Transitioning frameworks towards the Semantic Web

Digital Enterprise Research Institute www.deri.ie

Transitioning web application
frameworks towards the Semantic Web
(Master thesis progress report)

Benjamin Heitmann

Chapter 1
 Copyright 2007 Digital Enterprise Research Institute. All rights reserved. www.deri.org

Overview

Part 1: Introduction

About me


Example use case and Problem Statement

Methodology


Part 2: Contributions

Survey of 54 Semantic Web applications and papers

Analysis of requirements based on application types


In Progress: Evaluation of current framework approaches


Part 3: Outlook


2 of 42 Benjamin Heitmann


Introduction

Chapter 3

About me

Research topic: software engineering for the

Semantic Web
Helped with ActiveRDF

Wrote the SIOC explorer (based on ActiveRDF)

Started packaging components for reuse

Participation:

Paper about using ActiveRDF to support building a

complete Semantic Web application


Example use case: tracking a music community

?

Solution: Reusing Community Content

linked data:

web site
exporters

microformats (contact,
location, event)

after
aggregation:


Problem statement

How can we build such an application?

manual implementation is required


Problems:

– high learning curve
– no reuse of existing infrastructure and experience
Question: Why is there no framework for building a

complete Semantic Web application?
Answer: unknown requirements


What common application types?


What components do they share?



Methodology

Literature General idea: extract

review framework from real
prescriptive,
applications
analyse vision
and potential

Requirements
Evaluation
Application
Survey of current
types and
descriptive, approaches
components
based on
existing
implementations



Preliminary results of
Semantic Web Application Survey

Chapter 9

Working Definition:
Semantic Web Application

1. Every application
allows the user to perform a specific task


2. This leads to the requirements:
User: requires an interface


to perform: requires application logic


the task: is represented by data


3. To solve the task by utilising the Semantic Web
the support of Semantic Web standards is required


e.g. RDF, RDF Schema, SPARQL or OWL



The survey

NASA
Museum
Flink Dbin Semantic Annotea
Finland Organizer
Semantic
Foafing
Bibster MusiDB Swoogle Media
the music
Wiki

Paper RDF FOAF Fungal
Confoto
Puppy Homepage Map Web

Personal
CS Aktive
Publication Anno Terra Seco DOPE
Space
Reader

http://activerdf.org/survey/
54 applications, 34 properties


Sources of the survey

Semantic Web Challenge (at ISWC)

90 % of entries fit definition


41 entries in total

results from 2003 to 2006 available


Semantic Scripting Challenge (at ESWC)

all entries fit definition


13 entries without overlap from Sem. Web Challenge


results from 2005 to 2007 available


Both challenges required:

description of implementation and capabilities


published as paper



Excluded source

Sweet Tools List

contains 542 “tools”


privately maintained by Michael K. Bergman


Reasons for exclusion

time constraints


most entries have no academic publication


more then 50 % of them do not fit application definition


all of them are general purpose tools


majority can only be used to build parts of an application



Acquiring the data

source for data: papers, code mostly unavailable

 iterative process:
look at applications


create new properties


many projects did not specify implementation at all

 incomplete descriptions or properties from
literature review lead to “unspecified” properties
 Disclaimer:
Validation of data by authors of the papers in the future



Application Types

majority: semantic

portal
5
 only one third support
5
editing
5
31
6
semantic portal
7 semantic annotation
semantic repository
not an application
semantic authoring
semantic desktop application


Semantic Viewer/Browser

Example: FOAF Map

 Reads FOAF Files
 puts locations of People on Google Maps


Semantic Portal

Example:

Museum Finnland
 Integrates data
about artefacts
from multiple
museums
 allows faceted
browsing
 recommends
similar items


Semantic Annotation

Example:

Confoto
 Add meta
data about
people and
events to
photos


Semantic Repository

Example: NASA Semantic Organizer

 Add documents and binary files
 Annotate them with semantic metadata


Semantic Authoring

Example:

Semantic
MediaWiki
 Add semi-
structured
information
 Add schema
 View
information


Semantic Desktop Application

Example: DBin

 enables
sharing of
data about
specific topics
 provides tools
to build a
community
around the
topic


Semantic Web Standards and Schemas

RDF support: 80%

RDF 44
OWL support:
OWL 
24
50%
other query langs 8
SPARQL SPARQL support
7 
RDFS as high as
6
DAML previous query
3

languages
9 18 27 36 45
Many projects

use custom
others 34
schema
Dublin Core 4
RSS 1.0 7
Even Standard

FOAF 9
schemas used
unspecified 12
mostly once
private 14
(“others”)
9 18 27 36 45


Implementation

RDF Libraries
Scripting Languages
Languages

11
2
3 5
2
4
10 2
19
16
3 3 5

Sesame
RAP (PHP)
Ruby
Jena
Scripting Python
ActiveRDF (Ruby)
Java Perl
RDFLib (Python)
Prolog PHP
Redfoot
Redland
25% of all projects did not specify implementation



Architecture Types

majority: centralised

 second biggest:
6
decentralised and peer
3
to peer architecture
6

32
8
centralised server
decentralised server network
peer to peer
stand alone app
other


