Presence Of Faulty Components Research Articles

Fault-Tolerant Partition Resolvability in Mesh Related Networks and Applications

Fault-tolerance of a system measures its working capability in the presence of faulty components in the system. The fault-tolerant partition dimension of a network computes the least number of subcomponents of network required to distinctively identify each node in the presence of faults, having promising applications in telecommunication, robot navigation and geographical routing protocols. In this paper, certain triangular mesh networks including, triangular ladder (<i>Tl_s</i>), triangular mesh (<i>T_s</i>), reflection triangular mesh (<i>rl</i>(<i>T_s</i>)), tower triangular mesh (<i>Tr_s</i>) and reflection tower triangular mesh (<i>rl</i>(<i>Tr_s</i>)) networks are discussed for their partition and fault-tolerant partition resolvability. In this regard, it is shown that the partition dimension of these networks is 3, whereas their fault-tolerant partition dimension is 4.

Data-driven fault diagnosis of bogie suspension components with on- board acoustic sensors

This paper proposes a data-driven approach for fault-detection and isolation of bogie suspension components with on-board acoustic sensors. The fault detection technique is based on the acoustic emissions variation due to structural modal coupling changes in the presence of faulty components. A suspensions component failure introduces an imbalance into the system, resulting in dynamics interferences between the motions. These interferences modify the energy introduced into the system as well as its acoustic emissions. The unknown arbitrary track irregularities generate together with a variable train speed a random nonstationary vehicle excitation. Speech recognition techniques were used to generate features that consider this phenomenon. Frequency spectrums were analysed in different operating conditions to design efficient features. The robustness of the methodology was verified with data from two different test measurement campaigns on a test ring, where the influence of the sensor locations for the fault classification process was studied. The proposed methodology achieved good fault classification performance on the investigated use cases, removed dampers and 50% damper degradation on primary and secondary vertical suspension.

Bio-inspired self-aware fault-tolerant routing protocol for network-on-chip architectures using Particle Swarm Optimization

This research paper proposes a bio-inspired self-aware fault-tolerant routing protocol for network-on-chip architecture using particle swarm optimization (PSO), which considers synchronous, asynchronous, and self-organizing communication mechanisms to intelligently load-balance the traffic on the entire network in the presence of faulty components. By way of experimentation and simulation, this study demonstrates that the proposed scheme can converge to a global optimum, minimal routing path in real time, in the presence of network congestion and faulty routers and links. The basic PSO algorithm was improved to implement the proposed routing scheme, named bio-inspired self-aware fault-tolerant routing protocol (BISFTRP). This scheme uses the synchronous, asynchronous, and self-organizing features of PSO to create a global routing table and intelligent adaptation, which gives rise to scalable, real-time, and dynamic routing decisions with high throughput, low latency, and minimum power consumption. A cycle-accurate simulation system to demonstrate the flexibility and efficiency of the proposed scheme is used. Comparison results with state-of-the-art fault-tolerant routing algorithms show that the BISFTRP routing protocol achieves high routing performance without routing oscillations and throughput degradation. Furthermore, the hardware implementation results show that the BISFTRP router achieves an efficient area and power utilization, compared with state-of-the-art routers.

Intra State Recovery System Design for Cloud based Applications

Background/Objectives: Considering the growing demand for cloud services for development and deploying of critical business applications, it is extremely important that cloud provider guarantees a reliable and robust service by providing fault tolerance mechanisms that enable seamless execution of the business transaction execution even in presence of faulty components. The objective of this paper is to propose a collaborative fault tolerant mechanism between cloud provider and cloud client. Methods/Statistical Analysis: The collaborative fault tolerance approach considers collaboration between the cloud provider and the cloud client to develop a comprehensive fault tolerance solution that can be customised to suit to the hosted cloud applications needs.The proposed design is based on usage of Persistent Map based strategy. Findings: The Persistent Map based strategy saves the state information of execution in the form of P-maps. The P-map is a persistent hash map that stores the current state of execution of a given task. In the case of failure, it can be used to restart the process from the last state at which the task failed and resume the application execution from that point as though no failure occurred.The P-map storage is a crucial element to be considered in the design of the system, that requires careful analysis and can have a huge impact on the execution of an application. Application/Improvements: The authors have considered an approach which requires a collaboration between cloud providers and cloud client to design a fault tolerance mechanism that takes into consideration the complex cloud infrastructure as well behaviour and functionality of the application in focus.

