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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.

168,694 papers · 148 categories

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53105158210 · Jun 202019922001200920172026
48 results for context trees

Bayesian framework uses context trees for efficient time series modeling.

problem Building flexible and interpretable mixture models for real-valued time series.
method Hierarchical Bayesian modelling with context trees and autoregressive models.
result The methods outperform state-of-the-art techniques on simulated and real-world experiments.

Bayesian context trees capture complex dependencies in categorical sequences.

problem Complex, long-range dependencies in categorical sequences are not well captured by simple models.
method Parsimonious Bayesian context trees with model-based agglomerative clustering for efficient inference.
result The proposed framework outperforms existing models on real-world data.

The profusion of online news articles makes it difficult to find interesting articles, a problem that can be assuaged by using a recommender system to bring the most relevant news stories to readers. However, news recommendation is challenging because the most relevant articles are often new content seen by few users. …

2013-03-04abs ↗pdf ↗

The paper uses tensor decompositions to improve neural network models for tree data.

problem Encoding structural knowledge from tree-structured data efficiently.
method Introduces new aggregation functions using Canonical and Tensor-Train decompositions.
result Proposed models outperform traditional methods on tree classification tasks.

Paper proposes a VB method for TS-SBP mixture models with reduced computational cost.

problem Efficiently learning tree-structured stick-breaking process mixture models.
method Utilizes Bayes coding algorithm for context tree models to calculate sums over all possible trees.
result Proposes a learning algorithm with less computational cost for TS-SBP mixture of Gaussians.

Bayesian Context Trees improve change-point detection in discrete data.

problem Detecting and segmenting change-points in discrete time series data.
method Bayesian Context Trees framework, Markov chain Monte Carlo sampling.
result Effective sampling from posterior distribution of change-points.

This paper proposes an online tree-based Bayesian approach for reinforcement learning. For inference, we employ a generalised context tree model. This defines a distribution on multivariate Gaussian piecewise-linear models, which can be updated in closed form. The tree structure itself is constructed using the cover tr…

2013-05-08abs ↗pdf ↗

WildWood improves Random Forest predictions using bootstrap out-of-bag samples.

problem Improving Random Forest predictions for supervised learning.
method Uses bootstrap out-of-bag samples to compute improved predictions by aggregating all possible subtrees with exponential weights.
result WildWood produces faster and more competitive predictions compared to other ensemble methods.

Bayesian Context Trees model improves financial time series forecasting.

problem Modeling and forecasting financial time series with volatility asymmetries.
method Hierarchical Bayesian framework for tree-based mixture models with AR/ARCH base models.
result BCT-X framework outperforms state-of-the-art techniques in forecasting accuracy and computational efficiency.

A contextual care protocol is used by a medical practitioner for patient healthcare, given the context or situation that the specified patient is in. This paper proposes a method to build an automated self-adapting protocol which can help make relevant, early decisions for effective healthcare delivery. The hybrid mode…

2018-11-15abs ↗pdf ↗

We show how neural models can be used to realize piece-wise constant functions such as decision trees. The proposed architecture, which we call locally constant networks, builds on ReLU networks that are piece-wise linear and hence their associated gradients with respect to the inputs are locally constant. We formally …

2019-09-30abs ↗pdf ↗

Regression trees learn gradients of differentiable functions.

problem Understanding gradients of differentiable functions using regression trees.
method Developed a method to estimate gradients of differentiable functions using regression trees and exposed quantities from tree learning libraries.
result Gradient estimates from regression trees can be used to improve predictive analysis and solve tasks in uncertainty quantification.

RNNs struggle with in-context retrieval, while Transformers excel.

problem In-context retrieval capability of RNNs.
method Theoretical analysis and experimental techniques (CoT, RAG, Transformer layer).
result Enhancing RNNs with techniques improves their in-context retrieval capability, closing the representation gap with Transformers.

The paper introduces a tensor-based approach to improve neural models' aggregation of structural context.

problem Sub-optimal use of simple aggregation functions in neural models for structured data.
method Tensor-based formulation and Tucker tensor decomposition to control parameter space size.
result Effective regulation of trade-off between expressivity, computational complexity, and generalisation.

The lack of interpretability remains a barrier to the adoption of deep neural networks. Recently, tree regularization has been proposed to encourage deep neural networks to resemble compact, axis-aligned decision trees without significant compromises in accuracy. However, it may be unreasonable to expect that a single …

2019-08-13abs ↗pdf ↗

Although adversarial examples and model robustness have been extensively studied in the context of linear models and neural networks, research on this issue in tree-based models and how to make tree-based models robust against adversarial examples is still limited. In this paper, we show that tree based models are also…

2019-02-27abs ↗pdf ↗

Deep learning improves tree species classification accuracy in imbalanced contexts.

problem Inaccurate tree species maps for large areas, especially in imbalanced contexts.
method Used deep learning models (including convolutional and attention-based) on Sentinel-2 multispectral satellite time series data.
result Deep learning models achieve higher accuracy and F1-macro scores compared to Random Forest in imbalanced contexts.

