317 research outputs found

    İkame ürün dağıtım ağlarında stok optimizasyonu ve optimal dağıtım politikaları

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    06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Çok ürünlü stok sistemlerinde ürün stoklarının eşgüdümlü olarak yenilenmesi, özellikle ulaştırma maliyetlerinde oluşan ölçek ekonomileri nedeniyle önemli maliyet kazançları sağlar. Bunun yanı sıra bu tür stok sistemlerinde ürün ikamesi yapılabilmesi, stok maliyetlerini önemli derecede düşürür. Tezde, ürünlerin birbirileri ile ikame edilebildiği çok ürünlü stok sistemlerinde ürün kombinasyonu dağıtım ve stokastik stok yenileme problemi incelenmiştir. Ele alınan problemde ürün stokları eşgüdümlü olarak yenilenmekte ve müşteri talebi firma kaynaklı olarak stoklardaki ürünlerin herhangi bir kombinasyonuyla karşılanabilmektedir. Amaç, sonsuz zaman ufkunda birim zaman başına ortalama maliyeti yaklaşık olarak en küçükleyen ürün kombinasyonu dağıtım ve stok yenileme politikasının belirlenmesidir. Tezde, stok yenileme politikası olarak sürekli gözden geçirme esasına dayanan eşgüdümlü (S,c,s) “can order” politikası kullanılmış ve stok kontrol parametrelerinin belirlenmesinde literatürdeki çalışmalardan faydalanılmıştır. Ürün kombinasyonu dağıtım problemi ise yarı Markov karar süreci olarak modellenmiş ve çözüm için Q faktör fonksiyonunun çok katmanlı yapay sinir ağlarıyla tahmin edildiği ödüllü öğrenme algoritmaları kullanılmıştır. Çalışmada, ürün kombinasyonu dağıtım ve stok yenileme problemini sıralı ve yinelemeli olarak çözen bir algoritma geliştirilmiş ve değişik ölçeklerdeki uygulamalı denemelerde, geliştirilen algoritmanın performansı miyopik politikalarla kıyaslanmıştır. Gerçekleştirilen uygulamalı denemelere göre, geliştirilen algoritmayla elde edilen ürün kombinasyonu dağıtım ve stok yenileme politikalarının ortalama maliyetleri, miyopik politikaların ortalama maliyetlerinden çok daha düşüktür.In multi-product inventory systems, considerably savings in specially transportation costs may be achieved by coordination of replenishment orders for groups of products. Moreover, product substitutions in these systems reduce significantly inventory costs. In this thesis, a fully substitutable multi product system is considered in which customer demands may be satisfied by delivering any combination of products. In the studied system, product substitution is driven by firm and product inventories may be replenished by coordinated control. The aim of the thesis is to determine order fulfillment and replenishment policies minimizing approximately average cost in unit time in infinite horizon. In this thesis, a specific control system is considered which is known as a (S,c,s) type policy, and works in the literature are used to determine the control parameters. The order fulfillment problem is modeled as a semi Markov decision process, and reinforcement learning algorithms with approximation to Q factor function by artificial neural network are used to solve this problem. In the thesis, an algorithm is developed which determines iteratively order fulfillment and (S,c,s) policies for each product in a multi-product inventory system. In numerical examples, it is seen that order fulfillment and replenishment policies determined by the developed algorithm outperform myopic policies

    Optimizing Inventory for Profitability and Order Fulfillment Improvement

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    Despite the extensive research on inventory management, few studies have investigated the optimization of inventory classification and control policies for maximizing the net present value of profit and order fulfillment performance. This dissertation aims to fill the gaps, and consists of two main essays. Essay One (Chapter 1) presents a new multi-period optimization model to explicitly address nonstationary demand, arbitrary review periods, and SKU-specific lead times, with the objective of maximizing the net present value of profit. A real-world application and computational experiments show that the optimal dynamic inventory classification and control decisions obtained from the model significantly reduce both safety stock and base stock levels compared to a multi-criteria inventory classification scheme and the traditional ABC approach. Essay Two (Chapter 2) examines two order-based fulfillment performance measures: the order fill rate, defined as the percentage of orders that are completely filled from available inventory; and the average customer-order fill rate, defined as the mean percentage of total units in a customer order that can be filled from on-hand inventory. Novel optimization models are developed to maximize the order fulfillment performance. Computational results indicate that a commonly used item-based measure in general does not adequately indicate order-based performance, and the tradeoffs between profit and order-based measures vary with inventory investment. This research contributes to the existing literature by providing new approaches to optimize inventory classification and control policies with various performance criteria. It also provides practitioners with a viable way to manage inventory with nonstationary demand, general review periods and lead times, and further allows companies to quantity the tradeoffs of different performance measures

