15 Search Results for "Warner, Daniel"

Document
Brief Announcement
DOI: 10.4230/LIPIcs.SAND.2026.25
Brief Announcement: Fault-Tolerant 3D Leader Election in the Amoebot Model

Authors: Daniel Warner and Christian Scheideler

Published in: LIPIcs, Volume 373, 5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026)

Abstract
We study leader election for programmable matter in the amoebot model when particles operate on a lattice graph and may experience crash-recovery failures. We propose a lattice-group view that captures both the classical 2D triangular grid and the 3D face-centered cubic (FCC) grid, including configurations with holes and the full lattice symmetry group. To the best of our knowledge, this is the first leader-election framework for 3D amoebot systems that simultaneously handles holes, the full lattice symmetry group including reflections, and crash-recovery faults. We outline (i) a randomized fault-tolerant leader election algorithm based on Borůvka-style merging of candidate-rooted trees combined with a coordinate-based solitude-verification, and (ii) a deterministic approach for assorted local orientations that simulates a virtual instance for each possible orientation in the symmetry group and breaks residual symmetries via a centroid-guided movement phase. Logarithmic-size coordinates are streamed or stored distributively, preserving constant local memory, while crashes are handled by rerooting so failures partition trees without destroying the global competition structure.
Cite as

Daniel Warner and Christian Scheideler. Brief Announcement: Fault-Tolerant 3D Leader Election in the Amoebot Model. In 5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 373, pp. 25:1-25:6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{warner_et_al:LIPIcs.SAND.2026.25,
  author =	{Warner, Daniel and Scheideler, Christian},
  title =	{{Brief Announcement: Fault-Tolerant 3D Leader Election in the Amoebot Model}},
  booktitle =	{5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026)},
  pages =	{25:1--25:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-427-7},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{373},
  editor =	{Mertzios, George B. and Richa, Andr\'{e}a W.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAND.2026.25},
  URN =		{urn:nbn:de:0030-drops-262593},
  doi =		{10.4230/LIPIcs.SAND.2026.25},
  annote =	{Keywords: Programmable matter, amoebot model, leader election, fault tolerance, 3D lattices, symmetry groups}
}
Document
Brief Announcement
DOI: 10.4230/LIPIcs.SAND.2026.26
Brief Announcement: Leader Election with Noisy Reconfigurable Circuits in the Amoebot Model

Authors: Daniel Warner and Christian Scheideler

Published in: LIPIcs, Volume 373, 5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026)

Abstract
Reconfigurable circuits substantially accelerate coordination tasks in the geometric Amoebot model, but existing circuit-based leader election assumes perfectly reliable circuit beeps and provides only Monte Carlo guarantees. We introduce a natural fault model in which circuit beeps are noisy: whenever at least one amoebot beeps on a circuit in a round, each amoebot hears that beep in the next round independently with probability 1-ε, while direct neighbor-to-neighbor (pin-to-pin) communication remains reliable. In this noisy-circuit model we give a Las Vegas leader election algorithm that terminates in O(√{log n} log n) rounds w.h.p. Moreover, once a leader is elected, we show how to simulate any stationary algorithm that is correct in the noiseless circuit model with only an O(√{log n}) multiplicative overhead in running time. Our techniques combine robust flooding/acknowledgment primitives with a tree-based competition framework (Euler-tour representation, randomized attrition, and deterministic solitude verification).
Cite as

Daniel Warner and Christian Scheideler. Brief Announcement: Leader Election with Noisy Reconfigurable Circuits in the Amoebot Model. In 5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 373, pp. 26:1-26:6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{warner_et_al:LIPIcs.SAND.2026.26,
  author =	{Warner, Daniel and Scheideler, Christian},
  title =	{{Brief Announcement: Leader Election with Noisy Reconfigurable Circuits in the Amoebot Model}},
  booktitle =	{5th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2026)},
  pages =	{26:1--26:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-427-7},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{373},
  editor =	{Mertzios, George B. and Richa, Andr\'{e}a W.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAND.2026.26},
  URN =		{urn:nbn:de:0030-drops-262606},
  doi =		{10.4230/LIPIcs.SAND.2026.26},
  annote =	{Keywords: Programmable matter, amoebot model, leader election, reconfigurable circuits, noisy beeps, Las Vegas algorithms}
}
Document
DOI: 10.4230/LIPIcs.FORC.2026.22
Separating Oblivious and Adaptive Differential Privacy Under Continual Observation

Authors: Mark Bun, Marco Gaboardi, and Connor Wagaman

Published in: LIPIcs, Volume 368, 7th Symposium on Foundations of Responsible Computing (FORC 2026)

