CS 566 Web Semantics

Professor

Antoniou Grigoris

Spring 2003

Antonis Misargopoulosmisarg@csd.uoc.gr

Athina Tziakitziaki@csd.uoc.gr

Introduction

Aidministrator, based in The Netherlands, is one of the leading companies in the process of creating the Semantic Web.

The Semantic Web will be more intelligent than the current web

Main activity aims at using the latest technology available to solve real life problems in customer projects

Aidministrator's software development is based on Advanced Java Software Engineering and Artificial Intelligence with university research and projects sponsored by the European Union

Products Overview (1/2)

Spectacle organizes and structures information and generates websites, intranets and extranets with the following goal in mind: present information in such a way that people find what they need.

Spectacle is used in knowledge management and e-commerce projects resulting in successful solutions.

Sesame, the storage and retrieval building block of the Semantic Web, is based on the new semantic web language RDF, or Resource Description Language. Sesame is distributed by Aidministrator as an Open Source product

Products Overview (2/2)

Product Description Customer

Sesame Semantic Web middleware. Stores and retrieves RDF (Resource Description Framework) and RDF-Schema annotated information. Developed as open source software.

Semantic Web developers

SpectacleE-commerce

Semantic navigation for web-based stores. Converts visitors into buyers through intuitive translation of customer wishes into product offers.

E-commerce companies

Spectacle Enterprise Thesaurus and taxonomy-based information disclosure. Discloses enterprise information resources based on understanding of the context of the user.

Companies with valuable information repositories

Spectacle Analysis Qualitative and quantitative graphical analysis of information. Helps information professionals understand their information collections.

Knowledge intensive companies, R&D departments

Spectacle Analysis

Spectacle Analysis is a development tool that enables applications for in-depth analysis of complex and/or large information repositories.

It visually shows the cohesion within large collections of information, typically collections of documents. It integrates structured and unstructured information from document repositories, Web sites, databases, and other applications.

One or more characteristics of the domain (classes or types) are defined. Then all documents are assigned to one or more of these types. The Cluster Map visualizes which documents belong to which types.

Figure.1 Animation.1

Spectacle Analysis

back Figure.1

Spectacle Analysis

back Animation.1

Spectacle e-Commerce

Spectacle e-Commerce is a development platform for the creation of website applications that shows the products of a virtual store in a new way

Spectacle makes it possible for visitors to explore a virtual store in order to learn what is there: they look around to learn what is there

The shop owner uses Spectacle as a sales instrument. Spectacle shows alternatives for products that are not

there

MyVacation demo

Spectacle Enterprise

Spectacle Enterprise is an instrument that organizations use to inform their employees and customers

The information and is organized in a comprehensive way. The user selects information in a small number of steps and uses a personal channel to find interesting information according to user’s characteristics

It is a unique tool that keeps track of the latest information by automatically classifying new information

Users: to easily explore or learn what is there. Employees: to find, share and add information.

Sesame (1/4)

RDF/RDFS storage and retrieval

Sesame is an architecture for persistent storage and querying of RDF and RDF Schema

It supports RQL and RDQL and can use main memory or PostgreSQL, MySQL and Oracle 9i databases for storage

It enables agents and applications to access information intelligently on behalf of the human user

It contains such high-level semantic information that it can be presented to human users in a convenient way only by a presentation environment as rich and powerful as Spectacle

Sesame is being developed as Open Source Software in corporation with NLNet as a research prototype and one of the first deliverables in On-To-Knowledge project

Sesame download

Sesame (2/4)

Architecture For persistent storage, Sesame needs a scalable repository DBMS To keep Sesame DBMS independent in which way of storing is best

fitted for which DBMS, all DBMS-specific code is concentrated in a single architectural layer of Sesame: Repository Abstration Layer

This RAL is an interface that offers RDF-specific methods to its clients and translates these methods to calls to its specific DBMS

Advantage: It makes it possible to implement Sesame on top of a wide variety of repositories without changing any of Sesame’s other components

Sesame (3/4)

Architecture Sesame’s functional modules are clients of the RAL:

RQL query module: evaluates RQL queries posed by user RDF administrator module: allows incremental uploading and deleting

RDF data and schema information RDF export module: allows the extraction of the complete schema and/or

data from a model in RDF format

Depending on the environment in which it is deployed, modules communicate with Sesame: Over HTTP, preferable in a Web context Using RMI or SOAP protocols

Sesame (4/4)

A generic architecture for RDF/S storage and querying, rather than just a particular implementation of such a system.

Architecture

Resource Description Framework - RDF RDF is a W3C recommendation that was originally designed to standardize

the definition and use of metadata-descriptions of Web-based resources. The basic building block in RDF is an object-attribute-value triple, commonly

written as A(O,V). RDF allows objects and values to be interchanged.

hasName ('http://www.csprofessors.org/antwniou/grhgorhs', "Grhgorhs Antwniou")

teaches ('http://www.csprofessors.org/antwniou/grhgorhs',‘http://www.courses.org/CS566')

title ('http://www.courses.org/CS566', "Semantic Web") It is possible to indicate that a given object is of a certain type

type ('http://www.courses.org/CS566',‘http://www.description.org/schema#Course') The RDF data model provides no mechanisms for declaring vocabulary that

is to be used

…/antwniou/grhgorhs …/CS566

Grhgorhs Antwniou

Semantic Web

hasName title

teaches

RDF Schema RDF Schema is a mechanism that lets developers define a particular vocabulary for

RDF data (such as teaches) and specify the kinds of objects to which these attributes can be applied (such as Professor). RDF Schema does this by pre-specifying some terminology, such as Class, subClassOf and Property, which can then be used in application-specific schemata.

