Spectral Selection of Very-Low Frequencies Processes

This paper considers an anytime strategy to implement controllers that react to changing computational resources. The anytime controllers developed in this paper are suitable for cases when the time scale of switching is in the order of the task execution time, that is, on the time scale found commonly with sporadically missed deadlines. This paper extends the prior work by developing frequency-weighted anytime controllers. The selection of the weighting function is driven by the expectation of the situations that would require anytime operation. For example, if the anytime operation is due to occasional and isolated missed deadlines, then the weighting on high frequencies should be larger than that for low frequencies. Low frequency components will have a smaller change over one sample time, so failing to update these components for one sample period will have less effect than with the high frequency components. An example will be included that applies the anytime control strategy to a model of a DC motor with deadzone and saturation nonlinearities.

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Novel Organization of Genes Involved in Prophage Excision Identified in the Temperate Lactococcal Bacteriophage TP901-1

Journal of Bacteriology ◽

10.1128/jb.181.23.7291-7297.1999 ◽

1999 ◽

Vol 181 (23) ◽

pp. 7291-7297 ◽

Cited By ~ 60

Author(s):

Anne Breüner ◽

Lone Brøndsted ◽

Karin Hammer

Keyword(s):

Basic Protein ◽

Genetic Material ◽

Gene Encoding ◽

Low Frequencies ◽

Uracil Phosphoribosyltransferase ◽

Phage Integrase ◽

The Family ◽

Phage Protein ◽

Selection Of

ABSTRACT In this work, the phage-encoded proteins involved in site-specific excision of the prophage genome of the temperate lactococcal bacteriophage TP901-1 were identified. The phage integrase is required for the process, and a low but significant frequency of excision is observed when the integrase is the only phage protein present. However, 100% excision is observed when the phage protein Orf7 is provided as well as the integrase. Thus, Orf7 is the TP901-1 excisionase, and it is the first excisionase identified that is used during excisive recombination catalyzed by an integrase belonging to the family of extended resolvases. Orf7 is a basic protein of 64 amino acids, and the corresponding gene (orf7) is the third gene in the early lytic operon. This location of an excisionase gene of a temperate bacteriophage has never been described before. The experiments are based on in vivo excision of specifically designed excision vectors carrying the TP901-1 attP site which are integrated intoattB on the chromosome of Lactococcus lactis. Excision of the vectors was investigated in the presence of different TP901-1 genes. In order to detect very low frequencies of excision, a method for positive selection of loss of genetic material based upon the upp gene (encoding uracil phosphoribosyltransferase) was designed, since upp mutants are resistant to fluorouracil. By using this system, frequencies of excision on the order of 10−5 per cell could easily be measured. The described selection principle may be of general use for many organisms and also for types of deletion events other than excision.

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Influence of Materials on the Performance Limits of Microactuators

MRS Proceedings ◽

10.1557/proc-1052-dd07-03 ◽

2007 ◽

Vol 1052 ◽

Author(s):

Prasanna Srinivasan ◽

S. Mark Spearing

Keyword(s):

Thin Films ◽

Shape Memory ◽

High Performance ◽

Low Frequency ◽

Beam Theory ◽

Performance Limits ◽

Low Frequencies ◽

Thermal Actuators ◽

Work Volume ◽

Selection Of

AbstractThe selection of actuators at the micro-scale requires an understanding of the performance limits of different actuation mechanisms governed by the optimal selection of materials. This paper presents the results of analyses for elastic bi-material actuators based on simple beam theory and lumped parameter thermal models. Comparisons are made among commonly employed actuation schemes (electro-thermal, piezoelectric and shape memory) at micro scales and promising candidate materials are identified. Polymeric films on Si subjected to electro-thermal heating are optimal candidates for high displacement, low frequency devices while ferroelectric thin films of Pb-based ceramics on Si/ DLC are optimal for high force, high frequency devices. The ability to achieve ∼10 kHz at scales < 100μm make electro-thermal actuators competitive with piezoelectric actuators considering the low work/volume obtained in piezoelectric actuation (∼ 10−8J.m−3.mV−2). Although shape memory alloy (SMA) actuators such as Ni-Ti on Si deliver larger work (∼ 1 J.m−3K−2) than electro-thermal actuators at relatively low frequencies (∼ 1 kHz), the critical scale associated with the cessation of the shape memory effect forms the bounding limit for the actuator design. The built-in compressive stress levels (∼ 1GPa) in thin films of Si and DLC could be exploited for realizing a high performance actuator by electro-thermal buckling.

