Jupiter System Gives Weather Forecasts by Phone

i/s Back Issues

Volume 14

No. 3 January/February 1999

Jupiter System Gives Weather Forecasts by Phone

Lee Ridgway

The following exchange may seem mundane, but one of the speakers &endash; Jupiter &endash; is no ordinary being.

Jupiter: Hi! This is Jupiter. How may I help you?

Caller: What's the forecast for Boston on Thursday?

Jupiter: In Boston Thursday, cloudy with periods of steady rain likely. High 43 and low 30. Is there something else you would like to know?

Caller: Is there snow in the forecast?

Jupiter: To my knowledge the forecast calls for no snow in Boston Thursday.

Jupiter is an experimental system that provides up-to-date weather forecasts over the phone. It is one of several projects of the Spoken Language Systems (SLS) Group in the MIT Lab for Computer Science. Other projects include Pegasus, for airline flight and gate information, and Voyager, for traffic conditions in the Boston area.

The SLS Group is headed by Victor Zue, Senior Research Scientist. Its aim is to provide universal access to computerized information via speech. To achieve this, SLS is developing a human-to-computer conversational interface that closely resembles natural, spoken language. This technology will enable us to talk with machines in much the same way that we talk to one another.

Behind-the-Scenes Technology
Jupiter relies on the complex interaction of high-speed, background computer processes, running on Pentium IIs. Here is a summary of the processes that are performed, in real time, for Jupiter to understand and respond to weather-related questions.

Speech recognition: the human speech is converted into a set of candidate sentence hypotheses.
Language understanding: the natural language component selects the most plausible hypothesis and converts it into a meaning representation, called a semantic frame, which contains the basic terms needed to query Jupiter's database of weather information.
Formal language generation: the semantic frame is used to build the query to the SQL database.
Information retrieval: the database query is executed and the requested information retrieved.
Natural language generation: the query result is converted into a weather report in natural English.
Information delivery: the report is synthesized into speech for delivery to the caller. Eventually, the system will be able to respond to, and in, languages other than English.

Jupiter, the first of the SLS projects to go public, can answer questions about weather conditions for over 500 cities worldwide (of which 350 are in the U.S.). The weather data comes from four different Web-based sources.

Talking to Jupiter
Using Jupiter is easy: you make a phone call and ask a question (weather- related, please!) in your natural voice. You don't need to pause unnecessarily between words (as with some voice dictation systems), over-enunciate, or speak in "computerese" (e.g., "weather Boston" instead of "What's the weather in Boston?"). Nor do you have to repeat details in follow-up questions that can be understood by context. If the system doesn't understand your question, it will say so. And if Jupiter misinterprets your question (it thought you said Austin), simply correct it ("No, I said Boston."). When you're done, hang up.

While Jupiter has a practical side for callers &endash; most of us do want to know about the weather somewhere &endash; it is still a research project in speech and language understanding. Callers need to realize that they are participants, albeit anonymous, in a large-scale public test. SLS records the calls to Jupiter to analyze how people talk to a computer and respond to its messages. Part of the analysis is to measure the error rate of the system, a reflection of how accurate it is at understanding what a caller said. So even if you don't get the information you want, unsuccessful queries help the researchers improve the technology.

Jupiter has been publicly available since May 1997, fielding about 100,000 queries since then. With a vocabulary of nearly 2000 words, correct understanding of weather queries is about 80% for novice users and over 95% for experienced users.

Pegasus Takes Flight
Just opened up for public testing is Pegasus, which maintains information on airline flights within the U.S. It can give information about the estimated departure and arrival times for flights that have either filed a flight plan or are in the air. In addition, Pegasus can tell you about actual arrival times for flights that have landed during the current day. To help callers who may not know the airline and number for a flight they are meeting, Pegasus also has information on schedules. A caller can ask about flights between two cities arriving at an approximate time. Pegasus responds with the possibilities, from which the caller selects a flight. The system then responds with up-to-the-minute arrival information from its database &endash; all in spoken dialog.

The researchers in SLS remind callers that because Pegasus is just starting up for public use, it is still somewhat fragile. At first, callers will probably help the researchers more than they get helped by the system. Over time, though, Pegasus should become more accurate in its understanding and reliable in its answers.

Details and Connections
For more details on how Jupiter and Pegasus work, see the Web sites listed below. The phone numbers for both services are also listed; the 800 numbers are toll free in North America.

Jupiter

http://www.sls.lcs.mit.edu/sls/whatwedo/applications/jupiter.html

Phone: 258-0300 or 1-888-573-8255

Pegasus

http://www.sls.lcs.mit.edu/sls/whatwedo/applications/pegasus.html

Phone: 258-6040 or 1-877-648-8255

For more information on the Spoken Language Systems Group, visit their site at
http://www.sls.lcs.mit.edu

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