Daya Abbott - Profile on Academia.edu (original) (raw)

Papers by Daya Abbott

In the recent years, it has been shown that terahertz (or T-ray) spectroscopy is a versatile tool... more In the recent years, it has been shown that terahertz (or T-ray) spectroscopy is a versatile tool for biosensing and safety applications. This is due to the fact that the THz-spectra of many biomolecules show very characteristic, distinct spectroscopic features. Furthermore, most non-metallic packaging materials are nearly transparent in this frequency range (0.1 -6 THz, 3 cm -1 -200 cm -1 ), so that it is possible to non-invasively identify even sealed substances like pharmaceuticals, illicit drugs or explosives by their spectroscopic signatures. This opens a significant potential for a wide range of applications from quality control of pharmaceutical substances via safety applications through to biomedical applications. The individual spectroscopic features below approximately 5 THz that spurred the increased world wide interest in T-ray spectroscopy are mainly due to intermolecular rather than intramolecular vibrations in the polycrystalline samples. The spectra of more complex biomolecules, like proteins and nucleotides, typically show less or even no sharp features, due to the lack of long-range intermolecular order. Furthermore, due to the typically significantly smaller sample amount, the signal to noise ratio is strongly increased. Water shows a strong absorption in this frequency range, which all together makes real biomedical applications of T-ray spectroscopy rather difficult. Yet, by combining a careful sample preparation, novel experimental techniques and an advanced signal processing of the experimental data we can still clearly distinguish between even complex biomolecules and therefore demonstrate the potential the technique holds for biomedical applications.

The development of terahertz radiation (T-rays) is spurring new applications in spectroscopy and ... more The development of terahertz radiation (T-rays) is spurring new applications in spectroscopy and imaging. To maximize the use of T-rays in more applications, a high average terahertz power is needed. Rather than using fast diodes or laser sources, this paper will show that a synchrotron can generate high average power T-rays. This is achieved by creating an electron bunch in the synchrotron ring with high intensity in the terahertz frequency region via Thomson scattering.

Arxiv preprint cs/0404019, 2004

This paper explores the use of genetic algorithms for the design of networks, where the demands o... more This paper explores the use of genetic algorithms for the design of networks, where the demands on the network fluctuate in time. For varying network constraints, we find the best network using the standard genetic algorithm operators such as inversion, mutation and crossover. We also examine how the choice of genetic algorithm operators affects the quality of the best network found. Such networks typically contain redundancy in servers, where several servers perform the same task and pleiotropy, where servers perform multiple tasks. We explore this trade-off between pleiotropy versus redundancy on the cost versus reliability as a measure of the quality of the network.

ACM Transactions on Sensor Networks, 2014

Radio connectivity in wireless sensor networks is highly intermittent due to unpredictable and ti... more Radio connectivity in wireless sensor networks is highly intermittent due to unpredictable and time-varying noise and interference patterns in the environment. Because link qualities are not predictable prior to deployment, current deterministic solutions to unreliable links, such as increasing network density or transmission power, require overprovisioning of network resources and do not always improve reliability. We propose a new dual-radio network architecture to improve communication reliability in wireless sensor networks. Specifically, we show that radio transceivers operating at well-separated frequencies and spatially separated antennas offer robust communication, high link diversity, and better interference mitigation. We derive the optimal parameters for the dual-transceiver setup from frequency and space diversity in theory. We observe that frequency diversity holds the most benefits as long as the antennas are sufficiently separated to prevent coupling. Our experiments ...

Fluctuations and noise in biological, biophysical, and biomedical systems II:(Maspalomas, 26-28 May 2004)

SPIE proceedings series, 2004

In the recent years, it has been shown that terahertz (or T-ray) spectroscopy is a versatile tool... more In the recent years, it has been shown that terahertz (or T-ray) spectroscopy is a versatile tool for biosensing and safety applications. This is due to the fact that the THz-spectra of many biomolecules show very characteristic, distinct spectroscopic features. Furthermore, most non-metallic packaging materials are nearly transparent in this frequency range (0.1 -6 THz, 3 cm -1 -200 cm -1 ), so that it is possible to non-invasively identify even sealed substances like pharmaceuticals, illicit drugs or explosives by their spectroscopic signatures. This opens a significant potential for a wide range of applications from quality control of pharmaceutical substances via safety applications through to biomedical applications. The individual spectroscopic features below approximately 5 THz that spurred the increased world wide interest in T-ray spectroscopy are mainly due to intermolecular rather than intramolecular vibrations in the polycrystalline samples. The spectra of more complex biomolecules, like proteins and nucleotides, typically show less or even no sharp features, due to the lack of long-range intermolecular order. Furthermore, due to the typically significantly smaller sample amount, the signal to noise ratio is strongly increased. Water shows a strong absorption in this frequency range, which all together makes real biomedical applications of T-ray spectroscopy rather difficult. Yet, by combining a careful sample preparation, novel experimental techniques and an advanced signal processing of the experimental data we can still clearly distinguish between even complex biomolecules and therefore demonstrate the potential the technique holds for biomedical applications.

The development of terahertz radiation (T-rays) is spurring new applications in spectroscopy and ... more The development of terahertz radiation (T-rays) is spurring new applications in spectroscopy and imaging. To maximize the use of T-rays in more applications, a high average terahertz power is needed. Rather than using fast diodes or laser sources, this paper will show that a synchrotron can generate high average power T-rays. This is achieved by creating an electron bunch in the synchrotron ring with high intensity in the terahertz frequency region via Thomson scattering.

Arxiv preprint cs/0404019, 2004

This paper explores the use of genetic algorithms for the design of networks, where the demands o... more This paper explores the use of genetic algorithms for the design of networks, where the demands on the network fluctuate in time. For varying network constraints, we find the best network using the standard genetic algorithm operators such as inversion, mutation and crossover. We also examine how the choice of genetic algorithm operators affects the quality of the best network found. Such networks typically contain redundancy in servers, where several servers perform the same task and pleiotropy, where servers perform multiple tasks. We explore this trade-off between pleiotropy versus redundancy on the cost versus reliability as a measure of the quality of the network.

ACM Transactions on Sensor Networks, 2014

Radio connectivity in wireless sensor networks is highly intermittent due to unpredictable and ti... more Radio connectivity in wireless sensor networks is highly intermittent due to unpredictable and time-varying noise and interference patterns in the environment. Because link qualities are not predictable prior to deployment, current deterministic solutions to unreliable links, such as increasing network density or transmission power, require overprovisioning of network resources and do not always improve reliability. We propose a new dual-radio network architecture to improve communication reliability in wireless sensor networks. Specifically, we show that radio transceivers operating at well-separated frequencies and spatially separated antennas offer robust communication, high link diversity, and better interference mitigation. We derive the optimal parameters for the dual-transceiver setup from frequency and space diversity in theory. We observe that frequency diversity holds the most benefits as long as the antennas are sufficiently separated to prevent coupling. Our experiments ...

Fluctuations and noise in biological, biophysical, and biomedical systems II:(Maspalomas, 26-28 May 2004)

SPIE proceedings series, 2004