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Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Understanding The Dynamic Behaviour Of Three Echelon Retail Supply Chain Disruptions, John Crowe, Mohammed Mesabbah, Amr Arisha Jan 2015

Understanding The Dynamic Behaviour Of Three Echelon Retail Supply Chain Disruptions, John Crowe, Mohammed Mesabbah, Amr Arisha

Conference papers

It is often taken for granted that the right products will be available to buy in retail outlets 7 days a week, 52 weeks a year. Challenges in achieving this continued on-shelf availability range from recession hit demand patterns to cost reduction driven strategies. Irish government initiatives to brand the country as a sustainable, reliable provider of food retail supply chains has resulted in increased importance on decision maker accuracy. The vulnerability of retail supply chain’s (RSC) to disruption is another catalyst in the complexity of the decision making process and a more robust understanding of disruption behavior is ...


Towards Operations Excellence: Optimising Staff Scheduling For New Emergency Department, Amr Arisha, Waleed Abo Hamad Jun 2013

Towards Operations Excellence: Optimising Staff Scheduling For New Emergency Department, Amr Arisha, Waleed Abo Hamad

Conference papers

This paper presents a case study of an Emergency Department of a public hospital in Dublin, and uses an integrated approach to determine optimal staffing levels to meet the challenges of its dynamic patient demand levels. A comprehensive stochastic model is developed to incorporate patients care pathways and the resources required along their treatment journeys. Analytical Hierarchical Process is utilised to enable decision makers to set their preferences for the facility’s strategic objectives. Evolutionary algorithms are applied to optimise staff schedules. The resulted optimized schedules maintains continuity of care delivery for patients while ensuring a balanced equilibrium among available ...


Sustainable Purchasing Practices: An Investigation Into Current Industry Awareness And Practice, Frank Palisi, Kathryne Newton, Edward Sweeney Feb 2013

Sustainable Purchasing Practices: An Investigation Into Current Industry Awareness And Practice, Frank Palisi, Kathryne Newton, Edward Sweeney

Conference papers

This research study illustrates the importance of sustainable purchasing practices for organizations in the U.S. distribution industry and answers several important questions: what is the current awareness of U.S. organizations regarding sustainable purchasing practices; to what extent are U.S. organizations evaluating, selecting, and retaining suppliers based upon sustainable purchasing practices; and to what extent are sustainable purchasing practices being implemented by the U.S. organizations under study? With an ever increasing global economy, is it critically important for organizations to put in place sustainability practices; the biggest impact organizations can make is often in an organization’s ...


A Simulation-Based Decision Support System To Model Complex Demand Driven Heathcare Facilities, Amr Arisha, Michael Thorwarth Dec 2012

A Simulation-Based Decision Support System To Model Complex Demand Driven Heathcare Facilities, Amr Arisha, Michael Thorwarth

Conference papers

Simulating healthcare processes is a sophisticated endeavor. Treatment processes and patient arrival patterns differ significantly in their statistical attributes and implicate a high degree of variability. In addition, there are several types of interconnected processes of medical staff involved that accompany a patient’s journey through the healthcare facility. Replicating this behavior with process flow models in a discrete event simulation model is highly complex and therefore difficult to create while maintaining a high degree of precision. A framework is thus introduced which delivers an algorithm that allows to implement Multiple Participant Pathway Modeling (MPPM) under the consideration of Flexible ...


Multi-Citeria Framework For An Emergency Department In An Irish Hospital, Waleed Abo Hamad, Amr Arisha Dec 2012

Multi-Citeria Framework For An Emergency Department In An Irish Hospital, Waleed Abo Hamad, Amr Arisha

Conference papers

Health research is one of these priorities in every economy and through this research an emphasis will be put on translational research in the context of more sustainable and efficient healthcare system (translation of operations management practices to clinical applications). Healthcare systems in general and Emergency Departments in particular around the world are facing enormous challenges in meeting the increasingly conflicting objectives of providing wide accessibility and efficiency while delivering high quality and prompt services. The proposed framework integrates simulation modeling, balanced scorecard, and multi-criteria decision analysis aiming to provide a decision support system to emergency department managers. Simulation outputs ...


