Active Semi-Supervised Learning Using Sampling Theory for Graph Signals

We consider the problem of offline, pool-based active semi-supervised learning on graphs. This problem is important when the labeled data is scarce and expensive whereas unlabeled data is easily available. The data points are represented by the vertices of an undirected graph with the similarity between them captured by the edge weights. Given a target number of nodes to label, the goal is to choose those nodes that are most informative and then predict the unknown labels. We propose a novel framework for this problem based on our recent results on sampling theory for graph signals. A graph signal is a real-valued function defined on each node of the graph. A notion of frequency for such signals can be defined using the spectrum of the graph Laplacian matrix. The sampling theory for graph signals aims to extend the traditional Nyquist-Shannon sampling theory by allowing us to identify the class of graph signals that can be reconstructed from their values on a subset of vertices. This approach allows us to define a criterion for active learning based on sampling set selection which aims at maximizing the frequency of the signals that can be reconstructed from their samples on the set. Experiments show the effectiveness of our method.Comment: 10 pages, 6 figures, To appear in KDD'1

Exploring Emotions Using Invasive Methods: Review of 60 Years of Human Intracranial Electrophysiology

Over the past 60 years, human intracranial electrophysiology (HIE) has been used to characterize seizures in patients with epilepsy. Secondary to the clinical objectives, electrodes implanted intracranially have been used to investigate mechanisms of human cognition. In addition to studies of memory and language, HIE methods have been used to investigate emotions. The aim of this review is to outline the contribution of HIE (electrocorticography, single-unit recording and electrical brain stimulation) to our understanding of the neural representations of emotions. We identified 64 papers dating back to the mid-1950s which used HIE techniques to study emotional states. Evidence from HIE studies supports the existence of widely distributed networks in the neocortex, limbic/paralimbic regions and subcortical nuclei which contribute to the representation of emotional states. In addition, evidence from HIE supports hemispheric dominance for emotional valence. Furthermore, evidence from HIE supports the existence of overlapping neural areas for emotion perception, experience and expression. Lastly, HIE provides unique insights into the temporal dynamics of neural activation during perception, experience and expression of emotional states. In conclusion, we propose that HIE techniques offer important evidence which must be incorporated into our current models of emotion representation in the human brain

Crew and Thermal Systems Strategic Communications Initiatives in Support of NASA's Strategic Goals

NASA has defined strategic goals to invest in next-generation technologies and innovations, inspire students to become the future leaders of space exploration, and expand partnerships with industry and academia around the world. The Crew and Thermal Systems Division (CTSD) at the NASA Johnson Space Center actively supports these NASA initiatives. In July 2011, CTSD created a strategic communications team to communicate CTSD capabilities, technologies, and personnel to external technical audiences for business development and collaborative initiatives, and to students, educators, and the general public for education and public outreach efforts. This paper summarizes the CTSD Strategic Communications efforts and metrics through the first half of fiscal year 2012 with projections for end of fiscal year data

Extravehicular Activity Systems Education and Public Outreach in Support of NASA's STEM Initiatives in Fiscal Year 2011

NASA's goals to send humans beyond low Earth orbit will involve the need for a strong engineering workforce. Research indicates that student interest in science, technology, engineering, and math (STEM) areas is on the decline. According to the Department of Education, the United States President has mandated that 100,000 educators be trained in STEM over the next decade to reduce this trend. NASA has aligned its Education and Public Outreach (EPO) initiatives to include emphasis in promoting STEM. The Extravehicular Activity (EVA) Systems Project Office at the NASA Johnson Space Center actively supports this NASA initiative by providing subject matter experts and hands-on, interactive presentations to educate students, educators, and the general public about the design challenges encountered as NASA develops EVA hardware for exploration missions. This paper summarizes the EVA Systems EPO efforts and metrics from fiscal year 2011

MAMS data for the Convection and Moisture Experiment (CAMEX)

During the fall of 1993, NASA sponsored a field program called the Convection And Moisture Experiment (CAMEX). The field effort focused on: convective storms in order to investigate their associated electrical properties, precipitation, and predictability, and atmospheric moisture studies. The data collected from the Multispectral Atmospheric Mapping Sensor (MAMS) onboard a NASA ER-2 aircraft which was deployed out of NASA/Wallops Flight Facility, Wallops Island, Virginia, from 11 Sep. through 7 Oct., 1993, is described

Molecular and morphological analyses confirm that all loons (Aves: Gaviiformes) form a single holobaramin

Loons or divers (Aves: Gaviiformes), a group of waterbirds found primarily in the Northern Hemisphere, are comprised of several extinct taxa as well as an extant family (Gaviidae) with one genus (Gavia) and five species. Recent phylogenetic studies suggest that the Sphenisciformes (penguins) and Procellariiformes (petrels, albatrosses, and shearwaters) form a sister group to the loons. Our previous research, based on hybridization, morphological, and vocalization data, found that all extant loons form a single holobaramin (i.e., created kind). This previous study, however, was inconclusive as to the membership of fossil taxa within the kind. The goal of the present study is to verify the baraminic status of the extant loons using new molecular baraminology techniques and to further evaluate extinct loon morphology to determine whether they also belong to the loon holobaramin. DNA sequences from four mitochondrial genes (CO1, CYTB, NADH1, and NADH2) were gathered, for all extant loons and several outgroups, from the BOLD and GenBank databases and aligned with ClustalW in MEGA. Corrected distance matrices were created with the TN93 + Gamma model and analyzed using hierarchical clustering, classic multidimensional scaling, and medoid partitioning in R software. A newly published dataset of skeletal characters, from extinct and extant loons as well as several outgroups, was also analyzed using statistical baraminology clustering methods (BARCLAY: DCA, MDS, PAM, FANNY). Extant loons consistently formed significant/separate clusters across all genes and molecular analyses, confirming they share significant continuity with one another and significant discontinuity from the outgroups. Morphological analyses demonstrated that all loons, extant and extinct, were positively associated/correlated with one another, sharing significant continuity, and negatively associated/correlated, displaying significant discontinuity, with several key avian outgroups. Based on considerable evidence of both continuity among loon species and discontinuity from other avian groups (including the supposed sister groups, Sphenisciformes and Procellariiformes), we conclude that all loons (Aves: Gaviiformes), both extant and extinct species, form a single holobaramin. These results are consistent with our previous research and Answers in Genesis’s brief analysis of loon hybridization for their Ark Encounter Project

Operations summary for the convection and moisture experiment (CAMEX)

During the fall of 1993, NASA sponsored a field program called the Convection and Moisture Experiment (CAMEX) at Wallops Island, Virginia. CAMEX was a multidisciplinary experiment design to measure the three dimensional moisture fields over Wallops Island and to characterize the multifrequency radiometric signature of tropical convection over the Gulf Stream and southeastern Atlantic Ocean. This document summarizes the daily CAMEX activities, including ground and aircraft (NASA ER-2) operations, and includes 'quick-look' summaries of data acquisition along with data examples provided by the various CAMEX PI's