Solberg L.E.,University of Oslo |
Hamran S.-E.,Forsvarets Forskningsinstitutt |
Hamran S.-E.,University of Oslo |
Balasingham I.,University of Oslo |
Balasingham I.,Norwegian University of Science and Technology
ACM International Conference Proceeding Series | Year: 2011
This paper studies estimation of the dynamic aorta radius in a realistic geometry where radius variation is used as an indirect measure of central blood pressure. Four different radius estimation approaches were studied where their performance in terms of precision and sensitivity was compared. As a basis for estimation simulations, finite-difference, time-domain electromagnetic simulations of a realistic human model have been performed. Radius estimation should be based on identifying the front and rear reflections from the aorta, however the temporal sensitivity of the front reflection from the aorta is weak and non-linear; therefore robustness of radius estimates is compromised. Nonetheless, this does not preclude using the sensitivity of the rear reflections as a proxy of aorta diameter variation combined with Moens-Korteweg's relationship to perform estimations of mean pressure. Proxies of radial changes are observable and for a precision of around 0.1 mm, the results show that an emitted energy to receiver noise spectral density ratio between 110 dB and 130 dB should be sufficient, depending on the estimator. © 2011 ACM. Source
Forsvarets Forskningsinstitutt | Date: 2012-07-11
Method for collecting information from other radio transmitters and/or receivers for the purpose of coordinating and controlling the interference between transmitters and receivers. The method comprises discovering other radio transmitters and receivers in a network. Peer-to-peer communication is used over the Internet when determining relevant neighboring nodes for own communication and performing resource management for the set of radio transmitters and receivers.
Forsvarets Forskningsinstitutt | Date: 2014-03-13
An imager contains an image sensor with laterally varying spectral response. The imager is scanned over a scene or object to form a spectral image. The spectral responses are repeated at different positions in the field of view so as to reduce the effect of scene nonidealities, such as angle dependence or temporal variation, on the spectral image data. A part of the image sensor may be used for conventional two-dimensional imaging. This part of the image sensor may be used to estimate the scene geometry and scan movement, enabling further improvement in the spectral integrity.
Anschutz H.,Norwegian Polar Institute |
Anschutz H.,Norwegian Geotechnical Institute |
Sinisalo A.,University of Oslo |
Isaksson E.,Norwegian Polar Institute |
And 7 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2011
Volcanic signatures in ice-core records provide an excellent means to date the cores and obtain information about accumulation rates. From several ice cores it is thus possible to extract a spatio-temporal accumulation pattern. We show records of electrical conductivity and sulfur from 13 firn cores from the Norwegian-USA scientific traverse during the International Polar Year 2007-2009 (IPY) through East Antarctica. Major volcanic eruptions are identified and used to assess century-scale accumulation changes. The largest changes seem to occur in the most recent decades with accumulation over the period 1963-2007/08 being up to 25% different from the long-term record. There is no clear overall trend, some sites show an increase in accumulation over the period 1963 to present while others show a decrease. Almost all of the sites above 3200 m above sea level (asl) suggest a decrease. These sites also show a significantly lower accumulation value than large-scale assessments both for the period 1963 to present and for the long-term mean at the respective drill sites. The spatial accumulation distribution is influenced mainly by elevation and distance to the ocean (continentality), as expected. Ground-penetrating radar data around the drill sites show a spatial variability within 10-20% over several tens of kilometers, indicating that our drill sites are well representative for the area around them. Our results are important for large-scale assessments of Antarctic mass balance and model validation. Copyright 2011 by the American Geophysical Union. Source
Nesser P.,Forsvarets Forskningsinstitutt
Terrorism and Political Violence | Year: 2011
The article explores ideological fault lines among Sunni Muslim militants (jihadists) in Europe since the mid-1990s. It argues there have been disputes among the militants about whether to prioritize local struggles or Al Qaeda's global war, and about the legitimacy of launching terrorist attacks in European states offering political asylum to Muslims. It concludes that Europe's militants have become more ideologically unified in conjunction with the invasions of Afghanistan, Iraq, and the Mohammed drawings, seeing European countries as legitimate and prioritized targets, and identifying with Al Qaeda. © Taylor & Francis Group, LLC. Source