12 research outputs found
Getting too personal(ized): The importance of feature choice in online adaptive algorithms
Digital educational technologies offer the potential to customize students'
experiences and learn what works for which students, enhancing the technology
as more students interact with it. We consider whether and when attempting to
discover how to personalize has a cost, such as if the adaptation to personal
information can delay the adoption of policies that benefit all students. We
explore these issues in the context of using multi-armed bandit (MAB)
algorithms to learn a policy for what version of an educational technology to
present to each student, varying the relation between student characteristics
and outcomes and also whether the algorithm is aware of these characteristics.
Through simulations, we demonstrate that the inclusion of student
characteristics for personalization can be beneficial when those
characteristics are needed to learn the optimal action. In other scenarios,
this inclusion decreases performance of the bandit algorithm. Moreover,
including unneeded student characteristics can systematically disadvantage
students with less common values for these characteristics. Our simulations do
however suggest that real-time personalization will be helpful in particular
real-world scenarios, and we illustrate this through case studies using
existing experimental results in ASSISTments. Overall, our simulations show
that adaptive personalization in educational technologies can be a double-edged
sword: real-time adaptation improves student experiences in some contexts, but
the slower adaptation and potentially discriminatory results mean that a more
personalized model is not always beneficial.Comment: 11 pages, 6 figures. Correction to the original article published at
https://files.eric.ed.gov/fulltext/ED607907.pdf : The Thompson sampling
algorithm in the original article overweights older data resulting in an
overexploitative multi-armed bandit. This arxiv version uses a normal
Thompson sampling algorith
Replicative aging impedes stress-induced assembly of a key human protein disaggregase
The collapse of protein homeostasis manifests itself in a toxic protein aggregation cascade, which is associated with degenerative diseases and aging. To solubilize aggregates, dedicated protein disaggregases exist in unicellular organisms, but these have no nuclear/cytosolic orthologs in metazoa. Alternative metazoan disaggregation machines have been described, but how these are operated and regulated in vivo remained unknown. We show that protein disaggregases are functionally diversified in human cells to efficiently target different types of stress-induced aggregates in sequential and temporally distinct phases. In particular, we show the selective assembly of an Hsp70-DNAJA1-DNAJB1 trimeric disaggregase that forms during late phase of stress recovery., i.e., after VCP-dependent solubilization of non-native proteins that accumulate in cellular condensates such as nucleoli or stress granules. When activated, the trimeric disaggregase provides resistance to stress toxicity and contributes to amyloid disposal. Strikingly, this disaggregase collapses early in cells undergoing replicative aging with important underlining pathophysiological consequences