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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 23, Issue 9A - Sep 1998
Volume 23, Issue 8 - Aug 1998
Volume 23, Issue 7 - Jul 1998
Volume 23, Issue 6 - Jun 1998
Volume 23, Issue 5 - May 1998
Volume 23, Issue 4 - Apr 1998
Volume 23, Issue 9 - 00 1998
Selecting the target year
On Designing 4-way Superscalar Digital Signal Processor Core
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1409~1418
The recent audio CODEC(Coding/Decoding) algorithms are complex of several coding techniques, and can be divided into DSP tasks, controller tasks and mixed tasks. The traditional DSP processor has been designed for fast processing of DSP tasks only, but not for controller and mixed tasks. This paper presents a new architecture that achieves high throughput on both controller and mixed tasks of such algorithms while maintaining high performance for DSP tasks. The proposed processor, YSP-3, operates four algorithms while maintaining high performance for DSP tasks. The proposed processor, YSP-3, operates functional units (Multiplier, two ALUs, Load/Store Unit) in parallel via 4-issue super-scalar instruction structure. The performance evaluation of YSP-3 has been done through the implementation of the several DSP algorithms and the part of the AC-3 decoding algorithms.
Evaluation of the exact optimum tilt angles in elevation scanned phase array radars
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1419~1424
In phased array antennas that scan elevation, the number of radiator rows is one of the important factors to minimizing both cost and weitht. Therefore, the antenna tilt angles having relation with element spacing are among the improtant design parameters. The exact optimum tilt angles for several types of uniformly and nonuniformly excited arrays are obtained theoretically. Four types of uniform linear arrays and Chebyshev array factors as a nonuniformly excited arrav are considered.
Propagation characteristic analysis and measurement of gaussian pulse signals on the microstrip line
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1425~1432
The propagation properties of Gaussian pulse signals on the microstrip line are investigated by the Kirschning & Jansen's approximated equation to meet the frequency range of a pulse, accuracy, and geometrical requiremtns of the microstrip line. The dispersion of pulse signals is analyzed regarding to the relative permittivity .epsilon.
, substrate height h and strip width w of the microstrip line. To verify theoretical results, several samples of 50.OMEGA. microstrip lines are fabricated. And the characteristics of pulse propagation along these lines are simple measured using VNA(Vector Network Analyzer) with time-domain analysis function. A fairly good agreement has been found between the measured pulse waveforms and computer simulations.
A design of dual AC-3 and MPEG-2 audio decoder
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1433~1442
The thesis presents a dual audio decoder which can decode both AC-3 and MPEG-2 bitstream. The MPEG-2 synthesis processi s optimized via FFT to establish the common data path with AC-'3s. A dual audio decoder consists of a DSP core which performs the control-intensive part of each algorithm and a common synthesis filter which perfomrs the computation-intensive part. All the components of the dual audio decoder have been described in VHDL and simulated with a SYNOPSYS tool. The software modeling of the DSP core was used for functional validation. After being synthesized using 0.6 .mu.m-3ML technology standard cell, the dual audio decoder was simulated at gate-level with a COMPASS tool for hardware validation.
Speech syntheis engine for TTS
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1443~1453
This paper presents the speech synthesis engine that converts the character strings kept in a computer memory into the synthesized speech sounds with enhancing the intelligibility and the naturalness by adapting the waveform processing method. The speech engine using demisyllable speech segments receives command streams for pitch modification, duration and energy control. The command based engine isolates the high level processing of text normalization, letter-to-sound and the lexical analysis and the low level processing of signal filtering and pitch processing. The TTS(Text-to-Speech) system implemented by using the speech synthesis engine has three independent object modules of the Text-Normalizer, the Commander and the said Speech Synthesis Engine those of which are easily replaced by other compatible modules. The architecture separating the high level and the low level processing has the advantage of the expandibility and the portability because of the mix-and-match nature.
A Nonparametric Detector Based on Median-Shift Sign: Asymptotic and Finite Sample-Size Performance
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1454~1460
In this ppaer, we propose a new detector based on the median-shift sign, and then investigate its asymptotic and finite sample-size performance. We call it the median-shift sign (MSS) detector, which is an extension of the classical sign detector. First, we consider the asymptotic opti$
median shift values and their characteristics. Next, we consider the asymptotic relative efficiency of the MSS detectors. we then consider the problem of detecting known signals in noise of known probability density function, and the problem of detecting known signals when only partial information is available on the noise.
