p03 issues

7/28/2019 P03 Issues

1/34

ISA5428: Research Issues

7/28/2019 P03 Issues

2/34

7/28/2019 P03 Issues

3/34

Pervasive Computing Research Issues-2

Outline

Related fields Distributed System

Mobile Computing

Pervasive Computing Example scenario

Drill down

Conclusion

7/28/2019 P03 Issues

4/34


Distributed Systems

Research involving two or more computersconnected by a network

Areas foundational to pervasive computing:

Remote communication: protocol layering, RPC,end-to-end argument

Fault tolerance: atomic transactions, two phasecommit

High availability: replica control, mirrored execution,recovery

Remote information access: caching, functionshipping, distributed file system

Security: authentication, privacy

7/28/2019 P03 Issues

5/34


Mobile Computing (1/2)

Research on building distributed systems withmobile clients

Principles in distributed system design still apply

4 constraints to distinguish it from distributedsystems and demand new research Unpredictable variation in network quality

Lowered trust and robustness of mobile elements

Limited local resources imposed by weight and size Battery power consumption

7/28/2019 P03 Issues

6/34


Mobile Computing (2/2)

Research areas: Mobile networking: mobile IP, ad hoc protocols,

improving TCP performance in wireless networks

Mobile information access: selective control ofdata consistency

Support for adaptive applications: transcoding byproxies

System-level energy saving techniques: energy-

aware adaptation, variable speed processorscheduling

Location sensitivity: location sensing, location-aware system behavior

7/28/2019 P03 Issues

7/34


Pervasive Computing

Pervasive computing environment:An environment saturated with computing and

communication capability, yet so gracefully integratedwith users that it becomes a technology thatdisappears

Subsume distributed computing and mobilecomputing, but incorporate 4 additional researchthrusts (next figure)

7/28/2019 P03 Issues

8/34


7/28/2019 P03 Issues

9/34


4 Additional Research Areas (1/2)

Effective use of smart spaces: Space: an enclosed area or a well-defined open area

Smart space: embedding computing infrastructure inbuilding infrastructure => physical/virtual converge

Enable sensing and control of one world by the other

Example?

Invisibility:

Minimal user distraction is a more practical goal Ex.: the environment continuously meets user

expectations and rarely presents him with surprises

Some alerts may still be needed

7/28/2019 P03 Issues

10/34


4 Additional Research Areas (2/2)

Localized scalability: Increasing complexity in interactions between a users

personal computing space and surroundings as wellas other persons

Must consider scalability with physical distance

Masking uneven conditioning Different environments will have huge differences in

their smartness, causing user distraction

One solution: have users personal computing space tocompensate

Complete invisibility may be impossible, but reducedvariability is possible

7/28/2019 P03 Issues

11/34


Outline

Related fields

Example scenario Scenario 1

Scenario 2 Miss Capabilities

Drill down

Conclusion

7/28/2019 P03 Issues

12/34


Scenario 1

Jane is at Gate 23 of an airport and would like toe-mail her edited files through wirelessconnection, but the bandwidth is miserable

Aura, the pervasive computing environment,detects the situation, consults airport servers,and finds Gate 15 will have no flight in 1.5 hour

Aura suggests Jane to go to Gate 15 and

prioritize her email Jane accepts the suggestions

Files are transmitted at Gate 15 and Aurainforms Jane when she needs to be back to gate

7/28/2019 P03 Issues

13/34


Scenario 2

Fred has to walk to a meeting from his office togive a presentation, but he is not quite ready yet

Fred grabs a handheld computer and starts

walking to the meetingAura transfers his state from desktop to

handheld, and Fred does final editing with voice

Aura infers Freds schedule, downloads materials

to projection computer and warms up projector Rooms face detection system recognizes some

unfamiliar faces and advises Fred not to showsensitive data

7/28/2019 P03 Issues

14/34


Some Key Aspects

Scenario 1: Proactivity: Aura can estimate how long the whole

process takes and look ahead on her behalf

Combining knowledge from different layers: wirelesscongestion and boarding time

Smart space: provide information of wireless BW,flight time and gates, distance between gates

Scenario 2: Moving execution state across diverse platforms

Automatic adjusting behavior to fit circumstances:voice inputs

Proactivity and smart space

7/28/2019 P03 Issues

15/34


Missing Capabilities

Component technologies are simple and basic They are available today

The challenge:

The seamless integration of componenttechnologies into a pervasive computing systemArchitecture

Component synthesis

System-level engineering

7/28/2019 P03 Issues

16/34


Outline

Related fields

Example scenario

Drill down

User intent Cyber foraging Adaptation strategy High-level energy management Client thickness

Context awareness Balancing proactivity and transparency Privacy and trust Impact on layering

Conclusion

7/28/2019 P03 Issues

17/34


The Model

Each user is immersed in a personal computingspacethat mediates all interactions with thepervasive computing elements in surroundings

As a command center System design: wearable computer? personal

assistant? thicker or thinner? what sensors andnetworking?

Context aware: how to know users state andsurrounding, and modify behavior

How to cooperate and interact with infrastructure?with other persons?

How to roam and adapt? reconfigurable? => PDA with 802.11b, Java

7/28/2019 P03 Issues

18/34


Issue: Smart Object/Environment

Provide services System design: which embedded system? web server?

sensors and actuators? NW?

Naming, registration, discovery

Physical/virtual mapping

Mobile management, energy management

Service composition, I/O matching, adaptation,environment monitoring

7/28/2019 P03 Issues

19/34


Issue: Infrastructure Support

Infrastructures in real life e.g., electricity, roads, ...

