1,720,981 research outputs found
New project financing and eco-efficiency models for investment sustainability
Full text linkIn the paper, we introduce the Special Issue entitled “New Project Financing and EcoEfficiency Models for Investment Sustainability”, and later present the form and contents of the thematic issue
Reti distributive multilivello. Ottimizzare più che si può
No full textOggi molte aziende si trovano di fronte al problema cruciale di decidere simultaneamente dove ubicare nuovi impianti produttivi e distributivi e come servire i propri clienti. Il presente studio propone una famiglia di modelli di programmazione lineare di tipo cost-based capaci di supportare l’ottimizzazione di una rete logistica operante nel mercato mondiale. I modelli proposti sono stati applicati offrendo notevoli risparmi di costo nella logistica in Arcotronics S.p.A, azienda bolognese leader nella produzione di componenti elettronici e di macchine automatiche
A methodology for estimating the operating costs of production lines
No full textThe paper proposes a methodology for the cost assessment of production lines with unreliable machines and finite buffers. This methodology is based on the new concept of "Line Equipment Cost" (LEC), that is the actual operating cost of a certain machine which is used into a certain line configuration. For each machine, this kind of cost not only depends on a set of static parameters describing the statistical and structural properties of the machine, but also on its actual performance which, in turn, strictly depends on the specific line configuration where the machine is installed. If the line configuration is modified (e.g., more/less buffer space is available) the machine's performance is expected to improve/degrade so that its LEC value, which dynamically expresses the machine's actual operating cost, must be properly adjusted. Hence, in order to evaluate any production line, first the specific LEC values of the single machines in that line should be computed, then the "Total Line Cost" (TLC) can be determined by summing up those LEC values. Finally, the paper provides some numerical results in order to show the applicability of the proposed methodology which can be used not only to evaluate the actual operating cost of a specific production line (expressed by the TLC value), but also to compare different line configurations in order to drive strategic decision
A methodology for estimating the operating costs of production lines
No full textThe paper proposes a methodology for the cost assessment of production lines with unreliable machines and finite buffers. This methodology is based on the new concept of "Line Equipment Cost" (LEC), that is the actual operating cost of a certain machine which is used into a certain line configuration. For each machine, this kind of cost not only depends on a set of static parameters describing the statistical and structural properties of the machine, but also on its actual performance which, in turn, strictly depends on the specific line configuration where the machine is installed. If the line configuration is modified (e.g., more/less buffer space is available) the machine's performance is expected to improve/degrade so that its LEC value, which dynamically expresses the machine's actual operating cost, must be properly adjusted. Hence, in order to evaluate any production line, first the specific LEC values of the single machines in that line should be computed, then the "Total Line Cost" (TLC) can be determined by summing up those LEC values. Finally, the paper provides some numerical results in order to show the applicability of the proposed methodology which can be used not only to evaluate the actual operating cost of a specific production line (expressed by the TLC value), but also to compare different line configurations in order to drive strategic decision
AN INTEGRATED PRODUCTION-DISTRIBUTION MODEL FOR THE DYNAMIC LOCATION AND ALLOCATION PROBLEM WITH SAFETY STOCK OPTIMIZATION
No full textThe design and management of a multi-stage production-distribution system is one of the most critical problems in logistics and in facility management. Companies need to be able to evaluate and design different configurations for their logistic networks as quickly as possible. This means coordinating the entire supply chain effectively in order to minimize costs and simultaneously optimize facilities location, the allocation of customer demand to production/distribution centers, the inbound and outbound transportation activities, the product flows between production and/or warehousing facilities, and the reverse logistics activities, etc.
Full optimization of supply chain is achieved by integrating strategic, tactical, and operational decision making in terms of the design, management, and control of activities. The cost-based and mixed-integer programming model presented in this study has been developed to support management in making the following decisions: the number of facilities (e.g. warehousing systems, distribution centers), the choice of their locations and the assignment of customer demand to them, and also incorporate tactical decisions regarding inventory control, production rates, and service level determination in a stochastic environment. This paper presents an original model for the dynamic location allocation problem with control of customer service level and safety stock optimization. An experimental analysis identifies the most critical factors affecting the logistics cost, and to finish, an industrial application is illustrated demonstrating the effectiveness of the proposed optimization approach
An integrated approach to the design and management of a supply chain
No full textIn the modern competitive business environment the design and management of supply chains is one of the most important and critical problems facing managers of multinational companies operating worldwide. There are three levels of decisions in a supply chain: strategic, tactical, and operational levels. The literature generally treats these decisions separately.
