Mobile Database <ul><li>Prepared by  </li></ul><ul><li>Ali M. Alrazgi   </li></ul><ul><li>Supervisor  </li></ul><ul><li>Dr...
<ul><li>Wireless Characteristics  </li></ul><ul><li>Mobile Computing Architecture  </li></ul><ul><li>Mobile Problems . </l...
Wireless  Characteristics <ul><li>Data Rates. </li></ul><ul><li>Range. </li></ul><ul><li>Interference. </li></ul><ul><li>S...
<ul><li>Goal :  Access Information Anywhere, Anytime, and in Any Way. </li></ul><ul><li>Aliases:   Mobile, Nomadic, Wirele...
Mobile Computing Architecture Infrastructure-based mobile platform A general architecture of an infrastructure-based mobil...
<ul><li>Mobile Ad-Hoc Network (MANET): </li></ul><ul><ul><li>In a  MANET , mobile units do not need to communicate via a f...
<ul><li>MANET can fall under Peer-to-Peer  architecture . </li></ul><ul><li>Peer-to-Peer :   means  that mobile units is s...
Mobile Problems <ul><li>Software  problems </li></ul><ul><ul><li>Data management </li></ul></ul><ul><ul><li>Query & Transa...
Characteristics of Mobile Environments <ul><li>High communication latency   </li></ul><ul><ul><li>Latency : </li></ul></ul...
Characteristics of Mobile Environments     cont <ul><li>To compensate for high latencies and unreliable connectivity   </l...
Data Management  <ul><li>MDB can be distributed under two possible scenarios:   </li></ul><ul><ul><ul><li>The entire datab...
Transaction & Query  processing Query  processing Pull/push  mechanism Pull-operation Push-operation (Broadcast Strategy) ...
Transaction & Query  processing <ul><li>Pull:  PDAs  demand , servers  respond   </li></ul><ul><li>Pull operation:   mobil...
Transaction & Query  processing <ul><li>Push operation (on-demand broadcast) </li></ul><ul><ul><ul><ul><li>send queries th...
Push operation (on-demand broadcast ) Mobile Client Query  Broadcast Channel  Query  Query  Query  Result   Result Result ...
Broadcast Approach  <ul><li>Broadcasting:  It is the process in which one node sends a packet to all other nodes in the ne...
Transaction & Query  processing periodic broadcast <ul><li>Push operation (periodic broadcast):   Refers to periodically b...
Push operation (periodic broadcast) cont <ul><li>Main challenge : </li></ul><ul><ul><li>minimize query response time (redu...
Transaction models <ul><ul><li>Transaction models:   A   mobile transaction is executed sequentially through several BS an...
Mobile database design <ul><li>Mobile database design </li></ul><ul><ul><ul><ul><li>Only the most frequently used data sho...
Mobile database design. <ul><li>Synchronization and </li></ul><ul><li>Conflict Resolution </li></ul><ul><li>Easy Synchroni...
Database Recovery <ul><li>Mobile Database System Recovery Process  :  is a mechanism to restore an intermediate consistent...
References <ul><li>Elmasri/Navathe  ‘Mobile Database’ Ch 30 </li></ul><ul><li>Agustinus Borgy Waluyo , Bala Srinivasana an...
