共查询到19条相似文献，搜索用时 812 毫秒
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近年来,随着网络技术的迅速发展,人类对互联网依赖程度的日益增强,网络流量和带宽迅速增长,在网络流量监控的各种应用（如防火墙、入侵检测系统等）中对海量数据进行捕获和分析至关重要。主要对数据捕获机制的现状进行分析,提出数据捕获机制及其改进思路。 相似文献
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现在互联网时代的大门已经彻底打开,而互联网中传输的数据无时无刻都面临着被蓄意的更改和恶意破坏的威胁,因此在互联网络途径中,互联网安全系统能保护互联网系统中计算机用户的硬件软件设施.在通过互联网络数据捕获技术实现原始数据的收集中,传输给互联网络安全系统进行分析和存储.同时也将这些互联网网络数据信息反馈给用户的计算机系统来以此增强其网络安全技术. 相似文献
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竞技体操现场技术姿态特征数据视觉感知系统可以实时准确地捕获和分析体操动作关键技术动作,对分析和指导运动员动作特征,提高训练和裁判评价水平提供数据和技术支撑。传统的竞技体操现场技术姿态特征数据视觉采集系统采用的是基于宽频带大功率数据感知的系统采集技术,对竞技体操这种技术特征要求复杂的运动项目适用性不好。提出一种基于可变增益控制放大的竞技体操现场技术姿态特征数据视觉感知系统设计技术,采用传感器自动采集竞技体操运动员人体的位置、角速度和旋转角度等信息,给出基于可变增益控制放大的竞技体操技术姿态特征提取的模型,实现系统硬件电路设计。系统实验结果表明,提取体操运动员在不同比赛时间节点上的姿态特征数据,具有较好的数据采集性能,能实时实现数据转换和调度,竞技体操现场技术姿态特征数据视觉重构效果较好,能准确和细节展示体操运动的技术性动作,性能稳定。 相似文献
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跳频同步是跳频通信系统正常工作的重要前提,直接影响其工作性能,快速跳频通信系统实现同步更为困难,针对这个技术困难,提出了FH系统的一种基于双图案的同步捕获方法,运用理论分析并仿真验证了该同步捕获方法在各种衰落信道(其中包括Rayleigh衰落信道、Rician衰落信道、Nakagami-m衰落信道)下的捕获性能.结果表明:不同衰落信道对FFH/BFSK系统的同步捕获性能不同,在相同的同步捕获门限下,处于深度衰落的Nakagami-m衰落信道对捕获性能的影响最为显著,而就同步捕获性能对门限的敏感度而言,Rayleigh衰落信道下的影响最大. 相似文献
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随着民航通信导航设备技术的发展,双频系统中引入了捕获效应的理论,在此就捕获效应的应用做一下分析讨论. 相似文献
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主要论述了结合数据库触发器技术,通过Java语言、Hibernate框架和JMS消息中间件实现异构数据库的同步.从数据同步的捕获、构造、传递、解析和更新等五个模块,阐述了异构数据库同步的基本工作原理,并给出了系统实现. 相似文献
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近年来,随着网络技术的迅猛发展和因特网的广泛普及,信息与网络的安全形势日趋严峻和复杂化,各种计算机安全事件也不断发生。网络安全问题变得日益突出,NIDS用来监视网络数据流动情况,当入侵发生时能够提供报警。详细的分析了一个基于Linux的用于用户层包捕获的系统独立的API接口Libpcap库,并给出了利用Libpcap设计基于包捕获的应用程序的应用框架。最后对该框架进行了具体实现。 相似文献
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The paper is concerned with the modeling and stabilization problem of networked control systems under simultaneous consideration of bounded packet dropouts and occasionally missing control inputs. In particular, the focus of the paper is to capture the case where the packet dropouts and control inputs missing are subject to multiple sampling periods, and not periodic as in existing results. By input-delay approach and then fully considering the probability distribution characteristic of packet dropouts in the modeling, the original linear system is firstly transformed to a switched stochastic time-delay system. Meanwhile, the probability distribution values of stochastic delay taking values in m(m ≥ 2) given intervals can be explicitly obtained, which is of vital importance to analyse the stabilization problem of considered system. Secondly, by means of the average dwell time technique, some sufficient conditions in terms of linear matrix inequalities for the existence of desired stabilizing controller are derived. Finally, an illustrative example is given to illustrate the effectiveness of the proposed stabilizing controller and some less conservative results are obtained. 相似文献
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《Journal of The Franklin Institute》2022,359(16):8621-8638
Networked systems using redundant channels to transmit data can effectively reduce the probability of data loss and improve system reliability and control margin. However, the structural complexity and economic cost of the system are also increased. To balance the redundancy and feasibility, the ratio of attraction domain to packet loss rate is defined as a balanced feasibility index. In this paper, single-channel packet loss is considered as Bernoulli distribution and a bounded packet loss network system control model is constructed as the arbitrary bounded packet loss control problem for redundant channel transmission network system. Therefore, the robust conditions of the closed-loop system and the constraints of the input and state are established under the framework of robust predictive control to construct the linear matrix inequality (LMI) optimization problem. Finally, to verify the effectiveness of the design method proposed in this paper, the discrete time-varying linear system and the main steam control system with redundant channels are used as study cases. 相似文献