This study defines a conceptual framework for the development of new modeling approaches to the Production Distribution Logistic System Design (PDSD) problem. In particular, the authors introduce the initial basis for the development of an innovative decision support systems platform capable of integrating the design, management, control, and optimization activities for a supply chain system
A multiple single-pass heuristic algorithm solving the stochastic assembly line rebalancing problem
No full textAssembly line rebalancing is a problem companies are frequently confronted with as continuous changes in product features and volume demand caused by the volatility of modern markets result in re-definition of assembly tasks and line cycle time fluctuations. Consequently, managers are forced to adjust the balancing of their lines in order to adapt to the new conditions while trying to minimise both increases in completion costs and costs related to changes in task assignment. In particular, when modifications are made to line balancing, costs are incurred for operator training, equipment switching and moving, and quality assurance. The stochastic assembly line rebalancing problem is essentially
composed of a multi-objective problem in which two joint objectives, total expected completion cost of the new line and similarity between the new and the existing line, must be optimised. Consequently, this paper presents a multiple single-pass heuristic algorithm developed for the purpose of finding the most complete set of dominant solutions representing the Pareto front of the problem.
The operative parameters of the heuristic are set as a result of a great deal of experimentation. Moreover, a multi-objective genetic algorithm is developed and then compared with the proposed heuristic in order to demonstrate its effectiveness. Finally, an illustrative case study is presented
An integrated approach to the design and management of a supply chain
No full textAbstract In the modern competitive business environment, the design and management of supply chains is one of the most important and critical problems facing managers of multinational companies operating worldwide. There are three levels of decisions in a supply chain: strategic, tactical, and operational levels. The literature generally treats these decisions separately. This study defines a conceptual framework for the development of new modeling approaches for the Production Distribution Logistic System Design (PDSD) problem. In particular, the authors introduce the initial basis for the development of an innovative decision support systems platform capable of integrating the design, management, control, and optimization activities for a supply chain system
Multi-period location allocation problem with safety stock optimization
No full textThe design and management of a multi-stage production/distribution system is one of the most critical problem in logistics and in facility management. This manuscript deals with the so called facility location-allocation problem, i.e. with the simultaneous decisions regarding the design, management, and control of a distribution network. In particular the logistic problem object of this study deals with the determination of the number of facilities (e.g. production plants, warehousing systems, distribution centers, etc.), the choice of their locations and the assignment of customers demand to them, incorporating also tactical decisions regarding inventory control, production rates and service level determination.
The purpose is to design, test, and compare innovative cost-based models and solutions for the dynamic (i.e. multi-period) location allocation problem (LAP) with safety stock levels determination and customer service level optimization. An experimental analysis conducted on an industrial application is presented and discussed
A multiple single-pass heuristic algorithm solving the stochastic assembly line rebalancing problem
No full textAssembly line rebalancing is a problem companies are frequently confronted with as continuous changes in product features and volume demand caused by the volatility of modern markets result in re-definition of assembly tasks and line cycle time fluctuations. Consequently, managers are forced to adjust the balancing of their lines in order to adapt to the new conditions while trying to minimise both increases in completion costs and costs related to changes in task assignment. In particular, when modifications are made to line balancing, costs are incurred for operator training, equipment switching and moving, and quality assurance. The stochastic assembly line rebalancing problem is essentially composed of a multi-objective problem in which two joint objectives, total expected completion cost of the new line and similarity between the new and the existing line, must be optimised. Consequently, this paper presents a multiple single-pass heuristic algorithm developed for the purpose of finding the most complete set of dominant solutions representing the Pareto front of the problem. The operative parameters of the heuristic are set as a result of a great deal of experimentation. Moreover, a multi-objective genetic algorithm is developed and then compared with the proposed heuristic in order to demonstrate its effectiveness. Finally, an illustrative case study is presented
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