Graph-to-Sequence Learning using Gated Graph Neural Networks

Many NLP applications can be framed as a graph-to-sequence learning problem. Previous work proposing neural architectures on this setting obtained promising results compared to grammar-based approaches but still rely on linearisation heuristics and/or standard recurrent networks to achieve the best performance. In this work, we propose a new model that encodes the full structural information contained in the graph. Our architecture couples the recently proposed Gated Graph Neural Networks with an input transformation that allows nodes and edges to have their own hidden representations, while tackling the parameter explosion problem present in previous work. Experimental results show that our model outperforms strong baselines in generation from AMR graphs and syntax-based neural machine translation.Comment: ACL 201

Exploring Prediction Uncertainty in Machine Translation Quality Estimation

Machine Translation Quality Estimation is a notoriously difficult task, which lessens its usefulness in real-world translation environments. Such scenarios can be improved if quality predictions are accompanied by a measure of uncertainty. However, models in this task are traditionally evaluated only in terms of point estimate metrics, which do not take prediction uncertainty into account. We investigate probabilistic methods for Quality Estimation that can provide well-calibrated uncertainty estimates and evaluate them in terms of their full posterior predictive distributions. We also show how this posterior information can be useful in an asymmetric risk scenario, which aims to capture typical situations in translation workflows.Comment: Proceedings of CoNLL 201

Stereoselective intramolecular Michael addition reactions of pyrrole and their application to natural product syntheses

Chapter one; “(-)-Rhazinilam and (-)-Rhazinal: Alkaloids with Anti-mitotic Properties Derived from Kopsia teoi”, provides the background information behind the motives that initiated this research project. The plant alkaloid (-)-rhazinilam [(-)-1] and its naturally-occurring derivative (-)-rhazinal [(-)-13] both exhibit potent anti-mitotic activities and, as such, are interesting targets for total synthesis. Chapter one is a review of the literature regarding these two compounds and discusses the occurrence, proposed biosynthetic origins, structural elucidation and biological activites of compound (-)-1 and that of its analogues including alkaloid (-)-13. ... ¶ Chapter two; “Investigating Asymmetric Induction in the Intramolecular Michael Addition of pyrrole to N-Tethered Acrylates and Related Species”, introduces the model study used to direct research towards achieving the goal of asymmetric induction in the title process. The model is a somewhat simplified version of the original process used in the total synthesis of compound (-)-13 involving cyclisation of the C2 of pyrrole onto an N-tethered and ?-monosubstituted Michael acceptor, to produce a tertiary-carbon stereogenic centre. ... ¶ Chapter three “An Enantioselective Total Synthesis of the Alkaloid (-)-Rhazinal: An Anti-mitotic Agent Isolated from Kopsia teoi.”, focuses on the application of methodology developed in the previous chapter, to the original goal of inducing asymmetry in the intramolecular Michael addition reaction, involving cyclisation of the C2 of pyrrole onto an N-tethered and ?,?-disubstituted acrylate to produce a quaternary-carbon stereogenic centre. ...¶ Chapter four “Extending the Reaction Manifold to the Syntheses of Related Natural Products: A Formal Total Synthesis of (+)-Aspidospermidine and Syntheses of (-)-Rhazinilam and (-)-Leuconolam from (-)-Rhazinal”, describes three extensions to the reaction manifold used in the enantioselective total synthesis of alkaloid (-)-13: ... ¶ Chapter five contains the experimental procedures and characterisation data associated with compounds described in chapters two to four

Men and ARVs: how does being a man affect access to antiretroviral therapy in South Africa? an investigation among Xhosa-Speaking men in Khayelitsha

