectory signal and the other of which is the error signals from the PD controller. It is proved that the normalized inputs to the TDNN neural network can enhance the learning efficiency of the neural network. The proposed scheme was investigated for the planar robot manipulator with two joints by computer simulation.
ML Frame Synchronization for Gaussian Channel with Co-channel Interference
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 643~649
The problem of locating a periodically inserted frame synchronization pattern in random data for a binary pulse amplitude modulated (PAM) digital communication system over a additive white Gaussian noise(AWGN) channel with co-channel interference is considered. The performance degradation of frame synchronization for the correlation rule due to the presence of co-channel interference is shown. The maximum likelihood(ML) decision rule for the frame synchronization over an AWGN channel with co-channel interference is derived. For the entire range of SNR considered, the ML frame synchronization rule obtains about 1dB signal energy gain over the correlation rule. Specially, the ML rule obtains as much as 2dB gain over the correlation rule when the SNR is greater than 0dB.
Realization and Test of the Transport Layer Protocol
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 650~662
The thesis describes the realization and test of the transport layer operating on the CLNS (Connection Less Network Service) which is specified by ISO 8073 and ADDENDUM 2 protocol. For realization of the transport layer, five modules and interface primitives were definde. This protocol was formally described by SDL (Specification and Description Language) and was programmed in C-language. For verification of the software, protocol tester was implemented and test scenarios were defined. The verification was accomplished based on the test scenarios. Transport Layer software presented in this thesis may be utilized in a real situation with some modifications. Protocol tester presented in this thesis can also be used for verification of other protocol softwares.
A Study on the DCT Image Coding Considering Weber's law
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 663~674
In this paper, a DCT image coding algorithm using the human visual property is proposed. Human visual is relatively sensitive to noise in the darker region, insensitive to noise in the brighter region. This property was proved by Weber's law through psycovisual experiment. Weber's law states that the just noticeable difference (j.n.d.) is proportional to intensity. Therefore, the implication of this observation for image processing is that reducing noise in the darker region is more important than reducing noise in the brighter region. In this proposed coding scheme AC coefficients in the darker region are more finely quantized than those in the brighter region. Results showed that, at low bit rate, the subjective quality of reconstructed images by proposed coding scheme is improved than that of coding scheme without considering human visual property.
Traffic Characteristics of the DQDB-based B-ISDN access network
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 675~684
In this paper, we analyze a traffic control schemes at the interworking unit(IWU) of the IEEE 802.6 DQDB MAN and the B-ISDN, and estimate its performance via computer simulation. We also study traffic management, relaying sublayers for the cases of four service classes defined in the B-ISDN. As for performance criteria, we consider slot waiting time, slot loss rate, and the fairness between DQDB nodes in access networks. We propose a simple control algorithm that decreases the waitint delay at the OWU. With the buffer size of 40 [slots] at the IWU, we have found that the slot loss rate was nearly zero at traffic load below 0.9, and the slot waiting time became less than 15 slot times.
Progressive Image Transmission using LOT/CVQ with HVS Weighting
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 685~694
A progressive image transmission (PIT) scheme based on the classified transform vector quantization (CVQ) technique using the lapped orthogonal transform (LOT) and human visual system (HVS) weighting is proposed in this paper. Conventional block transform coding of images using DCT produces in general undesirable block-artifacts at low bit rates. In this paper, image blocks are transformed using the LOT and classified into four classes based on their structural properties and further divided adaptively into subvectors depending on the LOT coefficient statistics with HVS weighting to improve the reconstructed image quality by adaptive bit allocation. The subvectors are vector quantized and transmitted progressively. Coding tests using computer simulations show that the LOT/CVQ based PIT of images is a effective coding scheme. The results are also compared with those obtained using PIT/DCTVQ. The LOT/CVQ based PIT reduces the block-artifacts significantly.
A Study on Representation of Ada Tasking Execution Time Complexity using ATSN
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 695~707
Marked Petri Net(MPN) is used to analyze communication complexity with respect to the maximum number of concurrently active rendezvous. But, because it cannot represent timed & probability characteristics explicitly, it is not used to analyze the new execution time of complexity with respect to the communication. Thus to effectively analyze that execution time complexity, we propose Ada Tasking Structure Nets (ATSN) introduced restrictive conditions : net reduction rules, execution time, and probability. Finally, we show the powers of analyze of communication complexity with ATSN.
