25 research outputs found
Validation of a Pedestrian Simulator for interaction between Pedestrians and Autonomous Vehicles
No full textA large number of pedestrian fatalities and the emergence of autonomous vehicles (AVs) creates a need for research in vehicle to pedestrian (V2P) interaction. Gestures (e.g., hand movement, eye contact) used for communication between pedestrians and manually driven vehicle plays a significant role to reduce ambiguities and make safe road crossing decisions. With autonomous vehicles on the roads in the near future, it may be possible that pedestrians are not able to understand the vehicle behaviour or vice a versa. Virtual reality (VR) simulations are used to test a new method of communications such as external human-machine interface (eHMI) between AVs and pedestrians. Virtual reality has emerged as an effective and cost-efficient tool in various fields such as surgical training, technician training and driver simulators. Among many benefits of virtual reality, is it’s ability to expose its users to critical situations where the real environment would be dangerous and therefore, could be a viable tool for conducting V2P research. However, it is essential to understand how pedestrians’ behaviour and perception match in VR or 360◦ video with real life to rely on themas an experimental method. The main goal of this study was to examine the effectiveness of VR and 360-degree video environments in terms of pedestrian perception and behaviour to draw actionable conclusions on the reliability of VR.An experiment was conducted to test the interaction between pedestrians and autonomous vehicles using three different environments: a field test on a a public road, a replication of the test in an animated virtual reality (VR) simulation and a third repetition using a 360-degree video recording of the same location. The animated virtual environment was designed using Unity and C#, and the 360-degree videos were recorded at the field test location from participants’ position at a height of 180 cm. The participant was standing on the sidewalk on a two-lane road in Delft in each environment. To compare human perception of distance and speed and behaviour in terms of gap accepted during road crossing scenarios in 360-degree video and animated VR, three tasks being: 1) Distance estimation, 2) Speed estimation and 3) Gap acceptance was conducted in each environment with a within-subject design (N = 30). Results showed that there were no significant differences between the three environments for distance estimation, gap acceptance tasks and measures of presence. However, significant differences were found between animated VR and 360-degree video environment for perceived speed of 30 km/h. According to the median values, the perceived distance in real life and animated virtual environment deviated below 5% from the ground truth values. However, the median values for perceived distance in 360-degree video environment fordistances of 40 m and 63 m were overestimated. The deviation in perceived distance increased as the ground truth value increased, wherein the animated virtual environment showed the highest amount of variance amongst the three environments. Underestimation of the speed of about 5 - 10 km/h was observed in both field tests and animated virtual environment for speeds below 50 km/h. The median values show that the perceived speed was most accurate in a 360-degree video environment. However, the animated virtual environment was more consistent with real life perceived speed. A significant positive correlation between distance and speed estimates showed consistency in human perception across the three environments. A negative correlation was found between perceived distance and gap acceptance ratio, whereas a positive correlation was found between perceived speed and gap acceptance ratio. The presence scores were relatively higher for field tests and 360-degree video environments compared to the animated virtual environment. However, the scores were high enough to validate the three environments subjectively. Only one participant experience motionsickness in virtual reality tasks with a score of above 2 out of 3, experiencing a moderate sickness but was successfully able to complete the whole experimental task. Overall results show that pedestrian perception and behaviour in 360-degree video and animated VR environment doesn’t differ significantly from real life. These results have a strong implication on the usage of virtual environments for studying pedestrians’ perception and behaviour when interacting with vehicles.Mechanical Engineering | Vehicle Engineerin
Deposition and characterization of vanadium oxide based thin films for MOS device applications
No full textOptical, electrical properties and structural characterization of ZnO:rGO based photodetector
No full textOn I-statistically rough convergence
No full textWe introduce rough I-statistical convergence as an extension of rough convergence. We define the set of rough I-statistical limit points of a sequence and analyze the results with proofs. © 2019, Mathematical Institute of the Serbian Academy of Sciences and Arts.Council for Scientific and Industrial Research, South Africa: 25(0236)/14/EMR-II Bangladesh Council of Scientific and Industrial Research -- The second author is grateful to Council of Scientific and Industrial Research, INDIA for financial support required to carry out this research work through the CSIR Project No. 25(0236)/14/EMR-II. -- -
Inference in high dimensional regression
No full textThis thesis proposes a novel statistical inference framework for high-dimensional generalized linear models (GLMs). The first project focuses on labeling patients in electronic health records as case or control using high-dimensional sparse logistic regression models. A lack of valid statistical inference methods for the case probability poses a major hurdle. To address this, the project proposes a novel bias-corrected estimator for the case probability and establishes its asymptotic normality. The second project considers high-dimensional sparse Poisson regression models and proposes bias-corrected estimators for linear and quadratic transformations of the high-dimensional regression vector. We apply the devised methodology to the high-dimensional mediation analysis, with a particular application of testing the interaction between the treatment variable and high-dimensional mediators. The third project presents the R package SIHR on statistical inferences in high-dimensional generalized linear models for continuous and binary outcomes. The package includes confidence interval construction and hypothesis testing for linear and quadratic functionals and demonstrates practical applications in both numerical examples and real data settings.Ph.D.Includes bibliographical reference
