We define a novel, basic, unsupervised learning problem learning the lowest density homogeneous hyperplane separator of an unknown probability distribution. This task is relevant to several problems in machine learning, such as semi-supervised learning and clustering stability. We investigate the question of existence of a universally consistent algorithm for this problem. We propose two natura...

Vehicles are major sources of air pollutant emissions, and individuals living near large roads endure high exposures and health risks associated with traffic-related air pollutants. Air pollution epidemiology, health risk, environmental justice, and transportation planning studies would all benefit from an improved understanding of the key information and metrics needed to assess exposures, as ...

Effect of long-term exposure to low or moderate lead acetate (PbAc) on growth, serum lipid profile and some biochemical parameters was investigated. Male albino rats were divided into five groups and given 0, 0.025, 0.05, 0.1 and 0.3% PbAc in drinking water for 11 months. There was a significant decrease in body weight in rats given 0.1 % PbAc at the third month of lead treatment (p<0.01) compa...

We report a method for producing stable low-density polymer films by using supercritical carbon dioxide (scCO2). Two different molecular weight polystyrene films with various thicknesses were exposed to scCO2 along the density fluctuation ridge in P – T phase diagram. The swollen structures could be then frozen by flash evaporation of CO2 without forming additional voids. X-ray reflectivity dat...

We study density-based clustering under low-noise conditions. Our framework allows for sharply defined clusters such as clusters on lower dimensional manifolds. We show that accurate clustering is possible even in high dimensions. We propose two data-based methods for choosing the bandwidth and we study the stability properties of density clusters. We show that a simple graph-based algorithm kn...