https://www.mdu.se/

mdu.sePublications
System disruptions
There are recurring service disruptions on some of the search portals due to high traffic. We are working to resolve the issue, you may temporarily encounter an error message.
Change search
Link to record
Permanent link

Direct link
Westerback, Thomas
Publications (7 of 7) Show all publications
Fiaschi, G., Vitucci, C., Westerback, T., Sundmark, D. & Nolte, T. (2026). Methods for Path Set Attribute Calculation in Network Systems. In: Proceedings of the 2026 IEEE International Conference on Computer, Information, and Telecommunication Systems, CITS 2026: . Paper presented at 2026 IEEE International Conference on Computer, Information, and Telecommunication Systems, CITS 2026, 22-24 June 2026, Piraeus-Athens, Greece. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Methods for Path Set Attribute Calculation in Network Systems
Show others...
2026 (English)In: Proceedings of the 2026 IEEE International Conference on Computer, Information, and Telecommunication Systems, CITS 2026, Institute of Electrical and Electronics Engineers (IEEE) , 2026Conference paper, Published paper (Refereed)
Abstract [en]

In graph theory and its applications to networking, such as telecommunications or transportation, path-finding is a central problem. While single-path algorithms are well established, methods for handling sets of multiple paths are less developed. A companion paper introduced a formal model for defining attributes over sets of paths based on their structural properties; this paper addresses that model's practical implementation. We present an optimized algorithm for computing cut sets of a path set - a nontrivial task that can be infeasible without efficient methods - and validate its performance via systematic benchmarks on network simulations of varying complexity. Additionally, we introduce a vectorized computational framework that expresses property calculations as matrix operations, enabling concise implementations in array-oriented languages. Together, these contributions establish practical foundations for the companion model, demonstrating that its implementation is both feasible and characterized by predictable, acceptable execution times.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2026
Keywords
Error Probability;, Network optimization, Path set characterization, Routing, Graph theory, Error probabilities, Graph theory applications, In networks, Network systems, Path set, Property, Routings, Benchmarking
National Category
Computer Sciences
Identifiers
urn:nbn:se:mdh:diva-78919 (URN)10.1109/CITS70307.2026.11637265 (DOI)2-s2.0-105048344569 (Scopus ID)9798319529589 (ISBN)
Conference
2026 IEEE International Conference on Computer, Information, and Telecommunication Systems, CITS 2026, 22-24 June 2026, Piraeus-Athens, Greece
Available from: 2026-09-04 Created: 2026-09-04 Last updated: 2026-09-04Bibliographically approved
Fiaschi, G., Vitucci, C., Westerback, T., Sundmark, D. & Nolte, T. (2025). A Formal Model for Path Set Attribute Calculation in Network Systems. In: 2025 International Symposium on Networks, Computers and Communications (ISNCC): . Paper presented at 2025 International Symposium on Networks, Computers and Communications (ISNCC) (pp. 1-8). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>A Formal Model for Path Set Attribute Calculation in Network Systems
Show others...
2025 (English)In: 2025 International Symposium on Networks, Computers and Communications (ISNCC), Institute of Electrical and Electronics Engineers (IEEE) , 2025, p. 1-8Conference paper, Published paper (Refereed)
Abstract [en]