    Think Local-Act Local: Is It Time to Slow Down the Accelerated Move to Global Marketing?

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    In view of the accelerated move of great corporations towards global marketing, the strategic changes of such companies raise interesting questions. Is marketing globalization reaching its limits after years of implementation? Is it time for companies to rethink their strategies and move back, like Coca-Cola, to a multi-domestic marketing approach?Global Marketing, Multi-Domestic Marketing Approach, Brand Equity, Drawbacks of Marketing Globalization, Coca-Cola

    Innovation in Marketing Channels

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    In more recent years, the context of globalization in which market channel structures and strategies are developing is bringing to a more complex concept of marketing channels, with disintermediation or reintermediation, multichanneling and new roles/specializations that are emerging as new issues.In this context, innovation in marketing channels becomes a complex, multiorganizational, multidisciplinary activity that requires collaboration and interactions across various entities within the supply chain network. In recent years, the innovation processes in marketing channels have occurred with high intensity and speed, especially following the changes spurred by technology that allowed the adoption of more efficient organizational solutions.Retail; Channel Structure; Innovation in Marketing Channels; Retail Technological Innovation; Global Markets

    Factors Affecting Supplier Managed Inventory (SMI) Implementation

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    A major impediment to efficient supply chain integration is the cost of managing inventory. Due to the need to create efficiencies in the supply chain by targeting this “inventory” link, the concept of Supplier Managed Inventory (SMI) was born. However, most of the research has focused on the grocery industry and large companies. There is a lack of studies on the factors that affect the success of SMI programs in manufacturing industry

    Grocery omnichannel perishable inventories: performance measures and influencing factors

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    Purpose- Perishable inventory management for the grocery sector has become more challenging with extended omnichannel activities and emerging consumer expectations. This paper aims to identify and formalize key performance measures of omnichannel perishable inventory management (OCPI) and explore the influence of operational and market-related factors on these measures. Design/methodology/approach- The inductive approach of this research synthesizes three performance measures (product waste, lost sales and freshness) and four influencing factors (channel effect, demand variability, product perishability and shelf life visibility) for OCPI, through industry investigation, expert interviews and a systematic literature review. Treating OCPI as a complex adaptive system and considering its transaction costs, this paper formalizes the OCPI performance measures and their influencing factors in two statements and four propositions, which are then tested through numerical analysis with simulation. Findings- Product waste, lost sales and freshness are identified as distinctive OCPI performance measures, which are influenced by product perishability, shelf life visibility, demand variability and channel effects. The OCPI sensitivity to those influencing factors is diverse, whereas those factors are found to moderate each other's effects. Practical implications- To manage perishables more effectively, with less waste and lost sales for the business and fresher products for the consumer, omnichannel firms need to consider store and online channel requirements and strive to reduce demand variability, extend product shelf life and facilitate item-level shelf life visibility. While flexible logistics capacity and dynamic pricing can mitigate demand variability, the product shelf life extension needs modifications in product design, production, or storage conditions. OCPI executives can also increase the product shelf life visibility through advanced stock monitoring/tracking technologies (e.g. smart tags or more comprehensive barcodes), particularly for the online channel which demands fresher products. Originality/value- This paper provides a novel theoretical view on perishables in omnichannel systems. It specifies the OCPI performance, beyond typical inventory policies for cost minimization, while discussing its sensitivity to operations and market factors

