CM0256 Pervasive Computing Lecture 6 – Architecture Issues 1

Tom Goodalet.r.goodale@cs.cardiff.ac.uk

Lecture Outline

In this lecture we: Examine the issues surrounding Pervasive computing

architectures. What is an architecture ? What are the requirements ? ...

Basic Computer

Processor Memory I/O

Disks Display other

Generic Computer

Large main memory Fast processor

requires system manager to regulate temperature, voltage, etc

...

Generic Embedded computer

Small embedded computers may use a microcontroller as their main processing unit.

Software layers - single machine

Layers depend upon the system being considered.

Software Layers - environment

Machines need to talk to outside world Networking stack

Applications need to communicate and synchronise Distributed objects ? Databases ? Persistence ?

Change tracking ? Where does the data live and who owns it ?

Disconnected operation ?

Pervasive Computing

Embedded Networked Sensing Applications

Micro-sensors, on-board processing, wireless interfaces feasible at very small scale--can monitor phenomena “up close”

Enables spatially and temporally dense environmental monitoring

Contaminant Transport

Ecosystems, Biocomplexity

Marine Microorganisms Seismic Structure Response

Embedded Networked Sensing is revealing previously unobservable phenomena

Seismic Applications: Long-time users of sensor networks

Multi-Hopped Radio Linked Array features Time synchronization Network event detect Sequenced event transmission Deployments planned for UCLA

campus and the San Andreas Fault (100m-10 km)

Easily reconfigurable Worldwide application

Factor Building site 72 channels of 24-bit data 500 samples per second

continuous data recording Internet accessible real time data

monitoring Observation of 4 strong

earthquakes, including Alaska & Japan

Radio link

Fiberoptic link

The Ceiling Array: A Real Wireless Channel

Motes used to transmit and receive packets --A real-world augmentation to a virtual simulation

Scenario 1 (Weiser, 1991)

Sal awakens: she smells coffee. A few minutes ago her alarm clock, alerted by her restless rolling before waking, had quietly asked "coffee?", and she had mumbled "yes." "Yes" and "no" are the only words it knows.

Sal looks out her windows at her neighborhood. Sunlight and a fence are visible through one, but through others she sees electronic trails that have been kept for her of neighbors coming and going during the early morning. Privacy conventions and practical data rates prevent displaying video footage, but time markers and electronic tracks on the neighborhood map let Sal feel cozy in her street.

Scenario 1

Glancing at the windows to her kids' rooms she can see that they got up 15 and 20 minutes ago and are already in the kitchen. Noticing that she is up, they start making more noise.

At breakfast Sal reads the news. She still prefers the paper form, as do most people. She spots an interesting quote from a columnist in the business section. She wipes her pen over the newspaper's name, date, section, and page number and then circles the quote. The pen sends a message to the paper, which transmits the quote to her office.

Scenario 1

Electronic mail arrives from the company that made her garage door opener. She lost the instruction manual, and asked them for help. They have sent her a new manual, and also something unexpected -- a way to find the old one. According to the note, she can press a code into the opener and the missing manual will find itself. In the garage, she tracks a beeping noise to where the oil-stained manual had fallen behind some boxes. Sure enough, there is the tiny tab the manufacturer had affixed in the cover to try to avoid E-mail requests like her own.

On the way to work Sal glances in the foreview mirror to check the traffic. She spots a slowdown ahead, and also notices on a side street the telltale green in the foreview of a food shop, and a new one at that. She decides to take the next exit and get a cup of coffee while avoiding the jam.

Scenario 1

Once Sal arrives at work, the foreview helps her to quickly find a parking spot. As she walks into the building the machines in her office prepare to log her in, but don't complete the sequence until she actually enters her office. On her way, she stops by the offices of four or five colleagues to exchange greetings and news.

Sal glances out her windows: a grey day in silicon valley, 75 percent humidity and 40 percent chance of afternoon showers; meanwhile, it has been a quiet morning at the East Coast office. Usually the activity indicator shows at least one spontaneous urgent meeting by now. She chooses not to shift the window on the home office back three hours -- too much chance of being caught by surprise. But she knows others who do, usually people who never get a call from the East but just want to feel involved.

