Coherent detection employing multilevel modulation formats has become one of the most promising technologies for next generation high speed transmission systems due to the high power and spectral efficiencies. Using the powerful digital signal processing (DSP), coherent optical receivers allow the significant equalization of chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN) and nonlinear effects in the electrical domain. Recently, the realizations of these DSP algorithms for mitigating the channel distortions in the coherent transmission systems are the most attractive investigations. The CD equalization can be performed by the digital filters developed in the time and the frequency domain, which can suppress the fiber dispersion effectively. The PMD compensation is usually performed in the time domain with the adaptive least mean square (LMS) and constant modulus algorithms (CMA) equalization. Feed-forward and feed-back carrier phase estimation (CPE) algorithms are employed to mitigate the phase noise (PN) from the transmitter (TX) and the local oscillator (LO) lasers. The fiber nonlinearities are compensated by using the digital backward propagation methods based on solving the nonlinear Schrödinger (NLS) equation and the Manakov equation. In this dissertation, we present a comparative analysis of three digital filters for chromatic dispersion compensation, a comparative evaluation of different carrier phase estimation methods considering digital equalization enhanced phase noise (EEPN) and a brief discussion for PMD adaptive equalization. To implement these investigations, a 112-Gbit/s non-return-to-zero polarization division multiplexed quadrature phase shift keying (NRZ-PDM-QPSK) coherent transmission system with post-compensation of dispersion is realized in the VPI simulation platform. In the coherent transmission system, these CD equalizers have been compared by evaluating their applicability for different fiber lengths, their usability for dispersion perturbations and their computational complexity. The carrier phase estimation using the one-tap normalized LMS (NLMS) filter, the differential detection, the block-average (BA) algorithm and the Viterbi-Viterbi (VV) algorithm is evaluated, and the analytical predictions are compared to the numerical simulations. Meanwhile, the phase noise mitigation using the radio frequency (RF) pilot tone is also investigated in a 56-Gbit/s NRZ single polarization QPSK (NRZ-SP-QPSK) coherent transmission system with post-compensation of chromatic dispersion. Besides, a 56-Gbit/s NRZ-SP-QPSK coherent transmission system with CD pre-distortion is also implemented to analyze the influence of equalization enhanced phase noise in more detail. / QC 20120528

This research mainly develops a new z-position measurement based on the chromatic aberration effect. An objective-type dark-field illumination scheme is built to produce diascopic chromatic aberration light, and aimed to enhance the signal-to-noise ratio. The xenon lamp is adapted to create white light with continuous spectrum, besides, lens with low Abbe number is needed to extend the degree of chromatic aberration, so lens made of PMMA is as a chromatic aberration component. In the proposed system, the depths of samples in micro-channel is illuminated by the dispersed light and scatter the optical signals, which are captured by a low numerical aperture (N.A.) objective lens. After the simple normalization, the intensity ratio of two selected wavelengths 450 nm (blue light) and 670 nm (red light) from the scattered spectrum becomes a reliable index for the depth information of the detecting objects. By means of establishing the relationship between depth and intensity ratio, every object flowing through diagnosed spot is able to be determined the depth level by cross-referencing the database. By using spectrometer as detector, delicate moving components for light filtering or electrical stage for light scanning can be excluded for high-speed z-position detection. Furthermore, in order to identify the depth level of sample with high flowing rate, avalanche photodiodes are adapted to achieve rapid detection. The experimental results show that the relationship between depth and intensity ratio is a parabola curve, but in this research, the region which tends to behavior linearly is adapted. The proposed system provides a linear detection range of ¡Ó15 £gm for particles with a diameter of 20 £gm. The lens with high Abbe number only obtains ¡Ó10 £gm with linear detection range though, the resolution for size is better than PMMA. The BK7 lens is capable to discriminate the depth change of 2 £gm micro-beads, note that there is no limitation of depth discrimination in this system, because of the measurement is achieved by cross-referencing the linear line. The use of UV-Vis-NIR spectrometer enable this system to analyze the depths of the samples in flow rate 0.5 mm/s. To gain the higher performance, the two avalanche photodiodes are utilized, and the short(CWL=450 nm, ¡Ó20 nm) and long(CWL=650 nm, ¡Ó20 nm) band pass filter are also equipped to represent enhancements of blue and red ray. The effective detection range extends to ¡Ó25 £gm and has high linearity(R square=0.99285) after the optimization of light stop. In high flowing rate detection, this system is able to identify the depth of sample when the flow velocity is 4.167 mm/s, the calculated throughput is 126 particles/s. It also successfully analyzes the depth of flowing human erythrocytes under the flow velocity is 2.778 mm/s, the velocity which the developed system is capable to analyze is about 5-8 folds to the conventional micro-PIV system. With this novel and simple approach, there will be the quantified information from z-direction of flowing body for bio-analysis, and also benefits estimating the performance of micro structure or device in the microfluidic chip, also the analysis of flow field. Except for dynamical detection, this system also be capable to apply in a open and static situation, such as cell or tissue proliferation assay.

