Clock synchronization in distributed multicomputer systems. Part II

2021 ◽  
Author(s):  
I.V. Asharina
Keyword(s):  
Technology Development ◽  
Fault Tolerant ◽  
Clock Synchronization ◽  
Fault Model ◽  
Complex Task ◽  
Space Applications ◽  
Synchronization Process ◽  
Byzantine Faults ◽  
Characteristic Features ◽  
Modern Technologies

The study substantiates the necessity of clock synchronization in distributed multicomputer systems. The basic definitions related to the concept of clock synchronization are given, and methods of clock synchronization are classified. Increasing the lifecycle of failure- and fault-tolerant distributed multicomputer systems for critical application is one of the most urgent problems at the current level of technology development. This is especially true for unattended distributed multicomputer systems for space applications. The second part deals with synchronization in systems with Byzantine faults, and this is a complex task due to the characteristic features of the fault model. The synchronization process in multi-cluster and multi-complex systems is associated with the multitasking of such systems, which makes the synchronization process even more relevant and multi-criteria. The paper considers the modern technologies providing the synchronization process in systems of critical use.

Clock synchronization in distributed multicomputer systems. Part I

2021 ◽  
Author(s):  
I.V. Asharina
Keyword(s):  
Time Synchronization ◽  
Technology Development ◽  
Fault Tolerant ◽  
Clock Synchronization ◽  
Current Level ◽  
Space Applications ◽  
Synchronization Process ◽  
Byzantine Faults ◽  
Modern Technologies ◽  
Clock Module

The study substantiates the necessity of clock synchronization in distributed multicomputer systems. The basic definitions related to the concept of clock synchronization are given, and methods of clock synchronization are classified. Increasing the lifecycle of failure- and fault-tolerant distributed multicomputer systems for critical application is one of the most urgent problems at the current level of technology development. This is especially true for unattended distributed multicomputer systems for space applications. The development of such systems should begin with the construction of models of faults and self-controlled degradation, ensuring, firstly, their failure and fault tolerance and, secondly, maximum survivability, which is possible only if there are means of clock synchronization in such systems. All activities associated with ensuring the synchronization of any distributed multicomputer systems begin with the concept of synchronization of on-board functions, which is based on the generation of on-board time and includes the synchronization of on-board software and equipment that requires time synchronization or information about the course of time. The main elements of this concept are the processor clock module, the onboard software clock, the atomic navigation clock. The first part of the work gives basic definitions, and considers methods and algorithms related to the clock synchronization process. The second part is devoted to synchronization in systems with Byzantine faults and in multi-cluster and multi-complex, i.e. multitask, systems. The modern technologies providing the synchronization process in such systems are considered.

Analysis and Simulation on Clock Resynchronization in Time Triggered Architecture

2014 ◽  
Vol 556-562 ◽  
pp. 4408-4411
Author(s):  
Chun Xu ◽  
Yue Lin ◽  
Ya Nan Gao ◽  
Song Tao Fan
Keyword(s):  
Real Time ◽  
Fault Tolerant ◽  
Clock Synchronization ◽  
Formal Analysis ◽  
Synchronization Process ◽  
Matlab Simulink ◽  
Clock Drift ◽  
Synchronization Algorithm

An improved clock synchronization algorithm for time triggered architecture has been proposed in this paper. A single reference real time is added in the system, so periodically calibration to real time can be achieved. This algorithm is based on the classical Welch-Lynch[1] fault tolerant clock synchronization process. Systematic clock drift problem has been solved by using the algorithm. Formal analysis is presented, and verification is taken on Matlab/Simulink platform. Simulation result has verified the performance of the algorithm, and the clock difference is bounded as expected.

