Conceptual Modeling for Discrete-Event Simulation, 2010
First published in September 2007, the Systems Modeling Language (SysML) is a recent language for... more First published in September 2007, the Systems Modeling Language (SysML) is a recent language for systems modeling that has a growing community of users and advocates in the field of systems engineering. This chapter gives an overview of SysML, identifies why it is ...
In recent years outsourcing has received greater attention, thus increasing the complexity of the... more In recent years outsourcing has received greater attention, thus increasing the complexity of the supply chain of most products and services. As a consequence, in order to control the relationships between echelons in the supply chain more contracts are now being entered into. These contracts can be difficult to cost due to the fact that they can contain operational details regarding the service to be provided. Further to this, the fast pace of modern industry means that the time in which a contract must be costed is decreasing. Through a survey of the supply chain software sector and interaction with outsourcing enterprises, no software has been identified that specifically deals with this issue. This paper presents work carried out on the development of a prototype web based tool with an embedded simulation engine that focuses on alleviating this contract costing difficulty.
This paper presents an example supply chain application of simulation based decision support. Spe... more This paper presents an example supply chain application of simulation based decision support. Specifically, the paper focuses on contract costing in electronics contract manu- facturing where a study of current practices showed that costing methods used do not capture the cost implications of operational contract stipulations. Discrete event simulation is proposed as a means of supporting more in-depth costing and risk analysis. However, as simulation requires specific expertise not typically available in companies there is need to embed simulation in an application that is easy to use and maintain. A web-based simulation application for contract costing in outsourcing enterprises is presented. The example presented demonstrates the advantages of web-based sim- ulation applications and highlights the need for improved development environments in this area.
Abstract Across the European Economic Area (EEA) more goods are being transported over longer dis... more Abstract Across the European Economic Area (EEA) more goods are being transported over longer distances more frequently than ever before. As a result, Greenhouse Gas emissions from transport increased overall by 28% between 1990 and 2006 for the 32 countries in the EEA. With incoming Kyoto regulations, and opinion resistant to heavy freight traffic, efficient freight transport has become a growing concern. This paper will document the tools already used in environmental supply chain (SC) analysis and investigate the potential use of ...
International Journal of Production Research, 2008
Outsourcing is a major driver in the growth of virtual organizations (VOs) in the manufacturing d... more Outsourcing is a major driver in the growth of virtual organizations (VOs) in the manufacturing domain. These outsourcing networks can be classified as VOs as they are created from different organizational entities for a specific purpose and exist for a specified period of time. This paper proposes the use of discrete event simulation (DES) as a means of evaluating proposed VO configurations within the request for quotation (RFQ) process. The work presented is targeted at manufacturing-based VOs that are created to carry out ...
International Journal of Production Economics, 2007
Outsourcing is a business strategy that has received much attention. An increase in outsourcing h... more Outsourcing is a business strategy that has received much attention. An increase in outsourcing has a direct influence on the complexity of supply chain networks and on the number of contracts required to manage a supply chain. Outsourcing contracts may be entered into relatively quickly without a full understanding of the true cost implications. The research described here aims to develop tools based on discrete-event simulation to aid outsourcing companies when costing contracts. Currently available software for this type ...
As a managerial strategy, outsourcing has been receiving greater attention in recent years, thus ... more As a managerial strategy, outsourcing has been receiving greater attention in recent years, thus increasing the complexity of the supply chain of most products and services. As a consequence, in order to control the relationships between echelons in the supply chain there are now more contracts being entered into. These contracts can be difficult to cost due to the fact that they contain operational details. Further to this, the fast pace of modern industry means that the time in which a contract must be costed is decreasing. Through a survey of the supply chain software sector and interaction with outsourcing enterprises, no software has been identified that specifically deals with this issue. This paper presents work carried out on a prototype web based tool with an embedded simulation engine that focuses on alleviating this contract costing difficulty.
