francesco costantino | Università degli Studi "La Sapienza" di Roma (original) (raw)

Papers by francesco costantino

Journal of Cleaner Production, 2018

New trends in product development aim at integrating the improvement of all activities related to... more New trends in product development aim at integrating the improvement of all activities related to the products’ life-cycle, particularly when considering environmental issues. Within this context, Product-Service System (PSS) appears as a promising model, representing a win-win solution for both companies and customers. In particular, the medical devices industry is a sector where the PSS approach can assume a key role. However, despite the potential benefits deriving from the implementation of PSS
solutions, few studies on PSS consider this sector.
To accomplish this, the paper proposes a methodology based on the analysis of the market demand and customers’ needs by means of the Quality Function Deployment (QFD) method, and the simulation of life-cycle scenarios through the Screening Life Cycle Modelling (SLCM) method supported by Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) tools.
A case study performed in collaboration with a manufacturer of biomedical devices showed the benefits of the proposed methodology in the development of sustainable PSS solutions. Actually, the results demonstrate the validity of such an approach in enhancing customer satisfaction, while reducing environmental concerns and costs.

The authors deal with the topic of the final assembly scheduling realized by the use of genetic a... more The authors deal with the topic of the final assembly scheduling realized by the use of genetic algorithms (GAs). The objective of the research was to study in depth the use of GA for scheduling mixed-model assembly lines and to propose a model able to produce feasible solutions also according to the particular requirements of an important Italian motorbike company, as well as to capture the results of this change in terms of better operational performances. The "chessboard shifting" of work teams among the mixed-model assembly lines of the selected company makes the scheduling problem more complex. Therefore, a complex model for scheduling is required. We propose an application of the GAs in order to test their effectiveness to real scheduling problems. The high quality of the final assembly plans with high adherence to the delivery date, obtained in a short elaboration time, confirms that the choice was right and suggests the use of GAs in other complex manufacturing systems.

Defining means to assess safety performance and delve into their causes is one of the current and... more Defining means to assess safety performance and delve into their causes is one of the current and future challenges of the ATM sector. Following the experiences of the Aerospace Performance Factor by FAA and EUROCONTROL, this research aims to apply the Analytic Hierarchy Process (AHP) in order to build synthetic and user-friendly safety reactive indicators. Therefore, it describe the process for evolve these indicators to a proactive perspective, in order to forecast future safety performance. This concept has been possible through the development of a statistical model of safety events, combining in a Monte Carlo simulation the results emerged from the literature analysis with the analytical models of historic data interpretation. Through the analysis and combination of the safety events over time (accidents, incidents and issues) and the relative control charts, this model will pinpoint critical situations and will address the interventions of the decision makers.

The authors deal with the topic of the final assembly scheduling realized by the use of genetic a... more The authors deal with the topic of the final assembly scheduling realized by the use of genetic algorithms (GAs). The objective of the research was to study in depth the use of GA for scheduling mixed-model assembly lines and to propose a model able to produce feasible solutions also according to the particular requirements of an important Italian motorbike company, as well as to capture the results of this change in terms of better operational performances. The " chessboard shifting " of work teams among the mixed-model assembly lines of the selected company makes the scheduling problem more complex. Therefore, a complex model for scheduling is required. We propose an application of the GAs in order to test their effectiveness to real scheduling problems. The high quality of the final assembly plans with high adherence to the delivery date, obtained in a short elaboration time, confirms that the choice was right and suggests the use of GAs in other complex manufacturing systems.

The lack of coordination in supply chains can cause various inefficiencies like bullwhip effect a... more The lack of coordination in supply chains can cause various inefficiencies like bullwhip effect and inventory instability. Extensive researches quantified the value of sharing and forecasting of customer demand, considering that all the supply chain partners can have access to the same information. However, only few studies devoted to identify the value of limited collaboration or information visibility, considering their impact on the overall supply chain performances for local and global service level. This paper attempts to fill this gap by investigating the interaction of collaboration and coordination in a four-echelon supply chain under different scenarios of information sharing level. The results of the simulation study show to what extent the bullwhip effect and the inventory variance increase and amplify when a periodic review order-up-to level policy applies, noting that more benefits generate when coordination starts at downstream echelons. A factorial design confirmed the importance of information sharing and quantified its interactions with inventory control parameters, proving that a poor forecasting and definition of safety stock levels have a significant contribution to the instability across the chain. These results provide useful implications for supply chain managers on how to control and drive supply chain performances.

