The journey of demand responsive transportation: Towards sustainable services

The concept of Demand Responsive Transport (DRT) describes a technology-enabled shared mobility service that has a flexible operating schedule and/or provides virtual stops and/or flexible routes. While these on-demand services are not new, the developments in communication and tracking technology (vehicle positioning systems) have revived these services in the past decade. The benefits of adopting demand responsive transport services for intra-community and FLM travel needs are widely accepted, but there is still a cautious approach towards their implementation due to the failure of many promising demand responsive transport schemes in the past. This article 1) creates an overview of the various on-demand services introduced across the world, to understand the factors that may have contributed to the failure of these services in the past 2) identifies the progress made towards sustainable demand responsive transport ventures through analysis of global case studies 3) provides an overview of the flexibility of vehicle and deployment technologies in the demand responsive transport sphere. A bibliometric analysis, where the top keywords were further categorised using VOSviewer’s default clustering algorithm, highlighted the importance of sustainability in demand responsive transport ventures. By the progress made towards sustainable demand responsive transport ventures, it can be concluded that environmentally sustainable demand responsive transport ventures can be achieved through the adoption of electric and autonomous vehicles for demand responsive transport services, by reducing mileage of the vehicle and/or adjusting the length of route. The study concludes by reviewing existing research gaps regarding performance expectation, and recommending policy and practice implications, based on the case study of the Bus-on-Demand in Dubai, UAE

Gender Mainstreaming and Impact of Self-Help Groups: A Study on Social Entrepreneurship through Fish Aggregating Devices in Mannancheri of Alappuzha, Kerala

A research study for assessing the impact of fisher folk Self Help Groups in gender mainstreaming was undertaken on social entrepreneurship venture on fish aggregating devices at Mannancheri gramapanchayath, located at Alappuzha district of Kerala. The analysis included specific aspects such as performance assessment of the SHGs, gender analysis and empowerment analysis which were carried out based on socio-economic surveys and personal interviews using pre-tested and structured data gathering protocols with standardized scales and indices involving the members of the SHGs. The male and female counterparts of the families were separately interviewed to assess the gender mainstreaming aspects in terms of equity and equality to access to resources, participation profile, decision making aspects, gender need analysis etc. Though majority of activities are male dominated, the female counterparts of the households also have definite role in decision making, purchase of accessories etc. A success case study was elucidated and documented as a documentary which can be used as a case model for promoting group action for mobilizing SHGs on a sustainable basis

Is self help group approach a means for gender mainstreaming? A study on dry fish units in Ramanathapuram district, Tamil Nadu

A study to assess the impact of SHGs in gender mainstreaming was undertaken among the SHG operating dry fish units at Ramanathapuram district of Tamil Nadu. The analysis included performance assessment of the SHGs, gender analysis, empowerment analysis and economic feasibility analysis which were carried out based on the primary data collected from the members of the SHGs. The male and female counterparts of the families of SHG members were separately interviewed to assess the gender mainstreaming aspects in terms of equity and equality to access to resources, participation profile, decision making aspects, gender need analysis etc. Though majority of activities are female dominated, the male counterparts of the households also have definite role in decision making, purchase of accessories, sales, marketing etc. The indicative economics worked out for the economic feasibility analysis of the SHGs suggests that, the unit takes just one year to achieve break even. A case studywas documented as amoviewhich can be used as a case model for promoting group actionby mobilizingSHGsona sustainable basis

Is self help group approach a means for gender mainstreaming? A study on dry fish units in Ramanathapuram district, Tamil Nadu

A study to assess the impact of SHGs in gender mainstreaming was undertaken among the SHG operating dry fish units at Ramanathapuram district of Tamil Nadu. The analysis included performance assessment of the SHGs, gender analysis, empowerment analysis and economic feasibility analysis which were carried out based on the primary data collected from the members of the SHGs. The male and female counterparts of the families of SHG members were separately interviewed to assess the gender mainstreaming aspects in terms of equity and equality to access to resources, participation profile, decision making aspects, gender need analysis etc. Though majority of activities are female dominated, the male counterparts of the households also have definite role in decision making, purchase of accessories, sales, marketing etc. The indicative economics worked out for the economic feasibility analysis of the SHGs suggests that, the unit takes just one year to achieve break even. A case studywas documented as amoviewhich can be used as a case model for promoting group actionby mobilizingSHGsona sustainable basis

Influence of Spatial Variability on Pavement Responses Using Latin Hypercube Sampling on Two-Dimensional Random Fields

