scholarly journals Simulation-Optimization Approach for Multi-Period Facility Location Problems with Forecasted and Random Demands in a Last-Mile Logistics Application

Algorithms ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 41
Author(s):  
Markus Rabe ◽  
Jesus Gonzalez-Feliu ◽  
Jorge Chicaiza-Vaca ◽  
Rafael D. Tordecilla
Keyword(s):  
Facility Location ◽  
Simulation Optimization ◽  
Facility Location Problem ◽  
Decision Support Tool ◽  
Optimal Number ◽  
Dynamics Simulation ◽  
Flow Diagram ◽  
Optimization Approach ◽  
Support Tool ◽  
Last Mile

The introduction of automated parcel locker (APL) systems is one possible approach to improve urban logistics (UL) activities. Based on the city of Dortmund as case study, we propose a simulation-optimization approach integrating a system dynamics simulation model (SDSM) with a multi-period capacitated facility location problem (CFLP). We propose this integrated model as a decision support tool for future APL implementations as a last-mile distribution scheme. First, we built a causal-loop and stock-flow diagram to show main components and interdependencies of the APL systems. Then, we formulated a multi-period CFLP model to determine the optimal number of APLs for each period. Finally, we used a Monte Carlo simulation to estimate the costs and reliability level with random demands. We evaluate three e-shopper rate scenarios with the SDSM, and then analyze ten detailed demand configurations based on the results for the middle-size scenario with our CFLP model. After 36 months, the number of APLs increases from 99 to 165 with the growing demand, and stabilizes in all configurations from month 24. A middle-demand configuration, which has total costs of about 750,000€, already locates a suitable number of APLs. If the budget is lower, our approach offers alternatives for decision-makers.

SFD Promotion Initiative: Cap-Haïtien, Haiti

2021 ◽  
Author(s):  
Benjamin Biscan ◽  
Sergio Pérez Monforte ◽  
Lars Schöbitz ◽  
Anthony Kilbride
Keyword(s):  
Urban Areas ◽  
Decision Support Tool ◽  
Flow Diagram ◽  
Context Analysis ◽  
Executive Summary ◽  
Support Tool ◽  
Urban Sanitation ◽  
Key Stakeholders ◽  
Involved Field ◽  
The City

The Shit Flow Diagram (SFD) graphic is an advocacy tool that aims to assist technical and non-technical stakeholders to implement plans and programs related to urban sanitation. The SFD methodology is increasingly being used to analyze the extent of safely managed sanitation in urban areas, providing a valuable picture of the prevailing sanitation conditions, from containment to disposal. As such, it is a widely recognized advocacy and decision support tool that aims to understand, communicate, and visualize how wastewater and fecal sludge move within a city or town. As stated on the SuSanA website, the SFD methodology offers “a new and innovative way to engage sanitation experts, political leaders, and civil society in coordinated discussions about excreta management in their city”. The production and publication of an SFD report for Cap-Haitien (Haiti) would help to visualize the current sanitation situation in the city, resulting in a potential to shift current activities and efforts towards more efficient investments in the places along the sanitation chain that need more attention, improving the urban sanitation situation and the surrounding environment of the city. The structure of this SFD report consists of an executive summary and the SFD report. The latter includes: i) general city information describing its main characteristics; ii) sanitation service outcomes, with a thorough explanation of the SFD graphic outcome and the assumptions made; iii) the service delivery context analysis, which contains information on the regulatory framework of water and sanitation at country and city levels, and describes the city plans, budget and future projects to improve the sanitation situation and; iv) a detailed description of the surveys, Key Informant Interviews (KIIs) and Focus Group Discussions (FGDs) conducted, as well as the key stakeholders involved, field visits carried out and references used to develop this SFD report.

scholarly journals Water–Energy–Food Nexus Simulation: An Optimization Approach for Resource Security

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 667 ◽  
Author(s):  
Albert Wicaksono ◽  
Gimoon Jeong ◽  
Doosun Kang
Keyword(s):  
Resource Management ◽  
Simulation Models ◽  
Decision Support Tool ◽  
Limited Resources ◽  
Optimization Approach ◽  
Support Tool ◽  
Sustainable Resource Management ◽  
Novel Approach ◽  
Management Plans ◽  
Optimal Resource

The water–energy–food nexus (WEF nexus) concept is a novel approach to manage limited resources. Since 2011, a number of studies were conducted to develop computer simulation models quantifying the interlinkage among water, energy, and food sectors. Advancing a nationwide WEF nexus simulation model (WEFSiM) previously developed by the authors, this study proposes an optimization module (WEFSiM-opt) to assist stakeholders in making informed decisions concerning sustainable resource management. Both single- and multi-objective optimization modules were developed to maximize the user reliability index (URI) for water, energy, and food sectors by optimizing the priority index and water allocation decisions. In this study, the developed models were implemented in Korea to determine optimal resource allocation and management decisions under a plausible drought scenario. This study suggests that the optimization approach can advance WEF nexus simulation and provide better solutions for managing limited resources. It is anticipated that the proposed WEFSiM-opt can be utilized as a decision support tool for designing resource management plans.

