Towards Practical Oblivious RAM

We take an important step forward in making Oblivious RAM (O-RAM) practical. We propose an O-RAM construction achieving an amortized overhead of 20X-35X (for an O-RAM roughly 1 terabyte in size), about 63 times faster than the best existing scheme. On the theoretic front, we propose a fundamentally novel technique for constructing Oblivious RAMs: specifically, we partition a bigger O-RAM into smaller O-RAMs, and employ a background eviction technique to obliviously evict blocks from the client-side cache into a randomly assigned server-side partition. This novel technique is the key to achieving the gains in practical performance

String Cosmology: An Update

A string cosmology scenario ("pre-big-bang") postulates that the evolution of the Universe starts from a state of very small curvature and coupling, undergoes a long phase of dilaton-driven kinetic inflation and at some later time joins smoothly standard radiation dominated cosmological evolution, thus giving rise to a singularity free inflationary cosmology. I report on recent progress in understanding some outstanding issues such as initial conditions, graceful exit transition and generation of inhomogeneity perturbations.Comment: 11 pages, 1 eps figure, Latex, based on talk at COSMO9

Ram Essential

The underlying causes of food insecurity are complex and often intertwined with related issues that affect a student’s ability to meet even basic needs, such as housing, employment and health care, forcing them to choose between their well-being and their education. The latest Hunger in America report finds that about 10 percent of Feed America’s 46.5 million adult clients are college students. That equates to 2 million full-time college students. “Of those surveyed by the emergency food services network, roughly 30.5 percent of students reported that they were forced to choose between food and educational expenses at some point over the last year.”1 In response, colleges and universities, including VCU, have sprung into action, and the number of campus food pantries at higher educational institutions has risen from a handful in 2009 to more than 500 in 2017.2 But changing food insecurity to food security goes beyond providing just food. It involves a comprehensive approach to providing resources that address the causes and results of being food insecure. Ram Essentials is a holistic approach to addressing basic needs insecurity among VCU students by asking the question, What is essential for our students to be successful? The project focuses on raising the awareness of all existing VCU resources and disseminating them widely through a single user-friendly portal to enhance students’ experience, academic achievement and physical and mental well-being

A Kinematic Measurement of Ram Pressure in the Outer Disk of Regular Galaxies

While most ram pressure studies have focused on ram pressure stripping in galaxy clusters, we devise a novel approach based on a kinematic measurement of ram pressure perturbations in HI velocity fields for intergalactic material (IGM) densities and relative velocities that are one to two orders of magnitude lower than in galaxies showing ram pressure stripping. Our model evaluates ram pressure induced kinematic terms in gas disks with constant inclination as well as those with a warped geometry. Ram pressure perturbations are characterized by kinematic modes of even order, m=0 and m=2, corresponding to a ram wind perpendicular and parallel to the gas disk, respectively. Long-term consequences of ram pressure, such as warped disks as well as uncertainties in the disk geometry typically generate uneven modes (m=1 and m=3), that are clearly distinguishable from the kinematic ram pressure terms. We have applied our models to three nearby isolated galaxies, utilizing Markov Chain Monte Carlo fitting routines to determine ram pressure perturbations in the velocity fields of NGC 6946 and NGC 3621 of ~30km s$^{-1}$ (effective line-of-sight velocity change) at HI column densities below (4-10)$\times$10$^{20}$cm$^{-2}$ (at radial scales greater than ~15kpc). In contrast, NGC 628 is dominated by a strongly warped disk. Our model fits reveal the three-dimensional vector of the galaxies' movement with respect to the IGM rest-frame and provide constraints on the product of speed with IGM density, opening a new window for extragalactic velocity measurements and studies of the intergalactic medium.Comment: 34 pages, 28 figures, accepted for publication in MNRA

Ram Opportunity

RAM Opportunity is a self-sustaining mentoring and experiential learning program designed to serve high school students in the local community through programs led by graduate student mentors. RAM Opportunity operates using a plug-and-play structure that can be implemented in the arts, business, education, humanities, sciences, or any other discipline. Partnerships will be formed with local high schools and their guidance counseling services to develop a pipeline for potential students to participate in the program. The program benefits VCU by enhancing engagement with the local community, generating interest in high school students pursuing post-secondary education at VCU, and developing graduate students by providing professional development funding and real-world teaching and mentoring experience

The "Ram Effect": A "Non-Classical" Mechanism for Inducing LH Surges in Sheep

During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the "ram effect" in ewes that had a "precocious" LH surge (starting within 6 hours), a "normal" surge (between 6 and 28h) and "late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. "Precocious" LH surges were not preceded by a large increase in E2 unlike "normal" surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the "precocious" LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the "ram effect". Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators

FPGA-Based Implementation of RAM with Asymmetric Port Widths for Run-Time Reconfiguration

In this paper, we present a HDL description of a RAM with asymmetric port widths which allows read and write operations with different data size. This RAM is suitable for implementing run-time reconfigurable systems in FPGA. The proposed RAM specification has been tested with different target devices.Ministerio de Educación y Ciencia TEC2006-11730-C03-0