Clock synchronization Research Papers - Academia.edu (original) (raw)

Top Papers
Most Cited Papers
Most Downloaded Papers
Newest Papers
People
- by
- •
- Multidisciplinary, Communication System, Clock synchronization, Earth Rotation
- by Guillermo Rodriguez-navas and +1
- •
- Model Checking, Clock synchronization, Formal Verification, Fault Tolerant

The fundamental role of signal processing techniques was demonstrated
in the context of clock synchronization in WSNs. This
article explains many existing intuitive clock synchronization
protocols and gives some directions to the necessary ingredients
for devising an optimal estimator operating under an unconventional
environment. However, centralized signal processing
techniques can only help solving the problem of node-to-node
synchronization and possible ad hoc extensions to network-wide
synchronization. The next important step is the application of
decentralized signal processing techniques (e.g., distributed estimation
and detection) to the clock synchronization problem, and
this naturally results in desirable distributed clock synchronization
algorithms. Furthermore, distributed signal processing techniques
will reveal the optimal way of information passing, thus
saving unnecessary communication overhead.

- by H. Meyr
- •
- Channel Estimation, Case Study, Clock synchronization, System performance
- by Ragib Hasan
- •
- Data Analysis, Synchronization, Global Positioning System, Security Requirements
- by E. Serpedin
- •
- Wireless Sensor Networks, Synchronization, Energy efficiency, Time Synchronization

Recently, seven single nucleotide polymorphisms (SNPs) of ARNTL, TIM and PER3 genes were found associated with affective temperaments in bipolar disorder patients. This study aimed to test whether a) the same associations appear in a non-clinical sample; b) the SNPs are related to other affective dimensions; c) the SNPs underpin the associations between chronotype and affective temperaments/dimensions. Three hundred thirty-eight university students completed the Temperament Scale of Memphis, Pisa, Paris and San Diego Auto-questionnaire, the Centre for Epidemiological Studies Depression Scale, the Perceived Stress Scale, the General Health Questionnaire, the Seasonal Pattern Assessment Questionnaire and the Composite Scale of Morningness. Seven SNPs of the ARNTL, TIM and PER3 genes were genotyped. According to nominal significance ARNTL rs7107287 was associated with a cyclothymic temperament, depressive and stress symptoms, general mental health and perceived negative impact of seasonality, while TIM rs10876890 was associated with a hyperthymic temperament and the TIM rs2291738 was associated with chronotype. Different SNPs were related to chronotype and affective temperaments/dimensions and therefore they seem to not underpin relationships between chronotype and affective dysfunction, i.e. in the present study eveningness was related to dysthymic, cyclothymic and irritable temperaments, more symptoms of depression, stress, worse mental health and a negative impact of seasonality, while morningness was related to hyperthymic temperament. The SNPs associations need further replication given that they did not achieve Bonferroni criteria of significance accounting for the number of polymorphisms considered and tests conducted.

- by Konrad S Jankowski
- •
- Chronobiology, Genetics, Psychology, Clinical Psychology

Clock discrepancies are troublesome in distributed systems and pose major difficulties. To avoid mistakes, the clocks of separate CPUs must be synced. This is to ensure that communication and resource sharing are as efficient as possible. As a result, the clocks must be constantly monitored and adjusted. Otherwise, the clocks drift apart. Clock skew causes a disparity in the time values of two clocks. Both of these issues must be solved in order to make effective use of distributed system characteristics. In this study, we briefly explored the features of distributed systems and its algorithms.

- by AMEY THAKUR and +1
- •
- Distributed Computing, Computer Networks, Clock synchronization, Clock Synchronization in Distributed Systems
- by Lucia Bello
- •
- Wireless Sensor Networks, Synchronization, Sensor Arrays, Clock synchronization

Precise time synchronization is expected to play a key role in emerging distributed and real-time applications such as the smart grid and Internet of Things (IoT) based applications. The Precision Time Protocol (PTP) is currently viewed as one of the main synchronization solutions over a packet-switched network, which supports microsecond synchronization accuracy. In this paper, we present a PTP simulation model for OMNeT++ INET, which allows to investigate the synchronization accuracy under different network configurations and conditions. To show some illustrative simulation results using the developed module, we investigate on the network load fluctuations and their impacts on the PTP performance by considering a network with class-based quality-of-service (QoS) support. The simulation results show that the network load significantly affects the network delay symmetry, and investigate a new technique called class probing to improve the PTP accuracy and mitigate the load fluctuation effects.

