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Extensible Modeling and Simulation Framework
(XMSF)
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Name: Ekrem Serin
Service/Organization: TU
Navy
Rank/Title: Ltjg
Country: Turkey
Curriculum: Computer
Science
Purpose: Networking is a common problem for Networked Virtual Environments. In order to communicate with other entities a variety of communication protocols are used. Historically these communication protocols are hard coded into the software system and all nodes that participate into the environment should implement the protocols to interact with others. These communication protocols require authoring and compiling by a trained programmer. When we introduce compiling process to the networked virtual environment, we destroy the extensibility and dynamicism of the virtual environment. This work will present design and development of a Networked Virtual Environment model that uses extensible schema based networking protocol and it will show that , it is unnecessary to hard code and compile the protocols into the networked virtual environments. Protocols can be loaded and extended at runtime. Besides that, protocols can be created with different fidelity resolutions which can be swapped at runtime based on the network state.
Approach: We are using java networking, XML and XSD definition languages in order to solve the poblem. We think that XML is a good choice to address this problem. Because it is easy to present as a protocol. To create a protocol which uses a binary format would be more difficult to understand, and parsers would need to be built from the scratch and compiled into the Net-VE architecture each time whenever protocol changes. XML is also becoming a standard for many different industries for representing data, so mixing data with the protocol is as simple as merging two XML documents. There is a downside to using XML. XML is simply not a compact way to express data. Messages written in XML will be much larger than a binary equivalent. The technique that we use to address this problem is replacing tags with binary. Binary tags are created by parsing the XSD document. When both ends have the same XSD Document (it means the same protocol) they have the same corresponding binary tags. When we get the binary data we look up the binary tags from the table that we created and replace them with element or attribute names. The end of the process is building XML DOM Tree gradually. This DOM Tree represents the data that we are interested in. We can query the DOM and retrieve the information that we need.
Plan of Action:
Project Specific URLs:
Screen Shots:
Text Based XML Serialization Example XFSP as a Communication Protocol in Net-VE
Maintainer: Curt Blais (mailto:clblais@nps.navy.mil(Curt%20Blais)?subject=XMSF
query)
Uniform Resource Locator (URL) for this page is
http://www.MovesInstitute.org/xmsf/iitsec2002/demos/serin/description.html
(16 October 2002) (official disclaimer)