Kai Morgan Kjølerbakken

• Kjølerbakken, Kai Morgan; Miloch, Wojciech Jacek & Røed, Ketil (2023). Sheath formation time for spherical Langmuir probes. Journal of Plasma Physics. ISSN 0022-3778. 89(1). doi: 10.1017/S0022377822001027. Full text in Research Archive Show summary

  The formation time of the surrounding sheath of Langmuir probes in an ionospheric plasma has been studied to better understand the constraints this puts on the sampling frequency of a probe. A fully kinetic three-dimensional particle-in-cell model is used to simulate the temporal effects in the electron saturation region as the sheath forms. The stability of the probe current and the stability of the ion and electron density in the vicinity of the probe have been used to evaluate when the sheath was formed. Simulated results were compared with theoretical models and are in good agreement with the theoretical results. This shows that theoretical models can be used as guidance to estimate the formation time and to determine the sampling rate for a swept bias Langmuir system. Our results also show that the formation time is less affected by the plasma temperature and bias voltage as we move into the thick sheath regime, and will instead be determined by the plasma density. The presented results also show that applying a step function to the probe could be used to characterise ions species composition, or to estimate the ion density.

• Kjølerbakken, Kai Morgan; Miloch, Wojciech Jacek; Martinsen, Ørjan Grøttem; Pabst, Oliver & Røed, Ketil (2022). Numerical Study of Non-Linear Effects for a Swept Bias Langmuir Probe. IEEE Transactions on Plasma Science. ISSN 0093-3813. 50(5), p. 1237–1245. doi: 10.1109/TPS.2022.3164220. Full text in Research Archive Show summary

  We present a numerical study disclosing non-linear effects and hysteresis loops for a swept bias Langmuir probe. A full kinetic particle in cell (PIC) model has been used to study the temporal sheath effects and the probe current. Langmuir "close to steady state" condition is required to characterize the plasma. However, during operations above frequencies normally used, capacitive and non-linear resistive effects are being unveiled. We demonstrate how ion and electron density and temperature change properties of the probe-plasma system. We also show that a swept Langmuir probe exhibits essential properties described as the "fingerprint of memristors" and how a Langmuir probe can be identified as a transversal memristor. Understanding non-linear processes might enable new ways to operate Langmuir probes with higher sampling rates and better accuracy.

• Kjølerbakken, Kai Morgan; Miloch, Wojciech Jacek & Røed, Ketil (2021). The influence of probe spacing and probe bias in a double Langmuir probe setup. AIP Advances. 11. doi: 10.1063/5.0058540. Full text in Research Archive Show summary

  Multi-needle Langmuir probes are mounted on satellites and sounding rockets for high-frequency characterization of plasma in the ionosphere. Mounted on a spacecraft, the recorded probe current often differs from expected results. In this paper, we perform a numerical study using a particle in cell model to see how the spacing between the individual probes used in a multi-needle setup influences the measured current. We also study how the applied probe bias voltage can contribute to deviations. In our study, we use realistic electron temperatures and electron densities for the relevant part of the ionosphere. However, the results should be generally applicable and valid for other space environments as well as for laboratory Langmuir probe applications. From our study, we can see that when the distance is short, less than two Debye lengths, the current is highly affected, and we can see deviations of more than 60% compared to a single probe setup.

• Hafizovic, Ines; Nilsen, Carl-Inge Colombo; Kjølerbakken, Kai Morgan & Jahr, Vibeke (2012). Design and implementation of a MEMS microphone array system for real-time speech acquisition. Applied Acoustics. ISSN 0003-682X. 73(2), p. 132–143. doi: 10.1016/j.apacoust.2011.07.009. Full text in Research Archive
• Hafizovic, Ines; Nilsen, Carl-Inge Colombo & Kjølerbakken, Kai Morgan (2010). Acoustic Tracking of Aircraft Using a Circular Microphone Array Sensor. In Mooradd, David (Eds.), Proceedings of the 2010 IEEE International Symposium on Phased Array Systems and Technology. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781424451289. Full text in Research Archive
• Holm, S; Brungot, John; Ronnekleiv, A; Hoff, Lars; Jahr, Vibeke & Kjølerbakken, Kai Morgan (2007). Acoustic passive integrated transponders for fish tagging and identification. Aquacultural Engineering. ISSN 0144-8609. 36. Full text in Research Archive Show summary

  The results indicate that it is possible to develop a low-cost system for underwater identification of fish suitable for a high automation level. This could open up for improvements of logistics in for instance the fish fanning industry. (c) 2006 Elsevier B.V. All rights reserved.

