Inventory-pooling (IP) is an effective tool to mitigate demand uncertainty and variability, to re... more Inventory-pooling (IP) is an effective tool to mitigate demand uncertainty and variability, to reduce operational costs, and consequently to increase the profit. The major assumptions of the previous works in literature on IP include the following: (1) Independents demand, which satisfy the typical normal independent and identically distributed (iid) random variables; (2) dependents (correlated) symmetric demands, which follows to a multivariate normal distribution. The effect of the dependent asymmetric demand is not yet studied. The aim of this paper is to consider this more realistic case. Indeed, the contribution of this paper is twofold. Firstly, it analyzes both the sensitivity of dependence structure and the levels of skewness of distributions on IP policies in terms of optimal total cost and demand satisfaction constraint. Secondly, both symmetric and asymmetric demand distributions are modeled using various beta distribution and the dependance between demands are modeled us...
Safety stock (SS) is an appropriate tactic to deal with demand and supply uncertainty with the ai... more Safety stock (SS) is an appropriate tactic to deal with demand and supply uncertainty with the aim of preventing inventory shortages. In the literature, previous work on SS estimation assumes that the forecast error distributions (FED) are independent and identically distributed (i.i.d) following the normal distribution. In order to assess violations of this assumption, there are many solution methods in the recent literature that include the following: (1) Consider the FED as other distribution models, such as gamma distribution or log-normal distribution, etc. (2) Use the Generalized Auto-Regressive Conditional Heteroskedasticity (GARCH) model to consider the Heteroskedasticity phenomena, (3) Use the extreme value theory (EVT) to take into consideration the occurrence of extreme demands, etc. However, the performance of these methods is not guaranteed because there is an absence of comparative studies. Indeed, the estimation of SS is based on the approximation of quantiles of the ...
Port risk management (PRM) during port operations is a current problem that can negatively affect... more Port risk management (PRM) during port operations is a current problem that can negatively affect the environment, people, and economic issues. In the literature, there is an enormous amount of research related to supply chain risk management (SCRM) in various areas and with various objectives. However, PRM has not received the same degree of attention. In fact, port terminals are crucial links in most supply chain networks and an important pillar of international trade. Therefore, for better risk mitigation efficiency, a risk assessment and prioritization step are vital. Recently in the literature, researchers have applied prospective methods such as structural analysis methods to risk prioritization in SCRM. The aim of this research is to prioritize various man-made risk variables in PRM using a qualitative structural modeling-based approach, specifically, the MICMAC method (referring to its French acronym: Matrice d’Impacts Croisés Multiplication Appliquée à un Classement). An em...
Agricultural production of olive oil is a sector with high significance. The olive sector is a ve... more Agricultural production of olive oil is a sector with high significance. The olive sector is a very important sector for several countries in the world, in particular, for Tunisia. In addition, the impacts of olive oil production and extraction on economic, environmental, and social issues are considerable. The main objective of this work is to propose a better configuration of the Tunisian olive oil supply chain (OOSC) from a sustainable development (SD) perspective. The proposed approach consists of applying a fuzzy technique for order preference by similarity to ideal solution (TOPSIS) method as a multi-criteria approach. The proposed approach is applied twice. In the first application, the objective is to compare five possible scenarios for the olive agricultural phase. In the second application, the objective is to compare three possible scenarios for the olive oil transformation phase. The major findings of this research include the following: (1) The best scenario for the agr...
