Publications

Abstract:
Summer of Simulation 50 Years of Seminal Computer Simulation Research.

 

Abstract:
Workforce predictive risk modelling: development of a model to identify general practices at risk of a supply-demand imbalance.

OBJECTIVE: This study aimed to develop a risk prediction model identifying general practices at risk of workforce supply-demand imbalance. DESIGN: This is a secondary analysis of routine data on general practice workforce, patient experience and registered populations (2012 to 2016), combined with a census of general practitioners' (GPs') career intentions (2016). SETTING/PARTICIPANTS: a hybrid approach was used to develop a model to predict workforce supply-demand imbalance based on practice factors using historical data (2012-2016) on all general practices in England (with over 1000 registered patients n=6398). The model was applied to current data (2016) to explore future risk for practices in South West England (n=368). PRIMARY OUTCOME MEASURE: the primary outcome was a practice being in a state of workforce supply-demand imbalance operationally defined as being in the lowest third nationally of access scores according to the General Practice Patient Survey and the highest third nationally according to list size per full-time equivalent GP (weighted to the demographic distribution of registered patients and adjusted for deprivation). RESULTS: Based on historical data, the predictive model had fair to good discriminatory ability to predict which practices faced supply-demand imbalance (area under receiver operating characteristic curve=0.755). Predictions using current data suggested that, on average, practices at highest risk of future supply-demand imbalance are currently characterised by having larger patient lists, employing more nurses, serving more deprived and younger populations, and having considerably worse patient experience ratings when compared with other practices. Incorporating findings from a survey of GP's career intentions made little difference to predictions of future supply-demand risk status when compared with expected future workforce projections based only on routinely available data on GPs' gender and age. CONCLUSIONS: it is possible to make reasonable predictions of an individual general practice's future risk of undersupply of GP workforce with respect to its patient population. However, the predictions are inherently limited by the data available. 

Abstract:
Developing a Smart Operational Research with Hybrid Practice Theories.

The growth of technology-rich data-driven decision environments is seen by some as a challenge to the future relevance of Operational Research. Extant research remains unspecific about the distinct contribution that Operational Research can make in environments that are influenced by big data, data science and analytics. This paper explores the possibility that these environments hold the potential for a new integrative Operational Research offering, which we conceptualise as Smart Operational Research. In developing this proposal, we combine automated co-occurrence analysis of a corpus of literature with human-driven data interpretation to identify instantiations of hybrid decision-making. We then bring theory and practice together to outline the Smart Operational Research framework with the overall aim to enhance actionable insight and positive results for Operational Research practitioners. 

Abstract:
Hybrid simulation modelling in operational research: a state-of-the-art review.

Hybrid simulation (defined as a modelling approach that combines two or more of the following methods: discrete-event simulation, system dynamics, and agent-based simulation)has experienced near-exponential growth in popularity in the past two decades. However, a large proportion of the academic literature on hybrid simulation is found in computer science and engineering journals. Given the importance of this emerging area and its relevance to operational research, this paper provides a review of the topic from an OR perspective. The results of a review of the hybrid simulation literature are presented, using a novel framework based on the simulation lifecycle that will be useful for future modellers and authors alike. Promising areas for future research are identified: these include the development of new methods for conceptual modelling and for model validation. Currently the main application areas are healthcare, supply chain management and manufacturing, and the majority of published models combine discrete-event simulation and system dynamics. 

Abstract:
The Value Paradox of Problem Structuring Methods.

The use of problem structuring method (PSM) interventions leads to outcomes unique to the circumstances of the problem context. Given the singular nature of these outcomes, a consultant attempting to sell a PSM intervention will struggle to articulate value to clients in terms that are commercially meaningful prior to the intervention being enacted. Thus, in order to win a contract to deliver a PSM intervention, the consultant must first resolve this puzzle. We explore this question by (i) reviewing how the value of PSMs has been assessed previously, (ii) setting out a suitable theoretical position to explore the problem and (iii) presenting empirical data from a commercial organization to build our theoretical position. This starts with agreement with Checkland and Scholes that attempting to sell the (financial) value of a PSM intervention a priori is unlikely to ever succeed. Our theoretical development through analysis of empirical data leads to the recognition that the process of selling a PSM intervention is bound to the interposition of the processes of problematization and interessement and the issue of trust. The recognition of a distinction between these and the actual enactment of a PSM intervention leads us to conclude that the process of selling the consulting engagement is entirely associated with the temporal ordering between them. We thus avoid the bind of the original puzzle only by articulating a paradox. To resolve the paradox, we shift analytical focus to the pre-contractual phase of the relationship between a consultant and client and discuss implications of this paradox for soft OR practice. © 2018 the authors. Systems Research and Behavioral Science published by International Federation for Systems Research and John Wiley & Sons Ltd. 

Abstract:
Understanding front-end project workshops with Social Practice Theory.

Stimulated by the growing interest in understanding the actuality of project managing and the need to better understand how front-end project workshops can be efficacious, we aim to turn workshops-as-practice into a meaningful object of inquiry. We operationalise Social Practice Theory by studying the intertwining of materials, skills and meaning in video-recorded micro-episodes in a front-end project workshop. Our findings illustrate how material elements provide sensitive assistance as professional skills are enacted in structuring the project-specific urban development challenge. Our theoretical, methodological and empirical approach makes the characteristic tension of practice between transformation and reproduction accessible for empirical inquiry and theorising from practice, thereby helping to develop project management knowledge that resonates with the experience of the project practitioner. 

Abstract:
Human Agency in Disaster Planning: a Systems Approach.

