Research on reliability index of a large communication network with domain partition and interconnection

In order to indicate the performances of a large-scale communication network with domain partition and interconnection today, a kind of reliability index weighed by normalized capacity is defined. Based on the route rules of network with domain partition and interconnection, the interconnection indexes among the nodes within the domain and among the domains are given from several aspects. It is expatiated on that the index can thoroughly represent the effect on the reliability index of the objective factor and the subjective measures of the designer, which obeys the route rules of a network with domain partition and interconnection. It is discussed that the defined index is rational and compatible with the traditional index.

Reliability index algorithm of a sub-domain interconnection large communication network

The normalized weighted capacity reliability index of a sub-domain interconnection large scale communication network is defined and a new algorithm to calculate the reliability index is proposed, The proposed algorithm can be performed using logical or algebraic operation by means of computer-aided programming and the correctness of each key step is validated in detail. This paper takes the sub-domain interconnection symmetrical topologi- cal network for a typical example to calculate the network reliability index and verifies the correctness of the proposed algorithm us- ing the real measured statistical data. The real measured results are well in accordance with the results obtained by the proposed algorithm. The result shows that the proposed algorithm is a valid means to estimate the reliability index of a sub-domain intercon- nection large-scale communication network.

A PSO Based Multi-Domain Virtual Network Embedding Approach

This paper proposed a multi-domain virtual network embedding algorithm based on multi-controller SDN architecture. The local controller first selects candidate substrate nodes for each virtual node in the domain. Then the global controller abstracts substrate network topology based on the candidate nodes and boundary nodes of each domain, and applies Particle Swarm Optimization Algorithm on it to divide virtual network requests. Each local controller then embeds the virtual nodes of the divided single-domain virtual network requests in the domain, and cooperates with other local controllers to embed the inter-domain virtual links. Simulation experimental results show that the proposed algorithm has good performance in reducing embedding cost with good stability and scalability.

Evolution of a protein domain interaction network

In this paper, we attempt to understand complex network evolution from the underlying evolutionary relationship between biological organisms. Firstly, we construct a Pfam domain interaction network for each of the 470 completely sequenced organisms, and therefore each organism is correlated with a specific Pfam domain interaction network; secondly, we infer the evolutionary relationship of these organisms with the nearest neighbour joining method; thirdly, we use the evolutionary relationship between organisms constructed in the second step as the evolutionary course of the Pfam domain interaction network constructed in the first step. This analysis of the evolutionary course shows： （i） there is a conserved sub-network structure in network evolution; in this sub-network, nodes with lower degree prefer to maintain their connectivity invariant, and hubs tend to maintain their role as a hub is attached preferentially to new added nodes; （ii） few nodes are conserved as hubs; most of the other nodes are conserved as one with very low degree; （iii） in the course of network evolution, new nodes are added to the network either individually in most cases or as clusters with relative high clustering coefficients in a very few cases.

Virtual 5G Network Embedding in a Heterogeneous and Multi-Domain Network Infrastructure

The pursuit of the higher performance mobile communications forces the emergence of the fifth generation mobile communication(5G). 5G network, integrating wireless and wired domain, can be qualified for the complex virtual network work oriented to the cross-domain requirement. In this paper, we focus on the multi-domain virtual network embedding in a heterogeneous 5G network infrastructure, which facilitates the resource sharing for diverse-function demands from fixed/mobile end users. We proposed the mathematical ILP model for this problem.And based on the layered-substrate-resource auxiliary graph and an effective six-quadrant service-type-judgment method, 5G embedding demands can be classified accurately to match different user access densities. A collection of novel heuristic algorithms of virtual 5G network embedding are proposed. A great deal of numerical simulation results testified that our algorithm performed better in terms of average blocking rate, routing latency and wireless/wired resource utilization, compared with the benchmark.

