Showing papers by "Swedish Defence Research Agency published in 2022"
TL;DR: In this paper, the Raman peak from CaDPA (calcium dipicolinic acid), which is a chemical protecting the spore core, was measured using laser power.
12 citations
TL;DR: The Agile Response Capability (ARC) guidance material as discussed by the authors was developed from a literature study and a number of case studies that combined past event analysis, interviews, focus groups, workshops, questionnaires, and exercise observation methodologies.
Abstract: Aviation is a highly inter-connected system. This means that a problem in one area may cause effects in other countries or parts of the Air Transport System (ATS). Examples range from local air traffic disruptions to the 2010 volcanic ash crisis. Agility, like resilience, refers to the ability to cope with dynamics and complexity in a flexible manner, by adjusting and adapting performance and the organization of work to fit changing demands. The aim of this work is to help ATS organizations with increasing their agility in the face of crises and challenges. To this end, this article presents the Agile Response Capability (ARC) guidance material. ARC was developed from a literature study and a number of case studies that combined past event analysis, interviews, focus groups, workshops, questionnaires, and exercise observation methodologies. ARC aims to help aviation organizations to set up, run, and evaluate exercises promoting agility to handle disturbances and crises, and to enable structured pro-active and retrospective analysis of scenarios and actual events. The elements and steps of the ARC approach are illustrated and exemplified with data from three case studies. The ARC methodology facilitates more agile and resilient ways of responding to the fundamental and novel surprises that have become almost commonplace in the past decade, and are likely to continue to do so.
4 citations
TL;DR: In this article , a national foodborne outbreak resulted from infection with Cryptosporidium parvum via romaine lettuce, with the main goal to trace the source of the parasite.
3 citations
TL;DR: Rosenqvist et al. as discussed by the authors developed a proof-of-concept modeling capability that incorporates a detailed 3D structure of Earth's electrical conductivity in a geomagnetically induced current estimation procedure (GIC-SMAP).
Abstract: Rosenqvist and Hall (2019), https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018SW002084 developed a proof-of-concept modeling capability that incorporates a detailed 3D structure of Earth's electrical conductivity in a geomagnetically induced current estimation procedure (GIC-SMAP). The model was verified based on GIC measurements in northern Sweden. The study showed that southern Sweden is exposed to stronger electric fields due to a combined effect of low crustal conductivity and the influence of the surrounding coast. This study aims at further verifying the model in this region. GIC measurements on a power line at the west coast of southern Sweden are utilized. The location of the transmission line was selected to include coast effects at the ocean-land interface to investigate the importance of using 3D induction modeling methods. The model is used to quantify the hazard of severe GICs in this particular transmission line by using historic recordings of strong geomagnetic disturbances. To quantify a worst-case scenario GICs are calculated from modeled magnetic disturbances by the Space Weather Modeling Framework based on estimates for an idealized extreme interplanetary coronal mass ejection. The observed and estimated GIC based on the 3D GIC-SMAP procedure in the transmission line in southern Sweden are in good agreement. In contrast, 1D methods underestimate GICs by about 50%. The estimated GICs in the studied transmission line exceed 100 A for one of 14 historical geomagnetic storm intervals. The peak GIC during the sudden impulse phase of a “perfect” storm exceeds 300 A but depends on the locality of the station as the interplanetary magnetic cloud hits Earth.
3 citations
1 citations
30 Aug 2022
TL;DR: In this paper , the authors investigated the implications of time variability in the underwater acoustic channel on coded multiple tone frequency-shift keying (FSK) that uses a Rice model on narrow toneband envelopes.
Abstract: This paper investigates the implications of time variability in the underwater acoustic channel on coded multiple tone frequency-shift keying (FSK) that uses a Rice model on narrow toneband envelopes. It is evaluated with Convolution coded frequency parallel binary FSK in the 5 Watermark replay channels, in terms of the bit error rate over the noise measure E b /N 0 , where the model parameters are tracked using known pilots. The performance varies with pilot sparseness; however, it is significantly improved by limiting the likelihood input signalto-noise ratio, which enables using a simple data model with minimal estimation overhead, and pilots can be separated by up to 10 [s].
10 Sep 2022
30 Nov 2022
TL;DR: In this article , the impact of anomalous propagation on ground clutter, measured with horizontal and vertical polarization, was compared but no clear difference was found, and an analysis of the data revealed a strong seasonal cycle and weaker diurnal cycle in ground clutter from coastal regions across nearby waters.
Abstract: Abstract. Radio waves propagating in the atmosphere are affected by the prevailing atmospheric state. The state of the atmosphere can cause radio waves to refract more or less towards the ground. When the refractive index of the atmosphere differs from standard atmospheric conditions the propagation is called anomalous. Radars which are affected by anomalous propagation can receive ground clutter far beyond the radar horizon. In this work 4.5 years of data from five operational Swedish C-band dual polarization weather radars are presented. Analyses of the data reveal a strong seasonal cycle and weaker diurnal cycle in ground clutter from coastal regions across nearby waters. The impact of anomalous propagation on ground clutter, measured with horizontal and vertical polarization, was compared but no clear difference was found.