Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
What's the story with these ads on Slashdot? Check out our new blog post to find out. ×

Comment Only correlation shown? (Score 1) 300

I've read through the paper (draft) now, and it seems like they really only show correlation between a group they call Harbingers and "Failure" of products.The group of Harbingers is characterized by purchasing at a discount. soooo,

I would lean more towards a conclusion like: "Stores that experience low sales apparently place products on discount and there is individual price elasticity".

The figure on page 38 shows that "Avg. Profit relative to existing Products in the Category" has a strong bias against "products that flopped" already at *Week1* relative to "Products that survived". That is *right* away, there is a systematic bias that seems constant so if I were to look at data after that I would be *highly* suspicious about directions of causality.

In addition, most of the article is vast amounts of bread-text that seem to support circular reasoning.

Can anyone find a place where they actually come up a direction of causality?

Proving the direction of causality being *from* the "harbingers"-group picking loosers could be supported by

  • 1. Define the set of Harbingers
  • 2. Introduce a number of new products.
  • 2a. in half the shops at fixed prices
  • 2b. in half the shops let the shop set the price
  • 3. Show that the Harbingers from step1 purchase the same relative amount of the products in scenarios 2a and 2b.

Note, Separating the two parts without interference may be hard :)

Comment Links to the actual study? (Score 4, Insightful) 300

An online summary of a newspaper pay-walled newspaper reporting on an article... quoting the original with sentences like "At least, according to a group of researchers ..." and "n a study published in the Journal of Marketing Research, researchers ...". Anyone have an actual link to the actual paper? I have a nagging suspicion that this may actually be an artifact of how the analysis is done.

Comment Adequate security (Score 1) 130

Perhaps the security is adequate if that is the best plan.

Security is not about making absolutely sure, it's about:

1. Lowering likelyhood: Making it reasonably hard to break, so that the bad guys will go somehere else.
2. Spend wisely: Not spending more to defend that the likelyhood of loss times (value lost + value bad guys gain) (in general terms)


a. Round up the likelyhood, the bad guys are better than you at getting ideas.
b. Destroy sensitive and remove generally valuable parts to reduce the bad guys value
c. The value lost is *not* the money spent on the lost property. Perhaps you wasted a small bit of effort making it? pehaps you can recreate new and better cheaper?

I think the value of the space-shuttle is mainly sentimental and image-loss on theft, so you should probably not spend more than a simple escort -- mainly to prevent traffic-problems.

Comment Re:Every 6 months Ubuntu tries to get me to switch (Score 1) 341

Im guessing you have a diNovo edge? Run the following as root:

# fix hiddev to hidraw in BT rules and put it where updates dont overwrite
for x in /lib/udev/rules.d/*-bluetooth-hid2hci.rules;
    do sed -e 's/KERNEL=="hiddev/KERNEL="hidraw/' \
                <"$x" >/etc/udev.d/rules.d/$(basename "$x");
# restart udev
service udev restart

It even work if "they" change the numbering again :) (like from 62 to 97 :)

Comment libstdc++ and the boost project (Score 2) 329

Look at the libstdc++ for GCC and some of the boost project code.

That code has production quality, is written in a style that actually utilizes c++. Beware that c++ recently got quite a few new features that have not gotten too much usage in libstdc++ and boot you may want to read up on that separately.

There is an *excellent* FAQ on most of the fine-grained aspects of c++ at http://www.parashift.com/c++-faq-lite/

In general, stay away from tutorials on the web, they are mostly written by people who have little or no experience and thinks they should teach the world about for loops or whatever because they just made one that doesn't crash themselves.

As a side note: that goes doubly for javascript, a much better search term to find quality code is ecmascript, unfortunatly there is no such good discriminating search-word for c++.

Comment DONT PANIC! (Quantum computer size & crypto) (Score 1) 228


Today, quantum computers are *very* limited in size. The number 15 has been succesfully factored into the primes 3 and 5.

There is no really promising ways to produce large amounts (~1000) qbits. I strongly suspect that the difficulty in generating qbits is (at least) exponential in the amount of qbits to produce.

qbits cannot be composed after they creation (at least with known physics), so I am definatly *not* holding my breath for quantum computers to break RSA-2048 or AES256.

When RSA is broken (when it takes less than a few hundred years on average to find a secret key), we already have multiple other crypto-systems ready. Elliptic versions of RSA are *already* part of standard-implementations in browsers and they shift the amount of qbits required with several orders of magnitude (with known math).

