---
OA_place: publisher
_id: '21651'
abstract:
- lang: eng
  text: "Blockchains enable distributed consensus in permissionless settings, where
    participants\r\nare unknown, dynamically changing, and do not trust each other.
    While Bitcoin,\r\nbased on Proof-of-Work (PoW), was the first protocol in this
    model, significant\r\nresearch has focused on permissionless protocols using alternative
    physical resources,\r\nspecifically Proof-of-Space (PoSpace) and Verifiable Delay
    Functions (VDFs). This\r\nthesis investigates the theoretical limits and design
    space of longest-chain protocols in\r\nthe fully permissionless and dynamically
    available settings using these three resources.\r\nFirst, we address the feasibility
    of blockchains relying solely on storage as a resource.\r\nWe prove a fundamental
    impossibility result: there exists no secure longest-chain\r\nprotocol based exclusively
    on Proof-of-Space in the fully permissionless or dynamically\r\navailable settings.
    Further, we quantify the adversarial capabilities required to execute\r\na double-spend
    attack. Our result formally justifies the necessity of coupling PoSpace\r\nwith
    time-dependent primitives (such as VDFs) or to move to less permissive settings\r\n(quasi-permissionless
    or permissioned) to ensure security.\r\nSecond, we generalize Nakamoto-like heaviest
    chain consensus to protocols utilizing\r\ncombinations of multiple physical resources.
    We analyze chain selection rules governed\r\nby a weight function Γ(S, V,W), which
    assigns weight to blocks based on recorded\r\nSpace (S), VDF speed (V ), and Work
    (W). We provide a complete classification\r\nof secure weight functions, proving
    that a weight function is secure against private\r\ndouble-spend attacks if and
    only if it is homogeneous in the timed resources (V,W)\r\nand sub-homogeneous
    in S. This framework unifies existing protocols like Bitcoin and\r\nChia under
    a single theoretical model and provides a powerful tool for designing new\r\nlongest-chain
    blockchains from a mix of physical resources."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Mirza Ahad
  full_name: Baig, Mirza Ahad
  id: 3EDE6DE4-AA5A-11E9-986D-341CE6697425
  last_name: Baig
citation:
  ama: Baig MA. On secure chain selection rules from physical resources in a permissionless
    setting. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21651">10.15479/AT-ISTA-21651</a>
  apa: Baig, M. A. (2026). <i>On secure chain selection rules from physical resources
    in a permissionless setting</i>. Institute of Science and Technology Austria.
    <a href="https://doi.org/10.15479/AT-ISTA-21651">https://doi.org/10.15479/AT-ISTA-21651</a>
  chicago: Baig, Mirza Ahad. “On Secure Chain Selection Rules from Physical Resources
    in a Permissionless Setting.” Institute of Science and Technology Austria, 2026.
    <a href="https://doi.org/10.15479/AT-ISTA-21651">https://doi.org/10.15479/AT-ISTA-21651</a>.
  ieee: M. A. Baig, “On secure chain selection rules from physical resources in a
    permissionless setting,” Institute of Science and Technology Austria, 2026.
  ista: Baig MA. 2026. On secure chain selection rules from physical resources in
    a permissionless setting. Institute of Science and Technology Austria.
  mla: Baig, Mirza Ahad. <i>On Secure Chain Selection Rules from Physical Resources
    in a Permissionless Setting</i>. Institute of Science and Technology Austria,
    2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21651">10.15479/AT-ISTA-21651</a>.
  short: M.A. Baig, On Secure Chain Selection Rules from Physical Resources in a Permissionless
    Setting, Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-04-02T09:31:34Z
date_published: 2026-03-04T00:00:00Z
date_updated: 2026-04-15T08:45:19Z
day: '04'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: GradSch
- _id: KrPi
doi: 10.15479/AT-ISTA-21651
file:
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  date_updated: 2026-04-13T08:24:13Z
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  file_name: PhD-Thesis-Mirza-Ahad-Baig - Library Submission.zip
  file_size: 139353434
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  checksum: 292a5989262521f7c145a109d1f348cb
  content_type: application/pdf
  creator: mbaig
  date_created: 2026-04-03T17:29:30Z
  date_updated: 2026-04-15T07:37:25Z
  file_id: '21656'
  file_name: 2026_Baig_Mirza_Ahad_Thesis.pdf
  file_size: 1942037
  relation: main_file
file_date_updated: 2026-04-15T07:37:25Z
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc-sa/4.0/
month: '03'
oa: 1
oa_version: Published Version
publication_identifier:
  isbn:
  - 978-3-99078-078-7
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '21134'
    relation: part_of_dissertation
    status: public
  - id: '20587'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Krzysztof Z
  full_name: Pietrzak, Krzysztof Z
  id: 3E04A7AA-F248-11E8-B48F-1D18A9856A87
  last_name: Pietrzak
  orcid: 0000-0002-9139-1654
title: On secure chain selection rules from physical resources in a permissionless
  setting
tmp:
  image: /images/cc_by_nc_sa.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: publisher
_id: '21854'
abstract:
- lang: eng
  text: "As neural-network-based models grow both in size and popularity, interest
    has grown in making the models smaller and more efficient to train. To that end,
    many methods have been proposed to prune models by reducing their number of nonzero
    parameters. Additionally, parameter-efficient fine-tuning, in which a much smaller
    number of parameters than the total contained in the model is updated during training,
    has become very popular, especially in the space of Large Language Models. At
    the same time, the increasingly routine deployment of machine learning in real-world
    applications has spurred a drive to make them more trustworthy - in the sense
    of, among other things, being unbiased, interpretable, and editable. In this thesis,
    we examine the interplay between efficiency and trustworthiness.\r\n\r\nFirst,
    we analyze the effects of model pruning on bias in computer vision models, demonstrating
    that increased sparsity leads to greater bias, largely as a function of increased
    model uncertainty in marginal cases. Based on this observation, we propose several
    bias mitigation techniques. Then, we demonstrate that example-specific model pruning
    can improve model interpretation methods while improving pruning efficiency to
    make example-specific model pruning feasible in real time. Then, we investigate
    the effectiveness of parameter-efficient and data-efficient model personalization
    via fine-tuning, demonstrating that it is highly feasible with very small computational
    and data resources. Finally, we consider efficiency in editing model knowledge
    using a custom synthetic data framework, demonstrating that parameter-efficient,
    low-rank fine-tuning frequently outperforms full-rank fine-tuning, and, additionally,
    that restricting which model blocks are fine-tuned frequently improves results.
    Together, the results in this thesis provide new insights and techniques for combining
    trustworthiness and efficiency during neural network inference and training.\r\n\r\n-----------------“In
    reference to IEEE copyrighted material which is used with permission in this thesis,
    the IEEE does not endorse any of [name of university or educational entity]’s
    products or services. Internal or personal use of this material is permitted.
    If interested in reprinting/republishing IEEE copyrighted material for advertising
    or promotional purposes or for creating new collective works for resale or redistribution,
    please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html
    to learn how to obtain a License from RightsLink. If applicable, University Microfilms
    and/or ProQuest Library, or the Archives of Canada may supply single copies of
    the dissertation.”"
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "The research in this Ph.D. was funded in whole\r\nor in part by
  the Austrian Science Fund (FWF) W1260-N35 (Vienna Graduate School for\r\nComputational
  Optimization). For open access purposes the author has applied a CC BY\r\npublic
  copyright license to any author accepted manuscript version arising from this submission\r\nwherever
  possible. Additionally, I am grateful to Alois Schlögl, Waleed Khalid, and the rest
  of\r\nthe ISTA Scientific Computing team for building and maintaining the infrastructure
  I used\r\nto run experiments. I’m also deeply grateful to the Alistarh group’s administrative
  assistant,\r\nChristine Francois, who always deals with our nonsense with common
  sense and a smile.\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Eugenia B
  full_name: Iofinova, Eugenia B
  id: f9a17499-f6e0-11ea-865d-fdf9a3f77117
  last_name: Iofinova
  orcid: 0000-0002-7778-3221
citation:
  ama: Iofinova EB. On the utility and effects of efficiency in artificial neural
    networks. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21854">10.15479/AT-ISTA-21854</a>
  apa: Iofinova, E. B. (2026). <i>On the utility and effects of efficiency in artificial
    neural networks</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21854">https://doi.org/10.15479/AT-ISTA-21854</a>
  chicago: Iofinova, Eugenia B. “On the Utility and Effects of Efficiency in Artificial
    Neural Networks.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21854">https://doi.org/10.15479/AT-ISTA-21854</a>.
  ieee: E. B. Iofinova, “On the utility and effects of efficiency in artificial neural
    networks,” Institute of Science and Technology Austria, 2026.
  ista: Iofinova EB. 2026. On the utility and effects of efficiency in artificial
    neural networks. Institute of Science and Technology Austria.
  mla: Iofinova, Eugenia B. <i>On the Utility and Effects of Efficiency in Artificial
    Neural Networks</i>. Institute of Science and Technology Austria, 2026, doi:<a
    href="https://doi.org/10.15479/AT-ISTA-21854">10.15479/AT-ISTA-21854</a>.
  short: E.B. Iofinova, On the Utility and Effects of Efficiency in Artificial Neural
    Networks, Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-05-11T08:43:22Z
date_published: 2026-05-11T00:00:00Z
date_updated: 2026-05-19T11:20:28Z
day: '11'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: GradSch
- _id: DaAl
doi: 10.15479/AT-ISTA-21854
file:
- access_level: closed
  checksum: 2e148dad920e3f9b7c32796e0ba2e5f7
  content_type: application/zip
  creator: eiofinov
  date_created: 2026-05-11T08:36:01Z
  date_updated: 2026-05-11T08:36:01Z
  file_id: '21856'
  file_name: EIofinova_thesis_FinalVersion.zip
  file_size: 28479571
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- access_level: open_access
  checksum: b10c2933f386f532b2dbf28b19c5525c
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  creator: eiofinov
  date_created: 2026-05-13T13:10:48Z
  date_updated: 2026-05-13T13:10:48Z
  file_id: '21877'
  file_name: 2026_Iofinova_Eugenia_Thesis.pdf
  file_size: 18137757
  relation: main_file
  success: 1
file_date_updated: 2026-05-13T13:10:48Z
has_accepted_license: '1'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '237'
project:
- _id: 9B9290DE-BA93-11EA-9121-9846C619BF3A
  grant_number: W1260-N35
  name: Vienna Graduate School on Computational Optimization
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '14771'
    relation: part_of_dissertation
    status: public
  - id: '18121'
    relation: part_of_dissertation
    status: public
  - id: '21858'
    relation: part_of_dissertation
    status: public
  - id: '21859'
    relation: part_of_dissertation
    status: public
  - id: '21857'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Dan-Adrian
  full_name: Alistarh, Dan-Adrian
  id: 4A899BFC-F248-11E8-B48F-1D18A9856A87
  last_name: Alistarh
  orcid: 0000-0003-3650-940X
title: On the utility and effects of efficiency in artificial neural networks
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: publisher
_id: '21863'
abstract:
- lang: eng
  text: "Atoms and photons, two things so different but yet so alike. The former,
    the building block of matter, something we learn about in school and imagine it
    as some tiny marbles encircled by other tinier marbles. The latter, an electromagnetic
    wave, a light particle or an excitation of the electromagnetic field. Quantum
    mechanics tells us about the properties of these two entities. And even if it
    sounds, looks and writes counter-intuitive, it has proven right for over a century
    now.\r\n\r\nIn this work, I elaborate on how we tested the laws of quantum mechanics
    and how we used them learn more about the tiny building blocks of nature and the
    fields they use to talk to each other. The atoms we use, are artificial. Superconducting
    qubits, small electrical circuits with quantized energy levels behave like electrons
    that transition between different orbitals in an atom. One of the qubits' advantages,
    is also a big disadvantage. We design the circuits' energy levels and fabricate
    them in a cleanroom. This allows for arbitrary spaced energy levels but in contrast
    to real atoms, prevents two superconducting qubits from being alike. Still, this
    qubit platform is one of the frontrunners for future quantum computing technology
    and testing fundamental physics due to their scalability.\r\n\r\nWe interface
    superconducting qubits, which operate in the GHz regime, with microwave photons.
