Current Applications of the OAIS Model David Giaretta.
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Current Applications of the OAIS Model
David Giaretta
OutlineConformance – what does it meanExamples
NSSDCCDPPLotar
Conformance – what does it mean?Section 1.4: A conforming OAIS archive implementation shall:
Support the model of information described in section 2.2• But OAIS RM does not define or require
any particular method of implementation
Fulfill the responsibilities listed in section 3.1• OAIS RM does not specify mechanisms
Roadmap identifies areas suitable for OAIS-related standards
Negotiates and accepts Information Packages from information producersObtains sufficient control to ensure long-term preservationDetermines which communities (designated) need to be able to understand the preserved informationEnsures the information to be preserved is independently understandable to the Designated CommunitiesFollows documented policies and procedures which ensure the information is preserved against all reasonable contingenciesMakes the preserved information available to the Designated Communities in forms understandable to those communities
OAIS Responsibilities
NSSDC - DIOnAS Data migration project DIOnASUsing OAIS conceptsProducing AIP’sTransforming existing data to Canonical format from VMS operating system specific format
Maintaining metadata to specify VMS-specific features
AIP
Based on ISO 12175 (SFDU packaging)ADID is an internationally object-type-unique identifier
Points to additional metadataThis metadata may initially be very simple BUT can be enhanced later
SFDU concept
NSSDC - IMAGE satellite dataNSSDC provided software to IMAGE project to convert their “Level-0.5” data products into AIPs
Original data is tar files containing “Universal Data Format (UDF) files.
Consumers will be provided with the UDF files plus software to read these
This may change as UDF falls out of use
IMAGE satellite data
Negotiates and accepts Information Packages from information producersObtains sufficient control to ensure long-term preservationDetermines which communities (designated) need to be able to understand the preserved informationEnsures the information to be preserved is independently understandable to the Designated CommunitiesFollows documented policies and procedures which ensure the information is preserved against all reasonable contingenciesMakes the preserved information available to the Designated Communities in forms understandable to those communities
OAIS Responsibilities
CDPP CDPP created in 1998
about 10 missions (WIND, ARCAD, …), 30 experiments, 100 data sets
OAIS typeInformation objects and type of objectsDomain dictionary (has already been run in on many missions)Modeling of delivered data
Standards and tools (examples)Data description in EAST is required from the producers
Tools are provided to create these
CDPP
Standards Tools
Basic standard for number coding
CCSDS EAST (syntactic description)
CCSDS DEDSL (semantic description)
OASIS (syntactic and semantic description)
PVL (delivery files) PVL parser and generator
CDPP data deliveryExample of data delivery model
RepresentationInformation
Data Objects
PDISourceContextReference
EASTStructuresheet
Catalogs
Data EntityDictionary
DED File
Descriptive docs
DIF
Data files
Mission, experiment descriptive files
MissionExperiments
Data set (main, auxiliary data, images)
EASTThe EAST language was designed to meet three objectives in order to enable :
a complete description of any given data format, without any 'ephemeral' references to any short-life file management systems, access to the values of the data by means of generic tools which do not require writing of even a single line of specific code for the data to be read, formatting the data on their storage or exchange medium while guaranteeing a structure that matches their description.
The EAST language is an international standard (CCSDS and ISO).Tools based on this standard have been developed. They can be used to help players throughout the "data life cycle".
EASTCNES point of view : EAST success will be achieved by using free tools. The user by using the OASIS tool doesn ’t have to learn a new language.
