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Author

Jose Araujo

Other affiliations: Royal Institute of Technology
Bio: Jose Araujo is an academic researcher from Ericsson. The author has contributed to research in topics: Wireless network & Wireless sensor network. The author has an hindex of 14, co-authored 49 publications receiving 729 citations. Previous affiliations of Jose Araujo include Royal Institute of Technology.

Papers
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Journal ArticleDOI
TL;DR: This paper considers three recently proposed aperiodic control algorithms which have the potential to address the wide deployment of wireless sensor and actuator networks in cyber-physical systems and shows how these controllers can be implemented over the IEEE 802.15.4 standard.
Abstract: Wide deployment of wireless sensor and actuator networks in cyber-physical systems requires systematic design tools to enable dynamic tradeoff of network resources and control performance. In this paper, we consider three recently proposed aperiodic control algorithms which have the potential to address this problem. By showing how these controllers can be implemented over the IEEE 802.15.4 standard, a practical wireless control system architecture with guaranteed closed-loop performance is detailed. Event-based predictive and hybrid sensor and actuator communication schemes are compared with respect to their capabilities and implementation complexity. A two double-tank laboratory experimental setup, mimicking some typical industrial process control loops, is used to demonstrate the applicability of the proposed approach. Experimental results show how the sensor communication adapts to the changing demands of the control loops and the network resources, allowing for lower energy consumption and efficient bandwidth utilization.

154 citations

Journal ArticleDOI
08 Jan 2019
TL;DR: The aspects of the framework such as its created TI architecture, including the elements, functions, interfaces, and other considerations therein, as well as the novel aspects and differentiating factors compared with, e.g., 5G Ultra-Reliable Low-Latency Communication.
Abstract: The IEEE “Tactile Internet” (TI) Standards working group (WG), designated the numbering IEEE 1918.1, undertakes pioneering work on the development of standards for the TI. This paper describes the WG, its intentions, and its developing baseline standard and the associated reasoning behind that and touches on a further standard already initiated under its scope: IEEE 1918.1.1 on “Haptic Codecs for the TI.” IEEE 1918.1 and its baseline standard aim to set the framework and act as the foundations for the TI, thereby also serving as a basis for further standards developed on TI within the WG. This paper discusses the aspects of the framework such as its created TI architecture, including the elements, functions, interfaces, and other considerations therein, as well as the novel aspects and differentiating factors compared with, e.g., 5G Ultra-Reliable Low-Latency Communication, where it is noted that the TI will likely operate as an overlay on other networks or combinations of networks. Key foundations of the WG and its baseline standard are also highlighted, including the intended use cases and associated requirements that the standard must serve, and the TI’s fundamental definition and assumptions as understood by the WG, among other aspects.

113 citations

Journal ArticleDOI
01 Feb 2019
TL;DR: The tactile internet will enable a new range of capabilities to enable immersive remote operations and interactions with a physical world, as it will provide necessary capabilities for the demanding communication needs in terms of reliability and low latency, for operators or teleoperated systems that are connected wirelessly.
Abstract: The tactile internet will enable a new range of capabilities to enable immersive remote operations and interactions with a physical world. Tactile internet use cases span over many fields, from remote operation of industrial applications in, e.g., hazardous environments, via remote-controlled driving in a fully automated intelligent transport system, to remote surgery where the unique expert skills can be delivered to different locations in the world. Fifth-generation (5G) communication will play a fundamental part in this tactile internet vision, as it will provide necessary capabilities for the demanding communication needs in terms of reliability and low latency, for operators or teleoperated systems that are connected wirelessly. This paper provides an overview of tactile internet services and haptic interactions and communication. The 5G functionality for ultrareliable and low-latency services is described in depth and it is shown how 5G new radio (NR) and the evolved long-term evolution (LTE) radio interface can achieve guaranteed low-latency wireless transmission. The costs for providing reliable and low-latency wireless transmission in terms of reduced spectral efficiency and coverage are discussed. The 5G system architecture with a software-based network design based on a distributed cloud platform is presented. It is shown how the 5G network is configured for tactile internet services via multidomain orchestration.

95 citations

Proceedings ArticleDOI
11 Apr 2011
TL;DR: An analytical model of the packet loss probability and delay of a IEEE 802.15.4 network is presented and it is shown that the optimal traffic load is similar when the communication throughput or control cost are optimized.
Abstract: A framework for the joint design of wireless network and controllers is proposed. Multiple control systems are considered where the sensor measurements are transmitted to the controller over the IEEE 802.15.4 protocol. The essential issues of wireless networked control systems (NCSs) are investigated to provide an abstraction of the wireless network for a co-design approach. We first present an analytical model of the packet loss probability and delay of a IEEE 802.15.4 network. Through optimal control techniques we derive the control cost as a function of the packet loss probability and delay. Simulation results show the feasible control performance. It is shown that the optimal traffic load is similar when the communication throughput or control cost are optimized. The co-design approach is based on a constrained optimization problem, for which the objective function is the energy consumption of the network and the constraints are the packet loss probability and delay, which are derived from the desired control cost. The co-design is illustrated through a numerical example.

94 citations

Journal ArticleDOI
TL;DR: This paper examines distributed event-triggered estimation over wireless sensor networks and finds that in such systems an efficient utilization of the wireless communications must be performed since energy cons of such systems are high.

