Search Results for author: Mihai Cucuringu

Found 50 papers, 16 papers with code

Maximum Likelihood Estimation on Stochastic Blockmodels for Directed Graph Clustering

1 code implementation28 Mar 2024 Mihai Cucuringu, Xiaowen Dong, Ning Zhang

This paper studies the directed graph clustering problem through the lens of statistics, where we formulate clustering as estimating underlying communities in the directed stochastic block model (DSBM).

Clustering Graph Clustering +1

Robust Angular Synchronization via Directed Graph Neural Networks

1 code implementation9 Oct 2023 Yixuan He, Gesine Reinert, David Wipf, Mihai Cucuringu

The angular synchronization problem aims to accurately estimate (up to a constant additive phase) a set of unknown angles $\theta_1, \dots, \theta_n\in[0, 2\pi)$ from $m$ noisy measurements of their offsets $\theta_i-\theta_j \;\mbox{mod} \; 2\pi.$ Applications include, for example, sensor network localization, phase retrieval, and distributed clock synchronization.

Retrieval

Dynamic Time Warping for Lead-Lag Relationships in Lagged Multi-Factor Models

no code implementations15 Sep 2023 Yichi Zhang, Mihai Cucuringu, Alexander Y. Shestopaloff, Stefan Zohren

In multivariate time series systems, lead-lag relationships reveal dependencies between time series when they are shifted in time relative to each other.

Dynamic Time Warping Time Series

Graph Neural Networks for Forecasting Multivariate Realized Volatility with Spillover Effects

no code implementations1 Aug 2023 Chao Zhang, Xingyue Pu, Mihai Cucuringu, Xiaowen Dong

We present a novel methodology for modeling and forecasting multivariate realized volatilities using customized graph neural networks to incorporate spillover effects across stocks.

Robust Detection of Lead-Lag Relationships in Lagged Multi-Factor Models

no code implementations11 May 2023 Yichi Zhang, Mihai Cucuringu, Alexander Y. Shestopaloff, Stefan Zohren

In multivariate time series systems, key insights can be obtained by discovering lead-lag relationships inherent in the data, which refer to the dependence between two time series shifted in time relative to one another, and which can be leveraged for the purposes of control, forecasting or clustering.

Clustering Time Series

OFTER: An Online Pipeline for Time Series Forecasting

no code implementations8 Apr 2023 Nikolas Michael, Mihai Cucuringu, Sam Howison

We introduce OFTER, a time series forecasting pipeline tailored for mid-sized multivariate time series.

Dimensionality Reduction Time Series +1

Co-trading networks for modeling dynamic interdependency structures and estimating high-dimensional covariances in US equity markets

no code implementations18 Feb 2023 Yutong Lu, Gesine Reinert, Mihai Cucuringu

The time proximity of trades across stocks reveals interesting topological structures of the equity market in the United States.

DeFi: data-driven characterisation of Uniswap v3 ecosystem & an ideal crypto law for liquidity pools

no code implementations20 Dec 2022 Deborah Miori, Mihai Cucuringu

We conclude our work by testing for relationships between the characteristic mechanisms of each pool, i. e. liquidity provision, consumption, and price variation.

Symphony in the Latent Space: Provably Integrating High-dimensional Techniques with Non-linear Machine Learning Models

no code implementations1 Dec 2022 Qiong Wu, Jian Li, Zhenming Liu, Yanhua Li, Mihai Cucuringu

This paper revisits building machine learning algorithms that involve interactions between entities, such as those between financial assets in an actively managed portfolio, or interactions between users in a social network.

Ensemble Learning Time Series Analysis

SEC Form 13F-HR: Statistical investigation of trading imbalances and profitability analysis

no code implementations19 Sep 2022 Deborah Miori, Mihai Cucuringu

US Institutions with more than $100 million assets under management must disclose part of their long positions into the SEC Form 13F-HR on a quarterly basis.

Management

Returns-Driven Macro Regimes and Characteristic Lead-Lag Behaviour between Asset Classes

no code implementations1 Sep 2022 Deborah Miori, Mihai Cucuringu

We define data-driven macroeconomic regimes by clustering the relative performance in time of indices belonging to different asset classes.

