Venugopal Vasudevan

A framework for network aware caching for video on demand systems

Video on Demand (VoD) services allow users to select and locally consume remotely stored content. We investigate the use of caching to solve the scalability issues of several existing VoD providers. We propose metrics and goals that define the requirements of a caching framework for CDNs of VoD systems. Using data logs collected from Motorola equipment from Comcast VoD deployments we show that several classic caching solutions do not satisfy the proposed goals. We address this issue by developing novel techniques for predicting future values of several metrics of interest. We rely on computed predictions to define the penalty imposed on the system, both network and caching sites, when not storing individual items. We use item penalties to devise novel caching and static content placement strategies. We use the previously mentioned data logs to validate our solutions and show that they satisfy all the defined goals.

Infiltrating Social Network Accounts: Attacks and Defenses

Social networks collect and make public an unprecedented amount of user location information. This raises significant user privacy concerns. In this chapter, we describe social networking infiltration attacks, where adversaries befriend random victims of their choice and acquire access to their private information. To address this problem, we propose verification mechanisms that use location information certified by geosocial networks to quantify the context shared by a user and an inviter. We develop novel visual notifications that leverage the outcome of the proposed verifications to inform users about the context they share with inviters. The impact of location information makes it however vulnerable to attacks: users can rely on existing tools to report fraudulent locations. We describe venue centric location verification solutions that are resilient to powerful adversaries.

Cache & Carry: Seamless Content Consumption in an Intermittently Connected World

Even as mobile devices as well as wireless networks become increasingly capable, newer content-intensive application place increasing demands on the resources of these devices. Some of these applications make conflicting resource demands making it difficult for device platforms to guarantee acceptable user experience. Thus, a resource aware middleware is needed that mobile applications can leverage to manage their content. In this paper we discuss Cache & Carry, a framework for mobile devices that intelligently manages scarce resources on the mobile device across multiple applications. The framework takes into consideration changing mobile device characteristics such as available battery and storage as well as changing network characteristics such as availability of multiple networks, their perceived cost, their available bandwidths etc., to provide an optimal end user experience.