International Journal of Environmental Research and Public Health, 2021
Groundwater (GW) studies have been conducted worldwide with regard to several pressures, includin... more Groundwater (GW) studies have been conducted worldwide with regard to several pressures, including climate change, seawater intrusion, and water overexploitation. GW quality is a very important sector for several countries in the world, in particular for Tunisia. The shallow coastal aquifer of Sfax (located in Tunisia) was found to be under the combined conditions of continuous drop in GW and further deterioration of the groundwater quality (GWQ). This study was conducted to identify the processes that control GWQ mainly in relation to mineralization sources in the shallow Sfax coastal aquifer. To perform this task, 37 wells are considered. Data include 10 physico-chemical properties of groundwater analyzed in water samples: pH, EC, calcium (Ca), sodium (Na), magnesium (Mg), potassium (K), chloride (Cl), sulfate (SO4), bicarbonate (HCO3), and nitrate (NO3), i.e., investigation was based on a database of 370 observations. Principal component analysis (PCA) and hydrochemical facies ev...
Companies attempt to improve the performance of their supply chain (SC) by distinguishing and pre... more Companies attempt to improve the performance of their supply chain (SC) by distinguishing and presenting feasible sustainable development practices (SDP). Considering SDP without focusing on sustainability risks may disturb the company’s future. Very few studies in the extant literature have dealt with the impact of (SDP) on the supply chain risk management (SCRM). In fact, the aim of this paper is to classify and prioritize SDPs according to their priority for better risk management and effective SC performance. The proposed approach comprises two phases. First, 14 SDPs are identified and selected from the literature. Second, MICMAC (Matrice d’impacts croisés multiplication appliquée à un classement) method as a structural analysis method applies to identify and assess sustainable supply chain risk management (SSCRM) practices which reduce risk in the SC. The input data for each phase are based on Delphi technique, which is a process group used to collect the opinions of experts in...
Using an adaptive Mamdani fuzzy inference system model (MFSIM), the purpose of this paper is main... more Using an adaptive Mamdani fuzzy inference system model (MFSIM), the purpose of this paper is mainly to assess and rank the assessment and ranking of water quality for irrigation occurring in the Hammamet-Nabeul (Tunisia) shallow aquifer. This aquifer is under Mediterranean climate conditions and affected by intensive and irrational agricultural activities. In the current study, the Mamdani fuzzy logic-based decision-making approach was adapted to classify groundwater quality (GW) for irrigation. The operation of the fuzzy model is based on the input membership functions of electrical conductivity (EC) and sodium absorption ratio (SAR) and on the output membership function of the irrigation water quality index (IWQI). Validation of the applied MFISM showed a rate of about 80%. Therefore, MFISM was shown to be reliable and flexible in quality ranking for irrigation in an uncertain and complex hydrogeological system. The results demonstrated that water quality contamination in the aqui...
World Review of Intermodal Transportation Research, 2020
This paper deals with a real stochastic infectious healthcare waste (IHW) collection problem. The... more This paper deals with a real stochastic infectious healthcare waste (IHW) collection problem. The waste was collected from all hospitals in the governorate of Sfax (Tunisia) to an incinerator. The reduction of medical infectious waste represents a challenge for Tunisia's commitments in healthcare institutions. This problem is considered as a Capacitated Vehicle Routing Problem with Stochastic Demand (CVRPSD). Two combined approaches are proposed: (1) a combination of exact method with a Monte Carlo simulation, (2) a combination of the same simulation tools with Clarke and Wright (C&W) saving. These proposed approaches provide a set of solutions which help the decision-makers of the Sfax municipality to perform an adequate IHW transportation routing system. The approaches results give one common solution that appears with a high frequency using an exact method despite the stochastic character of demands. The (C&W) heuristic provides good results in a reasonable time.
