187 research outputs found
A grid computing framework for commercial simulation packages
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.An increased need for collaborative research among different organizations, together with continuing advances in communication technology and computer hardware, has facilitated the development of distributed systems that can provide users non-trivial access to geographically dispersed computing resources (processors, storage, applications, data, instruments, etc.) that are administered in multiple computer domains. The term grid computing or grids is popularly used to refer to such distributed systems. A broader definition of grid computing includes the use of computing resources within an organization for running organization-specific applications. This research is in the context of using grid computing within an enterprise to maximize the use of available hardware and software resources for processing enterprise applications. Large scale scientific simulations have traditionally been the primary benefactor of grid computing. The application of this technology to simulation in industry has, however, been negligible. This research investigates how grid technology can be effectively exploited by simulation practitioners using Windows-based commercially available simulation packages to model simulations in industry. These packages are commonly referred to as Commercial Off-The-Shelf (COTS) Simulation Packages (CSPs). The study identifies several higher level grid services that could be potentially used to support the practise of simulation in industry. It proposes a grid computing framework to investigate these services in the context of CSP-based simulations. This framework is called the CSP-Grid Computing (CSP-GC) Framework. Each identified higher level grid service in this framework is referred to as a CSP-specific service. A total of six case studies are presented to experimentally evaluate how grid computing technologies can be used together with unmodified simulation packages to support some of the CSP-specific services. The contribution of this thesis is the CSP-GC framework that identifies how simulation practise in industry may benefit from the use of grid technology. A further contribution is the recognition of specific grid computing software (grid middleware) that can possibly be used together with existing CSPs to provide grid support. With its focus on end-users and end-user tools, it is intended that this research will encourage wider adoption of grid computing in the workplace and that simulation users will derive benefit from using this technology
Investigating distributed simulation with COTS simulation packages: Experiences with Simul8 and the HLA
No full textCommercial-off-the-shelf simulation packages (CSPs) are used widely in industry. Several research groups are currently working towards the creation of distributed simulation with these CSPs. The motivations to do this are various and are largely unproven as there are very few good examples of this kind of distributed simulation in practice. Our goal is therefore to create a distributed simulation environment using CSPs that will allow end users to make their own decisions as to whether this technology will be useful. This paper presents continuing research in creating such an environment using the CSP Simul8 and the High Level Architecture, the IEEE 1516 standard for distributed simulation. The scope of this paper is limited to the CSPI-PDG Type I Interoperability Reference Model
Facilitating the analysis of a UK national blood service supply chain using distributed simulation
No full textIn 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 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, the defacto 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
sj-docx-1-sim-10.1177_00375497221139282 – Supplemental material for Simulation modelling of hospital outpatient Department: a review of the literature and bibliometric analysis
No full textSupplemental material, sj-docx-1-sim-10.1177_00375497221139282 for Simulation modelling of hospital outpatient Department: a review of the literature and bibliometric analysis by Aby M Philip, Shanmugam Prasannavenkatesan and Navonil Mustafee in SIMULATION</p
Hybrid Modelling and Simulation (M&S): Driving Innovation in the Theory and Practice of M&S
No full textThis is the author accepted manuscript. The final version is available from IEEE via the DOI in this recordHybrid Simulation (HS) is the application of two or more simulation techniques (e.g., ABS, DES, SD) in a
single M&S study. Distinct from HS, Hybrid Modelling (HM) is defined as the combined application of
simulation approaches (including HS) with methods and techniques from the broader OR/MS literature and
also across disciplines. In this paper, we expand on the unified conceptual representation and classification
of hybrid M&S, which includes both HS (Model Types A-C), hybrid OR/MS models (D, D.1) and crossdisciplinary hybrid models (Type E), and assess their innovation potential. We argue that model types
associated with HM (D, D.1, E), with its focus on OR/MS and cross-disciplinary research, are particularly
well-placed in driving innovation in the theory and practice of M&S. Application of these innovative HM
methodologies will lead to innovation in the application space as new approaches in stakeholder
engagement, conceptual modelling, system representation, V&V, experimentation, etc. are identified
Ten years of the hybrid simulation track: reflections and vision for the future
No full textThe Hybrid Simulation (HS) track was included in the Winter Simulation Conference (WSC) proceedings as a full conference track for the first time in 2014. A decade has passed since that inaugural track, and HS research and practice has seen impressive advancements during this time. This paper, based on a high-level review of the published works in the last ten years of the HS track, reflects on its successes and challenges and sets the scene for the future of the field. The paper is authored by the HS track organizers, both past and present, who report on the track's history, the nature of HS applications, the modeling tools and software available, as well as implementation challenges and the users' perspective. Finally, the paper discusses the future of HS
Hybrid Simulation Modelling in Operational Research: A State-of-the-art Review
No full textThis is the final version. Available on open access from Elsevier via the DOI in this recordHybrid 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
Distributed simulation with COTS simulation packages: A case study in health care supply chain simulation
No full textThe UK National Blood Service (NBS) is a public funded body that is responsible for distributing blood and asso-ciated products. A discrete-event simulation of the NBS supply chain in the Southampton area has been built using the commercial off-the-shelf simulation package (CSP) Simul8. This models the relationship in the health care supply chain between the NBS Processing, Testing and Is-suing (PTI) facility and its associated hospitals. However, as the number of hospitals increase simulation run time be-comes inconveniently large. Using distributed simulation to try to solve this problem, researchers have used techniques informed by SISO’s CSPI PDG to create a version of Simul8 compatible with the High Level Architecture (HLA). The NBS supply chain model was subsequently divided into several sub-models, each running in its own copy of Simul8. Experimentation shows that this distri-buted version performs better than its standalone, conven-tional counterpart as the number of hospitals increases
Purpose and benefits of hybrid simulation: contributing to the convergence of its definition
No full textThere is a growing trend in the number of M&S studies that report on the use of Hybrid Simulation. However, the meaning and the usage of the term varies considerably. Indeed, the hybrid simulation panel during last year's conference (WSC2016) laid bare the strong views, from the panelists and audience alike, as to what constitutes a hybrid model and what is new? The ensuing debate set the scene for this year's paper, in which we discuss the various perspectives on hybrid simulation by focusing on three aspects: its definition, its purpose and its benefits. We hope this paper will pave the way for further studies on this subject, with the objective of achieving a convergence of the definition of hybrid simulation.</p
Symbiotic simulation system: Hybrid systems model meets big data analytics
No full textSymbiotic simulation is one of Industry 4.0 technologies that enables interaction between a physical system and the simulation model that represents it as its digital twin. Symbiotic simulation is designed to support decision making at the operational levels by making use of real- or near real- time data that is generated by the physical system, which is used as an input to the simulation model. From the modeling perspective, a symbiotic simulation system comprises a hybrid systems model that combines simulation, optimization and machine learning models as well as a data acquisition module and an actuator. The actuator is needed when the symbiotic simulation system is designed to directly control the physical system without human intervention. This paper reviews the components of a symbiotic simulation system from the perspective of hybrid systems modeling and highlights research questions needed to advance symbiotic simulation study.</p
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