Replication: A Technique for Scalability in Cloud Computing

computing is a technology which produces and consumes huge amount of data every day. This makes the cloud to store tons of applications. The demand for these resources is on the rise. Multi cloud environment is used to satisfy these demands. If multiple providers cooperatively work together, the availability of resource can be improved. The replication of data across multiple places in cloud has become an effective solution to achieve good performance in terms of load balancing, response time and availability. Replication of data is a good way to achieve reliability and improve performance in a distributed system. The rising popularity of cloud computing is an alternative to classic information processing systems. This has increased the importance of its correct and continuous operation even in the presence of faulty components. Fault tolerance is a major concern to guarantee availability and reliability of critical services as well as application execution. In order to minimize failure impact on the system and application execution, failures should be anticipated and proactively handled.

IJARCCE - Computer and Communication Engineering

The increasing popularity of Cloud Computing as an attractive alternative to classic information processing systems has increased the importance of its correct and continuous operation even in the presence of faulty components. But fault tolerance is still a crucial issue in SOC. By utilizing VM technology, the performance and fault isolation of cloud resources can be provisioned on demand in a fine grained, multiplexed manner. The design of the DOPS resource allocation method, utilizes the proportional share model. The key idea is to redistribute available resources among running tasks dynamically, where these tasks could use up the maximum capacity of each resource in node. To locate for qualified nodes in the SOC environment, a fully decentralized range query protocol called PG CAN has been tailored for DOPS. Pointer Gossiping is responsible for making sure every node in the system eventually knows important information about every other node’s state including those that are unreachable. The sensitivity analysis conducted on the model, violates certain assumptions that creates more impact on the dynamic optimal resource allocation of multiple attributes due to faulty components. Hence an analysis will be made in a VM environment, aiming to find a node already present in the network and identify a zone that can be split. Thereby, updating the routing tables of nodes neighbouring the newly split zone. During this step, faulty nodes will be identified and re-routing will be done either by merging zones or managing with the neighbour node, all performed dynamically by the SOC system.

English

Cloud computing is upcoming a mainstream feature of information technology. More progressively enterprises deploy their software systems in the cloud environment. The applications in cloud are usually large scale and containing a lot of distributed cloud components. Building cloud applications is highly reliable for challenging and critical research issues. Information processing systems has increased the significance of its correct and continuous operation even in the presence of faulty components. To address this issue, proposes a cloud framework to build fault-tolerant cloud applications. We first propose fault detection algorithms to identify significant components from the huge amount of cloud components. Then, we present an efficient fault-tolerance strategy selection algorithm to determine the most suitable fault-tolerance strategy for each significant component. Software fault tolerance is widely adopted to increase the overall system reliability in critical applications. System reliability can be enhanced by employing functionally equivalent components to tolerate component failures. Fault-tolerance strategies introduced a three well- known techniques are in the following with formulas for calculating the failure probabilities of the fault-tolerant modules. Our work will mainly be driven toward the implementation of the framework to measure the strength of fault tolerance service and to make an in-depth analysis of the cost benefits among all the stakeholders. An algorithm is proposed to automatically determine an efficient fault-tolerance strategy for the significant cloud components. Using real failure traces and model, we evaluate the proposed resource provisioning policies to determine their performance, cost as well as cost efficiency. The experimental results show that by tolerating faults of a small part of the most important components, the reliability of cloud applications can be highly improved.

Fault Tolerance Management in Cloud Computing: A System-Level Perspective

The increasing popularity of Cloud computing as an attractive alternative to classic information processing systems has increased the importance of its correct and continuous operation even in the presence of faulty components. In this paper, we introduce an innovative, system-level, modular perspective on creating and managing fault tolerance in Clouds. We propose a comprehensive high-level approach to shading the implementation details of the fault tolerance techniques to application developers and users by means of a dedicated service layer. In particular, the service layer allows the user to specify and apply the desired level of fault tolerance, and does not require knowledge about the fault tolerance techniques that are available in the envisioned Cloud and their implementations.

