Continuous Approximation Model for Hybrid Flexible Transit Systems with Low Demand Density

2021 ◽  
pp. 036119812199713
Author(s):  
Charalampos Sipetas ◽  
Eric J. Gonzales
Keyword(s):  
Agency Cost ◽  
Optimization Techniques ◽  
Optimization Process ◽  
Analytical Models ◽  
Continuous Approximation ◽  
Flexible Systems ◽  
Transit System ◽  
Transit Systems ◽  
Approximation Techniques ◽  
Service Areas

Flexible transit systems are a way to address challenges associated with conventional fixed route and fully demand responsive systems. Existing studies indicate that such systems are often planned and designed without established guidelines, and optimization techniques are rarely implemented on actual flexible systems. This study presents a hybrid transit system where the degree of flexibility can vary from a fixed route service (with no flexibility) to a fully flexible transit system. Such a system is expected to be beneficial in areas where the best transit solution lies between the fixed route and fully flexible systems. Continuous approximation techniques are implemented to model and optimize the stop spacing on a fixed route corridor, as well as the boundaries of the flexible region in a corridor. Both user and agency costs are considered in the optimization process. A numerical analysis compares various service areas and demand densities using input variables with magnitudes similar to those of real-world case studies. Sensitivity analysis is performed for service headway, percent of demand served curb-to-curb, and user and agency cost weights in the optimization process. The analytical models are evaluated through simulations. The hybrid system proposed here achieves estimated user benefits of up to 35% when compared with fixed route systems, under different case scenarios. Flexible systems are particularly beneficial for serving corridors with low or uncertain demand. This provides value for corridors with low demand density as well as communities in which transit ridership has dropped significantly because of the COVID-19 pandemic.

RiRiShun Logistics: Home Appliance Delivery Data for the 2021 Manufacturing & Service Operations Management Data-Driven Research Challenge

2021 ◽  
Author(s):  
Xiaolong Guo ◽  
Yugang Yu ◽  
Gad Allon ◽  
Meiyan Wang ◽  
Zhentai Zhang
Keyword(s):  
Operations Management ◽  
Service Operations ◽  
Optimization Techniques ◽  
Data Driven ◽  
Analytical Models ◽  
Data Set ◽  
Service Operations Management ◽  
Level Data ◽  
Home Appliance ◽  
Research Challenge

To support the 2021 Manufacturing & Service Operations Management (MSOM) Data-Driven Research Challenge, RiRiShun Logistics (a Haier group subsidiary focusing on logistics service for home appliances) provides MSOM members with logistics operational-level data for data-driven research. This paper provides a detailed description of the data associated with over 14 million orders from 149 clients (the consigners) associated with 4.2 million end consumers (the recipients and end users of the appliances) in China, involving 18,000 stock keeping units operated at 103 warehouses. Researchers are welcomed to develop econometric models, data-driven optimization techniques, analytical models, and algorithm designs by using this data set to address questions suggested by company managers.

Accessibility Scenario Analysis of a Hypothetical Future Transit Network: Social Equity Implications of a General Transit Feed Specification–Based Sketch Planning Tool

2017 ◽  
Vol 2671 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Andrew Guthrie ◽  
Yingling Fan ◽  
Kirti Vardhan Das
Keyword(s):  
Planning Process ◽  
Social Equity ◽  
Social Benefit ◽  
Planning Tool ◽  
Transit Planning ◽  
Transit System ◽  
Transit Systems ◽  
Transit Network ◽  
Accessibility Analysis ◽  
Transit Accessibility

Accessibility analysis can have important implications for understanding social equity in transit planning. The emergence and the increasingly broad acceptance of the general transit feed specification (GTFS) format for transit route, stop, and schedule data have revolutionized transit accessibility research by providing researchers with a convenient, publicly available source of data interoperable with common geographic information system (GIS) software. Existing approaches to GTFS-based transit analysis, however, focus on currently operating transit systems. With major transit expansions across the nation and around the world increasing in number and ambition, understanding the accessibility impacts of proposed projects in their early planning stages is crucial to achieving the greatest possible social benefit from these massive public investments. This paper describes the development of a hypothetical transit network based on current GTFS data and proposed 2040 transit improvements for the Twin Cities region of Minneapolis–Saint Paul, Minnesota, as well as its use as a sketch planning tool in exploring the proposed system’s impacts on access to job vacancies from historically disadvantaged areas. This research demonstrates the importance of accessibility analysis in planning a transit system that increases opportunity for marginalized workers and concludes by calling for broader, easier access to accessibility analysis for practitioners and community groups to refine the early stages of the transit planning process and democratize an increasingly crucial transit planning tool.

