scholarly journals An Integrated Multiechelon Logistics Model with Uncertain Delivery Lead Time and Quality Unreliability

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Ming-Feng Yang ◽  
Yi Lin ◽  
Li Hsing Ho ◽  
Wei Feng Kao
Keyword(s):  
Customer Service ◽  
Lead Time ◽  
Ant Colony Algorithm ◽  
Service Level ◽  
Decision Makers ◽  
Just In Time ◽  
Production Run ◽  
Proposed Model ◽  
Customer Service Level ◽  
Critical Practices

Nowadays, in order to achieve advantages in supply chain management, how to keep inventory in adequate level and how to enhance customer service level are two critical practices for decision makers. Generally, uncertain lead time and defective products have much to do with inventory and service level. Therefore, this study mainly aims at developing a multiechelon integrated just-in-time inventory model with uncertain lead time and imperfect quality to enhance the benefits of the logistics model. In addition, the Ant Colony Algorithm (ACA) is established to determine the optimal solutions. Moreover, based on our proposed model and analysis, the ACA is more efficient than Particle Swarm Optimization (PSO) and Lingo in SMEIJI model. An example is provided in this study to illustrate how production run and defective rate have an effect on system costs. Finally, the results of our research could provide some managerial insights which support decision makers in real-world operations.

Investigating the value of reducing errors in inventory information from a supply chain perspective

Kybernetes ◽  
2015 ◽  
Vol 44 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Kazim Sari
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Lead Time ◽  
Service Level ◽  
Supply Chain Collaboration ◽  
Content Type ◽  
Useful Knowledge ◽  
Lead Time Reduction ◽  
Customer Service Level ◽  
Time Reduction

Purpose – The purpose of this paper is to investigate the value of reducing errors in inventory information from a supply chain perspective. To this end, the benefits of reducing errors in inventory information are compared with those of lead time reduction and supply chain collaboration. Design/methodology/approach – A simulation model is constructed to perform the analysis. Findings – Results show that lead time reduction is the most important strategy for a supply chain in reducing total supply chain cost. In terms of customer service level, on the other hand, strategy of reducing errors in inventory information is observed as the most considerable strategy. However, the results for supply chain collaboration are somewhat unexpected. Namely, in spite of its popularity, supply chain collaboration provides very limited contribution to the supply chain. Practical implications – This research provides useful knowledge for the managers of a business enterprise in prioritizing various supply chain strategies. Originality/value – In supply chain management literature, greater emphasis is given to lead time reduction and supply chain collaboration than dealing with errors in inventory information. This research makes it clear that errors in inventory information should not be underestimated.

scholarly journals Leagile supply chain network design through a dynamic two-phase optimization in view of Order Penetration Point

2020 ◽  
Author(s):  
Masoud Rabbani ◽  
Soroush Aghamohamadi Bosjin ◽  
Neda Manavizadeh
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Agile Manufacturing ◽  
Service Level ◽  
Second Phase ◽  
Supply Chain Network ◽  
Industrial Case Study ◽  
Total Cost ◽  
Proposed Model ◽  
Customer Service Level

In the contemporary world, combining the concept of agile and lean manufacturing (LM) is one of the most strategic and appealing concerns in the industrial environments. In this paper, a new Leagile structure is proposed for a supply chain. This research covers long term and mid-term horizon by designing a supply chain network up to the order penetration point (OPP) and final assembly and sale planning respectively. The problem is programmed in two phases. First, a bi-objective optimization is developed to minimize the total cost related with LM. In the second phase, the total cost and the customer service level (CSL) are considered as the agile manufacturing (AM) architecture. In the proposed model, a utility function is applied to set balance between the price and customer satisfaction. In addition, a robust credibility-based fuzzy programming (RCFP) is developed to handle uncertainty of the first phase. The proposed model and the solution method are implemented for a real industrial case study to show the applicability and usefulness of this study. According to the results, improving the customer service level can enhance the total cost of the second phase meaning that customer responsiveness price is too high for the proposed system.

scholarly journals ANALISIS MASALAH TRANSHIPMENT MENGGUNAKAN SOFTWARE LINGO DI PT.SBT

2020 ◽  
Vol 6 (2) ◽  
pp. 94-99
Author(s):  
Niken Septiani Kurnia
Keyword(s):  
Customer Service ◽  
Lead Time ◽  
Service Level ◽  
Customer Service Level

