Stig Andersson

Learn More
Kyuho Lee,1 André K. Kelkkanen,2,3 Kristian Berland,3 Stig Andersson,4 David C. Langreth,1 Elsebeth Schröder,3 Bengt I. Lundqvist,2,3,5 and Per Hyldgaard3 1Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA 2Center for Atomic-scale Materials Design, Department of Physics, Technical University of Denmark, DK-2800(More)
Code injection vulnerabilities continue to prevail. Attacks of this kind such as stack buffer overflows and heap buffer overflows account for roughly half of the vulnerabilities discovered in software every year. The research presented in this paper extends earlier work in the area of code injection attack detection in UNIX environments. It presents a(More)
Buffer overflow attacks continue to be a major security problem and detecting attacks of this nature is therefore crucial to network security. Signature based network based intrusion detection systems (NIDS) compare network traffic to signatures modelling suspicious or attack traffic to detect network attacks. Since detection is based on pattern matching, a(More)
Most rating scales for affective disorders measure either depressive or hypomanic/manic symptoms and there are few scales for hypomania/mania in a self-rating format. We wanted to develop and validate a self-rating scale for comprehensive assessment of depressive, manic/hypomanic and mixed affective states. We developed an 18-item self-rating scale starting(More)
Intrusion detection systems (IDSs) are widely recognised as the last line of defence often used to enable incident response when intrusion prevention mechanisms are ineffective, or have been compromised. A signature based network IDS (NIDS) which operates by comparing network traffic to a database of suspicious activity patterns (known as signatures) is a(More)
Detailed physisorption data from experiment for the H(2) molecule on low-index Cu surfaces challenge theory. Recently, density functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels(More)
Ortho-para conversion of H2 adsorbed at the step atoms of a Cu(510) surface proceeds with a short conversion time constant around 1 s as observed in electron-energy-loss measurements of rotational populations. We suggest that this rapid conversion is related to the special character of the adsorption state, which involves a short H2-Cu bond length of 1.8 A.(More)
Molecular dynamics (MD) calculations have been performed to study the ultraviolet (UV) photodissociation of D(2)O in an amorphous D(2)O ice surface at 10, 20, 60, and 90 K, in order to investigate the influence of isotope effects on the photodesorption processes. As for H(2)O, the main processes after UV photodissociation are trapping and desorption of(More)
Using infrared spectroscopy and low electron energy diffraction, we have investigated the adsorption of N(2), at 30 K, on the Pt(111) and the Pt(111)(1x1)H surfaces. At monolayer coverage, N(2) orders in commensurate (3x3) structures on both surfaces, and we propose that the unit cells contain four molecules in each case. The infrared spectra reveal that(More)
The adsorption of O2 on the Pt(111) surface, with particular emphasis on the influence of substrate temperature, has been studied by infrared reflection absorption spectroscopy (IRAS). In the temperature range 30-90 K the IRAS spectra reveal three different molecular adsorption states. A physisorbed state appears below 40 K while chemisorbed peroxo- and(More)