Unreliable Networks Research Articles

Depth-First Forwarding for Unreliable Networks: Extensions and Applications

This paper introduces extensions and applications of depth-first forwarding (DFF)-a data forwarding mechanism for use in unreliable networks such as sensor networks and Mobile Ad hoc NETworks with limited computational power and storage, low-capacity channels, device mobility, etc. Routing protocols for these networks try to balance conflicting requirements of being reactive to topology and channel variation while also being frugal in resource requirements-but when the underlying topology changes, routing protocols require time to re converge, during which data delivery failure may occur. DFF was developed to alleviate this situation: it reacts rapidly to local data delivery failures and attempts to successfully deliver data while giving a routing protocol time to recover from such a failure. An extension of DFF, denoted as DFF++, is proposed in this paper, in order to optimize the performance of DFF by way of introducing a more efficient search ordering. This paper also studies the applicability of DFF to three major routing protocols for the Internet of Things (IoT), including the Lightweight On-demand Ad hoc Distance-vector Routing Protocol-Next Generation (LOADng), the optimized link state routing protocol version 2 (OLSRv2), and the IPv6 routing protocol for low-power and lossy networks (RPL), and presents the performance of these protocols, with and without DFF, in lossy and unreliable networks.

Grid-based Image Encryption using RSA

years, security of several kinds of images is a major issue in secure data communication over any unreliable network. In this paper, a new technique to secure images by using grid-based encryption and decryption approach with RSA cryptosystem has been devised. This approach has taken original image, performed block transformation followed by grid transformation, then finally a public key cryptosystem is applied pixel-by-pixel to secure image. Experimental images have been taken and performed encryption and decryption to elaborate this technique. Error analysis shows that the technique is robust.

Bayesian framework for bilateral teleoperation systems over unreliable network

SUMMARYIn this paper, we present a novel stochastic framework for network-based bilateral teleoperation systems. A Bayesian approach, which provides robust tracking performance in real-world applications, is proposed to estimate and predict the stochastic variables and compensate for the unreliable network conditions. Combining with a practical approach in transport and application layers of the Internet, this paper demonstrates a high performance and efficient prediction and estimation method for bilateral teleoperation system. Experimental results show that the proposed Bayesian approach estimates and predicts true position and force data over unreliable network conditions, and therefore, improves the performance of overall teleoperation systems.

Modern Messaging for Distributed Sytems

Modern software applications rarely live in isolation and nowadays it is common practice to rely on services or consume information provided by remote entities. In such a distributed architecture, integration is key. Messaging, for more than a decade, is the reference solution to tackle challenges of a distributed nature, such as network unreliability, strong-coupling of producers and consumers and the heterogeneity of applications. Thanks to a strong community and a common effort towards standards and consolidation, message brokers are today the transport layer building blocks in many projects and services, both within the physics community and outside. Moreover, in recent years, a new generation of messaging services has appeared, with a focus on low-latency and high-performance use cases, pushing the boundaries of messaging applications. This paper will present messaging solutions for distributed applications going through an overview of the main concepts, technologies and services.

Data-flow Performance Optimisation on Unreliable Networks: the ATLAS Data-Acquisition Case

The ATLAS detector at CERN records proton-proton collisions delivered by the Large Hadron Collider (LHC). The ATLAS Trigger and Data-Acquisition (TDAQ) system identifies, selects, and stores interesting collision data. These are received from the detector readout electronics at an average rate of 100 kHz. The typical event data size is 1 to 2 MB. Overall, the ATLAS TDAQ system can be seen as a distributed software system executed on a farm of roughly 2000 commodity PCs. The worker nodes are interconnected by an Ethernet network that at the restart of the LHC in 2015 is expected to experience a sustained throughput of several 10 GB/s.A particular type of challenge posed by this system, and by DAQ systems in general, is the inherently burstynature of the data traffic from the readout buffers to the worker nodes. This can cause instantaneous network congestion and therefore performance degradation. The effect is particularly pronounced for unreliable network interconnections, such as Ethernet.In this paper we report on the design of the data-flow software for the 2015-2018 data-taking period of the ATLAS experiment. This software will be responsible for transporting the data across the distributed Data-Acquisition system. We will focus on the strategies employed to manage the network congestion and therefore minimisethe data-collection latency and maximisethe system performance. We will discuss the results of systematic measurements performed on different types of networking hardware. These results highlight the causes of network congestion and the effects on the overall system performance.