The process of knowledge gathering and system definition is an important and time-consuming activ... more The process of knowledge gathering and system definition is an important and time-consuming activity in large discrete event simulation projects. Furthermore, discrete event simulations are usually developed for a specific problem, and not reused. A result of this is that the ...
Discrete event simulation (DES) is a valuable tool in the manufacturing sector due to its flexibi... more Discrete event simulation (DES) is a valuable tool in the manufacturing sector due to its flexibility and ability to model even very complex systems, given sufficient time and resources. Despite its strengths, there seems to be less penetration in this industry than expected. Models are typically one-off projects that are not maintained beyond the initial analysis. Industry based research conducted through the Irish Centre for Manufacturing Research suggests that due to cost and licensing restrictions, modelling is limited to a single user and consequently the associated skillsets are not developed more widely across the organisation. A possible solution is the use of open source DES which does not carry the same cost and licensing restrictions as the equivalent proprietary software. This paper reports on some of the open source packages currently on offer and provides a case study based comparison of open source and proprietary DES software.
With the increasing trend towards edge and fog computing, the aim of the RECAP simulator is to si... more With the increasing trend towards edge and fog computing, the aim of the RECAP simulator is to simulate large scale scenarios in the cloud, fog and edge computing space in order to provide decision and control support for application and data center resource administration. This will be accomplished through the simulation of applications and application subsystems, simulation of infrastructure resources and resource management systems, and experimentation and validation of simulation results. The RECAP simulator and associated models will provide support for understanding and predicting impact on resources, workloads and quality of service (QoS) metrics as well as trade-offs for energy efficiency and cost within cloud, edge and fog computing scenarios, while maintaining the service level agreements (SLAs) of users.
Call centers have been the subject of many simulation studies and the challenges and successes of... more Call centers have been the subject of many simulation studies and the challenges and successes of modelling these environments have been widely published. Call centers have however evolved significantly in the last decade or so, as new communication technologies have become available, customer expectations have increased, and the value of customer experience has been recognized and prioritized. While the single-channel call centers proved complex to analyze and worthy of the advanced analytical power of simulation, the modern multi-channel connection centers bring new levels of complexity to managerial decision making. This paper presents research into the modelling challenges posed by these evolving environments and illustrates how simulation is now more beneficial than ever to organizations aiming to understand and quantify the impact of change in their customer support business.
Outsourcing is becoming more important in the world economy and is a business approach that is in... more Outsourcing is becoming more important in the world economy and is a business approach that is increasing worldwide. As a consequence of this trend, complex supply chains have been created where suppliers can be located throughout the world, with companies who outsource moving increasingly towards multiple suppliers and short-term contracts. Before establishing these contracts, buyers generally issue a request for quotation (RFQ) to a number of potential suppliers who are capable of delivering a specific product(s)/service(s). In responding to these RFQs, suppliers must cost their quotation and respond to the buyer within an agreed timeframe. This can be difficult as the timeframe can be relatively short and many of these contracts contain operational details. This paper presents work carried out on developing an application that aids suppliers in the costing of their contracts. This application is web-based, and utilizes a hybrid simulation and animation (S&A) approach in its implementation.
Across the European Economic Area more goods are being transported over longer distances more fre... more Across the European Economic Area more goods are being transported over longer distances more frequently than ever before. As a result, Greenhouse Gas (GHG) emissions from transport increased overall by 24% between 1990 and 2003 for the 32 countries in the EEA, with emissions from the transport sector in Ireland growing by 130% in the same period. With incoming Kyoto regulations, and opinion resistant to heavy freight traffic, efficient freight transport has become growing concern. This paper will document the tools already used in environmental Supply Chain (SC) analysis and propose the use of Discrete Event Simulation (DES) as a Decision Support System (DSS) to aid decision makers choose the most environmentally friendly SC design.
