Matthew McGill

Learn More
A large class of diagrams can be informally characterized as node – link diagrams. Typically nodes represent entities, and links represent relationships between them. The discipline of graph drawing is concerned with methods for drawing abstract versions of such diagrams. At the foundation of the discipline are a set of graph aesthetics (rules for graph(More)
Many existing automatic graph layout algorithms are unrelated to any particular semantic domain. Designers of such algorithms tend to conform to layout aesthetics, and claim that by doing so, the resultant diagram is easy to understand. Few algorithms are designed for a specific domain, and there is no guarantee that the aesthetics used for generic layout(More)
Despite UML being considered a software engineering standard, the UML syntactic notations used in texts, papers, documentation and CASE tools are often different. The decision as to which of the semantically equivalent notational variations to use appears to be according to the personal preference of the author or publisher, rather than based on any(More)
An empirical relationship is derived between the multiple-scattering fraction and the linear depolarization ratio by using Monte Carlo simulations of water clouds measured by backscatter lidar. This relationship is shown to hold for clouds having a wide range of extinction coefficients, mean droplet sizes, and droplet size distribution widths. The(More)
[1] A technique to classify ice particles into different shape categories, based on lidar depolarization ratio, is considered. This technique is applied to observations taken during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL-FACE) campaign with the airborne Cloud Physics Lidar. The retrieved(More)
Well-defined symbolic notations are essential for communication between teams of people working on any application. For large software implementations, UML is commonly used; for databases, entity-relationship diagrams are useful. However, the form of notation used in texts, papers, and documentation and learning materials is often different, and tends to(More)
Many applications for robotics require that the robot know its current position in the environment. While there exist several solutions for localizing a robot, even in a previously unknown environment, they often require an estimate of the robot's motion. However, in many situations, a robot may not have motion encoders, or its encoders may be highly(More)
Search and rescue robots are intended to work as aids to human rescuers. One of the research challenges is how to combine autonomous operation with operator control. This paper presents a single software system which independently operates several physically distinct robots. One operator can coordinate several robots by switching their individual mode(More)
Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically(More)