A database for publications published by researchers and students at SimulaMet.
Research area
Publication type
- All (754)
- Journal articles (211)
- Books (7)
- Edited books (1)
- Proceedings, refereed (235)
- Book chapters (6)
- Talks, keynote (17)
- PhD theses (1)
- Proceedings, non-refereed (18)
- Posters (11)
- Technical reports (11)
- Manuals (1)
- Talks, invited (159)
- Talks, contributed (18) Remove Talks, contributed <span class="counter">(18)</span> filter
- Public outreach (46)
- Miscellaneous (12)
Talks, contributed
NorNet – A Linux- and Open-Source-Software-based International Platform for Networking Research
In Virtual. Melbourne, Australia: Linux Conference Australia, 2022.Status: Published
NorNet – A Linux- and Open-Source-Software-based International Platform for Networking Research
The NorNet testbed (https://www.nntb.no) is an Internet testbed platform for research on multi-homed systems. The particular property of multi-homed systems is to be connected to multiple Internet Service Providers (ISP) simultaneously. Its initial purpose is of course to still provide connectivity in case of ISP/network failures. But does it really work that well, also with current protocols and applications? And redundancy does not come for free. A user connected to multiple ISPs will also receive multiple Internet bills each month. So, is there a possibility to make further use of multi-homing in the usual case where nothing goes wrong? Obviously, there are a lot of interesting research questions, which need to be examined in realistic Internet setups! Therefore, we are building up the NorNet open Internet testbed platform as a Linux- and Open-Source-software-based infrastructure, which currently spreads over multiple sites in different countries.
NorNet makes extensive use of advanced Linux features like Kernel-based Virtualisation (KVM), Linux Containers (LXC), BTRFS file system features, IP routing rules, Stream Control Transmission Protocol (SCTP), Multi-Path TCP (MPTCP), and many more. The goal of this talk is therefore to present an overview of the testbed, its underlying Linux features, and how they are combined to provide the multi-homing features to the various testbed users. This particularly includes an overview of how to make use of multi-path transport with MPTCP – based on the Linux MPTCP implementation – in multi-homed environments. The idea is to provide guidelines for also utilising multi-homing features in own projects.
| Afilliation | Communication Systems |
| Project(s) | NorNet, The Center for Resilient Networks and Applications, Simula Metropolitan Center for Digital Engineering, Simula Metropolitan Center for Digital Engineering, 5G-VINNI: 5G Verticals INNovation Infrastructure |
| Publication Type | Talks, contributed |
| Year of Publication | 2022 |
| Location of Talk | Virtual |
| Publisher | Linux Conference Australia |
| Place Published | Melbourne, Australia |
| Keywords | Linux, Multi-Homing, Multi-Path Transport, NorNet, Open Source, Testbed |
| URL | https://lca2022.linux.org.au/schedule/presentation/52/ |
Talks, contributed
Tracing Dynamic Networks through Constrained Parafac2 Decomposition
In Virtual Conference. SIAM Conference on Applied Linear Algebra (LA21), 2021.Status: Published
Tracing Dynamic Networks through Constrained Parafac2 Decomposition
Time-evolving data analysis is crucial for understanding complex systems such as the brain. Methods that assume static networks have successfully recovered spatial networks of connectivity from neuroimaging data. Still, discovering both underlying networks and their evolution is a challenging task.
To capture temporal evolution of connectivity networks, we arrange dynamic data as a tensor and use a tensor factorization method called PARAFAC2. PARAFAC2 deciphers the hidden structure of dynamic networks and yields unique and interpretable components. Preliminary results using PARAFAC2 in neuroimaging data analysis are promising. However, the constant cross-product constraint on the time-evolving mode hinders the use of additional constraints or regularization (e.g. spatial smoothness) on this mode. Currently, the only way to regularize the time-evolving mode of a PARAFAC2 model is with a flexible coupling approach, which finds the solution through regularized least-squares subproblems. Instead, we use an alternating direction method of multipliers (ADMM) based approach to widen the possible regularization penalties to any proximable function.
