Slashdot Mirror

Charles Proteus Steinmetz(read the last item on the page 1st) took on old theoretical idea of complex numbers (real + imaginary)
a + bi
and turned it into a way to quantify impedences in alternating current circuits
Z = R + jX

gewg_

The competition however involves your facing an unknown strategy. What they did was construct a profile of strategies which reach a high payoff, and tweak it to allow them to identify each other. The profile of strategies is not even Nash; they did not prove anything, they just fooled the evaluation method.

Sidenote: notes on the repeated PD.
1) If the game lasts one single step, whatever your opponent does it is always better for you to defect. So you defect and so does your opponent.
2) If the game lasts 10542 steps, you know that at the 10542-th step you and your opponent will both defect. So there is no point in cooperating at stage 10541, so you also both defect. And so on. Thus the only sustainable combination of strategies (= Nash) is to defect from day one.
3) If the game has unknown length or is infinite, then cooperating becomes sustainable. Actually any payoff in the convex hull is a Nash payoff.
This is with perfectly rational players; real world players are not however.

Now have finite state automata play the repeated prisoner's dilemma, and define their "size" as their number of states. A finite state automaton of size n can not "count" up to n+1; then even in the finitely repeated PD, if its length is bigger than both lengthes then cooperation becomes sustainable. The actual result (due to A. Neyman http://ratio.huji.ac.il/dp/dp69.pdf, Th1 p9) is that as soon as _one_ of both players is approximately not larger than the exponential of the length of the game, then any payoff in the convex hull of rational payoffs can be approximated.

Similar tight results for push-back automata or Turing machines of bounded Kolmogorov complexity are unknown yet.

The interesting question is to design a Nash pair of strategies which reach the highest payoff but do so with a limited number of allowed lines of code (= Kolmogorov complexity). This is definetely no trivial problem: even if I claim to always cooperate, once I know that my opponent is dumb it may be easy (?) for me to pretend to cooperate but later betray him nonetheless ...

That's not correct. From http://www.snopes.com/science/stats/unemploy.htm Although this belief is widespread and has at times been reported as factual in the mainstream media, the truth of the matter is that unemployment statistics are gathered through a process of sampling a representative number of households; they are not arrived by counting the number of unemployment insurance claims made during a particular month. Data collected in the Current Population Survey (CPS), a monthly survey of over 60,000 households, is used for this purpose. From this data, an extrapolation is made about the unemployment status of the country as a whole.

See, the text you just posted says NOTHING to contradict what you were trying to contradict. So I choose to pick 60,000 households to get my number from, big deal. I can STILL fuck with the numbers By counting the people in those house as not unemployed, even though they don't have jobs.

The reality of the situation is that the Bush admistration has redfined what constitutes "unemployed".

The text you posted is nothing but a bait-and-switch argument. Snopes doesn't give you enough information to actually show that the claim they're refuting is false, nor does the page the're linking
It's like me saying, "Look a Corvette!"
And you responding, "No, it's blue."
And then a third party coming along based upon only hearing the conversation and note actually seeing the car, claiming it most definately not a Corvette. The reality is that there has been no information presented to you that proves it's not a Corvette.

Additionally, do NOT trust snopes as a sole source for information.
For example, this article is flat out worng:
link

I have emailed them with multiple refences which seem to support that Charles Proteus Steinmetz, did indeed perform the feat in question.
(Not just web links, one of these is a historical sidenote from an advanced math book I used at Cornell.)
Nonetheless, the snopes article was not changed at all. I dodn't think that particular article is a huge deal or anything, but the lack of change to the pages or even a reply to my email, makes seriously doubt the intellectual rigor of any "investigation" they do.

Well, firstly: there are a lot of stupid inventions (e.g.: hat that spreads into an umbrella).
Secondly: there are a lot of inventions that are developed based on previous ideas and are fully exploited (e.g.: paperclips - there are many designs, quite a few still being used).
Thirdly: many inventions are innovative, but just not quite good enough to use (e.g.: the development of the zipper took several tries).
Fourthly: The technology is often not good/economical enough in practice (e.g. Lilienfeld's invention of the field effect transistor in 1925 (patented in 1930).
Finally: some inventions are so far advanced for the time that no one (other than the inventor) sees any realistic use for it (e.g. Babbage's analytical engine)

Can someone with clue explain to us lay-people how what the article describes is different from what this kid did 'in a couple of late nights'? His software scans the record in using a standard flatbed scanner. Is the new version being goverment funded supposed to able to 'rip' at a better quality, or what exactly is the deal with the government funding on this?

http://www.cs.huji.ac.il/~springer/

This reminds me of this project (which has been Slashdotted before) which can be done with a home scanner. But this new Berkeley method is obviously much more advanced.

