Online Scheduling on Identical Machines using SRPT

Due to its optimality on a single machine for the problem of minimizing average flow time, Shortest-Remaining-Processing-Time (\srpt) appears to be the most natural algorithm to consider for the problem of minimizing average flow time on multiple identical machines. It is known that \srpt achieves the best possible competitive ratio on multiple machines up to a constant factor. Using resource augmentation, \srpt is known to achieve total flow time at most that of the optimal solution when given machines of speed $2- \frac{1}{m}$. Further, it is known that \srpt's competitive ratio improves as the speed increases; \srpt is $s$-speed $\frac{1}{s}$-competitive when $s \geq 2- \frac{1}{m}$. However, a gap has persisted in our understanding of \srpt. Before this work, the performance of \srpt was not known when \srpt is given (1+\eps)-speed when 0 < \eps < 1-\frac{1}{m}, even though it has been thought that \srpt is (1+\eps)-speed $O(1)$-competitive for over a decade. Resolving this question was suggested in Open Problem 2.9 from the survey "Online Scheduling" by Pruhs, Sgall, and Torng \cite{PruhsST}, and we answer the question in this paper. We show that \srpt is \emph{scalable} on $m$ identical machines. That is, we show \srpt is (1+\eps)-speed O(\frac{1}{\eps})-competitive for \eps >0. We complement this by showing that \srpt is (1+\eps)-speed O(\frac{1}{\eps^2})-competitive for the objective of minimizing the $\ell_k$-norms of flow time on $m$ identical machines. Both of our results rely on new potential functions that capture the structure of \srpt. Our results, combined with previous work, show that \srpt is the best possible online algorithm in essentially every aspect when migration is permissible.Comment: Accepted for publication at SODA. This version fixes an error in a preliminary versio

Meridian

For this year-long project, I set out to produce a film that would capture the energy and community of the Meridian Coffeehouse on the campus of the College of William & Mary. For three years, I have played an active role in the management of the space, from booking, managing, and recording live music events to hosting various shifts to watch films and create music. Being a double major in Anthropology and Film & Media Studies, and having been further inspired by a Visual Anthropology course that I took at the University of St Andrews in Spring 2018, I decided to attempt a visual ethnographic approach to document the Meridian. I focused on my own relationship to the space and the people within it as a participant observer, pondering the ethics of the camera as a documentary tool and considering various stylistic and ideological approaches to representing a space and the people in it through a visual medium. The primary product of this Honors Thesis is the film, which is available on YouTube under the title Meridian - A Film by Ben Fox. This paper serves as a reflection on the process of filming and editing the documentary, and includes some context about the space and my own experiences to aid in the viewing of the film. The link to the film is here: https://youtu.be/ibKYapZr1D

Why Taiwan‘s Sustainable Energy Policy Matters

By establishing a series of similarities to the U.S., this study demonstrates the potential for Taiwan‘s recent progress on sustainable energy policy to influence American policymakers. An assessment of Taiwan‘s current energy situation is contextualized within its economic development and political institutions. Taiwan‘s energy legislation has already leveraged significant financial investment to reshape an economy increasingly focused on clean energy technology. In the future, Taiwan will continue to pursue aggressive energy legislation and the U.S. may draw inspiration from Taiwan‘s sustainable energy reforms

Cover Letter

The Richmond Journal of Law and Technology is proud to present its first issue of the 2013-2014 academic year. First published in 1995, JOLT is the world’s first exclusively online law review. JOLT strives to discuss new and emerging issues that fall squarely at the intersection of technology and the law. Today, with the publication of Issue One of its Twentieth Volume, JOLT aims to continue this tradition by providing relevant, insightful, and well-written articles that will drive discussion on these topics

Cover Letter

The Richmond Journal of Law and Technology is proud to present its third issue of the 2013-2014 academic year. First published in 1995, JOLT is the world’s first exclusively online law review. JOLT strives to discuss new and emerging issues that fall squarely at the intersection of technology and the law. With this goal in mind, we are proud to announce the publication of the following articles

Cover Letter

The Richmond Journal of Law and Technology is proud to present the final issue of the Twentieth Volume. First published in 1995, JOLT isthe world’s first exclusively online law review. JOLT strives to discuss new and emerging issues that fall squarely at the intersection oftechnology and the law. With this goal in mind, we are proud to announce the publication of the following articles

Characterizing Transition Temperature Gas in the Galactic Corona

We present a study of the properties of the transition temperature (T~10^5 K) gas in the Milky Way corona, based on measurements of OVI, NV, CIV, SiIV and FeIII absorption lines seen in the far ultraviolet spectra of 58 sightlines to extragalactic targets, obtained with Far-Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph. In many sightlines the Galactic absorption profiles show multiple components, which are analyzed separately. We find that the highly-ionized atoms are distributed irregularly in a layer with a scaleheight of about 3 kpc, which rotates along with the gas in the disk, without an obvious gradient in the rotation velocity away from the Galactic plane. Within this layer the gas has randomly oriented velocities with a dispersion of 40-60 km/s. On average the integrated column densities are log N(OVI)=14.3, log N(NV)=13.5, log N(CIV)=14.2, log N(SiIV)=13.6 and log N(FeIII)=14.2, with a dispersion of just 0.2 dex in each case. In sightlines around the Galactic Center and Galactic North Pole all column densities are enhanced by a factor ~2, while at intermediate latitudes in the southern sky there is a deficit in N(OVI) of about a factor 2, but no deficit for the other ions. We compare the column densities and ionic ratios to a series of theoretical predictions: collisional ionization equilibrium, shock ionization, conductive interfaces, turbulent mixing, thick disk supernovae, static non-equilibrium ionization (NIE) radiative cooling and an NIE radiative cooling model in which the gas flows through the cooling zone. None of these models can fully reproduce the data, but it is clear that non-equilibrium ionization radiative cooling is important in generating the transition temperature gas.Comment: 99 pages, 11 figures, with appendix on Cooling Flow model; only a sample of 5 subfigures of figure 2 included - full set of 69 available through Ap

Clustering with Faulty Centers

In this paper we introduce and formally study the problem of k-clustering with faulty centers. Specifically, we study the faulty versions of k-center, k-median, and k-means clustering, where centers have some probability of not existing, as opposed to prior work where clients had some probability of not existing. For all three problems we provide fixed parameter tractable algorithms, in the parameters k, d, and ?, that (1+?)-approximate the minimum expected cost solutions for points in d dimensional Euclidean space. For Faulty k-center we additionally provide a 5-approximation for general metrics. Significantly, all of our algorithms have a small dependence on n. Specifically, our Faulty k-center algorithms have only linear dependence on n, while for our algorithms for Faulty k-median and Faulty k-means the dependence is still only n^(1 + o(1))