scholarly journals Path Optimization Model for Intra-City Express Delivery in Combination with Subway System and Ground Transportation

2019 ◽  
Vol 11 (3) ◽  
pp. 758
Author(s):  
Laijun Zhao ◽  
Xiaoli Wang ◽  
Johan Stoeter ◽  
Yan Sun ◽  
Huiyong Li ◽  
...  
Keyword(s):  
Optimization Model ◽  
Time Window ◽  
Time Windows ◽  
Path Optimization ◽  
Delivery Time ◽  
Basic Scenario ◽  
Study Results ◽  
Subway System ◽  
Express Delivery

Combined conventional ground transport with a subway system for line-haul transport for intra-city express delivery is a new transportation mode. Subway transportation can be used in the line-haul transportation of intra-city express delivery services to reduce cost, improve efficiency, raise customer satisfaction, and alleviate road congestion and air pollution. To achieve this, we developed a path optimization model (POM) with time windows for intra-city express delivery, which makes use of the subway system. Our model integrated the subway system with ground transportation in order to minimize the total delivery time. It considered the time window requirements of the senders and the recipients, and was constrained by the frequency of trains on the subway line. To solve the POM, we designed a genetic algorithm. The model was tested in a case study of a courier company in Shanghai, China. Meanwhile, based on the basic scenario, the corresponding solutions of the four different scenarios of the model are carried out. Then, we further analyzed the influence of the number of vehicles, the frequency of trains on the subway line, and the client delivery time window on the total delivery time, client time window satisfaction, and courier company costs based on the basic scenario. The results demonstrated that the total delivery time and the total time outside the time window decreased as the number of vehicles increased; the total delivery time and the total time outside the time window decreased as the delivery frequency along the subway line increased; the total delivery time and the total time outside the time window decreased as the sender’s time window increased. However, when the sender’s time window increased beyond a certain threshold, the total delivery time and the total time outside the time window no longer decreased greatly. The case study results can guide courier companies in path optimization for intra-city express delivery vehicles in combination with the subway network.

scholarly journals Location Routing Problem with Consideration of CO2 Emissions Cost: A Case Study

2020 ◽  
Vol 21 (2) ◽  
pp. 225-234
Author(s):  
Ananda Noor Sholichah ◽  
Y Yuniaristanto ◽  
I Wayan Suletra
Keyword(s):  
Co2 Emissions ◽  
Time Windows ◽  
Optimal Solution ◽  
Mixed Integer ◽  
Distribution Centers ◽  
Location Routing Problem ◽  
Routing Problem ◽  
Location Routing ◽  
Study Results

Location and routing are the main critical problems investigated in a logistic. Location-Routing Problem (LRP) involves determining the location of facilities and vehicle routes to supply customer's demands. Determination of depots as distribution centers is one of the problems in LRP.  In LRP, carbon emissions need to be considered because these problems cause global warming and climate change. In this paper, a new mathematical model for LRP considering CO2 emissions minimization is proposed. This study developed a new  Mixed Integer Linear Programming (MILP)  model for LRP with time windows and considered the environmental impacts.  Finally, a case study was conducted in the province of Central Java, Indonesia. In this case study, there are three depot candidates. The study results indicated that using this method in existing conditions and constraints provides a more optimal solution than the company's actual route. A sensitivity analysis was also carried out in this case study.

scholarly journals An optimization model for urban transport distribution with time windows: A case study of invoice delivery in a law firm

2021 ◽  
Vol 54 (1) ◽  
pp. 236-242
Author(s):  
L. Reyes-Rubiano ◽  
E.L. Solano-Charris ◽  
Y. Caneva ◽  
M. Müller ◽  
T. Reggelin
Keyword(s):  
Optimization Model ◽  
Time Windows ◽  
Urban Transport ◽  
Law Firm

scholarly journals Exploration of the data space via trans-dimensional sampling: the case study of seismic double difference data

2021 ◽  
Author(s):  
Nicola Piana Agostinetti ◽  
Giulia Sgattoni
Keyword(s):  
Seismic Data ◽  
Time Window ◽  
Time Windows ◽  
Correlation Coefficients ◽  
Double Difference ◽  
Seismicity Rate ◽  
Data Space ◽  
Double Differences ◽  
Time Invariant

Abstract. Double differences (DD) seismic data are widely used to define elasticity distribution in the Earth's interior, and its variation in time. DD data are often pre-processed from earthquakes recordings through expert-opinion, where couples of earthquakes are selected based on some user-defined criteria, and DD data are computed from the selected couples. We develop a novel methodology for preparing DD seismic data based on a trans-dimensional algorithm, without imposing pre-defined criteria on the selection of couples of events. We apply it to a seismic database recorded on the flank of Katla volcano (Iceland), where elasticity variations in time has been indicated. Our approach quantitatively defines the presence of changepoints that separate the seismic events in time-windows. Within each time-window, the DD data are consistent with the hypothesis of time-invariant elasticity in the subsurface, and DD data can be safely used in subsequent analysis. Due to the parsimonious behavior of the trans-dimensional algorithm, only changepoints supported by the data are retrieved. Our results indicate that: (a) retrieved changepoints are consistent with first-order variations in the data (i.e. most striking changes in the DD data are correctly reproduced in the changepoint distribution in time); (b) changepoint locations in time do correlate neither with changes in seismicity rate, nor with changes in waveforms similarity (measured through the cross-correlation coefficients); and (c) noteworthy, the changepoint distribution in time seems to be insensitive to variations in the seismic network geometry during the experiment. Our results proofs that trans-dimensional algorithms can be positively applied to pre-processing of geophysical data before the application of standard routines (i.e. before using them to solve standard geophysical inverse problems) in the so called exploration of the data space.

