Serhiy Lyeonov

A significant size of the shadow economy is a threat to the sustainable functioning of a country’s economy, its ability to finance economic and social programs. The paper studies the influence of the shadow economy on the macro-financial stability of the EU countries. The dependence between macro-financial stability and the size of the shadow economy was estimated using the quadrocentric (considering the four channels of the shadow economy) recursive (takes into account direct and inverse relationships between them) model. Dependence between indicators was analyzed using Euler’s methods, Calvo’s and Dixit Stiglitz’s principles, Taylor’s and Smets-Wouters’ function. It has been proved that shadow economy channels affect the macro-financial stability almost equally (an increase in the size of the shadow economy in Slovenia by 1% leads to a decrease in macro-financial stability by 0.562% for tax, 0.56% for investment, 0.572 for institutional, and 0.444 for social channels). At the same time, the growth in the volume of shadow transactions through one channel forms an impetus for the increasing intensity of use of the remaining channels to hide income. With the help of the payment matrix, the optimal level of drivers of shadow economy by which the targeted value of the level of macro-financial stability is achieved was determined. It was concluded that ensuring good governance in the direction of preventing shadow schemes of capital withdrawal should be carried out in terms of institutional, tax, social, and investment channels of the shadow economy.

Acknowledgment
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-16-0602.

Changes in the logistics of energy resources and their potential shortage are causing a review of the EU energy policy. The energy sector significantly affects the progress toward achieving climate policy goals due to significt greenhouse gas emissions. The REPowerEU plan, implemented in the EU27 to overcome the energy crisis, requires new forecasts of greenhouse gas emissions due to a change in European energy policy.
This paper aims to examine the consequences of the management of the energy crisis caused by Russia’s invasion of Ukraine on EU climate policy. This study focuses on forecasting greenhouse gas emissions in the EU until 2030 and uses the Seasonal ARIMA model based on quarterly time series in the EU27.
Depending on energy management and changes in energy policy to overcome the energy crisis, a positive or negative scenario for greenhouse gas emissions may occur. An important parameter that should be considered when determining the scenario of the EU energy development according to climate policy was defined by correlation analysis.
According to the negative scenario and under the influence of the effects of the Russian invasion of Ukraine, the value of greenhouse gas emissions in the EU at the beginning of 2030 will be 0.752911 tons per capita. The positive scenario shows greenhouse gas emissions can be reduced to 0.235225 tons per capita.
The study results proved two extreme scenarios of greenhouse gas emissions, depending on how to overcome the energy crisis.

Acknowledgment
The authors appreciate the copyright holder: © European Union, 1995–2022, as well as the source of the extracted data, which is the European Commission website, Eurostat http://ec.europa.eu/eurostat (accessed on 16 October 2022).
This study was funded by the European Union (the project No. 101048079 – EU4SmartED – ERASMUS-JMO-2021-HEI-TCH-RSCH); by the Ministry of Education and Science of Ukraine (projects No. 0122U000788, 0122U000769, 0121U109553, 0120U102001, 0122U000777).
This research was funded by Faculty of Organization and Management of the Silesian University of Technology (grant number: 13/990/BK_23/0178).

The rapid development of information technologies poses challenges to various processes of the financial departments of companies or the state. The aim of the paper is to substantiate the main directions of global research on information technologies for financial control and accounting for a better perception and derivation of the potentially associated requirements, challenges, and risks under the evolutionary magnifier. Applied bibliometric and network analysis, comprising analytical and visualization tools of Scopus and VosViewer, reveals the constantly increasing research interests of scholars in the field of research that has reached its maximum in 2022 and continues to rise, especially in the countries with the frontrunner affiliations (the United States, China, and the United Kingdom). The cluster analysis identified 19 total thematic clusters, eleven at the state and eight at the corporate levels, that determined the focal research points Big Data, Blockchain, and Artificial Intelligence are similar for financial control and accounting at the state and corporate level and underlined the partial similarity in terms of technical specification (cryptocurrency) as well as differences in specific levels (social networking issues at the state level) that are reflected in the recommendations for the elaboration of significant technology interfaces for both levels under investigation.