Layered multiple description video coding using dual-tree discrete wavelet transform and H.264/AVC

A novel hybrid layered multiple description video coding (HLMDVC) algorithm is proposed to provide a robust and flexible video transmission via unreliable networks, like Internet or the wireless ne...

A Game-Theoretic Genetic Algorithm for the reliable server assignment problem under attacks

We introduce the reliable server assignment problem considering attacks, which seeks to choose the locations of servers on a network in order to maximize the network reliability that results from a worst-case attack on the edges of the network. The problem is formulated on an unreliable network such that edges are subject to fail independently, and attacks increase the probability of failure for the attacked network edges. The reliability is measured by the critical service rate, which equals the probability that at least a fraction α of the nodes in the network are connected to a server. We model this problem as a bi-level optimization problem, with the network designer acting as the leader and the attacker acting as the follower. The problem is very difficult to solve, both because of its bi-level structure and because simply evaluating the critical service rate for a single network configuration and attack is NP-hard. We propose a novel Game-Theoretic Genetic Algorithm (GTGA) that simultaneously maintains two populations, one for each player, which interact through a joint payoff matrix. We benchmark the GTGA against a more straightforward Nested GA (NGA) and find that the GTGA significantly outperforms the NGA in terms of solution quality with nearly identical CPU times. We also introduce an efficient simulation method to estimate the reliability for a given set of servers and integrate this into the GAs. We contribute to the literature on the reliable server assignment problem, as well as introducing a novel algorithmic approach that can be adapted to other bi-level optimization problems.

Distributed parameter estimation in unreliable WSNs: Quantized communication and asynchronous intermittent observation

Motivated by the application of wireless sensor networks, we study a class of distributed learning algorithms for estimating an unknown deterministic parameter. In such networks, each sensor activates in an unreliable network environment which admits new nodes joining and old nodes leaving the network, and can tolerate link failures and noisy interference. Additionally, sensors operate under limited computational, bandwidth and energy resources. In order to overcome these constraints, we propose a novel algorithm to reliably estimate the unknown parameter associated with a linear measurement function based on its noisy samples occasionally made at local sensors. Each local sensor processes its observation, updates its estimate through local information exchange and sends its quantized estimate to its one-hop neighbors. Based on the theory of matrix decomposition and stochastic approximation, we show that the studied algorithm converges almost surely to the unknown parameter with probability one, and the sensor estimate is, in expectation, equal to the unknown parameter. Specifically, we further provide the upper bounds on the mean square error and ∊-convergence time. Finally, we present a numerical example to assess and compare the communication cost with several similar scheme algorithms to achieve a given performance.

TCP TIPS: Transport Protocol for Unreliable Networks with Latency-Sensitive Data

The article describes TCP TIPS, the transport level protocol, which aim is to effi- ciently use the available bandwidth. This protocol implements the proactive methods for congestion avoidance. These methods allow TCP TIPS to yield the required amount of bandwidth to high-priority flows with realtime data and to use this amount, when it becomes available.

A periodic approach for input‐delay problems: Application to network controlled systems affected by polytopic uncertainties

SummaryThis paper deals with robust stability and stabilization of linear discrete‐time systems subject to uncertainties and network constraints. In network control systems, the control loop is closed over a network, which induces additional dynamics to the original control loop such as delays, sampling, and quantization among many others. This paper focuses on networked induced delays due to unreliable network for which packet losses may occur. An equivalent periodic‐like representation of the resulting system is proposed. This allows first to revisit existing results in this framework and second to take model uncertainties into account by analyzing the closed‐loop model by means of a recent method based on robust control for discrete‐time time‐varying systems. Stability analysis and dynamic state‐feedback stabilization are characterized via new conditions, whose conservatism is extensively discussed. Effectiveness of the proposed methodology is illustrated by numerical examples. Copyright © 2015 John Wiley & Sons, Ltd.

