Building Trustworthy Semantic Webs

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Building Trustworthy Semantic Webs

• Dr. Bhavani Thuraisingham
• The University of Texas at Dallas
• Lecture 3
• Supporting Technologies Databases, Information
  Management and Information Security
• August 2006

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Database System

• Consists of database, hardware, Database
  Management System (DBMS), and users
• Database is the repository for persistent data
• Hardware consists of secondary storage volumes,
  processors, and main memory
• DBMS handles all users access to the database
• Users include application programmers, end users,
  and the Database Administrator (DBA)
• Need Reduced redundancy, avoids inconsistency,
  ability to share data, enforce standards, apply
  security restrictions, maintain integrity,
  balance conflicting requirements
• We have used the definition of a database
  management system given in C. J. Dates Book
  (Addison Wesley, 1990)

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An Example Database System
Adapted from C. J. Date, Addison Wesley, 1990
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Metadata

• Metadata describes the data in the database
• Example Database D consists of a relation EMP
  with attributes SS, Name, and Salary
• Metadatabase stores the metadata
• Could be physically stored with the database
• Metadatabase may also store constraints and
  administrative information
• Metadata is also referred to as the schema or
  data dictionary

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Functional Architecture
Data Management
User Interface Manager
Schema (Data Dictionary) Manager (metadata)
Security/ Integrity Manager
Query Manager
Transaction Manager
Storage Management
File Manager
Disk Manager
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DBMS Design Issues

• Query Processing
• Optimization techniques
• Transaction Management
• Techniques for concurrency control and recovery
• Metadata Management
• Techniques for querying and updating the
  metadatabase
• Security/Integrity Maintenance
• Techniques for processing integrity constraints
  and enforcing access control rules
• Storage management
• Access methods and index strategies for efficient
  access to the database

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Relational Database Example
Relation S S SNAME STATUS CITY S1 Smith
20 London S2 Jones 10
Paris S3 Blake 30
Paris S4 Clark 20 London S5
Adams 30 Athens Relation P P
PNAME COLOR WEIGHT CITY P1 Nut
Red 12 London P2 Bolt
Green 17 Paris P3 Screw
Blue 17 Rome P4 Screw
Red 14 London P5 Cam
Blue 12 Paris P6 Cog
Red 19 London
Relation SP S P QTY S1 P1
300 S1 P2 200 S1 P3 400 S1 P4
200 S1 P5 100 S1 P6 100 S2
P1 300 S2 P2 400 S3 P2
200 S4 P2 200 S4 P4 300 S4 P5
400
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Concepts in Object Database Systems

• Objects- every entity is an object
• Example Book, Film, Employee, Car
• Class
• Objects with common attributes are grouped into a
  class
• Attributes or Instance Variables
• Properties of an object class inherited by the
  object instances
• Class Hierarchy
• Parent-Child class hierarchy
• Composite objects
• Book object with paragraphs, sections etc.
• Methods
• Functions associated with a class

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A Definition of a Distributed Database System

• A collection of database systems connected via a
  network
• The software that is responsible for
  interconnection is a Distributed Database
  Management System (DDBMS)
• Each DBMS executes local applications and should
  be involved in at least one global application
  (Ceri and Pelagetti)
• Homogeneous environment

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Architecture
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Data Distribution
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Interoperability of Heterogeneous Database Systems
Database System A
Database System B
(Relational)
(Object- Oriented)
Network
Transparent access to heterogeneous databases -
both users and application programs Query,
Transaction processing
Database System C (Legacy)
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Federated Database Management
Database System A
Database System B
Federation F1
Cooperating database systems yet maintaining some
degree of autonomy
Federation F2
Database System C
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Federated Data and Policy Management
Data/Policy for Federation
Export
Export
Data/Policy
Data/Policy
Export
Data/Policy
Component
Component
Data/Policy for
Data/Policy for
Agency A
Agency C
Component
Data/Policy for
Agency B
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Current Status and Directions

• Developments
• Several prototypes and some commercial products
• Tools for schema integration and transformation
• Standards for interoperable database systems
• Challenges being addressed
• Semantic heterogeneity
• Autonomy and federation
• Global transaction management
• Integrity and Security
• New challenges
• Scale
• Web data management

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What is Information Management?

• Information management essentially analyzes the
  data and makes sense out of the data
• Several technologies have to work together for
  effective information management
• Data Warehousing Extracting relevant data and
  putting this data into a repository for analysis
• Data Mining Extracting information from the data
  previously unknown
• Multimedia managing different media including
  text, images, video and audio
• Web managing the databases and libraries on the
  web

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Data Warehouse
Data Warehouse Data correlating Employees
With Medical Benefits and Projects
Could be any DBMS Usually based on the
relational data model
Users Query the Warehouse
Oracle DBMS for Employees
Sybase DBMS for Projects
Informix DBMS for Medical
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Multidimensional Data Model
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Data Mining
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Multimedia Information Management
Broadcast News Editor (BNE)
Video Source
Broadcast News Navigator (BNN)
Correlation
Scene Change Detection
Story GIST Theme
Broadcast Detection
Frame Classifier
Key Frame Selection
Commercial Detection
Imagery
Silence Detection
Story Segmentation
Multimedia Database Management System
Audio
Speaker Change Detection
Closed Caption Text
Token Detection
Named Entity Tagging
Closed Caption Preprocess
Web-based Search/Browse by Program, Person,
Location, ...
Segregate Video Streams
Analyze and Store Video and Metadata
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Extracting Relations from Text for Mining An
Example
Goal FindCooperating/Combating Leadersin a
territory
AssociationRule Product
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Image ProcessingExample Change Detection

