Issues of organizing computations in multicomputer systems with the software-controlled failure- and fault-tolerance. Part III

2021 ◽  
Author(s):  
I.V. Asharina
Keyword(s):  
Fault Tolerance ◽  
Control Systems ◽  
Complex Network ◽  
Fault Tolerant ◽  
Communication Channels ◽  
Distributed Objects ◽  
Multiple Faults ◽  
Broadcast Communication ◽  
The Third ◽  
Point To Point

This three-part paper analyzes existing approaches and methods of organizing failure- and fault-tolerant computing in distributed multicomputer systems (DMCS), identifies and provides rationale for a list of issues to be solved. We review the application areas of failure- and fault- tolerant control systems for complex network and distributed objects. The third part proceeds with the study of the problems of organizing failure- and fault-tolerant computing in distributed multicomputer systems (DMCS), carried out in parts I and II of this work, and deals with the issues related to the diagnosis of multiple faults. The paper describes the main differences in ensuring fault tolerance in systems with broadcast communication channels and point-to-point communication channels.

Issues of organizing computations in multicomputersystems with the software-controlled failure- and fault-tolerance. Part 1

2021 ◽  
Author(s):  
I.V. Asharina
Keyword(s):  
Fault Tolerance ◽  
Critical Level ◽  
Fault Tolerant ◽  
Communication Channels ◽  
State Standards ◽  
Modern Concept ◽  
Multiple Faults ◽  
Point To Point ◽  
Definition Of ◽  
Test Diagnostics

This three-part paper analyzes existing approaches and methods of organizing failure- and fault-tolerant computing in distributed multicomputer systems (DMCS), identifies and provides rationale for a list of issues to be solved. We present the concept of fault tolerance proposed by A. Avizienis, explicate its dissimilarity from the modern concept and the reason for its inapplicability with regard to modern distributed multicomputer systems. We justify the necessity to refine the definition of fault tolerance approved by the State Standards, as well as the necessity to specify three input parameters to be taken into account in the DMCS design methods: permitted fault models, permitted multiplicity of faults, permitted fault sequence capabilities. We formulate the questions that must be answered in order to design a truly reliable, fault-tolerant system and consider the application areas of the failure- and fault-tolerant control systems for complex network and distributed objects. System, functional, and test diagnostics serve as the basis for building unattended failure- and fault-tolerant systems. The concept of self-managed degradation (with the DMCS eventually proceeding to a safe shutdown at a critical level of degradation) is a means to increase the DMCS active life. We consider the issues related to the diagnosis of multiple faults and present the main differences in ensuring fault tolerance between systems with broadcast communication channels and systems with point-to-point communication channels. The first part of the work mainly deals with the analysis of existing approaches and methods of organizing failure- and fault-tolerant computing in DMCS and the definition of the concept of fault-tolerance.

Issues of organizing computations in multicomputer systems with the software-controlled failure- and fault-tolerance. Part II

2021 ◽  
Author(s):  
I.V. Asharina
Keyword(s):  
Fault Tolerance ◽  
Control Systems ◽  
Complex Network ◽  
Critical Level ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Distributed Objects ◽  
Active Life ◽  
Fault Tolerant Systems ◽  
Test Diagnostics

This three-part paper analyzes existing approaches and methods of organizing failure- and fault-tolerant computing in distributed multicomputer systems (DMCS), identifies and provides rationale for a list of issues to be solved. We review the application areas of failure- and fault- tolerant control systems for complex network and distributed objects. The second part further investigates the issues of organizing failure- and fault- tolerance in the DMCS. The systemic, functional, and test diagnostics are viewed as the basis for building unattended failure- and fault-tolerant systems. We introduce the concept of self-managed degradation (when the DMCS eventually proceeds to a safe shutdown at a critical level of degradation) as a means to increase the DMCS active life.

scholarly journals Design of a Fault Tolerant Razor Flip Flop Sklansky Adder for Delay Reduction in FIR Filter

2019 ◽  
Vol 8 (9) ◽  
pp. 2647-2651
Keyword(s):  
Fault Tolerance ◽  
High Performance ◽  
Fault Tolerant ◽  
Digital Signal ◽  
Fir Filter ◽  
Delay Reduction ◽  
Flip Flop ◽  
Multiple Faults ◽  
Fault Tolerant System ◽  
Logic Unit