Improved control for distributed parameter systems with time-dependent spatial domains utilizing mobile sensor-actuator networks

A guidance policy for controller performance enhancement utilizing mobile sensor-actuator networks （MSANs） is proposed for a class of distributed parameter systems （DPSs）, which are governed by diffusion partial differential equations （PDEs） with time-dependent spatial domains. Several sufficient conditions for controller performance enhancement are presented. First, the infinite dimensional operator theory is used to derive an abstract evolution equation of the systems under some rational assumptions on the operators, and a static output feedback controller is designed to control the spatial process. Then, based on Lyapunov stability arguments, guidance policies for collocated and non-collocated MSANs are provided to enhance the performance of the proposed controller, which show that the time-dependent characteristic of the spatial domains can significantly affect the design of the mobile scheme. Finally, a simulation example illustrates the effectiveness of the proposed policy.

Estimate of Multiple Attracing Domains for Cohen-Grossberg Neural Network with Distributed Delays

In this paper, we present multiplicity results of exponential stability and attracting domains for Cohen- Grossberg neural network (CGNN) with distributed delays. We establish new criteria for the coexistence of equilibrium points and estimate their attracting domains. Moreover, we base our criteria on co-efficients of the networks and the derivative of activation functions within the attracting domains. It is shown that our results are new and complement corresponding results existing in the previous literature.

分布式软件定义网络中多域流量工程的路由优化方法

针对分布式软件定义网络(software-defined networking,SDN)中流量管理调度不均衡的流量工程问题,提出一种基于负载均衡的多控制域流量路由优化的解决方案。首先分析控制消息流量的组成、域内通信及域间通信规则;然后基于4种控制消息定义控制链路流量的构成,明确链路承载流量分为控制消息流量和业务流量,建立平衡控制器负载和最小化最大链路利用率的优化模型;最后基于域内通信和域间通信提出两层路由算法。为提高模型求解精度,进一步提出改进离散萤火虫算法求解最优路由。结合ABILENE网络和GEANT网络,分析控制消息流量、控制器负载和链路负载等评价指标。实验结果表明,优化模型能有效实现控制器和链路负载均衡,控制消息流量是流量工程重要组成部分。相比集中控制模式,扁平分布式控制模式的平均控制器负载降低47.3%,最大链路利用率相差不超过15%。

基于改进Faster R-CNN的域自适应红外目标检测方法

为充分利用当前大量注释的RGB图像数据提高热红外图像的目标检测性能,提出一种基于深度学习模型的无监督域自适应(UDA)方法。对Faster RCNN骨干网络进行改进,增强感受野表征能力,优化目标框的正负样本不平衡问题和回归机制。为解决从RGB域到红外域迁移过程中不同层面的域偏移问题,在改进Faster RCNN架构的不同网络层和不同阶段引入图像级和实例级特征分布对齐。实验结果表明,在多光谱公开数据集KAIST和FLIR-ADAS上,所提UDA方法分别实现了73.35%和77.66%的全类平均精度(mAP结果),显著提高了恶劣照明条件下的目标检测性能。

基于资源感知的多域服务功能链编排成本优化

网络功能虚拟化技术的兴起使得实例化为服务功能链(SFC)的网络服务能够共享基底网络,缓解了传统网络体系结构僵化的问题.然而,网络中大量服务请求给多域SFC编排带来了新的挑战.首先由于域内网络资源信息及内部策略的保密性,使得多域SFC的编排更为复杂.其次多域SFC编排要确定最佳候选编排域集,先前的研究较少考虑域间负载的均衡性,对服务接受率造成了消极影响.此外跨网络域编排服务请求对服务的成本和响应时间提出了更严格的要求.为解决上述挑战,在本文中,我们首先针对多域网络隐私性需求,提出了域级图的构造方法;然后基于域间负载均衡提出了域权重的计算方法进行SFC编排域的选择;最后,针对多域网络成本和响应时间需求,提出编排算法.实验结果表明,提出的算法有效地权衡了平均服务成本和接受率,并且在服务平均响应时间方面也得到了优化.