This synthesis report entitled "Contributions for the improvement of manufacturing and logis... more This synthesis report entitled "Contributions for the improvement of manufacturing and logistics systems" includes all research activities of M. Wafik Hachicha, to obtain a Habilitation degree in “industrial engineering” area from the University of Sfax through an ad-hoc committee which is created for this purpose.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT The performance of the supply chain can be affected by adverse events entering the syste... more ABSTRACT The performance of the supply chain can be affected by adverse events entering the system and affecting all exchanges of products, services and information between actors in a supply chain network. The management of these events is known as Supply Chain Risk Management (SCRM) which is defined, in a collaborative way with partners, as a set of tools for dealing with risk and uncertainty caused by, or having an impact on the activities and logistical resources. In this context, it is important to study the influences of these actors to each other, their strategies, their convergences and divergences of objectives and their balance of power to a better risk management. The purpose of this paper is to apply MACTOR (Matrix of Alliances and Conflicts: Tactics, Objectives and Recommendations) method to evaluate the balance of power between supply actors. Then, actors' convergences and divergences towards a number of issues and objectives associated with risk management are analyzed. Therefore, the most suitable risk mitigation strategies for each supply actor are constructed. A real case study in food industry is provided in order to illustrate the application of MACTOR method. The findings are very useful for all supply actors and it may also useful to the practitioners in risk management, since the method used here can be applied in other areas of management as well.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT Infectious Healthcare-Waste (IHW) management is of great importance due to its potential... more ABSTRACT Infectious Healthcare-Waste (IHW) management is of great importance due to its potential environmental hazards and public health risks. The collection and the disposal of IHW are highly visible and important services that involve large expenditures in the world and particularly in Tunisia. This paper discusses two main problems in the current solid IHW management practices in Sfax governorate (Tunisia). The first problem is about how choose the best waste treatment and disposal scenario, using a multiple criteria decision making analysis. The Analytic hierarchy process (AHP) implemented with Expert choice software, confirms that the best scenario is to apply central steam sterilization equipment, which will be used by all hospitals. Accordingly, the second problem concerns the off-site transport of IHW from the twelve hospitals (public and private) in the governorate of Sfax to this overall center. This problem of transportation is modeled as a capacitated vehicle routing problem (CVRP). Experimental results are reported for the design of the routing system for IHW transportation, using the solver CPLEX 9.0 software. Future legislation concerning IHW management is supposed to take into account the various results of this research.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT In this paper, a single-stage inventory system, which analytical method results exist in... more ABSTRACT In this paper, a single-stage inventory system, which analytical method results exist in previous literature is considered. This case is one of an adaptive base-stock policy for a single-item inventory system, where the demand process is nostationary. The demand process is modeled as an integrated moving average process for which an exponential-weighted moving average provides the optimal forecast. The case study objective is about how characterize the required inventory and how identify the safety stock requirements. For this purpose, a system dynamics approach is developed through a flow diagram model and simulated using Vensim® software. The results of the comparative study show that system dynamics approach is very useful. The system dynamics models can provide increased comprehension of, and improved insight into, the performance of an inventory system. The extension of system dynamics seems very interesting for the analysis of complex supply chain problems. In fact, analytical methods are perceived to be unhelpful by management or may require oversimplification.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT Modern supply chains are very complex and suffer always from various risks. An effective... more ABSTRACT Modern supply chains are very complex and suffer always from various risks. An effective supply chain management requires suitable strategies to mitigate them. In literature, there has been a range of research into risk in purchasing and supply, but little in global and integrated supply networks. This can be explained due to the huge number of risk variables and their direct and indirect interrelations that may suffer all supply chain partners. Therefore, for better risk management process, the risk prioritization step is vital. The purpose of this paper is to apply a structural modeling technique for risk analysis and prioritization through a real case study of Masmoudi pastry supply network. Firstly, thirty risk variables have been identified through literature survey, interaction with industry experts, and various interviews with the supply key managers. Secondly, MICMAC method is applied to recognize both direct and indirect relationships between these thirty risk variables, and to ascertain the most prioritized risk variables. This prioritization provides a useful tool to Masmoudi pastry managers to differentiate between independent and dependent risk variables and their mutual relationships which would help them to focus on those key variables that are most important for an effective risk mitigation management.