scholarly journals Global Optimization for Transport Network Expansion and Signal Setting

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Haoxiang Liu ◽  
David Z. W. Wang ◽  
Hao Yue
Keyword(s):  
Global Optimization ◽  
Network Design ◽  
Network Performance ◽  
Network Capacity ◽  
Capacity Allocation ◽  
Urban Transport ◽  
Transport Network ◽  
Mixed Integer ◽  
Planning Problem ◽  
Transport Planning

This paper proposes a model to address an urban transport planning problem involving combined network design and signal setting in a saturated network. Conventional transport planning models usually deal with the network design problem and signal setting problem separately. However, the fact that network capacity design and capacity allocation determined by network signal setting combine to govern the transport network performance requires the optimal transport planning to consider the two problems simultaneously. In this study, a combined network capacity expansion and signal setting model with consideration of vehicle queuing on approaching legs of intersection is developed to consider their mutual interactions so that best transport network performance can be guaranteed. We formulate the model as a bilevel program and design an approximated global optimization solution method based on mixed-integer linearization approach to solve the problem, which is inherently nnonlinear and nonconvex. Numerical experiments are conducted to demonstrate the model application and the efficiency of solution algorithm.

Evaluation of the Traffic Impacts of Mass Evacuation of Halifax: Flood Risk and Dynamic Traffic Microsimulation Modeling

2018 ◽  
Vol 2672 (1) ◽  
pp. 148-160 ◽  
Author(s):  
MD Jahedul Alam ◽  
Muhammad Ahsanul Habib ◽  
Kevin Quigley ◽  
Tim L. Webster
Keyword(s):  
Flood Risk ◽  
Network Performance ◽  
Comprehensive Evaluation ◽  
Dynamic Traffic Assignment ◽  
Network Capacity ◽  
Transport Network ◽  
Dynamic Traffic ◽  
Traffic Impacts ◽  
Microsimulation Modeling ◽  
Mass Evacuation

This paper presents a comprehensive evaluation of traffic impacts of a mass evacuation of the Halifax Peninsula under several flooding scenarios. Flood extent and associated damages to the transport network are identified through digital elevation modeling that intersects with the Halifax stream and transport networks. The resulting flood scenarios inform a traffic microsimulation model that uses a dynamic traffic assignment-based microsimulation approach and simulates the evacuation of 34,808 evacuees estimated from the Halifax Regional Transport Network Model. The simulation results suggest that flooding of the links by 7.9 m flood reduces alternative evacuation routes by 31.2%. It takes 15 hours to evacuate 83% of evacuees while the remaining 17% are not accommodated in the network due to reduced network capacity. The number of vehicles in the network has peaked at 13,000 in this flooding scenario. An evaluation of network performance reveals a sustained congestion prevailing from 4th to 7th hour of the evacuation. The novelty of this study is that it develops a comprehensive tool of flood risk and dynamic traffic microsimulation modeling to offer an in-depth evaluation of potential impacts during evacuation. The results will help emergency professionals in evacuation planning and making emergency decisions.

scholarly journals Simulation analysis of the western 3rd ring road project in Krakow and its forecast impact upon the urban transport network performance

2018 ◽  
Vol 2018 (8) ◽  
pp. 12-24
Author(s):  
Arkadiusz Drabicki ◽  
Andrzej Szarata ◽  
Rafał Kucharski
Keyword(s):  
Inner City ◽  
Transport System ◽  
Road Network ◽  
Network Performance ◽  
Simulation Analysis ◽  
Urban Transport ◽  
Transport Network ◽  
Ring Road ◽  
Road Project ◽  
The City

The paper presents results from simulation analysis of the western 3rd ring road project in the city of Krakow (i.e. Trasa Lagiewnicka, Trasa Pychowicka and Trasa Zwierzyniecka), performed in the macroscopic model of transport system in the Krakow metropolitan area. Simulation works reveal shifts in traffic flows and changes in urban transport network performance which would likely take place after the stage-wise construction of consecutive 3rd ring road western sections. Results indicate that the analysed road schemes would indeed have a relevant impact upon travel conditions, though in initial stages these would be rather limited and confined to the southern part of the city. Therefore, completion of the whole western section of the 3rd ring road is crucial to its overall effectiveness and would only then bring substantial benefits on a city-wide scale. Simulation works seem to confirm that the future 3rd ring road would become an essential and highly-utilised link in the urban road network and would provide a much more efficient connection between the northern and southern parts of the Krakow city. However, apart from the projected benefits, it is also important to underline potential negative implications – and consequently, further changes in city transport system should envisage reduction of the road network capacity within the inner-city area. This would then provide the best possible chance of fostering the improvements achieved with the 3rd ring road scheme: i.e., positive changes in accessibility and travelling conditions across the whole city and long-term, sustainable traffic congestion relief in the inner-city Krakow area.