Our numerical experiments demonstrate that the proposed ADMM-based algorithmic approach for PARAFAC2 can accurately recover the underlying evolving components, is flexible in terms of imposing constraints and also computationally efficient.
| Afilliation | Machine Learning |
| Project(s) | Department of Machine Intelligence, TrACEr: Time-Aware ConstrainEd Multimodal Data Fusion |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | Virtual Conference |
| Publisher | SIAM Conference on Applied Linear Algebra (LA21) |
A Flexible Optimization Framework for Regularized Matrix-Tensor Factorizations with Linear Couplings
In Asilomar Conference on Signals, Systems, and Computers, 2021.Status: Published
A Flexible Optimization Framework for Regularized Matrix-Tensor Factorizations with Linear Couplings
An effective way of jointly analyzing data from multiple sources is through coupled matrix and tensor factorizations (CMTF). Different characteristics of datasets from multiple sources require to employ various regularizations, constraints, loss functions and different types of coupling structures between datasets. While existing algorithmic approaches for CMTF can incorporate constraints, linear couplings and different loss functions, none of them has been shown to achieve the flexibility to incorporate all. We propose a flexible algorithmic framework for coupled matrix and tensor factorizations, which utilizes Alternating Optimization (AO) and the Alternating Direction Method of Multipliers (ADMM). The framework facilitates the use of a variety of constraints, loss functions and couplings with linear transformations. Numerical experiments on simulated datasets and real data from chemometrics and hyperspectral super-resolution demonstrate that the proposed approach is accurate, flexible and computationally efficient with comparable or better performance than available CMTF algorithms.
While we focus on CANDECOMP/PARAFAC (CP) –based CMTF models, we will also briefly discuss the use of an AO-ADMM based algorithmic approach for fitting a PARAFAC2 model. We demonstrate that the proposed algorithmic approach enables imposing constraints in all modes, which has been a challenge using the traditional alternating least squares-based algorithm used for PARAFAC2.
| Afilliation | Machine Learning |
| Project(s) | Department of Machine Intelligence, TrACEr: Time-Aware ConstrainEd Multimodal Data Fusion |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | Asilomar Conference on Signals, Systems, and Computers |
| Type of Talk | Invited Session Talk |
Update on SBD (RFC 8382)
In IETF 112. https://datatracker.ietf.org/meeting/112/proceedings: IETF, 2021.Status: Published
Update on SBD (RFC 8382)
Comparative evaluation of RFC 8382, comparing vanilla RFC 8382, RFC 8382 stats with dynamic online clustering, offline wavelet filtered cross-correlation, online adaption of the wavelet filtered cross-correlation. Concludes with recommendations for future work.
| Afilliation | Communication Systems |
| Project(s) | Department of Mobile Systems and Analytics |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | IETF 112 |
| Publisher | IETF |
| Place Published | https://datatracker.ietf.org/meeting/112/proceedings |
| Type of Talk | Talk to the RMCAT working group |
| URL | https://datatracker.ietf.org/meeting/112/materials/slides-112-rmcat-upda... |
Generalized Low-Rank Models for Phenotyping Cervical Cancer Risk Groups using Medical Questionnaires.
In Stavanger, Norway, 2021.Status: Published
Generalized Low-Rank Models for Phenotyping Cervical Cancer Risk Groups using Medical Questionnaires.
| Afilliation | Machine Learning |
| Project(s) | Department of Machine Intelligence, DeCipher |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | Stavanger, Norway |
Demonstration of P4-Based In-Band Telemetry for OSM-Orchestrated 4G/5G Testbeds
In Virtual, 2021.Status: Published
Demonstration of P4-Based In-Band Telemetry for OSM-Orchestrated 4G/5G Testbeds
The SimulaMet OpenAirInterface VNF provides an OpenAirInterface-based Enhanced Packet Core (EPC), with separate VDUs for HSS, MME, SPGW-C and SPGW-U. To allow for advanced in-band telemetry, we have extended this VNF to add switches with Programming Protocol-independent Packet Processors (P4) to all relevant virtual links inside the EPC. P4 allows full programability of the packet forwarding behaviour, and especially allows to extend packets with additional information for in-band telemetry. This information can be read by other P4 instances to allow for fine-granular performance data collection. In this presentation and live demonstration, we would like show the solutions chosen to efficiently use OSM for handling our extended EPC, and in particular we would like to highlight the possibilities to perform P4-based in-band telemetry to evaluate the performance of the mobile network. Finally, we would also like to show the audience a live demo of our testbed setup with telemetry collection.
