An adapted version of the water wave optimization algorithm for the capacitated vehicle routing problem with time windows with application to a real case using probe data

Customers' habits, as far as shipping requests are concerned, have changed in the last decade, due to the fast spread of e-commerce and business to consumer (B2C) systems, thus generating more and more vehicles on the road, traffic congestion and, consequently, more pollution. Trying to partially solve this problem, the operational research field dedicates part of its research to possible ways to optimize transports in terms of costs, travel times, full loads etc., with the aim of reducing inefficiencies and impacts on profit, planet and people, i.e., the well-known triple bottom line approach to sustainability, also thanks to new technologies able to instantly provide probe data, which can detail information as far as the vehicle behavior. In line with this, an adapted version of the metaheuristic water wave optimization algorithm is here presented and applied to the context of the capacitated vehicle routing problem with time windows. This latter one is a particular case of the vehicle routing problem, whose aim is to define the best route in terms of travel time for visiting a set of customers, given the vehicles capacity and time constraints in which some customers need to be visited. The algorithm is then tested on a real case study of an express courier operating in the South of Italy. A nearest neighbor heuristic is applied, as well, to the same set of data, to test the effectiveness and accuracy of the algorithm. Results show a better performance of the proposed metaheuristic, which could improve the journeys by reducing the travel time by up to 23.64%

Optimization of a perishable inventory system: A simulation study in a Ho.Re.Ca. company

The main goal of this paper is to describe the optimization of the inventory management process in a real context of perishable food products. The study involves one of the largest Italian HO.RE.CA. companies, located in the north of Italy and operating as a provider of the catering, commercial and welfare services. A simulation model was set up with the purpose of adapting three traditional reordering policies (i.e. Re-Order Point, Re-Order Cycle, and (s,S)) to a set of products belonging to company's assortment and evaluating the resulting economic outcomes. To this end, each policy was modelled on Microsoft ExcelTM, so as to compute the total cost of inventory management and determine of the minimum cost strategy. A comparison with the current company's performance and that achievable with the optimized policy is also proposed

Regional probabilities of precipitation change: A Bayesian analysis of multimodel simulations

Tebaldi et al. [2005] present a Bayesian approach to determining probability distribution functions (PDFs) of temperature change at regional scales, from the output of a multi-model ensemble, run under the same scenario of future anthropogenic emissions. The main characteristic of the method is the formalization of the two criteria of bias and convergence that the REA method [Giorgi and Mearns, 2002] first quantified as a way of assessing model reliability. Thus, the General Circulation Models (AOGCMs) of the ensemble are combined in a way that accounts for their performance with respect to current climate and a measure of each model's agreement with the majority of the ensemble. We apply the Bayesian model to a set of transient experiments under two SRES scenarios. We focus on predictions of precipitation change, for land regions of subcontinental size. We highlight differences in the PDFs of precipitation change derived in regions where models find easy agreement, and perform well in simulating present day precipitation, compared to regions where models have large biases, and/or their future projections disagree. We compare results from the two scenarios, thus assessing the consequences of the two alternative hypotheses, and present summaries based on their averaging

Economic and environmental sustainability dimensions of a fashion supply chain: A quantitative model

Paper aim: The paper presents a model to assess the economic and the environmental sustainability dimensions of a fashion supply chain and tests it on a company. Originality: The gap intended to fill is the lack of models in this context having this purpose, and, in general, the necessity to develop models and metrics allowing to quantitatively assess the economic and environmental dimensions of supply chains. Research method: The fashion supply chain has been divided into five processes. Hence, an analytic model was developed by considering the total costs incurring in each process (economic evaluation), and the annual kilograms of CO2 emitted (environmental perspective). The model was then applied to a case study. Data was obtained from interviews with the management. Main findings: Results show that from the economic perspective supply impacts the most, while from the environmental one the most polluting activity is production. Implications for theory and practice: The model is easy to apply and to understand and allows to identify the activities in the supply chain where the majority of costs/emissions are generated. It is therefore expected to be useful for undertaking operational decisions aimed at decreasing the economic or environmental impact of a fashion supply chain

An Analytic Model for Estimating the Economic and Environmental Impact of Food Cold Supply Chain

Cold chain management has gained increasing interest among practitioners, researchers and academics; similarly, sustainability is also proving to be an increasingly critical topic in all supply chains and in cold chains in particular. In line with this, this study proposes a model to estimate the economic and environmental impacts in a food cold supply chain (FCSC). The model intended to estimate the total cost and CO2 emissions of a company operating in the cold supply chain, was carried out in Microsoft Excel™. Specifically, the model reproduces the main FCSC processes, i.e., Product collection, Backroom storage, Product delivery and Reverse logistics. For each process, we have exposed the implemented equations. Results show that the product delivery process is the most critical in both economic and environmental terms. Conversely, product collection and reverse logistics process contribute to the total cost and emission to a limited extent. The results obtained provide useful guidelines for supply chain managers to undertake operation decisions aimed at decreasing the economic and/or environmental impact of a FCSC

A model for assessing economic and environmental sustainability dimensions of a fashion supply chain and a case study

Due to the recent attention gained by sustainability issues in the context of supply chains, the aim of this study is to present a model developed under Microsoft Excel™ for the assessment of the economic and environmental dimensions of a fashion supply chain, sector that deserves particular attention being one of the most polluting in the world. The assessment of the economic dimension is made through the evaluation of the total cost incurred in each process of the supply chain, while the environmental aspect is evaluated in terms of the carbon dioxide emissions generated. Specifically, in this paper the modelling of the warehouse function is detailed. To test the effectiveness of the model a case study is carried out on a fashion company based in the North of Italy; the key results are reported in the manuscript, showing where the majority of costs and emissions are generated. Information obtained from this tool can support the company's management in their operational decisions and show where to focus their attention to enhance the economic and environmental sustainability