Abstract
We resolve an open question of Jain, Raskhodnikova, Sivakumar, and Smith (ICML 2023) by exhibiting a problem separating differential privacy under continual observation in the oblivious and adaptive settings. The continual observation (a.k.a. continual release) model formalizes privacy for streaming algorithms, where data is received over time and output is released at each time step. In the oblivious setting, privacy need only hold for data streams fixed in advance; in the adaptive setting, privacy is required even for streams that can be chosen adaptively based on the streaming algorithm’s output. We describe the first explicit separation between the oblivious and adaptive settings. The problem showing this separation is based on the correlated vector queries problem of Bun, Steinke, and Ullman (SODA 2017). Specifically, we present an (ε,0)-DP algorithm for the oblivious setting that remains accurate for exponentially many time steps in the dimension of the input. On the other hand, we show that every (ε,δ)-DP adaptive algorithm fails to be accurate after releasing output for only a constant number of time steps.
Cite as

Mark Bun, Marco Gaboardi, and Connor Wagaman. Separating Oblivious and Adaptive Differential Privacy Under Continual Observation. In 7th Symposium on Foundations of Responsible Computing (FORC 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 368, pp. 22:1-22:11, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{bun_et_al:LIPIcs.FORC.2026.22,
  author =	{Bun, Mark and Gaboardi, Marco and Wagaman, Connor},
  title =	{{Separating Oblivious and Adaptive Differential Privacy Under Continual Observation}},
  booktitle =	{7th Symposium on Foundations of Responsible Computing (FORC 2026)},
  pages =	{22:1--22:11},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-419-2},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{368},
  editor =	{Lin, Huijia (Rachel)},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FORC.2026.22},
  URN =		{urn:nbn:de:0030-drops-259959},
  doi =		{10.4230/LIPIcs.FORC.2026.22},
  annote =	{Keywords: differential privacy, continual observation, continual release, streaming algorithms, adaptive algorithms}
}
Document
DOI: 10.4230/LIPIcs.ITCS.2026.33
Uniformity Testing Under User-Level Local Privacy

Authors: Clément L. Canonne, Abigail Gentle, and Vikrant Singhal

Published in: LIPIcs, Volume 362, 17th Innovations in Theoretical Computer Science Conference (ITCS 2026)

Abstract
We initiate the study of distribution testing under user-level local differential privacy, where each of n users contributes m samples from the unknown underlying distribution. This setting, albeit very natural, is significantly more challenging than the usual locally private setting, as for the same parameter ε the privacy guarantee must now apply to a full batch of m data points. While some recent work considers distribution learning in this user-level setting, nothing was known for even the most fundamental testing task, uniformity testing (and its generalization, identity testing). We address this gap, by providing (nearly) sample-optimal user-level LDP algorithms for uniformity and identity testing. Motivated by practical considerations, our main focus is on the private-coin, symmetric setting, which does not require users to share a common random seed nor to have been assigned a globally unique identifier.
Cite as

Clément L. Canonne, Abigail Gentle, and Vikrant Singhal. Uniformity Testing Under User-Level Local Privacy. In 17th Innovations in Theoretical Computer Science Conference (ITCS 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 362, pp. 33:1-33:24, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026)

Copy BibTex To Clipboard

@InProceedings{canonne_et_al:LIPIcs.ITCS.2026.33,
  author =	{Canonne, Cl\'{e}ment L. and Gentle, Abigail and Singhal, Vikrant},
  title =	{{Uniformity Testing Under User-Level Local Privacy}},
  booktitle =	{17th Innovations in Theoretical Computer Science Conference (ITCS 2026)},
  pages =	{33:1--33:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-410-9},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{362},
  editor =	{Saraf, Shubhangi},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITCS.2026.33},
  URN =		{urn:nbn:de:0030-drops-253201},
  doi =		{10.4230/LIPIcs.ITCS.2026.33},
  annote =	{Keywords: Differential Privacy, Local Differential Privacy, Uniformity Testing, Identity Testing, Hypothesis Testing, User-Level Differential Privacy, Person-Level Differential Privacy}
}
Document
DOI: 10.4230/LIPIcs.DISC.2025.7
On the Shape Containment Problem Within the Amoebot Model with Reconfigurable Circuits

Authors: Matthias Artmann, Andreas Padalkin, and Christian Scheideler

Published in: LIPIcs, Volume 356, 39th International Symposium on Distributed Computing (DISC 2025)