Clustering

MSGNN: A Spectral Graph Neural Network Based on a Novel Magnetic Signed Laplacian

1 code implementation1 Sep 2022 Yixuan He, Michael Permultter, Gesine Reinert, Mihai Cucuringu

In these experiments, we consider tasks related to signed information, tasks related to directional information, and tasks related to both signed and directional information.

Link Prediction Node Clustering +3

Graph similarity learning for change-point detection in dynamic networks

no code implementations29 Mar 2022 Deborah Sulem, Henry Kenlay, Mihai Cucuringu, Xiaowen Dong

The main novelty of our method is to use a siamese graph neural network architecture for learning a data-driven graph similarity function, which allows to effectively compare the current graph and its recent history.

Change Point Detection Fraud Detection +2

DAMNETS: A Deep Autoregressive Model for Generating Markovian Network Time Series

1 code implementation28 Mar 2022 Jase Clarkson, Mihai Cucuringu, Andrew Elliott, Gesine Reinert

Generative models for network time series (also known as dynamic graphs) have tremendous potential in fields such as epidemiology, biology and economics, where complex graph-based dynamics are core objects of study.

Epidemiology Time Series +1

Tail-GAN: Learning to Simulate Tail Risk Scenarios

no code implementations3 Mar 2022 Rama Cont, Mihai Cucuringu, Renyuan Xu, Chao Zhang

The estimation of loss distributions for dynamic portfolios requires the simulation of scenarios representing realistic joint dynamics of their components, with particular importance devoted to the simulation of tail risk scenarios.

Generative Adversarial Network

PyTorch Geometric Signed Directed: A Software Package on Graph Neural Networks for Signed and Directed Graphs

1 code implementation22 Feb 2022 Yixuan He, Xitong Zhang, JunJie Huang, Benedek Rozemberczki, Mihai Cucuringu, Gesine Reinert

While many networks are signed or directed, or both, there is a lack of unified software packages on graph neural networks (GNNs) specially designed for signed and directed networks.

Time Series Time Series Analysis

Volatility forecasting with machine learning and intraday commonality

no code implementations8 Feb 2022 Chao Zhang, Yihuang Zhang, Mihai Cucuringu, Zhongmin Qian

We apply machine learning models to forecast intraday realized volatility (RV), by exploiting commonality in intraday volatility via pooling stock data together, and by incorporating a proxy for the market volatility.

BIG-bench Machine Learning

GNNRank: Learning Global Rankings from Pairwise Comparisons via Directed Graph Neural Networks

1 code implementation1 Feb 2022 Yixuan He, Quan Gan, David Wipf, Gesine Reinert, Junchi Yan, Mihai Cucuringu

In this paper, we introduce neural networks into the ranking recovery problem by proposing the so-called GNNRank, a trainable GNN-based framework with digraph embedding.

Inductive Bias

Option Volume Imbalance as a predictor for equity market returns

no code implementations23 Jan 2022 Nikolas Michael, Mihai Cucuringu, Sam Howison

We investigate the use of the normalized imbalance between option volumes corresponding to positive and negative market views, as a predictor for directional price movements in the spot market.

Local2Global: A distributed approach for scaling representation learning on graphs

1 code implementation12 Jan 2022 Lucas G. S. Jeub, Giovanni Colavizza, Xiaowen Dong, Marya Bazzi, Mihai Cucuringu

Our local2global approach proceeds by first dividing the input graph into overlapping subgraphs (or "patches") and training local representations for each patch independently.

Anomaly Detection Graph Representation Learning

Cross-Impact of Order Flow Imbalance in Equity Markets

no code implementations25 Dec 2021 Rama Cont, Mihai Cucuringu, Chao Zhang

We investigate the impact of order flow imbalance (OFI) on price movements in equity markets in a multi-asset setting.

A Universal End-to-End Approach to Portfolio Optimization via Deep Learning

no code implementations17 Nov 2021 Chao Zhang, Zihao Zhang, Mihai Cucuringu, Stefan Zohren

The designed framework circumvents the traditional forecasting step and avoids the estimation of the covariance matrix, lifting the bottleneck for generalizing to a large amount of instruments.