- by Martin Lévesque
- •
- Modeling and Simulation, Synchronization, Smart Grid, Simulation
- by Do Bui
- •
- Distributed Computing, Wireless Sensor Networks, Synchronization, Time Synchronization

CiteSeerX - Document Details (Isaac Councill, Lee Giles): Since the Controller Area Network standard does not provide a clock synchronization service, many different solutions have been proposed to overcome this problem. Evaluation of... more

- by Julian Proenza
- •
- Clock synchronization
- by Aylin Kantarcı
- •
- Resource sharing, Distributed System, Clock synchronization

The pendulum clock was one of the most important metaphors for early modern philosophers. Christiaan Huygens (1629-1695) discovered his pendulum clock in 1656 based on the principle of isochronism discovered by Galileo (1564-1642). This paper aims at exploring the broad historical context of this invention, showing the role of some key figures such as Andreas Colvius (1594-1671), Elia Diodati (1576-1661), Hugo Grotius (1583-1645) and Constantijn Huygens, the father of Christiaan Huygens. Secondly, it suggests - based on this context - that it is hard to believe that Huygens did not know about Galileo's idea to construct a pendulum regulated clock. Finally, this article illustrates how the Dutch philosopher Spinoza (1632-1677) might have been inspired by Huygens' discovery of the synchronization of the pendulum clocks in his views on the agreement between bodies in the universe.

- by Filip A . Buyse
- •
- Philosophy, Early Modern History, Galileo Galilei, Benedict de Spinoza

Clock synchronization is a prerequisite for the realization of emerging applications in various domains such as industrial automation and the intelligent power grid. This paper surveys the standardized protocols and technologies for providing synchronization of devices connected by packet-switched networks. A review of synchronization impairments and the state-of-the-art mechanisms to improve the synchronization accuracy is then presented. Providing microsecond to sub-microsecond synchronization accuracy under the presence of asymmetric delays in a cost-effective manner is a challenging problem, and still an open issue in many application scenarios. Further, security is of significant importance for systems where timing is critical. The security threats and solutions to protect exchanged synchronization messages are also discussed.

- by Martin Lévesque
- •
- Synchronization, Smart Grid, Clock synchronization
- by Enrico Del Re
- •
- Computer Science, Modulation, Satellite Communication, Maximum Likelihood
- by Guillermo Rodriguez-navas
- •
- Clock synchronization
- by Nikolaus Kero
- •
- Digital Divide, Clock synchronization, High performance, Community Networks

An experimental setup is proposed for comparing and analyzing clock synchronization algorithms in distributed system. Clock synchronization is required for transaction processing applications, process control applications etc. This experimental setup generates transmission delays and synchronization errors for processes and the clock synchronization algorithms try to synchronize the clocks in the system under the effect of these barriers. Two centralized clock synchronization algorithms are used for experiment-Cristian's and Berkeley clock synchronization algorithms.

- by Rahul Sehgal
- •
- Clock synchronization
- by L. De Vito
- •
- OPERATING SYSTEM, Computer Network, Quality of Service, Clock synchronization
- by Massimo Pauri and +1
- •
- Mathematical Physics, Quantum Physics, Quantum Gravity, General Relativity

The pendulum clock was one of the most important metaphors for early modern philosophers. Christiaan Huygens (1629-1695) discovered his pendulum clock in 1656 based on the principle of isochronism discovered by Galileo (1564-1642). This paper aims at exploring the broad historical context of this invention, showing the role of some key figures such as Andreas Colvius (1594-1671), Elia Diodati (1576-1661), Hugo Grotius (1583-1645) and Constantijn Huygens, the father of Christiaan Huygens. Secondly, it suggests - based on this context - that it is hard to believe that Huygens did not know about Galileo’s idea to construct a pendulum regulated clock. Finally, this article illustrates how the Dutch philosopher Spinoza (1632-1677) might have been inspired by Huygens’ discovery of the synchronization of the pendulum clocks in his views on the agreement between bodies in the universe.

- by Filip A . Buyse
- •
- Philosophy, Early Modern History, Galileo Galilei, Benedict de Spinoza
- by Ioannis (Yannis) P Androulakis
- •
- Immune response, Systems Biology, Innate immunity, Humans
- by Galina Weinstein
- •
- Clock synchronization

