Energy-efficient low-latency virtual cluster synchronization algorithm based on SMAC protocol in wireless sensor networks

The MAC protocol design for wireless sensor networks has been researched and developed for decades. SMAC protocol is a famous energy-efficient MAC protocol. Based on SMAC protocol, we find that the boundary nodes in the cluster-shaped synchronization structure bring energy consumption seriously, and provide a virtual cluster aggregation (VCA) algorithm. Because the bounder node follows multiple schedules in one cycle, it may deplete earlier and cause segmentation in wireless sensor networks. The algorithm reduces energy consumption of boundary nodes and extends the lifetime of entire sensor network by merging different virtual clusters, but increases the data transmission delay. Because the sensor nodes have the fixed duty cycle, the larger the coverage area of network is, the greater the data transmission delay increases. We propose the dynamic duty cycle (DDC) algorithm to solve this effect. When the network load and data transmission delay increase, the DDC algorithm exponentially changes the duty cycle of the node to reduce latency. The simulation results show that the performance of SMAC with the VCA and DDC algorithm obtains improvement significantly.

Scalable group management in large-scale virtualized clusters

To save cost, more and more users choose provision resources at the granularity of virtual machines in cluster systems, especially data centres. Maintaining a consistent member view is the foundation of reliable cluster managements, and it also raises several challenge issues for large scale cluster systems deployed with virtual machines （which we call virtualized clusters）. In this paper, we introduce our experience in design and implementation of scalable member view management on large-scale virtual clusters. Our research contributions include three-aspects ： 1 ） we propose a scalable and reliable management infrastructure that combines a peer-to-peer structure and a hierarchy structure to maintain a consistent member view in virtual clusters; 2 ） we present a light-weighted group membership algorithm that can reach the consistent member view within a single round of message exchange; 3 ） we design and implement a scalable membership service that can provide virtual machines and maintain a consistent member view in virtual clusters. Our work is verified on Dawning 5000A, which ranked No. 10 of Top 500 super computers in November, 2008.

A Cluster-Based Virtual Cooperative MIMO Transmission Scheme

The most essential issue is to ensure the reliability of data transmission during wireless communication and reduce energy consumption of the network for supervising the environmental state using wireless sensor network(WSN).Here,a cluster-based virtual cooperative MIMO transmission scheme(CVCM) is suggested,The proposed scheme involves optimization of cooperative nodes and the modulation speed dynamically as per the distance space the cluster head and the sink node,in order to minimize the communication energy consumption of each virtual MIMO unit and the convergence node,thereby reducing the capacity consumption of the entire network.Simulation and experimental results demonstrate the effectiveness of CVCM in reducing network energy consumption,increasing the network lifetime and improving data reception performance of the base station.

A Virtual Router Cluster System Based on the Separation of the Control Plane and the Data Plane

This paper proposes a virtual router cluster system based on the separation of the control plane and the data plane from multiple perspectives,such as architecture,key technologies,scenarios and standardization.To some extent,the virtual cluster simplifies network topology and management,achieves automatic conFig.uration and saves the IP address.It is a kind of low-cost expansion method of aggregation equipment port density.

A Modeling Framework Based on Enterprises Cluster for Virtual Enterprise

As a new type of organization form,virtual enterprise is believed to have many theoretical advantages,but these advantages have not been fully shown in practice yet.The paper intends to analyze the causes and to propose ideas to solve the problem.Starting from the characteristics of virtual enterprise,the paper analyzes the factors hindering the practice of the virtual enterprises,evaluates the lack of existing models,and then comes to the conclusion that a unified, simplified model is more conducive to the realization of virtual enterprise according to the actual situation.Learning from the mechanism of enterprises cluster,the paper suggests a modeling framework for the new idea of virtual enterprise which is effective in operation.The main contributions of this modeling include:constitute a standardized operating platform to overcome the prime obstacle from the diversity of the partners for the practice of virtual enterprise;and set up a collaboration layer as the buffer mechanism between the partners and the database.

