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IMS Shareable State Persistence Best Practice and Implementation Guide Version 1.0 Final

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IMS Shareable State Persistence Best Practice and Implementation Guide

Version 1.0 Final Specification

Copyright © 2004 IMS Global Learning Consortium, Inc. All Rights Reserved.
The IMS Logo is a trademark of IMS Global Learning Consortium, Inc.
Document Name: IMS Shareable State Persistence Best Practice and Implementation Guide
Revision: 18 June 2004

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Copyright © 2004 IMS Global Learning Consortium. All Rights Reserved.

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Table of Contents


1. Introduction
     1.1 Nomenclature
     1.2 References

2. Examples
     2.1 Bucket Identifier Discovery
     2.2 Application Example: Assess, Then Review, Activity Sequence

3. Alternate and Appropriate Usage
     3.1 Scope of Learners and Content

4. Persistence
     4.1 Persistence Values

About This Document
     List of Contributors

Revision History

Index


1. Introduction

The IMS Shareable State Persistence (SSP) Best Practice and Implementation Guide includes (but is not limited to) identifying types of data that should not be persisted using this mechanism as there are other specifications that provide for interoperability and persistence of that data (e.g., QTI, Simple Sequencing, etc.).

This is a short best practice and implementation guide. For details on implementation, most of the data can be found in the Information Model, the XML Binding, and the SCORM Profile.

1.1 Nomenclature

 
ADL Advanced Distributed Learning
IEEE Institute of Electronic & Electrical Engineering
IETF Internet Engineering Task Force
ISO International Standards Organization
LOM Learning Object Metadata (usually used in "IEEE LOM")
LTSC Learning Technology Standards Committee
RFC Request for Comment (usually used in "IETF RFC xxxx")
SCORM Sharable Content Object Reference Model
SSP IMS Shareable State Persistence Specification
VDEX IMS Vocabulary Definition Exchange Specification
W3C World Wide Web Consortium
XML Extensible Mark-up Language

1.2 References

 
[SSP, 04a] IMS Shareable State Persistence Information Model v1.0, A.Jackl, A.Panar, B.Towle, IMS Global Learning Consortium, Inc., June 2004.
[SSP, 04b] IMS Shareable State Persistence XML Binding v1.0, A.Jackl, B.Towle, IMS Global Learning Consortium, Inc., June 2004.
[SSP, 04d] IMS Shareable State Persistence SCORM Application Profile v1.0, A.Jackl, A.Panar, B.Towle, IMS Global Learning Consortium, Inc., June 2004.
[IEEE LOM] IEEE 1484-12:2002, Standard for Learning Object Metadata, (http://ltsc.ieee.org)
[IMSBUND] Using IMS Content Packaging to Package Instances of LIP and Other IMS Specifications v1.0, B.Olivier, M.McKell, IMS Global Learning Consortium, Inc., August 2001.
[IMSPLID] IMS Persistent, Location-Independent, Resource Identifier Implementation Handbook v1.0, M.McKell, IMS Global Learning Consortium, Inc., April 2001.
[RFC 1766] Tags for the Identification of Languages, (http://www.ietf.org)
[URI] IETF RFC 2396:1998, Universal Resource Identifiers (URI): Generic Syntax (http://www.ietf.org)

2. Examples

2.1 Bucket Identifier Discovery

The Shareable State Persistence specification does not include a method to discover bucket identifiers or specific information about allocated buckets; however, content objects created by a vendor or community of practice can use a predefined identifier for a bucket that would contain information about other buckets. For example, the identifier:

   urn:communityName.org:bucketIDs/bucketDirectory

can be used to allocate or inspect a bucket that contains directory information for other buckets used by the objects of the community of practice called "communityName". This directory information may vary between communities of practice, but it could, for instance, include a list of bucket identifiers with, for each bucket, the size, the GUID of the object that created it, and the intended purpose. Another vendor or community of practice might store other data for each bucket it creates inside such a directory bucket. Of course, it is important to choose as an identifier a value that is not likely to be used by anyone else. In the example above, a URN was used as identifier to avoid accidental name collisions.

2.2 Application Example: Assess, Then Review, Activity Sequence

It is common in learning applications to administer an assessment, evaluate the responses, and then review the assessment with the learner. The assessment itself is one activity. The review is another activity. By storing the learner-specific assessment details in a bucket, the assessment may enable such a review. The sequence would be as follows:

When launched, the assessment attempts to read the assessment results bucket. If such a bucket exists, the assessment clears the content. The assessment updates the content of the bucket with data about which items the user responded to, what the responses were, and so on. How to do this is not defined by the Shareable State Persistence specification, because it will depend on what the creator of the object needs in order to enable the review activity.

