Application of analytic hierarchy process to prioritize urban transport options: Comparative analysis of group aggregation methods

The present study presents a comparative analysis of different group aggregation methods adopted in AHP by testing them against social choice axioms with a case study of Delhi transport system. The group aggregation (GA) methods and their correctness were tested while prioritizing the alternative options to achieve energy efficient and less polluting transport system in Delhi. It was observed that among all group aggregation methods, geometric mean method (GMM) - the most widely adopted GA method of AHP - showed poor performance and failed to satisfy the most popular "pareto optimality and non-dictatorship axiom" raising questions on its validity as GA method adopted in AHP. All other group aggregation methods viz. weighted arithmetic mean method with varying weights and equal weights (WAMM, WeAMM) and arithmetic mean of individual priorities (AMM) resulted in concurring results with the individual member priorities. This study demonstrates that WeAMM resulted in better aggregation of individual priorities compared to WAMM. Comparative analysis between individual and group priorities demonstrates that the arithmetic mean (AMM) of priorities by individual members of the group showed minimum deviation from the group consensus making it the most suitable and simple method to aggregate individual preferences to arrive at a group consensus.AHP, decision making, GMM, group aggregation, transportation, WAMM

Prioritization of Strategies to Overcome Barriers for Cleaner and Energy Efficient Alternatives in Urban Transportation - Multi-criteria Approach

Adoption of cleaner and energy efficient technologies (CEETs) in urban transport experiences certain barriers and deriving a set of policies to remove/reduce barrier in the case of Delhi and Mumbai transport systems was attempted in this study. A set of policy alternatives and measures (PAMs) were identified for each barrier and a pool of barriers PAMs for all barriers were identified which were finally analysed for their potential based on 4 important criteria namely administrative costs, financial burden, human resource benefits, administrative backup and political acceptability. Based on aggregated multi-criteria assessment, the policy of distinct colouring scheme for alternate fuel vehicles (AFVs) stood first followed by awareness campaigns to the drivers, training programs to the workers, single window/priority check points, financial incentives and task force to carry out check. To realize the completeness, potential of PAMs in handling barriers was analysed considering not only a set of criteria but also their potential in handling more than one barrier. In overall ranking, policy to develop partnerships among major stakeholders and awareness campaigns to the drivers showed highest potential in removing barriers for the adoption of CEETs. Based on the ranking under both approaches a set of seven policy measures and alternatives were selected to remove barriers to CEETS and they are partnership between the Government, public sector undertakings and private actors in proving better infrastructure; Financial incentives like free or priority parking, separate lanes for alternative fuel vehicles and free inspection and maintenance; Task force to carry our checks; Heavy fines on defaulters; Distinct colour coding for AFVs; Demonstration of AFVs and their advantages; and Awareness campaigns to drivers. This set of PAMs would be able to control all seven pre-identified barriers to the adoption of CEETs in Delhi and Mumbai urban transportation systems.Barriers, CEETs, multi-criteria, policy analysis, urban transport

Application of Analytic Hierarchy Process to Prioritize Urban Transport Options - Comparative Analysis of Group Aggregation Methods

The present study presents a comparative analysis of different group aggregation methods adopted in AHP by testing them against social choice axioms with a case study of Delhi transport system. The group aggregation (GA) methods and their correctness were tested while prioritizing the alternative options to achieve energy efficient and less polluting transport system in Delhi It was observed that among all group aggregation methods, geometric mean method (GMM) - the most widely adopted GA method of AHP - showed poor performance and failed to satisfy the most popular pareto optimality and non-dictatorship axiom raising questions on its validity as GA method adopted in AHP. All other group aggregation methods viz. weighted arithmetic mean method with varying weights and equal weights (WAMM, WeAMM) and arithmetic mean of individual priorities (AMM) resulted in concurring results with the individual member priorities. This study demonstrates that WeAMM resulted in better aggregation of individual priorities compared to WAMM. Comparative analysis between individual and group priorities demonstrates that the arithmetic mean (AMM) of priorities by individual members of the group showed minimum deviation from the group consensus making it the most suitable and simple method to aggregate individual preferences to arrive at a group consensus.AHP, decision making, GMM, group aggregation, transportation, WAMM

Design and Analysis of Combined Extrusion Forging Die Behavior Under Thermal Structural Loads

We all know extrusion and forging are two different processes of manufacturing but in recent past researches combined these two process to reduce the production time, production cost etc.Combined extrusion-forging processes are now getting importance for its abilities to give improved material properties, high production rate and less material waste when compared with that produced by machining, casting or by assembling the individual parts produced by different manufacturing processes. In its simplest form of combined extrusion forging process, a billet is forged by punch and dies with punch/die or both containing an opening for extrusion. This tooling arrangement permits the simultaneous lateral spread due to forging, and backward/forward extrusion or both forward and backward extrusion simultaneously through the die/punch opening(s). In this study we are going to develop a die for extrusion-forging using knowledge from previous journals and books, we will develop a die for a flange with pipe using CAD and CAE packages. A basic die is designed and tested at maximum working conditions under thermal structural loads in simulation software ANSYS and the design of the die is further improvised to minimize the stress and improve life based on safety factor issues

