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  1. E

    Raspbian Permission Denied

    Look up Linux file permissions. To be very brief, you have to set the file to be executable before you can execute from the command line like you described. E.g. change the permission to allow the script to be executable: chmod +x then you can run it like you were trying to: ./
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    Are brains quantum computers?

    I've heard it claimed before that brains could be quantum computers (I think it was on Through the Wormhole). Is there any evidence of this? I'm thinking about reading up on quantum computation, but don't know anything about quantum mechanics yet. I'm mostly interested in machine learning...
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    Are you ready to Get Chipped?

    There would be insurmountable resistance to this idea. I imagine it would cause a sort of Crusade, as it would be seen as the "Mark of the Beast." Many Christians would assume they were living through the apocalypse, and whatever leader was pushing the idea would be the Anti-Christ, LOL. I live...
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    Does it matter in which language a given software was written in?

    Depends. Languages that are normally interpreted (Python) and hybrid languages (Java) usually run code slower than languages that are compiled (Fortran). Theoretically, you could compile or interpret any language, so language does not really matter in terms of performance. Where language does...
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    No one has made a program to solve these yet?

    To do that you'd first have to identify the sub-matrices that may contain letters, which may not be easy. Assuming that you could separate letters with high accuracy, I think you're solution would perform perform poorly on most captchas. Other problems are that the letters are usually skewed and...
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    Do MPI collective operations involve multiple hops?

    Consider the reduce operation for example. Do all nodes send data directly to the root? Or is there some structure where a node will receive data from a few other nodes, perform a reduction, then pass the intermediate results to other nodes?
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    What does a ellipsis directly following a summation mean?

    I've never seen this notation before. What does the ellipsis right after the first summation mean: \begin{equation} \label{aixi_eq} a_t^* = \arg\max\limits_{a_t}\sum\limits_{o_t r_t} \dots \max\limits_{a_{t+m}}\sum\limits_{o_{t+m} r_{t+m}}[r_t + \dots + r_{t+m}]...
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    Structure of Dolphin Brain and Comparison to Primates?

    Wow, thanks for all these references. Never heard of EQ before, and it's all very interesting. But, EQ seems to measure total brain mass, and from what I understand, it's mostly just the cortex that's responsible for higher-level thoughts, and all that stuff in the middle takes care of all...
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    Structure of Dolphin Brain and Comparison to Primates?

    Dolphins have larger brains than humans. So, why aren't they smarter than humans... or, are they? Are those sneaky Dolphins playing dumb? j/k It's my (very limited) understanding that the cortex is responsible for the higher levels of what we think of as intelligence. So, what's different...
  10. E

    Designing a 2d autonomous system

    Sounds like a good fit for Processing: Here's an example of GoL in Processing: [Broken]
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    C++, java, or python programming

    Although the OP seems to just want to know how to secure his computer, I'll offer my opinion for future reference. If you want to "hack" or "crack" in the sense of security related issues, you're probably going to want to focus on low-level programming languages, and really get a thorough...
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    MySQL: Schema & Model Explained - Self-Learning Guide

    Short answer: "Model" is a feature of MySQL Workbench, not really the database software itself. You use it to model out a database like you would on pen and paper. Once you've modeled a database, there's a menu option somewhere (I haven't used Workbench in a while :)) that automatically...
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    Im looking for free downloadable security programs

    For backups of documents (this isn't exactly security related), I use SpiderOak. You set up watch folders, it keeps track of the changes, and uploads your files to their servers. It uses an encrypted connection, and all your files are encrypted on their servers (The SpiderOak team can't...
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    C/C++ What program do you use to program using C++ or website design or anything

    My web programming experience consists of PHP, and a little bit of Ruby on Rails. For PHP, Netbeans is great. For RoR, I used Aptana Studio, which was nice as well. Like jedishrfu said, C++ is rarely used in website design. Server-side code is usually written in scripting languages or Java...
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    Artificial Intelligence and other data processing technologies

    I don't know anything about question 1. Question 2: ANNs are usually implemented in software. They're usually implemented as matrices for efficient computation. ANNs used in production environments are NOT simulations of how neuroscientists think the brain works. Traditional ANNs are...
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    Cooperating with AI

    Wouldn't simulating brains down to the molecular level be computationally intractable even with all the supercomputers in the world combined? And wouldn't trying to search through all the possible ways the neurons could be connected, trying to find a configuration that works well (i.e. genetic...
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    Probability: Male Smoker Probability Calculation

    I've always solved these problems by thinking about them in concrete terms. Say there are 100 people. 38 smoke 12 are female smokers So there must be 26 male smokers. 26/38 = ~0.6842
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    Need set notation help.

