Bi-Level Model for Design of Transit Short-Turning Service Considering Bus Crowding

2017 ◽  
Vol 2649 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Xiyu Yang ◽  
Yuxiong Ji ◽  
Yuchuan Du ◽  
H. Michael Zhang
Keyword(s):  
Optimal Design ◽  
Logit Model ◽  
Operational Cost ◽  
Time Cost ◽  
Total Cost ◽  
Proposed Model ◽  
Level Model ◽  
Upper Level ◽  
Vehicle Travel Time

A bi-level model was developed to design the short-turning strategy on a bus route. The upper-level model aimed at minimizing the total cost, including operational cost, passengers’ waiting time cost, and in-vehicle travel time cost. The lower-level model was a logit model to capture the service choices of passengers. The effects of bus crowding and seat availability were considered explicitly in the proposed model. An algorithm was developed to determine the frequencies of different services and the turnback points of the short-turning service. A case study demonstrates the superiority of the proposed model over alternative models. Sensitivity of the optimal design to seat capacity was also investigated.

Bi-level Game Model for Interaction between Arctic and Traditional Routes

2018 ◽  
Vol 72 (2) ◽  
pp. 269-289 ◽  
Author(s):  
Yangjun Wang ◽  
Ren Zhang
Keyword(s):  
Nash Equilibrium Problem ◽  
Reduced Gradient Method ◽  
Proposed Model ◽  
Arctic Shipping ◽  
Reduced Gradient ◽  
Level Model ◽  
Upper Level ◽  
Path Assignment ◽  
Speed Adjustment

This paper proposes a bi-level model from the perspective of game theory to describe the effect of the rise of Arctic shipping routes on traditional routes and their response. The upper-level model demonstrates the competition between shipping companies that maximise their own profits via speed adjustment, which can be presented as a generalised Nash equilibrium problem and is solved by the generalised reduced-gradient method. The lower-level model illustrates the response of customers who reassign their demands with an elastic total demand, which is presented as a logit-type multi-path assignment problem and is solved by the iterative balancing method. A case study is used to examine the rationality of the proposed model and algorithm.

scholarly journals A Bi-Level Programming Model for Optimal Bus Stop Spacing of a Bus Rapid Transit System

Mathematics ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 625
Author(s):  
Cheng ◽  
Zhao ◽  
Zhang
Keyword(s):  
Programming Model ◽  
Bus Rapid Transit ◽  
Rapid Transit ◽  
Transit System ◽  
Bus Stop ◽  
Proposed Model ◽  
Level Model ◽  
Bus Stop Spacing ◽  
Stop Spacing

The purpose of this study is to create a bi-level programming model for the optimal bus stop spacing of a bus rapid transit (BRT) system, to ensure simultaneous coordination and consider the interests of bus companies and passengers. The top-level model attempts to optimize and determine optimal bus stop spacing to minimize the equivalent costs, including wait, in-vehicle, walk, and operator costs, while the bottom-level model reveals the relation between the locations of stops and spatial service coverage to attract an increasing number of passengers. A case study of Chengdu, by making use of a genetic algorithm, is presented to highlight the validity and practicability of the proposed model and analyze the sensitivity of the coverage coefficient, headway, and speed with different spacing between bus stops.

Optimal Design for Compact Heat Exchanger (Che) by Heat Transfer Viewpoint as an Air Pre-Heater

2015 ◽  
Vol 31 (5) ◽  
pp. 583-590 ◽  
Author(s):  
H. Ghadamian ◽  
H. A. Ozgoli ◽  
F. Esmailie
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Optimal Design ◽  
Compact Heat Exchanger ◽  
Optimal Point ◽  
Operation Conditions ◽  
Proposed Model ◽  
Heat Transfer Capacity ◽  
Programming Analysis

AbstractIn the provided research, the design of CHE (Compact Heat Exchanger) is evaluated and discussed from the heat transfer aspect. Benefiting from present equations and considering the objective concepts, the procedural chart is proposed for achieving optimal design. The main goal of this research study is implementing a new algorithm for optimization to modify a conventional design of CHE. Nonlinear gradient mathematical modeling with different scenarios on free or related variables is developed to cover the purpose of maximizing total heat transfer capacity. By mathematical programming analysis, a model has been provided for optimal design and developed in the GAMS (Generalized Algebraic Modelling System) software. Also for further model test rig development purpose, the proposed model has been incorporated in Matlab software using independent variants and the accuracy of the responses was again evaluated. The comparison indicated 109W/K difference in the exchanged thermal energy rate compared to the optimal exchanger operation conditions. After introducing case study to this model, an acceptable response with 0.997W/K difference on optimal point was achieved. Solving the model indicated 0.833W/K difference with the optimal point, which confirms the resulted technical responses.

