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 • 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 • 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
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
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?” • 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 S-CITI 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 • 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