    Ok, I'm not very familiar with set notation. I was just wondering if the following is correct notation and means what I think: {x\inS : \existsy\inx, y\inW} S is a set of pairs of symbols (tuples of length 2 is the technical term I believe). W is a set of symbols. What I want is the...
  19. E

    Street tire static and kinetic friction coefficients?

    Oh, cool. Before I started this thread, I got search results from that site, but the site was down at the time. I didn't know what was on that site. Thanks.
  20. E

    Street tire static and kinetic friction coefficients?

    Anybody know where I can find data on normal street-tire friction coefficients on dry asphalt? I'd like both the static, and the kinetic coefficients. If not, can somebody give me a range of reasonable values? While I'm at it... What about racing slicks on asphalt? I found one source...
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    Are wages determined by the value of the product produced?

    LOL, at the Baywatch picture in that article. Perhaps it was hard to find qualified lifeguards with large breasts in that city, and now it's easier, so wages are declining? :) It's also worth noting that Newport Beach is "the richest city in the U.S.," with median home prices > $1 milliion...
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    Ideal Free Markets: Exploring Alternatives

    Hmm. That's kind of how labor unions, or maybe even Amish communities work. It's kind of like a directly democratic government itself. Seems to work ok in some circumstances. I could see a few special-case problems arising though. Consider a small town, with only one store; let's say a...
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    Ideal Free Markets: Exploring Alternatives

    Instead of incentives, governments could just directly fund the project. Like they do with highways, military, research, etc... In regards to some kind of contract where each person would benefit more than the share they pay, I'm not sure how you would assign a monetary value to clean air to...
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    Resource management problem

    LOL. Well, substitute just about any "first-world" country for the word American, and the results are the same.
  25. E

    Resource management problem

    Oh. No, I was responding to the OP originally. Yeah, that might be good formula on new planets (if we ever get that far) where building self-contained environments in hostile environments would be expensive. I'd think it would be uncomfortable living that close together to other families in...
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    Resource management problem

    Yeah, but they don't live off 5000 sq. ft. They don't get their fuel, food, and building materials from 5000 sq. ft.
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    Are wages determined by the value of the product produced?

    Is payment for employment determined by: 1) the value of the product produced, or 2) by the employees minimum requirements for survival, and the employer's need for employees in relation to the number of people competing for jobs? Seems to me like it's #2, but isn't that a little...
  28. E

    If poverty causes crime,

    Have you been to West Virginia? I have some cousins living there, and they've all been to prison. Last time I visited, I couldn't count how may times some random guy on the street would ask me if I wanted to buy some "rock," pills, or "bud." Also got into a fight. Everybody acted like they...
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    Resource management problem

    Not this argument again... A family can't survive on a 100' x 50' lot. Even if they could, I'd imagine they'd drive each other crazy and kill themselves. I will refer you to this page, just because I don't feel like searching for journal articles about this subject...
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    Why is sliding in dirt track racing faster?

    Ok, interesting. You're implying that the front-right tire has the most important job of turning the car on a left-hand turn. Makes sense.
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    Why is sliding in dirt track racing faster?

    Why would an extra set of wheels help when friction is not determined by surface area? From what I've read, the "slip angle" phenomenon is not about sliding or "slipping." It's about the deformation of the tire; no sliding involved. Again, all work to move the car both laterally and...
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    Why is sliding in dirt track racing faster?

