Exploratory analysis of textual data streams

In this paper, we address exploratory analysis of textual data streams and we propose a bootstrapping process based on a combination of keyword similarity and clustering techniques to: (i) classify documents into fine-grained similarity clusters, based on keyword commonalities; (ii) aggregate similar clusters into larger document collections sharing a richer, more user-prominent keyword set that we call topic; (iii) assimilate newly extracted topics of current bootstrapping cycle with existing topics resulting from previous bootstrapping cycles, by linking similar topics of different time periods, if any, to highlight topic trends and evolution. An analysis framework is also defined enabling the topic-based exploration of the underlying textual data stream according to a thematic perspective and a temporal perspective. The bootstrapping process is evaluated on a real data stream of about 330.000 newspaper articles about politics published by the New York Times from Jan 1st 1900 to Dec 31st 2015

Democracy, Technology and The Civil Rights Project

Democracy has been defined as a political system in which the whole people make, and are entitled to make, the basic determining decisions on important matters of public policy. While the United States is often touted as the world\u27s leading proponent of democracy, many U.S. citizens find themselves unable to engage in one of the central acts of democracy—creating public voice through public engagement. Public engagement in the United States is constrained by our inability to talk through our shared, complementary and divergent values. This lack of public engagement and our inability to speak in a public voice is also driven by a cultural tendency to reduce complex public issues to simple for or against policy positions. The process of building a public voice in the United States is further complicated by the vast racial, ethnic, linguistic and economic diversity, and the imbalance of power that exist among these separate sectors of our society. The history of this country is replete with the struggles of people to overcome these power imbalances and create opportunities for their voices to become an integral part of the public voice. But, as the 21st century approaches, these same citizens find themselves on the brink of a new battle over citizen participation. This battle is being defined around access to and use of technology. Currently, most Americans are merely bystanders watching the rapid advances in technology shift the political, economic, and social terrain in which their viability as citizens is being determined. For members of the African-American community, and indeed for all communities of color and for economically disadvantaged communities, their ability to participate as equal citizens will now, in part, depend upon their ability to shape the technological world that is redefining the concept of public discourse and public involvement in the political process

Model checker execution reports

Software model checking constitutes an undecidable problem and, as such, even an ideal tool will in some cases fail to give a conclusive answer. In practice, software model checkers fail often and usually do not provide any information on what was effectively checked. The purpose of this work is to provide a conceptual framing to extend software model checkers in a way that allows users to access information about incomplete checks. We characterize the information that model checkers themselves can provide, in terms of analyzed traces, i.e. sequences of statements, and safe canes, and present the notion of execution reports (ERs), which we also formalize. We instantiate these concepts for a family of techniques based on Abstract Reachability Trees and implement the approach using the software model checker CPAchecker. We evaluate our approach empirically and provide examples to illustrate the ERs produced and the information that can be extracted

Semantic Self-Formation of Communities of Peers

The formation of semantic communities of peers plays a crucial role for realizing effective query propagation mechanisms on a semantic basis. In this paper, we propose a novel approach to the self-organization of autonomous communities of peers; we propose semantic handshake techniques based on semantic community aggregation and community-aware query propagation techniques exploiting dynamic ontology matching techniques for improving traditional P2P search and discovery capabilities

Switching of +/-360deg domain wall states in a nanoring by an azimuthal Oersted field

We demonstrate magnetic switching between two $360^\circ$ domain wall vortex states in cobalt nanorings, which are candidate magnetic states for robust and low power MRAM devices. These $360^\circ$ domain wall (DW) or "twisted onion" states can have clockwise or counterclockwise circulation, the two states for data storage. Reliable switching between the states is necessary for any realistic device. We accomplish this switching by applying a circular Oersted field created by passing current through a metal atomic force microscope tip placed at the center of the ring. After initializing in an onion state, we rotate the DWs to one side of the ring by passing a current through the center, and can switch between the two twisted states by reversing the current, causing the DWs to split and meet again on the opposite side of the ring. A larger current will annihilate the DWs and create a perfect vortex state in the rings.Comment: 5 pages, 5 figure

Metric Learning to Enhance Hyperspectral Image Segmentation

Unsupervised hyperspectral image segmentation can reveal spatial trends that show the physical structure of the scene to an analyst. They highlight borders and reveal areas of homogeneity and change. Segmentations are independently helpful for object recognition, and assist with automated production of symbolic maps. Additionally, a good segmentation can dramatically reduce the number of effective spectra in an image, enabling analyses that would otherwise be computationally prohibitive. Specifically, using an over-segmentation of the image instead of individual pixels can reduce noise and potentially improve the results of statistical post-analysis. In this innovation, a metric learning approach is presented to improve the performance of unsupervised hyperspectral image segmentation. The prototype demonstrations attempt a superpixel segmentation in which the image is conservatively over-segmented; that is, the single surface features may be split into multiple segments, but each individual segment, or superpixel, is ensured to have homogenous mineralogy

Westerbork Ultra-Deep Survey of HI at z=0.2

In this contribution, we present some preliminary observational results from the completed ultra-deep survey of 21cm emission from neutral hydrogen at redshifts z=0.164-0.224 with the Westerbork Synthesis Radio Telescope. In two separate fields, a total of 160 individual galaxies has been detected in neutral hydrogen, with HI masses varying from 1.1x10^9 to 4.0x10^10 Msun. The largest galaxies are spatially resolved by the synthesized beam of 23x37 arcsec^2 while the velocity resolution of 19 km/s allowed the HI emission lines to be well resolved. The large scale structure in the surveyed volume is traced well in HI, apart from the highest density regions like the cores of galaxy clusters. All significant HI detections have obvious or plausible optical counterparts which are usually blue late-type galaxies that are UV-bright. One of the observed fields contains a massive Butcher-Oemler cluster but none of the associated blue galaxies has been detected in HI. The data suggest that the lower-luminosity galaxies at z=0.2 are more gas-rich than galaxies of similar luminosities at z=0, pending a careful analysis of the completeness near the detection limit. Optical counterparts of the HI detected galaxies are mostly located in the 'blue cloud' of the galaxy population although several galaxies on the 'red sequence' are also detected in HI. These results hold great promise for future deep 21cm surveys of neutral hydrogen with MeerKAT, APERTIF, ASKAP, and ultimately the Square Kilometre Array.Comment: 10 pages, 9 figures, Proceedings of ISKAF2010 Science Meeting: A New Golden Age for Radio Astronomy, June 10-14 2010, Assen, the Netherlands. Edited by J. van Leeuwen. Movies of rendered rotating data cubes are available at http://www.astro.rug.nl/~verheyen/BUDHIES/index.htm