Abstract
In programmable matter, we consider a large number of tiny, primitive computational entities called particles that run distributed algorithms to control global properties of the particle structure. Shape formation problems, where the particles have to reorganize themselves into a desired shape using basic movement abilities, are particularly interesting. In the related shape containment problem, the particles are given the description of a shape S and have to find maximally scaled representations of S within the initial configuration, without movements. For example, if S is a triangle, they have to identify the largest subsets of particles that already form a triangle. While the shape formation problem is being studied extensively, no attention has been given to the shape containment problem, which may have additional uses besides shape formation, such as detecting structural flaws. In this paper, we consider the shape containment problem within the geometric amoebot model for programmable matter, using its reconfigurable circuit extension to enable the instantaneous transmission of primitive signals on connected subsets of particles. We first prove a lower runtime bound of Ω (√n) synchronous rounds for the general problem, where n is the number of particles. Then, we present simple and efficient primitives for identifying subsets that form the desired shape. Using these primitives, we construct a large class of shapes which we call snowflakes. This class contains, among others, all shapes composed of parallelograms and hexagons, and the class of star convex shapes. Let k be the maximum scale of the considered shape in a given amoebot structure. If the shape is star convex, we solve it within 𝒪 (log² k) rounds. If it is a snowflake but not star convex, we solve it within 𝒪 (√n log n) rounds.
Cite as

Matthias Artmann, Andreas Padalkin, and Christian Scheideler. On the Shape Containment Problem Within the Amoebot Model with Reconfigurable Circuits. In 39th International Symposium on Distributed Computing (DISC 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 356, pp. 7:1-7:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{artmann_et_al:LIPIcs.DISC.2025.7,
  author =	{Artmann, Matthias and Padalkin, Andreas and Scheideler, Christian},
  title =	{{On the Shape Containment Problem Within the Amoebot Model with Reconfigurable Circuits}},
  booktitle =	{39th International Symposium on Distributed Computing (DISC 2025)},
  pages =	{7:1--7:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-402-4},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{356},
  editor =	{Kowalski, Dariusz R.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2025.7},
  URN =		{urn:nbn:de:0030-drops-248240},
  doi =		{10.4230/LIPIcs.DISC.2025.7},
  annote =	{Keywords: Programmable matter, amoebot model, reconfigurable circuits, shape containment}
}
Document
Media Exposition
DOI: 10.4230/LIPIcs.SoCG.2025.81
AmoebotSim 2.0: A Visual Simulation Environment for the Amoebot Model with Reconfigurable Circuits and Joint Movements (Media Exposition)

Authors: Matthias Artmann, Tobias Maurer, Andreas Padalkin, Daniel Warner, and Christian Scheideler

Published in: LIPIcs, Volume 332, 41st International Symposium on Computational Geometry (SoCG 2025)

Abstract
We present AmoebotSim 2.0, a simulation environment for the geometric amoebot model of programmable matter that supports the reconfigurable circuit and joint movement extensions of the model. In the geometric amoebot model, we consider systems of simple computational entities called amoebots in a regular triangular grid environment. We are interested in distributed algorithms that solve coordination and shape formation problems. The reconfigurable circuit and joint movement extensions of the model allow the amoebots to communicate over greater distances and perform more complex movements, overcoming some limitations of the original model. AmoebotSim 2.0 is an open-source simulation environment that supports these extensions and provides a rich graphical interface, flexible simulation features, an extensive API, and comprehensive documentation.
Cite as

Matthias Artmann, Tobias Maurer, Andreas Padalkin, Daniel Warner, and Christian Scheideler. AmoebotSim 2.0: A Visual Simulation Environment for the Amoebot Model with Reconfigurable Circuits and Joint Movements (Media Exposition). In 41st International Symposium on Computational Geometry (SoCG 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 332, pp. 81:1-81:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{artmann_et_al:LIPIcs.SoCG.2025.81,
  author =	{Artmann, Matthias and Maurer, Tobias and Padalkin, Andreas and Warner, Daniel and Scheideler, Christian},
  title =	{{AmoebotSim 2.0: A Visual Simulation Environment for the Amoebot Model with Reconfigurable Circuits and Joint Movements}},
  booktitle =	{41st International Symposium on Computational Geometry (SoCG 2025)},
  pages =	{81:1--81:5},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-370-6},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{332},
  editor =	{Aichholzer, Oswin and Wang, Haitao},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2025.81},
  URN =		{urn:nbn:de:0030-drops-232338},
  doi =		{10.4230/LIPIcs.SoCG.2025.81},
  annote =	{Keywords: Programmable matter, amoebot model, reconfigurable circuits, joint movements, simulator}
}
Artifact
Software
DOI: 10.4230/artifacts.23289
AmoebotSim 2.0

