6.033: Computer Systems Engineering, Spring 2003 | Handout 23, April 17, 2003 |
In this project, you'll design an application that makes use of a new technology called 'radio frequency tagging'. We describe below a particular application (tracking students within MIT), but you are free to choose your own application instead. If you do so, you will be expected to hand in an additional one-pager describing its goals and key design issues.
Check out DP2 FAQ, for the most up-to-date clarifications.
A radio frequency identity (RFID) tag is a device that can be used to identify an object to which it is attached. The tag consists of an integrated circuit and an antenna, and is small enough to be sewn into a clothing label. When interrogated by a reading device, the tag discloses an identifier stored internally. No battery is necessary; the tag can be energized by waves received by the antenna. A tag stores 64 or 96 bits of data. A variant allows the tag to be written as well as read, but this adds enough to the cost to rule out use for the most compelling applications, in which tags are attached to inexpensive objects. A read-only tag currently costs about 5-10 cents, but the price is expected to drop sufficiently that, for most applications, the tags themselves will be considered free.
RFID readers, in contrast, are heavy and moderately expensive; they currently cost about $100, although the price will no doubt drop over time. The reading range depends on the frequency used, and whether the tag is equipped with its own battery. For your project, you should assume simple passive tags, which have a range of less than 10m.
A group at MIT has been at the forefront of RFID research, and has established a center for promulgating the technology and developing standards. The center's website is a good starting point for information about the technology and its potential uses. As you develop your design, you'll need to investigate any relevant properties that might help or hinder it. For example, you may need to consider interference between readers, or the likelihood of errors.
Most of the suggested applications for RFID tags involve the tracking of merchandise. Walmart and the British supermarket chain Tesco have started to install 'smart shelves' that can track items as they are placed or removed. In the Prada store in Manhattan, garments carry tags identifying style, size, color, etc. Benetton plans to use tagging to track the contents of packages during distribution. Tagging is being touted as a means of reducing theft. Gillette, for example, has ordered half a billion tags to track razors; libraries and bookstores have started to tag books; and it has been suggested that a smart shelf might signal an alarm if an unexpectedly large number of items are removed quickly.
Many other applications have been proposed, from locating buried objects, such as pipelines, to monitoring patients.
Some of the most powerful applications are likely to be those that correlate items with their human users, by having the users wear or carry tags. For example, tags might replace keys: your car might open for you automatically, and adjust the seat to your preferred position. The privacy implications of such applications are a great concern. More worryingly, the FDA recently approved the 'Verichip', a tag encapsulated in glass that can be injected under the skin with a hypodermic. Some proposed applications of such tags (conveying medical records or locating lost or kidnapped children) seem benign, but others are more sinister. In a recent interview, Richard Sullivan, CEO of Applied Digital Solutions suggested that foreigners visiting the US have tags forcibly implanted. Concern over potential infringement of civil liberties has been raised over more mundane uses of tagging. In response to recent protests, Benetton has dropped its plans to tag its clothes.
Here are some ideas for applications, should you decide to pick one of your own:
If you choose to do the StudentTracker:
If you choose an application of your own:
StudentTracker is a system that provides students with information on the whereabouts of other students. It provides an interface that allows students to ask for the location of another student, and to specify which students may track them.
Two kinds of location are reported. Sometimes, the system will simply report that a student was last detected near a particular landmark: "1.10pm: waldo at food trucks". Often, though, it will be possible to report that a student is currently within a room or building: "11.35am: waldo in 34-101 since 11.05am". In this case, the location report will give the relevant room, and the time at which the student entered, in addition to the timestamp.
Location reports are delivered in two ways. In query mode, which is synchronous, a student asks for the location of another student, and awaits a response, which should be received in a few seconds. In callback mode, which is asynchronous, a student registers a request to be informed when another student arrives in a particular location; if and when that student appears in the specified location, the requester is notified. The system also offers historical reporting, which provides the locations of a particular student in the past, and the students at particular locations at given times.
The interface provides, in addition to the location function, some administrative functions. Each student may specify particular students or groups of students who may access his or her location. Tracking may be turned on and off in the short term for privacy, or when a student leaves town. A student may also revoke a particular tag issued to him or her, in case of loss or theft.
Tracking information must be timely. Timestamps must be accurate to within 10 seconds. Location records must be accessible (whether by query or callback) within a minute following the detection event. The system should be continuously available, with downtime never to exceed ten minutes in a single incident, and not to exceed 3 hours aggregated over an entire year.
It is up to you to determine what client devices are used for the interface. Different functions might be accessed with different devices: historical records, for example, might be available only on a desktop machine, whereas students might use handheld devices for queries and callbacks.
The system is intended for use at MIT. Your design may therefore take advantage of existing MIT infrastructure, such as Athena and zephyr.
Your paper must not exceed ten 11-point, single-spaced pages in length. Please use 1-inch margins. Don't forget to use diagrams where appropriate.
Your paper should be as long as is necessary to explain the problem, your solution, the alternatives you considered, and the reasons for your choices. It should be no longer than that. Again, please make sure your paper is no longer than ten pages.
A good paper begins with an abstract. The abstract is a very short summary of the entire paper. It is not an outline of the organization of the paper! It states the problem to be addressed (in one sentence). It states the essential points of your solution, without any detailed justification. And it announces any conclusions you have drawn. Good abstracts can fit in 100-150 words, at most.
The body of your paper should expand the points made in the abstract. Here you should:
Write for an audience consisting of colleagues who took 6.033 five years ago. That is, they understand the underlying system and network concepts and have a fair amount of experience applying them in various situations, but they have not thought carefully about the particular problem you are dealing with. Give enough detail that your design could be turned over to some programmers for implementation with some confidence that you won't surprised by the result.
When evaluating your report, your instructor will look at both content and writing.
Some content considerations:
If you have decided to propose your own application, you must submit the one page description of its goals and design issues by the beginning of recitation on Thursday, April 24th, 2003.
One page design outlines are due at the beginning of recitation on Tuesday, April 29th, 2003.
Your report is due at the beginning of recitation on Thursday, May 8th, 2003.
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