• Title/Summary/Keyword: 미상신호

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A Study of the Design of NIDS System for the Effective Information Detection (효율적인 정보검출을 위한 NIDS 시스템 설계에 관한 연구)

  • 이선근
    • Journal of the Korea Society of Computer and Information
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    • v.8 no.3
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    • pp.156-162
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    • 2003
  • With the network environment and user's application service increasing information protection and private information protection fields are very important fields. But it is necessary detection methodology to unspecified unknown signal, information increasing and various information media. Therefore in this thesis, we design NIDS that classify others information for detection of the unknown signal as the unauthenticated signal or illegal outer access, etc. proposed NIDS design used Synopsys Ver. 1999 and VHDL. The proposed NIDS system is practical in the system performance and cost for the individually existed NIDS, and utilized a part of system resources.

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A Study of the Merged IDS Design for the Unknown Signal Detection (미상신호 검출을 위한 통합 IDS 설계에 관한 연구)

  • 이선근;김환용
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5B
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    • pp.381-387
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    • 2003
  • The importance of protection for data and information is increasing by the rapid development of information communication and network. And concern of the private-information protection is increasing for the requested user's demand. Analysis of unknown signal characteristics is importance for the safe system maintenance from hacker and cracker. Detected target of unknown signals is virus, inner invader and outer invader, etc. Because existed unknown signal detection method exist individually for the virus, inner invader and outer invader system performance is very lower and system cost is very much. Therefore, in this paper proposed merging IDS system performs detection for virus, inner intrusion and outer intrusion method. Design of the proposed system is used Synopsys Ver. 1999.10 and VHDL coding. The proposed IDS system is practical in the system performance and cost for the individually existed IDS, and proposed IDS system utilized a part of system resources.

A Subspace-based Blind Interference Cancellation for the DS/CDMA System (직접수열 코드분할 다중접속 시스템의 부공간 기반 미상 간섭 제거 기법)

  • 윤연우;김형명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.11B
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    • pp.1510-1521
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    • 2001
  • In this paper a subspace-based blind interference cancellation is proposed and its performance is analyzed. Then the blind adaptive implementation is devolped using the improved natural power method which is the signal subspace tracking algorithm. The theoretical analysis shows that when the exact covariance matrix is kown the performance of the proposed detector is the same as that of the decorrelating detector. And when the covariance matrix is estimated the asymptotic results are examined. The results of computer simulation demonstrate that the proposed detector outperforms the previous blind adaptive RLS MOE detector.

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Weighted Energy Detector for Detecting Uunknown Threat Signals in Electronic Warfare System in Weak Power Signal Environment (전자전 미약신호 환경에서 미상 위협 신호원의 검출 성능 향상을 위한 가중 에너지 검출 기법)

  • Kim, Dong-Gyu;Kim, Yo-Han;Lee, Yu-Ri;Jang, Chungsu;Kim, Hyoung-Nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.3
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    • pp.639-648
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    • 2017
  • Electronic warfare systems for extracting information of the threat signals can be employed under the circumstance where the power of the received signal is weak. To precisely and rapidly detect the threat signals, it is required to use methods exploiting whole energy of the received signals instead of conventional methods using a single received signal input. To utilize the whole energy, numerous sizes of windows need to be implemented in a detector for dealing with all possible unknown length of the received signal because it is assumed that there is no preliminary information of the uncooperative signals. However, this grid search method requires too large computational complexity to be practically implemented. In order to resolve this complexity problem, an approach that reduces the number of windows by selecting the smaller number of representative windows can be considered. However, each representative window in this approach needs to cover a certain amount of interval divided from the considering range. Consequently, the discordance between the length of the received signal and the window sizes results in degradation of the detection performance. Therefore, we propose the weighted energy detector which results in improved detection performance comparing with the conventional energy detector under circumstance where the window size is smaller than the length of the received signal. In addition, it is shown that the proposed method exhibits the same performance under other circumstances.

Blind identification of nonminimum phase FIR systems from second-order statistics and absolute mean (2차 통계값과 절대평균을 이용한 비최소 위상 FIR 시스템의 미상 식별)

  • 박양수;박강민;송익호;김형명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.2
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    • pp.357-364
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    • 1996
  • This paper presents a new blind identification method of nonminimum phase FIR systems without employing higher-order statistics. It is based on the observation that the absolute mean of a second-order white sequence can measure the higher-order whiteness of the sequence. The proposed method may be a new alternative way to the higher-order statistics approaches. Some computer simulations show that the absolute mean is exactly estimated and the proposed method can overcome the disadvantages of the higher-order statistics approaches.