Crowdsourcing Last-Mile Deliveries

2021 ◽  
Author(s):  
Soraya Fatehi ◽  
Michael R. Wagner
Keyword(s):  
Time Window ◽  
Time Windows ◽  
Problem Definition ◽  
Optimization Approach ◽  
Hourly Wage ◽  
Delivery Time ◽  
On Demand ◽  
Last Mile ◽  
Delivery Services ◽  
On Time Delivery

Problem definition: Because of the emergence and development of e-commerce, customers demand faster and cheaper delivery services. However, many retailers find it challenging to efficiently provide fast and on-time delivery services to their customers. Academic/practical relevance: Amazon and Walmart are among the retailers that are relying on independent crowd drivers to cope with on-demand delivery expectations. Methodology: We propose a novel robust crowdsourcing optimization model to study labor planning and pricing for crowdsourced last-mile delivery systems that are utilized for satisfying on-demand orders with guaranteed delivery time windows. We develop our model by combining crowdsourcing, robust queueing, and robust routing theories. We show the value of the robust optimization approach by analytically studying how to provide fast and guaranteed delivery services utilizing independent crowd drivers under uncertainties in customer demands, crowd availability, service times, and traffic patterns; we also allow for trend and seasonality in these uncertainties. Results: For a given delivery time window and an on-time delivery guarantee level, our model allows us to analytically derive the optimal delivery assignments to available independent crowd drivers and their optimal hourly wage. Our results show that crowdsourcing can help firms decrease their delivery costs significantly while keeping the promise of on-time delivery to their customers. Managerial implications: We provide extensive managerial insights and guidelines for how such a system should be implemented in practice.

Distribution Fairness in Emergency Material Vehicle Scheduling Based on Uncertain Time and Demand

2021 ◽  
Vol 14 (02) ◽  
pp. 2150014
Author(s):  
Jian Li ◽  
Yingying Xiong ◽  
Bao Jiang
Keyword(s):  
Optimization Model ◽  
Vehicle Scheduling ◽  
Delivery Time ◽  
Multi Objective Optimization ◽  
Transport Time ◽  
Multi Objective ◽  
Emergency Rescue ◽  
Scheduling Model ◽  
Uncertain Time

In the emergency rescue of emergencies, the dispatch of emergency materials is one of the most important tasks. The fastest and most equitable distribution of emergency supplies to the affected areas is at the heart of the rescue effort. Considering the transport time between each affected point and the affected people for emergency supplies demand fairness, it is necessary to minimize delivery time. Thus, this paper builds a multi-objective optimization model based on the uncertainty theory to minimize the total cost and maximize the affected rate of demand. Second, this paper establishes a multi-objective optimization model for emergency supplies of vehicle scheduling. Third, the principle of genetic algorithm and the steps of emergency supplies are applied to solve the vehicle scheduling model combined with the case study of the Ya’an earthquake.

Dynamic Opportunistic Maintenance Scheduling for Series Systems Based on Theory of Constraints (TOC)–VLLTW Methodology

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Xinyang Tao ◽  
Tangbin Xia ◽  
Lifeng Xi
Keyword(s):  
Economic System ◽  
Time Window ◽  
Time Windows ◽  
Lag Time ◽  
Maintenance Scheduling ◽  
Theory Of Constraints ◽  
Opportunistic Maintenance ◽  
Maintenance Schedules ◽  
Series Systems

This paper focuses on series systems' dynamic opportunistic maintenance scheduling. Based on the machine-level predictive maintenance (PdM) method, a novel TOC–VLLTW methodology combined theory of constraints (TOC) policy and variable lead-lag time window (VLLTW) policy is proposed. The TOC policy provides machines' priorities according to their PdM durations to decrease system downtime when scheduling opportunistic maintenance. The VLLTW policy provides variable lead-lag time windows against different machines, allowing for more flexible and economic system opportunistic maintenance schedules. This proposed methodology is demonstrated through the case study based on the collected reliability information from a quayside container system. The results can effectively prove the effectiveness of the TOC–VLLTW methodology.

PROCESSING AND IMAGING OF MARINE SEISMIC DATA FROM THE JEQUITINHONHA BASIN (BAHIA, BRAZIL)

2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Lourenildo W.B. Leite ◽  
J. Mann ◽  
Wildney W.S. Vieira
Keyword(s):  
Seismic Data ◽  
Sedimentary Basins ◽  
Study Results ◽  
Marine Seismic ◽  
Present Case Study

ABSTRACT. The present case study results from a consistent processing and imaging of marine seismic data from a set collected over sedimentary basins of the East Brazilian Atlantic. Our general aim is... RESUMO. O presente artigo resulta de um processamento e imageamento consistentes de dados sísmicos marinhos de levantamento realizado em bacias sedimentares do Atlântico do Nordeste...

Sign in / Sign up

Export Citation Format

Share Document