| 1. |
- Dey, Anil, et al.
(author)
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Laboratory instructions as a cause of student dissonance
- 2010
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In: [Host publication title missing].
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Conference paper (peer-reviewed)abstract
- Improving the quality of education is the goal of all pedagogical research. By using student surveys and course evaluations problem areas can be identified in most courses offered by universities. In this paper we perform a large-scale student survey in order to find the causes of, and remedies to, a widespread student dissonance in a mandatory course with over 100 students at Lund University. Our research shows that aiming for deeper learning, without providing time and a stimulating environment, can be worse than settling for expository learning. This problem has persisted for years despite attempts by the course administrators to solve the problem. We propose that major improvements can be achieved, both in learning and pass rates, primarily by improving the lab instructions but also by using a more intellectually stimulating lab equipment.
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| 2. |
- Brorsson, Joakim, et al.
(author)
-
Guarding the Guards: Accountable Authorities in VANETs
- 2019
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In: 2018 IEEE Vehicular Networking Conference (VNC). - 9781538694282
-
Conference paper (peer-reviewed)abstract
- In this paper we present an approach to gaining increased anonymity from authorities within a VANET. Standardization organizations and researchers working on VANETs recognize privacy as highly important. However, most research focuses on privacy from other vehicles and external attackers, as opposed to privacy from system-administrating authorities. Our proposed solution forces authorities to resolve identities, i.e. de-anonymize vehicles, in public. It thereby creates a public log of identity resolutions and offers end-users a tool with which they can both validate the authorities' reasons for resolving identities and measure the extent to which such power is exercized.
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| 3. |
- Da Pieve, Fabiana, et al.
(author)
-
Electronic structure calculations of mercury mobilization from mineral phases and photocatalytic removal from water and the atmosphere
- 2014
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In: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 493, s. 596-605
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Journal article (peer-reviewed)abstract
- Mercury is a hazardous environmental pollutant mobilized from natural sources, and anthropogenically contaminated and disturbed areas. Current methods to assess mobility and environmental impact are mainly based on field measurements, soil monitoring, and kinetic modelling. In order to understand in detail the extent to which different mineral sources can give rise to mercury release it is necessary to investigate the complexity at the microscopic level and the possible degradation/dissolution processes. In this work, we investigated the potential for mobilization of mercury structurally trapped in three relevant minerals occurring in hot spring environments and mining areas, namely, cinnabar (alpha-HgS), corderoite (alpha-Hg3S2Cl2), and mercuric chloride (HgCl2). Quantum chemical methods based on density functional theory as well as more sophisticated approaches are used to assess the possibility of a) direct photoreduction and formation of elemental Hg at the surface of the minerals, providing a path for ready release in the environment; and b) reductive dissolution of the minerals in the presence of solutions containing halogens. Furthermore, we study the use of TiO2 as a potential photocatalyst for decontamination of polluted waters (mainly Hg2+-containing species) and air (atmospheric Hg-0). Our results partially explain the observed pathways of Hg mobilization from relevant minerals and the microscopic mechanisms behind photocatalytic removal of Hg-based pollutants. Possible sources of disagreement with observations are discussed and further improvements to our approach are suggested. (C) 2014 Elsevier B.V. All rights reserved.
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| 4. |
- Ghasemi, Masoomeh, et al.
(author)
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Size- and shape-dependent phase diagram of In-Sb nano-alloys
- 2015
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:41, s. 17387-17396
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Journal article (peer-reviewed)abstract
- Nano-scale alloy systems with at least one dimension below 100 nm have different phase stabilities than those observed in the macro-scale systems due to a large surface to volume ratio. We have used the semi-empirical thermodynamic modelling, i.e. the CALPHAD method, to predict the phase equilibria of the In-Sb nano-scale systems as a function of size and shape. To calculate the size- and shape-dependent phase diagram of the In-Sb system, we have added size-dependent surface energy terms to the Gibbs energy expressions in the In-Sb thermodynamic database. We estimated the surface energies of the solution phases and of the InSb intermetallic phase using the Butler equation and DFT calculations, respectively. A melting point and eutectic point depression were observed for both nanoparticle and nanowire systems. The eutectic composition on the In-rich and Sb-rich sides of the phase diagram shifted towards higher solubility. We believe that the phase diagram of In-Sb nano-alloys is useful for an increased understanding of the growth parameters and mechanisms of InSb nanostructures.
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| 5. |
- Gonze, X., et al.
