FFI Publikasjoner: Recent submissions
Now showing items 101-120 of 2966
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Optical turbulence on 1-km horizontal path with short and medium IR Gaussian laser beams
(2023-10-19)We have investigated effects of optical turbulence on laser beams with wavelengths of λ = 1064 nm and 2036 nm. The two laser beams (one diode and one thulium fiber laser) were expanded to 7 cm diameter through a common ... -
Spectral reflectance properties of sand layers covering an underlying target: experimental measurements and mathematical modelling
(2023-10-23)Adapting to natural backgrounds is important, yet very difficult, to achieve effective camouflage. One interesting aspect is the optical depth of biomaterials as a function of both geographical region, in which the ... -
LybinTCPServer 7.0.5 - interface description
(2023-12-18)LYBIN is a robust, user friendly and fast acoustic ray-trace simulator. A broad set of parameters is used to accurately calculate the probability of detecting objects in a given area under water with the use of sonar ... -
War and the Willingness to Resist and Fight in Ukraine
(2023-12-05)This study explores the effects of Russia's use of military force on the Ukrainian willingness to fight and resist. We find assumptions from the theoretical literature on the willingness to fight of limited relevance. ... -
Strategisk samarbeid i Forsvarsmateriell – hva kreves for å lykkes?
(2024-02-22)Strategisk samarbeid har fått stor oppmerksomhet i løpet av de siste langtidsplanperiodene. I inneværende langtidsplan heter det at Forsvarsmateriell (FMA) skal intensivere arbeidet med strategisk samarbeid med ... -
Oppvarming ved laserstråling – første forsøk med enkle konstruksjonsmaterialer
(2024-02-15)Prosjektet «Laservåpen og beskyttelse» innenfor forskningsprogrammet «Luftvern, ubemannede luftsystemer og laser» går ut på å utvikle høyeffektlasere som mottiltak mot innkommende prosjektiler, droner og liknende. Denne ... -
LYBIN 7.0 – user manual
(2024-01-05)The acoustic ray trace model LYBIN is a well-established and frequently used sonar prediction model owned by the Norwegian Defence Materiel Agency (NDMA). The model is used aboard navy vessels as well as in training ... -
RIMFAX Ground Penetrating Radar Reveals Dielectric Permittivity and Rock Density of Shallow Martian Subsurface
(2023-06-02)The Mars 2020 Perseverance Rover is equipped with the RIMFAX ground penetrating radar instrument which has been continuously surveying the shallow subsurface during the rover's journey. Within the first 379 mission ... -
Radar Attenuation in the Shallow Martian Subsurface: RIMFAX Time-Frequency Analysis and Constant-Q Characterization Over Jezero Crater Floor
(2023-04-16)Attenuation of radar waves in the subsurface can be quantified with a constant-Q approximation through time-frequency analysis. We implement the centroid frequency-shift method and study Radar Imager for Mars' Subsurface ... -
The impacts of scene stability and acoustic backscatter coherence on automated seabed change detection
(2023-09)Practical implementation of long-term seabed monitoring for civilian and military activities requires automated tools for detecting temporal seabed changes, such as for detection of new trawling activities or mine-like ... -
Challenges of Automated Change Detection in Repeat-pass Synthetic Aperture Sonar Imagery
(2023)Change detection extracts regions of interest as temporal differences by imaging a scene before and after changes may have occurred. We denote the initial image as the reference and the more recent as the current image. ... -
A wavelet schrinkage approach to detect candidate point scatterers in synthetic aperture sonar images for resolution estimation
(2023)Autonomous Underwater Vehicles (AUVs) that are equipped with side-looking synthetic aperture sonar (SAS) have become a popular asset for efficient high resolution imaging and mapping of the seafloor. There are situations ... -
Comparison of model selection techniques for seafloor scattering statistics
(2023)Acoustic measurements of seafloor backscattering are a source of unwanted sound in seafloor object detection1–3, but also provide a rich set of information regarding the seafloor properties and structure4–7. The intensity ... -
Uncertainty quantification with deep learning through variational inference with applications to synthetic aperture sonar
(2023)Deep learning (DL) has gained popularity in applications and research within the active sonar community both in academic and commercial settings due to the ability of such models to learn complex non-linear relationships ... -
A Study on the Effect of Commonly Used Data Augmentation Techniques on Sonar Image Artifact Detection Using Deep Neural Networks
(2023-10-20)This paper presents an empirical study that evaluates the impact of different types of augmentations on the performance of Deep Learning (DL) models for detecting imaging artifacts in Synthetic Aperture Sonar (SAS) imagery. ... -
Space-Based AIS with a Norwegian Small-Satellite Constellation
(2023)Over the past couple of decades, small satellites have evolved from demonstrators to operational assets to enable low-cost space access for government services and commercial service providers. The Norwegian AIS constellation ... -
Bacterial Brain Abscesses Expand Despite Effective AntibioticTreatment: A Process Powered by Osmosis Due to NeutrophilCell Death
(2023-12-12)BACKGROUND AND OBJECTIVES: A bacterial brain abscess is an emergency and should be drained of pus within 24 hours of diagnosis, as recently recommended. In this cross-sectional study, we investigated whether delaying ... -
War in Europe, but Still Low Tension in the High North? An Analysis of Norwegian Mitigation Strategies
(2024)Russia’s invasion of Ukraine has created the most precarious security situation in Europe, including the High North, since the Second World War. This article studies how Norway manages High North security dilemmas in the ... -
Forsvarsanalysen 2024 – Utvidet sammendrag av FFI-rapport 24/00298
(2024-02-13)Hvordan kan Forsvaret styrkes? I år legger Forsvarsanalysen vekt på to forhold som kan påvirke den kommende langtidsplanen: følgene av Russlands angrep på Ukraina, og rivaliseringen mellom stormaktene USA og Kina i ... -
Forsvarsanalysen 2024
(2024-02-13)FFI-prosjektet «Strategiske forsvarsanalyser» ble opprettet 1. januar 2021. Forsvarsdepartementet (FD) er oppdragsgiver, og forsvarssjefen er sektorens hovedrepresentant. Prosjektets hovedprodukt er en årlig analyse som ...