This paper aims to improve understanding of the nature and causes of barriers to accessing ARV treatment that affect men and result in their low rates of clinic attendance. The findings are intended to provide a direction for policy in the implementation of the South African government’s Comprehensive Plan for HIV/AIDS. Through a combination of semi-structured interviews and focus groups, experiences and opinions were collected from men living with HIV/AIDS and health workers working at an ARV treatment clinic in Khayelitsha, South Africa. Using an interpretivist approach, and informed by theories of social constructionism, an understanding was formed taking into consideration the complex nature of their realities. Thematic content analysis was selected as the best way of handling a large volume of material spanning a broad range of issues. Only by attempting to understand the nature of Xhosa culture and what it means to be a Xhosa man, was it possible to comprehend the material. Barriers to access manifested themselves at several levels of experience. Stigma, gender issues, preference of traditional medicine, cultural ideals of manhood, and several practical issues, all influenced a man’s ability to acknowledge his HIV status or to seek help. Suggestions to address these problems were made throughout the paper, founded on a combination of interviewees’ opinions and researcher’s analysis. These suggestions are important to acknowledge before a national ARV programme becomes fully implementational

A Neural Circuit Model for Prospective Control of Interceptive Reaching

Two prospective controllers of hand movements in catching -- both based on required velocity control -- were simulated. Under certain conditions, this required velocity controlled to overshoots of the future interception point. These overshoots were absent in pertinent experiments. To remedy this shortcoming, the required velocity model was reformulated in terms of a neural network, the Vector Integration To Endpoint model, to create a Required Velocity Integration To Endpoint modeL Addition of a parallel relative velocity channel, resulting in the Relative and Required Velocity Integration To Endpoint model, provided a better account for the experimentally observed kinematics than the existing, purely behavioral models. Simulations of reaching to intercept decelerating and accelerating objects in the presence of background motion were performed to make distinct predictions for future experiments.Vrije Universiteit (Gerrit-Jan van Jngen-Schenau stipend of the Faculty of Human Movement Sciences); Royal Netherlands Academy of Arts and Sciences; Defense Advanced Research Projects Agency and Office of Naval Research (N00014-95-1-0409

Moor Movement: Automated Docking on Drought-Stricken Reservoirs

Moor Movement establishes a mechanized docking system for unpredictable shoreline fluctuations on inland lakes and reservoirs. Due to climate change and warmer global temperatures, the threat of ocean level rise has initiated massive proposals to address the interface between ocean and man-made infrastructure. While this is a monumental problem, ocean level rise is not the only immediate threat. The recently declared emergency drought conditions in California are finally bringing attention to inland lakes and reservoirs. While ocean levels might rise 2-7 feet in 100 years, a lake could drop 100 feet in 5 years. What happens to access roads, marinas, docks, beaches, and other facilities that were once “waterfront?” This project specifically models as a recreational demonstration on Boulder Beach, Lake Mead, where water levels are 149 feet low. Boulder Beach hosts around a million visitors and recreational enthusiasts from Las Vegas and surrounding communities every year

High Frequency Trading: Perceptions Regarding Volatility and Regulation

Although high frequency trading (HFT) makes up a large portion of day to day trading activity in US and global markets, Khashanah and colleagues (2014) found that nearly half of academic and business industry professionals feel that HFT provides an unfair advantage relative to other market participants, and that a majority of industry professionals share concerns that HFT increases volatility in markets. This creates an environment wherein there are increasing calls by various groups for increased regulation of HFT, and the same study by Khashanah et al (2014) finds that 59% of academics and 46% of industry professionals are of this opinion. The current study was designed to further examine perceptions of HFT, particularly with regards to its effects on volatility and further regulation, among a younger generation of respondents. By replicating the survey distributed by Khashanah and colleagues, this study aims to shed light on the opinions business students hold regarding HFT and draw comparisons between the industry professionals and academics and the results garnered here. Participants were asked to respond to a twelve question survey that asked for opinions about liquidity, price discovery, market crashes, and then respond to what they think an appropriate level of regulation for HFT should be. A Poisson regression analysis model was utilized in order to ascertain certain underlying trends in the data, and found correlations between major, age, and financial experience with negative perceptions of HFT