| 1. |
- Almgren, Jonas, et al.
(författare)
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SICStus Prolog library manual, version 2.1 #8
- 1993. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This Manual corresponds to SICStus Prolog release 2.1. #8 The Prolog library comprises a number of packages which are thought to be useful in a number of applications. Note that the predicates in the Prolog library are built-in predicates. One has to explicity load each package to get access to its predicates. To load a library package Package, you will normally enter a query. I ?- use_module(library(Package)). Library packages may be compiled and consulted as well as loaded.
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| 2. |
- Andersson, Johan, et al.
(författare)
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SICStus Prolog user's manual, version 2.1 #8
- 1993. - 1
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This Manual corresponds to SICStus Prolog release 2.1. #8 Prolog is a simple but powerful programming language developed at the University of Marseilles (Prolog : Manuel de Reference et d'Utilisation by P.Roussel, Groupe d'Intelligence Artificielle, Marseille-Luminy, 1975), as a practical tool for programming in Logic (Logic for Problem Solving by R.A. Kowalski, DCL Memo 75, Dept. of Artificial Intelligence, University of Edinburgh, March, 1974.)) From a user's point of view the major attraction of the language is ease of programming. Clear, readable, concise programs can be written quickly with few errors. This manual describes a Prolog system developed at the Swedish Institute of Computer Science in collaboration with Ericsson Telecom AB, NobelTech Systems AB, Infologics AB and Televerket under the IT4 program. The system consists of a WAM emulator written in C, a library and runtime system written in C and Prolog and an interpreter and a compiler written in Prolog. The Prolog engine is a Warren Abstract Machine (WAM) emulator defined by D:H:D: Warren in An Abstract Prolog Instruction Set, Tech. Note 309, International, Menlo Park, CA, 1983. Two modes of compilation are available: in-core i.e. incremental, and file-to-file.
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| 3. |
- Behar, Etienne, et al.
(författare)
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Mass-loading of the solar wind at 67P/Churyumov-Gerasimenko : Observations and modelling
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 596
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Tidskriftsartikel (refereegranskat)abstract
- Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft.Aims. Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret the deflection and deceleration of the flow expected from ionization of neutral cometary particles within the undisturbed solar wind.Methods. We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the solar wind and the comet atmosphere.Results. The solar wind deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled solar wind protons. According to our model, energy and momentum are transferred from the solar wind to the coma in a single region, centered on the nucleus, with a size in the order of 1000 km. This interaction affects, over larger scales, the downstream modeled solar wind flow. The energy gained by the cometary ions is a small fraction of the energy available in the solar wind.Conclusions. The deflection of the solar wind is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the solar wind.
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| 4. |
- Behar, Etienne, et al.
(författare)
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Solar wind dynamics around a comet : A 2D semi-analytical kinetic model
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 620
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Tidskriftsartikel (refereegranskat)abstract
- Aims.We aim at analytically modelling the solar wind proton trajectories during their interaction with a partially ionised cometaryatmosphere, not in terms of bulk properties of the flow but in terms of single particle dynamics.Methods.We first derive a generalised gyromotion, in which the electric field is reduced to its motional component. Steady-stateis assumed, and simplified models of the cometary density and of the electron fluid are used to express the force experienced byindividual solar wind protons during the interaction.Results.A three-dimensional (3D) analytical expression of the gyration of two interacting plasma beams is obtained. Applying it to acomet case, the force on protons is always perpendicular to their velocity and has an amplitude proportional to 1/r2. The solar winddeflection is obtained at any point in space. The resulting picture presents a caustic of intersecting trajectories, and a circular regionis found that is completely free of particles. The particles do not lose any kinetic energy and this absence of deceleration, togetherwith the solar wind deflection pattern and the presence of a solar wind ion cavity, is in good agreement with the general results of theRosettamission.Conclusions.The qualitative match between the model and thein situdata highlights how dominant the motional electric field isthroughout most of the interaction region for the solar wind proton dynamics. The model provides a simple general kinetic descriptionof how momentum is transferred between these two collisionless plasmas. It also shows the potential of this semi-analytical modelfor a systematic quantitative comparison to the data.
