---
_id: '12976'
abstract:
- lang: eng
  text: "3D printing based on continuous deposition of materials, such as filament-based
    3D printing, has seen widespread adoption thanks to its versatility in working
    with a wide range of materials. An important shortcoming of this type of technology
    is its limited multi-material capabilities. While there are simple hardware designs
    that enable multi-material printing in principle, the required software is heavily
    underdeveloped. A typical hardware design fuses together individual materials
    fed into a single chamber from multiple inlets before they are deposited. This
    design, however, introduces a time delay between the intended material mixture
    and its actual deposition. In this work, inspired by diverse path planning research
    in robotics, we show that this mechanical challenge can be addressed via improved
    printer control. We propose to formulate the search for optimal multi-material
    printing policies in a reinforcement\r\nlearning setup. We put forward a simple
    numerical deposition model that takes into account the non-linear material mixing
    and delayed material deposition. To validate our system we focus on color fabrication,
    a problem known for its strict requirements for varying material mixtures at a
    high spatial frequency. We demonstrate that our learned control policy outperforms
    state-of-the-art hand-crafted algorithms."
acknowledgement: This work is graciously supported by FWF Lise Meitner (Grant M 3319).
  Kang Liao sincerely thank Emiliano Luci, Chunyu Lin, and Yao Zhao for their huge
  support.
article_processing_charge: No
author:
- first_name: Kang
  full_name: Liao, Kang
  last_name: Liao
- first_name: Thibault
  full_name: Tricard, Thibault
  last_name: Tricard
- first_name: Michael
  full_name: Piovarci, Michael
  id: 62E473F4-5C99-11EA-A40E-AF823DDC885E
  last_name: Piovarci
  orcid: 0000-0002-5062-4474
- first_name: Hans-Peter
  full_name: Seidel, Hans-Peter
  last_name: Seidel
- first_name: Vahid
  full_name: Babaei, Vahid
  last_name: Babaei
citation:
  ama: 'Liao K, Tricard T, Piovarci M, Seidel H-P, Babaei V. Learning deposition policies
    for fused multi-material 3D printing. In: <i>2023 IEEE International Conference
    on Robotics and Automation</i>. Vol 2023. IEEE; 2023:12345-12352. doi:<a href="https://doi.org/10.1109/ICRA48891.2023.10160465">10.1109/ICRA48891.2023.10160465</a>'
  apa: 'Liao, K., Tricard, T., Piovarci, M., Seidel, H.-P., &#38; Babaei, V. (2023).
    Learning deposition policies for fused multi-material 3D printing. In <i>2023
    IEEE International Conference on Robotics and Automation</i> (Vol. 2023, pp. 12345–12352).
    London, United Kingdom: IEEE. <a href="https://doi.org/10.1109/ICRA48891.2023.10160465">https://doi.org/10.1109/ICRA48891.2023.10160465</a>'
  chicago: Liao, Kang, Thibault Tricard, Michael Piovarci, Hans-Peter Seidel, and
    Vahid Babaei. “Learning Deposition Policies for Fused Multi-Material 3D Printing.”
    In <i>2023 IEEE International Conference on Robotics and Automation</i>, 2023:12345–52.
    IEEE, 2023. <a href="https://doi.org/10.1109/ICRA48891.2023.10160465">https://doi.org/10.1109/ICRA48891.2023.10160465</a>.
  ieee: K. Liao, T. Tricard, M. Piovarci, H.-P. Seidel, and V. Babaei, “Learning deposition
    policies for fused multi-material 3D printing,” in <i>2023 IEEE International
    Conference on Robotics and Automation</i>, London, United Kingdom, 2023, vol.
