Since the introduction of sustainable development, industries have witnessed significant sustainability challenges. Literature shows that the food industry is concerned about its need for efficient and effective management practices in dealing with perishability and the requirements for conditioned storage and transport of food products that effect the environment. Hence, the environmental part of sustainability demonstrates its significance in this industrial sector. Despite this, there has been little research into environmentally sustainable inventory management of deteriorating items. This thesis presents mathematical modelling based research for production inventory systems in perishable food supply chains. In this study, multi-objective mixed-integer linear programming models are developed to determine economically and environmentally optimal production and inventory decisions for a two-echelon supply chain. The supply chain consists of single sourcing suppliers for raw materials and a producer who operates under a make-to-stock or make-to-order strategy. The demand facing the producer is non-stationary stochastic in nature and has requirements in terms of service level and the remaining shelf life of the marketed products. Using data from the literature, numerical examples are given in order to test and analyse these models. The computational experiments show that operational adjustments in cases where emission and cost parameters were not strongly correlated with supply chain collaboration (where suppliers and a producer operate under centralised control), emissions are effectively reduced without a significant increase in cost. The findings show that assigning a high disposal cost, limit or high weight of importance to perished goods leads to appropriate reduction of expected waste in the supply chain with no major cost increase. The research has made contributions to the literature on sustainable production and inventory management; providing formal models that can be used as an aid to understanding and as a tool for planning and improving sustainable production and inventory control in supply chains involving deteriorating items, in particular with perishable food supply chains.

Nessa dissertação apresentamos um problema de programação da produção, motivado por uma indústria alimentícia caracterizada pela perecibilidade dos produtos, sequenciamento da produção dos lotes e pela necessidade de sincronização de recursos escassos para operação das linhas de produção. Em indústrias desse ramo, existem altos custos associados a estocagem dos produtos, a fim de evitar sua perda, de modo que é essencial a boa gestão dos processos industriais e do estoque. Modelos matemáticos de programação inteira mista foram desenvolvidos para tratar o problema, bem como o estudo da inclusão de diversas restrições da literatura para o tratamento da perecibilidade. Testes computacionais foram realizados para as validações dos modelos matemáticos, entretanto, devido à dificuldade de determinar soluções de boa qualidade pelo solver de otimização, foram propostos métodos heurísticos baseados na formulação matemática. Com o objetivo de mostrar o desempenho das heurísticas, comparamos as suas performances na resolução de instâncias da literatura e exemplares baseados no cenário produtivo da indústria com os resultados do solver. / In this dissertation we present a lot sizing and scheduling problem motivated by a food industry characterized by the perishability of the products, sequencing the production of the lots and by the need of synchronization of scarce resources for the operation of the production lines. In this type of industry, there are high costs associated with stocking the products in order to avoid their loss, so that good management of industrial processes and inventory is essential. Mathematical models of mixed integer programming were developed to treat the problem, as well as the study of the inclusion of several restrictions of the literature for the treatment of perishability. Computational tests were performed for the validations of the mathematical models, however, due to the difficulty of determining solutions of good quality by the optimization solver, heuristic methods based on the mathematical formulation were proposed. In order to show the performance of the heuristics, we compare their performances in solving instances of the literature and exemplars based on the productive scenario of the industry with the results of solver.

Nessa dissertação apresentamos um problema de programação da produção, motivado por uma indústria alimentícia caracterizada pela perecibilidade dos produtos, sequenciamento da produção dos lotes e pela necessidade de sincronização de recursos escassos para operação das linhas de produção. Em indústrias desse ramo, existem altos custos associados a estocagem dos produtos, a fim de evitar sua perda, de modo que é essencial a boa gestão dos processos industriais e do estoque. Modelos matemáticos de programação inteira mista foram desenvolvidos para tratar o problema, bem como o estudo da inclusão de diversas restrições da literatura para o tratamento da perecibilidade. Testes computacionais foram realizados para as validações dos modelos matemáticos, entretanto, devido à dificuldade de determinar soluções de boa qualidade pelo solver de otimização, foram propostos métodos heurísticos baseados na formulação matemática. Com o objetivo de mostrar o desempenho das heurísticas, comparamos as suas performances na resolução de instâncias da literatura e exemplares baseados no cenário produtivo da indústria com os resultados do solver. / In this dissertation we present a lot sizing and scheduling problem motivated by a food industry characterized by the perishability of the products, sequencing the production of the lots and by the need of synchronization of scarce resources for the operation of the production lines. In this type of industry, there are high costs associated with stocking the products in order to avoid their loss, so that good management of industrial processes and inventory is essential. Mathematical models of mixed integer programming were developed to treat the problem, as well as the study of the inclusion of several restrictions of the literature for the treatment of perishability. Computational tests were performed for the validations of the mathematical models, however, due to the difficulty of determining solutions of good quality by the optimization solver, heuristic methods based on the mathematical formulation were proposed. In order to show the performance of the heuristics, we compare their performances in solving instances of the literature and exemplars based on the productive scenario of the industry with the results of solver.