This study aims to conduct a bibliometric analysis on the topic of public policy and financial regulation in preventing and combating financial fraud using a variety of bibliometric methods and tools, including the in-built tools of Scopus by Elsevier (SciVal) and Web of Science by Clarivate Analytics, as well as VOSviewer software. The most relevant publications related to the search terms were identified. Based on the results, a map illustrating the interrelationships of concepts such as “financial fraud,” “public policy,” and “financial regulation” with other categories was created, allowing for the identification of five clusters, each of which was characterized in detail. The results of the evolutionary and temporal analysis of scientific research showed that before 2000, scholars focused on the legislative aspects of combating financial fraud; from 2000 to 2015, on risk management and the impact of financial fraud on economic growth; from 2016 to the present, on the search for methods and tools to detect and combat financial fraud. The spatial analysis confirmed a predominantly intercontinental connection between researchers. The comparison of subject areas demonstrated the interdisciplinary nature of the study, with a predominant focus on the fields of “computer science” and “economics, econometrics, and finance,” which is logical considering the economic nature and the ongoing technological transformation of financial fraud. The results can be utilized to develop new strategies, policies, and legislative initiatives to ensure financial integrity and increase confidence in financial systems.

Acknowledgment
This study is funded by the Ministry of Education and Science of Ukraine and contains the results of the projects No. 0123U101945 “National security of Ukraine through prevention of financial fraud and money laundering: War and post-war challenges”, 0121U109559 “National security through the convergence of financial monitoring systems and cyber security: Intelligent modelling of financial market regulation mechanisms” and by the Vega Agency No. 1/0638/23.

This paper explores how the war in Ukraine changed the interest in higher education of Ukrainians who stayed on the territory of Ukraine and emigrated to other countries. The methodology is based on Google Trends Analysis and peak approach with Google Trends Scale of Internet user inquiries about higher education from June 20, 2021 to June 20, 2023 with a middle point on February 24, 2022. Dynamics of changes in the queries of Internet users by keywords regarding studied higher education are: 1) exclusively from the territory of Ukraine; 2) from the territory of Poland, Slovakia, Germany, the Czech Republic, Great Britain, Spain, Italy, Bulgaria, Romania, Moldova, Austria, i.e., top-10 countries by number of registered Ukrainian refugees according to the UN Refugee Agency. The key results are: 1) increased interest of Internet users in higher education after beginning of the full-scale war: Poland – 22.9%, Romania – 28.9%, Ukraine – 31.2%, Hungary – 32.4%, Slovakia – 35.8%, Moldova – 49.0% of average number of «university» inquiries; 2) increased requests for professional education (42.2%), distance education (25.6%), distance learning (34.1%) after February 24, 2022; 3) correlation between negative trends of interest per 32% from July 2021 (100 GT Scale) to July 2022 (68 GT Scale) in Ukraine and positive trends of this indicator in European counties in August 2022 (80-100 GT Scale). Chi-square test showed statistical significance of changes in interest in higher education (p-value = 0). Key findings demonstrate the following trends after February 24, 2022: distance learning development, increased Internet users’ orientation towards professional education for high-paying jobs, popularity of flexible schedules.

Acknowledgments
The educational outcomes in this publication were created with the support of the EU Erasmus+ program within the framework of projects ERASMUS-JMO-2021-HEI-TCH-RSCH-101048055 – «AICE – With Academic integrity to EU values: step by step to common Europe» and ERASMUS-JMO-2022-HEI-TCH-RSCH-101085198 «OSEE – Open Science and Education in Europe: success stories for Ukrainian academia».