All existing 4-coordinate systems centered on the world-line of an accelerated observer are only locally defined like it happens for Fermi coordinates both in special and general relativity. As a consequence, it is not known how non-inertial observers can build {\it equal-time surfaces} which a) correspond to a conventional observer-dependent definition of synchronization of distant clocks; b) are good Cauchy surfaces for Maxwell equations. Another type of coordinate singularities are those connected to the relativistic rotating coordinate systems (the rotating disk).We show that the use of Hamiltonian methods based on 3+1 splittings of space-time allows to define as many observer-dependent globally defined radar 4-coordinate systems as nice foliations of space-time with space-like hyper-surfaces admissible according to M$\o$ller (for instance only differentially rotating relativistic coordinate system are allowed). All these conventional notions of an {\it instantaneous 3-space} for an arbitrary observer can be empirically defined by introducing generalizations of Einstein 1over2{1\over 2}1over2 convention for clock synchronization in inertial frames. Each admissible 3+1 splitting corresponds to a non-rigid non-inertial frame centered on the observer. When there is a Lagrangian description of an isolated relativistic system, its reformulation as a parametrized Minkowski theory allows to show that all the admissible synchronization conventions are {\it gauge equivalent}, as it also happens in canonical metric and tetrad gravity, where, however, the chrono-geometrical structure of space-time is dynamically determined.

- by David Alba
- •
- Mathematical Physics, Quantum Physics, General Relativity, Clock synchronization

We study the coupling of N charged scalar particles plus the electro-magnetic field to ADM tetrad gravity and its canonical formulation in asymptotically Minkowskian space-times without super-translations. We make the canonical transformation to the York canonical basis, where there is a separation between the {\it inertial} (gauge) variables and the {\it tidal} ones inside the gravitational field and a special role of the Eulerian observers associated to the 3+1 splitting of space-time. The Dirac Hamiltonian is weakly equal to the weak ADM energy. The Hamilton equations in Schwinger time gauges are given explicitly. In the York basis they are naturally divided in four sets: a) the contracted Bianchi identities; b) the equations for the inertial gauge variables; c) the equations for the tidal ones; d) the equations for matter. Finally we give the restriction of the Hamilton equations and of the constraints to the family of {\it non-harmonic 3-orthogonal} gauges, in which the instantaneous Riemannian 3-spaces have a diagonal 3-metric. The non-fixed inertial gauge variable 3K{}^3K3K (the freedom in the clock synchronization convention) gives rise to a negative kinetic term in the weak ADM energy vanishing only in the gauges with 3K=0{}^3K = 03K=0: is it relevant for dark energy and back-reaction? In the second paper there will be the linearization of the theory to obtain Hamiltonian post-Minkowskian gravity with asymptotic Minkowski background, non-flat instantaneous 3-spaces and no post-Newtonian expansion. This will allow to explore the inertial effects induced by the York time 3K{}^3K3K in non-flat 3-spaces and to check how much dark matter can be explained as an inertial aspect of Einstein's general relativity.

- by David Alba
- •
- Dark Matter, Quantum Cosmology, High Energy Physics, Mathematical Sciences
- by Guido Rizzi
- •
- Mathematics, Physics, General Relativity, Foundations of Physics

While Einstein clocks synchronization process is performed, one has a well defined region in which the clocks are synchronized and another one in which the clocks are not yet synchronized. The frontier between them evolves differently from the perspective of observers in relative motion. A discussion is conducted upon direct observation of the phenomenon and Minkowski diagrams.

- by Nilton Penha Silva
- •
- Clock synchronization

This paper investigates the design problem of adaptive controller and synchronizer for the Qi-Chen system (2005), when the system parameters are unknown. First, we build an adaptive controller to stabilize the Qi-Chen chaotic system to its unstable equilibrium at the origin. Then we build an adaptive synchronizer to achieve global chaos synchronization of the identical Qi-Chen chaotic systems with unknown parameters. The results derived for adaptive stabilization and adaptive synchronization for the Qi-Chen chaotic system are established using adaptive control theory and Lyapunov stability theory. Numerical simulations have been shown to demonstrate the effectiveness of the adaptive control and synchronization schemes derived in this paper for the Qi-Chen chaotic system.

This paper derives new results for the global chaos synchronization of identical Sprott L systems (1994), identical Sprott M systems (1994) and non-identical Sprott L and M systems. Active control method has been deployed to achieve the global chaos synchronization of the identical and different Sprott L and M systems. Our synchronization results have been established using Lyapunov stability theory. Numerical plots have been presented to show the effectiveness of the active synchronization results derived in this paper for the Sprott L and M systems.