Pengaplikasian model transhipment pada transportasi seringkali dijumpai dalam dunia bisnis, entah untuk konsolidasi ataupun membagi produk menjadi beberapa bagian sampai akhirnya dikirim ke tujuan. Kondisi seperti ini terkadang membuat perusahaan mengeluarkan biaya yang cukup besar untuk transportasi serta lead time produk sampai ke konsumen yang lebih panjang sehingga mempengaruhi customer service level, padahal sejatinya perusahaan menginginkan customer service level yang baik serta keuntungan yang maksimum dengan biaya yang minimum. PT. SBT yang merupakan perusahaan yang bergerak dalam bidang pendistribusian barang bangunan ini juga tidak terlepas dari kegiatan transportasi yang menerapkan sistem transhipment dengan kepemilikan 3 gudang sebagai tempat transit, dimana ketiga gudang ini memiliki lokasi yang berbeda-beda sehingga perlu dilakukan penelitian lebih lanjut apakah dengan adanya ketiga gudang tersebut biaya transportasi yang dikeluarkan sudah optimal atau belum. Penelitian dilakukan menggunakan data sekunder dari penelitian terdahulu dengan tujuan membandingkan hasil metode yang digunakan penelitian terdahulu dengan hasil penelitian ini, sehingga dapat memberikan masukan terbaik bagi perusahaan dalam aspek transportasi guna mencapai tujuan perusahaan. Pendekatan yang digunakan dalam menyelesaikan masalah transhipment ini yaitu menggunakan software Lingo yang tentunya dengan harapan memberikan hasil optimal. Hasil penelitian menunjukkan adanya penurunan total biaya transportasi yang awalnya Rp 3.275.000 menjadi Rp 1.413.000 dengan selisih biaya sebesar Rp 1.862.000 atau sebesar 56,85%.

Modeling of an Inventory System with Variable Demands and Lead Times using a Fuzzy Approach

2016 ◽  
pp. 133-151
Author(s):  
Vijay Kumar ◽  
Pravin Kumar
Keyword(s):  
Customer Service ◽  
Lead Time ◽  
Service Level ◽  
Research Topic ◽  
Lead Times ◽  
Inventory Cost ◽  
Safety Stock ◽  
Customer Service Level ◽  
Optimum Order ◽  
Total Inventory

Inventory modeling has always been an innovative research topic for the researchers. It is concerned with minimization of the total inventory cost and maximization of the service level with minimum inventory. In the real world, the demand is always variable; and also the lead time of supply of an item cannot be always fixed due to some unavoidable circumstances. This chapter is focused on an inventory model with shortages where demand quantity and lead time are considered as variable and represented by triangular fuzzy numbers. An expression for optimum order size, reorder point, safety stock and fuzzy total safety stock cost is developed for a fixed customer service level. This model may help the manager to minimize the inventory cost with a maximum service level under the environment of uncertainty and vague information.

scholarly journals Service-oriented performance of inventory models with partial information on unimodal demand lead-time distributions

2020 ◽  
Author(s):  
Gerrit K. Janssens ◽  
Lotte Verdonck ◽  
Katrien Ramaekers
Keyword(s):  
Customer Service ◽  
Lead Time ◽  
Partial Information ◽  
Service Level ◽  
Inventory Level ◽  
Worst Case ◽  
Point Distribution ◽  
Safety Stock ◽  
Demand Distribution ◽  
Customer Service Level

Facing uncertainty in demand, companies try to avoid stock-outs by holding safety inventories, depending on a pre-set customer service level. The knowledge of the demand distribution during lead-time serves to determine the safety inventory level. Many times the distribution is not fully known, except maybe for its range, mean or variance. However literature shows that the performance of holding safety stock strongly depends on the characteristics of the distribution. One option is to protect against the worst case distribution given some information like range or moments. But this worst case is a two-point distribution, bringing unbelief to managers that such an occurrence would ever appear. Mostly they share the opinion that the demand distribution is unimodal. This research develops a technique to derive the safety stock for unimodal demand distributions of which the mode either is known or can be estimated. In this way, the managers obtain solutions to the decision problem including a higher belief that the related type of distribution might appear in practice.

What should be lean buffer threshold for the forward-reserve warehouse?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bhavin Shah
Keyword(s):  
Mathematical Model ◽  
Customer Service ◽  
Value Added ◽  
Service Level ◽  
Buffer Size ◽  
Value Stream Mapping ◽  
Content Type ◽  
Customer Service Level ◽  
The Impact ◽  
Just Right

PurposeThe assorted piece-wise retail orders in a cosmetics warehouse are fulfilled through a separate fast-picking area called Forward Buffer (FB). This study determines “just-right” size of FB to ensure desired Customer Service Level (CSL) at least storage wastages. It also investigates the impact of FB capacity and demand variations on FB leanness.Design/methodology/approachA Value Stream Mapping (VSM) tool is applied to analyse the warehouse activities and mathematical model is implemented in MATLAB to quantify the leanness at desired CSL. A comprehensive framework is developed to determine lean FB buffer size for a Retail Distribution Centre (RDC) of a cosmetics industry.FindingsThe CSL increases monotonically; however, the results concerning spent efforts towards CSL improvement gets diminished with raised demand variances. The desired CSL can be achieved at least FB capacity and fewer Storage Waste (SW) as it shifts towards more lean system regime. It is not possible to improve Value Added (VA) time beyond certain constraints and therefore, it is recommended to reduce Non-Value Added (NVA) order processing activities to improve leanness.Research limitations/implicationsThis study determines “just-right” capacity and investigates the impact of buffer and demand variations on leanness. It helps managers to analyse warehouse processes and design customized distribution policies in food, beverage and retail grocery warehouse.Practical implicationsProposed buffering model offers customized strategies beyond pre-set CSL by varying it dynamically to reduce wastages. The mathematical model deriving lean sizing and mitigation guidelines are constructive development for managers.Originality/valueThis research provides an inventive approach of VSM model and Mathematical algorithm endorsing lean thinking to design effective buffering policies in a forward warehouse.

