| 1. |
- Aad, G., et al.
(författare)
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- 2014
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Aad, G., et al.
(författare)
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- 2014
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Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368 .- 1550-7998. ; 90:11
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Aad, G., et al.
(författare)
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- 2013
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Tran, Dang Ninh
(författare)
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LSB Data Hiding in 360o Videos
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern telecommunication systems have seen an increased demand on delivering new types of digital media such as extended reality. The currently rolled out fifth generation mobile networks are expected to support virtual reality, augmented reality, and other immersive media. On the other hand, securing communication to prevent access from adversaries and hiding secret information have become an integral part of digital communications. In particular, steganography is a class of data hiding that provides covert communication between two parties such that the information exchange cannot be observed by an attacker. Because the human auditory system and human visual system are relatively insensitive to small changes in digital media, hiding secret information in digital media has increasingly been used. This thesis focuses on data hiding in 360o videos which offer large resolutions that can be used for hiding secret data. To keep the computational load of data hiding low, least significant bit (LSB) data hiding methods are considered and their performance is assessed in terms of capacity and imperceptibility. The proposed LSB data hiding methods account for the human viewing behavior of watching 360o videos on head-mounted displays (HMDs).This thesis is divided into an introduction part and a research part based on four peer-reviewed publications. The introduction provides fundamentals of data hiding, terminologies used in data hiding, LSB data hiding concepts, and performance measures used to assess data hiding methods. The first paper in the research part provides a survey on LSB data hiding in digital audio, images, videos, and three-dimensional (3D) media. The survey shows the tremendous potential of LSB data hiding in digital media and may assist in developing novel applications based on suitable performance trade-offs between data hiding attributes. It also reveals that LSB data hiding in 3D media such as 360o videos is not as developed as for conventional digital media. The second paper proposes an LSB data hiding method for 360o videos which takes into account that humans pay more attention to the equator region compared to the poles when viewing 360o videos on an HMD. The third paper presents a novel viewing direction based LSB data hiding method for 360o videos. The distributions of viewing direction frequency for latitude and longitude are used to control the amount of secret data to be hidden at the latitude, longitude, or both latitude and longitude of 360o videos. Analytical expressions for the capacity offered by this method are derived and imperceptibility is assessed through fidelity and quality metrics. The fourth paper proposes a viewing direction weighted bit plane LSB data hiding method for 360o videos that uses normalized Gaussian mixture models to control the amount of secret data and the number of bit planes used for data hiding in the latitude and longitude.
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| 5. |
- Fuller, Ursula, et al.
(författare)
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A Computing Perspective on the Bologna Process
- 2006
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Ingår i: SIGCSE Bulletin: inroads. - : Association for Computing Machinery (ACM). - 0097-8418. ; 38:4, s. 115-131
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Tidskriftsartikel (refereegranskat)abstract
- The Bologna process is intended to culminate in the formation of the European Higher Education Area (EHEA) by 2010. Its aim is to facilitate the mobility of people, the transparency and recognition of qualifications, quality and development of a European dimension to higher education, and the attractiveness of European institutions for third country students.This paper provides an overview of progress towards implementation in EHEA member states using official documents and interview data from faculty teaching computing in countries represented at the ITiCSE 2006 meeting. The key areas where the structures established by the Bologna process are problematic for computing education arise from the rapidly changing nature of the curriculum. It seems that the maturity and capability criteria, as well as the manner in which learning outcomes are specified, being developed within the Bologna process are too general. This endangers the properties of transparency and mobility that the process intends to promote.Progression and prerequisite knowledge in computing degrees can be very specific. For instance, generic learning outcomes for an introductory programming course quite rightly will not specify the programming language, or languages, used to implement algorithms. However, suppose a student intends to study an advanced algorithms and data structures course in which Java is the language of implementation which has an introductory course in programming as a prerequisite. If the introductory course language was Standard ML it is not clear that the prerequisite course actually provides the student with a suitable background. These types of complexities are typical of computing, where early subject curricula are not standardised nationally or internationally, and create significant hurdles for realising the Bologna objectives.
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| 6. |
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| 7. |
- Wang, Guangmei, et al.