57 citations


Cited by
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Proceedings ArticleDOI
01 Dec 2012
TL;DR: An introduction to event- and self-triggered control systems where sensing and actuation is performed when needed and how these control strategies can be implemented using existing wireless communication technology is shown.
Abstract: Recent developments in computer and communication technologies have led to a new type of large-scale resource-constrained wireless embedded control systems. It is desirable in these systems to limit the sensor and control computation and/or communication to instances when the system needs attention. However, classical sampled-data control is based on performing sensing and actuation periodically rather than when the system needs attention. This paper provides an introduction to event- and self-triggered control systems where sensing and actuation is performed when needed. Event-triggered control is reactive and generates sensor sampling and control actuation when, for instance, the plant state deviates more than a certain threshold from a desired value. Self-triggered control, on the other hand, is proactive and computes the next sampling or actuation instance ahead of time. The basics of these control strategies are introduced together with a discussion on the differences between state feedback and output feedback for event-triggered control. It is also shown how event- and self-triggered control can be implemented using existing wireless communication technology. Some applications to wireless control in process industry are discussed as well.

1,642 citations

Journal ArticleDOI
TL;DR: In this paper, a decentralized event-triggered implementation, over sensor/actuator networks, of centralized nonlinear controllers is presented, which reduces the number of recomputations and thus of transmissions, while guaranteeing desired levels of control performance.
Abstract: Event-triggered control has been recently proposed as an alternative to the more traditional periodic execution of control tasks. In a typical event-triggered implementation, the control signals are kept constant until the violation of a condition on the state of the plant triggers the recomputation of the control signals. The possibility of reducing the number of recomputations, and thus of transmissions, while guaranteeing desired levels of control performance, makes event-triggered control very appealing in the context of sensor/actuator networks. In particular, by reducing the network traffic we also reduce the energy expenditures of battery powered wireless sensor nodes. In this paper we present a decentralized event-triggered implementation, over sensor/actuator networks, of centralized nonlinear controllers.

641 citations

Journal ArticleDOI
TL;DR: The evolution of manufacturing system paradigms is discussed to identify the requirements of decision support systems in dynamic and distributed environments; recent advances in IT are overviewed and associated with next-generation manufacturing paradigm; and the relation of IT infrastructure and ESs is explored to identified the technological gaps in adopting IoT as an IT infrastructure of ESs.
Abstract: Design and operation of a manufacturing enterprise involve numerous types of decision-making at various levels and domains. A complex system has a large number of design variables and decision-making requires real-time data collected from machines, processes, and business environments. Enterprise systems (ESs) are used to support data acquisition, communication, and all decision-making activities. Therefore, information technology (IT) infrastructure for data acquisition and sharing affects the performance of an ES greatly. Our objective is to investigate the impact of emerging Internet of Things (IoT) on ESs in modern manufacturing. To achieve this objective, the evolution of manufacturing system paradigms is discussed to identify the requirements of decision support systems in dynamic and distributed environments; recent advances in IT are overviewed and associated with next-generation manufacturing paradigms; and the relation of IT infrastructure and ESs is explored to identify the technological gaps in adopting IoT as an IT infrastructure of ESs. The future research directions in this area are discussed.

595 citations

Journal ArticleDOI
TL;DR: The Internet of Nano Things and Tactile Internet are driving the innovation in the H-IoT applications and the future course for improving the Quality of Service (QoS) using these new technologies are identified.
Abstract: The impact of the Internet of Things (IoT) on the advancement of the healthcare industry is immense. The ushering of the Medicine 4.0 has resulted in an increased effort to develop platforms, both at the hardware level as well as the underlying software level. This vision has led to the development of Healthcare IoT (H-IoT) systems. The basic enabling technologies include the communication systems between the sensing nodes and the processors; and the processing algorithms for generating an output from the data collected by the sensors. However, at present, these enabling technologies are also supported by several new technologies. The use of Artificial Intelligence (AI) has transformed the H-IoT systems at almost every level. The fog/edge paradigm is bringing the computing power close to the deployed network and hence mitigating many challenges in the process. While the big data allows handling an enormous amount of data. Additionally, the Software Defined Networks (SDNs) bring flexibility to the system while the blockchains are finding the most novel use cases in H-IoT systems. The Internet of Nano Things (IoNT) and Tactile Internet (TI) are driving the innovation in the H-IoT applications. This paper delves into the ways these technologies are transforming the H-IoT systems and also identifies the future course for improving the Quality of Service (QoS) using these new technologies.

446 citations

Proceedings Article
01 Jan 2005
TL;DR: In this article, the authors investigate the relationship between optimal control design and control allocation when the performance indexes are quadratic in the control input and show that for a particular class of nonlinear systems, they give exactly the same design freedom in distributing the control effort among the actuators.
Abstract: This paper considers actuator redundancy management for a class of overactuated nonlinear systems. Two tools for distributing the control effort among a redundant set of actuators are optimal control design and control allocation. In this paper, we investigate the relationship between these two design tools when the performance indexes are quadratic in the control input. We show that for a particular class of nonlinear systems, they give exactly the same design freedom in distributing the control effort among the actuators. Linear quadratic optimal control is contained as a special case. A benefit of using a separate control allocator is that actuator constraints can be considered, which is illustrated with a flight control example.

341 citations