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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,742 papers · 148 categories

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371013 · Nov 201819922001200920172026
48 results for Brazilian hospitals

Machine learning improves early detection of patient deterioration in Brazilian hospitals.

problem Challenges in recognizing clinical deterioration in hospital settings.
method Application of machine learning to analyze EHR data from multiple hospitals.
result Machine learning models outperformed traditional protocols by 25 percentage points in AUC.

This paper calculates risk-dependent centrality of Brazilian stocks, showing rankings vary with external risk and crisis events.

problem Understanding asset rankings in the Brazilian stock market under varying external risks.
method Computed risk-dependent centrality (RDC) for Brazilian stocks traded from 2008 to 2020, analyzing volatility and returns.
result Asset rankings based on RDC vary with external risk and crisis events, with higher volatility in crisis periods.

Deep learning outperforms Black-Scholes in Brazilian Petrobras option pricing.

problem Improving option pricing accuracy for Petrobras stocks.
method Trained deep residual networks using a custom loss function with historical data.
result Deep learning achieved a 64.3% reduction in mean absolute error compared to Black-Scholes.

We investigate the Brazilian personal income distribution using data from National Household Sample Survey (PNAD), an annual research available by the Brazilian Institute of Geography and Statistics (IBGE). It provides general characteristics of the country's population. Using PNAD data background we also confirm the e…

2017-09-19abs ↗pdf ↗

Geometric Brownian motion simulates stock prices for Brazilian small caps index.

problem Simulating stock prices for the Brazilian small caps index.
method Used geometric Brownian motion to simulate stock prices of Brazilian small caps index using historical data.
result Simulated prices better for portfolios with higher returns, lower risks, and higher Sharpe Indexes.

Bayesian models forecast COVID-19 hospitalizations at single sites.

problem Forecasting daily COVID-19 hospitalizations at a single hospital.
method Hierarchical Bayesian models with generalized Poisson likelihood and autoregressive/Gaussian process latent processes.
result Demonstrated superior performance compared to baselines in public datasets.

Natural language processing improves COVID-19 hospitalization identification.

problem Identifying patients hospitalized due to COVID-19 among those with positive SARS-CoV-2 tests.
method Used natural language processing on provider notes and structured EHR data elements to create classification algorithms.
result Classification algorithms using provider notes outperformed those using only structured EHR data elements, with AUROC of 0.894 compared to 0.841.

Adversarial method improves pneumonia classifier's performance across hospitals.

problem Robust classification of pneumonia from chest radiographs across different hospitals.
method Adversarial optimization to learn models invariant to confounders.
result Improved out-of-hospital generalization performance compared to baselines.

AlphaX uses AI to outperform Brazilian stock market benchmarks.

problem AI strategies often overperform in backtests but underperform in real markets due to lookahead bias.
method Controlled simulations to mitigate lookahead bias, using Value Investing principles.
result AlphaX strategy outperforms major benchmarks and technical indicators.

We analyze expenditure patterns of discretionary funds by Brazilian congress members. This analysis is based on a large dataset containing over 77 million expenses made publicly available by the Brazilian government. This dataset has, up to now, remained widely untouched by machine learning methods. Our main contribut…

2018-11-29abs ↗pdf ↗

Develops a three-currency HJM framework for Brazilian credit markets, finding significant credit spread differences between indexed segments.

problem Identifies and quantifies differences in corporate credit spreads between two parallel segments of the Brazilian bond market.
method Uses a Heath-Jarrow-Morton framework to model corporate credit as a separate economy, linking it to nominal and real economies through synthetic rates.
result Empirically finds a 640 basis point average difference in credit spreads between CDI-indexed and IPCA-indexed segments, stable through market cycles.

This book was intended to serve as supporting material for a mini-course on web geometry delivered at the 27th Brazilian Mathematical Colloquium which took place at IMPA in the last week of July 2009.

2011-07-04abs ↗pdf ↗

The paper uses SHAP for interpreting machine learning models in hospital data.

problem Interpreting machine learning models in healthcare.
method SHAP for feature importance and feature packing techniques.
result SHAP provides better interpretability of machine learning models in healthcare.

FUALA improves Federated Learning for EHR data, enhancing model uncertainty.

problem Applying ML to EHR data while maintaining privacy and accuracy.
method FUALA embeds uncertainty in federated learning, using ensembling and averaging.
result FUALA outperforms FedAvg on out-of-distribution data in EHR model predictions.

These are lecture notes on scale calculus and M-polyfolds written for a graduate course at UNICAMP March-June 2018 and an advanced mini-course given during the biannual meeting of Brazilian mathematicians, CBM-32, at IMPA in August 2019.

2019-08-04abs ↗pdf ↗

This paper discusses the empirical validity of Goodwin's (1967) macroeconomic model of growth with cycles by assuming that the individual income distribution of the Brazilian society is described by the Gompertz-Pareto distribution (GPD). This is formed by the combination of the Gompertz curve, representing the overwhe…

2013-01-07abs ↗pdf ↗

In this paper, we explore and detail our experiments in a high-dimensionality, multi-class image classification problem often found in the automatic recognition of Sign Languages. Here, our efforts are directed towards comparing the characteristics, advantages and drawbacks of creating and training Support Vector Machi…

2012-10-28abs ↗pdf ↗

Trans-GLMC tackles source heterogeneity in transfer learning for structured clusters.

problem Source heterogeneity makes it hard to use multiple related auxiliary sources effectively.
method Trans-GLMC constructs clusters of sources, then combines global fusion, within-cluster refinement, and target debiasing.
result Improves facility-specific prediction and identifies interpretable communities of hospitals with mutual transferability.

Optimal income crossover found using particle swarm optimization.

problem Determining the crossover point between two income distributions.
method Particle swarm optimization for finding crossover income, temperature, and Pareto index.
result Optimization method finds boundaries of two income distributions.

New scalable method balances hospital profit status and heart attack outcomes.

problem Balancing covariate distributions and minimizing weight dispersion in large datasets.
method Combines kernel basis expansion and convex optimization for efficient and flexible weighting.
result For-profit hospitals use interventional cardiology similarly to other hospitals but have higher mortality and readmission rates.

A large volume of research has considered the creation of predictive models for clinical data; however, much existing literature reports results using only a single source of data. In this work, we evaluate the performance of models trained on the publicly-available eICU Collaborative Research Database. We show that cr…

2018-12-06abs ↗pdf ↗

Study on supply chain networks using wire transfers in Brazil.

problem Understanding economic integration and specialization in Brazilian cities.
method Constructed a directed and weighted network of wire transfers between cities, analyzed centrality measures, and used econometric analysis.
result Disassortative mixing pattern in trade network, stronger after recession, and impact of court efficiency on economic transactions.

This work proposes a student-teacher network for predicting hospital admission locations.

problem Accurate prediction of hospital admission locations to optimize resource allocation.
method Reinforcement learning approach where a teacher network selects data batches for a student network.
result The approach outperforms state-of-the-art methods on tabular data and image recognition.

Estimates funding impact from an algorithmic relief rule, finding little effect on hospital activities.

problem Evaluating the impact of algorithmic policy decisions.
method Developed a treatment-effect estimator using algorithmic decisions as instruments.
result Funding from an algorithmic relief rule had little effect on COVID-19-related hospital activities.