This paper presents an enhanced fault-tolerant architecture for industrial Networked Control Systems (NCS) that simultaneously supports supervision video transmission and maintains strict real-time constraints. Building upon previous work that optimized video and control data flows through static traffic management techniques, this study introduces approaches to address fault tolerance and scalability challenges. First, supervision video enhanced quality operating up to the standard 50 frames per second (fps) was tested. Second the use of Field Programmable Gate Array (FPGA) resources embedded within the core network switch to handle controller fault recovery locally is proposed and tested. The use of this FPGA-enhanced architecture effectively isolates control and video traffic, ensuring real-time responsiveness even with supervisory cameras operating at high frame rates. Simulation results confirm maximum delays in faulty scenarios, well within the real-time requirements. The proposed solutions demonstrate possible scalable methods for integrating fault tolerance and high-quality video supervision in modern industrial NCS, with the FPGA-based design offering latency improvements of 7.58% over previously studied designs.

Advanced Driver Assistance Systems (ADAS) are being thoroughly researched nowadays especially in the field of autonomous vehicles. However, motorcycles and Advanced Rider Assistance Systems (ARAS) have not yet received the same level of attention. This paper is an attempt to address some of the problems encountered by motorcycle riders in urban areas, namely obstacle detection and alerting the rider if vehicles behind him/her are travelling at an illegally high speed. The proposed system uses a fusion algorithm that combines readings from two LiDAR sensors, one on the motorcycle and the other in the rider’s helmet. Additionally, two cameras are fixed on the motorcycle, one facing forward and the other facing backwards. YOLO, Ultra-Fast Lane Detection network and sensor front/rear sensor fusion are then used to reach a reliable decision to alert the rider of a potential danger and to advise him/her regarding the most appropriate maneuver to avoid the danger.

Fault-Tolerant (FT) architectures are often used in the context of Industrial Automation, especially in safety-critical systems. Coverage is a very important parameter; it measures the ability of these systems to detect and recover from expected failures. This paper investigates the effect of changes in the value of the Coverage parameter on the steady state availability of several commonly used FT architectures, namely Triple Modular Redundancy (TMR), Sift-Out and Reconfigurable Duplication. When comparing TMR and Sift-Out, it is found that, at relatively low values of coverage, adding redundancy will reduce availability and increase downtime; this is a counter intuitive result. For Reconfigurable Duplication, it is found that, at low Mean Time To Repair (MTTR), the effect of small changes in coverage has little effect on architecture availability. Hence, it is preferable to invest in the quality of the system's redundant modules instead of the quality of the error detection and recovery mechanisms. In contrast, at higher MTTRs, a small increase in the coverage affects availability; hence, investing in the quality of error detection will lower downtime and decrease profit loss.

A fault-tolerant Wi-Fi-based architecture for a Modular Prosthetic Limb (MPL) is studied in this paper. The focus is first on the actuators' controllers in the arm and a design technique is developed to reduce the maintenance costs as well as the cost of the arm's supervisor module without compromising its reliability. This technique can also be used as an analysis tool. Another contribution of this paper is related to motor redundancy. It is shown (using Petri Nets) how to increase their lifetime while reducing the cost of the added redundancy.

This paper proposes a system for intelligent energy management in electric vehicles. This system incorporates parameters relating to driving style of the car, trip information and battery states. The driving cycle classification subsystem is implemented in different scenarios, and the results of power, performance and utilization are reported. Finally, a performability analysis, utilizing the implementation scenarios for increasing the system reliability, is presented.

