39 th Annual Precise Time and Time Interval (PTTI) Meeting AN OSCILLATOR MODEL FOR HIGH-PRECISION SYNCHRONIZATION PROTOCOL DISCRETE EVENT SIMULATION
It is well known that a common notion of time in distributed systems can be used to ensure additi... more It is well known that a common notion of time in distributed systems can be used to ensure additional properties such as real-time behavior or the identification of the order of events. As large-scale hardware testbeds for such systems are neither efficient nor easy to manage, discrete event simulations (DES) can be used to model such networks. However, to ensure an exact behavior of such simulations, high precise models of the local clocks are also needed: the driving oscillators have to be modeled in a way that a DES simulation of a free-running node clock shows the same Allan deviation as the simulated counterpart. This paper shows an approach to find a corresponding model for a simulator using white noise and a filter with the same power density spectrum as real-world oscillators.
High precision and robustness in network-based clock synchronization using IEEE 1588
Proceedings of the 2014 IEEE Emerging Technology and Factory Automation (ETFA), 2014
Network-based clock synchronization is an important prerequisite for many application areas and m... more 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 precision clock synchronization. To achieve this goal, a system design facilitating the IEEE 1588 Precision Time Protocol (PTP) is proposed, which supports multiple masters in parallel and provides highly reliable and robust clock synchronization, while at the same time demanding no changes to the network and timing infrastructure. The slave-side robustness can be further enhanced to provide improved monitoring support for IEEE 1588. This makes the solution especially appealing for large-scale networks where retrofitting must be done efficiently and the network infrastructure is not under the control of the end device operator.
Integration aspects of wireless industrial automation
IECON 2011 - 37th Annual Conference of the IEEE Industrial Electronics Society, 2011
... Available: http://www.isa.org/ISA100/; S. Pollin, I. Tan, B. Hodge, C. Chun, and A. Bahai, &q... more ... Available: http://www.isa.org/ISA100/; S. Pollin, I. Tan, B. Hodge, C. Chun, and A. Bahai, "Harmful Coexistence Between 802.15.4 and ... Available: http://www.flexware.at/; L. Wisniewski, H. Trsek, I. Dominguez-Jaimes, A. Nagy, R. Exel, and N. Kerö, "Location-based Handover in ...
It is well known that a common notion of time in distributed systems can be used to ensure additi... more It is well known that a common notion of time in distributed systems can be used to ensure additional properties such as real-time behavior or the identification of the order of events. As large-scale hardware testbeds for such systems are neither efficient nor easy to manage, discrete event simulations (DES) can be used to model such networks. However, to ensure an exact behavior of such simulations, high precise models of the local clocks are also needed: the driving oscillators have to be modeled in a way that a DES simulation of a free-running node clock shows the same Allan deviation as the simulated counterpart. This paper shows an approach to find a corresponding model for a simulator using white noise and a filter with the same power density spectrum as real-world oscillators.
Low complexity room thermal models for energy optimization in industrial buildings
2015 IEEE 20th Conference on Emerging Technologies & Factory Automation (ETFA), 2015
The prime goal in automation systems is to increase productivity while at the same time save prod... more The prime goal in automation systems is to increase productivity while at the same time save production costs. Nevertheless, in recent years there is increasing concern about the ecological footprint of production systems and a growing demand for energy optimization. Heating, ventilating and air conditioning (HVAC) systems in large industrial buildings consume a substantial amount of energy and typically run independently of the actual production processes. Integrating the two systems, however, can be beneficial in terms of overall energy optimization. This paper proposes a modular modelling of the building thermal load with the aim of connecting this model with the typical architecture of Manufacturing Execution Systems (MES). As the building automation system is distributed, the idea is to bind it with a set of generic cells that encapsulate a thermal model of the physical surrounding as well. With this approach the cell thermal load behaviour can be predicted for energy optimization. To allow implementation on the existing embedded devices and controllers with limited computational resources, a reduced complexity model is developed. As the model is to be used for model predictive control (MPC), also the first steps towards the development of the control algorithm are introduced and the benefits compared to traditional approaches are shown.
Distribution of control functionality in energy-aware industrial building environment
2015 IEEE World Conference on Factory Communication Systems (WFCS), 2015
Modern trends in automation require flexible production with an onus on saving energy. Till recen... more Modern trends in automation require flexible production with an onus on saving energy. Till recently, the focus of production systems has been only saving production costs, but the growing concern over environmental impact of such system has led to a partial change in paradigm. The key for the future generation production system is to successfully integrate the manufacturing environment with energy optimisation. This relies on transparent representation of the building from the point of the Manufacturing Execution System (MES) that is not feasible using conventional centralized approaches to building thermal modeling and optimization. This work focuses on distributing the building automation system in a set of generic cells that encapsulate thermal energy models and optimization algorithms to minimize computational resources required for the system implementation on embedded devices. Combined with a notion of the global overview of the energy optimization with functional aggregation and dynamic clustering concepts, the proposed architecture provides a flexible energy saving solution that can be easily integrated in majority of conventional manufacturing systems as well as related factory buildings without compromising production operations.
Efficient thermal modeling for distributed energy management in industrial buildings
2015 Annual IEEE Systems Conference (SysCon) Proceedings, 2015
Heating, ventilation, and air conditioning (HVAC) systems in large industrial or office buildings... more Heating, ventilation, and air conditioning (HVAC) systems in large industrial or office buildings are complex systems with many data points that pose enormous challenges to engineering and control. From an engineering viewpoint, the classical, centralized approach of system design has obvious limitations in flexibility regarding later reconfigurations and layout changes during system operation. Moreover, a centralized control strategy is limited in terms of energy efficiency. Therefore, distributed schemes relying on single room controllers rather than a centralized HVAC controller are desirable. Such a scalable system setup will also facilitate engineering and re-engineering, e.g., by using a scalable function block approach. Accordingly, the actual control strategy has to rely on model-based predictive control implemented in the individual room controllers in a distributed manner. As such controllers are resource-limited devices, the models should be simple and computationally efficient, yet sufficiently accurate to represent the thermal behavior of the room together with its surroundings. This paper presents an analysis of various room models and proposes a minimum-complexity model. Simulation-based comparison with the state of the art demonstrate no significant loss of accuracy while reducing the implementation effort by 47 percent.