—Inventory control policies have been recognized as a contributory factor to the bullwhip effect ... more —Inventory control policies have been recognized as a contributory factor to the bullwhip effect and inventory instability. Previous studies have indicated that there is a trade-off between bullwhip effect and inventory performance where the bullwhip effect reduction might increase inventory instability. Therefore, there is a need for inventory control policies that can cope with supply chain dynamics. This paper proposes an inventory control policy based on a statistical process control approach (SPC) to handle supply chain dynamics. The policy relies on applying individual control charts to control both the inventory position and the placed orders adequately. A simulation study has been conducted to evaluate and compare the proposed SPC policy with a traditional order-up-to in a multi-echelon supply chain. The comparison showed that the SPC policy outperforms the order-up-to in terms of bullwhip effect and inventory performances. The SPC succeeded to eliminate the bullwhip effect whilst keeping a competitive inventory performance. massimo.tronci @uniroma1.it

Inventory control policies have been recognized as a contributory factor to the bullwhip effect a... more Inventory control policies have been recognized as a contributory factor to the bullwhip effect and inventory instability. Previous studies have indicated that there is a trade-off between bullwhip effect and inventory performance where the bullwhip effect reduction might increase inventory instability. Therefore, there is a need for inventory control policies that can cope with supply chain dynamics. This paper proposes an inventory control policy based on a statistical process control approach (SPC) to handle supply chain dynamics. The policy relies on applying individual control charts to control both the inventory position and the placed orders adequately. A simulation study has been conducted to evaluate and compare the proposed SPC policy with a traditional order-up-to in a multi-echelon supply chain. The comparison showed that the SPC policy outperforms the order-up-to in terms of bullwhip effect and inventory performances. The SPC succeeded to eliminate the bullwhip effect whilst keeping a competitive inventory performance. massimo.tronci @uniroma1.it Keyword-Supply Chain, Inventory Control, SPC, Control Chart, Bullwhip Effect, Inventory Variance, Simulation I. INTRODUCTION In supply chains, the variability in the ordering patterns often increases as demand information moves upstream in the supply chain, from the retailer towards the factory and the suppliers. This phenomenon of information distortion has been recognized as the bullwhip effect [1]. Fig. 1 depicts an example of the bullwhip effect in which the orders placed by four supply chain echelons over the same 100 periods are plotted side-by-side. The bullwhip effect has been observed in many industries such as Campbell Soup's [2], HP and Proctor & Gamble [1], fast moving consumer goods [3], and car manufacturing [4]

Inventory replenishment rules have been recognized as a major cause of the bullwhip effect and in... more Inventory replenishment rules have been recognized as a major cause of the bullwhip effect and inventory instability in multi-echelon supply chains. There is a trade-off between bullwhip effect and inventory stability where mitigating the bullwhip effect through order smoothing might increase inventory instability. Therefore, there is a substantial need for inventory control policies that can cope with supply chains dynamics. This paper attempts to formulate an inventory control system based on a statistical control chart approach to handle the trade-off between order variability amplification and inventory stability. The proposed replenishment system, namely IR-SPC, incorporates individual control charts to control both the inventory position and the placed orders. A simulation study has been conducted to evaluate and compare the IR-SPC with a generalized order-up-to that has order smoothing mechanism. The comparisons showed that the IR-SPC outperforms both the smoothing order-up-to policy and the Min-Max inventory policy in terms of bullwhip effect and inventory performances.

The stressing worldwide competition moves organizations to global sourcing to take advantage from... more The stressing worldwide competition moves organizations to global sourcing to take advantage from foreign markets. However, distance and complexity of cooperation and coordination may lead companies to increase their level of stocks. Supply process can apply lean production pillars, overcoming the JIT principle of supplier proximity, to design an innovative lean procurement process for enhancing operations performances. The contribution of this study is 2 fold. First, we present a set of lean practices, suitable to the procurement process, developing a specific framework for global sourcing. Second, we show results of an action research performed to test the framework with real global outsourcing requirements of an Italian company, operating in the electro-mechanical industry.

