A database for publications published by researchers and students at SimulaMet.
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- Journal articles (282) Remove Journal articles <span class="counter">(282)</span> filter
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- Proceedings, refereed (309)
- Book chapters (13)
- Talks, keynote (21)
- PhD theses (9)
- Proceedings, non-refereed (19)
- Posters (15)
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- Talks, invited (182)
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- Miscellaneous (21)
Journal articles
A comprehensive analysis of classification methods in gastrointestinal endoscopy imaging
Medical Image Analysis 70 (2021): 102007.Status: Published
A comprehensive analysis of classification methods in gastrointestinal endoscopy imaging
Gastrointestinal endoscopy has been an active field of research motivated by the large number of highly lethal GI cancers. Early GI cancer precursors are often missed during the endoscopic surveillance. The high missed rate of such abnormalities during endoscopy is thus a critical bottleneck. Lack of attentiveness due to tiring procedures, and requirement of training are few contributing factors. An automatic GI disease classification system can help reduce such risks by flagging suspicious frames and lesions. GI endoscopy consists of several multi-organ surveillance, therefore, there is need to develop methods that can generalize to various endoscopic findings. In this realm, we present a comprehensive analysis of the Medico GI challenges: Medical Multimedia Task at MediaEval 2017, Medico Multimedia Task at MediaEval 2018, and BioMedia ACM MM Grand Challenge 2019. These challenges are initiative to set-up a benchmark for different computer vision methods applied to the multi-class endoscopic images and promote to build new approaches that could reliably be used in clinics. We report the performance of 21 participating teams over a period of three consecutive years and provide a detailed analysis of the methods used by the participants, highlighting the challenges and shortcomings of the current approaches and dissect their credibility for the use in clinical settings. Our analysis revealed that the participants achieved an improvement on maximum Mathew correlation coefficient (MCC) from 82.68% in 2017 to 93.98% in 2018 and 95.20% in 2019 challenges, and a significant increase in computational speed over consecutive years.
Afilliation | Machine Learning |
Project(s) | Department of Holistic Systems |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | Medical Image Analysis |
Volume | 70 |
Pagination | 102007 |
Publisher | Elsevier |
Keywords | Artificial intelligence, BioMedia 2019 Grand Challenge, Computer-aided detection and diagnosis, Gastrointestinal endoscopy challenges, Medical imaging, Medico Task 2017, Medico Task 2018 |
DOI | 10.1016/j.media.2021.102007 |
A Comprehensive Study on Colorectal Polyp Segmentation with ResUNet++, Conditional Random Field and Test-Time Augmentation
IEEE Journal of Biomedical and Health Informatics 25, no. 6 (2021): 2029-2040.Status: Published
A Comprehensive Study on Colorectal Polyp Segmentation with ResUNet++, Conditional Random Field and Test-Time Augmentation
Colonoscopy is considered the gold standard for detection of colorectal cancer and its precursors. Existing examination methods are, however, hampered by high overall miss-rate, and many abnormalities are left undetected. Computer-Aided Diagnosis systems based on advanced machine learning algorithms are touted as a game-changer that can identify regions in the colon overlooked by the physicians during endoscopic examinations, and help detect and characterize lesions. In previous work, we have proposed the ResUNet++ architecture and demonstrated that it produces more efficient results compared with its counterparts U-Net and ResUNet. In this paper, we demonstrate that further improvements to the overall prediction performance of the ResUNet++ architecture can be achieved by using Conditional Random Field (CRF) and Test-Time Augmentation (TTA). We have performed extensive evaluations and validated the improvements using six publicly available datasets: Kvasir-SEG, CVC-ClinicDB, CVC-ColonDB, ETIS-Larib PolypDB, ASU-Mayo Clinic Colonoscopy Video Database, and CVC-VideoClinicDB. Moreover, we compare our proposed architecture and resulting model with other State-of-the-art methods. To explore the generalization capability of ResUNet++ on different publicly available polyp datasets, so that it could be used in a real-world setting, we performed an extensive cross-dataset evaluation. The experimental results show that applying CRF andTTA improves the performance on various polyp segmentation datasets both on the same dataset and cross-dataset. To check the model’s performance on difficult to detect polyps, we selected, with the help of an expert gastroenterologist,196sessile or flat polyps that are less than ten millimeters in size. This additional data has been made available as a subset of Kvasir-SEG. Our approaches showed good results for flat or sessile and smaller polyps, which are known to be one of the major reasons for high polyp miss-rates. This is one of the significant strengths of our work and indicates that our methods should be investigated further for use in clinical practice.
