VGTU Journals (Vilnius Gediminas Technical University - Vilnius Tech)
Not a member yet
12536 research outputs found
Sort by
The art of architecture wayfinding: navigating by objects, boundaries, and time
No full textThe purpose of this paper is to explore various forms of wayfinding through spatial reading. In particular, this article emphasizes how hidden clues play an important role in human movement and the wayfinding process. The purpose of this paper is to highlight hidden clues that are crucial to understanding architectural spatiality as a process of wayfinding. A film that contains a wayfinding narrative will be dismantled in this paper to explore various the arts of wayfinding. The selection of the films was based on the possibility of spatial reading, especially those that reflect the story of human movement and the wayfinding process. The analysis is based on observations of the film, particularly how spatial settings are compiled and used to wayfinding clues as the observed data. The data was collected by observing the actors about their wayfinding strategies. Using catalogs and diagrams, the results of the data were analyzed to obtain a spatial picture of wayfindings. Three aspects of hidden clues determine a person‘s wayfinding, namely objects, boundaries, and time. In terms of wayfinding, these three aspects may be considered outside of the physical form of architectural space. The results of the study contribute to the development of an architectural wayfinding system based on spatial narratives
Adapting the 15-minute city model in Cairo: mobility challenges and opportunities
No full textThe 15-minute city model, a visionary approach to urban planning, envisions neighbourhoods where residents can access all essential daily needs – work, education, healthcare, shopping, and leisure –within a 15-minute walk or bike ride. This study assesses the challenges and opportunities of implementing the 15-minute city model in Downtown Cairo, Egypt. The study examines the current state of public spaces, transportation, and walkability in the area through ethnographic research, including extensive field observations and frequent attendance at design workshops with developers, as well as numerous site visits and in-depth semi-structured interviews with diverse stakeholders. Stakeholders included the developer of the Cairo House project, the Cairo Bike project manager, urban researchers, tourists, residents and business owners within the study area. Data were analysed using thematic coding to identify recurring patterns and conflicting perspectives. The findings reveal significant challenges, including traffic congestion, limited public spaces, and inadequate pedestrian and cycling infrastructure. The study explores potential solutions, including enhancing public transportation, creating safe and accessible environments for pedestrians and cyclists, promoting mixed-use development, and developing vibrant and accessible public spaces. The main findings underscore the significance of community engagement and participatory planning in ensuring the successful and equitable implementation of the 15-minute city model within this unique and historic urban context
Corporate environmental responsibility in China\u27s high-pollution industry: the power of investor
No full textWe use Chinese A-share listed firms in the high-pollution industry from 2013 to 2021 as the research sample to explore the impact of investor attention on corporate environmental responsibility. We find that investor attention positively affects corporate environmental responsibility. The primary mechanisms involve increasing executive environmental awareness and strengthening government environmental regulations. Further, we find that financing constraints weaken this positive relationship, while political connections and institutional shareholders strengthen it. The conclusions remain consistent after adopting an alternative measure of the core variable, changing the regression model, and utilizing the 2SLS method. We also provide suggestions for corporate environmental responsibility from both governmental and firm perspectives
Firm performance in times of crisis: does an innovative business strategy matter?
No full textThis 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
Drivers of price volatility in Romania’s electricity markets
No full textThe paper examines the price volatility, key determinants, and autoregressive distributed lag (ARDL) framework of Romania’s Intraday Continuous Market (IDC) during the summer months. The stability of the ARDL-ECM coefficients is assessed using the cumulative sum (CUSUM) test. We explore the interaction between IDC and Day-Ahead Market (DAM) prices, alongside the influence of economic and environmental variables, including traded volumes, consumption, export/import and the generation mix. Using hourly data and econometric techniques, we identify significant short- and long-run relationships between IDC prices and their drivers. DAM prices exhibit a strong positive impact on IDC prices, reflecting tight market integration. Higher shares of Renewable Energy Sources (RES) such as wind and solar are associated with increased IDC prices, highlighting challenges in integrating intermittent resources. Conventional sources, particularly coal and oil/gas, also elevate prices due to higher marginal costs. Conversely, electricity consumption is negatively related to IDC prices, suggesting that anticipated demand patterns may contribute to system stability. The findings carry implications for policymakers, indicating a need for enhanced forecasting, flexible resources and improved inter-market coordination to ensure price stability and efficient integration of RES
