Vilnius Gediminas Technical University
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Concepts of Development of Alternative Travel in Autonomous Cars
No full textAutonomous car travel planning is increasingly gaining attention from scientists and professionals, who are addressing the integration of autonomous cars into the general urban transportation system. Autonomous car travel planning depends on the transport system infrastructure, the dynamic data, and their quality. The efficient development of travel depends on the development level of the Intelligent Transport Systems (ITS) and the Cooperative Intelligent Transport Systems (C-ITS). Today, most cities around the world are competing with each other to become the smartest cities possible, using and integrating the most advanced ITS and C-ITS that are available. It is clear that ITS and C-ITS are occupying an increasing share of urban transport infrastructure, so the complex challenges of ITS and C-ITS development will inevitably need to be addressed, in the near future, by integrating them into the overall urban transport system. With this in mind, the authors proposed three autonomous car travel development concepts that should become a conceptual tool in the development of ITS and C-ITS.This article belongs to the Special Issue SUMP for Cities’ Sustainable DevelopmentThis research was funded by Vilnius Gediminas Technical University
European Countries Ranking and Clustering Solution by Children’s Physical Activity and Human Development Index Using Entropy-Based Methods
Get PDFThe aim of the present study is to propose a new approach for evaluating and comparing European countries using indicators of the children physical activity and the human development index. The Global Matrix 3.0 on physical activity for children and youth and human development index data on the 18 European countries were used. MADM (multi-attribute decision making) approach was applied for this task. The criteria weights calculated by applying the weight balancing method—weight balancing indicator ranks accordance (WEBIRA). New methodology of interval entropy is proposed for determining the priority of criteria separately in each group. The novel approach of α-cuts for recursive procedure of ranking the alternatives was used. For comparison, three alternative entropy-based methods—entropy method for determining the criterion weight (EMDCW), method of criteria impact LOSs and determination of objective weights (CILOS) and integrated determination of objective criteria weights (IDOCRIW) were applied to address this MADM problem. Cluster analysis of European countries carried out using results obtained by all above methods. Comparison of the MADM methods revealed that three alternative methods assigned negligible values to whole group of criteria. Meanwhile, WEBIRA family methods performed the ranking of European countries according to the interrelation of the two groups of criteria in a balanced way. Thus, when addressing MADM tasks with two or more naturally related sets of criteria, it is appropriate to apply criteria adapted for that purpose, such as WEBIRA.This article belongs to the Special Issue Mathematical Modeling of Socio-Economic System
Gaining Insight into Violence from Gender Stereotypes and Sexist Attitudes in the Context of Tourism
No full textIt is difficult to identify, but there is a type of harassment grounded in gender stereotyping in the context of tourism. It would be useful to discover the hidden relationships between gender harassment and certain beliefs about women as travellers, tourism professionals and sex objects in the field of hospitality. Methodologically, a survey was carried out reaching a sample of ±684 units by means of a convenience sampling procedure. The measuring instruments consisted of a structured questionnaire divided into two kinds of Likert beliefs scales comprising general statements and statements related to tourism. The survey respondent data were also gathered as regards sociodemographic characteristics. This paper presents empirical evidence to identify the causal factors of gender violence by considering general and particular stereotyping in tourism. Firstly, by performing three exploratory factor analyses, three female stereotyping dimensions were labelled in the field of tourism (occupational sexism, ambivalent sexist discrimination, and sex as a commodity), as well as three general prejudices about women (dysfunctional romantic relationships, ethically challenged presumptions, and aesthetical manners conventions) and the gender harassment factor. Secondly, a linear regression analysis was carried out to demonstrate that both general stereotyping related to a broader “life” framework and sectorial prejudices in tourism cause gender harassment. Finally, this research proves that general stereotyping determines sectorial prejudices in the field of tourism. The practical implications could be to enhance gender equality and combat gender harassment by revealing unintentional and unobserved prejudices that occur in a general life setting and in the tourism sphere against women as neglected professionals, under the subtle and ambivalent condition of travellers, and even as objects of consumption
The Change in Students’ Attitude towards Favourable and Unfavourable Factors of Online Learning Environments