Basically, to reduce the failure rate in the system, we need to introduce the fault tolerant system. Because of multiple faults occurred in the system, the system will increase the area. To employ the adder architecture, different algorithms are used in digital signal processing. By introducing the fault tolerant system, the reliability of the proposed system will increase. So in this paper we introduced the design of fault tolerant razor flip flop using SKLANSKY adder for delay reduction in FIR filter. The razor flip flop will increase the energy efficiency of proposed system. This flip flop will store the information by latching the circuit. The SKLANSKY adder is the part of arithmetic logic unit. In proposed system, all bits are summed and followed to the fault tolerance system,. This fault tolerance system will detect the error and give efficient output. Hence compared to existed system, the proposed system gives high performance and accuracy in terms of delay.

On-Line Fault-Tolerant Fuzzy-Based Path Planning and Obstacles Avoidance Approach for Manipulator Robots

2018 ◽  
Vol 26 (05) ◽  
pp. 809-838 ◽  
Author(s):  
Abderraouf Maoudj ◽  
Abdelfetah Hentout ◽  
Brahim Bouzouia ◽  
Redouane Toumi
Keyword(s):  
Fault Tolerance ◽  
Path Planning ◽  
Fault Tolerant ◽  
Degree Of Freedom ◽  
Planning Approach ◽  
Industrial Manipulators ◽  
On Line ◽  
Point To Point ◽  
Six Degree Of Freedom ◽  
High Degree

Manipulator robots are widely used in many fields to replace humans in complex and risky environments. However, in some particular environments the robot is prone to failure, resulting in decreased performance. In such environments, it is extremely difficult to repair the robot which interrupts the execution process. Therefore, fault tolerance plays an important role in industrial manipulators applications. In this paper, the key problems related to fault-tolerance and path planning of manipulator robots under joints failures are handled within an on-line fault-tolerant fuzzy-logic based path planning approach for high degree-of-freedom robots. This approach provides an alternative to using mathematical models to control such robots, and improves tolerance to certain faults and mechanical failures. The controller consists of two fuzzy units (i) the first unit, Fuzzy_Path_Planner, is responsible of path planning; (ii) the second unit, Fuzzy_Obstacle_Avoidance, is conceived for obstacles avoidance. Moreover, the proposed approach is capable of repelling the manipulator away from both local minima and limit cycle problems. Finally, to validate the proposed approach and show its performances and effectiveness, different tests are carried out on two six degree-of-freedom manipulator robots (ULM and PUMA560 robots), accomplishing point-to-point tasks, with and without considering some joints failures.

scholarly journals Fault tolerance in networked control systems under intermittent observations

2011 ◽  
Vol 21 (4) ◽  
pp. 639-648 ◽  
Author(s):  
Jean-Philippe Georges ◽  
Didier Theilliol ◽  
Vincent Cocquempot ◽  
Jean-Christophe Ponsart ◽  
Christophe Aubrun
Keyword(s):  
Control System ◽  
Fault Tolerance ◽  
Control Systems ◽  
Networked Control Systems ◽  
Fault Tolerant ◽  
Networked Control System ◽  
Networked Control ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Packet Losses

Fault tolerance in networked control systems under intermittent observationsThis paper presents an approach to fault tolerant control based on the sensor masking principle in the case of wireless networked control systems. With wireless transmission, packet losses act as sensor faults. In the presence of such faults, the faulty measurements corrupt directly the behaviour of closed-loop systems. Since the controller aims at cancelling the error between the measurement and its reference input, the real outputs will, in such a networked control system, deviate from the desired value and may drive the system to its physical limitations or even to instability. The proposed method facilitates fault compensation based on an interacting multiple model approach developed in the framework of channel errors or network congestion equivalent to multiple sensors failures. The interacting multiple model method involved in a networked control system provides simultaneously detection and isolation of on-line packet losses, and also performs a suitable state estimation. Based on particular knowledge of packet losses, sensor fault-tolerant controls are obtained by computing a new control law using fault-free estimation of the faulty element to avoid intermittent observations that might develop into failures and to minimize the effects on system performance and safety.

