A Study Of Induced Grid Noise.

PhDElectromagnetismUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/181266/2/0007745.pd

Report on induced grid noise measurements

http://deepblue.lib.umich.edu/bitstream/2027.42/7876/5/bad3910.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/7876/4/bad3910.0001.001.tx

A Conversation with Thomas and Elizabeth Talpey

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Designing NFS with RDMA for Security, Performance and Scalability

NFS has traditionally used TCP or UDP as the underlying transport. However, the overhead of these stacks has limited both the performance and scalability of NFS. Recently, high-performance network such as InfiniBand have been deployed. These networks provide low latency of a few microseconds and high bandwidth for large messages up to 20 Gbps. Because of the unique characteristics of NFS protocols, previous designs of NFS with RDMA were unable to exploit the improved bandwidth of networks such as InfiniBand. Also, they leave the server open to attacks from malicious clients. In this paper, we discuss the design principles for implementing NFS/RDMA protocols. We propose, implement and evaluate an alternate design for NFS/RDMA on InfiniBand, which can significantly improve the security of the server, compared to the previous design. In addition, we evaluate the performance bottlenecks of using RDMA operations in NFS protocols and propose strategies and designs that tackle these overheads. With the best of these strategies and designs, we demonstrate throughput of 700 MB/s on the OpenSolaris NFS/RDMA design and 900 MB/s on the Linux design and an application level improvement in performance of up to 50%. We also evaluate the scalability of the RDMA transport in a multi-client setting, with a RAID array of disks. Our design has been integrated into the OpenSolaris kernel. 1

Discriminative ability of lower limb strength and power measures in lacrosse athletes

The objective of this investigation was to compare isokinetic strength, countermovement jump and drop jump variables between high-contributors and low-contributors within NCAA Division I Men's and Women's lacrosse athletes. Men's (N=36) and Women's (N=30) NCAA Division I lacrosse athletes completed strength testing of the quadriceps and hamstring across three speeds (60°·s -1, 180°·s -1, 300°·s -1), countermovement and drop jumps. To determine the discriminative ability of select lower-limb strength and power characteristics participants were categorized as high-contributors (Males N=18, age=20.3±0.4 yrs, height=183.9±5.5 cm, mass=90.8±5.8 kg; Females N=15, age=20.8±0.8 yrs, height=169.3±6.7 cm, mass=64.1±7.2 kg) or low-contributors (Males N=18, age=19.5±0.2 yrs, height=184.1±5.6 cm; mass=87.9±8.1 kg; Females N=15, age=19.7±0.2 yrs, height=169.8±7.0 cm, mass=62.9±7.7 kg) based upon the number of games the participants competed in during the regular season. Within the male cohort, moderate significant (p<0.05) differences were observed between high-contributors and low-contributors in isokinetic hamstring strength of the left leg at 300°·s -1(d=0.69) and peak power in countermovement jump (d= 0.68). Within the women's cohort a large (d= 0.87) significant difference (p<0.05) in isokinetic strength of the left hamstring was observed between high-contributors and low-contributors at 60°·s -1. Hamstring strength and lower-limb power are important strength measures for lacrosse performance and should be prioritized in training prescription for lacrosse athletes. © 2023 Georg Thieme Verlag. All rights reserved

IOFlow: A Software-Defined Storage Architecture

In data centers, the IO path to storage is long and complex. It comprises many layers or “stages ” with opaque interfaces between them. This makes it hard to enforce end-to-end policies that dictate a storage IO flow’s performance (e.g., guarantee a tenant’s IO bandwidth) and routing (e.g., route an untrusted VM’s traffic through a sanitization middlebox). These policies require IO differentiation along the flow path and global visibility at the control plane. We design IOFlow, an architecture that uses a logically centralized control plane to enable high-level flow policies. IOFlow adds a queuing abstraction at data-plane stages and exposes this to the controller. The controller can then translate policies into queuing rules at individual stages. It can also choose among multiple stages for policy enforcement. We have built the queue and control functionality at two key OS stages – the storage drivers in the hypervisor and the storage server. IOFlow does not require application or VM changes, a key strength for deployability. We have deployed a prototype across a small testbed with a 40 Gbps network and storage devices. We have built control applications that enable a broad class of multipoint flow policies that are hard to achieve today.