Vincenzo Mighali

A novel MAC scheduler to minimize the energy consumption in a Wireless Sensor Network

The rising success of the Internet of Things has led the Wireless Sensor Networks to play an important role in many fields, ranging from military to civilian applications. However, since sensor nodes are battery powered, communication protocols and applications for these networks must be carefully designed in order to limit the power consumption. In this work, a new MAC protocol able to significantly reduce the power consumption and compatible with the IEEE 802.15.4 standard, is designed and validated. The defined protocol is based on an efficient setting of the nodes duty cycle as a function of the transmission times of the neighbor nodes. In a duty cycle period, each node wakes up once to transmit and N times to receive, where N is the number of neighbors, while it remains in sleep mode for the rest of the time. The defined protocol has been validated through both an analytical and a simulative approach. By using the first approach, the proposed solution is compared with another energy-efficient protocol, namely AS-MAC; then, the differences between the simulated scenario and the analytical one are analyzed. By using the second approach (through Omnet++ simulator), we carried out a performance comparison between our protocol and the current MAC protocol compliant with the ZigBee standard. All the results have shown the effectiveness of the proposed solution, which has proved to be flexible and efficient, since it is able to provide high energy savings at different date rate, without a negative impact on the packets delivery.

A Software Architecture Enabling the Web of Things

The Internet of Things (IoT) will include billions of smart “things” connected to the Web and characterized by sensing, actuating, and data processing capabilities. In this context, also known as Web of Things (WoT), the user should ideally be able to collect information provided by smart things, and to mash-up them to obtain value-added services. However, in the current solutions, the access to physical objects is poorly scalable and efficient, the communications are often unidirectional (from the devices to the users), and only tech-savvy people are able to develop mash-up applications. Based on these assumptions, we propose a software architecture to easily mash-up constrained application protocol (CoAP) resources. It is able to discover the available devices and to virtualize them outside the physical network. These virtualizations are then exposed to the upper layers by a REpresentational State Transfer (REST) interface, so that the physical devices interact only with their own virtualization. Furthermore, the system provides simplified tools allowing the development of mash-up applications to different-skilled users. Finally, the architecture allows not only to monitor but also to control the devices, thus establishing a bidirectional communication channel. To evaluate the proposal, we deeply modify and integrate some existing software components to realize an instance of the architecture.

Performance Evaluation of UHF RFID Tags in the Pharmaceutical Supply Chain

The item-level tagging is one of the main challenges in the pharmaceutical distribution in order to improve track and trace systems. The RFID technology will play a very important role in development of auto-identification solutions. In this chapter, we focus on the use of passive UHF tags, in order to analyze a performance comparison between near field and far field UHF RFID systems. Some different passive UHF tags, suitably chosen, have been tested at item-level, i.e., on each single medicine package, simulating each stage of the pharmaceutical supply chain in a controlled laboratory environment. The obtained experimental results, in terms of successful read rates, have shown that the use of passive far field UHF tags represents an advantage solution to guarantee high performance in an item-level tracing system in the whole supply chain.

A novel architecture enabling the visual implementation of web of Things applications

The concept of Internet of Things is becoming one of the key aspects for the future Internet, where embedded devices will be responsible for collecting data from the surrounding environment and making them available to useful mash-up applications. In order to guarantee a high feasibility of this scenario, it would be appropriate to have a flexible and intuitive architecture for the implementation of such applications without knowing specific details about the constrained hardware and operating system. Therefore, in this work, a software system for the graphical development of mash-up applications, dedicated to Wireless Sensor Networks, was designed and implemented. It is based on a Constrained Application Protocol application server, called Actinium, and on a graphical editor, called ClickScript. Especially the latter one has been substantially modified in order to communicate with Actinium and to interact with the constrained resources made available by the WSN. The effectiveness of the proposed solution has been tested through a real use case that has demonstrated the validity of the whole system.

Near Field UHF RFID Antenna System Enabling the Tracking of Small Laboratory Animals

Radio frequency identification (RFID) technology is more and more adopted in a wide range of applicative scenarios. In many cases, such as the tracking of small-size living animals for behaviour analysis purposes, the straightforward use of commercial solutions does not ensure adequate performance. Consequently, both RFID hardware and the control software should be tailored for the particular application. In this work, a novel RFID-based approach enabling an effective localization and tracking of small-sized laboratory animals is proposed. It is mainly based on a UHF Near Field RFID multiantenna system, to be placed under the animals’ cage, and able to rigorously identify the NF RFID tags implanted in laboratory animals (e.g., mice). Once the requirements of the reader antenna have been individuated, the antenna system has been designed and realized. Moreover, an algorithm based on the measured Received Signal Strength Indication (RSSI) aiming at removing potential ambiguities in data captured by the multiantenna system has been developed and integrated. The animal tracking system has been largely tested on phantom mice in order to verify its ability to precisely localize each subject and to reconstruct its path. The achieved and discussed results demonstrate the effectiveness of the proposed tracking system.

