January 25, 2007January 25, 2007 11

ECET 581/CPET/ECET 499ECET 581/CPET/ECET 499 Mobile Computing Technologies & AppsMobile Computing Technologies & Apps

Data Dissemination and Management Data Dissemination and Management 1 of 21 of 2

Lecture 6Lecture 6

Paul I-Hai Lin, Professor Paul I-Hai Lin, Professor Electrical and Computer Engineering TechnologyElectrical and Computer Engineering Technology

Indiana University-Purdue University Fort WayneIndiana University-Purdue University Fort Wayne

January 25, 2007January 25, 2007 22

Data Dissemination and Management - Data Dissemination and Management - TopicsTopics

IntroductionIntroduction ChallengesChallenges Data DisseminationData Dissemination Mobile Data CachingMobile Data Caching Mobile Cache Maintenance SchemesMobile Cache Maintenance Schemes Mobile Web CachingMobile Web Caching SummarySummary

January 25, 2007January 25, 2007 33

Data Dissemination and Management – Data Dissemination and Management – Topics Topics (cont.)(cont.)

IntroductionIntroduction• Pull (On-Demand) ModePull (On-Demand) Mode• Push (Publish-Subscribe) ModePush (Publish-Subscribe) Mode• Information CachingInformation Caching

ChallengesChallenges• Architecture-basedArchitecture-based• Architecture-lessArchitecture-less

Data DisseminationData Dissemination• Bandwidth Allocation for PublishingBandwidth Allocation for Publishing• Broadcast Disk SchedulingBroadcast Disk Scheduling

January 25, 2007January 25, 2007 44

Data Dissemination and Management – Data Dissemination and Management – Topics Topics (cont.)(cont.)

Mobile Data CachingMobile Data Caching• Caching in Traditional Distributed SystemsCaching in Traditional Distributed Systems• Cache Consistency MaintenanceCache Consistency Maintenance• Performance and Architecture IssuesPerformance and Architecture Issues

Mobile Cache Maintenance SchemesMobile Cache Maintenance Schemes• A Taxonomy of Cache MaintenanceA Taxonomy of Cache Maintenance• Cache Maintenance for Push-based Information DisseminationCache Maintenance for Push-based Information Dissemination• Broadcasting Invalidation ReportsBroadcasting Invalidation Reports• Disconnected OperationDisconnected Operation• Asynchronous Stateful (AS) Scheme Asynchronous Stateful (AS) Scheme • To Cache or Not to CacheTo Cache or Not to Cache

Mobile Web CachingMobile Web Caching• Handling DisconnectionsHandling Disconnections• Achieving Energy and Bandwidth Achieving Energy and Bandwidth

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Data Dissemination and Management - Data Dissemination and Management - IntroductionIntroduction

Mobile Information Content and Mobile Information Content and ApplicationsApplications• Email, Messaging, NewsEmail, Messaging, News• Public Transportation, Traffic, Flight StatusPublic Transportation, Traffic, Flight Status• Business Info, Financial Info, Banking, Stock Business Info, Financial Info, Banking, Stock

quotes, Salesquotes, Sales• Events, ParkingEvents, Parking• Tourism, Hotel, Restaurants, WeatherTourism, Hotel, Restaurants, Weather• MedicalMedical• Consumer Services, Yellow pagesConsumer Services, Yellow pages

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Data Dissemination and Management – Data Dissemination and Management – Introduction Introduction (cont.)(cont.)

Mobile Information ServersMobile Information Servers• EmailEmail• Web PortalWeb Portal• Calendar, Tasks, and ContactsCalendar, Tasks, and Contacts• etcetc

Possible CombinationsPossible Combinations• HardwareHardware• Network Protocols (Wireless Access Protocols, Network Protocols (Wireless Access Protocols,

GSM/Circuit, TDMA/CDPD, TDMA/Circuit)GSM/Circuit, TDMA/CDPD, TDMA/Circuit)• BrowsersBrowsers• GatewaysGateways

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Data Dissemination and ManagementData Dissemination and Management Mobile Application ConsumersMobile Application Consumers

• Wireless Sync and Go connectivity & Mobile Wireless Sync and Go connectivity & Mobile web servicesweb services

• PIM: contacts, calendar, tasks, email, and PIM: contacts, calendar, tasks, email, and notesnotes

• Desktop cradle synchronizationDesktop cradle synchronization

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Data Dissemination and Management - Data Dissemination and Management - Introduction Introduction (cont.)(cont.)

Mobile Application Server Architecture Mobile Application Server Architecture (Data & Information) (Data & Information) • 11stst Tier – Thin clients Tier – Thin clients• 22ndnd Tier – Communications & Business Tier – Communications & Business

ApplicationsApplications• 33rdrd Tier – Applications Systems (ERP, CRM, Tier – Applications Systems (ERP, CRM,

etc)etc)

January 25, 2007January 25, 2007 99

Data Dissemination and Management - Data Dissemination and Management - Introduction Introduction (cont.)(cont.)