An MPSoC-Based QAM Modulation Architecture with Run-Time Load-Balancing

QAM is a widely used multilevel modulation technique, with a variety of applications in data radio communication systems. Most existing implementations of QAM-based systems use high levels of modulation in order to meet the high data rate constraints of emerging applications. This work presents the architecture of a highly parallel QAM modulator, using MPSoC-based design flow and design methodology, which offers multirate modulation. The proposed MPSoC architecture is modular and provides dynamic reconfiguration of the QAM utilizing on-chip interconnection networks, offering high data rates (more than 1 Gbps), even at low modulation levels (16-QAM). Furthermore, the proposed QAM implementation integrates a hardware-based resource allocation algorithm that can provide better throughput and fault tolerance, depending on the on-chip interconnection network congestion and run-time faults. Preliminary results from this work have been published in the Proceedings of the 18th IEEE/IFIP International Conference on VLSI and System-on-Chip (VLSI-SoC 2010). The current version of the work includes a detailed description of the proposed system architecture, extends the results significantly using more test cases, and investigates the impact of various design parameters. Furthermore, this work investigates the use of the hardware resource allocation algorithm as a graceful degradation mechanism, providing simulation results about the performance of the QAM in the presence of faulty components.

Adaptive wormhole routing in tori with faults: A mathematical approach

Fault-tolerance in a communication network is defined as the ability of the network to effectively utilize its redundancy in the presence of faulty components (i.e., nodes or links). New technologies of integration now enable the design of computing systems with hundreds and even thousands of independent processing elements which can cooperate on the solution of the same problem for a corresponding improvement in the execution time. However, as the number of processing units increases, concerns for reliability and continued operation of the system in the presence of failures must be addressed. Adaptive routing algorithms have been frequently suggested as a means of improving communication performance in large-scale massively parallel computers, Multiprocessors System-on-Chip (MP-SoCs), and peer-to-peer communication networks. Before such schemes can be successfully incorporated in networks, it is necessary to have a clear understanding of the factors which affect their performance potential. This paper proposes a novel analytical model to investigate the performance of five prominent adaptive routings in wormhole-switched 2-D tori fortified with an effective scheme suggested by Chalasani and Boppana [S. Chalasani, R.V. Boppana, Adaptive wormhole routing in tori with faults, IEE Proc. Comput. Digit. Tech. 42(6) (1995) 386–394], as an instance of a fault-tolerant method widely used in the literature to achieve high adaptivity and support inter-processor communications in parallel computers. Analytical approximations of the model are confirmed by comparing them with those obtained through simulation experiments.

Performance analysis of fault-tolerant routing algorithm in wormhole-switched interconnections

With nowadays popularity of large-scale parallel computers, Multiprocessors System-on-Chip (MP-SoCs), multicomputers, cluster computers and peer-to-peer communication networks, fault-tolerant routing becomes an important issue in developing these systems. Fault-tolerant routing algorithms in such systems aim at providing continuous operations in the presence of one or more failures by allowing the graceful degradation of system. The Software-Based fault-tolerant routing scheme has been suggested as an efficient routing algorithm to preserve both communication performance and fault-tolerant demands in parallel computer systems. To study network performance, a number of different analytical models for fault-free routing algorithms have been proposed in the past literature. However, there has not been reported any similar analytical model of fault-tolerant routing in the presence of faulty components. This paper presents a new analytical modeling approach for determining the effects of failures in wormhole-switched 2-D tori using the fault-tolerant Software-Based scheme. More specifically, we describe a general model to derive mathematical expressions to investigate the performance behavior of routing algorithms confronting convex (|-shaped, ?-shaped) or concave (U-shaped, +-shaped, T-shaped, H-shaped) faulty regions. The model is validated through comprehensive simulation experiments for different types of failures.

Communication delay analysis of fault-tolerant pipelined circuit switching in torus

Large-scale parallel systems, Multiprocessors System-on-Chip (MP-SoCs), multicomputers, and cluster computers are often composed of hundreds or thousands of components (such as routers, channels and connectors) that collectively possess failure rates higher than what arise in the ordinary systems. One of the most important issues in the design of such systems is the development of the efficient fault-tolerant mechanisms that provide high throughput and low latency in communications to ensure that these systems will keep running in a degraded mode until the faulty components are repaired. Pipelined Circuit Switching (PCS) has been suggested as an efficient switching method for supporting inter-processor communications in networks due to its ability to preserve both communication performance and fault-tolerant demands in such systems. This paper presents a new mathematical model to investigate the effects of failures and capture the mean message latency in torus using PCS in the presence of faulty components. Simulation experiments confirm that the analytical model exhibits a good degree of accuracy under different working conditions.

Reliable broadcasting

Broadcasting is a process of information dissemination in a communications network whereby a message, originated by one member, is transmitted to all members of the network. By adding some redundant calls to the broadcasting scheme, the completion of the broadcast can be guaranteed in the presence of faulty components. We investigate the implications of transmission failures on broadcasting. In particular, we consider broadcasting when the number of transmission failures is bounded by a constant. We determine the time required to guarantee a broadcast in this model. We also study the number of links required in networks which allow reliable broadcasting.

