Umar Saif

FluBreaks: early epidemic detection from Google flu trends.

Background The Google Flu Trends service was launched in 2008 to track changes in the volume of online search queries related to flu-like symptoms. Over the last few years, the trend data produced by this service has shown a consistent relationship with the actual number of flu reports collected by the US Centers for Disease Control and Prevention (CDC), often identifying increases in flu cases weeks in advance of CDC records. However, contrary to popular belief, Google Flu Trends is not an early epidemic detection system. Instead, it is designed as a baseline indicator of the trend, or changes, in the number of disease cases. Objective To evaluate whether these trends can be used as a basis for an early warning system for epidemics. Methods We present the first detailed algorithmic analysis of how Google Flu Trends can be used as a basis for building a fully automated system for early warning of epidemics in advance of methods used by the CDC. Based on our work, we present a novel early epidemic detection system, called FluBreaks (dritte.org/flubreaks), based on Google Flu Trends data. We compared the accuracy and practicality of three types of algorithms: normal distribution algorithms, Poisson distribution algorithms, and negative binomial distribution algorithms. We explored the relative merits of these methods, and related our findings to changes in Internet penetration and population size for the regions in Google Flu Trends providing data. Results Across our performance metrics of percentage true-positives (RTP), percentage false-positives (RFP), percentage overlap (OT), and percentage early alarms (EA), Poisson- and negative binomial-based algorithms performed better in all except RFP. Poisson-based algorithms had average values of 99%, 28%, 71%, and 76% for RTP, RFP, OT, and EA, respectively, whereas negative binomial-based algorithms had average values of 97.8%, 17.8%, 60%, and 55% for RTP, RFP, OT, and EA, respectively. Moreover, the EA was also affected by the region’s population size. Regions with larger populations (regions 4 and 6) had higher values of EA than region 10 (which had the smallest population) for negative binomial- and Poisson-based algorithms. The difference was 12.5% and 13.5% on average in negative binomial- and Poisson-based algorithms, respectively. Conclusions We present the first detailed comparative analysis of popular early epidemic detection algorithms on Google Flu Trends data. We note that realizing this opportunity requires moving beyond the cumulative sum and historical limits method-based normal distribution approaches, traditionally employed by the CDC, to negative binomial- and Poisson-based algorithms to deal with potentially noisy search query data from regions with varying population and Internet penetrations. Based on our work, we have developed FluBreaks, an early warning system for flu epidemics using Google Flu Trends.

Structured Decomposition of Adaptive Applications

We describe an approach to automate certain high- level implementation decisions in a pervasive application, allowing them to be postponed until run time. Our system enables a model in which an application programmer can specify the behavior of an adaptive application as a set of open-ended decision points. We formalize decision points as goals, each of which may be satisfied by a set of scripts called Techniques. The set of Techniques vying to satisfy any goal is additive and may be extended at runtime without needing to modify or remove any existing techniques. Our system provides a framework in which Techniques may compete and interoperate at runtime in order to maintain an adaptive application. Technique development may be distributed and incremental, providing a path for the decentralized evolution of applications. Benchmarks show that our system imposes reasonable overhead during application startup and adaptation.

Communication primitives for ubiquitous systems or RPC considered harmful

RPC is widely used to access and modify remote state. Its procedural call semantics are argued as an efficient unifying paradigm for both local and remote access. Our experience with ubiquitous device control systems has shown otherwise. RPC semantics of a synchronous, blocking invocation on a statically typed interface are overly restrictive, inflexible, and fail to provide an efficient unifying abstraction for accessing and modifying state in ubiquitous systems. This paper considers other alternatives and proposes the use of comvets (conditional, mobility aware events) as the unifying generic communication paradigm for such systems.

Internet access to a home area network

The AutoHan project implements a self-configuring software architecture for home area networks that offers an XML-based registry and HTTP-based service. The article begins by introducing the low-level architectures of the AutoHan project that enable different networking technologies to interoperate and define one logical IP network. It then describes the two core services that enable resources to export, discover and interoperate with AutoHan by using these low-level architectures. Finally, the article discusses naming and addressing issues for Internet access and shows how XML and HTTP allowed extension of the system to support Internet access through IHan (Internet home area network).