The blood supply chain, starting from the donor until the blood is used to meet transfusion demands of patients, is a multi-echelon and complex system. The perishable and lifesaving characteristics of blood products, such as red blood cells and platelets, as well as uncertainties in both supply and demand make it difficult to maintain a balance between shortage and wastage due to expiry. An effective blood supply chain should be able to meet the demand while at the same time reducing wastage and total operational cost. In order to be cost effective, the related organizations have to decide how much blood should be collected from donors, how much blood products should be produced at the blood center, and how much blood products should be distributed to hospitals or transshipped between hospitals. The objective of this dissertation is to provide these tactical and operational decisions to guide those who work in healthcare supply chain management and explore new opportunities on performance improvement for an integrated blood supply chain by optimization with aim of minimizing total cost, consideration of transshipment between hospitals, and application of a coordinated multi-product model. This dissertation presents three multi-stage stochastic models for an integrated blood supply chain to minimize total cost incurred in the collection, production, inventory, and distribution echelons under centralized control. The scope of this study focuses on modeling a supply chain of blood products in one regional blood center, several hospitals and blood collection facilities. First, we develop an integrated model for the platelet supply chain that accounts for demand uncertainty and blood age information, then we develop this model further by investigating the impact of transshipment between hospitals on cost savings, and then we propose a multi-product model that accounts for red blood cells and platelets at the same time and compare it with an uncoordinated model where the red blood cell and platelet supply chains are considered separately.

Made available in DSpace on 2016-04-25T16:44:37Z (GMT). No. of bitstreams: 1 Leandro Ortigoza Martins.pdf: 2024505 bytes, checksum: 84de1edbfa0bb3e9b74e0df2d49c6cdb (MD5) Previous issue date: 2013-11-07 / The diagnostic medical services are perishable and the demand is variable. These are characteristics that struggle the maximization of results. Service providers traditionally offer exams through a scheduling system without overcoming, however, the inefficiency provoked by clients no-show. This study aims at investigating consumer satisfaction levels of the diagnostic medical services in relation to the operational model of scheduling, the acceptance to a new model with no scheduling need (free on demand) and analyzing three secondary dimensions common to the two models. The literature review embraced the historical evolution of the diagnostic medical services in Brazil, as well as the processes, opportunities and challenges associated with said development. It was verified that the existing relationship between perishability and seasonality jeopardizes company profitability due to the fact that it hinders a better use of the installed capacity, dilution of expenses and return on investment. The stage relative to the evolution of services and relationship marketing evidenced the importance of carrying out a survey with the own users of the services. Such research has a quantitative approach with a descriptive exploratory outline, and it was performed in 2.545 customers of a private company of diagnostic medical services in 2013. The data collection took place by applying a questionnaire and the following statistics techniques were adopted to assess the results: average comparisons, relationship between categorical variables (χ2), clusters building, factorial vectors and analysis of independent items. The results of the secondary dimensions (no show, seasonality and waiting time) have indicated that the subjects are engaged to avoid the no-show practice, trend to go to Establishments according to the present seasonality and are sensitive to waiting time. Pursuant to the main dimensions (scheduling and free on demand systems), it was detected different levels of acceptance, which may indicate in principle that the two systems are complementary and does not exclude each other. Therefore, it seems to be viable the adoption of a hybrid model in the referred operation, under which the offer of medical exams would occur through the use of the two systems so that customers could make their choice as preferred / Os serviços de medicina diagnóstica são perecíveis e a demanda é variável, características que dificultam a maximização dos resultados. Os prestadores tradicionalmente ofertam os exames por meio do sistema de agendamento de horário sem, no entanto, superar a ineficiência provocada pelo não comparecimento dos clientes (no show). O objetivo desse estudo foi investigar o nível de satisfação dos consumidores de medicina diagnóstica relativamente ao modelo operacional