Diesel exhaust is a mixture of combustion gases and ultrafine particles coated with organic compounds. There is concern whether exposure can result in or worsen obstructive airway diseases, but there is only limited information to assess this risk. U.S. railroad workers have been exposed to diesel exhaust since diesel locomotives were introduced after World War II, and by 1959, 95% of the locom...

A zigzag in a plane graph is a circuit of edges, such that any two, but no three, consecutive edges belong to the same face. A railroad in a plane graph is a circuit of hexagonal faces, such that any hexagon is adjacent to its neighbors on opposite edges. A graph without a railroad is called tight. We consider the zigzag and railroad structures of general 3-valent plane graph and, especially, o...

In-plant railroad engine scheduling involves routing and scheduling decisions for a heterogeneous fleet of switching engines to serve a set of time-windowand capacity-constrained transportation requests. Despite an ever-increasing competition, the current planning is purely by pencil and paper. Our paper describes the mathematical and algorithmic developments for addressing in-plant railroad de...

There are approximately 261,000 rail crossings in the United States according to the studies by the National Highway Traffic Safety Administration (NHTSA) and Federal Railroad Administration (FRA). From 1993 to 1998, there were over 25,000 highway-rail crossing incidents involving motor vehicles averaging 4,167 incidents a year. In this paper, we present a real-time computer vision system for t...