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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.

169,051 papers · 148 categories

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171342512683 · Jun 202019922001200920182026
48 results for Extreme State Aggregation (ESA)

This work expands state-action aggregation methods for non-Markovian environments.

problem Real-world problems with large state and action spaces are not tractable with existing methods.
method Expands Extreme State Aggregation (ESA) framework to non-Markovian homomorphisms and relaxes policy uniformity.
result Near-optimal performance is guaranteed even for non-Markovian homomorphisms.

Early-stopped aggregation improves computational efficiency in adaptive statistical inference.

problem Computational inefficiency in model selection and aggregation for adaptive inference.
method Early-stopped aggregation (ESA) framework: compute only a few simpler models using early-stopping criteria.
result ESA achieves optimal adaptive contraction rates in variational Bayes and frequentist settings.

The paper calculates VaR and CTE for extreme and aggregate risks using FGM copula.

problem Estimating risk measures for extreme and aggregate risks of dependent and independent markets.
method Used FGM copula to model dependence, exponential and pareto distributions for marginal risks.
result Effect of dependency on VaR and CTE of extreme and aggregate risks analyzed.

Paper introduces weak comonotonicity for more realistic extreme dependence scenarios.

problem Overly restrictive classical comonotonicity in various practical problems.
method Introduces weak comonotonicity and provides necessary and sufficient conditions for optimization problems.
result Weak comonotonicity is sufficient for maximizing Value-at-Risk aggregation and necessary for Expected Shortfall aggregation.

We study the problem of rank aggregation: given a set of ranked lists, we want to form a consensus ranking. Furthermore, we consider the case of extreme lists: i.e., only the rank of the best or worst elements are known. We impute missing ranks by the average value and generalise Spearman's ρto extreme ranks. Our main …

2014-10-16abs ↗pdf ↗

Paper tackles learning win-win solutions in aggregation systems.

problem Learning approximate equilibrium solutions in aggregation systems to keep suppliers.
method Multi-Agent Reinforcement Learning (MARL) with variance reduction mechanism.
result Approach reduces value variance and moves joint solution closer to Nash Equilibrium.

Paper proposes an algorithm to estimate state aggregation from Markov transition data.

problem Estimating probabilistic aggregation map from system's trajectory.
method Two-step algorithm: spectral decomposition and linear transformation of singular vectors.
result Sharp error bounds for estimating aggregation and disaggregation distributions.

New bounds for quantile aggregation unify and clarify existing methods.

problem Analytical bounds for quantile aggregation with dependence uncertainty.
method Using inf-convolution of quantile-based risk measures, establish new analytical bounds called convolution bounds.
result Convolution bounds are the best available and provide sharp results in many cases.

Optimized Q-learning reduces regret in state-aggregated MDPs.

problem Reducing regret in reinforcement learning with state aggregation.
method Optimistic Q-learning applied to fixed-horizon episodic MDPs with aggregated states.
result Regret bound of ildeO(H5MK+εHK) ilde{\mathcal{O}}(\sqrt{H^5 M K} + εHK), independent of states and actions.

New aggregation method improves GNN robustness to structural perturbations.

problem Graph Neural Networks (GNNs) are vulnerable to adversarial attacks that manipulate graph structure.
method Proposes a robust aggregation function with a breakdown point of 0.5, inspired by robust statistics.
result Improves GNN robustness by a factor of 3 on Cora ML and 5.5 on Citeseer, and 8 for low-degree nodes.

Paper finds robust ΛΛ-quantiles equal to extremal distributions.

problem Investigating robust models for ΛΛ-quantiles with partial loss information.
method Extending classical quantiles using ΛΛ-quantiles and applying results from robust quantiles.
result Robust ΛΛ-quantiles equal to ΛΛ-quantiles of extremal distributions.

FLANDERS detects and blocks extreme model poisoning in federated learning.

problem Resilience against large-scale model poisoning attacks in federated learning.
method FLANDERS treats client updates as matrix-valued time series and identifies outliers using autoregressive forecasting.
result FLANDERS significantly improves robustness in federated learning across various attacks.

Aggregated variables can mask causal effects, turning unconfounded into confounded relations.

problem Aggregated variables can mask causal effects, leading to paradoxical confounding.
method Analysis of how aggregated variables can change the definition of causality and the feasibility of causal relations.
result Macro causal relations are defined by micro states, not just aggregated variables.

We study the topological properties of the multinetwork of commodity-specific trade relations among world countries over the 1992-2003 period, comparing them with those of the aggregate-trade network, known in the literature as the international-trade network (ITN). We show that link-weight distributions of commodity-s…

2009-08-13abs ↗pdf ↗

Policy gradient methods with aggregated states can achieve better performance than approximate policy iteration.

problem Approximation errors in policy and value function approximations.
method State-aggregated representations and policy gradient methods.
result Policy gradient methods can achieve a per-period regret bounded by ε, while approximate policy iteration and value iteration have a higher regret.