scholarly journals Combining Analytical Models and Mesh Morphing Based Optimization Techniques for the Design of Flying Multihulls Appendages

2021 ◽  
Vol 6 (01) ◽  
pp. 151-172
Author(s):  
Ubaldo Cella ◽  
Corrado Groth ◽  
Stefano Porziani ◽  
Alberto Clarich ◽  
Francesco Franchini ◽  
...  
Keyword(s):  
Numerical Optimization ◽  
Fluid Dynamic ◽  
Optimization Procedure ◽  
Optimization Techniques ◽  
Analytical Models ◽  
High Fidelity ◽  
Mesh Morphing ◽  
Wide Range ◽  
Global Equilibrium ◽  
Range Of Values

Abstract The fluid dynamic design of hydrofoils involves most of the typical difficulties of aeronautical wings design with additional complexities related to the design of a device operating in a multiphase environment. For this reason, “high fidelity” analysis solvers should be, in general, adopted also in the preliminary design phase. In the case of modern fast foiling sailing yachts, the appendages accomplish both the task of lifting up the boat and to make possible upwind sailing by contributing balance to the sail side force and the heeling moment. Furthermore, their operative design conditions derive from the global equilibrium of forces and moments acting on the system which might vary in a very wide range of values. The result is a design problem defined by a large number of variables operating in a wide design space. In this scenario, the device performing in all conditions has to be identified as a trade-off among several conflicting requirements. One of the most efficient approaches to such a design challenge is to combine multi-objective optimization strategies with experienced aerodynamic design. This paper presents a numerical optimization procedure suitable for foiling multihulls. As a proof of concept, it reports, as an application, the foils design of an A-Class catamaran. The key point of the method is the combination of opportunely developed analytical models of the hull forces with high fidelity multiphase analyses in both upwind and downwind sailing conditions. The analytical formulations were tuned against a database of multiphase analyses of a reference demihull at several attitudes and displacements. An aspect that significantly contributes to both efficiency and robustness of the method is the approach adopted to the geometric parametrization of the foils which was implemented by a mesh morphing technique based on Radial Basis Functions.

Finite Element Analysis of Rail-End Bolt Hole and Fillet Stress on Bolted Rail Joints

2017 ◽  
Vol 2607 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Kaijun Zhu ◽  
Yu Qian ◽  
J. Riley Edwards ◽  
Bassem O. Andrawes
Keyword(s):  
Finite Element ◽  
Vertical Displacement ◽  
Rail Transit ◽  
Rail Transportation ◽  
Element Analysis ◽  
Transit System ◽  
Transit Systems ◽  
Service Failures ◽  
The University ◽  
Continuously Welded Rail

A rail joint typically is one of the weakest elements of a track superstructure, primarily because of discontinuities in its geometric and mechanical properties and the high-impact loads induced by these discontinuities. The development of continuously welded rail has significantly reduced the number of rail joints, but many bolted joints remain installed in rail transit systems. Because of the unique loading environment of a rail transit system (especially high-frequency, high-repetition loads), defects related to bolted rail joints (e.g., joint bar failures, bolt hole cracks, and cracks in the upper fillet) continue to cause service failures and can pose derailment risks. Recent research in the Rail Transportation and Engineering Center at the University of Illinois at Urbana–Champaign has focused on investigating crack initiation in the bolt hole and fillet areas of bolted rail joints. Stress distribution was investigated at the rail-end bolt hole and upper fillet areas of standard, longer, and thicker joint bars under static loading conditions. Numerical simulations were organized into a comprehensive parametric analysis performed with finite element modeling. Preliminary results indicated that the longer joint bar performed similarly to the standard joint bar but the thicker joint bar reduced rail vertical displacement and rail upper fillet stresses compared with the standard joint bar. However, the thicker joint bar also may generate higher stresses at the rail-end bolt hole. Additionally, joint bar performance was dependent on the rail profile and bolt hole location.

