David Siegel - The Plenitude of Arboreal Beauty

After spending eight months on GNOME Do, I gave a brief presentation (followed by a great, not-so-brief Q&A session) to an auditorium full of Computer Science students and faculty. In the presentation, I discuss five “rules” explicitly and implicitly imposed in undergraduate Computer Science coursework that I had to break in order to create GNOME [...]

Abstract
The typical computer user interacts with a number of different resources on her computer. These resources are accessed via many interfaces, including menus, location bars, icons, file browsers, and shortcut keys. We plan to consolidate these interfaces by creating an application that indexes items found in the user’s desktop environment (e.g. documents, contacts, applications, multimedia) [...]

In an article entitled Computing Machinery and Intelligence, Alan Turing describes the Turing test, his famous criterion for machine intelligence: a computer can be considered a thinking machine if a human interlocutor, after asking the computer a series of questions, cannot tell whether he is conversing with a machine or with another human. After describing [...]

I’m really fortunate to be taking some amazing courses from some awesome professors in my last semester as an undergrad at Penn; I’m taking a course on technology and policy from Matt Blaze, and another course on functional programming from Benjamin Pierce. After only a couple lectures from Matt Blaze on technology and privacy, I’ve [...]

Here’s a neat little algorithm written in python to merge k sorted lists in O(nlogk) time using a k-element min-heap:
# Lists is an array of sorted lists (arrays):
#   [ [...], [...], … ]
def ListMerge(Lists):
  # The number of elements awaiting merge in each list.
  sizes = [len(L) for L in Lists]
  # Create a heap with a slot [...]

Wanting to re-familiarize myself with Objective-C, I wrote a mergesort method in an NSArray category:
- (NSArray*)mergeSortArrayUsingSelector:(SEL)comparator
{
  id buf[[self count]];
  [self getObjects:buf];
  mergesort_(buf, [self count], comparator);
  return [NSArray arrayWithObjects:buf count:[self count]];
}