Current approaches to risk management place insufficient emphasis on the system knowledge available to the assessor, particularly in respect of the dynamic behavior of the system under threat, the role of human agents (HAs), and the knowledge available to those agents. In this article, we address the second of these issues. We are concerned with a class of systems containing HAs playing a variety of roles as significant system elements—as decisionmakers, cognitive agents, or implementers—that is, human activity systems. Within this family of HAS, we focus on safety and mission-critical systems, referring to this subclass as critical human activity systems (CHASs). Identification of the role and contribution of these human elements to a system is a nontrivial problem whether in an engineering context, or, as is the case here, in a wider social and public context. Frequently, they are treated as standing apart from the system in design or policy terms. Regardless of the process of policy definition followed, analysis of the risk and threats to such a CHAS requires a holistic approach, since the effect of undesirable, uninformed, or erroneous actions on the part of the human elements is both potentially significant to the system output and inextricably bound together with the nonhuman elements of the system. We present a procedure for identifying the potential threats and risks emerging from the roles and activity of those HAs, using the 2014 flooding in southwestern England and the Thames Valley as a contemporary example. 

Abstract:
Spontaneous emergence of Community OR: Self-initiating, self-organising problem structuring mediated by social media.

We develop a new constitutive definition of Community OR as a self-initiating, self-organising community actor network emerging spontaneously in response to a triggering event and showing evidence of non-codified OR behaviours leading to action to improve the problem situation. From this new definition we have re-conceptualised Community OR as a construct that can be empirically observed emerging from suitable behavioural data. Social media play an instrumental role, acting as both the source of data and the enabling mechanism through which this form of Community OR occurs. Social media afford new possibilities for community empowerment and participation, with consequences for social enterprise and citizenship. We use Actor Network Theory, and specifically the language of translations, hybrid forums, and Callon's Co-production of Knowledge Model (CKM), as the methodological basis for our definition and analysis. The appearance of hybrid forums as a self-organising response to community needs after an event would seem to be a natural milieu for a range of OR competencies. However, unlike traditional practitioner-led engagements, here the OR practitioner's competency enters in a supportive rather than leading role. We support our argument through the analysis of social media data arising from the community response to a devastating flooding event – the Carlisle floods of December 2015. 

Abstract:
Thinking about complexity in health: a systematic review of the key systems thinking and complexity ideas in health.

RATIONALE, AIMS, AND OBJECTIVES: As the Sustainable Development Goals are rolled out worldwide, development leaders will be looking to the experiences of the past to improve implementation in the future. Systems thinking and complexity science (ST/CS) propose that health and the health system are composed of dynamic actors constantly evolving in response to each other and their context. While offering practical guidance for steering the next development agenda, there is no consensus as to how these important ideas are discussed in relation to health. This systematic review sought to identify and describe some of the key terms, concepts, and methods in recent ST/CS literature. METHOD: Using the search terms "systems thinkin. AND health OR complexity theor. AND health OR complex adaptive system. AND health," we identified 516 relevant full texts out of 3982 titles across the search period (2002-2015). RESULTS: the peak number of articles were published in 2014 (83) with journals specifically focused on medicine/healthcare (265) and particularly the Journal of Evaluation in Clinical Practice (37) representing the largest number by volume. Dynamic/dynamical systems (n = 332), emergence (n = 294), complex adaptive system(s) (n = 270), and interdependent/interconnected (n = 263) were the most common terms with systems dynamic modelling (58) and agent-based modelling (43) as the most common methods. CONCLUSIONS: the review offered several important conclusions. First, while there was no core ST/CS "canon," certain terms appeared frequently across the reviewed texts. Second, even as these ideas are gaining traction in academic and practitioner communities, most are concentrated in a few journals. Finally, articles on ST/CS remain largely theoretical illustrating the need for further study and practical application. Given the challenge posed by the next phase of development, gaining a better understanding of ST/CS ideas and their use may lead to improvements in the implementation and practice of the Sustainable Development Goals. 

Abstract:
Why so Serious? Theorising Playful Model-Driven Group Decision Support with Situated Affectivity.

An integrative approach to theorising behavioural, affective and cognitive processes in model-driven group decision support (GDS) interventions is needed to gain insight into the (micro-)processes by which outcomes are accomplished. This paper proposes that the theoretical lens of situated affectivity, grounded in recent extensions of scaffolded mind models, is suitable to understand the performativity of affective micro-processes in model-driven GDS interventions. An illustrative vignette of a humorous micro-moment in a group decision workshop is presented to reveal the performativity of extended affective scaffolding processes for group decision development. The lens of situated affectivity constitutes a novel approach for the study of interventionist practice in the context of group decision making (and negotiation). An outlook with opportunities for future research is offered to facilitate an integrated approach to the study of cognitive–affective and behavioural micro-processes in model-driven GDS interventions. 

Abstract:
Climate change and cities: problem structuring methods and critical perspectives on low-carbon districts.

Cities around the world have set climate change mitigation targets, yet actions to implement these targets have so far proved inadequate. Better methodology is needed to support this impetus for action. Problem structuring methods (PSMs) enable improvements to be made in wicked problem situations; they appear to have potential to improve climate change mitigation actions but they are difficult to carry out in highly pluralist problem contexts. A case study (STEEP) that applied a PSM to support low-carbon urban energy master planning in three cities is presented. The STEEP methodology was effective in reducing the wickedness of the problem but issues of a lack of clarity on problem ownership and lack of interessement were seen. A reflective boundary critique study found that there was a mismatch between power and interest amongst key stakeholders towards the low-carbon vision. Three key issues identified in the case study were discussed through the lens of critical systems thinking: (i) the need for new competencies, (ii) dealing with wickedness, and (iii) behavioural complexity and discordant reference systems. The paper suggests how these issues might be improved through the application of non-PSM theories which can support the use of PSMs in improving city-level climate change mitigation. 

Abstract:
Widening requirements capture with soft methods: an investigation of hybrid M&S studies in health care.

A simulation study consists of several stages: problem formulation, model implementation, verification and validation, experimentation and output data analysis. The application of multiple techniques in the model implementation stage is referred to as hybrid simulation, which we distinguish in this paper from a hybrid M&S study, the latter referring to studies that apply methods and techniques from disciplines like Operations Research (OR), Systems Engineering and Computer Science to one or more stages of a simulation study. Our paper focuses on the contribution of soft OR methods in the problem formulation stage of a simulation study (and by extension a hybrid M&S study). Soft Systems Methodology (SSM) has, arguably, been the most widely used qualitative approach for eliciting system requirements. In this paper, we present Qualitative System Dynamics (QSD), a soft systems method, as having potential use in the problem formulation stage of a healthcare M&S study. The contribution of this paper is thus twofold: (1) a review of the literature in SSM for healthcare operations management and (2) an examination of QSD as an additional soft OR method, complementing (rather than supplanting) existing approaches, which can further aid the understanding of the system in the problem formulation/conceptual modelling stage of a hybrid M&S study. 

