Africa
Learning-based estimation of dielectric properties and tissue density in head models for personalized radio-frequency dosimetry
Rashed, Essam A., Diao, Yinliang, Hirata, Akimasa
Radio-frequency dosimetry is an important process in human safety and for compliance of related products. Recently, computational human models generated from medical images have often been used for such assessment, especially to consider the inter-variability of subjects. However, the common procedure to develop personalized models is time consuming because it involves excessive segmentation of several components that represent different biological tissues, which limits the inter-variability assessment of radiation safety based on personalized dosimetry. Deep learning methods have been shown to be a powerful approach for pattern recognition and signal analysis. Convolutional neural networks with deep architecture are proven robust for feature extraction and image mapping in several biomedical applications. In this study, we develop a learning-based approach for fast and accurate estimation of the dielectric properties and density of tissues directly from magnetic resonance images in a single shot. The smooth distribution of the dielectric properties in head models, which is realized using a process without tissue segmentation, improves the smoothness of the specific absorption rate (SAR) distribution compared with that in the commonly used procedure. The estimated SAR distributions, as well as that averaged over 10-g of tissue in a cubic shape, are found to be highly consistent with those computed using the conventional methods that employ segmentation.
A Deep Reinforcement Learning based Approach to Learning Transferable Proof Guidance Strategies
Crouse, Maxwell, Whitehead, Spencer, Abdelaziz, Ibrahim, Makni, Bassem, Cornelio, Cristina, Kapanipathi, Pavan, Pell, Edwin, Srinivas, Kavitha, Thost, Veronika, Witbrock, Michael, Fokoue, Achille
Traditional first-order logic (FOL) reasoning systems usually rely on manual heuristics for proof guidance. We propose TRAIL: a system that learns to perform proof guidance using reinforcement learning. A key design principle of our system is that it is general enough to allow transfer to problems in different domains that do not share the same vocabulary of the training set. To do so, we developed a novel representation of the internal state of a prover in terms of clauses and inference actions, and a novel neural-based attention mechanism to learn interactions between clauses. We demonstrate that this approach enables the system to generalize from training to test data across domains with different vocabularies, suggesting that the neural architecture in TRAIL is well suited for representing and processing of logical formalisms.
Interpreting Verbal Irony: Linguistic Strategies and the Connection to the Type of Semantic Incongruity
Ghosh, Debanjan, Musi, Elena, Upasani, Kartikeya, Muresan, Smaranda
Human communication often involves the use of verbal irony or sarcasm, where the speakers usually mean the opposite of what they say. To better understand how verbal irony is expressed by the speaker and interpreted by the hearer we conduct a crowdsourcing task: given an utterance expressing verbal irony, users are asked to verbalize their interpretation of the speaker's ironic message. We propose a typology of linguistic strategies for verbal irony interpretation and link it to various theoretical linguistic frameworks. We design computational models to capture these strategies and present empirical studies aimed to answer three questions: (1) what is the distribution of linguistic strategies used by hearers to interpret ironic messages?; (2) do hearers adopt similar strategies for interpreting the speaker's ironic intent?; and (3) does the type of semantic incongruity in the ironic message (explicit vs. implicit) influence the choice of interpretation strategies by the hearers?
Artificial Intelligence (AI) In Fintech Market Consumption Volume, Rising Trends and Growth Forecast 2019-2025 - Galus Australis
Artificial Intelligence (AI) In Fintech Market report provides the past, present and future industry trends and the forecast information related to the expected Artificial Intelligence (AI) In Fintech Market sales revenue, growth, demand, and supply scenario. It offers in-depth data, improves variations of the worldwide Artificial Intelligence (AI) In Fintech Market to help you in deciding the final strategy. It features far-reaching information in terms of changing market dynamics, manufacturing trends, structural changes in the market, and the latest developments. Market Overview: The report begins with this section where product overview and highlights of product and application segments of the global Artificial Intelligence (AI) In Fintech Market are provided. Highlights of the segmentation study include price, revenue, sales, sales growth rate, and market share by product.
Success Stories of Reinforcement Learning
In September 2018, I got the opportunity to attend the Deep Learning Indaba conference that was held in Stellenbosch University, South Africa. Deep Learning Indaba was formed with an aim to strengthen African Machine Learning as well as to increase African participation and contribution to the advances in artificial intelligence and machine learning, and address issues of diversity in these fields of science. One of the lectures that I really enjoyed was on Success Stories of Reinforcement Learning where we got introduced to reinforcement learning as well as how it was used to build some pretty awesome computer programs. This lecture was presented by David Silver. Professor David Silver Leads the reinforcement learning research group at DeepMind which is an AI company based in London that was acquired by Google in 2014.
InsurTech_2019-11-01_21-49-01.xlsx
The graph represents a network of 2,908 Twitter users whose tweets in the requested range contained "InsurTech", or who were replied to or mentioned in those tweets. The network was obtained from the NodeXL Graph Server on Saturday, 02 November 2019 at 04:50 UTC. The requested start date was Friday, 01 November 2019 at 00:01 UTC and the maximum number of tweets (going backward in time) was 5,000. The tweets in the network were tweeted over the 3-day, 3-hour, 57-minute period from Monday, 28 October 2019 at 20:02 UTC to Thursday, 31 October 2019 at 23:59 UTC. Additional tweets that were mentioned in this data set were also collected from prior time periods.
