• 제목/요약/키워드: input-output matrix

검색결과 442건 처리시간 0.027초

Combining Adaptive Filtering and IF Flows to Detect DDoS Attacks within a Router

  • Yan, Ruo-Yu;Zheng, Qing-Hua;Li, Hai-Fei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제4권3호
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    • pp.428-451
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    • 2010
  • Traffic matrix-based anomaly detection and DDoS attacks detection in networks are research focus in the network security and traffic measurement community. In this paper, firstly, a new type of unidirectional flow called IF flow is proposed. Merits and features of IF flows are analyzed in detail and then two efficient methods are introduced in our DDoS attacks detection and evaluation scheme. The first method uses residual variance ratio to detect DDoS attacks after Recursive Least Square (RLS) filter is applied to predict IF flows. The second method uses generalized likelihood ratio (GLR) statistical test to detect DDoS attacks after a Kalman filter is applied to estimate IF flows. Based on the two complementary methods, an evaluation formula is proposed to assess the seriousness of current DDoS attacks on router ports. Furthermore, the sensitivity of three types of traffic (IF flow, input link and output link) to DDoS attacks is analyzed and compared. Experiments show that IF flow has more power to expose anomaly than the other two types of traffic. Finally, two proposed methods are compared in terms of detection rate, processing speed, etc., and also compared in detail with Principal Component Analysis (PCA) and Cumulative Sum (CUSUM) methods. The results demonstrate that adaptive filter methods have higher detection rate, lower false alarm rate and smaller detection lag time.

Efficient Link Adaptation Scheme using Precoding for LTE-Advanced Uplink MIMO (LTE-Advanced에서 프리코딩에 의한 효율적인 상향링크 적응 방식)

  • Park, Ok-Sun;Ahn, Jae-Min
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제36권2B호
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    • pp.159-167
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    • 2011
  • LTE-Advanced system requires uplink multi-antenna transmission in order to achieve the peak spectral efficiency of 15bps/Hz. In this paper, the uplink MIMO system model for the LTE-Advanced is proposed and an efficient link adaptation shceme using precoding is considered providing error rate reduction and system capacity enhancement. In particular, the proposed scheme determines a transmission rank by selecting the optimal wideband precoding matrix, which is based on the derived signal-to-interference and noise ratio (SINR) for the minimum mean squared error (MMSE) receivers of $2{\times}4$ multiple input multiple output (MIMO). The proposed scheme is verified by simulation with a practical MIMO channel model. The simulation results of average block-error-rate(BLER) reflect that the gain due to the proposed rank adapted transmission over full-rank transmission is evident particularly in the case of lower modulation and coding scheme (MCS) and high mobility, which means the severe channel fading environment.

Experimental Data based-Parameter Estimation and Control for Container Crane (실험적 데이터 기반의 컨테이너 크레인 파라미터 추정 및 제어)

  • Lee, Yun-Hyung;Jin, Gang-Gyoo;So, Myung-Ok
    • Journal of Navigation and Port Research
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    • 제32권5호
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    • pp.379-385
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    • 2008
  • In this paper, we presents a scheme for the parameter estimation and optimal control scheme for apparatus of container crane system. For parameter estimation, first, we construct the open loop of the container crane system and estimate its parameters based on input-output data, a real-coded genetic algorithm(RCGA) and the model adjustment technique. The RCGA plays an important role in parameter estimation as an adaptive mechanism. For controller design, state feedback gain matrix is searched by another RCGA and the estimated model. The performance of the proposed methods are demonstrated through a set of simulation and experiments of the experimental apparatus.

Parameter Estimation and Control for Apparatus of Container Crane;An Experimental Approach (모형 컨테이너 크레인의 파라미터 추정 및 제어;실험적 접근)

  • Lee, Yun-Hyung;Jin, Gang-Gyoo;So, Myung-Ok
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 한국항해항만학회 2007년도 추계학술대회 및 제23회 정기총회
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    • pp.304-306
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    • 2007
  • In this paper, we presents a scheme for the parameter estimation and optimal control scheme for apparatus of container crane system. For parameter estimation, first, we construct the open loop of the container crane system and estimate its parameters based on input-output data, a real-coded genetic algorithm(RCGA) and the model adjustment technique. The RCGA plays an important role in parameter estimation as an adaptive mechanism. For controller design, state feedback gain matrix is searched by another RCGA and the estimated model. The performance of the proposed methods are demonstrated through a set of simulation and experiments of the experimental apparatus.

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Dual-mode Transmission Strategy for Blind Interference Alignment Scheme in MISO Broadcast Channels (MISO 브로드캐스트 채널에서의 블라인드 간섭 정렬 기법 기반 이중 전송 기법 설계)

  • Yang, Minho;Jang, Jinyoung;Kim, Dong Ku
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제38A권12호
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    • pp.1102-1109
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    • 2013
  • Blind interference alignment (BIA) scheme has demonstrated a way of interference alignment (IA) without channel state information at transmitter (CSIT). While it shows superior performance in high signal-to-noise ratio (SNR) regime stemming from the maximal degrees of freedom (DoF) gain, BIA scheme achieves inferior sum-rate performance in low SNR regime. This paper proposes a dual-mode transmission strategy which switches between single user (SU) SISO with receive mode selection and the BIA scheme depending upon the range of SNR. First, we derive a closed-form achievable rate for each transmission-mode. Secondly, we propose a low-complex transmission-mode selection algorithm.