    We use 3D aluminum cavities as mediators between qubits and photons. The cavities
    allow for non-destructive readout of the qubit state, they shield the qubits from
    noise at the qubit frequency and they give us an easy way to frequency-tune these
    joint systems.\r\n\r\nWe need to operate superconducting qubits and their cavities
    at millikelvin temperatures in dilution refrigerators. At higher temperatures,
    superconductivity suffers and even worse, the environment is filled with thermal
    noise photons. This poses a fundamental limitation on the scalability of superconducting
    qubit devices. Also connecting multiple devices in different fridges does not
    work over room temperature links because the microwave photons used for this purpose
    will be covered in noise and the quantum information they carry, will be unusable.\r\n\r\nInfrared
    photons do not suffer from this noise problem since there are close to zero thermal
    noise photons at their frequencies at room temperature. We cannot simply interface
    superconducting devices with optical photons due their frequency mismatch and
    the destructive effect of optical photons on superconductors. Therefore, we use
    microwave-to-optics transducers that allow to convert microwave photons into optical
    ones and vice-versa. The transducers that we use are macroscopic electro-optic
    transducers using the Pockels effect in a disk-shaped Lithium Niobate whispering
    gallery mode resonator. By using a strong optical pump, photons from the two frequency
    domains experience a beam-splitter interaction and get converted from one to the
    other.\r\n\r\nWe measure the generated optical photons using elaborate optical
    setups, optical heterodyning and single photon detectors to gain knowledge about
    the qubit state or the converted microwave photons. Bridging the microwave and
    the optical world allows us to take advantage of both of their strengths but it
    also requires deep knowledge about both of their working principles.\r\n\r\nIn
    this work, we describe two experiments that our group conducted to showcase the
    opportunities that arise from interfacing superconducting qubits with optical
    photons but also the pitfalls, one may encounter on the way.\r\n\r\nIn the first
    experiment, we managed to all-optically read out a superconducting qubit. We show
    that the assignment fidelity, the probability that a measurement of the qubit
    state matches the prepared state, is close to equal for all-optical, microwave-to-optics
    and conventional microwave readout. We show T1 and T2 measurements for all three
    readout types and give an analysis of the noise caused by the optics. Finally,
    we show that the infrared light does not affect the qubit performance in a negative
    way but that the heating it causes does. This is an important insight that we
    used in the next experiment.\r\n\r\nThe second experiment is the upconversion
    of itinerant single microwave photons to the optical domain. We show that we can
    generate single microwave photons from a qubit-cavity system. We upconvert these
    single photons, measure them with a single photon detector and reconstruct their
    shape. By conducting a single photon Rabi measurement, we show correlations between
    the microwave and the optical domain. And by thorough signal-to-noise measurements
    and noise analysis, we find that we can generate single infrared photons with
    high signal-to-noise ratio 5.1 and low transducer added noise (<0.012 quanta).
    We show that this measurement creates a path towards entanglement of a superconducting
    qubit and an optical photon and what parameters need to be improved to achieve
    it. Additionally, this experiment is a proof of principle for an on-demand infrared
    single photon source. More generally, it allows to link microwave quantum technology
    in general to the optical domain."
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
- _id: LifeSc
- _id: SSU
acknowledgement: "The author of this work was supported by the European Research Council
  under grant no.\r\n101089099 (ERC CoG cQEO) and the European Union’s Horizon 2020
  research and innovation\r\nprogram under grant no. 899354 (FETopen SuperQuLAN).\r\nThis
  work was also supported by the European Research Council under grant nos. 758053\r\n(ERC
  StG QUNNECT), 101248662 (ERC POC CoupledEOT), and the European Innovation\r\nCouncil
  no. 101187231 (PathfinderOpen CIELO). This research was funded in whole or in part\r\nby
  the Austrian Science Fund (FWF) [10.55776/F71]. For open access purposes, the author\r\nhas
  applied a CC BY public copyright license to any author accepted manuscript version
  arising\r\nfrom this submission.\r\niii\r\nMy co-authors in the works mentioned
  later acknowledge generous support from the ISTFELLOW program, the NOMIS-ISTA fellowship,
  the Horizon Europe Program HORIZONCL4-2022-QUANTUM-01-SGA via Project No. 101113946
  OpenSuperQPlus100 and a DOC fellowship of the Austrian Academy of Sciences at IST
  Austria.\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
citation:
  ama: Werner T. Interfacing superconducting qubits with optical photons. 2026. doi:<a
    href="https://doi.org/10.15479/AT-ISTA-21863">10.15479/AT-ISTA-21863</a>
  apa: Werner, T. (2026). <i>Interfacing superconducting qubits with optical photons</i>.
    Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21863">https://doi.org/10.15479/AT-ISTA-21863</a>
  chicago: Werner, Thomas. “Interfacing Superconducting Qubits with Optical Photons.”
    Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21863">https://doi.org/10.15479/AT-ISTA-21863</a>.
  ieee: T. Werner, “Interfacing superconducting qubits with optical photons,” Institute
    of Science and Technology Austria, 2026.
  ista: Werner T. 2026. Interfacing superconducting qubits with optical photons. Institute
    of Science and Technology Austria.
  mla: Werner, Thomas. <i>Interfacing Superconducting Qubits with Optical Photons</i>.
    Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21863">10.15479/AT-ISTA-21863</a>.
  short: T. Werner, Interfacing Superconducting Qubits with Optical Photons, Institute
    of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-05-12T09:04:02Z
date_published: 2026-05-12T00:00:00Z
date_updated: 2026-05-20T13:35:43Z
day: '12'
ddc:
- '530'
- '537'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: JoFi
doi: 10.15479/AT-ISTA-21863
ec_funded: 1
file:
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  date_created: 2026-05-15T15:53:57Z
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file_date_updated: 2026-05-15T15:54:06Z
has_accepted_license: '1'
keyword:
- Superconducting qubits
- Quantum optics
- Single photons and quantum effects
- Nonlinear optics
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '05'
oa: 1
oa_version: Published Version
page: '97'
project:
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 26336814-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '758053'
  name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 5b807754-ab3d-11f0-914f-ff8c34502cc9
  grant_number: '101248662'
  name: Integrated optical coupling for low loss electro-optic interconnects
- _id: 91aaf765-16d5-11f0-9cad-a8e7e44cccb7
  grant_number: '101187231'
  name: 'Cavity-Integrated Electro-Optics: Measuring, Converting and Manipulating
    Microwaves with Light'
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
- _id: bdb7cfc1-d553-11ed-ba76-d2eaab167738
  grant_number: '101080139'
  name: Open Superconducting Quantum Computers (OpenSuperQPlus)
- _id: 9B861AAC-BA93-11EA-9121-9846C619BF3A
  name: NOMIS Fellowship Program
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
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  - id: '19073'
    relation: part_of_dissertation
    status: public
  - id: '21870'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
title: Interfacing superconducting qubits with optical photons
tmp:
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  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
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  short: CC BY (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: publisher
_id: '21918'
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "At different stages of my PhD, my work was supported by several
  grants: the\r\nDOC fellowship of the Austrian Academy of Sciences (26293, awarded
  to me),\r\nthe FWF-SFB grant (PT1032F06504 n. F65, awarded to Jan Maas), and the
  ERC\r\ngrant (PR1032ERC01 n. 716117, awarded to Jan Maas). I also appreciate the
  help\r\nfrom the Scientific Computing unit for their advice on the cluster usage."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Kseniia
  full_name: Khudiakova, Kseniia
  id: 4E6DC800-AE37-11E9-AC72-31CAE5697425
  last_name: Khudiakova
  orcid: 0000-0002-6246-1465
citation:
  ama: Khudiakova K. How epistasis and purifying selection shape genetic diversity.
    2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21918">10.15479/AT-ISTA-21918</a>
  apa: Khudiakova, K. (2026). <i>How epistasis and purifying selection shape genetic
    diversity</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21918">https://doi.org/10.15479/AT-ISTA-21918</a>
  chicago: Khudiakova, Kseniia. “How Epistasis and Purifying Selection Shape Genetic
    Diversity.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21918">https://doi.org/10.15479/AT-ISTA-21918</a>.
  ieee: K. Khudiakova, “How epistasis and purifying selection shape genetic diversity,”
    Institute of Science and Technology Austria, 2026.
  ista: Khudiakova K. 2026. How epistasis and purifying selection shape genetic diversity.
    Institute of Science and Technology Austria.
  mla: Khudiakova, Kseniia. <i>How Epistasis and Purifying Selection Shape Genetic
    Diversity</i>. Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21918">10.15479/AT-ISTA-21918</a>.
  short: K. Khudiakova, How Epistasis and Purifying Selection Shape Genetic Diversity,
    Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-05-27T06:26:08Z
date_published: 2026-06-07T00:00:00Z
date_updated: 2026-06-12T12:43:35Z
day: '07'
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- _id: JaMa
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  call_identifier: H2020
  grant_number: '716117'
  name: Optimal Transport and Stochastic Dynamics
- _id: 34d33d68-11ca-11ed-8bc3-ec13763c0ca8
  grant_number: '26293'
  name: The impact of deleterious mutations on small populations
- _id: fc31cba2-9c52-11eb-aca3-ff467d239cd2
  grant_number: F6504
  name: Taming Complexity in Partial Differential Systems
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  full_name: Barton, Nicholas H
  id: 4880FE40-F248-11E8-B48F-1D18A9856A87
  last_name: Barton
  orcid: 0000-0002-8548-5240
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  id: 4C5696CE-F248-11E8-B48F-1D18A9856A87
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abstract:
- lang: eng
  text: "This thesis investigates algorithmic certification and approximation methods
    for degenerate semidefinite programs (SDPs) and the singular roots of polynomial
    systems. In the first part, we present a hybrid symbolic-numeric algorithm for
    certifying the feasibility of weakly feasible, degenerate SDPs. By reformulating
    linear matrix inequalities (LMIs) into a structured polynomial system via facial
    reduction and incidence varieties, we guarantee the existence of an isolated exact
    solution. This algebraic reduction enables the certification of maximum-rank numerical
    approximations using methods from algebraic geometry.\r\n\r\nIn the second part,
    we address the severe ill-conditioning and loss of quadratic convergence that
    plague standard path-tracking methods near isolated singular roots. To overcome
    this, we propose tracking algorithms that achieve superlinear convergence without
    the computational bloat characteristic of classical deflation techniques. By modeling
    the solution path as a generalized fractional Puiseux series, our approach combines
    an explicitly derived algebraic predictor with a localized hyperplane desingularization
    phase during the corrector step. Furthermore, we introduce a continuous path-limit
    method and an extension of the geometric sequence rule to directly extract exact
    fractional exponents. This bypasses traditional heuristic trial-and-error methods
    and explicitly accommodates sparse series expansions. Numerical experiments confirm
    that our method significantly reduces the cumulative number of matrix inversions
    while achieving high-accuracy root approximations, even for heavily degenerate
    systems exhibiting higher coranks."
acknowledgement: 'Funding: Vienna Graduate School on Computational Optimization (FWF),
  grant DOI: 10.55776/W1260.'
