Given their nature, many control applications that arise from the integration of Operation Technologies (OT) and Information Technologies (IT) are built on top of highly reliable real-time (RT) Distributed Control Systems (DCSs). Since a DCS is made up of several computing nodes that exchange information through a communication subsystem, to achieve high reliability it is necessary that both this subsystem and the service from the nodes are very reliable. To provide RT highly reliable communications while benefiting from Ethernet’s advantages, Industry and Academia are pushing the Time-Sensitive Networking Ethernet standards (TSN). On the other hand, one of the most used strategies to ensure a highly reliable service from the nodes is to use fault tolerance in the form of active replication. Our general goal is to develop a complete fault-tolerant architecture (addressing faults both in the communication subsystem and in the nodes) for highly reliable real-time DCSs based on TSN. In this paper we show our ongoing work towards an active replication schema for the nodes of this architecture.
Publication type: Conferences
New emerging Distributed Control Systems (DCSs), like Substation Automation Systems (SASs) of Smart Power Grids, raise new requirements on their underlying control networks. To meet these new requirements, both Industry and Academia are promoting the Time-Sensitive Networking (TSN) Ethernet standards. In particular, TSN includes mechanisms to exchange information simultaneously through several paths of practically any spatially redundant network topology. This topological flexibility can offer a better balance between fault tolerance (FT) and redundancy cost (extra number of components) than classical Industrial Ethernets. However, the mentioned TSN mechanisms may also increase the cost in terms of extra latency
and jitter, which could jeopardize real-time communications. In this paper we show our ongoing work to experimentally assess this extra latency and jitter and, thus, characterize the benefits of TSN in terms of balance between FT and cost.
Modern electrical Substation Automation Systems (SAS) are designed following the guidelines defined in the IEC 61850 standard. This standard specifies the necessary information models and communication services for SAS in such a way that they are independent of the implementation. This allows system designers to choose the specific communication technology that best fits their needs. Time-Sensitive Networking (TSN) is arising as one of the most appealing technologies for this purpose. However, it is necessary to map the communication services to TSN, ensuring that the real-time and fault-tolerance requirements of the messages are met. In particular, efficiently mapping the messages of the Generic Object Oriented Substation Events (GOOSE) service is challenging. This is because it exhibits a transmission pattern that does not align with the types of traffic defined in TSN. In this paper we analyze this transmission pattern, identify and characterize its subpatterns, propose the most suitable mapping for each of them and discuss the efficiency gain with respect the typical approaches used to do this mapping.
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This paper addresses the laborious, time-consuming and error-prone process of generating ground truth data to perform instance segmentation of fish in their natural habitat. Our proposal is to use the Segment Anything Model (SAM), which allows zero-shot inference, to automatically build the segmentation masks, significantly reducing the dataset creation time and enhancing scalability to larger datasets. Experimental results using You Only Look Once (YOLO) demonstrate only marginal performance differences between our approach –with segmentation masks created with no human intervention– and a standard training using a fully human-labeled dataset. The results underscore the effectiveness of the automated workflow discussed herein, showcasing substantial reduction in dataset creation time, particularly in demanding underwater scenarios.
This paper explores the advantages of evaluating Progressive Image Encoding (PIE) methods in the context of the specific task for which they will be used. By focusing on a particular task —fish detection in their natural habitat— and a specific PIE algorithm —Progressive Hierarchical Image Encoding (PHIE)—, the paper investigates the performance of You Only Look Once (YOLO) in detecting fish in underwater images using PHIE-encoded images. This is particularly relevant in underwater environments where image transmission is slow. Results provide insights into the advantages and drawbacks of PHIE image encoding and decoding, not from the perspective of general metrics such as reconstructed image quality but from the viewpoint of its impact on a task —fish detection— that depends on the PHIE encoded and decoded images.
Offline scheduling of Scheduled Traffic (ST) in Time-Sensitive Networks (TSN) without taking into account the quality of service of non-ST traffic, e.g., time-sensitive traffic such as Audio-Video Bridging (AVB) traffic, can potentially cause deadline misses for non-ST traffic. In this paper, we report our ongoing work to propose a solution that, regardless of the ST scheduling algorithm being used, can ensure meeting timing requirements for non-ST traffic. To do this, we define a frame called Guard Frame (GF) that will be scheduled together with all ST frames. We show that a proper design for the GFs will leave necessary porosity in the ST schedules to ensure that all non-ST traffic will meet their timing requirements.
Electrical substations are vital for the power grid, and Substation Automation Systems (SASs) have been employed to enhance substation functionality and safety. As the energy landscape evolves, substations face new challenges such as accommodating an increasing number of prosumers. Thus, SASs require a reliable substation communication network (SCN) capable of supporting real-time control and diverse applications. While Ethernet-based SCN technologies have emerged, they often fall short in meeting all requirements, including TCP/IP support, cost-effective fault tolerance, and managing traffic with different real-time demands. Time-Sensitive Networking (TSN) standards have shown promise in addressing these limitations by providing novel mechanisms. In this paper we compare TSN with the Parallel Redundancy Protocol (PRP) demonstrating that TSN offers better functionality and efficiency. In the direction of designing a comprehensive TSN-based architecture for SASs’ Distributed Control Systems (DCSs) we start here by proposing a roadmap for the fault tolerance aspects.