That list is woefully incomplete. The complete list for the FAA only: (http://www.faa.gov/data_research/accident_incident) has more than twice the number of incidents as listed on wikipedia for the world.
No aerodynamic control surfaces. That's also why the HyperX cost more. The NASA tests were 10 seconds of scramjet testing and 10 minutes of hypersonic manouvering.
I happen to know that the budget for the first two tests was one million australian dollars each. Of this, the price of the rocket was about half. The Qinetiq engine was built in 2001, and cost about the same as the Australian engines
I think its not the mode of editing that gets readers up in arms. It's that in mainstream media, the job which is done by a slashdot "editor" is split between two people:
1. Journalist. This person looks at thousands of potential stories and fights between all of the ways in which one story can be written. They're most interested in delivering interesting product as quickly as possible and making their own name.
2. Editor. This person looks at one version of each story, and makes decisions about only a few versions of the final format. They care about ethics, reputation of the firm, and story selection for balance over an extended time.
As far as I can see, a lot of slashdot's problems come from having no editor.
Every time I see an "editor" complain that there's no way to avoid dupes because they look at a hundred versions of the same story, I think that slashdot needs an editor.
Every time I see an "editor" complain that spelling and grammar checking should come second to getting stories out there, I think slashdot needs an editor.
Every time I see an "editor" explain that posting an ethically dubiously connected or astroturfing story was ok so that the story gets out there, I think slashdot needs an editor.
Slashdot needs to grow up. Even though it started as Rob's blog, it's been years since the majority of users would accept that quality. "Daddy pants" is not a QA method for adults, and there is easily a hundred years of experience in the media industry about how not to make the kind of errors which slashdot regularly makes.
Actually scramjets do use flameholders, they just don't look like the flameholders from subsonic aircraft. At the most basic level, a flameholder is just a local hotspot with some fuel, which seeds the main flow with radicals to encourage and stabilise the combustion. Cavities, crossing shocks and backward facing steps are all used as flameholders in scramjets.
The speed of sound (Mach number) is a similarity parameter. Other examples of similarity parameters are: Reynolds number, Stanton number and CFL number. Objects have similar aerodynamics at the same Mach number, rather than the same velocity, so that is used as a comparison.
The speed of sound is (to first order) only a function of temperature. Reduced temperature means that the speed of sound is slower. Scramjet engines are tested between 20km and 50km altitude, where there is definitely an atmosphere. It can get very cold there though, so the speed of sound is much lower than at sea level.
Yes, but if "james brown is great" is changed to "john brown is great" sometime in the last 200 edits, how do I find the author? Not only that, how do I have any indication as to why it was changed? Was the fact verified wrong, changed out of spite or just a typographical error. None of these are fatal to wikipedia, but every small question as to whether the current version (and that's all that matters) is reliable is another nail in the coffin.
I would truly like to see wikipedia succeed, but I don't see that happening without an editorial system like that used at other encyclopaedias.
A lot of the articles that are "so short as to be scarecely worth the name" are on topics that would never have been covered by a traditional encyclopedia. Such "stub" articles probably shouldn't be counted in an evaluation of Wikipedia's merit unless they are of a topic that definitely should be included in any encyclopedia.
Where wikipedia says: There are 906538 total pages in the database. This includes "talk" pages, pages about Wikipedia, minimal "stub" pages, redirects, and others that probably don't qualify as articles. Excluding those, there are 352875 pages that are probably legitimate articles. There have been a total of 6752529 page edits since the software was upgraded (July 20, 2002). That comes to 7.45 average edits per page.
So wiki considers stubs, talks and redirects as articles. Which rather makes my point. In addition, there seems to be an average of between 10 and 30 edits to the legitimate articles. Is that even enough to get the broad facts right?
My point is that thousands of people make vague, unsubstantiated statements on wikipedia every day. That's not the same as hard facts, and its not valuable. I'm not saying that no article on wiki is a good as a traditional encyclopaedia, just that the vast majority currently are not, which is rather the point.