Planning Transit System for Indian Cities

2018 ◽  
pp. 1647-1672
Author(s):  
Arnab Jana ◽  
Ronita Bardhan
Keyword(s):  
Land Use ◽  
Traffic Congestion ◽  
Transit System ◽  
Transit Systems ◽  
Seamless Connectivity ◽  
Global Environmental ◽  
Limited Opportunity ◽  
Land Use Development ◽  
Parking Demand ◽  
Indian Cities

Indian cities are currently in a phase of transition. Continuous urbanization and seamless connectivity is the paradigm. Proliferating bourgeois class is extending the demand for private automobiles. With limited opportunity to increment land use allocated to transportation and rapid shift towards automobile ownership, importance of transit system is being sensed. City managers believe that public transit could be an alternative in providing solution to ever increasing problem of traffic congestion, parking demand, accidents and fatalities, and global environmental adversities. This chapter examines the critical planning issues that need to be addressed. It highlights the opportunities and challenges these cities are poised towards transit system planning. The experiences from cities worldwide that have adopted transit systems to create compact city forms fostering mixed land use development are exemplified here. A ‘3P' developmental framework of ‘provide', ‘promote' and ‘progress' has been proposed to harness the opportunity.

Client Referral, Ridership, and Financial Tracking [CRRAFT] Transit Management System: CRRAFTing a Bridge to Coordinated Interagency Transportation

2003 ◽  
Vol 1841 (1) ◽  
pp. 62-72 ◽  
Author(s):  
Judith M. Espinosa ◽  
Matthew R. Baca ◽  
Amy D. Estelle ◽  
Nancy Bennett ◽  
Geri Knoebel ◽  
...  
Keyword(s):  
New Mexico ◽  
Service Delivery ◽  
Human Service ◽  
Management System ◽  
Support Service ◽  
Service Agency ◽  
Transit System ◽  
Transit Systems ◽  
Client Referral ◽  
Transportation Research

From the 1990s on, a growing number of federal and state human service programs have identified transportation as an allowable, often vital, support service for clients. State human services agencies in New Mexico are improving clients’ transportation options either by funding the expansion of local transit operators’ service areas and hours, or the starting up of new transit systems. Agencies providing this new transportation funding require specific reports based on the human service delivery model. Because services are client-based, the reports include the number of unique clients served, number of trips provided to each client, trip purposes, and costs. For New Mexico rural transit systems that operate under FTA Section 5311 guidelines, services and reports are trip based. To bridge the gap between human service agency and rural transit system cultures, the Alliance for Transportation Research Institute of the University of New Mexico developed a web-based software program, the Client Referral, Ridership, and Financial Tracking (CRRAFT) Transit Management System. The software integrates human service client transportation referral and service delivery with daily rural public transit operations, provides passengers with increased seamlessness in transportation service, and generates financial and client tracking reports that meet each funding agency’s criteria, including those required by FTA. The CRRAFT lessens the burden on small transit systems that have limited administrative staff of two to three people. The software also provides funding agencies with tools to facilitate planning and to maintain administrative and fiscal accountability.

scholarly journals Optimization Model for Reserve Fleet Sizes in Traditional Transit Systems considering the Risk of Vehicle Breakdowns

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bowen Hou ◽  
Shuzhi Zhao ◽  
Huasheng Liu ◽  
Jin Li
Keyword(s):  
Optimization Model ◽  
Queueing Theory ◽  
Solution Method ◽  
Transit System ◽  
Transit Systems ◽  
Total Cost ◽  
User Costs ◽  
Transit Services ◽  
Optimized Model ◽  
In Transit

Traditional transit systems are susceptible to unexpected costs and delays due to unforeseen events, such as vehicle breakdowns. The randomness of these events gives the appearance of an imbalance in the number of operating vehicles and of unreliable transit services. Therefore, this paper proposes the queueing theory as a means to characterize the state of any given transit system considering the risk of vehicle breakdowns. In addition, the proposed method is used to create an optimized model for reserve fleet sizes in transit systems, in order to ensure the reliability of the transit system and minimize the total cost of any transit system exposed to the risks of vehicle breakdowns. The optimization is conducted based on the two main characteristics of all bus systems, namely, operator costs and user costs, in both normal and disruptive situations. In addition, the situations in our optimization are generated in scenarios that have a certain degree of probability of experiencing delays. This paper formulates such an optimization model, presents the formulation solution method, and proves the validity of the proposed method.