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Jeferson
  full_name: Zapata, Jeferson
  id: 00223538-AF8F-11E9-A4C7-F729E6697425
  last_name: Zapata
citation:
  ama: 'Zapata J. Overcoming degeneracy and singularity : Techniques for semidefinite
    programs and homotopy continuation endgames. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21957">10.15479/AT-ISTA-21957</a>'
  apa: 'Zapata, J. (2026). <i>Overcoming degeneracy and singularity : Techniques for
    semidefinite programs and homotopy continuation endgames</i>. Institute of Science
    and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21957">https://doi.org/10.15479/AT-ISTA-21957</a>'
  chicago: 'Zapata, Jeferson. “Overcoming Degeneracy and Singularity : Techniques
    for Semidefinite Programs and Homotopy Continuation Endgames.” Institute of Science
    and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21957">https://doi.org/10.15479/AT-ISTA-21957</a>.'
  ieee: 'J. Zapata, “Overcoming degeneracy and singularity : Techniques for semidefinite
    programs and homotopy continuation endgames,” Institute of Science and Technology
    Austria, 2026.'
  ista: 'Zapata J. 2026. Overcoming degeneracy and singularity : Techniques for semidefinite
    programs and homotopy continuation endgames. Institute of Science and Technology
    Austria.'
  mla: 'Zapata, Jeferson. <i>Overcoming Degeneracy and Singularity : Techniques for
    Semidefinite Programs and Homotopy Continuation Endgames</i>. Institute of Science
    and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21957">10.15479/AT-ISTA-21957</a>.'
  short: 'J. Zapata, Overcoming Degeneracy and Singularity : Techniques for Semidefinite
    Programs and Homotopy Continuation Endgames, Institute of Science and Technology
    Austria, 2026.'
corr_author: '1'
date_created: 2026-06-08T13:29:52Z
date_published: 2026-06-09T00:00:00Z
date_updated: 2026-06-12T10:37:00Z
day: '09'
ddc:
- '500'
degree_awarded: PhD
department:
- _id: GradSch
- _id: VlKo
doi: 10.15479/AT-ISTA-21957
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  grant_number: W1260-N35
  name: Vienna Graduate School on Computational Optimization
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  issn:
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publisher: Institute of Science and Technology Austria
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status: public
supervisor:
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  full_name: Kolmogorov, Vladimir
  id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87
  last_name: Kolmogorov
title: 'Overcoming degeneracy and singularity : Techniques for semidefinite programs
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  text: "Rapid local adaptation to new environments is critical for species persistence,
    especially in introduced populations. The evolutionary success of these populations
    is fundamentally dictated by the organization of genetic variation—the genomic
    architecture—in the face of severe demographic constraints, such as the founder
    effects and genetic bottlenecks that frequently accompany colonization. A central
    question in evolutionary biology is whether rapid adaptation relies on major-effect
    loci, such as chromosomal inversions, or on many small-effect loci dispersed across
    the genome. Furthermore, the genomic architecture strongly influences the extent
    to which evolutionary outcomes are predictable. Using introduced populations of
    the marine snail, Littorina saxatilis, as a model, this thesis investigates how
    genetic variation and genomic structure drive adaptation following introduction.
    We employed a population genomics approach on experimentally and accidentally
    introduced populations to dissect the specific genomic features that underpin
    divergence in newly colonized environments.\r\n\r\nIn Chapter 2, we tested the
    predictability of local adaptation through an uncommon 30-year transplant experiment
    in nature. By distinguishing allele and chromosomal inversion frequency changes
    from neutral expectations, we found that evolutionary change was highly predictable
    at the macro-scale (phenotypes and chromosomal inversions), but less robust at
    the level of individual collinear loci. This result demonstrates that evolution
    can be predictable when a population possesses sufficient standing genetic variation
    (SGV), with chromosomal inversions acting as key integrated units that facilitate
    a rapid response to selection. Building on this, Chapter 3 applied whole-genome
    sequencing to three accidentally introduced populations (Venice, San Francisco,
    and Redwood City) to investigate their likely source and genomic patterns of divergence.
    We identified genomic regions of remarkable divergence potentially associated
    with local adaptation, and likely fuelled by SGV, while explicitly acknowledging
    the difficulty in disentangling selection signals from the genome-wide effects
    of demographic processes. Furthermore, we found that the divergence patterns relied
    extensively on the collinear genome in these introduced populations, and less
    clearly on the chromosomal inversions. This observation contrasts with local adaptation
    observed in the experimental system that relied on both collinear loci and highly
    selected chromosomal inversions, highlighting how demographic history and genomic
    architecture influence the detectable signature of local adaptation.\r\n\r\nA
    major limitation to conducting large-scale comparative evolutionary studies is
    the lack of data standardization, which prevents the integration of community
    knowledge and high-resolution environmental and genetic data. Chapter 4 addresses
    this by developing a community database for the Littorina system. This platform
    implements standardized protocols for the integration of diverse phenotypic and
    environmental data from multiple Littorina species. Likewise, the platform also
    centralizes the availability of associated genomic data through links to external
    repositories. This database represents a crucial tool to test complex, large-scale
    evolutionary hypotheses.\r\n\r\nCollectively, this thesis strongly reinforces
    the fundamental importance of SGV as the raw material for successful local adaptation,
    a conclusion supported by evidence in both experimental and accidental introductions.
    Furthermore, this work highlights the critical role of the genomic architecture—specifically
    chromosomal inversions—in driving the predictability and effectiveness of adaptive
    responses. Our findings underscore how the interplay between SGV and genomic architecture
    dictates the trajectory and detectability of evolution in colonizing populations,
    while simultaneously providing a necessary tool to advance comparative evolutionary
    genomics in emerging model organisms."
acknowledgement: "I acknowledge the funding agencies 1Norwegian Research Council RCN
  project 315287.\r\n2The FIASCO project \"Illuminating range shifts through evolutionary
  FIASCO: contrasting\r\nFaIling And Successful ColOnizations in replicated wild populations\",
  funded by the\r\nEuropean Union - Next Generation EU (Piano Nazionale di Ripresa
  e Resilienza - MUR\r\ncode: P202229JBC, CUP: C53D23007100001). 3Ecotypic formation
  in Littorina saxatilis\r\nin the Western Atlantic and comparisons across the North
  Atlantic. University of\r\nGothenburg Research Travel Grant, Tjarno Marine Laboratory,
  Sweden. $3023 (2018).\r\n4JIN project (Young Researchers, Spanish Ministry of Science,
  RTI2018-101274-J-I00)"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Diego Fernando
  full_name: Garcia Castillo, Diego Fernando
  id: ae681a14-dc74-11ea-a0a7-c6ef18161701
  last_name: Garcia Castillo
citation:
  ama: Garcia Castillo DF. The genomic architecture of local adaptation in introduced
    populations. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-20991">10.15479/AT-ISTA-20991</a>
  apa: Garcia Castillo, D. F. (2026). <i>The genomic architecture of local adaptation
    in introduced populations</i>. Institute of Science and Technology Austria. <a
    href="https://doi.org/10.15479/AT-ISTA-20991">https://doi.org/10.15479/AT-ISTA-20991</a>
  chicago: Garcia Castillo, Diego Fernando. “The Genomic Architecture of Local Adaptation
    in Introduced Populations.” Institute of Science and Technology Austria, 2026.
    <a href="https://doi.org/10.15479/AT-ISTA-20991">https://doi.org/10.15479/AT-ISTA-20991</a>.
  ieee: D. F. Garcia Castillo, “The genomic architecture of local adaptation in introduced
    populations,” Institute of Science and Technology Austria, 2026.
  ista: Garcia Castillo DF. 2026. The genomic architecture of local adaptation in
    introduced populations. Institute of Science and Technology Austria.
  mla: Garcia Castillo, Diego Fernando. <i>The Genomic Architecture of Local Adaptation
    in Introduced Populations</i>. Institute of Science and Technology Austria, 2026,
    doi:<a href="https://doi.org/10.15479/AT-ISTA-20991">10.15479/AT-ISTA-20991</a>.
  short: D.F. Garcia Castillo, The Genomic Architecture of Local Adaptation in Introduced
    Populations, Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-01-16T09:47:59Z
date_published: 2026-01-16T00:00:00Z
date_updated: 2026-04-16T12:20:37Z
day: '16'
ddc:
- '576'
degree_awarded: PhD
department:
- _id: GradSch
- _id: NiBa
doi: 10.15479/AT-ISTA-20991
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  file_size: 732
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  - 2663-337X
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publisher: Institute of Science and Technology Austria
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  full_name: Barton, Nicholas H
  id: 4880FE40-F248-11E8-B48F-1D18A9856A87
  last_name: Barton
  orcid: 0000-0002-8548-5240
- first_name: Anja M
  full_name: Westram, Anja M
  id: 3C147470-F248-11E8-B48F-1D18A9856A87
  last_name: Westram
  orcid: 0000-0003-1050-4969
title: The genomic architecture of local adaptation in introduced populations
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abstract:
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  text: This thesis examines how geometry and topology intersect in the representation,
    transformation, and analysis of complex shapes. It considers how continuous manifolds
    relate to their discrete analogues, how topological structures evolve in persistence
    vineyards, and how tools from topological data analysis can illuminate problems
    in mathematical physics. Central to this exploration is the question of how structure,
    both geometric and topological, persists or changes under approximation, sampling,
    or deformation. The work develops new approaches to skeletal and grid-based representations
    of surfaces, reveals the full expressive capacity of persistence vineyards, and
    applies topological methods to the longstanding problem of equilibria in electrostatic
    fields. These threads braid together into a broader understanding of how topology
    and geometry inform one another across theory, computation, and application.
acknowledged_ssus:
- _id: M-Shop
- _id: ScienComp
acknowledgement: "The research presented in this thesis was funded by the DFG Collaborative
  Research\r\nCenter TRR 109, ‘Discretization in Geometry and Dynamics’.\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Christopher D
  full_name: Fillmore, Christopher D
  id: 35638A5C-AAC7-11E9-B0BF-5503E6697425
  last_name: Fillmore
citation:
  ama: Fillmore CD. Braiding geometry and topology to study shapes and data. 2026.
    doi:<a href="https://doi.org/10.15479/AT-ISTA-21021">10.15479/AT-ISTA-21021</a>
  apa: Fillmore, C. D. (2026). <i>Braiding geometry and topology to study shapes and
    data</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21021">https://doi.org/10.15479/AT-ISTA-21021</a>
  chicago: Fillmore, Christopher D. “Braiding Geometry and Topology to Study Shapes
    and Data.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21021">https://doi.org/10.15479/AT-ISTA-21021</a>.
  ieee: C. D. Fillmore, “Braiding geometry and topology to study shapes and data,”
    Institute of Science and Technology Austria, 2026.
  ista: Fillmore CD. 2026. Braiding geometry and topology to study shapes and data.
    Institute of Science and Technology Austria.
  mla: Fillmore, Christopher D. <i>Braiding Geometry and Topology to Study Shapes
    and Data</i>. Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21021">10.15479/AT-ISTA-21021</a>.
  short: C.D. Fillmore, Braiding Geometry and Topology to Study Shapes and Data, Institute
    of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-01-20T21:38:40Z
date_published: 2026-01-21T00:00:00Z
date_updated: 2026-04-07T11:42:49Z
day: '21'
ddc:
- '514'
- '516'
degree_awarded: PhD
department:
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- _id: HeEd
- _id: UlWa
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supervisor:
- first_name: Herbert
  full_name: Edelsbrunner, Herbert
  id: 3FB178DA-F248-11E8-B48F-1D18A9856A87
  last_name: Edelsbrunner
  orcid: 0000-0002-9823-6833
- first_name: Uli
  full_name: Wagner, Uli
  id: 36690CA2-F248-11E8-B48F-1D18A9856A87
  last_name: Wagner
  orcid: 0000-0002-1494-0568
title: Braiding geometry and topology to study shapes and data
tmp:
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  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2026'
...
---
OA_place: publisher
_id: '21198'
abstract:
- lang: eng
  text: "In recent years there has been a massive increase in the amount of data generated
    in a\r\ndecentralized manner. Ever more powerful edge devices, such as smartphones,
    have become\r\nubiquitous in most societies on earth. Through text typed, photos
    taken and apps used,\r\nthese devices, which we refer to as clients, generate
    enormous amounts of high quality and\r\ncomplex data. Moreover, the nature of
    these devices means the data they generate is often\r\nsensitive and privacy concerns
    prevent it being gathered and stored in a central location. This\r\npresents a
    challenge to the modern machine learning paradigm that requires central access\r\nto
    large amounts of data. Federated learning (FL) has emerged as one of the answers
    to\r\nthis problem. Rather than bringing the data to the model, FL sends the model
    to the data.\r\nModel training takes place on device, with periodically synchronized
    updates, allowing data to\r\nremain locally stored. While this approach offers
    significant privacy advantages it comes with\r\nits own set of unique challenges.
