Giuseppe Vignali

Optimisation of storage allocation in order picking operations through a genetic algorithm

This paper explores the use of a genetic algorithm (GA) to optimise item allocation in a warehouse, with the ultimate purpose of reducing the travel time of pickers, thus streamlining order picking operations. The GA is described along with a numerical example, reflecting a fast moving consumer goods warehouse, where items are assumed to be allocated according to a class-based storage system. Starting from that configuration, and taking into account the set of orders to be fulfilled, the GA identifies a new item allocation, which significantly decreases the travel distance (by approximately 20%). This involves a corresponding decrease in the cost of picking operations, and allows the warehouse to respond quicker to the requests of customers. The GA and its numerical implementation are supported by a general purpose software, such as Microsoft Excel®, programmed under visual basic for applications; the resulting tool is thus easy to use in real scenarios.

Modeling and multi-objective optimization of closed loop supply chains

The optimization of the asset management process in a closed-loop supply chain is investigated.A simulation model, based on an adapted EOQ policy, is developed to reproduce the assets flow.A multi-objective optimization, including both cost and strategic KPIs, is carried out on the closed-loop supply chain.The optimal configuration of the asset management process is identified for each scenario simulated. This study investigates the issue of optimizing the asset management process in a real closed-loop supply chain (CLSC), consisting of a pallet provider, a manufacturer and 7 retailers. A detailed simulation model, based on an adapted economic order quantity (EOQ) policy is developed under Microsoft Excel to reproduce the reorder process of assets by the manufacturer and the corresponding flow of returnable transport items (RTIs) in the CLSC. A multi-objective optimization, including both economic and strategic key performance indicators of the system, is then carried out exploiting the commercial software ModeFRONTIER. The optimization investigates three scenarios, which refer to as many operating conditions of the manufacturer. Scenario 1 basically reproduces the current operating conditions of the manufacturer, while scenarios 2 and 3 are both hypothetical, and describe situations where the manufacturer would like to minimize the purchase of new assets and the pick-up of assets from its customers, respectively. For each scenario, the optimal configuration (i.e., the setting of the asset management process that performs best in the multi-objective optimization) is identified. Scenarios 1 and 3 are found to generate the most interesting performance of the assets management process, from both the economic and strategic perspectives. Because the present paper is grounded on a real CLSC, the results are expected to be useful to logistics and supply chain managers, to support the evaluation of the performance of CLSCs.

Reducing out of stock, shrinkage and overstock through RFID in the fresh food supply chain: Evidence from an Italian retail pilot

Abstract. The paper shows how to leverage RFID technology in fresh fast moving consumer goods(FMCG) industry, and, in particular, to optimally manage stock levels on shelves, shelves replenishment,and shrinkage prevention for fresh perishable products.We deployed a pilot project on a FMCG retail supply chain, encompassing a distribution centre andtwo stores of a major Italian retailer. About 60 products have been RFID tagged at case level. We real timetracked cases of products for 4 months, through the distribution chain all the way to the stores, where theRFID deployment made it possible to punctually monitor shelves stock levels, backroom stock levels andproduct shrinkage.We demonstrate that the out of stock (OOS) problem is just one piece of a broader picture, that is shelvesstock optimization. The higher the stock level on the shelves, the lower the need for shelf replenishment,and thus the likelihood of an OOS. However, the capital holding costs and the risk for product shrinkageincrease. The latter issue is particularly relevant for fresh perishable products. This pilot demonstrates thata retailer could reduce OOS, shrinkage and capital holding costs all together, by means of efficient RFIDdata management. Potential savings for fresh products account approx 1.7% of sale turnover.This study is the first pilot project which assesses the impact of RFID technology on the supply chainof fresh perishable products; a full roll-out of the project is being planned for the next future.Keywords: RFID, out of stock, fresh perishable fast moving consumer goods, pilot study

Improving logistics efficiency of industrial districts: a framework and case study in the food sector

Focused on food industrial districts, this paper proposes an integrated approach to increase sustainability and efficiency of logistics activities. The approach is conceived to design an integrated food district, starting from a set of independent companies, and to quantify the economic savings that could be gained from the pooled management of logistics and transportation activities. Moreover, some environmental aspects are considered in the framework, as complementary features that could justify the sustainability of the new scenario. The approach was verified through a real-case application targeting companies operating in the Italian district of tomato. Results of the application show that the pooled management of packaging procurement, warehousing and transportation activities could generate significant improvements in the district sustainability, in terms of both efficiency and resources used. Due to the lack of quantitative models for the optimisation of industrial districts, the approach developed can represent a useful addition to the literature.

A quantitative evaluation of the impact of the RFID technology on shelf availability

In this paper, we aim at analyzing and punctually quantifying the benefits of the adoption of Radio Frequency Identification (RFID) technology for a better management of shop floor operations and reduction of out of stocks (OOS). To this extent, we first selected a panel of about 100 products belonging to different consumer packaged goods categories (i.e. dry foods, fresh foods, frozen products, health and beauty care) and then we identified 30 retail stores to be monitored, including both hypermarkets and supermarkets.We audited availabilities by daily mapping the number of items on the shelves at store level. In the case an OOS occurred, a store associate promptly provided the OOS root causes, chosing among 8 possible options. By combining pieces of information related to OOS magnitude, RFID impact on each root cause and customer behaviour in response to OOS, we quantified the potential benefits which could be generated by RFID adoptions, in terms of turnover increase for the retailer as well as for the manufacturer. Results obtained indicate that RFID technologies could be sustainable from an economical point of view for both the retailer and the manufacturer, when they are exploited not only for improving accuracy or efficiency of logistics processes but also for increasing sales through OOS reduction.

