Transcript telematics service

Portable Media Devices
And Implications on Database Design
and Queries
By Mark Zalar
Seminar Outline
• Trends in portable media devices
• Database implications
– Stand-alone devices
– Network of devices
• Examples
– Vehicle navigation
– S-CITI evacuation mapping
• Term project
Portable Media Devices
• They’re everywhere!
– Cell phones
– Mp3 players
– Portable DVD players
– PDAs
– Cameras
– Video games
– Vehicle navigation systems
Portable Media Devices
• Trends
– Decrease in size
– Decrease in price
– Increase in features
Trends: Cell Phones
• Remember the car phone?
• First cellular phones
– Voice calls
• Now
– Voice calls
– Text messaging
– Picture messaging
– Video with sound
Trends: Cell Phones
• Other features now available
– Email
– GPS
– Bluetooth
– Sophisticated ring tones
– Games
– Calendars
– Calculators
– Etc.
Trends: mp3 Players
• iPod
– Decrease in size
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1G……………4.02” x 2.43” x 0.78” 6.50 oz.
5G……………4.10” x 2.40” x 0.55” 5.50 oz.
Nano…………3.50” x 1.60” x 0.26” 1.41 oz.
Shuffle……….1.07” x 1.62” x 0.41” 0.55 oz.
Trends: mp3 Players
• iPod
– Increase in number of features
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Video
Pictures
Games
Improved battery life (up to 20 hrs.)
More storage space (up to 80 GB)
Search feature
Trends: mp3 Players
• iPod
– Decrease in price
• 1G (2001-2002)
– $399 5GB
– $499 10GB
• 5G
– $349 30GB
– $449 80GB
What Does It All Mean?
• Decrease in size
– More portability
• Decrease in price
– More accessibility
• Increase in number of features
– More ability
What Does It All Mean?
• Driving advances in technology
– Improved audio and video compression
techniques
– Improved battery performance
– Higher capacity storage devices
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
What Does It All Mean?
• Incredible convenience
– Driving directions
– Scheduling & organization
– Social networking
– Entertainment
– Save time!
Database Implications
• Stand-alone devices
– Device-database interaction
– Querying within a device
• Network of devices
– Concurrency issues
– Dynamic querying
Database Implications
• Stand-alone devices
– Portable multimedia devices often hold data
– Where does this data come from?
– How can this data be managed?
Device-db Interaction
• Synchronization
– Mobile device -> 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
Podcasts
Querying Within A Device
• More storage capacity means more data
• Cell Phones
– Search contacts
• iPod
– search feature
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?
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
Concurrency
• Mobile networks are not as efficient or
reliable
– Interference
– Signal strength
– Ad-hoc wireless networks may suffer from
partitions
Dynamic Querying
• Exact data isn’t always available
– Predictors sometimes necessary
• Multiple data sources
– Querying may not be limited to one data
source
– Mobile distributed data system
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 vehicle’s onboard electronics
– Provide safety, convenience, vehicle
diagnostics, and entertainment
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
Navigation Systems
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!
Navigation Systems: Queries
• Dynamic Query Example 1
– “Where am I?”
• Ask the GPS satellites
– Not always!
• Use predictors to figure it out
– Gyroscope+speedometer+last known position
Navigation Systems: Queries
• Dynamic Query Example 2
– “How do I get from here to there?”
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Determine position
Consult digital map
Listen to TMC
Revise route if necessary
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.
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 SCITI can display that information appropriately.
• From S-CITI project website
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
S-CITI: Evacuation Mapping
• Check in
– User checks in when they enter a room
– Centralized server keeps track of everyone’s
location
– Hazardous event location known
– All users given map to exit
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
S-CITI: Evacuation Mapping
• Dynamic querying
– People’s locations will vary and may change
constantly
– Location of hazardous event will vary and can
change constantly
Improving Clustering Search
Interfaces
By
Mark Zalar
&
Perry Rajnovic
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
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
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