Photonic crystal fibers (PCFs) are divided into two different kinds of fibers. The first one, index-guiding PCF, guides light by total internal reflection between a solid core and a cladding region with multiple air-holes. On the other hand, the second one uses a perfectly periodic structure exhibiting a photonic band-gap (PBG) effect at the operating wavelength to guide light in a low index core-region. A compact 2D-FDTD method based on finite-difference time-domain method is formulated and is effectively applied to analysis PCFs and PBGFs. We study the propagation features of fundamental mode and the fundamental characteristics such as effective index, modal-field diameter and chromatic dispersion in index-guiding PCFs. By optimizing the air-hole diameters and the hole-to-hole spacing of index-guiding PCFs, both the dispersion and the dispersion slope can be controlled in a wide wavelength range. We also investigate the propagation features of fundamental mode and band-gap effect of PBGFs.

This study aims to examine the ways in which English composer Edward Elgar (1857–1934) expanded common-practice tonality; it shows how Elgar employed harmonic structures and syntax in an innovative manner through specific extended-tonal techniques such as the use of chromatic-third relations (both harmonically and as a tonal plan), harmonic substitutions, and local ambiguous sonorities that at times lead to tonal ambiguity. The system that Elgar expanded upon has been called “Classical diatonic tonality”, which was extended when late nineteenth-century composers such as Elgar infused their music with chromaticism. Through an investigation of Elgar’s extended tonal techniques one can come to a better appreciation of his late nineteenth-century harmonic vocabulary. It has been well documented that Elgar modeled his music after that of Wagner and his Germanic contemporaries (from Mendelssohn to Brahms), so that the Elgarian tonal language is one possible projection of a post-Wagnerian extended-tonal discourse. The discussion presented here will survey those parts of Elgar’s tonal language that he learned from his Germanic contemporaries, thereby establishing the context for his own unique chromatic compositional style. This study of Elgar’s work therefore further represents a study of the broader impact of post-Wagnerian chromaticism on late nineteenth-century English extended tonality.

The entropy of a graph is a functional depending both on the graph itself and on a probability distribution on its vertex set. This graph functional originated from the problem of source coding in information theory and was introduced by J. K\"{o}rner in 1973. Although the notion of graph entropy has its roots in information theory, it was proved to be closely related to some classical and frequently studied graph theoretic concepts. For example, it provides an equivalent definition for a graph to be perfect and it can also be applied to obtain lower bounds in graph covering problems. In this thesis, we review and investigate three equivalent definitions of graph entropy and its basic properties. Minimum entropy colouring of a graph was proposed by N. Alon in 1996. We study minimum entropy colouring and its relation to graph entropy. We also discuss the relationship between the entropy and the fractional chromatic number of a graph which was already established in the literature. A graph $G$ is called \emph{symmetric with respect to a functional $F_G(P)$} defined on the set of all the probability distributions on its vertex set if the distribution $P^*$ maximizing $F_G(P)$ is uniform on $V(G)$. Using the combinatorial definition of the entropy of a graph in terms of its vertex packing polytope and the relationship between the graph entropy and fractional chromatic number, we prove that vertex transitive graphs are symmetric with respect to graph entropy. Furthermore, we show that a bipartite graph is symmetric with respect to graph entropy if and only if it has a perfect matching. As a generalization of this result, we characterize some classes of symmetric perfect graphs with respect to graph entropy. Finally, we prove that the line graph of every bridgeless cubic graph is symmetric with respect to graph entropy.

