XML Content Management and Security

Semantic Web:

―The Semantic Web is a major research initiative of the World Wide Web Consortium

(W3C) to create a metadata-rich Web of resources that can describe themselves not only by how they should be displayed (HTML) or syntactically (XML), but also by the meaning of the metadata.‖ – From W3C Semantic Web Activity Page

―The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.‖ –Tim Berners-Lee, James Hendler, Ora Lassila,The Semantic Web, Scientific American, May 2001

Motivations:

Difficulties to find, present, access, or maintain available electronic information on the

web.

Need for a data representation to enable software products (agents) to provide intelligent access to heterogeneous and distributed information.

The Semantic Stack and Ontology Languages:

RDF [ Resource Description Framework ]:

Express meaning on the web that machines can understand.

W3 Specification for Xml code:

<person name=―Jane‖>

<sells product=―books‖/>

</person> Rdf code

<rdf:Description about=―[Jane]‖ xmlns:my=―[my]‖>

<my:sells

rdf:resource=―[books]‖

/>

RDF consists of two parts

– RDF Model (a set of triples)

– RDF Syntax (different XML serialization syntaxes)

RDF Schema for definition of Vocabularies (simple Ontologies) for RDF (and in RDF)

RDF  Data  Model:

Resources:

– A resource is a thing you talk about (can reference)

– Resources have URI‘s

– RDF definitions are itself Resources (linkage)

Properties:

-                                             slots, defines relationship to other resources or atomic values

Statements:

– ―Resource has Property with Value‖

– (Values can be resources or atomic XML data)

-                                             Similar to Frame Systems

A simple Example:

Statement:

– ―Ora Lassila is the creator of the resource  http://www.w3.org/Home/Lassila‖

Structure:

–       Resource     (subject)      http://www.w3.org/Home/Lassila

–Property (predicate)  http://www.schema.org/ - Creator://www.schema.org/#Creator

–           Value       (object)       ―Ora Lassila‖

Directed graph:

Collection Containers:

Multiple occurrences of the same Property Type doesn‘t establish a relation between the values

– The Millers own a boat, a bike, and a TV set

– The Millers need (a car or a truck)

– (Sarah and Bob) bought a new car

RDF defines three special Resources:

– Bag  unordered values          rdf:Bag

– Sequence  ordered values rdf:Seq

– Alternative        single value rdf:Alt

• Core RDF does not enforce ‗set‘ semantics amongst values

A Formal Model of RDF:

RDF itself is mathematically straightforward:

– Basic Definitions

•                           Resources.

•                           Properties ÌResources    called

•                           Literals

• Statements = Resources        ´ Properties

X{Resources Èliterals}

– Typing

•                           rdf:type Î Properties

•                           {RDF:type, sub, obj} Î Statements Þ obj

Î Resources

Formal Model of RDF II:

Reification

•                     rdf:StatementResource-Properties

•                      rdf:predicate, rdf:subject, rdf:objectProperties

•                     Reification of a triplepred, sub, objof Statements

is an element r of Resources representing the reified triple and the elements s1, s2, s3, and s4 of Statements such that

– s1: {RDF:predicate, r, pred}

– s2: {RDF:subject, r, subj}

– s3: {RDF:object, r, obj}

– s4: {RDF:type, r, [RDF:Statement]}

– Collections

RDF:Seq, RDF:Bag, and RDF:Alt Resources-Properties

•                     There is a subset of Properties corresponding to the ordinals (1, 2, 3, …) called Ord. We

refer to

•                     elements of Ord as RDF:_1, RDF:_2, RDF:_3, …

RDF  Syntax I:

Data model does not enforce particular syntax

•        Specification suggests many different syntaxes based on XML

General form:

Resulting Graph:

<rdf:RDF>

<rdf:Description about=‖http://www.w3.org/Home/Lassila‖>

<s:Creator>Ora Lassila</s:Creator>

<s:createdWith rdf:resource=―http://www.w3c.org/amaya‖/>

</rdf:Description>

</rdf:RDF>

RDF Schema (RDFS):

RDF just defines the data model

•                     Need for definition of vocabularies for the data model – an Ontology Language!

•                     RDF schemas are Web resources (and have URIs) and can be described using RDF RDF-Schema: Example:

Rdfs: subclass Of:

<rdfs:description about=„Xyz:Minivan―>

<rdfs:subclassOf about=„xyz:Van―/>

</rdfs:description>

<rdfs:description about=„myvan―>

<rdf:type about=„xyz:MiniVan―/>

</rdfs:description>

Predicate Logic Consequences:

Forall X: type(X,MiniVan) -> type(X,Van).

Forall X: subclassOf(X,MiniVan) -> subclassOf(X,Van).

Rdf:property:

<rdf:description about=„possesses―> <rdf:type about=„….property―/> <rdfs:domain about=„person―/> <rdfs:range about=„vehicle―/>

</rdf:description>

<rdf:description about=„peter―>

<possesses>petersminivan</possesses>

</rdf:description>

Predicate Logic Consequences:

Forall X,Y: possesses (X,Y) -> (type(X,person) &

type(Y,vehicle)).

