79 research outputs found
Pulse width modulation (PWM) method for power components estimation under harmonic distortion conditions:A. G. Bakaoukas; K. Triantafyllos
No full textIn this paper a Pulse Width Modulation (PWM) based method for the measurements of both Active Power (AP) and Reactive Power (RP) under harmonic distortion conditions in power systems is proposed. The method takes advantage of the fact that frequencies present in a power line are of a specific fundamental frequency range (a range centred on the 50Hz or 60Hz) and that in case of the presence of harmonics the frequencies of those dominating in the power line spectrum can be specified on the basis of the fundamental. In contrast to a number of existing methods a time delay or shifting of the input signal is not required by the method presented and the time delay by π/2 of the Current signal with respect to the Voltage signal required by many of the existing measurement techniques, does not apply in the case of the PWM method as well. Another advantage of the presented method is that the fundamental frequency of the power line is considered as an unknown parameter simultaneously estimated with the signal's spectrum, so the method becomes insensitive to fundamental power line frequency changes. Complex computations that include multiplication of the Voltage and Current sample values by trigonometric functions are also avoided
An all-optical soliton FFT computational arrangement in the 3NLSE-domain
Full text linkIn this paper an all-optical soliton method for calculating the Fast Fourier Transform (FFT) algorithm is presented. The method comes as an extension of the calculation methods (soliton gates) as they become possible in the cubic non-linear Schrödinger equation (3NLSE) domain, and provides a further proof of the computational abilities of the scheme. The method involves collisions entirely between first order solitons in optical fibers whose propagation evolution is described by the 3NLSE. The main building block of the arrangement is the half-adder processor. Expanding around the half-adder processor, the “butterfly” calculation process is demonstrated using first order solitons, leading eventually to the realisation of an equivalent to a full Radix-2 FFT calculation algorithm
A Novel Spatial Domain Semi-fragile Steganography Algorithm and Authentication Method
No full textIn this paper, a novel spatial domain semi-fragile steganography method is presented that takes full advantage of the Least Significant Bit (LSB) embedding approach and transforms it into a true three-layer data embedding technique. The method also takes advantage of the Parity Check method for error detection, and considerably expands and improves upon the proposed parity check approach to steganography. After application of the technique proposed in this paper, a stego-image is produced which contains a minimum of embedding artefacts due to the additional data embedded into the existing image data and which are not easily detectable by statistical analysis driven steganalysis tools designed to operate at the spatial domain. As a result, utilisation of embedding artefacts from steganalysis algorithms realising both Visual and Statistical attacks in the spatial domain becomes subject to optimum or as close to optimum as possible embedding parameters, gradually impossible
Algorithms and approaches for procedural terrain generation
No full textThis paper aims to discuss existing approaches to procedural terrain generation for games. This will include both the many functions that are used to generate ‘noise’ (something that has proved exceptionally useful in procedural terrain and texture synthesis) as well as some advanced procedural content generation techniques. The paper concludes with a summary of the discussed material while attempting to highlight areas for future research
The Two Separate Optical Fibres Approach in Computing with 3NLSE–Domain Optical Solitons
No full textComputing with first and higher order solitons in non-linear optical media
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Examining brain activity while playing computer games
Full text linkIn this paper, an investigation and its results towards brain activity pattern recognition while playing computer games using a non-invasive brain-computer interface (BCI) device is presented. The main aim of the study was to analyse data recorded while participants were engaged in playing popular computer games. The major contribution of the analysis presented is the confirmation of the hypothesis that there is a connection between activities in the brain and the different categories of computer games. Three different popular computer games were used, and the recordings took place under the conditions imposed by two different environments, a noisy one (a typical open-access university computer lab) and a quiet one (a typical controlled-access university computer lab under controlled environmental parameters). Initial results, obtained after analysing the raw electro-encephalography (EEG) recorded data, suggest that there might be a significant connection between the type of activity taking place in the human brain and the type of computer game a player is engaging with
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