Time-based localisation in unsynchronized wireless LAN for industrial automation systems
ETFA2011, 2011
In the recent years, the term wireless factory automation began raising interest. Its probably mo... more In the recent years, the term wireless factory automation began raising interest. Its probably most appreciated feature, mobility, is yet acknowledged as the key for new applications. Nevertheless, this apparent freedom comes with a palette of requirements, whereof one is localisation. Although locating systems have been an extensive research topic for years, industrial systems impose additional constraints, both in terms
The traditional task of a sensor network is data collection and aggregation for further processin... more The traditional task of a sensor network is data collection and aggregation for further processing. In the case of mobile networks this is usually done via wireless technologies. However, with the establishment of mobility another problem occurs: The question of the actual location of the measured data. This paper proposes a localisation scheme for Wireless LAN, where an existing WLAN infrastructure can be used not only for the collection of sensor data but also for the localisation of the data source. In this investigation localisation in sensor networks is done via the Time Difference of Arrival scheme, which has the advantage that the sensor nodes can be left unmodified.
2020 25th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)
With increasing deployment of wireless devices also localization gets a consequential boost in in... more With increasing deployment of wireless devices also localization gets a consequential boost in industrial and other IoT environments. Localization so far in most cases assumes omnidirectional antennas. This paper investigates a generalized Received Signal Strength (RSS) fingerprinting localization algorithm for antennas with arbitrary radiation patterns in order to include IoT devices with directional antennas in localization.Focus is set on the recursive algorithm which improves performance of the traditional fingerprinting methods. First a machine-learning aided analysis of the overlapping reception areas of the antennas is conducted for quickly determining possible initial positions of the nodes to be localized. Then, for reaching higher resolution, different up-scaling techniques and gradient search is applied. In particular, the localization accuracy vs. computational efficiency is investigated which is an important trade-off for many applications.
A Radio-Map clustering Algorithm for RSS based Localization using Directional Antennas
2019 15th IEEE International Workshop on Factory Communication Systems (WFCS), 2019
Position determination of nodes in wireless networks is becoming a prerequisite in industrial env... more Position determination of nodes in wireless networks is becoming a prerequisite in industrial environments to fulfill various application and network needs ranging from device localization to safety or real-time behavior. Received Signal Strength (RSS) based localization techniques have been a research topic for many years, yet suffer from various physical effects. Usage of directed antennas could increase the localization performance and suppress disturbing effects, yet dramatically increase the complexity of localization especially in large scale networks. In this paper we propose a machine-learning aided approach for clustering the RSS map that significantly optimizes the position estimation of nodes in environments with antennas having arbitrary antenna patterns.
Work-in-Progress: Usage of clustering algorithms for analysis of radio maps for localization using directed antennas
2020 16th IEEE International Conference on Factory Communication Systems (WFCS), 2020
Common localization approaches are usually based on omni-directional antennas. There are various ... more Common localization approaches are usually based on omni-directional antennas. There are various algorithmic methods, all of which assume strictly uniform radiation in all directions. However, in general, the output characteristics of these (nominally omnidirectional) antennas are not completely omnidirectional or even highly directional depending on the specific design. This article investigates the use of clustering algorithms to identify different areas of joint signal parameters that can be used for an RSS-based localization method. A set of clustering algorithms is investigated, and their properties to cluster RSS maps for localization applications are compared. In particular, their score for cluster quality and their execution speed relevant for deployment in embedded systems has been evaluated.
Radio map upscaling - adding antennas in an indoor localization scenario
2021 26th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA ), 2021
With technological revolutions like the Internet of Things and Industry 4.0 on the doorstep, loca... more With technological revolutions like the Internet of Things and Industry 4.0 on the doorstep, localization of network nodes is more important than ever. Indoor localization systems mostly work with omnidirectional antennas for simplicity reasons. Using directional antennas has advantages, though, and devices with such antennas will be included in IoT systems someday. In this paper, the focus is on dynamic changes in the configuration of localization systems. Adding an antenna must be handled fast and efficiently. Frequent recalculations of the configuration could be necessary, and limited resources make a reduction of the computational effort desirable. In this work we look at possible methods to cut the computational effort while minimizing the penalty on accuracy. Since accuracy is of utmost importance for indoor localization, there is a fine line which is important to find.
International Journal of Distributed Sensor Networks, 2011
Distributed sensor systems require clock synchronization between all sensor nodes to provide cons... more Distributed sensor systems require clock synchronization between all sensor nodes to provide consistent view of the overall system. Owing the growing size of networks, the evaluation of the synchronization performance becomes difficult, if done by means of experiments. Simulation is another method to tackle this issue. Realistic simulation of synchronization schemes requires accurate modelling of oscillators which are the driving timers generating various events. One way to characterise oscillators is to utilize the Allan variance, which can be used to generate a phenomenological model based on power spectral density. Since discrete event simulation (DES) tools are widely used to model network protocols, models which combine accuracy and performance are needed. This paper presents a model that was optimised for use in DES. To verify that the simulation results sufficiently match measurements, an implementation in OMNeT++ was done. The results show that the behaviour of distributed s...
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Papers by Anetta Nagy