VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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The role of circular economy in achieving sustainable development goals: evidence from E7 countries
No full textCurrently, the achievement of sustainable goals has now become obligation for economies due to uncertain economic situations at global level. Thereby, this prominent issue demands the focus at academia level. The study, in this regard, attempts to explore circular economy in view with sustainable development goals (SDGs) in the criteria of E7 nations. The study has used the level of investment, level of production and consumption, level of employment, and level of education to measure the circular economy of the country. The study has also used industrialization and inflation to predict sustainable development goals achievement as the control variable. The time span chosen for the is 2001–2020 and method of moment quantile regression (MMQR) approach has been used to evaluate the variables. Results revealed that the circular economy (level of investment, level of production and consumption, level of employment, and level of education), industrialization, and inflation are positively significant with SDGs achievement in E7 countries. The study helps the policymakers in formulating policies related to SDGs achievement by improving the circular economy in the country.
First publihed online 06 June 202
Does government digitization contribute to economic growth? Empirical evidence from 109 countries
No full textIn the digital age, governments worldwide are increasingly turning to digitization to enhance efficiency and foster economic growth. This study investigates the impact of government digitization on economic growth, addressing the pressing issue of how digital transformations within the public sector can drive economic growth. First, we empirically estimate panel data from 2002 to 2021 across 109 countries using multiple statistical methods, consistently supporting that government digitization can significantly promote economic growth. Subsequently, mechanism tests are conducted using two fixed effect models containing interaction terms, revealing that government digitization can foster economic growth by curbing corruption and reducing the time businesses need to access public services. Furthermore, heterogeneity analysis confirms the moderating effects of telecommunications infrastructure, basic education popularization, natural resource abundance, government efficiency, democracy, and ruling party ideology on the relationship between government digitization and economic growth. Lastly, quantile regression reveals a nuanced pattern, indicating that as a country’s economic development level increases, the promoting effect of government digitization on economic growth initially rises before declining. These findings provide new insights for governments worldwide seeking economic growth.
First published online 04 July 202
Unveiling digital creativity: enhancing teachers’ capacities in the digital education landscape
No full textThis article aims to unveil the concept of teachers’ digital creativity, recognizing it as one of their fundamental capacities to meet the challenges posed by digital education. The theoretical segment of the article engages in a comprehensive discourse on the concept of teachers’ digital creativity. The theoretical discourse is complemented by an empirical study, engaging general education school teachers, to provide insights into their understandings and perspectives related to digital creativity. The empirical study was organized in Lithuanian general educations schools. Eleven interviews with teachers, who are already using digital tools and platforms in their teaching process, were conducted. The research findings not only enrich the understanding of teachers’ digital creativity in education, but also lay the groundwork for the further development of a robust framework of teachers’ digital creativity, offering practical considerations that may be essential for its effective formulation and implementation
Structuring and validation of photogrammetric territorial data
No full textIn the loving memory of Mariasofia Paparo, this publication focuses on the validation procedures of photogrammetric geographic information and the production and interpretation of complex reports, which are essential for handling the vast amount of generated data. Furthermore, sources of error in the structuring of geographic data and the quality parameters and conformity criteria necessary for the utilization of such data within the national geodatabase have been investigated
The (re)making of a city centre: Jan Gehl and the transformation of Melbourne CBD
No full textJan Gehl, an eminent Danish Architect and Urban Designer, has worked in more than forty cities around the world and contributed to revitalising their city centres. Although his work in Australia has drawn considerable attention in recent years, not much is known about his early and exemplary work on revitalising the city centre in Melbourne. This paper explores Gehl’s urban design work in Melbourne by examining his engagement with the City of Melbourne after being invited to lead the ‘Places for People’ initiative in 1993. Gehl’s main contributions during his collaboration with the council include developing the methodology for the Public Space Public Life surveys and co-authoring of the Places for People study reports. Gehl made several key recommendations in the reports that turned out to be instrumental in formulating urban design approaches to help transform the Melbourne CBD into a vibrant city centre. This transformation, which led to the revival of the public realm, is evident in several significant changes made to some major public spaces between 1994 and 2004 and beyond. This paper contributes to the urban design discipline by adding new knowledge of Gehl’s work in Melbourne and widening its recognition in Australia and internationally
Spatial linkages between digital economy and carbon reduction under dual carbon goals
