Full wave modulation applied to 3-level FC and NPC inverters

International audienceThe multi-level converters are more and more used for high power medium voltage applications. They seem to be the best option to reduce the weight of the converter and still have high efficiency. However, they should be used with an adapted control strategy to reduce their power losses that could be high due to the used high switching frequencies and also to improve the output harmonics quality. The commonly used PWM strategy can lead to high switching losses and less output harmonic content in comparison with full wave modulation. This paper aims to explain the limits of PWM modulation for our application and the advantages of full wave modulation adapted to multilevel converters. These control strategies will be compared for 3-level FC, and 3-level NPC topologies and their effect on the converter weight and performances will be studied to find the most interesting solution regarding specific power and inverter efficiency

Enhancing pharmaceutical packaging through a technology ecosystem to facilitate the reuse of medicines and reduce medicinal waste

The idea of reusing dispensed medicines is appealing to the general public provided its benefits are illustrated, its risks minimized, and the logistics resolved. For example, medicine reuse could help reduce medicinal waste, protect the environment and improve public health. However, the associated technologies and legislation facilitating medicine reuse are generally not available. The availability of suitable technologies could arguably help shape stakeholders’ beliefs and in turn, uptake of a future medicine reuse scheme by tackling the risks and facilitating the practicalities. A literature survey is undertaken to lay down the groundwork for implementing technologies on and around pharmaceutical packaging in order to meet stakeholders’ previously expressed misgivings about medicine reuse (’stakeholder requirements’), and propose a novel ecosystem for, in effect, reusing returned medicines. Methods: A structured literature search examining the application of existing technologies on pharmaceutical packaging to enable medicine reuse was conducted and presented as a narrative review. Results: Reviewed technologies are classified according to different stakeholders’ requirements, and a novel ecosystem from a technology perspective is suggested as a solution to reusing medicines. Conclusion: Active sensing technologies applying to pharmaceutical packaging using printed electronics enlist medicines to be part of the Internet of Things network. Validating the quality and safety of returned medicines through this network seems to be the most effective way for reusing medicines and the correct application of technologies may be the key enabler

Vulnerability modelling and mitigation strategies for hybrid networks

Hybrid networks nowadays consist of traditional IT components, Internet of Things (IoT) and industrial control systems (ICS) nodes with varying characteristics, making them genuinely heterogeneous in nature. Historically evolving from traditional internet-enabled IT servers, hybrid networks allow organisations to strengthen cybersecurity, increase flexibility, improve efficiency, enhance reliability, boost remote connectivity and easy management. Though hybrid networks offer significant benefits from business and operational perspectives, this integration has increased the complexity and security challenges to all connected nodes. The IT servers of these hybrid networks are high-budget devices with tremendous processing power and significant storage capacity. In contrast, IoT nodes are low-cost devices with limited processing power and capacity. In addition, the ICS nodes are programmed for dedicated functions with the least interference. The available cybersecurity solutions for hybrid networks are either for specific node types or address particular weaknesses. Due to these distinct characteristics, these solutions may place other nodes in vulnerable positions. This study addresses this gap by proposing a comprehensive vulnerability modelling and mitigation strategy. This proposed solution equally applies to each node type of hybrid network while considering their unique characteristics. For this purpose, the industry-wide adoption of the Common Vulnerability Scoring System (CVSS) has been extended to embed the distinct characteristics of each node type in a hybrid network. To embed IoT features, the ‘attack vectors’ and ‘attack complexity vectors’ are modified and another metric “human safety index”, is integrated in the ‘Base metric group’ of CVSS. In addition, the ICS related characteristics are included in the ‘Environmental metric group’ of CVSS. This metric group is further enhanced to reflect the node resilience capabilities when evaluating the vulnerability score. The resilience of a node is evaluated by analysing the complex relationship of numerous contributing cyber security factors and practices. The evolved CVSSR-IoT-ICS framework proposed in the thesis measures the given vulnerabilities by adopting the unique dynamics of each node. These vulnerability scores are then mapped in the attack tree to reveal the critical nodes and shortest path to the target node. The mitigating strategy framework suggests the most efficient mitigation strategy to counter vulnerabilities by examining the node’s functionality, its locality, centrality, criticality, cascading impacts, available resources, and performance thresholds. Various case studies were conducted to analyse and evaluate our proposed vulnerability modelling and mitigation strategies on realistic supply chain systems. These analyses and evaluations confirm that the proposed solutions are highly effective for modelling the vulnerabilities while the mitigation strategies reduce the risks in dynamic and resource-constrained environments. The unified vulnerability modelling of hybrid networks minimises ambiguities, reduces complexities and identifies hidden deficiencies. It also improves system reliability and performance of heterogeneous networks while at the same time gaining acceptance for a universal vulnerability modelling framework across the cyber industry. The contributions have been published in reputable journals and conferences.Doctor of Philosoph

Machine learning-based agoraphilic navigation algorithm for use in dynamic environments with a moving goal