The Design of th GRACE-LB Algorithm for Congestion Control in Broadband ISDN ATM Network
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 708~720
The new preventive control mechanisms for traffic management in BISDN/ATM networks can be divided into Connection Admission Control(CAC), Usage Parameter Control (UPC), and Priority Control. Of these mechanism, Usage Parameter Control continuously monitors the parameters admitted in the network's entry point to guarantee quality of service of connections already admitted. Upon detecting traffic that violates the negotiated parameter, it takes the necessary control measures to prevent congestion. Among these traffic control methods, this paper focuses on the Usage Parameter Control method, and proposes and designs GRACE-LB(Guaranteed Rate Acceptance & Control Element-using Leaky Bucket) which improves upon existing UPC models. GRACE-LB modifies the previous LB model by eliminating the cell buffer, dividing the token Pool into two pools, Long-term pool, Short-term pool, and changing the long-term token generating form using 'Cycle Token' into the same bursty form as the traffic source. Through this, GRACE-LB achieves effective control of the Average Bit Rate(ABR) and burst duration of bursty multimedia traffic which previous LB models found difficult to control. Also, since GRACE-LB can e implemented using only simple operations and there are no cell buffers in it, it has the merit of being easily installed at any place
Multipath Fading Channel Simulation in Urban Mobile Radio Environment
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 721~729
A new channel simulation method for the urban mobile radio communication is proposed based on the Aulin's mathematical model which is suitable for urban areas. The proposed method maintains advantage of Jakes Method which is readily implemented in hardware and simulated well various channel states, and solves the problem that measured power spectrum generated by Jakes method does not agree with practical power spectrum. It has been shown by simulation; that good agreements between measured values generated by the proposed method and theoretical values for autocorrelation, LCR, ADF and power spectrum are obtained and that method can easily produce several independent fading signals.
A Study on Dynamic Formatting Method
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 730~738
This paper proposes a dynamic formatting method for processing large amounts of document in a device independent manner. And it is very useful for cross-referencing among pages in a single document and for presenting multiple pages simultaneously. The method can be applied usefully to hypertext's application such as establishing a link and a cross-reference among pages in a multiple document. We implemented an electronic publishing system of WYSIWYG type using X window system and Motif graphical user interface.
A Study on Digital Temperature Compensated Crystal Oscillator
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 739~745
In mobile communication instruments, realization of the frequency synthesizer with high stabililty in temperature is very important. In order to realize a high stability frequency synthesizer, the oscillator providing for reference frequency must be stabilized in various temperature. In accordance to this requirement, the TCXO using digital method is rrealized in this thesis. The DTCXO consists of temperature sensing part, control part and the VCXO. The frequency stability of the realized DTCXO is 0.94 ppm on average. This is an improved result when compared with the 2.5 ppm of the TCXO using analog method.
A Study on Design and Implementatio of Script Management of Script Management Function
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 746~756
Delegation model supports effective and highly reliable network management. It reduces traffic overhead caused by transmission of management informations. In this model, management scripts can be composed by the designers of managers, these are delegated to agents. Delegation models support effective distribution of management functions among managers and agents. Therefore, various functions are needed to create and delegate management scripts. In this paper, we design simple script language and implement script interpreter for efficient network management. And, we define script management functions and services. Moreover, we present manager/agent models and algorithms for script management. As an implementation environment, the ISODE services are ported. The methods employed for the implementation are also described.
A Study on the Extraction of Knowledge for Image Understanding
The Journal of Korean Institute of Communications and Information Sciences, volume 18, issue 5, 1993, Pages 757~772
This paper describes the knowledge extraction for image understanding in knowledge based system. The current set of low level processes operate on the numerical pixel arrays, to segment the image into region and to convert the image into directional image, and to calculate feature for these regions. The current set of intermedate level processes operate on the results of earlier knowledge source to build more complex representations of the data. We have grouped into thee categories : feature based classification, geometric token relation, perceptual organization and grouping.