Software Listing of Author : "Travis Wiens"
- Complex Method of Optimization
- License: Freeware
- Price: 0.00


Implements the Complex Method of Constrained Optimization, as proposed by Box (1965), improved by Guin (1968) and Krus (1992), and following the method in Andresson (2001). This is capable of optimizing a "black-box" system with few constraints on the optimization function and requiring no knowledge of its derivatives. Includes an example, demonstrating training of an artificial neural network. More details are available at http://blog.nutaksas.com This was previously found at http://www.mathworks.com/matlabcentral/fil...objectType=FILE References Andersson J, "Multiobjective Optimization in Engineering Design - Application to fluid Power Systems." Doctoral thesis, Division of Fluid and Mechanical Engineering Systems, Department of Mechanical Engineering, Linkping University, 2001 http://citeseer.ist.psu.edu/562279.html Box, M.J.,...
- Publisher: Travis Wiens
- Date Released: 09-05-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Complex Optimization of a Recurrent Neural Network
- License: Freeware
- Price: 0.00


This package includes files for modelling nonlinear dynamic systems using a recurrent generalized neural network. The learning scheme uses the complex method of nonlinear nonderivative optimization, thereby avoiding the problems of computing the derivative of an infinite impulse response filter such as a recurrent neural network. This package includes files for modelling nonlinear dynamic systems using a recurrent generalized neural network. The learning scheme uses the complex method of nonlinear nonderivative optimization, thereby avoiding the problems of computing the derivative of an infinite impulse response filter such as a recurrent neural network. The example given is the modelling of a load-sensing hydraulic pump. The model output is the pump flow, as a response to inputs of pump pressure and the pressure in the control...
- Publisher: Travis Wiens
- Date Released: 18-01-2013
- Download Size: 256 KB
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- Platform: Matlab, Scripts
- Day Length
- License: Freeware
- Price: 0.00


Calculates the length of daylight for any day of the year and latitude. This uses Herbert Glarner's formulae which do not take into account refraction, twilight, size of the sun, etc http://herbert.gandraxa.com/herbert/lod.asp. An example is included See blog.nutaksas.com for more details/
- Publisher: Travis Wiens
- Date Released: 25-03-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Fast Circular (Periodic) Cross Correlation
- License: Freeware
- Price: 0.00


Uses fft to calculate the circular cross correlation of two periodic signal vectors.This is equivalent to xc(k)=sum(u1.*circshift(u2,k)), but much faster (on the order of 500 times faster for a 1024 point signal). The package also includes two examples. One checks the calculation against the definition. The second compares the speed of the fast algorithm to one based on the definition for a range of input vector sizes.
- Publisher: Travis Wiens
- Date Released: 26-03-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Forest Reverb Generator
- License: Shareware
- Price:


Generates the impulse response of an arbitrary forest of acoustically hard cylinders. Each tree scatters sound according to theory from Morse [1948]. Any number of trees of any radius may be placed at any position, limited only by memory and computational time. You can also set the maximum number of tree scatterings in each sound path. A .wav file may be generated for use in audio reverb units. A small forest example is included to calculate a 100 x 100 m forest with 10 trees and maximum 5 scatterings per path. Increasing the number of trees and scatterings increases the time and memory used. This is based on the idea behind Kyle Spratt's Treeverb (http://ccrma.stanford.edu/~kspratt/220c) although it was developed independently and appears to give different results.
- Publisher: Travis Wiens
- Date Released: 16-01-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Kasami Sequences, m-sequences, Linear Feedback Shift Registers
- License: Freeware
- Price: 0.00


Linear feedback shift registers (LFSR) are a simple method of generating sequences, including pseudorandom number sequences. The LFSR code provided is very unrestricted, allowing for any feedback polynomial, initial state or decimation factor. The code is written for a 32 bit LFSR, but minor alterations allow for 8-64 bit versions. A equivalent mex file is included, which runs approximately 100 times faster than the m file. Some of these LFSR sequences have special properties; a maximal length sequence (MLS or m-sequence) has a large autocorrelation at zero lag, with near zero autocorrelation elsewhere. This 'impulsive' autocorrelation function allows one to quickly determine the impulse response of a linear time invariant (LTI) system. An example of this system identification is provided. Maximal length sequences are also the base...
- Publisher: Travis Wiens
- Date Released: 16-06-2013
- Download Size: 20 KB
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- Platform: Matlab, Scripts
- Linear Regression with Errors in X and Y
- License: Shareware
- Price:


Calculates slope and intercept for linear regression of data with errors in X and Y. The errors can be specified as varying point to point, as can the correlation of the errors in X and Y. The uncertainty in the slope and intercept are also estimated. This follows the method in D. York, N. Evensen, M. Martinez, J. Delgado "Unified equations for the slope, intercept, and standard errors of the best straight line" Am. J. Phys. 72 (3) March 2004. The package includes an example and a Monte Carlo simulation verifying the estimated uncertainties. For more info, visit http://blog.nutaksas.com
- Publisher: Travis Wiens
- Date Released: 23-04-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Peak Interpolation
- License: Freeware
- Price: 0.00


Sometimes it is important to be able to estimate the peak of a sampled continuous function between the samples. This is called subsample peak interpolation and is used in radar, delay estimation, and communication. Typically one fits a model to the sampled data and then finds the maximum of the model. Two models that I have used are parabolas and Gaussian curves. Both have three parameters and can be fit exactly to three samples (even if the samples are not evenly spaced), and, as a bonus, closed form solutions exist for parameters. This package to demonstrate this procedure, including two examples. One demonstrates finding the peak of a function with unevenly spaced samples. The other shows an example of delay estimation to subsample accuracy.
- Publisher: Travis Wiens
- Date Released: 02-04-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- Radial Basis Function Network
- License: Shareware
- Price:


Radial basis functions are use for function approximation and interpolation. This package supports two popular classes of rbf: Gaussian and Polyharmonic Splines (of which the Thin Plate Spline is a subclass). The package also calculates line integrals between two points. For more information, see blog.nutaksas.com for academic papers.
- Publisher: Travis Wiens
- Date Released: 27-06-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts
- RBF Acoustic Tomography
- License: Freeware
- Price: 0.00


Acoustic tomography involves sending a sonic signal across a measurement area and timing how long it takes to travel the distance. A number of transducers are situated around the measurement area to achieve this. Since the absolute sonic speed is affected by temperature and wind speed, so is the time of flight. It is possible to reconstruct the temperature and wind velocity from the collection of time-of-flight data. This package gives an example of using radial basis function networks to allow for a linear solution to the inverse problem. The example data is from a Karman vortex street behind a cylinder.
- Publisher: Travis Wiens
- Date Released: 23-04-2013
- Download Size: 184 KB
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- Platform: Matlab, Scripts
- Subsample Delay Estimation
- License: Freeware
- Price: 0.00


This package includes a number of methods of determining the delay between two period signals. The delay may be calculated to subsample accuracy. Methods include: three-point interpolation using parabolic, Gaussian, or cosine functions; a phase method; and an iterative method. A simple example is included, as well as a more comprehensive example demonstrating the comparative performance of the methods under various signal properties. This is a companion to a forthcoming journal article, for more details, see http://blog.nutaksas.com or contact the author.
- Publisher: Travis Wiens
- Date Released: 21-01-2013
- Download Size: 10 KB
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- Platform: Matlab, Scripts