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The development of Directional Medium Access Control (DMAC) strategies that allow to enhance the limitations due to the use of omnidirectional antennas in Mobile ad Hoc Networks (MANET), introduces several issues that need to be properly addressed such as the Deafness problem. The use of Smart Antenna Systems (SAS) along with Directional Request To Send (DRTS) and Directional Clear To Send (DCTS) could be not sufficient to mitigate the Deafness. In this regard, a sectorized antenna approach together with a frame scheduling mechanism can improve the overall MAC performance while limiting the Deafness; however, the employment of scheduling algorithms without priority such as the Round Robin could limit the network performance especially in terms of Packet Delivery Ratio (PDR) and fairness. For this reason, we propose two approaches: the A-MSDU (Aggregation MAC Service Data Unit) MAC and a WRR (Weighted Round Robin) MAC that could allow to overcome the limitations of the Round Robin scheme applied at MAC layer in order to have an high efficiency in the overall resource allocation. More specifically, obtained results show that, through the use of frame aggregation, it is possible to considerably reduce issues implied by Round Robin such as time slice and network overhead; WRR approach, instead, is able to enhance the overall network fairness by reducing the number of collisions provided by a directional MAC based on Round Robin scheduling; this aspect translates into higher PDR performance compared to Round Robin approach.

With the rise of both embedded technologies and the Internet of Things (IoT) integration, it is increasingly possible to realize complex systems in which, for example, vehicles are connected to the IoT domain capable of interacting directly with applications on mobile or embedded devices. In this work, a Machine to Machine (M2M) based platform able to recognize the driving style will be presented. An embedded device (On-Board Diagnostic (OBD)) has been considered to implement the Internet of Vehicles (IoV) paradigm exporting recognized data to other systems to promote an eco-friendly driving style by suggesting corrective actions to drivers. The architecture consists of the following elements: an on board device able to obtain information regarding speed, acceleration, jerk and fuel consumption, a cloud able to store all collected data, an M2M protocol such as Message Queuing Telemetry Transport (MQTT) to provide scalability to the architecture, and a Fuzzy Inference System to classify user behavior. All these elements are harmonized to achieve the common target of informing users about an Aggressive or Very-Aggressive driving style with the aim of reducing both speed and acceleration. The smart alerting system will promote a more eco-friendly driving style, contributing a reduction in CO 2 emissions and fuel consumption. Performance evaluation confirms the efficiency of the proposed classifier and the overall benefits for drivers in fuel consumption reduction.

This work addresses the coordination problem of multiple robots with the goal of finding specific hazardous targets in an unknown area and dealing with them cooperatively. The desired behaviour for the robotic system entails multiple requirements, which may also be conflicting. The paper presents the problem as a constrained bi-objective optimization problem in which mobile robots must perform two specific tasks of exploration and at same time cooperation and coordination for disarming the hazardous targets. These objectives are opposed goals, in which one may be favored, but only at the expense of the other. Therefore, a good trade-off must be found. For this purpose, a nature-inspired approach and an analytical mathematical model to solve this problem considering a single equivalent weighted objective function are presented. The results of proposed coordination model, simulated in a two dimensional terrain, are showed in order to assess the behaviour of the proposed solution to tackle this problem. We have analyzed the performance of the approach and the influence of the weights of the objective function under different conditions: static and dynamic. In this latter situation, the robots may fail under the stringent limited budget of energy or for hazardous events. The paper concludes with a critical discussion of the experimental results., Comment: 40 pages

Recently the topic of health monitoring is growing in interest and several applications and devices were designed and put on the markets. This interest is promoted by an increasing enthusiasm about physical activities to improve health and wellness. In this work, we present a wearable device able to collect data from different body sensors to send them towards a cloud platform. The Message Queuing Telemetry Transport MQTT communication protocol is used to send data by customizing the messages payload and building up a customized protocol between devices and cloud. These data, are used to recognize user activity and health status sending alerts when an anomaly is detected. These results can be used to monitor performances or to investigate anomalies discovered during activities. In addition, we propose a fuzzy-based Human Activity Recognition (HAR) classifier which continuously acquire data from body sensors exploiting an Internet of Things (IoT) architecture. In order to improve HAR, different classes of data filters have been analyzed to reduce the amount of data sent to the cloud. These filters introduce smart functionalities at the edge of the network reducing the data-flow without compromising the classifier goodness. A smart device based on embedded technologies is designed to realize the wearable device.

From many years, the methods to defend against Denial of Service attacks have been very attractive from different point of views, although network security is a large and very complex topic. Different techniques have been proposed and so-called packet marking and IP tracing procedures have especially demonstrated a good capacity to face different malicious attacks. While host-based DoS attacks are more easily traced and managed, network-based DoS attacks are a more challenging threat. In this paper, we discuss a powerful aspect of the IP traceback method, which allows a router to mark and add information to attack packets on the basis of a fixed probability value. We propose a potential method for modeling the classic probabilistic packet marking algorithm as Markov chains, allowing a closed form to be obtained for evaluating the correct number of received marked packets in order to build a meaningful attack graph and analyze how marking routers must behave to minimize the overall overhead.