I am now working on an OSS project with a lot of these ideas in mind.

Discourse District
A dynamic repository for community writings, a mirror, mapping the writing community.

(the link above points to an abstract, the link to the system is at the bottom)

basically it is a wiki adaptation with touchgraph interface, that is meant to be a community utilized concept map.
Born out of a need to define the Complexity community, its scope, and the fact that no one person could define it , since everybody else would disagree.
This way the community would be defined by anyone adding their activities, and a graphical map would be a new form of definition

That number again '0'(Chief Wiggham)

I am new to this and would appreciate your comments on
1. Concepts
2. UI
3. publication
4. that stupid IE6 SP0 bug on calling an applet from the contatining page and getting the width...

I am now working on an OSS project with a lot of these ideas in mind.

Discourse District
A dynamic repository for community writings, a mirror, mapping the writing community.

(the link above points to an abstract, the link to the system is at the bottom)

basically it is a wiki adaptation with touchgraph interface, that is meant to be a community utilized concept map.
Born out of a need to define the Complexity community, its scope, and the fact that no one person could define it , since everybody else would disagree.
This way the community would be defined by anyone adding their activities, and a graphical map would be a new form of definition

That number again '0'(Chief Wiggham)

I am new to this and would appreciate your comments on
1. Concepts
2. UI
3. publication
4. that stupid IE6 SP0 bug on calling an applet from the contatining page and getting the width...

Here's a better link.

What's strange about this particular story, is the snopes.com article on it.

A number of reputable sources, who have obviously researched Steinmetz, seem to confirm this story as true, yet snopes does not. Perhaps snopes is wrong for once?

IHMO, available cycles should not be sacrificed to the overhead this will introduce when the problem is sloppy programming, whether it is programmer or retarded-i-can't-plan-manager induced.

By the way, anyone caught using try-catch-finally clauses for 'liberal' conditioning need be hung by way of testicles or fallopian tubes.

The whole basis of the GPS cell phone data is in the interest of public safety. To assist you when you need it most.

While I agree with most of your post, I have to disagree with this line. That is the promoted use of it, and is quite a good use. However, there's a not-so-well hidden agenda of advertising. When I got my new phone, Verizon was specifically saying that they have plans to use the system to provide "location-based services". That is, based on your location they will send advertisements and instant coupons for nearby businesses.

"John Anderton, you could use a Guinness right now."

Emergency services are also provided, as a way to convince people we need this. You want to be safe don't you? Fortunately, my phone (and many other models, I'm sure) give me the option to transmit the aGPS data with every call or just with calls to 911. This is something I can live with. The service is there when I have a real emergency, but (unless the phone is lying to me) that information isn't available to advertisers.

Someone in another thread said that the location system doesn't really use GPS. That's not quite true. The cellphone "Assisted GPS" service does use the GPS satellite system, but doesn't need a full GPS receiver in the phone itself. It also uses data from the tower. The IEEE magazine "Computer" had a good summary of the technology. A PDF of the article is at http://www.cs.huji.ac.il/~postPC/docs/Geolocation_ assistedGPS.pdf

According to well-known economists Josh Lerner and Jean Tirole, in an article recently published in the Journal of Industrial Economics, open-source software development needs to overcome a number of difficult problems before wide-scale adoption of open-source solutions in industry and government becomes feasible. Two of the more serious problems with open-source software are the "forking" of open-source projects and the orientation of open-source products towards high-end users.

He then proceeds to define "forking" in this context:

The forking of open-source projects occurs when passionate disputes between open-source software developers over product design lead to the splintering of projects into a multitude of varieties. With proprietary software, forking generally does not take place since development is centralized within a firm and disciplined by market forces. Relying on a current open-source product design is, therefore, inherently risky.

So it seems that he is referring more to project splitting than forking.
The paper in question, The Scope of Open Source Licensing states:

Forking refers to an internal threat of competing groups moving in different directions and producing incompatible versions of the same initial open source project. It is unclear to us how license type will affect the probability of forking or the effectiveness of the original project leader's response; this topic may reward future research.

Which is, IMHO, a valid concern, although not a major one since it occurs very infrequently.
Or possibly, you would like to argue that Josh Lerner and Jean Tirole are also "idiots who don't know what they are talking about"?

Regardless, the "forking" issue is not the major one.

