This document outlines and discusses several emerging database technologies including mobile databases, multimedia databases, and geographic information systems (GIS). It describes some of the key characteristics and challenges of managing data in mobile and wireless environments, as well as issues related to modeling, storing, querying, and retrieving multimedia and spatial data types. Examples of applications that utilize these different database technologies are also provided.
Mobile Database Portabledevices 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. Talal A. Alsubaie
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. Mobile Database Talal A. Alsubaie
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Characteristics of MobileEnvironments Communication latency Intermittent connectivity Limited battery life Changing client location All of these Characteristics impact data management in mobile computing. Talal A. Alsubaie
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Characteristics of MobileEnvironments (2) 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. Talal A. Alsubaie
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Characteristics of MobileEnvironments (3) 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. Talal A. Alsubaie
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Client mobility alsoposes 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. Talal A. Alsubaie Characteristics of Mobile Environments (4)
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Data Management IssuesMobile databases can be distributed under two possible scenarios: The entire database is distributed mainly among the wired components, possibly with full or partial replication. Management is done in fixed hosts, with additional functionalities. The database is distributed among wired and wireless components. Management is done in both fixed hosts and mobile units. Talal A. Alsubaie
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Data Management IssuesData 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 Talal A. Alsubaie
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Application: Intermittently SynchronizedDatabases 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. Talal A. Alsubaie
Multimedia Databases Inthe years ahead multimedia information systems are expected to dominate our daily lives. Talal A. Alsubaie
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Nature of MultimediaData 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. … Talal A. Alsubaie
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Nature of MultimediaApplications 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. Talal A. Alsubaie
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Data Management IssuesMultimedia 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. Talal A. Alsubaie
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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). Talal A. Alsubaie
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Data Management Issues(cont.) Talal A. Alsubaie 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 ApplicationsDocuments and records management Knowledge dissemination Education and training Marketing, advertising, retailing, entertainment, and travel Real-time control and monitoring Talal A. Alsubaie
Geographic Information SystemsGeographic information systems(GIS): A systematic integration of hardware and software for capturing, storing, displaying, updating manipulating and analyzing spatial data . Talal A. Alsubaie
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title GIS canbe 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 Talal A. Alsubaie Geographic Information Systems
Characteristics of Datain GIS There are several aspects of the geographical objects need to be considered: Location. Temporality. Complex Spatial Features. Object ID. Data Quality. … Talal A. Alsubaie
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Characteristics of Datain GIS The geographic context, topologic relations and other spatial relationships are fundamentally important in order to define spatial integrity rules . Talal A. Alsubaie
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Constraints in GISTopology 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 . Talal A. Alsubaie
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Conceptual Data Modelsfor 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. Talal A. Alsubaie
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Conceptual Data Modelsfor 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. Talal A. Alsubaie
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DBMS Enhancements forGIS 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. Talal A. Alsubaie
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GIS Standers andOperations Spatial Relationship Standard: Equal. Intersect. Touch. Cross. Within. … and more. Talal A. Alsubaie
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GIS Standers andOperations 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. And more. Talal A. Alsubaie
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GIS Standers andOperations CREATE TABLE STATES ( Sname VARCHAR(50 ) NOT NULL , State_shape POLYGON NOT NULL , Country VARCHAR(50 ) NOT NULL , PRIMARY KEY (Sname), FOREIGN KEY (Country) REFERENCES COUNTRIES (Cname) ); SELECT Sname FROM STATS WHERE ( AREA (State_shape) > 50000) Talal A. Alsubaie
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Future of GISThere are some challenges in developing GIS applications: Data Source. Data Model. Standards. Mobile GIS. Specialized DBMS for GIS. … Talal A. Alsubaie