Afilliation | Machine Learning |
Project(s) | Department of Holistic Systems |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | IEEE Journal of Biomedical and Health Informatics |
Volume | 25 |
Issue | 6 |
Pagination | 2029 - 2040 |
Publisher | IEEE |
Keywords | colonoscopy, conditional random field, generalization, Polyp segmentation, ResUNet++, test-time augmentation |
DOI | 10.1109/JBHI.2021.3049304 |
A field experiment on trialsourcing and the effect of contract types on outsourced software development
Information and Software Technology 134 (2021): 106559.Status: Published
A field experiment on trialsourcing and the effect of contract types on outsourced software development
Context: To ensure the success of software projects, it is essential to select skilled developers and to use suitable work contracts. Objective: This study tests two hypotheses: (i) the use of work-sample testing (trialsourcing) improves the selection of skilled software developers; and (ii) the use of contracts based on hourly payment leads to better software project outcomes than fixed-price contracts. Method: Fifty-seven software freelancers with relevant experience and good evaluation scores from previous clients were invited to complete a two-hour long trialsourcing task to qualify for a software development project. Thirty-six developers completed the trialsourcing task with acceptable performance, and, based on a stratified allocation process, were asked to give a proposal based on an hourly payment or a fixed-price contract. Eight hourly payment-based and eight fixed-priced proposals were accepted. The process and product characteristics of the completion of these 16 projects were collected and analysed. Results and Conclusion: Only partial support for our hypotheses was observed. While the use of trialsourcing may have prevented the selection of developers with insufficient skills, the performance on the trialsourcing task of the selected developers did not predict performance on the project. The use of hourly payments led to lower costs than fixed-price contracts, but not to improved processes or products. We plan to follow up these, to us unexpected, results with research on how to design more skill-predictive trialsourcing tasks, and when and why different project contexts give different contract consequences.
Afilliation | Software Engineering |
Project(s) | Department of IT Management |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | Information and Software Technology |
Volume | 134 |
Pagination | 106559 |
Date Published | June 2021 |
Publisher | Elsevier |
A Flexible Optimization Framework for Regularized Matrix-Tensor Factorizations with Linear Couplings
IEEE Journal of Selected Topics in Signal Processing 15, no. 3 (2021): 506-521.Status: Published
A Flexible Optimization Framework for Regularized Matrix-Tensor Factorizations with Linear Couplings
Afilliation | Machine Learning |
Project(s) | TrACEr: Time-Aware ConstrainEd Multimodal Data Fusion, Department of Data Science and Knowledge Discovery |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | IEEE Journal of Selected Topics in Signal Processing |
Volume | 15 |
Issue | 3 |
Pagination | 506 - 521 |
Publisher | IEEE |
DOI | 10.1109/JSTSP.2020.3045848 |
A Multi-Parameter Comprehensive Optimized Algorithm for MPTCP Networks
Electronics 10, no. 16 (2021).Status: Published
A Multi-Parameter Comprehensive Optimized Algorithm for MPTCP Networks
With the increasing deployment of the Multi-Path Transmission Control Protocol (MPTCP) in heterogeneous network setups, there is a need to understand how its performance is affected in practice both by traditional factors such as round-trip time measurements, buffer predictive modelling and by calculating the impact factors of network subflows. Studies have shown that path management and packet scheduling have a large effect on overall performance and required limited resources with different congestion control parameters. Unfortunately, most of the previous studies have focused almost exclusively on the improvement of a single parameter, without a holistic view. To deal with this issue effectively, this paper puts forward a Multi-Parameter Comprehensive Optimized Algorithm (MPCOA), which can find the smaller buffer size and select the appropriate congestion control and path management algorithm on the premise of ensuring larger throughput. Experiments of three scenarios show that MPCOA can save the buffer space and subflow resources, and achieve high throughput. Meanwhile, a set of quantitative improvement results given by MPCOA is convenient for us to evaluate the quality of MPTCP network, and provide reference for our ongoing future work, like for 4G/5G, Internet of Things and Star Link networks.
