Portable Media Devices

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Portable Media Devices

• And Implications on Database Design and Queries
• By Mark Zalar

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Seminar Outline

• Trends in portable media devices
• Database implications
• Stand-alone devices
• Network of devices
• Examples
• Vehicle navigation
• S-CITI evacuation mapping
• Term project

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Portable Media Devices

• Theyre everywhere!
• Cell phones
• Mp3 players
• Portable DVD players
• PDAs
• Cameras
• Video games
• Vehicle navigation systems

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Portable Media Devices

• Trends
• Decrease in size
• Decrease in price
• Increase in features

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Trends Cell Phones

• Remember the car phone?
• First cellular phones
• Voice calls
• Now
• Voice calls
• Text messaging
• Picture messaging
• Video with sound

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Trends Cell Phones

• Other features now available
• Email
• GPS
• Bluetooth
• Sophisticated ring tones
• Games
• Calendars
• Calculators
• Etc.

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Trends mp3 Players

• iPod
• Decrease in size
• 1G4.02 x 2.43 x 0.78 6.50 oz.
• 5G4.10 x 2.40 x 0.55 5.50 oz.
• Nano3.50 x 1.60 x 0.26 1.41 oz.
• Shuffle.1.07 x 1.62 x 0.41 0.55 oz.

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Trends mp3 Players

• iPod
• Increase in number of features
• Video
• Pictures
• Games
• Improved battery life (up to 20 hrs.)
• More storage space (up to 80 GB)
• Search feature

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Trends mp3 Players

• iPod
• Decrease in price
• 1G (2001-2002)
• 399 5GB
• 499 10GB
• 5G
• 349 30GB
• 449 80GB

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What Does It All Mean?

• Decrease in size
• More portability
• Decrease in price
• More accessibility
• Increase in number of features
• More ability

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What Does It All Mean?

• Driving advances in technology
• Improved audio and video compression techniques
• Improved battery performance
• Higher capacity storage devices

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What Does It All Mean?

• Increased communication among people
• Almost everyone has a cell phone!
• Podcasts
• Web 2.0 ideology
• Ability to get news and other information in new
  settings
• list of free academic Podcasts

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What Does It All Mean?

• Incredible convenience
• Driving directions
• Scheduling organization
• Social networking
• Entertainment
• Save time!

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Database Implications

• Stand-alone devices
• Device-database interaction
• Querying within a device
• Network of devices
• Concurrency issues
• Dynamic querying

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Database Implications

• Stand-alone devices
• Portable multimedia devices often hold data
• Where does this data come from?
• How can this data be managed?

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Device-db Interaction

• Synchronization
• Mobile device -gt immobile, central db
• Mobile device is a version of the central db
• Changes are made to the central db
• Mobile device synchs with central db for updated
  data
• Examples
• iPod iTunes
• Podcasts
• GCALSYNC

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Podcasts
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Querying Within A Device

• More storage capacity means more data
• Cell Phones
• Search contacts
• iPod
• search feature

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Database Implications

• Network of devices
• Many portable multimedia devices communicate via
  wireless networks
• Data is shared among nodes in the network
• How can we be sure the data is accurate?
• How do we access this data?

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Concurrency

• Data concurrency is harder to maintain in mobile
  distributed real-time database systems
• Data is constantly changing
• How much error can be tolerated?
• Examples location, speed, temperature

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Concurrency

• Mobile networks are not as efficient or reliable
• Interference
• Signal strength
• Ad-hoc wireless networks may suffer from
  partitions

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Dynamic Querying

• Exact data isnt always available
• Predictors sometimes necessary
• Multiple data sources
• Querying may not be limited to one data source
• Mobile distributed data system

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Example Navigation Systems

• Telemantics service
• Becoming more common in new vehicles
• Telemantics telecommunication informatics
• Provides information to a mobile source
• Often combine GPS and cellular technology with
  vehicles onboard electronics
• Provide safety, convenience, vehicle diagnostics,
  and entertainment

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Navigation Systems

• How they work
• GPS
• 24 GPS satellites orbiting Earth
• GPS receiver determines its distance from at
  least 3 overheard satellites
• Trigonometry used to calculate latitude and
  longitude
• Gyroscope
• Directional information
• Map matching
• Speedometer
• Map matching
• Digital Map
• Algorithms used to determine route

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Navigation Systems
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VDO Dayton Navigation System

• Special Feature Traffic Message Channel
  Capabilities
• Receives real-time traffic information by FM band
  using RDS (Radio Data System)
• Alerts the driver verbally and visually of
  upcoming traffic issues
• Gives driver option to bypass traffic delay, and
  will calculate new best route!

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Navigation Systems Queries

• Dynamic Query Example 1
• Where am I?
• Ask the GPS satellites
• Not always!
• Use predictors to figure it out
• Gyroscopespeedometerlast known position

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Navigation Systems Queries

• Dynamic Query Example 2
• How do I get from here to there?
• Determine position
• Consult digital map
• Listen to TMC
• Revise route if necessary

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Navigation Systems DB Design

• Digital map acts as the database
• Flexibility!
• Stored on CD/DVD, flash memory, hard disk, or
  some combination
• Common for a base map to be stored in ROM which
  can then be augmented with more detailed
  information for desired locations
• Detailed information can come from CD/DVD, memory
  card, downloaded, etc.

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S-CITI

• Mission
• The Self-secure and robust Critical Information
  Technology Infrastructure project (S-CITI for
  short) aims at providing support to Emergency
  Managers (EMs) that are faced with management of
  resources and with decisions before, during, and
  after emergencies or disasters.
• Approach
• We will use new and existing sensors to gather
  data from the field, process this data to detect
  and predict emergency/disaster situations, and
  disseminate this data among the appropriate
  organizational units. The data flow will be done
  in a reliable and secure manner and EMs will
  coordinate actions in a Virtual Coordination
  Center, which need not be in a fixed (and thus
  vulnerable) physical location. The EMs are
  responsible for indicating what type of data is
  more valuable, so that S-CITI can display that
  information appropriately.
• From S-CITI project website

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S-CITI Evacuation Mapping

• Motivation
• Rescuers often are not familiar with building
  layout
• Building occupants may panic or become
  disoriented during an emergency
• Both rescuers and occupants can easily carry a
  portable multimedia device, like a PDA, to send
  and receive wireless communication

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S-CITI Evacuation Mapping

• Check in
• User checks in when they enter a room
• Centralized server keeps track of everyones
  location
• Hazardous event location known
• All users given map to exit

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S-CITI Evacuation Mapping

• Position determination
• Wireless device determines its location from the
  base station based on signal strength
• Not constrained to rooms
• User does not have to check in

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S-CITI Evacuation Mapping

• Dynamic querying
• Peoples locations will vary and may change
  constantly
• Location of hazardous event will vary and can
  change constantly

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Improving Clustering Search Interfaces

• By
• Mark Zalar
• Perry Rajnovic

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Project Goal

• Implement a search site with a highly usable
  interface for query refinement
• Backend
• Clustering technique to allow for easy refocusing
  of search topics
• Frontend
• AJAX for flexibility

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Backend Design

• Database design
• MySQL implementation
• Clustering mechanism
• Interface between database and frontend
• Glue code between frontend and backend
• PHP and JavaScript code to talk to database

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Backend Design

• Focus on query refinement
• Goal to design database in such a way that query
  refinement is relatively simple
• Clustering hierarchy
• Refinement based on cluster level
• Measures of similarity
• Refinement based on level of similarity