Σκοπός αυτής της διπλωματικής εργασίας είναι να παρουσιαστούν μερικές από τις πιο αξιοσημείωτες τεχνικές για την Ισοστάθμιση των Χρωματικών Αποκλίσεων σε ψηφιακή φωτογραφία. Αρχικά δίνονται κάποια γενικά στοιχεία για την ψηφιακή φωτογραφία, τα χρωματικά μοντέλα και συγκεκριμένα το μοντέλο RGB, την ψηφιακή καταγραφή της εικόνας καθώς και οι στοιχειώδεις λειτουργίες της ανθρώπινης όρασης. Στο δεύτερο κεφάλαιο αναλύονται οι βασικές έννοιες της χρωματικής απόκλισης και παραθέτονται με ορισμούς και παραδείγματα τα δυο βασικά είδη χρωματικών αποκλίσεων που είναι η αξονική χρωματική απόκλιση (longitudinal or axial aberration) και η πλευρική χρωματική απόκλιση (transverse or lateral aberration). Το τρίτο κεφάλαιο είναι μια αναλυτική περιγραφή τριών μεθόδων ισοστάθμισης/περιορισμού των χρωματικών αποκλίσεων. Δίνεται η θεωρητική ανάλυση κάθε μιας, η περιγραφή της πειραματικής διαδικασίας που ακολουθείται καθώς επίσης και τα συμπεράσματα που προκύπτουν από την εφαρμογή τους. Τέλος, στο τέταρτο κεφάλαιο δίνονται δυο διαφορετικοί τύποι σχεδιασμού φακού Gauss, που αποβάλλουν αποτελεσματικά την αρχική χρωματική παρέκκλιση χρησιμοποιώντας έναν αποδοτικό γενετικό αλγόριθμο (GA). / Aim of this Diploma Thesis Project is to present the most remarkable techniques of the Compensation of Chromatic Aberrations appeared in digital images. Initially are given certain general elements for the digital photograph, the chromatic models and especially the RGB model, the digital imaging process and the elementary operations of the human sight system. In the second chapter the basic significations of chromatic aberrations are analysed. Also, definitions and examples support the two basic types of chromatic distortions that are the longitudinal or axial aberrations and the transverse or lateral aberrations. The third chapter is a complete description of three methods of the compensation of chromatic distortions. It is given the theoretical analysis for each one, the full description of the experimental process that is followed and the conclusions that result from their application. Finally, in the last chapter, two different types of Gauss lens design, which effectively eliminate primary chromatic aberration, are presented using an efficient genetic algorithm (GA).