Quotation impact factors for general contractors: a viewpoint from private sectors in Taiwan
No full textThe quotes provided by private sector entities to the project’s general contractor vary based on actual considerations. This research aims to identify the factors that influence these quotes for general contractors. Through an extensive review of literature and interviews with experts, four main aspects were identified, encompassing a total of 38 impact factors related to quoting patterns. A survey was conducted among construction professionals, resulting in 123 valid responses out of 146 distributed surveys. The survey’s validity was confirmed with a Cronbach’s Alpha value exceeding 0.7. Subsequently, a factor analysis was performed, confirming 38 impact factors and their respective weights. The results from the Principal Component Analysis (PCA) offer valuable managerial insights, highlighting the most impactful factors: external demand, corporate adjustment, and financial condition. These findings provide practical guidance for practitioners. These insights encompass areas such as information sharing, project limitations, and subcontractor capabilities. Contrary to stereotypes presented in prior research, factors such as reputation and social connections were found to not significantly impact quotation outcomes
Landscape change and perception along historical railway: the case of Yunnan-Vietnam Railway, China
No full textAgainst the background of environmental change, this study investigates the relationship between landscape changes and perceptions along the historical railway using a combination of Historical Geographic Information Systems (HGIS) and Fuzzy-set Qualitative Comparative Analysis (fsQCA). After quantifying the changes by GIS, the research aims to understand how different types of landscape changes affect physical, psychological, and cultural perceptions among locals. By integrating historical maps with remote sensing data and questionnaire, the study provides a comprehensive analysis of landscape evolution over time. The findings reveal that cropland and urban areas both showed significant increases along the railway; forest and water body both decreased over 70 years. The presence of forest change led to significant cultural perceptions and cropland change influenced the psychological perceptions of landscape. This research contributes to the understanding of the interplay between landscape change and human perception, offering valuable insights for sustainable landscape management and heritage conservation
Changes in land use conflict and zoning optimization in rapidly developing mountainous cities: a case study of Guiyang, China
No full textMountainous cities, influenced by complex human activities and terrain, face severe land use conflict issues. However, the spatiotemporal characteristics of land use conflict changes and the scientific questions regarding their management in rapidly developing mountainous cities remain unresolved. Therefore, Guiyang, a typical mountainous city in China, was chosen as the study area. With the support of ArcGIS technology, this research analyzed land use conflict changes and conducted zoning optimization. The study reveals a rapid intensification of land use conflicts, with high conflict areas increasing by 369%, while moderate, general, and low conflict areas declined. The conflict between production and living spaces is the predominant one, expanding by 385%. Additionally, high conflict areas between production and ecological spaces rose by 760%. Integrating land suitability, conflict, and functional differences in zoning optimization enhances core functions, mitigates conflicts, and guides land use management. The results are valuable for optimizing land use patterns and promoting healthy urban development in mountainous cities
Investigation of the thermal conductivity of RT58 phase change material during the charging process of a thermal storage tank under natural convection conditions
No full textAs global energy demand grows, more and more attention is being paid to efficient energy storage solutions, among which Phase Change Materials (PCMs) are particularly promising. They allow efficient thermal energy storage by using the latent heat that is absorbed or released during the transformation of the aggregate state. One of the most important properties of PCM for efficient heat transfer is the thermal conductivity. Unfortunately, it is not high for organic materials. This paper presents a study of RT58 PCM, presenting an experimental evaluation of the thermal conductivity of this material and the application of the material in a storage tank. The analytical evaluation focuses on the heat transfer under natural convection conditions, where the aim is to assess the influence of the thermal conductivity of the PCM on the amount of energy stored in the storage tank. In this case, the temperature of the heating surface, the magnitude of the thermal conductivity coefficient and the choice of the other PCM are considered. The experimental results allowed to refine the value of the thermal conductivity coefficient of the RT58 material used (0.188 W/(mK)) and the analytical calculations allowed to trend towards an increase of the heat exchange efficiency of the system with the PCM.
Article in Lithuanian.
