Given the amount of documents that I deal with, I’ve had many opportunities to save paper if only I could annotating on a PDF directly. Until recently, Jarnal has been the only free solution on Windows. However, I would say that Jarnal is not exactly the most polished piece of software I have used… (But I am not complaining against its price.)
Well, Jarnal has some serious competition now. PDF-XChange Viewer is a free (as in beer) PDF viewer that supports a full suite of native PDF annotation capabilities. By “native”, I mean if you insert a “sticky note” comment into the PDF, it shows up as a sticky note in Adobe Reader and so you can open, close and move the note, just like the stickies created by Acrobat Professional. In comparison, the interface is not very customizable and the keyboard shortcuts are not quite “there” yet, but it is certainly looking very good for a version-1 product. The font rendering is not as good as well, but it is comparable to other free solutions. Its performance on graphics intensive PDF is very good on too! There is even a button that allows you to quickly open the current PDF using Adobe Reader, just in case.
I wish it has better ink support, but again, I am not complaining against its price. 
P.S. Not that I really want to destroy any sales, but I note that PDFCreator is a very good Distiller replacement. Together with PDF-XChange Viewer, they cover most of my PDF needs.
Name: Willem-Jan van Hoeve
University: Carnegie Mellon University
Date: November 2, 2007
Time: 1:30 to 3:00 pm
Location: 388 Posner Hall
Title: Algorithms in Constraint Programming: the Sequence Constraint
Abstract:
Constraint Programming is a powerful and flexible paradigm to model and solve combinatorial problems. In contrast to traditional optimization techniques that reason on the problem as a whole, constraint programming reasons on tractable substructures of the problem individually. More specifically, the search space is reduced by filtering out inconsistent domain values from the variable domains. The challenge is to find efficient filtering algorithms for combinatorial structures that occur frequently in applications. In this talk we consider a combinatorial structure known as the “sequence constraint”, that appears in many applications, such as car manufacturing and nurse rostering. After its introduction in 1988 several filtering algorithms have been proposed for it, none of which removed all possible inconsistent domain values, however. We present three filtering algorithms, including the first algorithm that achieves complete filtering in polynomial time for this constraint. We also provide experimental results, showing the effectiveness of our filtering algorithms in practice. This is joint work with Gilles Pesant, Louis-Martin Rousseau and Ashish Sabharwal. It was awarded as best paper at the annual conference on constraint programming CP 2006 (out of 142 submissions).