(author)
-
Recent developments in the ABINIT software package
- 2016
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In: Computer Physics Communications. - : Elsevier BV. - 0010-4655. ; 205, s. 106-131
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Journal article (peer-reviewed)abstract
- ABINIT is a package whose main program allows one to find the total energy, charge density, electronic structure and many other properties of systems made of electrons and nuclei, (molecules and periodic solids) within Density Functional Theory (DFT), Many-Body Perturbation Theory (GW approximation and Bethe-Salpeter equation) and Dynamical Mean Field Theory (DMFT). ABINIT also allows to optimize the geometry according to the DFT forces and stresses, to perform molecular dynamics simulations using these forces, and to generate dynamical matrices, Born effective charges and dielectric tensors. The present paper aims to describe the new capabilities of ABINIT that have been developed since 2009. It covers both physical and technical developments inside the ABINIT code, as well as developments provided within the ABINIT package. The developments are described with relevant references, input variables, tests and tutorials. Program summary: . Program title: ABINIT. . Catalogue identifier: AEEU_v2_0. . Program summary URL: . http://cpc.cs.qub.ac.uk/summaries/AEEU_v2_0.html . . Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. . Licensing provisions: GNU General Public License, version 3. . No. of lines in distributed program, including test data, etc.: 4845789. . No. of bytes in distributed program, including test data, etc.: 71340403. . Distribution format: tar.gz. . Programming language: Fortran2003, PERL scripts, Python scripts. . Classification: 7.3, 7.8. . External routines: (all optional) BigDFT [2], ETSF_IO [3], libxc [4], NetCDF [5], MPI [6], Wannier90 [7], FFTW [8]. . Catalogue identifier of previous version: AEEU_v1_0. . Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2582. . Does the new version supersede the previous version?: Yes. The abinit-7.10.5 version is now the up to date stable version of ABINIT. . Nature of problem: . This package has the purpose of computing accurately material and nanostructure properties: electronic structure, bond lengths, bond angles, primitive cell size, cohesive energy, dielectric properties, vibrational properties, elastic properties, optical properties, magnetic properties, non-linear couplings, electronic and vibrational life-times, and others. . Solution method: . Software application based on Density Functional Theory, Many-Body Perturbation Theory and Dynamical Mean Field Theory, pseudopotentials, with plane waves or wavelets as basis functions. . Reasons for new version: . Since 2009, the abinit-5.7.4 version of the code has considerably evolved and is not yet up to date. The abinit- 7.10.5 version contains new physical and technical features that allow electronic structure calculations impossible to carry out in the previous versions. . Summary of revisions: . •new physical features: quantum effects for the nuclei treated by the Path-integral Molecular Dynamics; finding transition states using image dynamics (NEB or string methods); two component DFT for electron-positron annihilation; linear response in a Projector Augmented-Wave approach -PAW-, electron-phonon interactions and temperature dependence of the gap; Bethe Salpeter Equation -BSE-; Dynamical Mean Field Theory (DMFT).•new technical features: development of a PAW approach for a wavelet basis; parallelisation of the code on more than 10,000 processors; new build system.•new features in the ABINIT package: tests; test farm; new tutorials; new pseudopotentials and PAW atomic data tables; GUI and postprocessing tools like the AbiPy and APPA libraries. . Running time: . It is difficult to answer to the question as the use of ABINIT is very large. On one hand, ABINIT can run on 10,000 processors for hours to perform quantum molecular dynamics on large systems. On the other hand, tutorials for students can be performed on a laptop within a few minutes. . References: . 1 http://www.gnu.org/copyleft/gpl.txt 2 http://bigdft.org 3 http://www.etsf.eu/fileformats 4 http://www.tddft.org/programs/octopus/wiki/index.php/Libxc 5 http://www.unidata.ucar.edu/software/netcdf 6 https://en.wikipedia.org/wiki/Message_Passing_Interface 7 http://www.wannier.org 8M. Frigo and S.G. Johnson, Proceedings of the IEEE, 93, 216-231 (2005). . .
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| 6. |
- Jämthagen, Christopher, et al.
(author)
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eavesROP: Listening for ROP Payloads in Data Streams
- 2014
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In: Information Security/Lecture Notes in Computer Science. - Cham : Springer International Publishing. - 0302-9743. - 9783319132563 - 9783319132570 ; 8783, s. 413-424
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Conference paper (peer-reviewed)abstract
- We consider the problem of detecting exploits based on return-oriented programming. In contrast to previous works we investigate to which extent we can detect ROP payloads by only analysing streaming data, i.e., we do not assume any modifications to the target machine, its kernel or its libraries. Neither do we attempt to execute any potentially malicious code in order to determine if it is an attack. While such a scenario has its limitations, we show that using a layered approach with a filtering mechanism together with the Fast Fourier Transform, it is possible to detect ROP payloads even in the presence of noise and assuming that the target system employs ASLR. Our approach, denoted eavesROP, thus provides a very lightweight and easily deployable mitigation against certain ROP attacks. It also provides the added merit of detecting the presence of a brute-force attack on ASLR since library base addresses are not assumed to be known by eavesROP.