Bullwhip effect represents the amplification and distortion of demand variability as moving upstr... more Bullwhip effect represents the amplification and distortion of demand variability as moving upstream in a supply chain, causing excessive inventories, insufficient capacities and high operational costs. A growing body of literature recognizes ordering policies and the lack of coordination as two main causes of the bullwhip effect, suggesting different techniques of intervention. This paper investigates the impact of information sharing on ordering policies through a comparison between a traditional (R, S) policy and a coordination mechanism based on ordering policy (a combination of (R, D) and (R, S) policies). This policy relies on a slow, easy to implement, information sharing to overcome drawbacks of the effect, in which replenishment orders are divided into two parts; the first is to inform the upstream echelons about the actual customer demand and the second is to inform about the adjustment of the inventory position, smoothing at the same time the orders of the different levels of the supply chain. A simulation model for a multi-echelon supply chain quantifies the supply chain dynamics under these different policies, identifying how information sharing succeeds to achieve an acceptable performance in terms of both bullwhip effect and inventory variance.

Defining means to assess safety performance and delve into their causes is one of the current and... more Defining means to assess safety performance and delve into their causes is one of the current and future challenges of the air transport sector. This paper develops an improvement of the Air Traffic Management (ATM) safety evaluation in order to develop proactive safety indicators, based on Aerospace Performance Factor and Analytic Hierarchy Process. The research aims to carry out a statistical model of safety events in order to predict safety performance, combining in a Monte Carlo simulation the results emerged from the literature analysis with the analytical models of historic data interpretation. Through the analysis of the possible scenarios, assessing their impact on equipment, procedures and human factor, this model will address the interventions of the decision maker.

Inventory replenishment rules contribute significantly to the bullwhip effect and inventory insta... more Inventory replenishment rules contribute significantly to the bullwhip effect and inventory instability in supply chains. Smoothing replenishment rules have been suggested as a mitigation solution for the bull-whip effect but dampening the bullwhip effect might increase inventory instability. This paper evaluates a real-time inventory replenishment system denoted as SPC that utilizes a control chart approach to counteract the bullwhip effect whilst achieving competitive inventory stability. The SPC employs two control charts integrated with a set of decision rules to estimate the expected demand and adjust the inventory position, respectively. The first control chart works as a forecasting mechanism and the second control chart is devoted to control the inventory position variation whilst allowing order smoothing. A simulation analysis has been conducted to evaluate and compare SPC with a generalized (R, S) policy in a four-echelon supply chain, under various operational settings in terms of demand process, lead-time and information sharing. The results show that SPC is superior to the traditional (R, S) and comparable to the smoothing one in terms of bullwhip effect, inventory variance, and service level. Further managerial implications have been obtained from the results.

Demand signal processing contributes significantly to the bullwhip effect and inventory instabili... more Demand signal processing contributes significantly to the bullwhip effect and inventory instability in supply chains. Most previous studies have been attempting to evaluate the impact of available traditional forecasting methods on the bullwhip effect. Recently, some researchers have employed SPC control charts for developing forecasting and inventory control systems that can regulate the reaction to short-run fluctuations in demand. This paper evaluates a SPC forecasting system denoted as SPC-FS that utilizes a control chart approach integrated with a set of simple decision rules to counteract the bullwhip effect whilst keeping a competitive inventory performance. The performance of SPC-FS is evaluated and compared with moving average and exponential smoothing in a four-echelon supply chain employs the order-up-to (OUT) inventory policy, through a simulation study. The results show that SPC-FS is superior to the other traditional forecasting methods in terms of bullwhip effect and inventory variance under different operational settings. The results confirm the previous researches that the moving average achieves a lower bullwhip effect than the exponential smoothing, and we further extend this conclusion to the inventory variance.

A major cause of supply chain deficiencies is the bullwhip effect, which implies that demand vari... more A major cause of supply chain deficiencies is the bullwhip effect, which implies that demand variability amplifies as one moves upstream in supply chains. Smoothing inventory decision rules have been recognized as the most powerful approach to counteract the bullwhip effect. Although several studies have evaluated these smoothing rules with respect to several demand processes, focusing mainly on the smoothing order-up-to (OUT) replenishment rule, less attention has been devoted to investigate their effectiveness in seasonal supply chains. This research addresses this gap by investigating the impact of the smoothing OUT on the seasonal supply chain performances. A simulation study has been conducted to evaluate and compare the smoothing OUT with the traditional OUT (no smoothing), both integrated with the Holt-Winters (HW) forecasting method, in a four-echelon supply chain experiences seasonal demand modified by random variation. The results show that the smoothing OUT replenishment rule is superior to the traditional OUT, in terms of the bullwhip effect, inventory variance ratio and average fill rate, especially when the seasonal cycle is small. In addition, the sensitivity analysis reveals that employing the smoothing replenishment rules reduces the impact of the demand parameters and the poor selection of the forecasting parameters on the ordering and inventory stability. Therefore, seasonal supply chain managers are strongly recommended to adopt the smoothing replenishment rules. Further managerial implications have been derived from the results.

