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Supply Chain Network Design Under Uncertain and Dynamic DemandRagab, Ayman Hassan 2010 December 1900 (has links)
Supply chain network design (SCND) identifies the production and distribution
resources essential to maximizing a network’s profit. Once implemented, a SCND
impacts a network’s performance for the long-term. This dissertation extends the
SCND literature both in terms of model scope and solution approach.
The SCND problem can be more realistically modeled to improve design decisions
by including: the location, capacity, and technology attributes of a resource;
the effect of the economies of scale on the cost structure; multiple products and
multiple levels of supply chain hierarchy; stochastic, dynamic, and correlated demand;
and the gradually unfolding uncertainty. The resulting multistage stochastic
mixed-integer program (MSMIP) has no known general purpose solution methodology.
Two decomposition approaches—end-of-horizon (EoH) decomposition and
nodal decomposition—are applied.
The developed EoH decomposition exploits the traditional treatment of the end-of-horizon effect. It rests on independently optimizing the SCND of every node of the
last level of the scenario-tree. Imposing these optimal configurations before optimizing
the design decisions of the remaining nodes produces a smaller and thus easier to
solve MSMIP. An optimal solution results when the discount rate is 0 percent. Otherwise,
this decomposition deduces a bound on the optimality-gap. This decomposition is neither SCND nor MSMIP specific; it pertains to any application sensitive to the
EoH-effect and to special cases of MSMIP. To demonstrate this versatility, additional
computational experiments for a two-stage mixed-integer stochastic program
(SMIP) are included.
This dissertation also presents the first application of nodal decomposition in
both SCND and MSMIP. The developed column generation heuristic optimizes the
nodal sub-problems using an iterative procedure that provides a restricted master
problem’s columns. The heuristic’s computational efficiency rests on solving
the sub-problems independently and on its novel handling of the master problem.
Conceptually, it reformulates the master problem to avoid the duality-gap. Technologically,
it provides the first application of Leontief substitution flow problems
in MSMIP and thereby shows that hypergraphs lend themselves to loosely coupled
MSMIPs. Computational results demonstrate superior performance of the heuristic
approach and also show how this heuristic still applies when the SCND problem is
modeled as a SMIP where the restricted master problem is a shortest-path problem.
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The influence of supply chain networks, flexibility and integration on the performance of small and medium enterprise in the Southern Gauteng regionOmoruyi, Osayuwamen January 2015 (has links)
D. Tech. (Business, Logistics, Faculty of Management Sciences), Vaal University of Technology / The South Africa economy has embraced the importance of small and medium enterprises (SMEs) as agents of economic growth and sustainability. However, for SMEs to be more efficient and effective towards the growth of the economy, it is important for SMEs to implement and take cognisance of the global competitive strategy among the so-called “best in class” organisations in order to also sustain and grow their business. The supply chain network with its flexibility has become the most commonly used business strategy worldwide for the improvement of performance in organisations, more especially among larger organisations. In today’s competitive environment, successful organisations are those that have been able to link their business functions within the organisation itself as well as across other businesses outside the organisation. Competitive challenges in the modern business environment have resulted in the need for organisation to integrate business processes strategically across other business units within the supply chain network.
Network perspective theory, social network theory, network management theory and relational view theory are discussed to better understand the importance of SMEs supply chain network, flexibility and integration.
The purpose of this study was to examine the influence of supply chain network, flexibility and integration on the SMEs business performance in the Southern Gauteng region. The research survey was conducted in the Meyerton, Vereeniging and Vanderbijlpark and 401 SMEs participated in the study. SPSS 22.0 was used to analyse the data and AMOS 22.0 was used to perform the confirmatory factor analysis. The structural equation modelling (SEM) was used to assess the proposed model fit and to test the statistically significant relationship of the hypothesis. The research study results revealed that supply chain network, flexibility and integration positively influence SMEs business performance. This study contributes new knowledge to the existing literature by providing a research framework that can enhance SMEs performance and also provide practical recommendations based on the research findings for SMEs and for future research. Furthermore, as one of the first studies addressing the influence of supply chain network, flexibility and integration on the performance of SMEs in the southern Gauteng region it has generated new insights and information as well as outlined the strategic reasons for SME owners and managers to improve on their business relationships. / VUT
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Reverse Logistics for Lithium-ion Batteries : A study on BPEVs in SwedenTadaros, Marduch January 2019 (has links)
In recent years the amount of newly registered electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles has increased rapidly in the Swedish market. These vehicles could be classified as battery-powered electric vehicles, and a majority carry a lithium-ion battery. The demand for lithium is expected to increase considerably, as a result of such a swift growth in battery-powered electric vehicles. Thus, if the recycling rate of lithium stays at a low level, demand could reach a scarcity-level by 2050. While neither any infrastructure nor an established process for recycling lithium-ion batteries currently exists in Sweden, this study aims to provide necessary input and verified tools for the design of a future reverse supply chain for discarded lithium-ion batteries in Sweden. The literature review of this study covers the subjects of reverse logistics, supply chain network design, and operations research. A thorough situation analysis of the Swedish market for battery-powered electric vehicles is conducted, and the composition, function, and characteristics of lithium-ion batteries are studied. The study finds that estimations of future demand of recyclable lithium-ion batteries in Sweden could be between 206 711 and 726 974 tons accumulated, based on actual and predicted sales numbers until 2030. Even if it is obvious that there are going to be large quantities of such batteries requiring recycling in the future, and even if some established processes exist, there is no defined supply chain for the collection of those batteries. Finally, a mixed-integer programming model for the design and development of a future reverse supply chain is presented. The model, characterized as a discrete multi-period facility location/allocation model, can with minor modifications be used for problems with fluctuating demand or when the demand is assumed to slowly progress until it has reached a steady state.