A storage assignment simulation model for optimizing processes in an e-commerce warehouse of a fashion supply chain

The wide spread of e-commerce and in general B2C systems brought new challenges to supply chains which had to reconsider part of their systems whilst maintaining the same goal: a high level of customer satisfaction. One of the main functions affected by these challenges is the logistics activity, including warehouse management and transports. Indeed, they now have to face higher orders at the same time, to manage picks demand in specified periods, to increase journeys for reaching various customers geographically dispersed. Optimization and synchronization are essential. To this end and according to the steps of the Deming Cycle, this paper presents the case of a warehouse located in northern Italy whose storage activity was firstly simulated and then successfully implemented so as to optimize the picking activity and consequently the subsequent processes of the outbound flow. Improvements were assessed through determined key performance indicators, monitored before and after the implementation of the new strategy

Assessment of the economic and environmental sustainability of a food cold supply chain

Based on environmental and economic factors, reverse logistics (RL) issues have attracted attention among both academia and practitioners. This study investigates the issue of economic and environmental sustainability evaluation in a food cold supply chain (FCSC), which carries out four main different processes, i.e. product collection, backroom storage, products delivery and RL. For the RL process, which is taken as an example, we have detailed the equations implemented in an analytic model to carry out the computation of the economic and environmental sustainability, while for the remaining processes, we present and discuss only the main results obtained. The model was developed under Microsoft Excel™ and is intended to assess the total cost and CO2 emissions of an important company operating as a cold chain logistics service provider. Results of the model show that the highest total cost and environmental impact are due to the product delivery process. Moreover, the results proposed indicate quite clearly the specific activity component where the FCSC managers should intervene to remove or decrease possible inefficiencies and optimize or increase the sustainability of a FCSC

Capacitated vehicle routing problem with time windows: A linear model and a case study of express courier

Given the importance gained by the e-commerce field in the recent years, this study investigates the issue of minimizing the delivery travel time of a real company located in the South of Italy and operating as a courier, express and parcel (CEP) service provider. The scenario under examination consists of a depot, three vehicles and several customers served by the CEP company. A Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) model is formulated to optimize the deliveries to the customers for the targeted company and solved under the commercial software IBM ILOG CPLEX Optimization Studio. As outcomes, the model returns a simulated path covered by the vehicles and computes the corresponding travel time. Results show that with the proposed formulation, the time windows (TWs) of all customers are respected. Because the analysis is grounded on a real company, the results are expected to provide practical indications to logistics and supply chain managers, to maximize the performance of their delivery system

Metodologia Diagnóstica para as Unidades de Conservação Estaduais do Espírito Santo: Condições para sua Gestão, Prevenção e Combate aos Incêndios Florestais.

TEBALDI, André Luiz Campos. Metodologia Diagnóstica para as Unidades de Conservação Estaduais do Espírito Santo: Condições para sua Gestão e para Prevenção e Combate aos Incêndios Florestais. 2010. Dissertação (Mestrado em Ciências Florestais) Universidade Federal do Espírito Santo, Alegre ES. Orientador Prof. Dr. Nilton César Fiedler. A pesquisa teve o objetivo principal desenvolver metodologia diagnóstica para as Unidades de Conservação estaduais do Espírito Santo: Condições para sua gestão, prevenção e combate aos incêndios florestais. Buscou-se trabalhar com seis objetivos específicos sendo eles: caracterizar as condições de gestão e infraestrutura; diagnosticar a disponibilidade quantitativa de pessoal e equipamentos para prevenção e combate aos incêndios florestais; identificar os principais grupos de causa das ocorrências de incêndios florestais relacionando-as com as principais ameaças aos ecossistemas; identificar a distribuição das classes de tamanho das áreas queimadas, identificar os principais tipos de incêndios; diagnosticar as principais atividades de prevenção desenvolvidas. A análise contou com a participação de todos os gestores das dezesseis Unidades de Conservação estaduais criadas até o ano de 2009. Os resultados indicaram que a Reserva Biológica de Duas Bocas possui melhores condições para gestão e infraestrutura (82%) e a Reserva de Desenvolvimento Sustentável Concha Dostra possui piores condições (5%). O Parque Estadual de Itaúnas apresentou maior déficit de pessoal. Na disponibilidade de equipamentos operacionais, observou-se que 75% das Unidades de proteção integral estão com déficit. Na relação de ferramentas identificou-se que o Parque Estadual da Cachoeira da Fumaça apresentou o maior déficit e não há equipamentos de proteção individual nas Unidades. A infraestrutura inadequada (14%) e a caça (12%) são as principais ameaças às Unidades estaduais. Mais de 50% dos incêndios nas Unidades estaduais são de superfície com predominância de área queimada variando de 0,1 à 40 hectares. Aproximadamente 40% das causas são queimas para limpeza e 20% incendiários. As principais atividades preventivas realizadas são integração interinstitucional e vigilância da unidade (22%). Os resultados servirão como uma eficiente ferramenta de planejamento e gestão para o Governo do Estado implementar ações e atividades preventivas nas Unidades de Conservação. Palavras chave: Meio Ambiente, Área Natural Protegida, Gestão de Unidades de Conservação, Prevenção e Combate aos Incêndios Florestais