The textbook first encounter with nonlinearity in a partial differential equation (PDE) is the first-order wave equation: ut + uux = 0. Often referred to as the inviscid Burgers equation, many are familiar with this equation in the theoretical contexts of characteristics, wavebreaking, or shock propagation. Another canonical behavior contained within this simplest of PDEs is the spectral cascad...

In this paper we address the problem of scalability in temporal reasoning. In particular, new algorithms for efficiently managing large sets of relations in the Point Algebra are provided. Our representation of time is based on timegraphs, graphs partitioned into a set of chains on which the search is supported by a rnetagraph data structure. The approach is an extension of the time representat...

The representation of music structures is, from Musicology to Artificial Intelligence, a widely known research focus. It entails several generic Knowledge Representation problems like structured knowledge representation, time representation and causality. In this paper, we focus the problem of representing and reasoning about time in the framework of a structured music representation approach, ...

The Therapeutic Abortion Survey was originally designed to measure all legally induced abortions performed in Canada (and to the extent possible, abortions performed in the US on Canadian residents prior to 2004). Statistics Canada was responsible for the survey up to the 1994 data year. As of the 1995 data year, the Canadian Institute for Health Information (CIHI) assumed data collection, comp...

1 Cardiovascular Center, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, Estados Unidos Correspondência para: Mazen Albaghdadi, MD, Research Fellow, Carver College of Medicine, University of Iowa, 1216 Medical Education Research Facility, Iowa City, IA, USA – 52242-2600 – E-mail: [email protected] Recebido: 27/8/2007 Aceito: 25/9/2007 ABS...

We address the problem of recognizing American Football plays in video. In contrast to recent work on activity recognition this is a much more challenging problem as it involves the actions of multiple players. We propose a method which builds on recent advances in activity recognition, such as using shape and motion based spatio-temporal features and building a space-time representation of the...

This paper addresses the problems related to data types used for time representation in DEVS, a formalism for the specification and simulation of discrete-event systems. When evaluating a DEVS simulation model into an actual computer simulation program, a data type is required to hold the virtual time of the simulation and the time elapsed in the model of the simulated system. We review the com...

Even with much activity over the past decade, including organized efforts on both sides of the Atlantic, the representation of both space and time in digital databases is still problematic and functional space-time systems have not gone beyond the limited prototype stage. Why is this the case? Why did it take twenty years from the ®rst GIS for the for representation and analysis in the temporal...

The problem addressed in this work is to develop a comprehensive mathematical programming model for the efficient scheduling of oil-refinery operations. Our approach is first to decompose the overall problem spatially into three domains: the crude-oil unloading and blending, the production unit operations and the product blending and delivery. In particular, the first problem involves the crude...

A novel technique of analysis of an arbitrary primary time series into a set of secondary, timelimited, local, constituent time series, the TT-transform, is presented. The time–time representation is derived from the S-transform, a method of representation of a real time series as a set of complex, time-localized spectra. When integrated over time, the S-transform becomes the Fourier transform ...