ZapDroid: Managing Infrequently Used Applications on Smartphones

ABSTRACT User surveys have shown that a typical user has over a hundred apps on her smartphone [1], but stops using many of them. We conduct a user study to identify such unused apps, which we call zombies, and show via experiments that zombie apps consume significant resources on a user's smartphone and access her private information. We then design and build ZapDroid, which enables users to detect and silo zombie apps in an e↵ective way to prevent their undesired activities. If and when the user wishes to resume using such an app, ZapDroid restores the app quickly and e↵ectively. Our evaluations show that: (i) ZapDroid saves twice the energy from unwanted zombie app behaviors as compared to apps from the Play Store that kill background unwanted processes, and (ii) it e↵ectively prevents zombie apps from using undesired permissions. In addition, ZapDroid is energye cient, consuming < 4% of the battery per day

TIDE: A User-Centric Tool for Identifying Energy Hungry Applications on Smartphones

Abstract-Today, many smartphone users are unaware of what applications (apps) they should stop using to prevent their battery from running out quickly. The problem is identifying such apps is hard due to the fact that there exist hundreds of thousands of apps and their impact on the battery is not well understood. We show via extensive measurement studies that the impact of an app on battery consumption depends on both environmental (wireless) factors and usage patterns. Based on this, we argue that there exists a critical need for a tool that allows a user to (a) identify apps that are energy hungry, and (b) understand why an app is consuming energy, on her phone. Towards addressing this need, we present TIDE, a tool to detect high energy apps on any particular smartphone. TIDE's key characteristic is that it accounts for usage-centric information while identifying energy hungry apps from among a multitude of apps that run simultaneously on a user's phone. Our evaluation of TIDE on a testbed of Android-based smartphones, using weeklong smartphone usage traces from 17 real users, shows that TIDE correctly identifies over 94% of energy-hungry apps and has a false positive rate of < 6%

Sibyl:A Practical Internet Route Oracle

Network operators measure Internet routes to troubleshoot problems, and researchers measure routes to characterize the Internet. However, they still rely on decades-old tools like traceroute, BGP route collectors, and Looking Glasses, all of which permit only a single query about Internet routes—what is the path from here to there? This limited interface complicates answering queries about routes such as "find routes traversing the Level3/AT&T peering in Atlanta," to understand the scope of a reported problem there. This paper presents Sibyl, a system that takes rich queries that researchers and operators express as regular expressions, then issues and returns traceroutes that match even if it has never measured a matching path in the past. Sibyl achieves this goal in three steps. First, to maximize its coverage of Internet routing, Sibyl integrates together diverse sets of traceroute vantage points that provide complementary views, measuring from thousands of networks in total. Second, because users may not know which measurements will traverse paths of interest, and because vantage point resource constraints keep Sibyl from tracing to all destinations from all sources, Sibyl uses historical measurements to predict which new ones are likely to match a query. Finally, based on these predictions, Sibyl optimizes across concurrent queries to decide which measurements to issue given resource constraints. We show that Sibyl provides researchers and operators with the routing information they need—in fact, it matches 76% of the queries that it could match if an oracle told it which measurements to issue

Oasis: An OverlayAware

Overlays have enabled several new and popular distributed applications such as Akamai, Kazaa, and Bittorrent. However, the lack of an overlay-aware network stack has hindered the widespread use of general purpose overlay packet delivery services [16, 29, 26]. In this paper, we describe the design and implementation of Oasis, a system and toolkit that enables legacy operating systems to access overlay-based packet delivery services. Oasis combines a set of ideas – network address translation, name resolution, packet capture, dynamic code execution – to provide greater user choice. We are in the process of making the Oasis toolkit available for public use, specifically, to ease the development of PlanetLab-based packet delivery services

A Generic Language for Application-Specific Flow Sampling

Flow records gathered by routers provide valuable coarse-granularity traffic information for several measurement-related network applications. However, due to high volumes of traffic, flow records need to be sampled before they are gathered. Current techniques for producing sampled flow records are either focused on selecting flows from which statistical estimates of traffic volume can be inferred, or have simplistic models for applications. Such sampled flow records are not suitable for many applications with more specific needs, such as ones that make decisions across flows. As a first step towards tailoring the sampling algorithm to an application’s needs, we design a generic language in which any particular application can express the classes of traffic of its interest. Our evaluation investigates the expressive power of our language, and whether flow records have sufficient information to enable sampling of records of relevance to applications. We use templates written in our custom language to instrument sampling tailored to three different applications—BLINC, Snort, and Bro. Our study, based on month-long datasets gathered at two different network locations, shows that by learning local traffic characteristics we can sample relevant flow records near-optimally with low false negatives in diverse applications

An efficient algorithm for virtual-wavelength-path routing minimizing average number of hops

Abstract—In this paper, we present a novel heuristic for routing and wavelength assignment in Virtual-Wavelength-Path (VWP) routed WDM optical networks. We are the first to take up the approach of both minimizing the network cost as well as maximizing the resource utilization. Our algorithm not only minimizes the number of wavelengths required for supporting the given traffic demand on any given topology, but also aims to minimize the mean hop length of all the lightpaths which in turn maximizes the resource utilization. The algorithm initially assigns the minimum hop path to each route and then performs efficient rerouting to reduce the number of wavelengths required while also trying to minimize the average hop length. To further reduce the network cost, we also propose a wavelength assignment procedure for VWP routed networks which minimizes the number of wavelength converters required. Our algorithm has been tested on various topologies for different types of traffic demands and has been found to give solutions much better than previous standards for this problem. Index Terms—WDM optical network, Virtual-Wavelength-Path routed network, Routing and wavelength assignment, Wavelength conversion, Network cost, Resource utilizatio