Transcript 1408001538_Emerging-DB

Emerging Database Technologies
and Applications
Outline
 Mobile Database.
 Multimedia Database.
 GIS ( Geographic Information Systems ).
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Mobile Database
Mobile Database
 Portable devices and wireless technology led to mobile computing.
 Portable computing devices and wireless communication allowed the client to
access data from any ware and any time.
 There are some HW and SW problems that must be solved to make maximum
exploitation of mobile computing.
 i.e. Database recovery.
 Hardware problems are more difficult.
 Wireless coverage.
 Battery.
 Changes in network topology.
 Wireless Transmission Speed.
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Mobile Database
• Mobile Computing Architecture:
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Mobile Database
• Mobile Ad-Hoc Network (MANET):
– In a MANET, co-located mobile units do not need to communicate via a fixed
network, but instead, form their own using cost-effective technologies such as
Bluetooth.
– In a MANET, mobile units are responsible for routing their own data,
effectively acting as base stations as well as clients.
– MANET must be robust enough to handle changes in network topology.
• Such as arrival or departure of mobile unites.
– MANET can fall under P2P architecture.
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Characteristics of Mobile Environments
– Communication latency
– Intermittent connectivity
– Limited battery life
– Changing client location
– All of these Characteristics impact data management in mobile
computing.
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Characteristics of Mobile Environments
 The server may not be able to reach the client or vise versa.
 We can add proxies to the client and the server to cache updates
into when connection is not available.
 After the connection is available proxy automatically forward
these updates to its distention.
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Characteristics of Mobile Environments
 The latency involved in wireless communication makes scalability
a problem.
 Since latency increases the time to service each client request, so the server
can handle fewer clients.
 Servers can use Broadcasting to solve this problem.
 Broadcast well reduces the load on the server, as clients do not
have to maintain active connections to it.
 For example weather broadcasting.
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Characteristics of Mobile Environments
 Client mobility also poses many data management challenges:
 Servers must keep track of client locations in order to efficiently route
messages to them.
 Client data should be stored in the network location that minimizes the traffic
necessary to access it.
 The act of moving between cells must be transparent to the client.
 Client mobility also allows new applications that are location-based.
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Data Management Issues
• Mobile databases can be distributed under two possible scenarios:
1. The entire database is distributed mainly among the wired components,
possibly with full or partial replication.
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Management is done in fixed hosts, with additional functionalities.
2.
The database is distributed among wired and wireless components.
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Management is done in both fixed hosts and mobile units.
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Data Management Issues
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Data distribution and replication (Cache)
Transactions models
Query processing (where data is located?)
Recovery and fault tolerance
Mobile database design
Location-based service
Division of labor
Security
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Application: Intermittently Synchronized Databases
 The client has his own application and DBMS in his local laptop.
 Do some updates locally and connect to the server via internet to get batch of
updates (synchronization).
 The primary characteristic of this scenario is that the clients are mostly
disconnected; the server is not necessarily able reach them.
 This environment has problems similar to those in distributed and client-server
databases, and some from mobile databases.
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Application: Intermittently Synchronized Databases
Insert\Update Data
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Multimedia Database
Nature of Multimedia Data and Applications
 DBMSs have been constantly adding to the types of data they
support.
 Today many types of multimedia data are available in current
systems.
 Text.
 Graphics.
 Images.
 Animation.
 Video.
 Audio.
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Nature of Multimedia Applications
 Multimedia data may be stored, delivered, and utilized in many
different ways.
 Applications may be categorized based on their data management
characteristics.
 Repository applications.
 A large amount of multimedia data as well as metadata is stored for retrieval purposes.
 Presentation applications.
 Simple multimedia viewing of video or audio data.
 Collaborative work using multimedia information.
 Which engineers may execute a complex design task by merging drawings, fitting subjects to
design constraints, and generating new documentation, change notifications, and so forth.
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Data Management Issues
 Multimedia applications dealing with thousands of images,
documents, audio and video segments, and free text data
depend critically on:
 Appropriate modeling of the structure and content of data.
 Designing appropriate database schemas for storing and
retrieving multimedia information.
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Data Management Issues (cont.)
 Multimedia information systems are very complex and embrace a
large set of issues:
 Modeling:
 Complex Objects, dealing with large number of types of data
(Graphics).