Fault tolerance properties and motion planning of a six-legged robot with multiple faults

Robotica ◽  
2016 ◽  
Vol 35 (6) ◽  
pp. 1397-1414 ◽  
Author(s):  
Hui Du ◽  
Feng Gao
Keyword(s):  
Fault Tolerance ◽  
Motion Planning ◽  
Full Advantage ◽  
Screw Theory ◽  
Fault Tolerant ◽  
Legged Robots ◽  
Legged Robot ◽  
Multiple Faults ◽  
Real Effects ◽  
Nuclear Disaster

SUMMARYThe six-legged robot Octopus is designed for nuclear disaster relief missions. When the robot suffers from failures, its performance can be significantly affected. Thus, fault tolerance is essential for walking and operating in environments inaccessible to humans. The current fault-tolerant gaits for legged robots usually either initially lock the entire broken leg or just abandon the broken leg, but then fail to take full advantage of the normal actuators on the broken leg and add extra constraints. As the number of broken legs increases, the robot will no longer be able to walk using the existing fault-tolerant gaits. To solve this problem, screw theory is used for analyzing the remaining mobility after failure. Based on the analysis, a method of motion planning through fault-tolerant Jacobian matrices, which are linear, is presented. This method can enable the robot to accomplish desired movement using broken legs along with other certain concomitant motions as compensation. Finally, experiments and simulations of multiple faults demonstrate the real effects on the Octopus robot.

Géographie et cartographie fictionnelles dans l’Utopie (1516) de Thomas More

Moreana ◽  
2010 ◽  
Vol 47 (Number 181- (3-4) ◽  
pp. 9-68
Author(s):  
Jean Du Verger
Keyword(s):  
Complex Network ◽  
Narrative Strategies ◽  
Thomas More ◽  
The Third ◽  
Editio Princeps ◽  
Shed Light ◽  
The Way

The philosophical and political aspects of Utopia have often shadowed the geographical and cartographical dimension of More’s work. Thus, I will try to shed light on this aspect of the book in order to lay emphasis on the links fostered between knowledge and space during the Renaissance. I shall try to show how More’s opusculum aureum, which is fraught with cartographical references, reifies what Germain Marc’hadour terms a “fictional archipelago” (“The Catalan World Atlas” (c. 1375) by Abraham Cresques ; Zuane Pizzigano’s portolano chart (1423); Martin Benhaim’s globe (1492); Martin Waldseemüller’s Cosmographiae Introductio (1507); Claudius Ptolemy’s Geographia (1513) ; Benedetto Bordone’s Isolario (1528) ; Diogo Ribeiro’s world map (1529) ; the Grand Insulaire et Pilotage (c.1586) by André Thevet). I will, therefore, uncover the narrative strategies used by Thomas More in a text which lies on a complex network of geographical and cartographical references. Finally, I will examine the way in which the frontispiece of the editio princeps of 1516, as well as the frontispiece of the third edition published by Froben at Basle in 1518, clearly highlight the geographical and cartographical aspect of More’s narrative.

Fault Tolerant Guidance of Under-Actuated Satellite Formation Flying Using Inter-Vehicle Coulomb Force

2019 ◽  
Vol 2 (1) ◽  
pp. 43-52
Author(s):  
Alireza Alikhani ◽  
Safa Dehghan M ◽  
Iman Shafieenejad
Keyword(s):  
Fault Tolerance ◽  
Formation Flying ◽  
Fault Tolerant ◽  
Coulomb Force ◽  
Control Law ◽  
Triangular Form ◽  
Satellite Formation Flying ◽  
Satellite Formation ◽  
Guidance Law ◽  
Tolerance Approach

In this study, satellite formation flying guidance in the presence of under actuation using inter-vehicle Coulomb force is investigated. The Coulomb forces are used to stabilize the formation flying mission. For this purpose, the charge of satellites is determined to create appropriate attraction and repulsion and also, to maintain the distance between satellites. Static Coulomb formation of satellites equations including three satellites in triangular form was developed. Furthermore, the charge value of the Coulomb propulsion system required for such formation was obtained. Considering Under actuation of one of the formation satellites, the fault-tolerance approach is proposed for achieving mission goals. Following this approach, in the first step fault-tolerant guidance law is designed. Accordingly, the obtained results show stationary formation. In the next step, tomaintain the formation shape and dimension, a fault-tolerant control law is designed.

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