Sauer's article addresses the possibility of Israel's Ministry of Finance abandoning the currently used commercial software in favor of open-source alternatives and their argument that the move will save Israeli taxpayers up to 60% of the cost of continuing to do business with Microsoft and other proprietary software companies.

Sauer says that

There is a common misconception that open-source software, such as Linux, is cost-effective because it can be freely loaded on as many computers as desired without incurring additional license fees. In fact, software license fees comprise only a small percentage of the total cost of ownership (TCO) of software. Most estimates place software acquisition costs between 5% and 8% of TCO. TCO is dominated by costs related to customizing systems, maintaining and servicing systems, and training systems personnel.

He then continues to point the real problem:

The article in question is Open question. The government claims open-source software means a 60% saving. It doesn't add up. Dr. Robert M. Sauer has a homepage if you are interested in finding out more about his other work.

Obviously, they'll use a scanner.

Speaking of scanners and science. Remember this guy (as mentioned here)? We actually did something similar. 2400 dpi is enough for 78 rpm records, and you can get sound from vinyl. Of course, it's noisy, but you can still hear what the song is like.

Scanners have real world applications! :-)

/* story Ripping Vinyl Via Your Scanner?

Actual site http://www.cs.huji.ac.il/~springer/

Workshop In Computer Construction - From Nand to Tetris

I personnally enjoyed the way this guy rips vinyls: by scanning them !

here, and the author has updated his site and made an apology...start checkin'! :)

Open Mouth, Insert Foot.

NOW he has released his source.

He is taking the average of amplituth of a x-y value he calculated (white = high(255), black is low value(0)). This is not the perfect method of decoding it, But it add's anonther factor 256. It is not black and width images,

this and the 60 Db factor makes it more feasable.

In response to doubtful Slashdotter's, it looks like the author has posted his code. It really is sucky. Only two comments in the whole program.

The guy goes on to say;

Woke up, fell out of bed... rampaged by a slashdot horde.

Some clarifications to the slashdot crowd:

I am sorry so many of you thought this page was a hoax only because no source code was supplied (I'm sure you'll all agree, now that you can see the code, that it is both straightforward and crappy).

Here it is. The guy has also posted an update here with a little more detail ....

Here it is. The guy has also posted an update here with a little more detail ....

But look at the really convincing drawings he made, while in the development phase of his record scanning software. They're highly scientifical.

Yup

Also, "jeremiah" is an awfully odd name for someone nowadays

The prophet Jeremiah was active in Jerusalem during the tragic period of the city's destruction by the Babylonians, which occurred over several stages... Jeremiah prophesied an ineluctable, unavertible disaster... Jeremiah castigated the people bitterly for forsaking God and the Torah and turning to idolatry. With a sense of the inevitability of a terrible punishment, he felt disgusted with his life. Gradually he became the leading exponent of the approach which called for surrender to Babylonian might and not attempting a rebellion against its awesome strength under the auspices of Egypt... Although Jeremiah was saliently a prophet of apocalypse, he emphasized the temporary nature of the destruction and the consolation to be found in the certainty of the nation's return to its land. (emphasis added)

Sir Humphrey Davy,
Abominated gravy,
He lived in the odium,
Of having discovered Sodium
-- Edmund Clerihew Bentley

I've run into this problem in the past as well. My solution was to abandon Bourne shell as a scripting shell and use ksh instead. To be 100% portable, you should use Bourne, but most of your major *NIXes have support for ksh (including linux, Solaris and AIX..not sure about HP-UX) and it has a lot of nice scripting gizmos like associative arrays, printf command, co-processes, pattern matching, etc. Of course, maybe you don't need all of that stuff.

As an aside, there has been a lot of extensive research on making portable shell scripts. Bruce Blinn's book Portable Shell Programming: An Extensive Collection of Bourne Shell Examples is a good resource that might help as well as GNU Autotools documentation, which is the definitive guide on this sort of thing. Another useful jumping off point that has some good materials and a lot of useful links is Shell Script Porting Guidelines

• Without loss of generality lets talk about news sites. They won't do it because it requires an amazingly massive migration of nearly all of them together. Otherwise they will loose most of their readers in a blink of an eye. The readers will just prefer those that haven't commercialized like that.
• This won't happen so fast technologically. I've made a pretty extensive research at HUJI regarding online / offline micropayments. The bottom line is that due to its nature, monetary transactions are too expensive to allow to sell things less than roughly one dollar. The transaction will cost more than the goods.

I want a cluster of Palomino'ed 420's running Mosix scalable linux clustering (see http://www.mosix.cs.huji.ac.il/) to do my meteorology/air quality forecasts (see http://envpro.ncsc.org/projects/SECMEP/secmep.html with.

