Archive for September, 2021

DISA Seminar October 4th on Aggregation as Unsupervised Learning and some of its Applications

Friday, September 24th, 2021
  • When? October 4th 12-13
  • Where? Online – the link will be sent to those who sign up
  • Registration? Sign up via this link no later than October 3rd.

This seminar will be presented by the DISTA research group within DISA, you will meet and listen to Welf Löwe, Maria Ulan, Morgan Ericsson, Anna Wingkvist

Aggregation combines several independent variables to a dependent variable. The independent variables are different, possible mutually dependent observations of a real world. The dependent variable should preserve properties of the independent variables, e.g., the ranking or relative distance of the independent variable tuples, and ultimately the properties of the real world. However, while there usually exist large amounts independent variable tuples, there is no ground truth data available mapping these tuples to the corresponding dependent variable values. This makes aggregation an unsupervised machine learning problem, as opposed to, e.g., regression where data comprises independent variable tuples and the corresponding dependent variable values.

Instances of the problem frequently occur in software engineering, e.g., when trying to assess the quality of software by metrics. Metrics (independent variables) can easily be measured for a lot of software artifacts, but it is hard to measure quality (dependent variable). Instances also occur in many other assessment situations including, but not limited to the assessment of project proposals, financial investments, and human movements.

In our talk, we present
1) aggregation as unsupervised learning including unweighted and weighted approaches
2) ways to evaluate and compare different aggregation approaches including an evaluation of the approaches introduced in 1)
3) applications to software engineering problems applying the evaluation introduce in 2)

 

NEW DISA Seminar Series starting September 6th 12-13

Thursday, September 2nd, 2021

We are now finally starting a new Seminar series within DISA, even if you are not affiliated with DISA you are welcome to attend.

Aim with the seminar series:
Our research centre now have some 10 different research groups, each comprising a trending research topic. In order to make those different subjects of expertize more known outside of the own group and more accessible to PhD students we now launch a research seminar series.

Out first lunch seminar series will be on Monday September 6th 12-13 with Thomas Holgersson
Link to the seminar: https://lnu-se.zoom.us/j/63536937748 (no sign up needed)

Titel: Matrices in different dimensions: high, low and in between
Abstract: I will survey some common methods for statistical analysis of random matrices in fixed and in increasing dimensions. The geometry of high-dimensional objects will discussed from a data-analytic perspective. I will also cover some different modes of asymptotics, with particular focus on scalability.
Keywords: Wishart ensambles, geometry of high-dimensional objects, spectral analysis, Mahalanobis distance, modes of convergence.

Kind regards,
Thomas and Diana