23 November 2009 @ 12:23 pm
As most of you know there are 7 problems worth $1,000,000 (see here). It may be just 6 since Poincare's conjecture has probably been solved. Why are these problems worth that much money? There are other open problems that are worth far less money. What determines how much money a problem is worth?

When Erdos offered money for a problem (from 10 to 3000 dollars) I suspect that the amount of money depended on (1) how hard Erdos thought the problem was, (2) how much Erdos cared about the problem, (3) how much money Erdos had when he offered the prize, and (4) inflation. (If anyone can find a pointer to the list of open Erdos Problems please comment and I'll add it here.)

Here is a problem that I have heard is hard and deep, yet it is only worth $3000 (Erdos proposed it). I think that it should be worth more.

BACKGROUND: Szemeredi's theorem: Let A&sube N. If the limit as n goes to infinity of size(A &cap {1,...,n})/n is bounded below by a positive constant then A has arbitrarily long arithmetic sequences. Intuition: if a set is large then it has arb long arith seqs. The CONJECTURE below uses a diff notion of large.

CONJECTURE: Let A&sube N. If &suma&isin A 1/a div

KNOWN: Its known that if A is the set of all primes (note that &suma&isin A 1/a diverges) then A has arbitrarily large arithmetic progressions. Nothing else is known! The conjecture for 3-AP's isn't even known!

Is this a good problem? If it is solved quickly (very unlikely) than NO. If absolutely no progress is made on it and no interesting mathematics comes out of the attempts than NO. It has to be just right.
 
 
Recently, Dario Fiore and Rosario Gennaro proposed the IB-KA protocol, which was inspired by MQV protocol. They provide a full
proof of security of IB-KA protocol using techniques developed by
Krawczyk in the Canetti-Krawczyk model. They designed the IB-KA
protocol with some security properties such as perfect forward
secrecy, reflection attack resilience, and key compromise impersonation resilience. But they didn't consider ephemeral key
compromise problem in the design of IB-KA protocol, and made no
analysis whether the IB-KA protocol can resist ephemeral key
compromise attacks. In this paper, we present ephemeral key
compromise attack on the the IB-KA protocol. Our work shows that the
IB-KA protocol is designed without ephemeral key compromise
resilience.
 
 
Recently, the $C^{*-}$ signature scheme has been completely broken by Dubois et al. (Dubois et al., CRYPTO and EUROCRYPT 2007). As a consequence, the security of SFLASH and other multivariate public key systems have been impaired. The attacks presented in (Dubois et al., CRYPTO and EUROCRYPT 2007) rely on a symmetry of the differential of the encryption mapping. In (Ding et al., 2007), Ding et al. experimentally justify the use projection as a method of avoiding the new attack. In this paper, we derive some properties of the discrete differential, give a theoretical justification for the reparation in (Ding et al., 2007), and establish the exact context in which this attack is applicable.
 
 
We propose new cryptosystems based on self-distributive systems that
are defined over conjugate operations on noncommutative groups. Under certain assumptions, our basic scheme is proven to be indistinguishable against chosen plaintext attacks (IND-CPA), and the extend version is IND-CCA secure. When braid groups are taken into consideration, we derive a new braid-based encryption scheme that is directly based on the intractability assumption of the conjugator search problem in braid groups. Furthermore, we quote an analysis to manifest that our proposal has the potential to resist currently known quantum attacks.
 
 
This paper describes an extremely efficient squaring operation in the so-called `cyclotomic subgroup' of $\F_{q^6}^{\times}$, for $q \equiv 1 \bmod{6}$. This result arises from considering the Weil restriction of scalars of this group from $\F_{q^6}$ to $\F_{q^2}$, and provides efficiency improvements for both pairing-based and
torus-based cryptographic protocols.
 
 
23 November 2009 @ 09:21 am
She sensed me taking pictures of her, and we struck up a conversation. The first one shows the Richmond /San Rafael Bridge. She was wondering what the big buildings were on the western end of the bridge, and I told her it was San Quentin Prison. She started snapping away.

