Abstract
Here we define a new unification algorithm for terms interpreted in semantic domains denoted by a subclass of regular types here called deterministic regular types. This reflects our intention not to handle the semantic universe as a homogeneous collection of values, but instead, to partition it in a way that is similar to data types in programming languages. We first define the new unification algorithm which is based on constraint generation and constraint solving, and then prove its main properties: termination, soundness, and completeness with respect to the semantics. Finally, we discuss how to apply this algorithm to a dynamically typed version of Prolog.

Abstract
In this study, a comparison of five topologies of active AC/DC conversion chain rectifiers is performed. The purpose of this work is to investigate the implementation of these topologies in the context of an electrolyzer system. The main purpose is to help identify the eventual advantages of active rectifiers. The studies under consideration provide an appreciation of typical three-phase two-level PWM rectifiers and three-phase Vienna rectifiers with an additional stage based on buck DC-DC conversion, for electrolyzer application. The comparative analysis is based on the following metrics: the current ripple, the power factor, the total harmonic distortion, the active switch utilization ratio, and the complexity of the solution. A Simulink model corresponding to each topology was developed to obtain the performance values for the comparison. The procedure involved conducting a steady-state analysis of each topology through simulations to obtain the main waveforms and the values for each criterion. The scores for each technical solution were then calculated. The solution based on the Vienna 3-switch rectifier presented the best results overall.

Abstract
Web accessibility features on websites are designed for individuals with disabilities that include low vision and cognitive impairments, but such features can benefit everyone. This study investigates the impact of accessibility features of the web on ambient/focal visual attention and cognitive processing in individuals without disabilities. The study involved 20 participants reading news websites with different levels of low vision and cognitive-related accessibility features while their eye movements and heart rate variability were monitored. The findings show that cognitive engagement declined over time when no accessibility enhancements were present. The study also demonstrates that enhancing cognitive accessibility leads to increased user cognitive engagement, while low vision accessibility features make websites easier to read. These findings are corroborated by self-reports and psychophysiological measures, such as eye-tracking metrics and heart rate variability. The effects from these psychophysiological measures, together with participants' self-reports, support the benefits of enhancing web accessibility features for all users. The implications for future website design are also discussed.

Abstract
The transition to circular business models poses significant challenges, particularly for Small and Medium Enterprises (SMEs). These challenges arise from different perspectives. Strategic alignment and technological barriers are just two of them. This paper aims to explore how Industry 4.0 technologies and Enterprise Architectures can facilitate the implementation of circular business models. By analyzing their role in overcoming key obstacles, the study explores the potential of these technologies in driving sustainable business transformation. The findings indicate that while integrating circularity into business practices remains complex, Enterprise Architectures, through the adoption of Industry 4.0 technologies, can mitigate some barriers. Ultimately, the synergy between technological innovation and circular business models can accelerate the shift towards sustainability.

Abstract
Kleene algebras (KA) and Kleene algebras with tests (KAT) provide an algebraic framework to capture the behavior of conventional programming constructs. This paper explores a broader understanding of these structures, in order to enable the expression of programs and tests yielding vague or inconsistent outcomes. Within this context, we introduce the concept of a paraconsistent Kleene Algebra with tests (PKAT), capable of capturing vague and contradictory computations. Finally, to establish the semantics of such a structure, we introduce two algebras, SetP(T) and RelP(K,T), parametric on a class of twisted structures K and T. We believe this sort of structures, for their huge flexibility, have an interesting application potential.

Abstract
The main aim of this chapter is to explore the role of social media in the internationalization of business-to-business (B2B) companies, addressing a remaining gap in the literature. It includes a qualitative study, where data from semi-structured interviews was subject to thematic content analysis. The study found that social media acts as a facilitator of internationalization in the B2B setting. While social media alone does not determine the success of internationalization efforts, it has become an essential tool for firms seeking to engage with global markets and maintain a competitive edge. The study provides relevant insights for managers, recommending that businesses should track social media performance to understand its impact on internationalization efforts and adjust strategies accordingly. © 2025 Elsevier B.V., All rights reserved.