Transparency is a fundamental necessity for the insurance market in the modern fast-changing and digital world. The study aims to establish, based on bibliometric analysis, the research trends and subject areas of the insurance market transparency, including the impact of digital technologies, regulatory initiatives, and the internal policies of insurance companies. A bibliometric analysis of papers published in the journals indexed by the Scopus database for the years 1988–2023 was conducted to achieve this goal. Five clusters have been identified based on the analysis of the shared use of keywords, demonstrating the multidisciplinary nature of the research subject. They cover government regulation and risk management; ethics; technological innovations in increasing transparency; transparency of prices and costs in health insurance; and state medical insurance transparency. The analysis of insurance market transparency trends has allowed identifying four key stages of development: post-crisis regulatory mechanisms (2013–2016), Solvency II regulation effectiveness (2017–2019), transparency during the pandemic (2020–2021), and the impact of digital innovations since 2021. Spatial clustering made it possible to identify five groups of countries whose representatives are co-authors of research on insurance market transparency. The leading countries in research on insurance market transparency are the USA, the UK, and Germany.

Acknowledgment
This research was funded by the Ministry of Education and Science of Ukraine (projects No. 0122U000774 “Digitalization and transparency of public, corporate and personal finance: the impact on innovation development and national security”, No. 0123U101945 “National security of Ukraine through the prevention of financial fraud and money laundering: war and post-war challenges”). This research was funded under the research subsidy of the Faculty of Organization and Management of the Silesian University of Technology in Poland for the year 2023 (13/990/BK_23/0178).

Considering Ukraine’s corruption scandals at all levels of public governance, combating corruption and enhancing transparency have become a pivotal factor in maintaining the trust of Ukrainian citizens and foreign partners in central and local authorities. It is also an essential prerequisite for Ukraine’s prospective membership in the EU and the allocation of financial assistance from external donors. The study aims to examine how transparency in local governance influences the level of corruption in regional cities of Ukraine. The paper examines how transparency in local authorities relates to different types of corruption, including bribery within municipal services, healthcare, and other public sectors. Utilizing panel data from 24 Ukrainian cities collected between 2017 and 2020 (all-Ukrainian sociological municipal survey and project ‘Transparent, Financially Sound and Competitive Local Governments in Ukraine’), the study employs both random and fixed-effects panel regression analyses to assess the impact of various governance indicators on corruption levels across different sectors, including municipal services, healthcare, and education. The findings suggest that higher transparency of the local authorities is generally associated with lower levels of bribery in the housing and communal services sector (estimation coefficient = –0.204226), in registration and licensing institutions (–0.5353756), in healthcare institutions (–0.2032171), and experience of bribing local authorities (–0.2505674). The analysis concludes that enhancing transparency may significantly reduce corrupt practices within local government operations, thereby strengthening public trust and bringing Ukraine closer to meeting European Union standards.

Acknowledgment
Serhiy Lyeonov, Serhii Drozd, and Yaroslаv Reshetniak thank the project 0123U101945 “National security of Ukraine through prevention of financial fraud and money laundering: war and post-war challenges” for carrying out their part of this research.
This study was funded by the European Union grant “NextGenerationEU through the Recovery and Resilience Plan for Slovakia” (No. 09I03-03-V01-00130) and project VEGA – 1/0392/23 “Changes in the approach to the creation of companies’ distribution management concepts influenced by the effects of social and economic crises caused by the global pandemic and increased security risks.”

This study aims to examine how different types of pro-environmental video content (featuring humans versus AI-generated characters) influence household waste sorting attitudes and behaviors among Ukrainian residents. The research was conducted in two stages using a mixed-method approach. In the first stage, 102 individuals aged 18–45 watched two videos on waste sorting and completed an online questionnaire. Cluster and variance analyses were performed using Statistica software. In the second stage, 35 participants underwent a laboratory-based emotion analysis using iMotions software, heart rate monitors, and galvanic skin response sensors at the Behavioral Lab of Sumy State University (Ukraine) from May to July 2024. The results revealed that videos featuring real people were more effective in generating interest (average rating: 3.5 vs. 3.2) and emotional engagement, particularly joy and contempt, which were the most frequently expressed emotions. Cluster analysis identified four distinct respondent groups. Cluster 1 (39.2%) – primarily young women – responded positively to human-led videos but showed limited behavioral change. Cluster 2 (19.6%) – women aged 26–35 – reacted positively to both videos and were most willing to adopt waste sorting behavior. Cluster 3 (23.5%) – primarily men – showed moderate engagement and sorted waste occasionally. Cluster 4 (17.6%) – highly educated women – exhibited the least positive responses and were least likely to change their behavior. The emotion analysis confirmed that videos featuring real people elicited stronger emotional responses across all categories, whereas AI-generated videos prompted higher levels of anger but generally weaker engagement.