    2023, pp. 12345–12352.
  ista: 'Liao K, Tricard T, Piovarci M, Seidel H-P, Babaei V. 2023. Learning deposition
    policies for fused multi-material 3D printing. 2023 IEEE International Conference
    on Robotics and Automation. ICRA: International Conference on Robotics and Automation
    vol. 2023, 12345–12352.'
  mla: Liao, Kang, et al. “Learning Deposition Policies for Fused Multi-Material 3D
    Printing.” <i>2023 IEEE International Conference on Robotics and Automation</i>,
    vol. 2023, IEEE, 2023, pp. 12345–52, doi:<a href="https://doi.org/10.1109/ICRA48891.2023.10160465">10.1109/ICRA48891.2023.10160465</a>.
  short: K. Liao, T. Tricard, M. Piovarci, H.-P. Seidel, V. Babaei, in:, 2023 IEEE
    International Conference on Robotics and Automation, IEEE, 2023, pp. 12345–12352.
conference:
  end_date: 2023-06-02
  location: London, United Kingdom
  name: 'ICRA: International Conference on Robotics and Automation'
  start_date: 2023-05-29
date_created: 2023-05-16T09:14:09Z
date_published: 2023-07-04T00:00:00Z
date_updated: 2023-12-13T11:20:00Z
day: '04'
ddc:
- '004'
department:
- _id: BeBi
doi: 10.1109/ICRA48891.2023.10160465
external_id:
  isi:
  - '001048371104068'
file:
- access_level: open_access
  checksum: daeaa67124777d88487f933ea3f77164
  content_type: application/pdf
  creator: mpiovarc
  date_created: 2023-05-16T09:12:05Z
  date_updated: 2023-05-16T09:12:05Z
  file_id: '12977'
  file_name: Liao2023.pdf
  file_size: 5367986
  relation: main_file
  success: 1
file_date_updated: 2023-05-16T09:12:05Z
has_accepted_license: '1'
intvolume: '      2023'
isi: 1
keyword:
- reinforcement learning
- deposition
- control
- color
- multi-filament
language:
- iso: eng
month: '07'
oa: 1
oa_version: Submitted Version
page: 12345-12352
project:
- _id: eb901961-77a9-11ec-83b8-f5c883a62027
  grant_number: M03319
  name: Perception-Aware Appearance Fabrication
publication: 2023 IEEE International Conference on Robotics and Automation
publication_identifier:
  eisbn:
  - '9798350323658'
  issn:
  - 1050-4729
publication_status: published
publisher: IEEE
quality_controlled: '1'
scopus_import: '1'
status: public
title: Learning deposition policies for fused multi-material 3D printing
type: conference
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2023
year: '2023'
...
---
_id: '11343'
abstract:
- lang: eng
  text: Multistable systems are characterized by exhibiting domain coexistence, where
    each domain accounts for the different equilibrium states. In case these systems
    are described by vectorial fields, domains can be connected through topological
    defects. Vortices are one of the most frequent and studied topological defect
    points. Optical vortices are equally relevant for their fundamental features as
    beams with topological features and their applications in image processing, telecommunications,
    optical tweezers, and quantum information. A natural source of optical vortices
    is the interaction of light beams with matter vortices in liquid crystal cells.
    The rhythms that govern the emergence of matter vortices due to fluctuations are
    not established. Here, we investigate the nucleation mechanisms of the matter
    vortices in liquid crystal cells and establish statistical laws that govern them.
    Based on a stochastic amplitude equation, the law for the number of nucleated
    vortices as a function of anisotropy, voltage, and noise level intensity is set.
    Experimental observations in a nematic liquid crystal cell with homeotropic anchoring
    and a negative anisotropic dielectric constant under the influence of a transversal
    electric field show a qualitative agreement with the theoretical findings.
acknowledgement: "The authors thank Enrique Calisto,Michal Kowalczyk, and Michel Ferre
  for fructified discussions. This work was funded by ANID—Millennium Science Initiative
  Program—ICN17_012. MGC is thankful for financial support from the Fondecyt 1210353
  project.\r\nOpen access funding provided by Institute of Science and Technology
  (IST Austria)."