Capacity Planning For Elderly Care In Ireland Using Simluation Modeling, Mohamed Ragab, Waleed Abo Hamad, Amr Arisha Nov 2012

Capacity Planning For Elderly Care In Ireland Using Simluation Modeling, Mohamed Ragab, Waleed Abo Hamad, Amr Arisha

Conference papers

Global population aging is creating an immense pressure on healthcare facilities making them unable to cope with the growing demand for elderly healthcare services. Current demand-supply gaps result in prolonged waiting times for patients and substantial cost burdens for healthcare systems due to delayed discharges. This paper describes a project aimed at presenting modeling and simulation to address elderly care pathways within the Irish healthcare sector. The management of frail patients admitted to acute hospitals and the introduction of the new intermediate care beds are alternative interventions that healthcare executives are interested in simulating to examine their impact on the ...


A Case Study Investigation On Purchasing Green Transport And Logistics Services, Pietro Evangelista, Maria Huge-Brodin, Karin Isaksson, Edward Sweeney Apr 2012

A Case Study Investigation On Purchasing Green Transport And Logistics Services, Pietro Evangelista, Maria Huge-Brodin, Karin Isaksson, Edward Sweeney

Conference papers

In the context of green supply chain management, green purchasing has received increased attention over the past decade and the strategic importance of introducing green aspects into purchasing practices has been recognised. Despite this growing importance, little has been written in relation to purchasing green transport and logistics services. Considering the strong environmental impact associated with transport and logistics activities, much remains to be learned concerning buyer’s practices when sourcing more sustainable services from third party logistics companies (3PLs). The aim of this paper is to explore practices of buying green transport and logistics services in three different European ...


Simulation-Based Optimisation Model For The Lean Assessment In Sme: A Case Study, Amr Arisha, Amr Mahfouz, John Shea Dec 2011

Simulation-Based Optimisation Model For The Lean Assessment In Sme: A Case Study, Amr Arisha, Amr Mahfouz, John Shea

Conference papers

Due to their space limitation and small production scale, small and medium enterprises (SME) are vulner-able to rapid changes. Lean principles are considered as effective improvement approach to eliminate sys-tem’s waste and inefficiencies. Although much of the academic materials have addressed the lean practic-es into large, global companies, they can still be adjusted to SMEs. Risks are usually associated with lean implementation process due to the drastic required changes in business policies and operations. Simulation can be successfully used to predict the impact of the proposed changes ahead of the implementation which helps to mitigate risks. Integrating simulation with ...


A Review Of Parallel Operation Of Active Power Filters In The Distributed Generation System, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon Sep 2011

A Review Of Parallel Operation Of Active Power Filters In The Distributed Generation System, Shafiuzzaman Khan Khadem, Malabika Basu, Michael Conlon

Conference papers

In this paper a technical review of parallel operation of Active Power Filter (APF) for harmonic power compensation in distributed generation (DG) network has been presented. Controlling methods and connection topologies with their pros and cons are described. Recent improvements in controlling and future trends for the application of APFs in distributed mode are also identified.


The Impact Of 3pl’S Green Initiatives On The Purchasing Of Transport And Logistics Services: An Exploratory Study, Pietro Evangelista, Maria Huge-Brodin, Karin Isaksson, Edward Sweeney Jan 2011

The Impact Of 3pl’S Green Initiatives On The Purchasing Of Transport And Logistics Services: An Exploratory Study, Pietro Evangelista, Maria Huge-Brodin, Karin Isaksson, Edward Sweeney

Conference papers

There is a lack of research investigating the interaction and reciprocal influences between the buyer perspective and the supplier of transport and logistics services. Studies on the buyer perspective analyse the selection criteria to buy 3PL services, while research focused on green 3PL services examine initiatives undertaken by these companies to provide more environmentally sustainable services. The objective of this paper is to fill this void through an explorative case study analysis on the environmental attitude of 3PL companies in order to derive relevant implications for buyer’s behaviour. The results provide useful guidelines to buyers for understanding awareness, initiatives ...


