The aim of the master's thesis "Analysis of Selected Payment Protocols" is overview of used payment. The first part is concentrated on data security, the second is dedicated to payment protocols, their characteristics, used technology and security elements. The third part is dedicated to verification and simulation tools. Comparison of particular payment protocols and of particular verification tools is part of this work too. Experimental part of the thesis is focused on formalization and verification of the payment protocol Visa 3-D Secure, of the protocol NetBill and on formalization of two subprotocols of SET.

The aim of this Master thesis is to describe why and how public librariesuse the social networks Facebook and Twitter. The focus is to study whatbrought about their use, how the work is carried out, ideas and objectivesbehind the use and what libraries actually convey on the networks. Themethodology is twofold: semi-structured interviews with responsiblepersonnel at four Swedish public libraries, and an ethnographic contentanalysis of four months of the libraries' status updates and tweets onFacebook and Twitter. The theoretical framework consists of a model forthe roles of the public library in society, and of discourses about thepublic library in media.Results indicate that social networks are used to market, make accessibleand inform of the library's resources and services. Furthermore, networksare used to communicate/interact with followers and to inspire people toread. We also detect a tutoring trait. Libraries also view social networksas a meeting place. What libraries do on the networks can be seen as anonline interpretation of traditional library goals. All four spaces from themodel for the new library – Inspiration, Learning, Meeting andPerformative – were represented in the objectives expressed in theinterviews. In what is conveyed on the networks focus lay on Inspirationand Meeting. Social networks also act as a place to market the physicallibrary. From a discourse perspective the study suggests that librariesexpress disidentification and demonstrate ability to remain open both todifferent media formats and different methods for library servicesdelivery. / Program: Bibliotekarie

Thesis (doctoral)--Universität, Duisburg, 2003. / Includes bibliographical references (p. 303-343).

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Phased array feeds (PAFs) are a promising new technology for astronomical radio telescopes. While PAFs have been used in other fields, the demanding sensitivity and calibration requirements in astronomy present unique new challenges. This dissertation presents some of the first astronomical PAF results demonstrating the lowest noise temperature and highest sensitivity at the time (66 Kelvin and 3.3 m^2/K, respectively), obtained using a narrowband (425 kHz bandwidth) prototype array of 19 linear co-polarized L-band dipoles mounted at the focus of the Green Bank 20 Meter Telescope at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia. Results include spectral line detection of hydroxyl (OH) sources W49N and W3OH, and some of the first radio camera images made using a PAF, including an image of the Cygnus X region. A novel array Y-factor technique for measuring the isotropic noise response of the array is shown along with experimental measurements for this PAF. Statistically optimal beamformers (Maximum SNR and MVDR) are used throughout the work. Radio-frequency interference (RFI) mitigation is demonstrated experimentally using spatial cancelation with the PAF. Improved RFI mitigation is achieved in the challenging cases of low interference-to-noise ratio (INR) and moving interference by combining subspace projection (SP) beamforming with a polynomial model to track a rank 1 subspace. Limiting factors in SP are investigated including sample estimation error, subspace smearing, noise bias, and spectral scooping; each of these factors is overcome with the polynomial model and prewhitening. Numerical optimization leads to the polynomial subspace projection (PSP) method, and least-squares fitting to the series of dominant eigenvectors over a series of short term integrations (STIs) leads to the eigenvector polynomial subspace projection (EPSP) method. Expressions for the gradient, Hessian, and Jacobian are given for use in numerical optimization. Results are given for simulated and experimental data, demonstrating deeper beampattern nulls by 6 to 30dB. To increase the system bandwidth toward the hundreds of MHz bandwidth required by astronomers for a fully science-ready instrument, an FPGA digital backend is introduced using a 64-input analog-to-digital converter running at 50 Msamp/sec and the ROACH processing board developed at the University of California, Berkeley. International efforts to develop digital back ends for large antenna arrays are considered, and a road map is proposed for development of a hardware correlator/beamformer at BYU using three ROACH boards communicating over 10 gigabit Ethernet.

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Does the individual really matter in the post-modern world, brimming with countless signs and signifiers? My main objective in this writing is to demonstrate how this happens in Verhoeven's films, exploring his central themes and subtext and doing what science fiction does: hold a mirror up to the contemporary world and critique it, asking whether our species' current trajectory is beneficial or hazardous.; Dutch director Paul Verhoeven is a polarizing figure. Although many of his American made films have received considerable praise and financial success, he has been lambasted on countless occasions for his gratuitous use of sex, violence, and contentious symbolism--1995s Showgirls was overwhelmingly dubbed the worst film of all time and 1997s Starship Troopers earned him a reputation as a fascist. Regardless of the controversy surrounding him, his science fiction films are a move beyond the conventions of the big blockbuster science fiction films of the 1980s (E.T. and the Star Wars trilogy are prime examples), revealing a deeper exploration of both sociopolitical issues and the human condition. Much like the novels of Philip K. Dick (and Verhoeven's 1990 film Total Recall--an adaptation of a Dick short story), Verhoeven's science fiction work explores worlds where paranoia is a constant and determining whether an individual maintains any liberty is regularly questionable. In this thesis I am basically exploring issues regarding power. Although I barely bring up the term power in it, I feel it is central. Power is an ambiguous term; are we discussing physical power, state power, objective power, subjective power, or any of the other possible manifestations of the word? The original Anglo-French version of power means "to be able," asking whether it is possible for one to do something. In relation to Verhoeven's science fiction work each demonstrates the limitations placed upon an individual's autonomy, asking are the protagonists capable of independent agency or rather just environmental constructs reflecting the myriad influences surrounding them.