Abstract:
An investigation into modeling and simulation approaches for sustainable operations management.

Modeling and simulation (M&S) studies have been widely used in industry to gain insights into existing or proposed systems of interest. The majority of these studies focus on productivity-related measures to evaluate systems' performance. This paradigm, however, needs to be shifted to cope with the advent of sustainability, as it is increasingly becoming an important issue in the managerial and the organizational agendas. The application of M&S to evaluate the often-competing metrics associated with sustainable operations management (SOM) is likely to be a challenge. The aim of this review is to investigate the underlying characteristics of SOM that lend towards modeling of production and service systems, and further to present an informed discussion on the suitability of specific modeling techniques in meeting the competing metrics for SOM. The triple bottom line, which is a widely used concept in sustainability and includes environmental, social, and economic aspects, is used as a benchmark for assessing this. Findings from our research suggest that a hybrid (combined) M&S approach could be an appropriate method for SOM analysis; however, it has its challenges. 

Abstract:
Contested Modelling: a Critical Examination of Expert Modelling in Sustainability.

We discuss the role of expert modelling in sustainability using a framework designed to improve the effectiveness of the modelling process. Based on the development of a set of reflective questions that can be used at certain key stages in the lifecycle of projects developing such models, we discuss how using the framework would lead to improvements in the coupling of the process of expert modelling with the process of intervention, which is implied by the existence of the expert modelling project. This questioning pushes the development of a framework beyond considerations of ontology and epistemology into issues of axiology and praxis; extending the notion of contested modelling beyond the narrow scientific sense to a wider social setting. Our framework has been developed through a case study analysis of the effectiveness of four research initiatives that have used expert modelling to address the complexity of intervention in a sustainability context. 

Abstract:
Estimating Project Performance through a System Dynamics Learning Model.

Monitoring of the technical progression of projects is highly difficult, especially for complex projects where the current state may be obscured by the use of traditional project metrics. Late detection of technical problems leads to high resolution costs and delayed delivery of projects. To counter this, we report on the development of a updated technical metrics process designed to help ensure the on-time delivery, to both cost and schedule, of high quality products by a U.K. Systems Engineering Company. Published best practice suggests the necessity of using planned parameter profiles crafted to support technical metrics; but these have proven difficult to create due to the variance in project types and noise within individual project systems. This paper presents research findings relevant to the creation of a model to help set valid planned parameter profiles for a diverse range of system engineering products; and in establishing how to help project users get meaningful use out of these planned parameter profiles. We present a solution using a System Dynamics (SD) model capable of generating suitable planned parameter profiles. The final validated and verified model overlays the idea of a learning “S-curve” abstraction onto a rework cycle system archetype. Once applied in SD this matched the mental models of experienced engineering managers within the company, and triangulates with validated empirical data from within the literature. This has delivered three key benefits in practice: the development of a heuristic for understanding the work flow within projects, as a result of the interaction between a project learning system and defect discovery; the ability to produce morphologically accurate performance baselines for metrics; and an approach for enabling teams to generate benefit from the model via the use of problem structuring methodology. 

Abstract:
Investigating the feasibility of supply chain-centric business models in 3D chocolate printing: a simulation study.

3D chocolate printing provides the technology for manufacturing chocolates layer-by-layer, thus offering customers enhanced product value and personalized consumption experience. As business models in the chocolate industry are closely associated with the profitability of the supply chain constituents, it seems appropriate to investigate the financial viability of these supply-chain centric business models prior to their introduction in the real world. In this paper we present two business models pertaining to the supply chain for 3D printed chocolates; we evaluate the financial viability of these innovative models through the use of computer modelling and simulation. The study is based on the commercialization efforts of a UK based 3D chocolate printing technology provider (Choc Edge). The results of the study indicate that 1) the retailer dominant supply chain model is a potentially disruptive business model innovations that are enabled by the 3D food printing technology, and as such, may pose a challenge to traditional high end chocolate products; 2) the manufacturer dominant model helps manufacturers gain more profits while retailer profits tend to be stagnant. 

Abstract:
Planning for 5G: a Problem Structuring Approach for Survival in the Telecoms Industry.

This paper examines the application of systemic problem structuring methods to the development of a research strategy in response to the challenges of fifth generation (5G). The paper proposes a methodology for strategic decision making. The key stakeholders, objectives, technologies, and boundaries from existing literature are identified and problem structuring based on hierarchical process modeling is used to explore the dependency of certain features of 5G on specific technologies, giving an indication of the importance of certain technologies over others and thus insight into where to place research effort. The hard technical challenges of 5G are discussed and equally the importance of the soft social and business challenges explored. For context, we explain how 5G will provide a platform for innovations and discuss how new and existing businesses may use this to their advantage. Problem structuring is used to explore how the challenges and opportunities of future wireless systems are related to the process of developing new business models. 

Abstract:
Revisiting Jevons' Paradox with System Dynamics: Systemic Causes and Potential Cures.

This article examines the dynamic relationship between the consumption of goods and services, technological efficiency, and associated resource use, as described by the theory of Jevons' Paradox (JP). A theory is presented about what causes JP, in which resource efficiency savings are eventually overtaken by increases in consumption to produce a net increase in resource use and therefore environmental impacts. An application of the theory was carried out using system dynamics, modeling carbon dioxide equivalent (CO2-eq) emissions from private road transport in the UK between 1970 and 2010. The model results indicate the approximate impact of JP within the historical period: a rise in travel consumption of approximately one half and a rise in CO2-eq emissions of approximately one third. The model was used to estimate whether the European Union (EU) goal of a 40% drop in CO2-eq emissions by 2030 is achievable in the road transport sector, by adding interventions, and the results indicate that higher increases in fleet efficiency than are currently forecast, costlier travel, and a reduction in travel consumption would all be required. The theory and model presented in this article highlight the need to implement a system of interventions that can influence the strength and direction of each of the feedback loops within the system being intervened with, if CO2-eq emissions are to be more reliably reduced than they are at present. Further, because the system is constantly evolving, intervening with it requires a responsive, holistic approach, while maintaining focus on a long-term goal. 