Active badge (ABng, 1998)

Active Badges (AT&T 2002)

Four generations of the Active Badge. •Bottom left, the first version, with a unique five bit code.•Bottom right, the second version, with a ten bit code.•Top left the third, current, version, with a forty-eight bit code, bi-directional capabilities, and an on-board 87C751 microprocessor.

Scenario 1

The telltale by the door that Sal programmed her first day on the job is blinking: fresh coffee. She heads for the coffee machine.

Coming back to her office, Sal picks up a tab and "waves" it to her friend Joe in the design group, with whom she is sharing a virtual office for a few weeks. They have a joint assignment on her latest project. Virtual office sharing can take many forms--in this case the two have given each other access to their location detectors and to each other's screen contents and location. Sal chooses to keep miniature versions of all Joe's tabs and pads in view and 3-dimensionally correct in a little suite of tabs in the back corner of her desk. She can't see what anything says, but she feels more in touch with his work when noticing the displays change out of the corner of her eye, and she can easily enlarge anything if necessary.

Weiser's Scratchpads

Scenario 1

A blank tab on Sal's desk beeps, and displays the word "Joe" on it. She picks it up and gestures with it towards her liveboard. Joe wants to discuss a document with her, and now it shows up on the wall as she hears Joe's voice:

"I've been wrestling with this third paragraph all morning and it still has the wrong tone. Would you mind reading it?"

"No problem."Sitting back and reading the paragraph, Sal wants to point to

a word. She gestures again with the "Joe" tab onto a nearby pad, and then uses the stylus to circle the word she wants:

"I think it's this term 'ubiquitous'. Its just not in common enough use, and makes the whole thing sound a little formal. Can we rephrase the sentence to get rid of it?"

Scenario 1

"I'll try that. Say, by the way Sal, did you ever hear from Mary Hausdorf?"

"No. Who's that?""You remember, she was at the meeting last week. She told

me she was going to get in touch with you."Sal doesn't remember Mary, but she does vaguely remember

the meeting. She quickly starts a search for meetings in the past two weeks with more than 6 people not previously in meetings with her, and finds the one. The attendees' names pop up, and she sees Mary. As is common in meetings, Mary made some biographical information about herself available to the other attendees, and Sal sees some common background. She'll just send Mary a note and see what's up. Sal is glad Mary did not make the biography available only during the time of the meeting, as many people do...

Scenario 2 (Banavar et al)

Albert uses his PDA as the main repository for his personal information management, or PIM, data. Yesterday morning, the batteries on his PDA died while he was walking over to Betty's office for a meeting. Of course, his PDA synchronizes with his laptop, but he did not have his laptop with him, just his mobile phone. So, he was stuck looking at the PIM data that he stores on his phone. This information is much less likely to be complete, since it is more tedious to enter data on his phone.

Scenario 2

When he got to Betty's office, he was a little early. The secretary gave him some new batteries for his PDA. He figured he would take the opportunity to print out his daily calendar. The offices are wired for a common printing service, so this should not have been a problem. He had printed his PIM data from his laptop many times, but the version of this application is different on his PDA. He spent an inordinate amount of time searching before he found the device's printing capabilities.

Scenario 2

During the meeting with Betty, Albert complained to her about his morning experience. She showed him a new PIM program that she uses, which looked better to him. He would have liked to start using it immediately, but he could not.

He got home that night, and used his laptop to upgrade his PIM program. He saw that this program uses a web-based location service to provide context awareness. He subscribes to a GPS service.

Scenario 2

Given his problems from earlier that day, Albert decided to synchronize all of his PIM information. It had been a while, since he always finds the synchronization process painfully complex. Sure enough, there was a number which he had updated in two different places, and he could not remember which was correct.

Scenario 3 (Raatikainen at al)

A younger physician has indicated interest in the result of a specific patient’s blood sample, because the patient’s condition has become worse overnight. When the lab result becomes available, a notification is sent to the computing device that happens to be nearest the physician — as he is walking in the corridor, this is the PDA in his pocket. He takes a look at the result and decides that he has to consult a senior physician and the nurse in charge of the patient at the ward. He sends a notification to them and asks them to meet him in the conference room.

Scenario 3

As he enters the conference room, the physician transfers the lab result graph to the SmartBoard in the room. He may control the graph viewed at the SmartBoard from his PDA. He discusses a new treatment with the senior clinician while the nurse studies the medicine description in the medicine book at a laptop in the room. Here she can see that discussed type of medicine is ill suited for the patient because of undesired effects. She explains the problem while displaying excerpts from the medicine book on the SmartBoard.