    These include: data heterogeneity, the notion that different\r\ndevices generate
    data in distinct ways which can negatively impact training dynamics; systems\r\nheterogeneity,
    meaning that different devices may have differing hardware specifications; high\r\ncommunication
    costs, which are induced by the repeated transferring of models over the\r\nnetwork
    and low device computational power, which limits the use of larger models on device.\r\nIn
    this thesis we present a range of methods for federated learning. We focus primarily
    on\r\nthe challenge of data heterogeneity, though the methods presented are designed
    to be well\r\nadapted to the other challenges of a federated setting, such as
    the constraints of limited\r\ncompute and communication overhead. We first present
    a method for explicitly modeling client\r\ndata heterogeneity. The approach formulates
    clients as samples from a certain probability\r\ndistribution and infers the parameters
    of this distribution from the available training clients.\r\nThis learned distribution
    then represents the heterogeneity present among the clients and can\r\nbe sampled
    from in order to create new simulated clients that are similar to the real clients
    we\r\nhave observed so far. Following this we present two methods for directly
    dealing with data\r\nheterogeneity through personalization. Highly heterogeneous
    client data distributions can mean\r\nthat learning a single global model becomes
    suboptimal, and some form of personalization of\r\nmodels to each individual client
    is required. Our approaches are based around hypernetworks,\r\nwhich we use to
    generate personalized model parameters without the need for additional\r\ntraining
    or finetuning. In the first approach we focus on generating full parameterizations
    of\r\nclient models using learned embeddings of client data and labels, with a
    hypernetwork located\r\non the central server. In the second approach we address
    the more challenging scenario where\r\nwe want to generate a personalized model
    for a client without any label information. The\r\nhypernetwork is trained to
    generate a low dimensional representation of a client’s personalized\r\nmodel
    parameters, allowing it to be transferred to and run on the client devices. In
    our final\r\npresented method, we change our focus and rather than aim to directly
    address the challenge\r\nof data heterogeneity, we instead ensure we are unaffected
    by it. This is done in the context\r\nof k-means clustering and we present a method
    for federated clustering with a focus on added\r\nprivacy guarantees."
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "This research was funded in part by the Austrian Science Fund (FWF)\r\n[10.55776/COE12].
  Furthermore, the candidate acknowledges the support from the Scientific\r\nService
  Units (SSU) of ISTA through resources provided by Scientific Computing (SciComp)."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Jonathan A
  full_name: Scott, Jonathan A
  id: e499926b-f6e0-11ea-865d-9c63db0031e8
  last_name: Scott
citation:
  ama: Scott JA. Data heterogeneity and personalization in federated learning. 2026.
    doi:<a href="https://doi.org/10.15479/AT-ISTA-21198">10.15479/AT-ISTA-21198</a>
  apa: Scott, J. A. (2026). <i>Data heterogeneity and personalization in federated
    learning</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21198">https://doi.org/10.15479/AT-ISTA-21198</a>
  chicago: Scott, Jonathan A. “Data Heterogeneity and Personalization in Federated
    Learning.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21198">https://doi.org/10.15479/AT-ISTA-21198</a>.
  ieee: J. A. Scott, “Data heterogeneity and personalization in federated learning,”
    Institute of Science and Technology Austria, 2026.
  ista: Scott JA. 2026. Data heterogeneity and personalization in federated learning.
    Institute of Science and Technology Austria.
  mla: Scott, Jonathan A. <i>Data Heterogeneity and Personalization in Federated Learning</i>.
    Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21198">10.15479/AT-ISTA-21198</a>.
  short: J.A. Scott, Data Heterogeneity and Personalization in Federated Learning,
    Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-02-09T14:59:53Z
date_published: 2026-02-09T00:00:00Z
date_updated: 2026-04-07T11:46:11Z
day: '09'
ddc:
- '005'
degree_awarded: PhD
department:
- _id: GradSch
- _id: ChLa
doi: 10.15479/AT-ISTA-21198
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- iso: eng
month: '02'
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oa_version: Published Version
page: '158'
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
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    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Christoph
  full_name: Lampert, Christoph
  id: 40C20FD2-F248-11E8-B48F-1D18A9856A87
  last_name: Lampert
  orcid: 0000-0001-8622-7887
title: Data heterogeneity and personalization in federated learning
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2026'
...
---
OA_place: repository
_id: '21360'
acknowledged_ssus:
- _id: LifeSc
- _id: Bio
acknowledgement: "I would like to acknowledge the Austrian Academy of Sciences (ÖAW)
  and European\r\nResearch Executive Agency (REA) for funding my research (DOC ÖAW
  Fellowship\r\n26130, Horizon Europe BOLERO Project 101060393). "
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Stefan
  full_name: Riegler, Stefan
  id: FF6018E0-D806-11E9-8E43-0B14E6697425
  last_name: Riegler
  orcid: 0000-0003-3413-1343
citation:
  ama: 'Riegler S. Root system plasticity under nutrient limitation : Investigating
    hormonal and molecular drivers in Arabidopsis thaliana and Coffea  species. 2026.
    doi:<a href="https://doi.org/10.15479/AT-ISTA-21360">10.15479/AT-ISTA-21360</a>'
  apa: 'Riegler, S. (2026). <i>Root system plasticity under nutrient limitation :
    Investigating hormonal and molecular drivers in Arabidopsis thaliana and Coffea 
    species</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21360">https://doi.org/10.15479/AT-ISTA-21360</a>'
  chicago: 'Riegler, Stefan. “Root System Plasticity under Nutrient Limitation : Investigating
    Hormonal and Molecular Drivers in Arabidopsis Thaliana and Coffea  Species.” Institute
    of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21360">https://doi.org/10.15479/AT-ISTA-21360</a>.'
  ieee: 'S. Riegler, “Root system plasticity under nutrient limitation : Investigating
    hormonal and molecular drivers in Arabidopsis thaliana and Coffea  species,” Institute
    of Science and Technology Austria, 2026.'
  ista: 'Riegler S. 2026. Root system plasticity under nutrient limitation : Investigating
    hormonal and molecular drivers in Arabidopsis thaliana and Coffea  species. Institute
    of Science and Technology Austria.'
  mla: 'Riegler, Stefan. <i>Root System Plasticity under Nutrient Limitation : Investigating
    Hormonal and Molecular Drivers in Arabidopsis Thaliana and Coffea  Species</i>.
    Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21360">10.15479/AT-ISTA-21360</a>.'
  short: 'S. Riegler, Root System Plasticity under Nutrient Limitation : Investigating
    Hormonal and Molecular Drivers in Arabidopsis Thaliana and Coffea  Species, Institute
    of Science and Technology Austria, 2026.'
corr_author: '1'
date_created: 2026-02-27T09:08:14Z
date_published: 2026-02-26T00:00:00Z
date_updated: 2026-06-10T09:39:12Z
day: '26'
ddc:
- '570'
- '575'
- '583'
degree_awarded: PhD
department:
- _id: GradSch
- _id: EvBe
doi: 10.15479/AT-ISTA-21360
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  file_size: 31430022
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  date_updated: 2026-03-02T10:59:49Z
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file_date_updated: 2026-03-02T10:59:50Z
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-sa/4.0/
month: '02'
oa_version: Published Version
page: '185'
project:
- _id: 34afa094-11ca-11ed-8bc3-a375845a59fb
  grant_number: '101060393'
  name: Breeding for coffee and cocoa root resilience in low input farming systems
    based on improved rootstocks
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '21363'
    relation: research_data
    status: public
status: public
supervisor:
- first_name: Eva
  full_name: Benková, Eva
  id: 38F4F166-F248-11E8-B48F-1D18A9856A87
  last_name: Benková
  orcid: 0000-0002-8510-9739
title: 'Root system plasticity under nutrient limitation : Investigating hormonal
  and molecular drivers in Arabidopsis thaliana and Coffea  species'
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  short: CC BY-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: repository
_id: '21393'
abstract:
- lang: eng
  text: "This thesis documents a voyage towards truth and beauty via formal verification
    of theorems. To this end, we develop libraries in Lean 4 that present definitions
    and results from diverse areas of MathematiCS (i.e., Mathematics and Computer
    Science). The aim is to create code that is understandable, believable, useful,
    and elegant. The code should stand for itself as much as possible without a need
    for documentation; however, this text redundantly documents our code artifacts
    and provides additional context that isn’t present in the code. This thesis is
    written for readers who know Lean 4 but are not familiar with any of the topics
    presented. We manifest truth and beauty in three formalized areas of MathematiCS.\r\n\r\nWe
    formalize general grammars in Lean 4 and use grammars to show closure of the class
    of type-0 languages under four operations; union, reversal, concatenation, and
    the Kleene star.\r\n\r\nOur second stop is the theory of optimization. Farkas
    established that a system of linear inequalities has a solution if and only if
    we cannot obtain a contradiction by taking a linear combination of the inequalities.
    We state and formally prove several Farkas-like theorems over linearly ordered
    fields in Lean 4. Furthermore, we extend duality theory to the case when some
    coefficients are allowed to take “infinite values”. Additionally, we develop the
    basics of the theory of optimization in terms of the framework called General-Valued
    Constraint Satisfaction Problems, and we prove that, if a Rational-Valued Constraint
    Satisfaction Problem template has symmetric fractional polymorphisms of all arities,
    then its basic LP relaxation is tight.\r\n\r\nOur third stop is matroid theory.
    Seymour’s decomposition theorem is a hallmark result in matroid theory, presenting
    a structural characterization of the class of regular matroids. We aim to formally
    verify Seymour’s theorem in Lean 4. First, we build a library for working with
    totally unimodular matrices. We define binary matroids and their standard representations,
    and we prove that they form a matroid in the sense how Mathlib defines matroids.
    We define regular matroids to be matroids for which there exists a full representation
    rational matrix that is totally unimodular, and we prove that all regular matroids
    are binary. We define 1-sum, 2-sum, and 3 sum of binary matroids as specific ways
    to compose their standard representation matrices. We prove that the 1-sum, the
    2-sum, and the 3-sum of regular matroids are a regular matroid, which concludes
    the composition direction of the Seymour’s theorem. The (more difficult) decomposition
    direction remains unproved.\r\n\r\nIn the pursuit of truth, we focus on identifying
    the trusted code in each project and presenting it faithfully. We emphasize the
    readability and believability of definitions rather than choosing definitions
    that are easier to work with. In search for beauty, we focus on the philosophical
    framework of Roger Scruton, who emphasizes that beauty is not a mere decoration
    but, most importantly, beauty is the means for shaping our place in the world
    and a source of redemption, where it can be viewed as a substitute for religion."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Martin
  full_name: Dvorak, Martin
  id: 40ED02A8-C8B4-11E9-A9C0-453BE6697425
  last_name: Dvorak
  orcid: 0000-0001-5293-214X
citation:
  ama: 'Dvorak M. Pursuit of truth and beauty in Lean 4 : Formally verified theory
    of grammars, optimization, matroids. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21393">10.15479/AT-ISTA-21393</a>'
  apa: 'Dvorak, M. (2026). <i>Pursuit of truth and beauty in Lean 4 : Formally verified
    theory of grammars, optimization, matroids</i>. Institute of Science and Technology
    Austria. <a href="https://doi.org/10.15479/AT-ISTA-21393">https://doi.org/10.15479/AT-ISTA-21393</a>'
  chicago: 'Dvorak, Martin. “Pursuit of Truth and Beauty in Lean 4 : Formally Verified
    Theory of Grammars, Optimization, Matroids.” Institute of Science and Technology
    Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21393">https://doi.org/10.15479/AT-ISTA-21393</a>.'
  ieee: 'M. Dvorak, “Pursuit of truth and beauty in Lean 4 : Formally verified theory
    of grammars, optimization, matroids,” Institute of Science and Technology Austria,
    2026.'
  ista: 'Dvorak M. 2026. Pursuit of truth and beauty in Lean 4 : Formally verified
    theory of grammars, optimization, matroids. Institute of Science and Technology
    Austria.'
  mla: 'Dvorak, Martin. <i>Pursuit of Truth and Beauty in Lean 4 : Formally Verified
    Theory of Grammars, Optimization, Matroids</i>. Institute of Science and Technology
    Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21393">10.15479/AT-ISTA-21393</a>.'
  short: 'M. Dvorak, Pursuit of Truth and Beauty in Lean 4 : Formally Verified Theory
    of Grammars, Optimization, Matroids, Institute of Science and Technology Austria,
    2026.'