INTERNATIONAL MIGRATION OF SKILLED AND UNSKILLED LABOUR, WELFARE AND SKILLED-UNSKILLED WAGE INEQUALITY: A SIMPLE MODEL
No full textThe paper shows that in a reasonable production structure for a developing economy a brain drain of skilled labour may raise the welfare of the economy while an emigration of unskilled labour is welfare reducing. Also an emigration of skilled / unskilled labour lowers the urban unemployment of unskilled labour and widens the skilled-unskilled wage-gap. The paper provides an alternative explanation for the increasing wage inequality in many less developed countries in the regime of liberalized trade and investment in terms of higher international mobility of skilled and unskilled labour during this period using a Harris-Todaro (1970) framework where the central principle of the Stolper-Samuelson theorem holds.Skilled labour, Unskilled labour, Emigration of labour, Welfare, Urban unemployment, Skilled-unskilled wage gap
Social media and the new product development during COVID-19: An integrated model for SMEs
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordDespite Multinational Enterprises’ growing interest in New Product Development (NPD), research into the
use of social media in the NPD process in Small and Medium-sized Enterprises (SMEs) is lacking. In
response, we propose and test an integrated model of the NPD process using social media. Data was
collected from SMEs across industry sectors in India during the COVID-19 pandemic. This research applies
structural equation modeling (SEM) to achieve a detailed understanding of the issue. The findings reveal
that Integrated Social Media Interaction (ISMI) depends on Customer-Centric Focus (CCF), Customer
Engagement Focus (CEF), and Customer Empathy Focus (CEmF). Based on the literature and our
analytical research, it is revealed that the use of social media networks as a source of knowledge for NPD
ventures is a systematic component of the NPD process for SMEs during the COVOD-19 pandemic. To
support their NPD initiatives, SMEs may depend on this hypothesized integrated model. The analysis
concludes with SME managers' realistic and managerial guidance. This study provides useful insights for
managers who wish to enhance NPD activities for SMEs through social media, and offers useful guidance
to SMEs and innovation scholars, encouraging further research in this area
Modified SIR model for COVID-19 transmission dynamics: Simulation with case study of UK, US and India
No full textCorona virus disease 2019 (COVID-19) is an infectious disease and has spread over more than 200 countries since its outbreak in December 2019. This pandemic has posed the greatest threat to global public health and seems to have changing characteristics with altering variants, hence various epidemiological and statistical models are getting developed to predict the infection spread, mortality rate and calibrating various impacting factors. But the aysmptomatic patient counts and demographical factors needs to be considered in model evaluation. Here we have proposed a new seven compartmental model, Susceptible- Exposed- Infected–Asymptomatic–Quarantined–Fatal–Recovered (SEIAQFR) which is based on classical Susceptible-Infected-Recovered (SIR) model dynamic of infectious disease, and considered factors like asymptomatic transmission and quarantine of patients. We have taken UK, US and India as a case study for model evaluation purpose. In our analysis, it is found that the Reproductive Rate ([Formula: see text]) of the disease is dynamic over a long period and provides better results in model performance ([Formula: see text] R-square score) when model is fitted across smaller time period. On an average [Formula: see text] cases are asymptomatic and have contributed to model accuracy. The model is employed to show accuracy in correspondence with different geographic data in both wave of disease spread. Different disease spreading factors like infection rate, recovery rate and mortality rate are well analyzed with best fit of real world data. Performance evaluation of this model has achieved good R-Square score which is [Formula: see text] for infection prediction and [Formula: see text] for death prediction and an average [Formula: see text] MAPE in different wave of the disease in UK, US and India
Mobile apps for SME business sustainability during COVID-19 and onwards
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Small and Medium-Sized Enterprises (SMEs) are struggling to cope with the business uncertainty caused by the COVID-19 pandemic. This study examines how SMEs in developing economies have used mobile apps to improve their business efficiency during the pandemic. We aim to recognize effective measures and actions taken by SMEs that have turned to mobile-app-based business to improve their sustainability during the crisis. The study bridges a literature gap by extending the Theory of Consumption Values and the Theory of Planned Behavior to SMEs that incorporate mobile-app-based business. Data was collected from 343 SMEs from three Industrial Development Corporations (IDCs) in India. Using the covariance-based structural equation modeling method, we investigated the efficiency of a conceptual model of mobile-app-based business for SMEs. The results revealed that consumer choice behavior, perceived behavior control, subjective behavior control and attitude towards the mobile app all influence SMEs’ decision-making and business strategy. As such, SMEs need a powerful mobile-app-based business network to succeed in the entrepreneurial business process. Using instrumental variable analysis, we discovered that increased mobile app usage significantly improves SMEs’ long-term efficiency. The analysis provides several theoretical and managerial ramifications
