VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Accuracy test of satellite imagery-derived bathymetry in shallow waters using Sentinel-2A multispectral imagery
No full textContinuous bathymetry mapping for shallow waters is very important considering that these waters are prone to change. Bathymetry measurements obtained from satellite imagery are an alternative that can be used. This study aimed to evaluate and develop algorithms that can be used to estimate shallow water depth values obtained from satellite imagery. In this study, the depth mapping results were obtained from Surface Reflectance derived from Sentinel-2A image processing. A comparative analysis was performed by comparing measurements obtained with an echosounder and estimated depths estimated with Lyzenga, Stumpf, and modified Stumpf algorithms. In this study, where the depth ranged from 2–6 meters, the Lyzenga algorithm performed the best algorithm with the R2 value of 0.94 and the RMSE 0.23, followed by the modified Stumpf algorithm with an R2 value of 0.93 and RMSE 0.24, and Stumpf algorithm with a R2 value of 0.88 and a RMSE of 0.32. Overall, this study provides an important contribution to comparing Lyzenga and Stumpf algorithms for estimating water depths. This study provides guidance on choosing the correct algorithm for bathymetric mapping using satellite imagery in similar water locations
Tail risk diversification strategy with flight-from-loss approach: Evidence from U.S. REITs
No full textThis study introduces a novel portfolio allocation strategy, the flight-from-loss approach, designed to diversify tail risk in the REIT market. The strategy reallocates capital toward assets that have historically outperformed during periods of extreme REIT losses, aiming to reduce downside risk and improve portfolio efficiency. Using U.S. REIT data from 1993 to 2023, we demonstrate that our portfolio approach reduces tail risk significantly, while also enhancing Sharpe ratios compared to a REIT-only benchmark portfolio. These diversification benefits are particularly significant during market crises, such as the subprime mortgage crisis, when risk reduction exceeds 30%. Our analysis further reveals that the minimum-variance and tangency portfolio approaches consistently outperform the equal-weight method in both risk control and performance efficiency. To test the strategy’s generalizability, we applied it to the Fama-French 30 industry portfolios, where the results of some industries indicate even stronger risk reduction and Sharpe ratio gains than in the REIT market. These findings suggest that the flight-from-loss strategy offers a practical, cross-sector solution for managing concentrated portfolio risks
Exploring search strategy for systematic literature review: evidence from the International Journal of Management Reviews
No full textSystematic literature reviews (SLRs) advance management theory and practice by synthesizing knowledge in a structured and transparent manner. However, inconsistent reporting of search strategies limits replicability and methodological rigor. To address this gap in reporting standards, the main objective of this article is to explore successful search strategies for SLRs in management research. We further propose a distinction between transparency (conceptual replication) and practical replication to clarify what constitutes a replicable review in this field. We conducted a systematic review of 57 SLRs published in the International Journal of Management Reviews and propose five criteria that search strategy reporting should meet to ensure replicability: (1) provision of a search query, (2) reporting of the query execution date, (3) indication of the search timespan, (4) clear presentation of inclusion/exclusion criteria, and (5) specification of the document sections screened (e.g., title, abstract, full text). Our findings show that most reviews support conceptual replication by providing the search query, timespan, inclusion/exclusion criteria, and screened document sections; however, practical replication remains rare due to missing details – especially the search execution date. To improve future SLRs, we recommend: (1) disclosing the review team’s underlying research paradigms and beliefs to clarify the perspective behind the synthesis, and (2) ensuring diverse team composition from the outset – or, if constrained, explicitly acknowledging such limitations. Ideally, review teams should encompass diverse contexts and paradigms aligned with the scope of the review
Airport complexity and environmental efficiency metrics for air traffic management evaluation
No full textThe aviation industry is experiencing significant growth due to the growing global demand for air travel. The International Civil Aviation Organization predicts that air passenger volumes will quadruple by 2040, putting pressure on airport infrastructure and airspace capacity. This growth is causing environmental challenges, particularly concerning emissions from aircraft operations and airport activities. These emissions contribute to local air pollution and global climate change. Airports are complex operational hubs, requiring sophisticated planning and efficient operations management to mitigate emissions and maximize throughput. This thesis investigates how airport complexity and air traffic management strategies influence inefficiencies in fuel use, time, cost, and environmental impact. Traffic scenarios were generated and analysed using MATLAB code, calculating emissions and fuel consumption across all phases of the landing and take-off (LTO) cycle. The results show significant differences in operational efficiency and environmental impact, offering insights into the effectiveness of modern traffic control methods
A comparison of transformation models between geodetic reference frames: case study in Illizi region (Algeria)
