Sunday, June 24, 2007

 

Reading Between the Lines: a trilemma

It seems the French SGDN has said too much or too little. How confident are they that the encryption used by BlackBerry is too weak for government use? Why? I can think of three possibilities, and no way to decide among them:
  1. They (the French intelligence services) know the NSA can decrypt BlackBerry messages, either because they've been so informed, or because they (the French) can do it and so assume the NSA can too. This could be by a "backdoor", not necessarily by cracking codes.
  2. They can't decrypt the messages, and don't want government officials communicating with messages that can't be monitored. Historically (recent history), the French agencies have used "tableau d'écoute" (wiretaps) fairly often, and not necessarily with official authorisation or awareness.
  3. They presume that RIM will tell the NSA or Homeland Security whatever they "need" to know.

.Press clippings:
  • France bans BlackBerrys over fears of US intelligence snooping
    Seven million people worldwide may be addicted to them but the French government has said "non" to Le BlackBerry, fearing US intelligence agents could be snooping on state secrets.

    "The risks of interception are real. It is economic war," Alain Juillet, who is in charge of economic intelligence for the government, told Le Monde newspaper.

    The concern is that information sent from a BlackBerry gets routed via servers in the United States and Britain, and that this poses "a problem with the protection of information".

    Research In Motion, the company that makes the handheld devices, poured cold water on the French fears, saying there was no way that the US National Security Agency could see the content of messages that were transmitted .

    But Paris is clearly not convinced. France's General Secretariat for National Defence first declared the ban on BlackBerrys 18 months ago but recently had to send out another reminder.
  • La complainte du Blackberry dans les ministères

    Extrait : Une complainte récurrente monte, depuis la présidentielle, au sein des cabinets ministériels, à Matignon et à l'Elysée : l'interdiction d'utiliser le Blackberry, un assistant personnel permettant de téléphoner et de recevoir des courriers électroniques ( Le Monde du 9 juin). Débauchés dans des banques d'affaires, des cabinets d'avocats et des entreprises, ils n'en reviennent toujours pas. « On a le sentiment de perdre un temps fou, il faut réapprendre à travailler à l'ancienne, en fait de rupture, on vit plutôt une fracture technologique », s'exclame ce directeur de cabinet d'un grand ministère.
  • BlackBerry fools
    No addict enjoys the experience of cold turkey, even if the addictive substance is a handheld e-mail device. French officials seem to be no exception. The French security ministry, the SGDN, has warned incoming French cabinet ministers that they must quit the BlackBerry habit because US spies may be able to intercept their e-mailed communiqués. BlackBerry’s Canadian maker, Research in Motion Ltd, denies that there is any such risk. Officials complain that the SGDN is stuck in the past.
  • Les ministères se méfient des agendas électroniques
    Une circulaire interdisant l'usage des PDA dans les cabinets ministériels, à Matignon et à l'Elysée viendrait d'être renouvelée par le Secrétariat général de la défense nationale, qui souligne qu'aucun de ces appareils ne sécurise les données de façon totalement fiable ...
  • BlackBerry users warned of spying
    From Times Wire Reports -- June 21, 2007

    French government defense experts have advised against use of BlackBerry communication devices in government offices, reportedly to avoid snooping by U.S. intelligence agencies.

    E-mails sent from "Le BlackBerry" pass through servers in the United States and Britain, and France fears that makes the system vulnerable to snooping by the U.S. National Security Agency, Le Monde reported.

    Research in Motion, the company that makes BlackBerrys, denies that such spying is possible.
  • France Asks Top Officials To Banish BlackBerrys
    Associated Press
    Word Count: 296 | Companies Featured in This Article: Research In Motion

    PARIS -- French government defense experts have advised officials in France's corridors of power to stop using BlackBerry, reportedly to avoid snooping by U.S. intelligence agencies.

    Le Monde newspaper, which broke the story, described BlackBerry withdrawal among those who have given them up. "We feel that we are wasting huge amounts of time, having to relearn how to work in ...