com agendamento, a aceitação para um novo modelo sem necessidade de agendar horário (demanda livre) e analisar três dimensões secundárias comuns aos dois modelos. A revisão da literatura contemplou a evolução histórica dos serviços diagnósticos no Brasil, bem como os processos, oportunidades e desafios associados a tal desenvolvimento. Verificou-se que a relação existente entre a perecibilidade e a sazonalidade compromete a rentabilidade das empresas, pois impede o melhor aproveitamento da capacidade instalada, a diluição das despesas e o retorno dos investimentos. A etapa referente à evolução do marketing de serviços e relacionamento evidenciou a importância de realizar a pesquisa com os próprios usuários do serviço. Trata-se de uma pesquisa de abordagem quantitativa com delineamento exploratório-descritivo, realizada com 2.545 clientes de uma empresa privada de medicina diagnóstica em 2013. A coleta de dados ocorreu por meio da aplicação de questionário e foram utilizadas as seguintes técnicas estatísticas para a apuração dos resultados: comparação de médias, relações entre variáveis categóricas (χ2), construção de Clusters, vetores fatoriais e análise de itens independentes. Os resultados das dimensões secundárias (no show, sazonalidade e tempo de espera) indicaram que os sujeitos estão engajados para evitar a prática do no show, tendem a frequentar os estabelecimentos conforme a sazonalidade atual e são sensíveis à espera. Quanto às dimensões principais (sistema com agendamento e sistema com demanda livre), foram evidenciados diferentes níveis de aceitação, o que indica, a princípio, que os dois sistemas são complementares e não excludentes. Assim, parece viável a adoção de um modelo híbrido de operação, no qual a oferta dos exames se daria pela utilização dos dois sistemas para que os clientes optem conforme a preferência

Abstract. In the worldview of a traditionally Eastern cultural context, consciousness and matter are intertwined.  In that context  negative and positive spaces relate to each other. With that in mind, the vessel is an interesting object to work with. In my master work I explore "Thinking- through- making", a process where making and thinking alternate back and forth, in iterations. The making or designing can be taking place intuitively.  Scaling down the vessel, to the point where it has no contemporary practical function,  as a way of talking about the exercise of sensitivity, in a fast, loud and insatiable present. Questioning the prevailing value system. By re:learning to become more sensitive, empathy for different types of existence becomes possible, and togetherness between human beings and their companion species opens up. By making (diminutive) stoneware vessels, I enter a long tradition of the time-consuming, hand-building technique of Yixing clay. And hence, contrasts with the technology and scale of contemporary mass production.  Perhaps my vessels are pots to plant seeds for the hope of a future human existence? Or, maybe they are vessels for tears, over human existence? At least they are parts of bedrock coming back together from dissolution, for union.

The Lack of Homogeneity in the Product (LHP) appears in productive processes with raw materials, which directly stem from nature and/or production processes with operations that confer heterogeneity to the characteristics of the outputs obtained, even when the inputs used are homogeneous. LHP appears in different sectors such as ceramic tile, horticulture, marble, snacks, among others. LHP becomes a managerial problem when customers require to be served with homogeneous product. Supply chains responsible to provide homogeneous product face the need to include classification activities in their productive processes to obtain sub-lots of homogeneous product. Due to the inherent LHP uncertainty, these homogeneous sub-lots will not be known until the product have been produced and classified. An improper management of the LHP can have a very negative impact on the customers' satisfaction due to inconsistencies in the answer to their requirements and also on the Supply Chain's efficiency. The Order Promising Process (OPP) appears as a key element for properly managing the LHP in order to ensure the matching of uncertain homogeneous supply with customer order proposals. The OPP refers to the set of business activities that are triggered to provide a response to the orders from customers. These activities are related to the acceptance/rejection decision, and to set delivery dates. For supply chains affected by the LHP, the OPP must consider the homogeneity as another requirement in the answer to the orders. Besides, due to the LHP inherent uncertainty, discrepancies between the real and planned homogeneous quantities might provoke that previously committed orders cannot be served. The Shortage Planning (SP) process intends to find alternatives in order to minimise the negative impact on customers and the supply chain. Considering LHP in the OPP brings a set of new challenging features to be addressed. The conventional