---
_id: '46649'
abstract:
- lang: eng
  text: "Different conflicting optimization criteria arise naturally in various Deep\r\nLearning
    scenarios. These can address different main tasks (i.e., in the\r\nsetting of
    Multi-Task Learning), but also main and secondary tasks such as loss\r\nminimization
    versus sparsity. The usual approach is a simple weighting of the\r\ncriteria,
    which formally only works in the convex setting. In this paper, we\r\npresent
    a Multi-Objective Optimization algorithm using a modified Weighted\r\nChebyshev
    scalarization for training Deep Neural Networks (DNNs) with respect\r\nto several
    tasks. By employing this scalarization technique, the algorithm can\r\nidentify
    all optimal solutions of the original problem while reducing its\r\ncomplexity
    to a sequence of single-objective problems. The simplified problems\r\nare then
    solved using an Augmented Lagrangian method, enabling the use of\r\npopular optimization
    techniques such as Adam and Stochastic Gradient Descent,\r\nwhile efficaciously
    handling constraints. Our work aims to address the\r\n(economical and also ecological)
    sustainability issue of DNN models, with a\r\nparticular focus on Deep Multi-Task
    models, which are typically designed with a\r\nvery large number of weights to
    perform equally well on multiple tasks. Through\r\nexperiments conducted on two
    Machine Learning datasets, we demonstrate the\r\npossibility of adaptively sparsifying
    the model during training without\r\nsignificantly impacting its performance,
    if we are willing to apply\r\ntask-specific adaptations to the network weights.
    Code is available at\r\nhttps://github.com/salomonhotegni/MDMTN."
author:
- first_name: Sedjro Salomon
  full_name: Hotegni, Sedjro Salomon
  id: '97995'
  last_name: Hotegni
- first_name: Manuel Bastian
  full_name: Berkemeier, Manuel Bastian
  id: '51701'
  last_name: Berkemeier
- first_name: Sebastian
  full_name: Peitz, Sebastian
  id: '47427'
  last_name: Peitz
  orcid: 0000-0002-3389-793X
citation:
  ama: 'Hotegni SS, Berkemeier MB, Peitz S. Multi-Objective Optimization for Sparse
    Deep Multi-Task Learning. In: <i>2024 International Joint Conference on Neural
    Networks (IJCNN)</i>. IEEE; 2024:9. doi:<a href="https://doi.org/10.1109/IJCNN60899.2024.10650994">10.1109/IJCNN60899.2024.10650994</a>'
  apa: Hotegni, S. S., Berkemeier, M. B., &#38; Peitz, S. (2024). Multi-Objective
    Optimization for Sparse Deep Multi-Task Learning. <i>2024 International Joint
    Conference on Neural Networks (IJCNN)</i>, 9. <a href="https://doi.org/10.1109/IJCNN60899.2024.10650994">https://doi.org/10.1109/IJCNN60899.2024.10650994</a>
  bibtex: '@inproceedings{Hotegni_Berkemeier_Peitz_2024, place={Yokohama, Japan},
    title={Multi-Objective Optimization for Sparse Deep Multi-Task Learning}, DOI={<a
    href="https://doi.org/10.1109/IJCNN60899.2024.10650994">10.1109/IJCNN60899.2024.10650994</a>},
    booktitle={2024 International Joint Conference on Neural Networks (IJCNN)}, publisher={IEEE},
    author={Hotegni, Sedjro Salomon and Berkemeier, Manuel Bastian and Peitz, Sebastian},
    year={2024}, pages={9} }'
  chicago: 'Hotegni, Sedjro Salomon, Manuel Bastian Berkemeier, and Sebastian Peitz.
    “Multi-Objective Optimization for Sparse Deep Multi-Task Learning.” In <i>2024
    International Joint Conference on Neural Networks (IJCNN)</i>, 9. Yokohama, Japan:
    IEEE, 2024. <a href="https://doi.org/10.1109/IJCNN60899.2024.10650994">https://doi.org/10.1109/IJCNN60899.2024.10650994</a>.'
  ieee: 'S. S. Hotegni, M. B. Berkemeier, and S. Peitz, “Multi-Objective Optimization
    for Sparse Deep Multi-Task Learning,” in <i>2024 International Joint Conference
    on Neural Networks (IJCNN)</i>, Yokohama, Japan, 2024, p. 9, doi: <a href="https://doi.org/10.1109/IJCNN60899.2024.10650994">10.1109/IJCNN60899.2024.10650994</a>.'