(författare)
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Ionothermal Synthesis, Structures, and Magnetism of Three New Open Framework Iron Halide-Phosphates
- 2019
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 58:19, s. 13203-13212
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Tidskriftsartikel (refereegranskat)abstract
- A set of different open framework iron phosphates have been synthesized ionothermally using a task-specific ionic liquid, 1-butyl-4-methylpyridinium hexafluorophosphate, that acts in the synthesis as the reaction medium and mineralizer: (NH4)(2)Fe-2(HPO4)(PO4)Cl2F (1) and K2Fe2(HPO4(PO4)Cl2F (2) exhibit similar composition and closely related structural features. Both structures consist of {Fe-2(HPO4)(PO4)-Cl2F}(2)- macroanions and charge balancing ammonium or potassium cations. Their open framework structure contains layers and chains of corner-linked {Fe(1)O2Cl4} and {Fe(2)F2O4} octahedra, respectively, interconnected by PO4 tetrahedra forming 10-ring channels. KFe(PO3F)F-2 (3) is built up by {Fe[(PO3F)(4/3)F-2/2]}{Fe(PO3F)(2/3) F2/2F2} layers separated by K+ cations. Chains of alternating {FeF2O4} and {FeO2F4} octahedra, which are linear for 1 but undulated for 2, are linked to each other via corner-sharing {PO3F} tetrahedra with the fluorine pointing into the interlayer space. The compounds were characterized by means of single crystal and powder X-ray diffraction, infrared spectroscopy, and magnetic measurements. 1 reveals a strong ground state spin anisotropy with a spin 5/2 state and a magnetic moment of 5.3 mu(B) /Fe3+. Specific heat and magnetic data unveil three magnetic transitions at 95, 50, and 3.6 K. Compound 2 has a very similar crystal structure as compared to 1 but exhibits a different magnetic behavior: a slightly lower magnetic moment of 4.7 mu(B)/Fe3+ and a magnetic transition to a canted antiferromagnetic state below 90 K. Compound 3 exhibits typical paramagnetic behavior close to room-temperature (5.71 mu(B)/Fe3+). There are no clear indications for a phase transition down to 2 K despite strong antiferromagnetic spin-spin interactions; only a magnetic anomaly appears at 50 K in the zero-field cooled data.
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| 8. |
- Voronkov, Artem, 1990-, et al.
(författare)
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Systematic Literature Review on Usability of Firewall Configuration
- 2018
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Ingår i: ACM Computing Surveys. - New York, NY, USA : Association for Computing Machinery (ACM). - 0360-0300 .- 1557-7341. ; 50:6
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Tidskriftsartikel (refereegranskat)abstract
- Firewalls are network security components that handle incoming and outgoing network traffic based on a set of rules. The process of correctly configuring a firewall is complicated and prone to error, and it worsens as the network complexity grows. A poorly configured firewall may result in major security threats; in the case of a network firewall, an organization’s security could be endangered, and in the case of a personal firewall, an individual computer’s security is threatened. A major reason for poorly configured firewalls, as pointed out in the literature, is usability issues. Our aim is to identify existing solutions that help professional and non-professional users to create and manage firewall configuration files, and to analyze the proposals in respect of usability. A systematic literature review with a focus on the usability of firewall configuration is presented in the article. Its main goal is to explore what has already been done in this field. In the primary selection procedure, 1,202 articles were retrieved and then screened. The secondary selection led us to 35 articles carefully chosen for further investigation, of which 14 articles were selected and summarized. As main contributions, we propose a taxonomy of existing solutions as well as a synthesis and in-depth discussion about the state of the art in firewall usability. Among the main findings, we perceived that there is a lack (or even an absence) of usability evaluation or user studies to validate the proposed models. Although all articles are related to the topic of usability, none of them clearly defines it, and only a few actually employ usability design principles and/or guidelines.
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| 9. |
- Barber, I., et al.
(författare)
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Effects of experimental Schistocephalus solidus infections on growth, morphology and sexual development of female three-spined sticklebacks, Gasterosteus aculeatus
- 2003
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Ingår i: Parasitology. - 0031-1820 .- 1469-8161. ; 126, s. 359-367
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Tidskriftsartikel (refereegranskat)abstract
- The use of naturally infected hosts in studies attempting to identify parasite-induced changes in host biology is problematical because it does not eliminate the possibility that infection may be a consequence, rather than a cause, of host trait variation. In addition, uncontrolled concomitant infections may confound results. In this study we experimentally infected individual laboratory-bred female three-spined sticklebacks Gasterosteus aculeatus L. with the pseudophyllidean cestode Schistocephalus solidus [Muller], and compared the morphology and growth patterns of infected females with sham-exposed controls over a 16-week period. Fish were fed a ration of 8% body weight per day. Non-invasive image analysis techniques allowed the growth of individual plerocercoids to be tracked in vivo throughout the course of infection, and patterns of host and parasite growth were determined. Females that developed infections diverged morphometrically from unexposed control females and exposed-uninfected females at 6 weeks post-infection, with the width of the body at the pectoral fins giving the earliest indication of infection success. When including the plerocercoid, infected females gained weight more quickly than controls, but when plerocercoid weight was removed this trend was reversed. There was no effect of infection on the increase in fish length. Plerocercoids grew at different rates in individual hosts, and exhibited measurable sustained weight increases of up to 10% per day. Final estimates of plerocercoid weight from morphometric analysis prior to autopsy were accurate to within +/-17% of actual plerocercoid weight. At autopsy, infected female sticklebacks had significantly lower perivisceral fat reserves but had developed significantly larger ovaries than controls. The results are discussed in relation to previous studies examining natural infections, and the value of utilizing experimental infections to examine ecological aspects of host-parasite interactions is discussed.
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| 10. |
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