A mathematical formulation of time-cost and reliability optimization for supply chain management in research-development projects

2019 ◽  
Vol 53 (4) ◽  
pp. 1385-1406
Author(s):  
M. Forozandeh ◽  
E. Teimoury ◽  
A. Makui
Keyword(s):  
Supply Chain ◽  
Supply Chain Management ◽  
Development Projects ◽  
Management Problem ◽  
Research Development ◽  
Time Cost ◽  
Chain Management ◽  
Proposed Model ◽  
Goal Programming Model

One of the most important strategic decisions in Research-Development projects is network design. It needs to be optimized for the long-term efficient operation. This paper aims at designing the network of Supply Chain for R&D projects. Accordingly, it proposes a Goal programming model for solving a Project-oriented Supply Chain Management problem. The proposed model is developed to determine the optimal combination of the main contractors, executers, and various alternatives for project implementation. The model optimizes time, cost and reliability in the whole lifecycle for the R&D projects. A case study is presented to validate and illustrate the proposed model. The main reason for the high cost and time in the case study was due to the incorrect choice of the network of suppliers and consultants. The model has been tested by the numerical data, revealing that the model could have a significant contribution to the productivity of project-oriented organization. This model could serve as a guideline for managers and decision makers in R&D projects, enabling them to identify the best networks of the SC in their organizations to resolve and improve problems. It also acts as a useful basis for researchers to continue research concerning SCM in R&D projects.

scholarly journals ALOKASI KEBUTUHAN ALAT BERAT PADA PEKERJAAN NORMALISASI MUARA SUNGAI SIBELIS KOTA TEGAL

2019 ◽  
Vol 12 (1) ◽  
pp. 44
Author(s):  
Fandi Azhim ◽  
Suhariyanto , ◽  
Burhamtoro ,
Keyword(s):  
River Estuary ◽  
Operational Cost ◽  
Time Cost ◽  
Sheet Pile ◽  
Microsoft Excel ◽  
Cross Sectional ◽  
Total Cost ◽  
Heavy Equipment ◽  
Crawler Crane

The estuary of River Sibelis is vessel traffic modes of fishermen and the risk rob flooding. The estuary of River Sibelis (STA 0+00 – STA 0+373) project employed some heavy equipment to undertake the project. The purpose of  find out the needs of heavy equipment, productivity of heavy equipment, the duration of work and heavy equipment operational cost. The required data were of layouts, cross sectional drawings of the river estuary, and specifications of heavy equipment. Microsoft Excel program was applied for the calculation and the schedule using method Barchart.The implementation results are as follow: 1) exavating sediment on 29 work days using 1 unit of crane barge in productivity of 80.8 m3/h at Rp. 1.120.384.700,- ; 2) excavating sediment on 16 work days using 2 units of backhoe, 2 units of barge, and 1 unit of tug boat in productivity of 48 m3/h at Rp.351.309,- ; 3) setting sheet pile on 33 work days using 2 units of crawler crane, 1 unit of diesel hammer, 1 unit of tug boat, and 2 units of barge in productivity of 11 m/h at Rp. 805.385.500,-; at total cost project of  Rp. 2.846.349.000,- on  63 work days. Keywords: heavy equipment, productivity, time, cost

scholarly journals Two-Level Planning of Customized Bus Routes Based on Uncertainty Theory

2021 ◽  
Vol 13 (20) ◽  
pp. 11418
Author(s):  
Bing Zhang ◽  
Zhishan Zhong ◽  
Zi Sang ◽  
Mingyang Zhang ◽  
Yunqiang Xue
Keyword(s):  
Uncertainty Theory ◽  
Optimization Problem ◽  
Operating Time ◽  
Route Planning ◽  
Theoretical Support ◽  
Level Model ◽  
Upper Level ◽  
Bus Route Planning ◽  
Two Level Model

The optimization problem of customized bus routes is affected by uncertain factors in reality; therefore, this paper introduces uncertainty theory to study the above problem. A two-level planning model that takes the maximum total revenue of the bus company as the upper-level goal and the minimum total travel cost of passengers as the lower-level goal is established, using uncertainty theory to study and solve practical problems with uncertain factors. The genetic algorithm is used to solve the model, and the feasibility of the model is verified through a case study. The research results show that the application of the two-level model of customized bus route planning based on uncertain vehicle operating time established in this paper to customize bus route planning can take into account the travel needs of passengers and high-quality experiences while also bringing benefits to enterprises and achieving a win–win situation. The research in this article provides theoretical support for the optimization of customized bus routes.

