Transcript Introduction

Introduction:
Pervasive and Mobile Computing
Defining Pervasive Computing
Make computing available beyond desktop
 Make it mobile and connected
 Instrument the person
 Instrument the physical surroundings
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Scenario 1 (at home)
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At Sue and Mike’s home, 10 minutes before their
alarm clock goes off (at 4:00 AM), the coffee
machine is automatically started.
In making breakfast, Mike realizes that the egg
supply is low. He adds eggs to the electronic
shopping list.
The refrigerator, scanning the barcode on the milk,
realizes that it will soon expire. Milk gets added to
the shopping list.
Before leaving for work, Sue sees that she has a
message reminding her that her driver’s license is
soon to expire. Sue uses her computer with the video
camera to get her picture taken and sent to the
nearest office.
Scenario 1 (at home)
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Mike is diabetic.
Mike uses a device that measures the glucose level
and transmits this information to his doctor’s office.
The doctor’s office keeps track of the measures and
if the doctor is concerned about a trend observed in
the measurements, the doctor’s office will send a
message for Mike’s home asking for an appointment.
If the problem is serious, then Mike’s dental
appointment may be cancelled since treating the
diabetes has high priority. If this happens, Mike’s
personal electronic agent negotiates with the dental
office-computing environment for an alternative time
which gets put into Mike’s schedule.
Scenario 1 (Mike at work)
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Mike works in an office tower for a company called
Big Internet Company (Bi Co) which occupies floors
11-21.
There is a separate elevator that accesses these
floors.
Mike places his hand on the scanner near the
elevator. The elevator has sensed Mike’s badge,
passed that information to a computer that took a
measurement of Mike’s hand, validated Mike and
ordered the elevator to the ground floor.
Scenario 1 (Mike at work)
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When Mike’s office senses that he is within 5 feet of
his office door, it unlocks.
The computer is already turned on, the printer
turned on and a list of the day’s meetings and
relevant background material is already printing.
Let’s say Mike finds that he has a conference call
with two colleagues in California and Toronto.
Mike verbally orders the conference call: “Connect
me with John Robinson and Tom Smith at 9”.
The room picks up this information and passes it to
the communication system to arrange for the call.
Scenario 1 (Mike at work)
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Mike’s badge beeps at 8:55 indicating that his
conference call is imminent. Mike returns to his
office.
Mike has his conference call at 9:01.
Just before 10 AM Mike heads to the Conference
Room A to meet with his lead developers. On the
way, Mike’s badge beeps and he sees that he has a
message from a developer, Tom who is away at a
conference.
Mike opens his PDA and selects PRINTERS. He
enters “Conference Room A” and three rooms near
Room A appear with brief descriptions of printers.
He selects one of the printers. The message from
Tom is printed.
Scenario 1 (Mike at work)
During Mike’s conference call, he writes on a
whiteboard.
 The contents of the whiteboard are
transmitted to the other conference call
participants and sent to Mike’s PC in his
office.
 The entire verbal dialog is recorded and
stored. It can be retrieved if one of the
conference call participants wishes to review
the meeting in further detail.
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Scenario 1 (Mike at work)
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After Mike’s meeting he spends the rest of the day
quietly in his office doing work and reading news.
Mike has the news delivered to him personalized. He
is especially interested in sports and local politics.
He started reading at home, but didn’t have time.
During the day (at work) he finishes reading the
news.
Mike is working on sensitive documents. When he
does leave the office (e.g., lunch) his terminal
automatically invokes a screen saver.
Sue’s personalized news consist of national politics
and technical stories.
Scenario 1 (Sue at work)
Sue is a doctor who starts rounds at 6AM.
 When Sue gets to the hospital, she has the
charts of patients downloaded to her PDA for
immediate perusal.
 During rounds she orders that a patient be
given a new medication.
 This gets sent to a computer in the hospital
which may find that the supply of this
medication is not enough. An order is
automatically made to a pharmacy.
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Scenario 1 (Sue at work)
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After rounds, Sue has a series of appointments and
lectures to attend. She is not able to get to her PC
for hours.
She has been tracking several favorite stocks
especially XYZ.
Since she is busy she initializes her personalized
financial advisor agent, Fred.
Sue tells Fred that she wants to know if the price of
XYZ reaches a certain point so that she may buy it.
At 11:17, Fred notifies her about XYZ.
Scenario 1 (Sue at work)
Sue asks Fred to check to see if she has
enough funds to cover for this.
 If the answer is yes, Fred buys the stock and
updates all of Sue’s accounts.
 Sue leaves at 5. Before she leaves, she finds
out that there has been a change in her
schedule and she doesn’t start rounds until
7:00AM.
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Scenario 1 (Back at Home)
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Sue cooks for relaxation.
She feels like making a special dish for which she
knows that she doesn’t have ingredients.