RT58 fazinio virsmo medžiagos šilumos laidumo koeficiento tyrimas natūralios konvekcijos sąlygomis akumuliacinės talpos įkrovimo metu
Santrauka
Didėjant pasaulinei energijos paklausai, vis daugiau dėmesio skiriama efektyviems energijos kaupimo sprendimams, tarp kurių itin perspektyvios yra fazinio virsmo medžiagos (FVM). Jos leidžia efektyviai saugoti šiluminę energiją naudojant latentinę šilumą, kuri sugeriama arba išskiriama agregatinės būsenos virsmo metu. Viena iš svarbiausių FVM savybių efektyviems šilumos mainams yra šilumos laidumo koeficientas. Deja, organinių medžiagų atveju jis nėra aukštas. Šiame straipsnyje pateikiama RT58 FVM tyrimas, kuriame pristatomas eksperimentinis šios medžiagos šilumos laidumo įvertinimas ir medžiagos pritaikymas akumuliacinėje talpoje. Atliekant analitinį vertinimą nagrinėjami šilumos mainai natūralios konvekcijos sąlygomis, kai siekiama įvertinti FVM šilumos laidumo įtaką sukauptos energijos kiekiui akumuliacinėje talpoje. Šiuo atveju nagrinėjama šildomojo paviršiaus temperatūra, šilumos laidumo koeficiento dydis ir kitos FVM pasirinkimas. Eksperimentiniai rezultatai leido patikslinti naudojamos RT58 medžiagos šilumos laidumo koeficiento vertę (0,188 W/(mK), o analitiniai skaičiavimai – tendencijas didinti sistemos su FVM šilumos mainų efektyvumą.
Reikšminiai žodžiai: fazinio virsmo medžiaga, natūrali konvekcija, šilumos atidavimas, šilumos laidumo koeficientas
Application of global navigation satellite systems and synthetic aperture radar technology in environmental and earth surface stability research: a reviews
No full textEnvironmental monitoring technologies have advanced, offering reliable data to assess and mitigate the impacts of climate and ecosystem changes on the planet. Global Navigation Satellite Systems (GNSS) and Synthetic Aperture Radar (SAR) technology have contributed to this progress. The combined use of GNSS and SAR enriches environmental assessments, supporting programs for climate monitoring, water cycle analysis, and vegetation mapping. This integration is also crucial for tracking the movement of Earth’s tectonic plates and monitoring its stability, with GNSS measuring precise surface displacements and SAR providing detailed images of ground deformation. Several models and systems have been developed for large-scale global area monitoring, where GNSS and SAR data provide accurate measurements used to evaluate various parameters such as soil moisture, vegetation cover, glacier melting, and more. GNSS and SAR are widely used in monitoring tectonic plate shifts and Earth’s stability. A study conducted by the European Earth Movement Monitoring Service in the Kirkilai sinkhole area, covering 5.9 hectares, found that the system uses only four measurement points in such an area, which does not fully describe the situation of height changes over time. Therefore, it would be beneficial to create a local model or system for monitoring the Lithuanian territory using the same GNSS and SAR technologies.
Article in Lithuanian.
Pasaulinės navigacijos palydovų sistemų ir sintetinės apertūros radarų technologijos pritaikymas aplinkos ir žemės paviršiaus stabilumo tyrimuose: apžvalga
Santrauka
Aplinkos stebėjimo technologijos pažengė į priekį, siūlydamos patikimus duomenis planetos klimato ir ekosistemų pokyčiams vertinti ir pasekmėms mažinti. Pasaulinės navigacijos palydovų sistemos (GNSS) ir sintetinės apertūros radaro (SAR) technologija prisidėjo prie šio progreso. GNSS ir SAR papildomas naudojimas leidžia praturtinti aplinkos vertinimus, palaikant programas klimatui stebėti, vandens ciklui analizuoti ir augalijos žemėlapiams sudaryti. Ši integracija taip pat yra labai svarbi sekant Žemės tektoninių plokščių judėjimą ir stebint jos stabilumą, kai GNSS matuoja tikslius paviršiaus poslinkius, o SAR teikia išsamius žemės deformacijos vaizdus. Sukurtas ne vienas modelis ir sistema globaliems didelio masto teritorijų stebėjimams, kur GNSS ir SAR duomenys suteikia tikslius matavimus, kurie naudojami įvertinti įvairiems parametrams, tokiems kaip dirvožemio drėgmė, augalijos danga, ledynų tirpimas ir kt. GNSS ir SAR plačiai naudojami atliekant tektoninių plokščių poslinkių ir žemės stabilumo stebėjimus. Europos žemės judesius stebinčios tarnybos sukurta sistema atliktas tyrimas Kirkilų ežeryno smegduobių teritorijoje, kurios plotas 5.9 ha. Nustatyta, kad sistema tokiame plote naudoja tik keturis matuojamus taškus, tai išsamiai neapibūdina visos vietovės aukščių pokyčių situacijos laike, todėl būtų naudinga kurti vietinį modelį arba sistemą Lietuvos teritorijai stebėti pasitelkiant tas pačias GNSS ir SAR technologijas.
Reikšminiai žodžiai: GNSS, SAR, InSAR, aplinkos tyrimai, klimato kaita, žemės stabilumo tyrimai