    Smart Material Planning Optimization Problem Analysis

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    Mostly, the concept of smart manufacturing is addressed based upon how to effectively facilitate the production activities by using the automation equipment; however, causing the fluctuation of production may frequently root to the uncertain incoming sales orders. These uncertain factors may be influenced by various economic parameters, such as changes within trade regulations, competitor innovations, and changes within the market. In order to reduce the difference between the forecasted demand versus actual demand and to minimize risk, these factors need to be taken into account and be fully investigated. The current widely applied forecast methods are factory capacity-driven and based on the trend against the activity history. When the uncertainty comes from the external, then the forecasts derived from these models cannot provide convincing insights to let the firms make decisions confidently. Many previous prestigious studies focused on the problem-solving optimization mathematic methods and articulated the causality among latent factors; few have addressed to a holistic framework that the firms can practice on. This study presents a clear operable step-by-step framework to manage and cushion the impact from the external uncertain factors. It also introduces three novel and feasible production planning models with the consideration of the economic parameters. The empirical case was a multi-nation machinery-making firm who has adopted the proposed framework to optimize the material forecasts pursuing their smart manufacturing goals

    Application of Optimization in Production, Logistics, Inventory, Supply Chain Management and Block Chain

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    The evolution of industrial development since the 18th century is now experiencing the fourth industrial revolution. The effect of the development has propagated into almost every sector of the industry. From inventory to the circular economy, the effectiveness of technology has been fruitful for industry. The recent trends in research, with new ideas and methodologies, are included in this book. Several new ideas and business strategies are developed in the area of the supply chain management, logistics, optimization, and forecasting for the improvement of the economy of the society and the environment. The proposed technologies and ideas are either novel or help modify several other new ideas. Different real life problems with different dimensions are discussed in the book so that readers may connect with the recent issues in society and industry. The collection of the articles provides a glimpse into the new research trends in technology, business, and the environment

    Optimal scope of supply chain network & operations design

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    The increasingly complex supply chain networks and operations call for the development of decision support systems and optimization techniques that take a holistic view of supply chain issues and provide support for integrated decision-making. The economic impacts of optimized supply chain are significant and that has attracted considerable research attention since the late 1990s. This doctoral thesis focuses on developing manageable and realistic optimization models for solving four contemporary and interrelated supply chain network and operations design problems. Each requires an integrated decision-making approach for advancing supply chain effectiveness and efficiency. The first model formulates the strategic robust downsizing of a global supply chain network, which requires an integrated decision-making on resource allocation and network reconfiguration, given certain financial constraints. The second model also looks at the strategic supply chain downsizing problem but extends the first model to include product portfolio selection as a downsizing decision. The third model concerns the redesign of a warranty distribution network, which requires an integrated decision-making on strategic network redesign and tactical recovery process redesign. The fourth model simultaneously determines the operational-level decisions on job assignment and process sequence in order to improve the total throughput of a production facility unit

    An engineering approach to improving hospital supply chains

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    Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 130-132).This thesis explores supply chain management practices that have been implemented, and have improved supply chains in industries outside of healthcare. The presented supply chain practices have been selected because they have the potential to improve efficiency, reduce costs and improve patient safety within hospitals. Due to the diverse nature of hospitals and a unique product profile, there is no "one size fits all" supply chain solution that can be implemented. Therefore, product specific characteristics are discussed that can be used by hospitals in order to develop segmentation policies. Supply chain best practices from outside of the healthcare industry are presented for each category of segmented products. The culmination of this thesis is the presentation of a supply chain that will enable the hospital to significantly reduce inventory storage space, on hand inventory value, and time spent by nurses managing inventory. The proposed supply chain model is patient specific and involves the delivery of items from an offsite warehouse directly to the patient's bedside. In order to successfully implement a new supply chain solution in a hospital setting, change management is a critical part of the process. Methods are presented that have resulted in successful implementations of complex systems within hospitals. Three areas must be considered when managing change in this type of setting, the healthcare environment, the hospital's internal management and operational aspects of the hospital supply chain. Using simulation models, we show that implementation of the proposed supply chain for appropriately segmented products will result in significant supply chain cost savings and boost the revenue.by Scott Hsiang-Jen Cheng and Graham J. Whittemore.M.Eng.in Logistic
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