Recent content by azay

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    Fourier effect of time shift + convolution

    Ok, I know the Fourier effect of a time shift is a multiplication with an exponential: x(t-t0) → exp(-j2∏f*t0)X(f) Now say Y(f) is the Fourier transform of y(t). What I am wondering what is the difference in the Fourier space when convolving Y(f) with either X(f) or exp(-j2∏f*t0)X(f)...
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    Homogeneous least squares

    Given a homogeneous linear least squares problem: A^{T}y=0 What is the difference between minimizing y^{T}AA^{T}y (the least square error) and: y^{T}AA^{+}y=y^{T}A(A^{T}A)^{-1}A^{T}y ? Thanks.
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    Markov chains: period of a state

    Okay. Thanks for helping me out!
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    Markov chains: period of a state

    It was just a theoretical example. Why is it not possible to have probability 1 for all transitions except A->B and A->E? (the sum of the probabilities of A->B and A->E is obviously 1, with both being not equal to 0). There are no other transitions except the ones I listed. It is a valid Markov...
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    Markov chains: period of a state

    There are no other possible transitions. Only A->B and A->E are possible. The gcd is 2...
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    Markov chains: period of a state

    Yes, I had seen this pattern. I just found kind of quirky because in many places where they give intuition about this definition they say as if you can visit for every multiple of 2. But thanks for confirming :).
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    Markov chains: period of a state

    It's not possible to go from A to B to A in my example. Say: A->B->C->D->A (4 steps) is possible and A->E->F->...->A (18 steps) is possible. I don't see how it is possible to get back in 2 steps... What am I missing?
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    Markov chains: period of a state

    But in my example it is not possible to get back to state i in 2 steps, while 2 is the gcd. How does this make '2' the minimum? The minimum is '4'.
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    Markov chains: period of a state

    Hello, I am trying to understand the intuition of the definition of the period of a state in a Markov chain. Say for example we can go from state i to state i in either 4 steps or either 18 steps. gcd(4,18)=2, with gcd=greatest common divisor. So the period of state i is equal to 2. I...
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    Statistics: check independence of two continuous variables

    Homework Statement I have a table of paired measurements: IQ and brainsize of a person. Question: is there a significant connection between brainsize and IQ?Homework Equations / The Attempt at a SolutionThe only test in my course notes that checks indepedence of continuous variables is a...
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    Relationship b/w Binomial, CLT & Poisson Distrib.

    From the central limit theorem the binomial distribution can be approximated by a normal distribution N(0,1). But the binomial distribution can also be approximated by a poisson distribition. Does this mean there is a relationship between the normal distribution and the poisson distribution...
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    Does x Have to be Greater Than 0 If y is Chosen from (0,1)?

    Given the fact that the following inequality must hold; x > y-1 For all y \in ]0,1[ (an open interval) and given the fact that one can choose y After one chooses x, can one then state that x > 0 holds? My idea was to say that at least x >= 0 holds because: 1) Someone picks a negative x...
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    Gradient & Normal: Intuition & Definition

    It states in course notes: ------------------------------------------- If y = f(x) defines a surface in (n+1) dimensional space then the normal is defined as the (n+1)-dimensional vector: (\frac{\partial f(x)}{\partial x1},(\frac{\partial f(x)}{\partial x2},...,(\frac{\partial f(x)}{\partial...
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    Vandermonde Matrix, Polynomial Interpolation & Orthogonal Basis

    In polynomial interpolation: I see some connection between: The Vandermonde matrix, the monomial basis and the fact that 'the monomial basis is not a good basis because it's components are not very orthogonal'. Now, I still don't really grasp sufficiently the reason why exactly a Vandermonde...
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