approach of assuming homogeneity in the product for the master production schedule (MPS) and the quantities Available-To-Promise (ATP) derived from it is no longer adequate. Instead, both the MPS and ATP should be handled in terms of homogeneous sub-lots. Since the exact quantity of homogeneous product from the planned lots in the MPS is not exactly known until the classification activities have been performed, the ATP also inherits this uncertainty, bringing a new level of complexity. Non-homogeneous product cannot be accumulated in order to fulfil future incoming orders. Even more, if the product handled is perishable, the homogeneity management becomes considerably more complex. This is because the state of the product is dynamic with time and related variables to it, like quality, price, etc., could change with time. This situation could bring unexpected wasting costs apart from the shortages already mentioned. The perishability factor is itself another source of uncertainty associated to the LHP. This dissertation proposes a conceptual framework and different mathematical programming models and tools, in both deterministic and uncertainty environments, in order to support the OPP and SP under LHP's effect. The aim is to provide a reliable commitment with customer orders looking for a high service level not just in the due date and quantity but also in the homogeneity requirements. The modelling of the characteristics inherent to LHP under deterministic context constitutes itself one of the main contribution of this dissertation. Another novelty consists in the inclusion of uncertainty in the definition of homogeneous sub-lots, their quantities and their dynamic state and value. The uncertainty modelling approach proposed is mainly based on the application of fuzzy set theory and possibility theory. The proposed mathematical models and tools have been validated in real cases of SC, specifically in the ceramic tile sector for non perishables, and in the fruit sector for perishables. The results show a ... / La Falta de Homogeneidad en el Producto (LHP, por sus siglas del inglés ``Lack of Homogeneity in the Product'') aparece en procesos productivos con materias primas que derivan directamente de la naturaleza y/o procesos de producción con operaciones que confieren heterogeneidad a las características de los productos obtenidos, incluso cuando los insumos utilizados son homogéneos. La LHP aparece en diferentes sectores como la cerámica, horticultura, mármol, snacks, entre otros. Se convierte en un problema gerencial cuando los clientes requieren homogeneidad en el producto y las cadenas de suministro enfrentan la necesidad de incluir actividades de clasificación en sus procesos productivos para obtener sub-lotes de producto homogéneo. Debido a la incertidumbre inherente a la LHP, los sub-lotes homogéneos y su cantidad no serán conocidos hasta que el producto haya sido producido y clasificado. Una gestión inadecuada de la LHP puede tener un impacto muy negativo en la satisfacción de los clientes debido a inconsistencias en la respuesta a sus requerimientos y también en la eficacia de la Cadena de Suministro. El Proceso de Comprometer de Pedido (OPP, por sus siglas del inglés ``Order Promising Process'') aparece como un elemento clave para gestionar adecuadamente la LHP, con el fin de asegurar la coincidencia entre el suministro incierto de producto homogéneo y las propuestas de pedido del cliente. El OPP se refiere al conjunto de actividades empresariales realizadas para proporcionar una respuesta a las órdenes de los clientes. Estas actividades están relacionadas con las decisiones de aceptación/rechazo, y establecimiento de fechas de entrega para las órdenes del cliente. En las cadenas de suministro afectadas por la LHP, el OPP debe considerar la homogeneidad como otro requisito adicional en la respuesta a los pedidos. Además, debido a la incertidumbre intrínseca de la LHP, las discrepancias entre las cantidades homogéneas reales y planificadas podrían provocar que las órdenes comprometidas anteriormente no puedan ser completadas debido a la escasez de producto. El proceso de planificación de la escasez (SP, por sus siglas del inglés "Shortage Planning") se encarga de encontrar alternativas para minimizar este impacto negativo en los clientes y la cadena de suministro. Considerar la LHP dentro del OPP implica un conjunto nuevo de características desafiantes que deben ser abordadas. El enfoque convencional de asumir la homogeneidad en el producto para el programa maestro de producción (MPS, por sus siglas del inglés "Master Production Schedule") y las cantidades disponibles a comprometer (ATP, por sus siglas del inglés "Available-To-Promise") derivadas de él, no es adecuado. En cambio, tanto el MPS como el ATP deben manejarse en términos de sub-lotes homogéneos. Dado que la cantidad exacta de producto homogéneo de los lotes previstos en el MPS no se sabe exactamente hasta que se han realizado las actividades de clasificación, el ATP también hereda esta incertidumbre, trayendo un nuevo