Topology Fault Research Articles

Unifying flavors of fault tolerance with the ZX calculus

There are several models of quantum computation which exhibit shared fundamental fault-tolerance properties. This article makes commonalities explicit by presenting these different models in a unifying framework based on the ZX calculus. We focus on models of topological fault tolerance – specifically surface codes – including circuit-based, measurement-based and fusion-based quantum computation, as well as the recently introduced model of Floquet codes. We find that all of these models can be viewed as different flavors of the same underlying stabilizer fault-tolerance structure, and sustain this through a set of local equivalence transformations which allow mapping between flavors. We anticipate that this unifying perspective will pave the way to transferring progress among the different views of stabilizer fault-tolerance and help researchers familiar with one model easily understand others.

Introducing a New Method for DPMU in Detecting the Type and Location of the Fault

Introduction: Nowadays, due to the increasing development of distribution networks, their safety and high-reliability performance are of particular importance. One of the most important problems that endanger the security and reliability of these networks is the creation of some faults in them. In case of a fault in the network, identifying its location and type can be of great help in repairing faulty equipment. Also, by detecting the disconnection of one of the equipment or lines, it is possible to prevent accidents in the network. Methods: Phasor Measurement Unit (PMU) has been widely and successfully used as Transmission- Phasor Measurement Unit (T-PMU). The reporting time of PMUs is much shorter than the old Supervisory Control and Data Acquisition (SCADA) systems. They can provide synchronized phasor measurements that can generate voltage phasors of different network nodes. This study aimed to investigate the various applications of phasor measurement units in distribution networks and present a new method for detecting and analyzing the location and type of fault and topology fault of the distribution network using the Internet of Things (IOT) analysis method. Results: To implement this method, it is necessary to measure different parameters of the distribution network before and after the occurrence of a fault, which is used by the DPMU for measurement. The simulation results indicate that for both single-topology and multi-topology faults, the proposed method has higher accuracy and better detection than the remaining common methods and effectively detects single-topology and multi-topology faults in the distribution network. Conclusion: This method can provide a more accurate network topology to estimate the state of the distribution network, which improves the accuracy of the state estimation and is suitable for implementing various advanced functions of the distribution management system.

A Fault-Tolerant Control Method for Unmanned Aerial Vehicle (UAV) Formation with Topological Faults Considered

A fault-tolerant control method for the UAV formation that has topological fault, control surface fault, actuator fault and uncertainty is proposed. Firstly, the formation motion model and the UAV motion model are established. Then based on the topological fault detection method, the topological fault reconstruction and optimization algorithm is proposed to realize the formation topological fault reconstruction and optimization with minimum communication cost and formation reconstruction cost. In designing the backstepping fault-tolerant control method, the actuator's fault identification module and the auxiliary system module are used to estimate and compensate for the faults of the actuator and the control surface respectively so as to realize the stable flight of the UAV formation under the conditions of actuator fault, control surface fault and uncertainty. The simulation results verify the superiority of the fault-tolerant control method for the UAV formation with topological faults.

Fault Tolerant Control of Five-Level Inverter Based on Redundancy Space Vector Optimization and Topology Reconfigruation

Compared with two-level and three-level inverters, five-level inverters have more redundant space vectors to implement flexible control strategy. A fault tolerance method for open circuit fault of power tube in Neutral Point Clamped (NPC) five level inverter is proposed. The open circuit fault of inverter is divided into type I and type II in this paper. Redundant space vector optimization and topological reconfiguration fault tolerance strategies are used for type I and type II failures, respectively. The basic vector of the synthetic reference vector $\text{U}_{\mathrm {ref}}$ is reoptimize according to the redundant vector, and get a new control strategy after the decision. This method enables the inverter to achieve fault-tolerant operation without modifying hardware or adding bridge arms. The output performance of the inverter after fault is guaranteed and the cost of fault tolerance is greatly reduced. The feasibility and effectiveness of the proposed fault-tolerant method are verified through experiments.

