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— We study the impact of heterogeneity of nodes, in terms of their energy, in wireless sensor networks that are hierarchically clustered. In these networks some of the nodes become cluster heads, aggregate the data of their cluster members and transmit it to the sink. We assume that a percentage of the population of sensor nodes is equipped with additional(More)
—Recently, the notion of self-similarity has been shown to apply to wide-area and local-area network traffic. In this paper, we show evidence that the subset of network traffic that is due to World Wide Web (WWW) transfers can show characteristics that are consistent with self-similarity, and we present a hypothesized explanation for that self-similarity.(More)
We present what we believe to be the first thorough characterization of <i>live</i> streaming media content delivered over the Internet. Our characterization of over 3.5 million requests spanning a 28-day period is done at three increasingly granular levels, corresponding to clients, sessions, and transfers. Our findings support two important conclusions.(More)
Cloud computing's transition from a subject of research and innovation to a critical infrastructure is proceeding incredibly quickly. One potentially dangerous consequence of this speedy transition is the premature adoption and ossification of the models, technologies, and standards underlying this critical infrastructure. Further exacerbating this issue,(More)
Whether teaching in a classroom or a Massive Online Open Course it is crucial to present the material in a way that benefits the audience as a whole. We identify two important tasks to solve towards this objective; (1.) group students so that they can maximally benefit from peer interaction and (2.) find an optimal schedule of the educational material for(More)
Secure multi-party computation (MPC) allows multiple parties to perform a joint computation without disclosing their private inputs. Many real-world joint computation use cases, however, involve data analyses on very large data sets, and are implemented by software engineers who lack MPC knowledge. Moreover, the collaborating parties -- e.g., several(More)
Network scanners are a valuable tool for researchers and administrators, however they are also used by malicious actors to identify vulnerable hosts on a network. Upon the disclosure of a security vulnerability, scans are launched within hours. These opportunistic attackers enumerate blocks of IP addresses in hope of discovering an exploitable host.(More)
—We describe the definition, design, implementation , and deployment of a secure multi-party computation protocol and web application. The protocol and application allow groups of cooperating parties with minimal expertise and no specialized resources to compute basic statistical analytics on their collective data sets without revealing the contributions of(More)
We present a prototype of a distributed computational infrastructure, an associated high-level programming language, and an underlying formal framework that allow multiple parties to leverage their own cloud-based computational resources (capable of supporting MapReduce [27] operations) in concert with multi-party computation (MPC) to execute statistical(More)