Journals Published by Vilnius Tech
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Some properties of solutions of α-conformable differential equations with piecewise constant arguments: existence and uniqueness, asymptotic stability, oscillation and periodicity
Get PDFConformable differential equations, based on the recently introduced conformable derivative, represent a novel and increasingly popular class of differential equations. This framework offers significant advantages over traditional models, particularly due to its simplicity and enhanced flexibility in modeling diverse phenomena. In this paper, we examine conformable differential equations with piecewise constant arguments. We establish the existence and uniqueness of solutions for these equations and derive conditions for oscillatory behavior, convergence, and periodicity. Additionally, we provide numerical examples to support and illustrate the theoretical results
The moderating effects of outside directors on the relationship between managerial overconfidence and earnings management: evidence from Korea
Get PDFThe subjective judgment and discretionary actions of a manager can influence the core strategy, investment, operations, and decision-making of a company. Managerial actions from the top, particularly the board, plays a vital role in addressing this inclination. While scholars have shown interest in examining managers’ overconfidence tendencies in recent years, few have explored the characteristics of the board members. According to the study, a high proportion of outside directors on the board of Korean companies has been observed to alleviate upward earnings management driven by managerial overconfidence. The obtained results emphasize the significance of the board of directors in enterprises and contribute to theories related to managerial characteristics. This study aims to bridge the research gap concerning managers’ tendencies of overconfidence while expanding the existing knowledge in this field. Firstly, this study aims to address the need to identify cognitive characteristics of managers. Secondly, it investigates the impact of the board of directors’ characteristics on managers’ tendencies towards overconfidence
Is fraud detection feasible without training data? Testing an expert-based approach
Get PDFWe aim to derive a fraud detection approach applicable to conditions where historical fraud data is absent, inadequate, or outdated for making predictions. To this end, we propose a new approach to fraud detection based on expert opinion, enabling tailored tools for various conditions of economic/institutional environments. For this, we determined the relative importance of common fraud indicators based on a widely used model in the literature. We then used this information to formulate a scoring alternative to conventional versions, which uses either the original coefficients or the coefficients obtained from training the model. Finally, these scoring alternatives were compared by their detection performances. The design of this research demanded a multifaceted dataset consisting of expert opinions, financial statement data of non-financial companies in the Istanbul Stock Exchange, and local regulatory authority’s notifications on fraudulent companies. The analysis of the detection performances indicates that the proposed alternative scoring method poses a feasible alternative with competitive performance and fewer data requirements. This research’s approach sidesteps the training data requirement and provides financial analysts, auditors, and regulatory bodies a versatile classifier for various use cases regarding financial data, such as detecting fraudulent financial activity, as demonstrated in this study
Firm performance in times of crisis: does an innovative business strategy matter?
Get PDFThis study examines whether a firm’s business strategy – innovative vs. conservative – determines the extent to which a crisis impacts its performance. To explore this, the study calculates business strategy scores as a composite measure of six variables, where a high (low) score indicates an innovative/prospective (conservative/defensive) strategy. The COVID-19 pandemic (2020–2021) serves as the crisis context for the analysis. Using a sample of 7,143 firm-year observations in the U.S., the study finds that while the sample firms experienced a decline in their performance during the COVID-19 crisis period compared to the pre-crisis level (2018–2019), the decline was less pronounced for firms following innovative strategies. This finding suggests that a firm’s business strategy is a crucial determinant of its performance during a crisis. The study enhances theoretical understanding that business strategy is particularly important when operating conditions are abnormal
Effectiveness of the ESG approach in portfolio selection – an empirical evidence from the US stock market
Get PDFThe purpose of this study is to explore whether ESG (Environmental, Social, and Governance) criteria can serve as a valuable tool for investors when making rational decisions about financial security selection and portfolio construction. By applying Modern and Post-Modern portfolio theories (MPT and PMPT) under the conditions of ESG and Return Max criterion, our primary objective was determined: “Is ESG a criterion for investors in the rational selection of financial securities and portfolio construction?” A five-year analysis (2018–2023) was carried out on 484 financial securities (companies) from the S&P 500 Stock Index to answer this question. Data collected included the daily close price of the S&P 500 Stock Index, its constituents (484 stocks), ESG scores, risk-free rate, and the equity risk premium of the U.S. market. The results showed that financial securities chosen based on the Return Max criterion were generally undervalued on the market; however, this was not consistently observed by ESG Max where examples of overvalued securities were also identified. Nevertheless, using the Sharpe and Sortino Ratio performance indicators, it was concluded that the return per unit of assumed risk is more appealing to investors (with risk aversion) when considering the portfolios built on the ESG Max criterion
Exploring distance learning in higher education: satisfaction and insights from Mexico, Saudi Arabia, Romania, Turkey
Get PDFEducation, notably higher education, faced a significant challenge during the last period. Our data exploratory study aims to provide insights into the key factors that define students’ Distance Learning (DL) in the current period. Based on the main findings, we justify our bold proposition for the current era of distance and blended learning in Higher Education. Our research study aims to understand cultural and national differences in four countries: Mexico, Saudi Arabia, Turkey and Romania. It contributes to the theory of DL with a model of six hermeneutic factors for the satisfaction of using the DL method. It investigated and confirmed the capacity of the components to explain 60% of the DL satisfaction variance. Our research study also emphasized the interpretation of the essential findings and the drafting of bold propositions for the DL practice, emphasising academic environments. We identified significant areas of improvement, and we suggested the orchestration of combined efforts. Our research promotes the strategic deployment of DL in the current context as a resilient strategy of institutions for high-impact training and targeting of huge audiences, with emphasis on the deployment of new tools and teaching methods customized for a new, unique value proposition of the DL
