Matthew Halpern

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Mobile Web applications have become an integral part of our society. They pose a high demand for application quality of service (QoS). However, the energy-constrained nature of mobile devices makes optimizing for QoS difficult. Prior art on energy efficiency optimizations has only focused on the trade-off between raw performance and energy consumption,(More)
In contrast to traditional computing systems, such as desktops and servers, that are programmed to perform “compute-bound” and “run-to-completion” tasks, mobile applications are designed for user interactivity. Factoring user interactivity into computer system design and evaluation is important, yet possesses many challenges. In(More)
In this paper, we assess the past, present, and future of mobile CPU design. We study how mobile CPU designs trends have impacted the end-user, hardware design, and the holistic mobile device. We analyze the evolution often cutting-edge mobile CPU designs released over the past seven years. Specifically, we report measured performance, power, energy and(More)
In this paper, we present findings and design decisions arisen while designing a review sheet within the confines of a pre-existing digital textbook, AdaptiveBook. Through user studies, we found that instructors and students cited a lack of both context and integration as the major problems in current high-tech teaching and studying tools. Because research(More)
Enterprise Web applications are moving towards server-side scripting using managed languages. Within this shifting context, <i>event-driven programming</i> is emerging as a crucial programming model to achieve scalability. In this paper, we study the microarchitectural implications of server-side scripting, JavaScript in particular, from a unique(More)
While many methods have been proposed to ensure data quality for objective tasks (in which a single correct response is presumed to exist for each item), estimating data quality with subjective tasks remains largely unexplored. Consider the popular task of collecting instance ratings from human judges: while agreement tends be high for instances having(More)
The traditional guardbanding approach to ensure processor reliability is becoming obsolete because it always over-provisions voltage and wastes a lot of energy. As a next-generation alternative, adaptive guardbanding dynamically adjusts chip clock frequency and voltage based on timing margin measured at runtime. With adaptive guardbanding, voltage guardband(More)