Shuffling with a Croupier: Nat-Aware Peer-Sampling

Despite much recent research on peer-to-peer (P2P) protocols for the Internet, there have been relatively few practical protocols designed to explicitly account for Network Address Translation gateways (NATs). Those P2P protocols that do handle NATs circumvent them using relaying and hole-punching techniques to route packets to nodes residing behind NATs. In this paper, we present Croupier, a peer sampling service (PSS) that provides uniform random samples of nodes in the presence of NATs in the network. It is the first NAT-aware PSS that works without the use of relaying or hole-punching. By removing the need for relaying and hole-punching, we decrease the complexity and overhead of our protocol as well as increase its robustness to churn and failure. We evaluated Croupier in simulation, and, in comparison with existing NAT-aware PSS’, our results show similar randomness properties, but improved robustness in the presence of both high percentages of nodes behind NATs and massive node failures. Croupier also has substantially lower protocol overhead

Evaluation of the Effectiveness of ACK Filtering and ACK Congestion Control in Mitigating the Effects of Bandwidth Asymmetry

The user demand for high speed and ubiquitous connectivity has led to the development and deployment of many new technologies, such as DSL and satellite-based networks, for accessing the Internet network. The goal of these technologies is to mitigate the bottleneck. Other technologies, such as wireless and packet radio networks aimed at providing the user with unrestricted access to their mobile devices and the Internet. Given that these networks are increasingly being deployed as high-speed access networks, it is highly desirable to achieve good network performance over such networks. These technologies show different characteristics (asymmetry) in uplink and downlink directions. Network asymmetry (uneven bandwidth) can negatively affect the performance of feedback-based transport protocol such as Transmission Control Protocol (TCP). This is because that congestion in any direction can affect the flow of feedback in the other direction. ACK Filtering and ACK Congestion Control techniques are used to diminish the congestion on the upstream link. These techniques suffer from sender burstiness and a slowdown in congestion window growth problems. This project addresses the TCP performance problems caused by network asymmetry and discuss the reasons for the inapplicability between TCP and asymmetric networks. It studies the effectiveness of these techniques in mitigating the effects of bandwidth asymmetry in TCP/IP networks and provides suggestions to overcome the problems associated with these techniques. Based on the performance model presented in this project, achieving optimum TCP performance under different asymmetric conditions is described

Medicovan (1962-06)

Published by: Medical College of Virginia, Feb. 1948-Aug. 1972; Virginia Commonwealth University, Sept. 1972-Feb. 1973.https://scholarscompass.vcu.edu/med/1124/thumbnail.jp

Predicting Court Cases Quantitatively

This article illustrates and systematically compares three methods for quantitatively predicting case outcomes. The three methods are correlation, regression, and discriminant analysis, all of which involve standard social science research techniques. Two prior articles have generated requests for a study dealing with the problems involved in handling a larger number of cases and predictive variables. The present article is also designed to provide such a study. It does not presuppose that the reader has read the earlier articles, although such a reading might help to clarify further some of the points made here. The cases used to illustrate the methods consist of 149 civil liberties cases decided by the United States Supreme Court from 1956 through 1960. The list of cases was obtained from a series of articles written by Sidney Ulmer and Glendon Schubert. Technical aspects have been eliminated from the body of this article, leaving a simple explanation that should be sufficient to enable the non-technical reader to employ the methods in his legal research

The effect of exposure conditions on the perceptual learning of a discrimination task

Thesis (Ed.D.)--Boston Universit