| 1. |
- Akkurt, I, et al.
(författare)
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Photoneutron yields from tungsten in the energy range of the giant dipole resonance
- 2003
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 48:20, s. 3345-3352
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Tidskriftsartikel (refereegranskat)abstract
- Photoneutron production on the nuclei of high-Z components of medical accelerator heads can lead to a significant secondary dose during a course of bremsstrahlung radiotherapy, However, a quantitative evaluation of secondary neutron dose requires improved data on the photoreaction yields. These have been measured as a function of photon energy, neutron energy and neutron angle for W-nat, using tagged photons at the MAX-Lab photonuclear facility in Sweden. This work presents neutron yields for W-nat(gamma, n) and compares these with the predictions of the Monte Carlo code MCNP-GN, developed specifically to simulate photoneutron production at medical accelerators.
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| 2. |
- Almgren, Magnus, 1972, et al.
(författare)
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Implications of IDS Classification on Attack Detection
- 2003
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Ingår i: Nordic Workshop on Secure IT Systems (NordSec). - 8299398045 ; , s. 57--70-
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Konferensbidrag (refereegranskat)abstract
- Accurate taxonomies are critical for the advancement of research fields. Taxonomies for intrusion detection systems (IDSs) are not fully agreed upon, and further lack convincing motivation of their categories. We survey and summarize previously made taxonomies for intrusion detection. Focusing on categories relevant for detection methods, we extract commonly used concepts and define three new attributes: the reference model type, the reference model generation process, and the reference model updating strategy. Using our framework, the range of previously used terms can easily be explained. We study the usefulness of these attributes with two empirical evaluations. Firstly, we use the taxonomy to create a survey of existing research IDSs, with a successful result, i.e. the IDSs are well scattered in the defined space. Secondly, we investigate whether we can reason about the detection capability based on detection method classes, as defined by our framework. We establish that different detection methods vary in their capability to detect specific attack types. The reference model type seems better suited than reference model generation process for such reasoning. However, our results are tentative and based on a relatively small number of attacks.
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| 3. |
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| 4. |
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| 5. |
- Bucht, Charlotte, et al.
(författare)
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Why don't prices fall in a recession? : financial constraints, investment, and customer relations
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We construct a model of a financially constrained firm making pricing and investment decisions. The firm operates in a market where customers respond slowly to price changes and there are implementation lags in investment (time to build). Our model implies that the markup over marginal cost is counter-cyclical, the product price responds slowly to demand shocks, and quickly to cost shocks, and the price is strongly related to investment. Estimating the decision rules on aggregate data for Swedish industry, we find that the qualitative results are in line with our model.
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| 6. |
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| 7. |
- Lundin, Magnus, et al.
(författare)
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Compton scattering from the deuteron and extracted neutron polarizabilities
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 90:19
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Tidskriftsartikel (refereegranskat)abstract
- Differential cross sections for Compton scattering from the deuteron were measured at MAX-Lab for incident photon energies of 55 and 66 MeV at nominal laboratory angles of 45degrees, 125degrees, and 135degrees. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and the difference of the isospin-averaged nucleon polarizabilities, alpha(N) + beta(N) = 17.4 +/- 3.7 and alpha(N) - beta(N) = 6.4 +/- 2.4 (in units of 10(-4) fm(3)), have been determined. By combining the latter with the global-averaged value for alpha(p) - beta(p) and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of alpha(n) = 8.8 +/- 2.4(total) +/- 3.0(model) and beta(n) = 6.5 -/+ 2.4(total) -/+ 3.0(model), respectively.
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| 8. |
- Lundin, Magnus
(författare)
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Compton Scattering from the Deuteron at Low Energies
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A series of three Compton scattering experiments on deuterium have been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 50 < Eg < 70 MeV tagged photons were scattered from a liquid deuterium target and detected simultaneously in three (10"x10") NaI detectors. The average laboratory angles investigated were 45, 125 and 135 deg. The influence of the inelastic contribution was minimized by implementing a narrow elastic fit-region in the missing energy spectra. Absolute cross sections were extracted for average photon energies of 55 and 66 MeV at each angle and for each experiment. The extracted cross sections are in good agreement with those measured at Illinois by Lucas et al. The difference between the electric and magnetic isospin-averaged polarizabilities of the nucleon inside the deuteron, was varied within the calculations of Levchuk and L'vov to best reproduce the data, holding the sum fixed at 14.6 (10-4 fm3). The result implies that the electric polarizability of the neutron is the same as that of the proton within the experimental uncertainties. The result also indicates that the magnetic polarizability of the neutron is larger than that of the proton.
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| 9. |
- Lundin, Margareta, 1967, et al.
(författare)
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Life Cycle Assessment of Wastewater Systems - Influence of System Boundaries and Scale on Calculated Environmental Loads
- 2000
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Ingår i: Environmental Science & Technology. ; 34, s. 180-186
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Tidskriftsartikel (refereegranskat)abstract
- Life cycle assessment (LCA) methodology was used to compare the environmental loads from wastewater systems with different technical solutions. This study compared proposed conventional wastewater systems, both large and small scale, with separation systems: one in which urine is handled separately and one in which black water is treated in a liquid composting process. The study showed that large economies of scale, in environmental terms, could be gained both for the operation and for the construction phase. The separation systems outperformed the conventional systems by showing lower emissions to water and more efficient recycling of nutrients to agriculture, especially of nitrogen but also of phosphorus. This implies that the use of separation systems could significantly reduce the need for, and hence the production of, mineral fertilizers and thus reduce the overall use of energy and phosphate minerals. The combination of large-scale wastewater treatment and urine separation was found to be especially advantageous in these respects. It is concluded that some of the most important environmental advantages of separation systems emerge only when models of wastewater systems are expanded to also include potential effects on the production of fertilizers.
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| 10. |
- Lundin, Magnus, et al.
(författare)
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Price and investment dynamics : an empirical analysis of plant level data
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Price and investment equations are estimated using a unique data set for Swedish manufacturing plants. The empirical specification is based on a theoretical model of a financially constrained firm selling its output in a customer market. We find that, as predicted by our theoretical model, prices respond strongly to cost shocks but are not much affected by variations in demand and high predetermined investment is associated with a higher price.
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