Portfolio Optimization

SSSNET: Semi-Supervised Signed Network Clustering

1 code implementation13 Oct 2021 Yixuan He, Gesine Reinert, Songchao Wang, Mihai Cucuringu

Node embeddings are a powerful tool in the analysis of networks; yet, their full potential for the important task of node clustering has not been fully exploited.

Cloud Removal Clustering +3

Fragmentation, Price Formation, and Cross-Impact in Bitcoin Markets

no code implementations22 Aug 2021 Jakob Albers, Mihai Cucuringu, Sam Howison, Alexander Y. Shestopaloff

In light of micro-scale inefficiencies induced by the high degree of fragmentation of the Bitcoin trading landscape, we utilize a granular data set comprised of orderbook and trades data from the most liquid Bitcoin markets, in order to understand the price formation process at sub-1 second time scales.

Local2Global: Scaling global representation learning on graphs via local training

2 code implementations26 Jul 2021 Lucas G. S. Jeub, Giovanni Colavizza, Xiaowen Dong, Marya Bazzi, Mihai Cucuringu

Our local2global approach proceeds by first dividing the input graph into overlapping subgraphs (or "patches") and training local representations for each patch independently.

Graph Reconstruction Graph Representation Learning +2

DUKweb: Diachronic word representations from the UK Web Archive corpus

1 code implementation2 Jul 2021 Adam Tsakalidis, Pierpaolo Basile, Marya Bazzi, Mihai Cucuringu, Barbara McGillivray

Lexical semantic change (detecting shifts in the meaning and usage of words) is an important task for social and cultural studies as well as for Natural Language Processing applications.

Change Detection Diachronic Word Embeddings +1

DIGRAC: Digraph Clustering Based on Flow Imbalance

1 code implementation9 Jun 2021 Yixuan He, Gesine Reinert, Mihai Cucuringu

DIGRAC optimizes directed flow imbalance for clustering without requiring label supervision, unlike existing graph neural network methods, and can naturally incorporate node features, unlike existing spectral methods.

Clustering Graph Clustering +1

An extension of the angular synchronization problem to the heterogeneous setting

no code implementations29 Dec 2020 Mihai Cucuringu, Hemant Tyagi

This can be thought of as a natural extension of the angular synchronization problem to the heterogeneous setting of multiple groups of angles, where the measurement graph has an unknown edge-disjoint decomposition $G = G_1 \cup G_2 \ldots \cup G_k$, where the $G_i$'s denote the subgraphs of edges corresponding to each group.

A Linear Transportation $\mathrm{L}^p$ Distance for Pattern Recognition

no code implementations23 Sep 2020 Oliver M. Crook, Mihai Cucuringu, Tim Hurst, Carola-Bibiane Schönlieb, Matthew Thorpe, Konstantinos C. Zygalakis

The transportation $\mathrm{L}^p$ distance, denoted $\mathrm{TL}^p$, has been proposed as a generalisation of Wasserstein $\mathrm{W}^p$ distances motivated by the property that it can be applied directly to colour or multi-channelled images, as well as multivariate time-series without normalisation or mass constraints.

Time Series Time Series Analysis

Spectral Ranking with Covariates

no code implementations8 May 2020 Siu Lun Chau, Mihai Cucuringu, Dino Sejdinovic

We consider spectral approaches to the problem of ranking n players given their incomplete and noisy pairwise comparisons, but revisit this classical problem in light of player covariate information.

Motif-Based Spectral Clustering of Weighted Directed Networks

3 code implementations2 Apr 2020 William George Underwood, Andrew Elliott, Mihai Cucuringu

We conclude that motif-based spectral clustering is a valuable tool for analysis of directed and bipartite weighted networks, which is also scalable and easy to implement.

Clustering

Mining the UK Web Archive for Semantic Change Detection

no code implementations RANLP 2019 Adam Tsakalidis, Marya Bazzi, Mihai Cucuringu, Pierpaolo Basile, Barbara McGillivray

Semantic change detection (i. e., identifying words whose meaning has changed over time) started emerging as a growing area of research over the past decade, with important downstream applications in natural language processing, historical linguistics and computational social science.