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT This paper deals with a lateral transshipment models involving two-echelon supply chain ... more ABSTRACT This paper deals with a lateral transshipment models involving two-echelon supply chain network, with a single supplier at the higher echelon and two retail locations at the lower. Lateral transshipment is considered as an option at each reorder decision under the periodic review standard (R, s, S) replenishment policy. The purpose of this paper is twofold. Firstly, a metamodel-based simulation optimization approach is applied to find the optimal values of s and S, for each retailer. Secondly, a series of simulation experiments are performed to find the best transshipment policy, in terms of smallest total cost and disservice rate. The tested policies are no pooling, complete pooling and various partial pooling policies according to what the threshold levels of physical stock are selected. An important finding is that each tested transshipment policy is considerably superior to a policy of no such transshipments, although at the expense of increased transportation activity. The best transshipment policy is such partial pooling with exactly s as the well-chosen value of the threshold level. Partial pooling is very interesting transshipment policy and should be further addressed in future research.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT Risk management and performance measurement should be linked together to enable, to each... more ABSTRACT Risk management and performance measurement should be linked together to enable, to each supply chain partner, to define and guide its overall risk profile, as well as to shape its strategic direction. In this frame, the aim of this paper is to propose and to validate an integrated approach for relating risk management into supply chain performance measurement system. The proposed approach is carried out in two sequential phases. After identifying flow, missions and goals of an organization, the first phase focuses on the application of the Supply chain operations reference (SCOR) model and the Activity Breakdown Structure (ABS) to identify supply chain processes and activities. After that, Risk Breakdown Structure (RBS) and Risk Breakdown Matrix (RBM) are applied to identify critical risks and to give a set of performance metrics that is based on those risks. Finally, the second phase completes this set by using the Balanced Scorecard (BSC) framework. For a validation purpose, the proposed approach is applied to the Higher Institute of Industrial Management (ISGI, Sfax-Tunisia) library. A comparative analysis between the identified metrics and those required by the standard ISO 11620 (version 2008) shows the significance and the importance of the proposed approach.
Supply networks are complex and suffer always from various risks. An effective supply chain manag... more Supply networks are complex and suffer always from various risks. An effective supply chain management requires suitable strategies to mitigate them. In previous literature, there has been a range of research into risk in firms but little in supply networks. This can be explained due to the huge number of risk variables and their direct and indirect interrelations that may suffer all supply chain partners (firms). Therefore, for better risk mitigation, a risk prioritization step is vital. To this end, the purpose of this paper is to propose a new integrated approach based on two structural modeling tools. Firstly, interpretive structural modeling has been used to present a hierarchical model showing the interrelationships between the risk sources. Secondly, MICMAC analysis has been used to quantify and classify the risk variables based on their mutual influence and dependence. The objective is to ascertain the key risk variables and theirs relationships. These prioritized risk variables provide a useful tool to supply network managers to focus on those key variables that are most essential for effective risk management strategies. A real case study in food industry is provided in order to illustrate the application of the proposed approach. The findings may be useful to the practitioners in risk management and may also interest academicians, since the method used here can be applied in other areas of industrial management as well.
International Journal of Automation and Control, 2012
The aim of this research is to expand a framework that integrates two important concepts: statist... more The aim of this research is to expand a framework that integrates two important concepts: statistical process control (SPC) and engineering process control (EPC). Most of the literature researches on integrated SPC/EPC systems are focused into continuous process mainly with algorithmic SPC. The integrated SPC/EPC systems in batch process control have not received the same degree of attention. This paper is a first of its kind in integrated SPC/EPC systems that applied in batch process. The proposed SPC/EPC integration is performed continually in active SPC for the batch making advance and in run-to-run (RTR) control action between batches. As a validation step, the proposed approach is applied to an industrial batch alkyd polymerisation reactor. Through this case study application, process engineers at the company are now able to use a valuable decision making tool when the production process is affected by certain disruptions, with obvious consequences on product quality, productivity and competitiveness.
