====== Speech and Language Understanding (SLU) 5 ECTS Prüfung 2021-10 ======

===== Meta Information =====
  * Subject: Speech and Language Understanding (SLU) 5 ECTS, Summer semester
  * Examiner: Prof. Andreas Maier
  * Evaluation
    * Atmosphere was quite relaxed
    * Prof. Maier gives hints in the lecture what is important! 
    * Very helpful to watch the videos/visiting the lecture.

===== Exam =====

* Summarize the lecture

> Mind Map

* Short overview about how do we percieve sounds & produce sounds?

> Description of ear / Fants Source Filter 

* About phonetics and phonemes, major classes and how do they look in the spectogram?

> Vowels, Fricatives, Plosives, Nasaln, Laterals...

* How to compute MFCCs?

> We have a signal, window it - calculate power spectrum - use Mel Filterbanks (25) - log - discrete cosine transform - use first 12 features. (Replace 0 frequency with energy of the signal) 

* Some follow up questions e.q. why windowing, why do the Filterbanks look like that.

> FT for pariodic signals; window allow us to interpret the short time as periodic. 
> Filterbanks design inspired by the Cholea 

* Talked about N-Grams (Zerogram, Monogram, etc. - Smoothing Backoff strategies)

* Explain Categories, how can they be used.

* Next question about Speaker Identification

> Explained UBM - GMM & MAP 

* Whats the difference between UBM + MAP & GMM for every Speaker with EM

* Last question: What is your favourite DL approach and explain it

> LSTM - made the drawing and explained it