Multi objective fuzzy inventory model with deterioration, price and time dependent demand and time dependent holding cost

In this paper, we have formulated an inventory model with time dependent holding cost, selling price as well as time dependent demand. Multi-item inventory model has been considered under limitation on storage space. Due to uncertainty all the require cost parameters are taken as generalized trapezoidal fuzzy number. Our proposed multi-objective inventory model has been solved by using fuzzy programming techniques which are FNLP, FAGP, WFNLP and WFAGP methods. A numerical example is provided to demonstrate the application of the model. Finally to illustrate the model and sensitivity analysis and graphical representation have been shown.

Economic order quantity and storage assignment policies

The basic Harris’s lot size model dates back to 1913 (Harris, 1913), hence one century from its publication has been recently celebrated. Starting from the seminal work of Harris, a wide plethora of contributors has faced with the lot-sizing problem for fitting the basic model of the economic order quantity to several environments. In fact, the three key parameters constituting the basic model, i.e. the demand rate, the ordering costs, and the inventory holding costs, have been widely explored in order to relax the assumptions of the original model. However, to the best of the authors’ knowledge, the liaison between holding costs and warehouse management has not been completely addressed. The holding costs have been early considered for simplicity as primarily given by the cost of capital, and thus dependent solely on the average inventory on stock. Conversely, by including a more detailed supply chain costs contribution, the economic order quantity calculus appears depending on a recursive calculus process and on the storage assignment policy. In fact, different approaches of warehouse management, e.g. shared and dedicated storage, lead to highly variable distances to be covered for performing the missions. This leads to a total cost function, and consequently to optimum lot sizes, that are affected by the warehouse management. In this paper, this relationship has been made explicit in order to evaluate an optimal order quantity taking into account storage assignment policies

A MULTI-ITEM INVENTORY MODEL WITH VARIOUS DEMAND FUNCTIONS CONSIDERING DETERIORATION AND PARTIAL BACKLOGGING

Inventory management is an important thing to be considered in order to run the activities of a company smoothly. By considering deterioration factor, partial backlogging policy and different type of demand functions, we develop a mathematical model for multi-item inventory system. In this paper, three inventory models with constant deterioration, partial backlogging, with various demand functions are developed.  We consider inventory-dependent demand, time-dependent demand and exponential demand function in each model.  In addition, we also consider the replenishment policies for those three items, viz. individual replenishment, joint replenishment and combination both individual and joint replenishments. Sensitivity analysis of the models is also performed, and we found that the ordering cost greatly affects the total inventory cost when comparing the available replenishment policies

ANALYSIS OF INVENTORY MODEL WITH PRICE DEPENDENT DEMAND INCLUDING CONSTANT DETERIORATION RATE WITH SALVAGE VALUE, HOLDING COST IS TIME-DEPENDENT AND SHORTAGE IS PARTIALLY BACKLOGGED

In this study, we examine a model of inventory for things that are deteriorating along with the price dependent demand. The deterioration rate is constant and Salvage value is related to goods that are deteriorating, and holding cost is time-dependent. The suggested approach allows for some backlog in the shortage. Based on the length of time it will be before the next replenishment, the backlog rate is determined. This framework is solved to reduce the overall cost of given inventory to showing some numerical examples with sensitivity analysis to find the optimal solution for various parameters

Two warehouse inventory policy with price dependent demand and deterioration under partial backlogging

In today's era of higher competition in the business, there are many conditions such as offered concession in bulk purchasing, seasonality, higher ordering cost, etc., which force a retailer to purchase more quantities than needed or exceed the storage capacity. So in this situation the retailer has to purchase an extra warehouse named as rented warehouse to stock the extra quantity. In this paper an inventory model for deteriorating products with selling price dependent rate is developed. The occurring shortages are assumed to be partially backlogged and cycle time is also variable. The purpose of the development of this model is to compute the amount and time of order which can optimize the total average cost of the system. A solution procedure and numerical example are presented to illustrate the implementation of the proposed study. Sensitivity analysis concerning with distinct system parameters is also presented to demonstrate the model

