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MODIST is the first model checker designed for transparently checking unmodified distributed systems running on unmodified operating systems. It achieves this transparency via a novel architecture: a thin interposition layer exposes all actions in a distributed system and a centralized, OS-independent model checking engine explores these actions(More)
Peer-to-peer networks often use incentive policies to encourage cooperation between nodes. Such systems are generally susceptible to collusion by groups of users in order to gain unfair advantages over others. While techniques have been proposed to combat Web spam collusion, there are few measurements of real collusion in deployed systems. In this paper, we(More)
<i>Batched stream processing</i> is a new distributed data processing paradigm that models recurring batch computations on incrementally bulk-appended data streams. The model is inspired by our empirical study on a trace from a large-scale production data-processing cluster; it allows a set of effective query optimizations that are not possible in a(More)
As the study of large graphs over hundreds of gigabytes becomes increasingly popular for various data-intensive applications in cloud computing, developing large graph processing systems has become a hot and fruitful research area. Many of those existing systems support a <i>vertex-oriented</i> execution model and allow users to develop custom logics on(More)
Standard state-machine replication involves consensus on a sequence of totally ordered requests through, for example, the Paxos protocol. Such a sequential execution model is becoming outdated on prevalent multi-core servers. Highly concurrent executions on multi-core architectures introduce non-determinism related to thread scheduling and lock contentions,(More)
Large-scale distributed storage systems have gained popularity for storing and processing ever increasing amount of data. Replication mechanisms are often key to achieving high availability and high throughput in such systems. Research on fundamental problems such as consensus has laid out a solid foundation for replication protocols. Yet, both the(More)
Activation of Ret, the receptor-tyrosine kinase for the glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs), results in the recruitment and assembly of adaptor protein complexes that function to transduce signals downstream of the receptor. Here we identify Dok-6, a novel member of the Dok-4/5 subclass of the p62 Dok family of(More)
Much work has been done to address the need for incentive models in real deployed peer-to-peer networks. In this paper, we discuss problems found with the incentive model in a large, deployed peer-to-peer network, Maze. We evaluate several alternatives, and propose an incentive system that generates preferences for wellbehaved nodes while correctly(More)
Maze is a P2P file-sharing system with an active and large user base. It is developed, deployed and operated by an academic research team. As such, it offers ample opportunities to conduct experiments to understand user behavior. Embedded in Maze is a set of incentive policies designed to encourage sharing and contribution. This paper presents an in-depth(More)