  mla: Hotegni, Sedjro Salomon, et al. “Multi-Objective Optimization for Sparse Deep
    Multi-Task Learning.” <i>2024 International Joint Conference on Neural Networks
    (IJCNN)</i>, IEEE, 2024, p. 9, doi:<a href="https://doi.org/10.1109/IJCNN60899.2024.10650994">10.1109/IJCNN60899.2024.10650994</a>.
  short: 'S.S. Hotegni, M.B. Berkemeier, S. Peitz, in: 2024 International Joint Conference
    on Neural Networks (IJCNN), IEEE, Yokohama, Japan, 2024, p. 9.'
conference:
  end_date: 2024-07-05
  location: Yokohama, Japan
  name: 2024 International Joint Conference on Neural Networks (IJCNN)
  start_date: 2024-06-30
date_created: 2023-08-24T07:44:36Z
date_updated: 2024-09-27T10:24:22Z
department:
- _id: '655'
doi: 10.1109/IJCNN60899.2024.10650994
has_accepted_license: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://ieeexplore.ieee.org/document/10650994
oa: '1'
page: '9'
place: Yokohama, Japan
publication: 2024 International Joint Conference on Neural Networks (IJCNN)
publication_identifier:
  eisbn:
  - 979-8-3503-5931-2
  eissn:
  - ' 2161-4407'
publication_status: published
publisher: IEEE
status: public
title: Multi-Objective Optimization for Sparse Deep Multi-Task Learning
type: conference
user_id: '97995'
year: '2024'
...
---
_id: '33150'
abstract:
- lang: eng
  text: In this article, we build on previous work to present an optimization algorithm
    for nonlinearly constrained multi-objective optimization problems. The algorithm
    combines a surrogate-assisted derivative-free trust-region approach with the filter
    method known from single-objective optimization. Instead of the true objective
    and constraint functions, so-called fully linear models are employed and we show
    how to deal with the gradient inexactness in the composite step setting, adapted
    from single-objective optimization as well. Under standard assumptions, we prove
    convergence of a subset of iterates to a quasi-stationary point and if constraint
    qualifications hold, then the limit point is also a KKT-point of the multi-objective
    problem.
author:
- first_name: Manuel Bastian
  full_name: Berkemeier, Manuel Bastian
  id: '51701'
  last_name: Berkemeier
- first_name: Sebastian
  full_name: Peitz, Sebastian
  id: '47427'
  last_name: Peitz
  orcid: 0000-0002-3389-793X
citation:
  ama: Berkemeier MB, Peitz S. Multi-Objective Trust-Region Filter Method for Nonlinear
    Constraints using Inexact Gradients. <i>arXiv:220812094</i>. Published online
    2022.
  apa: Berkemeier, M. B., &#38; Peitz, S. (2022). Multi-Objective Trust-Region Filter
    Method for Nonlinear Constraints using Inexact Gradients. In <i>arXiv:2208.12094</i>.
  bibtex: '@article{Berkemeier_Peitz_2022, title={Multi-Objective Trust-Region Filter
    Method for Nonlinear Constraints using Inexact Gradients}, journal={arXiv:2208.12094},
    author={Berkemeier, Manuel Bastian and Peitz, Sebastian}, year={2022} }'
  chicago: Berkemeier, Manuel Bastian, and Sebastian Peitz. “Multi-Objective Trust-Region
    Filter Method for Nonlinear Constraints Using Inexact Gradients.” <i>ArXiv:2208.12094</i>,
    2022.
  ieee: M. B. Berkemeier and S. Peitz, “Multi-Objective Trust-Region Filter Method
    for Nonlinear Constraints using Inexact Gradients,” <i>arXiv:2208.12094</i>. 2022.
  mla: Berkemeier, Manuel Bastian, and Sebastian Peitz. “Multi-Objective Trust-Region
    Filter Method for Nonlinear Constraints Using Inexact Gradients.” <i>ArXiv:2208.12094</i>,
    2022.
  short: M.B. Berkemeier, S. Peitz, ArXiv:2208.12094 (2022).
date_created: 2022-08-26T06:08:06Z
date_updated: 2022-08-26T06:12:10Z
department:
- _id: '101'
- _id: '655'
external_id:
  arxiv:
  - '2208.12094'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/pdf/2208.12094
oa: '1'
publication: arXiv:2208.12094
status: public
title: Multi-Objective Trust-Region Filter Method for Nonlinear Constraints using
  Inexact Gradients
type: preprint
user_id: '47427'
year: '2022'
...