In graph theory and its practical networking applications, e.g., telecommunications and transportation, the problem of finding paths has particular importance. Selecting paths requires giving scores to the alternative solutions to drive a choice. While previous studies have provided comprehensive evaluation of single-path solutions, the same level of detail is lacking when considering sets of paths. This paper emphasizes that the path characterization strongly depends on the properties under consideration. While property-based characterization is also valid for single paths, it becomes crucial to analyse multiple path sets. From the above consideration, this paper proposes a mathematical approach, defining a functional model that lends itself well to characterizing the path set in its general formulation. The paper shows how the functional model contextualizes specific attributes.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2025
Series
International Symposium on Networks, Computers and Communications, ISSN 2768-0940
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:mdh:diva-74717 (URN)10.1109/isncc66965.2025.11250449 (DOI)2-s2.0-105031405278 (Scopus ID)978-1-6654-5769-9 (ISBN)
Conference
2025 International Symposium on Networks, Computers and Communications (ISNCC)
Funder
Knowledge Foundation
Available from: 2025-12-02 Created: 2025-12-02 Last updated: 2026-03-11Bibliographically approved
Vitucci, C., Westerback, T., Sundmark, D., Forsberg, H., Nolte, T. & Jägemar, M. (2024). A Deductive Fault Analysis Method Based on Hypergraphs. In: IFAC-PapersOnLine: . Paper presented at 12th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2024: Ferrara, Italy, June 4 – 7, 2024 (pp. 378-383). Elsevier B.V. (4)
Open this publication in new window or tab >>A Deductive Fault Analysis Method Based on Hypergraphs
Show others...
2024 (English)In: IFAC-PapersOnLine, Elsevier B.V. , 2024, no 4, p. 378-383Conference paper, Published paper (Refereed)
Abstract [en]

Fault tree analysis is a system malfunction hazard evaluation quantitative and qualitative procedure. The method is well-known and widely used, especially in the safety systems domain, where it is a mandatory integral part of the so-called "Hazard Evaluation"documentation. This paper proposes an alternative or complementary deductive fault analysis method: it uses system topology to build a hypergraph representation of the system to identify component criticality and support loss of functionality probability evaluation. Once automated, the proposed method seems promising when the system engineers explore the different architectures. They may have indication about architecture's reliability without continuous feedback from the system safety team. The system safety team must check the solution once the engineers select the final architecture. They can also use the proposed method to validate the correctness of the fault tree analysis.

Place, publisher, year, edition, pages
Elsevier B.V., 2024
Series
IFAC-PapersOnLine, ISSN 2405-8963
Keywords
cut set level, fault analysis, hypergraph, loss of function probability, Accident prevention, Hazards, Reliability analysis, Trees (mathematics), Cut sets, Fault analysis methods, Fault tree analyses (FTA), Hazard evaluation, Hyper graph, System domain, System safety, Fault tree analysis
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:mdh:diva-68416 (URN)10.1016/j.ifacol.2024.07.247 (DOI)001296047100064 ()2-s2.0-85202861493 (Scopus ID)
Conference
12th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2024: Ferrara, Italy, June 4 – 7, 2024
Available from: 2024-09-11 Created: 2024-09-11 Last updated: 2025-10-10Bibliographically approved
Freij-Hollanti, R., Grezet, M., Hollanti, C. & Westerback, T. (2021). Cyclic flats of binary matroids. Advances in Applied Mathematics, 127, Article ID 102165.
Open this publication in new window or tab >>Cyclic flats of binary matroids
2021 (English)In: Advances in Applied Mathematics, ISSN 0196-8858, E-ISSN 1090-2074, Vol. 127, article id 102165Article in journal (Refereed) Published
Abstract [en]

In this paper, first steps are taken towards characterizing rank-decorated lattices of cyclic flats Z(M) that belong to matroids M that can be represented over a prescribed finite field F-q. Two natural maps from Z(M) to the lattice of cyclic flats of a minor of M are given. Binary matroids are characterized via their lattice of cyclic flats. It is shown that the lattice of cyclic flats of a simple binary matroid without isthmuses is atomic.

Place, publisher, year, edition, pages
ACADEMIC PRESS INC ELSEVIER SCIENCE, 2021
Keywords
Cyclic flats, Binary matroids, Atomic lattices
National Category
Probability Theory and Statistics
Identifiers
urn:nbn:se:mdh:diva-54126 (URN)10.1016/j.aam.2021.102165 (DOI)000636081100005 ()2-s2.0-85100033597 (Scopus ID)
Available from: 2021-05-10 Created: 2021-05-10 Last updated: 2025-10-10Bibliographically approved
Grezet, M., Freij-Hollanti, R., Westerback, T. & Hollanti, C. (2019). Alphabet-Dependent Bounds for Linear Locally Repairable Codes Based on Residual Codes. IEEE Transactions on Information Theory, 65(10), 6089-6100, Article ID 8700214.
Open this publication in new window or tab >>Alphabet-Dependent Bounds for Linear Locally Repairable Codes Based on Residual Codes
2019 (English)In: IEEE Transactions on Information Theory, ISSN 0018-9448, E-ISSN 1557-9654, Vol. 65, no 10, p. 6089-6100, article id 8700214Article in journal (Refereed) Published
Abstract [en]

