Lucian Mandache

The growing complexity of electrical systems requires advanced analysis tools to optimize the design time and resources. While many circuit simulators exist, they often lack the flexibility needed for real-world applications. In this context, our paper develops practical approaches to building Thévenin and Norton equivalent diagrams by means of modern software facilities which overpass the capabilities of common commercial circuit simulators. They use the symbolic computation of two simulation tools developed by our research team. The proposed algorithms are not limited by the operation behavior of the analyzed systems, being usable in both DC and AC circuits, as well as in transients. The developed method facilitates and speeds up the complex analyses required by repeated simulations specific to the modern design process. Three case studies are discussed to prove the efficiency of the developed algorithms. They cover real DC and AC applications, respectively. The results obtained using the Thévenin and Norton equivalent diagrams were validated through analyses of the initial systems.

As the EU strives to achieve its climate goals, it is becoming increasingly crucial to understand the complex relationships between economic activity, energy consumption, and carbon emissions. In this context, our paper aims to investigate the correlation between carbon emissions, energy consumption, and economic development. To fulfill our aim, we have used Eurostat and OECD data for the EU-27 member states for a period of 13 years (2010–2022), using a linear regression as the main analysis method. Our results have shown that there is a strong correlation between demand-based and production-based CO₂ emissions as well as between production-based CO₂ emissions and final energy consumption, while at the same time, our findings have shown that there is no direct correlation between energy consumption and economic development, aligning our study with the neutrality hypothesis of the energy growth nexus. This paper expands the ongoing discussion on sustainable development and climate change mitigation by conducting a thorough analysis of the EU-27 countries over a span of thirteen years. The results emphasize the need for integrated strategies that address both production and consumption emissions, emphasize the vital role of energy efficiency, and raise questions about the effectiveness of increasing energy consumption to enhance economic productivity or CO₂ efficiency.

Although risks are present in any organisation and the importance of their study is obvious, the authors find that risk analysis is an area still in its infancy, as reflected in the small number of existing publications on this topic. Human resources tend to understand risk in an elementary way. The ability of human resources to perceive risk is the ability and competence to identify a potential threat that does not always appear. Aim: The aim of the this chapter was to provide additional knowledge on human resource competencies, in order to avoid the emergence and spread of risks at the organisational and cyber level. Methodology: The authors used the quantitative–comparative analysis, by presenting all the details regarding the competencies of the human resource in order to manage the risks at organisational and cybernetic level. Findings: The findings of this chapter show that the compulsory competencies of the human resource influence both the general competencies and the special competencies: information technology and communications, security ethics and economic ones. These, in turn, can improve or diminish cyber security competencies by almost 50%. Originality of the Study: This study is highlighted by results obtained from the analysis of the capacity of human resources, to integrate theoretical knowledge and practical competencies on the perception of cyber risk. Of particular importance for this research are the analysis of data and the interpretation of results on human resources competencies. In this sense, throughout the chapter are assessed the skills of human resources, necessary for the management of cyber risks at the organisational level. In terms of future research implications, it could be important research to identify a method of assessing the competencies acquired by human resources applied from the perspective of cyber risk.

The pandemic crisis has meant a challenge for SMEs and a factor that can change the way of doing business. The current paper analyses the correlations between financial resources, turnover, sustainability, and digital technologies and how these components can be adapted to changes in the economy triggered by the pandemic crisis in the structure of activities carried out by SMEs. Resting on the importance of integrating the innovative, digital component to the activities of SMEs, in close connection with the financial resources component, a multicriteria research model for business has been developed, assessing the correlations between key variables and their influence on European SMEs. In order to fully define the concepts envisaged and to emphasise these correlations, multiple linear regression, clustering techniques, and correlation analysis were used. In the end, the proposed solution provided a common language through which companies can evaluate traditional processes and bring together the research components into business activities.

In terms of sustainability, traditional disclosure does not provide the necessary information to all stakeholders, mainly addressing the company’s shareholders’ expectations. As a result, organisations need to disclose more non-financial information, which implies social and environmental issues. Many organisations currently provide sustainability reports in addition to the annual management reports containing financial and economic data. Several studies have focused on adopting practices and tools in the sustainability area and their overlap with traditional managerial techniques and tools. Nevertheless, integration involves a harmonising process, compatibility and alignment between different management practices. This study aims to assess the impact that the inclusion of sustainable reporting practices in corporate management reports has on economic performance, and to support filling the gap in the specific literature by proposing an integrated reporting model achieved through a harmonising process, compatibility and alignment.

Some new models for nonlinear capacitors and nonlinear inductors built with SPICE-like element primitives are presentedhere. They have the advantage that they can be used for simulation in SPICE of those circuits which contain nonlinearcapacitors controlled either in voltage or in charge, and nonlinear inductors controlled either in current or in flux. TheseSPICE-like models contain current sources whose controlling variables are charge time-derivative and sources whosecontrolling variables are flux time-derivative. For validation, the models are included in nonlinear circuits; their behavior isstudied by simulation using two different simulators and the results are compared.

The paper is focused on a new and accurate design tool which uses a high precision model for nonlinear lossy ferromagnetic cores. It can be easily included in a time-domain circuit simulator, like SPICE, being suitable to simulate any saturable inductor operating in any distorting regime at low or medium frequencies such cases are found in power electronics applications. The model uses as entry data the geometric dimensions of the magnetic core including air-gaps, the magnetic material properties given by the manufacturer data sheet and the winding constructive parameters. Therefore, the correspondence with the real device is realistic and undoubted. The proposed modeling technique takes its mathematical root from the Maxwell's theory. The simulation results give time-domain flux distribution in the magnetic core, the total core losses, as well as any working parameter of the circuit which includes the magnetic device. Experimental results obtained on a single phase inductor are compared with the obtained simulation results. Excellent concordance between both results is demonstrated in this paper.

The paper proposes a high efficiency and totally feasible tool that permits a rigorous study of magnetic devices, being intended firstly to the research and design activity. The method uses the most modern tools in circuit analysis, being a result of a long-time experience of authors. It deals with an accurate modeling that permits to find the distribution of magnetic fluxes everywhere in the core, at any time. The modeling is made through an equivalent electric circuit described by the same differential-algebraic equation system as the studied device in transient regime. Therefore, this circuit is analyzed using dedicated software, like SPICE. Such software has special capabilities to prevent convergence problems that usually occur in nonlinear DAE solving, as well as performing optimizations of certain parameters. The method permits not only the rigorous study of the magnetic device, but additionally a high precision analysis of complex equipments that contain magnetic devices