Impacts of human resources management strategies and practices on workers performance in construction industry: a review
Get PDFHuman resource management (HRM) plays a vital role in the growth and sustainability of companies and in achieving company objectives, as HRM relates to the workers’ practices and their functional roles. The main objective of this paper is to identify the HRM strategies, practices and their impact on worker’s performance in the Architecture, Engineering, and Construction (AEC) Industry. The method which was used in this study was based on three stages. After the completion of the database and web engine search, the total number of sources found were 149. Next, the sources’ titles and abstracts were reviewed and those marked as relevant to the review were chosen to be retrieved and thoroughly reviewed. The sources were chosen based on the following inclusion criteria: (a) the sources implied in HRM strategies in the AEC industry, (b) the sources released between 2010 and 2023, (c) the online sources, and (d) the English-language sources. Also, the selected sources are reviewed to extract the factors using the content analysis method which is a thorough and systematic study of the contents of a specific body of material. In addition, content analysis is carried out to extract practices of HRM strategies and their impact on worker performance. This can be followed up and observed through the figures and tables that come later. As a final result, which concludes the outputs of the previous stages which results in a first-round total of 31 HRM strategies practice but in the second-round result of reaching 39 different sources from 149 related sources. After that, discussing the most popular between them based on the appearance of it in the sources which reviewed beside that, the impact of it on worker’s performance were viewed in the AEC industry. Based on that, it was found the following 5 categories of strategies: (1) Human Resources Planning; (2) Polarization and Recruitment; (3) Training and Development; (4) Human Resources Following-up; (5) Career Planning. At the same time the most popular practices are based on appearance in sources: In terms of Human Resources Planning Strategy, “The company’s management analyses the functions accurately”. In Polarization and Recruitment Strategy, “The company’s internal resources are the best to provide its human resource needs” and “Selection and recruitment policies are in line with the company’s current and future needs”. In Training and Development of Human Resources Strategy, “The company evaluates the results of development and training programs to achieve the purpose of feedback”. In Human Resources Following-up Strategy, “There is a fair incentive system in the company”. In Career Planning Strategy, “There is a clear description of the relationship of workers to each other”. Finally, human resource management strategies and practices are one of the major players in the AEC industry, which is evidenced by its impact on the performance of workers.
First published online 22 October 202
Machine learning of electroencephalography signals and eye movements to classify work-in-progress risk at construction sites
Get PDFThe construction industry has consistently faced high accident rates and delays in recognizing hazards, posing significant risks to onsite personnel. Traditional hazard detection methods are often reactive rather than proactive, emphasizing a pressing need for innovative solutions. Despite advances in safety technology, a considerable gap remains in real-time, accurate hazard recognition at construction sites. Current technologies do not fully leverage physiological data to predict and mitigate risks. This research introduces a groundbreaking approach by employing machine learning to analyze electroencephalography (EEG) signals and eye movement data, enabling real-time differentiation of safe, warning, and hazardous visual cues. A Random Forest model with an impressive classification accuracy of 99.04% has been developed, marking a significant enhancement in identifying potential hazards. The possible impact of integrating EEG and eye movement analyses into wearable devices or onsite sensors is substantial, as it could revolutionize safety protocols in the construction industry, fostering a safer future.
First published online 31 December 202
Exploring system boundaries for green public-private partnerships
Get PDFThis study addresses the research gap in understanding the intricate dynamics of public-private partnerships (PPP) in fostering sustainable development by proposing a framework delineating eight system boundaries for green PPP. Through analysis across four cases from BRICS countries, the research illuminates the nuanced and interactive nature of these boundaries. The findings underscore the necessity of recognizing green PPP as complex socio-technical systems. The paper emphasizes the diversity and complexity of green PPP’s boundaries and highlights the importance of explicitly delineating them for meaningful comparison across contexts. By clarifying these perspectives, the study contributes to enhancing academic understanding and practical implementation of sustainable development initiatives through PPP
Evaluation of the effect of fineness of fly ash in type I and type II Portland cement blended mortars
Get PDFThis study evaluates the effects of fineness-modified Class F fly ash (FA) on the performance of Type I and Type II Ordinary Portland Cement (OPC) mortars. FA was mechanically ground to achieve 90% (GFA1) and 98% (GFA2) passing through a 45-µm sieve, replacing OPC at 10%, 30%, and 50% by weight. Comprehensive testing included compressive strength, water demand, setting time, heat of hydration, acid resistance, and microstructural analysis. Results demonstrated that increasing FA fineness reduced water demand by up to 6.3% (Type I) and 5.9% (Type II) at 30% replacement, while enhancing long-term strength. Mortars with 10% GFA2 achieved 58.6 MPa at 56 days. Type II OPC blends exhibited superior acid resistance, with mass loss reductions of 43% (50% GFA2) compared to Type I, attributed to lower C₃A content and denser microstructures. Hydration heat decreased by 10.9% in Type II OPC, further reduced by 40% with 50% FA replacement. The microstructural analysis confirmed reduced ettringite formation and enhanced compactness in FA-modified mortars, correlating with improved durability. These findings highlight the viability of finely ground FA as a sustainable supplementary material, enabling highvolume FA utilization (up to 50%). The study provides critical insights for optimizing greener cement formulations, particularly in regions prioritizing Type II OPC for sulfate resistance and moderate heat applications, advancing Malaysia’s net-zero carbon goals through reduced clinker reliance