It depends upon how you define freedom. If freedom means never having to ask the author for permission, then no, the GPL is not free.

I don't define freedom as never having to ask the author for permission. I define freedom as being free to distribute, modify, use, study, or enhance my information.

Freedom doesn't mean you can do everything you wish to do, without any limitations. Freedom needs to have reasonable limitations. Like free countries restricting the citizen's freedom to murder others, in order to preserve others' freedom - if you're murdering, you're taking someone else's freedoms away. So therefore here your freedom is restricted.

But according to the rules of the GPL, a license freer than the GPL is just as bad as one that is more restrictive.

No. But a licenses less restrictive than the GPL, might in longer terms lead to derivatives with licenses more restrictive than the GPL.

But a question: If the GPL is free despite its restrictions, since the end developers agrees to those restrictions, then why aren't proprietary licenses free as well? Don't users of VC++ also voluntarily give up their freedoms when they agree not to distribute code linked to the MFC libraries? Oh...wait...you're allowed to distribute...without restriction your code developed using VC++ and MFC... Damn. I'll have to think of another analogy.

No, in fact, Microsoft's newer licenses for some of their .NET development products, actually forbit you from writing free yet copylefted software with them. Not because of incompatibility with the copyleft, but it just states in the licenses that you may not write copylefted software with those products...

Anyway, for what it might interest, I recently (a month or more ago) wrote an "article" with my opinion on the GPL vs. BSD license wars - http://www.cs.huji.ac.il/~alsbergt/freedom/gplbsd. html.

was EVEN distribution. Did anyone else notice that this one machine seems to be working harder than the others?

So far MOSIX was developed 7 times, for different versions of UNIX and architectures. It has been used as a production system for many years. The first PC version was developed for BSD/OS. The latest version is for Linux on X86/Pentium/AMD platforms.

Yes, they did start out basing their system on proprietary kernels, then they moved to BSD, then to Linux. The current work is not about the basic idea anymore, moving processes around somehow, but about things like distributed virtual memory, distributed file systems, and migration strategies.

This isn't "playing catch-up", it is cutting edge research by the people who did the original work moving to the BSD and Linux platforms because they are more widely available, are better supported, are easier to license and share, and have more software available for them.

• Mozilla with some Hebrew extensions.
• Somethinng from the IGLU FAQ, with links on places to find Hebrew fonts and keyboard support.
• Some common Linux applications with Hebrew support.

I'm not defending Wagner so much as I am defending scholarship. It is fine to produce a monograph which seeks to prove that Wagner's every motivation was based on antisemitism, and only cites other sources which back up this claim, ignoring a great deal of other Wagner scholarship, but it is foolish to read this monograph and no differing viewpoints.

BTW, to see why you shouldn't hyphenate "antisemitism", click here. According to that page (with which I am inclined to agree), hyphenating "antisemitism" basically means that you think "Semitic" is meaningful, and that defamation of Jews is based on "their race," which is a worrisome (at best) stance to take.


~wog

Apparently DIPC (Distributed IPC) can run with MOSIX, although DIPC a few months ago did not optimize migrated processes. It could work, but works better when DIPC realizes that processes are able to run on other systems.

It has been calculated that the normal human is host to about 10^12 bacteria on the skin, 10^10 in the mouth, and 10^14 in the gastrointestinal tract. The latter number is far in excess of the number of eukaryotic cells in all organs which comprise the human body.

• Mach was the "granddaddy" of distributed OS work, with most of the recent efforts going into GNU Hurd.
• There's Mosix that builds a NOW atop Linux
• The MIT Parallel and Distributed OS Group should be mentioned; efforts include the Exokernel
• Plan 9 has an interesting model for splitting work across "compute servers" and "file servers" and "display servers."
• Distributed Operating Systems lists lots of them...
• Sun's Spring was the basis for much of what is in CORBA;
• Sprite provided a Unix-like distributed OS that provided much of what is being used now to build journalling filesystems
• Amoeba was Tanembaum's successor to Minix; note that Python was one of the side-effects of the Amoeba project...

Each has some somewhat different insights to bring to the table; there is no unambiguous way of saying "this is all vastly superior."