VIA(Virtual Interface Architecture)上的软件DSM系统实现和性能

在由高性能PC搭建的Linux机群系统上 ,传统的网络接口体系结构引入了巨大的软件处理开销 ,无法满足虚拟共享存储并行应用对通信带宽、延迟和进程间同步的需求 .用户级网络接口标准———虚拟接口体系结构(VirtualInterfaceArchitecture ,VIA)与传统的网络接口体系结构相比 ,在软件协议开销、通信关键路径上操作系统的干预程度、通信和计算的重叠程度以及实现零拷贝等方面 ,具有明显的优势 .通过在传统网络通信接口和VIA通信接口上虚拟共享存储系统的性能对比 ,采用VIA网络接口体系结构可有效地提高虚拟共享存储系统的性能和可扩展性 .

基于Cluster的多服务器容错与切换技术的研究

本文对Cluster集群技术进行了讨论 ,着重分析了基于Cluster的多服务器容错与切换技术 ,同时给出了一个基于Cluster的双服务器容错与切换的应用实例。

Constructing global view with an ontology-based method for information sharing in the virtual organization

The problem of constructing global view of heterogeneous information sources for information sharing is becoming more and more important due to the availability of multiple information sources within the virtual organization. Global view is defined to provide a unified representation of the information in the different sources by analyzing concept schemas associated with them and resolving possible semantic heterogeneity. An ontology-based method for global view construction is proposed. In the method, （ 1 ） Based on the formal ontologies, the concept of semantic affinity is introduced to assess the level of semantic relationship between information classes from different information sources; （2） Information classes are classified by semantic affinity levels using clustering procedures so that their different representations can be analyzed for unification; （3） Global view is constructed starting from selected clusters by unifying representation of their elements. The application example of using the method in the joint-aerial defense organization is illustrated and the result shows that the proposed method is feasible.

ApplianceBricks: A Scalable Network Appliance Architecture for Network Functions Virtualization

Network Functions Virtualization(NFV) is an attempt to help operators more effectively manage their networks by implementing traditional network functions embedded in specialized hardware platforms in term of virtualized software instances. But, existing novel network appliances designed for NFV infrastructure are always architected on a general-purpose x86 server, which makes the performance of network functions limited by the hosted single server. To address this challenge, we propose ApplianceB ricks, a novel NFV-enable network appliance architecture that is used to explore the way of consolidating multiple physical network functions into a clustered network appliance, which is able to improve the processing capability of NFV-enabled network appliances.

Energy-Efficient and Coverage-Aware Clustering in Wireless Sensor Networks

Energy efficiency and sensing coverage are essential metrics for enhancing the lifetime and the utilization of wireless sensor networks. Many protocols have been developed to address these issues, among which, clustering is considered a key technique in minimizing the consumed energy. However, few clustering protocols address the sensing coverage metric. This paper proposes a general framework that addresses both metrics for clustering algorithms in wireless sensor networks. The proposed framework is based on applying the principles of Virtual Field Force on each cluster within the network in order to move the sensor nodes towards proper locations that maximize the sensing coverage and minimize the transmitted energy. Two types of virtual forces are used: an attractive force that moves the nodes towards the cluster head in order to reduce the energy used for communication and a repulsive force that moves the overlapping nodes away from each other such that their sensing coverage is maximized. The performance of the proposed mechanism was evaluated by applying it to the well-known LEACH clustering algorithm. The simulation results demonstrate that the proposed mechanism improves the performance of the LEACH protocol considerably in terms of the achieved sensing coverage, and the network lifetime.

数字文化产业虚拟集群的形成机理及其系统动力学分析

因现代信息技术与互联网平台属性加持,数字文化产业虚拟集群相较于传统地理集群,存在更强的集群正外部性、规模经济效应、知识溢出效应和产业分工效应,即数字文化产业虚拟集群的形成存在发展规律与内在逻辑上的必然。基于系统动力学模型,发现良好的社会经济环境、数字基础设施、升级的文化消费需求、技术要素、人力资本、文化资源禀赋以及政策因素,在“经济—资源—政策”系统内形成了显著的正反馈作用,这也是数字文化产业虚拟集群最终形成的决定性动因。我国应继续鼓励并推动文化产业融合,积极拓展虚拟集群业务功能,努力完善数字文化内容版权保护机制,强化虚拟集群的平台治理水平,引导数字文化产业虚拟集群的价值导向,从而更好地释放集群的文化价值与经济影响。