- by Bo Ai
- •
- Packet Switching, Synchronization, Algorithm, OFDM

In the present paper, a new protocol for authentication and key distribution is proposed. The new protocol has the aim to achieve a comparable performance with the Kerberos protocol and overcome its drawbacks. For authentication of the exchanged messages during authentication and key distribution, the new protocol uses the Message Authentication Codes (MAC) to exchange the Diffie-Hellman components. On the

- by heba aslan
- •
- CMS, Clock synchronization, Diffie-Hellman-DSA, Key Distribution

Design of clock synchronization for networked nodes faces a fundamental trade-off between synchronization accuracy and univer-sality for heterogeneous platforms, because a high synchronization accuracy generally requires platform-dependent hardware-level network packet timestamping. This paper presents TouchSync, a new indoor clock synchronization approach for wearables that achieves millisecond accuracy while preserving universality in that it uses standard system calls only, such as reading system clock, sampling sensors, and sending/receiving network messages. The design of TouchSync is driven by a key finding from our extensive measurements that the skin electric potentials (SEPs) induced by powerline radiation are salient, periodic, and synchronous on a same wearer and even across different wearers. TouchSync integrates the SEP signal into the universal principle of Network Time Protocol and solves an integer ambiguity problem by fusing the ambiguous results in multiple synchronization rounds to conclude an accurate clock offset between two synchronizing wearables. With our shared code, TouchSync can be readily integrated into any wearable applications. Extensive evaluation based on our Arduino and TinyOS implementations shows that TouchSync's synchronization errors are below 3 and 7 milliseconds on the same wearer and between two wearers 10 kilometers apart, respectively.

- by Zhenyu Yan and +1
- •
- Ubiquitous Computing, Wearable Computing, The Internet of Things, Clock synchronization

In the Distributed Systems (DS) the nodes are communicating with each other using message passing. Many real-time applications such as banking systems, reservation systems that are implemented on distributed systems, it is important to execute each transaction/event in an ordered manner. Ordering of events is essential for proper allocation of available resources and mutual allocation. This can be implemented using clock synchronization. The paper presents a comparative study of clock synchronization algorithms in distributed systems. The paper also discusses time protocol such as Network Time Protocol and Simple Network Time Protocol.

AbstractWe study the problem of landmark selection for landmark-based routing in a network of fixed wireless com-munication nodes. We present a distributed landmark selection algorithm that does not rely on global clock synchronization,... more

- by Jie Gao
- •
- Computer Science, Distributed Algorithms, Routing, Wireless Sensor Networks
- by Paolo Bertasi
- •
- Distributed System, Clock synchronization, Mobile Peer-to-Peer Network

The role of convention in various definitions of clock synchronization and simultaneity is investigated. We show that two principal methods of synchronization can be considered: system internal and system external synchronization. Synchronization by the Einstein procedure and by slow clock transport turn out to be equivalent if and only if the time dilatation factor is given by the Einstein result (1−v 2)1/2. An ether theory is constructed that maintains absolute simultaneity and is kinematically equivalent to special relativity.

- by reza mansouri
- •
- Mathematical Physics, Quantum Physics, Special Relativity, Clock synchronization
- by Edgar Nett
- •
- Information Technology, Synchronization, Distributed Systems, Protocols
- by Nikolaus Kero
- •
- Distributed System, Event Detection, Computer Network, Distributed Processing
- by Jorge Falco
- •
- Computer Networks, Wireless Sensor Networks, Synchronization, Time Synchronization

This is the first of a couple of papers in which, by exploiting the capabilities of the Hamiltonian approach to general relativity, we get a number of technical achievements that are instrumental both for a disclosure of \emph{new} results concerning specific issues, and for new insights about \emph{old} foundational problems of the theory. The first paper includes: 1) a critical analysis of the various concepts of symmetry related to the Einstein-Hilbert Lagrangian viewpoint on the one hand, and to the Hamiltonian viewpoint, on the other. This analysis leads, in particular, to a re-interpretation of {\it active} diffeomorphisms as {\it passive and metric-dependent} dynamical symmetries of Einstein's equations, a re-interpretation which enables to disclose the (nearly unknown) connection of a subgroup of them to Hamiltonian gauge transformations {\it on-shell}; 2) a re-visitation of the canonical reduction of the ADM formulation of general relativity, with particular emphasis on the geometro-dynamical effects of the gauge-fixing procedure, which amounts to the definition of a \emph{global (non-inertial) space-time laboratory}. This analysis discloses the peculiar \emph{dynamical nature} that the traditional definition of distant simultaneity and clock-synchronization assume in general relativity, as well as the {\it gauge relatedness} of the "conventions" which generalize the classical Einstein's convention.

- by Massimo Pauri
- •
- Mathematical Physics, Quantum Physics, General Relativity, Clock synchronization
- by Dave Sayers
- •
- Languages and Linguistics, Sociolinguistics, Learning and Teaching, Academic Writing