So what you're saying is that wikipedia is good because it has the potential to be good some time in the future? I think that wikipedia does have its strengths, but the current version of wiki is not that version, so there's not much point in arguing the greatness of wiki is in its system, when what that system has currently produced is a large number of articles which are so short as to be scarcely worth the name, a large number of articles which include partially/wholly untrue sections and a small number of really great articles.
My gut feeling is that the split is about 50/40/10, but perhaps you have better information. Until the wikipedia consists largely of verified information, its value remains greatly diminished.
Traditional works have several advantages over wiki works.
1. Versioning: If I say I got something from the 1975 Encyclopaedia Brittanica, you can go and check that I got my reference right. Then you can check if the fact was right in that version. With wiki, if I say I got it from the 20.2.2002 wiki, simply finding out if I got the quote right can be a problem.
2. Continuity: Most books fix errors as the version number increases. There is no gaurantee of continuity in the wiki system.
3. Editorship: Most other sources have clear lines about which author is responsible for a whole article, and one person who is responsible for seeing that facts are preserved and false statements are reviewed. There is no clear line of responsibility in a wiki article.
These three things make wikipedia less reliable than other media (but no less reliable than any other website)
I realise this is a bit offtopic, bit I moderated in the discussion on word frequency before I saw your post:
I have to learn German. I need the 86,000 most-commonly used German words. This would give me a nice target of words to get to know in the process of learning it...
And since I'm also an English speaker in Germany I thought I'd note that typing "word"+"rank"+"german" into google returns plenty of sites including: http://german.about.com/library/blwfreq01.htm which only has the top 1000, but that's not a bad start.
In all honesty, I find that the word frequency depends a lot on your environment. Are you speaking in a pub with a bunch of welders or are you reading scientific literature? You'd be much better off just keeping a little notebook and writing down words you see more than once.
I also find that leo http://dict.leo.org/ is pretty good for a lot of stuff that doesn't make it into standard dictionaries.
I'm also a graduate student in physics, and I couldn't disagree with you more. Newtonian dynamics is great for the really simple problems, and these days anything more complex simply isn't going to be done analytically unless you want something specific enough that you can afford to teach yourself Hamiltonian mechanics.
I study in Goettingen (I'm sure you know where that is.) and the mathematics department has a large hall of models of surfaces of least action, mainly done between 1900 and 1950. After the advent of computing most of the problems they were working on were done computationally.
I would just comment further that Newtonian mechanics has the enormous advantage of working mainly in directly measurable values, making errors easier to identify. In fact if you go into engineering, there's almost no system of calculation which doesn't work in directly measureable values, and so I think it simply makes sense to teach simple physics in those terms too.
It exists, and it's called an acousto-optic modulator. a lot of old fax machines used to use them to steer a laser onto the heat-sensitive paper. don't know what they use now though.
I bet if people from the 1920's see the world today, they would be alarmed by the technology and hitech gadgets
Yeah, but would the people of 1994 be so astonished? I don't think so. What are we predicting for 10 years down the track? I'd bet that usable voice recognition technology, universal high-speed wireless and the first non-crap all-electric car won't make your eyes pop out, but they're a lot more likely than a brainwave monitor alarm clock.
Yes, but author-pays sucks for a lot of different reasons. The main one is what happens when a journal rejects an article _after_ the review process (when the costs have already been incurred). Who pays then?
Does the author of an accepted article pay for the reviewing costs if a Journal is crapflooded, or is the payment made before review? In addition, how do you tell the difference between author-pays and vanity publishing? I'd just note that there are very few author-pays journals in the physical sciences.
Yes, but the articles in the journals _are_ freely available, just not available for free. In many cases the articles are even available for less than the cost of a journal subscription: Just write to the author of the article you want, and I'm sure they'll be happy to provide you with a copy.
The question is whether, in addition to being freely available, whether the researchers should have to pay (for example) for web space to publish their articles. The further question is whether the raw data is also public property....
I appreciate some of your point, but could you explain how yould your problem have been solved by free journals? It seems like your problem was more a function of the inconvenience of pre-digital publishing than the prohibitive cost of the journals.