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Active-grating monochromator for the spectral selection of ultrashort pulses

Optics Express ◽

10.1364/oe.21.012996 ◽

2013 ◽

Vol 21 (11) ◽

pp. 12996 ◽

Cited By ~ 3

Author(s):

Fabio Frassetto ◽

Stefano Bonora ◽

Caterina Vozzi ◽

Salvatore Stagira ◽

Erika Zanchetta ◽

...

Keyword(s):

Ultrashort Pulses ◽

Grating Monochromator ◽

Spectral Selection ◽

Selection Of

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Grating monochromators for the spectral selection of femtosecond extreme-ultraviolet pulses

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2010.10.003 ◽

2011 ◽

Vol 635 (1) ◽

pp. S75-S79 ◽

Cited By ~ 3

Author(s):

Fabio Frassetto ◽

Luca Poletto

Keyword(s):

Extreme Ultraviolet ◽

Spectral Selection ◽

Selection Of

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The Faraday threshold in small cylinders and the sidewall non-ideality

Journal of Fluid Mechanics ◽

10.1017/jfm.2013.324 ◽

2013 ◽

Vol 729 ◽

pp. 496-523 ◽

Cited By ~ 22

Author(s):

W. Batson ◽

F. Zoueshtiagh ◽

R. Narayanan

Keyword(s):

Contact Line ◽

Mode Selection ◽

Single Mode ◽

Linear Stability Theory ◽

Viscous Effects ◽

Low Frequencies ◽

Dimension 2 ◽

First Time ◽

Wetting Fluid ◽

Selection Of

AbstractIn this work we investigate, by way of experiments and theory, the Faraday instability threshold in cylinders at low frequencies. This implies large wavelengths where effects from mode discretization cannot be ignored. Careful selection of the working fluids has resulted in an immiscible interface whose apparent contact line with the sidewall can glide over a tiny film of the more wetting fluid, without detachment of its actual contact line. This unique behaviour has allowed for a system whose primary dissipation is defined by the bulk viscous effects, and in doing so, for the first time, close connection is seen with the viscous linear stability theory for which a stress-free condition is assumed at the sidewalls. As predicted, mode selection and co-dimension 2 points are observed in the experiment for a frequency range including subharmonic, harmonic, and superharmonic modes. While agreement with the predictions are generally excellent, there are deviations from the theory for certain modes and these are explained in the context of harmonic meniscus waves. A review of previous work on single-mode excitation in cylinders is given, along with comparison to the viscous model and analysis based upon the conclusions of the current experiments.

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SOME TECHNICAL ASPECTS OF REFLECTION SEISMIC PROSPECTING IN THE SAHARA

Geophysics ◽

10.1190/1.1438503 ◽

1958 ◽

Vol 23 (3) ◽

pp. 557-573 ◽

Cited By ~ 1

Author(s):

M. Pieuchot ◽

H. Richard

Keyword(s):

Seismic Reflection ◽

Signal To Noise Ratio ◽

Small Signal ◽

Signal To Noise ◽

Low Frequencies ◽

Technical Aspects ◽

Reflection Seismic ◽

Linear Dimensions ◽

Single Trace ◽

Selection Of

The small signal‐to‐noise ratio encountered in the Sahara required the development of special techniques. The gentle dips and low frequencies permitted the use of a pattern of 100 shot holes recorded by an array of 100 or more geophones per trace with the linear dimensions of the arrays of the order of 100 m. The large structural dimensions allowed the compositing of as many as 5 records into a single trace. Seismic reflection exploration was made economically feasible by the use of pneumatic hammers for drilling and the less expensive nitrates for explosives. The experimental procedures leading to the selection of the techniques are described.

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