Abstract:
Sustainability as a ‘super-wicked’ problem; opportunities and limits for engineering methodology.

Characterizing sustainability as a ‘super-wicked’ problem alerts us to issues beyond where current thinking about problem structuring enables engineers to deal with the merely wicked. Time is running out, no one authority is in control, we are the cause of the problem anyway, and we inherently discount the future in our everyday decision-making. When these are added to the usual definitions of wicked and messy problems, which only now are we addressing in engineering education, what are the potential limits and opportunities for the methodology of engineering in sustainability? Some modest extrapolations are discussed, based on the results from a recent research project in addressing energy planning in a city development zone. An analysis from another case study is also presented, which provides some triangulation of the ideas developed in this article. 

Abstract:
Understanding behaviour in problem structuring methods interventions with activity theory.

This article argues that OR interventions, particularly problem structuring methods (PSM), are complex events that cannot be understood by conventional methods alone. In this paper an alternative approach is introduced, where the units of analysis are the activity systems constituted by and constitutive of PSM interventions. The paper outlines the main theoretical and methodological concerns that need to be appreciated in studying PSM interventions. The paper then explores activity theory as an approach to study them. A case study describing the use of this approach is provided. 

Abstract:
Simulation for Sustainable Healthcare (special issue guest editorial).

This is the editorial for my special issue 

Abstract:
The Internet-of-Things: Shaping the new Internet Space (special issue guest editorial).

Note this is the editorial for my special issue 

Abstract:
A game-based approach towards facilitating decision making for perishable products: an example of blood supply chain.

Supply chains for perishable items consist of products with a fixed shelf life and limited production/collection; managing them requires competent decision-making. With the objective of placing the learners in the position of decision-makers, we propose the Blood Supply Chain Game which simulates the supply chain of blood units from donors to patients based on a real case study modeling the UK blood supply chain. The Excel-based game is an abstraction of the technical complex simulation model providing a more appropriate learning environment. This paper presents the game's background, its mathematical formulations, example teaching scenarios and the learners' evaluation. The game aims to translate qualitative aspects of a sensitive supply chain into quantitative economic consequences by presenting a process analysis and suggesting solutions for the patient's benefit in a cost effective manner, trying to synchronize blood demand and supply and maximize the value of the whole supply chain. This innovative approach will be instructive for students and healthcare service professionals. © 2014 Elsevier Ltd. All rights reserved. 

Abstract:
Exploring the modelling and simulation knowledge base through journal co-citation analysis.

Co-citation analysis is a form of content analysis that can be applied in the context of scholarly publications with the purpose of identifying prominent articles, authors and journals being referenced to by the citing authors. It identifies co-cited references that occur in the reference list of two or more citing articles, with the resultant co-citation network providing insights into the constituents of a knowledge domain (e.g. significant authors and papers). The contribution of the paper is twofold; (a) the demonstration of the added value of using co-citation analysis, and for this purpose the underlying dataset that is chosen is the peer-reviewed publication of the Society for Modeling and Simulation International (SCS)-SIMULATION; (b) the year 2012 being the 60th anniversary of the SCS, the authors hope that this paper will lead to further acknowledgement and appreciation of the Society in charting the growth of Modeling and Simulation (M&S) as a discipline. © 2013 Akadémiai Kiadó, Budapest, Hungary. 

Abstract:
The non-codified use of problem structuring methods and the need for a generic constitutive definition.

When we use a PSM what is it we are actually doing? an answer to this question would enable the PSM community to considerably enlarge the available source of case studies by the inclusion of examples of non-codified PSM use. We start from Checkland's own proposal for a "constitutive definition" of SSM, which originated from trying to answer the question of knowing when a claim of SSM use was legitimate. By extending this idea to a generic constitutive definition for all PSMs leads us to propose a self-consistent labelling schema for observed phenomena arising from PSMs in action. This consists of a set of testable propositions, which, through observation of putative PSM use, can be used to assess validity of claims of PSM use. Such evidential support for the propositions as may be found in putative PSM use can then make it back into a broader axiomatic formulation of PSMs through the use of a set-Theoretic approach, which enables our method to scale to large data sets. The theoretical underpinning to our work is in causal realism and middle range theory. We illustrate our approach through the analysis of three case studies drawn from engineering organisations, a rich source of possible non-codified PSM use. The combination of a method for judging cases of non-codified PSM use, sound theoretical underpinning, and scalability to large data sets, we believe leads to a demystification of PSMs and should encourage their wider use. © 2014 Elsevier B.V. All rights reserved. 

Abstract:
A view of Systems Practice: Enabling quality in design.

The purpose of the study was to gain a greater understanding of the use of Systems Practice among engineers working in the Rolls-Royce Defence Sector at its Bristol site and develop hypotheses about its use. This study is part of a larger project to investigate and improve the use and embedding of Systems Practice among engineers at the site. The current situation was studied using a combination of grounded theory and system dynamics, supported by the use of a computer-aided qualitative data analysis software (CAQDAS) package. The results from this work show that Systems Practice is valued as a way of enabling quality in design but engineers find it challenging to adopt because of (i) lack of stakeholder appreciation of its value, (ii) their lack of experience with Systems Engineering, and (iii) logistical issues with its application. This work will be followed by group model building sessions to further develop the findings by identifying interventions to create and assess improvement in Systems Practice, in particular finding errors earlier in the design lifecycle. © 2012 Wiley Periodicals, Inc. 

Abstract:
Analysing trade-offs in container loading: Combining load plan construction heuristics with agent-based simulation.