• Trained Neural Network to predict new pixel
  from old pixel
• Neural Networks good for multidimensional
  continuous data
• Multiple nets gives range of expected values
• Identified pixels where actual value
  substantially outside range of expected values
• Anomaly if three or more bands (of seven) out of
  range
• Identified groups of anomalous pixels

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Semantic Web

• Adapted from Tim Berners Lees description of the
  Semantic Web

• Some Challenges Interoperability between
  Layers Security and Privacy cut across all
  layers Integration of Services Composability

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Semantic Web Technologies

• Web Database/Information Management
• Information retrieval and Digital Libraries
• XML, RDF and Ontologies
• Representation information
• Information Interoperability
• Integrating heterogeneous data and information
  sources
• Intelligent agents
• Agents for locating resources, managing
  resources, querying resources and understanding
  web pages
• Semantic Grids
• Integrating semantic web with grid computing
  technologies

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Information Management for Collaboration
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Some Emerging Information Management Technologies

• Visualization
• Visualization tools enable the user to better
  understand the information
• Peer-to-Peer Information Management
• Peers communicate with each other, share
  resources and carry out tasks
• Sensor and Wireless Information Management
• Autonomous sensors cooperating with one another,
  gathering data, fusing data and analyzing the
  data
• Integrating wireless technologies with semantic
  web technologies

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What is Knowledge Management?

• Knowledge management, or KM, is the process
  through which organizations generate value from
  their intellectual property and knowledge-based
  assets
• KM involves the creation, dissemination, and
  utilization of knowledge
• Reference http//www.commerce-database.com/knowle
  dge-management.htm?sourcegoogle

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Knowledge Management Components
Knowledge
Components of
Management
Components,
Cycle and
Technologies
Cycle
Technologies
Components
Knowledge, Creation
Expert systems
Strategies
Sharing, Measurement
Collaboration
Processes
And Improvement
Training
Metrics
Web
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Organizational Learning Process
Incentives
Source Reinhardt and Pawlowsky
also see Tools in Organizational
Learning http//duplox.wz-berlin.de/oldb/forslin.h
tml
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Operating System Security

• Access Control
• Subjects are Processes and Objects are Files
• Subjects have Read/Write Access to Objects
• E.g., Process P1 has read acces to File F1 and
  write access to File F2
• Capabilities
• Processes must presses certain Capabilities /
  Certificates to access certain files to execute
  certain programs
• E.g., Process P1 must have capability C to read
  file F

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Mandatory Security

• Bell and La Padula Security Policy
• Subjects have clearance levels, Objects have
  sensitivity levels clearance and sensitivity
  levels are also called security levels
• Unclassified lt Confidential lt Secret lt TopSecret
• Compartments are also possible
• Compartments and Security levels form a partially
  ordered lattice
• Security Properties
• Simple Security Property Subject has READ access
  to an object of the subjects security level
  dominates that of the objects
• Star () Property Subject has WRITE access to an
  object if the subjects security level is
  dominated by that of the objects\

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Covert Channel Example

• Trojan horse at a higher level covertly passes
  data to a Trojan horse at a lower level
• Example
• File Lock/Unlock problem
• Processes at Secret and Unclassified levels
  collude with one another
• When the Secret process lock a file and the
  Unclassified process finds the file locked, a 1
  bit is passed covertly
• When the Secret process unlocks the file and the
  Unclassified process finds it unlocked, a 1 bit
  is passed covertly
• Over time the bits could contain sensitive data

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Network Security

• Security across all network layers
• E.g., Data Link, Transport, Session,
  Presentation, Application
• Network protocol security
• Ver5ification and validation of network protocols
• Intrusion detection and prevention
• Applying data mining techniques
• Encryption and Cryptography
• Access control and trust policies
• Other Measures
• Prevention from denial of service, Secure
  routing, - - -

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Steps to Designing a Secure System

• Requirements, Informal Policy and model
• Formal security policy and model
• Security architecture
• Identify security critical components these
  components must be trusted
• Design of the system
• Verification and Validation

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Product Evaluation

• Orange Book
• Trusted Computer Systems Evaluation Criteria
• Classes C1, C2, B1, B2, B3, A1 and beyond
• C1 is the lowest level and A1 the highest level
  of assurance
• Formal methods are needed for A1 systems
• Interpretations of the Orange book for Networks
  (Trusted Network Interpretation) and Databases
  (Trusted Database Interpretation)
• Several companion documents
• Auditing, Inference and Aggregation, etc.
• Many products are now evaluated using the federal
  Criteria

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Security Threats to Web/E-commerce
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Approaches and Solutions

• End-to-end security
• Need to secure the clients, servers, networks,
  operating systems, transactions, data, and
  programming languages
• The various systems when put together have to be
  secure
• Composable properties for security
• Access control rules, enforce security policies,
  auditing, intrusion detection
• Verification and validation
• Security solutions proposed by W3C and OMG
• Java Security
• Firewalls
• Digital signatures and Message Digests,
  Cryptography

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Other Security Technologies

• Data and Applications Security
• Middleware Security
• Insider Threat Analysis
• Risk Management
• Trust and Economics
• Biometrics