面向网络资产漏洞评估的设备指纹搜索引擎构建方法

网络资产漏洞评估技术对于梳理互联网资产、实现网络资产漏洞安全管理起到十分重要的作用.已有方法因无法有效获取设备指纹信息而产生评估结果准确度低、功能单一等问题.为此,本文提出一种面向网络资产漏洞评估的设备指纹搜索引擎构建方法,具有多接口、交互性强、减少网络冗余探测的优势.本文通过统计和评估真实网络中的服务器类型、HTTPS协议漏洞来验证方法的高效性.     

基于神经网络的飞艇非线性鲁棒滑模飞行控制

为了提高飞艇飞行的鲁棒性能,针对飞艇水平面受扰运动提出了一种基于非线性滑模的鲁棒神经网络飞行控制方案。对于飞艇模型中的不确定性,采用神经网络进行逼近,同时对神经网络权值进行在线调整以达到在线逼近的目的。为了有效地处理外部时变干扰对飞艇飞行控制的影响,将参数自适应、神经网络输出与滑模控制相结合设计了飞艇的鲁棒飞行控制。最后,通过飞艇水平面运动控制验证了本文所提出的飞艇鲁棒飞行控制方法的有效性。     

Robust video multicast with joint network coding and video interleaving

In this work, we propose a cross-layer solution to robust video multicast in erasure networks based on random linear network coding (RLNC) in the network layer and video interleaving (VI) in the application layer, and call it the joint RLNC-VI scheme. In the RLNC implementation, we partition one video coding unit (VCU) into several priority levels using scalable properties of H.264/SVC video. Packets from the same priority level of several VCUs form one RLNC generation, and unequal protection is applied to different generations. RLNC provides redundancy for video packets in the network layer and has proved to be useful in a multicast environment. Then, we propose a new packet-level interleaving scheme, called the RLNC-facilitated interleaving scheme, where each received packet corresponds to a new constraint on source packets. As a result, it can facilitate the RLNC decoding at the destination node. Furthermore, we study the problem of optimal interleaving design, which selects the optimal interleaving degree and the optimal redundancy of each generation. The tradeoff between delay and received video quality due to the choice of different VCUs is also examined. It is shown by simulation results that the proposed RLNC-VI scheme outperforms the pure RLNC method for robust video multicast in erasure networks. This can be explained by two reasons. First, the VI scheme distributes the impact of the loss (or erasure) of one VCU into partial data loss over multiple neighboring VCUs. Second, the original video content can be easily recovered with spatial/temporal error concealment (EC) in the joint RLNC-VI scheme.     

A Broadband High Gain Tapered Slot Antenna for Underwater Communication in Microwave Band

Named Data Networking (NDN), an emerging communication model in the content centric networks, has recently presented a solid framework for the future Internet. The NDN exploits content name instead of host name (IP address) and content caching. These features make NDN particularly efficient in networks with intermittent connectivity and dynamic topologies such as mobile ad hoc networks (MANETs). Due to the structure of NDN nodes, design of forwarding strategies has a vital impact on the network performance. In this paper, we propose a new forwarding strategy: redundancy elimination forwarding (REF). In REF, the NDN node structure and the operation of the data structures are modified. These modifications improve network performance in terms of throughput, overhead and resource requirements. REF strategy is simulated in different scenarios based on ndnSIM and the results demonstrate that it provides robust performance for various environments.

     

Cooperative network solution and implementation for emergency applications with enhanced position estimation capability

This paper proposes a cooperative network topology for emergency applications which comprises of incident scene networks (ISN) and external area networks. Both base stations and rescuers in ISN are modeled as nodes with the capabilities of software defined radio and signal processing. A worldwide interoperability for microwave access-based emergency protocol is proposed with which rescuers can estimate their geo-locations via time difference of arrival based on more than four known base stations coordinates. A comparative study of state-of-the-art position estimation methods have been carried out for the proposed cooperative network topology to select the most robust method. Hardware results for the most robust position estimation method without/with multipath mitigation have been implemented and presented to estimate the location of the rescuer.     

Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks

Wireless sensor networks （WSNs） consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization （BACRIL） in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500.     

Performance Optimization Based on Compressive Sensing for Wireless Sensor Networks

A routing algorithm, based on a dual cluster head redundant mechanism combined with compressive sensing data fusion algorithm, is proposed to improve reliability and reduce data redundancy of the industrial wireless sensor networks. The Dual cluster head alternation mechanism is adopted to balance the energy consumption of cluster head nodes. Through the compressive sensing data fusion technology to eliminate redundancy, effectively improve the network throughput of the sensor network. The simulation results show that the proposed algorithm is able to enhance the networks performance, significantly reduces the number of lost packets and extend the network’s lifetime.     

