dads1 2011 gerth stølting brodal
DESCRIPTION
dADS1 2011 Gerth Stølting Brodal. Introduction to Algorithms and Data Structures Students: 152 Lectures : 2+2 hours Use clickers at lectures (new in 2011) Theoretical TØ: 3 hours Weekly mandatory group handins datLAB : Students prepare handin - PowerPoint PPT PresentationTRANSCRIPT
dADS1 2011 Gerth Stølting Brodal
Introduction to Algorithms and Data Structures Students: 152 Lectures: 2+2 hours Use clickers at lectures (new in 2011) Theoretical TØ: 3 hours Weekly mandatory group handins datLAB: Students prepare handin Exam: Mix of multiple-choice & one-liners
dADS1 2011 – clicker experiencesGerth Stølting Brodal
Slides on course webpage – no clicker questions Slides with questions password protected after lecture
Number of questions: ~ 2 per lecture (45 min) Types of questions
Understanding of definitions Understanding of algorithms Constructive
Feedback – always shown to the students As expected Converged to wrong answer (good starting point for discussion) Question badly phrased (back to the drawing board...) No convergence (to hard?)
Software: PowerPoint (PresenterView) + TurningPoint AnyWhere
(I didn’t manage to embed into PowerPoint) Use two projectors in auditorium: 1) Background info 2) Question
Four examples from dADS1
1. QuickSort Lecture2. Union-Find lecture3. Interval tree lecture4. Amortized analysis lecture
... and an example from an UNF talk
Is the answer A or B ?
a) Answer Ab) Answer Bc) Don’t know
Is the answer A or B ?
a) Answer Ab) Answer Bc) Don’t know
Sandsynlighedsteori Baggrund?
a) Ingenb) Gymnasietc) Gymnasiet + Universitetetd) Universitetete) Andet stedsf) Ved ikke
Sandsynligheden for at slå krone1/2
EksperimentKast en Mønt
a) Platb) Kronec) På højkantd) Ingen mønt
EksperimentAntal kast før man får krone ?
12345678
9 eller flere
a) 1b) 2c) 3d) 4e) 5f) 6g) 7h) 8i) 9 eller flere
a) 1b) 2c) 3d) 4e) 5f) 6g) 7h) 8i) 9 eller flere
Sætning
Forventede antal kast for at få krone = 2
Bevis
□
22
1
2
1
2
111
1
i
i
i
i
ii
s.s. for i’te kast er krone s.s. for først i-1 kast er plat# kast
EksperimentAntal kast før man får krone ?
1st vote
abcdefghi
2nd vote
abcdefghi
Union-Find
Interval Tree 1st vote
abcdef
2nd vote
abcdef
1st vote
abcde
2nd vote
abcde
Amortized Analysis
Google PageRankTM
Metode RandomSurferStart på knude 1Gentag mange gange:
Kast en terning:Hvis den viser 1-5:
Vælg en tilfældig pil ud fra knudenved at kaste en terning hvis 2 udkanter
Hvis den viser 6:Kast terningen igen og spring hen til den knude som terningen viser
Metode RandomSurferStart på knude 1Gentag mange gange:
Kast en terning:Hvis den viser 1-5:
Vælg en tilfældig pil ud fra knudenved at kaste en terning hvis 2 udkanter
Hvis den viser 6:Kast terningen igen og spring hen til den knude som terningen viser
Google PageRankTM
Simpel Webgraf — SandsynlighedsfordelingSkridt 1 2 3 4 5 6
0 1.000 0.000 0.000 0.000 0.000 0.0001 0.028 0.861 0.028 0.028 0.028 0.0282 0.039 0.109 0.028 0.745 0.039 0.0393 0.039 0.432 0.028 0.118 0.338 0.0444 0.039 0.299 0.028 0.388 0.077 0.1695 0.039 0.406 0.028 0.277 0.189 0.0606 0.039 0.316 0.028 0.366 0.143 0.1077 0.039 0.373 0.028 0.291 0.180 0.0878 0.039 0.342 0.028 0.339 0.149 0.1039 0.039 0.361 0.028 0.313 0.169 0.090
10 0.039 0.348 0.028 0.329 0.158 0.09811 0.039 0.357 0.028 0.318 0.165 0.09412 0.039 0.351 0.028 0.325 0.160 0.09613 0.039 0.355 0.028 0.320 0.163 0.09414 0.039 0.352 0.028 0.323 0.161 0.09615 0.039 0.354 0.028 0.321 0.163 0.09516 0.039 0.353 0.028 0.323 0.162 0.09517 0.039 0.354 0.028 0.322 0.162 0.09518 0.039 0.353 0.028 0.322 0.162 0.09519 0.039 0.353 0.028 0.322 0.162 0.09520 0.039 0.353 0.028 0.322 0.162 0.09521 0.039 0.353 0.028 0.322 0.162 0.09522 0.039 0.353 0.028 0.322 0.162 0.09523 0.039 0.353 0.028 0.322 0.162 0.09524 0.039 0.353 0.028 0.322 0.162 0.09525 0.039 0.353 0.028 0.322 0.162 0.095
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My conclusions about using clickers...
Gives students time to understand the important concepts
Helps me reflect on my lectures Much better feeling where the students are Use 2-3 hours per double lecture adding slides