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Internet-of-things (IoT) paradigm exploits the Distributed Measurement System (DMS) to execute measurements. Each node of the DMS has computational and communicative capabilities, and can be equipped by sensors and measurement instruments. Therefore, it can be assumed as Smart Object (SO). The availability of mobile SO (MSO) (cars, smartphones, drones) is taken into consideration in the research to...
In order to ensure timing sequence and synchronization performance between different pulses not affected by temperature drift, a method of detecting temperature and compensating temperature drift based on FPGA was proposed, which can ensure data synchronization between different pulses at different temperatures. Because FPGA temperature influenced temperature drift, this method was used to detect...
As wireless sensor networks become more ubiquitous in the world, the need for lightweight, resilient time synchronization protocols is apparent. Wireless nodes' internal clocks are subject to drift over time due to manufacturing imperfections and environmental changes. While various protocols have been introduced that attempt to correct for this drift, they each have their own peculiarities and issues...
In order to take a consistent snapshot of a distributed system, it is necessary to collate and align local logs from each node to construct a pairwise concurrent cut. By leveraging NTP synchronized clocks, and augmenting them with logical clock causality information, Retroscope provides a lightweight solution for taking unplanned retrospective snapshots of past distributed system states. Instead of...
We propose a new sensor MAC protocol, called Bird- MAC, which is highly energy efficient in the applications where sensors periodically report monitoring status with a very low rate, as in structural health monitoring and static environmental monitoring. Two key design ideas of Bird-MAC are: (a) no need of early-wake-up of transmitters and (b) taking the right balance between synchronization and coordination...
We present the design, development, and deployment of an inexpensive, power-efficient, clustered, and scalable wireless sensor network (WSN) testbed. The testbed operates in a harsh environment in which neither GPS nor Internet connectivity are available. We use this testbed to collect real-time data during football games and other major events at Bobby Dodd stadium at Georgia Tech. The sensing devices...
Industrial communication is on its way from field-bus to Ethernet. In an industry 4.0 scenario various applications and branches in automated manufacturing, process industry and intra logistics are affected. Here, Ethernet communication will not be limited to the communication between controllers and devices such as programmable logic controllers (PLC) and sensors and actors, but will also be applied...
Clock synchronization is one of the most essential assets for distributed real-time systems, as sensing, control and actuation require synchronized communication to meet real-time deadlines. We propose a distributed monitoring method to detect if an adversary is interfering with the clock synchronization protocol. The monitor uses certain network indicators and a set of rules to decide about switching...
Time synchronization (TS) represents an important necessity for many industries in fields such as communications, manufacturing, and power systems related to electrical networks, microgrids, and renewable energies, among others, because it can ensure that cooperating processes or systems can interoperate correctly; further, the scheduling of specific tasks through a timestamp can be done. Among different...
Networks are currently essential for computing: It is therefore essential to guarantee the quality of network links in order to ensure a proper operation of computing systems. However, a widespread deployment of network monitoring devices might not be economically feasible. In this paper, we propose the use of Programmable System-on-Chip FPGAs (PSoCs) for enabling a comprehensive testing of networks...
Deploying and designing a system for object tracking in hostile, inaccessible environments is a challenging task. One of the ways of doing it is by using a global positioning system (GPS). However, systems based on GPS consume larger amount of power and may fail in covered regions. Moreover changing batteries frequently is also a problem. In this paper we have discussed the design and implementation...
DEMETRA aims to be a prototype of an European time dissemination service, based on the timing signal of the European Galileo system, adding particular features like - among the others - certification, calibration, or integrity, that could be of interest to a wide range of users belonging to different sectors as traffic control, energy distribution, finance, telecommunication, and scientific institutions...
For structural health monitoring (SHM), mode shape calculation is an important task that needs to be performed accurately and reliably. The use of wireless sensor networks (WSNs) for SHM is a very effective and a promising solution. However, WSNs experience synchronization errors among the sensor nodes, which can affect the accuracy of the mode shape calculation. In this paper, we study the impact...
This paper describes research into improving IEEE 1588 synchronization accuracy when using 1000BASE-T, Gigabit Ethernet over copper wiring. It describes the possible sources of error in such a system, such as path asymmetries and non-deterministic delays, and proposed solutions for them. The methods described improve synchronization accuracy by enhancing the accuracy of timestamps of both ingress...
Electricity companies will only allow customers to inject power into the grid network if the customer's system is in synch with both frequency and phase as the grid itself. This is normally achieved using a specialised machine sold by the energy provider. It may be possible to achieve this via low cost, low power nodes such as a Raspberry Pi, to synchronize frequency and phase as well as voltage and...
Verification of Gigabit Ethernet MAC (Media Access Control) by using the most advanced verification methodology i.e. UVM (Universal Verification Methodology) has been presented in this paper. The main function of MAC is to forward Ethernet frames to PHY through XGMII (10 Gigabit Media Independent Interface) and to receive the frames from PHY to MAC through the same interface. Verification of IP provides...
Network-based clock synchronization is an important prerequisite for many application areas and more and more required for the factory floor for network arbitration, control, and monitoring. Limitations of existing clock synchronization protocols are that they either support high redundancy and robustness or high precision. This paper presents an approach to integrate slave-side robustness into high...
In current cloud systems, services run across multiple geographically distributed clusters and continuously generate resource usage data due to constant resource consumption. In the context of accounting, resource usage data generated from each cluster during service runtime must be collected and aggregated into a single cloud-wide record so that a single bill can be created. This paper presents a...
The recently-standardized Precision Time Protocol v2 (PTPv2) aims at achieving sub-microsecond-level synchronization between network clocks. In this work, we make the case for an alternative use of it: Adopting a learning approach, we observe its delay behavior during the protocol message exchange, derive models of its dependence on network load and build a real-time load estimation service. Then,...
During the last three years, the NTP servers hosted by the largest Telecommunications and Internet Service Provider in Sweden have been monitored and logged with traceability to UTC(SP), including an estimated uncertainty calculated from the measurements, stratum-level, and synchronization source. The surveillance is ongoing and provides updated information on NTP-synchronization status and network...
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