An activity based bit allocation method for still picture coding
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1461~1470
Bit allocation or quantizer assigning problem is a basic and essential issue in lossy picture coding. It could be represented as minimizing overall distortion with the given constraint that total bits should not exceed allowed bit-budget. Optimal solution can be found by Lagrangian method. However this method needs much computational time and memory. This paper presents an approximation method that uses the activity measure. The comparison between the existing activity measuring techniques are made, and mapping function from activity value to the quantizer is proposed. Under MPEG-1 Intra coding situation, simulations show almost identical results compared to the optimal ones obtained by Lagrangian method with reduced computational time.
Digital image stabilization based on bit-plane matching
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1471~1481
In this paper, we propose a new digital image stabilization scheme based on the bit-plane matching. In the proposed algorithm, the conventional motion estimation algorithms are applied to the binary images extracted from the bit-plane images. It is shown that the computational complexity of the proposed algorithm can be significantly reduced by replacing the arithmetic calculations with the binary Boolean functions, while the accuracy of motion estimation is maintained. Furthermore, an adaptive algorithm for selecting a bit-plane in consideration of changes in external illumination can provide the robustness of the proposed algorithm. We compared the proposed algorithm with existing algorithms using root mean square error (RMSE) on the basis of the brute-force method, and proved experimentally that the proposed method detects the camera motion more accurately than existing algorithms. In addition, the proposed algorithm performs digital image stabilization with less computation.
A study on the enhancement and compression algorithm for the fingerprint
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1482~1489
This paper aims to extract characteristics of the spectrum of fingerprint image and to apply them to image enhancement techniques in spatial frequency domain. Based on 1
64 window as a processing unit and the different record lengths(32, 16, 8), the estimate of power spectrum density for each length was made. Each acquired spectrum characteristics was applied to the re-synthesis process of the fingerprint image, an improved gray scale image was obtained. In order to select an optimal predictor and the Huffman table for the fingerprint iamge, the lossless JPEG algorithm was used. Experiments were performed for extracting distribution characteristics for the each of 7 predictors from the fingerprint image and modeling processes, and the result was applied to the data compression algorithm and the selection of the optimal predictor.
The analysis and modeling of the performance improvement method of multistage interconnection networks
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1490~1495
Call packing has been recognized as a routing scheme that significantly reduces the blocking probability of connection requests in a circuit-switched Clos multistage interconnection network. In this paper, for the first time, a general analytical model for the point-to-point blocking probability of the call-packing scheme applied to Clos networks is developed. By introducing a new parameter called the degree of call packing, the model can correctly estimate the blocking probability of both call-packing and random routing schemes. The model is verified by computer simulation for various size networks and traffic conditions.
Implementation of an Audio Broadcasting Service over the Internet
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1496~1502
In this paper, a real-time audio broadcasting service system which is robust to loaded traffic on the Internet is developed. For implementing reliable real-time data transfer, the transfer characteristics of TCP/IP and UDP/IP was compared and analyzed. For lost packet recovery, redundant audio data algorithm was used and interleaving technique was applied for scattering consecutive packet loss. Test results showed, when using TCP/IP, pause occurred during playback, and when using UDP/IP, a stable receive rate was noticeable but the quality of the sound was lower than that of uisng TCP/IP. The recovery rate using redundant audio data and interleaving technique is shown in Fig. 9 and the delay is shown in Fig 4.
Performance analysis of the B-NT system using simulstor
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1503~1513
This paper is related to a performance analysis of B-NT system, which is essential compositional equipment of B-ISDN access network. A simulator enabling performance analysis according to the change of network configuration topology and the change of user traffic is developed in this study. The developed B-NT, system simulator consists of graphic user interface module, simulation program automatic generator module, and B-NT system model library module. As examples of the results of performance analysis using the simulator, end-to-end user cell transmission delay time, queueing delay time in each system, and cell loss rate in the head node switch are presented. The simulator developed in this paper can be utilized in determining the network topology of B-NT system.