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A little while later as we were approaching San Francisco, she wondered what that island was out there, with the buildings... "Who lives there?"
"Alcatraz", I said. "Nobody."

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23 November 2009 @ 09:55 am
  • (This is an edited repost of one of the posts from the earlier version of my Haskell tutorial.)
  • (This file is a literate haskell script. If you save it as a file whose name ends in ".lhs", it's actually loadable and runnable in GHCI or Hugs.)

Like any other modern programming language, Haskell has excellent support for building user-defined data types. In fact, even though Haskell is very much not object-oriented, most Haskell programs end up being centered around the design and implementation of data structures, using constructions called classes and instances.

In this post, we're going to start looking at how you implement data types in Haskell. What I'm going to do is start by showing you how to implement a simple binary search tree. I'll start with a very simple version, and then build up from there.

Read the rest of this post... | Read the comments on this post...
 
 
23 November 2009 @ 10:10 am

I repeat: Skepticon II was a blast, and I think what really contributed to the fun was that there was a lot of young people organizing it and in the audience, and no stodginess was allowed. Make sure you go next year — it really was one of the more entertaining and enthusiastic meetings I've gone to this year…and it was held in the heart of the Bible Belt, in the city otherwise best known as the capitol of the AssGod church.

I have to answer a couple of questions I was asked repeatedly. I dazzled everyone with my sartorial flamboyance, and on the first night I wore my infamous crocoduck tie. I'm sorry, you can't get it, at least not yet. Josh Timonen had it made, and so far, only Richard Dawkins and I have one. Maybe it will show up in the RDF store someday, or maybe it won't.

On the second day, I was asked about the Creation "Museum", and ripped open my shirt to reveal a portrait of the epic battle that was waged on our visit. People asked where they could get that, too (although one audience member showed me hers — she'd already got one). This one is easy.

pz_dj.jpeg
PZ Myers, DJ Grothe

Just go to Jen's store, and you can order them right now. You can also get it on a black shirt, too.

You'll have to get your own boy toy, though.


By the way, the photograph is by Ziztur — who has a nice blog.

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23 November 2009 @ 02:51 pm

Things evidently went extremely well over the weekend at the LHC, with simultaneous circulating beams achieved this morning. Speculation is that first collisions (at the injection energy of 450 GeV/beam) are imminent. Places for up to the minute information include here, here and here.

Update: It looks like first collisions have been seen at the LHC. Announcement comes from a muzzled blogger….

Update: Modified posting title.

 
 
 
Vercauteren introduced
a notion of optimal pairings. Up to know the only known optimal
pairing is the optimal Ate pairing. In this paper, we give some
properties of optimal pairing and provide an algorithm for finding
an optimal pairing if there exists one which is defined on the given
elliptic curve. Applying the cyclotomic polynomial, we construct
some new optimal pairings and provide a construction method of
pairing-friendly elliptic curves on which the optimal pairing can be
defined. Our algorithm is explicit and works for arbitrary embedding
degree $k$ and large prime subgroup orders $r$.
 
 
For a prime $p$ with $p\equiv 3\,({\rm mod}\, 4)$ and an odd number
$m$, the Bentness of the $p$-ary binomial function $f_{a,b}(x)={\rm
Tr}_{1}^n(ax^{p^m-1})+{\rm Tr}_{1}^2(bx^{\frac{p^n-1}{4}})$ is
characterized, where $n=2m$, $a\in \bF_{p^n}^*$, and $b\in
\bF_{p^2}^*$. The necessary and sufficient conditions of
$f_{a,b}(x)$ being Bent are established respectively by an
exponential sum and two sequences related to $a$ and $b$. For the
special case of $p=3$, we further characterize the Bentness of the
ternary function $f_{a,b}(x)$ by the Hamming weight of a sequence.
 
 
23 November 2009 @ 07:24 am

I would sure like to know more about this:

Top code-breakers at the Government Communications Headquarters in the United Kingdom have succeeded in breaking the secret language that has allowed imprisoned leaders of al-Qaida to keep in touch with other extremists in U.K. jails as well as 10,000 "sleeper agents" across the islands....