Mối quan hệ giữa lợi nhuận tối ưu, lượng đặt hàng tối ưu và giá mua lại trong chuỗi cung ứng xem xét mức lo ngại hao hụt: Trường hợp chuỗi cung ứng tôm sú ở tỉnh Cà Mau

Nghiên cứu thực hiện việc xây dựng các hàm số toán học và kiểm định mối quan hệ giữa kỳ vọng lợi nhuận tối ưu, lượng đặt hàng tối ưu và giá mua lại trong chuỗi cung ứng tôm gồm hai cấp độ, xem xét đến yếu tố lo ngại sự hao hụt. Nghiên cứu sử dụng mô hình toán học để xây dựng hàm số và xử lý số liệu qua phần mềm Matlab. Các số liệu ở cả hai dạng sơ cấp và thứ cấp được thu thập từ Công ty Minh Phú và các thành tố trong chuỗi cung ứng tôm sú tại tỉnh Cà Mau. Nghiên cứu đã tìm thấy có sự khác biệt giữa lợi nhuận kỳ vọng của chuỗi cung ứng tập trung và chuỗi cung ứng phân cấp trong việc tối ưu hóa lợi nhuận của các nhân tố tham gia của hai chuỗi cung ứng này. Kết quả còn cho thấy rằng nhu cầu bất định và các mức lo ngại rủi ro khác nhau sẽ tác động trực tiếp đến các thay đổi quyết định về tồn kho của các thành phần trong chuỗi cung ứng tôm

Projeto de implementação e melhoria da gestão de stocks numa empresa agroindustrial

Mestrado em Gestão e Estratégia IndustrialAtualmente, a globalização está mais estabelecida do que nunca e com isso observa-se elevado níveis de concorrência entre empresas. Mercados dinâmicos, promovem uma maior competição, exigem padrões cada vez mais elevados de eficiência e qualidade, e tal obriga a otimização da cadeia de abastecimento. Com vista aos resultados, as empresas carecem de maximizar a sua cadeia de valor, com as cadeias de abastecimento e logística desempenhando papéis cruciais. O presente estudo aborda a importância de processos logísticos avançados e modelos de gestão de stocks, enquanto ilustra a sua aplicação numa empresa real, agroindustrial que atua no setor de FMCG (Fast Moving Consumer Goods). Através da análise das suas principais restrições logísticas, foi identificada a gestão de packing materials como a principal limitação para manter os custos baixos. Assim, neste projeto para realização da otimização de gestão de stocks, definiu-se que a procura anual foi igual às vendas de 2016, acrescendo 10%, de desperdício do processo produtivo. Consecutivamente, aplicou-se uma classificação ABC aos valores da procura anual com o objectivo de identificar os itens com maior impacto. Através do modelo de Quantidade Económica de Encomenda (QEE), determinaram-se as quantidades ótimas para um custo total de inventário mínimo, dos artigos definidos como muito importantes. Finalmente, efectuou-se os cálculos do custo total com inventários em 2016 e quais seriam os custos utilizando a QEE, e foi observado que a utilização de um método de gestão de stocks permite à empresa uma poupança anual de cerca de 15,22% face aos custos totais reportados anteriormente.Today, globalization is more established than ever before and with this we see high levels of competition between companies. Dynamic markets, which fosters competition, demands higher levels of efficiency and quality, for that is required true expertise in supply chain optimization. Deliver a good product or service that consumers' want is not enough to be competitive and sustainable in the long term in this hostile market. Looking for results, companies need to maximize their value chain, with supply chain and logistics playing really important roles. Therefore, the present study addresses the importance of advanced logistics processes and stock management models, while it illustrates its application in a real company, an agroindustrial company operating in FMCG sector. Through the analysis of its main logistic constraints, it was identified the management of packing materials as one limitation to maintain costs low. Hence, in this project for the optimization of stock management, it was defined that the annual demand for packaging materials was equal to the sales of 2016, adding 10% of the average waste process. Thus, ABC classification in order to identify the items with the highest impact. Through the Economic Order Quantity (EOQ) model it was determined the optimal for a minimal cost of, of the articles defined as very important. Finally, we calculated the total cost with inventories in 2016 and what costs would be using the EOQ, we observed that the use of a OEQ method allows the company an annual saving of 15,22% over total costs reported before.info:eu-repo/semantics/publishedVersio