Comment Re:DIY vs. complete dreaming? (Score 1) 903

I believe that teleportation *could* be possible, although it would not be "teleportation" as much as "teleduplication". However, you just need to:

    * A. Create a molecular constructor for the tele-"portation"

    * B. Create a mechanism for "snap-shotting" the state of all atoms in a human body. (rougly a count of 7*10^27)

    * C. use some way of transmitting massive amounts of information FTL.

C is certainly possible, but then known methods have problems. Causality is actually preserved in them so the infomation available when you decide to transmit your information is limited.

Have you ever read anything non-sci-fi about wormholes? It's not like people would fit in -- and especially not like they would come out in any kind of configuration like they went in.

Hyperdrive. It is just a word -- used by sci-fi to suggest FTL-travel. If you had some matter with negative mass, and some means to control/move it you could distort space-time to allow FTL-travel but I'm not holding my breath for either of those requirements.

As for positions "suddenly changing" -- what are you talking about? Bodies that can be said to have postitions don't "suddenly" move. There is not even any evidence of any quantum on time, so -- at least for now -- you should think of all movement as continuous.

Comment DIY vs. complete dreaming? (Score 1) 903

Time Travel: Not with a detectable effect, and certainly not for anything human-sized. The arrow of time may be relative but it's certainly not reversible on a macro-scale.

Faster than Light Travel: How would that occur? *Every* experiment shows that FLT would require infinite energy for classical bodies. For sizes where quantum-theory apply it's more complicated but doesn't concern physical presence. If you had a programmable molecular-replicator maybe :)

Human-level AI: Well, possibly... but only by dumb-luck. Which is weird since "human-level" is really not that high.

Discovery of Aliens: Well, that is mostly random.

Immortality: Naaaah..... not really likely to work on complicated systems like a human body. Not for "eternity" anyway -- maybe for long but not forever... and not as in "cannot be killed".

World Peace: How would that come about? only if there was nothing to fight for -- meaning total extinction.

Nah, fetch me some duct-tape, a laser and a shark and i'll show you what comes first.

Comment To each as deserved (Score 1) 232

Perhaps people do not appreciate what their sysadmins do because the sysadmin is not helping but hindering them?

My best experience ever with sysadmins was at DAIMI (now Department of Computer Science) at the University of Aarhus, Denmark. Perhaps you can compare what you do to them?

They ran by the priciple of freedom under responsibility (traced, of couser :) The system was not down for any annoying period of time while I was there. Sysadmins were:

  • Incredibly service-minded,
  • Running stuf was allow-by-default, of course this was UNIX, so you could mostly trash your own stuff :)
  • Active logging of who spawned what and used how much CPU/disk/net, and an email asking why when you were outside the norm
  • Limited disk-quatas, but you could simply extend your own quota by running a command and giving a reason, the space was immediatly awarded to you for use -- if the reason was not good enough they would email you
  • Allowed most anything as long as it didn't interfere with the other peoples ability to use the system.

Why the RIAA Really Hates Downloads 289

wtansill recommends the saga of Jeff Price, who traveled from successful small record label owner to successful Internet-era music distributor. His piece describes clearly what the major record labels used to be good for and why they are now good for nothing but getting in the way. "Allowing all music creators 'in' is both exciting and frightening. Some argue that we need subjective gatekeepers as filters. No matter which way you feel about it, there are a few indisputable facts -- control has been taken away from the 'four major labels' and the traditional media outlets. We, the 'masses,' now have access to create, distribute, discover, promote, share and listen to any music. Hopefully access to all of this new music will inspire us, make us think and open doors and minds to new experiences we choose, not what a corporation or media outlet decides we should want."

OOXML Will Pass Amid Massive Irregularities 329

Tokimasa notes a CNet blog predicting that OOXML will make the cut. Updegrove agrees, as does the OpenMalasia blog. Reports of irregularities continue to surface, such as this one from Norway — "The meeting: 27 people in the room, 4 of which were administrative staff from Standard Norge. The outcome: Of the 24 members attending, 19 disapproved, 5 approved. The result: The administrative staff decided that Norway wants to approve OOXML as an ISO standard." Groklaw adds reportage of odd processes in Germany and Croatia.

We declare the names of all variables and functions. Yet the Tao has no type specifier.