No full textThe Illizi region is an important petroleum zone in Algeria, where various seismic surveys have been conducted. The merging of adjacent surveys is not possible due to incompatible data linked to the geodetic networks. In this study, the transformation of coordinates, from the global system (WGS84) to the local system based on the Clarke 1880 A spheroid, is carried out based on a set of 57 control points well distributed over the study area with coordinates determined in both the global and local systems. Five approaches were used to determine the transformation parameters between the two systems, namely: Geocentric Translation Model, Bursa-Wolf Transformation, Molodensky-Badekas Transformation, Abridged Molodensky transformation and Multiple Regression Equations (MRE). From statistics on the determined parameters and considering its advantage of reversibility, the Bursa-Wolf Transformation Model is the most suitable model to be used to transform coordinates between the two systems in the study area. Small amount of residuals in transformed coordinates using this model indicates acceptable Bursa-Wolf parameter estimation. An improvement in the results was observed after removing of the outliers control points detected using a statistical test. For the validation of the estimated parameters, external control points were used. The results show acceptable RMS in transformed coordinates of these points
Comparison of different Mercator projection systems for the topographical survey of the Buchanan-Tokadeh (Yekepa) railway, Liberia, Africa
No full textFor this project of the Buchanan-Tokadeh (Yekepa) railway located in the Republic of Liberia, Africa, it is about carrying out comparative analysis of precisions between two projection systems, the Local Transverse Mercator (LTM), divided into 15 zones; and Hotine Oblique Mercator (HOM); as well as the projection heights of their Local Topographic Planes (LTP) both in orthometric heights to determine the scale factor, as well as ellipsoidal ones to extend the semi-axes of the ellipsoid of the WGS84 datum to give an scale factor equal to 1 of these systems, along 245 km of route, taking as reference tolerances precisions that must be within 1/40,000 or 2.5 cms per kilometer, and also that the difference in height does not exceed 150 meters. Getting results by performing survey traverse polygon made with a total station, in a way that the deformations using an LTM divided into 15 zones and the HOM expanding the semi-axes of the reference ellipsoid of the Datum WGS84 complying with the aforementioned standards
Analysis of the relationship between ESG and labor costs: the moderating effect of the legal tradition
No full textThis study examines the relationship between Environmental, Social, and Governance (ESG) scores and labor costs per employee (LCE) in firms operating under different legal traditions, specifically comparing civil law (France) and common law (United Kingdom) countries. Utilizing data from the Orbis database for the period 2020–2022, the study employs random-effects estimations with robust standard errors. Results indicate that while the relationship between ESG and LCE is not significant in common law, it is positively significant in civil law. Results are robust to alternative ESG measures, such as the social pillar score (SOCP) estimations methods and samples. The findings suggest that the legal tradition moderates the ESG-LCE relationship, with stronger positive effects observed in civil law countries. The study highlights the importance of legal frameworks in shaping the economic impacts of ESG initiatives on labor costs. While ESG concerns may result in higher LCE, and thus increased employee compensation, implementing appropriate regulations to protect workers’ rights can foster a more effective ESG-LCE relationship than relying solely on market-based regulatory systems driven by stakeholder influence
Does environmental decentralization promote green technology innovation? —Empirical evidence based on River Chief System
No full textBased on the River Chief System policy characterized by Environmental Decentralization, a double difference model was used to empirically test the impact of Environmental Decentralization on Green Technology Innovation using panel data from 283 cities in China from 2005 to 2022. Research has found that there is a significant positive impact between Environmental Decentralization and Green Technology Innovation. Furthermore, the introduction of the spatial double difference model verifies the significant positive spatial spillover effect of Green Technology Innovation. Robustness testing is also conducted through a series of methods, such as replacing explanatory variables, to confirm the robustness and credibility of the results
IFRS convergence and international trade: evidence from comparison of Türkiye and European Union
No full textThe congruence of accounting standards with high-quality financial data constitutes a cornerstone of the institutional frameworks of modern economies. The adoption of International Financial Reporting Standards (IFRS) facilitates greater transparency and comparability in financial reporting, enabling more effective allocation of resources and capital. This process enhances the stability of financial systems, improves corporate governance, and supports integration into global economic framework. This study seeks to address the following research questions: (1) How does the adoption of IFRS by Turkey influence its trade flows with the EU? (2) How do income disparities between Türkiye and EU member states interact with IFRS adoption to affect bilateral trade? (3) What is the macroeconomic importance of IFRS adoption to Türkiye’s overall trade balance? Through answering these questions, this research intends to contribute to filling an important gap in literature. The results of this research; First, IFRS adoption by Turkey reflects an immense positive impact both on exports and imports, with exports bearing more impact. This research draws attention to IFRS adoption’s role in promoting financial transparency, optimizing bilateral flows, and minimizing trade deficit in Turkey. Second, how IFRS adoption interacts with disparities in per capita income tells us more about trade behavior. Third, macroeconomic consequences of IFRS adoption are reflected in how IFRS adoption decreases Turkey’s trade deficit. The results indicate that IFRS adoption encourages exports more than imports, which points to IFRS adoption acting as an instrument to raise competitiveness and overall Turkish trade balance. This finding answers the third research question, which draws attention to how instrumental IFRS adoption is to frame trade policy and economic integration
Nonstationary heat equation with nonlinear side condition
No full textThe initial boundary value problem for the nonstationary heat equation is studied in a bounded domain with the specific overdetermination condition. This condition is nonlinear and can be interpreted as the energy functional. In present paper we construct the class of solutions to this problem