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Mobile Database ,alrazgi

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Mobile Database ,alrazgi

  1. 1. Mobile Database <ul><li>Prepared by </li></ul><ul><li>Ali M. Alrazgi </li></ul><ul><li>Supervisor </li></ul><ul><li>Dr. Hassan Najadat </li></ul>
  2. 2. <ul><li>Wireless Characteristics </li></ul><ul><li>Mobile Computing Architecture </li></ul><ul><li>Mobile Problems . </li></ul><ul><li>Characteristics of Mobile Environments </li></ul><ul><li>Data Management Issues </li></ul>
  3. 3. Wireless Characteristics <ul><li>Data Rates. </li></ul><ul><li>Range. </li></ul><ul><li>Interference. </li></ul><ul><li>Support for packet switching . </li></ul><ul><li>locality of access </li></ul><ul><li>Seamless roaming (Phone ). </li></ul><ul><li>Wi-Fi , Bluetooth :use unlicensed frequency . </li></ul><ul><ul><ul><ul><ul><li>Interference </li></ul></ul></ul></ul></ul>
  4. 4. <ul><li>Goal : Access Information Anywhere, Anytime, and in Any Way. </li></ul><ul><li>Aliases: Mobile, Nomadic, Wireless, Pervasive, Invisible </li></ul><ul><li>Distinction: </li></ul><ul><ul><ul><ul><li>Fixed wired network: Traditional distributed computing. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Fixed wireless network: Wireless computing. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Wireless network: Mobile Computing. </li></ul></ul></ul></ul><ul><li>Applications: </li></ul><ul><ul><ul><ul><li>Vertical : tracking , point of sales </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Horizontal : mail application , filter information provision </li></ul></ul></ul></ul><ul><ul><ul><ul><li>new massive markets in conjunction with the Web </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mobile Information Appliances - combining personal computing and consumer electronics </li></ul></ul></ul></ul>Mobile and Wireless Computing & applications
  5. 5. Mobile Computing Architecture Infrastructure-based mobile platform A general architecture of an infrastructure-based mobile platform high-speed wired network Base Station Base Station Base Station Wireless LAN Cell 2kbps - 15 mbps Wireless Radio Cell 9kbps-14 kbps Wireless Ethernet Cell Mbps - Gbps
  6. 6. <ul><li>Mobile Ad-Hoc Network (MANET): </li></ul><ul><ul><li>In a MANET , mobile units do not need to communicate via a fixed network such as Bluetooth. </li></ul></ul><ul><ul><li>In a MANET , mobile units are responsible for routing their own data </li></ul></ul><ul><ul><li>MANET must be robust enough to handle changes in network topology. </li></ul></ul><ul><ul><ul><li>Such as arrival or departure of mobile unites. </li></ul></ul></ul><ul><li>Sample applications for MANET application </li></ul><ul><ul><ul><ul><li>Multi-user games </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Battle information sharing </li></ul></ul></ul></ul><ul><ul><ul><ul><li>shared whiteboards, </li></ul></ul></ul></ul><ul><ul><ul><ul><li>distributed calendars, </li></ul></ul></ul></ul><ul><li>Characteristics of (MANET): </li></ul><ul><ul><li>Frequent disconnections. </li></ul></ul><ul><ul><li>Frequent network partitions. </li></ul></ul><ul><ul><li>Centralized control is difficult . </li></ul></ul><ul><ul><li>Peer Heterogeneity. </li></ul></ul>Mobile Computing Architecture: Infrastructure-less Mobile Platform (MANET )
  7. 7. <ul><li>MANET can fall under Peer-to-Peer architecture . </li></ul><ul><li>Peer-to-Peer : means that mobile units is simultaneously a client and server . </li></ul><ul><li>Kinds of Peer-to –Peer : </li></ul><ul><ul><ul><ul><li>Hybrid P2P Network : Central server can provide the information to all peers (Napster) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Fully p2p network : No central servers </li></ul></ul></ul></ul><ul><li>First generation : routing and querying through broadcasting , </li></ul><ul><li>Causing flooding in the network . </li></ul><ul><li>Second generation : routing and querying are based on distributed hash tables </li></ul>Mobile Computing Architecture:
  8. 8. Mobile Problems <ul><li>Software problems </li></ul><ul><ul><li>Data management </li></ul></ul><ul><ul><li>Query & Transaction processing </li></ul></ul><ul><ul><li>Security </li></ul></ul><ul><ul><li>Transaction management </li></ul></ul><ul><ul><li>Database recovery </li></ul></ul><ul><li>Hardware problems are more difficult. </li></ul><ul><ul><li>Limited & intermittent of Connectivity . </li></ul></ul><ul><ul><li>Battery Life . </li></ul></ul><ul><ul><li>Changes in network topology. </li></ul></ul><ul><ul><li>Wireless Transmission Speed. </li></ul></ul>
