Multidiszciplináris Tudományok

Exploring stress-dependent acoustic velocity hysteresis in rocks

2024-07-29T07:46:22+02:00

Knowledge of acoustic wave velocity in rocks is essential for geophysical studies, as it helps identify geological structures that may contain hydrocarbon accumulations. Acoustic velocity is strongly influenced by pressure and the presence of pore volume. This paper integrates experimental data with theoretical modeling to investigate stress-dependent acoustic velocity hysteresis in rocks and to analyze how stress affects acoustic velocity during loading and unloading. The study focuses on quasi-static elastic properties and introduces a new petrophysical model that explains acoustic hysteresis through pore closure and opening, thereby affecting P-wave propagation. The model is consistent with the observed data and provides a coherent framework for understanding the interactions among stress, pressure, and acoustic behavior. To validate the model, a sandstone sample was tested under incremental pressures, and the model parameters were determined using a linearized inversion method. The calculated and measured velocities showed close agreement, confirming the model’s applicability.

The compliance assurance function in light of the recommendation for internal defense lines in Hungary

2025-08-05T19:44:13+02:00

The internal defense lines are closely intertwined with the overall operation and security of financial organizations. Their effective functioning is critically important not only for the organization itself but also for maintaining economic stability and societal trust. Consequently, their establishment and maintenance are indispensable for the sustainable and secure operation of the financial sector. In my study, I aim to provide a descriptive overview of the compliance assurance function, including a brief review of the literature, legal regulations, and the National Bank of Hungary Recommendation No. 12/2022 (VIII. 11.), which pertains to the establishment and operation of internal defense lines, as well as the governance and control functions of financial organizations. The purpose of the study is to present in detail the rules formulated by the recommendation regarding the compliance assurance function, emphasizing the importance of internal defense lines for the stability and integrity of the financial sector.

Real time formation prediction using machine learning models based on drilling parameters

2025-08-27T16:53:54+02:00

Accurate knowledge of formation characteristics is critical during well development, particularly in the drilling phase, as it guides trajectory planning, casing depth selection, and the design of bit, fluid, and cementing programs. Additionally, a precise lithological sequence is essential for determining optimal perforation depths and managing production. Real-time data interpretation is increasingly valuable for enabling faster decisions and reducing operational costs. Traditionally, formation interpretation relies on manual analysis of drilling logs and shaker samples by petrophysicists or geologists. This paper introduces a machine learning-based approach to predict formation types using real-time drilling and MWD parameters, demonstrating the potential to enhance accuracy and decision-making efficiency compared to conventional methods.

Audit requirements in Europe

2025-11-08T20:51:06+01:00

Statutory audit is essential for ensuring transparency and reliability in ensuring the transparency and reliability of financial reporting. In Hungary, the Accounting Act defines the mandatory cases of audit, primarily based on sales revenue and number of employees. In recent years, however, these thresholds have been significantly increased have recently been increased, significantly reshaping the audit landscape. This paper aims to provide a comprehensive overview of the statutory audit requirements in Hungary, by placing the Hungarian case in a broader European context. Given the diversity of national audit regimes within the EU, the paper explores how recent threshold changes align with or diverge from trends observed across Member States. Special attention is paid to the underlying motivations of the EU and individual countries to adjust audit obligations. The goal is to assess the potential implications of higher thresholds on audit quality, financial transparency, and the role of auditors in corporate governance.

Stability and accuracy analysis of classical time-stepping algorithms in a unified characteristic-polynomial framework

2026-02-09T13:15:09+01:00

This paper presents a unified spectral framework for evaluating the stability and accuracy of classical time-stepping algorithms via the characteristic polynomials of their approximation operators. The Central Difference Method and the Wilson–θ scheme are analysed using the undamped single-degree-of-freedom oscillator, enabling numerical effects to be distinguished from physical behaviour. Stability is established through the Jury criterion, while numerical damping and phase error are quantified from the dominant eigenvalues. The Central Difference Method is conditionally stable and amplitude-preserving but exhibits a second-order negative phase error, whereas the Wilson–θ Method achieves unconditional stability at the cost of fourth-order numerical dissipation and a positive second-order phase error. The proposed framework provides a transparent basis for comparing integration schemes and highlights the trade-off between unconditional stability and long-time accuracy.

Socioeconomic determinants and spatial patterns of poverty in Borsod-Abaúj-Zemplén County, Hungary

2025-09-21T12:20:58+02:00

This paper examines the main characteristics of people living in income poverty in Borsod-Abaúj-Zemplén County, one of Hungary’s most disadvantaged regions. Utilizing a questionnaire-based survey conducted between November 2024 and February 2025, the study analyzes the relationship between poverty status and key sociodemographic variables, including education, ethnicity, household size, settlement type, and distance from the county seat. Results indicate that lower educational attainment and Roma ethnicity are significantly associated with higher poverty rates, while rural residence and greater distance from the county seat also increase vulnerability to poverty. In contrast, household size does not show a statistically significant effect. The findings highlight persistent spatial and social inequalities in the region, emphasizing the need for targeted policy interventions focusing on education, ethnic integration, and regional development.

Smart Board

2025-10-29T19:40:29+01:00

Digitization means data is converted into a digital format that can be processed by computer equipment. Digital processing leads to digitalization, which has a significant importance, among other areas, in developing higher education. Assuming the goal is to graduate students with the highest possible level of knowledge and to enable them to perform their future jobs effectively, a strong emphasis must be placed on this field. The efforts are meaningless without renewing the teaching methods and environment; just adding some computers and software is not sufficient. The smart boards investigated in this study are advanced, integrated tools that support efficient digital education. The article presents the journey from chalkboards to digital boards, emphasizing the necessary steps for successful application. Students’ feedback on a pilot application at the University of Pannon was processed to explore the opportunities and critical issues.

Automotive project risk management in agile environments

2025-11-14T15:09:50+01:00

Automotive industry is a complex environment described by high quality standard requirements, global supply chains and high pressure to comply with latest customer expectations. Therefore risk management is essential for companies operating in this environment. In this study we aimed to understand expert opinion regarding automotive risks. Response has been collected from 119 experts mostly in automotive environment. We used Q-method to analyze dominant opinion groups and additionally requested feedback regarding proposed risk mitigation measures. Key observation is that time-related issues dominates the expert opinion. Based on the the factor analysis we revealed a major (focusing on day-to-day problems) and minor (focusing on organization and structural problems) opinion group. Subgroup analysis based on experience, methodological preference, industry and nationality reveled valuable insights to better understand risk perception. Qualitative part of the survey regarding mitigation measures showed importance of planning, monitoring and communication. The research work contributes to the understanding of risk patterns in agile automotive environment and can provide guidance for practitioners.