Afilliation | Communication Systems |
Project(s) | The Center for Resilient Networks and Applications, NorNet, SMIL: SimulaMet Interoperability Lab, Simula Metropolitan Center for Digital Engineering, Simula Metropolitan Center for Digital Engineering, GAIA |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | Electronics |
Volume | 10 |
Issue | 16 |
Date Published | 08/2021 |
Publisher | MDPI |
Place Published | Basel/Switzerland |
ISSN | 2079-9292 |
Keywords | Buffer Size, congestion control, MPCOA, Multi-Path TCP (MPTCP), Path Management |
URL | https://www.mdpi.com/2079-9292/10/16/1942/pdf |
DOI | 10.3390/electronics10161942 |
A Multi-Perspective Study of Internet Performance during the COVID-19 Outbreak
Arxiv (2021).Status: Published
A Multi-Perspective Study of Internet Performance during the COVID-19 Outbreak
Afilliation | Communication Systems |
Project(s) | Simula Metropolitan Center for Digital Engineering, GAIA |
Publication Type | Journal Article |
Year of Publication | 2021 |
Journal | Arxiv |
Publisher | Arxiv |
Place Published | Arrxiv.org |
Keywords | COVID, Internet, network |
DOI | 10.48550/arXiv.2101.05030 |
Journal articles
A Genetic Attack Against Machine Learning Classifiers to Steal Biometric Actigraphy Profiles from Health Related Sensor Data
Journal of Medical Systems 44, no. 10 (2020): 1-11.Status: Published
A Genetic Attack Against Machine Learning Classifiers to Steal Biometric Actigraphy Profiles from Health Related Sensor Data
Afilliation | Machine Learning |
Project(s) | Department of Holistic Systems |
Publication Type | Journal Article |
Year of Publication | 2020 |
Journal | Journal of Medical Systems |
Volume | 44 |
Issue | 10 |
Pagination | 1-11 |
Date Published | Jan-10-2020 |
Publisher | Springer |
ISSN | 0148-5598 |
URL | http://link.springer.com/10.1007/s10916-020-01646-y |
DOI | 10.1007/s10916-020-01646-y |
A Modular Experimentation Methodology for 5G Deployments: The 5GENESIS Approach
Sensors 20 (2020): 6652.Status: Published
A Modular Experimentation Methodology for 5G Deployments: The 5GENESIS Approach
The high heterogeneity of 5G use cases requires the extension of the traditional per-component testing procedures provided by certification organizations, in order to devise and incorporate methodologies that cover the testing requirements from vertical applications and services. In this paper, we introduce an experimentation methodology that is defined in the context of the 5GENESIS project, which aims at enabling both the testing of network components and validation of E2E KPIs. The most important contributions of this methodology are its modularity and flexibility, as well as the open-source software that was developed for its application, which enable lightweight adoption of the methodology in any 5G testbed. We also demonstrate how the methodology can be used, by executing and analyzing different experiments in a 5G Non-Standalone (NSA) deployment at the University of Malaga. The key findings of the paper are an initial 5G performance assessment and KPI analysis and the detection of under-performance issues at the application level. Those findings highlight the need for reliable testing and validation procedures towards a fair benchmarking of generic 5G services and applications.
Afilliation | Communication Systems |
Project(s) | Department of Mobile Systems and Analytics |
Publication Type | Journal Article |
Year of Publication | 2020 |
Journal | Sensors |
Volume | 20 |
Number | 22 |
Pagination | 6652 |
Date Published | 11/2020 |
Publisher | MDPI |
Keywords | 5G, Experimentation, methodology, Testbeds |
URL | https://www.mdpi.com/1424-8220/20/22/6652 |
DOI | 10.3390/s20226652 |
Journal articles
A longitudinal explanatory case study of coordination in a very large development programme: the impact of transitioning from a first- to a second-generation large-scale agile development method
Empirical Software Engineering 28, no. 1 (2023).Status: Published
A longitudinal explanatory case study of coordination in a very large development programme: the impact of transitioning from a first- to a second-generation large-scale agile development method
Large-scale agile development has gained widespread interest in the software industry, but it is a topic with few empirical studies of practice. Development projects at scale introduce a range of new challenges in managing a large number of people and teams, often with high uncertainty about product requirements and technical solutions. The coordination of teams has been identified as one of the main challenges. This study presents a rich longitudinal explanatory case study of a very large software development programme with 10 development teams. We focus on inter-team coordination in two phases: one that applies a first-generation agile development method and another that uses a second-generation one. We identified 27 coordination mechanisms in the first phase, and 14 coordination mechanisms in the second. Based on an analysis of coordination strategies and mechanisms, we develop five propositions on how the transition from a first- to a second-generation method impacts coordination. These propositions have implications for theory and practice.
Afilliation | Software Engineering |
Project(s) | EDOS: Effective Digitalization of Public Sector |
Publication Type | Journal Article |
Year of Publication | 2023 |
Journal | Empirical Software Engineering |
Volume | 28 |
Issue | 1 |
Date Published | Jan-01-2023 |
Publisher | Springer Nature |
ISSN | 1382-3256 |
Keywords | coordination mechanisms, inter-team coordination, large-scale agile development, multiteam systems, software development process, Software Engineering |
URL | https://rdcu.be/c3FQ4 |
DOI | 10.1007/s10664-022-10230-6 |
A multi-center polyp detection and segmentation dataset for generalisability assessment
Nature Scientific Data 10 (2023).Status: Published
A multi-center polyp detection and segmentation dataset for generalisability assessment
Afilliation | Machine Learning |
Project(s) | Department of Holistic Systems |
Publication Type | Journal Article |
Year of Publication | 2023 |
Journal | Nature Scientific Data |
Volume | 10 |
Publisher | Nature |
URL | https://doi.org/10.1038/s41597-023-01981-y |
DOI | 10.1038/s41597-023-01981-y |