Swedish Defence Research Agency

About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Laser. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.

The Community Mechanism for Civil Protection and the European Union Solidarity Fund

Abstract: This chapter gives an introduction to the EU Community Mechanism for Civil Protection (the Mechanism) and the EU Solidarity Fund (EUSF). The Mechanism is a structure that aims to facilitate civil protection assistance between Member States and to third countries in response to major crises, whereas the EUSF makes possible financial support for actions undertaken in the immediate recovery phase of a crisis. The Mechanism may be described as the most practical dimension of EU crisis management and also as one of the first initiatives in the area. Although the Mechanism and the EUSF were established separately, roughly ten years apart, and constitute two different EU crisis management instruments, the context in which they were founded was similar, as are their roles in the wider development of crisis management in the EU.

Polarization properties of a nematic liquid-crystal spatial light modulator for phase modulation

Abstract: The polarization properties of a nematic zero-twist liquid-crystal (NLC) spatial light modulator (SLM) were studied. A large ratio between the liquid-crystal (LC) layer thickness and the pixel pitch combined with spatial variations in the applied electric field causes fringing fields between pixels. Depending on the LC alignment, the electric field components within the LC layer can result in a twist deformation. The produced inhomogeneous optical anisotropy affects the polarization of light propagating through the device. We experimentally examined polarization effects in different diffraction orders for both binary and blazed phase gratings. Simulations of the LC deformation together with finite-difference time-domain simulations for the optical propagation were used to calculate the corresponding far-field intensities. It was demonstrated how rigorous simulations of the NLC SLM properties can be used to understand the polarization features of different diffraction orders.

Highly interacting regions of the human genome are enriched with enhancers and bound by DNA repair proteins.

Abstract: In specific cases, chromatin clearly forms long-range loops that place distant regulatory elements in close proximity to transcription start sites, but we have limited understanding of many loops identified by Chromosome Conformation Capture (such as Hi-C) analyses. In efforts to elucidate their characteristics and functions, we have identified highly interacting regions (HIRs) using intra-chromosomal Hi-C datasets with a new computational method based on looking at the eigenvector that corresponds to the smallest eigenvalue (here unity). Analysis of these regions using ENCODE data shows that they are in general enriched in bound factors involved in DNA damage repair and have actively transcribed genes. However, both highly transcribed regions as well as transcriptionally inactive regions can form HIRs. The results also indicate that enhancers and super-enhancers in particular form long-range interactions within the same chromosome. The accumulation of DNA repair factors in most identified HIRs suggests that protection from DNA damage in these regions is essential for avoidance of detrimental rearrangements.

Tandem PPKTP and ZGP OPO for mid-infrared generation

Abstract: Efficient laser sources in the 3 - 5 μm wavelength range are needed for directed infrared countermeasures, but also have applications in remote-sensing, medicine and spectroscopy. We present new results on our tandem optical parametric oscillator (OPO) scheme for converting the radiation from a 1.06 μm Nd3+-laser to the mid-infrared. Multi Watt level output power in the 3-5 μm range at 20 kHz pulse repetition frequency is reported. Our setup uses a type I quasi phase-matched PPKTP crystal in a near degenerate OPO to generate 2.13 μm radiation. A volume Bragg grating resonant close to, but not exactly at the degenerate wavelength, is used as a cavity mirror to reduce the bandwidth and ensure singly resonant operation. Both signal and idler from the PPKTP OPO are used to pump a ZGP OPO generating high power radiation in the 3-5 μm region. Using this scheme for each pump photon it is possible to generate four photons for each pump photon, all in the interesting wavelength range, thus enabling high efficiency conversion.

A Method for Community Detection in Uncertain Networks

Abstract: Social network analysis can be an important help for military and criminal intelligence analysis. In real world applications, there is seldom complete knowledge about the network of interest -- we only have partial and incomplete information about the nodes and networks present. Community detection in networks is an important area of current research in social network analysis with many applications. Finding community structures is however a challenging task and despite significant effort no satisfactory method has been found. Here we study the problem of community detection in noisy and uncertain networks with missing and false edges and propose methods for detecting community structures in them. The method is based on sampling from an ensemble of certain networks that are consistent with the available information about the uncertain networks.