In the Rio Grande do Sul State, grape production is an already consolidated activity of significant socio-economic importance, accounting for about 90% of national production of grapes, wines and derivatives. In this sense, wine is an important product because of the added values transferred to the wineries and grape growers. There are five major wine regions within Rio Grande do Sul: Serra do Nordeste, Campanha, Serra do Sudeste, Central and Campos de Cima da Serra. Cabernet Sauvignon is the State's most important Vitis vinifera variety. The wine of this variety is world famous for its varietal character, intense color, richness in tannins and for its complexity of aroma and bouquet. Color is a key indicator of quality wines. It contributes to achieving the highest ratings and effectively the highest prices, and is directly related to quality of the raw material used. The objective methods of color evaluation are the fastest and, moreover, are replicable and not subject to subjective errors, so are of fundamental importance for the wine industry. The samples of red wines for this study, from the five wine regions of Rio Grande do Sul, were obtained in collaboration with the Instituto Brasileiro do Vinho (IBRAVIN) and analyzed at the Departamento de Tecnologia e Ciência de Alimentos of the Universidade Federal de Santa Maria. The following chromatic characteristics were analyzed: CIEL*a*b coordinates *L, *a and *b, cylindrical coordinates H* (hue angle) and C* (chroma), color intensity, hue and percentages of yellow, red and blue. Physicochemical parameters alcohol content, total acidity, pH, total phenolics content and anthocyanins were also determined. The wines from the Central region had the highest values of hue angle H* and the highest average of lightness. Samples from the Campanha region were characterized by the lowest average of hue. The wines from the Serra do Nordeste region were those with the highest average of croma, anthocyanins and total phenolics content. All wines were in accordance with Brazilian legislation for total acidity. However, pH values were high (near 4.0), which favors the development of bacteria. By the analysis of the results obtained in the chromatic and physical-chemical properties of the samples, it was possible to establish a comparison between Cabernet Sauvignon wines produced in Rio Grande do Sul, in different seasons and different wine regions, to support the quest for quality improvement in production of fine wines in the state. / No Estado do Rio Grande do Sul a produção de uvas é uma atividade já consolidada, de significativa importância socioeconômica, responsável por cerca de 90% da produção nacional de uvas, vinhos e derivados. Neste sentido, o vinho é um importante produto devido ao valor agregado que transfere para as vinícolas e para os produtores de uvas. São cinco as principais regiões vitivinícolas do Rio Grande do Sul: Serra do Nordeste, Campanha, Serra do Sudeste, Região Central e Campos de Cima da Serra. A cultivar Cabernet Sauvignon é a principal variedade Vitis vinifera do Estado. O vinho desta casta é mundialmente conhecido pelo seu caráter varietal, com intensa coloração, riqueza em taninos e complexidade de aroma e buquê. A cor compõe um dos principais indicadores da qualidade de vinhos, além de colaborar para alcançar as melhores classificações e efetivamente os maiores preços, relacionando-se diretamente com a qualidade da matéria-prima. Os métodos objetivos de avaliação da cor são os mais rápidos e, além disso, reproduzíveis e não sujeitos a erros subjetivos, logo são de fundamental importância para a indústria vinícola. As amostras de vinhos tintos Cabernet Sauvignon para este trabalho, provenientes das cinco regiões vitivinícolas do Rio Grande do Sul, foram obtidas com a colaboração do Instituto Brasileiro do Vinho (IBRAVIN) e analisadas no Departamento de Tecnologia e Ciência de Alimentos da Universidade Federal de Santa Maria. Foram analisadas as características cromáticas através das coordenadas cromáticas L*, a* e b* do Espaço CIE L*a*b*, das coordenadas cilíndricas H* (ângulo de tonalidade) e C* (Croma), bem como a quantificação dos índices de intensidade de cor, tonalidade e os percentuais das componentes amarela, vermelha e azul. Também foram determinados os parâmetros físico-químicos graduação alcoólica, acidez total, pH, conteúdo de antocianinas e compostos fenólicos totais. Os vinhos da Região Central apresentaram os maiores valores do ângulo de tonalidade H* e a maior luminosidade média. As amostras da Região da Campanha caracterizaram-se pela menor média de tonalidade. Já os vinhos da Região da Serra do Nordeste foram os que apresentaram as maiores médias de Croma, a maior média de antocianinas totais e também a maior média de índice de polifenóis totais. Quanto à acidez total, todos os vinhos analisados estavam em conformidade com a legislação brasileira, porém os valores de pH se apresentaram elevados (próximos de 4,0), situação que favorece o desenvolvimento de bactérias. Portanto, através dos resultados obtidos nas análises cromáticas e físico-químicas das amostras, foi possível estabelecer um comparativo entre vinhos Cabernet Sauvignon produzidos no Rio Grande do Sul, de diferentes safras e diferentes regiões vitivinícolas, no sentido de subsidiar a busca pelo aprimoramento da qualidade na produção de vinhos finos no estado.

[pt] Neste trabalho, uma análise do fenômeno de mistura de quatro ondas (FWM) em sistemas ópticos multicanais é apresentada. Inicialmente, uma série de simulações determina as limitações impostas aos sistemas ópticos, sendo adotado um nível máximo de crosstalk permitido. Em seguida, os diversos parâmetros que influenciaram a eficiência da geração de FWM são estudados detalhadamente, com resultados apresentados em forma de gráficos. Nestes últimos, o nível de FWM obtido é especificado em função da potência de entrada por canal, comprimento do enlace, número de canais, presença de amplificadores, número de amplificadores e dispersão cromática da fibra utilizada. Um breve estudo discute a deterioração da qualidade do serviço, causada pro FWM, em redes ópticas. O trabalho se encerra com algumas aplicações que utilizam, de forma favorável, o fenômeno de FWM. / [en] This work adresses the four-wave mixing (FWM) issue in optical multichannel systems. First, some simulations are carried out for specifying which are the optical system limitations coping with a maximum allowed crosstalk level. Next, the different parameters affecting the FWM are throughly studied, with these last pertinent results being graphicallly presented. In these, the obtained FWM levels are specified as a function of the channel input power, link span, channel rumber, presence of amplifiers, number of amplifiers and fiber chromatic dispersion. A concise discussion, concerning the quality of service deterioration on optical networks, due to FWM, is also presented. The work is finally closed by presenting some applications that favorably use the FWM phenomena.

