网络监控系统中数据包捕获分析模块的实现

网络监控系统对所有的网络行为进行监控,诸如监控对互联网的访问及监控局域网之间的通信等。本文主要介绍了网络监控系统中的数据包捕获模块的设计与实现,和以网络监控系统在监控对互联网的访问方面的应用为例,介绍了网络监控系统中的数据包分析模块的设计与实现。     

Accounting of heterogeneity in the estimation of radiation risks

The problem is considered of taking account of heterogeneity in the individual radiosensitivity in evaluating the radiation risk of the origin of a disease in a group of persons subjected to the radiation action. Mathematical models are described for the estimation of the radiation risk of the origin of the disease with and without regard for heterogeneity. The use of the described method is demonstrated with an example of the estimation of the risk of the origin of radiation-induced diseases from the class of “solid cancers” among the persons taking part in the liquidation of consequences of the accident at the Chernobyl’ Atomic Power Station (CAPS) in the years 1986–1991. It is shown that the heterogeneity disregard leads to understated estimates of the radiation risk of the origin of radiation-induced solid cancers. The effect is investigated of the length of the latent period in the origin of radiation-induced “solid cancers” in taking account of heterogeneity.     

Estimation of the information safety level of modern infocommunication networks on the basis of the logic-probability approach

The condition of accessibility of the admissible level of protectiveness of an object of the infocommunication network from attack is stated. For the full set stipulated by irreversible, invariant, cause-effect links of the information protection functions, the logic-probability models of the estimation of protectiveness of the object of infocommunication networks are obtained. On the basis of the introduced notion of gradations of the information protection functions and their characteristics with the use of the Bayes formalism, for statistic data the statements are set up for the organization of the identification of the obtained probabilistic models with the aim to refine the current value of risk.     

某型飞机投水作动装置解锁同步性影响因素分析

根据某型号飞机投水水箱三维数字样机及投水作动装置液压原理图,采用AMESim的液压库及3D Mechanical机械库搭建投水作动液压子系统模型,计算舱门开锁/上锁的时间和同步性。该模型的搭建考虑了影响投水性能的所有细节因素,为水箱作动系统结构的设计分析和优化提供了真实的仿真计算平台。在此基础上进一步分析了锁机构控制阀负载管路长度、主阀芯通径和阻尼孔大小对舱门开锁/上锁同步性的影响,其中管路长度和阻尼孔尺寸对同步性影响较大。上述分析结果为投水作动系统结构的进一步优化提供了理论依据。     

磨粒径向分布对电感式磨粒传感器测试结果的影响

根据电感平衡原理,设计了用于磨粒在线测量的电感式磨粒传感器.分析了传感器的测试原理和磨粒通过传感器线圈时径向分布对测试结果的影响.通过计算线圈内测试面的磁场分布,提出了提高线圈测试面磁场均匀性的设计准则.建立了磨粒位置偏离线圈中心时,磨粒磁化场的磁通求解模型.模型计算结果表明,磨粒径向位置的改变,使得线圈各横截面上磁化场的磁通发生了变化.当线圈达到一定长度后,磁化场的磁链变化很小.因此在保证传感器线圈测试面磁场均匀性和线圈长度的前提下,磨粒径向分布对测试结果的影响可忽略.研究结论为分析电感式磨粒传感器测试结果一致性和优化传感器的结构设计提供了理论依据.     

基于链路特性的卫星网络拓扑更新周期研究*

针对卫星网络拓扑更新时隙划分问题,提出了一种基于链路特性的卫星网络拓扑更新周期估算方法。首先对卫星网络拓扑更新周期进行建模,分别建立了卫星覆盖时间模型、链路长度特性模型和卫星网络拓扑更新周期估算模型;然后通过对不同星座卫星的仿真验证了此方法的有效性。该方法综合覆盖时间、时延抖动和链路长度特性三个因素对网络拓扑更新周期进行估算,提供了从链路特性到网络拓扑再到路由计算的研究视角,并通过网络拓扑这个桥梁将链路特性和路由计算连接起来,使其成为有机整体,对卫星网络的有效设计有一定的指导意义。     

对物联网工程专业教学体系建设的思考

在讨论物联网技术发展的社会背景、技术背景以及物联网技术特征与未来发展趋势的基础上,对物联网工程专业培养目标定位与课程体系建设时需要注意研究的四大关系,即物联网工程专业培养目标、教学体系与社会对专业人才需求的关系,物联网工程专业课程设置与成熟的计算机专业课程体系的关系,基本能力培养与不同学校办学特色的关系,理论教学与能力培养的关系问题进行了系统的讨论。提出物联网工程专业课程"课程精,实验强"的建设原则,并对物联网工程专业课程体系框架进行了初步的讨论。     

高微重力振动隔离系统激励器分配优化设计

为了满足高微重力振动隔离系统实时变化的控制器输出要求,同时也为了降低隔振系统激励器的功耗,对激励器分配组合进行了分配优化设计.介绍了激励器分配电流的计算方法,给定浮子质心作用力计算各种组合的激励器分配电流,对结果进行比较分析后确定出最优组合.通过给定相对位置、变化的质心作用力进行地面测试,结果表明了设计结果的合理性.     