  9. 9. Characteristics of Mobile Environments <ul><li>High communication latency </li></ul><ul><ul><li>Latency : </li></ul></ul><ul><ul><ul><ul><li>Increases the time to service each client request </li></ul></ul></ul></ul><ul><ul><ul><ul><li>The server can handle fewer clients. </li></ul></ul></ul></ul><ul><li>broadcasting data whenever possible </li></ul><ul><li>Intermittent wireless connectivity </li></ul><ul><ul><ul><ul><li>unIntentional :signals cannot reach, </li></ul></ul></ul></ul><ul><ul><ul><ul><li>intentional :takeoff of an airplane prerogatives </li></ul></ul></ul></ul><ul><li>limited battery life </li></ul><ul><li>Changing client location </li></ul>
  10. 10. Characteristics of Mobile Environments cont <ul><li>To compensate for high latencies and unreliable connectivity </li></ul><ul><ul><ul><ul><li>Caching frequently used data on the mobile device. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Increasing data availability and response time </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Organize data by using the Cluster </li></ul></ul></ul></ul><ul><ul><li>A client may be unreachable because handoff </li></ul></ul><ul><ul><ul><ul><ul><li>Proxies for unreachable (proxy can cache updates intended for the server </li></ul></ul></ul></ul></ul><ul><li>Proxy automatically forwards these cached updates to their ultimate destination </li></ul>
  11. 11. Data Management <ul><li>MDB can be distributed under two possible scenarios: </li></ul><ul><ul><ul><li>The entire database is distributed mainly among the wired components </li></ul></ul></ul><ul><ul><ul><ul><ul><li>A base station or fixed host manages its own database </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>query and transaction management of mobile environments. </li></ul></ul></ul></ul></ul><ul><ul><ul><li>The database is distributed among wired and wireless components </li></ul></ul></ul><ul><ul><ul><ul><ul><li>Data management responsibility is shared among BS or FH and mobile units. </li></ul></ul></ul></ul></ul><ul><li>Additional considerations and variations: </li></ul><ul><ul><ul><ul><ul><li>Query processing. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Data distribution and replication. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Transaction models. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Recovery and backup. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Mobile database design. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Location based service. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Division of labor. </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Security </li></ul></ul></ul></ul></ul>
  12. 12. Transaction & Query processing Query processing Pull/push mechanism Pull-operation Push-operation (Broadcast Strategy) On-Demand Broadcast Periodic Broadcast <ul><li>Query processing: Awareness of where the data is located is important and affects the cost/benefit analysis of query processing </li></ul>
  13. 13. Transaction & Query processing <ul><li>Pull: PDAs demand , servers respond </li></ul><ul><li>Pull operation: mobile clients establish </li></ul><ul><li>a connection with the server via a dedicated link or channel. </li></ul><ul><li>poor match for asymmetric communication </li></ul><ul><li>Limitation of Resource preservation is of the utmost importance </li></ul>Query Query Result Result
  14. 14. Transaction & Query processing <ul><li>Push operation (on-demand broadcast) </li></ul><ul><ul><ul><ul><li>send queries through dedicated channel, monitors to retrieve result. </li></ul></ul></ul></ul><ul><li>very large number of request initiated by clients </li></ul><ul><li>The queries are processed in a group </li></ul><ul><li>Broadcast is the increase of bandwidth when the client sends the request to the server. </li></ul><ul><li>The congested channel which that affect on query </li></ul><ul><li>performance and power consumption of mobile clients. </li></ul>
  15. 15. Push operation (on-demand broadcast ) Mobile Client Query Broadcast Channel Query Query Query Result Result Result <ul><ul><ul><ul><li>Send queries through dedicated channel, monitors to retrieve result. </li></ul></ul></ul></ul><ul><li>very large number of request initiated by clients </li></ul>
  16. 16. Broadcast Approach <ul><li>Broadcasting: It is the process in which one node sends a packet to all other nodes in the network . </li></ul><ul><li>Broadcast Approach : </li></ul><ul><ul><li>Flat : broadcast the union of the requested data cyclic </li></ul></ul><ul><ul><li>Skewed : broadcast different items with different frequencies </li></ul></ul><ul><li>Broadcast : well reduces the load on the server, as clients do not have to maintain active connections to it. </li></ul>C B A C A A C B A C B A A