| Afilliation | Communication Systems |
| Project(s) | 5G-VINNI: 5G Verticals INNovation Infrastructure , NorNet, The Center for Resilient Networks and Applications, Simula Metropolitan Center for Digital Engineering, Simula Metropolitan Center for Digital Engineering |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | Virtual |
| Type of Talk | Demo presentation |
| Keywords | 5G, In-Band Telemetry, Network Function Virtualisation, Open Source MANO, OpenAirInterface, P4 |
A new linearly implicit energy-preserving exponential method for conservative or dissipative systems.
In In Manifolds and Geometric Integration Colloquia, Norway., 2021.Status: Published
A new linearly implicit energy-preserving exponential method for conservative or dissipative systems.
In this work, we propose a linearly implicit exponential integrator that preserves the invariant or the Lyapunov functions for the conservative or dissipative systems by combining the idea of exponential integrators and discrete gradient methods. Numerical simulations are shown to confirm the conservative properties of the methods, and to demonstrate the efficiency of the methods when compared to other fully implicit schemes.
| Afilliation | Machine Learning |
| Project(s) | Department of Machine Intelligence |
| Publication Type | Talks, contributed |
| Year of Publication | 2021 |
| Location of Talk | In Manifolds and Geometric Integration Colloquia, Norway. |
Talks, contributed
Easily Setting up 4G/5G Testbeds with OpenAirInterface using OSM
In OSM Hackfest, Madrid/Spain. Madrid/Spain: ETSI, 2020.Status: Published
Easily Setting up 4G/5G Testbeds with OpenAirInterface using OSM
Setting up 4G/5G testbeds can be a highly complicated and error-prone task. In this presentation, we introduce our Open Source VNF and tool-chain for an OpenAirInterface-based EPC to be deployed with the OSM framework. Using our VNF and tool-chain as basis, it will be easily possible to create own testbeds, customise them and extend them with further functionalities.
| Afilliation | Communication Systems |
| Project(s) | 5G-VINNI: 5G Verticals INNovation Infrastructure , NorNet, Simula Metropolitan Center for Digital Engineering, The Center for Resilient Networks and Applications |
| Publication Type | Talks, contributed |
| Year of Publication | 2020 |
| Location of Talk | OSM Hackfest, Madrid/Spain |
| Publisher | ETSI |
| Place Published | Madrid/Spain |
| Keywords | 5G, Evolved Packet Core, Network Function Virtualisation, Open Source MANO, OpenAirInterface |
| URL | https://osm-download.etsi.org/ftp/osm-7.0-seven/MR8-hackfest/Ecosystem-D... |
Utvikling og teknologiske veivalg i en krisesituasjon
In Åpent seminar om smittesporing, Fornebu, Norway, 2020.Status: Published
Utvikling og teknologiske veivalg i en krisesituasjon
| Afilliation | Communication Systems |
| Project(s) | The Center for Resilient Networks and Applications |
| Publication Type | Talks, contributed |
| Year of Publication | 2020 |
| Location of Talk | Åpent seminar om smittesporing, Fornebu, Norway |
Talks, contributed
Smart cities for a Sustainable Energy Future- From design to practice
In Technical University of Berlin, Germany, 2019.Status: Published
Smart cities for a Sustainable Energy Future- From design to practice
| Afilliation | Communication Systems |
| Project(s) | Simula Metropolitan Center for Digital Engineering, The Center for Resilient Networks and Applications |
| Publication Type | Talks, contributed |
| Year of Publication | 2019 |
| Location of Talk | Technical University of Berlin, Germany |
| Type of Talk | 2019 LUCS PACE SCiSEF Summer School: Introduction and Overview |