Authors: Matthias Artmann, Tobias Maurer, Andreas Padalkin, Daniel Warner, and Christian Scheideler

Abstract
Cite as

Matthias Artmann, Tobias Maurer, Andreas Padalkin, Daniel Warner, Christian Scheideler. AmoebotSim 2.0 (Software, Source Code). Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@misc{dagstuhl-artifact-23289,
   title = {{AmoebotSim 2.0}}, 
   author = {Artmann, Matthias and Maurer, Tobias and Padalkin, Andreas and Warner, Daniel and Scheideler, Christian},
   note = {Software, version 1.8.4., DFG-SCHE 1592/10-1, swhId: \href{https://archive.softwareheritage.org/swh:1:dir:41a83f85a3e7c6c1d5a2fec79533bef04c7ff770;origin=https://github.com/martmannupb/AmoebotSim-2.0;visit=swh:1:snp:8aeb8f3c490d90e04facd9ff0fd699c06b8a2ab6;anchor=swh:1:rev:5873cfc9aa08099e3ebf3b0ce334b8f28cbda75f}{\texttt{swh:1:dir:41a83f85a3e7c6c1d5a2fec79533bef04c7ff770}} (visited on 2025-06-20)},
   url = {https://github.com/martmannupb/AmoebotSim-2.0},
   doi = {10.4230/artifacts.23289},
}
Document
Brief Announcement
DOI: 10.4230/LIPIcs.SAND.2025.20
Brief Announcement: Efficient Distributed Algorithms for Shape Reduction via Reconfigurable Circuits

Authors: Nada Almalki, Siddharth Gupta, Othon Michail, and Andreas Padalkin

Published in: LIPIcs, Volume 330, 4th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2025)

Abstract
In this paper, we study the problem of efficiently reducing geometric shapes into other such shapes in a distributed setting through size-changing operations. We develop distributed algorithms using the reconfigurable circuit model to enable fast node-to-node communication. Let n denote the number of nodes and k the number of turning points in the initial shape. We show that the system of nodes can reduce itself from any tree to a single node using only shrinking operations in O(k log n) rounds w.h.p. and any tree to its incompressible form in O(log n) rounds given prior knowledge of the incompressible nodes, or O(k log n) without it, w.h.p. We also give an algorithm to transform any tree to a topologically equivalent tree in O(k log n+log² n) rounds w.h.p. using both shrinking and growth operations. On the negative side, we show that one cannot hope for o(log² n)-round transformations for all shapes of Θ(log n) turning points.
Cite as

Nada Almalki, Siddharth Gupta, Othon Michail, and Andreas Padalkin. Brief Announcement: Efficient Distributed Algorithms for Shape Reduction via Reconfigurable Circuits. In 4th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 330, pp. 20:1-20:6, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{almalki_et_al:LIPIcs.SAND.2025.20,
  author =	{Almalki, Nada and Gupta, Siddharth and Michail, Othon and Padalkin, Andreas},
  title =	{{Brief Announcement: Efficient Distributed Algorithms for Shape Reduction via Reconfigurable Circuits}},
  booktitle =	{4th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2025)},
  pages =	{20:1--20:6},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-368-3},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{330},
  editor =	{Meeks, Kitty and Scheideler, Christian},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAND.2025.20},
  URN =		{urn:nbn:de:0030-drops-230730},
  doi =		{10.4230/LIPIcs.SAND.2025.20},
  annote =	{Keywords: growth process, shrinking process, collision avoidance, programmable matter}
}
Document
DOI: 10.4230/LIPIcs.STACS.2025.49
Cycle Counting Under Local Differential Privacy for Degeneracy-Bounded Graphs

Authors: Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya

Published in: LIPIcs, Volume 327, 42nd International Symposium on Theoretical Aspects of Computer Science (STACS 2025)

Abstract
We propose an algorithm for counting the number of cycles under local differential privacy for degeneracy-bounded input graphs. Numerous studies have focused on counting the number of triangles under the privacy notion, demonstrating that the expected 𝓁₂-error of these algorithms is Ω(n^{1.5}), where n is the number of nodes in the graph. When parameterized by the number of cycles of length four (C₄), the best existing triangle counting algorithm has an error of O(n^{1.5} + √C₄) = O(n²). In this paper, we introduce an algorithm with an expected 𝓁₂-error of O(δ^1.5 n^0.5 + δ^0.5 d_max^0.5 n^0.5), where δ is the degeneracy and d_{max} is the maximum degree of the graph. For degeneracy-bounded graphs (δ ∈ Θ(1)) commonly found in practical social networks, our algorithm achieves an expected 𝓁₂-error of O(d_{max}^{0.5} n^{0.5}) = O(n). Our algorithm’s core idea is a precise count of triangles following a preprocessing step that approximately sorts the degree of all nodes. This approach can be extended to approximate the number of cycles of length k, maintaining a similar 𝓁₂-error, namely O(δ^{(k-2)/2} d_max^0.5 n^{(k-2)/2} + δ^{k/2} n^{(k-2)/2}) or O(d_max^0.5 n^{(k-2)/2}) = O(n^{(k-1)/2}) for degeneracy-bounded graphs.
Cite as

