scholarly journals Complex Orthogonal Decomposition Applied to Nematode Posturing

2013 ◽  
Vol 8 (4) ◽  
Author(s):  
B. F. Feeny ◽  
P. W. Sternberg ◽  
C. J. Cronin ◽  
C. A. Coppola
Keyword(s):  
Orthogonal Decomposition ◽  
Brief Assessment ◽  
Complex Modes ◽  
Characteristic Wavelength ◽  
Time Record ◽  
Forward Locomotion ◽  
Locomotion Mode ◽  
Short Time ◽  
Modal Coordinates ◽  
Complex Modal

The complex orthogonal decomposition (COD), a process of extracting complex modes from complex ensemble data, is summarized, as is the use of complex modal coordinates. A brief assessment is made on how small levels of noise affect the decomposition. The decomposition is applied to the posturing of Caenorhabditis elegans, an intensively studied nematode. The decomposition indicates that the worm has a multimodal posturing behavior, involving a dominant forward locomotion mode, a secondary, steering mode, and likely a mode for reverse motion. The locomotion mode is closer to a pure traveling waveform than the steering mode. The characteristic wavelength of the primary mode is estimated in the complex plane. The frequency is obtained from the complex modal coordinate's complex whirl rate of the complex modal coordinate, and from its fast Fourier transform. Short-time decompositions indicate the variation of the wavelength and frequency through the time record.

scholarly journals Complex Modal Decomposition Applied to Nematode Posturing

2009 ◽  
Author(s):  
B. F. Feeny ◽  
P. W. Sternberg ◽  
C. J. Cronin
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Orthogonal Decomposition ◽  
Brief Assessment ◽  
Ensemble Data ◽  
Complex Modes ◽  
Characteristic Wavelength ◽  
Locomotion Mode ◽  
Modal Coordinates ◽  
Complex Modal

The complex orthogonal decomposition (COD), a process of extracting complex modes from complex ensemble data, is summarized, as is the use of complex modal coordinates. A brief assessment is made on how small levels of noise affect the decomposition. The decomposition is applied to the posturing of a wild Caenorhabditis elegans nematode. The decomposition indicates that the worm has a multi-modal posturing behavior, involving at least a dominant locomotion mode and a secondary, steering mode. The locomotion mode is closer to a pure traveling waveform than the steering mode. The characteristic wavelength of the primary mode was estimated in the complex plane. Frequency was obtained from the complex modal coordinate’s complex whirl rate of the complex modal coordinate, and from its fast Fourier transform.

Characterizing Wave Behavior in a Beam Experiment by Using Complex Orthogonal Decomposition

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Rickey A. Caldwell ◽  
Brian F. Feeny
Keyword(s):  
Orthogonal Decomposition ◽  
Bernoulli Beam ◽  
Beam Experiment ◽  
Wave Numbers ◽  
Elastic Cord ◽  
The Impact ◽  
Euler Bernoulli Beam ◽  
Modal Coordinates ◽  
Wave Properties ◽  
Complex Modal

Complex orthogonal decomposition (COD) is applied to an experimental beam to extract the dispersive wave properties from response measurements. The beam is made of steel and is rectangular with a constant cross section. One end of the beam is free and is hung by a soft elastic cord. An impulse is applied to the free-end. The other end is buried in sand to absorb the wave as it travels from the impact site on the free-end; this effectively prevents reflections of the wave off the buried end and emulates a semi-infinite beam. The beam response is measured with an array of accelerometers, whose signals are integrated to obtain an ensemble of displacement signals. Acceleration responses are also compared in the frequency domain to predictions from the Euler–Bernoulli model. COD is applied to the displacement ensemble to obtain complex modal vectors and associated complex modal coordinates (COCs). The spatial whirl rates of nearly harmonic modal vectors are used to extract the modal wave numbers, and the temporal whirl rates of the modal coordinates are used to estimate the modal frequencies. The dispersion relationship between the frequencies and wave numbers compare favorably to those of the theoretical infinite Euler–Bernoulli beam.