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Sunday, June 10, 2007

 

A Frivolous Search Engine Query

I have "song stuck in head" today. I once saw a web site that provided help for that; I think it suggested another song to substitute; I'll look for it in a little while (I apparently didn't bookmark it, or if I did I didn't choose good tags for finding it again). Meanwhile, the song is Frank Zappa's "No way to delay that trouble coming every day." I suppose it is all the fuss about "Sgt. Pepper's" that brought it to mind: "A Day in the Life" (I read the news today, oh boy!) and reminiscing about other albums from the same period which I think were as "important".



I usually manage to chase it out. A story in the Independent UK, "Worse than Chernobyl: 'dirty timebomb' ticking in a rusting Russian nuclear dump threatens Europe" brought it back.



Published: 10 June 2007

20,000 discarded uranium fuel rods stored in the Arctic Circle are corroding. The possible result? Detonation of a massive radioactive bomb experts say could rival the 1986 disaster. By Rachel Shields




Anyway, I had a silly inspiration: I asked hakia "Is there any way to delay the trouble coming every day?" hakia said unto me:

Good question!
Department of "no way to delay that trouble coming every day" - Update alerts: See this page.



Not a single link of the first fifty suggested that there might be a way; almost all repeated that there is no way.





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Saturday, June 09, 2007

 

French Legislative Election - Round 1 Eve

Tomorrow the French have another opportunity to vote; this time it is for the Assemblée Nationale (legislature).

The rules are similar to those in the presidential election. There can be a winner in the first round with an "absolute majority": over 50% of votes cast and over 25% of possible votes. If not, as many candidates can advance to the second round as receive at least 12.5% of the potential vote (total registered, regardless of turnout). Theoretically, in a very even race with 100 % turn-out, eight candidates with 12.5 % each would all advance (and if the vote were that balanced, the second round would give the same result!), but that just doesn't happen. In the second round, whoever receives the most votes wins, even if that is less than 50%. There can be no more than two rounds.

Another oddity is the election of "suppléants". Whereas the presidential candidates run alone (i.e. there is no vice-president nor are their vice-presidential candidates nor prime minister candidates), the legislative ballots each name candidates for "deputé" and "suppléant". The "suppléant" are sort of "vice-deputies", the official and permanently designated substitutes for deputies who can attend parliamentary sessions and vote in place of the deputies when the deputies send them instead of showing up themselves.

Why would "deputés" need back-up deputies or vice-deputies or whatever one should call them? If they don't expect to serve full-time, why do they run? Another particularity is the "cumul des mandats", which allows elected officials to hold more than one elected office at the same time! (During the presidential campaign, candidates proposed eliminated the "cumul des mandats"--but they all lost). In fact, not only is it allowed (with some limitations on how many offices and of what types simultaneously), it is expected of the current government ministers. Prime minister Fillon has stated that any of his fourteen ministers who is not also elected to (another) office will have to resign. Hence the need to have "back-ups" to do the actual legislating.

While there are basic restrictions on who can run (minimum age, mental and moral competence, citizenship, discharge of national service obligations, e.g.), candidates need not reside in the district in which they seek election. In most cases, having a local base and network is advantageous, of course, but prominent national figures may turn up almost anywhere. For instance Francis Lalanne, a singer (or, as he declared his occupation on his inscription, "poet") who has been visible on TV (and in concert, records, etc.) for years has chosen to run as "independent ecologist movement" candidate in the same district as Yann Wehrling, national spokesman for Les Verts (the Green party).

It is noted time and again that despite all the talk of equality in France,there is a low proportion of women in the legislature compared to other European countries. In the district in which I reside (9e du Bas Rhin), three of the eleven candidates are women. Only one ticket has two women, but I suppose they count deputies, not vice-deputies when they tally the number of women in the legislature.


Candidate Vice-Candidate

Male Female
Male UMP - Presidential majority party
UDF - Mouvement Démocrate
MPF
Front National
MNR-Contre l'Immigration-Islamisation
Lutte Ouvrière

Mouvement ecologist independent
Les Verts
Female Parti Socialiste
La France en Action
Ligue Communiste révolutionnaire


I doubt that a woman will be elected here; Sarkozy won by too large a margin for the Socialist to stand a chance. In fact, Bayrou came in ahead of Royal in the first round in this region, so I suspect the race will be between Loos of the UMP and Kern of the UDF (MoDem).