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Management von Nachhaltigkeit in Supply-Chain-NetzwerkenPorzig, Nicole 06 November 2014 (has links) (PDF)
Unternehmen verfügen typischerweise über mehrstufige Zuliefer- und Abnehmerbeziehungen, deren Konfiguration sich jedoch unterschiedlich komplex gestaltet. Ein Management von Nachhaltigkeit muss diese Unterschiede verstehen, bevor passende Konzepte und Maßnahmen empfohlen werden können. Die Arbeit zeigt welche Ansätze des Nachhaltigkeitsmanagements unter welchen strukturellen Konstellationen der Supply Chain geeignet sind.
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Otimização da rede de uma cadeia de suprimentos com a utilização de uma heurística baseada em Busca TabuBraido, Gabriel Machado January 2012 (has links)
O desenho e a gestão de uma cadeia de suprimentos apresentam-se, hoje, como um dos problemas mais importantes e de difícil resolução encontrado pelos gestores. A gestão da cadeia de suprimentos é uma das áreas de maior interesse da Pesquisa Operacional aplicada, buscando determinar a melhor estratégia de produção, transporte e estoque com menor custo e tempo possíveis. Esta dissertação apresenta os resultados de um estudo que objetivou implementar e avaliar uma heurística baseada em Busca Tabu para otimização de uma rede de cadeia de suprimentos. Para tanto, foi utilizada uma modelagem single-source proposta por Farias e Borenstein (2012). O problema foi resolvido com uma adaptação do método de Lee e Kwon (2010), buscando por meio de operações de troca de centros de distribuição (CDs) e arcos encontrar a configuração de menor custo para uma rede de cadeia de suprimentos. Foram resolvidas as 22 instâncias propostas por Farias e Borenstein (2012) e os resultados comprovam que, para esses cenários, o método aplicado teve um bom desempenho computacional, obtendo resultados com uma redução de 81,03% no tempo médio de processamento; contudo, as soluções obtidas pela heurística apresentaram custos médios 4,98% superiores aos resultados ótimos. Por fim, o problema foi resolvido para outras quatro instâncias com características reais, comprovando a eficiência da heurística para problemas de grande escala, visto que todas as soluções foram obtidas em um tempo inferior a 2 minutos de processamento. / The design and supply chain management are currently one of the most important and difficult problems encountered by business managers. Supply chain management is one of the most engaging areas in applied Operations Research, which seeks to determine the best strategy regarding production, shipping and storage at the lowest cost and shortest time possible. This thesis shows the results of a research that aimed to implement and evaluate a heuristic based on Tabu Search to optimize a supply chain network. For this purpose, a single-source model proposed by Farias and Borenstein (2012) was used. The problem was solved by adapting the Lee and Kwon method (2010), exchanging distribution centers (DCs) and arcs, to find the lowest cost for a supply chain network. Twenty two instances proposed by Farias and Borenstein (2012) were resolved and the results indicate that, for these scenarios, the applied method had a good computational performance, getting results with 81.03% of reduction in the average processing time. However, there was an increase of 4.98% in the average cost of the solutions obtained through the heuristic method when compared to the optimal results. Finally, the problem was solved for four other instances with real features, proving the efficiency of the heuristic for large-scale problems, since all solutions were obtained in a time less than 2 minutes of processing.