Fault-Tolerant Routing in MIN-Based Supercomputers

We study methods for routing data in supercomputers that use multistage interconnection networks (MINs), in the presence of faulty components in the network. These methods are applicable to multiprocessors such as IBM GF11 and RP3. These methods are based on the concept of dynamic full access (DFA), which refers to the ability of the network to route data from any processor in the system to any other processor in a finite number of passes through the network. We introduce a graph model called the DFA graph of a MIN and show how it can be used to determine the DFA capability of the MIN under a given set of network faults. When the faults in the network satisfy certain special properties, we present algorithms for routing • any arbitrary permutation in a faulty Benes network, and • any Omega permutation in a faulty Omega network. These algorithms are simple and operate in a distributed fashion. These techniques allow a supercomputer to efficiently realize permutations of data needed in a parallel computing environment despite the presence of faults in the network.

Discrete and continuous models for the performance of reconfigurable multistage systems

The authors analyze the performance of multiprocessor systems with a multistage interconnection network in the presence of faulty components. Models for estimating the system performance, as measured by its bandwidth and processing power, are developed for two different modes of operation. In the first mode, the operation of the system is fully synchronized and all processors which require memory access issue their requests simultaneously. In the second, each processor is allowed to issue its request at any time instant. For each of the two modes of operation, two models are presented providing lower and upper estimates for the bandwidth of multistage systems and an upper estimate for their processing power. The operation of 16*16 synchronous and asynchronous reconfigurable systems has been simulated and the bandwidth and processing power have been calculated. >

On gracefully degrading multiprocessors with multistage interconnection networks

The behavior of a multiprocessing system with a multistage interconnection network is studied in the presence of faulty components. Measures for the connectivity and performance of these systems are proposed, including the average number of operational paths, the average number of accessible processors and memories, the average number of fault-free processors (memories) that are connected to an accessible memory (processor), the bandwidth, and the processing power of the system. Based on these measures, a tight upper bound for the maximal fully connected system is suggested. The gracefully degrading system is then compared, through some numerical examples, to a system whose faulty components are repaired upon failure. Based on these comparisons, the anticipated reduction in system performance can be estimated and consequently, appropriate maintenance policies can be determined. >

Fault-Tolerant Multiprocessors with Redundant-Path Interconnection Networks

In this paper, we study fault-tolerant multiprocessor systems employing redundant-path multistage interconnection networks. Such systems permit interprocessor communication in the presence of faulty components in the network. The interconnection network considered is a delta network augmented with an extra switching stage in front. When the first and last stages are fault-free, the extra-stage delta networks continue to provide full access in the presence of all single and many multiple faults in switching elements of the intermediate stages. In this paper, we use graph-theoretic techniques to study the problem of routing permutations in extra-stage delta networks when faults are present in the network. We first formulate the problem of performing an arbitrary permutation on the fault-free network as a vertex-coloring problem and later extend this to networks with noncritical faults. Although the general problem of realizing a permutation in the minimum number of passes is intractable, classes of permutations with some regularity can be routed optimally. To illustrate the idea, we consider the class of BPC (bit permute-complement) permutations: algorithms for performing arbitrary permutations in this class on the extra-stage delta network are given, both for the fault-free network and for a network with noncritical faults.

Increasing the Reliability of Electronic Equipment by the Use of Redundant Circuits

Electronic equipments which employ large numbers of tubes and components are often unreliable because a large number of parts may fail. A means of countering the undesirable effects of increasing equipment complexity is by introducing even more tubes and components as redundant circuitry. A requirement for obtaining the conditions, in which redundancy is helpful is for the causes of failure of parts to be independent. This calls for circuits to be designed so that as parts fail, their failure will not cause others to fail. The equations relating reliability to the number of circuit elements in the redundant and nonredundant cases are derived and applied to examples which show the degree of improvement which can be achieved. It is shown that equipment having hundreds of tubes could be made sufficiently reliable to satisfy most requirements. This greatly increased reliability can be maintained indefinitely by providing maintenance periods during which replacements are made for the parts which have failed while the operation has continued satisfactorily, the faulty condition having been obscured by the redundancy. This latter property of redundant circuit must be considered when establishing maintenance doctrines for equipment using these principles, since operational tests do not usually indicate the presence of faulty components or tubes. Rather, each tube and component must be temporarily disconnected from its redundant counterpart for the purposes of the test.