Assessing the Existing Bursa Light Rail Transportation System

2020 ◽  
Vol 2674 (10) ◽  
pp. 250-260
Author(s):  
Mehmet Rizelioğlu ◽  
Turan Arslan
Keyword(s):  
Traffic Congestion ◽  
Transportation System ◽  
Transportation Systems ◽  
Bus Rapid Transit ◽  
Light Rail ◽  
Rail Transportation ◽  
Transit System ◽  
Transit Systems ◽  
Negative Impacts

As car ownership soars, traffic congestion and its associated negative impacts have become real concerns in many cities around the world. Therefore, transportation systems that perform better in eliminating or reducing traffic congestion and related problems to tolerable levels have become imperative. Alternative transit systems should be assessed properly to accommodate the expected demand in the long term, at least, to some significant extent. However, this is generally neglected in developing countries and, among many possible alternatives, a popular transportation system is usually preferred within the available budget. As an example, Bursa Metropolitan Municipality, Turkey, has recently implemented a light rail transportation system (LRT) on its major east–west corridor as the main transit system. In this study, the existing LRT is assessed and its performance is compared with a hypothetical bus rapid transit (BRT) system, which is a strong contender and comparatively a lower-cost alternative. This is done to assess whether the LRT was the better choice in relation to the current demand. Therefore, in this study, the existing LRT system is first defined in the PTV VISSIM simulation environment. Then, the hypothetical BRT system is considered on the same route with the current demand. The capability and capacities of the existing LRT and the BRT system are assessed and compared in many aspects. The results are compared, and important findings are outlined.

scholarly journals Flywheel vs. Supercapacitor as Wayside Energy Storage for Electric Rail Transit Systems

Inventions ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 62
Author(s):  
Mahdiyeh Khodaparastan ◽  
Ahmed Mohamed
Keyword(s):  
Energy Storage ◽  
Energy Saving ◽  
Voltage Regulation ◽  
Appropriate Technology ◽  
Rail Transit ◽  
Peak Demand ◽  
Transit System ◽  
Transit Systems ◽  
Industrial Sectors ◽  
Demand Reduction

Energy storage technologies are developing rapidly, and their application in different industrial sectors is increasing considerably. Electric rail transit systems use energy storage for different applications, including peak demand reduction, voltage regulation, and energy saving through recuperating regenerative braking energy. In this paper, a comprehensive review of supercapacitors and flywheels is presented. Both are compared based on their general characteristics and performances, with a focus on their roles in electric transit systems when used for energy saving, peak demand reduction, and voltage regulation. A cost analysis is also included to provide initial guidelines on the selection of the appropriate technology for a given transit system.

An Analysis of Success Plans and Performance Measures for Rural Transit Systems in North Carolina

2019 ◽  
Vol 2673 (3) ◽  
pp. 97-105 ◽  
Author(s):  
Kai Monast ◽  
Charlie Stanfield
Keyword(s):  
North Carolina ◽  
Customer Service ◽  
Internal Consistency ◽  
Public Transportation ◽  
Performance Metrics ◽  
Mission Statement ◽  
Transit System ◽  
Transit Systems ◽  
North Carolina Department ◽  
The North

Performance measurement and funding allocation based on these measurements are becoming increasingly popular in public transportation. Understanding what is important to transit systems is critical to properly assess them on their operational and administrative performance. The research goals were to determine how rural transit systems in North Carolina define success, what performance metrics the systems select for themselves, and why they selected those metrics. Each transit system was required by the North Carolina Department of Transportation to create a Success Plan for themselves that consisted of a mission statement, vision statement, values, and a scorecard that contained performance metrics. The analysis of these Success Plans shows that rural transit systems broadly define their values based on customer service, safety, and reliability. However, aside from safety, the specific metrics that the systems use for evaluating their performance are not well connected to these values. This lack of internal consistency within the Success Plans means that rural transit systems are not selecting performance metrics that complement their stated goals. This lack of internal consistency could have many causes and interviews were conducted with public transit administrators in North Carolina to try and understand the causes. From these interviews, it was determined that the lack of internal consistency in the plans could be partially attributed to the following: (1) system administrators were not aware of the importance of internally consistent plans; (2) system administrators had difficulty creating metrics; and (3) system administrators included metrics that they felt the state wanted to see.

Sign in / Sign up

Export Citation Format

Share Document