AOP and HLA : A new aspect on distributed simulation development
- Authors: Pokorny, Timothy
- Date: 2009
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis develops a method for combining AOP and HLA, leveraging the separation-of-concerns approach used by AOP to allow the creation of core models, free from simulation distribution semantics. Through the use of automated tools, these models are then woven with a generic-HLA aspect, producing an HLA-enabled simulation component. Using AOP in this manner removes the need for model developers to have an in-depth understanding of the HLA, helping to remove the prime factor restricitng a broader uptake of distributed simulation technologies: development complexity.
- Description: Doctor of Philosophy
AOP and the HLA : Simplified federation development
- Authors: Pokorny, Timothy , Stratton, David , Smith, Philip
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at 2006 Fall Simulation Interoperability Workshop, Orlando, USA : 10th September, 2006 p. 1-11
- Full Text: false
- Reviewed:
- Description: Underpinning the development of distributed simulations in the defence community, the High Level Architecture (HLA) has gained acceptance due in part to its support for a broad level of interoperability. Encompassing a framework that loosely couples together simulation components developed and deployed on a diverse range of platforms, the HLA has the potential to enable increasing interoperation between otherwise disparate simulations. Long supported for the simulation efforts of the defence domain, use of the HLA within the wider business community has thus far been minimal. In domains where a wide variety of proprietary, customized simulation tools and generic desktop applications alike are used for simulation purposes, use of the HLA can help enable increased reuse and interoperability. Offering a common, standardised, low-level infrastructure, the HLA would allow simulation models otherwise isolated from one another to be used together. However, despite the potential benefits it could bring, the current development costs and complexities involved in the development of HLA-based distributed simulations have resulted in minimal uptake beyond the defence domain. To help facilitate the broader application of the HLA and the benefits it can provide, these complexities must be abstracted. Aspect-Oriented Programming (AOP) focuses on the separation of concerns. Through the definition of cross cutting functionality, platform or framework specific behaviour can be woven into existing works. Within the context of distributed simulation, such a facility could be leveraged in an attempt to apply HLA behaviour to pure objectoriented simulation models. Removing the tight coupling between model and distribution technology that currently exists in the HLA would allow for greater model reuse and return on investment in addition to dramatically simplifying the development process, thus reducing development costs. This paper provides a background motivating the use of HLA within the wider business community. Suggesting the AOP as a potential solution, it goes on to identify some of the problems that must be overcome.
- Description: E1
- Description: 2003002051
Fed WS: Web services access to active HLA simulations
- Authors: Pokorny, Timothy
- Date: 2004
- Type: Text , Conference paper
- Relation: Paper presented at SimTect 2004: the Ninth Simulation Technology & Training Conference, Canberra : 24th May, 2004
- Full Text: false
- Reviewed:
- Description: E1
- Description: 2003000927
Open source and the HLA : I swear it's here somewhere
- Authors: Pokorny, Timothy
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at the 2006 Fall SIW, Fall Simulation Interoperability Workshop, Orlando, USA : 10th September, 2006
- Full Text: false
- Reviewed:
- Description: The benefits of vibrant and active open source communities have been enjoyed in both commercial and non-commercial activities within many and varied domains. Previously the domain of altruists and enthusiasts, recent times have seen the uptake of free software grow at a significant pace. As commercial enterprises have come to accept open source software as potentially delivering numerous and substantial benefits to the products and services they provide, the number and momentum of open source efforts continues to build. While many commercial options fill the development, infrastructure and support needs that surround the HLA, the prevalence of open source software is minimal at best. Although commercial products can satisfy many needs, licensing costs remain prohibitive for small-to-medium enterprises and academic institutions. Of particular importance is the impact this can have on research activities within the domain. Where a vibrant open source community would provide a pool of resources on which research efforts could build, the current situation often requires significant effort be expended developing an environment in which the primary research can be conducted. This lack of such a resource has been conspicuous to many, and discussions surrounding community support for initiatives such as open source HLA Run-Time Infrastructures have been witnessed. Not totally devoid of any open source influence, those projects that do exist in the domain have as yet failed to reach the prevalence such endeavours often aspire to. This paper is a discussion of the current circumstances, the effect they can have and some of the efforts underway to begin addressing the problems, presented from the point of view of a research student within an academic institution.
- Description: E1
- Description: 2003002053
The model driven architecture : No easy answers
- Authors: Pokorny, Timothy
- Date: 2005
- Type: Text , Conference paper
- Relation: Paper presented at SimTect 2005: Simulation - fulfilling the promise, successes and visions for the road ahead, Sydney, Australia : 9th -12th May, 2005
- Full Text: false
- Reviewed:
- Description: The problems involved in the development of distributed simulation are varied and many. Solving these problems has been the topic of much research with one particular approach proving to be extremely popular: the Model Driven Architecture (MDA). Proposed by the Object Management Group (OMG), the MDA has been promoted as the cure to all the problems facing modern software development. Targeting the complexity of current software development techniques, the MDA is advertised as an evolutionary shift in the way software is created. Despite the bountiful and vivid claims made in the many corners of industry and academia, the MDA provides no easy answers. With a flavour distinctly reminiscent of the push towards CASE tools that occurred through the 1980s, to a large extent, the MDA presents to the world a pair of rose coloured glasses through which software development is reduced to an exercise in diagram drawing. While the advantages of such an approach are numerous, it also presents many disadvantages. Where a cure to development complexity is sought, a new form of complexity is introduced. The advantages of the MDA have been documented in numerous works, within both the modelling and simulation community and the wider software development population. This paper seeks to raise awareness of the often-ignored problems involved with the MDA by taking a critical look at the motivation, claims and processes involved.
- Description: E1
- Description: 2003001439
Web service performance analysis for the HLA
- Authors: Pokorny, Timothy , Cramp, Anthony
- Date: 2006
- Type: Text , Conference paper
- Relation: Paper presented at SimTect 2006 Conference Simulation: Challenges & Opportunities for a Complex and Networked World, Melbourne : 29th May, 2006
- Full Text: false
- Reviewed:
- Description: Recent developments have seen discussion on the use of web services within the modelling and simulation domains come to the fore. While web service uptake in the wider software development community has grown rapidly as the technologies involved mature, one persistent criticism has stood out among all others: performance. The use of an XML-based communications protocol was chosen primarily for the cross-platform benefits it provides, however, representation of messages in this format are of significantly larger size than previous, binary based approaches. Naturally, larger messages take longer to transport from one node to the next, thus raising questions around the level of performance reduction involved. While anecdotal evidence suggests that the performance penalties involved in the use of web service technologies is significant, there is a growing consensus within the mainstream software development community that this does not necessarily have to be so. This paper discusses the results of testing and experimentation targeted specifically at the High Level Architecture (HLA). Making use of an existing software tool that provides live HLA simulation information through a web service, the hypothesis of poor performance is put to the test.
- Description: E1
- Description: 2003001607