No full textSince announcing its “dual carbon” goals, China has made reducing carbon emissions a top priority. This study utilizes panel data from 285 cities in China, from 2011–2021, to systematically examine the relationship between the digital economy and urban carbon output. It aims to identify their relationship by introducing SDM and DID model. The findings are as follows: (1) Improving the digital economy is essential to significantly lowering carbon output. These benchmark regression results have passed robustness tests. (2) The SDM model results show that the development of the digital economy significantly reduces both total and direct carbon emissions in local cities, and there is a significant spatial spillover effect. (3) The digital economy’s impact on carbon reduction varies greatly by regional distribution and city size, exhibiting significant heterogeneity
Mapping publications on value creation in construction project settings: a mixed bibliographic and bibliometric analysis
No full textThe worldwide interest on value creation has triggered an increasing number of articles, especially after a new paradigm named service-dominant logic was announced in 2004. However, limited research exists on the whole picture of value creation in the field of construction projects. Therefore, the current study is expected to reveal the status and future directions of value creation studies under construction projects. A number of 63 journal articles between 2004 and 2022 were analysed via a combined bibliographic and bibliometric approach, which covers annual publication, institutional and regional contribution, author contribution and keyword analyses. Results indicated that most published articles were based on the developed economies, such as the United Kingdom, Finland and Norway. Keywords such as megaproject, governance, social value and co-creation are emphasised, as analysed using CiteSpace software. Three implications, namely, value creation in developing areas, megaproject value creation, and perceived value perspective, are highlighted. The better understanding of the relevant literature could largely benefit academic peer researchers on value creation. Moreover, the holistic review of the literature body efficiently identifies the knowledge gaps and outlines avenues for following scholars and facilitating high-quality development of the construction engineering industry
Detection of pneumonia from chest X-rays using convolutional neural networks
No full textPneumonia detection from chest X-rays is crucial for early diagnosis, and deep learning models –specifically convolutional neural networks (CNNs) – have shown promise in automating this process. In this study, a CNN using the DenseNet-121 architecture was developed and trained, referred to as LDCS2, to classify chest X-ray images as pneumonia or normal, using a combined dataset from three publicly available sources. The CNN approach was chosen over Vision Transformers (ViT) due to lower computational requirements and better performance with limited data. A traditional training, validation, and testing split was used instead of k-fold cross-validation to reduce execution time. LDCS2 demonstrated excellent discrimination between pneumonia and normal images alongside high computational efficiency. These findings highlight the potential of DenseNet-based CNNs for automated pneumonia diagnosis, particularly in resource-constrained settings.
Article in English.
Pneumonijos nustatymas iš krūtinės ląstos rentgenogramų, naudojant konvoliucinius neuroninius tinklus
Santrauka
Pneumonijos nustatymas iš krūtinės ląstos rentgenogramų yra itin svarbus ankstyvajai diagnostikai, o giliojo mokymosi modeliai – ypač konvoliuciniai neuroniniai tinklai (CNN) – rodo didelį potencialą automatizuojant šį procesą. Šiame tyrime sukurtas ir apmokytas CNN, paremtas DenseNet-121 architektūra ir pavadintas LDCS2, skirtas klasifikuoti krūtinės ląstos rentgeno vaizdams, iš kurių matyti pneumonija arba sveiki plaučiai, naudojant sujungtą duomenų rinkinį iš trijų viešai prieinamų šaltinių. CNN metodas pasirinktas vietoje Vision Transformers (ViT) dėl mažesnių skaičiavimo išteklių reikalavimų ir geresnių rezultatų, kai duomenų kiekis ribotas. Siekiant sutrumpinti vykdymo laiką, vietoje k kartų kryžminės validacijos taikytas tradicinis mokymo, validacijos ir testavimo skaidymas. LDCS2 pademonstravo puikią atskyrimo gebą tarp pneumonijos ir sveikų plaučių vaizdų bei aukštą skaičiavimo efektyvumą. Šie rezultatai pabrėžia DenseNet pagrindu veikiančių CNN potencialą automatizuotai plaučių uždegimo diagnostikai, ypač išteklių stokojančiose aplinkose.
Reikšminiai žodžiai: LDCS2, konvoliuciniai neuroniniai tinklai (CNN), krūtinės ląstos rentgeno vaizdų klasifikavimas, pneumonijos aptikimas, DenseNet-121, medicininis vaizdavimas, gilusis mokymasis sveikatos priežiūros srityje, duomenų augmentacija, perkėliminis mokymasis
Experimental analysis of hydrogen sulfide removal from biogas using a biofilter containing cellular concrete waste and biochar
No full textThis study investigates the removal efficiency of hydrogen sulfide (H₂S) from biogas using a biofilter packed with cellular lightweight concrete (CLC) waste and biochar. A laboratory-scale biofilter was designed and tested under varying operational and environmental conditions, including inlet H₂S concentrations (100–2000 ppm), gas flow rates (0.2–1.0 L/min), temperature (25–35 °C), and humidity (70–90%). The results demonstrated that H₂S removal efficiency reached 95% at low air flow rates and 91% under low H₂S concentrations. In comparison, efficiency declined to 88% at high air flow rates and 87% at high H₂S concentrations. The combination of biochar’s adsorption properties and Fe₂CO₃-modified CLC waste’s catalytic oxidation contributed to the biofilter’s high efficiency and stability. These findings suggest that hybrid biofilters incorporating waste-derived materials provide an environmentally sustainable and cost-effective alternative for biogas purification compared to conventional chemical and physical methods.
