TMR Design of Distributed System for Sequential Faults

Failures are normal rather than exceptional in cloud computing environments, high fault tolerance issue is one of the major obstacles for opening up a new era of high serviceability cloud computing as fault tolerance plays a key role in ensuring cloud serviceability. Fault tolerant service is an essential part of Service Level Objectives (SLOs) in clouds. To achieve high level of cloud serviceability and to meet high level of cloud SLOs, a foolproof fault tolerance strategy is needed. In this paper, the definitions of fault, error, and failure in a cloud are given, and the principles for high fault tolerance objectives are systematically analyzed by referring to the fault tolerance theories suitable for large-scale distributed computing environments. Based on the principles and semantics of cloud fault tolerance, a dynamic adaptive fault tolerance strategy DAFT is put forward. It includes: (i) analyzing the mathematical relationship between different failure rates and two different fault tolerance strategies, which are checkpointing fault tolerance strategy and data replication fault tolerance strategy; (ii) building a dynamic adaptive checkpointing fault tolerance model and a dynamic adaptive replication fault tolerance model by combining the two fault tolerance models together to maximize the serviceability and meet the SLOs; and (iii) evaluating the dynamic adaptive fault tolerance strategy under various conditions in large-scale cloud data centers and consider different system centric parameters, such as fault tolerance degree, fault tolerance overhead, response time, etc. Theoretical as well as experimental results conclusively demonstrate that the dynamic adaptive fault tolerance strategy DAFT has high potential as it provides efficient fault tolerance enhancements, significant cloud serviceability improvement, and great SLOs satisfaction. It efficiently and effectively achieves a trade-off for fault tolerance objectives in cloud computing environments.

Sun, J., 2020. Fault tolerance mechanism of distributed system for marine communication network. In: Gong, D.; Zhang, M., and Liu, R. (eds.), Advances in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 106, pp. 605–608. Coconut Creek (Florida), ISSN 0749-0208.When the communication network fails or the signal is interrupted, the distributed fault-tolerant system can continue to complete the communication task, which is needed to improve the fault-tolerant performance of the distributed system. Therefore, the key technologies of fault tolerance need to be studied, including the distributed fault-tolerant communication network simulation platform, the communication-network information-storage data structure, the communication protocol between communication network nodes, and the fault-tolerant algorithm of distributed communication network system. In the marine environment, the fleet exchanges data through wireless networks to understand the situation of the fleet-detection area, which can share the processing and calculation tasks. However, the marine environment is complex and changeable, which can cause great interference to the wireless signal, such as sea and cloud-rain clutter. These marine environments will cause the network communication signals to be greatly disturbed, which makes the distributed system unable to guarantee the communication interconnection between each node at any time. Therefore, a data-sharing and distributed-system platform needs to be built, which will design a reasonable system fault-tolerance mechanism. Through the fault-tolerance mechanism of the communication network system, the problem of frequent-node exits can be solved. By optimizing the fault-tolerant strategy of distributed architecture, the system's disaster resistance can be improved. In this research, a fault-tolerance mechanism for a distributed system was designed, which is more suitable for node election.

When ASICs are dedicated to highly dependable applications, concurrent checking and/or fault-tolerance capabilities are necessary on chip. In particular, FSMs must be protected against permanent and transient faults. The authors review the main proposals one can fine on this subject in the literature. Then, an approach is proposed to achieve intrinsic fault tolerance. This approach is based on a specific logic synthesis for FSMs described by their state transition graph. >

Describes an approach for enabling the synergistic coordination between two fault-tolerance protocols to simultaneously tolerate software and hardware faults in a distributed computing environment. Specifically, our approach is based on a message-driven confidence-driven (MDCD) protocol that we have devised for tolerating software design faults, and a time-based (TB) checkpointing protocol that was developed by N. Neves and W.K. Fuchs (1996) for tolerating hardware faults. By carrying out algorithm modifications that are conducive to synergistic coordination between volatile-storage and stable-storage checkpoint establishments, we are able to circumvent the potential interference between the MDCD and TB protocols, and to allow them to effectively complement each other to extend a system's fault tolerance capability. Moreover, the protocol coordination approach preserves and enhances the features and advantages of the individual protocols that participate in the coordination, keeping the performance cost low.

The MARUTI operating system is designed to support hard real-time applications on distributed computer systems while providing a fault-tolerant operation. Its design is object oriented, and the communication mechanism allows transparent use of the resources of a distributed system. Fault tolerance is provided through a consistent set of mechanisms that support a number of policies. Most important, MARUTI supports guaranteed-service scheduling, by which jobs that are accepted by the system are guaranteed to meet the time constraints of the computation requests with a specified degree of fault tolerance. As a consequence, MARUTI applications can be executed in a predictable fashion. The development of current hard real-time applications requires that the analyst estimate the resource requirements for all parts of the computation and then makes sure that the resources are available to meet the time constraints, which tends to be a cumbersome process. As a part of the MARUTI system, a set of tools which support the hard real-time applications during various phases of their life cycle has been developed. The present version of MARUTI has been implemented as a prototype running on a Unix platform. Experiences with the development of this prototype are also presented. >