Self-Stabilizing Leader Election in Dynamic Networks

Two silent self-stabilizing asynchronous distributed algorithms are given for the leader election problem in a dynamic network with unique IDs. A leader is elected for each connected component of the network. A BFS DAG, rooted at the leader, is constructed in each component. The construction takes O(Diam) rounds, where Diam is the maximum diameter of any component. Both algorithms are self-stabilizing, silent, and work under the unfair daemon, but use one unbounded integer variable. Algorithm DLE selects an arbitrary process to be the leader of each component. Algorithm DLEND (Distributed Leader Election No Dithering) has the incumbency property and the no dithering property. If the configuration is legitimate and a topological fault occurs, each component will elect, if possible, an incumbent to be its leader, i.e., a process which was a leader before the fault. Furthermore, during this computation, no process will change its choice of leader more than once.

A Single-Phase Five-Level Inverter Topology With Switch Fault-Tolerance Capabilities

Low reliability is one of the major concerns of multilevel inverter due to the requirement of a large number of semiconductor devices as compared to two-level inverters. Thus, in this paper, a novel topology of multilevel inverter is proposed that can tolerate both open and short-circuit faults on its switches. The proposed topology also reduces dc sources and capacitors as compared to the conventional and recently proposed fault-tolerant topologies. Two types of solutions are provided in order to make the proposed topology fault tolerant; first provides a partial solution to fault, while the second provides a complete solution to fault. In addition, a novel switching strategy is proposed to reduce the amount of capacitor voltage ripples under normal and postfault conditions. Also, the proposed switching scheme offers an additional advantage of self-voltage balancing of its capacitor voltage both under normal as well as postfault conditions. To validate the proposed concepts, simulation and experimental analysis are carried out and different results are presented to show the viability of the proposed topology under normal operation, during fault and postfault conditions.

A quantitative fault tolerance evaluation model for topology in wireless sensor networks based on the semi-Markov process

Fault tolerance evaluation has gained increasing importance. In this paper, the semi-Markov process is introduced to describe the fault tolerance of topology in wireless sensor networks. Considering that the changes of topology states leaded by node failure and the changes of topology states leaded by responding to node failure, the topology fault-tolerant state transfer model is established firstly. Then a new fault tolerance evaluation index of topology is proposed based on the property of topology providing network services under different states. The numerical result shows that the topological fault tolerance calculated by the evaluation index and its actual value are consistent, which verifies that the proposed evaluation index can reflect the topological fault tolerance accurately. Moreover, the key factor influencing the topological fault tolerance is also obtained from calculating the sensitivity of parameters in the evaluation index.

Fault-tolerant topology in the wireless sensor networks for energy depletion and random failure

Nodes in the wireless sensor networks (WSNs) are prone to failure due to energy depletion and poor environment, which could have a negative impact on the normal operation of the network. In order to solve this problem, in this paper, we build a fault-tolerant topology which can effectively tolerate energy depletion and random failure. Firstly, a comprehensive failure model about energy depletion and random failure is established. Then an improved evolution model is presented to generate a fault-tolerant topology, and the degree distribution of the topology can be adjusted. Finally, the relation between the degree distribution and the topological fault tolerance is analyzed, and the optimal value of evolution model parameter is obtained. Then the target fault-tolerant topology which can effectively tolerate energy depletion and random failure is obtained. The performances of the new fault tolerant topology are verified by simulation experiments. The results show that the new fault tolerant topology effectively prolongs the network lifetime and has strong fault tolerance.

Design and Analysis for Reliability of Wireless Sensor Network

Reliability is an important performance indicator of wireless sensor network, to some application fields, which have high demands in terms of reliability, it is particularly important to ensure reliability of network. At present, the reliability research findings of wireless sensor network are much more at home and abroad, but they mainly improve network reliability from the networks topology, reliable protocol and application layer fault correction and so on, and reliability of network is comprehensive considered from hardware and software aspects is much less. This paper adopts bionic hardware to implement bionic reconfigurable of wireless sensor network nodes, so as to the nodes have able to change their structure and behavior autonomously and dynamically, in the cases of the part hardware are failure, and the nodes can realize bionic self-healing. Secondly, Markov state diagram and probability analysis method are adopted to realize solution of functional model for reliability, establish the relationship between reliability and characteristic parameters for sink nodes, analyze sink nodes reliability model, so as to determine the reasonable parameters of the model and ensure reliability of sink nodes.