Inventory-pooling (IP) is an effective tool to mitigate demand uncertainty and variability, to re... more Inventory-pooling (IP) is an effective tool to mitigate demand uncertainty and variability, to reduce operational costs, and consequently to increase the profit. The major assumptions of the previous works in literature on IP include the following: (1) Independents demand, which satisfy the typical normal independent and identically distributed (iid) random variables; (2) dependents (correlated) symmetric demands, which follows to a multivariate normal distribution. The effect of the dependent asymmetric demand is not yet studied. The aim of this paper is to consider this more realistic case. Indeed, the contribution of this paper is twofold. Firstly, it analyzes both the sensitivity of dependence structure and the levels of skewness of distributions on IP policies in terms of optimal total cost and demand satisfaction constraint. Secondly, both symmetric and asymmetric demand distributions are modeled using various beta distribution and the dependance between demands are modeled us...
Safety stock (SS) is an appropriate tactic to deal with demand and supply uncertainty with the ai... more Safety stock (SS) is an appropriate tactic to deal with demand and supply uncertainty with the aim of preventing inventory shortages. In the literature, previous work on SS estimation assumes that the forecast error distributions (FED) are independent and identically distributed (i.i.d) following the normal distribution. In order to assess violations of this assumption, there are many solution methods in the recent literature that include the following: (1) Consider the FED as other distribution models, such as gamma distribution or log-normal distribution, etc. (2) Use the Generalized Auto-Regressive Conditional Heteroskedasticity (GARCH) model to consider the Heteroskedasticity phenomena, (3) Use the extreme value theory (EVT) to take into consideration the occurrence of extreme demands, etc. However, the performance of these methods is not guaranteed because there is an absence of comparative studies. Indeed, the estimation of SS is based on the approximation of quantiles of the ...
Port risk management (PRM) during port operations is a current problem that can negatively affect... more Port risk management (PRM) during port operations is a current problem that can negatively affect the environment, people, and economic issues. In the literature, there is an enormous amount of research related to supply chain risk management (SCRM) in various areas and with various objectives. However, PRM has not received the same degree of attention. In fact, port terminals are crucial links in most supply chain networks and an important pillar of international trade. Therefore, for better risk mitigation efficiency, a risk assessment and prioritization step are vital. Recently in the literature, researchers have applied prospective methods such as structural analysis methods to risk prioritization in SCRM. The aim of this research is to prioritize various man-made risk variables in PRM using a qualitative structural modeling-based approach, specifically, the MICMAC method (referring to its French acronym: Matrice d’Impacts Croisés Multiplication Appliquée à un Classement). An em...
Agricultural production of olive oil is a sector with high significance. The olive sector is a ve... more Agricultural production of olive oil is a sector with high significance. The olive sector is a very important sector for several countries in the world, in particular, for Tunisia. In addition, the impacts of olive oil production and extraction on economic, environmental, and social issues are considerable. The main objective of this work is to propose a better configuration of the Tunisian olive oil supply chain (OOSC) from a sustainable development (SD) perspective. The proposed approach consists of applying a fuzzy technique for order preference by similarity to ideal solution (TOPSIS) method as a multi-criteria approach. The proposed approach is applied twice. In the first application, the objective is to compare five possible scenarios for the olive agricultural phase. In the second application, the objective is to compare three possible scenarios for the olive oil transformation phase. The major findings of this research include the following: (1) The best scenario for the agr...
International Journal of Environmental Research and Public Health, 2021
Groundwater (GW) studies have been conducted worldwide with regard to several pressures, includin... more Groundwater (GW) studies have been conducted worldwide with regard to several pressures, including climate change, seawater intrusion, and water overexploitation. GW quality is a very important sector for several countries in the world, in particular for Tunisia. The shallow coastal aquifer of Sfax (located in Tunisia) was found to be under the combined conditions of continuous drop in GW and further deterioration of the groundwater quality (GWQ). This study was conducted to identify the processes that control GWQ mainly in relation to mineralization sources in the shallow Sfax coastal aquifer. To perform this task, 37 wells are considered. Data include 10 physico-chemical properties of groundwater analyzed in water samples: pH, EC, calcium (Ca), sodium (Na), magnesium (Mg), potassium (K), chloride (Cl), sulfate (SO4), bicarbonate (HCO3), and nitrate (NO3), i.e., investigation was based on a database of 370 observations. Principal component analysis (PCA) and hydrochemical facies ev...