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Monday, June 04, 2007

 

No comment: Crimson Curriculum





What Were They Thinking? More Than We Knew. - washingtonpost.com

"Dogs are really keen observers of the world around them," said Bruce Blumberg, who teaches classes on dog behavior at Harvard University.







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Friday, June 01, 2007

 

How many ways can one flatten a cube by unfolding?

I'm sorry to not be able to bring you a perfect result. Would you mind trying to rephrase your query?

Well, no I don't think it could be much clearer without becoming much longer and likely more complex. But maybe I should explain why I'm asking, at least in this post if not to Hakia.



Imagine a cube made of lots of little identical cubes: 8, or 27, or some other integer raised to the power 3. For simplicity, let’s call those little cubes “cells” and save “cube” for the big composite one.



Imagine that these cells don’t really have sides, just edges (a lattice framework), so that if you are in one of these cells (floating, or clinging to the frame) you can move into the one below, the one above, or one of the four around the sides...unless, of course,

  • you are at a boundary face of the cube so only five faces (those other than the one corresponding to the boundary face of the cube) lead to other cells;
  • you are at an edge of the cube, with two adjacent faces of your cell at the boundary of the cube, so four faces lead to other cells;
  • you are in a corner of the cube so that only three faces lead to other cells.
In other words, you are like a rook in a three-dimensional chess board (but only planning to move one cell at a time, like a pawn).



To help stay orientated, let's suppose the cells change color in a regular fashion: the higher the redder, greener from left to right, and bluer from back to front (or from "in" to "out"). Looking up, the cell above looks a little redder than the cell currently occupied. To represent the choice of options on a two-dimensional computer screen, how might one unfold, or cut and then unfold, the cube?



Over the past few months, I've found and used three tools for helping choose colors to use on a web page:

  • Sortable Color Name Chart, which as its name indicates, provides a bunch of swatches or tiles of color samples which can be sorted according to various criteria (brightness, hue, etc.). Each tile has black text and white text. However, there are no indications of brightness or color contrast, nor possibility to try other text colors (or even colors other than the 200 or so that is shows).

  • A second, and much more helpful tool, is Gez Lemon's Color Contrast Analyzer. Here, in an interactive page, one can enter color codes for foreground and background and the tool in the page produces a sample with evaluation of luminosity contrast and color contrast. I used this to help improve the contrast, and legibility, of this blog recently: the title banner is now much darker than the original orange, for instance. The site also provides examples, with their contrast evaluations, of a range of foregrounds for a range of backgrounds. Even better, he offers a Firefox extension to automatically audit and report on the contrasts of most elements of any page!
  • Color Scheme Generator 2 proposes sets of colors that "go together" using some color-theoretic algorithms. It provides the user lots of possibilities to choose from: color or colors that provide the basis, and some aspects of contrast. It also provides a color-blindness simulation, so that one who is not color-challenged can get an idea what it would look like to others. Unfortunately, while it does provide this subjective aid, it does not indicate contrast indices nor guarantee that the schemes it produces will meet the Web Content Accessibility Guidelines.


While each serves a purpose, none really enables me to choose pairs of colors I like and which provide enough contrast, although the Color Contrast Analyzer comes pretty close. So, I'm tinkering with a tool that allows one to choose a background color (or perhaps a foreground color), then discover what colors provide sufficient contrast with it (the tool calculates the indices for a range of colors, and only displays samples with those that meet or exceed a threshold) to finally choose a combination one likes.



That is why I am wondering how to represent in 2-D the six adjacent cells one would see while traveling within the RGB cube in my tool's user interface; the color of the currently occupied cell should be represented as well. I have a working prototype, with a layout I find acceptable, but I started wondering about alternatives, and voilà! How many ways can one flatten a cube by unfolding?



Because the faces of a cell are flat, we could simply undo all the seams and show each one as an independent square, arranged in various ways. But this doesn't really help represent the 3-D experience, I don't think. I could be wrong, but I'll only consider cutting the cube into three pairs of sides, two half-cubes of three sides, or a single "bear-skin rug", and not other cuts into unequal numbers of sides. I'm sure I'm not the first to do this, it was probably done by the ancient Greeks, but I don't know where to look it up!

