Digital Object Architecture - Object Management Group · 2013-01-30 · Corporation for National Research Initiatives • Exists within the Digital Object Architecture with the goal

Corporation for National Research Initiatives

Digital Object Architecture

Christophe [email protected]

Jason [email protected]

Corporation for National Research Initiativehttp://www.cnri.reston.va.us


Presentation Overview

•Introduction

•Digital Information Object

•Notions of Digital Object

•Digital Object Architecture

•Digital Object Chaining


Introduction

Primordial Internet•TCP/IP was created to allow transmission of packets of data between disparate systems on ARPANET.

• Addresses are location dependent.

• Deals with where data goes, but not what it is, or who it is sent to.


Introduction

Contemporary Internet• DNS specifies who is where, as long as who does not move often.

• Addresses such as email and URLs are still location dependent.

• Application layer protocols such as HTTP use MIME typing to define what data is, but only address one-way communication.



•Introduction






• Exists within the Digital Object Architecture with the goal of making information a first class citizen on the Internet.

• Allows high level information to be moved around on the Internet much as packets of data are today.

•Aggregates relevant heterogeneous data and metadata.

• Solves the who is where problem of network addressing by using the CNRI Handle System®, a location independent global naming service.

• Describes the what of information in an concise and extensible manner.

Digital Information Object


Digital Information Object Intents of Use

• The Intents of use extensible typing mechanism specifies what a Digital Information Object contains.

• A specific Digital Information Object’s intent of use is described as a content type.

• Content types are registered and uniquely identifiable.

• A content type defines a unique set of operations that can be performed on specific information type.

• The set of operations is known as a content type signature.

• A content type signature can be implemented in different ways in the form of mobile code called servlets.



•Introduction






Digital ObjectContent Type(s) Requests

Information

Digital Object Overview

Disseminations

Unique Identifier


Hamlet

It’s a Book Get Page(2)


Hamlet


Hamlet

•Digital objects are uniquely identified in a given name space.

•Data elements reference sequences of typed bytes.

•A Digital Object can have zero of more Content Types to reflect the intents of use of its creator.

DataElement

DataElement

HamletContent Type

Operations

Content TypeOperations




•Introduction






Repository

Digital Object Repository

RA

P

Client

•Provides distributed Digital Object storage.

•Behaves as a Digital Object.

•Provides a dynamic acquisition and execution mechanism for the mobile code that implements the content type operations.

•Exclusively accessed using the Repository Access Protocol (RAP).

DisseminateDeposit


1 to many

Type Signature

Servlet

TypeSignature

Implementation

Type Signature API

ServletImplementation

Servlet API

Serv

ices

API

Ref

eren

ces

Content TypeOperations

Content Type Extensibility


hdl:type/repository

hdl: type/repositoryhdl: type/typedef URN

Handle Service

hdl:type/repository IOR:DLShttp://www.type.orgURL

hdl: type/book hdl: type/typedefURN

hdl: type/book1 hdl: type/typeimplURNhdl:type/typeimpl hdl:type/repositoryURN

Registerhdl:type/typedef

hdl:type/book

Type Signature

hdl:type/typeimpl

hdl:type/book1

Servlet

Content Type Registration


Identifier

Identifier

Type Signature

Servlet Attachments

Disseminator

hdl:type/repository

Digital Object Structures

DisseminatorIdentifier

Type Signature

Servlet Attachments

Identifier

DataElement

DataElement

Type Registry

Handle Service


Repository

Deposit

IdentifierClient C

Disseminator

Servlet

XYZ-1

Content Type Extensibility Mechanism

Disseminate

Identifier

Type Signature XYZ

Attachment

Repository 2

Deposit

DepositData

ElementData

Element

Client A

XYZ

Client B

XYZ-1

Dynamic Acquisition of Mobile code


Secure Digital Object EnvironmentExtensible Services

Extensible Dissemination Mechanism

Identifier

DisseminatorIdentifier

Type Signature

TypeSignature

Signature API Servlet API

Serv

ices

API

Servlet

Attachments

Disseminations

Req

uest

s Results

RepositoryServices

Servlet Attachments

DataElement

Disseminations

Req

uest

s Results



•Introduction






Digital Object Chaining

• Provides a building block approach to information management.

•Enables the creation of information and operation links.

•Content Chaining: a digital object’s data element can reference its respective content.

•Operations Chaining: servlets can dynamically establish links to external resources or digital object when executed.

•Content Type Chaining: chaining servlets can be designed to dynamically build digital object chains from input parameters.


Content Chaining Mechanism

StaticServiceRequest

Digital Object

•Digital Object ID•Disseminator ID

•Method Request•Parameters

orData Element

Typed Bytes

Type Signature Servlet

Extensible Services

•Type Signature ID•Servlet ID



Operation Chaining Mechanism

or•Digital Object ID

•Disseminator ID•Method Request

•Parameters Digital Object

DynamicServiceRequest

Method RequestSe

rvic

es A

PI

Servlet API

Servlet

•Type Signature ID•Servlet ID


Type Signature Servlet

Extensible Services

Digital Object

self


Digital Object Chaining Example

Example: ask the Babel Fish Object: generate an audio version of a French translation of Shakespeare's Hamlet.

Babel Fish

Babel FishType

4 5

Babel Translator

6

1

Shakespeare

3

8

Audio Tools

7

2

Hamlet


Data Exchange By Chaining

Query System

•Digital Object chaining allows for homogeneous data exchanges in a heterogeneous data environment.

•Digital Object Chaining provide a layer of abstraction over data formats, encoding and transport protocols.

Type A

Type B

Services

Type A

Type A

Type A

Documents

Digital Object Architecture - Object Management Group · 2013-01-30 · Corporation for National Research Initiatives • Exists within the Digital Object Architecture with the goal