A location-aware architecture for heterogeneous building automation systems

Smart Objects and Smart Environments are expected to become two of the leaders of the future Internet of Things. In this context, the Smart Homes are getting more and more attention, since people are very attracted by the idea of a home environment able to automatically meet their needs. However, the heterogeneity of the smart devices, the difficulty in automating the user-home interaction, and the poor involvement of the users in the development process of new services and applications still represent very debated issues. So, in this paper, we propose an architecture able to overcome the heterogeneity of smart devices and that can be easily extended to new future technologies. To maximize the User Experience, the proposed architecture automatically manages the environment basing on users-defined rules and on people movements, by exploiting an indoor location service based on Bluetooth Low Energy. Finally, the system also provides a simplified development tool that allows even common users to develop new services for Smart Homes and mobile applications to directly interact with the home environment. As a proof-of-concept, the first development steps are described in this paper.

Vertical Handover Algorithm for Heterogeneous Wireless Networks

Recently, there has been much effort to integrate heterogeneous wireless technologies in order to make overlay networks able to provide mobile users with ubiquitous Internet access. Handover management is still one of the most challenging issues to be solved for seamless integration of wireless networks. In this paper, an algorithm for vertical handover with QoS guarantees between IEEE 802.16e and IEEE 802.11e networks, without computational complexity added on mobile nodes, has been proposed. It uses a decision mechanism based on the following metrics: the available bandwidth, the Signal-to-Noise Ratio (SNR) and the access delay. Its characteristics are perfectly compatible with the guidelines specified in the IEEE 802.21 standard. The effectiveness of the defined algorithm has been evaluated, using the ns-2 tool, in terms of Packet Loss Rate (PLR), satisfaction of minimum applications requirements and number of useless handovers. The performance of the defined algorithm has been compared with that obtained by using the algorithm suggested by IEEE 802.21 standard that exploits only the SNR in the decision procedure.

Performance evaluation of end-to-end security protocols in an Internet of Things

Wireless Sensor Networks are destined to play a fundamental role in the next-generation Internet, which will be characterized by the Machine-to-Machine paradigm, according to which, embedded devices will actively exchange information, thus enabling the development of innovative applications. It will contribute to assert the concept of Internet of Things, where end-to-end security represents a key issue. In such context, it is very important to understand which protocols are able to provide the right level of security without burdening the limited resources of constrained networks. This paper presents a performance comparison between two of the most widely used security protocols: IPSec and DTLS. We provide the analysis of their impact on the resources of embedded devices. For this purpose, we have modified existing implementations of both protocols to make them properly run on our hardware platforms, and we have performed an extensive experimental evaluation study. The achieved results are not a consequence of a classical simulation campaign, but they have been obtained in a real scenario that uses software and hardware typical of the current technological developments. Therefore, they can help network designers to identify the most appropriate secure mechanism for end-to-end IP communications involving constrained devices.

An RFID tracking system supporting the behavior analysis of colonial laboratory animals

Animal tracking and animal behavior analysis have a crucial impact in biomedical disciplines to study new pathologies and effects of new drugs. There are several solutions, based on different technologies such as GPS, radar, and vision, designed to obtain animals tracking systems, but they are effective mainly in presence of large size animals and outdoor environment. Unfortunately, they show poor performance when groups of small laboratory animals have to be monitored in indoor environments. In such a context, the adoption of passive Near Field (NF) Ultra High Frequency (UHF) Radio Frequency Identification (RFID) technology seems to be a winning approach, even though the straightforward use of commercial solutions does not guarantee satisfactory performance. Specifically, customized hardware and software solutions are then required. The main goal of this work is to present the development and then to validate a reliable and effective system for the automatic tracking of laboratory mice, based on suited NF UHF RFID hardware capturing system combined with an ad hoc software system able to guarantee hardware control, data processing, and reporting. In particular, the validation phase has been carried out by selecting the most appropriate RFID tags and by surgically implanting them into laboratory mice. Experimental results have demonstrated the efficiency of the proposed solution, which is able to gather data on the animal movements, allowing their subsequent processing for a satisfactory behavioral analysis.

A smart remote elderly monitoring system based on IoT technologies

The aging population phenomenon is more and more increasing. In this context, the elderlys behavioral analysis through the Internet of Things technologies can help to prevent Mild Cognitive Impairment and frailty problems. In particular, since movements and body motility are good indicators of behavioral changes, this work aims to define a reliable system for controlling the position and the body motility of the elderly in unobtrusive, low-cost and low-power way. The system represents the basis of a complete architecture for behavioral analysis and risk detection developed within the City4Age project, funded by the Horizon 2020 Programme of the European Commission.