Quentin Hillebrand, Vorapong Suppakitpaisarn, and Tetsuo Shibuya. Cycle Counting Under Local Differential Privacy for Degeneracy-Bounded Graphs. In 42nd International Symposium on Theoretical Aspects of Computer Science (STACS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 327, pp. 49:1-49:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{hillebrand_et_al:LIPIcs.STACS.2025.49,
  author =	{Hillebrand, Quentin and Suppakitpaisarn, Vorapong and Shibuya, Tetsuo},
  title =	{{Cycle Counting Under Local Differential Privacy for Degeneracy-Bounded Graphs}},
  booktitle =	{42nd International Symposium on Theoretical Aspects of Computer Science (STACS 2025)},
  pages =	{49:1--49:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-365-2},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{327},
  editor =	{Beyersdorff, Olaf and Pilipczuk, Micha{\l} and Pimentel, Elaine and Thắng, Nguy\~{ê}n Kim},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2025.49},
  URN =		{urn:nbn:de:0030-drops-228748},
  doi =		{10.4230/LIPIcs.STACS.2025.49},
  annote =	{Keywords: Differential privacy, triangle counting, degeneracy, arboricity, graph theory, parameterized accuracy}
}
Document
DOI: 10.4230/LIPIcs.ITCS.2025.53
Differential Privacy on Trust Graphs

Authors: Badih Ghazi, Ravi Kumar, Pasin Manurangsi, and Serena Wang

Published in: LIPIcs, Volume 325, 16th Innovations in Theoretical Computer Science Conference (ITCS 2025)

Abstract
We study differential privacy (DP) in a multi-party setting where each party only trusts a (known) subset of the other parties with its data. Specifically, given a trust graph where vertices correspond to parties and neighbors are mutually trusting, we give a DP algorithm for aggregation with a much better privacy-utility trade-off than in the well-studied local model of DP (where each party trusts no other party). We further study a robust variant where each party trusts all but an unknown subset of at most t of its neighbors (where t is a given parameter), and give an algorithm for this setting. We complement our algorithms with lower bounds, and discuss implications of our work to other tasks in private learning and analytics.
Cite as

Badih Ghazi, Ravi Kumar, Pasin Manurangsi, and Serena Wang. Differential Privacy on Trust Graphs. In 16th Innovations in Theoretical Computer Science Conference (ITCS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 325, pp. 53:1-53:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{ghazi_et_al:LIPIcs.ITCS.2025.53,
  author =	{Ghazi, Badih and Kumar, Ravi and Manurangsi, Pasin and Wang, Serena},
  title =	{{Differential Privacy on Trust Graphs}},
  booktitle =	{16th Innovations in Theoretical Computer Science Conference (ITCS 2025)},
  pages =	{53:1--53:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-361-4},
  ISSN =	{1868-8969},
  year =	{2025},
  volume =	{325},
  editor =	{Meka, Raghu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITCS.2025.53},
  URN =		{urn:nbn:de:0030-drops-226816},
  doi =		{10.4230/LIPIcs.ITCS.2025.53},
  annote =	{Keywords: Differential privacy, trust graphs, minimum dominating set, packing number}
}
Document
Resource Paper
DOI: 10.4230/TGDK.2.2.7
Whelk: An OWL EL+RL Reasoner Enabling New Use Cases

Authors: James P. Balhoff and Christopher J. Mungall

Published in: TGDK, Volume 2, Issue 2 (2024): Special Issue on Resources for Graph Data and Knowledge. Transactions on Graph Data and Knowledge, Volume 2, Issue 2