This paper presents a novel development of a new machine learning-based control system for the Agoraphilic (free-space attraction) concept of navigating robots in unknown dynamic environments with a moving goal. Furthermore, this paper presents a new methodology to generate training and testing datasets to develop a machine learning-based module to improve the performances of Agoraphilic algorithms. The new algorithm presented in this paper utilises the free-space attraction (Agoraphilic) concept to safely navigate a mobile robot in a dynamically cluttered environment with a moving goal. The algorithm uses tracking and prediction strategies to estimate the position and velocity vectors of detected moving obstacles and the goal. This predictive methodology enables the algorithm to identify and incorporate potential future growing free-space passages towards the moving goal. This is supported by the new machine learning-based controller designed specifically to efficiently account for the high uncertainties inherent in the robot’s operational environment with a moving goal at a reduced computational cost. This paper also includes comparative and experimental results to demonstrate the improvements of the algorithm after introducing the machine learning technique. The presented experiments demonstrated the success of the algorithm in navigating robots in dynamic environments with the challenge of a moving goal

Low Latency Reliable Data Sharing Mechanism for UAV Swarm Missions

The use of Unmanned Aerial Vehicle (UAV) swarms is increasing in many commercial applications as well as military applications (such as reconnaissance missions, search and rescue missions). Autonomous UAV swarm systems rely on multi-node interhost communication, which is used in coordination for complex tasks. Reliability and low latency in data transfer play an important role in the maintenance of UAV coordination for these tasks. In these applications, the control of UAVs is performed by autonomous software and any failure in data reception may have catastrophic consequences. On the other hand, there are lots of factors that affect communication link performance such as path loss, interference, etc. in communication technology (WIFI, 5G, etc.), transport layer protocol, network topology, and so on. Therefore, the necessity of reliable and low latency data sharing mechanisms among UAVs comes into prominence gradually. This paper examines available middleware solutions, transport layer protocols, and data serialization formats. Based on evaluation results, this research proposes a middleware concept for mobile wireless networks like UAV swarm systems

Hybrid sensorless control of PMSM in full speed range using HFI and back-EMF

The permanent magnet synchronous motors (PMSM) are more and more used because of their high performance compared with other AC motors. The present paper proposes a hybrid controller which consists of a high frequency injection estimator and a back-electromotive-force observer in full speed range for the sensorless control of PMSM. The aim objective of the study to prevent speed overshot in startup time of the motor and provides a better dynamic response in transient and permanent states using this structure. A hybrid algorithm is applied to realize a smooth transition from low to high speed. At standstill and very low speed region, HF injection technique is used to detect the rotor initial position. In this first step study, the position estimation is derived from a HF current injection by using only one filter. When the rotor speed goes up to a certain value where back-EMF can provide adequate information, a back-EMF observer will dominate. Thanks to this structure, the mechanical sensor can be engaged using the best estimates and the developed control method is fast, simple, and flexible. The effectiveness, superiority, and performance of the proposed control method and extensive simulation results are provided on a 1 kW permanent magnet synchronous motor drive, demonstrating the expected performances

A Novel Ensemble Model Using Learning Classifiers to Enhance Malware Detection for Cyber Security Systems

In the Internet of Things arena, smart gadgets are employed to offer quick and dependable access to services. IoT technology has the ability to recognize extensive information, provide information reliably, and process that information intelligently. Data networks, controllers, and sensors are increasingly used in industrial systems nowadays. Attacks have increased as a result of the growth in connected systems and the technologies they employ. These attacks may interrupt international business and result in significant financial losses. Utilizing a variety of methods, including deep learning (DL) and machine learning (ML), cyber assaults have been discovered. In this research, we provide an ensemble staking approach to efficiently and quickly detect cyber-attacks in the IoT. The NSL, credit card, and UNSW information bases were the three separate datasets used for the experiments. The suggested novel combinations of ensemble classifiers are done better than the other individual classifiers from the base model. Additionally, based on the test outcomes, it could be concluded that all tree and bagging-based combinations performed admirably and that, especially when their corresponding hyperparameters are set properly, differences in performance across methods are not significant statistically. Additionally, compared to other comparable PE (Portable Executable) malware detectors that were published recently, the suggested tree-based ensemble approaches outperformed them

An ANN-based temperature controller for a plastic injection moulding system

This paper proposes an approach to an ANN-based temperature controller design for a plastic injection moulding system. This design approach is applied to the development of a controller based on a combination of a classical ANN and integrator. The controller provides a fast temperature response and zero steady-state error for three typical heaters (bar, nozzle, and cartridge) for a plastic moulding system. The simulation results in Matlab Simulink software and in comparison to an industrial PID regulator have shown the advantages of the controller, such as significantly less overshoot and faster transient (compared to PID with autotuning) for all examined heaters. In order to verify the proposed approach, the designed ANN controller was implemented and tested using an experimental setup based on an STM32 board