    This line of reasoning is incorrect based on my understanding of Newtonian physics. There is already a force vector on every tire (rear and front) pointing into the turn when not sliding. That force vector is directly opposite of the momentum (right term?) vector trying to push the car...
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    Why is sliding in dirt track racing faster?

    I love that show. I hate driving front wheel drive cars in the winter. If you hit a patch of ice, the car just keeps going straight, and there's little you can do about it. In a rear wheel drive car, you can tap the gas a little to slide the rear end around. The British say "aluminum"...
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    Are Animals Honest? Do They Lie?

    I don't believe in free will. I'm also pretty sure that humans are animals :) This is a mostly philosophical question. Does honesty require consciousness? What is consciousness? Does honesty require a sense of morality? What is morality? Etc... I would say no, animals are not always...
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    Why is sliding in dirt track racing faster?

    Yeah, I was wondering why sliding on dirt is effective on dirt, and not asphalt. I was hypothesizing that the reason might lie in the fact that dirt is a collection of loose particles. Honestly, I'm surprised that a physicist hasn't stopped in here, and posted an explanation :) I figured it...
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    IT Outsourcing: Who's Responsible?

    The market is responsible for it. A corporation's sole goal is to cut costs and increase profits for the shareholders. If it's cheaper to outsource, then they must outsource. IT workers in India don't exactly make slave-wages either. From my experience with Elance, they typically charge...
  37. E

    Why is sliding in dirt track racing faster?

    Yeah, this is the theory I was trying to explain in my question. If the power was not delivered by the wheels, but with a rocket or something, the argument that sliding allows cars to supply more force toward the inside of the turn would make sense. But, I'm talking about normal cars that do...
  38. E

    Why is sliding in dirt track racing faster?

    Why is it often a faster way around a dirt track to slide around turns? The simplistic view that I got from Physics 101 says that the static friction coefficient is always higher than the sliding friction coefficient. So, that view would imply that a vehicle would be able to go around a turn...
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    Medical Is the cortex a scale-free network?

    Is it known, or widely believed, that the cortex is a scale-free network? I.E. Do a large percentage of neurons have a small number of connections to other neurons, and do a small percentage of neurons have a large number of connections to other neurons?
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    How to compute Gaussian Quadrature weights?

    My numerical analysis book doesn't explain it. It just tells you to use precomputed tables, and directs you to an out of print book from the 80's that I can't find anywhere. After searching, I found" in...
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    Strategies for constructing Maclaurin polynomials?

    I came across a problem in my homework to construct a MacLaurin polynomial of the nth degree for \sqrt{1+x}, and had some major problems. I gave up and looked up the answer on the internet, which was fairly complex: \sum \frac{(-1)^{n}(2n)!x^{n}}{(1-2n)(n!)^{2}(4^{n})} Well, I know I...
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    Symbolize Absence of evidence is not evidence of absence

    Well, the definition of a valid argument is if all the premises are true, then the conclusion must be true. So, a premise could be false, and the conclusion could be true, and it could be a valid argument. So yeah, "( (Premise ==> Conclusion) and (not Premise) ) ==> not Conclusion" is false...
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    Symbolize Absence of evidence is not evidence of absence

    Symbolize "Absence of evidence is not evidence of absence" This isn't homework. I was bored and ran across a blog that claimed the statement, "Absence of evidence is not evidence of absence" wasn't logical. It seems like common sense to me, so I was going to try prove it to be valid with...
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    Courses Need help picking math courses for CS.

    Hello. I'm a Computer Science major at a liberal arts college that doesn't require many mathematics courses. So I've decided to minor in mathematics because it seems important. My school gives a lot of freedom on which courses I can take to achieve this minor, and I have no idea which would be...
  45. E

    Did I solve this right?

    Here's the equation. \frac{mv^{2}}{r}=\frac{mg+C_{a}v^{2}cos\vartheta}{cos\vartheta-\mu sin\vartheta}\left(\mu cos\vartheta+sin\theta\right)-C_{a}v^{2}sin\vartheta After trying to solve for v, I got this: v=\sqrt{\frac{mg\mu cos\vartheta+mg sin\vartheta}{-2\mu C_{a}cos\vartheta-2\mu...