Long-range Event-level Prediction and Response Simulation for Urban Crime and Global Terrorism with Granger Networks
Li, Timmy, Huang, Yi, Evans, James, Chattopadhyay, Ishanu
Large-scale trends in urban crime and global terrorism are well-predicted by socio-economic drivers, but focused, event-level predictions have had limited success. Standard machine learning approaches are promising, but lack interpretability, are generally interpolative, and ineffective for precise future interventions with costly and wasteful false positives. Here, we are introducing Granger Network inference as a new forecasting approach for individual infractions with demonstrated performance far surpassing past results, yet transparent enough to validate and extend social theory. Considering the problem of predicting crime in the City of Chicago, we achieve an average AUC of ~90\% for events predicted a week in advance within spatial tiles approximately $1000$ ft across. Instead of pre-supposing that crimes unfold across contiguous spaces akin to diffusive systems, we learn the local transport rules from data. As our key insights, we uncover indications of suburban bias -- how law-enforcement response is modulated by socio-economic contexts with disproportionately negative impacts in the inner city -- and how the dynamics of violent and property crimes co-evolve and constrain each other -- lending quantitative support to controversial pro-active policing policies. To demonstrate broad applicability to spatio-temporal phenomena, we analyze terror attacks in the middle-east in the recent past, and achieve an AUC of ~80% for predictions made a week in advance, and within spatial tiles measuring approximately 120 miles across. We conclude that while crime operates near an equilibrium quickly dissipating perturbations, terrorism does not. Indeed terrorism aims to destabilize social order, as shown by its dynamics being susceptible to run-away increases in event rates under small perturbations.
Supervised level-wise pretraining for recurrent neural network initialization in multi-class classification
Ienco, Dino, Interdonato, Roberto, Gaetano, Raffaele
Recurrent Neural Networks (RNNs) can be seriously impacted by the initial parameters assignment, which may result in poor generalization performances on new unseen data. With the objective to tackle this crucial issue, in the context of RNN based classification, we propose a new supervised layer-wise pretraining strategy to initialize network parameters. The proposed approach leverages a data-aware strategy that sets up a taxonomy of classification problems automatically derived by the model behavior. To the best of our knowledge, despite the great interest in RNN-based classification, this is the first data-aware strategy dealing with the initialization of such models. The proposed strategy has been tested on four benchmarks coming from two different domains, i.e., Speech Recognition and Remote Sensing. Results underline the significance of our approach and point out that data-aware strategies positively support the initialization of Recurrent Neural Network based classification models.
Inferring Coordination Strategies from Time Series of Movement Data
Amornbunchornvej, Chainarong, Berger-Wolf, Tanya
How do groups of individuals achieve consensus in movement decisions? Do individuals follow their friends, the one predetermined leader, or whomever just happens to be nearby? To address these questions computationally, we formalize Coordination Strategy Inference Problem. In this setting, a group of multiple individuals moves in a coordinated manner towards a target path. Each individual uses a specific strategy to follow others (e.g. nearest neighbors, pre-defined leaders, preferred friends). Given a set of time series that includes coordinated movement and a set of candidate strategies as inputs, we provide the first methodology (to the best of our knowledge) to infer the set of strategies that each individual uses to achieve movement coordination at the group level. We evaluate and demonstrate the performance of the proposed framework by predicting the direction of movement of an individual in a group in both simulated datasets as well as two real-world datasets: a school of fish and a troop of baboons. Moreover, since there is no prior methodology for inferring individual-level strategies, we compare our framework with the state-of-the-art approach for the task of classification of group-level-coordination models. The results show that our approach is highly accurate in inferring the correct strategy in simulated datasets even in complicated mixed strategy settings, which no existing method can infer. In the task of classification of group-level-coordination models, our framework performs better than the state-of-the-art approach in all datasets. Animal data experiments show that fish, as expected, follow their neighbors, while baboons have a preference to follow specific individuals. Our methodology generalizes to arbitrary time series data of real numbers, beyond movement data.
Assessing Social and Intersectional Biases in Contextualized Word Representations
Tan, Yi Chern, Celis, L. Elisa
Social bias in machine learning has drawn significant attention, with work ranging from demonstrations of bias in a multitude of applications, curating definitions of fairness for different contexts, to developing algorithms to mitigate bias. In natural language processing, gender bias has been shown to exist in context-free word embeddings. Recently, contextual word representations have outperformed word embeddings in several downstream NLP tasks. These word representations are conditioned on their context within a sentence, and can also be used to encode the entire sentence. In this paper, we analyze the extent to which state-of-the-art models for contextual word representations, such as BERT and GPT-2, encode biases with respect to gender, race, and intersectional identities. Towards this, we propose assessing bias at the contextual word level. This novel approach captures the contextual effects of bias missing in context-free word embeddings, yet avoids confounding effects that underestimate bias at the sentence encoding level. We demonstrate evidence of bias at the corpus level, find varying evidence of bias in embedding association tests, show in particular that racial bias is strongly encoded in contextual word models, and observe that bias effects for intersectional minorities are exacerbated beyond their constituent minority identities. Further, evaluating bias effects at the contextual word level captures biases that are not captured at the sentence level, confirming the need for our novel approach.