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Otimização da rede de uma cadeia de suprimentos com a utilização de uma heurística baseada em Busca TabuBraido, Gabriel Machado January 2012 (has links)
O desenho e a gestão de uma cadeia de suprimentos apresentam-se, hoje, como um dos problemas mais importantes e de difícil resolução encontrado pelos gestores. A gestão da cadeia de suprimentos é uma das áreas de maior interesse da Pesquisa Operacional aplicada, buscando determinar a melhor estratégia de produção, transporte e estoque com menor custo e tempo possíveis. Esta dissertação apresenta os resultados de um estudo que objetivou implementar e avaliar uma heurística baseada em Busca Tabu para otimização de uma rede de cadeia de suprimentos. Para tanto, foi utilizada uma modelagem single-source proposta por Farias e Borenstein (2012). O problema foi resolvido com uma adaptação do método de Lee e Kwon (2010), buscando por meio de operações de troca de centros de distribuição (CDs) e arcos encontrar a configuração de menor custo para uma rede de cadeia de suprimentos. Foram resolvidas as 22 instâncias propostas por Farias e Borenstein (2012) e os resultados comprovam que, para esses cenários, o método aplicado teve um bom desempenho computacional, obtendo resultados com uma redução de 81,03% no tempo médio de processamento; contudo, as soluções obtidas pela heurística apresentaram custos médios 4,98% superiores aos resultados ótimos. Por fim, o problema foi resolvido para outras quatro instâncias com características reais, comprovando a eficiência da heurística para problemas de grande escala, visto que todas as soluções foram obtidas em um tempo inferior a 2 minutos de processamento. / The design and supply chain management are currently one of the most important and difficult problems encountered by business managers. Supply chain management is one of the most engaging areas in applied Operations Research, which seeks to determine the best strategy regarding production, shipping and storage at the lowest cost and shortest time possible. This thesis shows the results of a research that aimed to implement and evaluate a heuristic based on Tabu Search to optimize a supply chain network. For this purpose, a single-source model proposed by Farias and Borenstein (2012) was used. The problem was solved by adapting the Lee and Kwon method (2010), exchanging distribution centers (DCs) and arcs, to find the lowest cost for a supply chain network. Twenty two instances proposed by Farias and Borenstein (2012) were resolved and the results indicate that, for these scenarios, the applied method had a good computational performance, getting results with 81.03% of reduction in the average processing time. However, there was an increase of 4.98% in the average cost of the solutions obtained through the heuristic method when compared to the optimal results. Finally, the problem was solved for four other instances with real features, proving the efficiency of the heuristic for large-scale problems, since all solutions were obtained in a time less than 2 minutes of processing.
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Otimização da rede de uma cadeia de suprimentos com a utilização de uma heurística baseada em Busca TabuBraido, Gabriel Machado January 2012 (has links)
O desenho e a gestão de uma cadeia de suprimentos apresentam-se, hoje, como um dos problemas mais importantes e de difícil resolução encontrado pelos gestores. A gestão da cadeia de suprimentos é uma das áreas de maior interesse da Pesquisa Operacional aplicada, buscando determinar a melhor estratégia de produção, transporte e estoque com menor custo e tempo possíveis. Esta dissertação apresenta os resultados de um estudo que objetivou implementar e avaliar uma heurística baseada em Busca Tabu para otimização de uma rede de cadeia de suprimentos. Para tanto, foi utilizada uma modelagem single-source proposta por Farias e Borenstein (2012). O problema foi resolvido com uma adaptação do método de Lee e Kwon (2010), buscando por meio de operações de troca de centros de distribuição (CDs) e arcos encontrar a configuração de menor custo para uma rede de cadeia de suprimentos. Foram resolvidas as 22 instâncias propostas por Farias e Borenstein (2012) e os resultados comprovam que, para esses cenários, o método aplicado teve um bom desempenho computacional, obtendo resultados com uma redução de 81,03% no tempo médio de processamento; contudo, as soluções obtidas pela heurística apresentaram custos médios 4,98% superiores aos resultados ótimos. Por fim, o problema foi resolvido para outras quatro instâncias com características reais, comprovando a eficiência da heurística para problemas de grande escala, visto que todas as soluções foram obtidas em um tempo inferior a 2 minutos de processamento. / The design and supply chain management are currently one of the most important and difficult problems encountered by business managers. Supply chain management is one of the most engaging areas in applied Operations Research, which seeks to determine the best strategy regarding production, shipping and storage at the lowest cost and shortest time possible. This thesis shows the results of a research that aimed to implement and evaluate a heuristic based on Tabu Search to optimize a supply chain network. For this purpose, a single-source model proposed by Farias and Borenstein (2012) was used. The problem was solved by adapting the Lee and Kwon method (2010), exchanging distribution centers (DCs) and arcs, to find the lowest cost for a supply chain network. Twenty two instances proposed by Farias and Borenstein (2012) were resolved and the results indicate that, for these scenarios, the applied method had a good computational performance, getting results with 81.03% of reduction in the average processing time. However, there was an increase of 4.98% in the average cost of the solutions obtained through the heuristic method when compared to the optimal results. Finally, the problem was solved for four other instances with real features, proving the efficiency of the heuristic for large-scale problems, since all solutions were obtained in a time less than 2 minutes of processing.
