Theory and Techniques for Synthesizing a Family of Graph Algorithms

Although Breadth-First Search (BFS) has several advantages over Depth-First Search (DFS) its prohibitive space requirements have meant that algorithm designers often pass it over in favor of DFS. To address this shortcoming, we introduce a theory of Efficient BFS (EBFS) along with a simple recursive program schema for carrying out the search. The theory is based on dominance relations, a long standing technique from the field of search algorithms. We show how the theory can be used to systematically derive solutions to two graph algorithms, namely the Single Source Shortest Path problem and the Minimum Spanning Tree problem. The solutions are found by making small systematic changes to the derivation, revealing the connections between the two problems which are often obscured in textbook presentations of them.Comment: In Proceedings SYNT 2012, arXiv:1207.055

Recovering facial shape using a statistical model of surface normal direction

In this paper, we show how a statistical model of facial shape can be embedded within a shape-from-shading algorithm. We describe how facial shape can be captured using a statistical model of variations in surface normal direction. To construct this model, we make use of the azimuthal equidistant projection to map the distribution of surface normals from the polar representation on a unit sphere to Cartesian points on a local tangent plane. The distribution of surface normal directions is captured using the covariance matrix for the projected point positions. The eigenvectors of the covariance matrix define the modes of shape-variation in the fields of transformed surface normals. We show how this model can be trained using surface normal data acquired from range images and how to fit the model to intensity images of faces using constraints on the surface normal direction provided by Lambert's law. We demonstrate that the combination of a global statistical constraint and local irradiance constraint yields an efficient and accurate approach to facial shape recovery and is capable of recovering fine local surface details. We assess the accuracy of the technique on a variety of images with ground truth and real-world images

An investigation of the role of current and future remote sensing data systems in numerical meteorology

A flexible system for performing observing system simulation experiments which made contributions to meteorology across all elements of the observing system simulation experiment (OSSE) components was developed. Future work will seek better understanding of the links between satellite-measured radiation and radiative transfer in the clear, cloudy and precipitating atmosphere and investigate how that understanding might be applied to improve the depiction of the initial state and the treatment of physical processes in forecast models of the atmosphere

Gauss\u27 hypergeometric equation

As early as the seventeenth century the English mathematician, john Wallis (1616-1703), used the term hypergeometric to describe a series which he was studying. This series, ∑(a)(a+b)(a+2b)…(a+n-1b), is quite different from the usual geometric series, hence the term, hyper (=above) plus geometric, was used to signify that the series was of greater complexity than the geometric series. Wallis did not consider his series a power series or a function of x. In 1769 this series received a remarkable development at the hands of Loonhard Euler who, following the example of Wallis, applied the word hypergeometric to it. He observed that the series is dependent upon the integration of a linear partial differtial equation of the second order. In his work the series is treated from three distinct standpoint: (i) as a power series, (ii) as an integral of a certain linear equation of the second order, (iii) and as a definite integral.

Vital Sign Ontology

We introduce the Vital Sign Ontology (VSO), an extension of the Ontology for General Medical Science (OGMS) that covers the consensus human vital signs: blood pressure, body temperature, respiratory rate, and pulse rate. VSO provides a controlled structured vocabulary for describing vital sign measurement data, the processes of measuring vital signs, and the anatomical entities participating in such measurements. VSO is implemented in OWL-DL and follows OBO Foundry guidelines and best practices. If properly developed and extended, we believe the VSO will find applications for the EMR, clinical informatics, and medical device communities

Can Electronic Reverse-Auctions Destroy Business Relationships?

The fast-paced world of business in the early twenty-first century has created ever decreasing time periods between the waves of cycles. This phenomenon can lead to dramatic changes in prevailing practices in very short periods of time. In fact, it almost appears that management thought leaders are in direct conflict in some situations. Such a shift has occurred in recent years in terms of thoughts about the relationships between business buyers and sellers. Japanese businesses lead the movement towards trust-based relationships becoming sole-source arrangements in the 1980s. Management gurus worldwide were applauding this practice. By the late 1990s the antithesis was occurring as thought leaders began advocating not only the avoidance of sole-sourcing but the use of what could be viewed as a practice that made long-term relationships between buyers and sellers impossible. This was the dawning of the era of the electronic reverse auction. Is this a good thing or a curse