Pythagoras Karampiperis, Demetrios Sampson e-mail:{pythk, sampson}@iti.gr
description
Transcript of Pythagoras Karampiperis, Demetrios Sampson e-mail:{pythk, sampson}@iti.gr
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20031
Enhancing Educational Metadata Enhancing Educational Metadata Management Systems to Management Systems to
support Interoperable Learning support Interoperable Learning Object RepositoriesObject Repositories
Pythagoras Karampiperis, Demetrios Sampsone-mail:{pythk, sampson}@iti.gr
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20032
What the problem is ?What the problem is ? A large number of digital learning resources exist, being
already described using different metadata models or even different application profiles of the same metadata model
“harmonising” this, by expecting that these resources will be eventually re-described in a standard and universally accepted model or profile might be too much to anticipate …
in order to avoid disregarding the possibility of searching and re-using LOs in these repositories, certain functional requirements should be considered when designing LRM Management Systems.
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20033
Design RequirementsDesign Requirements
Educational MetadataCreation / Modif ication
MappingEducational Metadata
Schemas
Support ofEducational Metadata
Standards
Structural & SemanticValidation
Educational MetadataManagement
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20034
Architecture of a LRM Management SystemArchitecture of a LRM Management System
Users
Editor / Wizard
Learning ResourceMetadata
XML SchemasXML Transformation
Maps
ManagementSystem
PublishingSystem
Map Generator
ValidationMapping
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20035
Architectural LayersArchitectural Layers
Interface Layer: A layer visible by the users of the LRMMS. It contains all the components of the user-interface. These are the XML editor/wizard, the management interface, the publishing interface and the map generator.
Non-visible Layer: contains all the repositories involved and the operations, which are performed. The repositories involved are the Learning Resource Metadata repository, the XML Schema repository and the XML Translation Maps repository and the operations are validation and mapping
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20036
Information StorageInformation Storage
XML Schemas Repository: contains the XML Schema files for the educational metadata models
Learning Resource Metadata Repository: stores the metadata description of the learning objects
XML Transformation Maps Repository: Transformation maps should be automatically generated by a corresponding mechanism, by associating a number of elements of one metadata schema to a number of elements of another schema
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20037
Editor / Wizard
XMLFiles XML Schemas
DOM
Learning ResourceMetadata
Validation Process
StructuralValidation
SemanticValidation
Fail
Fail
Pass
Pass
Validation Process Flow ChartValidation Process Flow Chart
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20038
XML Schemas
Learning ResourceMetadata
Map Generator
XMLFiles
Mapping
XML TransformationMaps
Mapping ProcessMapping Process
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 20039
Multi-tiered Database Model (1)Multi-tiered Database Model (1)
Ensures processing and storage effectiveness increased opportunity for security portability and extensibility
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200310
Multi-tiered Database Model (2)Multi-tiered Database Model (2)LRM Management system is partitioned into: Client application: provides a user interface on the
user's machine. Ideally, it knows nothing about how the data is stored or maintained.
Application server (middle tier): resides in a central networking location accessible to all clients and provides common data services. Coordinates and processes requests and updates from multiple clients and handles all the details of defining datasets and interacting with the database server.
Remote database server: provides the relational database management system (RDBMS).
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200311
Advantages (1)Advantages (1)
Encapsulation of business logic in a shared middle tier. Different client applications all access the same middle tier.
Thin client applications. Client applications can be written to make a small footprint by delegating more of the processing to middle tiers. Not only are client applications smaller, but they are easier to deploy. Thin client applications can be distributed over the Internet for additional flexibility.
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200312
Advantages (2)Advantages (2) Distributed data processing. Distributing the work of
an application over several machines can improve performance because of load balancing, and allow redundant systems to take over when a server goes down.
Increased opportunity for security. This model provides the capability of isolating sensitive functionality into tiers that have different access restrictions. This provides flexible and configurable levels of security. Middle tiers can limit the entry points to sensitive material, allowing controlling access more easily.
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200313
EMMA – A prototype implementation (1)EMMA – A prototype implementation (1)
The architectural design of the EMMA toolkit is based onmulti-tier database modeluse of Memory Based XML Native Repositories
conforming with the IMS Digital Repositories Interoperability – Core Functions Information Model specification
Use of the Simple Object Access Protocol (SOAP). The metadata produced by the EMMA are
conformed with the IEEE Learning Object Metadata 1484.12.1-2002 Standard.