Companies attempt to improve the performance of their supply chain (SC) by distinguishing and pre... more Companies attempt to improve the performance of their supply chain (SC) by distinguishing and presenting feasible sustainable development practices (SDP). Considering SDP without focusing on sustainability risks may disturb the company’s future. Very few studies in the extant literature have dealt with the impact of (SDP) on the supply chain risk management (SCRM). In fact, the aim of this paper is to classify and prioritize SDPs according to their priority for better risk management and effective SC performance. The proposed approach comprises two phases. First, 14 SDPs are identified and selected from the literature. Second, MICMAC (Matrice d’impacts croisés multiplication appliquée à un classement) method as a structural analysis method applies to identify and assess sustainable supply chain risk management (SSCRM) practices which reduce risk in the SC. The input data for each phase are based on Delphi technique, which is a process group used to collect the opinions of experts in...
Using an adaptive Mamdani fuzzy inference system model (MFSIM), the purpose of this paper is main... more Using an adaptive Mamdani fuzzy inference system model (MFSIM), the purpose of this paper is mainly to assess and rank the assessment and ranking of water quality for irrigation occurring in the Hammamet-Nabeul (Tunisia) shallow aquifer. This aquifer is under Mediterranean climate conditions and affected by intensive and irrational agricultural activities. In the current study, the Mamdani fuzzy logic-based decision-making approach was adapted to classify groundwater quality (GW) for irrigation. The operation of the fuzzy model is based on the input membership functions of electrical conductivity (EC) and sodium absorption ratio (SAR) and on the output membership function of the irrigation water quality index (IWQI). Validation of the applied MFISM showed a rate of about 80%. Therefore, MFISM was shown to be reliable and flexible in quality ranking for irrigation in an uncertain and complex hydrogeological system. The results demonstrated that water quality contamination in the aqui...
World Review of Intermodal Transportation Research, 2020
This paper deals with a real stochastic infectious healthcare waste (IHW) collection problem. The... more This paper deals with a real stochastic infectious healthcare waste (IHW) collection problem. The waste was collected from all hospitals in the governorate of Sfax (Tunisia) to an incinerator. The reduction of medical infectious waste represents a challenge for Tunisia's commitments in healthcare institutions. This problem is considered as a Capacitated Vehicle Routing Problem with Stochastic Demand (CVRPSD). Two combined approaches are proposed: (1) a combination of exact method with a Monte Carlo simulation, (2) a combination of the same simulation tools with Clarke and Wright (C&W) saving. These proposed approaches provide a set of solutions which help the decision-makers of the Sfax municipality to perform an adequate IHW transportation routing system. The approaches results give one common solution that appears with a high frequency using an exact method despite the stochastic character of demands. The (C&W) heuristic provides good results in a reasonable time.