Abstract
Many tasks in the biosciences rely on reasoning with large OWL terminologies (Tboxes), often combined with even larger databases. In particular, a common task is retrieval queries that utilize relational expressions; for example, “find all genes expressed in the brain or any part of the brain”. Automated reasoning on these ontologies typically relies on scalable reasoners targeting the EL subset of OWL, such as ELK. While the introduction of ELK has been transformative in the incorporation of reasoning into bio-ontology quality control and production pipelines, we have encountered limitations when applying it to use cases involving high throughput query answering or reasoning about datasets describing instances (Aboxes). Whelk is a fast OWL reasoner for combined EL+RL reasoning. As such, it is particularly useful for many biological ontology tasks, particularly those characterized by large Tboxes using the EL subset of OWL, combined with Aboxes targeting the RL subset of OWL. Whelk is implemented in Scala and utilizes immutable functional data structures, which provides advantages when performing incremental or dynamic reasoning tasks. Whelk supports querying complex class expressions at a substantially greater rate than ELK, and can answer queries or perform incremental reasoning tasks in parallel, enabling novel applications of OWL reasoning.
Cite as

James P. Balhoff and Christopher J. Mungall. Whelk: An OWL EL+RL Reasoner Enabling New Use Cases. In Special Issue on Resources for Graph Data and Knowledge. Transactions on Graph Data and Knowledge (TGDK), Volume 2, Issue 2, pp. 7:1-7:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2024)

Copy BibTex To Clipboard

@Article{balhoff_et_al:TGDK.2.2.7,
  author =	{Balhoff, James P. and Mungall, Christopher J.},
  title =	{{Whelk: An OWL EL+RL Reasoner Enabling New Use Cases}},
  journal =	{Transactions on Graph Data and Knowledge},
  pages =	{7:1--7:17},
  ISSN =	{2942-7517},
  year =	{2024},
  volume =	{2},
  number =	{2},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/TGDK.2.2.7},
  URN =		{urn:nbn:de:0030-drops-225918},
  doi =		{10.4230/TGDK.2.2.7},
  annote =	{Keywords: Web Ontology Language, OWL, Semantic Web, ontology, reasoner}
}
Document
Position
DOI: 10.4230/TGDK.1.1.5
Knowledge Graphs for the Life Sciences: Recent Developments, Challenges and Opportunities

Authors: Jiaoyan Chen, Hang Dong, Janna Hastings, Ernesto Jiménez-Ruiz, Vanessa López, Pierre Monnin, Catia Pesquita, Petr Škoda, and Valentina Tamma

Published in: TGDK, Volume 1, Issue 1 (2023): Special Issue on Trends in Graph Data and Knowledge. Transactions on Graph Data and Knowledge, Volume 1, Issue 1

Abstract
The term life sciences refers to the disciplines that study living organisms and life processes, and include chemistry, biology, medicine, and a range of other related disciplines. Research efforts in life sciences are heavily data-driven, as they produce and consume vast amounts of scientific data, much of which is intrinsically relational and graph-structured. The volume of data and the complexity of scientific concepts and relations referred to therein promote the application of advanced knowledge-driven technologies for managing and interpreting data, with the ultimate aim to advance scientific discovery. In this survey and position paper, we discuss recent developments and advances in the use of graph-based technologies in life sciences and set out a vision for how these technologies will impact these fields into the future. We focus on three broad topics: the construction and management of Knowledge Graphs (KGs), the use of KGs and associated technologies in the discovery of new knowledge, and the use of KGs in artificial intelligence applications to support explanations (explainable AI). We select a few exemplary use cases for each topic, discuss the challenges and open research questions within these topics, and conclude with a perspective and outlook that summarizes the overarching challenges and their potential solutions as a guide for future research.
Cite as

Jiaoyan Chen, Hang Dong, Janna Hastings, Ernesto Jiménez-Ruiz, Vanessa López, Pierre Monnin, Catia Pesquita, Petr Škoda, and Valentina Tamma. Knowledge Graphs for the Life Sciences: Recent Developments, Challenges and Opportunities. In Special Issue on Trends in Graph Data and Knowledge. Transactions on Graph Data and Knowledge (TGDK), Volume 1, Issue 1, pp. 5:1-5:33, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

Copy BibTex To Clipboard

@Article{chen_et_al:TGDK.1.1.5,
  author =	{Chen, Jiaoyan and Dong, Hang and Hastings, Janna and Jim\'{e}nez-Ruiz, Ernesto and L\'{o}pez, Vanessa and Monnin, Pierre and Pesquita, Catia and \v{S}koda, Petr and Tamma, Valentina},
  title =	{{Knowledge Graphs for the Life Sciences: Recent Developments, Challenges and Opportunities}},
  journal =	{Transactions on Graph Data and Knowledge},
  pages =	{5:1--5:33},
  year =	{2023},
  volume =	{1},
  number =	{1},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/TGDK.1.1.5},
  URN =		{urn:nbn:de:0030-drops-194791},
  doi =		{10.4230/TGDK.1.1.5},
  annote =	{Keywords: Knowledge graphs, Life science, Knowledge discovery, Explainable AI}
}
Document
DOI: 10.4230/LIPIcs.DNA.28.8
The Structural Power of Reconfigurable Circuits in the Amoebot Model