Integrating Balanced Scorecard And Simulation Modelling To Improve Emergency Department Performance In Irish Hospitals, Amr Arisha, Waleed Abo-Hamad, Khaled Ismail Dec 2010

Integrating Balanced Scorecard And Simulation Modelling To Improve Emergency Department Performance In Irish Hospitals, Amr Arisha, Waleed Abo-Hamad, Khaled Ismail

Conference papers

In the healthcare sector, there is a requirement for innovative solutions in managing the high levels of complexity and uncertainty within Emergency Departments (EDs). Simulation modeling is currently seen as a competent means of analyzing EDs, which allows changes effects to be understood and predicted more easily. The Balanced Scorecard (BSC), well-known performance management concept, has become a steering method in approaching new improvement cycles. This paper presents a methodology that integrates BSC and simulation modeling to improve the performance of ED in a University Hospital in North Dublin. BSC design began with understanding patient's needs, ED activities, as ...


Customer Management Analysis Of Irish Plumbing & Heating Distribution System: A Simulation Study, Amr Arisha, Amr Mahfouz, John Crowe, Finbarr Bennett Aug 2010

Customer Management Analysis Of Irish Plumbing & Heating Distribution System: A Simulation Study, Amr Arisha, Amr Mahfouz, John Crowe, Finbarr Bennett

Conference papers

The sudden burst of the property bubble, coupled with current global economic conditions has resulted in a huge decrease in demand for plumbing and heating fixtures in the Irish construction industry. Moreover, inefficient supply chain management policies have imposed further pressures on companies resulting in more system bottlenecks and unnecessary costs. Inventory management is seen as a functional area that can ease such bottlenecks and in turn increase supply chain efficiency, decrease costs and increase customer satisfaction. The challenge is to predict the balance of on-hand inventory and order quantity to optimise customer satisfaction and minimise inventory cost. It is ...


The Analysis Of Rush Orders Risk In Supply Chain: A Simulation Approach, Amr Arisha, Amr Mahfouz Jan 2010

The Analysis Of Rush Orders Risk In Supply Chain: A Simulation Approach, Amr Arisha, Amr Mahfouz

Conference papers

Satisfying customers by delivering demands at agreed time, with competitive prices, and in satisfactory quality level are crucial requirements for supply chain survival. Incident of risks in supply chain often causes sudden disruptions in the processes and consequently leads to customers losing their trust in a company’s competence. Rush orders are considered to be one of the main types of supply chain risks due to their negative impact on the overall performance. Using integrated definition modeling approaches (i.e. IDEF0 & IDEF3) and simulation modeling technique , a comprehensive integrated model has been developed to assess rush order risks and examine ...


Simulation Model To Investigate Flexible Workload Management For Healthcare And Servicescape Environment, Michael Thorwarth, Paul Harper, Amr Arisha Dec 2009

Simulation Model To Investigate Flexible Workload Management For Healthcare And Servicescape Environment, Michael Thorwarth, Paul Harper, Amr Arisha

Conference papers

High demand and poor staffing conditions cause avoidable pressure and stress among healthcare personnel which results in burnout symptoms and unplanned absenteeism which are hidden cost drivers. The work environment within an emergency department is commonly arranged in a flexible workload which is highly dynamic and complex for the outside observer. Using detailed simulation modeling within structured modeling methods, a comprehensive model to characterize the nurses' time utilization in such flexible dynamic workload environment was investigated. The results have been used to derive a generalized analytic expression that describes certain settings that lead to an instable queuing system with serious ...


