Projects per year
Abstract
In this paper we study a problem of determining when entities are active based on their interactions with each other. We consider a set of entities V and a sequence of time-stamped edges E among the entities. Each edge (u, v, t) ∈ E denotes an interaction between entities u and v at time t. We assume an activity model where each entity is active during at most k time intervals. An interaction (u, v, t) can be explained if at least one of u or v are active at time t. Our goal is to reconstruct the activity intervals for all entities in the network, so as to explain the observed interactions. This problem, the network-untangling problem, can be applied to discover event timelines from complex entity interactions. We provide two formulations of the network-untangling problem: (i) minimizing the total interval length over all entities (sum version), and (ii) minimizing the maximum interval length (max version). We study separately the two problems for k= 1 and k> 1 activity intervals per entity. For the case k= 1 , we show that the sum problem is NP-hard, while the max problem can be solved optimally in linear time. For the sum problem we provide efficient algorithms motivated by realistic assumptions. For the case of k> 1 , we show that both formulations are inapproximable. However, we propose efficient algorithms based on alternative optimization. We complement our study with an evaluation on synthetic and real-world datasets, which demonstrates the validity of our concepts and the good performance of our algorithms.
Original language | English |
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Pages (from-to) | 213-247 |
Number of pages | 35 |
Journal | Data Mining and Knowledge Discovery |
Volume | 35 |
Issue number | 1 |
Early online date | 1 Jan 2020 |
DOIs | |
Publication status | Published - Jan 2021 |
MoE publication type | A1 Journal article-refereed |
Keywords
- 2-sat
- Complex networks
- Linear programming
- Temporal networks
- Timeline reconstruction
- Vertex cover
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Dive into the research topics of 'The network-untangling problem: from interactions to activity timelines'. Together they form a unique fingerprint.Projects
- 3 Finished
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AIDA/Gionis
Gionis, A., Ordozgoiti Rubio, B., Zhang, G. & Muniyappa, S.
01/01/2018 → 30/06/2022
Project: Academy of Finland: Other research funding
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AGRA/Gionis
Gionis, A., Aslay, C., Zhang, G., Ordozgoiti Rubio, B. & Xiao, H.
01/01/2018 → 31/12/2019
Project: Academy of Finland: Other research funding
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NESTOR/Gionis
Xiao, H., Gionis, A., Garimella, K., Vitale, F., Parotsidis, N., Zhang, G., Rozenshtein, P., Galbrun, E., Tatti, N., Scepanovic, S., Matakos, A. & Muniyappa, S.
01/09/2015 → 31/08/2019
Project: Academy of Finland: Other research funding