Artyom Sharov

GridBot: execution of bags of tasks in multiple grids

We present a holistic approach for efficient execution of bags-of-tasks (BOTs) on multiple grids, clusters, and volunteer computing grids virtualized as a single computing platform. The challenge is twofold: to assemble this compound environment and to employ it for execution of a mixture of throughput- and performance-oriented BOTs, with a dozen to millions of tasks each. Our generic mechanism allows per BOT specification of dynamic arbitrary scheduling and replication policies as a function of the system state, BOT execution state, and BOT priority. We implement our mechanism in the GridBot system and demonstrate its capabilities in a production setup. GridBot has executed hundreds of BOTs with over 9 million jobs during three months alone; these have been invoked on 25,000 hosts, 15,000 from the Superlink@Technion community grid and the rest from the Technion campus grid, local clusters, the Open Science Grid, EGEE, and the UW Madison pool.

Constructing polar codes for non-binary alphabets and MACs

Consider a channel with an input alphabet that is finite but not necessarily binary. A method for approximating such a channel having a large output alphabet size by a degraded version of it having a smaller output alphabet size is presented and analyzed. The approximation method is used to construct polar codes for both single-user and multiple-access channels with prime input alphabet sizes.

Two-Dimensional Constrained Coding Based on Tiling

A new variable-rate coding technique is presented for two-dimensional (2-D) constraints. For certain constraints, such as the (0, 2)-runlength-limited (RLL) and (3,?)-RLL constraints, the technique is shown to improve on previously published lower bounds on the capacity of the constraint.

Two-dimensional constrained coding based on tiling

A new variable-rate coding technique is presented for two-dimensional (2-D) constraints. For certain constraints, such as the (0, 2)-runlength-limited (RLL) and (3,¿)-RLL constraints, the technique is shown to improve on previously published lower bounds on the capacity of the constraint.

Improved bounds and constructions for granular media coding

Improved bounds on the rates of grain-correcting codes are presented. The lower bounds are Gilbert-Varshamov-like ones combined with a construction by Gabrys et al.; additionally, two asymptotically equivalent upper bounds are presented. Both the lower and the upper bounds improve on the previously known results for certain ranges of parameters. Constructions of 1-grain-correcting codes which are based on a partitioning technique are presented for lengths up to 18.

Fixed-rate tiling encoders for 2-D constraints

A new fixed-rate tiling-based coding scheme is presented for two-dimensional (2-D) constraints. The new scheme is shown to improve on the best known rates of formerly published fixed-rate encoders for certain constraints, such as the “no isolated bits” constraint and several 2-D runlength limited (RLL) constraints. Methods of efficient implementation of the suggested scheme are discussed.

On the Capacity of Generalized Ising Channels

Nearly tight lower and upper bounds on the capacity of generalized Ising channels are presented. For the case where feedback is allowed, a closed-form expression for the capacity is found for channel error probability

Automatic Reconfiguration of Distributed Storage

p\in [{0, p_{0}}]

New upper bounds for grain-correcting and grain-detecting codes.

, where

Short paper: Materializing Highly Available Grids

p_{0}\approx 0.398324