Change Detection

Hermitian matrices for clustering directed graphs: insights and applications

no code implementations6 Aug 2019 Mihai Cucuringu, Huan Li, He Sun, Luca Zanetti

Graph clustering is a basic technique in machine learning, and has widespread applications in different domains.

Clustering Graph Clustering +1

Ranking and synchronization from pairwise measurements via SVD

no code implementations6 Jun 2019 Alexandre d'Aspremont, Mihai Cucuringu, Hemant Tyagi

Given a measurement graph $G= (V, E)$ and an unknown signal $r \in \mathbb{R}^n$, we investigate algorithms for recovering $r$ from pairwise measurements of the form $r_i - r_j$; $\{i, j\} \in E$.

SPONGE: A generalized eigenproblem for clustering signed networks

1 code implementation18 Apr 2019 Mihai Cucuringu, Peter Davies, Aldo Glielmo, Hemant Tyagi

We introduce a principled and theoretically sound spectral method for $k$-way clustering in signed graphs, where the affinity measure between nodes takes either positive or negative values.

Constrained Clustering Stochastic Block Model

An MBO scheme for clustering and semi-supervised clustering of signed networks

no code implementations10 Jan 2019 Mihai Cucuringu, Andrea Pizzoferrato, Yves van Gennip

We introduce a principled method for the signed clustering problem, where the goal is to partition a graph whose edge weights take both positive and negative values, such that edges within the same cluster are mostly positive, while edges spanning across clusters are mostly negative.

Clustering

Anomaly Detection in Networks with Application to Financial Transaction Networks

1 code implementation2 Jan 2019 Andrew Elliott, Mihai Cucuringu, Milton Martinez Luaces, Paul Reidy, Gesine Reinert

The first set of synthetic networks was split in a training set of 70 percent of the networks, and a test set of 30 percent of the networks.

Applications Social and Information Networks Physics and Society 05C82

Modeling outcomes of soccer matches

no code implementations4 Jul 2018 Alkeos Tsokos, Santhosh Narayanan, Ioannis Kosmidis, Gianluca Baio, Mihai Cucuringu, Gavin Whitaker, Franz J. Király

The parameters of the Bradley-Terry extensions are estimated by maximizing the log-likelihood, or an appropriately penalized version of it, while the posterior densities of the parameters of the hierarchical Poisson log-linear model are approximated using integrated nested Laplace approximations.

Provably robust estimation of modulo 1 samples of a smooth function with applications to phase unwrapping

no code implementations9 Mar 2018 Mihai Cucuringu, Hemant Tyagi

Given the samples $(x_i, y_i)_{i=1}^{n}$, our goal is to recover smooth, robust estimates of the clean samples $f(x_i) \bmod 1$.

Denoising Riemannian optimization

On denoising modulo 1 samples of a function

no code implementations27 Oct 2017 Mihai Cucuringu, Hemant Tyagi

Given the samples $(x_i, y_i)_{i=1}^{n}$ our goal is to recover smooth, robust estimates of the clean samples $f(x_i) \bmod 1$.

Denoising

Rank Aggregation for Course Sequence Discovery

no code implementations3 Mar 2016 Mihai Cucuringu, Charlie Marshak, Dillon Montag, Puck Rombach

In this work, we adapt the rank aggregation framework for the discovery of optimal course sequences at the university level.

Sync-Rank: Robust Ranking, Constrained Ranking and Rank Aggregation via Eigenvector and Semidefinite Programming Synchronization

no code implementations5 Apr 2015 Mihai Cucuringu

We propose a similar synchronization-based algorithm for the rank-aggregation problem, which integrates in a globally consistent ranking pairwise comparisons given by different rating systems on the same set of items.

Point Localization and Density Estimation from Ordinal kNN graphs using Synchronization

no code implementations3 Apr 2015 Mihai Cucuringu, Joseph Woodworth

We demonstrate the scalability of our approach on large graphs, and show how it compares to the Local Ordinal Embedding (LOE) algorithm, which was recently proposed for recovering the configuration of a cloud of points from pairwise ordinal comparisons between a sparse set of distances.

Density Estimation

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