VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
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Prediction of the anti-carbonation performance of concrete based on random forest – least squares support vector machine model
No full textConcrete carbonation is a critical factor influencing the durability and longevity of concrete structures, particularly in urban environments. Traditional methods for predicting the anti-carbonation performance (ACP) of concrete often lack precision and fail to account for complex interactions between influencing factors. In this study, a novel hybrid model combining random forest (RF) regression with a least squares support vector machine (LSSVM) is proposed to enhance the accuracy of ACP predictions. The RF regression is utilized for feature selection, identifying the most significant factors affecting ACP and optimizing the input features for the LSSVM model. Our hybrid model is validated against a comprehensive dataset, demonstrating superior performance in predicting concrete carbonation resistance compared to conventional methods. Quantitative results show that the RF-LSSVM model achieves a root mean square error (RMSE) of 5e–5 and a high coefficient of determination (R-squared) of 0.999, indicating robust predictive capability and accuracy. The main novelty of this work lies in the integration of RF and LSSVM to create a robust, accurate, and practical tool for assessing the durability of concrete structures
Feasibility study of digitalization possibilities of LEAN solutions in unit and small series production
No full textToday’s digital technology takes manufacturing to the next level. Digitized systems make it possible to identify potential and existing problems in a timely manner and to discover opportunities for improving the company’s operations by customers’ requirements as quickly as possible. In mass production, digital technologies are already widely implemented and used, which allows large companies to gain production flexibility and advantage. At the same time, large manufacturing companies gaining flexibility pose a great threat to small companies, which are creating unit and small series production. This article presents a study that aims to identify the differences between different types of production, examine digitized LEAN solutions and the latest applied technologies, and relate them to each other. This analysis will allow the selection of the most appropriate solutions for small serial and unit production. A twostage empirical study was used for this. In the first part, a questionnaire survey determines the companies’ attitude towards digitization, the LEAN tools applied, and the factors that would promote the digitization of processes. The second study compares the organization of production in a company with a low level of digitalization and in a second company with an extremely high level of digitalization. That was done by visiting companies. In a company with a low digitization level, the identified problem points are solved by applying good practices of a digitized company and by arguing from the analyzed literature sources.
Article in Lithuanian.
LEAN sprendimų skaitmenizacijos galimybių tyrimas vienetinėje ir smulkiaserijinėje gamyboje
Santrauka
Šiandien skaitmeninės technologijos perkelia gamybos procesą į aukštesnį lygmenį. Jos leidžia laiku nustatyti esamas ir potencialias problemas, atrasti įmonės veiklos gerinimo galimybes ir greičiau patenkinti kliento poreikius. Masinėje gamyboje skaitmeninės technologijos jau plačiai diegiamos ir naudojamos – tai suteikia didelėms įmonėms gamybinį lankstumą ir pranašumą. Tokios įmonės kelia didelę grėsmę mažoms organizacijoms, kuriančioms vienetinę ir smulkiaserijinę produkciją. Šiame straipsnyje pristatomas tyrimas, kurio tikslas – nustatyti skirtumus tarp įvairių gamybos tipų, išnagrinėti skaitmenizuotus LEAN sprendimus ir naujausias taikomas technologijas, atskleisti jų tarpusavio sąsajas. Atlikta analizė leidžia parinkti tinkamiausius sprendimus smulkiajai serijinei ir vienetinei gamybai. Tam pasitelktas dviejų etapų empirinis tyrimas. Pirmojoje dalyje atlikta anketinė apklausa, kuria siekta nustatyti įmonių požiūrį į skaitmenizavimą, taikomus LEAN įrankius ir skaitmenizaciją skatinančius veiksnius. Antrojoje dalyje, remiantis vizitų metu surinkta informacija, atliktas žemo ir itin aukšto skaitmenizacijos lygmens įmonių palyginimas.
Reikšminiai žodžiai: daiktų internetas (IoT), debesų kompiuterija, didieji duomenys, dirbtinis intelektas (DI), inovacijos, įrangos tarpusavio sąveika (M2M), kibernetinės fizinės sistemos, LEAN, Pramonė 4.0, skaitmenizacija, trimatis modeliavimas, vienetinė ir smulkiaserijinė gamyba
Evaluation of the quality management systems for aircraft and component manufacturing and maintenance organizations
No full textEnsuring operational efficiency is a critical condition for aviation organizations to maintain high levels of flight safety while remaining competitive. Aircraft and component manufacturing and maintenance organizations are required to comply with European Commission (EC) regulations (EU) No. 1321/2014 and No. 748/2012, which primarily focus on safety rather than broader management aspects. The EN9110:2018 standard based on ISO 9001 principles and of a recommendatory nature, offers an additional opportunity to enhance process efficiency, reduce costs, improve customer satisfaction, and support long-term sustainability. This study aimed to develop a model for assessing the effectiveness of quality management systems specifically adapted to aviation organizations. To achieve this, scientific literature was reviewed, EN9110 requirements were compared with EASA regulations, and expert surveys, interviews, and statistical data analyses were conducted. The resulting model for evaluating the impact of an integrated safety and quality management system enables the identification of relationships between operational efficiency, customer satisfaction, regulatory compliance, and audit outcomes. The findings confirm that the EN9110 standard effectively complements mandatory legal requirements, and its application provides significant benefits when leveraged as a tool for optimizing organizational performance, reducing costs, and enhancing competitive advantage within the aviation sector.