 Design:
 Conceptual, logical, and physical design of multimedia has not
been addressed fully, and it remains an area of active research.
 Storage:
 Multimedia data on standard disk devices presents problems of
representation, compression, mapping to device hierarchies,
archiving, and buffering during the input/output operation.
 DBMS has presented the BLOB type (Binary Large Object).
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Data Management Issues (cont.)
• Multimedia information systems are very complex and embrace a
large set of issues (cont.):
– Queries and retrieval:
• The database way of retrieving information is based on
query languages and internal index structures.
– Performance :
– Multimedia applications involving only documents and
text, performance constraints are subjectively determined
by the user.
– Applications involving video playback or audio-video
synchronization, physical limitations dominate.
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Multimedia Database Applications
• Documents and records management
• Knowledge dissemination
• Education and training
• Marketing, advertising, retailing, entertainment, and travel
• Real-time control and monitoring
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Geographic Information
Systems (GIS)
Geographic Information Systems
 Geographic information systems(GIS):
 A systematic integration of hardware and software for capturing, storing,
displaying, updating manipulating and analyzing spatial data.
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Geographic Information
Systems
 GIS can be divided into two formats:
 Vector data represents geometric objects such as points, lines, and polygons.
 Raster data is characterized as an array of points, where each point represents
the value of an attribute for a real-world location.
 Informally, raster images are n-dimensional array where each entry is a unit of the
image and represents an attribute
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Geographic Information
Systems
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Characteristics of Data in GIS
 There are several aspects of the geographical objects need
to be considered:
 Location.
 Temporality.
 Complex Spatial Features.
 Object ID.
 Data Quality.
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Characteristics of Data in GIS
 The geographic context, topologic relations and other spatial
relationships are fundamentally important in order to define
spatial integrity rules.
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Constraints in GIS
 Topology Integrity.
 Deals with the behavior of features and the spatial relationship between
them.
 Semantic Integrity.
 Deals with the meaning.
 User Defined Integrity.
 Business rules.
 Temporal.
 Punctual and Durable.
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Conceptual Data Models for GIS
 Briefly describes the common conceptual models for
storing spatial data in GIS.
 Some conceptual data models:
 Raster data model:
 Used for analytical applications.
 Vector data model:
 Analysis is done using a well defined set of tools.
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Conceptual Data Models for GIS
 Some conceptual data models (cont.):
 Network model:
 Define how lines connect to each other in a point.
 Rules are stored in a connectivity table.
 Example of everyday application, optimizing a school bus route.
 TIN data model:
 Triangular Irregular Network.
 Is a vector-based approach.
 models surfaces by connecting sample points as vector
of triangles.
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DBMS Enhancements for GIS
 Until the mid 1990s, GIS system was based mainly on file-based systems.
 No transfer standards was defined, which limited vendors in terms of sharing.
 Involved in a geo-structure and attributes was stored in DBMS.
 The spatial features was kept in a file and linked to the attributes.
 Could not take FULL advantage of commercial RDBMS.
 Database extensions has been released by vendors like DB2 spatial extender, and
OracleSpatial and OracleLocator to support GIS data.
 These extensions allowed the user to store, manage, and retrieve geo-objects.
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GIS Standers and Operations
 Spatial Relationship Standard:
 Equal.
 Intersect.
 Touch.
 Cross.
 Within.
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GIS Standers and Operations
 Spatial Analysis Standard:
 Distance.
 Returns the shortest distance between any two points in two geometries.
 Buffer.
 Returns a geometry that represents all points whose distance from the
given geometry is less than or equal to distance.
 Convex Hull.
 Union.
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GIS Standers and Operations
CREATE TABLE STATES (
Sname
State_shape
Country
VARCHAR(50)
POLYGON
VARCHAR(50)
NOT NULL,
NOT NULL,
NOT NULL,
PRIMARY KEY (Sname),
FOREIGN KEY (Country) REFERENCES COUNTRIES (Cname)
);
SELECT Sname
FROM STATS
WHERE (AREA (State_shape > 50000))
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Future of GIS
 There are some challenges in developing GIS applications:
 Data Source.
 Data Model.
 Standards.
 Mobile GIS.
 Specialized DBMS for GIS.
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