Use of cumulants to quantify uncertainties in the HBT measurements of the homogeneity regions

Let us denote p(x|K) the space density of the points where identical particles of some kind, e.g. pi+ mesons, with momentum K are produced. When using the HBT method to determine p(x|K) one encounters ambiguities. We show that these ambiguities do not affect the even cumulants of the distribution p(x|K). In particular, the HBT radii of the homogeneity regions, which are given by the second order cumulants, and the distribution of distances between the pairs of production points for particles with momentum K can be reliably measured. The odd cumulants are ambiguous. The are, however, correlated. In particular, when the average position (K) is known as a function of K there is no further ambiguity.Comment: LateX, 10 pages, no figure

Ambiguities in the HBT approach to determine the interaction regions

The necessary and sufficient condition for a quantity to be measurable by the HBT method is given and discussed.Comment: Report at the conference QCD08, July 2008, LateX 8 pages, no figure

FairFuzz: Targeting Rare Branches to Rapidly Increase Greybox Fuzz Testing Coverage

In recent years, fuzz testing has proven itself to be one of the most effective techniques for finding correctness bugs and security vulnerabilities in practice. One particular fuzz testing tool, American Fuzzy Lop or AFL, has become popular thanks to its ease-of-use and bug-finding power. However, AFL remains limited in the depth of program coverage it achieves, in particular because it does not consider which parts of program inputs should not be mutated in order to maintain deep program coverage. We propose an approach, FairFuzz, that helps alleviate this limitation in two key steps. First, FairFuzz automatically prioritizes inputs exercising rare parts of the program under test. Second, it automatically adjusts the mutation of inputs so that the mutated inputs are more likely to exercise these same rare parts of the program. We conduct evaluation on real-world programs against state-of-the-art versions of AFL, thoroughly repeating experiments to get good measures of variability. We find that on certain benchmarks FairFuzz shows significant coverage increases after 24 hours compared to state-of-the-art versions of AFL, while on others it achieves high program coverage at a significantly faster rate

Missile Defence: A View from Turkey. CEPS Commentaries, 12 October 2009

On September 9th, the United States announced that it was planning a multi-billion dollar sale of 13 Patriot fire units, 72 PAC-3 missiles and a range of related hardware for ground-based air defence to Turkey. The decision, some commentators reasoned, was evidence that the US was turning to Turkey as an alternative base for the missile defence system (MDS) originally planned in Central Europe. Such assessments proved somewhat off the mark, however. What is on sale to the Turks (a system to protect Turkey against short- and medium-range missiles), it turns out, is different from what had been on offer to the Czechs and Poles, which was a system designed to intercept intercontinental ballistic missiles. The announced sale of one system, however, signalled the end of the other. On September 17th, the Obama administration confirmed it would abandon plans for an MDS based in Poland and the Czech Republic. In this Commentary, journalist and researcher Piotr Zalewski (Istanbul) assesses the implications of this move for Turkish-US relations and their neighbours and allies