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:
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.