Performance Analysis of Multiplexed VBR MPEG Video Traffic With Arbitrary Starting Times in ATM Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1514~1525
Two main characteristics of VBR MPEG video traffic are different statistics according to different picture types and the periodic traffic pattern due to GOP structure. Especially, the I-pictures at the beginning of each GOP generate $
h more traffic than other pictures. When several VBR Mpeg video sources are superposed, the I-picture starting times of these sources may significantly affect the cell loss characteristics of ATM $
tiplexers. In this paper, we propse a performance model for ATM $
tiplexers with VBR MPEG video sources whose starting times are arbitrary given. For analysis, both single and superposed source traffic are modeled as NDPPs (non-deterministic periodic processes), and the ATM $
tiplexer is modeled as a U-state NDPPD/D/1/B queueing system. It is hown that the numerical results are very close to the si$
ation results. From the relationships between the starting tiem distributions and the corresponding $
tiplexer performances, some considerations for designing a scheduling policy in order to obtain the maxi$
tiplexing gain are presented.
Multipoint multimedia communication service in broadband ISDN part II : NOEG video bridge based on non-transcoding mechanism
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1526~1537
The split-screen function on the multipoint control unit(MCU) which is usually using processing method based on pixel domain has many problems for manipulating the video signal in real-time. Although the researches and the developements to cope ith such problems are processing, these have too complex architecture to implement and are limited to method for H.261 video signal. In this paper, we propose a new mechanism for split-screen that can actually apply to ISO/IEC MPEG video standard. The new method that is proposed in this paper do the processes in complete compression domain, thus it is suitable for the application of real-time multipoint multimedia communication service. By simple interpreting and manipulating the MPEG video element stream, the split-screen functional module can be implemented easily and the result of the procedures does not accompany image degradation at all. Finally, the complexity of implementation, the aspect for processing delay and the loss of image quality as compared to that resulting in the case of applying the previous split-screen method has been investigated. And it is confirmed that the proposed mechanism has a significant advantage as a split-screen method.,
A Study on Fault-Tolerant System Construction Algorithm in General Network
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1538~1545
System reliability has been a major concern since the beginning age of the electronic digital computers. One of the modest ways of increasing reliability is to design fault-tolerant system. This paper propose a construction mechanism of fault-tolerant system for the general graph topology. This system has several spare nodes. Up to date, fault-tolerant system design is applied only to loop and tree networks. But they are very limited cases. New algorithm of this paper tried to have a capability which can be applied to any kinds of topologies without such a many restriction. the algorithm consist of several steps : minimal diameter spaning tree extraction step, optimal node decision step, original connectivity restoration step and finally redundancy graph construction step.
A human identification scheme using visual cryptography
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1546~1553
In this paper, we investigate a human identification scheme using visual cryptography, which can decode concealed images without and crytographic computations. T.Katoh & H.Imai proposed a secret sharing scheme which can conceal two query images into one displayed image for the identification. the generalized construction of the share matrix is proposed to conceal the multiple query images by stacking user slides o the displayed image. Furthermore, an extended methodis proposed in which group of slides can conceal an independent secret image as well as the pairs of slides can.
Block loss analysis of queuing stragegy with 2-level overload control
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1554~1561
When the superposition of realtime traffic and non-realtime traffic is applied to the ATM network, the successive cell loss(block loss) is more influential on the quality of service (QoS) of two traffic streams than the single loss in case of bursty traffic. Block loss can be identified as an important performance measure because of delay-oriented policy for realtime traffic. In this paper, we consider the system with the two-level overload control reducing of the recurrence of shut-down periods and develop a recursive algorithm to obtain both block loss and cell loss probabilities of both traffic. We can see that it gives the more precise and diverse investigations on performance analysis of queuing strategy.
A System Development, Performance Assessment, and Service Implementation of ATM-based High-rate Digital Subscriber Line (HDSL)
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1562~1574
We, in this paper, have implemented T1, E1 and fractional E1 HDSL(High-bit-rate digital subscriber line) function over an ATM switching system. The maxi
loop lengths for subscriber service and cell loss rates to meet the bit error rate of 10
at transmission of 2B1Q HDSL data E1 rate over existing telephone copper wires in the presence of the significant impairments such as NEXT(Nearned crosstalk), impulse noise, power line noise and longitudinal over the CSAs environment consisting of 26 gauge and 25 gauge unloaded copper telephone lines has assessed. HDSL will intially be used to serve private-DS1, ISDN-BRA, and DLC feeders, later DS1 extension from optic fiber cable. We also present market provision for the HDSL.