Simplification      rules:

•                     People specifying text for arbitrary RDF processors can use any simplification

•                     Processors of arbitrary RDF therefore must accept all simplifications

•                     Special-purpose XML formats can be RDF- compliant while disallowing simplifications, requiring them, or exploiting them in specific ways

Containers vs. Multiple values:

•                     A property can appear more than once with different values

•                     What is true of a container isn‘t necessarily true of its contents and vice versa

•                     ―aboutEach‖ lets us get to the contents when we already have a container

•                     ―aboutEachPrefix‖ in effect manufactures a container based on URLs

Reified       statements:

•                     We reify statements so that we can talk about them rather than asserting them

•                     ―Charles Dickens is the author of Bleak House‖ asserts a property of Charles Dickens

•                     ―Jack believes that Charles Dickens is the author of War and Peace‖ asserts a property of

Jack, not Charles Dickens

RDF  Classes:

Are groups of Web resources

•                     Have URLs to identify them

•                     The special class ―rdfs:Literal‖ consists of all possible RDF string values

XLANG:

It is aExchange Language – Web Service for Business Process Design. Microsoft – runnable on all platforms. It Written format is XML. It is a Biz Talk Application Designer.

Motivation:

It Enabling technology for new standards and descriptions around existing technologies => develope language which is able to handle.

It is a Business imperative to ease the automation of business processes& to describe a standard for reuse by other tools.

Relationship with WSDL:

ⁿ        Grounding of a XLANG service description is defined by using WSDL

ⁿ        XLANG describes the behavior as part of a business process

ⁿ        Actions in XLANG = operations of WSDL

Business Process (I):

ⁿ        Contract between two ore more parties

ⁿ        XLANG service description describes the behavior

ⁿ        It is used a map – describes the connections between the ports

ⁿ        Each port is added to the map

Correlation:

ⁿ        Correlation tokens

ⁿ        For automated instance routing

ⁿ        Messages to the correct port and instance

^¨                  Instance: interaction with which the behavior of the service is represented

ⁿ        Calculated lifetime

ⁿ        Correlation set

ⁿ        Correlation group

WSFL:

WSFL describes Web Service compositions. It is a Usage patterns of Web Services: describes workflow or business processes. It is a Interaction patterns: describes overall partner interactions.

Using Flow Models:

•                     ―Public flows‖ provide a representation of the service behavior as required by its users.

–   Typically, an abstraction of the actual flow begin executed

–   Defines a ―behavioral contract‖ for the service.

–   Internal implementation need not be flow-based.

– Flows are reusable: specify components types, but not what specific services should be used!

–   ―Private flows‖ are the flows executed in practice.

–   WSFL serves as a ―portable flow implementation language‖

•                     Same language is used in WSFL to represent both types of processes.

Global Models:

ⁿ        Global models describe how the composed Web Services interact.

ⁿ                  RosettaNet automated.

ⁿ                  Like an ADL.

ⁿ        Interactions are modeled as links between endpoints of two service interfaces (WSDL operations).

ⁿ        An essentially distributed description of the interaction.

Discovery: Finding Meta-data:

•                     Static binding requires service ―libraries‖.

•                     Dynamic binding requires runtime discovery of meta-data

Web Content Management:

•                     Every thing from price list to contact list, home page ,personal info are becoming a internet content

•                     Volume of content on the internet continuous to grow in size & types of content.

•                     Requirements for Solid web content management solution & dynamic content distribution

Definition:

•                     Web Content Management is generally defined as a combination of clearly defines roles, formal process and supporting system architecture used to produce, collaborate on, maintain ,publish & distribute to the web.

Web Content:

•                     Any information or data on the web

•                     We must identify the types of content we need to manage & how content assets relate to one another

•                     Role to manage the content

•                     Formal process to manage the workflow based on the roles.

•                     Web Content Management success is investing in information model & Design

Based on the Characteristics of content & Business model:

–   Straight forward from data base to the web

–   Automated, dynamic generation of a web site

–   Managing text files

–   Large volumes of multimedia based collection

–   Newly created Content

–   Legacy data

Components of Content Management Workflow:

•                     Content – Input phase

–   Content Entry

– Content – Repository phase

– Store & Managed

– Content Delivery Phase

– Distributed to web

Creation:

•                     Created by the organization & imported into the content management system

•                     These contents can be created in any format-Word, HTML, SGML & XML

•                     Through directly from data base

•                     XML is the standard format

Database import:

•                     Data may come from the external database within same org or partner organization (ERP)

Legacy Inclusion

•                     Already Existing data. E.g.: journal

•                     In some other format – Conversion is required

Content Repository

•                     Store & Management

Storage:

•                     Database – index, relational (or) object oriented

•                     Database can be stored direction (or) pointing to external pointers

•                     Importing is the methodology

Revision Content – Check in/check out

–   Portion of content can be changed depending on the role

–   Roles are set for each and every author

–   Locking

Version Control

–   Complete body of the content is changed

Content Assembly

–   Analysis of meta data about each contents & assemble them for final web delivery

Content – Delivery phase

•                     Common interface b/w the content & end user must be set

•                     XML – is delivery neutral form

Print rendition

–   Print media

–   XML – XSL – Content

Web Rendition

–   Web output (XML – XSL – O/P)

WAP/Mobile Rendition

–   WAP/WML

Context Syndication

–   Syndication from single body of content to multiple end users

–   Automate the process

–   Example for web document creation – WAPDav

<?xml version=―1.0‖> <D:acl xmlns:D:‖DAV‖>

<D:ace>

<D:principal> <D:href>www.xx.com</D:href> <D:principal>

<D:grant>

<D:privilege>D:read</D:privilege>

<D:privilege>D:write</D:privilege>

</D:grant>

</D:ace>

</D:/acl>