An integrated MCDM approach to evaluate public transportation systems in Tehran

Public transportation is one of the most important systems in transportation, especially in big and crowded cities. As a result, evaluation of public transportation systems is a strategic decision-making problem for both private and public sections. In this paper, the problem of public transportation passengers in Tehran is addressed and their satisfaction levels are assessed by using passenger satisfaction survey. An integrated MCDM approach is proposed for evaluation of public transportation systems based on Delphi method, group analytic hierarchy process (GAHP) and preference ranking organization method for enrichment of evaluations (PROMETHEE). The proposed model provides more reliable and realistic results and introduces directions for future improvements of public transportation service quality. A sensitivity analysis is applied to investigate the influence of criteria weights on the decision making problem. As a conclusion, the most important public transportation systems in Tehran orderly are: metro, taxi, BRT, bus and van. Therefore, Tehran Municipality and policy makers should encourage and support the previously mentioned systems

Radial evolution of the April 2020 stealth coronal mass ejection between 0.8 and 1 AU - Comparison of Forbush decreases at Solar Orbiter and near the Earth

Aims. We present observations of the first coronal mass ejection (CME) observed at the Solar Orbiter spacecraft on April 19, 2020, and the associated Forbush decrease (FD) measured by its High Energy Telescope (HET). This CME is a multispacecraft event also seen near Earth the next day. Methods. We highlight the capabilities of HET for observing small short-term variations of the galactic cosmic ray count rate using its single detector counters. The analytical ForbMod model is applied to the FD measurements to reproduce the Forbush decrease at both locations. Input parameters for the model are derived from both in situ and remote-sensing observations of the CME. Results. The very slow (~350 km/s) stealth CME caused a FD with an amplitude of 3 % in the low-energy cosmic ray measurements at HET and 2 % in a comparable channel of the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter, as well as a 1 % decrease in neutron monitor measurements. Significant differences are observed in the expansion behavior of the CME at different locations, which may be related to influence of the following high speed solar wind stream. Under certain assumptions, ForbMod is able to reproduce the observed FDs in low-energy cosmic ray measurements from HET as well as CRaTER, but with the same input parameters, the results do not agree with the FD amplitudes at higher energies measured by neutron monitors on Earth. We study these discrepancies and provide possible explanations. Conclusions. This study highlights that the novel measurements of the Solar Orbiter can be coordinated with other spacecraft to improve our understanding of space weather in the inner heliosphere. Multi-spacecraft observations combined with data-based modeling are also essential to understand the propagation and evolution of CMEs as well as their space weather impacts

First year of energetic particle measurements in the inner heliosphere with Solar Orbiter's Energetic Particle Detector

Context. Solar Orbiter strives to unveil how the Sun controls and shapes the heliosphere and fills it with energetic particle radiation. To this end, its Energetic Particle Detector (EPD) has now been in operation, providing excellent data, for just over a year. Aims. EPD measures suprathermal and energetic particles in the energy range from a few keV up to (near-) relativistic energies (few MeV for electrons and about 500 MeV nuc−1 for ions). We present an overview of the initial results from the first year of operations and we provide a first assessment of issues and limitations. In addition, we present areas where EPD excels and provides opportunities for significant scientific progress in understanding how our Sun shapes the heliosphere. Methods. We used the solar particle events observed by Solar Orbiter on 21 July and between 10 and 11 December 2020 to discuss the capabilities, along with updates and open issues related to EPD on Solar Orbiter. We also give some words of caution and caveats related to the use of EPD-derived data. Results. During this first year of operations of the Solar Orbiter mission, EPD has recorded several particle events at distances between 0.5 and 1 au from the Sun. We present dynamic and time-averaged energy spectra for ions that were measured with a combination of all four EPD sensors, namely: the SupraThermal Electron and Proton sensor (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), and the High-Energy Telescope (HET) as well as the associated energy spectra for electrons measured with STEP and EPT. We illustrate the capabilities of the EPD suite using the 10 and 11 December 2020 solar particle event. This event showed an enrichment of heavy ions as well as 3He, for which we also present dynamic spectra measured with SIS. The high anisotropy of electrons at the onset of the event and its temporal evolution is also shown using data from these sensors. We discuss the ongoing in-flight calibration and a few open instrumental issues using data from the 21 July and the 10 and 11 December 2020 events and give guidelines and examples for the usage of the EPD data. We explain how spacecraft operations may affect EPD data and we present a list of such time periods in the appendix. A list of the most significant particle enhancements as observed by EPT during this first year is also provided.Ministerio de Economía y CompetitividadAgencia Estatal de Investigació