Electricity-Carbon Interactive Optimal Dispatch of Multi-Virtual Power Plant Considering Integrated Demand Response

As new power systems and dual carbon policies develop,virtual power plant cluster(VPPC)provides another reliable way to promote the efficient utilization of energy and solve environmental pollution problems.To solve the coordinated optimal operation and low-carbon economic operation problem in multi-virtual power plant,a multi-virtual power plant(VPP)electricity-carbon interaction optimal scheduling model considering integrated demand response(IDR)is proposed.Firstly,a multi-VPP electricity-carbon interaction framework is established.The interaction of electric energy and carbon quotas can realize energy complementarity,reduce energy waste and promote low-carbon operation.Secondly,in order to coordinate the multiple types of energy and load in VPPC to further achieve low-carbon operation,the IDR mechanism based on the user comprehensive satisfaction(UCS)of electricity,heat as well as hydrogen is designed,which can effectively maintain the UCS in the cluster within a relatively high range.Finally,the unit output scheme is formulated to minimize the total cost of VPPC and the model is solved using theCPLEX solver.The simulation results showthat the proposed method effectively promotes the coordinated operation among multi-VPP,increases the consumption rate of renewable energy sources and the economics of VPPC and reduces carbon emissions.

无线传感器网络中基于量子郊狼优化的分簇路由协议

为进一步均衡无线传感器网络能耗,延长网络寿命,本文提出了一种基于量子郊狼优化的分簇路由协议。基于量子郊狼优化的分簇路由协议服务于静态部署网络,使用结合量子计算与郊狼优化算法优势的量子郊狼优化动态集中式搭建簇,并在簇有效期内综合考虑传感器能量、到基站距离和到虚拟簇首距离3种因素动态分布式轮换簇首,再通过簇首本地广播的形式动态分布式搭建数据中继传输链。仿真结果表明:与分布式低能耗自适应集群层次协议、基于粒子群优化模糊C均值的分簇路由算法和能量有效非均匀分簇路由协议相比,基于量子郊狼优化的分簇路由协议能有效平衡网络负载与能耗,在保证网络服务质量的同时最大化延长网络寿命。

高校虚拟仿真实验课程应用评价研究

虚拟仿真实验课程,是国家一流课程的重要组成部分,是高校实验教学的重要资源,是信息技术融入实验教学的基本体现。虚拟仿真实验课程的应用评价对于促进该课程的可持续发展意义深远。根据教育部已认定的面向高校和社会免费开放并提供教学服务的虚拟仿真实验课程,基于其应用数据,采用K-means聚类方法和多项逻辑回归方法,分析其应用活跃度和影响因素,发现不同课程群组的应用特征和影响因素,可为改进课程提供建议,可为课程评价提供依据。

一种无需指定船舶位置的新型船舶大规模自主编队方法

[目的]针对船舶大规模编队通信量大、编队速度慢、不便于扩充等问题,提出一种新型的虚拟壁面编队方法。[方法]使用局部通信,根据自然规律,设定虚拟作用力驱使船舶向目标位置集合,并通过虚拟壁面调整队形,从而实现船舶编队的目的。[结果]结果表明,所提方法能够按照“就近原则”快速地完成编队,通信量低且不随编队规模而增加。通过对船舶编队的静态、动态、旋转、缩放和避障的仿真验证了这种算法的有效性。[结论]所提虚拟壁面法具有通信量低、编队速度快、扩充简单等优势,在船舶大规模编队中具有明显优势。

A Centralized Algorithm for Assigning MDC Video Application in Virtual Network

Providing services on demand is a major contributing factor to drive the increasingly development of the software defined network. However, it should supply all the current popular applications before it really attains widespread development. Multiple Description Coding(MDC) video applications, as a popular application in the current network, should be reasonably supported in this novel network virtualization environment. In this paper, we address this issue to assign MDC video application into virtual networks with an efficient centralized algorithm(CAMDV). Since this problem is an NP-hard problem, we design an algorithm that can effectively balance the user satisfaction and network resource cost. Previous work just builds a global multicast tree for each description to connect all the destination nodes by breadth-first search strategy or shortest path tree algorithm. But those methods could not achieve an optimal balance or a high-level user satisfaction. By introducing the hierarchical clustering scheme, our algorithm decomposes the whole mapping procedure into multicast tree construction and multipath description distribution. A serial of simulation experiments show that our centralized algorithm could achieve a better performance in balancing the user satisfaction and average mapping cost in comparison with its rivals.