Simulation optimization-based decision support tool for steel manufacturing

2013 ◽  
Vol 141 (1) ◽  
pp. 269-276 ◽  
Author(s):  
Sharif H. Melouk ◽  
Nickolas K. Freeman ◽  
David Miller ◽  
Michelle Dunning
Keyword(s):  
Decision Support ◽  
Simulation Optimization ◽  
Decision Support Tool ◽  
Support Tool ◽  
Steel Manufacturing

scholarly journals A Robust Optimization Approach to the Multiple Allocation p-Center Facility Location Problem

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 588 ◽  
Author(s):  
Bo Du ◽  
Hong Zhou
Keyword(s):  
Robust Optimization ◽  
Facility Location ◽  
Location Problem ◽  
Facility Location Problem ◽  
Optimization Approach ◽  
Robust Solutions ◽  
Demand Node ◽  
Uncertainty Sets ◽  
Ellipsoidal Uncertainty ◽  
Multiple Allocation

In this study, we apply a robust optimization approach to a p-center facility location problem under uncertainty. Based on a symmetric interval and a multiple allocation strategy, we use three types of uncertainty sets to formulate the robust problem: box uncertainty, ellipsoidal uncertainty, and cardinality-constrained uncertainty. The equivalent robust counterpart models can be solved to optimality using Gurobi. Comprehensive numerical experiments have been conducted by comparing the performance of the different robust models, which illustrate the pattern of robust solutions, and allocating a demand node to multiple facilities can reduce the price of robustness, and reveal that alternative models of uncertainty can provide robust solutions with different conservativeness.

scholarly journals Site-Scale Integrated Decision Support Tool (i-DSTss) for Stormwater Management

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2022 ◽  
Author(s):  
Shojaeizadeh ◽  
Geza ◽  
McCray ◽  
Hogue
Keyword(s):  
Decision Support ◽  
Best Management Practices ◽  
Life Cycle Cost ◽  
Management Practices ◽  
Decision Support Tool ◽  
Green Roofs ◽  
Optimization Approach ◽  
Small Catchment ◽  
Support Tool ◽  
A Site

A site-scale integrated decision support tool (i-DSTss) is developed for selection and sizing of stormwater Best Management Practices (BMPs). The tool has several component modules—hydrology, BMP selection, BMP sizing, and life-cycle cost analysis (LCCA)—integrated into a single platform. The hydrology module predicts runoff from small catchment on event and continuous basis using the Green-Ampt and Curve Number methods. The module predicted runoff from a small residential area and a parking lot with R2 value of 0.77 and 0.74, respectively. The BMP selection module recommends a BMP type appropriate for a site based on economic, technical, social and environmental criteria using a multi-criteria optimization approach. The BMP sizing module includes sizing options for green roofs, infiltration-based BMPs, and storage-based BMPs. A mass balance approach is implemented for all types of BMPs. The tool predicted outflow rates from a permeable pavement with R2 value of 0.89. A cost module is included where capital, operation and maintenance, and rehabilitation costs are estimated based on BMP size obtained from the sizing module. The i-DSTss is built on an accessible platform (Microsoft Excel VBA) and can be operated with a basic skillset. The i-DSTss is intended for designers, regulators, and municipalities for quick analysis of scenarios involving interaction among several factors.

scholarly journals A Model of Systems Dynamics for Physical Flow Analysis in a Distribution Supply Chain

2021 ◽  
Vol 22 (1) ◽  
pp. 98-108
Author(s):  
Kahina Hamoudi ◽  
Ahmed Bellaouar ◽  
Romain Petiot
Keyword(s):  
Supply Chain ◽  
Decision Support ◽  
Flow Analysis ◽  
Decision Support Tool ◽  
Flow Diagram ◽  
Systems Dynamics ◽  
Transport Costs ◽  
Support Tool ◽  
Term Operation ◽  
Distribution Logistics

AbstractThis article proposes a model of systems dynamics for the analysis and study of physical flows in a distribution logistics chain. The proposed model is a decision support tool that allows testing several scenarios in order to study the behavior of physical flows within a supply chain depending on the inventory and transport costs and taking into consideration the environmental issues through the integration of a CO2 tax in transport costs. The developed model can be used to analyze various scenarios and perform various “what-if” analyzes, as well as to answer questions about the long-term operation of distribution chains. The results show that logistic decisions and strategies taken at the supply chain level influence inventory and transport costs. They show also that the model is a well decision-support tool for calculating and analyzing transport and inventory costs. We first expose the methodology and the literature review. Next, we present in detail the structure of the model consisting of the causal loops diagram and stock and flow diagram. Finally, we discuss the results of the model.

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