corr_author: '1'
date_created: 2026-03-04T09:26:46Z
date_published: 2026-03-04T00:00:00Z
date_updated: 2026-03-27T12:37:00Z
day: '04'
ddc:
- '511'
- '000'
degree_awarded: PhD
department:
- _id: GradSch
- _id: VlKo
doi: 10.15479/AT-ISTA-21393
file:
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has_accepted_license: '1'
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
page: '160'
publication_identifier:
  isbn:
  - 978-3-99078-074-9
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  link:
  - description: Full version of all definitions, statements, and proofs for Chapter
      3.1 (Linear duality)
    relation: software
    url: https://github.com/madvorak/duality/tree/v3.5.0
  - description: Full version of all definitions, statements, and proofs for Chapter
      3.2 (Valued Constraint Satisfaction Problems)
    relation: software
    url: https://github.com/madvorak/vcsp/tree/v8.2.0
  - description: Full version of all definitions, statements, and proofs for Chapter
      4 (Seymour project)
    relation: software
    url: https://github.com/Ivan-Sergeyev/seymour/tree/v1.2.0
  - description: Full version of all definitions, statements, and proofs for Chapter
      5 (Theory of grammars)
    relation: software
    url: https://github.com/madvorak/chomsky/tree/v1.2.0
  - description: Old version (Lean 3) of the project about grammars
    relation: software
    url: https://github.com/madvorak/grammars
  - description: Demonstration of (minimal) requirements for selected algebraic classes
      used in my Ph.D. thesis
    relation: software
    url: https://github.com/madvorak/preliminaries/blob/main/Preliminaries.lean
  record:
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    relation: part_of_dissertation
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  - id: '21398'
    relation: part_of_dissertation
    status: public
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    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Vladimir
  full_name: Kolmogorov, Vladimir
  id: 3D50B0BA-F248-11E8-B48F-1D18A9856A87
  last_name: Kolmogorov
- first_name: Jasmin
  full_name: Blanchette, Jasmin
  last_name: Blanchette
title: 'Pursuit of truth and beauty in Lean 4 : Formally verified theory of grammars,
  optimization, matroids'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
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  short: CC BY (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: repository
_id: '21423'
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "Finally, I gratefully acknowledge funding from the DOC Fellowship
  of the Austrian Academy\r\nof Sciences (OeAW): grant agreement 26360."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Zuzana
  full_name: Dunajova, Zuzana
  id: 4B39F286-F248-11E8-B48F-1D18A9856A87
  last_name: Dunajova
citation:
  ama: Dunajova Z. Geometry-driven self-organization of migrating cells and chiral
    filaments. 2026. doi:<a href="https://doi.org/10.15479/AT-ISTA-21423">10.15479/AT-ISTA-21423</a>
  apa: Dunajova, Z. (2026). <i>Geometry-driven self-organization of migrating cells
    and chiral filaments</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21423">https://doi.org/10.15479/AT-ISTA-21423</a>
  chicago: Dunajova, Zuzana. “Geometry-Driven Self-Organization of Migrating Cells
    and Chiral Filaments.” Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21423">https://doi.org/10.15479/AT-ISTA-21423</a>.
  ieee: Z. Dunajova, “Geometry-driven self-organization of migrating cells and chiral
    filaments,” Institute of Science and Technology Austria, 2026.
  ista: Dunajova Z. 2026. Geometry-driven self-organization of migrating cells and
    chiral filaments. Institute of Science and Technology Austria.
  mla: Dunajova, Zuzana. <i>Geometry-Driven Self-Organization of Migrating Cells and
    Chiral Filaments</i>. Institute of Science and Technology Austria, 2026, doi:<a
    href="https://doi.org/10.15479/AT-ISTA-21423">10.15479/AT-ISTA-21423</a>.
  short: Z. Dunajova, Geometry-Driven Self-Organization of Migrating Cells and Chiral
    Filaments, Institute of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-03-11T08:30:49Z
date_published: 2026-03-11T00:00:00Z
date_updated: 2026-06-10T09:41:11Z
day: '11'
ddc:
- '539'
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: EdHa
doi: 10.15479/AT-ISTA-21423
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  creator: zdunajov
  date_created: 2026-03-12T20:38:52Z
  date_updated: 2026-03-12T20:38:52Z
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  file_name: 2026_Dunajova_Zuzana_Thesis_pdfA.pdf
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acknowledgement: "This project was funded by the European Research Council Advanced
  Grant (ETAP-742985),\r\nEuropean Research Council (ERC; 101142681 CYNIPS), Austrian
  Science Fund (FWF; P\r\n37051-B)."
alternative_title:
- ISTA Thesis
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author:
- first_name: Huihuang
  full_name: Chen, Huihuang
  id: 83c96512-15b2-11ec-abd3-b7eede36184f
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citation:
  ama: Chen H. The cAMP second messenger in auxin signalling. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19478">10.15479/AT-ISTA-19478</a>
  apa: Chen, H. (2025). <i>The cAMP second messenger in auxin signalling</i>. Institute
    of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-19478">https://doi.org/10.15479/AT-ISTA-19478</a>
  chicago: Chen, Huihuang. “The CAMP Second Messenger in Auxin Signalling.” Institute
    of Science and Technology Austria, 2025. <a href="https://doi.org/10.15479/AT-ISTA-19478">https://doi.org/10.15479/AT-ISTA-19478</a>.
  ieee: H. Chen, “The cAMP second messenger in auxin signalling,” Institute of Science
    and Technology Austria, 2025.
  ista: Chen H. 2025. The cAMP second messenger in auxin signalling. Institute of
    Science and Technology Austria.
  mla: Chen, Huihuang. <i>The CAMP Second Messenger in Auxin Signalling</i>. Institute
    of Science and Technology Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-19478">10.15479/AT-ISTA-19478</a>.
  short: H. Chen, The CAMP Second Messenger in Auxin Signalling, Institute of Science
    and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-04-04T07:48:24Z
date_published: 2025-04-04T00:00:00Z
date_updated: 2026-04-28T13:42:45Z
day: '04'
ddc:
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project:
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  call_identifier: H2020
  grant_number: '742985'
  name: Tracing Evolution of Auxin Transport and Polarity in Plants
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  full_name: Friml, Jiří
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  orcid: 0000-0002-8302-7596
title: The cAMP second messenger in auxin signalling
type: dissertation
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abstract:
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  text: "This thesis deals with several different models for complex quantum mechanical
    systems and is structured in three main parts. \r\n\t\r\nIn Part I, we study mean
    field random matrices as models for quantum Hamiltonians. Our focus lies on proving
    concentration estimates for resolvents of random matrices, so-called local laws,
    mostly in the setting of multiple resolvents. These estimates have profound consequences
    for eigenvector overlaps and thermalization problems. More concretely, we obtain,
    e.g., the optimal eigenstate thermalization hypothesis (ETH) uniformly in the
    spectrum for Wigner matrices, an optimal lower bound on non-Hermitian eigenvector
    overlaps, and prethermalization for deformed Wigner matrices.\tIn order to prove
    our novel multi-resolvent local laws, we develop and devise two main methods,
    the static Psi-method and the dynamical Zigzag strategy. \r\n\t\r\nIn Part II,
    we study Bardeen-Cooper-Schrieffer (BCS) theory, the standard mean field microscopic
    theory of superconductivity. We focus on asymptotic formulas for the characteristic
    critical temperature and energy gap of a superconductor and prove universality
    of their ratio in various physical regimes. Additionally, we investigate multi-band
    superconductors and show that inter-band coupling effects can only enhance the
    critical temperature. \r\n\t\r\nIn Part III, we study quantum lattice systems.
    On the one hand, we show a strong version of the local-perturbations-perturb-locally
    (LPPL) principle for the ground state of weakly interacting quantum spin systems
    with a uniform on-site gap. On the other hand, we introduce a notion of a local
    gap and rigorously justify response theory and the Kubo formula under the weakened
    assumption of a local gap. \r\n\t\r\nAdditionally, we discuss two classes of problems
    which do not fit into the three main parts of the thesis. These are deformational
    rigidity of Liouville metrics on the torus and relativistic toy models of particle
    creation via interior-boundary-conditions (IBCs).  "
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Sven Joscha
  full_name: Henheik, Sven Joscha
  id: 31d731d7-d235-11ea-ad11-b50331c8d7fb
  last_name: Henheik
  orcid: 0000-0003-1106-327X
citation:
  ama: 'Henheik SJ. Modeling complex quantum systems : Random matrices, BCS theory,
    and quantum lattice systems. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19540">10.15479/AT-ISTA-19540</a>'
  apa: 'Henheik, S. J. (2025). <i>Modeling complex quantum systems : Random matrices,
    BCS theory, and quantum lattice systems</i>. Institute of Science and Technology
    Austria. <a href="https://doi.org/10.15479/AT-ISTA-19540">https://doi.org/10.15479/AT-ISTA-19540</a>'
  chicago: 'Henheik, Sven Joscha. “Modeling Complex Quantum Systems : Random Matrices,
    BCS Theory, and Quantum Lattice Systems.” Institute of Science and Technology
    Austria, 2025. <a href="https://doi.org/10.15479/AT-ISTA-19540">https://doi.org/10.15479/AT-ISTA-19540</a>.'
  ieee: 'S. J. Henheik, “Modeling complex quantum systems : Random matrices, BCS theory,
    and quantum lattice systems,” Institute of Science and Technology Austria, 2025.'
  ista: 'Henheik SJ. 2025. Modeling complex quantum systems : Random matrices, BCS
    theory, and quantum lattice systems. Institute of Science and Technology Austria.'
  mla: 'Henheik, Sven Joscha. <i>Modeling Complex Quantum Systems : Random Matrices,
    BCS Theory, and Quantum Lattice Systems</i>. Institute of Science and Technology
    Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-19540">10.15479/AT-ISTA-19540</a>.'
  short: 'S.J. Henheik, Modeling Complex Quantum Systems : Random Matrices, BCS Theory,
    and Quantum Lattice Systems, Institute of Science and Technology Austria, 2025.'
corr_author: '1'
date_created: 2025-04-10T21:21:18Z
date_published: 2025-04-10T00:00:00Z
date_updated: 2026-04-07T12:37:12Z
day: '10'
ddc:
- '519'
degree_awarded: PhD
department:
- _id: GradSch
- _id: LaEr
doi: 10.15479/AT-ISTA-19540
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month: '04'
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oa_version: Published Version
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project:
- _id: 62796744-2b32-11ec-9570-940b20777f1d
  call_identifier: H2020
  grant_number: '101020331'
  name: Random matrices beyond Wigner-Dyson-Mehta
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supervisor:
- first_name: László
  full_name: Erdös, László
  id: 4DBD5372-F248-11E8-B48F-1D18A9856A87
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title: 'Modeling complex quantum systems : Random matrices, BCS theory, and quantum
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type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
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acknowledgement: "The work presented in this doctoral thesis was performed at the
  Institute of Science\r\nand Technology (ISTA) and financially supported by a European
  Research Council\r\n(ERC) Consolidator Grant (PR1028ERC02), by SFARI (PR1028SIM02)
  and by the\r\nAustrian Science Fund (FWF) to Gaia Novarino (PE1028W1232). I am very
  thankful\r\nto the Doctoral Program “Molecular Drug Targets” (MolTag) for offering
  me financial\r\nsupport to perform essential experiments during my PhD studies and
  to participate in\r\ninternational conferences and courses."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Lena A
  full_name: Schwarz, Lena A
  id: 29A8453C-F248-11E8-B48F-1D18A9856A87
  last_name: Schwarz
citation:
  ama: Schwarz LA. Mapping developmental dynamics of autism spectrum disorder mouse
    models at single-cell resolution. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19557">10.15479/AT-ISTA-19557</a>
  apa: Schwarz, L. A. (2025). <i>Mapping developmental dynamics of autism spectrum
    disorder mouse models at single-cell resolution</i>. Institute of Science and
    Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-19557">https://doi.org/10.15479/AT-ISTA-19557</a>
  chicago: Schwarz, Lena A. “Mapping Developmental Dynamics of Autism Spectrum Disorder
    Mouse Models at Single-Cell Resolution.” Institute of Science and Technology Austria,
    2025. <a href="https://doi.org/10.15479/AT-ISTA-19557">https://doi.org/10.15479/AT-ISTA-19557</a>.
  ieee: L. A. Schwarz, “Mapping developmental dynamics of autism spectrum disorder
    mouse models at single-cell resolution,” Institute of Science and Technology Austria,
    2025.
  ista: Schwarz LA. 2025. Mapping developmental dynamics of autism spectrum disorder
    mouse models at single-cell resolution. Institute of Science and Technology Austria.
  mla: Schwarz, Lena A. <i>Mapping Developmental Dynamics of Autism Spectrum Disorder
    Mouse Models at Single-Cell Resolution</i>. Institute of Science and Technology
    Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-19557">10.15479/AT-ISTA-19557</a>.
  short: L.A. Schwarz, Mapping Developmental Dynamics of Autism Spectrum Disorder
    Mouse Models at Single-Cell Resolution, Institute of Science and Technology Austria,
    2025.
corr_author: '1'
date_created: 2025-04-14T06:59:06Z
date_published: 2025-04-14T00:00:00Z
date_updated: 2026-04-14T09:07:14Z
day: '14'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: GaNo
doi: 10.15479/AT-ISTA-19557
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  grant_number: '707964'
  name: Critical windows and reversibility of ASD associated with mutations in chromatin
    remodelers
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  grant_number: '101044865'
  name: Toward an understanding of the brain interstitial system and the extracellular
    proteome in health and autism spectrum disorders
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  call_identifier: FWF
  grant_number: W1232
  name: Molecular Drug Targets
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  issn:
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publication_status: published
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status: public
supervisor:
- first_name: Gaia
  full_name: Novarino, Gaia
  id: 3E57A680-F248-11E8-B48F-1D18A9856A87
  last_name: Novarino
  orcid: 0000-0002-7673-7178
title: Mapping developmental dynamics of autism spectrum disorder mouse models at
  single-cell resolution
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abstract:
- lang: eng
  text: "This thesis consists of three chapters, each corresponding to one publication.
