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- Pain overview: classification, conceptual framework, and assessmentPublication . Duarte, Nuno M.; Garcia-Pedraza, José A.; Santos, Marlene E.The ability to evict noxious stimulus increases the likelihood of surviving. It is the result of interactions between specialized cells, the spinal cord, and the brain. Nociceptive pain is related to direct injury of the body. Other forms of pain may not be linked to visible injury. Being multidimensional in nature, classification attempts are unable to embark the plethora of elements that constitute pain. Pain theories can explain the nociceptive quality of it while failing to explain other qualities. Efforts culminated in the development of gate control theory, which spawned many advances in pain management. Assessment tools are useful to determine the intensity of pain and its impact on quality of life. Judicious use of these scales allows healthcare professionals to proper manage patients pain and are validated instruments widely used in research. This short review aims to expand awareness about the phenomenon of pain, its mechanisms, and its measurement.
- A scalable and efficient approach for obtaining measurements in CAN-Based control systemsPublication . Andersson, Björn; Pereira, Nuno; Elmenreich, Wilfried; Tovar, Eduardo; Pacheco, Filipe; Cruz, NunoThe availability of small inexpensive sensor elements enables the employment of large wired or wireless sensor networks for feeding control systems. Unfortunately, the need to transmit a large number of sensor measurements over a network negatively affects the timing parameters of the control loop. This paper presents a solution to this problem by representing sensor measurements with an approximate representation-an interpolation of sensor measurements as a function of space coordinates. A priority-based medium access control (MAC) protocol is used to select the sensor messages with high information content. Thus, the information from a large number of sensor measurements is conveyed within a few messages. This approach greatly reduces the time for obtaining a snapshot of the environment state and therefore supports the real-time requirements of feedback control loops.
- Cyber-physical systems clouds: A surveyPublication . Rihab, Chaari; Ellouze, Fatma; Koubâa, Anis; Qureshi, Basit; Pereira, Nuno; Youssef, Habib; Tovar, EduardoCyber-Physical Systems (CPSs) represent systems where computations are tightly coupled with the physical world, meaning that physical data is the core component that drives computation. Industrial automation systems, wireless sensor networks, mobile robots and vehicular networks are just a sample of cyber-physical systems. Typically, CPSs have limited computation and storage capabilities due to their tiny size and being embedded into larger systems. With the emergence of cloud computing and the Internet-of-Things (IoT), there are several new opportunities for these CPSs to extend their capabilities by taking advantage of the cloud resources in different ways. In this survey paper, we present an overview of research efforts on the integration of cyber-physical systems with cloud computing and categorize them into three areas: (1) remote brain, (2) big data manipulation, (3) and virtualization. In particular, we focus on three major CPSs namely mobile robots, wireless sensor networks and vehicular networks.
- A microscope for the data centerPublication . Pereira, Nuno; Tennina, Stefano; Loureiro, João; Severino, Ricardo; Saraiva, Bruno; Santos, Manuel; Pacheco, Filipe; Tovar, EduardoNowadays, data centers are large energy consumers and the trend for next years is expected to increase further, considering the growth in the order of cloud services. A large portion of this power consumption is due to the control of physical parameters of the data center (such as temperature and humidity). However, these physical parameters are tightly coupled with computations, and even more so in upcoming data centers, where the location of workloads can vary substantially due, for example, to workloads being moved in the cloud infrastructure hosted in the data center. Therefore, managing the physical and compute infrastructure of a large data center is an embodiment of a Cyber-Physical System (CPS). In this paper, we describe a data collection and distribution architecture that enables gathering physical parameters of a large data center at a very high temporal and spatial resolution of the sensor measurements. We think this is an important characteristic to enable more accurate heat-flow models of the data center and with them, find opportunities to optimize energy consumptions. Having a high-resolution picture of the data center conditions, also enables minimizing local hot-spots, perform more accurate predictive maintenance (failures in all infrastructure equipments can be more promptly detected) and more accurate billing. We detail this architecture and define the structure of the underlying messaging system that is used to collect and distribute the data. Finally, we show the results of a preliminary study of a typical data center radio environment.