[...]

For six months, the code-breakers worked around the clock deciphering the code the three terrorists created.

Between them, the code-breakers speak all the dialects that form the basis for the code. Several of them have high-value skills in computer technology. The team worked closely with the U.S. National Security Agency and its station at Menwith Hill in the north of England. The identity of the code-breakers is so secret that not even their gender can be revealed.

"Like all good codes, the one they broke depended on substituting words, numbers or symbols for plain text. A single symbol could represent an idea or an entire message," said an intelligence source.

The code the terrorists devised consists of words chosen from no fewer than 20 dialects from Afghanistan, Iran, Pakistan, Yemen and Sudan.

Inserted with the words ­ either before or after them ­ is local slang. The completed message is then buried in Islamic religious tracts.

 
 

datamorphose.jpg
dataMorphose [christianekeller.de] is a series of amazingly beautiful and sophisticated physical data sculptures which represent information by the shape and motion of sail-like tensile structures.

Each triangular canvas represents a separate data object. Its data values are conveyed by the tension of the canvas, which in turn determines its size, movement and position in space. One vertex of each canvas is attached to the ground floor of a transparent cube, so that each canvas can receive its meaning through the projection of words and numbers onto that area. In all, this means the user is required to learn the visual language in order to understand the visualization, which is claimed to be intuitive to learn.

One sculpture visualizes the current time. The hours, minutes and seconds are assigned to one sail respectively. To represent the hours, the central canvas changes its position in space. The other two sails visualize the values from 0 - 59 by changing their shape: one vertex moves along the vertical edge of the cube: the downward movement shows the values from 0 - 29, the upward movement the values from 30 - 59. The second sculpture conveys web traffic data through the motion of 4 sails: the faster a canvas moves the higher the activity of the website or the search term. The last sculpture shows statistical information by a succession of 5 sails.

Technically, nylon threads are attached on the vertices of the canvas, which lead down into the base and are moved by servo motors according to the data values. You can watch them move in the documentation video below.

Reminded me of Level Green and Pulsating Emotion Visualization Organism.


 
 
 
23 November 2009 @ 12:01 am
  • 06:53 @jefferickson I'm all about the surprising connection. Which way you choose to read the relation is up to you. #
  • 12:51 Of COURSE! Google is the modern Delphi. You can ask the oracle, and she will know EVERYTHING, but she only answers what you actually ask!! #
  • 13:01 *groan* I'm not quite up to Delta Elite status. I'm missing ... get this ... 22 miles!!! I'll get them on my way back to SF, sure, but 22!!! #
  • 17:09 Feeling extraordinarily *meh* tonight. And I have no idea why. Quite annoying. #
  • 19:56 My dear wife, after watching "Mr Smith goes to Washington", with utter surprise: "This was actually good!!?!" #
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23 November 2009 @ 04:10 pm

cost_of_health_care.jpg
"The Cost of Getting Sick" [ge.com] is a a new data visualization tool developed in collaboration with Ben Fry, Director of Seed Visualization. It enables the exploration of some the 6 million patient records currently stored in GE's proprietary electronic medical records database.

The online interactive tool allows users to slide a bar to select one's age and then select parts of the pie chart in order to investigate a more complete picture of the actual costs associated with a wide range of chronic conditions such as diabetes, asthma, depression, and hypertension.

A short, slick interview with Ben Fry regarding GE's two recent data visualizations can be watched below.

See also Visualizing the Major Health Issues Facing Americans Today and On the Origin of Species.


 
 
23 November 2009 @ 05:26 am

What caused this outburst of V838 Mon?  What caused this outburst of V838 Mon?


 
 
22 November 2009 @ 11:02 pm

Once again, I risk stirring envy by putting a picture of a kitty-cat on Pharyngula. I met some people who showed me a nice picture of their pet, which is named after…me!

Here's PZ Meowers:

pz_meowers.jpeg

And look! He's blogging!

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