    While each of these projects tackles a topic in a different area of research,
    they all share a common thread in the type of topological structure they handle
    - a partition of space into volumes separated by interfaces that meet in non-manifold
    junctions.\r\n\r\nIn Chapter 2, we study clusters of soap bubbles from a simulation
    perspective. In particular, we develop a surface-only algorithm that couples large
    scale motion and shape deformation of soap bubble clusters with the small scale
    evolution of the thin film's thickness, which is responsible for visual phenomena
    like surface vortices, Newton's interference patterns, capillary waves, and deformation-dependent
    rupturing of films in a foam. We model film thickness as a reduced degree of freedom
    in the Navier-Stokes equations and from them derive three sets of equations governing
    normal and tangential motion of the soap film surface, as well as the evolution
    of the thin film thickness. We discretize these equations on a non-manifold triangle
    mesh, extending and adapting operators to handle complex topology. We also present
    an incompressible fluid solver for 2.5D films and an advection algorithm for convecting
    fields across non-manifold surface junctions. Our simulations enhance bubble solvers
    with additional effects caused by convection, rippling, draining, and evaporation
    of the thin film.\r\n\r\nIn Chapter 3, we introduce a multi-material non-manifold
    mesh-based surface tracking algorithm that converts mesh defects, such as overlaps,
    self-intersections, and inversions into topological changes. Our algorithm generalizes
    prior work on manifold surface tracking with topological changes: it preserves
    surface features like mesh-based methods, and it robustly handles topological
    changes like level set methods. Our method also offers improved efficiency and
    robustness over the state of the art. We demonstrate the effectiveness of the
    approach on a range of examples, including complex soap film simulations, such
    as those presented in Chapter 2, but with an order of magnitude more interacting
    bubbles than what we could achieve before, and Boolean unions of non-manifold
    meshes consisting of millions of triangles.\r\n\r\nLastly, in Chapter 4, we utilize
    developments in the theory of random geometric complexes facilitated by observations
    from Discrete Morse theory. We survey the methods and results obtained with this
    new approach, and discuss some of its shortcomings. We use simulations to illustrate
    the results and to form conjectures, getting numerical estimates for combinatorial,
    topological, and geometric properties of weighted and unweighted Delaunay mosaics,
    their dual Voronoi tessellations, and the Alpha and Wrap complexes contained in
    the mosaics."
acknowledged_ssus:
- _id: ScienComp
acknowledgement: The project in Chapter 2 has received funding from the European Research
  Council (ERC) under the European Union's Horizon 2020 research and innovation programme
  under grant agreement No. 638176. The project in Chapter 3 was funded in part by
  the European Union (ERC-2021-COG 101045083 CoDiNA). The project in Chapter 4 has
  received funding from the European Research Council (ERC) under the European Union's
  Horizon 2020 research and innovation programme (grant agreements No 78818 Alpha
  and No 638176). It was also partially supported by the DFG Collaborative Research
  Center TRR 109, 'Discretization in Geometry and Dynamics', through grant no. I02979-N35
  of the Austrian Science Fund (FWF). Thank you for providing funds to support my
  work.
alternative_title:
- ISTA Thesis
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author:
- first_name: Peter
  full_name: Synak, Peter
  id: 331776E2-F248-11E8-B48F-1D18A9856A87
  last_name: Synak
citation:
  ama: Synak P. Methods for fluid simulation, surface tracking, and statistics of
    non-manifold structures. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19630">10.15479/AT-ISTA-19630</a>
  apa: Synak, P. (2025). <i>Methods for fluid simulation, surface tracking, and statistics
    of non-manifold structures</i>. Institute of Science and Technology Austria. <a
    href="https://doi.org/10.15479/AT-ISTA-19630">https://doi.org/10.15479/AT-ISTA-19630</a>
  chicago: Synak, Peter. “Methods for Fluid Simulation, Surface Tracking, and Statistics
    of Non-Manifold Structures.” Institute of Science and Technology Austria, 2025.
    <a href="https://doi.org/10.15479/AT-ISTA-19630">https://doi.org/10.15479/AT-ISTA-19630</a>.
  ieee: P. Synak, “Methods for fluid simulation, surface tracking, and statistics
    of non-manifold structures,” Institute of Science and Technology Austria, 2025.
  ista: Synak P. 2025. Methods for fluid simulation, surface tracking, and statistics
    of non-manifold structures. Institute of Science and Technology Austria.
  mla: Synak, Peter. <i>Methods for Fluid Simulation, Surface Tracking, and Statistics
    of Non-Manifold Structures</i>. Institute of Science and Technology Austria, 2025,
    doi:<a href="https://doi.org/10.15479/AT-ISTA-19630">10.15479/AT-ISTA-19630</a>.
  short: P. Synak, Methods for Fluid Simulation, Surface Tracking, and Statistics
    of Non-Manifold Structures, Institute of Science and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-04-29T09:39:34Z
date_published: 2025-04-29T00:00:00Z
date_updated: 2026-04-16T08:29:34Z
day: '29'
ddc:
- '519'
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degree_awarded: PhD
department:
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- _id: GradSch
doi: 10.15479/AT-ISTA-19630
ec_funded: 1
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oa: 1
oa_version: Published Version
page: '106'
project:
- _id: 2533E772-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '638176'
  name: 'Big Splash: Efficient Simulation of Natural Phenomena at Extremely Large
    Scales'
- _id: 34bc2376-11ca-11ed-8bc3-9a3b3961a088
  grant_number: '101045083'
  name: Computational Discovery of Numerical Algorithms for Animation and Simulation
    of Natural Phenomena
- _id: 266A2E9E-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '788183'
  name: Alpha Shape Theory Extended
- _id: 2533E772-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '638176'
  name: 'Big Splash: Efficient Simulation of Natural Phenomena at Extremely Large
    Scales'
- _id: 2561EBF4-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: I02979-N35
  name: Persistence and stability of geometric complexes
publication_identifier:
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publisher: Institute of Science and Technology Austria
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supervisor:
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  full_name: Wojtan, Christopher J
  id: 3C61F1D2-F248-11E8-B48F-1D18A9856A87
  last_name: Wojtan
  orcid: 0000-0001-6646-5546
title: Methods for fluid simulation, surface tracking, and statistics of non-manifold
  structures
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
---
OA_place: publisher
_id: '19684'
abstract:
- lang: eng
  text: "The overarching goal of this thesis is to break down the complexity of turbulent
    flows in terms of enumerable, coherent structures and patterns. In a five-paper
    series, we adopt a variety of perspectives and techniques to relate the properties
    of systems of increasing complexity to their underlying coherent structures. \r\n\r\nInitially,
    we take a dynamical systems point of view, seeing turbulent flow as a chaotic
    trajectory bouncing between exact unstable solutions of the underlying equations
    of motion. Using persistent homology, the main tool of topological data analysis
    capturing the persistence across scales of topological features in a point cloud,
    we introduce a method that quantifies visits of turbulent trajectories to unstable
    time-periodic solutions, also called periodic orbits. We demonstrate this method
    first in the Rössler and Kuramoto–Sivashinsky systems. Using this method in 3D
    Kolmogorov flow, we extract a Markov chain from turbulent data, where each node
    corresponds to the neighbourhood of a periodic orbit. The invariant distribution
    of this Markov chain reproduces expectation values on turbulent data when it is
    used to weight averages on the respective periodic orbits.\r\n\r\nIn more realistic,
    wall-bounded settings, such as plane-Couette flow (pcf) driven by the relative
    motion of the walls, or plane-Poiseuille flow (ppf) driven by a pressure gradient,
    finding exact solutions is difficult. We use dynamic mode decomposition (DMD),
    a dimensionality reduction method for sequential data, to identify and approximate
    low-dimensional dynamics without knowing any exact solutions. Most spatially-extended
    systems are equivariant under translations, and in such cases spatial drifts dominate
    DMD, hindering its use in the search for and modelling of low-dimensional dynamics.
    We augment DMD with a symmetry reduction method trained on turbulent data to stop
    it from seeing translations as a feature, improving its ability to extract dynamical
    information in translation-equivariant systems. We find segments of turbulent
    trajectories that linearize well with their symmetry-reduced DMD spectra, akin
    to dynamics near exact solutions. Searching for harmonics in the spectra gives
    leads for periodic orbits with spatial drifts, one of which converges to a new
    solution.\r\n\r\nIn larger domains, turbulence can localize and coexist with surrounding
    laminar flow. Our preceding approaches are global, taking all of a domain into
    account at once, and cannot readily treat each localized patch individually. Working
    first in a minimal oblique domain that can host a single 1D-localized turbulent
    patch, we find that turbulence in ppf is connected to a stable periodic orbit
    at a flow velocity much lower than when turbulence is first onset. We show that,
    well in advance of sustained turbulence, chaos sets in explosively, and for long
    time horizons, time series are consistent with that of a random process.\r\n\r\nFinally,
    in much larger domains, we study and compare 2D-localized turbulence that appears
    as large-scale inclined structures, called stripes, in ppf and pcf. While appearing
    similar, we find that stripes in these two settings differ significantly in terms
    of how they sustain themselves, and in higher velocities, how they proliferate."
acknowledged_ssus:
- _id: ScienComp
acknowledgement: "The work in this thesis was supported by a grant from the Simons
  Foundation (662960, BH).\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Gökhan
  full_name: Yalniz, Gökhan
  id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425
  last_name: Yalniz
  orcid: 0000-0002-8490-9312
citation:
  ama: 'Yalniz G. Transition to turbulence : Data-, solution-, and pattern-driven
    approaches. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19684">10.15479/AT-ISTA-19684</a>'
  apa: 'Yalniz, G. (2025). <i>Transition to turbulence : Data-, solution-, and pattern-driven
    approaches</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-19684">https://doi.org/10.15479/AT-ISTA-19684</a>'
  chicago: 'Yalniz, Gökhan. “Transition to Turbulence : Data-, Solution-, and Pattern-Driven
    Approaches.” Institute of Science and Technology Austria, 2025. <a href="https://doi.org/10.15479/AT-ISTA-19684">https://doi.org/10.15479/AT-ISTA-19684</a>.'
  ieee: 'G. Yalniz, “Transition to turbulence : Data-, solution-, and pattern-driven
    approaches,” Institute of Science and Technology Austria, 2025.'
  ista: 'Yalniz G. 2025. Transition to turbulence : Data-, solution-, and pattern-driven
    approaches. Institute of Science and Technology Austria.'
  mla: 'Yalniz, Gökhan. <i>Transition to Turbulence : Data-, Solution-, and Pattern-Driven
    Approaches</i>. Institute of Science and Technology Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-19684">10.15479/AT-ISTA-19684</a>.'
  short: 'G. Yalniz, Transition to Turbulence : Data-, Solution-, and Pattern-Driven
    Approaches, Institute of Science and Technology Austria, 2025.'
corr_author: '1'
date_created: 2025-05-12T15:12:28Z
date_published: 2025-05-13T00:00:00Z
date_updated: 2026-06-18T19:23:35Z
day: '13'
ddc:
- '514'
- '519'
- '532'
- '004'
degree_awarded: PhD
department:
- _id: GradSch
- _id: BjHo
doi: 10.15479/AT-ISTA-19684
file:
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  creator: gyalniz
  date_created: 2025-05-12T15:15:59Z
  date_updated: 2025-05-12T15:43:28Z
  description: '3D visualizations of the turbulent flow (left) and the periodic orbits
    (middle) that are being shadowed along with the local state space projections
    (right) onto the principal components of the respective periodic orbit. Shown
    here are the isosurfaces of velocity (red/blue: ±95% of the instantaneous maximum)
    and vorticity (purple/green: ±65% of the instantaneous maximum) in the x-direction.