Vertical Sectorization Techniques in MISO Downlink Active Antenna Systems (MISO 하향 능동 안테나 시스템에서의 수직 섹터분할 기법)

  • Ahn, Minki;Eom, Subin;Lee, Inkyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제40권6호
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    • pp.997-1004
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    • 2015
  • In this paper, we study vertical sectorization techniques in multiple-input single-output (MISO) downlink active antenna systems (AAS). In the AAS, antenna beam patterns can be adjusted in each sector and multiple vertical beams can form the vertical sectorization. Since an exhaustive search based vertical sectorization algorithm requires high computational complexity to find the optimal tilt angles, we propose two vertical sectorization algorithms to reduce the complexity. First, we provide an asymptotic sum rate based algorithm which utilizes a large system approximation of the average sum rate based on the random matrix theory. Next, by using the result in the single sector transmission, the single sector based algorithm is proposed. In the simulation results, we confirm that the proposed algorithms are close to the performance of the exhaustive search algorithm with much reduced complexity.

Theoretical Analysis of MIMO Antenna Selection & Switching System to Spatial Channel Correlation using Channel Statistics (공간적 채널 상관도에 따른 통계적인 채널 특성을 이용한 다중 안테나 선택 및 스위칭 시스템의 성능 분석)

  • Lee Hakju;Park Seungil;Lee Chungyong;Park Hyuncheol;Hong Daesik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • 제42권4호
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    • pp.15-20
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    • 2005
  • Multi-Input, Multi-Output system suffers for the spatial channel correlation due to lack of spatial diversity. To overcome this defect, the antenna selection and switching system is proposed which selects the adequate antenna subset with highest channel diversity gain and switches the trasmission techniques according to channel environments. However. its performance analysis is insufficient due to the difficulty of modeling the spatial channel correlation. In this paper, the theoretical upper bound of symbol error probability is derived by using the statistical properties of Frobenius norm and minimum eigen-value of channel matrix. By computer simulation, it is shown that the derived theoretical upper bound is similar to the simulation results.

Modeling of Magentic Levitation Logistics Transport System Using Extreme Learning Machine (Extreme Learning Machine을 이용한 자기부상 물류이송시스템 모델링)

  • Lee, Bo-Hoon;Cho, Jae-Hoon;Kim, Yong-Tae
    • Journal of the Institute of Electronics and Information Engineers
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    • 제50권1호
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    • pp.269-275
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    • 2013
  • In this paper, a new modeling method of a magnetic levitation(Maglev) system using extreme learning machine(ELM) is proposed. The linearized methods using Taylor Series expansion has been used for modeling of a Maglev system. However, the numerical method has some drawbacks when dealing with the components with high nonlinearity of a Maglev system. To overcome this problem, we propose a new modeling method of the Maglev system with electro magnetic suspension, which is based on ELM with fast learning time than conventional neural networks. In the proposed method, the initial input weights and hidden biases of the method are usually randomly chosen, and the output weights are analytically determined by using Moore-Penrose generalized inverse. matrix Experimental results show that the proposed method can achieve better performance for modeling of Maglev system than the previous numerical method.

Subspace Method Based Preceding for Spatial Multiplexing with Limited Feedback (제한된 피드백 정보를 사용하는 공간 다중화를 위한 부 공간 방식 기반 Precoding 기법)

  • Mun Cheol;Seo Jeong-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제30권10A호
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    • pp.906-911
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    • 2005
  • In this paper, for spatial multiplexing with limited feedback, we propose subspace method based preceding in which the active bases are selected at the receiver from a finite number of basis sets Down at both receiving and transmitting ends, conveyed to the transmitter using limited feedback, and assembled into a preceding matrix at the transmitter. The selected bases are conveyed to the transmitter using feedback information on both the index of the selected basis set, which defines the most appropriate set of coordinates for describing a multiple-input multiple-output (MIMO) channel, and the principal bases maximizing the capacity in the selected basis set. We show that the proposed subspace method based preceding provides a capacity similar to that of the closed-loop MIMO even with limited feedback.

Design of Absorptive Type SPST MMIC Switch for MSM of Satellite Communication (위성통신용 MSM을 위한 흡수형 SPST MMIC 스위치의 설계 및 제작)

  • Yom In-Bok;Ryu Keun-Kwan;Shin Dong-Hwan;Lee Moon-Que;Oh Il-Duck;Oh Seung-Hyeub
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • 제16권10호
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    • pp.989-994
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    • 2005
  • A MMIC(Monolithic Microwave Integrated Circuit) switch chip using InGaAs/GaAs p-HEMT process has been designed for MSM(Microwave Switch Matrix) of satellite communication system. An absorptive type MMIC switch is adopted for good reflection coefficients performances of input and output ports at both on and off states. And, a quarter wavelength impedance transformer is realized with lumped elements of MIM capacitor and spiral inductor for 3 GHz band to reduce the chip size. This MMIC switch covers the frequency range of $3.2\~3.6\;GHz$. According to the on-wafer measurement, the fabricated MMIC switch with miniature size of $1.6\;mm{\times}1.3\;mm$ demonstrates insertion loss below 2 dB and isolation above 56.8 dB, and the performance coincides with simulation results.