Žiniatinklio srautų technologija neseniai pradėjo augti, tačiau ji sparčiai išplito ir tapo dažnai sutinkama internetiniuose puslapiuose. Dabar yra trys pagrindiniai naudojimi žiniatinklio srauto formatai ATOM 1.0, RSS 2.0 ir RSS 1.0. Šiame darbe yra parašyta nauja žiniatinklio srautų specifikacija, kuri sujungia visus ATOM 1.0, RSS 2.0 ir RSS 1.0 formatus ir pridedami atitinkamai nauji elementai. Kad tai padaryti buvi išanalizuota ATOM 1.0, RSS 2.0 ir RSS 1.0 formatų architektūra. Universalaus žiniatinklio srautų architektūra realizuota sukurtame konvertavimo į universalų žiniatinklio srauto metode, kuris gali būti naudojamas projektuose. Sukurtas metodas verčia ATOM 1.0, RSS 2.0 ir RSS 1.0 formatų dokumentus į šiame darbe aprašytą universalų žiniatinklio srauto formatą ir normalizuoja jį. Rezultatai, gauti po ATOM 1.0, RSS 2.0 ir RSS 1.0 dokumentų konvertavimo į universalų žiniatinklio srauto formatą yra palyginti ir padarytos išvados. / Feed technology has only just started growing, but it become very popular and can meet in most web pages. There is at least three major competing feed formats in ATOM 1.0, RSS 2.0 and RSS 1.0 . In this work is written new feed format specification, which joins all ATOM 1.0, RSS 2.0 and RSS 1.0 formats and includes new ones elements. To do this has been analysed ATOM 1.0, RSS 2.0 and RSS 1.0 architekture. Universal feed architekture realized in created universal feed parser method, which can be included in projects. Craeted method replaces ATOM 1.0, RSS 2.0 and RSS 1.0 documents into universal feed document and normalize them. Results got after converting ATOM 1.0, RSS 2.0 and RSS 1.0 feeds into universal feed document is compared and made conclusion.

Universiẗat, Diss., 2000--Kaiserslautern.

Techn. Universiẗat, Diss., 2004--Kaiserslautern.

In this thesis we study device-independent quantum key distribution based on energy-time entanglement. This is a method for cryptography that promises not only perfect secrecy, but also to be a practical method for quantum key distribution thanks to the reduced complexity when compared to other quantum key distribution protocols. However, there still exist a number of loopholes that must be understood and eliminated in order to rule out eavesdroppers. We study several relevant loopholes and show how they can be used to break the security of energy-time entangled systems. Attack strategies are reviewed as well as their countermeasures, and we show how full security can be re-established. Quantum key distribution is in part based on the profound no-cloning theorem, which prevents physical states to be copied at a microscopic level. This important property of quantum mechanics can be seen as Nature's own copy-protection, and can also be used to create a currency based on quantummechanics, i.e., quantum money. Here, the traditional copy-protection mechanisms of traditional coins and banknotes can be abandoned in favor of the laws of quantum physics. Previously, quantum money assumes a traditional hierarchy where a central, trusted bank controls the economy. We show how quantum money together with a blockchain allows for Quantum Bitcoin, a novel hybrid currency that promises fast transactions, extensive scalability, and full anonymity. / En viktig konsekvens av kvantmekaniken är att okända kvanttillstånd inte kan klonas. Denna insikt har gett upphov till kvantkryptering, en metod för två parter att med perfekt säkerhet kommunicera hemligheter. Ett komplett bevis för denna säkerhet har dock låtit vänta på sig eftersom en attackerare i hemlighet kan manipulera utrustningen så att den läcker information. Som ett svar på detta utvecklades apparatsoberoende kvantkryptering som i teorin är immun mot sådana attacker. Apparatsoberoende kvantkryptering har en mycket högre grad av säkerhet än vanlig kvantkryptering, men det finns fortfarande ett par luckor som en attackerare kan utnyttja. Dessa kryphål har tidigare inte tagits på allvar, men denna avhandling visar hur även små svagheter i säkerhetsmodellen läcker information till en attackerare. Vi demonstrerar en praktisk attack där attackeraren aldrig upptäcks trots att denne helt kontrollerar systemet. Vi visar också hur kryphålen kan förhindras med starkare säkerhetsbevis. En annan tillämpning av kvantmekanikens förbud mot kloning är pengar som använder detta naturens egna kopieringsskydd. Dessa kvantpengar har helt andra egenskaper än vanliga mynt, sedlar eller digitala banköverföringar. Vi visar hur man kan kombinera kvantpengar med en blockkedja, och man får då man en slags "kvant-Bitcoin". Detta nya betalningsmedel har fördelar över alla andra betalsystem, men nackdelen är att det krävs en kvantdator.