In this paper we describe two operations research techniques, cutting and packing optimisation (CPO) and simulation, and present a multi-methodology approach for analysing the trade-offs between loading efficiency and various important practical considerations in relation to the cargo, such as its stability, fragility or possible cross-contamination between different types of items over time. The feasibility of this approach is demonstrated by considering a situation where the items to be loaded have differing degrees of perishability and where badly deteriorated items can affect those in their immediate vicinity (e.g. through the spread of mould). Our approach uses the output of the CPO algorithms to create agents that simulate the spread of mould through proximity-based interactions between the agents. The results show the trade-offs involved in container utilisation and the propagation of mould, without evidence of any correlation between them. The contribution of this research is the methodology and the feasibility study. © 2013 International Federation of Operational Research Societies. 

Abstract:
Modeling and assessing variability in energy consumption during the use stage of online multimedia services.

In this study, we use an improved, more accurate model to analyze the energy footprint of content downloaded from a major online newspaper by means of various combinations of user devices and access networks. Our results indicate that previous analyses based on average figures for laptops or desktop personal computers predict national and global energy consumption values that are unrealistically high. Additionally, we identify the components that contribute most of the total energy consumption during the use stage of the life cycle of digital services. We find that, depending on the type of user device and access network employed, the data center where the news content originates consumes between 4% and 48% of the total energy consumption when news articles are read and between 2% and 11% when video content is viewed. Similarly, we find that user devices consume between 7% and 90% and 0.7% and 78% for articles and video content, respectively, depending on the type of user device and access network that is employed. Though increasing awareness of the energy consumption by data centers is justified, an analysis of our results shows that for individual users of the online newspaper we studied, energy use by user devices and the third-generation (3G) mobile network are usually bigger contributors to the service footprint than the datacenters. Analysis of our results also shows that data transfer of video content has a significant energy use on the 3G mobile network, but less so elsewhere. Hence, a strategy of reducing the resolution of video would reduce the energy footprint for individual users who are using mobile devices to access content by the 3G network. © 2013 by Yale University. 

Abstract:
System behaviour modelling for demand response provision in a smart grid.

While pilot projects in the smart grid domain have abounded through public and private efforts, there is still uncertainty in identifying effective business models for the smart grid. In this paper we take the view of a new entrant in this market acting as a third party provider of demand response. New entrants are a key player in emerging technological domains but simulation and policy analysis from this perspective have not been forthcoming. We present a novel approach for evaluating business models within a regulatory context and avoid committing to specific technical solutions but instead embark on a parameter exploration through simple yet insightful agent-based models. Our simulations analyse the impact of system performance by three key variables; participant population size, household flexibility in terms of the maximum number of DR events allowed and size of load shifting/shedding available. The simulations indicate that benefits of avoided capital investment leads to valuing a participating household at approximately £1800 over a 20 year period. These results show how mandated infrastructure influenced by policy can affect the value proposition of a demand response service and provide a useful reference for system level parameter requirements. With weak business models, policy decisions can be crucial in providing the impetus needed to spur growth in this market. © 2013 Elsevier Ltd. 

Abstract:
The uses of qualitative data in multimethodology: Developing causal loop diagrams during the coding process.

In this research note we describe a method for exploring the creation of causal loop diagrams (CLDs) from the coding trees developed through a grounded theory approach and using computer aided qualitative data analysis software (CAQDAS). The theoretical background to the approach is multimethodology, in line with Minger's description of paradigm crossing and is appropriately situated within the Appreciate and Analyse phases of PSM intervention. The practical use of this method has been explored and three case studies are presented from the domains of organisational change and entrepreneurial studies. The value of this method is twofold; (i) it has the potential to improve dynamic sensibility in the process of qualitative data analysis, and (ii) it can provide a more rigorous approach to developing CLDs in the formation stage of system dynamics modelling. We propose that the further development of this method requires its implementation within CAQDAS packages so that CLD creation, as a precursor to full system dynamics modelling, is contemporaneous with coding and consistent with a bridging strategy of paradigm crossing. © 2013 Elsevier B.V. All rights reserved. 

Abstract:
Motivations and barriers in using distributed supply chain simulation.

Discrete event simulation (DES) is a technique that is used by analysts to take informed decisions regarding an existing or proposed system of interest. DES models typically represent the processes associated with various business units. However, in the case of supply chains more than one business unit may need to be modelled as different organisations may be responsible for various supply chain operations such as manufacturing, transport and logistics, distribution, warehouse operations, etc. Organisations can be protective about their internal processes and can have concerns regarding data/information security and privacy. Thus it could be argued that creating a single DES supply chain model representing the various inter-organisational processes is usually not an option since this will run counter to organisational privacy. Further, issues such as data transfer, model composability and execution speed may also make a single model approach problematic. A potential solution could be to create several distinct and well-defined DES models, each modelling the processes associated with one specific supply chain business unit, linked together over the internet. We refer to this possible distributed approach as Distributed Supply Chain Simulation (DSCS). Although this approach holds great promise, there are technical barriers in using DSCS. The paper discusses the benefits and barriers of a distributed approach and then, using a healthcare DSCS, the technological feasibility is demonstrated. In conclusion, the paper argues that adopting a standardised approach to DSCS will remove a major barrier to its use. © 2011 International Federation of Operational Research Societies. 

Abstract:
Rethinking health systems strengthening: key systems thinking tools and strategies for transformational change.

While reaching consensus on future plans to address current global health challenges is far from easy, there is broad agreement that reductionist approaches that suggest a limited set of targeted interventions to improve health around the world are inadequate. We argue that a comprehensive systems perspective should guide health practice, education, research and policy. We propose key 'systems thinking' tools and strategies that have the potential for transformational change in health systems. Three overarching themes span these tools and strategies: collaboration across disciplines, sectors and organizations; ongoing, iterative learning; and transformational leadership. The proposed tools and strategies in this paper can be applied, in varying degrees, to every organization within health systems, from families and communities to national ministries of health. While our categorization is necessarily incomplete, this initial effort will provide a valuable contribution to the health systems strengthening debate, as the need for a more systemic, rigorous perspective in health has never been greater. 

Abstract:
SCS: 60 years and counting! a time to reflect on the Society’s scholarly contribution to M&S from the turn of the millennium.

