scholarly journals The Colombian Strategic Freight Transport Model Based on Product Analysis

2014 ◽  
Vol 26 (6) ◽  
pp. 487-496 ◽  
Author(s):  
Victor Cantillo ◽  
Miguel Jaller ◽  
Jose Holguín-Veras
Keyword(s):  
Transport Model ◽  
Freight Transport ◽  
Product Analysis ◽  
Transport Modelling ◽  
Modelling Framework ◽  
Proposed Model ◽  
Data Limitations ◽  
Relevant Variables ◽  
Freight Modelling

Freight transport modelling at interregional scale is relevant for planning issues. However, freight modelling processes are complex because it is not easy to define the relevant variables in the analysis, and to obtain the required information on freight movements through the network. These facts raise the need to adapt the modelling framework to each context.This paper proposes a strategic national freight transport modelling framework developed as a variant of the traditional four-step modelling process with additional steps to estimate traffic flows from freight flows and to consider empty trips. The country of Colombia is used as the case study to implement and calibrate the proposed model. The data, data sources, and modelling methodologies used for each step are explained. In addition, data limitations and measures taken to complement the available data are discussed. From the implementation, the authors identify a set of advantages derived from the modelling approaches considered and suggestions for improvement.

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 Influence of Chemical Osmosis on Solute Transport and Fluid Velocity in Clay Soils

2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han
Keyword(s):  
Solute Transport ◽  
Transport Model ◽  
Fluid Velocity ◽  
Diffusion Mechanism ◽  
Clay Material ◽  
Chemical Osmosis ◽  
Advection Diffusion Equation ◽  
Test Study ◽  
Proposed Model ◽  
Membrane Effect

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.

scholarly journals Scenario Analyses of Exhaust Emissions Reduction through the Introduction of Electric Vehicles into the City

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 2030
Author(s):  
Marianna Jacyna ◽  
Renata Żochowska ◽  
Aleksander Sobota ◽  
Mariusz Wasiak
Keyword(s):  
Inner City ◽  
Electric Vehicles ◽  
Transport Model ◽  
Exhaust Emissions ◽  
Scenario Analyses ◽  
High Emission ◽  
Clean Air ◽  
The One ◽  
The City

In recent years, policymakers of urban agglomerations in various regions of the world have been striving to reduce environmental pollution from harmful exhaust and noise emissions. Restrictions on conventional vehicles entering the inner city are being introduced and the introduction of low-emission measures, including electric ones, is being promoted. This paper presents a method for scenario analysis applied to study the reduction of exhaust emissions by introducing electric vehicles in a selected city. The original scenario analyses relating to real problems faced by contemporary metropolitan areas are based on the VISUM tool (PTV Headquarters for Europe: PTV Planung Transport Verkehr AG, 76131 Karlsruhe, Germany). For the case study, the transport model of the city of Bielsko-Biala (Poland) was used to conduct experiments with different forms of participation of electric vehicles on the one hand and traffic restrictions for high emission vehicles on the other hand. Scenario analyses were conducted for various constraint options including inbound, outbound, and through traffic. Travel time for specific transport relations and the volume of harmful emissions were used as criteria for evaluating scenarios of limited accessibility to city zones for selected types of vehicles. The comparative analyses carried out showed that the introduction of electric vehicles in the inner city resulted in a significant reduction in the emission of harmful exhaust compounds and, consequently, in an increase in the area of clean air in the city. The case study and its results provide some valuable insights and may guide decision-makers in their actions to introduce both driving ban restrictions for high-emission vehicles and incentives for the use of electric vehicles for city residents.

Product Analysis and Variants Derivation Based on a Semantically Annotated Product Family Ontology

2009 ◽  
Author(s):  
Soon Chong Johnson Lim ◽  
Ying Liu ◽  
Wing Bun Lee
Keyword(s):  
Semantic Annotation ◽  
Product Family ◽  
Relevant Information ◽  
Product Analysis ◽  
Laptop Computer ◽  
Family Analysis ◽  
Design And Manufacturing ◽  
Commonality Analysis ◽  
Current Representation

In literature, there are a number of indexes suggested that serve as the indicator of commonality among product components, modules and variants. However, as these elements are increasingly interconnected with aspects other than the component view, the existing commonality metrics are unable to effectively model these aspects due to their limitation in capturing relevant information for analysis. Therefore, there exists a need to consider multiple design and manufacturing aspects in commonality metrics so that a comprehensive view of the commonality among product variants can be presented. In the current representation schemes proposed for product family modeling, ontology is one of the most promising ones to model the complex semantic relations among various elements in a product family. Nevertheless, the research and application of ontology in the analysis of a product family has so far received little attention. In this paper, we proposed a framework to generate a semantically annotated multi-facet product family ontology. Using a case study of a laptop computer family, we suggest and demonstrate a new commonality analysis approach based on the semantically annotated multi-facet laptop product family ontology. Together with a new method of deriving product variants based on the aforementioned ontology, our approach illustrates the merits of using semantic annotation in assisting ontology based product family analysis.

scholarly journals A New Approach to Inform Restoration and Management Decisions for Sustainable Apiculture

2021 ◽  
Vol 13 (11) ◽  
pp. 6109
Author(s):  
Joanne Lee Picknoll ◽  
Pieter Poot ◽  
Michael Renton
Keyword(s):  
Floral Resources ◽  
Pollination Services ◽  
New Approach ◽  
Honey Production ◽  
Proposed Model ◽  
Colony Loss ◽  
Supply Potential ◽  
Australian Case ◽  
Stocking Rates

Habitat loss has reduced the available resources for apiarists and is a key driver of poor colony health, colony loss, and reduced honey yields. The biggest challenge for apiarists in the future will be meeting increasing demands for pollination services, honey, and other bee products with limited resources. Targeted landscape restoration focusing on high-value or high-yielding forage could ensure adequate floral resources are available to sustain the growing industry. Tools are currently needed to evaluate the likely productivity of potential sites for restoration and inform decisions about plant selections and arrangements and hive stocking rates, movements, and placements. We propose a new approach for designing sites for apiculture, centred on a model of honey production that predicts how changes to plant and hive decisions affect the resource supply, potential for bees to collect resources, consumption of resources by the colonies, and subsequently, amount of honey that may be produced. The proposed model is discussed with reference to existing models, and data input requirements are discussed with reference to an Australian case study area. We conclude that no existing model exactly meets the requirements of our proposed approach, but components of several existing models could be combined to achieve these needs.