This thesis describes the work performed at the Quantum Optics lab at UNAM,Mexico City. Third order spontaneous parametric down conversion (TOSPDC) isa quantum optical process where an incoming photon is annihilated and generatesthree quantum entangled photons, so called photon triplets, under energy and mo-mentum conservation. This TOSPDC process was experimentally realized using afused silica optical fiber as nonlinear source. The spectra of the emitted signal weremeasured and coincidence counts measurements were performed in order to verifythe generation of these triplets. An average of 0.8 triplets per second were detected,which is the first sign of a realized TOSPDC process to our knowledge. At thispoint, the signal was too low for any spectra to be recorded. There is a lot of roomfor improvements, especially regarding the equipment used due to the heavy signalloss throughout the experimental setup, and more experiments will be performed toproperly verify the production and entanglement of the triplet photons.

Quantification of spectral data is of great interest in many fields of science, since it can provide further insight into other properties of an object. However, traditional cameras are usually made to image the world in a similar fashion as to how we see it, wherefore they are usually not fit to record nor measure further spectral information. To get a better insight into the spectral properties of an object, a hyperspectral camera might be of use, since those can often identify and measure hundreds of different spectral bands. In this study we look at the construction and further development of an existing design of a push broom hyperspectral imaging system, built with optics for a fraction of the cost of commercial ones. With developed software and objects at hand a spectral calibration was performed, showing a possible spectral range of 184(2)-918(11) nm, but the use of the whole spectral range was however not possible due to limitations in the transmissivity of the lenses below 350 nm. A shift of the spectral range towards longer wavelengths is proposed, which would give further insight into the near infrared spectrum without any information losses. It was found that the spectral calibration of the imager was the main limiting factor of the system, since inaccuracies up to ±11 nm were identified, while the resolution has been found to be 1.4 nm in previous studies, proving that better calibrations are of essence. In good operating conditions, the resolution in the angle of view of the imager was found to be 0.55 mdeg. If the measurement conditions are not as good, or if such kind of spatial resolution is not required, a camera with a smaller detector size and larger pixels could be used to lower the cost of the system without a deterioration in image quality, since the uncertainties in the calibrations and measurement conditions were found to be the limiting factor.

In this thesis, periodic structures with higher symmetries symmetries are discussed. The main focus of the thesis is on twist symmetries. Importantly, the attractive properties of twist symmetries for the control of electromagnetic wave propagation are demonstrated. Furthermore, the additional degree of freedom offered by twist symmetries is used to design two microwave devices. A structure is twist-symmetric if its periodicity can be described by the geometrical operation consisting of a translation and a rotation around an axis. In this thesis, it is demonstrated that there are no stop-bands between the first q modes in the Brillouin diagram of a twist-symmetric structure, where q is the symmetry order. The importance of the symmetry to the absence or presence of stop-bands is illustrated by studying structures where the symmetry is gradually broken. Furthermore, it is demonstrated that a twist-symmetric structure can produce a higher and less dispersive effective refractive index, compared to a conventional periodic structure. These characteristics are attractive for the design of microwave devices. To provide insight into the physics of twist symmetry, a mode matching formulation is derived to analyze twist-symmetric coaxial transmission lines. The formulation is used to highlight the importance of higher order coupling on the response in structures with varying order of the twist symmetry.  In this thesis, we also discuss another type of symmetry; polar glide symmetry. A periodic structure possesses a polar glide symmetry if its periodicity can be described by the geometrical operation consisting of a translation and a reflection in a cylindrical surface. It is demonstrated that there is no stop-band between the first two modes in a polar glide structure, which is similar to what has been reported for Cartesian glide symmetry previously. Furthermore, twist symmetry and polar glide symmetry is combined into twisted polar glide symmetry. The effect of this combination on the stop-band between the second and third modes is demonstrated. It is concluded that this type of symmetry finds application in filter design. Finally, the additional design freedom offered by twist symmetry is used to produce two microwave components. A reconfigurable phase shifter is designed, where the phase delay in the phase shifter depends on the order of the twist symmetry. Furthermore, a flat lens is designed to transform a spherical wave into a quasi-planar wave. The focusing properties of the lens is obtained by locally varying the order of the symmetry throughout the lens aperture. / I denna avhandling diskuteras periodiska strukturer med högre symmetrier. Huvudfokus av avhandlingen är skruvsymmetrier. Vi visar de attraktiva egenskaperna av skruvsymmetrier för kontrollen av elektromagnetiska vågor. Dessutom används den extra designfriheten från skruvsymmetrier för att designa två mikrovågskomponenter. En struktur är skruvsymmetrisk om dess period kan beskrivas av en geometriska operation bestående av en translation och en rotation runt en axel. I denna avhandling visar vi att det inte finns några bandgap mellan de första q moderna i Brillouindiagrammet för en skruvsymmetrisk struktur, där q är symmetriordningern. Betydelsen av symmetri för frånvaron och närvaron av bandgap illustreras genom att studera strukturer där symmetrin gradvis bryts. Vidare visar vi att en skruvsymmetrisk struktur kan producera ett högre och mindre dispersivt effektivt refraktivt index jämfört med en vanlig periodisk struktur. Dessa egenskaper är attraktiva i designen av mikrovågskomponenter. För att ge insikt i fysiken bakom skruvsymmetrier tas en modmatchningsformulering fram för att studera skruvsymmetriska koaxiala transmissionsledare. Formuleringen används för att belysa vikten av högre ordnings vågkoppling för egenskaperena i strukturer med olika ordnings skruvsymmetri.  I denna avhandling diskuteras ytterliage en typ av högre symmetri; polär glidsymmetri. En struktur har en polär glidsymmetri om dess period kan beskrivas av en geometriska operation bestående av en translation och en spegling i en cylindrisk yta. Vi visar att det inte finns något bandgap mellan de två första moderna i en struktur med polär glidsymmetri, vilket också tidigare visats för Cartesisk glidsymmetri. Vidare kombinerar vi skruv- och polär glidsymmetri. Implikationerna av denna kombination på bandgapet mellan högre moder diskuteras. Vi kommer fram till att denna typ av kombinerad symmetri finner tillämpningar i filterdesign.  Slutligen används den extra designfriheten från skruvsymmetri för att designa två mikrovågskomponenter. En konfigurerbar fasskiftare designas, där fasskiftningen beror på symmetriordningen. Vidare designas en platt lins som omvandlar en sfärisk våg till en kvasiplan våg. Fokuseringsegenskaperna i linsen uppnås genom att lokalt variera symmetriordningen i linsens apertur. / <p>QC 20211103</p>

