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Vessel.js: An open and collaborative ship design object-oriented library
Published in Pentti Kujala, Liangliang Lu, Marine Design XIII, 2018
One of the fundamental concepts from object-oriented programming is the inheritance concept. Usually in a class-based programming language, objects are instances of classes, from which they can inherit properties and functions. In JavaScript objects inherit from special objects called prototypes. JS also allows encapsulation, enclosing all the functionalities of an object within that object so that the object’s methods and properties are protected from the rest of the application, allowing particular properties and functions to be specific within the boundary of the object. These two concepts allow the build of applications with reusable code, scalable architecture, and abstracted functionalities expected in Vessel.js idea (Monteiro and Gaspar, 2016).
Robotic mobile fulfillment systems: a mathematical modelling framework for e-commerce applications
Published in International Journal of Production Research, 2021
Adrien Rimélé, Michel Gamache, Michel Gendreau, Philippe Grangier, Louis-Martin Rousseau
In class-based storage, a shelf is randomly stored within a class based on its turnover rate. Classes are distributed by increasing distances from the picking station and shelves with the highest turnovers are assigned to the closest classes. Because here a shelf contains exactly one item type, which can only be found on this shelf, the turnover rate of a shelf s corresponds to that of its item type (). Equation (10) randomly draws the storage location from a uniform distribution over the set of available locations within the class of shelf . The item contained on the shelf is , which gives the turnover rate of the shelf .
Forward-reserve storage strategies with order picking: When do they pay off?
Published in IISE Transactions, 2020
Wan Wu, René B.M. de Koster, Yugang Yu
In order to answer research question 2, we compare the response time of FR storage with ABC class-based storage. ABC class-based storage is a class-based storage strategy that divides the items into three groups. As shown in Figure 2(c), a few high-demanded items (the A class items) are stored in the region closest to the I/O point. Low-demand items, grouped in the C class, are stored in the region farthest from the I/O point. ABC class-based storage is the preferred storage strategy to compare with FR storage, because: (i) dividing items into only three turnover-frequency classes yields a near-optimal solution to minimize the expected retrieval time for class-based storage (random storage has only one class whereas in full turnover-based storage, each item has its designated class) (Yu et al., 2015); (ii) ABC class-based storage can be implemented easily and there is no need to frequently reconfigure the storage assignment.
Enhancing the order picking process through a new storage assignment strategy in forward-reserve area
Published in International Journal of Production Research, 2019
Behnam Bahrami, El-Houssaine Aghezzaf, Veronique Limère
The objectives of this research, and the simulation effort, were to introduce and describe a new storage assignment policy that is implemented in an actual logistic company. This policy has been thoroughly discussed and analysed in this paper. The performance analysis presented in this study is based on the operational parameters of the case study, i.e. the company’s environment. The above policy has been compared against conventional warehouse storage layouts via a designed simulation analysis. Additionally, further investigations on the effects of the three main factors (Number of orders, number of items in one order and number of units) on proposed method’s picking efficiency have been conducted. Examining the results, one can observe that the proposed storage assignment significantly improves warehouse performance in terms of total picking travel distances. This proposed policy demonstrates a remarkable potential to shorten order completion duration and it consequently improves customer satisfaction. This is important for logistical companies as order picking is often the warehouse’s bottleneck. Thus reducing the time it takes to pick an order impacts positively the time required to have it ready for dispatch. The policy can then be used to prioritise urgent orders that have to leave the warehouse within a limited time. However, attention should be paid to the congestion especially in free seats zone. Alternatives to take this issue into account could be to spread free seats throughout the picking area for example. To get some insights into the ratio of the free seats to the home locations, two layout configurations have been designed and analysed. The results reveal that when the ratio of free seats to home locations in the picking area increases, the performance of the system in terms of distance and order lead time improves. Finally, the performance of the proposed method has been compared with class-based storage.