Análise e otimização de stocks numa empresa do setor grossista

Mestrado Bolonha em Gestão e Estratégia IndustrialUma boa gestão de stocks tem um papel determinante para as operações de qualquer negócio de forma a otimizar os custos associados. Neste trabalho é estudada e aplicada a gestão otimizada dos stocks na empresa XPTO com o propósito de se manter a qualidade do serviço a um menor custo. Para isso, quantificou-se os custos totais sem otimização de stocks associados à gestão de stocks da empresa e os custos totais com otimização de stocks resultantes da aplicação do modelo da Quantidade Económica de Encomenda e do método de reaprovisionamento re-order point e posteriormente confrontou- se os mesmos de maneira a se perceber o impacte do modelo académico de gestão de stocks. Com este propósito, em primeiro lugar, identificou-se quais os artigos que justificam uma otimização do seu processo de gestão a partir de uma análise ABC, isto é, quais os artigos que representam o maior valor financeiro para a empresa e, assim, que com uma gestão mais otimizada refletem uma maior poupança anual. Posteriormente, com os resultados obtidos pela aplicação do modelo QEE, ficou demonstrado que seria possível diminuir os custos totais anuais em 9,19%, relativamente aos custos incorridos pela empresa no mesmo espaço temporal.A good stock management has a decisive role for the operations of any business in order to optimize the associated costs. In this work, the optimised stock management is studied and applied in the XPTO company with the purpose of maintaining the service quality at a lower cost. For this, the total costs without optimization of stock associated to the stock management of the company and the total costs with optimization of stocks resulting from the application of the Economic Order Quantity model and the re-order point replenishment method were quantified and then compared in order to understand the impact of the academic model of stock management. With this purpose, in the first place, it was identified which items justify an optimisation of their management process based on an ABC analysis, that is, which items represent the greatest financial value for the company and thus, with a more optimised management, reflect a greater annual saving. Subsequently, with the results obtained by applying the QEE model, it was shown that it would be possible to reduce total annual costs by 9.19%, relative to the costs incurred by the company in the same period of time.info:eu-repo/semantics/publishedVersio

Assessing the influence of additive manufacturing and digital inventories on an Oil & Gas company's inventory management strategy

The oil and gas (O&G) industry is increasingly considering using additive manufactured (AM) for spare part management. As O&G companies seek to align their inventory management (IM) strategies, adopting digital inventories (DI) in combination with AM has emerged as a promising solution to current IM challenges in the industry. O&G operators may leverage AM and DI to reduce physical inventories, supply chain risk, inventory-related costs and lead times. However, approaches that describe how companies may implement the DI in operations and existing IM strategies are lacking. As such, this thesis will investigate how Norwegian O&G operators may implement DI to existing IM strategies. Seven companies with experience with AM and currently participate in a DI ecosystem have been interviewed as part of the research for the thesis. The aim of the interviews was to explore the current challenges, best practices, and essential aspects for enabling the successful implementation of DIs. The interview findings are compared against relevant literature to understand the DI ecosystem comprehensively. Key challenges in the ecosystem are unsuitable procurement processes, lack of commercial models, AM spare part (SP) qualification and a lack of demand for AM projects. ERP integration and assessments of AM suitability for stored SP are discussed as key enablers of DI implementation. The benefits and challenges associated with ERP integration will be discussed, thereby providing insight towards how O&G companies may utilise existing ERP systems to maximise the value of DI. A set of frameworks for identifying SP with characteristics suitable for AM is presented. The frameworks may be used to reduce physical inventories. Two decision models visualising critical decisions and stages for a SP ordered through a DI are presented. The first decision model considers decisions and stages for a given SP ordered through a DI. The second model may be adopted by O&G operators aiming to reduce physical inventories. In conclusion, the thesis's main contribution is expanding knowledge of implementing DI as a part of IM strategies for Norwegian O&G operators. The findings highlight a need to address current procurement processes and develop attractive commercial models for all actors in the DI ecosystem. ERP integration and assessment of stored SP suitable for AM are identified as essential enablers of DI implementation