基于时域划分的网络流量预测方法

网络流量的预测一般通过建立相应的分析模型分析时序序列的发展过程及趋势,缺乏对网络流量波动空间和周期特征的分析,无法对短时突变流量及短周期流量进行精准预测。为了提高网络流量的预测效果,提出一种基于时域特征分析的网络流量预测方法。该方法通过分析网络流量的周期特征,建立时域划分模型,使具有相同趋势及波动空间的网络流量重组,突出短时突变流量和周期趋势特征,增强数据规律,以提高网络流量预测精度。选取反向传播(BP)神经网络、长短期记忆(LSTM)神经网络及小波神经网络(WNN)模型,采用均方误差(MSE)作为衡量标准,分别验证时域划分模式和全时域模式网络流量预测效果。结果表明,时域划分模式时BP神经网络和WNN的MSE相比全时域模式更低,其中时域划分模式BP神经网络的MSE降低为全时域模式时的1/24,说明通过分析网络流量数据建立的时域划分模型能够提高网络流量预测性能,为大规模互联网环境下的网络流量预测分析提供一种分而治之的方法。

融合双域特征均衡的遥感图像道路提取

当前遥感图像道路提取模型仍在很大程度上受道路植被遮挡所影响,导致网络模型对道路信息误判。为此,基于双域特征均衡提出了一种不受遮挡物影响的道路提取方法,高效地实现植被遮挡下的道路提取。具体而言,提出了一种新的道路提取卷积神经网络,该网络由去除遮挡子网络和道路提取子网络组成。在去除遮挡子网络中嵌入一个分层卷积模块用于提取输入图像的深层结构特征和浅层纹理特征,以及双域均衡模块用于特征还原,以此去除目标道路上的遮挡物。道路提取子网络用于对去除遮挡后的道路结构进行精细的分割,得到准确性更高的道路提取结果。通过在四川西南农村地区的遥感数据集上进行大量实验,结果显示基于双域特征均衡的方法相较于其他遥感图像道路提取方法在像素精确度(Overall Accuracy, OA)和交并比(Intersection over Union, IoU)指标上达到了最高,分别是98.16%和85.38%。

基于生成对抗网络的小波域自适应图像分割技术

当图像对比度低或者光照条件复杂时,图像目标形状、颜色等特征都具有很高的变异性,难以准确地识别目标边界,导致图像分割结果中目标区域与真实标注的重合程度较低。为此,文章研究基于生成对抗网络的小波域自适应图像分割技术。该技术利用小波域分析基函数,将图像从空间域转换为模糊集域;考虑图像对比度,计算图像变换的扩散强度与各向同性扩散系数;采用反模糊变换函数恢复图像中存在的模糊效应,获取目标边缘增强的图像,计算图像像素之间的相似度;通过引入距离信息,计算分割图像的相对熵和权值,对生成对抗网络进行优化处理,实现图像的自适应分割。实验结果表明,所提技术可以对图像进行精准分割,并保留丰富的细节信息,平均重叠率达到了96.3%,分割准确性较高,这表明该技术在图像分割任务中具有较高的可靠性,为后续的图像处理任务提供高质量的输入数据。

架空配电线路故障电弧的电磁辐射特性及故障定位应用

针对架空配电线路电弧接地故障点定位难题,该文研究架空配电线路故障电弧的电磁辐射特性,探索基于电磁辐射信号的电弧故障定位方法的可行性。通过10 k V配网真型故障模拟试验平台,分析接地电弧电磁辐射的时域与频域特性及传播衰减规律,结果表明:电弧电流的电磁辐射特征频段为20~30 MHz,该特征频段不会受到中性点接地方式、电弧接地介质与线路结构参数的显著影响,且特征频段内辐射信号在传播过程中衰减较慢。在此基础上,设计一种小型化三角形单极子–环形组合平面天线,工作频率为20~500 MHz。利用自制天线开展小型电弧故障定位实验,为后续配网电弧故障定位的应用研究提供基础。