Calculation of number of photon pairs produced by type-I degenerate Spontaneous Parametric Down-Conversion inside a BBO crystal.

Today we are seeing exciting developments in the field of autonomous vehicles, on both software and hardware. Veoneer is a company making a contribution where research and manufacturing is being done on hardware and active safety. One of the most important aspects in this field is road safety, where understanding the behaviour of sensors used in vehicles is essential. From the point of view of safety, understanding how weather affects the sensors is necessary for a successful deployment. This study is a continuation of previous studies done at Veoneer, and regards how various adverse condition affect the performance of a short-range LiDAR and gives a thorough description of the involved physical processes. Data collected over a couple of months was analysed and compared to theoretical models in order to establish their validity. In addition, LiDAR measurement were done in a chamber where conditions could be varied in a controlled manner. Furthermore, analysis methods were used to transform the data into a form potentially more useful for use in machine learning algorithms to estimate the ability to classify conditions based on LiDAR signals. The used models showed mixed results, with some showing more agreement than others. Models regarding foggy conditions generally showed greater agreement with data than in other conditions, although some variation around the predictions did occur. In regards to the performance of the classification algorithms, there were als omixed results, where the sensitivity in fog was at most 96 % and the precision at most 64 %. This thesis also enables and suggests further research into the utility of short-range LiDAR both in the field of autonomous vehicle safety as well as in use of other fields such as meteorology.

Increasing global warming with droughts, forest fires and melting polar ice has forced the world to speed up the transition from fossil fuel to fossil free energy. A big part of it is the use of solar energy. To obtain solar thermal energy, different sorts of solar collectors have been developed. One of these are the parabolic solar collector, a trough which concentrates the sun rays onto a receiver tube, which in turn absorbs the thermal heat. Absolicon Solar Collector AB is a Swedish company developing a parabolic solar collector named T160. These collectors are optically verified in the end of the Absolicon production line to decide if they meet the expected criteria. The verification of the parabolic shape is of utmost importance for the performance of the trough while a shape error can cause the beam to hit the receiver tube in a sub-optimal angle or miss it completely. If this were to happen, all of the energy can not be extracted. Earlier research have developed different methods for finding slope errors, deviations in the normal angles, in the trough but does not investigate the connection between slope errors and the trough shape errors that might have caused the deviations. This report aims to develop an algorithm based on slope errors in a parabolic trough collector which identifies four predetermined common shape errors in the trough. Identifying shape errors help to quickly identify and correct systematic deviations. In addition, this work aims to implement a new acceptance criteria based on slope errors for the solar collectors to make sure they hold up to their standard. The algorithm should also be compatible with a new camera system being implemented in the optical verification at Absolicon. This is done by deriving mathematical expressions for the normal angles in the trough with respect to the shape errors. By using the Pinhole Camera Model, the Law of Reflection and geometric properties of the solar collector, it is possible to convert pixel coordinates of receiver tube edges in images to normal angles. The resulting deviation in normal angle compared to the ideal ones are analysed and fitted to the mathematically derived expression for the normal angles by a build in minimization method in the tool lmfit in Python which uses non-linear least squares to detect type shape errors. The acceptance criteria and compatibility with the new system is implemented and taken into account. The results show that the calculation of slope errors from the data is valid with an uncertainty of 0.82 mrad and expected differences in the acceptance criteria quality value is seen when dealing with solar collectors with different type shape errors. The type shape error algorithm finds the correct shape errors for noisy self-created data which shows that the method works. The results when testing on real collectors with forced shape errors show potential but is in need of further adjustments and more clean precise data to produce certain accurate results. The algorithm is a good start to create a tool for finding typical shape errors in parabolic solar collectors.