  17. 17. Transaction & Query processing periodic broadcast <ul><li>Push operation (periodic broadcast): Refers to periodically broadcast database </li></ul><ul><li>One or more broadcast channels, a mobile client capture and select data items which it interested in. </li></ul><ul><li>Access to data is sequential. </li></ul>
  18. 18. Push operation (periodic broadcast) cont <ul><li>Main challenge : </li></ul><ul><ul><li>minimize query response time (reduce the length of broadcast cycles.) </li></ul></ul><ul><ul><ul><li>Selection of Data Items to be Broadcast </li></ul></ul></ul><ul><ul><ul><li>Distribution of Data Items over Multiple Channels (split data) </li></ul></ul></ul><ul><ul><ul><li>Organization of Data items </li></ul></ul></ul>
  19. 19. Transaction models <ul><ul><li>Transaction models: A mobile transaction is executed sequentially through several BS and possibly on multiple data sets depending upon the movement of the MU. </li></ul></ul><ul><li>a mobile transaction is expected to be long-lived because of disconnection in mobile units </li></ul><ul><ul><ul><ul><li>properties of transactions (ACID) : </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Atomicity </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Consistency Preservation </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Isolation </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Durability </li></ul></ul></ul></ul></ul>
  20. 20. Mobile database design <ul><li>Mobile database design </li></ul><ul><ul><ul><ul><li>Only the most frequently used data should be stored </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Minimal the transferred between MU and central-DB </li></ul></ul></ul></ul><ul><li>Division of labor: In some cases, the client must function independent of the server. </li></ul>
  21. 21. Mobile database design. <ul><li>Synchronization and </li></ul><ul><li>Conflict Resolution </li></ul><ul><li>Easy Synchronization </li></ul><ul><li>Deploy Conflict Resolution </li></ul><ul><li>Techniques </li></ul>Mobile Database <ul><li>Responsiveness </li></ul><ul><li>Identify Relevant Data </li></ul><ul><li>Data Summarization </li></ul><ul><li>Data Compression </li></ul><ul><li>Data Caching </li></ul><ul><li>Indexing </li></ul><ul><li>Restricted Connection </li></ul><ul><li>High Availability </li></ul><ul><li>Automatic Backups </li></ul><ul><li>Automatic Recovery </li></ul><ul><li>Data Replication </li></ul><ul><li>Security </li></ul><ul><li>User Authentication </li></ul><ul><li>Data Encryption </li></ul><ul><li>Restrict Access Through </li></ul><ul><li>Roles </li></ul><ul><li>Data Consistency </li></ul><ul><li>And Concurrency </li></ul><ul><li>Manage Online Transaction </li></ul><ul><li>Manage Offline Transaction </li></ul><ul><li>Manage Unplanned </li></ul><ul><li>Disconnection </li></ul><ul><li>Addition Factors </li></ul><ul><li>Data Size </li></ul><ul><li>Screen Size </li></ul><ul><li>Slow Transmission Speed </li></ul><ul><li>Slow Processing Speed </li></ul><ul><li>Cost </li></ul>
  22. 22. Database Recovery <ul><li>Mobile Database System Recovery Process : is a mechanism to restore an intermediate consistent state of the system </li></ul><ul><li>Factors that affect the recovery process: </li></ul><ul><ul><li>Failure rate of the host </li></ul></ul><ul><ul><li>Communication / Mobility Ratio </li></ul></ul><ul><ul><li>Message Size </li></ul></ul><ul><ul><li>Memory constraints </li></ul></ul><ul><ul><li>Recovery time </li></ul></ul><ul><li>Recovery Problem Specifications: </li></ul><ul><ul><li>Location is not fixed </li></ul></ul><ul><ul><li>Disconnection </li></ul></ul><ul><ul><li>Batteries have limited power </li></ul></ul><ul><ul><li>Different types of failures </li></ul></ul><ul><ul><ul><ul><ul><li>Hard failure ( broken or is lost or stolen .) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>soft failure ( memory contents are lost, OS crashes ) </li></ul></ul></ul></ul></ul><ul><ul><li>Random Handoff </li></ul></ul><ul><ul><li>Weak wireless link </li></ul></ul>
  23. 23. References <ul><li>Elmasri/Navathe ‘Mobile Database’ Ch 30 </li></ul><ul><li>Agustinus Borgy Waluyo , Bala Srinivasana and David Taniar ‘Research in mobile database query optimization and processing’ </li></ul><ul><li>Ruchika Dua and Saurabh Bhandari ‘Recovery in Mobile Database System’ </li></ul><ul><li>Weider D . Yu, Tamseela Amjad, Himani Goel, Tanakom Talawat ‘An Approach of Mobile Database Design Methodology for Mobile Software Solutions’ </li></ul>
  24. 24. Thank you for your attention
  25. 25. Questions ?
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