Wireless Communication ProblemsWireless Communication Problems• Physical MediumPhysical Medium

Signal FadingSignal Fading Path LossPath Loss InterferenceInterference Time dispersionTime dispersion

• Lower bandwidthLower bandwidth• Higher error ratesHigher error rates• Higher communication latencyHigher communication latency

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Data Dissemination and Management – Data Dissemination and Management – Introduction Introduction (cont.)(cont.)

Mobile Communication InfrastructuresMobile Communication Infrastructures• Wi-FiWi-Fi• Wi-MaxWi-Max• CDMA (Code Division Multiple Access)CDMA (Code Division Multiple Access)• GPRS (General Packet Radio Service; for data GPRS (General Packet Radio Service; for data

packet service on GSM network) packet service on GSM network) • EDGE (Enhanced Data GSM Evolution, up to 384 EDGE (Enhanced Data GSM Evolution, up to 384

Kbps)Kbps)• 3G (33G (3rdrd Generation Wireless Technology include Generation Wireless Technology include

enhanced multimedia, and upwards of 2 Mbps enhanced multimedia, and upwards of 2 Mbps throughput)throughput)

• Bluetooth, IrDA, IrFM, OMA (Open Mobile Alliance) Bluetooth, IrDA, IrFM, OMA (Open Mobile Alliance) Device ManagementDevice Management

January 25, 2007January 25, 2007 1111

Data Dissemination and Management - Data Dissemination and Management - Introduction Introduction (cont.)(cont.)

Mobile Application Servers (Data & Information) Mobile Application Servers (Data & Information) • Enterprise Resource Planning (ERP)Enterprise Resource Planning (ERP)• Customer Resource Management (CRM)Customer Resource Management (CRM)• Sales Force AutomationSales Force Automation• Financial Accounting SystemFinancial Accounting System• Manufacturing SystemsManufacturing Systems• Field ServicesField Services

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Data Dissemination and Management –Data Dissemination and Management –Introduction Introduction (cont.)(cont.)

Examples of Mobile Application ServersExamples of Mobile Application Servers• IBM & Aligo Mobile Application ServerIBM & Aligo Mobile Application Server• Oracle Mobile Application ServerOracle Mobile Application Server• Sybase Mobile Application ServerSybase Mobile Application Server• Microsoft Mobile Application ServerMicrosoft Mobile Application Server• Mobile Web Application Architecture, Mobile Web Application Architecture,

http://www.asp.net/mobile/2514A_01A001.swfhttp://www.asp.net/mobile/2514A_01A001.swf

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Data Dissemination and Management – Data Dissemination and Management – Introduction Introduction (cont.)(cont.)

Other Related Tasks and/or ModulesOther Related Tasks and/or Modules• Mobile Data/Information IntegrationMobile Data/Information Integration• Global Mobile Information SystemGlobal Mobile Information System• Mobile Information Protection & SecurityMobile Information Protection & Security• Mobile Information CenterMobile Information Center• Unified Data ModelUnified Data Model• Middleware for Mobile Information AccessMiddleware for Mobile Information Access

January 25, 2007January 25, 2007 1414

Data Dissemination and Management – Data Dissemination and Management – IntroductionIntroduction (cont.)(cont.)

Mobile Information Delivery MethodsMobile Information Delivery Methods• Push (Publish-Subscribe) ModePush (Publish-Subscribe) Mode

Information broadcasting when its availableInformation broadcasting when its available Resource-efficientResource-efficient ScalableScalable

• Pull (On-Demand) ModePull (On-Demand) Mode User send query for particular information to an User send query for particular information to an

information source (server or peer)information source (server or peer) ReplyReply

• Information CachingInformation Caching Document, filesDocument, files

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Data Dissemination and Management – Data Dissemination and Management – IntroductionIntroduction (cont.)(cont.)

Issues of Mobile Information ServicesIssues of Mobile Information Services• Publication Content: Which itemsPublication Content: Which items• Publication Frequency: How oftenPublication Frequency: How often• Bandwidth Allocation:Bandwidth Allocation:

Uplink channelsUplink channels Downlink channelsDownlink channels

• How can mobile users access services How can mobile users access services transparently?transparently?

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Data Dissemination and Management – Data Dissemination and Management – IntroductionIntroduction (cont.)(cont.)

How can mobile users access services transparently?How can mobile users access services transparently?

Data Server

Figure 3.1 Broadcast channel

Base-station(cell d)Base-station

(cell c)

Inde

x | S

tock

| Tr

affic

| S

ales

Mobile m’s trajectory

Data ServerIn

dex

| Eve

nts

| Par

king

| S

ales

Adapted from the Text: Fundamentals of Mobile and Pervasive Computing, 2005, by Frank Adelstein, et. al, McGraw-Hill

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Data Dissemination and Management – Data Dissemination and Management – IntroductionIntroduction (cont.)(cont.)

• How can their energy consumption be How can their energy consumption be minimized? (Energy efficient Info services) minimized? (Energy efficient Info services)

Low-power radio circuit – matching a predefined Low-power radio circuit – matching a predefined set of packet addressset of packet address

Store data in a low-energy bufferStore data in a low-energy buffer Wake-up the CPU after a certain time intervalWake-up the CPU after a certain time interval Run CPU clock in a low-power modeRun CPU clock in a low-power mode