No full textThis article aims to present the results of a study on favourable and unfavourable factors of using online learning environments in the study process as a digital learning strategy to promote education for sustainable development. Technologies have changed traditional face-to-face classrooms through online environments to hybrid learning spaces. Personal experiences and expectations are part of these hybrid learning setups and learner-positive attitudes to such sessions could contribute to the effectiveness of hybrid learning and student satisfaction. The quasi-experiment was carried out to determine the attitude of students towards favourable and unfavourable factors of using an online learning environment (OLE) in the study process. Five groups of students studied for one semester using the flipped classroom method. The sample was made up of 106 secondary school students, selected by means of non-probability sampling. Students were given pre-test and post-test questionnaires in the beginning and at the end of the semester. Favourable factors of using an online learning environment identified by students in the beginning of the quasi-experiment were grouped in five categories: material resources/base; teacher personality; student personality, information presentation and increase of accessibility at the institutional level. As students gain more experience in using an OLE for learning, it is not technical issues and computer literacy that become important, but students’ and teachers’ attitudes and the motivation to improve and learn. At the end of the project, the participants emphasised other favourable factors: continuous uploading of materials, convenience of use and the promotion of online learning environments for studies in all subjects. The role of the teacher while using an online learning environment was highlighted. This research contributes to the improvement of teacher pedagogical competences, creating conditions for increasing student satisfaction.This article belongs to the Special Issue Sustainable Educational Management for Effective E-Learnin
Insights and Findings Following 11 Years of Test Road Exploitation
No full textRoad pavement is one of the most important components of road structure. Long-term monitoring changes in the state of road pavement under real conditions of load and climate allows to determine surface degradation mechanisms, select sustainable road building materials and their mixes, rationally employ asphalt paving technologies, and improve quality control. For a number of years, road pavement structures have been studied that should best meet the Lithuanian climate conditions and withstand the increasing impact of vehicle load. Thus, for that purpose, specially designed, constructed and tested roads or road sections for different pavement structures are most appropriate. One of those was constructed in 2007. The experimental road (hereinafter, the Test Road) consisted of 27 different pavement structures (PSs) produced of various materials. The study aims to evaluate the effect of different materials on variations in the bearing capacity of the pavement structure (PS), the sustainability of the structure, and the formation of ruts in 2007–2018. In this way, difference in bearing capacity, rutting depth between sections, and loaded and unloaded lanes was estimated. Further, the statistical analysis of these factors was conducted. Investigations have shown that the minimum bearing capacity of 754 MPa established after 11 years did not affect the formation of rut depth that was less than 1.0 cm. The PSs covered with the used asphalt granules, a larger asphalt base course on gravel, the sand mix base course, and granite aggregate mixed with sand base course were accepted as one of the PSs with the highest bearing capacity with PSs exceeding 929 MPa. The bearing capacity of the PS containing a 20 cm aggregate base course is on average higher by 30 MPa than PS holding a 15 cm aggregate base course.This article belongs to the Special Issue Pavement Surface CoatingsThis research was funded by the Lithuanian Road Administration under the Ministry of Transport and Communications fun
Comparative Study on the Energetic and Ecologic Parameters of Dual Fuels (Diesel–NG and HVO–Biogas) and Conventional Diesel Fuel in a CI Engine
No full textThe Article presents the results of the experimental research and numerical analysis of a compression ignition (CI) engine adapted for running on dual fuels of different composition (diesel and natural gas, diesel and biogas, biodiesel and natural gas, and biodiesel and biogas). The main goal was to find out the impact of different dual fuels on energy performance and emissions depending on the start of injection (SOI) of diesel and the crank angle degree (CAD). Pure conventional diesel fuel and second generation hydrotreated vegetable oil (HVO) (Neste) was used in the research. Natural gas contained 97 vol. % of methane. Biogas (biomethane) was simulated using a methane and carbon dioxide blend consisting of 60 vol. % of methane and 40 vol. % of carbon dioxide. Dual (liquid and gaseous) fuels were used in the tests, with the energy share of liquid fuels accounting for 40% and gas for 60%. The research results have shown that having replaced conventional diesel fuel with dual fuel, engine’s BTE declined by 11.9–16.5%. The use of methane in the dual fuel blend reduced CO2 volumetric fraction in the exhaust gases by 17–20%, while biomethane increased CO2 volumetric fraction by 10–14%. Dual fuel significantly increased CO and HC emissions, but NOx volumetric fraction decreased by 67–82% and smoke by 23–39%. The numerical analysis of the combustion process revealed changes in the ROHR (Rate of Heat Release) that affected engine efficiency and exhaust emissions was done by AVL (Anstalt für Verbrennungskraftmaschinen List) BOOST program.This article belongs to the Special Issue Advances in Alternative Fuel and Low Greenhouse Gas Emissions for the Internal Combustion Engine-Based Powertrain
Controller for the Grid-Connected Microinverter Output Current Tracking
No full textThe modification of the proportional–integral (PI) controller with the variable proportional constant for tracking of the grid-connected photovoltaic microinverter output current has been proposed. The obtained results show that in the case when the proportional constant of the PI controller varies in time according to the appropriate law, the microinverter output current sinus shape distortions decrease as compared to the case when the ordinary PI controller is used. The operation of the microinverter with the proposed controller was investigated for the cases when the electrical grid voltage sinus shape is not distorted and when it is distorted by the higher harmonics
