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CATS: cache-aware task scheduling for Hadoop-based systems
Springer Science + Business Media 2017 Cluster computing Vol.20 No.4
<P>Today with the explosion of big data, data-intensive cluster computing systems have driven to a new data processing paradigm. As Hadoop, one of the most famous data processing frameworks, achieves high performance by running multiple tasks in parallel across nodes in large clusters, task scheduling is considered as one of the most important factors affecting the overall performance. In modern operating systems, caching is used to improve local disk access times, providing data from the main memory without disk accesses. This option, however, is poorly utilized by existing task scheduling methods of Hadoop-based systems, mainly due to the inability of tracking cached data in shared-nothing distributed environments. In this paper, we propose a cache-aware task scheduling method, cache-aware task scheduling (CATS), for Hadoop-based systems which is able to exploit the operating system's buffer cache and assign tasks to nodes in consideration of the cached data. Through comprehensive experiments, we show that the proposed cache-aware scheduling improves the overall job execution time for various workload types and data sizes.</P>
Limb, Jin-Kyung,Jeon, Sang-Eun,Lee, Seung-Eun,Um, Ik-Hwan Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.9
Pseudo-first-order rate constants (kobs) have been determined for the nucleophilic substitution reactions of p-nitrophenyl diphenyl phosphinate (PNPDPP) with substituted phenoxides (XC6H4O - ) and butane-2,3-dione monoximate (Ox- ) in 0.1 M borate buffer (pH = 10.0) at 25.0 ${\pm}0.1^{\circ}C$. The kobs value increases sharply upon addition of cethyltrimethylammonium bromide (CTAB) to the reaction medium up to near 7 ${\times}$ 10-4 M CTAB and then decreases smoothly upon further addition of CTAB. The rate enhancement upon the addition of CTAB is most significant for the reaction with -O2CC6H4O- and least significant for the one with C6H5O- , indicating that the reactivity of these aryloxides in the presence of CTAB cannot be determined by the basicity alone. The strength of the interaction of these anionic aryloxides with the positively charged micellar aggregates has been suggested to be an important factor to determine the reactivity in the presence of CTAB. The kobs value for the reaction with Ox- increases also upon the addition of CTAB. However, the increase in the kobs value is much more significant for the reaction with Ox- than for the one with ClC6H4O- , indicating that Ox- is less strongly solvated than ClC6H4O- in H2O. The ${\alpha}-effect$ shown by Ox- in H2O has been attributed to the ground-state solvation difference between Ox- and ClC6H4O- .
Limb, J. K.,Song, D.,Jeon, M.,Han, S. Y.,Han, G.,Jhon, G. J.,Bae, Y. S.,Kim, J. WILEY 2015 JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MED Vol.9 No.4
<P>In this study we showed that 2-(sphate [(R)-TEMOSPho], a derivative of an organic chemical identified from a natural product library, promotes highly efficient differentiation of megakaryocytes. Specifically, (R)-TEMOSPho induces cell cycle arrest, cell size increase and polyploidization from K562 and HEL cells, which are used extensively to model megakaryocytic differentiation. In addition, megakaryocyte-specific cell surface markers showed a dramatic increase in expression in response to (R)-TEMOSPho treatment. Importantly, we demonstrated that such megakaryocytic differentiation can also be induced from primary human CD34(+) haematopoietic stem cells. Activation of the PI3K-AKT pathway and, to a lesser extent, the MEK-ERK pathway appears to be required for this process, as blocking with specific inhibitors interferes with the differentiation of K562 cells. A subset of (R)-TEMOSPho-treated K562 cells undergoes spontaneous apoptosis and produces platelets that are apparently functional, as they bind to fibrinogen, express P-selectin and aggregate in response to SFLLRN and AYPGFK, the activating peptides for the PAR1 and PAR4 receptors, respectively. Taken together, these results indicate that (R)-TEMOSPho will be useful for dissecting the molecular mechanisms of megakaryocytic differentiation, and that this class of compounds represents potential therapeutic reagents for thrombocytopenia. Copyright (c) 2012 John Wiley & Sons, Ltd.</P>