Locally repairable codes (LRCs) have gained significant interest for the design of large distributed storage systems as they allow a small number of erased nodes to be recovered by accessing only a few others. Several works have thus been carried out to understand the optimal rate-distance tradeoff, but only recently the size of the alphabet has been taken into account. In this paper, a novel definition of locality is proposed to keep track of the precise number of nodes required for a local repair when the repair sets do not yield MDS codes. Then, a new alphabet-dependent bound is derived, which applies both to the new definition and the initial definition of locality. The new bound is based on consecutive residual codes and intrinsically uses the Griesmer bound. A special case of the bound yields both the extension of the Cadambe-Mazumdar bound and the Singleton-type bound for codes with locality (r, delta), implying that the new bound is at least as good as these bounds. Furthermore, an upper bound on the asymptotic rate-distance tradeoff of LRCs is derived, and yields the tightest known upper bound for large relative minimum distances. Achievability results are also provided by deriving the locality of the family of Simplex codes together with a few examples of optimal codes.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Locally repairable codes (LRCs), upper bound, Griesmer bound
National Category
Computational Mathematics Discrete Mathematics Algebra and Logic Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Mathematics/Applied Mathematics
Identifiers
urn:nbn:se:mdh:diva-46332 (URN)10.1109/TIT.2019.2911595 (DOI)000487041200008 ()2-s2.0-85077357211 (Scopus ID)
Available from: 2019-12-13 Created: 2019-12-13 Last updated: 2025-10-10Bibliographically approved
Grezet, M., Westerback, T., Freij-Hollanti, R. & Hollanti, C. (2019). Uniform Minors in Maximally Recoverable Codes. IEEE Communications Letters, 23(8), 1297-1300
Open this publication in new window or tab >>Uniform Minors in Maximally Recoverable Codes
2019 (English)In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 23, no 8, p. 1297-1300Article in journal (Refereed) Published
Abstract [en]

In this letter, locally recoverable codes with maximal recoverability are studied with a focus on identifying the MDS codes resulting from puncturing and shortening. By using matroid theory and the relation between MDS codes and uniform minors, the list of all the possible uniform minors is derived. This list is used to improve the known non-asymptotic lower bound on the required field size of a maximally recoverable code.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Distributed storage, locally repairable codes, maximally recoverable codes, uniform minors, field size
National Category
Educational Sciences
Identifiers
urn:nbn:se:mdh:diva-45093 (URN)10.1109/LCOMM.2019.2921540 (DOI)000480653100004 ()
Available from: 2019-08-28 Created: 2019-08-28 Last updated: 2025-10-10Bibliographically approved
Westerback, T., Britz, T. & Shiromoto, K. (2015). Demi-matroids from codes over finite Frobenius rings. Designs, Codes and Cryptography, 75(1), 97-107
Open this publication in new window or tab >>Demi-matroids from codes over finite Frobenius rings
2015 (English)In: Designs, Codes and Cryptography, ISSN 0925-1022, E-ISSN 1573-7586, Vol. 75, no 1, p. 97-107Article in journal (Refereed) Published
National Category
Other Mathematics Discrete Mathematics
Research subject
Mathematics/Applied Mathematics
Identifiers
urn:nbn:se:mdh:diva-50958 (URN)10.1007/s10623-013-9895-3 (DOI)000351158100008 ()2-s2.0-84925290595 (Scopus ID)
Available from: 2020-09-29 Created: 2020-09-29 Last updated: 2025-10-10Bibliographically approved
Organisations

Search in DiVA

Show all publications