On the Multifractal Structure of Observed Internet Addresses

Presenter: Megan Walter – Computer and Information Science

Faculty Mentor(s): Reza Rejaie, Chris Misa

Session: (Virtual) Oral Panel—Inner Space and Internet

As a result of society’s increasing dependence on the internet, we observe an uptick in internet attacks and network management issues. However, the growing speed and volume of internet traffic makes finding portions of traffic responsible for creating problems difficult. Current approaches to classifying connections as harmful or benign tend to regard each connection independently of one another. However, the nature of IP addresses points to correlations between addresses located in similar parts of the IP address space. Understanding the structural characteristics of the IP address space could lead to novel ways to create network management algorithms that deal with aggregates of flows.

We examine the structure of observed IP addresses in network traffic collected from border routers at the University of Oregon. Previous work indicates that the characteristics of observed IPv4 address structures are consistent with a multifractal model. We work to solidify the existence of this multifractal structure and provide an initial contribution to the development of network security and management solutions that aggregate flows by IP address. We use a brand new method of multifractal analysis using the method of moments to produce an initial characterization of how observed IPv4 addresses relate to one another. We applied this process across traffic samples representing three different timescales, allowing us to look at the temporal dynamics of these multifractal characteristics.

Radiation Trapping in Alkali Atoms

Presenter: Samuel Karlson − Physics

Faculty Mentor(s): Brian Patterson

Session: (Virtual) Oral Panel—Inner Space and Internet

We used a Monte Carlo computer algorithm to simulate the effects of radiation trapping in a potassium vapor cell with nitrogen and helium buffer gases. Understanding the effects of radiation trapping is important in applications such as the creation of gas lasers or the validation of atomic models. For example, the impacts of radiation trapping are significant when scaling diode-pumped alkali lasers (DPAL) to high powers. Simulations were made for buffer gas pressures as high as 1000 torr and cell temperatures as high as 200°C. A variety of cell geometries was studied. We used experimental data to validate our simulations. In the experiment, a femtosecond laser pulse excited potassium atoms along the D2 absorption line and the resulting fluorescence was observed as a function of time. An exponential fit of these points determined the excited state lifetime. A comparison of the statistical model and experimental results will be discussed.

Analysis of RadioXenon Using Trap and Trace Analysis

Presenter(s): Piper Gray – Physics

Faculty Mentor(s): Michael Shaffer

Session: (Virtual) Oral Panel—Inner Space and Internet

This project examines the use of atom trap and trace analysis for measuring the proportion of radioactive Xenon isotopes to stable Xenon in an air sample. Radioactive Xenon is not naturally occurring, so the presence of radioactive Xenon indicates artificial nuclear fission activity. Xenon and its radioactive isotopes are typical by-products of all three major types of special nuclear material (SNM): plutonium, uranium-233, and uranium-235. It is also a by-product of nuclear reactors and medical applications. Each process produces radioactive Xenon at different concentrations, so it is essential to determine the exact proportion. The proposed method will trap individual atoms of Xenon using laser cooling and trapping technologies, and they will fluoresce as they relax from the excited state to the ground state. The frequency at which Xenon atoms are trapped and fluoresce is unique to specific isotopes and will be used to identify the atoms contained in an air sample. The laser frequencies which will trap the radioactive isotopes of Xenon are not yet identified. This project will determine these frequencies using atom trap and trace analysis (ATTA) assisted laser spectroscopy and scanning the laser across frequencies until the Xe radioisotope fluoresces. This process will augment the current methods and help determine the concentration of radioactive Xenon in the sample with greater precision.