Optimal Elephant Flow Detection

Monitoring the traffic volumes of elephant flows, including the total byte count per flow, is a fundamental capability for online network measurements. We present an asymptotically optimal algorithm for solving this problem in terms of both space and time complexity. This improves on previous approaches, which can only count the number of packets in constant time. We evaluate our work on real packet traces, demonstrating an up to X2.5 speedup compared to the best alternative.Comment: Accepted to IEEE INFOCOM 201

I’m First: A Phenomenological Analysis of the University of North Carolina’s “Carolina Firsts” Interviews

This study analyzes interview videos and transcripts produced by the University of North Carolina at Chapel Hill. The first-generation interviews, known as “Carolina Firsts,” include current students, staff, and faculty. The phenomenological method was used to identify common themes in the videos and transcripts of six interviewees. Eight essential themes were revealed: the dream comes true, beating the odds, facing the unknown, a challenging first semester, reaching for the degree, it gets easier, the issue of pride, and Carolina keeps its promise. The eight themes identified provide new insights into similar communication experiences among Carolina Firsts interviewees. The study offers suggestions for future research in order to continue gaining new insights into first-generation undergraduate experiences

XRay: Enhancing the Web's Transparency with Differential Correlation

Today's Web services - such as Google, Amazon, and Facebook - leverage user data for varied purposes, including personalizing recommendations, targeting advertisements, and adjusting prices. At present, users have little insight into how their data is being used. Hence, they cannot make informed choices about the services they choose. To increase transparency, we developed XRay, the first fine-grained, robust, and scalable personal data tracking system for the Web. XRay predicts which data in an arbitrary Web account (such as emails, searches, or viewed products) is being used to target which outputs (such as ads, recommended products, or prices). XRay's core functions are service agnostic and easy to instantiate for new services, and they can track data within and across services. To make predictions independent of the audited service, XRay relies on the following insight: by comparing outputs from different accounts with similar, but not identical, subsets of data, one can pinpoint targeting through correlation. We show both theoretically, and through experiments on Gmail, Amazon, and YouTube, that XRay achieves high precision and recall by correlating data from a surprisingly small number of extra accounts.Comment: Extended version of a paper presented at the 23rd USENIX Security Symposium (USENIX Security 14

Extending Demand Response to Tenants in Cloud Data Centers via Non-intrusive Workload Flexibility Pricing

Participating in demand response programs is a promising tool for reducing energy costs in data centers by modulating energy consumption. Towards this end, data centers can employ a rich set of resource management knobs, such as workload shifting and dynamic server provisioning. Nonetheless, these knobs may not be readily available in a cloud data center (CDC) that serves cloud tenants/users, because workloads in CDCs are managed by tenants themselves who are typically charged based on a usage-based or flat-rate pricing and often have no incentive to cooperate with the CDC operator for demand response and cost saving. Towards breaking such "split incentive" hurdle, a few recent studies have tried market-based mechanisms, such as dynamic pricing, inside CDCs. However, such mechanisms often rely on complex designs that are hard to implement and difficult to cope with by tenants. To address this limitation, we propose a novel incentive mechanism that is not dynamic, i.e., it keeps pricing for cloud resources unchanged for a long period. While it charges tenants based on a Usage-based Pricing (UP) as used by today's major cloud operators, it rewards tenants proportionally based on the time length that tenants set as deadlines for completing their workloads. This new mechanism is called Usage-based Pricing with Monetary Reward (UPMR). We demonstrate the effectiveness of UPMR both analytically and empirically. We show that UPMR can reduce the CDC operator's energy cost by 12.9% while increasing its profit by 4.9%, compared to the state-of-the-art approaches used by today's CDC operators to charge their tenants

Incorporating Online Instruction in Academic Libraries: Getting Ahead of the Curve

A sea change in higher education is shaping the way many libraries deliver instruction to their students and faculty. Years of technological innovation and changes in the way that people discover and use information has made online instruction an essential part of a library\u27s teaching and learning program. In order to evaluate our library\u27s online instruction program and to determine its future goals, we analyzed the technology, pedagogical models, organizational structures, administrative supports, and partnerships we would need in order to succeed. Our findings may be useful for libraries reassessing their own online instruction programs

Telling timber tales in higher education: a reflection on my journey with digital storytelling

The challenges of the Higher Education landscape are the result of massification and globalisation. The general lack of preparedness in students and lack of academic literacy means that plagiarism is increasingly a challenge in written assignments. In the South African context, this is amplified, as students may be studying in their third or fourth language. Relying on students' affinity for visual learning, digital storytelling was first used as an alternative assessment method (to a written assignment) in 2011. This paper is a reflection on a lecturer's journey with digital storytelling, beginning with the first project in the Industrial Design programme at a University of Technology in South Africa. The short movie clips, known as digital stories, were created with off-the-shelf equipment and techniques, and any open source software available to the students. By evaluating the project using the lens of Authentic Learning, some of the benefits and challenges of using this alternative means of assessment could be identified. The authentic learning, the polished end products, the engagement of students with the material, the decidedly independent learning, and the collaborative practice were recognised as key benefits. The students also saw the visual orientation of the project, the digital literacy-building, and freedom of creative expression as benefits, and revealed their resourcefulness during the student-led project. This paper also acknowledges the two models of digital storytelling, the growth of communities of practice and the possibilities for further research into this growing area of learning in Higher Education