scholarly journals A literature review on multi-echelon inventory management: the case of pharmaceutical supply chain

2018 ◽  
Vol 200 ◽  
pp. 00013 ◽  
Author(s):  
Nouçaiba Sbai ◽  
Abdelaziz Berrado
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Inventory Management ◽  
Raw Materials ◽  
Integrated Approach ◽  
Service Level ◽  
Pharmaceutical Products ◽  
Management Problem ◽  
Pharmaceutical Supply Chain ◽  
Customer Service Level

Inventory management remains a key challenge in supply chain management. Many companies recognize the benefits of a good inventory management system. An effective inventory management helps reaching a high customer service level while dealing with demand variability. In a complex supply chain network where inventories are found across the entire system as raw materials or finished products, the need for an integrated approach for managing inventory had become crucial. Modelling the system as a multi-echelon inventory system allows to consider all the factors related to inventory optimization. On the other hand, the high criticality of the pharmaceutical products makes the need for a sophisticated supply chain inventory management essential. The implementation of the multi-echelon inventory management in such supply chains helps keeping the stock of pharmaceutical products available at the different installations. This paper provides an insight into the multi-echelon inventory management problem, especially in the pharmaceutical supply chain. A classification of several multi-echelon inventory systems according to a set of criteria is provided. A synthesis of multiple multi-echelon pharmaceutical supply chain problems is elaborated.

scholarly journals Multi-objective optimization model of waste tire recycling network

2020 ◽  
Vol 214 ◽  
pp. 03052
Author(s):  
Bin Wang ◽  
HeHua Li
Keyword(s):  
Environmental Protection ◽  
Customer Service ◽  
Service Level ◽  
Decision Variable ◽  
Multi Objective ◽  
Waste Tire ◽  
Multi Objective Programming ◽  
Customer Service Level ◽  
Logistics Enterprises ◽  
Waste Tire Recycling

To achieve sustainable development, logistics enterprises need not only to reduce costs, but also to save energy for environmental protection and improve customer service level. The improvement of reverse logistics management level of waste tires is of great significance to improve the efficiency of the automobile industry. In this paper, multi-objective programming is adopted to establish the waste tire recycling network model. The decision variable is whether the network nodes are set or not, the traffic flow between nodes. Constraints include meeting customer demand, balance of flow in and out of logistics nodes, etc. The model is solved by ε- constraint. Taking the actual data of the enterprise as an example, the operation results show that the operation cost, carbon emission and customer transportation distance can get an consistence within a certain range. Waste tire logistics enterprises can realize the simultaneous improvement of profit, environmental protection and customer service level.

Comparative multi criteria analysis and dependent optimisation through integrated supply chain

2014 ◽  
Vol 63 (8) ◽  
pp. 1046-1069 ◽  
Author(s):  
Sanjay Sharma ◽  
Akshat Sisodia
Keyword(s):  
Supply Chain ◽  
Lead Time ◽  
Service Level ◽  
Inventory Level ◽  
Inventory Policies ◽  
Inventory Cost ◽  
Content Type ◽  
Customer Service Level ◽  
Integrated Supply Chain ◽  
Different Levels

Purpose – The purpose of this paper is to compare various inventory policies and their effect on various performance metrics at different levels of a multi stage supply chain. Later the model is integrated to include optimization of entire supply chain through implementation of collaborative supply chain model. Design/methodology/approach – Alternative inventory policies have been developed at different echelons and a comparison reflecting the usability on various factors such as inventory level, inventory cost and service level is presented so as to support the decision-making process. Various inventory policies such as economic order quantity, periodic ordering (T, M) and stock to demand have been considered. Along with the basic assumptions; lead time, demand variability, variability in demand during lead time, stock out costs have also been included to make the model more applicable to practical situations. Findings – After the selection of most appropriate inventory policy at each level through a decision matrix, the total cost of operating such a supply chain is calculated along with other parameters such as service level and inventory turns. The approach is of aggregating the optimized value at each echelon referred to as aggregated supply chain in the paper. Then the concept of integrated supply chain is introduced which optimizes the supply chain as a whole, rather than aggregating local optima. The comparison is made between the two approaches that prove the integrated supply chain's superiority. Furthermore, dependent optimization is run as it is not practically possible for each echelon to optimize at the same time. Originality/value – Each echelon is allowed to optimize at a time and other echelons assume corresponding values. This final comparative multi criterion analysis is based on the three factors, i.e. inventory cost, customer service level and inventory turnover with different weights assigned to each factor at different levels of a supply chain. Finally a consolidation of results is made to reflect the overall preference which proves that an integrated supply chain best serves all the parameters combined together.

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