Elyot Grant is giving a talk on Tuesday July 20th at 4:30pm in MC2066. The
information follows below: Title: The Incompressibility Method Abstract:
Heapsort. It runs in $\Theta(n \log n)$ time in the worst case, and in
$O(n)$ time in the best case. Do you think that heapsort runs faster than
$O(n \log n)$ time on average? Could it be possible that on most inputs,
heapsort runs in $O(n)$ time, running more slowly only on a small fraction
of inputs? Most students would say no. It "feels" intuitively
obvious that heapsort should take the full $n \log n$ steps on most inputs.
However, proving this rigourously with probabilistic arguments turns out to
be very difficult. Average case analysis of algorithms is one of those icky
subjects that most students don't want to touch with a ten foot pole; why
should it be so difficult if it is so intuitively obvious? In this talk, we
shall explore the incompressibility method---an interesting and extremely
powerful framework for determining the average-case runtime of algorithms.
Within the right background knowledge, the heapsort question can be answered
with an elegant 3-line proof. The crucial fact is that an overwhelmingly
large fraction of randomly generated objects are incompressible. We can show
that the inputs to heapsort that run quickly correspond to inputs that can
be compressed, thereby proving that heapsort can't run quickly on average.
Of course, "compressible" is something that must be rigourously
defined, and for this we turn to the fascinating theory of Kolmogorov
complexity. In this talk, we'll briefly discuss the proof of the
incompressibility theorem and then see a number of applications. We won't
dwell too much on gruesome mathemtical details. No specific background is
required, but knowledge of some of the topics in CS240 will be helpful in
understanding some of the applications.
Edgar Bering will be giving a talk tomorrow in MC2066 at 4:30pm.
Title: Halftoning and Digital Art
Abstract:
Halftoning is the process of simulating a continuous tone image with small dots
or regions of one colour. Halftoned images may be seen in older newspapers with
a specled apperance, and to this day colour halftoning is used in printers to
reproduce images. In this talk I will present various algorithmic approaches to
halftoning, with an eye not toward exact image reproduction but
non-photorealistic rendering and art. Included in the talk will be an
introduction to digital paper cutting and a tutorial on how to use the CSC's
paper cutter to render creations.
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Brennan Taylor b4taylor at uwaterloo dot ca
Computer Science Club http://csclub.uwaterloo.ca/~b4taylor
University of Waterloo Waterloo, Ontario CANADA N2L 3G1
There is a CSC Code Party Friday starting at 7:00PM (1900) until we get bored (likely in the early in morning). Come out for fun hacking times.
--
Brennan Taylor b4taylor at uwaterloo dot ca
Computer Science Club http://csclub.uwaterloo.ca/~b4taylor
University of Waterloo Waterloo, Ontario CANADA N2L 3G1
The question has been passed onto us here at the CSC. How do students want to
hear about the opportunities they have for their upper-year education?
In the past a number of approaches have been attempted:
1) Professors teaching the classes will give a 10 minute introduction and answer
questions.
2) Students will answer questions and talk about their experiences.
3) A couple of Professors will talk about upper-year courses in general.
How would you like to hear about the upper-year courses?
Do you want to know the horrors of Real-Time? The shininess of Graphics? The
ridiculous things compiler writers do?
Send your responses to veep(a)csclub.uwaterloo.ca please!
--
Brennan Taylor b4taylor at uwaterloo dot ca
Computer Science Club http://csclub.uwaterloo.ca/~b4taylor
University of Waterloo Waterloo, Ontario CANADA N2L 3G1
Tell your friends!
Again the talk is Tuesday July 6th, 4:30pm in MC2054.
Nomair A. Naeem - Dataflow Analysis
=== Abstract
After going through an introduction to Lattice Theory and a formal
treatment to Dataflow Analysis Frameworks, we will take an in-depth
view of the Interprocedural Finite Distributive Subset (IFDS) Algorithm which
implements a fully context-sensitive, inter-procedural static dataflow
analysis. Then, using a Variable Type Analysis as an example, I will outline
recent extensions that we have made to open up the analysis to a larger variety
of static analysis problems and making it more efficient.
The talk is self-contained and no prior knowledge of program analysis is
necessary.
--
Brennan Taylor b4taylor at uwaterloo dot ca
Computer Science Club http://csclub.uwaterloo.ca/~b4taylor
University of Waterloo Waterloo, Ontario CANADA N2L 3G1