Acknowledgments
The authors would like to acknowledge the Behavioral Laboratory at Sumy State University for providing the essential facilities and resources that enabled the successful completion of this research. Additionally, sincere appreciation is extended to all study participants for their valuable time, commitment, and contributions, which significantly enriched our understanding of consumer behavior related to waste management and the perception of advertising content.
The research is supported by the International Visegrad Fund: Visegrad Fellowship Program. Project № 62410031, “Marketing research consumer behaviour in the waste management system”, and by the budget of the Ministry of Education and Science of Ukraine (research topic 0123U100112 “Post-war recovery of the energy industry of Ukraine: Optimization of waste management taking into account the health of the population, environmental, investment, tax determinants”.

In an environment where public funding is insufficient to meet international climate and energy goals, feed-in tariffs serve as an essential mechanism to mitigate investment risk and foster the participation of insurance companies as institutional investors in the renewable energy sector. This study aims to investigate whether feed-in tariff policies enhance the evolving effect of insurance sector development on renewable energy consumption across countries and over time. Given that both financial sector capacity and renewable energy transitions are dynamic processes, the analysis explicitly applies econometric techniques designed to capture temporal changes and investment inertia. Using panel data econometric techniques, including fixed effects models with cluster-robust standard errors and dynamic panel estimation (Arellano-Bond GMM), the analysis covers 64 countries from 2000 to 2020. The results reveal that greater insurance sector assets positively correlate with higher renewable energy consumption, with a coefficient of 0.143 (p < 0.01) in the fixed effects model. Still, the strength and significance of this relationship are notably enhanced when feed-in tariffs are in place, as shown by a positive and statistically significant interaction term (coefficient 0.051, p < 0.05) after adding time-fixed effects. The empirical results show that insurance companies can serve as critical institutional investors in the renewable energy sector. Still, their active participation critically depends on supportive policy frameworks, with the positive association between insurance company assets and renewable energy consumption becoming significant, particularly in countries with feed-in tariff schemes.

Acknowledgment
This study was prepared as part of the project IZURZ1_224119/1 (Swiss National Science Foundation) and the National Scholarship Programme of the Slovak Republic.
The publication was funded by the European Union grant “NextGenerationEU through the Recovery and Resilience Plan for Slovakia” (No. 09I03-03-V01-00130) and project VEGA – 1/0392/23 “Changes in the approach to the creation of companies’ distribution management concepts influenced by the effects of social and economic crises caused by the global pandemic and increased security risks.”

As the global community intensifies efforts to transition toward sustainable energy systems, the role of institutional and fiscal arrangements in fostering renewable energy has gained increasing attention. This study aims to assess whether fiscal decentralization contributes to the expansion of renewable electricity generation in OECD countries by analyzing panel data and identifying the direction and significance of this relationship. Utilizing a panel dataset of 34 countries spanning 2000–2023, the analysis employs a fixed-effects regression model with Driscoll-Kraay standard errors. It includes a one-year lag of fiscal variables to ensure robustness. The findings reveal a statistically significant but modest negative relationship between the share of subnational revenues in GDP and the share of renewables in electricity generation, suggesting that greater fiscal decentralization may not automatically incentivize renewable energy adoption. More specifically, the fixed-effects model corrected for heteroskedasticity and autocorrelation indicates that the coefficient for lagged subnational revenue (as a percentage of GDP) is negative and marginally significant (p ≈ 0.057), hinting at a potential delayed inhibitory effect. Additionally, country-level fixed effects demonstrate substantial heterogeneity, with nations like Iceland, Norway, and Canada showing systematically higher renewable electricity shares, regardless of fiscal structure. These results underscore the importance of complementary institutional frameworks and national coordination mechanisms to ensure that decentralization effectively supports climate policy goals.