Depending on the implementation, the object for the review activity can be the same assessment object, or it could be a separate object that knows about the assessment, but only performs the review task. When the object for the review activity is launched some time after the assessment activity was completed, it attempts to read the bucket with the data stored during the assessment activity. If it finds the data, it then proceeds with the review. If it does not, it suggests a course of action to the user, e.g., do the assessment before attempting the review. Obviously, both the assessment content object and the review content object, if they are different, must agree on the same identifier or collection of identifiers for the review data. It is important to choose identifier values that are not likely to be used by any other objects. Since the identifier will not be read by human beings, but only by content objects, the identifiers can be long and complex.

3. Alternate and Appropriate Usage

There are types of data that should not be persisted using this mechanism as there are other specifications that provide for interoperability and persistence of that data. For example QTI and SS.

Where there exists a specification to handle storage of a specific data type , that data should not be stored in SSP Buckets. While one might store assessment data in these buckets, greater interoperability will be achieved if assessment data is stored as structured QTI data. This specification does not replace any other specification. The purpose of this specification is the runtime storage of data, not data for reporting or long-term storage.

3.1 Scope of Learners and Content

The scope of which learners or group of learners can use the bucket and the content objects which can see the bucket can be managed at the application profile level by utilizing the learnerScope and contentScope attributes in the Bucket class. The application profile determines how to use them and its impact on the runtime system.

4. Persistence

4.1 Persistence Values

There can be an "institutional" time limit. This is apart from either a time limit based on a "course" or a "learner". Maximum and minimum periods of persistence are set at the system level and are not in the scope of this specification.

About This Document

 
Title IMS Shareable State Persistence Best Practice and Implementation Guide
Editor Alex Jackl (IMS)
Team Co-Lead Robert Todd (DigitalThink)
Version 1.0
Version Date 18 June 2004
Status Final Specification
Summary This document describes the Shareable State Persistence Best Practice and Implementation Guide.
Revision Information June 2004
Purpose This document has been approved by the IMS Technical Board and is made available for adoption.
Document Location http://www.imsglobal.org/ssp/sspv1p0/imsssp_bestv1p0.html

 
To register any comments or questions about this specification please visit: http://www.imsglobal.org/developers/ims/imsforum/categories.cfm?catid=21

List of Contributors

The following individuals contributed to the development of this document:

 
Name Organization Name Organization
Brandt Dargue Boeing Angelo Panar ADL
Jeff Falls ADL James Simon Sun Microsystem
Fabrizio Giorgini GIUNTI Martin Spence Act E-Learning
Alex Jackl IMS Global Learning Consortium Robert Todd DigitalThink
Steve Jeyes CETIS Brendon Towle Thomson NETg
Owen McGrath UC Berkeley Edith Wells Boeing
Claude Ostyn Click2learn
 

 

Revision History

 
Version No. Release Date Comments
Base Document 1.0 16 November 2003 Initial version of the SSP specification.
Public Draft 1.0 23 February 2004 First public version of the specification.
Final Specification 1.0 18 June 2004 Formal Final Release of the specification.

Index

A
Assessment 1

I
IEEE 1
IMS Specifications
     Content Packaging 1
     Learner Information Package 1
     Question and Test Interoperability 1, 2
 

L
LOM 1
LTSC 1

P
Profile 1

R
RFC 1
Runtime 1

S
SCORM 1

V
Vocabulary 1

W
W3C 1

X
XML 1

 

 

 

IMS Global Learning Consortium, Inc. ("IMS") is publishing the information contained in this IMS Shareable State Persistence Best Practice and Implementation Guide ("Specification") for purposes of scientific, experimental, and scholarly collaboration only.

IMS makes no warranty or representation regarding the accuracy or completeness of the Specification.
This material is provided on an "As Is" and "As Available" basis.

The Specification is at all times subject to change and revision without notice.

It is your sole responsibility to evaluate the usefulness, accuracy, and completeness of the Specification as it relates to you.

IMS would appreciate receiving your comments and suggestions.

Please contact IMS through our website at http://www.imsglobal.org

Please refer to Document Name:
IMS Shareable State Persistence Best Practice and Implementation Guide Revision: 18 June 2004