She goes to a grocery store. She doesn’t remember
all the ingredients so she asks her PDA to get the
recipe from home and the current shopping list.
Mike and Sue both arrive at home at 6:00PM. The
home-computing environment greets them on arrival
with a message for Mike telling him it is imperative
for him to check his messages.
Mike has the next day off and Sue gets to start a
little later. They instruct the home-computing
environment to set the alarm an hour later.
Scenario 2
Middlesex Building Pervasive Computing
Environment
 The application scenarios focus on users
requesting building-related that can be
accessed by their PDA, laptop or PC.
 We will refer to this as Building Information
Management (BIM).
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Scenario 2
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BIM Services for Resource Location
o A user in a building is able to query for the
location of rooms or nearest available resource
(e.g., nearest available workstation, printer). Maps
and directions are provided to the user upon
request.
o For example, Bob can request the location of the
nearest printer (in Middlesex) that he is allowed
access to. If needed, Bob could request a map or
specific directions. Different maps and directions
are returned based on Bob's location.
o Different users will have different requests
Scenario 2
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BIM Services for Activity Information
o A user can request information about activities in
the building (e.g., class , exam, meeting). Such a
query should return a list of activities with room
numbers.
o For example, upon entering Middlesex, Bob
requests information on activities. Seeing the
category for `final exam schedule', Bob asks for
final exams taking place in the building at that
time.
Scenario 2
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BIM Services for Status Information
o A user is able to request information about the
status of a person within a building.
o For example, Bob can request information about
Sue. The BIM should be able to tell Bob if Sue is
busy or not. Sue is inferred to be busy if her
location is in a meeting room or if she is working at
a computer;
Scenario 2
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Other BIM Services
o A meeting causes the the room to become
warm.
o Temperature should be adjusted.
What do we need to support
this?
Lots of things.
 We need a very complex and distributed
infrastructure that has the following
properties:
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Invisible from the user’s point of view.
Adaptive
Very dependable
All devices are network enabled, although not all
devices are connected all the time.
o Everywhere
Issues in Network
Communications
Mix of wireless and wired
 A heterogeneous set of technologies will most
likely be needed
 Mobility brings its own sets of problems.
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Issues in Network
Communications (Mobility)
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Link Effects
o Bandwidth is lower than the bandwidth provided
by the wired network.
o The link between the base station and mobile host
is not a reliable as links in a wired network (limits
bandwidth)
o Need to be able to adapt content based on device
and available bandwidth.
Issues in Network
Communications (Mobility)
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Link Effects (Continued)
o Remember Mike’s and Sue’s personalized news.
The presentation of that news may vary depending
not only on the type of device they are using to
read the news, but also on the available bandwidth
between the PDA and a base station.
o Let’s say Mike is driving while Sue is reading the
news off her PDA. As Mike moves, the available
bandwidth will change. How should the
presentation change?
Issues in Network
Communications (Mobility)
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Constraints imposed by portable devices
o User interface: little “real estate”
o Power management has an impact on the available
computing resources available for the mobile
device.
o Currently, it is not always desirable to have mobile
devices always connected. This saves power, but
results in problems related in intermittent
connections (discussed in more detail later).
Issues in Network
Communications (Mobility)
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Dynamic information
o The request for information sometimes depends
on the location
—Example: Where is the nearest gas station?
—Example: Where is the nearest Italian restaurant where
the average meal is less than 30 dollars Canadian.
o The presentation of the information relies on the
available computing resources.
—Example: Text is used if available bandwidth is below
some specified threshold else images may be used.
Issues in Network
Communications (Mobility)
How will a user be found so that important
information can be delivered to them?
 For example, let’s say that Mike’s glucose
levels are very high, the doctor needs to see
him right away and Mike is traveling between
sites that day.
 How is Mike to be found?
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o Do tagging technologies work?
o What about the PDA? What if Mike doesn’t
check it?
Issues in Network
Communication (Connectivity)
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Intermittent Connectivity
o Ideally, there are invisible, trouble-free
connections and disconnections.
o However, we need intermittent connectivity so
that we can disconnect to consume less power.
o Lots of new mobile protocols are appearing (e.g.,
Bluetooth and HomeRF) are standards that allow
devices to connect and disconnect as needed.
o Does not address complex issues such as handoffs.
Issues in Identification and
Location
There is a need to identify physical noncomputing entities e.g. people, an item in an
exhibit display
 There are several possible technologies
including tags, computer vision and
positioning.
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Issues in Identification and
Location
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Tag technology includes:
o Infrared
—Can attach to a person (as a badge) or to a thing (e.g. a
printer).
—Emit an identifier using IR technology.
—Relatively short distance
o Optically sensed
—Includes standard barcodes
—Readers are needed such that the tag is placed right
next to the reader.