This synthesis report entitled "Contributions for the improvement of manufacturing and logis... more This synthesis report entitled "Contributions for the improvement of manufacturing and logistics systems" includes all research activities of M. Wafik Hachicha, to obtain a Habilitation degree in “industrial engineering” area from the University of Sfax through an ad-hoc committee which is created for this purpose.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT The performance of the supply chain can be affected by adverse events entering the syste... more ABSTRACT The performance of the supply chain can be affected by adverse events entering the system and affecting all exchanges of products, services and information between actors in a supply chain network. The management of these events is known as Supply Chain Risk Management (SCRM) which is defined, in a collaborative way with partners, as a set of tools for dealing with risk and uncertainty caused by, or having an impact on the activities and logistical resources. In this context, it is important to study the influences of these actors to each other, their strategies, their convergences and divergences of objectives and their balance of power to a better risk management. The purpose of this paper is to apply MACTOR (Matrix of Alliances and Conflicts: Tactics, Objectives and Recommendations) method to evaluate the balance of power between supply actors. Then, actors' convergences and divergences towards a number of issues and objectives associated with risk management are analyzed. Therefore, the most suitable risk mitigation strategies for each supply actor are constructed. A real case study in food industry is provided in order to illustrate the application of MACTOR method. The findings are very useful for all supply actors and it may also useful to the practitioners in risk management, since the method used here can be applied in other areas of management as well.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT Infectious Healthcare-Waste (IHW) management is of great importance due to its potential... more ABSTRACT Infectious Healthcare-Waste (IHW) management is of great importance due to its potential environmental hazards and public health risks. The collection and the disposal of IHW are highly visible and important services that involve large expenditures in the world and particularly in Tunisia. This paper discusses two main problems in the current solid IHW management practices in Sfax governorate (Tunisia). The first problem is about how choose the best waste treatment and disposal scenario, using a multiple criteria decision making analysis. The Analytic hierarchy process (AHP) implemented with Expert choice software, confirms that the best scenario is to apply central steam sterilization equipment, which will be used by all hospitals. Accordingly, the second problem concerns the off-site transport of IHW from the twelve hospitals (public and private) in the governorate of Sfax to this overall center. This problem of transportation is modeled as a capacitated vehicle routing problem (CVRP). Experimental results are reported for the design of the routing system for IHW transportation, using the solver CPLEX 9.0 software. Future legislation concerning IHW management is supposed to take into account the various results of this research.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT In this paper, a single-stage inventory system, which analytical method results exist in... more ABSTRACT In this paper, a single-stage inventory system, which analytical method results exist in previous literature is considered. This case is one of an adaptive base-stock policy for a single-item inventory system, where the demand process is nostationary. The demand process is modeled as an integrated moving average process for which an exponential-weighted moving average provides the optimal forecast. The case study objective is about how characterize the required inventory and how identify the safety stock requirements. For this purpose, a system dynamics approach is developed through a flow diagram model and simulated using Vensim® software. The results of the comparative study show that system dynamics approach is very useful. The system dynamics models can provide increased comprehension of, and improved insight into, the performance of an inventory system. The extension of system dynamics seems very interesting for the analysis of complex supply chain problems. In fact, analytical methods are perceived to be unhelpful by management or may require oversimplification.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT Modern supply chains are very complex and suffer always from various risks. An effective... more ABSTRACT Modern supply chains are very complex and suffer always from various risks. An effective supply chain management requires suitable strategies to mitigate them. In literature, there has been a range of research into risk in purchasing and supply, but little in global and integrated supply networks. This can be explained due to the huge number of risk variables and their direct and indirect interrelations that may suffer all supply chain partners. Therefore, for better risk management process, the risk prioritization step is vital. The purpose of this paper is to apply a structural modeling technique for risk analysis and prioritization through a real case study of Masmoudi pastry supply network. Firstly, thirty risk variables have been identified through literature survey, interaction with industry experts, and various interviews with the supply key managers. Secondly, MICMAC method is applied to recognize both direct and indirect relationships between these thirty risk variables, and to ascertain the most prioritized risk variables. This prioritization provides a useful tool to Masmoudi pastry managers to differentiate between independent and dependent risk variables and their mutual relationships which would help them to focus on those key variables that are most important for an effective risk mitigation management.
