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.

Data collection and simulation of high range resolution laser radar for surface mine detection

Abstract: Rapid and efficient detection of surface mines, IED's (Improvised Explosive Devices) and UXO (Unexploded Ordnance) is of high priority in military conflicts. High range resolution laser radars combined with passive hyper/multispectral sensors offer an interesting concept to help solving this problem. This paper reports on laser radar data collection of various surface mines in different types of terrain. In order to evaluate the capability of 3D imaging for detecting and classifying the objects of interest a scanning laser radar was used to scan mines and surrounding terrain with high angular and range resolution. These data were then fed into a laser radar model capable of generating range waveforms for a variety of system parameters and combinations of different targets and backgrounds. We can thus simulate a potential system by down sampling to relevant pixel sizes and laser/receiver characteristics. Data, simulations and examples will be presented.

Electrical and optical properties of gold-doped n-type silicon

Abstract: Different measurement techniques, both electrical and optical, were utilized in this work to characterize gold diffusion in n‐type, float‐zoned silicon in the temperature range 600–1150 °C. In the lower temperature region (≤750 °C), the gold diffusion is observed by the introduction of the Au acceptor state at 0.53 eV below the conduction band, and is correlated to the electrical behavior of the samples deduced from Hall effect and resistivity data. Also, the effects of Au diffusion on the free‐carrier concentration and mobilities are discussed. It was shown that high temperatures and long times for gold diffusion change the conductivity type in the samples from n to p. In the samples that converted to p type, a limiting room‐temperature resistivity of 2.0×103 Ω cm was attained, when the conduction is mainly influenced by the Au‐related deep electronic states in the band gap. In this case, the diffusion mechanism is also investigated by secondary ion mass spectroscopy data determining the equilibrium Au solubility, which is close to the equilibrium solubility of interstitial gold. Low‐temperature photoluminescence measurements have shown that the intensity of the lines often attributed to dislocations, increases significantly by gold diffusion in the lower temperature region. At higher diffusion temperatures, a decrease of the dislocation‐related lines was found, associated with formation of gold‐related precipitates. Introducing an inhomogeneous internal stress distribution in the Si matrix, these precipitates cause line shifts as well as line broadenings of the free exciton, the phosphorus bound exciton, and the electron‐hole droplet photoluminescence emissions. The concentration of substitutional phosphorus is found to decrease with increasing diffusion temperatures.

Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates.

Abstract: Betula pendula (Silver birch) trees growing on two contaminated sites were evaluated to assess their capacity to phytoscreen and phytoremediate chlorinated aliphatic compounds and heavy metals. Both locations are industrially-contaminated properties in central Sweden. The first was the site of a trichloroethylene (TCE) spill in the 1980s while the second was polluted with heavy metals by burning industrial wastes. In both cases, sap and sapwood from Silver birch trees were collected and analyzed for either chlorinated aliphatic compounds or heavy metals. These results were compared to analyses of the surface soil, vadose zone pore air and groundwater. Silver birch demonstrated the potential to phytoscreen and possibly phytoremediate TCE and related compounds, but it did not demonstrate the ability to effectively phytoextract heavy metals when compared with hyperaccumulator plants. The capacity of Silver birch to phytoremediate TCE appears comparable to tree species that have been employed in field-scale TCE phytoremediation efforts, such as Populus spp. and Eucalyptus sideroxylon rosea.

An empirical test of the accuracy of an attack graph analysis tool

Abstract: – The purpose of this paper is to test the practical utility of attack graph analysis. Attack graphs have been proposed as a viable solution to many problems in computer network security management. After individual vulnerabilities are identified with a vulnerability scanner, an attack graph can relate the individual vulnerabilities to the possibility of an attack and subsequently analyze and predict which privileges attackers could obtain through multi-step attacks (in which multiple vulnerabilities are exploited in sequence). , – The attack graph tool, MulVAL, was fed information from the vulnerability scanner Nexpose and network topology information from 8 fictitious organizations containing 199 machines. Two teams of attackers attempted to infiltrate these networks over the course of two days and reported which machines they compromised and which attack paths they attempted to use. Their reports are compared to the predictions of the attack graph analysis. , – The prediction accuracy of the attack graph analysis was poor. Attackers were more than three times likely to compromise a host predicted as impossible to compromise compared to a host that was predicted as possible to compromise. Furthermore, 29 per cent of the hosts predicted as impossible to compromise were compromised during the two days. The inaccuracy of the vulnerability scanner and MulVAL’s interpretation of vulnerability information are primary reasons for the poor prediction accuracy. , – Although considerable research contributions have been made to the development of attack graphs, and several analysis methods have been proposed using attack graphs, the extant literature does not describe any tests of their accuracy under realistic conditions.