The impact of RFID technologies on inventory accuracy in the apparel retailing: Evidence from the field

In this paper, we assess the level of inventory accuracy that can be reached by adopting radio frequency identification (RFID) technology for inventory count operations in the fashion retailing. Thanks to an in-field implementation, we carried out two series of RFID inventory counts and compared the resulting accuracy level with that obtained exploiting the traditional barcode (BC) technology, so as to highlight the main pros and cons of the RFID adoption. As a general conclusion, the findings from the experimental campaigns and the analyses carried out suggest that RFID inventory counts are more reliable than BC ones. Moreover, under several circumstances, RFID allows detecting out-of-stock situations that are not evident when using either the BC technology or the inventory data stored in the company’ information system. From those findings, a trend of the inventory accuracy as a function of the time required for RFID inventory counts is empirically derived. Such a trend can be exploited in practical cases to estimate the accuracy level achievable with inventory counts depending on the time dedicated to those activities.

A Survey on Packaging Materials and Technologies for Commercial Food Products

This paper presents the outcomes of a comprehensive and detailed analysis of the Italian food market, targeting the Fast Moving Consumer Goods products and aimed at defining the existing relationships between product characteristics and packaging technologies. A sample of 175 products has been examined, and the corresponding characteristics and packaging technologies were derived from an in-field investigation performed in large and small Italian retailers. Subsequent statistical analyses were first focused on providing descriptive statistics concerning the packaging materials used for food products. Then, cluster analysis was exploited to group products on the basis of the material used for the primary packaging. Discriminant analysis was also adopted to identify product characteristics that significantly contribute to the choice of packaging material. Finally, based on the clusters obtained, contingency tables were used to explore possible relationships among packaging material, packaging techniques and relevant product characteristics. Results of this study could provide useful guidelines to food manufacturers to identify the most suitable packaging technology for new food products.

Intelligent Algorithms for Warehouse Management

Warehouses are important links in the supply chain; here, products are temporarily stored and retrieved subsequently from storage locations to fulfill customer’ orders. The order picking activity is one of the most time-consuming processes of a warehouse and is estimated to contribute for more than 55 % of the total cost of warehouse operations. Accordingly, scientists, as well as logistics managers, consider order picking as one of the most promising area for productivity improvements. This chapter is intended to provide the reader with an overview of different intelligent tools applicable to the issue of picking optimization. Specifically, by this chapter, we show how different types of intelligent algorithms can be used to optimize order picking operations in a warehouse, by decreasing the travel distance (and thus time) of pickers. The set of intelligent algorithms analyzed include: genetic algorithms, artificial neural networks, simulated annealing, ant colony optimization and particles swarm optimization models. For each intelligent algorithm, we start with a brief theoretical overview. Then, based on the available literature, we show how the algorithm can be implemented for the optimization of order picking operations. The expected pros and cons of each algorithm are also discussed.

The impact of (S,s) policy on supply network performance: a simulation study

This paper builds upon the study by Bottani and Montanari (2011, pp.226-269). Here, the authors presented a simulation model to assess the performance of supply networks, and investigated economic order interval (EOI) and economic order quantity (EOQ) policies under several different operating conditions of the networks, including: the network configuration; the demand behaviour and stochasticity; the lead time stochasticity; the safety stocks coefficient. In this paper, we extend and complete the previous study by investigating the (S,s) policy, i.e., a periodic review policy with re-order points and order-up-to level. To this extent, we start by presenting a model to simulate the (S,s) policy; then, by maintaining the same simulation settings used by the authors and adding the new policy, we investigate 192 scenarios in a 3 × 26 factorial design. We present some selected outcomes from the simulation runs, primarily focused on the comparison of the three reorder policies in terms of their impact on the supply network performance. From those outcomes, we derive interesting guidelines, which allow identifying the most appropriate reorder policy to be adopted in the network as a function of its operating conditions. Findings of this study also provide supply chain managers with an overview of the performance that can be expected when the (S,s) policy is adopted in a supply network.

Life-Cycle Assessment of Food-Packaging Systems

Food packaging plays a fundamental role in today’s society because it protects food from external sources of contamination and preserves food properties during the entire assigned shelf life. Due to this fundamental role, its use is increasingly widespread including emerging or underdeveloped countries. The global amount of packaging materials manufactured and disposed of every day has led many researchers to deal with the issue of their environmental impact. Several studies have been performed starting from 1990 to the present that have been aimed at demonstrating the best type of use of and end of life for each type of food-packaging material. In recent years, some studies have also demonstrated how the extension of the food shelf life by means of improved packaging could decrease the environmental impact of an entire packaged food based mainly on the reduction of the associated food waste. Based on these premises, this chapter aims at reviewing the main articles in the field of environmental assessment of food packaging by means of a life-cycle assessment approach and showing how, during the last two decades, this issue has received increasing attention. The review was performed by analysing 172 scientific papers collected from the Scopus database using specific keywords and refining the results based on a detailed analysis of the content of each article. The results show how interest in this topic has grown consistently during the last 25 years and indicates several research lines available for further studies in this field.