• Hafizovic, Ines; Kjølerbakken, Morgan & Jahr, Vibeke (2007). System configuration for high quality audio capturing in a large microphone array. In Reiss, Josh (Eds.), Proceedings of the 31st AES International Conference: New Directions in High Resolution Audio. Audio Engineering Society. ISSN 9781604239805. Full text in Research Archive
• Holm, S; Brungot, J; Rønnekleiv, Arne; Hoff, L; Jahr, V & Kjolerbakken, KM [Show all 7 contributors for this article] (2007). Acoustic passive integrated transponders for fish tagging and identification. Aquacultural Engineering. ISSN 0144-8609. 36. doi: 10.1016/j.aquaeng.2006.09.003. Full text in Research Archive
• Hoff, Lars; Rønnekleiv, Arne; Brungot, John; Wang, Dag; Bernstein, Ralph & Jahr, Vibeke [Show all 8 contributors for this article] (2006). Design of micromachined resonators for fish identification. IEEE International Ultrasonics Symposium Proceedings. ISSN 1051-0117. X(XX), p. 641–644. Full text in Research Archive
• Rønnekleiv, Arne; Brungot, John; Wang, Dag; Bernstein, Ralph; Jahr, Vibeke & Kjølerbakken, Kai Morgan [Show all 7 contributors for this article] (2005). Design of Micromachined Resonators for Fish Identification. IEEE International Ultrasonics Symposium Proceedings. ISSN 1051-0117. Full text in Research Archive

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• Misra, Sanjay; Kjølerbakken, Kai Morgan & Braarud, Per Øivind (2026). International Conference on Human Centric Artificial Intelligence (ICHCAI): First International Conference, ICHCAI 2026. IEEE (Institute of Electrical and Electronics Engineers). ISBN 9798331551186. doi: 10.1109/ICHCAI70183.2026. Full text in Research Archive Show summary

  The 1st International Conference on Human Centric Artificial Intelligence (ICHCAI 2026) brings together researchers, practitioners, and industry leaders to explore the integration of human-centered principles into AI systems. Focusing on trust, ethics, safety, and usability, ICHCAI 2026 addresses challenges in high-risk domains such as nuclear energy, healthcare, critical infrastructure, and digital transformation. This interdisciplinary conference promotes innovation in human-AI collaboration, explainable AI, organizational resilience, and responsible AI governance. We welcome original research, case studies, and policy insights from academia, industry, and government. ICHAI 2026 is sponsored by The Norwegian Research Council and technically supported by IEEE Norway Section and IEEE Computer Soceity Norway Chapter.

• Misra, Sanjay; Kvalvik, Petter; Kjølerbakken, Kai Morgan & Jørgensen, Per-Arne (2026). 2nd International Conference on Digital Sovereignty: Proceedings of ICDS 2025. Springer Nature Switzerland. ISBN 9783032215239. doi: 10.1007/978-3-032-21524-6. Full text in Research Archive Show summary

  This book provides a comprehensive exploration of digital sovereignty, addressing its intersection with autonomy, privacy, security, and trust within complex digital infrastructures. By examining topics such as data governance in cloud technologies, the role of foreign tech giants, and the management of critical systems like healthcare, energy, and transportation, it tackles urgent challenges surrounding control, transparency, and accountability in an increasingly digital world. Join experts from industry, academia, and the public sector as they explore the multifaceted aspects of digital sovereignty and its implications for infrastructure, governance, and innovation. The chapters cover secure data spaces, autonomous cloud services, distributed identity systems, and interoperable digital infrastructures, particularly in the public sector. With growing geopolitical tensions and reliance on non-European tech providers, Europe is stepping up, pushing for digital sovereignty through bold regulation and forward-thinking innovation. This timely book offers cutting-edge insights from interdisciplinary fields, including AI, IoT, cybersecurity, governance, and geopolitics. It is essential for scholars, policymakers, and technologists seeking to navigate the complexities of digital trust, ethical autonomy, and societal resilience in the digital age. As digital infrastructure and data become central to societal function, the question of who controls them has never been more critical.

• Misra, Sanjay; Chockalingam, Sabarathinam; Kvalvik, Petter; Kjølerbakken, Kai Morgan; Braarud, Per Øivind & Jørgensen, Per-Arne (2026). Digital Sovereignty and Human-Centric AI - Book Series - Routledge & CRC Press. Routledge. Full text in Research Archive Show summary

  This series is established to position European researchers, particularly in Norway, at the forefront of scholarship and academic publishing on Human-Centric AI and Digital Sovereignty. Addressing one of the defining challenges of our time, it explores how AI can be developed and governed to uphold human dignity, democratic values, and digital sovereignty. Through interdisciplinary research and dialogue, the series advances ethical, transparent, and accountable AI while charting pathways toward a trustworthy, inclusive, and resilient digital future.

