572 search results - page 70 / 115 » Exponential-Time Approximation of Hard Problems |
PODS
2004
ACM
15 years 10 months ago
2004
ACM
We study the problem of answering queries over sources with limited access patterns. Given a first-order query Q, the problem is to decide whether there is an equivalent query whi...
IGARSS
2009
14 years 7 months ago
2009
Finding an accurate sparse approximation of a spectral vector described by a linear model, when there is available a library of possible constituent signals (called endmembers or ...
SIGMOD
2012
ACM
13 years 16 days ago
2012
ACM
Query substitution is an important problem in information retrieval. Much work focuses on how to find substitutes for any given query. In this paper, we study how to efficiently ...
STOC
2005
ACM
15 years 10 months ago
2005
ACM
A low-distortion embedding between two metric spaces is a mapping which preserves the distances between each pair of points, up to a small factor called distortion. Low-distortion...
WISEC
2009
ACM
15 years 4 months ago
2009
ACM
Time synchronization in highly distributed wireless systems like sensor and ad hoc networks is extremely important in order to maintain a consistent notion of time throughout the ...