The employees of journals are paid by a private company. If the government wants to have the results of journals freely available, they can nationalize the company, or start their own journals. Requiring a company to provide its product for free is unsustainable (and possibly even unfair, no matter what you think of the scientific publishing system.
That's silly. That's like saying that because software can be copied at small cost, that it must be. To extend your metaphor: the way that the journals see it is that they've taken your method and written a program. Now you want the program for free, because you developed the method. See the point?
But the citizens already _do_ have free access to the information from the research. Internal reports, conference papers and often original data can be obtained if you ask the original researcher.
The point is: 1. Preparing a manuscript isn't free. 2. Publishing (even on the web) isn't free. 3. The journal owns the rights only to that particular compilation of the data, not to the data itself.
For instance the ESA requires all contracts to return a report which is then made publicly available.
Try searching the NASA server: http://techreports.larc.nasa.gov/ if you can't get the Government-funded NASA paper you want.
Try this: 1) Make copy of original. 2) Build back areas which have been eroded with material of choice (clay/plaster). 3) Make copy of repaired carving.
Didn't you ever tidy up a cut and paste job using a photocopier?
And you can calculate the extra energy that spaceshipone would have to expend to get to that orbit, as opposed to an altitude of 100km with no sidewards movement. It's 62 times the energy. So LEO is still a few stepa away.
I realise that this is a bit redundant, but I read the slashdot artile linked to, and what to I see but:
Re:Fixed in new firmware, available here: (Score:3, Informative) by Chucky B. Bear (785810) on Saturday June 05, @03:10PM (#9345433) I've just upgraded to the latest firmware. It is NOT FIXED!!!! They have simply gone and changed the username and password to something else. There is STILL a default superuser account with password.
(You can find it yourselve by just taking similiar steps as in the securityfoces article.)
Maybe reading slashdot sometimes would be a good idea.
Slashdot Mirror
That list is woefully incomplete. The complete list for the FAA only: (http://www.faa.gov/data_research/accident_incident) has more than twice the number of incidents as listed on wikipedia for the world.
No aerodynamic control surfaces. That's also why the HyperX cost more. The NASA tests were 10 seconds of scramjet testing and 10 minutes of hypersonic manouvering.
I happen to know that the budget for the first two tests was one million australian dollars each. Of this, the price of the rocket was about half. The Qinetiq engine was built in 2001, and cost about the same as the Australian engines
I think its not the mode of editing that gets readers up in arms. It's that in mainstream media, the job which is done by a slashdot "editor" is split between two people:
1. Journalist. This person looks at thousands of potential stories and fights between all of the ways in which one story can be written. They're most interested in delivering interesting product as quickly as possible and making their own name.
2. Editor. This person looks at one version of each story, and makes decisions about only a few versions of the final format. They care about ethics, reputation of the firm, and story selection for balance over an extended time.
As far as I can see, a lot of slashdot's problems come from having no editor.
Every time I see an "editor" complain that there's no way to avoid dupes because they look at a hundred versions of the same story, I think that slashdot needs an editor.
Every time I see an "editor" complain that spelling and grammar checking should come second to getting stories out there, I think slashdot needs an editor.
Every time I see an "editor" explain that posting an ethically dubiously connected or astroturfing story was ok so that the story gets out there, I think slashdot needs an editor.
Slashdot needs to grow up. Even though it started as Rob's blog, it's been years since the majority of users would accept that quality. "Daddy pants" is not a QA method for adults, and there is easily a hundred years of experience in the media industry about how not to make the kind of errors which slashdot regularly makes.
"Around here, in a medium-sized city, a typical lot that's not downtown is 20 m^2."
That's a square 15 feet per side, or a small living room. Methinks you don't know how to convert imperial to metric.
AIAA 93-2329
J. Prop. Power V4 N4 1993, p502
Shock Waves (DOI) 10.1007/s00193-002-0147-0
J. Spacecraft V17 N5 1980 p416-424
Amongst many, many, others. Just the sreestream has to be supersonic. After all the BL is always going to be subsonic, no matter what you do.