2013 International Conference on Advanced Logistics and Transport, 2013
ABSTRACT This paper deals with a lateral transshipment models involving two-echelon supply chain ... more ABSTRACT This paper deals with a lateral transshipment models involving two-echelon supply chain network, with a single supplier at the higher echelon and two retail locations at the lower. Lateral transshipment is considered as an option at each reorder decision under the periodic review standard (R, s, S) replenishment policy. The purpose of this paper is twofold. Firstly, a metamodel-based simulation optimization approach is applied to find the optimal values of s and S, for each retailer. Secondly, a series of simulation experiments are performed to find the best transshipment policy, in terms of smallest total cost and disservice rate. The tested policies are no pooling, complete pooling and various partial pooling policies according to what the threshold levels of physical stock are selected. An important finding is that each tested transshipment policy is considerably superior to a policy of no such transshipments, although at the expense of increased transportation activity. The best transshipment policy is such partial pooling with exactly s as the well-chosen value of the threshold level. Partial pooling is very interesting transshipment policy and should be further addressed in future research.
2014 International Conference on Advanced Logistics and Transport (ICALT), 2014
ABSTRACT Risk management and performance measurement should be linked together to enable, to each... more ABSTRACT Risk management and performance measurement should be linked together to enable, to each supply chain partner, to define and guide its overall risk profile, as well as to shape its strategic direction. In this frame, the aim of this paper is to propose and to validate an integrated approach for relating risk management into supply chain performance measurement system. The proposed approach is carried out in two sequential phases. After identifying flow, missions and goals of an organization, the first phase focuses on the application of the Supply chain operations reference (SCOR) model and the Activity Breakdown Structure (ABS) to identify supply chain processes and activities. After that, Risk Breakdown Structure (RBS) and Risk Breakdown Matrix (RBM) are applied to identify critical risks and to give a set of performance metrics that is based on those risks. Finally, the second phase completes this set by using the Balanced Scorecard (BSC) framework. For a validation purpose, the proposed approach is applied to the Higher Institute of Industrial Management (ISGI, Sfax-Tunisia) library. A comparative analysis between the identified metrics and those required by the standard ISO 11620 (version 2008) shows the significance and the importance of the proposed approach.
Supply networks are complex and suffer always from various risks. An effective supply chain manag... more Supply networks are complex and suffer always from various risks. An effective supply chain management requires suitable strategies to mitigate them. In previous literature, there has been a range of research into risk in firms but little in supply networks. This can be explained due to the huge number of risk variables and their direct and indirect interrelations that may suffer all supply chain partners (firms). Therefore, for better risk mitigation, a risk prioritization step is vital. To this end, the purpose of this paper is to propose a new integrated approach based on two structural modeling tools. Firstly, interpretive structural modeling has been used to present a hierarchical model showing the interrelationships between the risk sources. Secondly, MICMAC analysis has been used to quantify and classify the risk variables based on their mutual influence and dependence. The objective is to ascertain the key risk variables and theirs relationships. These prioritized risk variables provide a useful tool to supply network managers to focus on those key variables that are most essential for effective risk management strategies. A real case study in food industry is provided in order to illustrate the application of the proposed approach. The findings may be useful to the practitioners in risk management and may also interest academicians, since the method used here can be applied in other areas of industrial management as well.
International Journal of Automation and Control, 2012
The aim of this research is to expand a framework that integrates two important concepts: statist... more The aim of this research is to expand a framework that integrates two important concepts: statistical process control (SPC) and engineering process control (EPC). Most of the literature researches on integrated SPC/EPC systems are focused into continuous process mainly with algorithmic SPC. The integrated SPC/EPC systems in batch process control have not received the same degree of attention. This paper is a first of its kind in integrated SPC/EPC systems that applied in batch process. The proposed SPC/EPC integration is performed continually in active SPC for the batch making advance and in run-to-run (RTR) control action between batches. As a validation step, the proposed approach is applied to an industrial batch alkyd polymerisation reactor. Through this case study application, process engineers at the company are now able to use a valuable decision making tool when the production process is affected by certain disruptions, with obvious consequences on product quality, productivity and competitiveness.
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Papers by Wafik HACHICHA