Acknowledgment
This study was carried out within the framework of a research grant awarded by the Swiss National Science Foundation (grant no. IZURZ1_224119/1) and funded by the European Union grant “NextGenerationEU through the Recovery and Resilience Plan for Slovakia” (No. 09I03-03-V01-00130) and project VEGA – 1/0392/23 “Changes in the approach to the creation of companies’ distribution management concepts influenced by the effects of social and economic crises caused by the global pandemic and increased security risks”.

Type of the article: Research Article

Abstract
Decentralization and renewable energy have gained significant global attention due to their potential to enhance energy security, promote sustainability, and democratize energy access. This study aims to provide a comprehensive bibliometric analysis of research trends, key contributors, and thematic developments in the field of the decentralization of energy sources and their renewability. The research methodology involves a bibliometric analysis based on data extracted from the Scopus database, covering publications from 1973 to 2025. The analysis reveals exponential growth in research output, particularly after 2014, with over 3,700 publications recorded in 2023 alone. Citation trends indicate that foundational studies on decentralized microgrids and distributed energy systems remain highly influential, while recent works on blockchain-based energy trading and AI-driven energy management are gaining prominence. The study identifies China (11.7% of total publications), the United States (6.5%), and India (5.7%) as the leading contributors, with significant research activity also observed in European countries. Additionally, journals such as Applied Energy, Renewable Energy, and Energies serve as the primary publication platforms in this domain. Thematic analysis highlights a shift from bioenergy and land-use studies toward smart grids, energy storage, artificial intelligence, and decentralized finance for energy markets. Furthermore, co-authorship and international collaboration have increased significantly, with 25% of papers involving multi-country research efforts. Keyword analysis indicates growing research interest in emerging topics such as hydrogen energy, demand-side management, and digitalization in decentralized energy systems. These findings underscore the increasing interdisciplinary nature of decentralized energy research, integrating technological, economic, and policy dimensions.

Acknowledgment
This study was prepared as part of the project IZURZ1_224119/1 (Swiss National Science Foundation).

Type of the article: Research Article

Understanding the alignment between public interest and academic research is increasingly relevant in the context of global sustainability challenges. This study aims to investigate the relationship between societal attention, as measured by Google Trends, and scholarly output on renewable energy and the shadow economy. Using bibliometric data from Scopus and Web of Science alongside global Google Trends data from 2004 to 2025, the analysis employed Pearson and Spearman correlation coefficients, Granger causality, and distance correlation to assess the strength, direction, and form of association between public search trends and academic activity. The results reveal a significant Granger-causal relationship from public searches on “renewable energy” to academic publications, with F-statistics above 5.2 (p < 0.01), and strong positive correlations (Pearson r = 0.72; Spearman ρ = 0.69; distance correlation = 0.63). In contrast, the terms “informal economy” and “feed-in tariff” demonstrated weak or inconsistent associations, with correlations below 0.25 and statistically insignificant causality tests (p > 0.1). Cross-country comparisons further highlighted uneven alignment, with India showing high search intensity (Google Trends index > 75) but relatively low publication volume (< 2% of global output). At the same time, South Africa displayed closer coherence, with both indicators moving in tandem (r ≈ 0.61). These findings underscore scholarly research’s partial and asymmetric responsiveness to public demand, varying significantly by topic and geographic context. Moreover, while Google Trends offers robust signals of societal interest, disparities in digital access and literacy reduce its universality, pointing to critical underexplored research gaps with direct policy relevance.