Service-Oriented Network Sockets

This paper presents the design and implementation of service-oriented network sockets (SoNS) for accessing services in a dynamically changing networked environment. A service-oriented network socket takes a high-level description of a service and opportunistically connects to the best provider of that service in the changing characteristics of a mobile system. An application states its high-level service requirements as a set of constraints on the properties required in a suitable resource and SoNS continuously monitors, evaluates and compares the available resources and (re-)connects to the resource that best satisfies the specified constraints. Unlike content-based routing systems, SoNS is an end-host system, interposed at the session-binding layer, and offers connection-oriented semantics. SoNS’ interface allows an application to tailor the planning policy used to establish and rebind a network session. SoNS is based on an extensible architecture to leverage the wide-range of emerging technologies for discovering and locating resources in a mobile system. SoNS integrates a service-oriented abstraction with the traditional operating system interface for accessing network services, making it simpler to develop pervasive, mobile applications. We present an implementation for a mobile handheld device, analyze the performance of our system and describe an application to demonstrate the utility of our system.

Viral entertainment as a vehicle for disseminating speech-based services to low-literate users

Entertainment has recently been shown to be a powerful motivator for mastering new technologies. We therefore set out to use viral entertainment to introduce telephone-based, speech-based services to low-literate people in developing countries. We describe Polly, a simple voice manipulation and forwarding system that went viral in Pakistan last year. Seeded once by 32 low-skilled office workers in a Pakistani university, in 3 weeks Polly amassed 2,032 users and 10,629 interactions. From analyzing the traffic and its content, it is evident that Polly has been used extensively for entertainment and social contact, but it has also been put to an unintended use as a voicemail and group messaging facility. This demonstrated the potential for speech based services, and the pent-up demand for entertainment, among our target population. Also of note, Pollys viral spread crossed gender and age boundaries and even established itself in a female population. However, it appears to have not crossed socioeconomic boundaries.

A dynamic platform for runtime adaptation

We present a middleware platform for assembling pervasive applications that demand fault-tolerance and adaptivity in distributed, dynamic environments. Unlike typical adaptive middleware approaches, in which sophisticated component model semantics are embedded into an existing, underlying platform (e.g., CORBA, COM, EJB), we propose a platform that imposes minimal constraints for greater flexibility. Such a tradeoff is advantageous when the platform is targeted by automatic code generators that inherently enforce correctness by construction. Applications are written as simple, single-threaded programs that assemble and monitor a set of distributed components. The approach decomposes applications into two distinct layers: (1) a distributed network of interconnected modules performing computations, and (2) constructor logic that assembles that network via a simple block-diagram construction API. The constructor logic subsequently monitors the configured system via a stream of high-level events, such as notifications of resource availability or failures, and consequently provides a convenient, centralized location for reconfiguration and debugging. The component network is optimized for performance, while the construction API is optimized for ease of assembly.

Internet for the developing world: Offline internet access at modem-speed dialup connections

Users in the developing-world are typically forced to access the Internet at a fraction of the speed achievable by a standard v.90 modem. In this paper we present an architecture to enable offline access to the Internet at the maximum possible speed achievable by a standard modem. Our proposed architecture provides a mechanism for multiplexing the scarce and expensive international Internet bandwidth over higher bandwidth p2p dialup connections within a developing country. Our system combines a number of architectural components, such as incentive-driven p2p data transfer, intelligent connection interleaving and content-prefetching. This paper presents a detailed design, implementation and evaluation of our dialup p2p data transfer architecture inspired by Bittorrent.

BitTorrent for the less privileged

BitTorrent is a hugely popular peer-to-peer file sharing system. In countries where broadband Internet is widespread, BitTorrent accounts for as much as 70% of the overall Internet traffic. In contrast, in developing countries, BitTorrent is almost unusable on the typically low bandwidth dialup connections. In this paper, we present a BitTorrent client called BitMate that is designed to enhance the performance of hosts with low-bandwidth connections. Importantly, BitMate enhances the performance of low-bandwidth nodes without cheating, circumventing the fairness policy of BitTorrent or adversely affecting the performance of other peers. In fact, BitMate drives its performance by scrupulously implementing the fairness philosophy of BitTorrent. BitMate outperforms vanilla BitTorrent by as much as 70% in download performance, while at the same time improving upload contribution by as much as 1000%! BitMate also outperforms strategic clients like BitTyrant in low-bandwidth conditions by as much as 60% in download performance.

Reducing configuration overhead with goal-oriented programming

The rapid increase in the number and variety of consumer-level electronic devices without the corresponding development of device management technology has lead to a configuration nightmare. We propose to use goal-oriented programming over a substrate of network-portable objects to help reduce the amount of configuration users must do in order to have their applications use their devices efficiently. We detail an architecture and describe a prototype system using existing pervasive computing technology that plays music on the most appropriate devices without requiring user interaction and configuration