Noise and time-dependent fluctuations are usually undesirable signals. However,
they have many applications. This dissertation deals with two kinds of sensing
applications of fluctuation and noise: soil bulk density assessment and bacterium sensing.
The measurement of Vibration-Induced Conductivity Fluctuations (VICOF)
provides information about the bulk density and other parameters of soils. Bulk density
is the physical property of soils that is important to both the agriculture and construction
industries. The traditional measurements of soil bulk density are often time-consuming,
expensive or destructive. To determine the soil bulk density without the above
drawbacks, the VICOF measurement scheme was proposed. The research of VICOF in
this dissertation includes two parts: the initial phase of study and the new methods and
their theory. In the initial phase of study, the simple experiments, theory, and simulations
of VICOF were tested for relations between the soil bulk density, wetness, salinity, and
the VICOF data. Then, new measurement arrangements and their theoretical models
were proposed to improve the weaknesses of the initial approach (such as large scattering of data due to loose and heavy contacts) and to calculate the relationship
between the measured signals and the electromechanical transport parameters of the soils.
The bacterium sensing study in this dissertation was proposed to explore simple,
practical, rapid, sensitive, specific, portable, and inexpensive ways to detect and
recognize bacteria by Fluctuation-Enhanced Sensing (FES). One such potential way of
bacterium sensing is to analyze their odor. The research of bacterium sensing also
includes two parts: the initial phase of study and the new methods and their theory. The
initial phase study was proposed to explore the possibility of detecting and identifying
bacteria by sensing their odor via FES with commercial Taguchi sensors. Then the
subsequently developed new methods and their theory provide a simple way to generate
binary patterns with perfect reproducibility based on the spectral slopes in different
frequency ranges at FES. This new type of signal processing and pattern recognition is
implemented at the block diagram level using the building elements of analog circuitries
and a few logic gates with total power consumption in the microWatts range.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-12-8682 |
| Date | 2010 December 1900 |
| Creators | Chang, Hung-Chih |
| Contributors | Kish, Laszlo B. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | application/pdf |
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