    Markers along the projections are in sync with the 3D visualizations. The movie
    corresponds to the initial time interval (up to t = 100) of figure 2.2 (a,b);
    periodic orbits and the state space projections are shown only through the shadowing
    events indicated in figure 2.2 (b).'
  file_id: '19686'
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  creator: gyalniz
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  date_updated: 2025-05-12T15:43:28Z
  description: 'Turbulent flow (left) in HKW domain and its symmetry reduction (right).
    Shown here are the isosurfaces of streamwise velocity (red/blue: u = 0.5 max/min
    u) and streamwise vorticity (green/purple: ω_x = 0.5 max/min ω_x).'
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  creator: gyalniz
  date_created: 2025-05-12T15:16:21Z
  date_updated: 2025-05-12T15:43:28Z
  description: 'Turbulent flow (left) in P2K domain and its symmetry reduction (right).
    Shown here are the isosurfaces of streamwise velocity (red/blue: u = 0.5 max/min
    u) and streamwise vorticity (green/purple: ω_x = 0.5 max/min ω_x).'
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  creator: gyalniz
  date_created: 2025-05-12T15:16:36Z
  date_updated: 2025-05-12T15:43:28Z
  description: 'Relative periodic orbit RPO_79.4 (left) of the plane-Couette flow
    (HKW domain) and its symmetry reduction (right). Shown here are the isosurfaces
    of streamwise velocity (red/blue: u = 0.5 max/min u) and streamwise vorticity
    (green/purple: ω_x = 0.5 max/min ω_x).'
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  creator: gyalniz
  date_created: 2025-05-12T15:16:50Z
  date_updated: 2025-05-12T15:43:28Z
  description: 'Symmetry-reduced flow (left), its SRDMD approximation (middle), and
    state space projection (right) showing the spiral-out episode in P2K domain (figure
    3.6 (b) and figure 3.8 (b)). Shown here are the isosurfaces of streamwise velocity
    (red/blue: u = 0.5 max/min u) and streamwise vorticity (green/purple: ω_x = 0.5
    max/min ω_x).'
  file_id: '19690'
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  creator: gyalniz
  date_created: 2025-05-12T15:17:11Z
  date_updated: 2025-05-12T15:43:28Z
  description: Movie demonstrating the quasi-steady Reynolds number descent from turbulence
    to a periodic orbit.
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  content_type: video/mp4
  creator: gyalniz
  date_created: 2025-05-12T15:17:43Z
  date_updated: 2025-05-12T15:43:28Z
  description: Streamwise velocity fluctuations (from laminar) of plane-Couette flow
    (Re^C =335) at the y = 0 wall-normal plane in coordinates stationary with respect
    to the bulk velocity. Here, x is the streamwise direction (the wall at y = 1 moves
    to the right) and z is the spanwise direction. Time is in advectime time units.
    Shown is the full (L_x = L_z = 400) domain.
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  content_type: video/mp4
  creator: gyalniz
  date_created: 2025-05-12T15:17:49Z
  date_updated: 2025-05-12T15:43:28Z
  description: Streamwise velocity fluctuations (from laminar) of plane-Poiseuille
    flow (Re^P =660) at the y = 0.5 wall-normal plane in coordinates stationary with
    respect to the bulk velocity. Here, x is the streamwise direction (the mean negative
    pressure gradient is to the right) and z is the spanwise direction. Time is in
    advectime time units. Shown is the full (L_x = L_z = 400) domain.
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  content_type: video/mp4
  creator: gyalniz
  date_created: 2025-05-12T15:17:58Z
  date_updated: 2025-05-12T15:43:28Z
  description: Streamwise velocity fluctuations (from laminar) of plane-Poiseuille
    flow (Re^P=660) at the y = 0.5 wall-normal plane in coordinates stationary with
    respect to the average velocity of the downstream tip of the stripe. Here, x is
    the streamwise direction (the mean negative pressure gradient is to the right)
    and z is the spanwise direction. Time is in advectime time units. Shown is a zoom-in
    of the full (L_x = L_z) domain.
  file_id: '19694'
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has_accepted_license: '1'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '155'
project:
- _id: 238598C6-32DE-11EA-91FC-C7463DDC885E
  grant_number: '662960'
  name: Revisiting the Turbulence Problem Using Statistical Mechanics
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '9558'
    relation: part_of_dissertation
    status: public
  - id: '12105'
    relation: part_of_dissertation
    status: public
  - id: '13274'
    relation: part_of_dissertation
    status: public
  - id: '14466'
    relation: part_of_dissertation
    status: public
  - id: '7563'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Björn
  full_name: Hof, Björn
  id: 3A374330-F248-11E8-B48F-1D18A9856A87
  last_name: Hof
  orcid: 0000-0003-2057-2754
title: 'Transition to turbulence : Data-, solution-, and pattern-driven approaches'
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
---
OA_place: publisher
_id: '19759'
abstract:
- lang: eng
  text: "Despite generating remarkable results in various computer vision tasks, deep
    learning comes\r\nwith some surprising shortcomings. For example, tiny perturbations,
    often imperceptible to\r\nthe human eye, can completely change the predictions
    of image classifiers. Despite a decade\r\nof research, the field has made limited
    progress in developing image classifiers that are both\r\naccurate and robust.
    This thesis aims to address this gap.\r\nAs our first contribution, we aim to
    simplify the process of training certifiably robust image\r\nclassifiers. We do
    this by designing a convolutional layer that does not require executing an\r\niterative
    procedure in every forward pass, but relies on an explicit bound instead. We also\r\npropose
    a loss function that allows optimizing for a particular margin more precisely.\r\nNext,
    we provide an overview and comparison of various methods that create robust image\r\nclassifiers
    by constraining the Lipschitz constant. This is important since generally longer\r\ntraining
    times and more parameters improve the performance of robust classifiers, making
    it\r\nchallenging to determine the most practical and effective methods from existing
    literature.\r\nIn 1-Lipschitz classification, the performance of current methods
    is still much worse than what\r\nwe expect on the simple tasks we consider. Therefore,
    we next investigate potential causes of\r\nthis shortcoming. We first consider
    the role of the activation function. We prove a theoretical\r\nshortcoming of
    the commonly used activation function, and provide an alternative without it.\r\nHowever
    this theoretical improvement does barely translate to the empirical performance
    of\r\nrobust classifiers, suggesting a different bottleneck.\r\nTherefore, in
    the final chapter, we study how the performance depends on the amount of\r\ntraining
    data. We prove that in the worst case, we might require far more data to train
    a\r\nrobust classifier compared to a normal one. We furthermore find that the
    amount of training\r\ndata is a key determinant of the performance current methods
    achieve on popular datasets.\r\nAdditionally, we show that linear subspaces exist
    with tiny data variance, and yet we can\r\nstill train very accurate classifiers
    after projecting into those subspaces. This shows that on\r\nthe datasets considered,
    enforcing robustness in classification makes the task strictly more\r\nchallenging.\r\n\r\n-----------------“In
    reference to IEEE copyrighted material which is used with permission in this thesis,
    the IEEE does not endorse any of [name of university or educational entity]’s
    products or services. Internal or personal use of this material is permitted.
    If interested in reprinting/republishing IEEE copyrighted material for advertising
    or promotional purposes or for creating new collective works for resale or redistribution,
    please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html
    to learn how to obtain a License from RightsLink. If applicable, University Microfilms
    and/or ProQuest Library, or the Archives of Canada may supply single copies of
    the dissertation.”\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Bernd
  full_name: Prach, Bernd
  id: 2D561D42-C427-11E9-89B4-9C1AE6697425
  last_name: Prach
citation:
  ama: Prach B. Robust image classification with 1-Lipschitz networks. 2025. doi:<a
    href="https://doi.org/10.15479/10.15479/at-ista-19759">10.15479/10.15479/at-ista-19759</a>
  apa: Prach, B. (2025). <i>Robust image classification with 1-Lipschitz networks</i>.
    Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/10.15479/at-ista-19759">https://doi.org/10.15479/10.15479/at-ista-19759</a>
  chicago: Prach, Bernd. “Robust Image Classification with 1-Lipschitz Networks.”
    Institute of Science and Technology Austria, 2025. <a href="https://doi.org/10.15479/10.15479/at-ista-19759">https://doi.org/10.15479/10.15479/at-ista-19759</a>.
  ieee: B. Prach, “Robust image classification with 1-Lipschitz networks,” Institute
    of Science and Technology Austria, 2025.
  ista: Prach B. 2025. Robust image classification with 1-Lipschitz networks. Institute
    of Science and Technology Austria.
  mla: Prach, Bernd. <i>Robust Image Classification with 1-Lipschitz Networks</i>.
    Institute of Science and Technology Austria, 2025, doi:<a href="https://doi.org/10.15479/10.15479/at-ista-19759">10.15479/10.15479/at-ista-19759</a>.
  short: B. Prach, Robust Image Classification with 1-Lipschitz Networks, Institute
    of Science and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-05-28T16:20:48Z
date_published: 2025-05-30T00:00:00Z
date_updated: 2026-04-07T11:49:52Z
day: '30'
ddc:
- '000'
degree_awarded: PhD
department:
- _id: GradSch
- _id: ChLa
doi: 10.15479/10.15479/at-ista-19759
file:
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has_accepted_license: '1'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '84'
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
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  - id: '17426'
    relation: part_of_dissertation
    status: public
  - id: '11839'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Christoph
  full_name: Lampert, Christoph
  id: 40C20FD2-F248-11E8-B48F-1D18A9856A87
  last_name: Lampert
  orcid: 0000-0001-8622-7887
title: Robust image classification with 1-Lipschitz networks
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
---
OA_place: publisher
_id: '19903'
abstract:
- lang: eng
  text: "Cooperation, that is, one person paying a cost for another's benefit, is
    a fundamental principle without which no form of society could exist. The extent
    to which humans cooperate with each other is also an essential feature that differentiates
    them from other animals. Cooperation occurs even in the absence of altruistic
    motivations, when it is selfishly incentivised by the expectation of a future
    reward. For example, many economic interactions are well described that way. This
    kind of cooperation requires that people exhibit reciprocal behaviour that acts
    as a mechanism that rewards cooperation.\r\nWith game-theoretic models, it is
    possible to formally study potential such mechanisms and under what conditions
    they can exist. This thesis contributes to this effort by analysing recently introduced
    models of cooperation that advance on previous work by taking into account the
    potential for pre-existing inequality among cooperating individuals as well as
    the different forms that reciprocity can take.\r\nIndividuals may differ both
    intrinsically, in their abilities, as well as extrinsically, in the amount of
    resources they have available. Allowing for such differences in a model of cooperation
    helps to understand how inequality affects the potential for, and outcomes of,
    cooperation among unequals. In this thesis, it is shown that in the presence of
    intrinsic inequality, a similar unequal distribution of resources can increase
    the potential for cooperation. This effect is stronger the smaller the group is
    in which cooperation takes place. It is also shown that under particular assumptions,
    if the unequal members of a group vary the size of their contributions to a cooperative
    effort over time, they can thereby increase their efficiency and improve the collective
    outcome.\r\nCooperative behaviour in a two-person interaction can be rewarded
    either by direct reciprocation whenever the same two people interact again, or
    indirectly by a third party who observed the interaction. In the latter case of
    indirect reciprocity, individuals are proximally rewarded by a good reputation,
    which ultimately translates to being rewarded with cooperative behaviour by others.
    This mechanism can enable selfishly motivated cooperation even in circumstances
    where individuals are unlikely to meet again, akin to how money facilitates trade.