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Esteban
  full_name: Aguilera, Esteban
  last_name: Aguilera
- first_name: Marcel G.
  full_name: Clerc, Marcel G.
  last_name: Clerc
- first_name: Valeska
  full_name: Zambra, Valeska
  id: 467ed36b-dc96-11ea-b7c8-b043a380b282
  last_name: Zambra
citation:
  ama: Aguilera E, Clerc MG, Zambra V. Vortices nucleation by inherent fluctuations
    in nematic liquid crystal cells. <i>Nonlinear Dynamics</i>. 2022;108:3209-3218.
    doi:<a href="https://doi.org/10.1007/s11071-022-07396-5">10.1007/s11071-022-07396-5</a>
  apa: Aguilera, E., Clerc, M. G., &#38; Zambra, V. (2022). Vortices nucleation by
    inherent fluctuations in nematic liquid crystal cells. <i>Nonlinear Dynamics</i>.
    Springer Nature. <a href="https://doi.org/10.1007/s11071-022-07396-5">https://doi.org/10.1007/s11071-022-07396-5</a>
  chicago: Aguilera, Esteban, Marcel G. Clerc, and Valeska Zambra. “Vortices Nucleation
    by Inherent Fluctuations in Nematic Liquid Crystal Cells.” <i>Nonlinear Dynamics</i>.
    Springer Nature, 2022. <a href="https://doi.org/10.1007/s11071-022-07396-5">https://doi.org/10.1007/s11071-022-07396-5</a>.
  ieee: E. Aguilera, M. G. Clerc, and V. Zambra, “Vortices nucleation by inherent
    fluctuations in nematic liquid crystal cells,” <i>Nonlinear Dynamics</i>, vol.
    108. Springer Nature, pp. 3209–3218, 2022.
  ista: Aguilera E, Clerc MG, Zambra V. 2022. Vortices nucleation by inherent fluctuations
    in nematic liquid crystal cells. Nonlinear Dynamics. 108, 3209–3218.
  mla: Aguilera, Esteban, et al. “Vortices Nucleation by Inherent Fluctuations in
    Nematic Liquid Crystal Cells.” <i>Nonlinear Dynamics</i>, vol. 108, Springer Nature,
    2022, pp. 3209–18, doi:<a href="https://doi.org/10.1007/s11071-022-07396-5">10.1007/s11071-022-07396-5</a>.
  short: E. Aguilera, M.G. Clerc, V. Zambra, Nonlinear Dynamics 108 (2022) 3209–3218.
date_created: 2022-05-02T07:01:59Z
date_published: 2022-06-01T00:00:00Z
date_updated: 2023-08-03T06:46:54Z
day: '01'
ddc:
- '530'
department:
- _id: KiMo
doi: 10.1007/s11071-022-07396-5
external_id:
  isi:
  - '000784871800001'
file:
- access_level: open_access
  checksum: 7d80cdece4e1b1c2106e6772a9622f60
  content_type: application/pdf
  creator: dernst
  date_created: 2022-08-05T06:13:19Z
  date_updated: 2022-08-05T06:13:19Z
  file_id: '11728'
  file_name: 2022_NonlinearDyn_Aguilera.pdf
  file_size: 1416049
  relation: main_file
  success: 1
file_date_updated: 2022-08-05T06:13:19Z
has_accepted_license: '1'
intvolume: '       108'
isi: 1
keyword:
- Electrical and Electronic Engineering
- Applied Mathematics
- Mechanical Engineering
- Ocean Engineering
- Aerospace Engineering
- Control and Systems Engineering
language:
- iso: eng
month: '06'
oa: 1
oa_version: Published Version
page: 3209-3218
publication: Nonlinear Dynamics
publication_identifier:
  eissn:
  - 1573-269X
  issn:
  - 0924-090X
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Vortices nucleation by inherent fluctuations in nematic liquid crystal cells
tmp:
  image: /images/cc_by.png
  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: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 108
year: '2022'
...
