HyNTP: An Adaptive Hybrid Network Time Protocol for Clock Synchronization in Heterogeneous Distributed Systems

2020 ◽  
Author(s):  
Marcello Guarro ◽  
Ricardo G. Sanfelice
Keyword(s):  
Distributed Systems ◽  
Clock Synchronization ◽  
Hybrid Network ◽  
Network Time ◽  
Network Time Protocol ◽  
Heterogeneous Distributed Systems

scholarly journals Overview of Time Synchronization for IoT Deployments: Clock Discipline Algorithms and Protocols

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5928
Author(s):  
Hüseyin Yiğitler ◽  
Behnam Badihi ◽  
Riku Jäntti
Keyword(s):  
Time Synchronization ◽  
Clock Synchronization ◽  
Constrained Systems ◽  
Clock Model ◽  
Network Time ◽  
Expected Performance ◽  
The Everyday ◽  
Network Time Protocol ◽  
Synchronization Problems ◽  
Constrained Devices

Internet of Things (IoT) is expected to change the everyday life of its users by enabling data exchanges among pervasive things through the Internet. Such a broad aim, however, puts prohibitive constraints on applications demanding time-synchronized operation for the chronological ordering of information or synchronous execution of some tasks, since in general the networks are formed by entities of widely varying resources. On one hand, the existing contemporary solutions for time synchronization, such as Network Time Protocol, do not easily tailor to resource-constrained devices, and on the other, the available solutions for constrained systems do not extend well to heterogeneous deployments. In this article, the time synchronization problems for IoT deployments for applications requiring a coherent notion of time are studied. Detailed derivations of the clock model and various clock relation models are provided. The clock synchronization methods are also presented for different models, and their expected performance are derived and illustrated. A survey of time synchronization protocols is provided to aid the IoT practitioners to select appropriate components for a deployment. The clock discipline algorithms are presented in a tutorial format, while the time synchronization methods are summarized as a survey. Therefore, this paper is a holistic overview of the available time synchronization methods for IoT deployments.

scholarly journals Twist-n-Sync: Software Clock Synchronization with Microseconds Accuracy Using MEMS-Gyroscopes

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 68
Author(s):  
Marsel Faizullin ◽  
Anastasiia Kornilova ◽  
Azat Akhmetyanov ◽  
Gonzalo Ferrer
Keyword(s):  
Global Positioning System ◽  
Clock Synchronization ◽  
Bundle Adjustment ◽  
High Rate ◽  
Network Time ◽  
Global Positioning ◽  
Mems Gyroscopes ◽  
Network Time Protocol ◽  
Android App ◽  
High Degree

Sensor networks require a high degree of synchronization in order to produce a stream of data useful for further purposes. Examples of time misalignment manifest as undesired artifacts when doing multi-camera bundle-adjustment or global positioning system (GPS) geo-localization for mapping. Network Time Protocol (NTP) variants of clock synchronization can provide accurate results, though present high variance conditioned by the environment and the channel load. We propose a new precise technique for software clock synchronization over a network of rigidly attached devices using gyroscope data. Gyroscope sensors, or IMU, provide a high-rate measurements that can be processed efficiently. We use optimization tools over the correlation signal of IMU data from a network of gyroscope sensors. Our method provides stable microseconds accuracy, regardless of the number of sensors and the conditions of the network. In this paper, we show the performance of the gyroscope software synchronization in a controlled environment, and we evaluate the performance in a sensor network of smartphones by our open-source Android App, Twist-n-Sync, that is publicly available.

scholarly journals Highly Accurate Timestamping for Ethernet-Based Clock Synchronization

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Patrick Loschmidt ◽  
Reinhard Exel ◽  
Georg Gaderer
Keyword(s):  
Clock Synchronization ◽  
Theory And Practice ◽  
Major Influence ◽  
Network Time ◽  
Network Time Protocol ◽  
Precision Time ◽  
Distributed Measurement ◽  
Synchronization Accuracy ◽  
Coordinate Data

It is not only for test and measurement of great importance to synchronize clocks of networked devices to timely coordinate data acquisition. In this context the seek for high accuracy in Ethernet-based clock synchronization has been significantly supported by enhancements to the Network Time Protocol (NTP) and the introduction of the Precision Time Protocol (PTP). The latter was even applied to instrumentation and measurement applications through the introduction of LXI. These protocols are usually implemented in software; however, the synchronization accuracy can only substantially be improved by hardware which supports drawing of precise event timestamps. Especially, the quality of the timestamps for ingress and egress synchronization packets has a major influence on the achievable performance of a distributed measurement or control system. This paper analyzes the influence of jitter sources remaining despite hardware support and proposes enhanced methods for up to now unmatched timestamping accuracy in Ethernet-based synchronization protocols. The methods shown in this paper reach sub-nanosecond accuracy, which is proven in theory and practice.

DAG Reliability Model and Fault-Tolerant Algorithm for Heterogeneous Distributed Systems

2014 ◽  
Vol 36 (10) ◽  
pp. 2019-2032 ◽  
Author(s):  
Guo-Qi XIE ◽  
Ren-Fa LI ◽  
Lin LIU ◽  
Fan YANG
Keyword(s):  
Distributed Systems ◽  
Fault Tolerant ◽  
Reliability Model ◽  
Heterogeneous Distributed Systems

Network time protocol performance evaluation in LAN environment

2013 ◽  
Vol 32 (4) ◽  
pp. 943-945
Author(s):  
Chao-fu CHEN ◽  
Lei WANG
Keyword(s):  
Performance Evaluation ◽  
Network Time ◽  
Protocol Performance ◽  
Network Time Protocol

scholarly journals Security Vulnerability Assessment of Google Home Connection with an Internet of Things Device

Proceedings ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 1
Author(s):  
Hilal Çepik ◽  
Ömer Aydın ◽  
Gökhan Dalkılıç
Keyword(s):  
Internet Of Things ◽  
Vulnerability Assessment ◽  
Smart Home ◽  
Human Life ◽  
Computer Systems ◽  
Security Vulnerability ◽  
Network Time ◽  
Network Time Protocol ◽  
Home Systems

With virtual assistants, both changes and serious conveniences are provided in human life. For this reason, the use of virtual assistants is increasing. The virtual assistant software has started to be produced as separate devices as well as working on phones, tablets, and computer systems. Google Home is one of these devices. Google Home can work integrated with smart home systems and various Internet of Things devices. The security of these systems is an important issue. As a result of attackers taking over these systems, very serious problems may occur. It is very important to take the necessary actions to detect these problems and to take the necessary measures to prevent possible attacks. The purpose of this study is to test whether an attack that attackers can make to these systems via network time protocol will be successful or not. Accordingly, it has been tried to attack the wireless connection established between Google Home and an Internet of Things device over the network time protocol. Attack results have been shared.

Job scheduling in heterogeneous distributed systems

2001 ◽  
Vol 56 (3) ◽  
pp. 203-212 ◽  
Author(s):  
Helen D Karatza
Keyword(s):  
Distributed Systems ◽  
Job Scheduling ◽  
Heterogeneous Distributed Systems
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