A real time imaging system for assessment and control swine thermal comfort

A real-time bioimaging system was developed to detect movement of group-housed pigs and to classify thermal comfort state of the pigs based on their resting patterns. This dissertation describes the background, theory, image features selection and analysis, image classification techniques, system architecture, and system performance with artificial and live pigs.;The system is based on the bioimaging control method: using animal\u27s thermal behavior as the ultimate biosensor that is used to reflect animal thermal comfortable levels. An automated real time image processing and control system is developed that monitors animal behavior and adjusts external devices according to the image classification results.;The system contains three major components: image capture component that grabs live animal images for analysis and display purposes; image processing component that detects animal movement and analyzes its thermal behaviors; and external device control component that adjusts environmental temperature to keep the temperature within the thermoneutral zone (TNZ). The system operates on a real-time basis with multiple input channels. It also displays live animal images and system control states for selected channels.;The system contains a rich set of image features, including image moment invariants, run-length frequency, animal body occupation ratio, and animal group shape compactness that are extracted as feature vectors. Different image classification methods were also investigated and a minimum distance was adopted as the measurement to distinguish the thermal comfort states of cold vs. comfortable. The system was designed to be body weight independent, and a sliding window was employed to update reference image feature sets so that classification is always based on the most recent information.;Rather than providing an academic prototype, the system is commercial application oriented. It provides real-time configurations so that users can modify system variables such as animal group size, image threshold value, channel selection and temperature set points on the run

Charged Scalar Perturbations around Garfinkle-Horowitz-Strominger Black Holes

We examine the stability of the Garfinkle-Horowitz-Strominger (GHS) black hole under charged scalar perturbations. We find that different from the neutral scalar field perturbations, only two numerical methods, such as the continued fraction method and the asymptotic iteration method, can keep high efficiency and accuracy requirements in the frequency domain computations. The comparisons of the efficiency between these two methods have also been done. Employing the appropriate numerical method, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the result obtained in the de Sitter and Anti-de Sitter black holes. Furthermore we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.Comment: 24 pages, 5 figure