Scenario 3

They decide to give the patient another type of medicine right away and the younger physician records the changed prescription in the EPR. The nurse transfers the patient’s data onto her PDA, goes to the medication room and starts to find the medicine. While she is approaching the medicine room, the patient’s medication schema appears automatically on the PDA. When entering the medicine room the PDA discovers the barcode scanner located in the medicine cabinet containing the i.v. medicine. The nurse finds the medicine and uses the barcode scanner to register it. If there is a mismatch between the prescribed medication and the medicine scanned with the barcode scanner, a warning is shown on the PDA.

Scenario 3

The nurse goes to the patient in order to explain the new situation to him. At the bedside, she uses the patient’s TV in the ceiling to display the graph and other information from the patient record. The images shown on the TV are controlled from the nurse’s PDA. Finally, the PDA is used to mark the medicine as given to the patient and the time and initials are recorded.

Scenario 4 (Raatikainen et al)

After coming back from my office, I sit in the armchair in my living room to watch television. I point my PDA device at the television and the television control panel appears on it. I select the entry for today’s television programs, and the program is displayed on the television. I change channels by navigating the program on the TV display by moving a finger on my PDA screen. I select the program I’m interested in and the TV asks me if I want to watch the previous recorded version of that program first. I say ”yes”, and the recorded program starts playing.

After a while, I move to the table to get some coffee and a snack. Now, when I want to switch to a different program, the TV program is displayed on the table, and I can change the current TV channel by tapping on the program displayed on the table.

Scenario 4

At this point, my friend phones me. I pick up my video phone near the television. The control panel appears on the screen of the phone and it allows me to mute the sound of the television, and also to start recording the TV program so I can watch it later. While chatting with my friend, I can see his video on my television screen. During the phone conversation, I walk into the kitchen to refill my cup, and the video phone stream follows me there. The video is now displayed on the refrigerator screen (which is normally used to show recipes, calendars, and the like). After finishing the chat with my friend, I resume watching the TV program by navigating the control panel displayed on my PDA device.

Scenario 5 (Grimm et al)

Since resigning from her position at MIT and moving from Cambridge to the Bay Area, Alyssa has been highly successful as a speaker and consultant on the social impact of computing technology. Her clients include many local high-tech companies, professional organizations, as well as governmental institutions around the world. As part of her job, Alyssa visits different organizations around the Silicon Valley almost daily and frequently travels across the world.

Scenario 5

For managing her complex schedule and her numerous contacts as well as for communicating with clients she relies on a number of devices. At her office, Alyssa uses a conventional PC. In her opinion, keyboard, mouse, and a window-based interface still represent a very effective user interface, especially when writing reports and developing presentations. At home, her PlayStation 3 not only functions as a digital VCR and music jukebox, but also provides her with access to her contacts, schedule, and electronic mail.

Scenario 5

On the road, Alyssa prefers smaller, more portable devices. Her 4-band cell phone is the most important; in addition to global voice communications, it lets her access her personal information manager and provides her with a music player to entertain her during those long international flights. At a client’s location, she typically uses the client’s computing facilities to make presentations, and, when staying at a hotel, she uses the in-room information appliance to access her office workspace.

Scenario 5

But, for travel to less technologically developed parts of the world, she also relies on a pad with an optional keyboard. Across all these devices, Alyssa can access basically the same information and functionality. Her schedule and contacts are automatically synchronized between them. And, when accessing her workspace from a client’s computer or a hotel’s information appliance, she is presented with her desktop, featuring the same applications, data, and customizations as those on her office PC.

Scenario 5

Furthermore, many of the tasks centred around personal information management are performed automatically and often without human interaction.

For example, after agreeing on a meeting, the actual date and time for the meeting are automatically scheduled by her and her client’s personal information managers. And, her manager reacts to a successfully scheduled out-of-town meeting by making the necessary travel arrangements, booking appropriate flights and hotels, all based on Alyssa’s preferences, but without directly involving her (besides notifying her of the results).

Lecture Summary

In this lecture we have: Examined several scenarios and discussed their

requirements.

End of Lecture