Investigation of Industrial Environmental Influences on Clock Sources and their Effect on the Synchronization Accuracy of IEEE 1588

2007 ◽  
Author(s):  
Sebastian Schriegel ◽  
Juergen Jasperneite
Keyword(s):  
Environmental Influences ◽  
Ieee 1588 ◽  
Synchronization Accuracy

scholarly journals Maximum Likelihood Estimation of Clock Skew in IEEE 1588 with Fractional Gaussian Noise

2015 ◽  
Vol 2015 ◽  
pp. 1-24 ◽  
Author(s):  
Chagai Levy ◽  
Monika Pinchas
Keyword(s):  
Maximum Likelihood ◽  
Gaussian Noise ◽  
Likelihood Estimation ◽  
Packet Delay ◽  
Fractional Gaussian Noise ◽  
Clock Skew ◽  
Ieee 1588 ◽  
Accuracy And Precision ◽  
Ethernet Network ◽  
Synchronization Accuracy

To support system-wide synchronization accuracy and precision in the sub-microsecond range without using GPS technique, the precise time protocol (PTP) standard IEEE-1588 v2 is chosen. Recently, a new clock skew estimation technique was proposed for the slave based on a dual slave clock method that assumes that the packet delay variation (PDV) in the Ethernet network is a constant delay. However, papers dealing with the Ethernet network have shown that this PDV is a long range dependency (LRD) process which may be modeled as a fractional Gaussian noise (fGn) with Hurst exponent (H) in the range of0.5<H<1. In this paper, we propose a new clock skew estimator based on the maximum likelihood (ML) technique and derive an approximated expression for the Cramer-Rao lower bound (CRLB) both valid for the case where the PDV is modeled as fGn (0.5<H<1). Simulation results indicate that our new clock skew method outperforms the dual slave clock approach and that the simulated mean square error (MSE) obtained by our new proposed clock skew estimator approaches asymptotically the developed CRLB.

scholarly journals An optimization method of clock synchronization for large-scale regional power network based on IEEE 1588

2021 ◽  
Vol 2108 (1) ◽  
pp. 012063
Author(s):  
Yue Zuo ◽  
Xingcai Wang ◽  
Bo Zhang
Keyword(s):  
Large Scale ◽  
Clock Synchronization ◽  
Optimization Method ◽  
Frequency Deviation ◽  
Power Network ◽  
Regional Power ◽  
Time Service ◽  
Ieee 1588 ◽  
Noise Characteristics ◽  
Synchronization Accuracy

Abstract At present, mobile devices generally use GPS, Beidou and other satellite time service methods to obtain time, but the clock synchronization based on IEEE 1588 protocol still has deviation. To solve this problem, a clock synchronization method is proposed to improve IEEE 1588 protocol. Based on the analysis of IEEE 1588 protocol, the clock deviation and frequency deviation which affect the synchronization accuracy are modeled. The second-order Kalman filtering algorithm is used to recursively deduce the clock deviation and frequency deviation, and the Allan variance is used to verify the noise characteristics and constantly correct the clock deviation. Finally, the improved effect is verified by relevant experiments. The results show that the improved system can improve the synchronization accuracy.

Behavioral Testing of Mice Concerning Anxiety and Depression

2015 ◽  
Vol 223 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Nina Schweinfurth ◽  
Undine E. Lang
Keyword(s):  
Environmental Influences ◽  
Sickness Behavior ◽  
Laboratory Research ◽  
Anxiety And Depression ◽  
Housing Conditions ◽  
Human Beings ◽  
Behavioral Testing ◽  
New Developments ◽  
Animal Trials ◽  
Resilience Factors

Abstract. In the development of new psychiatric drugs and the exploration of their efficacy, behavioral testing in mice has always shown to be an inevitable procedure. By studying the behavior of mice, diverse pathophysiological processes leading to depression, anxiety, and sickness behavior have been revealed. Moreover, laboratory research in animals increased at least the knowledge about the involvement of a multitude of genes in anxiety and depression. However, multiple new possibilities to study human behavior have been developed recently and improved and enable a direct acquisition of human epigenetic, imaging, and neurotransmission data on psychiatric pathologies. In human beings, the high influence of environmental and resilience factors gained scientific importance during the last years as the search for key genes in the development of affective and anxiety disorders has not been successful. However, environmental influences in human beings themselves might be better understood and controllable than in mice, where environmental influences might be as complex and subtle. The increasing possibilities in clinical research and the knowledge about the complexity of environmental influences and interferences in animal trials, which had been underestimated yet, question more and more to what extent findings from laboratory animal research translate to human conditions. However, new developments in behavioral testing of mice involve the animals’ welfare and show that housing conditions of laboratory mice can be markedly improved without affecting the standardization of results.

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