Article in English.
Eksperimentinis biodujų valymo nuo sieros vandenilio tyrimas, taikant biofiltrą su akytojo betono atliekų ir bioanglies įkrovomis
Santrauka
Šiame tyrime nagrinėjamas sieros vandenilio (H₂S) šalinimo iš biodujų efektyvumas, naudojant biofiltrą, užpildytą akytojo lengvojo betono atliekomis ir bioanglimi. Laboratorinis biofiltras buvo suprojektuotas ir išbandytas esant skirtingoms eksploatacinėms sąlygoms: keičiant pradinę H₂S koncentraciją (100–2000 ppm), dujų srautų greitį (0,2–1,0 L/min), temperatūrą (25–35 °C) ir drėgmę (70–90 %). Tyrimo rezultatai parodė, kad H₂S šalinimo efektyvumas siekė 95 % esant mažiems oro srautams ir esant nedidelėms pradinėms H₂S koncentracijoms. Palyginimui, kai dideli oro srautai – efektyvumas sumažėjo iki 88 %, o padidėjus H₂S koncentracijoms – efektyvumas sumažėjo iki 87 %. Aukštą biofiltro efektyvumą ir stabilumą lėmė bioanglies adsorbcinės savybės bei Fe₂CO₃ modifikuotų akytojo lengvojo betono atliekų katalizinė oksidacija. Tyrimo išvados leidžia teigti, kad hibridiniai biofiltrai, kuriuose naudojamos atliekų pagrindu gautos medžiagos, yra aplinkai tvari ir ekonomiškai efektyvi biodujų valymo alternatyva, palyginti su įprastais cheminiais ir fizikiniais metodais.
Reikšminiai žodžiai: sieros vandenilio šalinimas, biofiltras, bioanglis, akytojo betono atliekos, mikrobiologinė desulfurizacija, biodujų valymas
Deflection analysis of composite reinforced concrete elements
No full textThis article examines the deflections of layered reinforced concrete bending elements, which are influenced by interlayer slip. Also, the study shows the work stages of such elements and methods for calculating their deflections. The experimental part analyzes composite reinforced concrete beam stiffness, depending on the shape of reinforcement lattice girders. Based on analytical deflection calculation methods, the deflections of tested beams under various loads are found. The obtained analytical results are compared with experimental data. After analyzing the discrepancies, an analytical method for calculating the deflection of double-layer reinforced concrete elements is developed using regression analysis. The proposed calculation method is applied to both the author’s own and other researchers’ experimental specimens, and a comparison of experimental and analytical results is carried out.
Article in Lithuanian.
Sluoksniuotųjų gelžbetoninių elementų su erdviniu tinkleliu įlinkio tyrimai
Santrauka
Straipsnyje nagrinėjami sluoksniuotųjų lenkiamų gelžbetoninių elementų įlinkiai, kurie priklausomi nuo sluoksnių prasislinkimo. Taip pat analizuojami sluoksniuotųjų gelžbetoninių elementų darbo etapai ir jų įlinkių skaičiavimo metodai. Eksperimentinėje dalyje tiriama dvisluoksnio gelžbetoninio elemento erdvinio tinklelio pavidalo įtaka konstrukcijos standumui. Pasirėmus analitiniais įlinkio skaičiavimo metodais, apskaičiuojami išbandytų sijų įlinkiai esant skirtingoms apkrovoms. Gauti analitiniai duomenys palyginami su eksperimentiniais rezultatais. Išanalizavus skirtumus, kuriamas analitinis dvisluoksnių lenkiamų gelžbetoninių elementų įlinkio skaičiavimo metodas, atliekant regresinę analizę. Skaičiavimo metodas pritaikomas asmeniniams ir kitų autorių eksperimentinių tyrimų bandiniams ir atliekamas eksperimentinių ir analitinių rezultatų palyginimas.
Reikšminiai žodžiai: sluoksniuotieji gelžbetoniniai elementai, įlinkis, analitinis skaičiavimas, eksperimentinis tyrimas, sluoksnių prasislinkimas, jungties standumas