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200314
EMMA – A prototype implementation (2)EMMA – A prototype implementation (2)
EMMA supports: authoring of educational metadata for the description of
educational resources and full management of the produced metadata descriptions
integration of different metadata specifications (Dublin Core, IMS Metadata) through the use of an advanced fully automatic mapping mechanism
metadata structural and semantic validation metadata publishing over the Internet through Web
Services and the use of SOAP protocol
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200315
EMMA – Authoring WizardEMMA – Authoring Wizard
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200316
EMMA – XML Viewer/EditorEMMA – XML Viewer/Editor
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200317
EMMA Mapping approach …EMMA Mapping approach … Data-Driven mapping mechanism, that is, it creates the
corresponding map between the attributes of various different schemas by examining the similarity of the data values that the attributes hold …
it does it in 3 nested parts by measuring the percentage of similarity between the data values of the attributes against some predefined similarity threshold value that “defines” the “minumum accepted similarity” between the data values of 2 attributes as a criterion to accept the mapping as valid
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200318
Test setting …Test setting … map different representations of the same real-
world entities using Dublin Core Ariadne Gem IEEE LOM
For the designing of the testing datasets, we used the ISO 639 and ISO3166-1 standards as the language
format scheme the ISO 8601 standard as the date format scheme
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200319
Classification of DatasetsClassification of Datasetsto examine the effect of data values heterogeneity, 3 different
datasets were identified with varying similarity, that is, low (less than 40%) Medium and high (more than 70%)
similarity
the similarity between the data values of the attributes is measured by the following formula:
DataSetinentitiesofnumberTotal
Similarity
SimilarityDataSetDataSettheofentity
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200320
Evaluation CriteriaEvaluation Criteria
Total evaluation criterion : the mean value of confidence, success and
mistakes
producedmappingsofnumberTotal
ContentofSimilarity
Confidencemapping
producedmappingsofnumberTotal
mappingscorrectofNumberSuccess
producedmappingsofnumberTotal
mappingswrongofNumberMistakes
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200321
Experiment 1: Experiment 1: Robustness Test Robustness Test
Mapping is assumed by the algorithm to be valid if the similarity between the entities is above a
specific thresholdEfficiency of the proposed mapping algorithm
depends on the selection of the similarity threshold parameter
Robustness test for three categories of the datasets according to
the similarity between entities
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200322
Robustness TestRobustness Test
0
20
40
60
80
100
Low 47.58 67.34 32.44 60.83
Medium 77.64 83.98 11.49 83.38
High 100.00 99.63 0.24 99.80
Confidence Success Mistakes Total
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200323
Experiment 2 : verification of effectivenessExperiment 2 : verification of effectiveness
to verify the effectiveness, we used a full datasets of IEEE LOM and Dublin Core metadata schemes representing the same learning objects (around 250 LOs)
to find that the result of the mapping algorithm were identical to the Annex B (Mapping to Unqualified Dublin Core) of IEEE 1484.12.1-2002 (Draft Standard for Learning Object Metadata) standard
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200324
IEEE LOM & DC Mapping (1)IEEE LOM & DC Mapping (1)Dublin Core IEEE LOM
Data Element Identifier Data Element
DC.Identifier 1.1.2 General.Identifier.Entry
DC.Title 1.2 General.Title
DC.Language 1.3 General.Language
DC.Description 1.4 General.Description
DC.Subject 1.5 General.Keyword
DC.Coverage 1.6 General.Coverage
DC.Type 5.2 Educational.LearningResourceType
DC.Date 2.3.3 LifeCycle.Contribute.Date
DC.Creator 2.3.2 LifeCycle.Contribute.Entity
DC.OtherContributor 2.3.2 LifeCycle.Contribute.Entity
DC.Publisher 2.3.2 LifeCycle.Contribute.Entity
DC.Format 4.1 Technical.Format
DC.Rights 6.3 Rights.Description
DC.Relation 7.2.2 Relation.Resource.Description
DC.Source 7.2 Relation.Resource
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200325
IEEE LOM & DC Mapping (2)IEEE LOM & DC Mapping (2)
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200326
IEEE LOM & DC Mapping (3)IEEE LOM & DC Mapping (3)
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200327
ConclusionsConclusions New functional & design considerations should be
satisfied to provide an effective LRM management system Integrating data from different data sources is
time-consuming and labor-intensive only few tools available to ease the task
The proposed architecture can be useful since it Supports the automatic data integration from different
metadata sources through the mapping mechanism Ensures the structural and semantic metadata validity
through the validation mechanismOpen Issues Real-time metadata integration over the Internet through
Web Services
University of PiraeusDepartment of Technology Education and Digital Systems
Centre for Research and Technology - Hellas(C.E.R.T.H.) Informatics and Telematics Institute (I.T.I.)
Pythagoras Karampiperis ICALT 200328
Contact DetailsContact Details
Pythagoras Karampiperis and Prof. Demetrios Sampsonpythk,[email protected]
Informatics and Telematics Institute, Centre for Research and Technology Hellas,42, Arkadias Street,Athens,GR-15234,GreeceandDepartment of Technology Education and Digital Systems,University of Piraeus150, Androutsou Street, Piraeus, GR-18534 Greece