Authors: Andreas Padalkin, Christian Scheideler, and Daniel Warner

Published in: LIPIcs, Volume 238, 28th International Conference on DNA Computing and Molecular Programming (DNA 28) (2022)

Abstract
The amoebot model [Derakhshandeh et al., SPAA 2014] has been proposed as a model for programmable matter consisting of tiny, robotic elements called amoebots. We consider the reconfigurable circuit extension [Feldmann et al., JCB 2022] of the geometric (variant of the) amoebot model that allows the amoebot structure to interconnect amoebots by so-called circuits. A circuit permits the instantaneous transmission of signals between the connected amoebots. In this paper, we examine the structural power of the reconfigurable circuits. We start with some fundamental problems like the stripe computation problem where, given any connected amoebot structure S, an amoebot u in S, and some axis X, all amoebots belonging to axis X through u have to be identified. Second, we consider the global maximum problem, which identifies an amoebot at the highest possible position with respect to some direction in some given amoebot (sub)structure. A solution to this problem can then be used to solve the skeleton problem, where a (not necessarily simple) cycle of amoebots has to be found in the given amoebot structure which contains all boundary amoebots. A canonical solution to that problem can then be used to come up with a canonical path, which provides a unique characterization of the shape of the given amoebot structure. Constructing canonical paths for different directions will then allow the amoebots to set up a spanning tree and to check symmetry properties of the given amoebot structure. The problems are important for a number of applications like rapid shape transformation, energy dissemination, and structural monitoring. Interestingly, the reconfigurable circuit extension allows polylogarithmic-time solutions to all of these problems.
Cite as

Andreas Padalkin, Christian Scheideler, and Daniel Warner. The Structural Power of Reconfigurable Circuits in the Amoebot Model. In 28th International Conference on DNA Computing and Molecular Programming (DNA 28). Leibniz International Proceedings in Informatics (LIPIcs), Volume 238, pp. 8:1-8:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

Copy BibTex To Clipboard

@InProceedings{padalkin_et_al:LIPIcs.DNA.28.8,
  author =	{Padalkin, Andreas and Scheideler, Christian and Warner, Daniel},
  title =	{{The Structural Power of Reconfigurable Circuits in the Amoebot Model}},
  booktitle =	{28th International Conference on DNA Computing and Molecular Programming (DNA 28)},
  pages =	{8:1--8:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-253-2},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{238},
  editor =	{Ouldridge, Thomas E. and Wickham, Shelley F. J.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DNA.28.8},
  URN =		{urn:nbn:de:0030-drops-167935},
  doi =		{10.4230/LIPIcs.DNA.28.8},
  annote =	{Keywords: progammable matter, amoebot model, reconfigurable circuits, spanning tree, symmetry detection}
}
Document
DOI: 10.4230/LIPIcs.DNA.28.9
Fault-Tolerant Shape Formation in the Amoebot Model

Authors: Irina Kostitsyna, Christian Scheideler, and Daniel Warner

Published in: LIPIcs, Volume 238, 28th International Conference on DNA Computing and Molecular Programming (DNA 28) (2022)

Abstract
The amoebot model is a distributed computing model of programmable matter. It envisions programmable matter as a collection of computational units called amoebots or particles that utilize local interactions to achieve tasks of coordination, movement and conformation. In the geometric amoebot model the particles operate on a hexagonal tessellation of the plane. Within this model, numerous problems such as leader election, shape formation or object coating have been studied. One area that has not received much attention so far, but is highly relevant for a practical implementation of programmable matter, is fault tolerance. The existing literature on that aspect allows particles to crash but assumes that crashed particles do not recover. We proposed a new model [Kostitsyna et al., 2022] in which a crash causes the memory of a particle to be reset and a crashed particle can detect that it has crashed and try to recover using its local information and communication capabilities. We present an algorithm that solves the hexagon shape formation problem in our model if a finite number of crashes occur and a designated leader particle does not fail. At the heart of our solution lies a fault-tolerant implementation of the spanning forest primitive, which, since other algorithms in the amoebot model also make use of it, is also of general interest.
Cite as

Irina Kostitsyna, Christian Scheideler, and Daniel Warner. Fault-Tolerant Shape Formation in the Amoebot Model. In 28th International Conference on DNA Computing and Molecular Programming (DNA 28). Leibniz International Proceedings in Informatics (LIPIcs), Volume 238, pp. 9:1-9:22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

