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12 results on '"Derhami, Shahab"'

5. Digital Twin Design Requirements for Durable Goods Distribution in Physical Internet

Author

Campos, Miguel, Derhami, Shahab, McGinnis, Leon F., Montreuil, Benoit, and Barenji, Ali

Subjects
Logistics system design, Digital twins, Physical internet, Hub relay network
Abstract

Presented at the 8th International Physical Internet Conference (IPIC 2021) 14-16 June 2021, Virtual, Today the practice for distributing large products manufactured at few original equipment manufacturers (OEMs) consists of a dedicated Point-to-Point (PtP) logistics system, typically requiring long haul transport from the factory to the wholesale destination. A growing problem is the shortage of commercial drivers willing to be away from home for several days to move products cross-country. Hub relay network logistics systems are an alternative solution to P2P logistics systems that allow reducing drivers' away-from-home times. Operating a relay-based logistics system requires accounting for multiple interrelated operational decisions that become more complicated as the system becomes larger and encompasses more players. To deal with such complexity we propose utilizing a digital twin of the distribution and logistics system as a decision-making support tool to manage the system and make operational decisions efficiently. This paper explores the design and assessment of a hyperconnected relay network of transport hubs supporting the movement of durable goods from factory to wholesale destinations. It describes requirements and challenges in developing and implementing a digital twin for such systems.

Published
2021
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6. Estimation of potential lost sales in retail networks of high-value substitutable products.

Author

Derhami, Shahab and Montreuil, Benoit

Subjects
*TRANSSHIPMENT, *DISTRIBUTION (Probability theory), *RECREATIONAL vehicles, *DATA logging, *ACQUISITION of data
Abstract

Sales data reveal only partial information about demand due to stockout-based substitutions and lost sales. We develop a data-driven algorithm to estimate stockout-based lost sales and product demands in a distribution network of high-value substitutable products such as cars, using only past sales and inventory log data and product substitution ratios. The model considers the particular customer and retailer behaviors frequently observed in high-value product markets, such as visiting multiple stores by customers for a better match and exploiting on-demand inventory transshipments by retailers to satisfy the demand for out-of-stock products. It identifies unavailable products for which a retailer could not fulfill demand and estimates the potential lost sales and the probability distribution of product demands for the potential lost sales using sales data in retailers with similar sales profiles while considering retailers' market sizes. We validate the results of our algorithm through field data collection, simulation, and a pilot project for a case of recreational vehicles. We also show the result of implementing our model to estimate lost sales across the large retail network of a leading vehicle manufacturer. Our case study shows sales data significantly underestimate the demand for most products. [ABSTRACT FROM AUTHOR]

Published
2022
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7. Optimising space utilisation in block stacking warehouses.

Author

Derhami, Shahab, Smith, Jeffrey S., and Gue, Kevin R.

Subjects
WAREHOUSING & storage, PALLETS (Shipping, storage, etc.), MANUFACTURING industries, MATERIALS handling, SPACE (Architecture), WAREHOUSE management
Abstract

Block stacking storage is an inexpensive storage system widely used in manufacturing systems where pallets of stock keeping units (SKUs) are stored in a warehouse at the finite production rates. However, determining the optimal lane depth that maximises space utilisation under a finite production rate constraint has not been adequately addressed in the literature and is an open problem. In this research, we propose mathematical models to obtain the optimal lane depth for single and multiple SKUs where the pallet production rates are finite.Asimulation model is used to evaluate performance of the proposed models under stochastic uncertainty in the major production parameters and the demand. [ABSTRACT FROM AUTHOR]

Published
2017
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12. Designing Optimal Layouts for Block Stacking Warehouses

Author

Derhami, Shahab

Subjects
Industrial and Systems Engineering
Abstract

Storing pallets of Stock Keeping Units (SKUs) on top of one another on a warehouse floor is known as block stacking. Although this storage system can be inexpensively implemented in any open area, it is challenging in terms of space planning. Designing an optimal layout for this storage system involves determining the optimal numbers of aisles and cross-aisles, bay depths, cross-aisle types, and their locations in the layout. The storage space is wasted in this system by a combination of honeycombing and accessibility aisles. Honeycombing refers to unoccupied pallet positions in a partially occupied lane that are only available to the SKU that has occupied the first pallet position of the lane. The accessibility waste refers to the space devoted to aisles and cross-aisles because they are not used for pallet storage. There is a trade-off between honeycombing and accessibility waste with respect to lane depths. Shallow lanes generate less honeycombing waste but impose more aisles to the layout, whereas the opposite is true for deep lanes. Cross-aisles improve transportation costs within the warehouse, but their devoted space contributes to the wasted space. Hence, both space utilization and transportation costs must be considered to study cross-aisles. This dissertation explores the above trade-offs and relations from three different perspectives: (1) it proposes a closed-form solution model to obtain optimal lane depths for block stacking in diverse manufacturing and non-manufacturing environments; (2) it studies the layout design problem from space utilization perspective, and proposes an optimal model to find space-efficient layouts; and, (3) it investigates the effects of cross-aisles on transportation costs and proposes a multi-objective model to design layouts that optimize both space utilization and transportation costs. The proposed models along with the highlighted future extensions provide proper tools to the companies to design efficient warehouses and implement a comprehensive foundation for further research.

Published
2017

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