Objectives & Background The average age of patients occupying the ED in Beaumont ED is seen t... more Objectives & Background The average age of patients occupying the ED in Beaumont ED is seen to be rising and this fact coupled with an aging population points to potential future demand pressures on ED departments. This research looks at the changing age profile of patients that attend the ED and the relationship between age and waiting time or Patient Experience Time (PET) in the ED. This research is part of a wider research project looking to simulate patient flows through the ED. Methods We analysed a 10 year dataset from the ED at Beaumont Hospital to study trends in average patient age and PETs. We then applied linear regression to the 2013 data, (60,000 patient visits to the ED), to examine the relationship between age and PET. Three separate models were developed with PET, time from admission to first medical and time from bed request to being admitted to hospital as the respective dependent variables. These models also controlled for triage type, patient admitted (Yes/No), number in ED and other factors. Results The average age of ED patients has risen from 43.8 years in 2005 to 48.2 years in 2014 (Figure 1). These older patients have a greater likelihood of admission and in addition experience longer waiting times in ED (See Figures 2 and 3). Using a regression analysis, age was seen to contribute an extra half an hour in PET per 10 year increase. Age had, in contrast, a negative effect on time to first medical with lower waiting times for older age groups. In the final model, predicting the patient time from bed request to being admitted to hospital, age emerged as the most significant factor, with older patients experiencing significantly longer waits. Figure 4 demonstrates these findings, in particular the significant proportion of PET for older patients due to bed requests. Conclusion Age has a significant effect on patient experience time in the ED. The time to first medical care is mainly driven by triage category, but even controlling for this, older people receive care faster. However, subsequently older patients spend longer in the ED and this is due to longer waits for older patients for a hospital bed. The result is an ED populated with elderly boarders. With an ageing national population in Ireland this research emphasises a need to plan for the future healthcare of elderly patients within and beyond acute hospitals. Figure 1 Average Age of Beaumont ED Attendees. Figure 2 Age profile of Beaumont ED Patients (Admitted and Discharged). Figure 3 Average Patient Experience Time per Age Band for Admitted and Discharged Patients. Figure 4 Waiting Times by Age Band (2014).
Conceptual Modeling for Discrete-Event Simulation, 2010
First published in September 2007, the Systems Modeling Language (SysML) is a recent language for... more First published in September 2007, the Systems Modeling Language (SysML) is a recent language for systems modeling that has a growing community of users and advocates in the field of systems engineering. This chapter gives an overview of SysML, identifies why it is ...
In recent years outsourcing has received greater attention, thus increasing the complexity of the... more In recent years outsourcing has received greater attention, thus increasing the complexity of the supply chain of most products and services. As a consequence, in order to control the relationships between echelons in the supply chain more contracts are now being entered into. These contracts can be difficult to cost due to the fact that they can contain operational details regarding the service to be provided. Further to this, the fast pace of modern industry means that the time in which a contract must be costed is decreasing. Through a survey of the supply chain software sector and interaction with outsourcing enterprises, no software has been identified that specifically deals with this issue. This paper presents work carried out on the development of a prototype web based tool with an embedded simulation engine that focuses on alleviating this contract costing difficulty.
This paper presents an example supply chain application of simulation based decision support. Spe... more This paper presents an example supply chain application of simulation based decision support. Specifically, the paper focuses on contract costing in electronics contract manu- facturing where a study of current practices showed that costing methods used do not capture the cost implications of operational contract stipulations. Discrete event simulation is proposed as a means of supporting more in-depth costing and risk analysis. However, as simulation requires specific expertise not typically available in companies there is need to embed simulation in an application that is easy to use and maintain. A web-based simulation application for contract costing in outsourcing enterprises is presented. The example presented demonstrates the advantages of web-based sim- ulation applications and highlights the need for improved development environments in this area.
Abstract Across the European Economic Area (EEA) more goods are being transported over longer dis... more Abstract Across the European Economic Area (EEA) more goods are being transported over longer distances more frequently than ever before. As a result, Greenhouse Gas emissions from transport increased overall by 28% between 1990 and 2006 for the 32 countries in the EEA. With incoming Kyoto regulations, and opinion resistant to heavy freight traffic, efficient freight transport has become a growing concern. This paper will document the tools already used in environmental supply chain (SC) analysis and investigate the potential use of ...