Enabling Rfid Technology In Irish Hospitals, Khaled Ismail, Amr Arisha Sep 2009

Enabling Rfid Technology In Irish Hospitals, Khaled Ismail, Amr Arisha

Conference papers

Hospitals represent a significant part of healthcare systems and account for no less than 60% of the entire healthcare service in most of developed countries. Therefore, improving service in hospitals is an important element to the process of healthcare reform. Better use of resources, more consistent quality, and a higher service level are the keys to rationalise the huge expenditure in healthcare systems due to higher growth in demand. Even though massive spending has been directed towards hospital improvement in Ireland, services provided in Irish hospitals are ranked relatively low comparing to the other European countries. Growth of population, aging ...


Risk Assessment Model For Emergency Departments In Dublin Hospitals, Michael Thorwarth, Amr Arisha Sep 2009

Risk Assessment Model For Emergency Departments In Dublin Hospitals, Michael Thorwarth, Amr Arisha

Conference papers

The internal dynamics of emergency departments (ED) in Irish hospitals represent complex non-linear stochastic systems with an environment of uncertainty, variability and limited resources. Planning and managing such systems pose overwhelming demands. To improve operations, patient service, resource planning, and real-time reaction to unexpected events, sophisticated tools to efficiently achieve these goals must be applied.

Advanced solution techniques (e.g. simulation and optimisation) have been successfully applied in manufacturing operations to improve the delivery, cost-effectiveness and service quality. Yet, random arrival of patients, limited resources and multitasking are challenges in EDs that add more complexity to this critical area. This ...


Optimisation Methods In Supply Chain Applications: A Review, Amr Arisha, Waleed Abo Hamad Sep 2009

Optimisation Methods In Supply Chain Applications: A Review, Amr Arisha, Waleed Abo Hamad

Conference papers

The competitiveness and dynamic nature of today’s marketplace is due to rapid advances in information technology, short product life cycles and the continuing trend in global outsourcing. Managing the resulting supply chain networks effectively is a complex and challenging task which is imputable to high level of uncertainty in supply-demand, conflict objectives, vagueness of information, numerous decision variables and constraints. With such level of complexity in the environment, supply chain optimisation has a potential to make a significant contribution to resolve the challenges. In this paper, a literature review – based on more than one hundred peer-reviewed articles – of state-of-the-art ...


Learning Without Default: A Study Of One-Class Classification And The Low-Default Portfolio Problem, Kenneth Kennedy, Brian Mac Namee, Sarah Jane Delany Aug 2009

Learning Without Default: A Study Of One-Class Classification And The Low-Default Portfolio Problem, Kenneth Kennedy, Brian Mac Namee, Sarah Jane Delany

Conference papers

This paper asks at what level of class imbalance one-class classifiers outperform two-class classifiers in credit scoring problems in which class imbalance, referred to as the low-default portfolio problem, is a serious issue. The question is answered by comparing the performance of a variety of one-class and two-class classifiers on a selection of credit scoring datasets as the class imbalance is manipulated. We also include random oversampling as this is one of the most common approaches to addressing class imbalance. This study analyses the suitability and performance of recognised two-class classifiers and one-class classifiers. Based on our study we conclude ...


Process Modelling Support For The Conceptual Modelling Phase Of A Simulation Project, Cathal Heavey, John Ryan Dec 2006

Process Modelling Support For The Conceptual Modelling Phase Of A Simulation Project, Cathal Heavey, John Ryan

Conference papers

While many developments have taken place around supporting
the model coding task of simulation, there are few tools
available to assist in the conceptual modelling phase. Several
authors have reported the advantages of using process
modelling tools in the early phases of a simulation project.
This paper provides an overview of process modelling tools
in relation to their support for simulation, categorizing the
tools into formal method and descriptive methods. A conclusion
from this review is that none of the tools available
adequately support the requirements gathering phase of
simulation. This is not surprising as none of the process
modelling ...