Issues in Identification and
Location
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Tag technology includes:
o RFID
—Use radio frequency (RF)
—Can be read from a distance
—Do not require their own power source
o Contact tags
—Do not require their own power source.
Issues in Identification and
Location
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Tagging technology
o There is not one correct tagging technology to
use.
o The best choice depends on cost and suitability of
the physical environment
o Exact location may be difficult to determine.
—Example: IR receivers are really only detecting that an
IR transmitter has sent an identifier. You may need
several IR receivers reporting that they have seen an IR
identifier to pinpoint location.
Issues in Identification and
Location
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Computer Vision
o Computer vision techniques can be used for object
recognition
o Example: Room uses footsteps to identify a
person
o Requires a good deal of computing resources
o A lot of work is needed to make this a viable
technology
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Positioning
o Can be used where objects move rarely
o Example: GPS
Data Transfer
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Need to be able to transfer data in a seamless
fashion.
Data initiation and termination takes place using a
variety of devices.
o Sue sending a picture of herself to get her license renewed.
o Mike downloading a document (through his PDA) sent by
Tom. Tom could have sent the document using his PDA or a
PC and Mike could have downloaded the document through
his PC.
o Making sure that the “personalized newspaper” getting to
the device that the user is reading from. User should not
have to worry about things like different formats or ftp.
The presentation of the content should adapt to the device
that the user is using.
Data Transfer
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Data is heterogeneous in nature
o Video, Image, Text, WORD Document, Audio,etc
o Services are needed to take content and
transform to appropriate presentation.
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Network topologies of devices (eg., PDAs,
sensors, printers, coffee makers) are
becoming increasingly more dynamic and thus
increasingly are networks are becoming more
ad-hoc.
Data Transfer
The progression of data through the network
needs to be seamless i.e., the users should
not have to know which devices the data is
being transferred over or the formats
needed to the end user to read it.
 The “computing system” must also manage a
ubiquitous persistent storage.
 Replicated data should be consistent.
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Resource Discovery
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In the scenario, Mike asked for a list of printers
that were available to him.
The set of printers in a building constantly change
i.e., it is not static.
When a printer is “plugged” in how does the printer
tell the building that it is available.
There are issues with lookup services and
connectivity.
o A PDA may store the list of printers so that if the lookup
service is down, the user still has a list of printers.
o When the list of printers changes, when should the PDA be
informed?
Resource Discovery
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The home environment will have “appliances”
that are part of the home computing
environment. This includes alarm clock,
coffee make, refrigerator, etc; When an
appliance is bought and plugged in, it must be
made known to the computing environment.
Agent Technology
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The scenario described the use of agents -- one for
scheduling and one that bought stocks.
An agent can be defined as a “component of software
and/or hardware which is capable of acting
exactingly in order to accomplish tasks on behalf of
its user.”
Agent technology and protocols for mobile computing
is not well understood. This will draw upon knowledge
from AI, networking and distributed systems, and
databases.
Trigger Management
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An event could cause a number of actions.
Examples:
o Alarm clock and coffee maker
o Entering an office and having the temperature set and the
PC turned on.
o A high glucose level causing an appointment to be made.
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Issues
o What if there are conflicts?
o Seamless integration
o Dynamically changing
Trigger Management
Example: Sue and Mike’s scheduled changed
so that there is a new time to ring the alarm,
start the coffee maker.
 Example: What if Sue and Mike decided to
only drink coffee on the weekend or eliminate
it alltogether.
 Example: How does Mike’s home computing
system know that it is ok to have the doctor’s
office override all appointments. What if
Mike wants to hide something from Sue?
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Sensors
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If we are to adjust temperature based on
the number of people and the current
temperature then:
o Sensors measuring temperature are needed
o Determining the number of people in a room is
needed
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Sensors are “lightweight” devices;
o Current network protocols e.g., TCP may not
work well.
o What about power?
User Interface Devices
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Currently, the primary devices we use to interact
with the “computing system” are a keyboard and a
mouse.
Voice recognition systems are becoming more
sophisticated, but I can’t tell the room “make me
coffee” or “set up a conference call”. At least not
yet.
What about “pen” input?
o In a conference, a person may write something on a
whiteboard.
o If the participants are in remote locations, it would be nice
if that information on the whiteboard appeared at each
participant’s preferred device.
o This would certainly be easier than having someone record
everything, type it up and then send it.
Ease of Use
People can’t program their VCR and yet they
are to program event management in their
homes or offices.
 We don’t want to know about data formats,
battery power.
 We care about a seamless and inexpensive
environment.
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Privacy and Security
Take the temperature adjustment
 An “enemy” organization could seize control
and adjust the temperature so that it is
difficult for people work and thus making it
less secure.
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Software Development
How can software development be
faciliated?
 Testing
 Maintenance
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