Autonomous navigation during the final ascent of a spacecraft into the geostationary orbit. II. Simulation of operation of an integrated autonomous SC navigation and control system

This study continues the series of papers devoted to the approach to solving the problem of autonomous navigation of a spacecraft (SC) in a geostationary orbit at all stages of its lifecycle: final ascent, transfer to the operating longitude, remaining at the operating longitude, removal from the orbit, and burial. In [1], we formulated the concept of autonomous navigation of a spacecraft at the stage of its final ascent to a geostationary orbit. This stage is most complicated from the technical point of view, taking into account the nonlinearity of the applied mathematical models, the influence of uncontrollable factors of various physical nature, and the necessity of the application of promising hardware (electric low-thrust engine, onboard receiver of signals from global navigation satellite systems, intersatellite communication channels, etc.). Taking this into account, the only constructive method for proving the viability and efficiency (taking into account the requirements formulated by the customer who placed the order) of the developed concept of the autonomous navigation at the final ascent stage in the mathematical simulation of this process. The subject of this study is to demonstrate the capabilities of the developed concept of autonomous navigation from the point of view of achieving the required level of reliability and accuracy in solving the navigation problem at the final ascent stage. This demonstration is based on the analysis of the results of imitating the simulation of the process of a spacecraft’s final ascent to a geostationary orbit obtained using the specially developed software complex.     

Control of the angular orientation of the platform of a uniaxial wheeled module moving without slippage over an underlying surface

A method for controlling the angular orientation with respect to the horizon plane of the platform of a uniaxial wheeled module moving without slippage over the underlying surface is considered. For a module involving a one-axis gyroscope, a compensating flywheel, and a stabilizing weight, equations of motion are derived, which describe the module as a nonholonomic system due to the absence of slippage of its wheels over the underlying surface. The conditions for the “force of undisturbability” of the platform by the inertial forces upon its arbitrary translational-rotational motion and the conditions for “informational undisturbability” by the inertial forces of the accelometric sensor of the deviation of the platform from the horizon plane are determined. The analytical relationships determining the conditions for the absence of slippage of the wheels are found. By numerical simulation, rational values of the coefficient in the laws governing the moments of forces developed by the control elements of the structure are obtained. The effectiveness of these laws is confirmed by the results of simulating the control processes over the angular motion of the platform of the module along a typical trajectory of its motion over the underlying surface.     

惯性器件建模对GPS失锁段导航精度的影响

针对INS/GPS组合导航系统在GPS信号失锁的条件下导航精度恶化的问题,分析了惯性器件建模对导航精度的影响程度。通过对传统简化模型和考虑载体机动与环境因素的影响而建立的惯性器件完备模型的仿真,对两种模型在组合断开后的纯惯性导航的水平位置误差进行对比。结果表明相比简化模型相对完备模型可以将水平位置误差的精度提高53%,能有效解决INS/GPS组合导航系统因GPS信号失效后纯惯性系统的定位精度迅速恶化问题。     

Reconstruction of the corrective component of the transfer function of the interpolator in the process of calibration of the precision event timer

The peculiarities of the interpolation method based on digital signal processing are considered. It is shown that the transfer function of the interpolator may be represented by the composition of two functional components. A nonstatistical method of reconstruction of the form of the corrective component of the transfer function based on processing of the scatter diagram of the ordered pairs of the experimental and predicted data is investigated. It is shown that such pairs may be obtained in the process of periodic event flow timing with estimations of the time positions of the signal and the predetermined instants of the event occurrence being elements of the ordered pairs. The efficiency of the reconstruction method is illustrated by the experimental results.     

Synchronization in networks of linear agents with output feedbacks

The problem is considered of asymptotic synchronization by states in networks of identical linear agents in the application of the consensual output feedback. For the networks with fixed topology and without delay in the information transmission, on the basis of the passification theorem and the Agaev-Chebotarev theorem, the possibility is established of the provision of synchronization (consensus) of strong feedback under the assumption of the strict passification of agents and the existence of the incoming spanning tree in the information graph. In contrast to the known works, in which only the problems with the number of controls equal to the number of variables of the state of agents are investigated, in this work a substantially more complex case is considered, where the number of controls is less than the number of variables of the state, namely: the control is scalar. The results are illustrated by the example for the ring-shaped network of four dual integrators.     

Spot addressing for microarray images structured in hexagonal grids

In this work, an efficient method for spot addressing in images, which are generated by the scanning of hexagonal structured microarrays, is proposed. Initially, the blocks of the image are separated using the projections of the image. Next, all the blocks of the image are processed separately for the detection of each spot. The spot addressing procedure begins with the detection of the high intensity objects, which are probably the spots of the image. Next, the Growing Concentric Hexagon algorithm, which uses the properties of the hexagonal grid, is introduced for the detection of the non-hybridized spots. Finally, the Voronoi diagram is applied to the centers of the detected spots for the gridding of the image. The method is evaluated using spots generated from the scanning of the Beadchip of Illumina, which is used for the detection of Single Nucleotide Polymorphisms in the human genome, and uses hexagonal structure for the location of the spots. For the evaluation, the detected centers for each of the spot in the image are compared to the centers of the annotation, obtaining up to 98% accuracy for the spot addressing procedure.     