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THE IMPACT OF DATA BREACH ON SUPPLIERS' PERFORMANCE: THE CASE OF TARGETTian Qi (8802305) 07 May 2020 (has links)
The author investigated the condition under which competition effect and contagion effect impact the suppliers of the firm encountering data breach. An event study was conducted to analyze the stock price of 104 suppliers of Target after the large-scale data breach in 2013. The result showed that suppliers with high dependence on Target experienced negative abnormal return on the day after Target’s announcement, while those with low dependence experienced positive abnormal return. After regressing the abnormal return on some explanatory variables, the result showed that firms with better operational performance and high information technology capability were less negatively affected. This study suggested that suppliers who relatively highly rely on one customer company are susceptible for the negative shock from that customer because of contagion effect. Furthermore, maintaining good performance and investing in information technology can help firms reduce losses from negative events happened in customer companies.
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Achieving enhanced integration of sustainability into supply chain through implementation of effective strategies in environmental, economic, and social frontsAula, Heor January 2022 (has links)
Manufacturing industries have adopted globalization as a strategy to improve the reach of their products/services, bringing them closer to the customer and utilizing the cost advantage in emerging economies, better availability of resources such as raw materials, and cheaper workforce. However, with globalization came a fair share of obstacles in effectively managing the operations of a complex supply chain network spread across the globe. Failure of manufacturing firms in controlling their operations has led to a generation of wastes such as underutilization of resources, inefficient by-product disposal systems, and increased emissions from poorly managed logistics networks. Research on understanding the environmental impact of ineffectively managed supply chain networks shows that industrial operations contribute up to 20% of global carbon dioxide emissions creating a serious impact on the environment. Realizing these adverse effects, many countries across the globe have taken steps to regulate and monitor the operations and by-products produced by manufacturing firms. Multiple countries and local governments have come together to become environmentally more responsible through encouraging sustainability initiatives. They have laid more stringent regulations to pressure the manufacturing firms to transform into more sustainable and reduce their carbon footprint. Moreover, the manufacturing firms are also experiencing pressure from local governments and private NGOs. With increasing awareness of sustainability, customers have also slowly started transforming towards sustainable products and boycotting products from firms that do not comply with sustainability standards. Consequently, manufacturing firms have realized the need to become more sustainable in order to adapt to the changing regulations and customer needs. To achieve the level of sustainability in their supply chain operations, manufacturing firms have adopted innovative strategies and made changes in their policies making sustainability one of their prime goals. To achieve the desired level of sustainability, firms need to transform their current ways by incorporating a sustainability perspective into their operations. However, integrating sustainability at the operations level is not as easy as said due to existing governance gaps which are a result of ineffective control and management in global supply chain networks. This thesis aims at identifying, understanding, and analyzing the gaps in integrating sustainability into supply chains and providing suggestions on how to fulfill these gaps. Through this research three innovative sustainability strategies which can be applied at operational, organizational, and system levels are analyzed, and conclusions are drawn on how successful implementation of these strategies would help in fulfilling the governance gaps. Further, the research also analyses the plausible effects of implementing the strategies by understanding and comparing the firm performance before and after implementation. The firm performance is measured in three categories: environmental performance, operational performance, and financial performance.
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Designing Supply Chain Network Resilience : Medicine Shortages in the Pharmaceutical IndustryBarfuß, Julia, Wagenknecht, Imke January 2021 (has links)
Background: In a globalised world and increased interconnected business environments effective resilience capabilities are pivotal for disruption mitigation. In the pharmaceutical industry this concerns the phenomenon of medicine shortages and high geographical sourcing dependencies resulting in severe consequences for healthcare providers and patients. Purpose: Analysing challenges affecting resilience in the upstream of the pharmaceutical supply chain network and root-causes of the heparin sourcing shortage. This study aims to find resilience strategies to effectively manage future heparin sourcing shortages. Method: This qualitative case study analysed the dynamic phenomenon of supply chain network resilience in a German listed healthcare company. Semi- structured interviews were conducted based on non-probability purposive sampling. The empirical findings were analysed according to the thematic analysis. Conclusion: The findings indicate that insufficient management of challenges impacting the supply chain network resilience leads to medicine shortages. Driven by the ethical obligation the pharmaceutical supply chain network particularly has to deal with external hurdles and sourcing dependencies created by complex product characteristics.
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