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S E R I E S

SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES

FOR EUROPEAN SYNERGIES

COMMISSION OF THE EUROPEAN COMMUNITIES

FP7- INFRASTRUCTURES-2008-1

SP4-Capacities

SERIES Concluding workshop, Ispra, 28-30 May 2013

SERIES Concluding workshop, Ispra, 28-30 May 2013

Ignacio Lamata Martinez

University of Oxford

Ferran Obon Santacana, Martin Williams, Anthony Blakeborough, Uwe Dorka

WP2/NA1.3

A support platform for

distributed hybrid testing

SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES

2 SERIES Concluding workshop, Ispra, 28-30 May 2013

Contents

Introduction

What is Celestina?

Celestina Overview

Implementation

Validation Next steps



Introduction



Introduction

Distributed testing enables the use of resources at different locations to achieve a more representative simulation

Requires both engineering and computing science

Many efforts done for earthquake engineering distributed testing Ex. UK-NEES DHT, OpenFresco, NCREE, UI-Simcor, P2P

Internet Online Hybrid Test System...



Introduction

Main issues:

Limited support to plan and organize simulations

Null integration between different software

Earthquake engineering distributed testing can benefit from a tool that:

Helps researchers with organization and planning of simulations

Enables simulations to use heterogeneous software at each end



What is Celestina?



What is Celestina?

Celestina is a specification that provides an understanding framework to conduct the experiment workflow

WHAT has to be done, not HOW it should be done

Divides experimental activities into high-level (organization and planning) and low-level (actual data exchange)



What is Celestina?

Service integration by adding a layer to manage experimental testing

Two types of nodes in the Celestina network: Sky nodes Managers

Ground nodes Laboratory facilities



Celestina Overview



Celestina Overview

A Celestina node should provide three groups of services



Celestina Overview

Networking services Discovery of other Celestina nodes

“Friendbook” with known nodes in the network

Hybrid peer to peer network (P2P)



Celestina Overview

Definition services Verify feasibility of a simulation

Definition of a simulation plan

Agreement between participants on the terms the simulation takes place

Examples:

Link verification (low level network connection – illustrative)

Data compatibility (understanding of exchanged data types, endianness)

Simulation plan revision (dates, multi-site, etc)



Celestina Overview

Testing services Conduction of the simulation according to the simulation plan

Simulation workflow Locking a node for testing

Establishment of communication (definition of clients – servers channels)

Preparatory phase

Execution of the experiment

Result collection

Unlocking a node for testing and resource liberation

In case of error Abort and restart



Celestina Overview

Celestina general workflow



Celestina Overview

Semantics in Celestina

Data types (different ways to interpret a 4-byte number: integer, float, signed, unsigned...)

Data compatibility operation (addition, multiplication...)

Type of simulations (hybrid, multi-site, two-sites...)

Endianness

OWL language

W3C recommendation

Specifies ontologies = formal, explicit specifications of a shared conceptualization

Definition of a vocabulary to avoid misunderstanding



Implementation



Implementation

Celestina defines WHAT, not HOW

One possible implementation of the Celestina specification has been developed

Very flexible

Software generalization prioritised over speed – but code to improve performance has been developed

Implementations for both Sky and Ground nodes

The Ground node implementation includes high and low level activities

Java + MySQL



Implementation

Hardware abstraction of low-level activities High-level code delegates the actual implementation of

experimental device access to low-level code

High-level code calls abstract methods and the low-level code, which knows how to access the hardware, does the work

Examples File Connector

Network TCP Connector

FastJava Connector

External Command Connector



Validation



Validation

Celestina was developed and implemented at the University of Oxford (UOXF) and tested in partnership with the University of Kassel (UNIKA)



Validation

Specific tests conducted to test: Usual operation (File Connector)

Numerical testing (Network TCP Connector)

Collection of results

End of a test

Endianness

Speed (FastJava Connector)

Integration with external software (External Command Connector)

Numerical tests were supported by the programs developed by Ferran Obon at the University of Kassel, using Dorka's substructure algorithm



Validation

Some results:

Networking services exchanged networking information successfully

Definition Services tested link and data compatibility successfully, as ordered by the Sky node

Stable tests were conducted by using different hardware connectors

Very small overhead – almost as conducting the experiment without Celestina. Similar results as the ones obtained between UNIKA and UOXF using other software

* Test conducted with Univ. Kassel under similar circumstances

* *

Average time required

per test step (latency

not guaranteed)



Next Steps



Next Steps

Use Celestina in real distributed tests

Create user-friendly Celestina implementations

Use of Celestina in real-time distributed testing

Promote Celestina to be integrated with existing software

Support of experimental resources booking

Result collection in a integrated EE data format



Next Steps

How to use Celestina?

Use the existing Celestina implementation used for the validation.

Develop a new Celestina implementation.

Adapt existing software to be used under Celestina (note that one of the HardwareConnectors in the validation, enables use of non-Celestina external software).

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