In the context of tree-search stochastic planning algorithms where a generative model is available, we consider on-line planning algorithms building trees in order to recommend an action. We investigate the question of avoiding re-planning in subsequent decision steps by directly using sub-trees as action recommender. …

2018-05-03abs ↗pdf ↗

It is well known that surface groups admit free and proper actions on finite products of infinite valence trees. In this note, we address the question of whether there can be a free and proper action on a finite product of bounded valence trees. We provide some obstructions and an arithmetic criterion for existence. Th…

2016-05-17abs ↗pdf ↗

The paper connects decision tree interpretability and robustness through separation.

problem Empirical observation of a connection between robustness and interpretability in decision trees.
method Investigation of the connection through decision trees and ll_{\infty}-perturbation robustness, proving bounds on tree size.
result First algorithm with guarantees on robustness, interpretability, and accuracy for decision trees.

New language model shows context length impacts generation quality and reasoning ability.

problem Analyzing the impact of context length and reasoning on autoregressive generation.
method Introduced synthetic hierarchical languages, used an exact k-gram ansatz, derived asymptotic predictions, and validated empirically.
result Reasoning models with limited context can generate sequences from the true language, improving exponentially over standard models.

We study the natural map eta between a group of binary planar trees whose leaves are labeled by elements of a free abelian group H and a certain group D(H) derived from the free Lie algebra over H. Both of these groups arise in several different topological contexts. The map eta is known to be an isomorphism over Q, bu…

2005-04-13abs ↗pdf ↗

Variable selection for high-dimensional linear models has received a lot of attention lately, mostly in the context of l1-regularization. Part of the attraction is the variable selection effect: parsimonious models are obtained, which are very suitable for interpretation. In terms of predictive power, however, these re…

2009-06-19abs ↗pdf ↗

Tree-based algorithm for functional data analysis reduces generalization error.

problem Classification and regression problems with functional data.
method Constrained convex optimization for weighted functional L2L^{2} space, multiple splitting rules, and weighted integral features.
result Reduces generalization error while maintaining interpretability.

New framework estimates staged tree models using hierarchical clustering on the probability simplex.

problem Estimating staged tree models with context-specific dependencies.
method Hierarchical clustering on the probability simplex, using simplex-based divergences and linkage methods.
result Total Variation divergence with Ward.D2 linkage produces staged trees with better model fit, structure recovery, and computational efficiency.

UnmaskingTrees improves tabular data imputation and generation using gradient-boosted decision trees.

problem Traditional methods outperform advanced deep learning techniques on tabular data imputation benchmarks.
method UnmaskingTrees employs gradient-boosted decision trees to incrementally unmask features for imputation and generation.
result UnmaskingTrees outperforms state-of-the-art methods on tabular imputation and generation benchmarks.

Data collection at a massive scale is becoming ubiquitous in a wide variety of settings, from vast offline databases to streaming real-time information. Learning algorithms deployed in such contexts must rely on single-pass inference, where the data history is never revisited. In streaming contexts, learning must also …

2012-01-26abs ↗pdf ↗

The study explores ends in coarse homotopy of proper geodesic spaces.

problem Understanding ends in coarse homotopy of proper geodesic spaces.
method Recontextualizing ends as a functor and proving properties of coarse path components.
result Existence of a natural surjection from coarse path components to ends, not always an injection.

This paper examines the stability of learned explanations for black-box predictions via model distillation with decision trees. One approach to intelligibility in machine learning is to use an understandable `student' model to mimic the output of an accurate `teacher'. Here, we consider the use of regression trees as a…

2018-08-22abs ↗pdf ↗

We explicate a number of notions of algebraic laminations existing in the literature, particularly in the context of an exact sequence 1HGQ11\to H\to G \to Q \to 1 of hyperbolic groups. These laminations arise in different contexts: existence of Cannon-Thurston maps; closed geodesics exiting ends of manifolds; dual to …

2015-06-26abs ↗pdf ↗

The paper introduces new Bayesian network classifiers for better classification accuracy.

problem Improving supervised classification accuracy using Bayesian network classifiers.
method Developed novel classes of generative classifiers based on staged tree models, extending Bayesian networks.
result Data-driven learning routines enhance the accuracy of the new classifiers.

This work is the first step towards a description of the Gromov boundary of the free factor graph of a free product, with applications to subgroup classification for outer automorphisms. We extend the theory of algebraic laminations dual to trees, as developed by Coulbois, Hilion, Lustig and Reynolds, to the context of…

2017-09-17abs ↗pdf ↗

Decision trees with binary splits are popularly constructed using Classification and Regression Trees (CART) methodology. For binary classification and regression models, this approach recursively divides the data into two near-homogenous daughter nodes according to a split point that maximizes the reduction in sum of …

2019-06-24abs ↗pdf ↗