基于遥测技术的新型传感器柔性结构振动优化控制方法

为了提高新型传感器柔性结构振动抑制能力,提出基于遥测技术的新型传感器柔性结构振动优化控制方法。在速度坐标系、体坐标系下构建新型传感器柔性结构的振动动力学模型,采用卡尔曼滤波方法实现对新型传感器柔性结构振动参数的融合调节和小扰动抑制。采用气弹模态参数识别方法,进行新型传感器柔性结构的振动模态参数识别,提取新型传感器柔性结构振动特征量,采用遥测技术进行新型传感器柔性结构振动惯性参数识别,结合状态反馈调节方法进行稳定性控制,实现新型传感器柔性结构振动优化控制。仿真结果表明,采用该方法进行新型传感器柔性结构振动优化控制的自适应性较好,具有很好的振动抑制和控制能力。     

民间工艺对中国艺术设计史研究的意义

中国艺术设计史研究是对于中国造物行为中设计思维的仔细梳理与深度探索,中国传统造物的纷杂景观形成了设计学科框架建立的复杂性,造物行为的平民性也导致了中国艺术设计史研究的宽泛性,对于传统民间工艺的新型探究对中国艺术设计学科的确立与发展有着重要的当代意义。     

地下水流场的3维数值模拟及可视化研究——以常州-武进地区为例

通过研究常州一武进地区地下水流场的3维数值模拟，揭示了该地区产生地面沉降的主要成因。首先分析了该地区的水文地质条件，在此基础上建立了第Ⅱ承压含水层地下水流场的3维数值模型，采用3维有限差分法对其进行数值求解，并利用体视化中的混合体绘制算法，结合计算机动画技术实现了地下水流场的3维动态可视化。经过研究发现：该地区第Ⅱ承压含水层是最主要开采层，其长期超采是产生地下水降落漏斗与地面沉降的主要原因；地下水降落漏斗中心主要分布在沪宁铁路沿线工农业发达的人口密集区，地面沉降范围与地下水降落漏斗范围基本吻合，且沉降量和沉降速率与地下水位下降幅度和下降速度趋势一致；但是当地下水位出现大幅回升时，地面回弹现象并不明显，这表明地面沉降基本上是不可逆的。因此，该地区必须严格控制第Ⅱ承压含水层的地下水开采量，以免造成环境地质灾害的进一步恶化。     

基于导叶位置数据分析的刘家峡水电厂导叶立面间隙调整方法改进

在水电厂水轮机检修过程中,水轮机导叶立面间隙调整是一项重要而精细的工作,其主要目的是将水轮机24片矩形导叶两两相靠,调整为一个密不透水的圆筒状。传统导叶立面间隙调整方法虽然能满足调整完成后两两导叶立面间隙为零的技术要求,但因缺乏精确的反馈量和监视量,调整过程费时费力,同时可能造成导叶之间压紧程度不一的现象,对后续调整产生一定影响。通过采集机组检修前导水机构各项数据,导入三维建模软件进行精确建模,在模型中进行多项初始条件下进行水轮机导叶立面间隙模拟调整,并与检修前数据比较,得出该检修状态下导叶的标准位置。在现场实际调整过程中,根据不同水轮机导叶立面间隙分布情况、机组检修级别,结合导叶标准位置提出差异化水轮机导叶立面间隙调整策略,极大提高了水轮机导叶立面间隙[3]调整效率和精度,保证了机组运行安全性。     

An Exact Algorithm of Searching for the Largest Cluster in an Integer-Valued Problem of 2-Partitioning a Sequence

We analyze mathematical aspects of one of the fundamental data analysis problems consisting in the search (selection) for the subset with the largest number of similar elements among a collection of objects. In particular, the problem appears in connection with the analysis of data in the form of time series (discrete signals). One of the problems in modeling this challenge is considered, namely, the problem of finding the cluster of the largest size (cardinality) in a 2-partition of a finite sequence of points in Euclidean space into two clusters (subsequences) under two constraints. The first constraint is on the choice of the indices of elements included in the clusters. This constraint simulates the set of time-admissible configurations of similar elements in the observed discrete signal. The second constraint is imposed on the value of the quadratic clustering function. This constraint simulates the level of intracluster proximity of objects. The clustering function under the second constraint is the sum (over both clusters) of the intracluster sums of squared distances between the cluster elements and its center. The center of one of the clusters is unknown and defined as the centroid (the arithmetic mean over all elements of this cluster). The center of the other cluster is the origin. Under the first constraint, the difference between any two subsequent indices of elements contained in a cluster with an unknown center is bounded above and below by some constants. It is established in the paper that the optimization problem under consideration, which models one of the simplest significant problems of data analysis, is strongly NP-hard. We propose an exact algorithm for the case of a problem with integer coordinates of its input points. If the dimension of the space is bounded by a constant, then the algorithm is pseudopolynomial.