Utente:Bedo2991/SandboxHLA

Una high-level architecture (HLA) è un'architettura general purpose per sistemi di simulazione computerizzata distribuita. Utilizzando HLA, le simulazioni computerizzate possono interagire (cioè scambiarsi dati e sincronizzare azioni) con altre simulazioni indipendentemente dalla piattaforma di calcolo. L'interazione tra le simulazioni è gestita da Run-Time Infrastructure (RTI). Oggi HLA è lo standard di interoperabilità più comune per le simulazioni distribuite ed è ampiamente utilizzato per supportare l'analisi, l'ingegnerizzazione e allenamento in un ampio numero di domini differenti come:

Difesa
Imprese Spaziali
Gestione del traffico aereo
Energia
Off-shore
Industria ferroviaria e automobilistica
Manifatturiero
Salute

Technical overview

Una high-level architecture consiste delle seguenti componenti:

Interface specification, che definisce come i simulatori che adottano HLA interagiscono con la Run-Time Infrastructure (RTI). La RTI fornisce una libreria e una API che rispondono alle specifiche dell'interfaccia.
Object model template (OMT), il quale specifica quali informazioni sono comunicate tra le simulazioni e come sono documentate.
Regole (Rules), alle quale le simulazioni devono sottostare per essere in linea con lo standard.

Termilogia HLA comune

Federato: una entità di simulazione che adotta HLA.
Federazione: entità di simulazione multiple connesse attraverso RTI utilizzando un OMT comune.
Oggetto: un insieme di dati correlati spedite tra simulazioni.
Attributo: Porzione di dato di un oggetto.
Interazione: evento inviato tra entità di simulazioni.
Parametro: Porzione di dati di un interazione.

Specifiche di interfaccia

Le specifiche di interfaccia sono object oriented, con specifiche sia per C++ che Java.

Le specifiche sono suddivise in gruppi di servizio:

gestione delle federazioni
gestione delle dichiarazioni
gestione degli oggetti
gestione della proprietà
gestione del tempo
gestione della distribuzione dei dati (Data Distribution Management, DDM)
servizi di supporto

Object model template

The object model template (OMT) provides a common framework for the communication between HLA simulations. OMT consists of the following documents:

Federation object model (FOM). The FOM describes the shared object, attributes and interactions for the whole federation.
Simulation object model (SOM). A SOM describes the shared object, attributes and interactions used for a single federate.

HLA rules

The HLA rules describe the responsibilities of federations and the federates that join.^[1]

Federations shall have an HLA federation object model (FOM), documented in accordance with the HLA object model template (OMT).
In a federation, all representation of objects in the FOM shall be in the federates, not in the run-time infrastructure (RTI).
During a federation execution, all exchange of FOM data among federates shall occur via the RTI.
During a federation execution, federates shall interact with the run-time infrastructure (RTI) in accordance with the HLA interface specification.
During a federation execution, an attribute of an instance of an object shall be owned by only one federate at any given time.
Federates shall have an HLA simulation object model (SOM), documented in accordance with the HLA object model template (OMT).
Federates shall be able to update and/or reflect any attributes of objects in their SOM and send and/or receive SOM object interactions externally, as specified in their SOM.
Federates shall be able to transfer and/or accept ownership of an attribute dynamically during a federation execution, as specified in their SOM.
Federates shall be able to vary the conditions under which they provide updates of attributes of objects, as specified in their SOM.
Federates shall be able to manage local time in a way that will allow them to coordinate data exchange with other members of a federation.

Base Object Model

The Base Object Model (BOM), SISO-STD-003-2006 is a related standard by SISO to provide better reuse and composability for HLA simulations, and is highly relevant for HLA developers. It provides a way to specify conceptual models and how to map them to an HLA FOM. More information can be found at Boms.info.

Federation development and execution process (FEDEP)

FEDEP, IEEE 1516.3-2003, is a standardized and recommended process for developing interoperable HLA based federations. FEDEP is an overall framework overlay that can be used together with many other, commonly used development methodologies.

Distributed Simulation Engineering and Execution Process (DSEEP)

In spring 2007 SISO started revising the FEDEP. It has been renamed to Distributed Simulation Engineering and Execution Process (DSEEP) and is now an active standard IEEE 1730–2010 (instead of IEEE 1516.3).

Standards

HLA è definito dallo standard IEEE 1516:

IEEE 1516–2010 – Standard for Modeling and Simulation High Level Architecture – Framework and Rules
IEEE 1516.1–2010 – Standard for Modeling and Simulation High Level Architecture – Federate Interface Specification
IEEE 1516.2-2010 – Standard for Modeling and Simulation High Level Architecture – Object Model Template (OMT) Specification
IEEE 1516.3-2003 – Recommended Practice for High Level Architecture Federation Development and Execution Process (FEDEP)
IEEE 1516.4-2007 – Recommended Practice for Verification, Validation, and Accreditation of a Federation an Overlay to the High Level Architecture Federation Development and Execution Process

Machine-readable parts of the standard, such as XML Schemas, C++, Java and WSDL APIs as well as FOM/SOM samples can be downloaded from the IEEE 1516 download area of the IEEE web site. The full standards texts are available at no extra cost to SISO members or can be purchased from the IEEE shop.

Previous version:

IEEE 1516–2000 – Standard for Modeling and Simulation High Level Architecture – Framework and Rules
IEEE 1516.1–2000 – Standard for Modeling and Simulation High Level Architecture – Federate Interface Specification
IEEE 1516.1–2000 Errata (2003-oct-16)
IEEE 1516.2-2000 – Standard for Modeling and Simulation High Level Architecture – Object Model Template (OMT) Specification

STANAG 4603

HLA (in both the current IEEE 1516 version and its ancestor "1.3" version) is the subject of the NATO standardization agreement (STANAG 4603) for modeling and simulation: Modeling And Simulation Architecture Standards For Technical Interoperability: High Level Architecture (HLA).

DLC API

SISO has developed a complementary HLA API specification known as the Dynamic Link Compatible (DLC) API for the IEEE 1516-2000 version of HLA. The DLC API addresses a limitation of the IEEE 1516 and 1.3 API specification, whereby federate recompilation was necessary for each different RTI implementation. Note that this API has since been superseeded by the HLA Evolved APIs, informally known as Evolved DLC APIs (EDLC).

HLA Evolved

The IEEE 1516 standard has been revised under the SISO HLA-Evolved Product Development Group and was approved 25-Mar-2010 by the IEEE Standards Activities Board. The revised IEEE 1516–2010 standard includes current DoD standard interpretations and the EDLC API, an extended version of the SISO DLC API. Other major improvements include:

Extended XML support for FOM/SOM, such as Schemas and extensibility
Fault tolerance support services
Web Services (WSDL) support/API
Modular FOMs
Update rate reduction
Encoding helpers
Extended support for additional transportation (such as QoS, IPv6,...)
Standardized time representations

Vedi anche

Note

^ U.S. Defense Modeling and Simulation Office, RTI 1.3-Next Generation Programmer's Guide Version 4, U.S. Department of Defense, 2001.

Collegamenti esterni

The HLA Tutorial: a free tutorial (PDF) published 2012.

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[rti-prog-guide-1] U.S. Defense Modeling and Simulation Office, RTI 1.3-Next Generation Programmer's Guide Version 4, U.S. Department of Defense, 2001.

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