Tracing Transactions Across Cryptocurrency Ledgers

One of the defining features of a cryptocurrency is that its ledger, containing all transactions that have evertaken place, is globally visible. As one consequenceof this degree of transparency, a long line of recent re-search has demonstrated that even in cryptocurrenciesthat are specifically designed to improve anonymity it is often possible to track money as it changes hands,and in some cases to de-anonymize users entirely. With the recent proliferation of alternative cryptocurrencies, however, it becomes relevant to ask not only whether ornot money can be traced as it moves within the ledgerof a single cryptocurrency, but if it can in fact be tracedas it moves across ledgers. This is especially pertinent given the rise in popularity of automated trading platforms such as ShapeShift, which make it effortless to carry out such cross-currency trades. In this paper, weuse data scraped from ShapeShift over a thirteen-monthperiod and the data from eight different blockchains to explore this question. Beyond developing new heuristics and creating new types of links across cryptocurrency ledgers, we also identify various patterns of cross-currency trades and of the general usage of these platforms, with the ultimate goal of understanding whetherthey serve a criminal or a profit-driven agenda.Comment: 14 pages, 13 tables, 6 figure

A shooting argument approach to a sharp type solution for nonlinear degenerate Fisher-KPP equations

In this paper we prove the existence and uniqueness of a travelling-wave solution of sharp type for the degenerate (at u = 0) parabolic equation $u_1 = [D(u)u_x]_x + g(u)$ where D is a strictly increasing function and g is a function which generalizes the kinetic part of the classical Fisher-KPP equation. The original problem is transformed into the proper travelling-wave variables, and then a shooting argument is used to show the existence of a saddle-saddle heteroclinic trajectory for a critical value, c*>0, of the speed c of an autonomous system of ordinary differential equations. Associated with this connection is a sharp-type solution of the nonlinear partial differential equation

An Empirical Analysis of Privacy in Cryptocurrencies

Cryptocurrencies have emerged as an important technology over the past decade and have, undoubtedly, become blockchain’s most popular application. Bitcoin has been by far the most popular out of the thousands of cryptocurrencies that have been created. Some of the features that made Bitcoin such a fascinating technology include its transactions being made publicly available and permanently stored, and the ability for anyone to have access. Despite this transparency, it was initially believed that Bitcoin provides anonymity to its users, since it allowed them to transact using a pseudonym instead of their real identity. However, a long line of research has shown that this initial belief was false and that, given the appropriate tools, Bitcoin transactions can indeed be traced back to the real-life entities performing them. In this thesis, we perform a survey to examine the anonymity aspect of cryptocurrencies. We start with early works that made first efforts on analysing how private this new technology was. We analyse both from the perspective of a passive observer with eyes only to the public immutable state of transactions, the blockchain, as well as from an observer who has access to network layer information. We then look into the projects that aimed to enhance the anonymity provided in cryptocurrencies and also analyse the evidence of how much they succeeded in practice. In the first part of our own contributions we present our own take on Bitcoin’s anonymity, inspired by the research already in place. We manage to extend existing heuristics and provide a novel methodology on measuring the confidence we have in our anonymity metrics, instead of looking into the issue from a binary perspective, as in previous research. In the second part we provide the first full-scale empirical work on measuring anonymity in a cryptocurrency that was built with privacy guarantees, based on a very well established cryptography, Zcash. We show that just building a tool which provides anonymity in theory is very different than the privacy offered in practice once users start to transact with it. Finally, we look into a technology that is not a cryptocurrency itself but is built on top of Bitcoin, thus providing a so-called layer 2 solution, the Lightning network. Again, our measurements showed some serious privacy concerns of this technology, some of which were novel and highly applicable

Crafting a 21st Century United States Patent and Trademark Office

Good morning. It is a privilege to be here representing the United States Patent and Trademark Office (USPTO). I want to thank the Missouri Law Review for the invitation and for hosting me here today. Moreover, I want to commend the University of Missouri for convening this important conference. These are critical topics, and today I want to focus on the key role the USPTO will play in shaping patent protections in the future. But let me first congratulate the members from the Federal Circuit who are present today for thirty years of excellence in addressing the most fundamental of considerations within patent policy. Your ongoing engagement of IP issues is pivotal to our ability to work together as a community and promote a strong, balanced patent system. And your efforts not only work to safeguard generation-changing ideas in the marketplace, but on the larger scale they promote growth and new market opportunities for our country

Predicting the On-Study Relapse Rate for Multiple Sclerosis Patients in Clinical Trials

Background: The annual relapse rate has been commonly used as a primary efficacy endpoint in phase III multiple sclerosis (MS) clinical trials. The aim of this study was to determine the relative contribution of different possible prognostic factors available at baseline to the on-study relapse rate in MS. Methods: A total of 821 patients from the placebo arms of the Sylvia Lawry Centre for Multiple Sclerosis Research (SLCMSR) database were available for this analysis. The univariate relationships between on-study relapse rate and the baseline demographic, clinical, and MRI-based predictors were assessed. The multiple relationships were then examined using a Poisson regression model. Two predictor subsets were selected. Subset 1 included age at disease onset, disease duration, gender, Expanded Disability Status Scale (EDSS) at baseline, number of relapses in the last 24 months prior to baseline, and the disease course (RR and SP). Subset 2 consisted of Subset 1 plus gadolinium enhancement status in MRI. The number of patients for developing the models with no missing values was 727 for Subset 1 and 306 for Subset 2. Results:The univariate relationships show that the on-study relapse rate was higher for younger and for female patients, for RR patients than for SP patients, and for patients with positive enhancement status at entry (Wilcoxon test, p<0.05). A higher on-study relapse rate was associated with a shorter disease duration, lower entry EDSS, more pre-study relapses and more enhancing lesions in T1 at entry. The fitted Poisson model shows that disease duration (estimate=-0.02) and previous relapse number (estimate=0.59 for 1, 0.91 for 2 and 1.45 for 3 or more relapses vs 0 relapse) remain. We were able to confirm these findings in a second, independent dataset. Conclusions: The relapse number prior to entry into clinical trials together with disease duration are the best predictors for the on-study relapse rate. Disease course and gadolinium enhancement status, given the other covariates, have no significant influence on the on-study relapse rate

Assessment of Microplastics in Southeastern Florida Forage Fishes

Microplastics threaten the health of numerous marine organisms at all trophic levels. Currently, the topic is well studied among larger predators such as marine birds, dolphins, pelagic fishes, and even herbivorous organisms such as manatees. However, knowledge of microplastics present in organisms at lower trophic levels is poorly understood. The aim of this study was to assess the presence of microplastics in lower trophic level forage fishes. To gain a clear depiction of microplastics in the forage fishes of South Florida, four locations were sampled. These locations were classified into two categories, urban (Port Everglades and Northern Biscayne Bay) and non-urban (Islamorada and Marathon, in the Florida Keys). Five species were sampled: Striped Mullet, Scaled Sardine, Needlefish, Pinfish, and Irish Mojarra. Every sampled fish except one (n= 248) had microplastics within their systems, with a total of 2,126 pieces found. There was no significant difference in microplastics concentration among forage fish species. However, location had a significant effect on the frequency of microplastics found within the sampled fishes, with Northern Biscayne Bay being greater compared to the other three sample locations. There was no significant difference in microplastic frequency amongst the three feeding habits within the five sampled species. However, as Redfin Needlefish and Pinfish matured, an increase in microplastic frequency was observed. With a frequency of 99.6% of microplastic contamination within the sampled fishes, significant conservation efforts should be warranted