The subClassOf property allows the developer to specify the hierarchical organization of classes. Objects can be declared to be instances of these classes using the type property. Constraints on the use of properties can be specified using domain and range constructs.

…/antwniou/grhgorhs

…/CS566

Professor Course

CSProfessor

teaches

Type

SubClassOf

domain range

Schema

teachesDataType

Resource Query Language - RQL

RQL is a query language for formulating queries on RDF Schema and Data. The output of RDF Schema queries is again legal RDF code, which allows

the output of queries to function as input for subsequent queries. The core queries are the basic building blocks of RQL, which give access to

the RDF Schema specific contents of an RDF triple store. The query Professor returns all instances of subclasses of Professor. We

can ask for all direct instances of Professor, ignoring all instances of subclasses, through the query ^Professor.

RQL, being based on OQL, also allows a select – from – where construct. For example, the query

select Yfrom CSProfessor{X}.teaches{Y}

returns all courses are being taught by CSProfessors. RQL relies on a formal graph model that enables the interpretation of

superimposed resource descriptions by representing properties as self-existent individuals and introducing a graph instantiation mechanism that permits multiply classification of resources.

RQL vs. Query Languages (1/2)

RQL vs. Query Languages (2/2)

Sesame vs. competitive Products

Portfolio

case Bouwradius case De Flint case MegaSportZone case OTK case VacanceSelect

Bouwradius (1/2)

Bouwradius Information Monitor  

Bouwradius is a knowledge centre in the Building and Construction sector in the Netherlands

Aidministrator has been asked to develop a knowledge infrastructure as part of the knowledge management strategy of Bouwradius

The goal is to distribute information in a convenient way Bouwradius wishes to distribute information to different

target groups like teachers, internal employees and coordinators hidden from others in- and outside the organization

Bouwradius (2/2)

Together with Bouwradius, Aidministrator created different contexts that suited the tasks of different target groups

The knowledge infrastructure has been developed with Spectacle, which supports Exploration Contexts based on meta-information. Each profile gets a different view on the information.

The benefits for Bouwradius are: user convenience: short time needed to find information,

excellent overview easy maintenance: Exploration Contexts can be adapted to

changing organization, automatic classification of new information

incremental development: fast delivery, controllable process.

De Flint

Website Theater de Flint  

The website of Theatre de Flint, in Amersfoort - the Netherlands, has been designed and realized by Aidministrator Nederland

The site is Spectacle-based and kept up-to-date by the Flint personnel themselves

MegaSportZone

Website MegaSportZone

The Intersport MegaStores, located in Alkmaar and Groningen, are among the largest dedicated sports and outdoor activities retail stores in Europe

Both stores specialize in providing expert assistance to the casual and professional sportsperson

Emphasize the fun in sports by organizing special sport-related events and activities at both locations.

Aidministrator designed, developed and hosts the MegaSportZone on the Spectacle platform, which results in an easy to maintain website, intended to draw the sport- and fun-loving public to one of the physical MegaStores

The site provides information on the enormous amount of sporting and outdoor clothing and equipment that is available at the stores, and informs the visitors about the special services offered and the special events that are organized

OTK

On-To-Knowledge  

On-To-Knowledge is a project in the Information Society Technologies (IST) Program for Research, Technology Development & Demonstration under the 5th Framework Program. The program runs from 1999 to 2002

The On-To-Knowledge project applies Ontologies to electronically available information to improve the quality of knowledge management in large and distributed organizations

One of the results of the project is the Ontology Inference Layer OIL. Ontologies provide a shared and common understanding of a domain that can be communicated across people and application systems

VacanceSelect

VacanceSelect implements Spectacle forits biggest affiliate, Ilse Media.

VacanceSelect, one of the most successful and fastest growing Dutch travel agencies on the Internet, has selected Spectacle to present its products to its customers.

The first step in this process is the implementation of the site of VacanceSelect's biggest affiliate, Ilse Media.

Using Spectacle's Interactive Product Selection, VacanceSelect will be able to improve on the conversion rate of their current system, i.e. the percentage of visitors that actually makes a purchase.

Another reason for selecting Spectacle is pure speed: production tests have shown that Spectacle is up to 50 times faster than competitor systems

References

Technical Reports & Papers [1]Aimilia Magkanaraki, Grigoris Karvounarakis, Ta Tuan Anh, Vassilis

Christophides, Dimitris Plexousakis, Ontology Storage and Querying, Technical Report 308, ICS-FORTH, Heraklion, Crete, Greece, April 2002

[2]Jeen Broekstra, Arjohn Kampman, A generic Architecture for Storing and Querying RDF and RDF schema, Copyright © 2001 Aidministrator Netherlands bv.

[3]Antoniou Grigoris, A Semantic Web Primer

URLs www.aidministrator.nl www.sesame.aidministrator.nl www.w3.org/RDF/