Vehicle-to-Everything (V2X) technology plays a critical role in maintaining road safety, avoiding accidents and controlling traffic flow. As self driving cars are expected to take over the roads, this paper discusses the intermediate phase in which manned and unmanned cars coexist. A heterogeneous network architecture that simultaneously serves manned and unmanned cars' different requirements in a suburban area is proposed and simulated using Riverbed Modeler. The feasibility of this architecture is examined in three different scenarios: Normal operation, congestion in both directions and Road Side Units (RSU) failure. In normal operation mode, traffic data is sent through Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure/Infrastructure-to-Vehicle (V2I/I2V or to RSU) using IEEE 802.11p and infotainment information is communicated as V2I/I2V using Long Term Evolution (LTE). A special case is highlighted and tested, in which congestion is in both directions. In such situation, data needs to be relayed to the nearest RSU using multi-hop communication. A fault-tolerant model is also proposed and analyzed in case of failure of RSU. The performance metrics are end-to-end delay, LTE response time, handover delay and packet loss ratio. The architecture proves its suitability by satisfying traffic control real time application requirements.

The continued increase in several mobile applications forces to replace existing limited spectrum indoor radio‐frequency wireless connections with high‐speed ones. Visible light communication (VLC) is a promising license free indoor wireless technology that could offer high‐speed connections. However, both co‐channel interference (CCI) from more neighbour transmitters and inter‐symbol interferences (ISI) from multipath reflections limit the performance of VLC downlink channel. In this study, a constraint field of view angular diversity receiver (CFOV‐ADR) is proposed to mitigate these limitations. By optimising the photodetector's (PD) field of view (FOV) angle, the line of sight CCI could be totally eliminated and the ISI could be significantly reduced. The optimal range for FOV angle is calculated in a typical indoor scenario. Furthermore, the zero‐forcing (ZF) algorithm is applied to the conventional ADR (ADR‐ZF) which can significantly eliminate the ISI components. The received optical signal‐to‐interference‐plus‐noise ratio (SINR) is tested at various room positions. The simulation results show that the proposed CFOV‐ADR can achieve higher SINR performance than single receiver, conventional ADR, and ADR‐ZF at all positions and orientations.

Backhaul technologies include traditional technologies such as Radio Frequency (RF) or Optical Fibers (OF) backhauls and include new technologies such as Free Space Optical (FSO) or hybrid RF/FSO backhauls. This paper aims to improve the network connectivity by adding a limited number of OF links along with the wireless connections of RF, FSO or hybrid RF/FSO backhaul links between the small cells. The connectivity is improved while satisfying the minimum data rate (R) constraint and taking into consideration the cost and reliability of different links. We address the problem of maximizing the algebraic connectivity due to inserting different types of backhaul technologies. The Fiedler value, which is the algebraic connectivity of a graph, is used to measure the connectivity of the network. We show that under realistic cost assumption and linear relaxation, the problem is a convex optimization problem. Simulation results show that, using the proposed solution, a high connectivity can be achieved.

Fault-tolerance is becoming an increasingly crucial aspect of the design of Networked Control Systems (NCSs) in order to mitigate system downtime. However, the introduction of fault-tolerance is typically associated with significant traffic overhead. In this paper, an optimization to an Ethernet-based network fabric fault-tolerant NCS is proposed. The proposed optimization halves the amount of overhead traffic necessary for fault-tolerance while maintaining the same level of robustness. Moreover, based on the same optimization methodology, an expanded model with two in-line cells is presented and subsequently tested. The expanded two-cell model is designed to provide controller-level in addition to fabric-level fault-tolerance. Simulations using OPNET followed the traffic analysis, and proved the models to be fully reliable in the case of a single failure at a time, for both the single-cell model and the expanded two-cell network.

Cognitive radios emerged as a solution to spectrum scarcity problem. The integration of cognitive radios and wireless sensor networks enables a new paradigm of communication, in which the sensor nodes can avoid heavily‐crowded transmission bands by tuning their transmission parameters to less‐crowded bands. The authors consider the problem of spectrum assignment for cognitive radio sensor network (CRSN) under coverage, interference, minimum data rate and power budget constraints. A mixed‐integer non‐linear programming problem formulation that addresses optimal power allocation, channel selection and node scheduling is presented. Following a practical assumption, that any CRSN node can only access one channel for its transmission with the CRSN base station, the problem is transformed to a binary linear programming (BLP) problem. Using the relaxation techniques, the problem is transformed to a linear programming problem that is solvable in polynomial time, and has the same optimal solution of the BLP problem. Hence, the minimum power algorithm that achieves the optimal solution of our problem is proposed. To further reduce the complexity of the solution, three heuristic lower‐complexity algorithms are proposed to solve the problem: random, greedy and two‐stage (decoupled) algorithms.

