scholarly journals Real-Time Sensor-Actuator Networks

2005 ◽  
Vol 1 (1) ◽  
pp. 17-34 ◽  
Author(s):  
Shivakumar Sastry ◽  
S. S. Iyengar
Keyword(s):  
Operating System ◽  
Real Time ◽  
Homeland Security ◽  
Full Potential ◽  
Resource Constrained ◽  
Time Model ◽  
Distributed Sensor ◽  
Sensor Actuator ◽  
Node Level ◽  
Collaboration And Communication

Emerging technologies offer new paradigms for computation, control, collaboration, and communication. To realize the full potential of these technologies in industry, defense, and homeland security applications, it is necessary to exploit the real-time distributed computing capabilities of sensor-actuator networks. To reliably design and develop such networks, it is necessary to develop deeper insight into the underlying model for real-time computation and the infrastructure at the node level that supports this model. In this paper, we discuss a new node-level operating system and mechanisms necessary to deploy reliable applications. The overriding issue that guides the design of this operating system is quality of service metric called predictability. A sensor-actuator network is a distributed platform for integrated computation and control in real-time environments. The nodes in such a network are distinguished by being resource constrained. The power of the network arises from the interactions between simple nodes. Such a network extends the popular distributed sensor networks in several dimensions. After identifying a real-time model, we develop a notion of predictability for a sensor-actuator network. We discuss how the node-level operating system is designed in the resource-constrained environment. An efficient multithreading mechanism and scheduling strategy are required to ensure that local tasks are executed within jitter bounds and that end-to-end delays do not violate application constraints. Mechanisms to support communication, monitoring, safety, fault tolerance, programming, diagnosability, reconfiguration, composability, interoperability, and security are discussed.

scholarly journals MIROS: A Hybrid Real-Time Energy-Efficient Operating System for the Resource-Constrained Wireless Sensor Nodes

Sensors ◽  
2014 ◽  
Vol 14 (9) ◽  
pp. 17621-17654 ◽  
Author(s):  
Xing Liu ◽  
Kun Hou ◽  
Christophe de Vaulx ◽  
Hongling Shi ◽  
Khalid Gholami
Keyword(s):  
Operating System ◽  
Real Time ◽  
Energy Efficient ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Resource Constrained ◽  
Wireless Sensor Nodes

scholarly journals An Adaptive Scheduler for Real-Time Operating Systems to Extend WSN Nodes Lifetime

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Roberto Rodriguez-Zurrunero ◽  
Ramiro Utrilla ◽  
Elena Romero ◽  
Alvaro Araujo
Keyword(s):  
Operating System ◽  
Real Time ◽  
Operating Systems ◽  
Research Area ◽  
Rechargeable Batteries ◽  
Wireless Sensor ◽  
Portable Devices ◽  
Wireless Devices ◽  
Changing Environments ◽  
Tasks Scheduling

Wireless Sensor Networks (WSNs) are a growing research area as a large of number portable devices are being developed. This fact makes operating systems (OS) useful to homogenize the development of these devices, to reduce design times, and to provide tools for developing complex applications. This work presents an operating system scheduler for resource-constraint wireless devices, which adapts the tasks scheduling in changing environments. The proposed adaptive scheduler allows dynamically delaying the execution of low priority tasks while maintaining real-time capabilities on high priority ones. Therefore, the scheduler is useful in nodes with rechargeable batteries, as it reduces its energy consumption when battery level is low, by delaying the least critical tasks. The adaptive scheduler has been implemented and tested in real nodes, and the results show that the nodes lifetime could be increased up to 70% in some scenarios at the expense of increasing latency of low priority tasks.

scholarly journals Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song
Keyword(s):  
Sensor Networks ◽  
Real Time ◽  
Information Needs ◽  
Localization Algorithm ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Microseismic Events ◽  
The Stability ◽  
Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

scholarly journals Self-Regulating Demand and Supply Equilibrium in Joint Simulation of Travel Demand and a Ride-Pooling Service

2021 ◽  
pp. 036119812199714
Author(s):  
Gabriel Wilkes ◽  
Roman Engelhardt ◽  
Lars Briem ◽  
Florian Dandl ◽  
Peter Vortisch ◽  
...  
Keyword(s):  
Real Time ◽  
Travel Demand ◽  
State Of The Art ◽  
Choice Model ◽  
Mode Choice ◽  
Attractive Alternative ◽  
Full Potential ◽  
Demand Model ◽  
Modeling Framework ◽  
Demand And Supply

This paper presents the coupling of a state-of-the-art ride-pooling fleet simulation package with the mobiTopp travel demand modeling framework. The coupling of both models enables a detailed agent- and activity-based demand model, in which travelers have the option to use ride-pooling based on real-time offers of an optimized ride-pooling operation. On the one hand, this approach allows the application of detailed mode-choice models based on agent-level attributes coming from mobiTopp functionalities. On the other hand, existing state-of-the-art ride-pooling optimization can be applied to utilize the full potential of ride-pooling. The introduced interface allows mode choice based on real-time fleet information and thereby does not require multiple iterations per simulated day to achieve a balance of ride-pooling demand and supply. The introduced methodology is applied to a case study of an example model where in total approximately 70,000 trips are performed. Simulations with a simplified mode-choice model with varying fleet size (0–150 vehicles), fares, and further fleet operators’ settings show that (i) ride-pooling can be a very attractive alternative to existing modes and (ii) the fare model can affect the mode shifts to ride-pooling. Depending on the scenario, the mode share of ride-pooling is between 7.6% and 16.8% and the average distance-weighed occupancy of the ride-pooling fleet varies between 0.75 and 1.17.

scholarly journals Evaluating Latency in Multiprocessing Embedded Systems for the Smart Grid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3322
Author(s):  
Sara Alonso ◽  
Jesús Lázaro ◽  
Jaime Jiménez ◽  
Unai Bidarte ◽  
Leire Muguira
Keyword(s):  
Operating System ◽  
Smart Grid ◽  
Real Time ◽  
Processing System ◽  
The Other ◽  
Programmable Logic ◽  
Detailed Characterization ◽  
Timing Constraint ◽  
Time Part

Smart grid endpoints need to use two environments within a processing system (PS), one with a Linux-type operating system (OS) using the Arm Cortex-A53 cores for management tasks, and the other with a standalone execution or a real-time OS using the Arm Cortex-R5 cores. The Xen hypervisor and the OpenAMP framework allow this, but they may introduce a delay in the system, and some messages in the smart grid need a latency lower than 3 ms. In this paper, the Linux thread latencies are characterized by the Cyclictest tool. It is shown that when Xen hypervisor is used, this scenario is not suitable for the smart grid as it does not meet the 3 ms timing constraint. Then, standalone execution as the real-time part is evaluated, measuring the delay to handle an interrupt created in programmable logic (PL). The standalone application was run in A53 and R5 cores, with Xen hypervisor and OpenAMP framework. These scenarios all met the 3 ms constraint. The main contribution of the present work is the detailed characterization of each real-time execution, in order to facilitate selecting the most suitable one for each application.

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