Actually scramjets do use flameholders, they just don't look like the flameholders from subsonic aircraft. At the most basic level, a flameholder is just a local hotspot with some fuel, which seeds the main flow with radicals to encourage and stabilise the combustion. Cavities, crossing shocks and backward facing steps are all used as flameholders in scramjets.
The speed of sound (Mach number) is a similarity parameter. Other examples of similarity parameters are: Reynolds number, Stanton number and CFL number. Objects have similar aerodynamics at the same Mach number, rather than the same velocity, so that is used as a comparison.
The speed of sound is (to first order) only a function of temperature. Reduced temperature means that the speed of sound is slower.
Scramjet engines are tested between 20km and 50km altitude, where there is definitely an atmosphere. It can get very cold there though, so the speed of sound is much lower than at sea level.
Yes, but if "james brown is great" is changed to "john brown is great" sometime in the last 200 edits, how do I find the author? Not only that, how do I have any indication as to why it was changed? Was the fact verified wrong, changed out of spite or just a typographical error. None of these are fatal to wikipedia, but every small question as to whether the current version (and that's all that matters) is reliable is another nail in the coffin.
I would truly like to see wikipedia succeed, but I don't see that happening without an editorial system like that used at other encyclopaedias.
A lot of the articles that are "so short as to be scarecely worth the name" are on topics that would never have been covered by a traditional encyclopedia. Such "stub" articles probably shouldn't be counted in an evaluation of Wikipedia's merit unless they are of a topic that definitely should be included in any encyclopedia.
Where wikipedia says: There are 906538 total pages in the database. This includes "talk" pages, pages about Wikipedia, minimal "stub" pages, redirects, and others that probably don't qualify as articles. Excluding those, there are 352875 pages that are probably legitimate articles. There have been a total of 6752529 page edits since the software was upgraded (July 20, 2002). That comes to 7.45 average edits per page.
So wiki considers stubs, talks and redirects as articles. Which rather makes my point. In addition, there seems to be an average of between 10 and 30 edits to the legitimate articles. Is that even enough to get the broad facts right?
My point is that thousands of people make vague, unsubstantiated statements on wikipedia every day. That's not the same as hard facts, and its not valuable. I'm not saying that no article on wiki is a good as a traditional encyclopaedia, just that the vast majority currently are not, which is rather the point.
So what you're saying is that wikipedia is good because it has the potential to be good some time in the future? I think that wikipedia does have its strengths, but the current version of wiki is not that version, so there's not much point in arguing the greatness of wiki is in its system, when what that system has currently produced is a large number of articles which are so short as to be scarcely worth the name, a large number of articles which include partially/wholly untrue sections and a small number of really great articles.
My gut feeling is that the split is about 50/40/10, but perhaps you have better information. Until the wikipedia consists largely of verified information, its value remains greatly diminished.
Traditional works have several advantages over wiki works.
1. Versioning: If I say I got something from the 1975 Encyclopaedia Brittanica, you can go and check that I got my reference right. Then you can check if the fact was right in that version. With wiki, if I say I got it from the 20.2.2002 wiki, simply finding out if I got the quote right can be a problem.
2. Continuity: Most books fix errors as the version number increases. There is no gaurantee of continuity in the wiki system.
3. Editorship: Most other sources have clear lines about which author is responsible for a whole article, and one person who is responsible for seeing that facts are preserved and false statements are reviewed. There is no clear line of responsibility in a wiki article.
These three things make wikipedia less reliable than other media (but no less reliable than any other website)
I realise this is a bit offtopic, bit I moderated in the discussion on word frequency before I saw your post:
...
I have to learn German. I need the 86,000 most-commonly used German words. This would give me a nice target of words to get to know in the process of learning it
And since I'm also an English speaker in Germany I thought I'd note that typing "word"+"rank"+"german" into google returns plenty of sites including:
http://german.about.com/library/blwfreq01.htm
which only has the top 1000, but that's not a bad start.
In all honesty, I find that the word frequency depends a lot on your environment. Are you speaking in a pub with a bunch of welders or are you reading scientific literature? You'd be much better off just keeping a little notebook and writing down words you see more than once.
I also find that leo http://dict.leo.org/ is pretty good for a lot of stuff that doesn't make it into standard dictionaries.