The explosive growth of the Internet demands higher reliability and performance than what the current networking infrastructure can provide. This dissertation explores novel architectures and protocols that provide a methodology for grouping together multiple networking elements, such as routers, gateways, and switches, to create a more reliable and performant distributed networking system. Clustering of networking elements is a novel concept that requires the invention of distributed computing protocols that facilitate efficient and robust support of networking protocols. We introduce the Raincore protocol architecture that achieves these goals by bridging the fields of computer networks and distributed systems. In designing Raincore, we paid special attention to the unique requirements from the networking environment. First, networking clusters need to scale up the networking throughput in addition to the scaling up of computing power. Second, task switching between the different services supported by a networking element has a major negative impact on performance. Third, fast fail-over time is critical for maintaining network connections in the event of failures. We discuss in depth the design of Raincore Group Communication Manager that addresses the forgoing requirements and provides group membership management and reliable multicast transport. It is based on a novel token-ring protocol. We prove that this protocol is formally correct, namely, it satisfies the set of formal specifications that defines the Group Membership problem. The creation of Raincore has already made a substantial impact both at Caltech and the academic community as well as in the industry. The first application is SNOW, a scalable web server cluster that is part of RAIN, a collaborative project between Caltech and JPL/NASA. The second application is RainWall, a commercial solution created by Rainfinity, a Caltech spin-off company, that provides the first fault-tolerant and scalable firewall cluster. These applications exhibit the fast fail-over response, low overhead, and near-linear scalability of the Raincore protocols. In addition, we studied fault-tolerant networking architectures. In particular, we considered efficient constructions of extra-stage fault-tolerant Multistage Interconnection Networks. Multistage Interconnection Networks provide a way to construct a larger switching network using smaller switching elements. We discovered an optimal family of constructions, in the sense that it requires the least number of extra components to tolerate multiple switching element failures. We prove that this is the only family of constructions that has this optimal fault-tolerance property.

A framework has been provided for designing interconnection network topology based on extended folded cube named as Extended Folded Cube with Cross Connection represented as EFCC(k, i). The proposed network topology is hierarchical, recursive and structurally expansive. The network diameter, average distance and constant degree of nodes of the proposed topology has reduced. The predecessors of the proposed network are less reliable and degree of fault tolerance is less. In presence of some faulty nodes and communication links this topology provides better fault tolerance. The different topological properties like degree connectivity, diameter, local and global average distance of the proposed network topology EFCC(k,i) has been discussed. These metrices proves the proposed topology is a better choice for parallel processing environment as compared to its predecessor. This model has the advantage of increasing higher levels of VLSI process. The study proves that Extended Folded Cube with Cross Connection EFCC(k, i) is suitable for VLSI implementation.

Most of the widely used renewable energy sources like PV systems produce DC output and in order to integrate this output with AC grid, an efficient inverter system with fault tolerance is essential. Even for a little period of time, a switch defect in an inverter might have a negative impact on the related essential loads. While considering the several advantages and applications, cascaded multilevel inverter(CHB MLI) can significantly improve system reliability through its fault-tolerant operation due to its switching redundancy. Many multilevel inverters with several control strategies are proposed in literature, but only fewer inverters are with fault tolerant capability. This research suggests a hybrid H-bridge-based CHB MLI architecture that is fault-tolerant. The inverter is capable of operating with rated power under multiple switch open fault conditions. A five-level fault tolerant CHB MLI is simulated and analysed under various fault conditions. Reconfiguration of inverter is possible under input source variations is also possible in this system. The operation of inverter is validated with experimental results. This inverter is suitable for industrial drives, battery energy storage systems and uninterrupted power systems where reliable operation is needed.

Numerous researchers have suggested numerous solutions based on routing and energy to overcome the prevalence of WSN faults in the current literature. Clustering is the most commonly used energy-efficient and fault-tolerant management technique in WSNs, grouping sensors to manage them and perform distributed activities such as resource management. Although clustering methods are most commonly used to reduce energy consumption, they can also achieve various quality-driven goals, such as network fault tolerance capability. As a result of WSN's unpredictable nature, developing fault tolerance mechanisms is essential. Redundancy and diversity methods are commonly used in networks to increase fault tolerance. As a network management challenge, clustering methods should tolerate malfunctioning sensors while maintaining the network's coverage and stability. Sensors are prone to failure due to their operation in hostile environments with limited battery power. The state of the deployed sensor or cluster head (CH) can be active, redundant, or dead/faulty for the same target region of interest (R). The network's overall lifetime and fault tolerance capability can also be extended by using these backup sensors. By putting redundant sensors into sleep mode, can extend the network lifetime without compromising the quality of service. Sensor networks are generally designed to endure far longer than individual sensors. It is commonly performed by putting sensors to sleep. We propose a robust distributed clustered fault tolerance scheduling (RDCFT) approach that efficiently checks the status of the deployed sensor periodically (based on a sweep-line redundancy check algorithm) in WSNs. Simulation results are based on analytical and experimental studies to validate the effectiveness and usefulness of the proposed work.