Although uncertainties in material properties have been addressed in the design of flexible pavements, most current modeling techniques assume that pavement layers are homogeneous. The paper addresses the influence of the spatial variability of the resilient moduli of pavement layers by evaluating the effect of the variance and correlation length on the pavement responses to loading. The integration of the spatially varying log-normal random field with the finite-difference method has been achieved through an exponential autocorrelation function. The variation in the correlation length was found to have a marginal effect on the mean values of the critical strains and a noticeable effect on the standard deviation which decreases with decreases in correlation length. This reduction in the variance arises because of the spatial averaging phenomenon over the softer and stiffer zones generated because of spatial variability. The increase in the mean value of critical strains with decreasing correlation length, although minor, illustrates that pavement performance is adversely affected by the presence of spatially varying layers. The study also confirmed that the higher the variability in the pavement layer moduli, introduced through a higher value of coefficient of variation (COV), the higher the variability in the pavement response. The study concludes that ignoring spatial variability by modeling the pavement layers as homogeneous that have very short correlation lengths can result in the underestimation of the critical strains and thus an inaccurate assessment of the pavement performance. (C) 2014 American Society of Civil Engineers

System Reliability Analysis of Flexible Pavements

The uncertainty in material properties and traffic characterization in the design of flexible pavements has led to significant efforts in recent years to incorporate reliability methods and probabilistic design procedures for the design, rehabilitation, and maintenance of pavements. In the mechanistic-empirical (ME) design of pavements, despite the fact that there are multiple failure modes, the design criteria applied in the majority of analytical pavement design methods guard only against fatigue cracking and subgrade rutting, which are usually considered as independent failure events. This study carries out the reliability analysis for a flexible pavement section for these failure criteria based on the first-order reliability method (FORM) and the second-order reliability method (SORM) techniques and the crude Monte Carlo simulation. Through a sensitivity analysis, the most critical parameter affecting the design reliability for both fatigue and rutting failure criteria was identified as the surface layer thickness. However, reliability analysis in pavement design is most useful if it can be efficiently and accurately applied to components of pavement design and the combination of these components in an overall system analysis. The study shows that for the pavement section considered, there is a high degree of dependence between the two failure modes, and demonstrates that the probability of simultaneous occurrence of failures can be almost as high as the probability of component failures. Thus, the need to consider the system reliability in the pavement analysis is highlighted, and the study indicates that the improvement of pavement performance should be tackled in the light of reducing this undesirable event of simultaneous failure and not merely the consideration of the more critical failure mode. Furthermore, this probability of simultaneous occurrence of failures is seen to increase considerably with small increments in the mean traffic loads, which also results in wider system reliability bounds. The study also advocates the use of narrow bounds to the probability of failure, which provides a better estimate of the probability of failure, as validated from the results obtained from Monte Carlo simulation (MCS)

Time-Dependent Reliability Analysis of the Contaminant Migration of Radioactive Waste in Groundwater

Nuclear power is an efficient source of power generation with low carbon emissions. But one of the serious problems encountered in the nuclear industry is the development of proper disposal facilities for radioactive waste. The safety of a waste disposal facility depends on the efficiency of its design against contaminant migration. The transport mechanisms of the contaminant are complex processes which involves advection, diffusion and dispersion considering radioactive decay. The heterogeneity of the aquifers and the existence of uncertainty (data and model uncertainty) affect greatly the predictive ability of groundwater flow and contaminant transport models. As a result, in a complex structural system like a near surface disposal facility (NSDF) where low and intermediate level wastes are disposed, the amount of radionuclide released into groundwater post closure is a major concern for the design. It is essential to know the probability of the concentration of radionuclide in the drinking water pathway exceeding the permissible value (probability of failure). Further, the long timescales considered in NSDF are a key feature making treatment of uncertainties more challenging and since the parameters influencing the contaminant process evolve in time, there is a need for a time dependent reliability analysis in this regard. In the present study, the contaminant migration is modelled as a convolution of the repository failure and the transport of the contaminant to groundwater through advection and dispersion. The uncertainties are modelled by considering variability in parameters and the time dependent probability of failure is estimated using Monte Carlo simulations

Evaluation of Flexible Pavement Distress Using Nonlinear Regression Analysis

The current study aims at developing well-predicting regression equations for evaluating the fatigue and rutting strains at critical locations within the flexible pavement layers. With an objective to develop unified regression models, the practical on-field ranges for thickness and layer moduli of various pavement layers are used in the analysis. These design input combinations are fed into a multilayer elastic analysis program using an automation technique to reduce a lot of human effort and evaluation time. The output obtained from the program is used to develop equations for fatigue and rutting strains by nonlinear regression analysis. The outcomes of this study will aid the design engineers as well as researchers in multiple ways. In addition to the advantages in pavement design, the automation procedure combined with regression would also aid the researchers in simulation studies, reliability analysis, etc