International Journal of Production Research, 2008
Outsourcing is a major driver in the growth of virtual organizations (VOs) in the manufacturing d... more Outsourcing is a major driver in the growth of virtual organizations (VOs) in the manufacturing domain. These outsourcing networks can be classified as VOs as they are created from different organizational entities for a specific purpose and exist for a specified period of time. This paper proposes the use of discrete event simulation (DES) as a means of evaluating proposed VO configurations within the request for quotation (RFQ) process. The work presented is targeted at manufacturing-based VOs that are created to carry out ...
International Journal of Production Economics, 2007
Outsourcing is a business strategy that has received much attention. An increase in outsourcing h... more Outsourcing is a business strategy that has received much attention. An increase in outsourcing has a direct influence on the complexity of supply chain networks and on the number of contracts required to manage a supply chain. Outsourcing contracts may be entered into relatively quickly without a full understanding of the true cost implications. The research described here aims to develop tools based on discrete-event simulation to aid outsourcing companies when costing contracts. Currently available software for this type ...
As a managerial strategy, outsourcing has been receiving greater attention in recent years, thus ... more As a managerial strategy, outsourcing has been receiving greater attention in recent years, thus increasing the complexity of the supply chain of most products and services. As a consequence, in order to control the relationships between echelons in the supply chain there are now more contracts being entered into. These contracts can be difficult to cost due to the fact that they contain operational details. Further to this, the fast pace of modern industry means that the time in which a contract must be costed is decreasing. Through a survey of the supply chain software sector and interaction with outsourcing enterprises, no software has been identified that specifically deals with this issue. This paper presents work carried out on a prototype web based tool with an embedded simulation engine that focuses on alleviating this contract costing difficulty.
The process of knowledge gathering and system definition is an important and time-consuming activ... more The process of knowledge gathering and system definition is an important and time-consuming activity in large discrete event simulation projects. Furthermore, discrete event simulations are usually developed for a specific problem, and not reused. A result of this is that the ...
Discrete event simulation (DES) is a valuable tool in the manufacturing sector due to its flexibi... more Discrete event simulation (DES) is a valuable tool in the manufacturing sector due to its flexibility and ability to model even very complex systems, given sufficient time and resources. Despite its strengths, there seems to be less penetration in this industry than expected. Models are typically one-off projects that are not maintained beyond the initial analysis. Industry based research conducted through the Irish Centre for Manufacturing Research suggests that due to cost and licensing restrictions, modelling is limited to a single user and consequently the associated skillsets are not developed more widely across the organisation. A possible solution is the use of open source DES which does not carry the same cost and licensing restrictions as the equivalent proprietary software. This paper reports on some of the open source packages currently on offer and provides a case study based comparison of open source and proprietary DES software.
With the increasing trend towards edge and fog computing, the aim of the RECAP simulator is to si... more With the increasing trend towards edge and fog computing, the aim of the RECAP simulator is to simulate large scale scenarios in the cloud, fog and edge computing space in order to provide decision and control support for application and data center resource administration. This will be accomplished through the simulation of applications and application subsystems, simulation of infrastructure resources and resource management systems, and experimentation and validation of simulation results. The RECAP simulator and associated models will provide support for understanding and predicting impact on resources, workloads and quality of service (QoS) metrics as well as trade-offs for energy efficiency and cost within cloud, edge and fog computing scenarios, while maintaining the service level agreements (SLAs) of users.
Call centers have been the subject of many simulation studies and the challenges and successes of... more Call centers have been the subject of many simulation studies and the challenges and successes of modelling these environments have been widely published. Call centers have however evolved significantly in the last decade or so, as new communication technologies have become available, customer expectations have increased, and the value of customer experience has been recognized and prioritized. While the single-channel call centers proved complex to analyze and worthy of the advanced analytical power of simulation, the modern multi-channel connection centers bring new levels of complexity to managerial decision making. This paper presents research into the modelling challenges posed by these evolving environments and illustrates how simulation is now more beneficial than ever to organizations aiming to understand and quantify the impact of change in their customer support business.
