10,774 research outputs found
An acoustic investigation of the Cantonese vowels in the speech of the adult and child speakers
Abstract no. 2aSC25published_or_final_versio
The articulatory and acoustical characteristics of the "apical vowels" in Beijing Mandarin
Abstract no. 4pSC23published_or_final_versio
Processing SPARQL queries with regular expressions in RDF databases
Background: As the Resource Description Framework (RDF) data model is widely used for modeling and sharing a lot of online bioinformatics resources such as Uniprot (dev.isb-sib.ch/projects/uniprot-rdf) or Bio2RDF (bio2rdf.org), SPARQL - a W3C recommendation query for RDF databases - has become an important query language for querying the bioinformatics knowledge bases. Moreover, due to the diversity of users' requests for extracting information from the RDF data as well as the lack of users' knowledge about the exact value of each fact in the RDF databases, it is desirable to use the SPARQL query with regular expression patterns for querying the RDF data. To the best of our knowledge, there is currently no work that efficiently supports regular expression processing in SPARQL over RDF databases. Most of the existing techniques for processing regular expressions are designed for querying a text corpus, or only for supporting the matching over the paths in an RDF graph.
Results: In this paper, we propose a novel framework for supporting regular expression processing in SPARQL query. Our contributions can be summarized as follows. 1) We propose an efficient framework for processing SPARQL queries with regular expression patterns in RDF databases. 2) We propose a cost model in order to adapt the proposed framework in the existing query optimizers. 3) We build a prototype for the proposed framework in C++ and conduct extensive experiments demonstrating the efficiency and effectiveness of our technique.
Conclusions: Experiments with a full-blown RDF engine show that our framework outperforms the existing ones by up to two orders of magnitude in processing SPARQL queries with regular expression patterns.X113sciescopu
Site-2 protease responds to oxidative stress and regulates oxidative injury in mammalian cells
published_or_final_versio
Clustering uncertain data using voronoi diagrams and R-tree index
We study the problem of clustering uncertain objects whose locations are described by probability density functions (pdfs). We show that the UK-means algorithm, which generalizes the k-means algorithm to handle uncertain objects, is very inefficient. The inefficiency comes from the fact that UK-means computes expected distances (EDs) between objects and cluster representatives. For arbitrary pdfs, expected distances are computed by numerical integrations, which are costly operations. We propose pruning techniques that are based on Voronoi diagrams to reduce the number of expected distance calculations. These techniques are analytically proven to be more effective than the basic bounding-box-based technique previously known in the literature. We then introduce an R-tree index to organize the uncertain objects so as to reduce pruning overheads. We conduct experiments to evaluate the effectiveness of our novel techniques. We show that our techniques are additive and, when used in combination, significantly outperform previously known methods. © 2006 IEEE.published_or_final_versio
Multi-pulse addressing of a Raman quantum memory: configurable beam splitting and efficient readout
Quantum memories are vital to the scalability of photonic quantum information
processing (PQIP), since the storage of photons enables repeat-until-success
strategies. On the other hand the key element of all PQIP architectures is the
beam splitter, which allows to coherently couple optical modes. Here we show
how to combine these crucial functionalities by addressing a Raman quantum
memory with multiple control pulses. The result is a coherent optical storage
device with an extremely large time-bandwidth product, that functions as an
array of dynamically configurable beam splitters, and that can be read out with
arbitrarily high efficiency. Networks of such devices would allow fully
scalable PQIP, with applications in quantum computation, long-distance quantum
communications and quantum metrology.Comment: 4 pages, 3 figure
Final report of the Construction Industry Institute, Hong Kong research project on reinventing the Hong Kong construction industry for its sustainable development
Author name used in this publication: Andrew N. BaldwinAuthor name used in this publication: Y. H. ChiangAuthor name used in this publication: Joyce W. S. CheungAuthor name used in this publication: Joanne W. S. NgConstruction Industry Institute-Hong Kong Report, no. 132008-2009 > Academic research: not refereed > Research book or monograph (author)Other Versio
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Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study.
BackgroundExisting evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients.Patients and methodsChemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain.ResultsNinety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022).ConclusionsWhile elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes
Surface Oxide Formation during Rapid Heating of Zn-coated Press Hardening Steel
During the conventional die-quenching processing of a galvanized PHS steel, a thick ZnO layer is formed at the surface. When the heating rate is increased, the oxide at the surface is a thin Al2O3 layer. This remarkable change in surface oxide during rapid heating is due to the partial melting of the coating instead of the solidification of the coating and the formation of Fe-Zn intermetallics. In the present study, the characterization of the surface oxide formation at different heating rates is presented.X1184Ysciescopu
Thermoelectric properties of Al-doped mesoporous ZnO thin films
Al-doped mesoporous ZnO thin films were synthesized by a sol-gel process and an evaporation-induced self-assembly process. In this work, the effects of Al doping concentration on the electrical conductivity and characterization of mesoporous ZnO thin films were investigated. By changing the Al doping concentration, ZnO grain growth is inhibited, and the mesoporous structure of ZnO is maintained during a relatively high temperature annealing process. The porosity of Al-doped mesoporous ZnO thin films increased slightly with increasing Al doping concentration. Finally, as electrical conductivity was increased as electrons were freed and pore structure was maintained by inhibiting grain growth, the thermoelectric property was enhanced with increasing Al concentration. © 2013 Min-Hee Hong et al
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