- Networked embedded systems for active flow control in aircraftPublication . Tovar, Eduardo; Pereira, Nuno; Bate, Iain; Indrusiak, Leandro; Penna, Sérgio; Negrão, José; Viana, Júlio C.; Philipp, François; Mayer, Dirk; Heras, José; Pacheco, Filipe; Loureiro, JoãoAerodynamic drag is known to be one of the factors contributing more to increased aircraft fuel consumption. The primary source of skin friction drag during flight is the boundary layer separation. This is the layer of air moving smoothly in the immediate vicinity of the aircraft. In this paper we discuss a cyber-physical system approach able of performing an efficient suppression of the turbulent flow by using a dense sensing deployment to detect the low pressure region and a similarly dense deployment of actuators to manage the turbulent flow. With this concept, only the actuators in the vicinity of a separation layer are activated, minimizing power consumption and also the induced drag.
- Static-priority scheduling over wireless networks with multiple broadcast domainsPublication . Pereira, Nuno; Andersson, Björn; Tovar, Eduardo; Rowe, AnthonyWe propose a wireless medium access control (MAC) protocol that provides static-priority scheduling of messages in a guaranteed collision-free manner. Our protocol supports multiple broadcast domains, resolves the wireless hidden terminal problem and allows for parallel transmissions across a mesh network. Arbitration of messages is achieved without the notion of a master coordinating node, global clock synchronization or out-of-band signaling. The protocol relies on bit-dominance similar to what is used in the CAN bus except that in order to operate on a wireless physical layer, nodes are not required to receive incoming bits while transmitting. The use of bit-dominance efficiently allows for a much larger number of priorities than would be possible using existing wireless solutions. A MAC protocol with these properties enables schedulability analysis of sporadic message streams in wireless multihop networks.
- Collision-free prioritized medium access control in wireless networks with hidden nodesPublication . Andersson, Björn; Pereira, Nuno; Tovar, EduardoWe propose a collision-free medium access control (MAC) protocol, which implements static-priority scheduling and works in the presence of hidden nodes. The MAC protocol allows multiple masters and is fully distributed; it is an adaptation to a wireless channel of the dominance protocol used in the CAN bus. But unlike that protocol, our protocol does not require a node having the ability to sense the channel while transmitting to the channel. Our protocol is collision-free even in the presence of hidden nodes and it achieves this without synchronized clocks or out-of-band busy tones. In addition, the protocol is designed to ensure that many non-interfering nodes can transmit in parallel and it functions for both broadcast and unicast transmissions.
- Dependable Embedded Wireless InfrastructurePublication . Pereira, NunoDEWI will provide key solutions for wireless seamless connectivity and interoperability in the everyday physical environment of citizens, thereby significantly contributing to the emerging smart home and smart public space.
- Delay-bounded medium access for unidirectional wireless linksPublication . Andersson, Björn; Pereira, Nuno; Tovar, EduardoConsider a wireless network where links may be unidirectional, that is, a computer node A can broadcast a message and computer node B will receive this message but if B broadcasts then A will not receive it. Assume that messages have deadlines. We propose a medium access control (MAC) protocol which replicates a message in time with carefully selected pauses between replicas, and in this way it guarantees that for every message at least one replica of that message is transmitted without collision. The protocol ensures this with no knowledge of the network topology and it requires neither synchronized clocks nor carrier sensing capabilities. We believe this result is significant because it is the only MAC protocol that offers an upper bound on the message queuing delay for unidirectional links without relying on synchronized clocks.
- Smartphone-based Transport Mode Detection for Elderly CarePublication . Cardoso, Nuno; Madureira, João; Pereira, NunoSmartphones are everywhere, and they are a very attractive platform to perform unobtrusive monitoring of users. In this work, we use common features of modern smartphones to build a human activity recognition (HAR) system for elderly care. We have built a classifier that detects the transport mode of the user including whether an individual is inactive, walking, in bus, in car, in train or in metro. We evaluated our approach using over 24 hours of transportation data from a group of 15 individuals. Our tests show that our classifier can detect the transportation mode with over 90% accuracy.