package logical_PRODUCT_X_SUN_FCSTC000 istype PRODUCT_X_NAME is (PRODUCT_X) ;for PRODUCT_X_NAME'size use 72 ;type AGENCY_ID is (CNES, NASA, USER_ESA, BNSC, CCSDS) ;for AGENCY_ID'size use 8 ;type NUMBER_TYPE is range 0 .. 9999 ;for NUMBER_TYPE'size use 32 ;type PRODUCT_ID_TYPE is record NAME : PRODUCT_X_NAME ; PRODUCER : AGENCY_ID ; NUMBER : NUMBER_TYPE ;end record ;for PRODUCT_ID_TYPE use record NAME at 0 * WORD_16_BITS range 0 .. 71 ; PRODUCER at 4 * WORD_16_BITS range 8 .. 15 ; NUMBER at 5 * WORD_16_BITS range 0 .. 31 ;end record ;for PRODUCT_ID_TYPE'size use 112 ;
Some lines of EAST
Snapshot d ’écran OASIS
Data Entity Dictionary Specification
Language Design Goals of DEDSL
Able to carry the definitions of data elements for various purposes
• Establish a discipline/domain dictionary independent of any particular data product usage
• Establish a product level dictionary that can be specialized from a domain level dictionary or created independently
Support registration of dictionaries as whole entitiesProvides standard attributes for use in the description of scientific data productsAttribute set easily extendable by any Data Entity Dictionary creatorSupport both human understanding and automated validation and processingHarmonized with ISO 11179-3 data element efforts
DEDSL ConceptsOne Abstract syntax with multiple concrete syntaxes defined for different languages and environmentsThe Abstract Syntax does not specify the schema or physical design of a Data Entity Dictionary implementationThe concrete syntax uses the constructs of the underlying language to implement the abstract modelEntities are described by the values of a set of standard Attribute values which may be extended by specifying user defined attributesAttributes are defined by a set of Descriptor values A Data Entity Dictionary consists of:
1 set of Dictionary Entity attribute definition0 or more User-defined attribute definitions1 or more Data Entity Definitions
A Data Entity Dictionary may be transferred using any agreed DEDSL concrete syntax specification.
Dictionary AttributesProvide information that applies to the entire Data Entity
Dictionary:IDENTIFYING
*Dictionary_name
RELATIONALExternal_dictionary_reference
DEFINITIONALDictionary_definition
REPRESENTATIONAL*Text_field_character_setCase_sensitivity default=not_case_sensitive
*Language
ADMINISTRATIVE*DEDSL_versionDictionary_versionDictionary_identifier
*= mandatory
HTML pages are inserted into MS WORD documents
Input Output of OASIS
EAST
DATA
Syntaxic Description
INTERPRETER :Library for readingand validating data
DATA GENERATOR :Library for writing data
(generation of data for simulation)
DEDPVL
SemanticDescription
DEDXML
XML translator
XSL ProcessorDEDDTD HTML
Users documentation
Data Description
Main CDPP difficulties
Non-availability of the Producer, or inadequate available resources
Diversity of experiments and data producedLate intervention of the Archive in the data production processAbsence of standard archiving structuring format (in Plasma Physics)No imposed schedule
Negotiates and accepts Information Packages from information producersObtains sufficient control to ensure long-term preservationDetermines which communities (designated) need to be able to understand the preserved informationEnsures the information to be preserved is independently understandable to the Designated CommunitiesFollows documented policies and procedures which ensure the information is preserved against all reasonable contingenciesMakes the preserved information available to the Designated Communities in forms understandable to those communities
OAIS Responsibilities
LOTAR
Long Term Archiving and Retrieval and Product Data within the Aerospace Industry
AIRBUSMTUEADSFairchild DornierPROSTEP AGProSTEP iViP Association
Requirements
Very large number of 3-D CAD modelsVarious formats – software dependent
• “quasi-safe for about 10 years”
Not safe enough for Legal and product liability
Legal:Ability to verify the conformity of a part with its documentationSystem has to enable the user to assure the provisions of a law regarding data security and protection of data privacy over the life cycle of the archivesPossibility to audit the process of archiving and retrieval
SecurityEnsure the information is understandable by the Designated Community without the assistance of the information producers……
Approach
Use vendor neutral ISO 10303 (STEP)Use OAIS RM
Document examines all the functional entities in great detailRecognises that Designated Community may be broadened
Negotiates and accepts Information Packages from information producersObtains sufficient control to ensure long-term preservationDetermines which communities (designated) need to be able to understand the preserved informationEnsures the information to be preserved is independently understandable to the Designated CommunitiesFollows documented policies and procedures which ensure the information is preserved against all reasonable contingenciesMakes the preserved information available to the Designated Communities in forms understandable to those communities
OAIS Responsibilities
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