---
_id: '11683'
abstract:
- lang: eng
  text: The vertex connectivity κ of a graph is the smallest number of vertices whose
    deletion separates the graph or makes it trivial. We present the fastest known
    deterministic algorithm for finding the vertex connectivity and a corresponding
    separator. The time for a digraph having n vertices and m edges is O(min{κ3 +
    n, κn}m); for an undirected graph the term m can be replaced by κn. A randomized
    algorithm finds κ with error probability 1/2 in time O(nm). If the vertices have
    nonnegative weights the weighted vertex connectivity is found in time O(κ1nmlog(n2/m))
    where κ1 ≤ m/n is the unweighted vertex connectivity or in expected time O(nmlog(n2/m))
    with error probability 1/2. The main algorithm combines two previous vertex connectivity
    algorithms and a generalization of the preflow-push algorithm of Hao and Orlin
    (1994, J. Algorithms17, 424–446) that computes edge connectivity.
article_processing_charge: No
article_type: original
author:
- first_name: Monika H
  full_name: Henzinger, Monika H
  id: 540c9bbd-f2de-11ec-812d-d04a5be85630
  last_name: Henzinger
  orcid: 0000-0002-5008-6530
- first_name: Satish
  full_name: Rao, Satish
  last_name: Rao
- first_name: Harold N.
  full_name: Gabow, Harold N.
  last_name: Gabow
citation:
  ama: 'Henzinger MH, Rao S, Gabow HN. Computing vertex connectivity: New bounds from
    old techniques. <i>Journal of Algorithms</i>. 2000;34(2):222-250. doi:<a href="https://doi.org/10.1006/jagm.1999.1055">10.1006/jagm.1999.1055</a>'
  apa: 'Henzinger, M. H., Rao, S., &#38; Gabow, H. N. (2000). Computing vertex connectivity:
    New bounds from old techniques. <i>Journal of Algorithms</i>. Elsevier. <a href="https://doi.org/10.1006/jagm.1999.1055">https://doi.org/10.1006/jagm.1999.1055</a>'
  chicago: 'Henzinger, Monika H, Satish Rao, and Harold N. Gabow. “Computing Vertex
    Connectivity: New Bounds from Old Techniques.” <i>Journal of Algorithms</i>. Elsevier,
    2000. <a href="https://doi.org/10.1006/jagm.1999.1055">https://doi.org/10.1006/jagm.1999.1055</a>.'
  ieee: 'M. H. Henzinger, S. Rao, and H. N. Gabow, “Computing vertex connectivity:
    New bounds from old techniques,” <i>Journal of Algorithms</i>, vol. 34, no. 2.
    Elsevier, pp. 222–250, 2000.'
  ista: 'Henzinger MH, Rao S, Gabow HN. 2000. Computing vertex connectivity: New bounds
    from old techniques. Journal of Algorithms. 34(2), 222–250.'
  mla: 'Henzinger, Monika H., et al. “Computing Vertex Connectivity: New Bounds from
    Old Techniques.” <i>Journal of Algorithms</i>, vol. 34, no. 2, Elsevier, 2000,
    pp. 222–50, doi:<a href="https://doi.org/10.1006/jagm.1999.1055">10.1006/jagm.1999.1055</a>.'
  short: M.H. Henzinger, S. Rao, H.N. Gabow, Journal of Algorithms 34 (2000) 222–250.
date_created: 2022-07-28T08:56:10Z
date_published: 2000-02-01T00:00:00Z
date_updated: 2022-09-12T09:06:48Z
day: '01'
doi: 10.1006/jagm.1999.1055
extern: '1'
intvolume: '        34'
issue: '2'
keyword:
- Computational Theory and Mathematics
- Computational Mathematics
- Control and Optimization
language:
- iso: eng
month: '02'
oa_version: None
page: 222-250
publication: Journal of Algorithms
publication_identifier:
  issn:
  - 0196-6774
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'Computing vertex connectivity: New bounds from old techniques'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 34
year: '2000'
...