基于改进风光场景聚类联合虚拟储能的源网荷储低碳优化调度

针对源网荷储优化调度时分布式电源的间歇性引起主动配电网节点电压波动以及有功网损增加等问题,提出一种改进风光场景聚类联合虚拟储能的源网荷储低碳优化调度方法。首先,为有效应对风光出力不确定的挑战,提出一种基于密度噪声应用空间聚类(density-based spatial clustering of applications with noise,DBSCAN)的迭代自组织数据分析算法(iterative self-organizing data analysis techniques algorithm,ISODATA),并以DB指数、Dunn指数和轮廓系数对风光场景聚类效果的优劣进行评价。其次,引入阶梯式碳交易机制,建立以主动配电网综合运行成本最低为目标的优化调度模型。同时,提出用户参与满意度和电网依赖度两种运行评价指标。最后,在IEEE 33节点系统上进行算例仿真分析,结果验证了DBSCAN-ISODATA算法的合理性。并且所提低碳优化调度方法能够有效降低系统碳排放量与运行成本,实现了主动配电网低碳经济稳定运行。

风电集群汇集的共享储能虚拟惯量补偿控制策略

针对大规模风电并网导致系统惯量削弱问题,提出风电集群汇集的共享储能虚拟惯量补偿控制策略。首先,计算风电集群惯量削弱量及共享储能电站的惯量补偿目标;然后,根据惯性响应的基本物理意义,定义储能装置的虚拟惯量;接着,探明其时变特性,求解储能虚拟惯量时域过程,确定储能电站以及各储能单元虚拟惯量补偿目标,提出各储能单元补偿目标动态设置控制参数的控制策略;最后,通过Matlab/Simulink仿真,验证了所提策略在不同储能配置容量、不同风电渗透率下均具有良好控制效果和适应性。

文化产业虚拟集群对我国省域网络文化软实力的影响

文化产业虚拟集群是文化企业成员基于数字技术,在信息共享与价值交换理念下形成的网络平台组织。数智时代,文化产业虚拟集群在数据要素效率倍增的中介作用下,能够借助展示平台、承载形式、表现方法、传播途径等实现网络文化软实力的提升。为此,以爱奇艺虚拟集群为例,选择空间杜宾双重差分模型佐证了上述观点。同时研究还发现,文化产业虚拟集群对周边省域网络文化软实力的提升存在“虹吸效应”,且相较于中西部地区,文化产业虚拟集群对东部地区的网络文化软实力影响更加显著。综上,我国应努力协调区域间的数字文化资源配置、改良文化软实力传播渠道、强化文化产品的精神属性与文化认同,从而赓续文化传承,实现我国文化软实力与影响力的进一步增强。

大数据消冗技术下虚拟网络聚类特征层次布局算法

针对在虚拟网络布局过程中,存在大量重复特征与相关性较少的特征,影响其布局效率的问题,提出了大数据消冗技术下虚拟网络聚类特征层次布局算法。利用加权无向图方式建立虚拟网络图,通过社团划分虚拟网络社团结构,在保持原有特征不变的前提下,最大限度消除虚拟网络聚类特征,得到相关性较大特征;根据库伦力的斥力增加各社团之间距离,采用胡克定律的引力缩小网络节点与中心点之间距离,结合共轭梯度(FR:Flecher-Reeves)算法调整虚拟网络聚类特征层节点的斥力与引力之间关系,实现层次布局算法。实验结果表明,所提算法能更加清晰展现出各社团内部结构特征,且布局用时最短。