The increasing complexity and volume of digital payment transactions demand architectural solutions that ensure continuous service availability while maintaining strict security and compliance standards. This article presents a comprehensive framework for implementing event-driven architecture in payment systems, focusing specifically on failover mechanisms and redundancy patterns that enable seamless operation during service disruptions. The article examines how asynchronous event processing and message-driven communication patterns can decouple payment services, creating natural resilience boundaries that prevent cascading failures common in traditional synchronous architectures. Through detailed analysis of retry mechanisms, circuit breaker implementations, and dynamic gateway routing strategies, the article demonstrates how event-driven systems can automatically recover from transient failures while maintaining transaction integrity and audit compliance. The article explores critical implementation considerations, including idempotency handling, eventual consistency management, and distributed transaction coordination through saga patterns, providing practical guidance for organizations transitioning from legacy payment infrastructures. Case studies illustrate real-world applications of the proposed architecture in scenarios ranging from payment authorization retries to multi-region disaster recovery, highlighting both the technical benefits and operational challenges associated with event-driven payment processing. The article addresses essential security and compliance requirements through tokenization strategies, comprehensive audit logging, and real-time fraud detection integration that leverages event streams for immediate risk assessment. Performance evaluation reveals significant improvements in system throughput, fault tolerance, and recovery capabilities compared to traditional architectures, though implementation requires substantial investment in team expertise and monitoring infrastructure. This article contributes to the growing body of knowledge on distributed payment system design by providing a practical blueprint for achieving high availability and fault tolerance through event-driven architectural principles.

One of the advantages of multiphase machine is the capability of fault tolerance. Variety of post-fault control methods based on hysteresis, proportional-integral (PI), proportional resonant (PR) and model predictive controller (MPC) have gradually been developed. Due to simple structure and decoupling of reduced-order matrix, it is used as an alternative to the Clarke matrix in the healthy mode when the fault happens. Although a lot of control methods adopted a reduced-order matrix as the basic derived technology, the performance of controllers is different, and they need to be compared in term of specific applications in fault tolerance. For this propose, the paper deals with the steady-state and dynamic performance of four current control methods, hysteresis control, PI control, PR control and model predictive control in open-circuit fault. The results shows that the PR control method has low torque ripple, copper loss and derating in healthy and post-fault stage, and the MPC control method has low torque ripple in fault stage and fast response capability after applying fault-tolerant methods.

Over the Internet today, computing and communications environments are more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. Peer-to-Peer network overlays provide a good substrate for creating large-scale data sharing, content distribution and application-level multicast applications. We present DistHash, a P2P overlay network designed to share large sets of replicated distributed objects in the context of large-scale highly dynamic infrastructures. The system uses original solutions to achieve optimal message routing in hop-count and throughput, provide an adequate consistency among replicas, as well as provide a fault-tolerant substrate. In this we present result proving that the system is able to scale to a large number of nodes, and it includes the fault tolerance and system orchestration mechanisms, added in order to assess the reliability and availability of the distributed system in an autonomic manner.

Universal middleware bridge (UMB) provides seamless interoperation among heterogeneous home network middleware. There have been high demands for the UMB components (UMB core and adaptors) to have fault- tolerance capabilities. This paper presents a TMO structuring approach together with new implementation techniques for the fault-tolerant TMO-replica structuring scheme called PSTR. PSTR implementations of UMB components provide fault tolerance capabilities essential in realizing high reliability for the UMB facility.

This paper demonstrates that an adaptive computing system (ACS) is good platform for implementing robotic control algorithms. We show that an ACS can be used to provide both good performance and high dependability. An example of an FPGA-implemented dependable control algorithm is presented. The flexibility of ACS is exploited by choosing the best precision for our application. This reduces the amount of required hardware and improves performance. Results obtained from a WILDFORCE emulation platform showed that even using 0.35 /spl mu/m technology, an FPGA-implemented control algorithm has comparable performance with the software-implemented control algorithm in a 0.25 /spl mu/m microprocessor. Different voting schemes are used in conjunction with multi-threading and combinational redundancy to add fault tolerance to the robotic controller. Error-injection experiments demonstrate that robotic control algorithms with fault tolerance techniques are orders of magnitude less vulnerable to faults compared to algorithms without any fault tolerant features.

Multiphase generators in multi-MW wind energy applications can be realized with a variety of possible topologies. Series connection of machine-side converters elevates the dc-link voltage for the same voltage rating of IGBTs, allowing medium voltage generation on the grid-side. On the other hand, parallel connection of machine-side converters provides fault-tolerant capability, enhancing the system reliability. The combination of series and parallel connection of machine-side converters simultaneously elevates the dc-link voltage and provides some fault tolerance to the system. This work discusses the series-parallel topology for six-phase induction generators and analyzes the fault tolerance capability of the topology. Theoretical analysis and simulations confirm that it is possible to obtain additional fault tolerance at the expense of some unbalance on the individual dc-link voltages.