Design and synthesis of reed-solomon encoder and decoder using modified euclid's algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1575~1582
Reed-Solomon(RS) code which is especially effective against burst error is studied as a forward error correction technique in this ppaer. The circuits of RS encoder and decoder for ASIC implementation are designed and presented employing modified Euclid's algorithm. The functionalities of the designed circuits are verified though C programs which simulates the circuits over the various errors and erasures. The pipelined circuits using systolic arrays are designed for ASIC realization in VHDL, and verified through the logic simulations. Finally the circuit synthesis of RS encoder and decoder can be achieved.
Quasi-ML Multiusers Detection with a Rake Receiver in Asynchronous DS/CDMA System: 2. The Time-Varying Channel Case
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1583~1591
In this paper, we consider the quasi maximum likelihood(quasi-ML) detector which uses antenna arrays in asynchronous time-varing channels. It is shown that the proposed quasi-ml detector can be regarded as a beamformer followed by a decorrelator: a method based on the eigendecomposition of the correlation matrix of the inverse-filtered signal is proposed to estimate the channel vectors. We also show that the proposed algorithm estimates the channel vector within small mismatch loss in severe propagation environment through computer simulations.
Prediction model of wave propagation inside buildings including specular and diffracted transmission and reflection
Kim, Seong-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1592~1601
The growing use of unlicensed wireless systems has spurred interest in the 2.4 Ghz ISM band. In order to facilitate the efficient design of such systems, understandings of the propserties of radio wave propagation in buildings is necessary. Many authors have reported about statistical propagation models based on the extensive measurements in buildings. However, measurement based statistical analysis will not be enough for the optimum deployment of the communication systems in the specific building. Aviding expensive measurements in the individual buildings prior to installation, or adjustments afterwards, theoretical prediction models have been developed to predict the path loss and delay spread from the building floor plane. Predictions shows good agreements with measurements except for a few environments which was surrounded by heavy scatterers.
Novel RF front-end circuit for CDMA based PCS phone
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1602~1609
In this paper, the design and implementation of the novel RF front end circuit for CDMA based PCS phone is described. This novel scheme is realized by building the power amplifier module combined with duplexer. The dielectric filters which are parts of duplexer are broken up and relocated into the module. Electromagnetic analysis for via holes and coupling between narrow transmissio lines is icluded to design a circuit. The combined moule has been minimaturized to be as small as 1.5CC. It has satisfied IS-95 requirements for linearity performances of CDMA signal at 24-dBm output power as well as played apart as a duplexer. The operating current of about 95mA has been saved owing to both rearranging dielectric filters and limiting operating point to class-B by considering real working power range of CDMA phones.
The FB mechanism for TCP traffic over UBR connections in the subnet ATM model
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1610~1618
In this paper, we present the FB(Fair Buffering) mechanism for the efficient support of TCP traffic over UBR connections in the subnet ATM model. We show that both throughput and fairness may be improved with the FB mechanism. The FB mechanism is founded on the observation that the performance of TCP over UBR connections is optimal when the buffer space is allocated in proportion to the connection's bandwidth-delay product. We compare through simulation the performance of the existing drop-tail, EB(Equal Buffering) and the proposed FB buffer management schemes, with and without RR(Roung-Robin) scheduling, and demonstrate that the proposed FB mechanism is most effective when used in conjunction with the RR scheduling scheme.
A Study on the Numbering Plane for IMT-2000
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1619~1626
In this paper, we made researches into considerations for the numbering plan for IMT-2000 that seems to be a unit system integrating cellular, satellite, PCS. The purposes of the numbering plane for IMT-2000 ARE SIMILAR TO IMT-2000 evolution form:constructing the numbering plane centering around UPT as a PRE-FPLMTS from and futhermore, adding terminal mobility to IMT-2000. For this paper, we established three numbering plans for IMT-2000 that accepts various considerations.
A Study on Pricing Policy for Consolidata Competition on the Telephone Service Market in Korea
The Journal of Korean Institute of Communications and Information Sciences, volume 23, issue 6, 1998, Pages 1627~1638
In this paper, we made reaserch into an effective pricing policy for competitive structure on telephone market in Korea by using that of foreign examples and what level of price gap between esisting service provider and new service provider is adequate by using a stochastical analysis. Simulation result shows to remove the existing service provider under current telecommunication structure in Korea, rapid increase of telephone service is needed. And to consolidata competition, the existing service provider, Korea Telecom, shall be run by private management. Futhermore, local call service and long-distance call service shall be separated.