The Society for Modeling and Simulation International (SCS) is celebrating its 60th anniversary this year. Since its inception, the Society has widely disseminated the advancements in the field of modeling and simulation (M&S) through its peer-reviewed journals. In this paper we profile research that has been published in the journal SIMULATION: Transactions of the Society for Modeling and Simulation International from the turn of the millennium to 2010; the objective is to acknowledge the contribution of the authors and their seminal research papers, their respective universities/departments and the geographical diversity of the authors’ affiliations. Yet another objective is to contribute towards the understanding of the overall evolution of the discipline of M&S; this is achieved through the classification of M&S techniques and its frequency of use, analysis of the sectors that have seen the predomination application of M&S and the context of its application. It is expected that this paper will lead to further appreciation of the contribution of the Society in influencing the growth of M&S as a discipline and, indeed, in steering its future direction. © 2012, the Society for Modeling and Simulation International. All rights reserved. 

Abstract:
Service-oriented simulation using web ontology.

Commercial-off-the-Shelf (COTS) Simulation Packages (CSPs) have proved popular in a wider industrial setting. Reuse of Simulation Component (SC) models by collaborating organisations or divisions is restricted, however, by the same semantic issues that restrict the inter-organisation use of other software services. Semantic models, in the form of ontology, utilised by a web-service-based discovery and deployment architecture provide one approach to support simulation model reuse. Semantic interoperation is achieved using domain-grounded SC ontology to identify reusable components and subsequently loaded into a CSP, and locally or remotely executed. The work is based on a health service simulation that addresses the transportation of blood. The ontology-engineering framework and discovery architecture provide a novel approach to inter-organisation simulation, uncovering domain semantics and providing a less intrusive mechanism for component reuse. The resulting web of component models and simulation execution environments present a nascent approach to simulation grids. Copyright © 2012 Inderscience Enterprises Ltd. 

Abstract:
A profile of or research and practice published in the Journal of the Operational Research Society.

In this paper we reflect on the last 10 years of the Journal of the Operational Research Society (JORS). We use metadata and citation analysis to profile OR research and practice published in this prestigious journal. The analysis of the published material includes examining variables such as the most productive authors, the papers having the highest number of citations, the universities and organisations associated with the most publications and their geographic diversity, OR techniques and their application areas, the number of authors per paper, the background of the authors, etc. Moreover, this work includes variables from a previously published study of JORS that profiled research from 1981 to 1999. Therefore, the analysis allows a comparison to be conducted between some of the findings of the two studies. This research has implications for researchers, journal editors and research institutions. © 2010 Operational Research Society Ltd. All rights reserved. 

Abstract:
Exploiting grid computing, desktop grids and cloud computing for escience: Future directions.

Purpose – the purpose of this paper is to examine three different, but related, distributed computing technologies in the context of publicfunded escience research, and to present the author's viewpoint on future directions. Design/methodology/approach the paper takes a critical look at the stateoftheart with regard to three enabling technologies for escience. It forms a set of arguments to support views on the evolution of these technologies in support of the escience applications of the future. Findings Although grid computing has been embraced in publicfunded higher education institutions and research centres as an enabler for projects pertaining to escience, the adoption of desktop grids is low. With the advent of cloud computing and its promise of ondemand provisioning of computing resources, it is expected that the conventional form of grid computing will gradually move towards cloudbased computing. However, cloud computing also brings with it the “payperuse” economic model, and this may act as stimulus for organisations engaged in escience to harvest existing underutilised computation capacity through the deployment of organisationwide desktop grid infrastructures. Conventional grid computing will continue to support future escience applications, although its growth may remain stagnant. Originality/value the paper argues that there will be a gradual shift in the underlying distributed computing technologies that support escience applications of the future. While cloud computing and desktop grid computing will gain in prominence, the growth of traditional clusterbased grid computing may remain dormant. © 2010, Emerald Group Publishing Limited 

Abstract:
Improving decision making in healthcare services through the use of existing simulation modelling tools and new technologies.

Purpose: the purpose of this paper is to investigate the viability of using distributed simulation to execute large and complex healthcare simulation models which help government take informed decisions. Design/methodology/approach: the paper compares the execution time of a standalone healthcare supply chain simulation with its distributed counterpart. Both the standalone and the distributed models are built using a commercial simulation package (CSP). Findings: the results show that the execution time of the standalone healthcare supply chain simulation increases exponentially as the size and complexity of the system being modelled increases. On the other hand, using distributed simulation approach decreases the run time for large and complex models. Research limitations/implications: the distributed approach of executing different parts of a single simulation model over different computers is only viable when the model: can be divided into logical parts and the exchange of information between these parts occurs at constant simulated time intervals; is sufficiently large and complicated, such that executing the model over a single processor is very time consuming. Practical implications: Based on a feasibility study of the UK National Blood Service we demonstrate the effectiveness of distributed simulation and argue that it is a vital technique in healthcare informatics with respect to supporting decision making in large healthcare systems. Originality/value: to the best of the knowledge, this is the first feasibility study in healthcare which shows the outcome of modelling and executing a distributed simulation using unmodified CSPs and a software/middleware for distributed simulation. © Emerald Group Publishing Limited. 

Abstract:
It's unwritten in the Cloud: the technology enablers for realising the promise of Cloud Computing.

Purpose – the purpose of this paper is to evaluate, through arguments, the enabling factors that are expected to facilitate the adoption of Cloud Computing. Design/methodology/approach – the approach is based on the study of the recent developments in ICT and the authors' views and arguments as to how such advancements are expected to lead to an increased adoption of Cloud Computing. Findings – Several ICT areas have to be developed in conjunction for the promise of Cloud Computing to be realised. These include (but are not limited to) the development of parallel programming paradigms and open source software, Cloud access to high performance computing, Green IT, investment in low-cost access-cum-computing devices and hi-speed networks. Originality/value – the paper identifies the current advances in ICT and its expected influence on the adoption of Cloud computing. Furthermore, it lays emphasis on the developing economies and discusses the low-cost technologies and infrastructure investments (including government subsidies) required to provide Cloud-access to the masses. © 2010, Emerald Group Publishing Limited 

Abstract:
Profiling literature in healthcare simulation.