The present master thesis compares die theories of colors created by Johann Wolfgang von Goethe and Rudolf Steiner, who both created their individual theory as a reaction regarding another one published approximately a century prior to them. The thesis presents their theories and compares them on the basis of a certain set of categories. Their circumstances of origin, contemporaneous usage, interdisciplinarity and creation of the chromatic circle as an explanatory tool are defined and discussed. Furthermore a description of noticeable differences and similarities is added and the author points out the possible influences of the chromatic theories towards other poetical, philosophical or paedagogical works of the respetive creator.

Sob o ponto de vista de durabilidade, os concretos cromáticos merecem atenção especial, não apenas pelas suas propriedades físicas e químicas, mas principalmente pela sua utilização como elemento arquitetônico, o qual permite a confecção de elementos estruturais aparentes, deixando-os assim mais suscetíveis à ação destrutiva das intempéries. Poucos são os trabalhos publicados que apresentam o comportamento deste material ao longo do tempo e em sua maioria, os pesquisadores avaliam a resistência à compressão como forma de parâmetro de sua qualidade. Neste contexto, o objetivo do trabalho é analisar a influência da adição de pigmentos em algumas propriedades de durabilidade e na cromacidade de concretos de cimento Portland branco. Para isso, montou-se um programa experimental composto por 21 traços diferentes, onde foram realizadas combinações entre 2 tipos de pigmentos inorgânicos de bases químicas diferentes, adicionados em 4 teores (0, 3, 6 e 10%) e com 3 relações a/c (0,40; 0,55 e 0,70). Para cada traço foram moldados 17 cp's os quais se destinam aos ensaios de resistência à compressão, penetração acelerada de cloretos, carbonatação, absorção de água por capilaridade e cromacidade. Todos os resultados experimentais, foram modelados estatisticamente. Os modelos obtidos nos ensaios mostram que o teor de adição e o tipo de pigmento não exercem influência significativa sobre a durabilidade do concreto. O teor de adição, apesar de significativo, pouco alterou a resistência à compressão; houve um acréscimo de cerca de 2 e 5% para os pigmentos verde e vermelho, respectivamente. Quanto à cromacidade; com a adição de 6% do pigmento vermelho o concreto já atinge tonalidades próximas a cor original do pigmento, ao passo que os concretos com pigmentos verde é necessária a adição de 10% para se obter tonalidades mais escuras e mais próximas a cor do pigmento. / Considering the durability of chromatic concrete, one can see it deserves special attention, not only because of its physical and chemical properties, but manly for its use as an architectonic element, which allows the making of apparent structural elements more susceptible to weather destructions. There are few publications reporting the situation of this material towards time, since most of the researchers evaluate the resistance of chromatic concrete to compression as a parameter to its quality. Within this context, the present study aims to analyze the influence of the addition of pigments into some durability proprieties and into the chromaticity of the white Portland cement concrete. An experimental program, with 21 different traces, was designed; combinations between 2 types of inorganic pigments from different chemical bases added with 4 contents (0, 3, 6 and 10%) and with 3 relations a/c (0,40; 0,55 e 0,70) were conducted. For each content, 17 cp’s were molded to the trials of: resistance to compression, chlorite accelerated penetration, carbonation, water absorption due to capillarity, and chromaticity. All the experimental results were statistically molded. The models obtained in the trials show that the addition content and the type of pigment do not exert significant influence upon the durability of concrete. The addition content, although significant, demonstrated a little difference in terms of resistance to compression; there was an increase around 2 and 5% for the green and red pigments, respectively. For chromaticity, the 6% addition of red pigment makes the concrete color similar to the original pigment, whereas the green pigment requires a 10% addition in order to obtain a darker and more similar color to the original green.