Just there or even invisible, open platform

Internet infrastructure Domain name service (DNS registry)

Services: cooperating routers, time servers

TCP/IP: common formats/protocols

Web standards Extend the Internet to everyday objects

7/28/2019 P03 Issues

20/34


Infrastructure for Smart Objects

Guarantee Security, privacy, availability, reliability

Provide services

Location (Where am I?) Context (Are we in a meeting?)

Event delivery (Tell me when... happens)

Brokering (Find something that)

Directory, discovery, registry Mobility, roaming,

...

How do we organize billions ofmobile smart objects that arehighly dynamic, short living,?

For applicationsbuilt with smart

objects

For smartobjects

7/28/2019 P03 Issues

21/34


Issue: User Intent (1/2)

A pervasive computing system must track userintent Determine which actions will help, not hinder, user

Ex.: suppose a user is viewing video over a network,whose bandwidth suddenly drops. Should the system

Reduce the fidelity of the video?

Pause briefly to find another higher-bandwidthconnection?

Advise the user that the task can no longer beaccomplished?

Correct choice depends on what user is trying toaccomplish

7/28/2019 P03 Issues

22/34


User Intent (2/2)

Todays applications either have no idea aboutuser intent (e.g. to support adaptation andproactivity), or do it badly

Issues: Can user intent be inferred, or does it have to be

explicitly provided?

How is user intent represented internally? What arerepresented?

How does one characterize accuracy of knowledge? Isincomplete or imprecise information useful?

Will obtaining intent place an burden on the user?

7/28/2019 P03 Issues

23/34


Issue: Cyber Foraging (1/2)

Dynamically augment computing resources ofend user devices with wired hardwareinfrastructure => surrogate

Usage: On entering a neighborhood, a device detects the

presence of surrogates and negotiates its use

Surrogates serve as gateway to the Internet andserver for heavy computation

When the device leaves the neighborhood, surrogatebinding is broken and staged data are discarded

7/28/2019 P03 Issues

24/34


Cyber Foraging (2/2)

Issues: How to discover the presence of surrogates?

How to establish an appropriate level of trust? How toamortize the cost of establishing trust?

How to balance the load of surrogates?

How to minimize latency in serving devices?

How to deploy surrogates? How scalable?

How to make surrogate uses seamless and minimallyintrusive for a user?

7/28/2019 P03 Issues

25/34


Issue: Adaptation Strategy (1/2)

Necessary when there is significant mismatchbetween the supply and demand of a resource,e.g. bandwidth, energy, computing cycles, ...

Three strategies for adaptation The client guides applications in changing their

behavior

The client asks the environment to guarantee acertain level of a resource

The client suggests a corrective action to the user

7/28/2019 P03 Issues

26/34


Adaptation Strategy (2/2)

Issues: How does a client choose between adaptation

strategies? How strategies be changed seamlessly asuser moves?

How to do resource reservation in a smart space?What are appropriate admission control policies?What API are needed to make reservation?

Will corrective actions be intrusive? How to do it, e.g.

API, programming model? What is the relationship between lowing fidelity and

adaptation?

7/28/2019 P03 Issues

27/34


Issue: High-Level Energy Management

Necessary because low-level techniques, e.g.battery and circuit design, are insufficient

Issues:

What high-level systems can be managed for energyefficiency? (memory, application adaptation, )

Are they intrusive to the user? Can user intent help?

Can smart spaces and surrogates be used to reduceenergy demand on a mobile device?

How to tradeoff the energy used in remote executionwith wireless connection?

7/28/2019 P03 Issues

28/34


Issue: Client Thickness

How powerful does a mobile client need to be? From bare-bones devices (high-resolution displays thru wireless

to servers) to full-function clients (standalone & disconnectedoperation)

Issues: How to quantify thickness with env. conditioning, e.g., sensors

added and better networking?

How to migrate app. between clients of different thickness?

How to cooperate with infrastructure?

Can clients be reconfigurable to adapt to env.? Semi-portable infrastructure for less hospitable env.?

How to roam transparently? especially from a benignenvironment to a poor one?

How to lower the cost of diversity in devices?

7/28/2019 P03 Issues

29/34


Issue: Context Awareness

Needed for an environment minimally intrusive Recognize user state and surroundings

Make decisions proactively, modify behavioraccordingly

Issues: Obtaining information needed to function

How to represent context internally? How to combineit with system and application state? Where to store?

How often to update and consult context information?

What services does the infrastructure have to provide?

How to track location? sense surroundings?

7/28/2019 P03 Issues

30/34


Issue: Proactivity and Transparency

How not to annoy a user in a proactive system?=> self-tuning according to user expertise andexperiences

Issues: How are user preferences and tolerances specified

and taken into account?

How to determine the right level of balance?

7/28/2019 P03 Issues

31/34


Issue: Privacy and Trust

A pervasive computing environment needs tomonitor user actions almost continuously inorder to be effective

Need mutual trust between environment anduser

Issues: Tradeoff between seamless system behavior and

privacy/trust enforcementAny appropriate authentication techniques?

How to specify security constraints? How to specifyones identity?

7/28/2019 P03 Issues

32/34


Issue: Impact on Layering

Pervasive computing often requires merginginformation from different layers a system

Issues:

Relationship between layering and pervasivecomputing

How to create a new layer?

7/28/2019 P03 Issues

33/34


Conclusions

Almost all sub domains in CS are affected System infrastructures, networking, security, user

interfaces, embedded systems, AI, perception, speechrecognition,...

We are already moving in this direction XML, UDDI, mobile IP, Jini, ...

Systems integration is the key

Many new and fascinating research problemsemerge!

7/28/2019 P03 Issues

34/34


The Field Is Burgeoning

IEEE Pervasivemagazine

Springer Personal and Ubiquitous Computing

Ubicomp

Various links to universities, research institutes,companies

p03 issues

Documents