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| 7. |
- Karlsson, Linus, et al.
(author)
-
Improved Greedy Nonrandomness Detectors for Stream Ciphers
- 2017
-
In: Proceedings of the 3rd International Conference on Information Systems Security and Privacy. - 9789897582097 ; 1, s. 225-232
-
Conference paper (peer-reviewed)abstract
- We consider the problem of designing distinguishers and nonrandomness detectors for stream ciphers using the maximum degree monomial test. We construct an improved algorithm to determine the subset of key and IV-bits used in the test. The algorithm is generic, and can be applied to any stream cipher. In addition to this, the algorithm is highly tweakable, and can be adapted depending on the desired computational complexity. We test the algorithm on the stream ciphers Grain-128a and Grain-128, and achieve significantly better results compared to an earlier greedy approach.
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| 8. |
- Karlsson, Linus, et al.
(author)
-
Not so greedy : Enhanced subset exploration for nonrandomness detectors
- 2018
-
In: Information Systems Security and Privacy - 3rd International Conference, ICISSP 2017, Revised Selected Papers. - Cham : Springer International Publishing. - 1865-0929. - 9783319933535 ; 867, s. 273-294
-
Conference paper (peer-reviewed)abstract
- Distinguishers and nonrandomness detectors are used to distinguish ciphertext from random data. In this paper, we focus on the construction of such devices using the maximum degree monomial test. This requires the selection of certain subsets of key and IV-bits of the cipher, and since this selection to a great extent affects the final outcome, it is important to make a good selection. We present a new, generic and tunable algorithm to find such subsets. Our algorithm works on any stream cipher, and can easily be tuned to the desired computational complexity. We test our algorithm with both different input parameters and different ciphers, namely Grain-128a, Kreyvium and Grain-128. Compared to a previous greedy approach, our algorithm consistently provides better results.
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| 9. |
- Mårsell, Erik, et al.
(author)
-
Spatial Control of Multiphoton Electron Excitations in InAs Nanowires by Varying Crystal Phase and Light Polarization
- 2018
-
In: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 18:2, s. 907-915
-
Journal article (peer-reviewed)abstract
- We demonstrate the control of multiphoton electron excitations in InAs nanowires (NWs) by altering the crystal structure and the light polarization. Using few-cycle, near-infrared laser pulses from an optical parametric chirped-pulse amplification system, we induce multiphoton electron excitations in InAs nanowires with controlled wurtzite (WZ) and zincblende (ZB) segments. With a photoemission electron microscope, we show that we can selectively induce multiphoton electron emission from WZ or ZB segments of the same wire by varying the light polarization. Developing ab initio GW calculations of first to third order multiphoton excitations and using finite-difference time-domain simulations, we explain the experimental findings: While the electric-field enhancement due to the semiconductor/vacuum interface has a similar effect for all NW segments, the second and third order multiphoton transitions in the band structure of WZ InAs are highly anisotropic in contrast to ZB InAs. As the crystal phase of NWs can be precisely and reliably tailored, our findings open up for new semiconductor optoelectronics with controllable nanoscale emission of electrons through vacuum or dielectric barriers.
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| 10. |
- Stankovski, Paul, et al.
(author)
-
An Efficient State Recovery Attack on the X-FCSR Family of Stream Ciphers
- 2014
-
In: Journal of Cryptology. - : Springer Science and Business Media LLC. - 1432-1378 .- 0933-2790. ; 27:1, s. 1-22
-
Journal article (peer-reviewed)abstract
- We describe a state recovery attack on the X-FCSR family of stream ciphers. In this attack we analyse each block of output keystream and try to solve for the state. The solver will succeed when a number of state conditions are satisfied. For X-FCSR-256, our best attack has a computational complexity of only 2^{4.7} table lookups per block of keystream, with an expected 2^{44.3} such blocks before the attack is successful. The precomputational storage requirement is 2^{33}. For X-FCSR-128, the computational complexity of our best attack is 2^{16.3} table lookups per block of keystream, where we expect 2^{55.2} output blocks before the attack comes through. The precomputational storage requirement for X-FCSR-128 is 2^{67}.
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