Svetoslav Enkov

Background: Despite the widespread adoption of IoT and LTE technologies in logistics, empirical research quantifying the economic impact of preventing operational errors remains scarce. Methods: This paper presents a case study of a Bulgarian transport company with over 800 tractors and 650 trailers, awarded “Transport Company of the Year 2025” at the Plovdiv Business Awards. An architecture combining BLE sensors, LTE trackers, and two-way integration between the TMS and the Kitin GPS platform was deployed. Using a mixed-methods approach (quantitative KPIs and qualitative process analysis), we measured the effect on annual excess mileage, trailer swap registration time, and error frequency. Results: The results show a 90% reduction in excess mileage (from 10,000 km to 1000 km), a 99.9% faster swap registration time, and a 90% reduction in errors. Annual savings amount to €19,750, with an investment payback period of 13–14 months (334% ROI over 5 years). Conclusions: The scientific contribution is the empirical demonstration that error prevention (correct trailer attachment) dominates asset tracking as a source of value. Theoretical and practical recommendations for fleet managers are presented.

In recent years, there is rise in various human-computer interaction interfaces and automatic text translation services and frameworks. In this paper, we conduc

The article addresses the problem of accessibility of dynamic web content that is created when developing web pages and services. It discusses basic issues about the accessibility of digital objects and web page content. The aim of the article is to present a method for designing accessibility in the creation of dynamic web content in websites of Paisii Hilendarski Plovdiv University. The developed method is presented through the life cycle of its model, which is applied in parallel with the implementation of a software process in the renewal of the web infrastructure of the university. The method is built on standards, principles, guidelines, accessibility criteria, and techniques for creating and validating web content of the Web Accessibility Initiative. The main standards to which the method adheres are the Web Content Accessibility Guidelines and the Technical Specifications for Accessible Rich Internet Applications. It has been tested in the design and implementation of part of the web content of the web infrastructure of the university created after 2020, which is accessible through the main domain https://uni-plovdiv.bg and many of its sub-domains.

In this paper we investigate two-dimensional nonlinear Fredholm fuzzy functional integral equation (2D-NFFFIE). Our aim is to provide an efficient iterative method of successive approximations by optimal quadrature rule for classes of fuzzy number-valued functions of Lipschitz type for two-dimensional case to approximate the solution. We prove the convergence and numerical stability of the presented method with respect to the choice of the first iteration. Finally, some numerical experiment confirm the theoretical results and illustrate the accuracy of the proposed method.

In this paper, we propose an efficient iterative method to solve two-dimensional nonlinear Hammerstein fuzzy functional integral equations based on fuzzy Haar wavelets. We prove the convergence of the method by Banach’s fixed point theorem and investigate the numerical stability of the presented method with respect to the choice of the first iteration. Finally, some numerical experiment confirm the theoretical results and illustrate the accuracy of the proposed method.

In this work we investigate nonlinear Hammerstein fuzzy functional integral equation. Our aim is to provide an efficient iterative method of successive approximations by optimal quadrature formula for classes of fuzzy number-valued functions of Lipschitz type to approximate the solution. We prove the convergence of the method by Banach’s fixed point theorem and investigate the numerical stability of the presented method with respect to the choice of the first iteration. Finally, illustrative numerical experiment demonstrate the accuracy and the convergence of the proposed method.