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| 5. |
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| 6. |
- Bertilsson, Kent, et al.
(författare)
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Monte Carlo simulation of vertical MESFETs in 2H, 4H and 6H-SiC
- 2001
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Ingår i: Diamond and related materials. - 0925-9635 .- 1879-0062. ; 10:3-7, s. 1283-1286
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Tidskriftsartikel (refereegranskat)abstract
- The 4H-SiC static induction transistor (SIT) is a very competitive device for high frequency and high power applications (3-6 GHz range). The large breakdown voltage and the high thermal conductivity of 4H-SiC allow transistors with extremely high current density at high voltages. The SIT transistor shows better output power capabilities but the unity current-gain frequency is lower compared to a MESFET device. In this work we show, using a very accurate numerical model, that a compromise between the features given by the SIT structure and the ordinary MESFET structure can be obtained using the vertical MESFET structure. The device dimension has been selected very aggressively to demonstrate the performance of an optimized technology. We also present results from drift-diffusion simulations of devices, using transport parameters obtained from the Monte Carlo simulation. The simulations indicate that 2H-SiC is superior to both 4H and 6H-SiC for vertical devices. For lateral devices, 2H-SiC is slightly faster compared to an identical 4H-SiC device
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| 7. |
- Bertilsson, Kent, et al.
(författare)
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The Effect of Different Transport Models in Simulation of High Frequency 4H-SiC and 6H-SiC Vertical MESFETs
- 2001
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Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 45:5, s. 645-653
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Tidskriftsartikel (refereegranskat)abstract
- A full band Monte Carlo (MC) study of the high frequency performance of a 4H-SiC Short channel vertical MESFET is presented. The MC model used is based on data from a full potential band structure calculation using the local density approximation to the density functional theory. The MC results have been compared with simulations using state of the art drift-diffusion and hydrodynamic transport models. Transport parameters such as mobility, saturation velocity and energy relaxation time are extracted from MC simulations
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| 8. |
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| 9. |
- Ciamulski, T, et al.
(författare)
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Parallel FDTD Processing on Shared Memory Computers
- 2007
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Ingår i: The 23rd annual review of Progress in Applied computational electromagnetics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An ongoing European project on customization of electromagnetic simulation tool is ready to present significantly improved performance of parallel version of a professional FDTD simulator. The first stage of the work is concentrated on solution for computers with the shared memory architecture. The relevance and feasibility study of the solution for contemporary computers is shown. Possible ways to reach further performance improvements as well as solutions for distributed memory machines are discussed.
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| 10. |
- Dubaric, Ervin, et al.
(författare)
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Monte Carlo simulations of the imaging properties of scintillator coated X-ray pixel detectors
- 2000
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Ingår i: IEEE Nuclear Science Symposium and Medical Imaging Conference. - : IEEE conference proceedings. - 0780365038 ; , s. 6/282-6/285
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Konferensbidrag (refereegranskat)abstract
- The imaging properties of X-ray pixel detectors depend on the quantum efficiency for X-rays, the generated signal for each X-ray photon and the distribution of the generated signal between different pixels. In a scintillator coated device the signal is generated both by X-ray photons captured in the scintillator and by X-ray photons captured directly in the semiconductor. Hence, the signal-to-noise ratio (SNR) in the image is then a function of the number of photons captured in each of these processes, and the yield of each process, in terms of electron-hole pairs (EHPs) produced in the semiconductor. The full process from the absorption of the X-ray photon to the final signal read out from the detector has been simulated with a combination of the Monte Carlo program MCNP and the commercial carrier transport simulation tool MEDICI. An in house program calculating the light transport between the scintillator and the semiconductor serves as a link
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