Applications of Statistical Science

March 28, 2024

ABSTRACTS OF TALKS

Presented by The Fields Institute and the Statistics Department, University of Toronto


October 5th 1999
Probabilistic Networks and Expert Systems

Steffen Lauritzen, Department of Mathematics, Aalborg University

ABSTRACT

Bayesian and other probabilistic networks have now been established as a basic tool for decision support under uncertainty. The theory and methodology was developed in the late 80-s and exploits Markov properties for directed acyclic graphs in combination with old and new algorithms for local computation based on graph theory.

Microsoft Research has established a division to exploit such networks in the computer technology. Hewlett-Packard has instead invested in a research laboratory at Aalborg University and the Aalborg-company HUGIN Expert A/S.

Bayesian networks are for example used for diagnosis of printer errors, surveillance of steering rockets on the space shuttle, medical diagnosis and numerous other applications, for example decoding in noisy communication channels.

The lecture will attempt to convey important aspects of the theory and methodology and the corresponding algorithms, together with a few selected examples.


December 7th, 1999
Probabilistic and Statistical Techniques in Realistic Computer Graphics

Eugene Fiume, Department of Computer Science, University of Toronto


ABSTRACT
The use of probabilistic and statistical techniques has long had a place in computer graphics. I will give a short visual motivation for the use of these techniques in areas such as sampling and filtering for improved image quality, the use of (quasi-)Monte Carlo techniques for the computation of illumination integrals, and the use of stochastic methods for optimisation. I will then motivate the use of stochastic processes for the depiction of realistic natural phenomena such as smoke and fire. Some recent animations illustrating these concepts will also be shown.


February 1st 2000
Scaling Phenomena in Telecommunications

Murad Taqqu
Department of Mathematics, Boston University


ABSTRACT To appear.


March 7th, 2000
Two Timing: Politics and Response Latencies in a Bilingual Survey

Joseph F. Fletcher, Department of Political Science, University of Toronto

ABSTRACT
A new addition to the survey researcher's toolkit is the recording of how long it takes respondents to answer questions in an ordinary telephone survey. I will highlight some of the statistical techniques used in handling response time data as well as their substantive interpretation. Results obtained in a four-wave bilingual panel survey, showing improvements in the prediction of vote choice up to one year in advance of a federal election by using response latency data will be featured.
These results are achieved with conventional computer-assisted telephone interviewing (CATI) software, indicating that the immediate use of response time measures is both practical and attractive for commercial as well as academic survey units. Even so, response latencies are found to be sensitive to political circumstance such that timings must be analyzed separately for Anglophone and Francophone populations.


April 4th 2000
Smoothing techniques for surveys

James Stafford, Department of Public Health Sciences, University of Toronto

ABSTRACT
The graphical display of survey data leads naturally to reducing it to an aggregate form. For example, large data sets may be reported or displayed as a histogram where raw data has been reduced to a small number of bins and counts. Other examples include displays for scatterplot data, binary data and longitudinal data.

One approach to adapting modern graphical techniques for survey data is to simply apply them to this aggregate data. This may be the most useful approach if the aggregation of survey data renders it in a from for which modern graphical techniques were designed. These issues will be discussed in a non-technical way.