activity
20182020
most citedDetecting Ghostwriters in High Schools

3 citations · 4 across the 2 of their papers we have counts for

collaborators

6 papers

cs.LG2020

Second Order PAC-Bayesian Bounds for the Weighted Majority Vote

Andrés R. Masegosa, Stephan S. Lorenzen, Christian Igel +1

We present a novel analysis of the expected risk of weighted majority vote in multiclass classification. The analysis takes correlation of predictions by ensemble members into acco…

cs.CY2019

Tracking Behavioral Patterns among Students in an Online Educational System

Stephan Lorenzen, Niklas Hjuler, Stephen Alstrup

Analysis of log data generated by online educational systems is an essential task to better the educational systems and increase our understanding of how students learn. In this st…

cs.DB2019

Revisiting Wedge Sampling for Budgeted Maximum Inner Product Search

Stephan S. Lorenzen, Ninh Pham

Top-k maximum inner product search (MIPS) is a central task in many machine learning applications. This paper extends top-k MIPS with a budgeted setting, that asks for the best app…

cs.CY20191 cited

Investigating Writing Style Development in High School

Stephan Lorenzen, Niklas Hjuler, Stephen Alstrup

In this paper we do the first large scale analysis of writing style development among Danish high school students. More than 10K students with more than 100K essays are analyzed. W…

cs.CL20193 cited

Detecting Ghostwriters in High Schools

Magnus Stavngaard, August Sørensen, Stephan Lorenzen +2

Students hiring ghostwriters to write their assignments is an increasing problem in educational institutions all over the world, with companies selling these services as a product.…

cs.LG2018

On PAC-Bayesian Bounds for Random Forests

Stephan Sloth Lorenzen, Christian Igel, Yevgeny Seldin

Existing guarantees in terms of rigorous upper bounds on the generalization error for the original random forest algorithm, one of the most frequently used machine learning methods…