Standards

From EuroVR Knowledge Base

Technology Standards

This sections presents the relevant activities which can contribute towards establishing standards for developing distributed virtual environments in the future.

DIS

Distributed Interactive Simulation (DIS) and its predecessor SIMNET have set standards for distributed interactive simulations.

This work has progressed the development of the High Level Architecture for distributed simulations.

HLA

Distributed simulation is an application of distributed systems technology that enables simulators to be linked together over networks such as the Internet so that they work together (or interoperate) during a simulation run. The HLA (High Level Architecture) is a standard that defines the distributed system technology to make this interoperability possible. Rather than a networking protocol (wire standard) like DIS, HLA defines an architecture with a set of API (Application Programmer's Interface) Standards. Simulation applications (known as federates in HLA) communicate by making calls to the HLA APIs. A piece of software known as the RTI (Run-time Infrastructure) implements the HLA API, and is responsible for transporting data from one federate to another. Like DIS, the HLA Standards are owned by IEEE. There are three documents that comprise the HLA Standard, all available from IEEE (W Pedrycz 1998):

• IEEE 1516-2000 - IEEE Standard for Modeling and Simulation (M&S) High Level Architecture (HLA) - Framework and Rules: This provides the rules and definitions for implementing and using HLA (IEEE product code SH94882).
• IEEE 1516.1-2000 - IEEE Standard for Modeling and Simulation (M&S) High Level Architecture (HLA) - Federate Interface Specification: This defines the various services provided by an HLA RTI, and contains the APIs (IEEE product code SH94883).
• IEEE 1516.2-2000 - IEEE Standard for Modeling and Simulation (M&S) High Level Architecture (HLA) - Object Model Template (OMT) Specification: This defines the format used for describing object models in HLA. An object model dictates what kinds of data a particular set of HLA federates will be exchanging (IEEE product code SH94884).

There is a fourth document that is not technically part of the definition of HLA, but that defines some of the recommended practices for using HLA. It is called IEEE 1516.3-2003 - IEEE Recommended Practice for High Level Architecture (HLA) Federation Development and Execution Process (FEDEP) (IEEE product code SH95088).

While the IEEE 1516 series of standards represents the "current" version of HLA, many HLA simulations are still using an earlier version of HLA known as HLA 1.3. This version was maintained by DMSO and the U.S. Department of Defense prior to IEEE Standardization.

A Commercial-off-the-shelf (COTS) simulation package is a term used to refer to software used by many simulationists to build and experiment with models. There have been various attempts to support interoperability between COTS simulation packages. Currently these approaches are not compatible. In attempt to support interoperability and to unify research and development activities in this area the HLA – COTS Simulation Package Interoperability Forum (HLA-CSPIF) has been created (Schalkoff 1989).

W3C

The World Wide Web Consortium (W3C) develops interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential. W3C is a forum for information, commerce, communication, and collective understanding (D Scharstein 2002). In its document “Architecture of the World Wide Web”, they describe core design components, constraints and good practices to the principles and properties of the World Wide Web: relatively simple technologies with sufficient scalability, efficiency and utility. The core design components of the architecture are: identification of resources, representation of resource state, and the protocols that support the interaction between agents and resources in the information space.

IETF

The Internet Engineering Task Force (IETF) (M Sonka 1998) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is open to any interested individual. The actual technical work of the IETF is done in its working groups, which are organized by topic into several areas, such as routing, transport, security, etc. One of their main goals is to define standards for these areas facilitating the compatibility, the interoperability and the exchange of information. Many architectures are being defined by the groups, such as for IPv6 addressing, TRILL, IPFIX, network protection, Path Computation Element (PCE), RSerPool, Secure Mobile and XCON.

WSRF

Web services must often provide their users with the ability to access and manipulate state, i.e., data values that persist across, and evolve as a result of, Web service interactions. While Web services successfully implement applications that manage state today, we need to define conventions for managing state so that applications discover, inspect, and interact with stateful resources in standard and interoperable ways. The WS-Resource Framework (Sturman 1992) defines these conventions and does so within the context of established Web services standards.

Initial work on the WS-Resource Framework has been performed by the Globus Alliance and IBM, who released initial architecture and specification documents with co-authors from HP, SAP, Akamai, TIBCO and Sonic for public comment and review on January 20, 2004. These documents were submitted to the OASIS standards group in March 2004. The WSRF Technical Committee has been formed to work on WS-ResourceProperties, WS-ResourceLifetime, WS-ServiceGroup, and WS-BaseFaults specifications. The WSN Technical Committee has been formed to work on WS-BaseNotification, WS-Topics, and WS-BrokeredNotification specifications.

The WS-Resource Framework is inspired by the work of the Global Grid Forum's Open Grid Services Infrastructure (OGSI) Working Group. Indeed, it can be viewed as a straightforward refactoring of the concepts and interfaces developed in the OGSI V1.0 specification in a manner that exploits recent developments in Web services architecture (e.g., WS-Addressing).

Ergonomics Standards

For a review of standards which relate to human safety and productivity relevant to interactive systems such as VR, see Dul, J., De Vries, H., Verschoof, S., Eveleens, W., Feilzer, A. (2004) “Combining economic and social goals in the design of production systems by using ergonomics standards”, 2004, Erasmus Research Institute of Management, Report Series

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