There's a huge list of various operating system projects here: http://www.cs.arizona.edu/peo ple/bridges/os/full.html.
I find all the "pure" distributed OS stuff (systems build from the ground up to do distributed processing and not much else)relatively uninteresting on its own, but a lot of good ideas from those projects can filter into general purpose operating systems, especially when you start talking about clustering or even NUMA. You might want to see MOSIX for a cool, distributed/clusterd Linux version.
--JRZ

MOSIX is a software package that enhance the Linux kernel with cluster computing capabilities. The enhanced kernel allows any size cluster of X86/Pentium based workstations and servers to work cooperatively as if part of a single system.

To run in a MOSIX cluster, there is no need to modify applications or to link with any library, or even to assign processes to different nodes. MOSIX does it automatically and transparently, like an execution in an SMP - just "fork and forget". For example, you can create many processes in your (login) node and let MOSIX assign these processes to other nodes. If you type "ps", then you will see all your processes, as if they run in your node.

The core of MOSIX are adaptive resource management algorithms that monitor and respond (on-line) to uneven work distribution among the nodes in order to improve the overall performance of all the processes. These algorithms use preemptive process migration to assign and reassign the processes among the nodes, to continuously take advantage of the best available resources. The MOSIX algorithms are geared for maximal performance, overhead-free scalability and ease-of-use.

Because MOSIX is implemented in the Linux kernel, its operations are completely transparent to the applications. It can be used to define different cluster types, even a cluster with different machine or LAN speeds, like our 100 processors cluster:

MOSIX is a software package that enhance the Linux kernel with cluster computing capabilities. The enhanced kernel allows any size cluster of X86/Pentium based workstations and servers to work cooperatively as if part of a single system.

To run in a MOSIX cluster, there is no need to modify applications or to link with any library, or even to assign processes to different nodes. MOSIX does it automatically and transparently, like an execution in an SMP - just "fork and forget". For example, you can create many processes in your (login) node and let MOSIX assign these processes to other nodes. If you type "ps", then you will see all your processes, as if they run in your node.

The core of MOSIX are adaptive resource management algorithms that monitor and respond (on-line) to uneven work distribution among the nodes in order to improve the overall performance of all the processes. These algorithms use preemptive process migration to assign and reassign the processes among the nodes, to continuously take advantage of the best available resources. The MOSIX algorithms are geared for maximal performance, overhead-free scalability and ease-of-use.

Because MOSIX is implemented in the Linux kernel, its operations are completely transparent to the applications. It can be used to define different cluster types, even a cluster with different machine or LAN speeds, like our 100 processors cluster:

Since they weren't mentioned, I thought I'd mention them here: Mosix, Beowulf, and I couldn't find SCI.

An NT Cluster is used in an Enterprise to provide broad robust support to many different users who see it all as a single machine.

Doofus. Much of the Torah was actually written in Aramaic. The rest was likely translated into Aramaic at some point then turned back into Hebrew. Every currently available version of the Bible is a translation. Here's a link.

Double Doofus. You support a bogus claim and don't even provide a source. Here's an excellent anti-Code site: http://www.ma.huji.ac.il/~drorbn/Codes/

Of course, this has nothing to do with this Quantum Computation story, except that it's vaguely related to Israel, and it's a crock too. QC is thankfully a ways off yet. But yes, if it works, QC could crack a key of arbitrary length in microseconds.

If they used a UNIX/Linux cluster, more likely, they might well have used a Mosix cluster, which was designed in Israel, originally for PDP-11 UNIX, is superior to Beowulf, and has been in use for over a decade.

If you're using parallel programs, Beowulf is nice. But for ordinary use, MOSIX is better because it will distribute processes across systems automatically. So you just set up your piped scripts or parallel make the usual way.

As for multiprocessor hardware, Linux works just fine for me. I'm writing this on a dual P3, and my other workstation is a dual PPro. I haven't tried it on boxes with > 2 processors though. For a web server, more processors are unlikely to get you any benefit, however. I'm pretty sure that apache on a single processor will easily saturate your network bandwidth, no matter what it is. Now if you're doing really complex CGI's, like, for example, some kind of real-time stock calculations, that require a lot of processing, then multiple processors might help. But if this is the case, I'd probably advocate hooking up several boxes in parallel (Mosix is designed for this) and farming your CGI's out to idle processors on separate machines. Your Database might also benefit from multiple processors, but (for a properly indexed DB) probably only in extremely liminal cases (very, very large DB's), and if so, you should have it on a separate machine too. In general, spend the extra money on RAM instead of another processor. Your clients will thank you :-)

That would be *way* cool. I mean if I could just turn on additional computers and share the processor power on all those computers on my network.

I mean, is something like this allready in the works for Linux?

Check out MOSIX (in particular, MO6): http://www.cs.huji.ac.il/mosix/