The publications that relate to the application of simulation to healthcare have steadily increased over the years. These publications are scattered amongst various journals that belong to several subject categories, including operational research, health economics and pharmacokinetics. The simulation techniques that are applied to the study of healthcare problems are also various. The aim of this study, therefore, is to review healthcare simulation literature that have been published between 1970 and 2007 in high-quality journals belonging to various subject categories and that report on the application of four simulation techniques, namely, Monte Carlo simulation, discrete-event simulation, system dynamics and agent-based simulation. Arguably, journal impact factor is fundamental in assessing the quality of publications. Thus, the 201 publications selected for review have been queried from the ISI Web of Science bibliographic database of high-impact research journals. Through a review of healthcare simulation literature the following three objectives have been realized: (a) papers have been categorized under the different simulation techniques, and the healthcare problems that each technique is employed to investigate are identified; (b) variables such as authors, article citations, etc. within our dataset of healthcare papers have been profiled; (c) turning point (strategically important) papers and authors have been identified through co-citation analysis of references cited by the papers in our dataset. The above objectives have been realized by devising and then employing a methodology for profiling literature. It is expected that this review paper will help the readers gain a broader understanding of research in healthcare simulation. © 2010 the Society for Modeling and Simulation International. 

Abstract:
Profiling research published in the Journal of Enterprise Information Management (JEIM).

Purpose – the purpose of this paper is to analyse research published in the Journal of Enterprise Information Management (JEIM) in the last ten years (1999-2008). Design/methodology/approach – Employing a profiling approach, the analysis of the 381 JEIM publications includes examining variables such as the most active authors, geographic diversity, authors' backgrounds, co-author analysis, research methods and keyword analysis. Findings – all the findings are in relation to the period of analysis (1999-2008). Research categorised under descriptive, theoretical and conceptual methods is the most dominant research approach followed by JEIM authors. This is followed by case study research. The largest proportion of contributions comes from researchers and practitioners with an information systems (IS) background, followed by those with a background in business and computer science and IT. The keyword analysis suggests that “IS”, “electronic commerce”, “internet”, “logistics”, “supply chain management”, “decision making”, “small to medium-sized enterprises”, “information management”, “outsourcing” and “modelling” are the most frequently investigated keywords. The paper presents and discusses the findings obtained from the citation analysis that determines the impact of the research published in JEIM. Originality/value – the primary value of this paper lies in extending the understanding of the evolution and patterns of IS research. This has been achieved by analysing and synthesising existing JEIM publications. © 2010, Emerald Group Publishing Limited 

Abstract:
Speeding-up the execution of credit risk simulations using desktop grid computing: a case study.

This paper describes a case study that was undertaken at a leading European Investment bank in which desktop grid computing was used to speed-up the execution of Monte Carlo credit risk simulations. The credit risk simulations were modelled using commercial-off-the-shelf simulation packages (CSPs). The CSPs did not incorporate built-in support for desktop grids, and therefore the authors implemented a middleware for desktop grid computing, called WinGrid, and interfaced it with the CSP. The performance results show that WinGrid can speed-up the execution of CSP-based Monte Carlo simulations. However, since WinGrid was installed on non-dedicated PCs, the speed-up achieved varied according to users' PC usage. Finally, the paper presents some lessons learnt from this case study. It is expected that this paper will encourage simulation practitioners and CSP vendors to experiment with desktop grid computing technologies with the objective of speeding-up simulation experimentation. 

Abstract:
Comparing conventional and distributed approaches to simulation in a complex supply-chain health system.

Decision making in modern supply chains can be extremely daunting due to their complex nature. Discrete-event simulation is a technique that can support decision making by providing what-if analysis and evaluation of quantitative data. However, modelling supply chain systems can result in massively large and complicated models that can take a very long time to run even with today's powerful desktop computers. Distributed simulation has been suggested as a possible solution to this problem, by enabling the use of multiple computers to run models. To investigate this claim, this paper presents experiences in implementing a simulation model with a conventional approach and with a distributed approach. This study takes place in a healthcare setting, the supply chain of blood from donor to recipient. The study compares conventional and distributed model execution times of a supply chain model simulated in the simulation package Simul8. The results show that the execution time of the conventional approach increases almost linearly with the size of the system and also the simulation run period. However, the distributed approach to this problem follows a more linear distribution of the execution time in terms of system size and run time and appears to offer a practical alternative. On the basis of this, the paper concludes that distributed simulation can be successfully applied in certain situations. Journal of the Operational Research Society (2009) 60, 43-51. doi:10.1057/palgrave.jors.2602531 Published online 28 November 2007©2009 Operational Research Society Ltd. All rights reserved. 0160-5682/09. 

Abstract:
Facilitating the analysis of a UK national blood service supply chain using distributed simulation.

In an attempt to investigate blood unit ordering policies, researchers have created a discrete-event model of the UK National Blood Service (NBS) supply chain in the Southampton area of the UK. The model has been created using Simul8, a commercial off-the-shelf (COTS) discrete-event simulation package (CSP). However, as more hospitals were added to the model, it was discovered that the length of time needed to perform a single simulation severely increased. It has been claimed that distributed simulation, a technique that uses the resources of many computers to execute a simulation model, can reduce simulation runtime. Further, an emerging standardized approach exists that supports distributed simulation with CSPs. These CSP Interoperability (CSPI) standards are compatible with the IEEE 1516 standard, the High Level Architecture (HLA), the de facto interoperability standard for distributed simulation. To investigate if distributed simulation can reduce the execution time of NBS supply chain simulation, this paper presents experiences of creating a distributed version of the CSP Simul8 according to the CSPI/HLA standards. It shows that the distributed version of the simulation does indeed run faster when the model reaches a certain size. Further, we argue that understanding the relationship of model features is key to performance. This is illustrated by experimentation with two different protocols implementations (using Time Advance Request (TAR) and Next Event Request (NER)). Our contribution is therefore the demonstration that distributed simulation is a useful technique in the timely execution of supply chains of this type and that careful analysis of model features can further increase performance. © 2009 Sage Publications. 

