Faculty Publications
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Item Groundwater quality assessment of urban Bengaluru using multivariate statistical techniques(Springer Verlag, 2018) Gulgundi, M.S.; Shetty, A.Groundwater quality deterioration due to anthropogenic activities has become a subject of prime concern. The objective of the study was to assess the spatial and temporal variations in groundwater quality and to identify the sources in the western half of the Bengaluru city using multivariate statistical techniques. Water quality index rating was calculated for pre and post monsoon seasons to quantify overall water quality for human consumption. The post-monsoon samples show signs of poor quality in drinking purpose compared to pre-monsoon. Cluster analysis (CA), principal component analysis (PCA) and discriminant analysis (DA) were applied to the groundwater quality data measured on 14 parameters from 67 sites distributed across the city. Hierarchical cluster analysis (CA) grouped the 67 sampling stations into two groups, cluster 1 having high pollution and cluster 2 having lesser pollution. Discriminant analysis (DA) was applied to delineate the most meaningful parameters accounting for temporal and spatial variations in groundwater quality of the study area. Temporal DA identified pH as the most important parameter, which discriminates between water quality in the pre-monsoon and post-monsoon seasons and accounts for 72% seasonal assignation of cases. Spatial DA identified Mg, Cl and NO3 as the three most important parameters discriminating between two clusters and accounting for 89% spatial assignation of cases. Principal component analysis was applied to the dataset obtained from the two clusters, which evolved three factors in each cluster, explaining 85.4 and 84% of the total variance, respectively. Varifactors obtained from principal component analysis showed that groundwater quality variation is mainly explained by dissolution of minerals from rock water interactions in the aquifer, effect of anthropogenic activities and ion exchange processes in water. © 2018, The Author(s).Item Modelling personal safety perceptions at bus stop: employing hierarchical confirmatory factor analysis and structural equation approach(Aracne Editrice, 2023) Sethulakshm, G.; Mohan, M.Vehicle-pedestrian interactions occurring within a limited space are quite common at bus stops, making it essential to comprehend passengers' perception of safety near bus stops. Since the sense of perceived safety is subjective, developing a standardized tool to measure travellers' perception of safety, especially of bus users, is complex. The first part of this study aims to identify the indicators for measuring the perceived safety at bus stops, and the second part focuses on modelling the overall perceived safety of users’ at bus stops using structural equation modelling. The research examined the safety factors according to 14 indicators which were further reduced to five latent constructs using exploratory factor analysis. Perceived safety is taken as a second-order latent construct, and the second-order confirmatory factor analysis found that safety derived from five latent variables, namely bus stop facility, bus stop location, bus operator behaviour, other users' behaviour, and pedestrian facility, are potential indicators of overall perceived safety at the bus stop. The results recommend that providing night light facilities, adopting measures to avoid improper stopping of buses and left-side overtaking, avoiding bus stops on curves and junctions, and ensuring better sidewalk facilities could improve perceived safety. Structural equation modelling revealed that safety perceptions are negatively influenced by previous accident victimization and witnessing, age, educational qualification and total household vehicles. The results conclude that female respondents perceive less safety than males, and no effects can be attributed to the frequency of travel and trip length. The research findings will be helpful for the planning agencies to prioritize measures to improve travellers' feeling of safety. © 2023, Aracne Editrice. All rights reserved.Item Designing safe and accessible bus stops: an exploration of the interplay between perceived safety at crosswalk and transit ridership(Routledge, 2025) Sethulakshmi, G.; Mohan, M.Measuring personal safety perception is inherently complex, involving a multifaceted array of factors. This research advances the field of knowledge by developing a novel factor structure to assess pedestrian safety perceptions and modelling overall safety as a latent construct through a second-order Confirmatory Factor Analysis. Data were collected from 568 pedestrian interviews on safety perceptions near bus stops. The study concluded that perceived safety can be measured using four latent constructs: crosswalk infrastructure, crossing environment, management measures, and driver behavior, which collectively contribute to overall crosswalk safety. Using Structural Equation Modelling, the study confirms that as perceived safety while accessing bus stops via crosswalks decreases, bus ridership also declines. Findings also reveal demographic differences, with women, older individuals, and prior accident victims perceiving bus stop environments as less safe. Results suggest that policymakers should prioritize dedicated crosswalks and control speed and aggressive driving to maximize perceived safety at bus stops. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Modelling sidewalk safety perceptions of pedestrians accessing bus stops and uncovering its role in shaping bus ridership: An empirical investigation(Elsevier Ltd, 2025) Sethulakshmi, G.; Mohan, M.Measuring personal safety perception is a complex task, as it encompasses a multi-faceted array of factors. This study explores the factors influencing the perceived safety of pedestrians while accessing bus stops via sidewalks and develops a comprehensive measurement model for sidewalk safety perception. Additionally, the study investigates potential links between sidewalk safety perceptions and bus ridership by applying Structural Equation Modelling (SEM). Data were collected from 568 personal interviews conducted across various Indian cities, focusing on pedestrians’ perceptions of safety while accessing bus stops. Perceived safety was conceptualized as a latent construct, with second-order confirmatory factor analysis identifying three primary dimensions: “Safety from Sidewalk Infrastructure”, “Safety from Other User Behavior” and “Safety from Sidewalk Maintenance and Management”. These three latent constructs collectively represent the overall safety perception of sidewalks in the context of bus stop access. Further analysis found that most bus users prefer a minimum sidewalk width of 1.5–2 m and an increased minimum width of 2–4 m near bus stops. The findings offer valuable insights into the intricate factors shaping pedestrian safety perceptions and provide a robust framework for enhancing sidewalk conditions to promote safer and more accessible public transit usage. © 2025 Elsevier Ltd