Good luck,
Tony.
I'm also a graduate student in physics, and I couldn't disagree with you more. Newtonian dynamics is great for the really simple problems, and these days anything more complex simply isn't going to be done analytically unless you want something specific enough that you can afford to teach yourself Hamiltonian mechanics.
I study in Goettingen (I'm sure you know where that is.) and the mathematics department has a large hall of models of surfaces of least action, mainly done between 1900 and 1950. After the advent of computing most of the problems they were working on were done computationally.
I would just comment further that Newtonian mechanics has the enormous advantage of working mainly in directly measurable values, making errors easier to identify. In fact if you go into engineering, there's almost no system of calculation which doesn't work in directly measureable values, and so I think it simply makes sense to teach simple physics in those terms too.
It exists, and it's called an acousto-optic modulator. a lot of old fax machines used to use them to steer a laser onto the heat-sensitive paper. don't know what they use now though.
I bet if people from the 1920's see the world today, they would be alarmed by the technology and hitech gadgets
Yeah, but would the people of 1994 be so astonished?
I don't think so. What are we predicting for 10 years down the track? I'd bet that usable voice recognition technology, universal high-speed wireless and the first non-crap all-electric car won't make your eyes pop out, but they're a lot more likely than a brainwave monitor alarm clock.
Yes, but author-pays sucks for a lot of different reasons. The main one is what happens when a journal rejects an article _after_ the review process (when the costs have already been incurred). Who pays then?
Does the author of an accepted article pay for the reviewing costs if a Journal is crapflooded, or is the payment made before review? In addition, how do you tell the difference between author-pays and vanity publishing? I'd just note that there are very few author-pays journals in the physical sciences.
Yes, but the articles in the journals _are_ freely available, just not available for free. In many cases the articles are even available for less than the cost of a journal subscription: Just write to the author of the article you want, and I'm sure they'll be happy to provide you with a copy.
The question is whether, in addition to being freely available, whether the researchers should have to pay (for example) for web space to publish their articles. The further question is whether the raw data is also public property....
I appreciate some of your point, but could you explain how yould your problem have been solved by free journals? It seems like your problem was more a function of the inconvenience of pre-digital publishing than the prohibitive cost of the journals.
The employees of journals are paid by a private company. If the government wants to have the results of journals freely available, they can nationalize the company, or start their own journals. Requiring a company to provide its product for free is unsustainable (and possibly even unfair, no matter what you think of the scientific publishing system.
That's silly. That's like saying that because software can be copied at small cost, that it must be. To extend your metaphor: the way that the journals see it is that they've taken your method and written a program. Now you want the program for free, because you developed the method. See the point?
But the citizens already _do_ have free access to the information from the research. Internal reports, conference papers and often original data can be obtained if you ask the original researcher.
The point is:
1. Preparing a manuscript isn't free.
2. Publishing (even on the web) isn't free.
3. The journal owns the rights only to that particular compilation of the data, not to the data itself.
For instance the ESA requires all contracts to return a report which is then made publicly available.
Try searching the NASA server:
http://techreports.larc.nasa.gov/
if you can't get the Government-funded NASA paper you want.
Try this:
1) Make copy of original.
2) Build back areas which have been eroded with material of choice (clay/plaster).
3) Make copy of repaired carving.
Didn't you ever tidy up a cut and paste job using a photocopier?
And you can calculate the extra energy that spaceshipone would have to expend to get to that orbit, as opposed to an altitude of 100km with no sidewards movement. It's 62 times the energy. So LEO is still a few stepa away.
I realise that this is a bit redundant, but I read the slashdot artile linked to, and what to I see but:
Re:Fixed in new firmware, available here: (Score:3, Informative)
by Chucky B. Bear (785810) on Saturday June 05, @03:10PM (#9345433)
I've just upgraded to the latest firmware. It is NOT FIXED!!!! They have simply gone and changed the username and password to something else. There is STILL a default superuser account with password.
(You can find it yourselve by just taking similiar steps as in the securityfoces article.)
Maybe reading slashdot sometimes would be a good idea.