VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Solving class of mixed nonlinear multi-term fractional Volterra-Fredholm integro-differential equations by new development of HAM
No full textThis work implements the standard Homotopy Analysis Method (HAM) developed by Professor Shijun Liao (1992), and a new development of the HAM (called ND-HAM) improved by Z.K. Eshkuvatov (2022) in solving mixed nonlinear multi-term fractional derivative of different orders of Volterra-Fredholm Integrodifferential equations (FracVF-IDEs). Other than that, the existance and uniqueness of solution as well as the norm convergence with respect to ND-HAM, were proven in a Hilbert space. In addition, three numerical examples (including multi-term fractional IDEs) are presented and compared with the HAM, modified HAM and ”Generalized block pulse operational differentiation matrices method” developed in previous works by illustrating the accuracy as well as validity with respect to ND-HAM. Empirical investigations reveal that ND-HAM and the modified HAM yields the same results when control parameter ℏ is chosen as ℏ = −1 and is comparable to the standard HAM. The findings discovered that the ND-HAM is highly convenient, effective, as well as in line with theoretical results
Development and analysis of an efficient Jacobian-free method for systems of nonlinear equations
No full textA multi-step derivative-free iterative technique is developed by extending the well-known Traub-Steffensen iteration for solving the systems of nonlinear equations. Keeping in mind the computational aspects, the general idea to construct the scheme is to utilize the single inverse operator per iteration. In fact, these type of techniques are hardly found in literature. Under the standard assumption, the proposed technique is found to possess the fifth order of convergence. In order to demonstrate the computational complexity, the efficiency index is computed and further compared with the efficiency of existing methods of similar nature. The complexity analysis suggests that the developed method is computationally more efficient than their existing counterparts. Furthermore, the performance of method is examined numerically through locating the solutions to a variety of systems of nonlinear equations. Numerical results regarding accuracy, convergence behavior and elapsed CPU time confirm the efficient behavior of the proposed technique
A joint discrete limit theorem for Epstein and Hurwitz zeta-functions
No full textIn the paper, we obtain a joint limit theorem on weak convergence for probability measure defined by discrete shifts of the Epstein and Hurwitz zeta-functions. The limit measure is explicitly given. For the proof, some linear independence restriction is required. The proved theorem extends and continues Bohr–Jessen’s classical results on probabilistic characterization of value distribution for the Riemann zeta-function
Constitutive memory equations for auxetic materials
No full textIn this note we suggest a set of constitutive equations for anelastic materials whose internal structure can present anomalous variations resulting from external effects of tension/compression, as in auxetic media. For these problems we require of a new function related with the variation of internal structure, which allows us to define a threshold separating the internal structure media from the classic ones. The equations are formulated in the case of static problems but also when the material has memory or plastic properties in addition to auxetic ones. In order to limit the complexity of the formulae, the discussion is limited to the case where the perturbation is one dimensional, which however does not limit the significance of the results
Accessibility of public transport for people with disabilities: a systematic literature review
No full textThe use of public transport is a facilitator for the development of people′s abilities and a channel for their participation in society. Mobility limitations are a cause of social exclusion and people with disabilities is one of the groups most likely to suffer from it. Problems using public transportation are among the main causes for this exclusion. The aim of this research is to conduct a systematic review of the published literature on to public transport accessibility for people with disabilities. We have found articles published in peer-reviewed scientific journals between 2010 and 2022, searching in Web of Science Core Collection (WoS) and Scopus databases implementing the Systematic Literature Review (SLR) methodology and applying Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Of the 2224 documents found during the initial search, we selected 65 articles according to the criteria used, more than 60% of them published in the last 4 years. Despite the growing literature on public transport and disability, there is still little research into this area, with the urban bus being the most studied mode of transport; and physical disability the most analysed in the articles identified
An analysis of the Indian Economy during the three COVID-19 pandemic waves
No full textThe objective of the study was to examine the effects of the COVID-19 pandemic on India’s economy. The analysis focused on several economic metrics, including stock market prices, the rupee’s value in relation to the US dollar, economic activity, the unemployment rate, and the rate of inflation. Contrary to popular belief, the results demonstrate that during the first wave (25 March 2020 to 16 September 2020), the increasing number of cases had a beneficial influence on economic activity and a negative impact on the unemployment rate. The second wave, which lasted from 15 March 2021 to 17 July 2021, was considerably stronger and demonstrated how confirmed instances had a significant detrimental impact on inflation rates and stock values. Contrary to expectations, the third wave (December 28, 2021, to January 30, 2022) was found to be less intense. Overall, the report shows how the pandemic affected India’s economy during each of the three waves and notes that there have been encouraging signs of recovery during the return to normalcy phase. The government, scholars, policymakers, and economists will find this study useful in understanding how the COVID-19 Pandemic affected the Indian economy and in coming up with ideas for future risk mitigation measures.