Application Domains

Knowledge Management 17

Infrastructure 9

Publishing 9

Research 7

Geospatial Information 7

Life Sciences 3

History 3

Social Network Analysis 2

Search 2

Collaboration 2

Arts 2

4 8 12 16 20


Degree of openness (1)

yes no unspecified offline
Alignment/
Integration
Editing majority: no

5
Can use External Data 15
9
majority: yes
12 13
Data Updates
majority: yes semi-automatic
manual
not needed
Schema Updates unspecified
majority: no automatic


Degree of openness (2)

yes no unspecified

Unstructured text supported
no real priority

Semi-structured data supported
equal distribution

inferencing of new knowledge
no real priority

data export / reuse of app as new data source
majority: yes, good for Linking Open Data


Unsupported at the moment

mash-ups / visualisation of data

multimedia content

collaboration

multilingual content

tracking authorship and provenance

trust

semantic transport layer


(unsupported by definitive majority)



Requirements

Chapter 29

Application types

Semantic Authoring
Semantic Repository
add binary and add semi-structured data
and schemas
structured data

Semantic
Semantic Annotation
Desktop
add only meta data
Application

Semantic Portal
Semantic Viewer
integrate and view
view one data source
multiple sources

an application can have multiple types at the same time



Semantic Viewer

Example: FOAF Map

 Capabilities:
Components:

very simple: just view and

navigate Data interface: to local

or remote store
one source with one

schema User Interface:

provides navigation
only read access, no

and visualisation
editing
Application logic:
Requirements: 

binds data to interface
RDF data support

Search

Navigation and

Visualisation of the data
domain


Semantic Portal

Example: Museum Finnland

 Capabilities: Components:

Uses multiple different data

Crawler: aggregate

sources data from different
Requirements: (remote) sources

Integration Service:

Integration of multiple data

integrate data and
sources
schema
Alignment of multiple

Persistence layer:

schemas
materialise the
Object Consolidation

integration results
support for Semantic Web

data and schema formats


Semantic Annotation

Example: Confoto

Components:
 Capabilities: 
annotate resources with meta Annotation Interface:
 
data but do not add new ones guides user in
resource annotation
Requirements:

Persistence layer:

Write support in User

storage for user
Interface
annotation
Write support in persistence



Semantic Repository

Example: NASA Semantic

Organizer Components:

 Capabilities: Repository Interface:

allows adding of
add new binary resources

resources
add new structured data

Content or document

annotate existing data

management service:
Requirements: provides versioning

and permissions
Integration of user provided

Binary repository:

data:
stores binary data
– binary data
– structured data


Semantic Authoring

Example: Semantic

Components:
MediaWiki 
Authoring interface:
 Capabilities: 
guides user in creating
add and edit semi-structured

semi-structured data
data
Semi-structured

add and edit schemas

persistence: no
Requirements:
 enforcing of schema,
runtime updates
supports semi-structured

possible
data
runtime evolution of data and

schema


Semantic Desktop Application

Example: DBin

Components:

 Capabilities:
Rich Interface: locally

Rich user interface

executed, low latency
Desktop Integration

Desktop Integration:

Requirements:

use and integrate local
supports Semantic Web data data and schema


local execution of application




In progress: evaluation

Chapter 37

First Evaluation

View
ActiveRDF

together with
Controller Ruby on Rails
ActiveRDF fits

transparently into the
Model
Ruby on Rails
Active Active architecture
Resource RDF

ActiveRDF bridges the gaps between data models

 Allows reusing the Rails eco-system:
 libraries and components

38 of 18 Benjamin Heitmann and Eyal Oren

Supported Application Types

Semantic Viewer:

low effort


Data Source: ActiveRDF provides remote or local RDF

source
Visualisation: Rails supports AJAX


Application logic: object oriented access to RDF triples


Semantic Portal:

medium effort


Crawler: manual implementation, reuse Ruby libraries


Integration Service: manual implementation


Persistence Layer: ActiveRDF supports read-write access



Unsupported Application Types

High effort for implementation:

all other application types


Semantic Annotation:

– Annotation Interface must be bound to RDF data
Semantic Repository:

– Management of documents and structured data has to be
integrated into semantic part of application
Semantic Authoring:

– semi-structured capabilities of user interface must be
implemented
– online updates of schema and data have to be visible in user
interface
Semantic Desktop Application:

– possible by using Joyent Slingshot: Rails Desktop Integration



Outlook

Chapter 41

ToDo for Master Thesis

Validate results of survey:

ask paper authors for corrections


Evaluate more approaches to support semantic web

application development
possible candidates: about 10


depends on availability of papers or source code


Writing:

Write down the results :)

maybe publish something


Should be finished at end of September



Summary

Question: How can we support the development of

Semantic Web applications?
 Answer:
look at existing Sem Web App publications which describe:

– capabilities
– implementation
derive requirements from those apps


Results:

6 types of semantic applications


Requirements and components for each type


Allows evaluation of current approaches


Recommendations for future Sem Web App frameworks



Transitioning frameworks towards the Semantic Web

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