Abstract
The adoption of sensors-based monitoring systems supported by Internet of Things technologies has opened new possibilities for data retrieving and processing in urban areas. Among such possibilities, emergencies management is expected to play an important role in how modern cities will evolve, reducing the negative impacts of critical events and improving the quality of life perceived by their inhabitants. Actually, when an emergency is detected and alerted, emergency vehicles, notably ambulances, fire trucks, police cars and transit agents vehicles, should be quickly assigned to respond to that situation, as soon as possible. In this context, we propose a dynamic algorithm to automatically assign emergency vehicles in smart city scenarios, exploiting for that a sensors-based emergency detection system to provide emergency alerts. The proposed algorithm can then be used to quickly assign a number of emergency vehicles in the first moments of an emergency, which can potentially save lives and improve existing crisis management applications in smart cities. © 2020 IEEE.

Abstract
IEC 61850 is a standard for the design and operation of electrical Substation Automation Systems (SAS) that defines how data may be transferred among Intelligent Electronic Devices (IEDs). The defined data models can be mapped into application protocols, such as SV or GOOSE, which may run upon high speed Ethernet LANs bridged by IEEE 802.1Q compliant switches. The communication system must cope with the timing requirements associated to protective relaying strategies. Given the time constrained nature of SAS applications, a thorough analysis of its timing behavior is required. In this paper, we propose an analytical model for the timing assessment of SV and GOOSE message exchanges in an IEC 61850 process bus. The proposed model allows the communication timing assessment, by analyzing the response time of each message stream of the SAS. This feature is an advantage for the expansion of the SAS, as it allows the evaluation at design time of the maximum number of IEDs that can be supported by the underlying communication system. The results from the proposed analytical model were validated for a typical IEC 61850 communication scenario, both through simulation and through an experimental assessment with IEC 61850 compliant equipment.

Abstract
Cooperative diversity techniques are being used to improve the communication reliability in Wireless Sensor Networks (WSN). Typically, these techniques use relay nodes to retransmit messages that otherwise would not be heard by their destination nodes. Thus, the relay selection techniques are fundamental to improve WSN's communication behavior. However, to perform the adequate relay selection, it is necessary to identify which are the most relevant parameters for the operation of the network and analyze their impact when used in the relay selection, that is, it is necessary to define which are the best parameters to use as selection criteria. In this context, this paper performs an analysis of the impact of each of the parameters used to perform the relay selection in the Optimized Relay Selection Technique (ORST). This analysis was assessed by simulation using the OMNeT++ tool and the WSN framework Castalia. It was considered a set of parameters, aiming to identify their relevance and possibly optimize the objective function used in this technique. Simulation results show that the objective function can be optimized considering a small number of parameters to perform the relay selection.

Abstract
The use of sensing devices to perform monitoring tasks has continuously evolved in the past decades [...]

Abstract

Abstract
Cluster-tree topologies are commonly employed in large-scale Wireless Sensor Networks applications where nodes are randomly deployed. This topology presents several challenges related to connectivity and message schedulability. As a consequence, effective methods for network formation and operation are required. This work proposes a combination of methods of neighborhood discovery, network formation and message scheduling to deal with this problem. This proposal aims to build a flexible network, with better performance and is also able to adapt for different scenarios. Simulation results highlight significant improvements of the network performance, when compared to the use of LEACH protocol.