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Hopping Information Generation of Unknown Frequency Hopping Signals in Wireless Channel Environments (무선채널환경에서 미상의 주파수 도약신호에 대한 도약정보 생성 기법)

  • Ahn, Junil;Lee, Chiho;Jeong, Unseob
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.3
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    • pp.215-222
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    • 2019
  • A frequency hopping(FH) signal can change its carrier frequency during transmission and has spread-spectrum characteristics in these frequency bands. Therefore, FH signals are widely used in applications that require low-probability-of-intercept(LPI) and anti-jamming (AJ) abilities in wireless communication environments. In this study, the authors propose a method for generating hopping information (HI), which includes start time, dwell time, and hopping frequency for unknown FH signals. The proposed blind HI generation method produces signal detection information based on the spectrum data and then extracts HI using operational procedures for estimating the target FH signal's status, such as appearance, maintenance, and termination. Further, simulation results demonstrate that the proposed method provides accurate HI without detection omissions for various FH signals.

Simple Blind Channel Estimation Scheme for Downlink MC-CDMA Systems (하향링크 MC-CMDMA 시스템을 위한 간단한 미상 채널 추정 방법)

  • Seo, Bang-Won
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.6A
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    • pp.480-487
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    • 2012
  • In multicarrier code-division multiple access (MC-CDMA) systems, conventional blind channel estimation schemes require the inverse matrix calculation or eigenvalue decomposition of the received signal covariance matrix. Therefore, computational complexity of the conventional schemes is too high and they cannot be employed in downlink systems. In this paper, we propose a simple blind channel estimation scheme with very low computational complexity. Simulation results show that the proposed scheme has better channel estimation and bit error rate (BER) performance than the conventional schemes.

Comparative Study of the Symbol Rate Detection of Unknown Digital Communication Signals (미상 디지털 통신 신호의 심볼율 검출 방식 비교)

  • Joo, Se-Joon;Hong, Een-Kee
    • Journal of Advanced Navigation Technology
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    • v.7 no.2
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    • pp.141-148
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    • 2003
  • This paper presents and compares several techniques that detect the symbol rate of unknown received signal. Symbol rate is detected from the power spectral density of the circuits such as the delay and multiplier circuit, the square law circuit, and analytic signal, etc. As a result of discrete Fourier transform of the output signals of these circuits, a lot of spectral lines and some peaks appear in frequency domain and the position of first peak is corresponding to the symbol rate. If a spectral line on the frequency that is not located in symbol rate is larger than the first peak, the symbol rate is erroneously detected. Thus, the ratio between the value of first peak and the highest side spectral line is used for the measure of the performance of symbol rate detector. For the MPSK modulation, the analytic signal method shows better performance than the delay and multiplier and square law circuits when the received signal power is lager than -20dB. It is also noted that the delay and multiplier circuit is not able to detect the symbol rate for the QAM modulation.

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The Identification of Digitally Modulated Signal Formats using a Self-Organized Neural Network (자율조직 신경망을 이용한 디지털 변조형식 식별)

  • 김진구;홍의석
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.10
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    • pp.1894-1899
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    • 1994
  • In this paper, a new identification method is proposed for unknown digitally modulated input signals. The proposed identification method is implemented using a self-organized neural network which is based on the characteristic features of the symbol magnitude; the number of symbol magnitude levels, amplitude probability density and adjacent symbol magnitude ratio. The proposed method was performed for 5 QAM signals. The simulation results show that the self-organized neural network can accurately recognize all kinds of patterns even at SNR 8dB. The proposed method can be applied to the intelligent communication system on ISDN and multi-point polling networks.

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An Algorithm for De-Interleaving of Wobble and Sinusoidal PRIs for Unidentified Radar Signals (미상 레이더의 Wobble 및 Sinusoidal PRI 식별 알고리즘)

  • Lee, Yongsik;Lim, Joongsoo;Lim, Jaesung
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.12
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    • pp.1100-1107
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    • 2015
  • In this paper, we propose an algorithm to identify Wobble PRI and Sinusoidal PRI among Radar pulses. We applied not only the DTOA(Difference Time Of Arrival) concept of radar pulse signals incoming to antennas but also a rising and falling cub characteristic of those PRIs. After making a program by such algorithm, we input each 40 data to Wobble PRI's and Sinusoidal PRI's identification programs and in result, those programs fully processed the data the according to expectations. In the future, those programs can be applied to the ESM, ELINT system.