Urban Transport Network Capacity Considering Level of Service

ICCTP 2009 ◽  
2009 ◽  
Author(s):  
Huapu Lu ◽  
Xinxin Yu ◽  
Haiwei Wang ◽  
Changzhi Bian ◽  
Ziyin Deng
Keyword(s):  
Network Capacity ◽  
Urban Transport ◽  
Transport Network ◽  
Level Of Service

scholarly journals Campus realities: Forecasting user bandwidth utilization using monte carlo simulation

2020 ◽  
Vol 10 (5) ◽  
pp. 4809
Author(s):  
Haruna Bege ◽  
Aminu Yusuf Zubairu
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Network Design ◽  
Network Performance ◽  
Network Capacity ◽  
Traffic Load ◽  
Smart Devices ◽  
Campus Network ◽  
Bandwidth Utilization ◽  
Available Bandwidth

Adequate network design, planning, and improvement are pertinent in a campus network as the use of smart devices is escalating. Underinvesting and overinvesting in campus network devices lead to low network performance and low resource utilization respectively. Due to this fact, it becomes very necessary to ascertain if the current network capacity satisfies the available bandwidth requirement. The bandwidth demand varies from different times and periods as the number of connected devices is on the increase. Thus, emphasizing the need for adequate bandwidth forecast. This paper presents a Monte Carlo simulation model that forecast user bandwidth utilization in a campus network. This helps in planning campus network design and upgrade to deliver available content in a period of high and normal traffic load.

Performance Modeling and Analysis of WDM Optical Networks under Wavelength Continuity Constraint using MILP

2020 ◽  
Vol 13 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Swati Bhalaik ◽  
Ashutosh Sharma ◽  
Rajiv Kumar ◽  
Neeru Sharma
Keyword(s):  
Network Design ◽  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Optical Network ◽  
Optimal Path ◽  
Topology Design ◽  
Mixed Integer ◽  
Wdm Optical Networks ◽  
Virtual Topology ◽  
Wdm Network

Objective: Optical networks exploit the Wavelength Division Multiplexing (WDM) to meet the ever-growing bandwidth demands of upcoming communication applications. This is achieved by dividing the enormous transmission bandwidth of fiber into smaller communication channels. The major problem with WDM network design is to find an optimal path between two end users and allocate an available wavelength to the chosen path for the successful data transmission. Methods: This communication over a WDM network is carried out through lightpaths. The merging of all these lightpaths in an optical network generates a virtual topology which is suitable for the optimal network design to meet the increasing traffic demands. But, this virtual topology design is an NP-hard problem. This paper aims to explore Mixed Integer Linear Programming (MILP) framework to solve this design issue. Results: The comparative results of the proposed and existing mathematical models show that the proposed algorithm outperforms with the various performance parameters. Conclusion: Finally, it is concluded that network congestion is reduced marginally in the overall performance of the network.

scholarly journals A Multi-Echelon Network Design in a Dual-Channel Reverse Supply Chain Considering Consumer Preference

2021 ◽  
Vol 18 (9) ◽  
pp. 4760
Author(s):  
Peng Li ◽  
Di Wu
Keyword(s):  
Supply Chain ◽  
Network Design ◽  
Environmental Sustainability ◽  
Rapid Development ◽  
Consumer Preference ◽  
Service Level ◽  
Mixed Integer ◽  
Reverse Supply Chain ◽  
Related Factors ◽  
Dual Channel

The rapid development of e-commerce technologies has encouraged collection centers to adopt online recycling channels in addition to their existing traditional (offline) recycling channels, such the idea of coexisting traditional and online recycling channels evolved a new concept of a dual-channel reverse supply chain (DRSC). The adoption of DRSC will make the system lose stability and fall into the trap of complexity. Further the consumer-related factors, such as consumer preference, service level, have also severely affected the system efficiency of DRSC. Therefore, it is necessary to help DRSCs to design their networks for maintaining competitiveness and profitability. This paper focuses on the issues of quantitative modelling for the network design of a general multi-echelon, dual-objective DRSC system. By incorporating consumer preference for the online recycling channel into the system, we investigate a mixed integer linear programming (MILP) model to design the DRSC network with uncertainty and the model is solved using the ε-constraint method to derive optimal Pareto solutions. Numerical results show that there exist positive correlations between consumer preference and total collective quantity, online recycling price and the system profits. The proposed model and solution method could assist recyclers in pricing and service decisions to achieve a balance solution for economic and environmental sustainability.

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