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (. 1 AU) heliosphere. Relativistic electrons as well as protons with energies > 50 MeV were observed by Solar Orbiter (SolO), Parker Solar Probe (PSP), the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near-Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection (CME) and an extreme ultraviolet (EUV) wave as well as a type II radio burst and multiple type III radio bursts. Aims. We present multi-spacecraft particle observations and place them in context with source observations from remote sensing instruments and discuss how such observations may further our understanding of particle acceleration and transport in this widespread event. Methods. Velocity dispersion analysis (VDA) and time shift analysis (TSA) were used to infer the particle release times at the Sun. Solar wind plasma and magnetic field measurements were examined to identify structures that influence the properties of the energetic particles such as their intensity. Pitch angle distributions and first-order anisotropies were analyzed in order to characterize the particle propagation in the interplanetary medium. Results. We find that during the 2020 November 29 SEP event, particles spread over more than 230° in longitude close to 1 AU. The particle onset delays observed at the different spacecraft are larger as the flare–footpoint angle increases and are consistent with those from previous STEREO observations. Comparing the timing when the EUV wave intersects the estimated magnetic footpoints of each spacecraft with particle release times from TSA and VDA, we conclude that a simple scenario where the particle release is only determined by the EUV wave propagation is unlikely for this event. Observations of anisotropic particle distributions at SolO, Wind, and STEREO-A do not rule out that particles are injected over a wide longitudinal range close to the Sun. However, the low values of the first-order anisotropy observed by near-Earth spacecraft suggest that diffusive propagation processes are likely involve

The first widespread solar energetic particle event observed by Solar Orbiter on 2020 November 29

Context. On 2020 November 29, the first widespread solar energetic particle (SEP) event of solar cycle 25 was observed at four widely separated locations in the inner (less than or similar to 1AU) heliosphere. Relativistic electrons as well as protons with energies >50MeV were observed by Solar Orbiter (SolO), Parker Solar Probe, the Solar Terrestrial Relations Observatory (STEREO)-A and multiple near-Earth spacecraft. The SEP event was associated with an M4.4 class X-ray flare and accompanied by a coronal mass ejection and an extreme ultraviolet (EUV) wave as well as a type II radio burst and multiple type III radio bursts.Aims. We present multi-spacecraft particle observations and place them in context with source observations from remote sensing instruments and discuss how such observations may further our understanding of particle acceleration and transport in this widespread event.Methods. Velocity dispersion analysis (VDA) and time shift analysis (TSA) were used to infer the particle release times at the Sun. Solar wind plasma and magnetic field measurements were examined to identify structures that influence the properties of the energetic particles such as their intensity. Pitch angle distributions and first-order anisotropies were analyzed in order to characterize the particle propagation in the interplanetary medium.Results. We find that during the 2020 November 29 SEP event, particles spread over more than 230 degrees in longitude close to 1AU. The particle onset delays observed at the different spacecraft are larger as the flare-footpoint angle increases and are consistent with those from previous STEREO observations. Comparing the timing when the EUV wave intersects the estimated magnetic footpoints of each spacecraft with particle release times from TSA and VDA, we conclude that a simple scenario where the particle release is only determined by the EUV wave propagation is unlikely for this event. Observations of anisotropic particle distributions at SolO, Wind, and STEREO-A do not rule out that particles are injected over a wide longitudinal range close to the Sun. However, the low values of the first-order anisotropy observed by near-Earth spacecraft suggest that di ffusive propagation processes are likely involved.</p

First near-relativistic solar electron events observed by EPD onboard Solar Orbiter

Context. Solar Orbiter, launched in February 2020, started its cruise phase in June 2020, in coincidence with its first perihelion at 0.51 au from the Sun. The in situ instruments onboard, including the Energetic Particle Detector (EPD), operate continuously during the cruise phase enabling the observation of solar energetic particles. Aims. In situ measurements of the first near-relativistic solar electron events observed in July 2020 by EPD are analyzed and the solar origins and the conditions for the interplanetary transport of these particles investigated. Methods. Electron observations from keV energies to the near-relativistic range were combined with the detection of type III radio bursts and extreme ultraviolet (EUV) observations from multiple spacecraft in order to identify the solar origin of the electron events. Electron anisotropies and timing as well as the plasma and magnetic field environment were evaluated to characterize the interplanetary transport conditions. Results. All electron events were clearly associated with type III radio bursts. EUV jets were also found in association with all of them except one. A diversity of time profiles and pitch-angle distributions was observed. Different source locations and different magnetic connectivity and transport conditions were likely involved. The July 11 event was also detected by Wind, separated 107 degrees in longitude from Solar Orbiter. For the July 22 event, the Suprathermal Electron and Proton sensor of EPD allowed for us to not only resolve multiple electron injections at low energies, but it also provided an exceptionally high pitch-angle resolution of a very anisotropic beam. This, together with radio observations of local Langmuir waves suggest a very good magnetic connection during the July 22 event. This scenario is challenged by a high-frequency occultation of the type III radio burst and a nominally non-direct connection to the source; therefore, magnetic connectivity requires further investigation.</p