We could suppose that we can look toward two faces at a time by looking toward the seam that joins them. How many ways could we do that? There are twelve edges to a cube, each joining two faces. But how many ways could we take them apart, leaving pairs of adjacent sides joined? Eight:

  • U[pward] can be paired with R[ight], L[eft], O[utward], or I[nward] (but not with D[ownward] because they don’t share an edge to begin). Removing U with its partner undo six seams, leaving six. The six undone are
    • U’s three seams with the three of {R, L, O, I} left behind,
    • its partner’s two with the two adjacent of the three left behind,
    • its partner’s one with D.
  • Once U is paired, three possibilities remain for D, but only two of them work: we only have six seams left (including D-and-partner) we must have three to join three pairs of faces, so we can only undo three, not four. Pairing D with the middle face of the three remaining would undo four, and leave the two “end” faces unjoined. Hence D must choose one of the two “end” faces.
Next, how might we split the cube into two flattened half-cubes of three sides each? There are only four ways of separating the cube into half-cubes in this way: 
  • Starting with U again, it only has four corners, determining its four possible half-cubes.
  • Once a corner with its three faces is removed, the other three meet at the diagonally opposite corner and leave no option.

If we have three faces that share a common corner, we can undo one of the three seams that joins them to flatten them to an “L”. It doesn’t matter which of the three we choose: since each face was joined to the other two, it will still be joined to at least one. So for each of these half-cubes, we have three possible “L”s, preserving two seams. The other half-cube will also preserve two seams. While one could impose a symmetry constraint, so that the choice of seam to undo in one half-cube "matches" the one undone in the other half-cube (its opposite, for instance), that isn’t truly necessary. In general, then, there are three options for each half-cube, nine for the two of them. Thus, we have 36 ways to flatten the cube into pairs of L’s.

And how many ways to skin a cube? I'm not sure yet. To hold the six faces together requires five seams, but not all combinations of five seams will work. For example, consider the set of the four seams which join the four sides plus one of the eight other seams: we'll have a tube with either the top or the bottom attached and the other not! And we have eight ways to do this, and as many for the two equivalent horizontal tubes, eliminating twenty-four cases of the 792 ways of taking five elements from a set of twelve.

An "easy" way is to leave the top and bottom each hinged to a side (not necessarily the same one for both), then undo one of the seams to unroll the tube of sides as a band. Four possibilities for the top-seam, four for the bottom-seam, and four for where to open the "tube": 64 possibilities at least. And the same should be true for each of the two horizontal tubes, I suppose.

For some, but not all of these flattened bands, it is possible to pivot a side sharing a corner with the top (or bottom) to share a seam with it instead of with the band of sides. For example,

T
LIRO
B


if "out" (the front face) were to stay attached to "top" rather than to the band, the "skin" becomes



TO
LIR
B


or (same thing on the other end, instead)



T
IRO
LB


or (doing both)



TO
IR
LB


I'll continue trying to figure this out (or find the answer in some old Greek sand), but not in this post: clearly there are way too many possibilities for any one of them to be "intuitive" or "natural" for my user interface, so I'll probably stick with what I have (which is much like a two-"L" solution with the two facing each other, as if on a circle, with the "current" cell color shown in the middle).

Not to forget...



The first link Hakia provided was pretty interesting: PolyMesh unwrapping and UV mapping  While it is mainly about how to use a polymesh editor to unwrap general surfaces, it does unwrap a cube as a simple example. But it doesn't discuss how many ways there are to do so, it just shows one that works to produce a single flat piece. It also indicates
Mesh unfolding is carried out using the ABF++ (Angle Based Fitting) algorithm as published by SHEFFER, LEVY MOGILNITSKY aand BOGOMYAKOV.
It seems a "polymesh" is what one obtains when one approximates a three-dimensional surface, which may have curvature, by plates (which are flat) joined by seams. The tool behind this article adds "texture" to such a surface; sort of like taking a bear-skin rug, wall-papering it, then re-shaping it into a stuffed bear. It does so only virtually, for 3-d graphic rendering and animation (I think, but I'm not really familiar with this tool).



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