Acknowledgment
This study was prepared as part of the project supported by the National Scholarship Programme of the Slovak Republic, the project 101127491-EnergyS4UA-ERASMUS-JMO2023-HEI-TCH-RSCH. Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or European Education and Culture Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. This research was funded by the grants VEGA 1/0689/23 “Sustainable growth and the geopolitics of resilience in the context of crisis prevention” and VEGA 1/0254/25 “Artificial Intelligence and FDI-invested Business Service Centers: Selected Macroeconomic and Corporate Aspects”.

Type of the article: Research Article

Abstract
As governments worldwide intensify efforts to achieve decarbonization, the role of fiscal and public policy instruments in shaping energy transitions has gained critical importance. This study evaluates how budgetary measures, taxation schemes, subsidies, and regulatory standards influence renewable electricity outcomes, thereby linking climate policy design with broader public and municipal finance issues. The analysis relies on panel data from 48 OECD, OECD negotiating members, and OECD participating partner-countries between 2009 and 2022, estimated with fixed and random effects models in R Studio and tested for robustness using Driscoll-Kraay and cluster-robust standard errors. The findings indicate that, compared with other instruments, feed-in tariffs (β = 0.116, p < 0.001), planning for renewables expansion (β = 0.070, p < 0.01), and air emission standards (β = 0.170, p < 0.001) provide the strongest and most consistent support for renewable electricity development. Renewable energy certificates and auctions also contribute positively, though with weaker statistical significance, while fossil fuel excise taxes and coal bans display mixed or context-dependent effects. The adjusted R² of 0.38 for renewable electricity generation and 0.44 for renewable electricity supply demonstrates the explanatory relevance of the selected policy variables. Robustness checks further confirm the enduring importance of feed-in tariffs as a cornerstone of fiscal support for renewables. Finally, cross-country heterogeneity is evident, with strong positive random effects in Bulgaria (0.86), Slovenia (0.73), and Czechia (0.81), and pronounced negative effects in Saudi Arabia (–1.23), Costa Rica (–1.22), and Chile (–0.95).

Acknowledgment
This study was prepared as part of the project 101127491-EnergyS4UA-ERASMUS-JMO2023-HEI-TCH-RSCH and as part of the project “From Dependency to Resilience: Renewable Energy Transformation in Post-Soviet States – A Multi-Level Analysis of Key Drivers of Success” within the Philipp Schwartz Initiative, funded by the Alexander von Humboldt Foundation. However, views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or European Education and Culture Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. The authors are thankful to the Silesian University of Technology and the National Scholarship Programme of the Slovak Republic for their support in carrying out this research.

Type of the article: Research Article

Abstract
The interconnection between renewable energy development and the shadow economy has become increasingly important as governments pursue sustainability objectives alongside fiscal transparency and the fight against tax evasion. This study aims to analyze how informal economic activity shapes the deployment of renewable energy and how renewable initiatives may support economic formalization and social responsibility. A bibliometric study of 161 documents retrieved from Scopus and Web of Science was conducted using Biblioshiny, assessing metadata completeness, thematic structures, author productivity, and collaboration networks. The results show excellent metadata coverage (abstracts, titles, and document types at 100%), though cited references were completely missing (100%), with keywords absent in 18% of records. Research output accelerated after 2015, with 2020 being the year with the highest citation velocity (7.81 citations/year), driven by two publications with over 100 citations each. Thematic mapping identified “renewable energy,” “shadow economy,” and “sustainable development goals” as motor themes, while “circular economy” and “policy uncertainty” emerged as basic but growing clusters. International collaboration accounted for 38% of documents, though single-country studies remain dominant, and citation analysis revealed a steady rise in impact, with top sources surpassing 120 citations. The analysis confirms a growing yet fragmented field, highlights the dual role of informality, from undermining fiscal revenues to supporting decentralized energy, and points to governance, circular economy, and policy risk as critical areas for future research.

Acknowledgment
This study was prepared as part of the project IZURZ1_224119/1 (Swiss National Science Foundation) and the National Scholarship Programme of the Slovak Republic. This article funded by Daugavpils University (Latvia), EKA University of Applied Sciences (Latvia).