Security in the context of Internet of Things (IoT) is a critical challenge. The purpose of this work is to model and evaluate a dynamic IoT security system based on a generic IoT edge network in which nodes exchange messages through the Message Queue Telemetry Transport (MQTT) protocol. This work aims to increase MQTT security by mitigating data tampering, eavesdropping and Replay attacks by using the Elliptic Curve Cryptography (ECC), timestamps and wake up patterns, with the purpose of preserving node energy. The evaluated results will show that it is possible to increase the system lifetime by linking security levels and energy.

Ultra wideband (UWB) systems are communication systems based on a baseband impulsive transmission that has recently excited interest both in the commercial and academic fields. Physical layer aspects and MAC protocols have been intensively investigated in the recent years leading, in some cases, to important and definitive results. However, many questions relating to the UWB network layer are still open. The aim of this paper is to investigate the network layer of the UWB system: for this purpose a new routing protocol called Interference Aware-based Ad-Hoc On Demand Distance Vector (IA-AODV) and based on the interference concept has been proposed. In particular, two distinct metrics are explained in detail: the first one is based on the concept of global interference perceived by each node; the second one is based on the concept of link interference perceived by a node on a wireless path to a generic neighbor. Finally, a comparative analysis between our protocol and Ad-Hoc On Demand Distance Vector (AODV) protocol are carried out in order to show the soundness of our proposal.

Untethered nodes in mobile ad hoc networks strongly depend on the efficient use of their batteries. Despite the fact that devices are getting smaller and more powerful, advances in battery technology have not yet reached the stage where devices can autonomously operate for days. At the network layer, routing protocols may balance power consumption at nodes according to their routing decisions. In this paper, an in-depth performance comparison of the DSR (Dynamic Source Routing) and the OLSR (Optimized Link State Routing) is presented in terms of energy consumption. Using the ns-2 simulator an evaluation is made of how the different approaches affect the energy use of mobile devices. It was found that a reactive protocol takes advantage of its routing policy when the traffic load is low. However, at higher traffic rates, a proactive routing protocol can perform better with an appropriate refresh parameter. Also, it is demonstrated that independently of the routing protocol selected, the overhearing activity can seriously affect performance. To the best of our knowledge, this is the first simulation study addressing the power saving issue to extensively compare the DSR and OLSR protocols under a wide variety of networking scenarios.

A QoS multicast routing scheme based on Genetic Algorithms (GA) heuristic is presented in this paper. Our proposal, called Constrained Cost-Bandwidth-Delay Genetic Algorithm (CCBD-GA), is applied to a multilayer hybrid platform that includes High Altitude Platforms (HAPs) and a Satellite platform. This GA scheme has been compared with another GA well-known in the literature called Multi-Objective Genetic Algorithm (MOGA) in order to show the proposed algorithm goodness. In order to test the efficiency of GA schemes on a multicast routing protocol, these GA schemes are inserted into an enhanced version of the Core-Based Tree (CBT) protocol with QoS support. CBT and GA schemes are tested in a multilayer hybrid HAP and Satellite architecture and interesting results have been discovered. The joint bandwidth-delay metrics can be very useful in hybrid platforms such as that considered, because it is possible to take advantage of the single characteristics of the Satellite and HAP segments. The HAP segment offers low propagation delay permitting QoS constraints based on maximum end-to-end delay to be met. The Satellite segment, instead, offers high bandwidth capacity with higher propagation delay. The joint bandwidth-delay metric permits the balancing of the traffic load respecting both QoS constraints. Simulation results have been evaluated in terms of HAP and Satellite utilization, bandwidth, end-to-end delay, fitness function and cost of the GA schemes.

This paper presents a scalable routing protocol for very large and dense ad hoc networks. The scalability of ad hoc networks is becoming an important issue due to the increasing number of applications in a distributed environment, the great number of mobile nodes involved into communication and wide speed range in which the mobile nodes can move. It is important to offer scalability in terms of network size, traffic load and mobility speed. The proposed protocol, called Geo-LANMAR, inherits the same advantage of LANMAR protocol in terms of group motion support and traffic load scalability and it reflects also the behaviour of geo-routing protocols such as GPSR. Geo-LANMAR is based on the idea of Terminodes routing for the forwarding scheme: long-distance geo-forwarding and low-distance table-driven routing. Its updating scheme, instead, is similar to the Hazy Sighted Link State Routing (HSLS) through a spatial and time update rate differentiation: frequent update rate for short distance and lower update rate for long distance. Performance evaluation of Geo-LANMAR has been lead out and a comparison in terms of throughput, average end-to-end delay and control overhead has been conducted against other well-known protocols such as LANMAR, GPSR and AODV. Geo-LANMAR results scalable in terms of traffic load, mobility speed, number of nodes and number of groups.