Method for Attack Tree Data Transformation and Import Into IT Risk Analysis Expert Systems
Get PDFInformation technology (IT) security risk analysis preventatively helps organizations in identifying their vulnerable systems or internal controls. Some researchers propose expert systems (ES) as the solution for risk analysis automation since risk analysis by human experts is expensive and timely. By design, ES need a knowledge base, which must be up to date and of high quality. Manual creation of databases is also expensive and cannot ensure stable information renewal. These facts make the knowledge base automation process very important. This paper proposes a novel method of converting attack trees to a format usable by expert systems for utilizing the existing attack tree repositories in facilitating information and IT security risk analysis. The method performs attack tree translation into the Java Expert System Shell (JESS) format, by consistently applying ATTop, a software bridging tool that enables automated analysis of attack trees using a model-driven engineering approach, translating attack trees into the eXtensible Markup Language (XML) format, and using the newly developed ATES (attack trees to expert system) program, performing further XML conversion into JESS compatible format. The detailed method description, along with samples of attack tree conversion and results of conversion experiments on a significant number of attack trees, are presented and discussed. The results demonstrate the high method reliability rate and viability of attack trees as a source for the knowledge bases of expert systems used in the IT security risk analysis process.This article belongs to the Special Issue Human-Centered Computing and Information Security: Recent Advances & Intelligent Application
Rheological Properties and Flow Behaviour of Cement-Based Materials Modified by Carbon Nanotubes and Plasticising Admixtures
No full textIn this study, the rheological properties of cement paste modified by a suspension containing both multi-walled carbon nanotubes (MWCNT) and carboxymethyl cellulose (CMC) (MWCNT/CMC suspension) with different types of plasticising admixtures (Pl), such as lignosulphonate (LS), sulfonated naphthalene formaldehyde condensate (NF), and polycarboxylate ether (PCE) were evaluated. The increase in yield stress and plastic viscosity up to 20% was established in the case of the modification of cement-based mixtures by MWCNT in the dosage up to 0.24% by weight of cement (bwoc) without Pl and with LS and NF. The complex modification of cement paste by MWCNT and PCE increases the yield stress and plastic viscosity from the MWCNT dosage of 0.06% and 0.015% bwoc, respectively. The yield stress and plastic viscosity of cement paste with PCE enhanced by 265% and 107%, respectively, in a MWCNT dosage of 0.12% bwoc. MWCNT do not have a significant influence on the flow behaviour index of cement paste; however, in the case of usage of PCE, the shear thickening effect decreased from a MWCNT dosage of 0.03% bwoc. The significant reduction in the volume coefficient of water bleeding by 99, 100, and 83% was obtained with LS, NF, and PCE, respectively, with an increase in MWCNT dosage up to 0.24% bwoc.This article belongs to the Special Issue Flow and Heat Transfer in Non-linear FluidsThis research was funded by the Research Council of Lithuania, grant number 320165329-1
Wearable Sensors Technology as a Tool for Discriminating Frailty Levels During Instrumented Gait Analysis
No full textBackground and objectives: One of the greatest challenges facing the healthcare of the aging population is frailty. There is growing scientific evidence that gait assessment using wearable sensors could be used for prefrailty and frailty screening. The purpose of this study was to examine the ability of a wearable sensor-based assessment of gait to discriminate between frailty levels (robust, prefrail, and frail). Materials and methods: 133 participants (≥60 years) were recruited and frailty was assessed using the Fried criteria. Gait was assessed using wireless inertial sensors attached by straps on the thighs, shins, and feet. Between-group differences in frailty were assessed using analysis of variance. Associations between frailty and gait parameters were assessed using multinomial logistic models with frailty as the dependent variable. We used receiver operating characteristic (ROC) curves to calculate the area under the curve (AUC) to estimate the predictive validity of each parameter. The cut-off values were calculated based on the Youden index. Results: Frailty was identified in 37 (28%) participants, prefrailty in 66 (50%), and no Fried criteria were found in 30 (23%) participants. Gait speed, stance phase time, swing phase time, stride time, double support time, and cadence were able to discriminate frailty from robust, and prefrail from robust. Stride time (AUC = 0.915), stance phase (AUC = 0.923), and cadence (AUC = 0.930) were the most sensitive parameters to separate frail or prefrail from robust. Other gait parameters, such as double support, had poor sensitivity. We determined the value of stride time (1.19 s), stance phase time (0.68 s), and cadence (101 steps/min) to identify individuals with prefrailty or frailty with sufficient sensitivity and specificity. Conclusions: The results of our study show that gait analysis using wearable sensors could discriminate between frailty levels. We were able to identify several gait indicators apart from gait speed that distinguish frail or prefrail from robust with sufficient sensitivity and specificity. If improved and adapted for everyday use, gait assessment technologies could contribute to frailty screening and monitoring.This article belongs to the Section Applied Biosciences and Bioengineerin