Elastic Averaging in Flexure Mechanisms: A Muliti-Beam Parallelogram Flexure Case-Study

2006 ◽  
Author(s):  
Shorya Awtar ◽  
Edip Sevincer
Keyword(s):  
Mechanism Design ◽  
Parametric Model ◽  
Nonlinear Load ◽  
Geometric Imperfections ◽  
Geometric Imperfection ◽  
Flexure Mechanism ◽  
Important Concern ◽  
Proposed Model ◽  
Geometric Arrangements

Over-constraint is an important concern in mechanism design because it can lead to a loss in desired mobility. In distributed-compliance flexure mechanisms, this problem is alleviated due to the phenomenon of elastic averaging, thus enabling performance-enhancing geometric arrangements that are otherwise unrealizable. The principle of elastic averaging is illustrated in this paper by means of a multi-beam parallelogram flexure mechanism. In a lumped-compliance configuration, this mechanism is prone to over-constraint in the presence of nominal manufacturing and assembly errors. However, with an increasing degree of distributed-compliance, the mechanism is shown to become more tolerant to such geometric imperfections. The nonlinear load-stiffening and elasto-kinematic effects in the constituent beams have an important role to play in the over-constraint and elastic averaging characteristics of this mechanism. Therefore, a parametric model that incorporates these nonlinearities is utilized in predicting the influence of a representative geometric imperfection on the primary motion stiffness of the mechanism. The proposed model utilizes a beam generalization so that varying degrees of distributed compliance are captured using a single geometric parameter.

Measuring Performance of a Three-Stage Network Structure Using Data Envelopment Analysis and Nash Bargaining Game: A Supply Chain Application

2018 ◽  
Vol 17 (05) ◽  
pp. 1429-1467 ◽  
Author(s):  
Mohammad Amirkhan ◽  
Hosein Didehkhani ◽  
Kaveh Khalili-Damghani ◽  
Ashkan Hafezalkotob
Keyword(s):  
Supply Chain ◽  
Data Envelopment Analysis ◽  
Nash Bargaining ◽  
Data Envelopment ◽  
Second Stage ◽  
Proposed Model ◽  
Nash Bargaining Game ◽  
Dea Models ◽  
Overall Efficiency

The issue of efficiency analysis of network and multi-stage systems, as one of the most interesting fields in data envelopment analysis (DEA), has attracted much attention in recent years. A pure serial three-stage (PSTS) process is a specific kind of network in which all the outputs of the first stage are used as the only inputs in the second stage and in addition, all the outputs of the second stage are applied as the only inputs in the third stage. In this paper, a new three-stage DEA model is developed using the concept of three-player Nash bargaining game for PSTS processes. In this model, all of the stages cooperate together to improve the overall efficiency of main decision-making unit (DMU). In contrast to the centralized DEA models, the proposed model of this study provides a unique and fair decomposition of the overall efficiency among all three stages and eliminates probable confusion of centralized models for decomposing the overall efficiency score. Some theoretical aspects of proposed model, including convexity and compactness of feasible region, are discussed. Since the proposed bargaining model is a nonlinear mathematical programming, a heuristic linearization approach is also provided. A numerical example and a real-life case study in supply chain are provided to check the efficacy and applicability of the proposed model. The results of proposed model on both numerical example and real case study are compared with those of existing centralized DEA models in the literature. The comparison reveals the efficacy and suitability of proposed model while the pitfalls of centralized DEA model are also resolved. A comprehensive sensitivity analysis is also conducted on the breakdown point associated with each stage.

scholarly journals Performance assessment of alternative SSS networks by combining KPIs and factor-cluster analysis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Patrizia Serra ◽  
Gianfranco Fancello
Keyword(s):  
Cluster Analysis ◽  
Performance Assessment ◽  
Decision Support Tool ◽  
Transport Systems ◽  
Quantitative Methodology ◽  
Support Tool ◽  
Performance Benchmarking ◽  
Relevant Variables ◽  
Quantitative Results

Abstract Performance assessment is a fundamental tool to successfully monitor and manage logistics and transport systems. In the field of Short Sea Shipping (SSS), the performance of the various maritime initiatives should be analyzed to assess the best way to achieve efficiency and guide related policies. This study proposes a quantitative methodology which can serve as a decision-support tool in the preliminary assessment and comparison of alternative SSS networks. The research is executed via a Mediterranean case study that compares a hypothetical Mediterranean ro-ro SSS network developed in the framework of a past Euro-Mediterranean cooperation project with the network of existing ro-ro liner services operating in the area. Performance benchmarking of the two networks is performed using a set of quantitative Key Performance Indicators (KPIs) and applying a factor-cluster analysis to produce homogeneous clusters of services based on the relevant variables while accounting for sample heterogeneity. Quantitative results mostly confirm the overall better performance of the prospective network and demonstrate that using KPIs and factor-cluster analysis to investigate the performance of maritime networks can provide policymakers with a preliminary wealth of knowledge that can help in setting targeted policy for SSS-oriented initiatives.

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