Abstract:
Profiling a decade of Information Systems Frontiers' research.

This article analyses the first 10 years of research published in the Information Systems Frontiers (ISF) from 1999 to 2008. The analysis of the published material includes examining variables such as most productive authors, citation analysis, universities associated with the most publications, geographic diversity, authors' backgrounds and research methods. The keyword analysis suggests that ISF research has evolved from establishing concepts and domain of information systems (IS), technology and management to contemporary issues such as outsourcing, web services and security. The analysis presented in this paper has identified intellectually significant studies that have contributed to the development and accumulation of intellectual wealth of ISF. The analysis has also identified authors published in other journals whose work largely shaped and guided the researchers published in ISF. This research has implications for researchers, journal editors, and research institutions. © 2008 Springer Science+Business Media, LLC. 

Abstract:
Speeding up simulation applications using wingrid.

The vision of grid computing is to make computational power, storage capacity, data and applications available to users as readily as electricity and other utilities.Grid infrastructures and applications have traditionally been geared towards dedicated, centralized, high-performance clusters running on UNIX 'flavour'operating systems (commonly referred to as cluster-based grid computing).This can be contrasted with desktop-based grid computing that refers to the aggregation of non-dedicated, de-centralized, commodity PCs connected through a network and running (mostly) the Microsoft Windows operating system.Large-scale adoption of such Windows-based grid infrastructure may be facilitated via grid enabling existingWindows applications.This paper presents the wingrid approach to grid-enabling existing Windows-based commercial-off-the-shelf simulation packages (CSPs).Through the use of two case studies developed in conjunction with a major automotive company and a leading investment bank, respectively, the contribution of this paper is the demonstration of how experimentation with the CSP Witness (Lanner Group) and the CSP Analytics (SunGard Corporation) can achieve speedup when using WinGrid middleware on both dedicated and non-dedicated grid nodes.It is hoped that this research would facilitate wider acceptance of desktop grid computing among enterprises interested in a low-intervention technological solution to speeding up their existing simulations. © 2009 John Wiley & Sons, Ltd. 

Abstract:
Ontology engineering for simulation component reuse.

Commercial-off-the-shelf(COTS) Simulation Packages (CSP) are widely used in industry primarily due to economic factors associated with developing proprietary software platforms. Regardless of their widespread use, CSPs have yet to operate across organizational boundaries. The limited reuse of CSPs is affected by the same semantic issues that restrict the inter-organizational use of software components and Web services. The current representations of Web components are predominantly syntactic in nature lacking the fundamental semantic underpinning required to support discovery on the emerging Semantic Web. We present new research that partially alleviates the problem of limited semantic interoperability and reuse of simulation components in CSPs. Semantic models, in the form of ontologies, utilized by Web service discovery and deployment architecture provide one approach to support simulation model reuse. Although specific to CSPs this work has wider implications for the simulation community. Copyright © 2009, IGI Global. 

Abstract:
A Comparison of CMB- and HLA-Based Approaches to Type I Interoperability Reference Model Problems for COTS-Based Distributed Simulation.

Commercial off-the-shelf (COTS) simulation packages (CSPs) are software used by many simulation modelers to build and experiment with models of various systems in domains such as manufacturing, health, logistics, and commerce. As part of an ongoing standardization effort, this article introduces the COTS Simulation Package Emulator (CSPE), a proposed benchmark that can be used to investigate asynchronous entity-passing problems as described by the Type I interoperability reference model for COTS-based distributed simulation. To demonstrate its use, two approaches to this form of interoperability are discussed: an implementation based on the Chandy-Misra-Bryant (CMB) conservative algorithm and an implementation based on the High Level Architecture (HLA) Time Advance Request (TAR). It is shown the HLA approach outperforms the CMB approach in almost all cases. The article concludes that the CSPE benchmark is a valid basis from which the most efficient approach to Type I interoperability problems for COTS-based distributed simulation can be discovered. © 2005, Sage Publications. All rights reserved. 

Abstract:
Group Support Systems: experiments with an online system and implications for same-time/different places working.

 

Abstract:
Demystifying facilitation: a new approach to investigating the role of facilitation in group decision support processes.

 

Abstract:
Evaluating How System Health Assessment can Trigger Anticipatory Action for Resilience.

 

Abstract:
A Synthesis of Operational Research for Emergency Planning in Healthcare through the Triple Lens of Technique-Domain-Context.

 

Abstract:
Big Data and Behavior in Operational Research: Towards a “Smart OR”.

 

Abstract:
Operational Research for Healthcare Emergency Planning at a Strategic Level.

 

Abstract:
Smart cities:big data and behavioral operational research.

 

Abstract:
A Case Study of Applying Complexity Leadership Theory in Thales UK.

 

Abstract:
Understanding PSM Interventions Through Sense-Making and the Mangle of Practice Lens.

 

Abstract:
The European research and education networks: Ensuring Europe's leadership in e-science.

 

Abstract:
Leveraging simulation practice in industry through use of desktop grid middleware.

 

Abstract:
Speeding up decision support: Investigating the distributed simulation of a healthcare supply chain.

 

Abstract:
A Hybrid Modelling Approach Using Forecasting and Real-Time Simulation to Prevent Emergency Department Overcrowding.

 

Abstract:
Broadening Participation in Modelling.

 

Abstract:
Hybrid Simulation Development - is it Just Analytics?.

 

Abstract:
Proactive service recovery in emergency departments: a hybrid modelling approach using forecasting and real-time simulation.

 

Abstract:
RH-RT: a data analytics framework for reducing wait time at emergency departments and centres for urgent care.

 

Abstract:
Symbiotic simulation system: Hybrid systems model meets big data analytics.

 

Abstract:
Investigating the use of real-time data in nudging patients' Emergency Department (ED) attendance behaviour.

 

Abstract:
Hybrid simulation studies and Hybrid Simulation systems: Definitions, challenges, and benefits.