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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of information and communication convergence 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 2004
Volume 2, Issue 2 - Jun 2004
Volume 2, Issue 3 - Mar 2004
Volume 2, Issue 1 - Mar 2004
Selecting the target year
Performance Analysis of OFDM System Considering Carrier Frequency Offset in Wireless LAN Channel Environment
Kim, Ji-Woong ; Kang, Heau-Jo ; Lee, Kwon-Hyun ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 1~4
In this paper, We analyzes how a synchronization error affects receiving system when using OFDM(Orthogonal Frequency Division Multiplexing) transmission method in wireless LAN channel environment in which we can efficiently transmit wide-band information data. As a performance improvement method, performance distortion can be improved by applying convolution coding. As a result, in OFDM system, we could see that the higher a frequency offset is, the worse performance will be, and we could see that there was performance improvement by applying convolution coding in OFDM system in order to reach (BER=
). However, when we use 64QAM (64Quadrature Amplitude Modulation), there was a huge influence between carriers by frequency offset at 0.05, 0.1.
Performance Improvement of Multiuser DS-CDMA with Carrier Interferometry Codes in Frequency Selective Fading Channels
Chung, Yeon-Ho ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 5~8
DS-COMA is now a matured multiple access technology that utilizes spreading codes for user separation. In this paper, we attempt to improve the performance of a multiuser DS-COMA system with a unique chip shaping code called Carrier Interferometry (CI) code. The CI codes exhibit an excellent correlation property that can be used in many applications. In DS-COMA with CI codes (CI/DS-COMA), the symbols are spread by a spreading code and then the chip signals are shaped using a CI code. Due to the correlation property of the CI code, a diversity gain from the shaped chip signals is achieved and the performance of DS-COMA is significantly improved. Comparison study demonstrates that the DS-COMA with CI outperforms the conventional DS-COMA system in multiuser environments.
Radio Link Protocol Layer For CDMA 2000 Wireless Systems
A. S. Pandya ; Kim, Pyeoung-Kee ; Daniel Esso ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 9~14
In this paper the modeling of the RLP layer in CDMA2000 is presented, which uses the NAK based ARQ scheme for Random Error Channels. The RLP performs a partial link recovery through limited number of RLP frame transmission in case of frame error. In case when the RLP fails due to excessive frame error, the control is passed on to the higher (TCP) layer. The TCP layer provides the complete end-to-end recovery. Thus the reliable performance at the TCP/RLP is essential to maintain the required Quality of Service in the DS-CDMA wireless links. The modeling is done for the performance analysis of the system in terms of the throughput and the mean extra delays, which are calculated analytically and are compared with the results generated by the simulations. This paper studies the effect of the random errors over different types of RLP frame formats and also the performance of the NAK based ARQ mechanism used under these conditions. The simulation provides with the over all characteristics of the throughput and the mean extra delay in terms of realistic environment parameters like Eb/No and probability of packet error (PE), based on the channel conditions.
Performance Analysis of ABR Congestion Control Algorithm using Self-Similar Traffic
Kim, Dong-Il ; Jin, Sung-Ho ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 15~21
One of the most important issues in designing a network and realizing a service is dealing with traffic characteristics. Recent experimental research on LAN, WAN, and VBR traffic properties has highlighted that real traffic specificities can not be displayed because the current models based on the Poisson assumption under estimate the long range dependency of network traffic and self-similar peculiarities. Therefore, a new approach using self-similarity characteristics as a real traffic model was recently developed. In This paper we discusses the definition of self-similarity traffic. Moreover, real traffic was collected and we generated self-similar data traffic like real traffic to background load. On the existing ABR congestion control algorithm transmission throughput with the representative ERICA, EPRCA and NIST switch algorithm show the efficient reaction about the burst traffic.
Thick-film ammonia gas sensor with high sensitivity and excellent selectivity
Lee, Kyuchung ; Ryu, Kwang-Ryul ; Hur, Chang-Wu ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 22~25
A highly sensitive ammonia gas sensor using thick-film technology has been fabricated and examined. The sensing material of the gas sensor is FeOx-
oxide semiconductor. The sensor exhibits resistance increase upon exposure to low concentration of ammonia gas. The resistance of the sensor is decreased, on the other hand, for exposure to reducing gases such as ethyl alcohol, methane, propane and carbon monoxide. A novel method for detecting ammonia gas quite selectively utilizing a sensor array consisting of an ammonia gas sensor and a compensation element has been proposed and developed. The compensation element is a Pt-doped
gas sensor which shows opposite direction of resistance change in comparison with the ammonia gas sensor upon exposure to ammonia gas. Excellent selectivity has been achieved using the sensor array having two sensing elements.
Ontology Versions Management on the Semantic Web
Yun, Hong-Won ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 26~31
In the last few years, The Semantic Web has increased the interest in ontologies. Ontology is an essential component of the semantic web. Ontologies continue to change and evolve. We consider the management of versions in ontology. We study a set of changes based on domain changes, changes in conceptualization, metadata changes, and temporal dimension. In many cases, we want to be able to search in historical versions, query changes in versions, retrieve versions on the temporal dimension. In order to support an ontology query language that supports temporal operations, we consider temporal dimension includes transaction time and valid time. Ontology versioning brings about massive amount of versions to be stored and maintained. We present the storage policies that are storing all the versions, all the sequence of changed element, all the change sets, the aggregation of change sets periodically, and the aggregation of change sets using a criterion. We conduct a set of experiments to compare the performance of each storage policies. We present the experimental results for evaluating the performance of different storage policies from scheme 1 to scheme 5.