Requirements Gathering For Simulation, John Ryan, Cathal Heavey Jan 2006

Requirements Gathering For Simulation, John Ryan, Cathal Heavey

Conference papers

This paper discusses the current shortfalls in support for the pre-coding phases of a discrete event simulation project. The paper then presents a process modelling technique, Simulation Activity Diagrams (SADs), developed to specifically support the initial requirements gathering phases of a simulation project. The paper concludes with an outline of proposed future developments to the modelling technique.


Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young Jan 2005

Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young

Conference papers

Semiconductor manufacturing is one of the most complex industries in terms of technology and manufacturing procedure. The life cycle of a semiconductor facility (FAB) has many phases, in their life cycle including capacity planning, new products introduction, variation of products/technologies, and decline phase. The complexity of the manufacturing and the external forces from markets and technology growth make predicting the effects of changes in the manufacturing system problematic. Simulation, if used correctly, is a powerful hands-on tool which may be used to give a better insight of the effect of engineering/management decisions on the performance of the manufacturing ...


Evaluating The Impact Of Production Scheduling On Tool Performance, Amr Arisha, Paul Young Jan 2005

Evaluating The Impact Of Production Scheduling On Tool Performance, Amr Arisha, Paul Young

Conference papers

Scheduling of a semiconductor manufacturing facility is one of the most complex tasks encountered. Confronted with a high technology product market, semiconductor manufacturing is increasingly more dynamic and competitive in the introduction of new products in shorter time intervals. Simulation provides an effective decision support tool in scheduling of semiconductor manufacturing. Simulation model was developed as a risk assessment tool for one of the implant process area. The model examines the impact of production schedule on tool performance by testing different production scenarios. Production ramping, local buffer capacity, product sequence and product mix seem to be influential factors of the ...


Intelligent Simulation-Based Lot Scheduling Of Photolithography Toolsets In A Wafer Fabrication Facility, Amr Arisha, Paul Young Dec 2004

Intelligent Simulation-Based Lot Scheduling Of Photolithography Toolsets In A Wafer Fabrication Facility, Amr Arisha, Paul Young

Conference papers

Scheduling of a semiconductor manufacturing facility is one of the most complex tasks encountered. Confronted with a high technology product market, semiconductor manufacturing is increasingly more dynamic and competitive in the introduction of new products in shorter time intervals. Photolithography, being one of the processes repeated often, is a fabrication bottleneck. Lot scheduling within photolithography is a challenging activity where substantial improvements in factory performance can be made. The proposed scheduling methodology integrates two common approaches, simulation and artificial intelligence. Using detailed simulation modeling within a structured modeling method, a comprehensive model to characterize the photolithography process was developed. An ...


Applications Of Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young Jan 2004

Applications Of Simulation In Semiconductor Manufacturing Facilities, Amr Arisha, Paul Young

Conference papers

Semiconductor fabrication facilities face many challenges through the many phases of their life cycle including design, build, various production ramps, and many levels of production. Confronted with global competition and rapidly changing technology and customer requirements, there is an increasing demand for rapid solution techniques to improve efficiency in manufacturing. The complexities and forces of both market and the process combine to make the use of simulation crucial at many different planning and control levels. While not a panacea for sustainable performance, simulation provides an effective vehicle for defining the path from competitive concepts to real world solutions and gives ...


Thin-Film Simulation Model For Comparing Production Schedules In A Semiconductor Fabrication Facility, Amr Arisha, Paul Young Jan 2004

Thin-Film Simulation Model For Comparing Production Schedules In A Semiconductor Fabrication Facility, Amr Arisha, Paul Young

Conference papers

Analysis of advanced manufacturing systems in any manufacturing industry requires certain level of knowledge about the system. Flexible manufacturing cells, in particular, are commonly used in most wafer fabrication to provide the ability to change product without requiring the construction of new manufacturing plant. This level of flexibility comes at a significant capital cost and, in order to achieve the maximum potential of each cell, it is essential to characterize and establish the performance of these cells in detail before a new production plan is implemented. Using state-of-the-art computer simulation and a structured modelling methodology a generic model of flexible ...