Applying multiple redundant and diverse communication channels is an established method to achieve an improved overall communication channel. When applied for packet-based data transmission over channels with strongly nondeterministic behaviour due to environmental influence, such as Wireless Communications, timing performance can be greatly improved by this approach. The central element in such a system is the so called “Combiner” on the receiving side. In this work, a new specific type named “Timing Combiner” is described. The Parallel Redundancy Protocol (PRP) according to IEC 62439-3 realizes such a Timing Combiner on the Ethernet level. In this work, an OPNET simulation model is created and analysed for its performance characteristics. Also a quantitative analysis of the effect of different interference models in an industrial environment is presented.

Networked Control Systems (NCS) are widely used in industrial applications. Ethernet has recently been used as the communication protocol in NCS. Since overcoming faults is crucial in control systems, fault-tolerance in NCS is being extensively investigated. This paper focuses on the fault-tolerance aspect of Ethernet-based NCS at the network fabric level. It proposes a novel architecture that achieves successful recovery from any single link or switch failure. The model was also tested and proved to be fault-tolerant for some multiple failures.

Wireless Sensor Networks (WSN) has become an attractive field for research due to the increasing number of applications. This paper uses a WSN to monitor Electromagnetic Pollution and report any violations in power levels. An event-by-event simulator is developed to calculate network lifetime and study important factors affecting it. One of these factors is determining the energy threshold of the Network Master. Different node distributions are investigated. It is found that the 10×10 star results in a 77% increase in lifetime in comparison with the Homogeneous Density distribution.

Wireless sensor networks is a voracious field for research, especially after the great advances in MEMS based sensors. In this paper, environmental monitoring applications are considered where data may be continuously reported with the possibility of urgent alarming if necessary. Hierarchical architecture of the network is assumed in order to overcome the problem of energy constrained sensors. Two algorithms are proposed with the purpose of network lifetime elongation and the maximization of the use of the available energy. The first algorithm is a modification for LEACH-C to enhance its performance. It results in a 25% longer lifetime. The second algorithm is an energy efficient method to ensure full coverage of the network as long as sensors are still working. This achieves 32% longer lifetime than LEACH-C.

Ubiquitous computing is increasingly introduced in our daily life. An emerging application is environmental monitoring in urban areas. Data gathering in such wireless sensor networks can be performed by using uncontrolled mobile sinks besides the fixed sinks in order to reduce the transmission energy. This method can be highly inefficient as the notification of presence by the mobile sink is not guaranteed. An efficient hybrid method for message relaying and load balancing is proposed in low mobility wireless sensor networks. The system uses either a single hop transmission to a nearby mobile sink or a multi-hop transmission to a far-away fixed node depending on the predicted sink mobility pattern. Taking a mathematical approach, the system parameters are adjusted so that all the sensor nodes dissipate the same amount of energy. Consequently, the problem of losing connectivity due to the fast power drainage of the closest node to the fixed sink is resolved. Numerical results showed that the system lifetime outperforms classical methods of message gathering.

In this paper, a pyramid control hierarchy is proposed. It is based on the presence of a supervisor controller on top of separate controller nodes. A simulation study is conducted to test the functionality of the system. The proposed model is an enhancement of machine modeled in form of networked control systems (NCS). Two models are tested: one supervisor/two sub-controllers, one supervisor/three sub-controllers. All possible combinations of supervisor-controller intercommunication are tested. Also, all supervisor/controller inter-changeability possibilities are taken into consideration. Results are illustrated and discussed. Recommendations are drawn out. All machine models of this study are built using switched gigabit Ethernet in star topology