Securing network availability

We live in a world that relies increasingly on its communications infrastructure. Network availability problems affect customers and their businesses, and can damage trust in the resilience of the network. As such, ensuring that networks are robust, reliable and resistant to external attack is a key part of network design. In this paper we examine some of the vulnerabilities and issues posed by connectionless packet networks and outline potential solutions to these problems. A key theme throughout this discussion is the separation of the data and control planes. Within the PSTN, the control network is physically separate from the data circuits. This, along with tightly controlled and limited network interfaces, makes certain types of attack impossible. Unfortunately, with a connectionless packet network, this type of separation will never be completely possible. Further, the nature of network interworking is changing as we move towards a world of increasing service diversity and dynamic, ad hoc networks.     

A neural network with O(N) neurons for ranking N numbers in O(1/N) time

In this paper, we propose a neural network for ranking a given set of N numbers in O(1/N) time. The ordering of a set of numbers based on their relative magnitudes, which is analogous to sorting, is a fundamental operation in many algorithms. In comparison with other sorting networks reported in the literature, the proposed network requires fewer neurons, and fewer interconnections between neurons. The interconnections use nonlinear synapses which are composed of comparators, and do not require any weighted interconnections between neurons, as used in conventional neural networks. The proposed network has many applications, including as a component of self-organizing feature maps and other systems where sorting is a frequent operation.     

Design and analysis of defect tolerant hierarchical sortingnetworks

A hierarchical modular sorting network which achieves a balance in area-time cost between the odd-even transposition sort and the bitonic sort is presented. It consumes less hardware than a single-level odd-even sorter and reduces the wire complexity of the bitonic sorter in VLSI or WSI (wafer-scale integration) implementation. The optimal number of levels in the hierarchy is evaluated, and the sorting capability of each level is derived so as to minimize the hardware overhead. The hierarchical sorting network is very regular in structure and hence defect tolerance capability can be included more easily than in any existing sorting network with the same time complexity. Redundancy is provided at every level of the hierarchy. Hierarchical reconfiguration is performed by replacing the defective cells at the bottom level with the spare cells first and repeating the process at the next higher level if there is not enough redundancy at the current level. Yield analysis is performed to demonstrate the effectiveness of the approach     

Defect-tolerant hierarchical sorting networks for wafer-scaleintegration

A novel hierarchical defect-tolerant sorting network that meets application requirements and area-time complexity constraints is presented. It is very regular in structure and hence easier to reconfigure than any existing sorting network with the same time complexity. Redundancy is provided at every level of the hierarchy. Hierarchical reconfiguration is implemented by replacing the defective cells with spare cells at the lowest level first, and reconfiguration goes to the next higher level if there is not enough redundancy at the current level. These redundant cells can be used for single error correction at run time. Simulations demonstrate that significant yield improvements over other approaches can be achieved     

Network high availability for ethernet services using IP/MPLS networks

Enterprises are increasingly using Ethernet as the foundation for transforming their networks to Internet Protocol. Simultaneously, service providers are deploying Ethernet to exploit the demand for wide-area Ethernet services and as the infrastructure for new residential services such as IPTV. This is due to Ethernet's low cost per bit and ubiquity in local area networks. Recent years have seen the widespread deployment of IP/MPLS networks to address this opportunity. IP/MPLS enables enhanced flexibility over the same converged network for IP and legacy services, avoiding the need to build separate per-service networks. It also adds carrier- grade capabilities such as quality of service, traffic engineering, and resiliency, thereby enabling new multipoint services such as virtual private LAN service. However, using Ethernet for ";always-on"; and other mission-critical services has resulted in new resiliency requirements, in both the access and the network core. Two novel developments address these high expectations by enabling significant improvements in service availability. These are pseudowire redundancy and Ethernet multi-chassis link aggregation. This article reviews the current redundancy mechanisms typically deployed in Ethernet and MPLS networks. We show how additional enhancements are required in both the network core and the access to the Ethernet service. We describe new pseudowire redundancy and MC- LAG mechanisms, showing how they work together to enable end-to-end protection for Ethernet virtual private wire services and VPLS.     

An algebraic approach to network coding

We take a new look at the issue of network capacity. It is shown that network coding is an essential ingredient in achieving the capacity of a network. Building on recent work by Li et al.(see Proc. 2001 IEEE Int. Symp. Information Theory, p.102), who examined the network capacity of multicast networks, we extend the network coding framework to arbitrary networks and robust networking. For networks which are restricted to using linear network codes, we find necessary and sufficient conditions for the feasibility of any given set of connections over a given network. We also consider the problem of network recovery for nonergodic link failures. For the multicast setup we prove that there exist coding strategies that provide maximally robust networks and that do not require adaptation of the network interior to the failure pattern in question. The results are derived for both delay-free networks and networks with delays.     