A Simulation Model To Characterize Photolithography Process Of A Semiconductor Wafer Fabrication, Amr Arisha, Paul Young, Mohie El Baradie Jan 2003

A Simulation Model To Characterize Photolithography Process Of A Semiconductor Wafer Fabrication, Amr Arisha, Paul Young, Mohie El Baradie

Conference papers

The pressures on semiconductor manufacturers due to cost considerations, rapid growth of process technology, quality constraints, feature size reduction, and increasingly complex devices are increasing requiring ever higher efficiency from the manufacturing facilities. The complexity of manufacturing high capacity semiconductor devices means that it is impossible to analyze the process control parameters and the production configurations using traditional analytical models. There is, therefore, an increasing need for effective models of each manufacturing process, characterising and analyzing the process in detail, allowing the effect of changes in the production environment on the process to be predicted. The photolithography process is one ...


Simulation Activity Diagrams, John Ryan, Cathal Heavey Jan 2003

Simulation Activity Diagrams, John Ryan, Cathal Heavey

Conference papers

This paper presents a technique, Simulation Activity Diagrams (SAD), developed to lessen the modelling burden during the initial requirements gathering phases of a simulation project. The technique also allows the capture and visual communication of detailed information, to manufacturing personnel, which may otherwise be lost in detailed programming code.


Evaluation Of Scheduling Strategies On The Performance Of A Flexible Manufacturing Cell:A Simulation Study, Amr Arisha, Paul Young, Mohie El Baradie Jan 2003

Evaluation Of Scheduling Strategies On The Performance Of A Flexible Manufacturing Cell:A Simulation Study, Amr Arisha, Paul Young, Mohie El Baradie

Conference papers

The current trend in semiconductor manufacturing is characterized by expanding product variety, decreasing lead times from order to delivery, exacting standards of quality, and competitive prices. One possible means of achieving this is in the form of increased flexibility. Providing flexibility is typically an expensive proposition so, industrial engineers aim to provide more economic approaches to enable flexible manufacturing cells and related equipment to operate appropriately in an efficient manner. It is essential to characterize these tools in detail before the production plans are finalized. Using state-of-the-art computer simulation, a generic model of photolithography tools has been developed. The model ...


On The Selection Of Simulation Software For Manufacturing Application, Amr Arisha, Mohie El Baradie Aug 2002

On The Selection Of Simulation Software For Manufacturing Application, Amr Arisha, Mohie El Baradie

Conference papers

The growing complexity of manufacturing along with the need for higher efficiency, greater flexibility, better product quality and lower cost urged the use of simulation in manufacturing systems. The number and variety of simulation software packages on the market increased as well. Consequently, the varieties of these packages led to some bewilderment on the part of potential users when faced the selection process. The present article addresses an overview of material addressed in journals, conferences, and textbooks on the selection of appropriate simulation software. It also suggests a classification of main criteria to be considered in evaluating simulation software packages ...


Flow Shop Scheduling Problem: A Computational Study, Amr Arisha, Paul Young, Mohie El Baradie Jan 2002

Flow Shop Scheduling Problem: A Computational Study, Amr Arisha, Paul Young, Mohie El Baradie

Conference papers

A computational study has been developed to obtain optimal / near optimal solution for the flow shop scheduling problem with make-span minimization as the primary criterion and the minimization of either the mean completion time, total waiting time or total idle time as the secondary criterion. The objective is to determine a sequence of operations in which to process ‘n’ jobs on ‘m’ machines in same order (flow shop environment) where skipping is allowed. The Simulation approach for deterministic and stochastic flow shop scheduling has been developed. It reads and manipulates data for 500 jobs on 500 machines. Different factorial experiments ...