Network Design of Park-and-Ride System to Promote Transit Patronage

2014 ◽  
Vol 1030-1032 ◽  
pp. 2050-2053 ◽  
Author(s):  
Xin Yuan Chen ◽  
Zhi Yuan Liu ◽  
Wei Deng
Keyword(s):  
Logit Model ◽  
Programming Model ◽  
Search Algorithm ◽  
Multinomial Logit Model ◽  
Tabu Search Algorithm ◽  
Park And Ride ◽  
Assignment Model ◽  
Mode Split ◽  
Level Model ◽  
Upper Level

This paper proposed a bi-level programming model to optimize the locations and capacity for rail-based park-and-ride sites to promote transit patronage. A multinomial logit model was incorporated in a mode split/traffic assignment model to assess any given park-and-ride scheme. This model was then taken as the lower level model, and the upper level programming model is established to optimize the location and capacity of park-and-ride with the goal of promoting transit patronage. A heuristic tabu search algorithm is then adopted to solve this model.

Optimal Design of Two-Sided Market Platforms: An Empirical Case Study of Ebay

2013 ◽  
Author(s):  
Aaron Bodoh-Creed ◽  
JJrn Boehnke ◽  
Brent Richard Hickman
Keyword(s):  
Optimal Design

scholarly journals Modeling of Emergency Supply Scheduling Problem Based on Reliability and Its Solution Algorithm under Variable Road Network after Sudden-Onset Disasters

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Tinggui Chen ◽  
Shiwen Wu ◽  
Jianjun Yang ◽  
Guodong Cong ◽  
Gongfa Li
Keyword(s):  
Road Network ◽  
Road Networks ◽  
Sudden Onset ◽  
The Road ◽  
Bee Colony ◽  
Proposed Model ◽  
Effectiveness And Efficiency ◽  
In Transit ◽  
Emergency Supply

It is common that many roads in disaster areas are damaged and obstructed after sudden-onset disasters. The phenomenon often comes with escalated traffic deterioration that raises the time and cost of emergency supply scheduling. Fortunately, repairing road network will shorten the time of in-transit distribution. In this paper, according to the characteristics of emergency supplies distribution, an emergency supply scheduling model based on multiple warehouses and stricken locations is constructed to deal with the failure of part of road networks in the early postdisaster phase. The detailed process is as follows. When part of the road networks fail, we firstly determine whether to repair the damaged road networks, and then a model of reliable emergency supply scheduling based on bi-level programming is proposed. Subsequently, an improved artificial bee colony algorithm is presented to solve the problem mentioned above. Finally, through a case study, the effectiveness and efficiency of the proposed model and algorithm are verified.

scholarly journals Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 801
Author(s):  
Gianluca Valenti ◽  
Aldo Bischi ◽  
Stefano Campanari ◽  
Paolo Silva ◽  
Antonino Ravidà ◽  
...  
Keyword(s):  
Numerical Study ◽  
Thermal Storage ◽  
Primary Energy ◽  
Operational Cost ◽  
Cogeneration Plant ◽  
Economic Optimization ◽  
Viable Option ◽  
Heating Value ◽  
Energy Flows

Stirling units are a viable option for micro-cogeneration applications, but they operate often with multiple daily startups and shutdowns due to the variability of load profiles. This work focused on the experimental and numerical study of a small-size commercial Stirling unit when subjected to cycling operations. First, experimental data about energy flows and emissions were collected during on–off operations. Second, these data were utilized to tune an in-house code for the economic optimization of cogeneration plant scheduling. Lastly, the tuned code was applied to a case study of a residential flat in Northern Italy during a typical winter day to investigate the optimal scheduling of the Stirling unit equipped with a thermal storage tank of diverse sizes. Experimentally, the Stirling unit showed an integrated electric efficiency of 8.9% (8.0%) and thermal efficiency of 91.0% (82.2%), referred to as the fuel lower and, between parenthesis, higher heating value during the on–off cycling test, while emissions showed peaks in NOx and CO up to 100 ppm but shorter than a minute. Numerically, predictions indicated that considering the on–off effects, the optimized operating strategy led to a great reduction of daily startups, with a number lower than 10 per day due to an optimal thermal storage size of 4 kWh. Ultimately, the primary energy saving was 12% and the daily operational cost was 2.9 €/day.

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