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  2. Minimum mean square error - Wikipedia

    en.wikipedia.org/wiki/Minimum_mean_square_error

    Standard method like Gauss elimination can be used to solve the matrix equation for .A more numerically stable method is provided by QR decomposition method. Since the matrix is a symmetric positive definite matrix, can be solved twice as fast with the Cholesky decomposition, while for large sparse systems conjugate gradient method is more effective.

  3. Orthogonality principle - Wikipedia

    en.wikipedia.org/wiki/Orthogonality_principle

    The orthogonality principle is most commonly used in the setting of linear estimation. [1] In this context, let x be an unknown random vector which is to be estimated based on the observation vector y. One wishes to construct a linear estimator ^ = + for some matrix H and vector c.

  4. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?

  5. Energy minimization - Wikipedia

    en.wikipedia.org/wiki/Energy_minimization

    In the field of computational chemistry, energy minimization (also called energy optimization, geometry minimization, or geometry optimization) is the process of finding an arrangement in space of a collection of atoms where, according to some computational model of chemical bonding, the net inter-atomic force on each atom is acceptably close to zero and the position on the potential energy ...

  6. Mean squared error - Wikipedia

    en.wikipedia.org/wiki/Mean_squared_error

    The MSE either assesses the quality of a predictor (i.e., a function mapping arbitrary inputs to a sample of values of some random variable), or of an estimator (i.e., a mathematical function mapping a sample of data to an estimate of a parameter of the population from which the data is sampled).

  7. MMSE - Wikipedia

    en.wikipedia.org/wiki/MMSE

    MMSE can refer to: Mini–mental state examination, a questionnaire to measure cognitive impairment; Minimum mean square error, an estimation method that minimizes the mean square error; Multimedia Messaging Service Environment, the servers in a mobile telephony network required for Multimedia Messaging Service messaging.

  8. Standard addition - Wikipedia

    en.wikipedia.org/wiki/Standard_addition

    Note that this is not limited to liquid samples. In atomic absorption spectroscopy, for example, standard additions are often used with solid as the sample. [6] In atomic emission spectroscopy, background signal cannot be resolved by standard addition. Thus, background signal must be subtracted from the unknown and standard intensities prior to ...

  9. Orders of magnitude (molar concentration) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(molar...

    List of orders of magnitude for molar concentration; Factor (Molarity) SI prefix Value Item 10 −24: yM 1.66 yM: 1 elementary entity per litre [1]: 8.5 yM: airborne bacteria in the upper troposphere (5100/m 3) [2]