127 research outputs found
Search and Result Presentation in Scientific Workflow Repositories
We study the problem of searching a repository of complex hierarchical
workflows whose component modules, both composite and atomic, have been
annotated with keywords. Since keyword search does not use the graph structure
of a workflow, we develop a model of workflows using context-free bag grammars.
We then give efficient polynomial-time algorithms that, given a workflow and a
keyword query, determine whether some execution of the workflow matches the
query. Based on these algorithms we develop a search and ranking solution that
efficiently retrieves the top-k grammars from a repository. Finally, we propose
a novel result presentation method for grammars matching a keyword query, based
on representative parse-trees. The effectiveness of our approach is validated
through an extensive experimental evaluation
Answering Regular Path Queries on Workflow Provenance
This paper proposes a novel approach for efficiently evaluating regular path
queries over provenance graphs of workflows that may include recursion. The
approach assumes that an execution g of a workflow G is labeled with
query-agnostic reachability labels using an existing technique. At query time,
given g, G and a regular path query R, the approach decomposes R into a set of
subqueries R1, ..., Rk that are safe for G. For each safe subquery Ri, G is
rewritten so that, using the reachability labels of nodes in g, whether or not
there is a path which matches Ri between two nodes can be decided in constant
time. The results of each safe subquery are then composed, possibly with some
small unsafe remainder, to produce an answer to R. The approach results in an
algorithm that significantly reduces the number of subqueries k over existing
techniques by increasing their size and complexity, and that evaluates each
subquery in time bounded by its input and output size. Experimental results
demonstrate the benefit of this approach
The Factual Inconsistency Problem in Abstractive Text Summarization: A Survey
Recently, various neural encoder-decoder models pioneered by Seq2Seq
framework have been proposed to achieve the goal of generating more abstractive
summaries by learning to map input text to output text. At a high level, such
neural models can freely generate summaries without any constraint on the words
or phrases used. Moreover, their format is closer to human-edited summaries and
output is more readable and fluent. However, the neural model's abstraction
ability is a double-edged sword. A commonly observed problem with the generated
summaries is the distortion or fabrication of factual information in the
article. This inconsistency between the original text and the summary has
caused various concerns over its applicability, and the previous evaluation
methods of text summarization are not suitable for this issue. In response to
the above problems, the current research direction is predominantly divided
into two categories, one is to design fact-aware evaluation metrics to select
outputs without factual inconsistency errors, and the other is to develop new
summarization systems towards factual consistency. In this survey, we focus on
presenting a comprehensive review of these fact-specific evaluation methods and
text summarization models.Comment: 9 pages, 5 figure
Parallel implementation of 3D global MHD simulations for Earth’s magnetosphere
AbstractThis paper presents a dynamic domain decomposition (D3) technique for implementing the parallelization of the piecewise parabolic method (PPM) for solving the ideal magnetohydrodynamics (MHD) equations. The key point of D3 is distributing the work dynamically among processes during the execution of the PPM algorithm. This parallel code utilizes D3 with a message passing interface (MPI) in order to permit efficient implementation on clusters of distributed memory machines and may also simultaneously exploit threading for multiprocessing shared address space architectures. 3D global MHD simulation results for the Earth’s magnetosphere on the massively parallel supercomputers Deepcomp 1800 and 6800 demonstrate the scalability and efficiency of our parallelization strategy
Search and Result Presentation in Scientific Workflow Repositories
We study the problem of searching a repository of complex hierarchical workflows whose component modules, both composite and atomic, have been annotated with keywords. Since keyword search does not use the graph structure of a workflow, we develop a model of workflows using context-free bag grammars. We then give efficient polynomial-time algorithms that, given a workflow and a keyword query, determine whether some execution of the workflow matches the query. Based on these algorithms we develop a search and ranking solution that efficiently retrieves the top-k grammars from a repository. Finally, we propose a novel result presentation method for grammars matching a keyword query, based on representative parse-trees. The effectiveness of ou
Retracted: Safranal induces autophagy by AMPK activation and protects neurons against amyloid beta in Alzheimer’s disease
This article has been retracted by the authors
An innovative micromechanics-based three-dimensional long-term strength criterion for fracture assessment of rock materials
Rocks may exhibit time-dependent behaviors. Long-term strength criterion significantly dominates creep failure of rocks. Rocks contain many microcracks, which lead to degrade of long-term strength. In this paper, it is assumed that there exist three-dimensional penny-shaped microcracks in rocks. The mode II stress intensity factors at tips of three-dimensional penny-shaped microcracks in Burgers viscoelastic rock matrix is derived. A novel micromechanics-based three-dimensional long-term strength criterion is established to consider the effects of time and the intermediate principal stress on creep failure of rocks. By comparison with the previous experimental data, it is found that the novel micromechanics-based three-dimensional long-term strength criterion is in good agreement with the experimental data
Novel sulfamoylamino-containing cephalosporin derivatives, and their in vitro antibacterial properties
Purpose: To prepare and develop new antibacterial agents with novel molecular structures.
Method: A series of novel sulfamoylamino-containing cephalosporin derivatives were synthesized. The in vitro antibacterial effects of the derivatives against Gram-positive bacteria (S. aureus, S. pneumonia and S. epidermidis), and Gram-negative bacteria (E. coli, P. aeruginosa, and K. pneumonia) were investigated.
Results: Compounds 13a and 13b exhibited excellent antibacterial effects against all the Gram-positive and Gram-negative bacteria tested, when compared with other cephalosporin derivatives.
Conclusion: Of these new cephalosporin derivatives, compounds 13a and 13b show the most potent antibacterial activity and would need to be further investigated
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