We present Chopper, a tool that efficiently explores the vast input space of file system policies to find behaviors that lead to costly performance problems. We focus specifically on block allocation, as unexpected poor layouts can lead to high tail latencies. Our approach utilizes sophisticated statistical methodologies, based on Latin Hypercube Sampling (LHS) and sensitivity analysis, to expl...

We de f i n e u n i f i c a t i o n based c o n t e x t free gr am ma r (UCFG) as a generalization of CF grammar. The shared property is the CF forrr of p r o d u c t i o n s (a s i n g l e n o n t e r m i n a l on the LHS of a rule). T h i s a l l o w s use of a p p r o p r i a t e l y m o d i f i e d C F G p a r s i n g algorithms. The HUG grammar formalism of Lauri Karttunen (paper presented...

We propose a discrete model to investigate the role of contact tracing program reducing the newcases and prevalence of tuberculosis. We observe that the tuberculosis contact tracing program has no effect on the basic reproduction number R0 but the size of social cluster has. On the other hand a contact tracing program can speed up the process of TB elimination. We compute the partial rank corre...

By two different methods, we show that LHS 4033 is an extremely massive white dwarf near its likely upper mass limit for destruction by unstable electron

This paper proposes a new image representation for texture categorization and facial analysis, relying on the use of higher-order local differential statistics as features. In contrast with models based on the global structure of textures and faces, it has been shown recently that small local pixel pattern distributions can be highly discriminative. Motivated by such works, the proposed model e...

Xinlu Li, Jinhua Yang, Liu Zhang, Shuang Li and Guang Jin 1 (School of Opt-electronics Engineering, Changchun University of Science and Technology, Changchun, 130022, China) 2 (National & Local United Engineering Research Center of Small Satellite Technology, Changchun Institute of Optics, fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China) 3 (College of Astronaut...

The release of the Hipparcos catalogue (Perryman et al. 1997) provides an opportunity to check results from asteroseismology. This has already been done for the double-mode δ Scuti star SX Phe: Høg & Petersen (1997) found excellent agreement with the parallax derived from model calculations by Petersen & Christensen-Dalsgaard (1996). Here we show that Hipparcos parallaxes for two other stars ar...