The supply of spare parts has a crucial role in the aviation sector, mainly due to the high costs... more The supply of spare parts has a crucial role in the aviation sector, mainly due to the high costs of spare parts and to the strict availability requirements. In a stand-alone scenario, an airline owns the spare parts and manages the maintenance tasks by itself. A new trend consists of not owning the spare parts and delegate the maintenance tasks to an external company, taking advantage of a specific Performance Based Contract (PBC). The PBCs aim to reduce the ownership cost for the customer airline, while ensuring a target system performance. Spare parts become a variable cost for the customer airline and a business income for the maintenance supplier, which is commonly another airline. This paper proposes an innovative model, i.e. the PBC-METRIC, which supports the customer airline manager to minimize the spare parts supply cost, in compliance with the airline availability requirements and with respect to the PBC. In detail, the PBC-METRIC models a multi-echelon, multi-item, single-indenture, multi-transportation network, by an innovative two-steps algorithm, defining the PBC specifications as modelling variables and parameters. A case study on a European airline, with the role of customer in a PBC, illustrates the outcome of the model.

Modern trends of socio-technical systems analysis suggest the development of an integrated view o... more Modern trends of socio-technical systems analysis suggest the development of an integrated view on technological, human and organizational system components. The Air Traffic Management (ATM) system can be taken as an example of one of the most critical socio-technical system, deserving particular attention in managing operational risks and safety. In the ATM system environment, the traditional techniques of risk and safety assessment may become ineffective as they miss in identifying the interactions and couplings between the various functional aspects of the system itself: going over the technical analysis, it is necessary to consider the influences between human factors and organizational structure both in everyday work and in abnormal situations. One of the newly introduced methods for understanding these relations is the Functional Resonance Analysis Method (FRAM) which aims to define the couplings among functions in a dynamic way. This paper evolves the traditional FRAM, proposing an innovative semi-quantitative framework based on Monte Carlo simulation. Highlighting critical functions and critical links between functions, this contribution aims to facilitate the safety analysis, taking account of the system response to different operating conditions and different risk state. The paper presents a walk-through section with a general application to an ATM process. © 2016 Elsevier Ltd

Advances in Decision Sciences, 2014

International Journal of Project Management, 2015

Journal of Cleaner Production, 2018

The authors deal with the topic of the final assembly scheduling realized by the use of genetic a... more The authors deal with the topic of the final assembly scheduling realized by the use of genetic algorithms (GAs). The objective of the research was to study in depth the use of GA for scheduling mixed-model assembly lines and to propose a model able to produce feasible solutions also according to the particular requirements of an important Italian motorbike company, as well as to capture the results of this change in terms of better operational performances. The " chessboard shifting " of work teams among the mixed-model assembly lines of the selected company makes the scheduling problem more complex. Therefore, a complex model for scheduling is required. We propose an application of the GAs in order to test their effectiveness to real scheduling problems. The high quality of the final assembly plans with high adherence to the delivery date, obtained in a short elaboration time, confirms that the choice was right and suggests the use of GAs in other complex manufacturing systems.

Defining means to assess safety performance and delve into their causes is one of the current and... more Defining means to assess safety performance and delve into their causes is one of the current and future challenges of the air transport sector. This paper develops an improvement of the Air Traffic Management (ATM) safety evaluation in order to develop proactive safety indicators, based on Aerospace Performance Factor and Analytic Hierarchy Process. The research aims to carry out a statistical model of safety events in order to predict safety performance, combining in a Monte Carlo simulation the results emerged from the literature analysis with the analytical models of historic data interpretation. Through the analysis of the possible scenarios, assessing their impact on equipment, procedures and human factor, this model will address the interventions of the decision maker.

Advances in Decision Sciences, 2014

International Journal of Project Management, 2015