First published online 26 August 202
TFP shocks and endogenous innovation ability in manufacturing industry: from the perspective of structural stickiness
No full textThis paper identifies the systemic shocks of total factor productivity (TFP) at the macro level and industry level, and then evaluates the structural stickiness of TFP shocks by using information entropy and industry correlation degree through counterfactual structural simulation based on China’s manufacturing companies. We find that: in the face of TFP systemic shocks, the industries with less structural stickiness include computer communication and other electronic equipment manufacturing, special equipment manufacturing and general equipment manufacturing, indicating that these industries have a strong internal innovation power. The TFP distribution of electrical machinery and equipment manufacturing industry and ferrous metal smelting and rolling industry showed structural differentiation, and the lower tail enterprises are not sensitive to TFP shocks. The industries with strong structural stickiness are non-ferrous metal processing industry and non-metallic mineral products industry, etc., which have weak internal innovation power and need exogenous innovation incentives. In addition, there is a significant positive correlation between industry correlation and information entropy, which emphasizes the radiation effect role of industries with high industry correlation degree. The research provides a new method to evaluate the innovation ability of the industry and a basis for the differentiation of innovation incentive policies in the industry.
First published online 15 November 202
Can green bonds hedge against geopolitical risk? A cross-market connectedness analysis with portfolio implications
No full textThis study investigates whether green bonds (GBs) can hedge against geopolitical risk (GPR). This study extends the booming literature on GPR and GBs, develops a modified connectedness network model to measure the connectedness between GPR and GBs, confirms the hedging property of GBs against GPR, and becomes the first to discuss alternative hedging properties of GBs against GPR. We find evidence of market-, time-, and quantile-varying linkage between GPR and GB markets based on the time-varying Granger causality test and quantile extended joint spillover index model. We confirm via a regression model that only the GB markets in China and Japan can hedge against GPR. At the same time, GB in China remains a weak hedging and safety-haven asset simultaneously. The results remain robust for alternative proxy variables, data frequency, and model specification. Finally, the MVP approach provides superior performance while maintaining weak hedging and safety-haven properties against GPR. This study has considerable portfolio-related implications: (1) it offers an efficient hedge (i.e., GB) against GPR, (2) the heterogeneous performance of regional GB markets reminds investors to be cautious when selecting GBs assets, and (3) it encourages reasonable investment allocations on GBs to achieve a balance between profit and risk.
First published online 24 September 202
Fiscal sustainability and economic growth in the light of new economic governance
No full textThis research estimates the effects of public debt on economic growth. In addition, it contributes to examining the impact of public debt on investment as a possible channel of impact on economic growth. The empirical analysis is based on a smooth transition panel data regression model. The results show the non-linear relationship between public debt and economic growth for the sample of 12 Euro area countries is markedly statistically significant. The sustainable threshold for this relationship is on average between 93% and 105%. This implies that public debt to gross domestic product ratios above this sustainable threshold would have a negative effect on economic growth. Although insignificant, the results for the sample of 20 Euro area countries could indicate that for the less developed Euro countries the potentially negative effects of high debt can already be seen at a lower level of public debt, which is the case for even more sensible debt reduction policies. Taking into consideration the fiscal rules, the results suggest that one size does not necessarily fit all. Moreover, the trade-off between fiscal consolidation and increased green public investment will be one of the key challenges of this decade given the reinstated European Union fiscal rules.
First published online 16 April 202
The drivers of export product diversification in China: does natural resource endowments matter?
No full textExport product diversification (EPD) mitigates a country’s vulnerability to global trade shocks, contributes to its high-quality economic progress, and increases its resilience. Natural resource endowment (NRE) is considered as one of the important determinants of EPD that is less explored by scholars. The contribution of NRE to EPD will remain a matter of debate in China. The paper aims to identify the drivers of the diversification of export products in China using the province level data from 2011 to 2019. It considers key determinants including foreign direct investment (FDI), human capital (HC), technological innovation (TI), and trade openness (TO). The results of the Fixed Effect-Driscoll-Kraay standard errors (FE-DKSE) indicate a positive and significant relationship between NRE and EPD. This suggests that a rise in NRE within a country promotes EPD. Furthermore, FDI, TO, TI, and HC have statistically significant positive links with EPD. Moreover, the findings of our research are consistent across all regions. The robustness analysis provides evidence that our findings are both significant and robust. The empirical findings indicate that the included variables are fundamental determinants of EPD, which provides policymakers with crucial policy implications. To encourage EPD, the government should implement policies that stimulate these determinants.
First published online 05 February 202