Using Channel Output Feedback to Increase Throughput in Hybrid-ARQ

Hybrid-ARQ protocols have become common in many packet transmission systems due to their incorporation in various standards. Hybrid-ARQ combines the normal automatic repeat request (ARQ) method with error correction codes to increase reliability and throughput. In this paper, we look at improving upon this performance using feedback information from the receiver, in particular, using a powerful forward error correction (FEC) code in conjunction with a proposed linear feedback code for the Rayleigh block fading channels. The new hybrid-ARQ scheme is initially developed for full received packet feedback in a point-to-point link. It is then extended to various different multiple-antenna scenarios (MISO/MIMO) with varying amounts of packet feedback information. Simulations illustrate gains in throughput.Comment: 30 page

Library Marketing on a Small Liberal Arts Campus: Assessing Communication Preferences

As part of a newly created library marketing plan, librarians at the College of Wooster undertook a study of the communication preferences of students, faculty, and staff in early 2015. The results of the survey helped to develop a comprehensive picture of what library resources and services these constituencies are interested in learning about, as well as when, where, and how they prefer to learn about them. This article describes the development, distribution, results, and analysis of the survey, and highlights the importance of campus-specific library marketing practices

Myometrial transcriptional signatures of human parturition

The process of parturition involves the transformation of the quiescent myometrium (uterine smooth muscle) to the highly contractile laboring state. This is thought to be driven by changes in gene expression in myometrial cells. Despite the existence of multiple myometrial gene expression studies, the transcriptional programs that initiate labor are not known. Here, we integrated three transcriptome datasets, one novel (NCBI Gene Expression Ominibus: GSE80172) and two existing, to characterize the gene expression changes in myometrium associated with the onset of labor at term. Computational analyses including classification, singular value decomposition, pathway enrichment, and network inference were applied to individual and combined datasets. Outcomes across studies were integrated with multiple protein and pathway databases to build a myometrial parturition signaling network. A high-confidence (significant across all studies) set of 126 labor genes were identified and machine learning models exhibited high reproducibility between studies. Labor signatures included both known (interleukins, cytokines) and unknown (apoptosis, , cell proliferation/differentiation) pathways while cyclic AMP signaling and muscle relaxation were associated with non-labor. These signatures accurately classified and characterized the stages of labor. The data-derived parturition signaling networks provide new genes/signaling interactions to understand phenotype-specific processes and aid in future studies of parturition

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Harnessing the benefits of noisy feedback

The availability of feedback in a communications system opens the door to many new transmission techniques. In this work, the area of linear feedback coding is investigated for its utility in different communications scenarios. Linear feedback codes are communications schemes in which the transmissions are a strictly linear function of the message to be sent and side-information supplied by feedback from the receiver. This particular class of transmission strategies is alluring not only because of its inherent low complexity but also its proven benefits for reliability. However, the previous demonstrated advantages of these techniques were hinged upon a very impractical assumption: the feedback information sent back by the receiver is received perfectly at the transmitter. This assumption, which has allowed for valuable theoretical work in feedback communications, also greatly inhibits the work that invokes it. Thus, in this work, we investigate the utility of the class of linear feedback codes when this assumption is not made or, explicitly, when the side-information present at the receiver is assumed to be noisy. Specifically, three communication systems are considered: point-to-point systems, multiple-antenna packet-based systems, and multiuser systems. It is shown in all three settings that through the introduction of simple, linear transmission strategies one can greatly increase the reliability and/or throughput of communication systems

Precursor to crime : an instrumental variable analysis of the effects of meth supply interdictions on crime.

In the late 1990s, the use of methamphetamines (meth) grew substantially. At the same time, crime fell prodigiously, seemingly at the same time as two governmental supply interdictions on two key chemical precursors of meth. The “War on Drugs” has been the subject of continuous and contentious discussion for many years, but very little in the way of causal evidence has been produced, except for one paper by Dobkin and Nicosia from 2009 that finds no effect from these interdictions on property or violent crime. Notably, Dobkin and Nicosia use data from California alone. This paper expands upon their work by utilizing a procedure similar to that used by Cunningham and Finlay in their 2012 examination of the effect of these same interdictions on the foster care system. This paper finds that these interdictions had no effect nationwide on the levels of either property or violent crime

Biologically Inspired Multi-Robot System based on Wolf Hunting Behavior

Studies involving the group predator behavior of wolves have inspired multiple robotic architectures to mimic these biological behaviors in their designs and research. In this work, we aim to use robotic systems to mimic wolf packs\u27 single and group behavior. This work aims to extend the original research by Weitzenfeld et al [7] and evaluate under a new multi-robot robot system architecture. The multiple robot architecture includes a \u27Prey\u27 pursued by a wolf pack consisting of an \u27Alpha\u27 and \u27Beta\u27 robotic group. The Alpha Wolf\u27 will be the group leader, searching and tracking the \u27Prey.\u27 At the same time, the multiple Beta \u27Wolves\u27 will follow behind the Alpha, tracking and maintaining a set distance in the formation. The robotic systems used are multiple raspberry pi-robots designed in the USF bio-robotics lab that use a combination of color cameras and distance sensors to assist the Beta \u27Wolves\u27 in keeping a set distance between the Alpha Wolf and themselves. Several experiments were performed in simulation, using Webots, and with physical robots. An analysis was done comparing the performance of the physical robot in the real world to the virtual robot in the simulated environment