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This paper describes the use of Storm at Twitter. Storm is a real-time fault-tolerant and distributed stream data processing system. Storm is currently being used to run various critical computations in Twitter at scale, and in real-time. This paper describes the architecture of Storm and its methods for distributed scale-out and fault-tolerance. This paper(More)
Sybil attacks are becoming increasingly widespread, and pose a significant threat to online social systems; a single adversary can inject multiple colluding identities in the system to compromise security and privacy. Recent works have leveraged the use of social network-based trust relationships to defend against Sybil attacks. However , existing defenses(More)
Storm has long served as the main platform for real-time analytics at Twitter. However, as the scale of data being processed in real-time at Twitter has increased, along with an increase in the diversity and the number of use cases, many limitations of Storm have become apparent. We need a system that scales better, has better debug-ability, has better(More)
We describe MW – a software framework that allows users to quickly and easily parallelize scientific computations using the master-worker paradigm on the computational grid. MW provides both a " top level " interface to application software and a " bottom level " interface to existing grid computing toolkits. Both interfaces are briefly described. We(More)
This paper compares two separately developed systems for monitoring activities related to business contracts, describes how we integrated them and exploits the lessons learned from this process to identify a core set of requirements for a Business Contract Language (BCL). Concepts in BCL needed for contract monitoring include: the expression of coordinated(More)
The goal of this work is to create a tool that allows users to easily distribute large scientific computations on computational grids. Our tool MW relies on the simple master–worker paradigm. MW provides both a top Level interface to application software and a bottom Level interface to existing Grid computing toolkits. Both interfaces are briefly described.(More)
The Burrows-Wheeler transform is a block-sorting algorithm which has been shown empirically to be useful in compressing text data. In this paper we study the output distribution of the transform for i.i.d. sources, tree sources and stationary ergodic sources. We can also give analytic bounds on the performance of some universal compression schemes which use(More)
Background: Although the coordinated sequence of hormonal changes during the normal menstrual cycle are well characterized, whether similar or parallel changes occur in the distribution of various electrolytes has not been clearly established. Materials and methods: This corollary follow up study on 50 healthy normal menstruating females presents variation(More)
A major challenge in the formulation of optimization models for large-scale, complex operational problems is that some data are impossible or uneconomical to collect, producing a cost model that suffers from incomplete information. As a result, even an optimal solution may be " wrong " in the sense that it is solving the wrong problem. In many operational(More)