    While these two forms of reciprocity have mostly been studied in isolation, this
    thesis analyses both direct and indirect reciprocity in a general model in order
    to compare their relative effectiveness under different circumstances. The contribution
    of this thesis is an extension of previous work regarding a specific kind of interaction,
    whose parameters allow for convenient mathematical analysis, to the most general
    set of possible interactions."
acknowledgement: "The research for this thesis was supported by the European Research
  Council\r\n(grant agreements No. 863818 and No. 850529), the European Union’s Horizon
  2020 research and innovation programme (Marie Skłodowska-Curie grant agreement No.
  754411),\r\nthe Austrian Science Fund (grant DOI 10.55776/COE12), the French Agence
  Nationale\r\nde la Recherche under the Programme d’investissements d’avenir (project
  reference 17-\r\nEURE-0010) and the Australian Government through the Australian
  Research Council\r\n(grant No. SR200100005, “Securing Antarctica’s Environmental
  Future”)."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Valentin
  full_name: Hübner, Valentin
  id: 2c8aa207-dc7d-11ea-9b2f-f22972ecd910
  last_name: Hübner
  orcid: 0009-0001-5009-4987
citation:
  ama: Hübner V. Reciprocity and inequality in social dilemmas. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-19903">10.15479/AT-ISTA-19903</a>
  apa: Hübner, V. (2025). <i>Reciprocity and inequality in social dilemmas</i>. Institute
    of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-19903">https://doi.org/10.15479/AT-ISTA-19903</a>
  chicago: Hübner, Valentin. “Reciprocity and Inequality in Social Dilemmas.” Institute
    of Science and Technology Austria, 2025. <a href="https://doi.org/10.15479/AT-ISTA-19903">https://doi.org/10.15479/AT-ISTA-19903</a>.
  ieee: V. Hübner, “Reciprocity and inequality in social dilemmas,” Institute of Science
    and Technology Austria, 2025.
  ista: Hübner V. 2025. Reciprocity and inequality in social dilemmas. Institute of
    Science and Technology Austria.
  mla: Hübner, Valentin. <i>Reciprocity and Inequality in Social Dilemmas</i>. Institute
    of Science and Technology Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-19903">10.15479/AT-ISTA-19903</a>.
  short: V. Hübner, Reciprocity and Inequality in Social Dilemmas, Institute of Science
    and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-06-25T13:50:10Z
date_published: 2025-06-25T00:00:00Z
date_updated: 2026-04-07T12:30:57Z
day: '25'
ddc:
- '519'
degree_awarded: PhD
department:
- _id: GradSch
- _id: KrCh
doi: 10.15479/AT-ISTA-19903
ec_funded: 1
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month: '06'
oa: 1
oa_version: Published Version
page: '157'
project:
- _id: 0599E47C-7A3F-11EA-A408-12923DDC885E
  call_identifier: H2020
  grant_number: '863818'
  name: 'Formal Methods for Stochastic Models: Algorithms and Applications'
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  call_identifier: H2020
  grant_number: '754411'
  name: ISTplus - Postdoctoral Fellowships
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
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    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Krishnendu
  full_name: Chatterjee, Krishnendu
  id: 2E5DCA20-F248-11E8-B48F-1D18A9856A87
  last_name: Chatterjee
  orcid: 0000-0002-4561-241X
title: Reciprocity and inequality in social dilemmas
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type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
---
OA_place: publisher
_id: '20074'
abstract:
- lang: eng
  text: "Prenatal immune challenges pose significant risks to human embryonic brain
    and eye development. However, we still lack knowledge about the safe usage of
    anti-inflammatory drugs during pregnancy. Human induced pluripotent stem cell
    (hIPSC)-derived brain organoid models provide a unique opportunity to investigate
    neuronal development and have started to explore functional consequences upon
    viral infection. However, brain organoids usually lack microglia, the brain-resident
    immune cells. They are present in the early human embryonic brain and actively
    participate in neuronal circuit development. At the same time, microglia are known
    for their immune-sensing properties and will influence viral-mediated effects.
    In my thesis, I was interested to study the multifunctional role of human microglia
    during retinal development. \r\nIn chapter 1, I characterize the innate occurrence
    of IBA1+-microglia-like cells within the retinal organoid differentiation (Bartalska
    et al., 2022). Therefore, we differentiate hIPSC using an unguided retinal organoid
    differentiation protocol and observe the presence of IBA1+-microglia-like cells
    alongside retinal cups between week 3 and 4 in 2.5D culture. However, instead
    of infiltrating the neuroectodermal sides, they enrich within non-pigmented, 3D-cystic
    compartments that develop in low numbers parallel to 3D-retinal organoids. To
    enrich for IBA1+-microglia precursors (preMG), we guided the differentiation with
    a low-dosed BMP4 application, which prevents retinal cup development and enhances
    microglia and 3D-cysts formation. We characterize the differentiated preMG for
    their microglia-like identity and validated their functionality. In parallel,
    mass spectrometry identifies the 3D-cysts to express mesenchymal and epithelial
    markers. We confirm that comparable 3D-cysts are also the preferential environment
    for IBA1+-microglia-like cells within the unguided retinal organoid differentiation.
    \r\nIn chapter 2, I investigate how microglia influence retinal development and
    whether they contribute to viral-mediated consequences (Schmied et al., 2025).
    Here, we assemble preMG, which we have characterized in chapter 1, into 3D-retinal
    organoids. Once the outer plexiform layer forms, microglia-like cells (iMG) populate
    them and interact with retinal cell types. However, at this developmental stage,
    the ganglion cell number decreases in 3D-retinal organoids. Thus, we adapted the
    model into 2D which promotes their survival. Integrated iMG engulf ganglion cells
    and control their cell number. In parallel, we apply the immunostimulant POLY(I:C)
    to mimic a fetal viral infection. Although POLY(I:C) stimulation affects iMG phenotype,
    it does not influence their interaction with ganglion cells. Furthermore, iMG
    presence significantly contributes to the supernatant’s inflammatory secretome
    and increases retinal cell proliferation. Simultaneous exposure to the non-steroidal
    anti-inflammatory drug (NSAID) ibuprofen dampens POLY(I:C)-mediated consequences
    of the iMG phenotype and ameliorates cell proliferation. Remarkably, while POLY(I:C)
    disrupts neuronal calcium dynamics independent of iMG presence, ibuprofen rescues
    this effect only in the presence of iMG. Mechanistically, ibuprofen blocks the
    enzymes cyclooxygenase 1 and 2 (COX1/ PTGS1 and COX2/ PTGS2) simultaneously, from
    which iMG predominantly express COX1. Selective inhibition of COX1 does not restore
    the calcium peak amplitude upon POLY(I:C) stimulation, indicating ibuprofen’s
    effect depends on the presence and interplay of both, COX1 and COX2. \r\nIn summary,
    we characterized the 3D-retinal organoid model for the occurrence of IBA1+-microglia
    like cells. As the innately developing IBA1+-cells enrich in mesenchymal over
    retinal structures, we optimized a protocol to differentiate IBA1+-microglia precursors.
    By combining these two models we generate microglia-assembled retinal organoids.
    Our results underscore the importance of microglia during neurodevelopment, in
    the context of prenatal immune challenges and provide insight into the mechanisms
    by which ibuprofen exerts its protective effects during embryonic development."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Verena
  full_name: Hübschmann, Verena
  id: 32B7C918-F248-11E8-B48F-1D18A9856A87
  last_name: Hübschmann
citation:
  ama: Schmied V.  Human microglia impact neuronal development in retinal organoids.
    2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-20074">10.15479/AT-ISTA-20074</a>
  apa: Schmied, V. (2025). <i> Human microglia impact neuronal development in retinal
    organoids</i>. Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-20074">https://doi.org/10.15479/AT-ISTA-20074</a>
  chicago: Schmied, Verena. “ Human Microglia Impact Neuronal Development in Retinal
    Organoids.” Institute of Science and Technology Austria, 2025. <a href="https://doi.org/10.15479/AT-ISTA-20074">https://doi.org/10.15479/AT-ISTA-20074</a>.
  ieee: V. Schmied, “ Human microglia impact neuronal development in retinal organoids,”
    Institute of Science and Technology Austria, 2025.
  ista: Schmied V. 2025.  Human microglia impact neuronal development in retinal organoids.
    Institute of Science and Technology Austria.
  mla: Schmied, Verena. <i> Human Microglia Impact Neuronal Development in Retinal
    Organoids</i>. Institute of Science and Technology Austria, 2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-20074">10.15479/AT-ISTA-20074</a>.
  short: V. Schmied,  Human Microglia Impact Neuronal Development in Retinal Organoids,
    Institute of Science and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-07-24T12:37:22Z
date_published: 2025-07-24T00:00:00Z
date_updated: 2026-05-06T12:49:36Z
day: '24'
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degree_awarded: PhD
department:
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- _id: SaSi
doi: 10.15479/AT-ISTA-20074
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project:
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  grant_number: SC19-017
  name: How human microglia shape developing neurons during health and inflammation
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  issn:
  - 2663-337X
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publisher: Institute of Science and Technology Austria
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status: public
supervisor:
- first_name: Sandra
  full_name: Siegert, Sandra
  id: 36ACD32E-F248-11E8-B48F-1D18A9856A87
  last_name: Siegert
  orcid: 0000-0001-8635-0877
title: ' Human microglia impact neuronal development in retinal organoids'
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  short: CC BY (4.0)
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
---
OA_place: publisher
_id: '20117'
acknowledged_ssus:
- _id: Bio
- _id: LifeSc
- _id: PreCl
acknowledgement: "I would also like to acknowledge the invaluable assistance provided
  by the Plant\r\nFacility, Imaging & Optics Facility, and the Lab Support Facility.
  The technical support and\r\nresources offered by these facilities were indispensable
  to the successful completion of my\r\nexperiments."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Yiqun
  full_name: Wang, Yiqun
  id: 82F537F2-B517-11E9-84D7-6433E6697425
  last_name: Wang
citation:
  ama: Wang Y. The role of dynamin related protein 2A in cytokinin regulated plant
    growth and development. 2025. doi:<a href="https://doi.org/10.15479/AT-ISTA-20117">10.15479/AT-ISTA-20117</a>
  apa: Wang, Y. (2025). <i>The role of dynamin related protein 2A in cytokinin regulated
    plant growth and development</i>. Institute of Science and Technology Austria.
    <a href="https://doi.org/10.15479/AT-ISTA-20117">https://doi.org/10.15479/AT-ISTA-20117</a>
  chicago: Wang, Yiqun. “The Role of Dynamin Related Protein 2A in Cytokinin Regulated
    Plant Growth and Development.” Institute of Science and Technology Austria, 2025.
    <a href="https://doi.org/10.15479/AT-ISTA-20117">https://doi.org/10.15479/AT-ISTA-20117</a>.
  ieee: Y. Wang, “The role of dynamin related protein 2A in cytokinin regulated plant
    growth and development,” Institute of Science and Technology Austria, 2025.
  ista: Wang Y. 2025. The role of dynamin related protein 2A in cytokinin regulated
    plant growth and development. Institute of Science and Technology Austria.
  mla: Wang, Yiqun. <i>The Role of Dynamin Related Protein 2A in Cytokinin Regulated
    Plant Growth and Development</i>. Institute of Science and Technology Austria,
    2025, doi:<a href="https://doi.org/10.15479/AT-ISTA-20117">10.15479/AT-ISTA-20117</a>.
  short: Y. Wang, The Role of Dynamin Related Protein 2A in Cytokinin Regulated Plant
    Growth and Development, Institute of Science and Technology Austria, 2025.
corr_author: '1'
date_created: 2025-08-04T15:24:21Z
date_published: 2025-08-04T00:00:00Z
date_updated: 2026-04-07T11:49:34Z
day: '04'
ddc:
- '580'
degree_awarded: PhD
department:
- _id: GradSch
- _id: EvBe
doi: 10.15479/AT-ISTA-20117
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  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
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    status: public
status: public
supervisor:
- first_name: Eva
  full_name: Benková, Eva
  id: 38F4F166-F248-11E8-B48F-1D18A9856A87
  last_name: Benková
  orcid: 0000-0002-8510-9739
title: The role of dynamin related protein 2A in cytokinin regulated plant growth
  and development
type: dissertation
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
year: '2025'
...