Challenges and Cloud Computing Environments Towards Big Data

2014 ◽  
pp. 203-208
Author(s):  
Kiran Kumar S V N Madupu
Keyword(s):  
Data Mining ◽  
Cloud Computing ◽  
Big Data ◽  
Technology Development ◽  
Computing Environments ◽  
Modern Technologies

Big Data has terrific influence on scientific discoveries and also value development. This paper presents approaches in data mining and modern technologies in Big Data. Difficulties of data mining as well as data mining with big data are discussed. Some technology development of data mining as well as data mining with big data are additionally presented.

scholarly journals Fault Tolerant PLBGSA: Precedence Level Based Genetic Scheduling Algorithm for P2P Grid

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Piyush Chauhan ◽  
Nitin
Keyword(s):  
Genetic Algorithm ◽  
Directed Acyclic Graph ◽  
Fault Tolerant ◽  
Scheduling Algorithm ◽  
Complex Task ◽  
Grid Scheduling ◽  
Complex Tasks ◽  
Small Organizations ◽  
Grid Resources ◽  
Desirable Trait

Due to monetary limitation, small organizations cannot afford high end supercomputers to solve highly complex tasks. P2P (peer to peer) grid computing is being used nowadays to break complex task into subtasks in order to solve them on different grid resources. Workflows are used to represent these complex tasks. Finishing such complex task in a P2P grid requires scheduling subtasks of workflow in an optimized manner. Several factors play their part in scheduling decisions. The genetic algorithm is very useful in scheduling DAG (directed acyclic graph) based task. Benefit of a genetic algorithm is that it takes into consideration multiple criteria while scheduling. In this paper, we have proposed a precedence level based genetic algorithm (PLBGSA), which yields schedules for workflows in a decentralized fashion. PLBGSA is compared with existing genetic algorithm based scheduling techniques. Fault tolerance is a desirable trait of a P2P grid scheduling algorithm due to the untrustworthy nature of grid resources. PLBGSA handles faults efficiently.

scholarly journals STARTUP AS A NEW CONTENT IN ENTREPRENEURSHIP

2020 ◽  
pp. 26-32
Author(s):  
I. Mazur
Keyword(s):  
Global Economy ◽  
New Product ◽  
Entrepreneurial Activity ◽  
Short Term ◽  
New Business ◽  
History Of ◽  
Characteristic Features ◽  
Business Entities ◽  
Theoretical Foundations ◽  
Modern Technologies

The article studies theoretical foundations for the essence of entrepreneurship and entrepreneur; specifics in defining the concept of “entrepreneur” by representatives of economic schools; four stages of formation of the theories of entrepreneurship, where the characteristic features of the entrepreneur that changed under the influence of socio-economic development (external environment) are analyzed. Based on the economic characteristics of changes in the development of macro and micro levels, the emergence of new types of entrepreneurial activity – startups – is justified; a startup is defined as a fast-growing entity of small innovative entrepreneurship with a short-term history of operations, which operates in conditions of uncertainty and aims to create a fundamentally new product to meet the specific needs of consumers. The logic of forming of the concept of entrepreneur-startupper in the structural scheme is substantiated; the characteristic of a startuper as a peculiar combination of transformed traits of an entrepreneur in accordance to the stages of development of the theory of entrepreneurship is given; the characteristic features of the startupper are revealed; the peculiarities of the functioning of startups in Ukraine are analyzed. The characteristic of the special features of the startup entrepreneur is offered; further study of theories of entrepreneurship in accordance to the trends of the global economy under uncertainty, as well as the study of the features of development and functioning of new business entities – startups as a solution for unmet consumer needs and how to use modern technologies to create a new product, are justified.

scholarly journals Planning Fail-Safe Trajectories for Space Robotic Arms

2021 ◽  
Vol 8 ◽  
Author(s):  
Oliver Porges ◽  
Daniel Leidner ◽  
Máximo A. Roa
Keyword(s):  
Degrees Of Freedom ◽  
Fault Tolerant ◽  
Robotic Manipulators ◽  
Task Completion ◽  
Joint Failure ◽  
Space Applications ◽  
Robotic Arms ◽  
Hazardous Environments ◽  
Potential Risks ◽  
Fail Safe

A frequent concern for robot manipulators deployed in dangerous and hazardous environments for humans is the reliability of task executions in the event of a joint failure. A redundant robotic manipulator can be used to mitigate the risk and guarantee a post-failure task completion, which is critical for instance for space applications. This paper describes methods to analyze potential risks due to a joint failure, and introduces tools for fault-tolerant task design and path planning for robotic manipulators. The presented methods are based on off-line precomputed workspace models. The methods are general enough to cope with robots with any type of joint (revolute or prismatic) and any number of degrees of freedom, and might include arbitrarily shaped obstacles in the process, without resorting to simplified models. Application examples illustrate the potential of the approach.

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