An Edge-Turbulence Algorithm for the 2-MRS Problem on Trees with Unreliable Edges

The sum-max 2-most reliable sources (Sum-Max 2-MRS) problem in a given unreliable network is referred to as finding a pair of nodes in the network from which the expected number of reachable nodes is maximized. This problem is #P-hard on general graphs and admits a cubic time algorithm on trees with unreliable edges. In this paper, we revisit the problem on trees and design an edge-turbulence algorithm with a quadratic time and quadratic spaces. Finally, we further develop an edge-turbulence based parallel algorithm with a lower time complexity.

Dynamic Multiple Description Wavelet Based Image Coding Using Enhanced Particle Swarm Optimization

In this paper, dynamic multiple description wavelet based image coding using enhanced particle swarm optimization (EPSO) is proposed for effective multimedia transmission in the dynamically changing network topologies such as mobile ad-hoc networks (MANETs). In wireless networks, multimedia transmission has become a challenging problem because of changing conditions over time such as packet loss rate (PLR), capacity/bandwidth, network and link conditions. The proposed method is used to simultaneously create optimal multiple description coding (MDC) or sub-images based on the dynamically changing capacity/bandwidth of wireless joint/disjoint communication channels/paths. To perform it, PSO is enhanced by adding a position mutation scheme as a generation feature to employ the proposed dynamic cost function to find the optimal solution within in a search space. To create MDs efficiently, three different wavelet transformation methods which are Discrete Wavelet Transform (DWT), Dual Tree-Complex Wavelet Transform (DT-CWT), and Stationary Wavelet Transform (SWT) are investigated. In this manner, a wavelet transform method is first applied to the given input image to create the sub-bands or set of coefficients as a search space, and then EPSO is employed to find optimal results in the search space to generate MDs. The proposed approach produces good quality of descriptions for effective multimedia transmission over dynamically changing and unreliable communication networks, particularly in wireless and ad-hoc networks (MANETs). The results of the proposed method are compared with the state-of-the-art techniques and simulation results demonstrate that using EPSO with DT-CWT provides a significant improvement of optimal and balanced MDC generation with good quality at different bit-rates.

Cross-layer-based reliable robust transmission for emergency messages in high mobility unreliable VANET networks

To achieve active safe driving has become a key trend in intelligent transport systems ITS. However, in the high-mobility unreliable vehicular ad-hoc networks VANETs, the emergency messages or the driving videos are difficult to be sent to the receivers, the platoon leader or the cloud server in time. The reliable end-to-end transmission protocol suffers from extremely unreliable links, high mobility, and hardly providing an accurate congestion window cwnd for transmissions. This paper proposes a Cross-Layer-based reliable robust CL-TCP to forward real-time emergency messages. CL-TCP proposes several TCP states: congestion, loss, unstable, frozen and disconnecting, to control TCP cwnd according to the status of L2 and L3 protocols. The Enhanced AODV EAODV algorithm is proposed to increase path reliability and maximize throughput. The designed cross-layer messages include: CL_EAODV, CL_ICMP_FB, CL_ICMP_DU, etc. Numerical results demonstrate CL-TCP outperforms others in goodput, number of link-breaks, average packet delivery ratio. Furthermore, CL-TCP yields a higher fairness among TCP connections.

Transmission of Vector Mapped Data over the World Wide Web

Within distributed computing environments, access to very large geospatial datasets often suffers from slow or unreliable network connections. To allow users to start working with a partially delivered dataset, progressive transmission methods are a viable solution. While incremental and progressive methods have been applied successfully to the transmission of raster images over the World Wide Web, and, in the form of prototypes, of triangular meshes, the transmission of vector map datasets has lacked a similar attention. This paper introduces a solution to the progressive transmission of vector map data that allows users to apply analytical GIS methods to partially transmitted data sets. The architecture follows a client-server model with multiple map representations at the server side, and a thin client that compiles transmitted increments into a topologically consistent format. This paper describes the concepts, develops an architecture, and discusses implementation concerns.

