Detection Strategies for Extreme Mass Ratio Inspirals

The capture of compact stellar remnants by galactic black holes provides a unique laboratory for exploring the near horizon geometry of the Kerr spacetime, or possible departures from general relativity if the central cores prove not to be black holes. The gravitational radiation produced by these Extreme Mass Ratio Inspirals (EMRIs) encodes a detailed map of the black hole geometry, and the detection and characterization of these signals is a major scientific goal for the LISA mission. The waveforms produced are very complex, and the signals need to be coherently tracked for hundreds to thousands of cycles to produce a detection, making EMRI signals one of the most challenging data analysis problems in all of gravitational wave astronomy. Estimates for the number of templates required to perform an exhaustive grid-based matched-filter search for these signals are astronomically large, and far out of reach of current computational resources. Here I describe an alternative approach that employs a hybrid between Genetic Algorithms and Markov Chain Monte Carlo techniques, along with several time saving techniques for computing the likelihood function. This approach has proven effective at the blind extraction of relatively weak EMRI signals from simulated LISA data sets.Comment: 10 pages, 4 figures, Updated for LISA 8 Symposium Proceeding

Novel Dark Matter Models and Detection Strategies

We consider the impact of relaxing some typical assumptions about dark matter interactions, including isospin-invariance, elastic scattering and contact interactions. We show that detection strategies with neutrino detectors, gamma-ray searches, new direct detection experiments and collider searches can all provide complementary information. We argue that data from many such strategies may be necessary to gain a more complete understanding of dark matter interactions.Comment: 10 pages, 6 figures, to appear in the proceedings of CETUP* 201

SETI Detection Strategies for Single Dish Radio Telescopes

Radio Searches for Extra Terrestrial Intelligence aim at detecting artificial transmissions from extra terrestrial communicative civilizations. The lack of prior knowledge concerning these potential transmissions increase the search parameter space. Ground-based single dish radio telescopes offer high sensitivity, but standard data products are limited to power spectral density estimates. To overcome important classical energy detector limitations, two detection strategies based on asynchronous ON and OFF astronomical target observations are proposed. Statistical models are described to enable threshold selection and detection performance assessment

Detection strategies for bioassays based on liquid chromatography, fluorescence spectroscopy and mass spectrometry

New detection strategies for bioassays based on liquid chromatography,\ud fluorescence spectroscopy and mass spectrometry were developed and are\ud presented within this thesis

Optimal Watermark Embedding and Detection Strategies Under Limited Detection Resources

An information-theoretic approach is proposed to watermark embedding and detection under limited detector resources. First, we consider the attack-free scenario under which asymptotically optimal decision regions in the Neyman-Pearson sense are proposed, along with the optimal embedding rule. Later, we explore the case of zero-mean i.i.d. Gaussian covertext distribution with unknown variance under the attack-free scenario. For this case, we propose a lower bound on the exponential decay rate of the false-negative probability and prove that the optimal embedding and detecting strategy is superior to the customary linear, additive embedding strategy in the exponential sense. Finally, these results are extended to the case of memoryless attacks and general worst case attacks. Optimal decision regions and embedding rules are offered, and the worst attack channel is identified.Comment: 36 pages, 5 figures. Revised version. Submitted to IEEE Transactions on Information Theor

Detection strategies for scalar gravitational waves with interferometers and resonant spheres

We compute the response and the angular pattern function of an interferometer for a scalar component of gravitational radiation in Brans-Dicke theory. We examine the problem of detecting a stochastic background of scalar GWs and compute the scalar overlap reduction function in the correlation between an interferometer and the monopole mode of a resonant sphere. While the correlation between two interferometers is maximized taking them as close as possible, the interferometer-sphere correlation is maximized at a finite value of f*d, where `f' is the resonance frequency of the sphere and `d' the distance between the detectors. This defines an optimal resonance frequency of the sphere as a function of the distance. For the correlation between the Virgo interferometer located near Pisa and a sphere located in Frascati, near Rome, we find an optimal resonance frequency f=590 Hz. We also briefly discuss the difficulties in applying this analysis to the dilaton and moduli fields predicted by string theory.Comment: 26 pages, Latex, 4 Postscript figures. Various minor improvements, misprint in eqs. 42, 127, 138 corrected, references adde

Optimal Detection Strategies for an Established Invasive Forest Pest

When it comes to invasive species management, economists have focused on the trade-off between prevention of potential invasions and management of established populations. The intermediate step-detection of established populations on the landscape so that management can commence-has only recently received attention in the economics literature. A recent paper (Mehta et al., 2007) explores how biological and economic parameters affect optimal detection spending, recognizing that greater expenditures on detection can lead to smaller and more manageable population sizes upon detection because populations are discovered early. We build upon this framework by considering the optimal spatial allocation of detection effort when it is impossible to stop the advance of the main front of an invasive species, yet it is beneficial to detect and control sub-populations of the species that erupt ahead of the front. Our approach recognizes that the duration of management of sub-populations is constrained by the amount of time remaining before the main front arrives. Locations close to the front have less time remaining than locations that are more distant. These differences imply different levels of potential benefit from early detection; in particular, shorter management horizons translate into lower benefits from intervention. The optimal intensity of detection effort varies over space along with this variation in the benefits from management.Resource /Energy Economics and Policy,

Understanding trade pathways to target biosecurity surveillance

Increasing trends in global trade make it extremely difficult to prevent the entry of all potential invasive species (IS). Establishing early detection strategies thus becomes an important part of the continuum used to reduce the introduction of invasive species. One part necessary to ensure the success of these strategies is the determination of priority survey areas based on invasion pressure. We used a pathway-centred conceptual model of pest invasion to address these questions: what role does global trade play in invasion pressure of plant ecosystems and how could an understanding of this role be used to enhance early detection strategies? We concluded that the relative level of invasion pressure for destination ecosystems can be influenced by the intensity of pathway usage (import volume and frequency), the number and type of pathways with a similar destination, and the number of different ecological regions that serve as the source for imports to the same destination. As these factors increase, pressure typically intensifies because of increasing a) propagule pressure, b) likelihood of transporting pests with higher intrinsic invasion potential, and c) likelihood of transporting pests into ecosystems with higher invasibility. We used maritime containerized imports of live plants into the contiguous U.S. as a case study to illustrate the practical implications of the model to determine hotspot areas of relative invasion pressure for agricultural and forest ecosystems (two ecosystems with high potential invasibility). Our results illustrated the importance of how a pathway-centred model could be used to highlight potential target areas for early detection strategies for IS. Many of the hotspots in agricultural and forest ecosystems were within major U.S. metropolitan areas. Invasion ecologists can utilize pathway-centred conceptual models to a) better understand the role of human-mediated pathways in pest establishment, b) enhance current methodologies for IS risk analysis, and c) develop strategies for IS early detection-rapid response programs

Probing Isospin-Violating Dark Matter

We discuss experimental probes of isospin-violating dark matter (IVDM), including direct and indirect detection strategies. We point out the important role which IVDM plays in understanding recent data regarding low-mass dark matter, and describe strategies for finding evidence of IVDM at current and upcoming experiments.Comment: 8 pages, 3 figures, proceedings of the Symposium on Cosmology and Particle Astrophysics (CosPA2011