nivel de complejidad. El producto no homogéneo no se puede acumular para satisfacer futuras órdenes entrantes. Más aún, si el producto manipulado es perecedero, el manejo de la homogeneidad se vuelve mucho más complejo. Esto se debe a que el estado del producto es dinámico en el tiempo, y variables relacionadas como calidad, precio, etc., podrían también cambiar con el tiempo. Esta situación puede provocar costos inesperados de desperdicio aparte de la escasez ya mencionada. El factor de perecedero es en sí mismo otra fuente de incertidumbre asociada a la LHP. Esta disertación propone un marco conceptual y diferentes modelos y herramientas de programación matemática, tanto en entornos deterministas como de incertidumbre, para apoyar al OPP y SP considerando el efecto de LHP. El objetivo es proporcionar un compromiso fiable con los pedidos de los clientes en busca de un alto nivel de servicio no s / La Falta d'Homogeneïtat en el Producte (LHP, per les seues sigles de l'anglés ''Lack of Homogeneity in the Product'') apareix en processos productius amb matèries primes que deriven directament de la natura i/o processos de producció amb operacions que conferixen heterogeneïtat a les característiques dels productes obtinguts, fins i tot quan les entrades utilitzades són homogènies . La LHP apareix en diferents sectors com la ceràmica, horticultura, marbre, snacks, entre altres. Es convertix en un problema gerencial quan els clients requereixen homogeneïtat en el producte i les cadenes de subministrament enfronten la necessitat d'incloure activitats de classificació en els seus processos productius per a obtindre sublots de producte homogeni. A causa de la incertesa inherent a la LHP, els sublots homogenis i la seua quantitat no seran coneguts fins que el producte haja sigut produït i classificat. Una gestió inadequada de la LHP pot tindre un impacte molt negatiu en la satisfacció dels clients degut a inconsistències en la resposta als seus requeriments i també en l'eficàcia de la Cadena de Subministrament. El Procés de Comprometre Comandes (OPP, per les seues sigles de l'anglés ''Order Promising Process'') apareix com un element clau per a gestionar adequadament la LHP, a fi d'assegurar la coincidència entre el subministrament incert de producte homogeni i les propostes de comanda del client. L'OPP es refereix al conjunt d'activitats empresarials realitzades per a proporcionar una resposta a les ordres dels clients. Aquestes activitats estan relacionades amb les decisions d'acceptació/rebuig, i establiment de dates de lliurament per a les ordres del client. En les cadenes de subministrament afectades per la LHP, l'OPP ha de considerar l'homogeneïtat com un altre requisit addicional en la resposta a les comandes. A més, a causa de la incertesa intrínseca de la LHP, les discrepàncies entre les quantitats homogènies reals i planificades podrien provocar que les ordres compromeses anteriorment no puguen ser completades a causa de l'escassetat de producte. El procés de planificació de l'escassetat (SP, per les seues sigles de l'anglés "Shortage Planning") s'encarrega de trobar alternatives per a minimitzar aquest impacte negatiu en els clients i en la cadena de subministrament. Considerar la LHP dins de l'OPP implica un conjunt nou de característiques desafiants que han de ser abordades. L'enfocament convencional d'assumir l'homogeneïtat en el producte per al programa mestre de producció (MPS, per les seues sigles de l'anglés "Master Production Schedule") i les quantitats disponibles a comprometre (ATP, per les seues sigles de l'anglés "Available-To-Promise") derivades d'ell, no és adequat. En canvi, tant el MPS com l'ATP han de manejar-se en termes de sublots homogenis. Atés que la quantitat exacta de producte homogeni dels lots previstos en el MPS no se sap exactament fins que s'han realitzat les activitats de classificació, l'ATP també hereta aquesta incertesa, portant un nou nivell de complexitat. El producte no homogeni no es pot acumular per a satisfer futures ordees entrants. Més encara, si el producte manipulat és perible, el maneig de l'homogeneïtat es torna molt més complex. Açò es deu al fet que l'estat del producte és dinàmic en el temps, i variables relacionades com qualitat, preu, etc., podrien també canviar amb el temps. Aquesta situació pot provocar costos inesperats de rebuig a banda de l'escassetat ja esmentada. El factor de perible és en si mateix un altra font d'incertesa associada a la LHP. Aquesta dissertació proposa un marc conceptual i diferents models i eines de programació matemàtica, tant en entorns deterministes com d'incertesa, per a recolzar a l'OPP i SP considerant l'efecte de LHP. L'objectiu és proporcionar un compromís fiable amb les comandes dels clients a la recerca d'un alt nivell de servei no sols en la data i la quantitat esperades, s / Grillo Espinoza, H. (2017). Advanced methods and models in uncertainty for the order promising process in supply chain characterized by the lack of homogeneity in product [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/91110 / TESIS