Showing papers by "Gianluca Cena published in 2022"
TL;DR: In this paper , an extensive experimental campaign has been carried out through discrete event simulation to determine what consequences above errors may have from both a functional and performance viewpoint, and different solutions can be profitably adopted depending on the specific operating conditions.
Abstract: Lifetime of motes in wireless sensor networks can be enlarged by decreasing the energy spent for communication. Approaches like time slotted channel hopping pursue this goal by performing frame exchanges according to a predefined schedule, which helps reducing the duty cycle. Unfortunately, whenever the receiving radio interface is active but nobody in the network is transmitting, idle listening occurs. If the traffic pattern is known in advance, as in the relevant case of periodic sensing, proactive reduction of idle listening (PRIL) noticeably lowers energy waste by disabling receivers when no frames are expected for them. Optimal PRIL operation demands that, at any time, the transmitter and receiver sides of a link have a coherent view of its state (either enabled or disabled). However, this is not ensured in the presence of acknowledgment frame losses. This article presents and analyzes some strategies to cope with such events. An extensive experimental campaign has been carried out through discrete event simulation to determine what consequences above errors may have from both a functional and performance viewpoint. Results show that, although no strategy is optimal in all circumstances, different solutions can be profitably adopted depending on the specific operating conditions.
2 citations
27 Apr 2022
TL;DR: A slight modification is proposed for the basic CAN access mechanism that permits a group of objects to be served by the network with about the same quality of service and provides fair treatment to a number of block transfers initiated by different nodes and taking place contextually over the bus.
Abstract: Controller Area Network is still the most popular solution for in-vehicle communications in automotive scenarios. Recent solutions like CAN FD and CAN XL manage to reduce the performance gap with Ethernet-based solutions. Nevertheless, the priority-based access mechanism they rely on is not completely adequate to support fragmented transfers of large blocks of data, as happens, e.g., for driver assistance and the Internet of Things. In this paper, a slight modification is proposed for the basic CAN access mechanism that permits a group of objects to be served by the network with about the same quality of service. This provides fair treatment to a number of block transfers initiated by different nodes and taking place contextually over the bus.
1 citations
06 Sep 2022
TL;DR: This paper analyzed and compared the performance of two approaches, based on simple moving averages and artificial neural networks, respectively, to carry out predictions for a real Wi-Fi link, and confirmed that reliable estimates about the packet delivery ratio can be obtained in realistic operating conditions by averaging the recent past.
Abstract: Communication quality of wireless links unavoidably varies over time, for a number of reasons that are mostly unknown in the design phase of distributed systems. This is a severe limitation when such network technologies are employed to connect devices and subsystems in industrial applications, where high reliability and timeliness are customarily demanded. The ability to foresee, to some extent, the quality of a link in the near future is likely to provide clear benefits in many such cases.In this paper, we analyzed and compared the performance of two approaches, based on simple moving averages and artificial neural networks, respectively, to carry out predictions for a real Wi-Fi link. Results confirm that reliable estimates about the packet delivery ratio can be obtained in realistic operating conditions by averaging the recent past, and that the use of machine learning may improve prediction further.
1 citations
27 Apr 2022
TL;DR: The effectiveness of CONSIP was assessed by means of an experimental campaign, and the only drawback is that the backup cell, which is required to be reserved per link, may limit the number of nodes in dense networks.
Abstract: The use of white and black listing techniques in Wireless Sensor Networks (WSN), and in particular those which are based on the Time Slotted Channel Hopping (TSCH) op-erating mode of IEEE 802.15.4, permits to improve reliability and latency by performing transmissions on the best channels. Techniques that operate on a per-link basis are deemed quite effective, but proper operation requires that the two end points involved in the communication agree on the channels to be used for transmission. On the contrary, communication in the network can be prevented, eventually leading, in the worst cases, to the disconnection of part of the nodes. This paper presents CONSIP, a technique aimed to ensure strict consistency in the information exchanged between the nodes and used to drive communication, by preventing a priori the aforementioned problem from occurring. Results show a slight increase in energy consumption, due to the use of a backup cell, whereas communication latency does not worsen. The effectiveness of CONSIP was assessed by means of an experimental campaign, and the only drawback we found is that the backup cell, which is required to be reserved per link, may limit the number of nodes in dense networks.
06 Sep 2022
TL;DR: In this article , the authors propose QRscript, a high-level programming language written in a high level programming language to be encoded in a QR code and the opposite process that, starting from the QR code, executes it by means of a virtual machine.
Abstract: Embedding a programming language in a QR code is a new and extremely promising opportunity, as it makes devices and objects smarter without necessarily requiring an Internet connection. In this paper, all the steps needed to translate a program written in a high-level programming language to its binary representation encoded in a QR code, and the opposite process that, starting from the QR code, executes it by means of a virtual machine, have been carefully detailed. The proposed programming language was named QRscript, and can be easily extended so as to integrate new features.One of the main design goals was to produce a very compact target binary code. In particular, in this work we propose a specific sub-language (a dialect) that is aimed at encoding decision trees. Besides industrial scenarios, this is useful in many other application fields. The reported example, related to the configuration of an industrial networked device, highlights the potential of the proposed technology, and permits to better understand all the translation steps.
27 Apr 2022
TL;DR: A proposal is described that exploits redundant MQTT brokers, deployed in different geographic locations, whose aim is to provide uninterrupted service in spite of failures that may be affecting both the servers executing the middleware and the Internet core.
Abstract: Among the application layer protocols that support the Internet of Things, a very popular option is MQTT. Its main advantages reside in the inherent simplicity, which makes it suitable for embedded devices too, and the publisher-subscriber model it relies on, which decouples data sources and sinks and enables efficient multicast streaming over the Internet. In this paper a proposal is described that exploits redundant MQTT brokers, deployed in different geographic locations, whose aim is to provide uninterrupted service in spite of failures that may be affecting both the servers executing the middleware and the Internet core. Unlike routing algorithms and protocols, seamless redundancy features zero intervention time, making this solution suitable for critical infrastructures where timings are relevant, like public utilities and some large enterprises.