Copy BibTex To Clipboard

@InProceedings{kostitsyna_et_al:LIPIcs.DNA.28.9,
  author =	{Kostitsyna, Irina and Scheideler, Christian and Warner, Daniel},
  title =	{{Fault-Tolerant Shape Formation in the Amoebot Model}},
  booktitle =	{28th International Conference on DNA Computing and Molecular Programming (DNA 28)},
  pages =	{9:1--9:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-253-2},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{238},
  editor =	{Ouldridge, Thomas E. and Wickham, Shelley F. J.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DNA.28.9},
  URN =		{urn:nbn:de:0030-drops-167949},
  doi =		{10.4230/LIPIcs.DNA.28.9},
  annote =	{Keywords: programmable matter, amoebot model, fault tolerance, shape formation}
}
Document
Brief Announcement
DOI: 10.4230/LIPIcs.SAND.2022.23
Brief Announcement: Fault-Tolerant Shape Formation in the Amoebot Model

Authors: Irina Kostitsyna, Christian Scheideler, and Daniel Warner

Published in: LIPIcs, Volume 221, 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022)

Abstract
The amoebot model is a distributed computing model of programmable matter. It envisions programmable matter as a collection of computational units called amoebots or particles that utilize local interactions to achieve tasks of coordination, movement and conformation. In the geometric amoebot model the particles operate on a hexagonal tessellation of the plane. Within this model, numerous problems such as leader election, shape formation or object coating have been studied. One area that has not received much attention so far, but is highly relevant for a practical implementation of programmable matter, is fault tolerance. The existing literature on that aspect allows particles to crash but assumes that crashed particles do not recover. We propose a new model in which a crash causes the memory of a particle to be reset and a crashed particle can detect that it has crashed and try to recover using its local information and communication capabilities. We propose an algorithm that solves the hexagon shape formation problem in our model if a finite number of crashes occur and a designated leader particle does not fail. At the heart of our solution lies a fault-tolerant implementation of the spanning forest primitive, which, since other algorithms in the amoebot model also make use of it, is also of general interest.
Cite as

Irina Kostitsyna, Christian Scheideler, and Daniel Warner. Brief Announcement: Fault-Tolerant Shape Formation in the Amoebot Model. In 1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 221, pp. 23:1-23:3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)

Copy BibTex To Clipboard

@InProceedings{kostitsyna_et_al:LIPIcs.SAND.2022.23,
  author =	{Kostitsyna, Irina and Scheideler, Christian and Warner, Daniel},
  title =	{{Brief Announcement: Fault-Tolerant Shape Formation in the Amoebot Model}},
  booktitle =	{1st Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2022)},
  pages =	{23:1--23:3},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-224-2},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{221},
  editor =	{Aspnes, James and Michail, Othon},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SAND.2022.23},
  URN =		{urn:nbn:de:0030-drops-159656},
  doi =		{10.4230/LIPIcs.SAND.2022.23},
  annote =	{Keywords: Programmable matter, Geometric amoebot model, Fault tolerance, Shape formation}
}
  • Refine by Type
  • 14 Document/PDF
  • 9 Document/HTML
  • 1 Artifact

  • Refine by Publication Year
  • 4 2026
  • 6 2025
  • 1 2024
  • 1 2023
  • 3 2022

  • Refine by Author
  • 8 Scheideler, Christian
  • 7 Warner, Daniel
  • 5 Padalkin, Andreas
  • 3 Artmann, Matthias
  • 2 Kostitsyna, Irina
  • Show More...

  • Refine by Series/Journal
  • 12 LIPIcs
  • 2 TGDK

  • Refine by Classification
  • 5 Theory of computation → Computational geometry
  • 5 Theory of computation → Distributed computing models
  • 3 Theory of computation → Theory of database privacy and security
  • 2 Applied computing → Life and medical sciences
  • 2 Security and privacy → Privacy-preserving protocols
  • Show More...

  • Refine by Keyword
  • 6 amoebot model
  • 5 Programmable matter
  • 4 reconfigurable circuits
  • 2 Differential privacy
  • 2 fault tolerance
  • Show More...

Any Issues?
X

Feedback on the Current Page

CAPTCHA

Thanks for your feedback!

Feedback submitted to Dagstuhl Publishing

Could not send message

Please try again later or send an E-mail
© 2023-2026 Schloss Dagstuhl – LZI GmbH Schloss Dagstuhl – LZI GmbH About DROPS Imprint Privacy Contact