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This paper is devoted to the fault detection of linear systems over networks with bounded packet loss. The inputs and the measurements of the monitored system are transmitted to a fault detection node over an unreliable network with bounded packet loss. The packet loss process is assumed to be arbitrary or Markovian in this paper. Due to the bounded packet loss process, the monitored system is modeled as a switched system by re-sampling it at each time instant when the measurements arrive at the fault detection node. A fault detection filter for this switched system is designed in this paper to satisfy some performance constraints. The filter updates only at the time instant when new measurements arrive at the fault detection node and the input data packets' lost are considered as external disturbances. Finally, the numerical example and simulations have demonstrated the usefulness of the proposed method. 相似文献
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This paper investigates the control problem for nonlinear networked control systems with global Lipschitz nonlinearities subject to output quantization and data packet dropout. The system states are unavailable and the outputs are quantized in a logarithmic form before transmitted through network. In the communication channel, two types of packet losses are considered simultaneously: (i) packet losses from sensor to controller and (ii) packet losses from controller to actuator, which are modeled as two independent Bernoulli distributed white sequences, respectively. Based on the proposed model, an observer-based controller is designed to exponentially stabilize the networked system in the sense of mean square, and sufficient conditions for the existence of the controller are established. Finally, a numerical example is presented to illustrate the effectiveness and applicability of the proposed technique. 相似文献
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提出一种基于小波包与自适应预测器的音频隐写分析方法,主要用于检测加性噪声模型.利用加性噪声对音频高频部分比低频部分影响显著的特点,对音频信号进行小波包分解;然后利用最小均方(LMS)自适应预测器对高频小波包系数进行预测,选取预测误差的统计量作为统计特征;最后采用支持向量机分类.实验证明,对于常用的加性噪声隐写方法,即使在嵌入强度或嵌入率较低的情况下,也能达到较高的分类准确率. 相似文献
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《Journal of The Franklin Institute》2019,356(17):10593-10607
This paper investigates the problem of a multi-rate networked system estimation with considering random and malicious packet losses. Three different rates are used: system sampling rate, measurement updating rate and estimation updating rate. Thus, the network energy can be saved. Since the plant and filtering are connected via network channel, the data packet losses unavoidably happen. In order to study the combination of the random and malicious packet losses, the probabilistic characterization for the link failures is applied, which leads to a stochastic estimation error system. The almost surely exponentially stability criteria is applied to guarantee this stochastic system stable. Finally, a cloud-aided vehicle suspension system is applied to verify the theoretical finding. 相似文献
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NDIS中间层驱动功能强大,是个人防火墙技术的发展趋势。介绍了利用NDIS中间层驱动截获到主机的数据包并进行分析、过滤掉有威胁的数据包的工作流程及程序。 相似文献
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基于网络的入侵检测系统数据包采样策略研究 总被引：2，自引：0，他引：2
入侵检测是信息安全研究的重要组成部分，基于网络的入侵检测系统通过详细分析计算机网络中传输的网络数据包进行入侵检测。由于检测速率与数据包采集速率不匹配，以及检测所需成本的限制，在收集用于检测的网络数据包时，必须选择有效的采样策略。本文引入博弈模型框架上的原始入侵数据包采样策略，在此基础上再进行分析和扩展。本文针对单一采样策略的缺陷与不足，引入风险管理的思想来分析在决策者不同效用偏好情况下的采样策略选择问题，并且通过具体的实例，说明了基于风险差异的采样策略选择的有效性。 相似文献