Nkolay Netov

Sofia University "St. Kliment Ohridski" · Faculty of Economics and Business Administration

The great interest caused by ChatGPT put emphasis not only on Large Language Models (LLM). Every single LLM must be trained on a large amount of data, and most often it is a variety of open access data sets. The accelerated deployment of pre-trained LLMs has also focused considerable interest on the topic of 'open data'. Our research describes the...

The proposed paper is devoted to presenting and analyzing a kinetic model describing the development of autoimmune disorders. The proposed model is a nonlinear system of differential equations that considers the biological activity of the interacting populations. The main characteristics of autoimmune diseases are taken into account. Preliminaries...

We live in an era of digital revolution not only in the industry, but also in the public sector. User opinion is key in e-services development. Currently the most established approaches for analyzing citizens’ opinions are surveys and personal interviews. However, governments should focus not only on developing public e-services but also on impleme...

In the past twenty years, the range of electronic services offered by educational institutions in Bulgaria has increased substantially, allowing schools, universities, and vocational training centers to offer flexible learning options. These capabilities proved essential during the COVID-19 pandemic when most educational institutions switched to on...

The accelerated implementation of information and communication technologies in all areas of public development requires in-depth studies of its effects at both national and global level. As education is one of the sectors most influenced by these trends, the need for systematic research on the application of digital technologies in the educational...

An algorithm to calculate optimal trajectories of e-buses to fulfil on-demand requests for transportation in a smart city environment is presented. Instead of solving the transportation problem once when all transportation requests are registered, we solve the transportation problem at any virtual or public station during the taxi. This approach en...

Digitalization affects all fields of the modern world including the economic, political, and social aspects of our life. Governments are also involved in this process. Considering the rapid transition towards digital e-services that we evidence since the COVID-19 outbreak, the detection and analysis of public opinion on e-government services become...

The United Nations recently published the “E-government survey 2020” with the main aim of assessing the e-government development status of all United Nations member states. The survey outlines 14 leading countries in e-government development (out of 193 member states) some of them claiming to utilize technologies as artificial intelligence (AI), bi...

The digitalization of services provided by public institutions can substantially reduce the costs of citizens’ interactions with these institutions, like travel and waiting times. It can also increase the efficiency of providing these services. Despite the benefits, Bulgaria still lags behind most European Union countries regarding the use of e-gov...

There are various approaches for development of Value at Risk (VaR) forecasting models but the final steps of a building procedure usually incorporate different validations of the models like adequacy tests and backtesting. These validations provide solid reasons to reject those models which do not pass the tests. However there are situations when...

This paper addresses the problem of solving a generalized algebraic Riccati equation with an indefinite sign of its quadratic term. We extend the approach introduced by Lanzon, Feng, Anderson and Rotkowitz (2008) for solving similar Riccati equations. We numerically investigate two types of iterative methods for computing the stabilizing solution....

This paper addresses the problem for solving a Continuous-time Riccati equation with an indefinite sign of the quadratic term. Such an equation is closely related to the so called full information H∞ control of linear time-invariant system with external disturbance. Recently, a simultaneous policy update algorithm (SPUA) for solving H∞ control prob...

We consider a set of discrete-time generalized Riccati equations that arise in quadratic optimal control of discrete-time stochastic systems subjected to both state-dependent noise and Markovian jumps. The iterative method to compute the maximal and stabilizing solution of wide class of discrete-time nonlinear equations is derived by Dragan et al....

This paper presents a data warehouse implemented on the basis of a database management system that supports operations over intuitionistic fuzzy data. The source system for the Intuitionistic Fuzzy Data Warehouse (IFDW) is a learning management system that provides university courses and is used for blended learning. To analyze the intuitionistic f...

Open innovations have become of key importance to company competitiveness in the recent years. The open innovation model enables companies to react in a swift and flexible manner to changes in business environment, despite the shortened timeframes for new products to emerge on the market and the shortened lifecycle of technologies. This paper revie...