Correlation of bridge stay cable models using short time record data

2000 ◽  
Author(s):  
Suzanne Smith ◽  
Matthew Johnson ◽  
Michael Schrader
Keyword(s):  
Stay Cable ◽  
Record Data ◽  
Time Record ◽  
Short Time

Enhanced Proper Orthogonal Decomposition for the Modal Analysis of Homogeneous Structures

2002 ◽  
Vol 8 (1) ◽  
pp. 19-40 ◽  
Author(s):  
S. Han ◽  
B. F. Feeny
Keyword(s):  
Finite Element ◽  
Proper Orthogonal Decomposition ◽  
Modal Analysis ◽  
Normal Modes ◽  
Orthogonality Condition ◽  
Orthogonal Decomposition ◽  
Analysis Tool ◽  
Homogeneous Structures ◽  
Proper Orthogonal ◽  
Modal Coordinates

Proper orthogonal decomposition (POD) is studied in an effort to increase its applicability as a modal analysis tool. A modification is proposed to make better use of spatial resolution and to accommodate arbitrary spacing in the discretization. The theory for this modification is rooted in the discrete approximation of the integral orthogonality condition for continuous normal modes. The modified POD is applied to a finite element beam and an experimental beam sensed with accelerometers, and the resulting proper orthogonal modes (POMs) are compared to the theoretical modes of the beam. The POMs are used as a basis for decomposing the signal ensemble into proper modal coordinates. The proper modal coordinates are used to evaluate the POMs and to match modes with modal frequencies and damping.

Complex Modal Analysis of the Swimming Motion of a Whiting

2011 ◽  
Author(s):  
B. F. Feeny ◽  
A. K. Feeny
Keyword(s):  
Modal Analysis ◽  
Wave Speed ◽  
Experimental Biology ◽  
Orthogonal Decomposition ◽  
Transverse Motion ◽  
Complex Mode ◽  
Swimming Motion ◽  
Single Complex ◽  
Complex Modal Analysis ◽  
Complex Modal

The kinematics of the transverse motion of a swimming fish are analyzed using a complex modal decomposition. Cinematographic images of a swimming whiting (Gadus merlangus) were obtained from the work of Sir James Gray (Journal of Experimental Biology, 1933). The position of the midline for each image was determined, and used to produce planar positions of virtual markers distributed along the midline of the fish. Transverse deflections of each virtual marker were used for the complex orthogonal decomposition of modes. This method was applied to a normal whiting and an amputated whiting, both of Gray’s paper. The fish motions were well represented by a single complex mode, which was used as a modal filter. The modal coordinate was also extracted. The mode and modal coordinate were used to estimate the frequency, wavelength, and wave speed. The amputated fish was compared to the non-amputated fish, and the different amount of traveling in the respective waveforms was quantified.

A Method of Decomposing Wave Motions

2006 ◽  
Author(s):  
B. F. Feeny
Keyword(s):  
Wave Motion ◽  
Wave Mode ◽  
Complex Signals ◽  
Wave Speeds ◽  
Complex Modes ◽  
Complex Correlation ◽  
Value Decomposition ◽  
Proper Orthogonal ◽  
The Relationship ◽  
Modal Coordinates

A method is presented for decomposing wave motion into its principle components. The basic idea is a generalization of proper orthogonal decomposition. The method involves the representation of real oscillatory signals as complex phasors. The relationship between complex modes and wave motion is explored. From an ensemble of complex signals, a complex correlation matrix is formed, and its complex eigensolution is the basis of the decomposition (like a complex singular value decomposition). The complex eigenvectors contain standing and traveling characteristics. A traveling index is proposed to quantify the relative degree of traveling and standing in a waveform. A method of dissecting a wave mode into its traveling and standing parts is also proposed. From the complex modes and modal coordinates, frequencies, wavelengths, and characteristic wave speeds can be obtained. The method is applied to traveling and standing-wave examples.

What the replication reformation wrought

2018 ◽  
Vol 41 ◽  
Author(s):  
Barbara A. Spellman ◽  
Daniel Kahneman
Keyword(s):  
Reform Movement ◽  
Short Time

AbstractReplication failures were among the triggers of a reform movement which, in a very short time, has been enormously useful in raising standards and improving methods. As a result, the massive multilab multi-experiment replication projects have served their purpose and will die out. We describe other types of replications – both friendly and adversarial – that should continue to be beneficial.

Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

2000 ◽  
Vol 179 ◽  
pp. 197-200
Author(s):  
Milan Minarovjech ◽  
Milan Rybanský ◽  
Vojtech Rušin
Keyword(s):  
Time Resolution ◽  
White Light ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Green Line ◽  
Periodic Intensity ◽  
Coronal Green Line ◽  
Significant Intensity ◽  
Short Time ◽  
Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

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