41 research outputs found
Clustering cliques for graph-based summarization of the biomedical research literature
BACKGROUND: Graph-based notions are increasingly used in biomedical data mining and knowledge discovery tasks. In this paper, we present a clique-clustering method to automatically summarize graphs of semantic predications produced from PubMed citations (titles and abstracts). RESULTS: SemRep is used to extract semantic predications from the citations returned by a PubMed search. Cliques were identified from frequently occurring predications with highly connected arguments filtered by degree centrality. Themes contained in the summary were identified with a hierarchical clustering algorithm based on common arguments shared among cliques. The validity of the clusters in the summaries produced was compared to the Silhouette-generated baseline for cohesion, separation and overall validity. The theme labels were also compared to a reference standard produced with major MeSH headings. CONCLUSIONS: For 11 topics in the testing data set, the overall validity of clusters from the system summary was 10% better than the baseline (43% versus 33%). While compared to the reference standard from MeSH headings, the results for recall, precision and F-score were 0.64, 0.65, and 0.65 respectively
Direct-write planar microultracapacitors by laser engineering
We have successfully employed laser direct write and micromachining to fabricate high capacity hydrous ruthenium oxide (RuO x H y or RuO 2 • xH 2 O) microultracapacitors. A laser direct-write process is used to deposit uniform pads of RuO 2 • 0.5H 2 O in sulfuric acid under ambient temperature and atmospheric conditions. Ultraviolet laser micromachining is used to tailor the shape and size of the deposited material into planar electrodes. The specific capacitance of the laser-deposited materials is comparable to reported values of ϳ720 F/g. The microultracapacitors demonstrate linear charge and discharge behavior at currents below 1 mA, as expected for an ideal capacitor. By studying the charge storage and power output as a function of discharge current, the power can be successfully modeled assuming only simple ohmic losses. Parallel and series combinations of these microultracapacitor cells provide the expected addition of capacitance. Maximum discharge currents of 50 mA are applied to two cells in parallel without damage to the microultracapacitor cells. The microultracapacitors exhibit high specific power and specific energy with over 1100 mW/g at approximately 9 mWhr/g for an 80 g cell with a footprint of 2 mm 2 and a thickness of 15 m