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Single-Board Computers (SBCs) were initially targeted for education and small projects with low power-processing needs. However, their computational power has increased dramatically in the last few years, and they are now used in more advanced developments. In this paper, a study of the feasibility of using ARM-based SBCs as hypervisors is done. The authors selected the Raspberry Pi 4 Model B and the ODROID-N2+ and assessed them as virtualization servers, when running up to four VMs simultaneously, with the Linux de facto hypervisor (KVM). The tests performed in this work include: reading and writing throughputs in different types of storage media, processing power assessment, memory performance, timed compilations of open-source software, and performance of encryption algorithms. The results of the experiments showed that the amount of memory available in these SBCs is a determinant factor about the maximum number of VMs that can be executed simultaneously. The performance of the ODROID-N2+ exceeded the Raspberry Pi 4 Model B. However, the community support received by the latter is huge compared to the one of the former, and this can be a game changer when selecting a viable platform.

Modbus is the de facto standard communication protocol for the industrial world. It was initially designed to be used in serial communications (Modbus RTU/ASCII). However, not long ago, it was adapted to TCP due to the increasing popularity of the TCP/IP stack. Since it was originally designed for controlled serial lines, Modbus does not have any security features. In this paper, we wrote several benchmarks to evaluate the performance of networking devices that run Modbus TCP. Parameters reported by our benchmarks include: (1) response time for Modbus requests, (2) maximum number of requests successfully handled by Modbus devices in a specific amount of time, and (3) monitoring of Modbus devices when suffering a Distributed Denial of Service attack. Due to the growing adoption of IoT technologies, we also selected two widely known and inexpensive development boards (ESP8266 and Raspberry Pi 3 B+/OpenPLC) to realize a performance evaluation of Modbus TCP.

Vehicular Ad hoc Networks (VANETs) have gained considerable attention in the past few years due to their promising applicability in relation to the Intelligent Transportation Systems (ITSs). This emerging new technology will provide timely information to develop adaptive traffic light control systems that will allow a significant optimization of the vehicular traffic flow. In this paper, we introduce a novel algorithm for counting vehicles stopped at a traffic light using VANET technology. The algorithm is based on the idea of the propagation of a count request message from the RSU (originating unit) toward the vehicles that are at the end of the waiting line, and the propagation of a response message (with the number of vehicles counted) in the opposite direction, that is, from the vehicles at the end of the line toward the RSU. For this, our algorithm uses BEACON messages periodically to exchange the necessary information between any two 1-hop neighbors. Using the data received from BEACON messages, each vehicle can maintain its own neighbors list. To validate and evaluate the performance of our proposal, we use Veins (Vehicle in Network Simulation) and TraCI (Traffic Control Interface). The former is a framework that ties together a network simulator (OMNeT++) with a road traffic simulator (SUMO), and the latter is an API for the communications between both simulators by providing TCP connections between each other. The results of the simulations performed in different scenarios are encouraging since they indicate that the proposed algorithm efficiently computes a number of vehicles very close to the real one, using a few control messages.

In this paper, we survey network simulators and/or emulators with support for wireless networks. We selected six tools, OMNeT++/INET, ns-3, Packet Tracer, Mininet-WiFi, CORE and Komondor, and further investigate them in regards to their potential use in higher education. These simulators/emulators are readily available and have support for wireless networks in one form or another. The goal of the paper is to help instructors in choosing adequate software to assist online teaching of courses related to wireless networks, including laboratories, using virtual devices, with a minimum investment.

Integrating emerging technologies into current systems is critical to enhance the human quality of life. In the field of transportation, the automobile is the predominant locomotion method used by people. Even though new vehicular safety systems have been integrated into vehicles, road accidents are still one of the major reasons for death worldwide. In general, Vulnerable Road Users (VRUs) that share roads with vehicles have second priority in safety systems for the Intelligent Transportation System, since they are mostly focused on avoiding collision between vehicles. However, VRUs do represent a very significant percent of the victims of road accidents. In this paper, we propose a solution where the integration of current and future technologies to the vehicular safety system is a key factor, so that roads will be a better place for all the actors (people, animals, and vehicles) that transit on them. In order to protect VRUs and animals on or nearby the roads, a collision-avoidance system with two levels is proposed. The idea is to have a flexible solution that will integrate any current technology and new technologies as they appear. Warning information will be delivered in real-time about people, other living beings, vehicles, and obstacles when a possible collision is detected. On the lower level, on-board computers can address imminent threats thanks to the access to lightweight quality information consisting of data samples shared by vehicles, persons, and animals that join the common platform. In the upper level, additional support based on pre-processed information coming as a service from the Cloud will also assist any decision. With all this information, a vehicle will be in the capacity of taking instant safety decisions, in real-time, and without overloading its local computational resources.

With the introduction of the Digital Literacy and Computer Science (DLCS) education standards, there is a need for Alabama teachers at all grade levels to be equipped with software tools that can be used to bolster students' learning of content standards as well as the knowledge and resources to quickly begin leveraging them in the classroom. The purpose of this paper is to examine software solutions that can be adapted for teaching within the scope of DLCS content standards based on, among other characteristics, cost, supplemental resources, verbal and coding language options, and accessibility. It was found that free and open-source tools with a wide range of additional resources exist in abundance. However, these tools generally lack accessibility, either for English as a second language (ESL) or blind/visually impaired users. Furthermore, integration with learning management systems (LMS) is very limited, but in some instances, this is a limitation of the LMS rather than the software, and file submission for assignments ensures these tools are still viable for instructors and schools that rely on an LMS in their classes.