Turbo-Aggregate reduces secure aggregation time from quadratic to nearly linear.

problem Quadratic overhead in secure model aggregation for federated learning.
method Multi-group circular strategy, additive secret sharing, and coding techniques.
result Achieves O(NlogN)O(N\log{N}) overhead, compared to O(N2)O(N^2), for up to 50% user dropout.

Semi-supervised node classification in attributed graphs, i.e., graphs with node features, involves learning to classify unlabeled nodes given a partially labeled graph. Label predictions are made by jointly modeling the node and its' neighborhood features. State-of-the-art models for node classification on such attrib…

2018-05-31abs ↗pdf ↗

Improves PU learning for imbalanced data with practical AUL estimation and new training method.

problem Training binary classifiers on datasets with only positive and unlabeled samples.
method Asymptotic unbiased AUL estimation and ProbTagging for imbalanced data.
result ProbTagging increases AUC by up to 10% on industrial and artificial data sets.

Model reduction of Markov processes is a basic problem in modeling state-transition systems. Motivated by the state aggregation approach rooted in control theory, we study the statistical state compression of a discrete-state Markov chain from empirical trajectories. Through the lens of spectral decomposition, we study…

2018-02-08abs ↗pdf ↗

We study cross-country GDP losses due to financial crises in terms of frequency (number of loss events per period) and severity (loss per occurrence). We perform the Loss Distribution Approach (LDA) to estimate a multi-country aggregate GDP loss probability density function and the percentiles associated to extreme eve…

2012-01-04abs ↗pdf ↗

This paper optimizes MDP policies for efficient state aggregation.

problem Optimizing policies in aggregated Markov chains while preserving optimal performance.
method Homomorphic mappings to establish optimal policy equivalence and derive performance bounds.
result Developed HPG and EBHPG methods for efficient aggregation and policy optimization.

In this article we show the relationship between the Pareto distribution and the gamma distribution. This shows that the second one, appropriately extended, explains some anomalies that arise in the practical use of extreme value theory. The results are useful to certain phenomena that are fitted by the Pareto distribu…

2012-11-01abs ↗pdf ↗

Federated edge learning improves with CSIT-free model aggregation using RIS.

problem Lack of CSIT in federated edge learning systems.
method Use RIS to align channel coefficients for model aggregation without CSIT, optimize RIS and receiver jointly.
result Achieves similar learning accuracy as CSIT-based methods without CSIT.

Paper proposes a federated XGBoost for anomaly detection balancing privacy and accuracy.

problem Balancing privacy and accuracy in anomaly detection for unbalanced datasets.
method Proposes a horizontal federated XGBoost algorithm with data aggregation and sparse update processes.
result Demonstrates effectiveness of the proposed scheme compared to state-of-the-arts.

A mechanism to share risks and costs with guarantees against extreme outcomes.

problem Softening extreme individual burdens in risk sharing schemes.
method Formalizes Certified Allocation Problem; uses Conformal Risk Sharing with interpretable sharing policy and split conformal calibration.
result Reduces extreme obligations for high-risk agents while controlling harm to others.

UAIL uses uncertainty estimation to improve control systems in safety-critical tasks.

problem Improving control systems in safety-critical domains like autonomous driving.
method UAIL applies Monte Carlo Dropout to estimate uncertainty in control output and selectively acquire new training data.
result UAIL can reliably predict infractions and outperforms existing algorithms.

Study on existence of ground states for free energy on hyperbolic space.

problem Existence of ground states for a free energy functional on hyperbolic space.
method Derived HLS-type inequalities on Cartan-Hadamard manifolds to prove existence.
result Established conditions for the existence of ground states on hyperbolic space.

We study minority games in efficient regime. By incorporating the utility function and aggregating agents with similar strategies we develop an effective mesoscale notion of state of the game. Using this approach, the game can be represented as a Markov process with substantially reduced number of states with explicitl…

2011-11-29abs ↗pdf ↗

HAXMLNet tackles extreme multi-label text classification with hierarchical attention.

problem Tagging each text with relevant labels from an extreme-scale label set.
method Proposes a hierarchical structure with multi-label attention for efficient and effective XMTC.
result HAXMLNet achieves competitive performance compared to state-of-the-art methods.

Paper develops a method to approximate Markov chains with fewer states.

problem Identifying the state aggregation structure of Markov chains with fewer states.
method Proposes a convex optimization problem with a nonnegative factorization approach.
result The method likely converges to the global solution and outperforms existing methods.

New algorithm for aggregate inference in HMMs with continuous observations.

problem Inference in large populations with indistinguishable individuals and continuous measurements.
method Continuous observation collective forward-backward algorithm extending existing discrete case algorithm.
result Efficacy demonstrated through numerical experiments.

We investigate the properties of a modulus of a foliation on a Riemannian manifold. We give necessary and sufficient conditions for the existence of an extremal function and state some of its properties. We obtain the integral formula which, in a sense, combines the integral over the manifold with integral over the lea…

2012-05-07abs ↗pdf ↗

This paper tackles hidden state inference for HMMs using particle filtering.

problem Inference for hidden states under HMMs is challenging due to unavailable true labels.
method Adaptive conformal inference framework using particle filtering.
result The framework produces prediction sets with specific aggregated coverage levels.