---
_id: '21337'
abstract:
- lang: eng
  text: "We present a flexible trust region descend algorithm for unconstrained and\r\nconvexly
    constrained multiobjective optimization problems. It is targeted at\r\nheterogeneous
    and expensive problems, i.e., problems that have at least one\r\nobjective function
    that is computationally expensive. The method is\r\nderivative-free in the sense
    that neither need derivative information be\r\navailable for the expensive objectives
    nor are gradients approximated using\r\nrepeated function evaluations as is the
    case in finite-difference methods.\r\nInstead, a multiobjective trust region approach
    is used that works similarly to\r\nits well-known scalar pendants. Local surrogate
    models constructed from\r\nevaluation data of the true objective functions are
    employed to compute\r\npossible descent directions. In contrast to existing multiobjective
    trust\r\nregion algorithms, these surrogates are not polynomial but carefully\r\nconstructed
    radial basis function networks. This has the important advantage\r\nthat the number
    of data points scales linearly with the parameter space\r\ndimension. The local
    models qualify as fully linear and the corresponding\r\ngeneral scalar framework
    is adapted for problems with multiple objectives.\r\nConvergence to Pareto critical
    points is proven and numerical examples\r\nillustrate our findings."
article_number: '31'
author:
- first_name: Manuel Bastian
  full_name: Berkemeier, Manuel Bastian
  id: '51701'
  last_name: Berkemeier
- first_name: Sebastian
  full_name: Peitz, Sebastian
  id: '47427'
  last_name: Peitz
  orcid: 0000-0002-3389-793X
citation:
  ama: Berkemeier MB, Peitz S. Derivative-Free Multiobjective Trust Region Descent
    Method Using Radial  Basis Function Surrogate Models. <i>Mathematical and Computational
    Applications</i>. 2021;26(2). doi:<a href="https://doi.org/10.3390/mca26020031">10.3390/mca26020031</a>
  apa: Berkemeier, M. B., &#38; Peitz, S. (2021). Derivative-Free Multiobjective Trust
    Region Descent Method Using Radial  Basis Function Surrogate Models. <i>Mathematical
    and Computational Applications</i>, <i>26</i>(2). <a href="https://doi.org/10.3390/mca26020031">https://doi.org/10.3390/mca26020031</a>
  bibtex: '@article{Berkemeier_Peitz_2021, title={Derivative-Free Multiobjective Trust
    Region Descent Method Using Radial  Basis Function Surrogate Models}, volume={26},
    DOI={<a href="https://doi.org/10.3390/mca26020031">10.3390/mca26020031</a>}, number={231},
    journal={Mathematical and Computational Applications}, author={Berkemeier, Manuel
    Bastian and Peitz, Sebastian}, year={2021} }'
  chicago: Berkemeier, Manuel Bastian, and Sebastian Peitz. “Derivative-Free Multiobjective
    Trust Region Descent Method Using Radial  Basis Function Surrogate Models.” <i>Mathematical
    and Computational Applications</i> 26, no. 2 (2021). <a href="https://doi.org/10.3390/mca26020031">https://doi.org/10.3390/mca26020031</a>.
  ieee: M. B. Berkemeier and S. Peitz, “Derivative-Free Multiobjective Trust Region
    Descent Method Using Radial  Basis Function Surrogate Models,” <i>Mathematical
    and Computational Applications</i>, vol. 26, no. 2, 2021.
  mla: Berkemeier, Manuel Bastian, and Sebastian Peitz. “Derivative-Free Multiobjective
    Trust Region Descent Method Using Radial  Basis Function Surrogate Models.” <i>Mathematical
    and Computational Applications</i>, vol. 26, no. 2, 31, 2021, doi:<a href="https://doi.org/10.3390/mca26020031">10.3390/mca26020031</a>.
  short: M.B. Berkemeier, S. Peitz, Mathematical and Computational Applications 26
    (2021).
date_created: 2021-03-01T10:46:48Z
date_updated: 2022-01-06T06:54:55Z
department:
- _id: '101'
- _id: '655'
doi: 10.3390/mca26020031
intvolume: '        26'
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://www.mdpi.com/2297-8747/26/2/31/pdf
oa: '1'
publication: Mathematical and Computational Applications
publication_identifier:
  eissn:
  - 2297-8747
publication_status: published
status: public
title: Derivative-Free Multiobjective Trust Region Descent Method Using Radial  Basis
  Function Surrogate Models
type: journal_article
user_id: '47427'
volume: 26
year: '2021'
...