Article in Lithuanian.
Orlaivių ir komponentų gamybinių bei techninės priežiūros organizacijų kokybės valdymo sistemos vertinimas
Santrauka
Aviacijos sektoriaus organizacijoms veiklos efektyvumo užtikrinimas yra būtina sąlyga, siekiant išlaikyti skrydžių saugos lygį ir konkurencingumą. Orlaivių bei jų komponentų gamybos ir techninės priežiūros organizacijos įsipareigoja atitikti EK reglamentus (ES) Nr. 1321/2014 ir Nr. 748/2012, kurie labiau orientuoti į saugą, o ne į vadybinius aspektus. Rekomendacinio pobūdžio EN9110:2018 standartas, paremtas ISO 9001 principais, sudaro galimybę didinti procesų efektyvumą, mažinti sąnaudas, gerinti klientų pasitenkinimą ir užtikrinti ilgalaikį tvarumą. Atlikto tyrimo tikslas – sukurti kokybės valdymo sistemos veiksmingumo vertinimo modelį, pritaikytą aviacijos organizacijoms. Siekiant šio tikslo, analizuota mokslinė literatūra, lyginti EN9110 ir EASA reglamentų reikalavimai, atliktas ekspertinis vertinimas ir statistinė duomenų analizė. Sukurtas integruotos sistemos naudos vertinimo modelis leidžia nustatyti sąsajas tarp organizacijų veiklos efektyvumo, klientų pasitenkinimo, teisinės atitikties ir auditų rezultatų. Tyrimo rezultatai patvirtina, kad EN9110 standartas papildo privalomą teisinį reglamentavimą, jo taikymas suteikia reikšmingų pranašumų. Standartas aviacijos sektoriuje veiksmingai pasitelkiamas kaip priemonė organizacijų veiklai optimizuoti, sąnaudoms mažinti ir konkurenciniam pranašumui didinti.
Reikšminiai žodžiai: kokybė, sauga, valdymas, EN9110 standartas, vertinimas, veiksmingumas, aviacija
Equivalents of the Riemann hypothesis involving the Gram points
No full textThe Riemann hypothesis (RH) on zeros of the zeta-function , , states that all zeros of in the strip 0< \sigma < 1 lie on the line . Several equivalents of RH are known. In the paper, we obtain equivalents of RH in terms of self-approximation of by shifts , , where is the sequence of the Gram points
Decoding tourist satisfaction for sustainable economic development: a multi-method configuration framework using online reviews
No full textOnline reviews are crucial to understanding tourist satisfaction (TSA) in the digital tourism era. This study deconstructs the factors leading to high TSA performance in reviews, offering guidance for long-term economic benefits for destinations and businesses. Building on the three-factor theory, we create a framework utilizing text mining, affective distribution computing, and fuzzy-set qualitative comparative analysis (fsQCA) to identify patterns driving high TSA. We employ topic modeling to extract destination attributes from reviews, quantifying their performance through affective distribution computing. An enhanced Kano model classifies tourist needs based on emotional expressions in reviews. We investigate how basic, performance and excitement attributes interact and influence TSA. Additionally, we apply the coupling coordination degree model (CCDM) to analyze attribute interconnections within configurations. Our results show that no single attribute leads to specific outcomes; relatively, high TSA results from a combination of attributes. This study identifies three normative causal recipes and is the first to clarify the complex interactions in satisfaction management within the three-factor theory framework, addressing a significant knowledge gap. Ultimately, our operational guidelines aim to sustain the economic vitality of the tourism industry.
First published online 14 July 202
Innovation spillovers as a driver of economic development: evidence from regions located in Central and Eastern European Union countries
No full textInnovation has been a core element in the economic development of countries worldwide. Although innovation often has a global impact, it is created in a particular location. This research focuses on regions from Central and Eastern European Union (EU) countries as they are in the process of catching up with more developed Western EU economies. This paper aims to explore the link between innovation level and economic development in Central and Eastern EU countries from a regional perspective as well as to examine the impact of innovation spread between these regions. The analysis applies spatio-temporal models for data on the regional innovation index and gross domestic product per capita from 2016 to 2022. The results of this research show that southeastern regions had, on average, a lower level of both innovation and economic growth than western and northern ones. The analysis also confirms the positive relationship between innovation and economic development in these regions. Finally, this research proves the existence of spatial innovation spillovers: the strongest effect in Polish (near its capital city’s region) and Romanian regions while the weakest one in Slovenia, Bulgaria, and further from the capitals of Romania, Poland, and the Czech Republic.
