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3.6.2000 R. Bayer, DB for Mobile Comp. 1
Database Support for Mobile Computing Applications
R. Bayer
Institut für Informatik
TU München
3.6.2000Rudolf/Vorlesungen/DWH-SS2000/DWH-MobileComp
3.6.2000 R. Bayer, DB for Mobile Comp. 2
Future Mobile Phones
• contain WEB browser
• have UTMS bandwidth 1.2 Mb/s
• integrated with GPS, i.e. exact position of phone and owner is known
entirely novel applications
3.6.2000 R. Bayer, DB for Mobile Comp. 3
Car Traveler on Road
• Car knows destination, gas consumption, gas remaining
• Questions and services:– reachable cheapest gas station along route?– next BMW repair station?– restaurant with in 100 km serving asparagus or
lobster?
3.6.2000 R. Bayer, DB for Mobile Comp. 4
Car Traffic Management in MunichAssumptions:
106 cars registered
105 cars traveling
Route-DB for preplanned routes, 10 per car, 104 B/route
106 cars * 10 routes/car * 104 B/route = 1011 B = 100 GB
Drive-DB
105 cars *1 route/car * 104 B/route = 109 B = 1 GB
3.6.2000 R. Bayer, DB for Mobile Comp. 5
Reads and UpdatesUpdates to Drive-DB: 1 update/(car*min)
105 cars*1 update/(car*min) =
105 updates/min ~ 1.700 t/s
Reads from Route-DB: travel time = 30 minutes
(105 cars/30 min)*1 read/car =
105 reads/(30*60) sec ~ 56 t/s
3.6.2000 R. Bayer, DB for Mobile Comp. 6
Route CalculationsInitial Routes: compute one optimal route on departure of car based on present traffic situation in Drive-DB
56 routes/s
Adaption of Routes: with every update of own position, car wants to know optimal route, in most cases the same as before?
1.700 checks/s
3.6.2000 R. Bayer, DB for Mobile Comp. 7
City Tourist• What is this? ( I am standing in front of?)
I want to know more, what is the URL?
• Where is the next bus or subway station, taxi point, public toilet, please guide me to it (load down part of city map with direct route inserted or text: )
• Where is medium priced fish restaurant within 500 m? Show it, make a reservation.
• I need an antihistamine, where is the next open pharmacy?
3.6.2000 R. Bayer, DB for Mobile Comp. 8
Air Traveler
• T is approaching airport Munich by car, server knows flight F and car or subway.
• „Proceed to parking P1, level 2, space 437“• „Mr. Bayer, you are checked into flight LH451 to
Cologne, leaving from gate A17, boarding time is 7:45, go towards gate in 7 minutes
• On return: parking ticket paid automatically, gate opens, when car approaches.
3.6.2000 R. Bayer, DB for Mobile Comp. 9
Truck Management
• What is position of trucks near Cologne with at least 1 ton loading capacity and slack of 1 hour in their delivery schedule?
• Show me planned travel route and stops of truck 327
3.6.2000 R. Bayer, DB for Mobile Comp. 10
Shoppers: Info pull or push?
• On entering Kaufhof, select WEB server
• Information pull:– guide me to the perfume dept.– bestsellers in detective stories?
• Information push (to close shoppers):– McDonald coming up 120 meters to right– H&M has bikini special– WOM: Madonna‘s new single just arrived
3.6.2000 R. Bayer, DB for Mobile Comp. 11
Nightlife
• Which friends are in Schwabing now?
• Who is DJ at P1?
• Live video shot with soundtrack from P1. ODODO, Kunstpark Ost
• „My position is ...“
• „Anybody close to share taxi to ...?
3.6.2000 R. Bayer, DB for Mobile Comp. 12
Sales Representative
• On approaching customer C: download the relevant marketing materials, sales and delivery data for C, combined with DWH.
• Show homepage and picture of person I meet• Did C have any reclamations recently?• Any significant changes in buying pattern of C
recently?• Question: B2B applications ???
3.6.2000 R. Bayer, DB for Mobile Comp. 13
Taxi Service
• Please pick me up to go to Kentvale apartments
• Taxi server finds optimal taxi: „Mr. Bayer, please stay where you are, a blue Comfort Taxi with plate SHA-488 368C will pick you up in approximately 3 minutes
3.6.2000 R. Bayer, DB for Mobile Comp. 14
Emergency Service
• Pushing the panic button calls police or ambulance
• mobile phone transmits position and medical data of owner, voice of attacker
3.6.2000 R. Bayer, DB for Mobile Comp. 15
Hotel Guest
• Theatre in walking distance showing movie with Meryl Streep starting around 20 h? Show map with route.
• reserve and pay ticket
• nearby bar serving Heineken?
• ...
3.6.2000 R. Bayer, DB for Mobile Comp. 16
The Database ProblemTypes of Subjects:
• Fixed location
• constant state: buildings, statues, paintings in museums, with a lot of additional information
• variable state: restaurants with seats
• Mobile• constant state, if subject refuses to disclose state • variable state
3.6.2000 R. Bayer, DB for Mobile Comp. 17
Attributes and Dimensions1. Location: 2 or 3 dimensions
2. Time: for tractable subjects like trucks
3. Classification of Subjects: hierarchies and MHC ~ subject ID, e.g.
automotive (cars, gas stations, parking, repair stations)eatingshopping arts 4 to 5 dimensions
4. State: movie playing now, number of free seats, ...probably modeled like features of GfK
3.6.2000 R. Bayer, DB for Mobile Comp. 18
Database Size (Mengengerüst)
1. Assumptions about Size
• 107 mobile subjects in Bavaria * 1000 B = 10 GB
• 105 fixed subjects, which are constant, but with 105
Bytes for image = 1010 B = 10 GB
• 105 variable subjects * 10 KB = 1 GB
11 GB with high update frequency !
3.6.2000 R. Bayer, DB for Mobile Comp. 19
2. Assumptions about Updates and Queries
A person is moving at most 10% of the time, i.e. 2.5 hours per day?
Update rate 1 per minute for variable subjects
11*105 variable subjects * 1 update per minute
= 11*105 /60 U/s ~ 20.000 updates /s
achievable with parallel DBMS !
3.6.2000 R. Bayer, DB for Mobile Comp. 20
Crosscheck for Airport Munich
20 flights /h* 300 passengers/flight =
6.000 passengers / h ~ DB size 60 MB
10 updates or queries per passenger?
60.000 t/h = 1000 t/m ~ 20 t/s
1 Server handles problem, second server for redundancy and mirroring DB!
3.6.2000 R. Bayer, DB for Mobile Comp. 21
Hurdles• Data Acquisition
– Mobile subjects: Telekom companies
– Fixed constant subjects: 105 * 10 DM = 1 million DM
– Variable subjects: free data via advertising
• Business Model– network providers
– content providers
– SW and technology providers