SUNFEST Projects Summer 1996
TRANSDERMAL DNA DELIVERY USING AN ULTRASONIC TRANSDUCER
Corinne Bright (Engineering/Biology) - Swarthmore College
Recent advances in transdermal delivery have allowed for the administration
of higher molecular weight drugs noninvasively with the aid of ultrasound.
Previously, only lower molecular weight drugs could be absorbed through
the relatively impermeable skin as larger molecules cannot be readily taken
up. The goal of this research was to extend the transdermal application
of ultrasound beyond drug delivery to gene therapy with the administration
of a DNA plasmid through the skin. This research was founded in the hopes
that eventually a transdermal patch containing a transducer could deliver
DNA to the bloodstream in a painless technique using low frequency ultrasound.
Though this goal has not yet been reached, I had the opportunity to vary
some of the many parameters involved in this research including frequency,
pulse length and intensity among others. In vivo testing on mice
allowed for the exploration of the advantages and constraints of transdermal
DNA delivery using ultrasound on a complex biological system.
VOWEL RECOGNITON USING NEURAL NETWORKS
Joshua Vatsky (EE) - University of Pennsylvania
Despite the seeming ease with which humans extract meaningful information
from the speech signal, achieving this with man-made systems has proven
difficult. We hear and understand effort-lessly, yet how we do this remains
a mystery. The methods which should be used to construct machines capable
of recognizing speech are therefore unclear. Various methods have been
and are being explored to allow machines to recognize speech. The approach
employed here uses neural networks to examines speech at the phoneme level.
VOICING DETECTION USING HOMOMORPHIC SPEECH PROCESSING AND FILTER BANK ANALYSIS
Rachel Branson (Engineering) - Lincoln University
An effective method of detecting voicing has been desired as a means
of preparing speech samples for analysis. Currently, the two methods used
are Cepstrum and Filter Bank Analysis. However, neither one is always accurate
in its detection of voicing. This report will discuss the importance of
voicing detection and the processes of Cepstrum Analysis in detail. This
report will also discuss the steps taken to combine the two processes to
create a more accurate means of voicing detection.
AUTOMATIC SPEECH RECOGNITION OF FRICATIVES ON THE CORTICON NEURAL COMPUTER USING FEATURE EXTRACTION
George R. Koch III (Bioengineering) - University of Pennsylvania
This project represents the synthesis of two previous independently
done projects, the first being Christopher D. Donham's doctoral thesis
from 1995 and the second being Ahmed Ali's research done in 1996. The goal
is to implement Ali's simulated neural network for fricatives onto the
Analog Neural Computer using the details and feature extractors from Donham's
thesis. A feed-forward network is designed, consisting of level detectors
followed by decision makers. Sounds from a speech database go to a bank
of bandpass filters which separate the sounds in order of increasing frequency
into 16 bands. The output of these bands is presented to the neural computer.
The level detectors analyze the energy content per band, and send that
information to the decision makers, which then decides whether or not a
phoneme is the fricative it was designed to detect.
PATTERN RECOGNITION USING A NEURAL NETWORK
Sandro Molina-Cabrera (Biology) University of Puerto Rico
During the summer I have worked with pattern recognition using neural
networks. The purpose of this project is to introduce me to the field of
pattern recognition using neural networks. This research can be segmented
into three parts: first, to acquire a background on neural networks, back
propagation, pattern recognition and Matlab; second, to build a library
of input vectors that are used to train and test the neural network; and
third, to program, simulate, train and expand the neural network. In this
paper, we describe the first part and the beginning of the second and third
segments. We provide an introduction to neural networks and pattern recognition
based on what we have learned. We also provide a quick introduction to
Matlab and its use as a neural network simulator. Problems confronted during
the development of the neural network will be discussed as well as the
future directions of this research.
ANALYSIS OF EXERGY LOSSES IN COMBUSTION OF METHANE
Alison Davis (Chemistry) - Harvard University
Exergy is an important thermodynamic property which measures the useful
work that can be produced by a substance, or the amount of work needed
to complete a process. Unlike energy, exergy is not conserved; analysis
of exergy losses provides information as to where the real inefficiencies
in a system lie. In this paper, the exergy losses inherent in combustion
are calculated and the effects of changing combustion parameters are determined.
A simplified model of combustion is proposed that will allow a detailed
breakdown of exergy losses to be made.
A SYSTEM FOR SPECTROELECTROCHEMICAL CHARACTERIZATION OF THIN FILMS FOR ELECTROCHEMICAL SENSORS
Brian Tyrrell (EE) - University of Pennsylvania
A device has been developed for the spectroelectrochemical characterization
of thin films for electrochemical microsensors. This consists of a reaction
chamber containing a transparent indium tin oxide (ITO) working electrode,
a gold counter electrode, and a silver-silver chloride reference electrode.
The reaction chamber is constructed using a standard 5 mL spectrophotometer
cuvette, and allows for easy delivery of fluids while mounted in a spectrophotometer.
Changes in the absorption spectrum of a K3Fe(CN)6
solution due to the redox processes taking place during cyclic voltammetry
have been successfully observed using this device.
Rachel Green (Engineering) - Lincoln University
The pyroelectric anemometer (PA), a thermal gas flow meter device, offers
some interesting advantages over other existing means of thermal mass flow
measurements. A study of the effectiveness of PA systems on unstable (turbulent)
flows was conducted. In this report we present results acquired over the
summer using various types of PA systems.
These systems were employed in the University of Pennsylvania 2" Suction
Wind Tunnel (PSWT). Additional structures built to control the flow in
the PSWT. Measurements were carried out with these structures. Results
of the various measurements conducted this summer
are presented in graphical form and some discussion presented. The
data is available in disk format.