1,721,026 research outputs found
Practical optimisation model for SMEs of last mile delivery service
No full textThe delivery business is growing rapidly and consistently in the whole world. This is leading small and medium enterprises (SMEs) to join the business of the last mile delivery service. SMEs are different from the big players in services and products offered; thus, also the optimisation objectives of the SMEs are different from the big partners: often, SMEs do not possess vehicles and outsource to external partners the last mile deliveries, thus they aim to optimise the assignment of the deliveries for minimising the costs. Hence, the development of methods to find feasible solutions for assignation problems related to last mile delivery becomes fundamental for SMEs. This paper aims to address the problem of cost minimisation when outsourcing the last mile delivery service by mathematically representing the assignment decision problem and by proposing the genetic algorithm (GA) as metaheuristic to solve the problem. The tests revealed the effectiveness of the GA
Development of a Production Planning Support System for products with uncertain Cycle Time
No full textA proposal for estimating the order level for slow moving spare parts subject to obsolescence
No full textDuring the last decade technologies have had a significant development in many areas, as military and civil protection,
telecommunication and electrical distribution and production. Particularly in the mentioned areas we can find very
complex products, with a cycle life generally longer than their components. Companies have thus the need to better
manage the replacement of spare parts in order to reduce the holding costs and to satisfy the service level. In this paper
authors analyse the state of the art about the spare parts logistic (SPL) problem for products characterized by a long
cycle life and by slow moving spare parts subject to obsolescence. A new model to estimate the spare part order level is
then proposed and tested on a simulated case
A Modified genetic Algorithm for Time and Cost Optimization of an Additive Manufacturing Single-Machine Scheduling
No full textAdditive Manufacturing (AM) is a process of joining materials to make objects from 3D model
data, usually layer by layer, as opposed to subtractive manufacturing methodologies. Selective
Laser Melting, commercially known as Direct Metal Laser Sintering (DMLS®), is the most
diffused additive process in today’s manufacturing industry. Introduction of a DMLS® machine
in a production department has remarkable effects not only on industrial design but also on
production planning, for example, on machine scheduling. Scheduling for a traditional single
machine can employ consolidated models. Scheduling of an AM machine presents new issues
because it must consider the capability of producing different geometries, simultaneously. The
aim of this paper is to provide a mathematical model for an AM/SLM machine scheduling. The
complexity of the model is NP-HARD, so possible solutions must be found by metaheuristic
algorithms, e.g., Genetic Algorithms. Genetic Algorithms solve sequential optimization
problems by handling vectors; in the present paper, we must modify them to handle a matrix.
The effectiveness of the proposed algorithms will be tested on a test case formed by a 30 Part
Number production plan with a high variability in complexity, distinct due dates and low
production volume
Experimental analysis of the applicability of a multi-item constrained EOQ calculation algorithm
No full textThe present paper proposes the results of an experimental campaign targeted to investigate the applicability in real contexts of a new approach for the calculation of the Economic Order Quantity (EOQ) when a multitude of item have to be stored in a limited space. The approach, already presented in the literature in its basic principles, has been modified in order to make it more suitable for real needs. Subsequently, the so obtained algorithm has been tested, in simulated scenarios, with the purpose of identifying the regulation parameters with significant influence on the final results, their best values and the average level of performances the approach is able to guarantee, in terms of total cost of stock and mean saturation of the warehouse. The outcomes of this study confirm the general validity of the approach even if some more deepen investigations are still necessary before a possible implementation in a real stock management application
Cost Analysis in small wind projects
No full textIn the last years an increasing attention has been paid to distributed energy production from small wind turbines (i.e. < 200 kWp). The market, especially in Italy, has grown up very rapidly in the last years (basically not existing since 3-4 years ago, now it counts approximately 8 MWp). The main purpose of the paper is therefore to provide a reliable cost analysis reference to design, plan and control a project, which also includes a correct estimation of the financial risk incurred by both EPC contractors and investors. For the firsts, it also represents a cash flow analysis tool useful for financial planning, while for the seconds it’ s useful for financial control. Key words: resource management; costs management; small wind business
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