• Misra, Sanjay; Kvalvik, Petter; Gran, Bjørn Axel; Kjølerbakken, Kai Morgan; Omerovic, Aida & Noori, Nadia Saad (2026). Artificial Intelligence in Context of Digital Sovereignty - 1st Editio. Routledge. ISBN 9781032945507. 408 p. Full text in Research Archive Show summary

  In a world increasingly shaped by technology, digital sovereignty is a critical need for nations and organizations to preserve their autonomy. It is more than just control over data and infrastructure; it's about safeguarding values, privacy, and ethics in an era of AI. This concept empowers entities to reduce dependency on foreign tech, ensuring that their digital future reflects their unique priorities and needs. It offers crucial insights for those navigating the shifting technological and ge

• Misra, Sanjay; Kvalvik, Petter; Gran, Bjørn Axel; Kjølerbakken, Kai Morgan; Omerovic, Aida & Noori, Nadia Saad (2026). Artificial Intelligence in Context of Digital Sovereignty. Routledge. ISBN 9781003581581. 408 p. doi: 10.1201/9781003581581. Full text in Research Archive Show summary

  In a world increasingly shaped by technology, digital sovereignty is a critical need for nations and organizations to preserve their autonomy. It is more than just control over data and infrastructure; it's about safeguarding values, privacy, and ethics in an era of AI. This concept empowers entities to reduce dependency on foreign tech, ensuring that their digital future reflects their unique priorities and needs. It offers crucial insights for those navigating the shifting technological and geopolitical landscape, providing both thought-provoking theory and practical strategies for achieving digital independence. The book offers a roadmap for navigating the complexities of the adoption of AI, focusing on privacy, security, and the importance of aligning AI with local values. It's a timely guide for anyone invested in the future of technology and geopolitics. This book is essential reading for policymakers, academics, tech practitioners, and anyone concerned with the intersection of AI, digital sovereignty, and cybersecurity. Key Features: Discusses the improvement of digital sovereignty with reference to AI to meet legal and technological barriers/challenges. Gives the current status of development of Digital sovereignty and its realization. Discusses the improvement of policies regarding digital sovereignty. Covers a broad spectrum of topics that are related to cyber sovereignty, data sovereignty, technological sovereignty, role of AI, industrial applications, data center sovereignty, industrial data space, and others. Functions as a platform for experts in many fields to share their novel insights and showcase the multidisciplinary nature of the field.

• Misra, Sanjay; Kvalvik, Petter; Kjølerbakken, Kai Morgan & Jørgensen, Per-Arne (2025). Empowering Digital Sovereignty: Balancing Privacy and Global Connectivity. IGI Global. ISBN 9798369391372. 464 p. Full text in Research Archive
• Ogul, Hasan; Aamodt, Jonas Moræus; Misra, Sanjay & Kjølerbakken, Kai Morgan (2024). 2024 4th International Conference on Applied Artificial Intelligence (ICAPAI). IEEE (Institute of Electrical and Electronics Engineers). ISBN 9798350349764. 300 p. Full text in Research Archive

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• Misra, Sanjay; Kvalvik, Petter; Kjølerbakken, Kai Morgan & Damaševičius, R. (2025). Preface on Special Issue for International Conference on Digital Sovereignty. Procedia Computer Science. 254, p. 1–9. doi: 10.1016/j.procs.2025.02.058. Full text in Research Archive
• Brungot, John; Holm, Sverre; Hoff, Lars; Rønnekleiv, Arne; Kjølerbakken, Kai Morgan & Jahr, Vibeke (2004). VivID – patentert metode for merking og identifisering av fisk i vann. Full text in Research Archive
• Lindem, Torfinn; Balk, Helge; Vibeke, J. & Kjølerbakken, K. M. (2002). Measurements of acoustic sound fields in a shallow river. Full text in Research Archive Show summary

  From earlier experiments, we have seen indications that the sound field from a horizontally aligned transducer in shallow water can differ from the expected field. If this is the case, this phenomenon can have an impact on the measured target strength from fish and on sample volume. Hence, it has been important to verify this by controlled experiments. We have measured the sound field produced by a Simrad ES120-4, 120kHz, 4x10 deg. split beam transducer in a shallow river. These measurements were made with a Reason hydrophone. Reflections from the bottom and surface made modifications to the transmitted pulse. In some positions they could even form separate pulses. These pulses were sufficiently separated in time to produce phantom echoes. Results from this experiment will be presented.

• Kjølerbakken, Kai Morgan (2022). Computational Study of Langmuir Probe Properties in Ionospheric Plasma. Universitetet i Oslo. Full text in Research Archive
• Kjølerbakken, Morgan & Vallejo, Islen (2015). Teknisk løsning for nasjonalt beregningsverktøy. Dataflyt, systemdesign og krav til infrastruktur. NILU. ISSN 9788242527714. Full text in Research Archive Show summary

  Rapporten beskriver dataflyt, systemdesign og krav til infrastruktur for et system som modellerer og beregner luftkvalitet. Rapporten inneholder også beskrivelse av brukergrensesnittet i en webløsning.

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