An Occupancy Based Cyber-Physical System Design for Intelligent Building Automation

Cyber-physical system (CPS) includes the class of Intelligent Building Automation System (IBAS) which increasingly utilizes advanced technologies for long term stability, economy, longevity, and user comfort. However, there are diverse issues associated with wireless interconnection of the sensors, controllers, and power consuming physical end devices. In this paper, a novel architecture of CPS for wireless networked IBAS with priority-based access mechanism is proposed for zones in a large building with dynamically varying occupancy. Priority status of zones based on occupancy is determined using fuzzy inference engine. Nondominated Sorting Genetic Algorithm-II (NSGA-II) is used to solve the optimization problem involving conflicting demands of minimizing total energy consumption and maximizing occupant comfort levels in building. An algorithm is proposed for power scheduling in sensor nodes to reduce their energy consumption. Wi-Fi with Elimination-Yield Nonpreemptive Multiple Access (EY-NPMA) scheme is used for assigning priority among nodes for wireless channel access. Controller design techniques are also proposed for ensuring the stability of the closed loop control of IBAS in the presence of packet dropouts due to unreliable network links.

TCP TIPS: Transport protocol for unreliable networks with latency-sensitive data

The article describes TCP TIPS, the transport layer protocol, which aim is to efficiently use the available bandwidth. This protocol implements the proactive methods for congestion avoidance. These methods allow TCP TIPS to yield the required amount of bandwidth to high-priority flows with realtime data and to use this amount, when it becomes available.

Epidemiological approach for data survivability in unattended wireless sensor networks

Unattended wireless sensor networks (UWSNs) are wireless sensor networks characterized by sporadic sink presence and operation in hostile settings. The absence of the sink for period of time prevents sensor nodes to offload data in real time and offers greatly increased opportunities for attacks resulting in erasure, modification, or disclosure of sensor-collected data. In this paper, we focus on UWSNs where sensor nodes collect and store data locally and try to upload all the information once the sink becomes available. One of the most relevant issues pertaining UWSNs is to guarantee a certain level of information survivability in an unreliable network and even in the presence of a powerful attackers. In this paper, we first introduce an epidemic-domain inspired approach to model the information survivability in UWSN. Next, we derive a fully distributed algorithm that supports these models and give the correctness proofs.

Over networks H ∞ filtering for discrete singular jump systems with interval time-varying delay

This paper deals with the robust H ∞ filtering for discrete singular systems with jump parameters and interval time-varying delay, whose system mode is transmitted through an unreliable network. The class of systems under consideration is more general and covers the singular jump systems with mode-dependent and mode-independent as two special cases, over networks a novel delay-dependent and partially mode-dependent filter is established via using a mode-dependent Lyapunov function and a finite sum inequality based on quadratic terms. The corresponding filter parameters can be obtained by solving a set of linear matrix inequalities without decomposing the original system matrix. The proposed linear robust filter ensuring that the filtering error singular jump system is to be regular, causal, stochastically stable and satisfies H ∞ performance. In addition, two numerical examples are given to illustrate the effectiveness of the proposed approach.

English

In this paper, It is discussed that why Mobile Ad Hoc Networks are unreliable and some other issues with link stability between the nodes. Then their current solutions are suggested. On the behalf of the vulnerable nature of the MANET, these vulnerabilities disturb the development of mobile ad hoc networks. On the base of these vulnerabilities it is proved that mobile ad hoc networks are unreliable& instable Networks. While in the other part, the mechanism to reduce the unreliability & instability of the wireless link between the devices discussed. Ended up by suggesting some ideas and the solutions that makes Mobile Ad hoc network reliable and stable links between the nodes.

A Fuzzy Controller for TCP Improvement over Mobile Networks

The Transmission Control Protocol (TCP) is used for reliable delivery of data over unreliable networks. Practically, most TCP mechanisms have been carefully designed for wired networks. Neglecting the characteristics of wireless environments can lead to TCP implementations with poor performance. In order to use TCP in mobile networks, improvements have been proposed in this paper to enhance TCP algorithm to distinguish between the different types of loss events. In mobile or static wireless environments, losses are not always due to network congestion, as in the case of wired networks. In this paper, a modified algorithm is presented using fuzzy controller to differentiate the loss events (error loss from congestion loss) that intend at adapting TCP to mobile and static wireless environments with better performance. Simulation results were performed using OMNET simulator and have showed that the new proposal has better throughput than other TCP schemes.