First published online 16 July 202
The degree to which science teachers who won the Queen Rania of Jordan Award for Distinguished Teacher achieve the standards of educational excellence and creativity
No full textThe study aimed to reveal the degree to which the teachers who won the Queen Rania of Jordan Award for Distinguished Teacher achieved the standards of excellence in light of the standards approved by the award. The study adopted an analytical descriptive approach, and the sample consisted of all the teachers who won the Queen Rania of Jordan Award for Distinguished Teacher from 2013 to 2021, numbered 180 male and female teachers. To achieve the objectives, the performance evaluation tool adopted in the award was used, including specific criteria, and each criterion had several indicators, as its validity and reliability were verified before being officially approved by the Association of Queen Rania Award for Excellence in Education. The results of the analysis of the excellence standards among the sample members showed that the degree of their achievement to the standards in general was moderate, and the results also showed that there were statistically significant differences at the level α = 0.05 between the arithmetic means of the achievement degrees of standards of excellence among science teachers who won the Queen Rania of Jordan Award for Distinguished Teacher due to specialization and in favour of science teachers who won the award, while the results showed that there were no statistically significant differences due to gender
An integrated system for evaluating the impact of firm-based innovations on GDP
No full textThe study analyses the impact of innovation on the economy in the EU and related countries (Norway and Switzerland), highlighting the large differences between these countries. An integrated measurement framework is proposed to assess the long-term impact of firm-based innovations on GDP comprehensively. The literature analysis sheds light on the link between firm-based innovations and economic growth, and the study follows a three-step methodology: firstly, data on innovation and GDP are collected from Eurostat and OECD, followed by an econometric analysis to identify the links between firm-based innovation performance and economic growth, and finally, a cluster analysis is performed. This cluster analysis grouped countries according to their level of innovation and economic performance. The empirical results showed that Germany, Denmark, Finland, the Netherlands, Sweden, and Ireland have high innovation and GDP growth rates, and their innovation ecosystem contribute significantly to economic prosperity. The study confirms that innovation drives GDP growth, but its impact varies across countries depending on R&D investment, workforce skills, and policy environment. Therefore, policymakers should develop innovation strategies that consider each country’s specificities following the results of cluster analysis to maximise the economic impact
Development of an automated surface crack detection and BIM-integrated management system for concrete bridges
No full textBridge inspection work typically requires inspectors to capture hundreds to thousands of images, consuming substantial time for review. This research developed an “Automated Crack Image Cloud Detection System” and the “Auto Predictor” application, enabling automatic crack identification and deterioration image recognition through uploads. This platform integrates with the “Bridge BIM Cloud Management System”, connecting crack information with three-dimensional models. Engineers can create BIM models based on structural design drawings, while inspectors can photograph cracks and integrate relevant information. The study utilized deterioration images from long-term bridge inspections in Taiwan, covering various real-world environmental conditions. Through effective deterioration labeling strategies and comparing YOLOv4 and YOLOv7 algorithms with recommended parameters, an optimal model was obtained for system implementation. Research results demonstrate that the “Automated Crack Image Cloud Detection System” successfully identified cracks in bridge inspections and short beam shear test specimens. The deep integration with the “Bridge BIM Cloud Management System” enables automatic component crack identification and generates location charts, providing decision-makers with intuitive visual data. The YOLOv7-based model achieved a mean Average Precision (mAP) of 87.64%, significantly improving bridge inspection efficiency and demonstrating exceptional application potential
How emotional intelligence affects inter-organizational relationships in megaprojects: the boundary spanning perspective
No full textBoundary Spanners (BSs) substantially impact relationship development in megaprojects. Yet, previous research only focused on the emotional intelligence (EI) of single-level BSs, e.g., megaproject managers and decision-makers. By clustering BSs into higher-level BSs (HBSs) and middle-lower-level BSs (M&LBSs), this article aims to investigate how to enhance inter-organizational relationships through different-level BSs’ EI and boundary-spanning behaviors including ambassadors, coordination and information scanning behaviors. Data from 119 HBSs and 171 M&LBSs in 15 megaprojects were first collected with a questionnaire survey. 18 semi-structured interviews were then undertaken to give a deeper explanation to the underlying mechanism. The results show that HBSs’ EI is directly and positively associated with inter-organizational relationships. However, the benefit of M&LBSs’ EI in megaprojects can only be realized through the mediating effect of their boundary-spanning behaviors. HBSs’ EI is effective in improving external ambassadors’ activities. In contrast, M&LBSs’ EI is effective in improving information scanning. This study advanced EI and relationship study in megaprojects, stating the mechanism between these two variables varies for different-level boundary spanners