Outsourcing is becoming more important in the world economy and is a business approach that is in... more Outsourcing is becoming more important in the world economy and is a business approach that is increasing worldwide. As a consequence of this trend, complex supply chains have been created where suppliers can be located throughout the world, with companies who outsource moving increasingly towards multiple suppliers and short-term contracts. Before establishing these contracts, buyers generally issue a request for quotation (RFQ) to a number of potential suppliers who are capable of delivering a specific product(s)/service(s). In responding to these RFQs, suppliers must cost their quotation and respond to the buyer within an agreed timeframe. This can be difficult as the timeframe can be relatively short and many of these contracts contain operational details. This paper presents work carried out on developing an application that aids suppliers in the costing of their contracts. This application is web-based, and utilizes a hybrid simulation and animation (S&A) approach in its implementation.
Across the European Economic Area more goods are being transported over longer distances more fre... more Across the European Economic Area more goods are being transported over longer distances more frequently than ever before. As a result, Greenhouse Gas (GHG) emissions from transport increased overall by 24% between 1990 and 2003 for the 32 countries in the EEA, with emissions from the transport sector in Ireland growing by 130% in the same period. With incoming Kyoto regulations, and opinion resistant to heavy freight traffic, efficient freight transport has become growing concern. This paper will document the tools already used in environmental Supply Chain (SC) analysis and propose the use of Discrete Event Simulation (DES) as a Decision Support System (DSS) to aid decision makers choose the most environmentally friendly SC design.
Objectives & Background The average age of patients occupying the ED in Beaumont ED is seen t... more Objectives & Background The average age of patients occupying the ED in Beaumont ED is seen to be rising and this fact coupled with an aging population points to potential future demand pressures on ED departments. This research looks at the changing age profile of patients that attend the ED and the relationship between age and waiting time or Patient Experience Time (PET) in the ED. This research is part of a wider research project looking to simulate patient flows through the ED. Methods We analysed a 10 year dataset from the ED at Beaumont Hospital to study trends in average patient age and PETs. We then applied linear regression to the 2013 data, (60,000 patient visits to the ED), to examine the relationship between age and PET. Three separate models were developed with PET, time from admission to first medical and time from bed request to being admitted to hospital as the respective dependent variables. These models also controlled for triage type, patient admitted (Yes/No), number in ED and other factors. Results The average age of ED patients has risen from 43.8 years in 2005 to 48.2 years in 2014 (Figure 1). These older patients have a greater likelihood of admission and in addition experience longer waiting times in ED (See Figures 2 and 3). Using a regression analysis, age was seen to contribute an extra half an hour in PET per 10 year increase. Age had, in contrast, a negative effect on time to first medical with lower waiting times for older age groups. In the final model, predicting the patient time from bed request to being admitted to hospital, age emerged as the most significant factor, with older patients experiencing significantly longer waits. Figure 4 demonstrates these findings, in particular the significant proportion of PET for older patients due to bed requests. Conclusion Age has a significant effect on patient experience time in the ED. The time to first medical care is mainly driven by triage category, but even controlling for this, older people receive care faster. However, subsequently older patients spend longer in the ED and this is due to longer waits for older patients for a hospital bed. The result is an ED populated with elderly boarders. With an ageing national population in Ireland this research emphasises a need to plan for the future healthcare of elderly patients within and beyond acute hospitals. Figure 1 Average Age of Beaumont ED Attendees. Figure 2 Age profile of Beaumont ED Patients (Admitted and Discharged). Figure 3 Average Patient Experience Time per Age Band for Admitted and Discharged Patients. Figure 4 Waiting Times by Age Band (2014).
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