基于偏正结构表示的加工命名实体识别方法

制造企业积累大量的零件加工经验多以文本形式存在,如何从文本中挖掘出高质量的零件加工知识是个尚待解决的问题。针对待识别实体存在的偏正结构特征,导致实体边界界定模糊的问题,提出一种多网络协调的中文命名实体识别方法。在BERT生成字向量的过程中,通过领域自适应方法,提高字向量对工艺实体的表征能力,同时,在BiLSTM-CRF模型中引入注意力机制和多门控制的混合专家网络捕获上下文特征与实体信息。实验表明,较于当前主流的命名实体识别模型,该文提出的方法对机械零件加工实体识别的F1值达到80.15%,取得优于其他模型的最好性能。

中性点柔性接地配电网故障相恢复电压暂态时域特征分析

配电网接地故障过零熄弧后的电压暂态恢复特性决定了系统过电压水平及电弧重燃特性,目前,中性点柔性接地配电网故障熄弧后暂态恢复电压变化机理尚不明确,为此建立柔性接地配电网接地故障暂态等值电路,理论解析故障过零熄弧后故障恢复电压的时域表达式。在此基础上,对比分析配电网谐振接地与柔性接地方式下,系统参数变化对故障相恢复电压暂态峰值与恢复速度的影响,揭示暂态时间尺度下故障相恢复电压特征随注入零序电流值与电流注入时机的变化规律,阐明通过中性点注入可控零序电流抑制故障暂态过电压的机理。在PSCAD/EMTDC仿真环境与10 kV真型配电网实验场中模拟各种运行和故障工况,仿真与真型实验结果均验证柔性接地配电网故障相恢复电压时域解析特征与变化规律的正确性。

面向空天地一体化网络的抗干扰技术研究

空天地一体化网络是实现全域通信和提供网络互联互通服务需求的重要基础设施之一。在未来的强对抗干扰环境中,确保其数据传输的有效性与可靠性对于维护国家安全具有重要意义。针对空天地一体化网络的对抗性的环境特点,探讨了在时频域和空域实现抗干扰的潜在应用与关键技术,并提出了对空天地一体化网络的综合思考。最后展望未来,以期为后续研究和实际应用提供方向性指导。

跨域网络使用行为对工作家庭关系的影响——基于潜在剖面分析

基于资源保存理论,运用潜在剖面分析(latent profile analysis,LPA)方法,对742名员工的跨域网络使用行为进行了类别划分,并进一步分析了不同类别的跨域网络使用行为对工作家庭关系的影响差异.研究结果表明,跨域网络使用行为可分为3种,分别命名为回避型跨域网络使用行为、适度型跨域网络使用行为和活跃型跨域网络使用行为.其中,活跃型跨域网络使用行为员工的工作家庭关系水平最高;同时,与工作家庭冲突相比,跨域网络使用行为对工作家庭增益的影响更大.

智能网联汽车多域电子电气架构技术发展研究

智能网联作为汽车行业的重要发展趋势,是实现汽车行业新四化技术改革的关键性支撑技术。创新升级智能网联汽车操作系统核心技术,不但是落实国家战略要求,实现汽车制造强国目的,更是掌握自主研发核心技术,打破发达国家对我国技术封锁的重要途径。现阶段而言,随着汽车的智能化程度越高、功能越丰富,其对操作系统的要求也越来越高,多域电子电器架构技术的重要性愈发凸显。基于此,文章在智能网联汽车多域电子电器架构技术的基础上,对多域电子电器架构技术发展现状进行了分析,指出了当前我国智能网联汽车电子电器架构技术的优势,并对智能网联汽车电子电器架构技术发展趋势进行了探讨。

夏代王朝体制的建立与内外服制的形成

尧舜禹时代洪水迫使长江、黄河、淮河、济河下游的人群向中原迁徙,奠定了中原的中心地位。在治水的过程中,人们逐渐建立起跨地域跨血缘的政治联盟,并向早期国家发展。禹和启在早期国家的基础上,经过强化天下共主观念,建立起中央王朝。早期中央王朝缺乏强制力和控制力,只能依据地域和融合程度确定中央与地方的关系,由此形成了内外服制。