- Wow, he sounds pretentious 
- Modality: way to express or perceive?
Spectrum: raw modalities (speech signal, image,) vs Abstract modalities ()
- Multimodal
- Heterogeneous vs heterogeneous
- Dimensions of heterogeneity
+ element representation: dicrete, conti, ..
+ element distribution: density, frequency,
+ structure: temporal, spatial, ...
+ information: abstraction, entropy
+ noise: 
+ relevance: task, convex, 

- Connected modalities: shared information that 
+ statisical - dependency (association), semantic - relationship(correspondence)
- Interacting modalities: representation fusion, reducndancy or nonreducndancy, one mode changes the other, 

Challenges:
- representation and alignment
- fusion: linear, multicative (kind of a simple nonlinear), and then other heuristic architecture (gate, ...)
question is: why human heuristic should work? is it because it is compact?