Color Preference and Personality Modeling using Fuzzy Logic
Kim, Kwang-Baek ; Chae, Gyoo-Yong ; Abhijit S. Pandya ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 32~35
Human ability to perceive colors is a very subjective matter. The task of measuring and analyzing appropriate colors from colored images, which matches human sensitivity for perceiving colors, has been a challenge to the research community. In this paper we propose a novel approach, which involves the use of fuzzy logic and reasoning to analyze the RGB color intensities extracted from sensory inputs to understand human sensitivity for various colors. Based on this approach, an intelligent system has been built to predict the subject's personality. The results of experiments conducted with this system are discussed in the paper.
Enhanced Fuzzy Single Layer Perceptron
Chae, Gyoo-Yong ; Eom, Sang-Hee ; Kim, Kwang-Baek ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 36~39
In this paper, a method of improving the learning speed and convergence rate is proposed to exploit the advantages of artificial neural networks and neuro-fuzzy systems. This method is applied to the XOR problem, n bit parity problem, which is used as the benchmark in the field of pattern recognition. The method is also applied to the recognition of digital image for practical image application. As a result of experiment, it does not always guarantee convergence. However, the network showed considerable improvement in learning time and has a high convergence rate. The proposed network can be extended to any number of layers. When we consider only the case of the single layer, the networks had the capability of high speed during the learning process and rapid processing on huge images.
A TINA-Based Component Modeling for Static Service Composition
Shin, Young-Seok ; Lim, Sun-Hwan ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 40~45
This paper describes a modeling of service composition manager based on TINA (Telecommunication Information Networking Architecture). The Service composition function is mainly motivated by the desire to easily generate new service using existing services from retailers or
-party service providers. The TINA-C specification for the service composition does not include the detailed composition procedure and its object models. In this paper, we propose a model of components for the service composition, which adapts a static composition feature in a single provider domain. To validate the proposed modeling, we implemented prototype service composition function, which combines two multimedia services; a VOD service and a VCS service. As a result, we obtain the specification of the detailed composition architecture between a retailer domain and a
-party service provider domain.
A Robust PID Control Method with Neural Network
Kang, Seong-Ho ; Lee, Yong-Gu ; Eom, Ki-Hwan ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 46~51
The problem of reducing the effect of an unknown disturbance on a dynamical system is one of the most fundamental issues in control design. We propose a robust PID (Proportional Integral Derivative) control method with neural network for improving the performance due to the rejection of an unknown disturbance. The proposed system consists of a model of the plant, a conventional PID controller and a multi-layer neural network, and is composed of two loop; the first loop enables the system to achieve stability of system, the second loop rejects an unknown disturbance. Simulation and experiment results show that the proposed method improves considerably on the performance of the conventional PID control method and the typical IMC method using neural network.
Active Object Tracking using Image Mosaic Background
Jung, Young-Kee ; Woo, Dong-Min ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 52~57
In this paper, we propose a panorama-based object tracking scheme for wide-view surveillance systems that can detect and track moving objects with a pan-tilt camera. A dynamic mosaic of the background is progressively integrated in a single image using the camera motion information. For the camera motion estimation, we calculate affine motion parameters for each frame sequentially with respect to its previous frame. The camera motion is robustly estimated on the background by discriminating between background and foreground regions. The modified block-based motion estimation is used to separate the background region. Each moving object is segmented by image subtraction from the mosaic background. The proposed tracking system has demonstrated good performance for several test video sequences.
Sea level observations in the Korean seas by remote sensing
Yoon, Hong-Joo ;
Journal of information and communication convergence engineering, volume 2, issue 1, 2004, Pages 58~60
Sea level variations and sea surface circulations in the Korean seas were observed by Topex/Poseidon altimeter data from 1993 through 1997. In sea level variations, the West and South Sea showed relatively high variations with comparison to the East Sea. Then, the northern and southern area in the West Sea showed the range of 20∼30cm and 18∼24cm, and the northern west of Jeju island and the southern west of Tsushima island in the South Sea showed the range of 15∼20cm and 10∼15cm, respectively. High variations in the West Sea were results to the inflow in sea surface of Yellow Sea Warm Current (YSWC) and bottom topography. Sea level variations in the South Sea were due to two branch currents (Jeju Warm Current and East Korea Warm Current) originated from Kuroshio Current (KC). In sea surface circulations, there existed remarkably three eddies circulations in the East Sea that are mainly connected with North Korea Cold Current (NKCC), East Korea Warm Current (EKWC) and Tushima Warm Current (TWC). Their eddies are caused basically to the influence of currents in sea surface circulations; Cyclone (0.03 cm/see) in the Wonsan bay off shore with NKCC, and anticyclone (0.06 cm/see) in the southwestern area of Ulleung island with EKWC, and cyclone (0.01 cm/see) in the northeastern area of Tushima island with TWC, respectively.