On 1 January 2001, the IEC 61000-3-2 regulation became effective. Since then, mitigating current harmonics has been essential to ensure that electronic equipment connected to single-phase power distribution lines conforms to electromagnetic compatibility directives. Today, high-quality rectification, commonly known as power factor correction (PFC), is a well-established technique widely adopted by the industry for powering various devices from the ac line. The topic has been studied by academia and industry since the mid-1980s; thus, an enormous amount of research has been published and countless solutions have been proposed since then. However, only a few of those solutions have encountered wide industrial usage. So, it is not the authors’ intention to provide a comprehensive review, but to take stock of the most used PFC techniques from an industry perspective. This paper will review the power factor theory with non-sinusoidal currents, the practical and regulatory aspects of using PFC, and the most common industry solutions for power factor correction in equipment operated from the single-phase, public, low-voltage supply system, with a special focus on boost PFC pre-regulators, their control methods, design procedures, and issues.

Enterprise development is a multifaceted and strategic endeavor that serves as the cornerstone of an organization’s long-term success and sustainability. It represents not merely growth or expansion but a comprehensive transformation that enhances a company’s capabilities, market presence, and internal processes. This development is driven by a deliberate and systematic effort to improve performance across all areas of business activity, aligning with stakeholders’ aspirations and organizational goals. In this context, enterprise development encompasses the strategic management of the organization’s trajectory through effective planning, execution, and evaluation of development initiatives. It demands an adaptive and responsive approach to the rapidly evolving business environment, where challenges and opportunities arise constantly. This requires leveraging modern management practices and analytical tools to integrate various components of the company’s operations, including human resources, finances, technology, and marketing, fostering a cohesive and dynamic growth strategy. The essence of enterprise development lies in the organization’s ability to remain agile—capable of swiftly responding to market changes while proactively seeking and capitalizing on new opportunities. This involves not only addressing external competitive pressures but also mitigating internal risks, ensuring that the enterprise is well-positioned to navigate and thrive in complex environments. The issues related to the phenomenon of enterprise development refer to the geographical area of the so-called Global North. The aim of this entry is to explore and critically analyze contemporary strategies and models that facilitate effective management and acceleration of enterprise growth, providing a framework for organizations aiming to achieve excellence and innovation in the modern economic landscape.

The observation of randomness patterns serves as guidance for the craft of probabilistic modelling. The most used count models—Binomial, Poisson, Negative Binomial—are the discrete Morris’ natural exponential families whose variance is at most quadratic on the mean, and the solutions of Katz–Panjer recurrence relation, aside from being members of the generalised power series and hypergeometric distribution families, and this accounts for their many advantageous characteristics. Some other basic count models are also described, as well as models with less obvious but useful randomness patterns in connection with maximum entropy characterisations, such as Zipf and Good models. Simple tools, such as truncation, thinning, or parameter randomisation, are straightforward ways of constructing other count models.