Neural network optimization for redundancy allocation

System reliability optimization problems such as redundancy allocation are hard to solve exactly. Neural networks offer an alternative computational model for obtaining good approximate solutions for such problems. In this paper we present a neural network for solving the redundancy allocation problem for a n-stage parallel redundant system with separable objective function and constraints. The problem is formulated as a 0–1 integer programming problem and solved using the network. The performance of the network compare favourably with that of the best fit algorithm. The number of iterations taken by the network increases very slowly with increase in number of variables. Hence the network can easily solve large problems.     

Efficient Sensing Topology Management for Spatial Monitoring with Sensor Networks

We focus on exploiting redundancy for sensor networks in the context of spatial interpolation. The network acts as a distributed sampling system, where sensors periodically sample a physical phenomenon of interest, e.g. temperature. Samples are then used to construct a continuous spatial estimate of the phenomenon over time through interpolation. In this regime, the notion of sensing range typically utilized to characterize redundancy in event detection applications is meaningless and sensor selection schemes based on it become unsuitable. Instead, this paper presents pragmatic approaches for exploiting redundancy in such applications. Their underlying characteristic is that no a-priori assumptions need to be made on the statistical properties of the physical phenomenon. These are instead learned by the network after deployment. Our approaches are evaluated through real as well as synthetic sensor network data showing that significant reductions in the number of active sensors are indeed possible.     

Design, analysis, and evaluation of concurrent checking sortingnetworks

In this brief, we propose two new concurrent error-detection (CED) schemes for a class of sorting networks, e.g., odd-even transposition, bitonic, and perfect shuffle sorting networks. A probabilistic method is developed to analyze the fault coverage, and the hardware overhead is evaluated. We first propose a CED scheme by which all errors caused by single faults in a concurrent checking sorting network can be detected. This scheme is the first one available to use significantly less hardware overhead than duplication without compromising throughput. From this scheme, we develop another fault detection scheme which sharply reduces the hardware overhead (using an additional 10%~30% hardware) but still achieves virtually 1001 fault coverage     

邻近信息约束下的随机异构无线传感器网络节点调度算法

针对高密度部署的随机异构传感器网络内部存在的覆盖冗余问题,该文提出一种随机异构无线传感器网络的节点调度算法(NSSH)。在网络原型拓扑的支撑下构建Delaunary三角剖分,规划出节点进行本地化调度的局部工作子集。通过折中与邻近节点的空外接圆半径,完成对感知半径的独立配置;引入几何线、面概念,利用重叠面积和有效约束圆弧完成对灰、黑色节点的分类识别,使得节点仅依赖本地及邻居信息进行半径调整和冗余休眠。仿真结果表明,NSSH能以低复杂度的代价,近似追平贪婪算法的去冗余性能,并表现出了对网络规模、异构跨度和参数配置的低敏感性。     

A novel methodology for robust VBR video transmission in an ATM system

A dynamic FEC (DFEC) scheme for VBR video in ATM networks is proposed. The scheme combines the design of source encoder, error control, and the network. In the design, we will develop a methodology to vary FEC redundancy dynamically. The methodology considers the fluctuations in video source and network utilisation to adjust the FEC redundancy levels. We demonstrate the effectiveness of the proposed scheme by examining its performance with three existing schemes in terms of loss rates, throughput, and quality degradation. Copyright © 2002 John Wiley & Sons, Ltd.     

Adaptive load-balancing in WDM mesh networks with performance guarantees

In nowadays, wavelength-division multiplexing (WDM) networks, on the one hand, increasingly more users expect the network to provide high-priority QoS services demanding no congestion and low latency. On the other hand, it is significantly more difficult for network operators to forecast future traffic demands, as the packet traffic running over WDM networks fluctuates over time for a variety of reasons. Confronted with a rough understanding of traffic patterns as well as the increasing number of time-sensitive applications, most networks today are grossly over-provisioned. Thus, designing cost-effective WDM networks in an uncertain traffic environment, which includes network planning and robust routing, is both an important and a challenging task. In this paper, we explore adaptive load-balancing to investigate the problems of network planning and robust routing for WDM mesh networks under varying traffic matrices. We first propose an efficient heuristic algorithm called Maximizing Network Capability (MNC) to provision congestion-free and cost-effective WDM networks based on load-balancing to deal with traffic uncertainty. Then, a novel traffic grooming algorithm called Adding Direct Traffic (ADT) is proposed to implement robust routing with partial traffic information. Finally, we demonstrate by simulation that MNC consumes less resources than previous methods and performs quite close to the optimal solution, while ADT achieves the desirable performance in delay, jitter (delay variation), and throughput compared with existing robust routing and traffic grooming algorithms.