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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Aspectos reprodutivos e produtivos de carneiros da raça Morada Nova submetidos a níveis crescentes de suplementação concentrada / Reproductive and productive aspects of the breed sheep Morada Nova subjected to increasing levels of concentrate supplementation

Silva, Taciane Alves da January 2015 (has links)
SILVA, Taciane Alves da. Aspectos reprodutivos e produtivos de carneiros da raça Morada Nova submetidos a níveis crescentes de suplementação concentrada. 2015. 74 f. : Dissertação (Mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Zootecnia, Programa de Pós-Graduação em Zootecnia. Fortaleza-CE, 2015. / Submitted by Eric Santiago (erichhcl@gmail.com) on 2016-08-09T15:42:56Z No. of bitstreams: 1 2015_dis_tasilva.pdf: 1372727 bytes, checksum: c5aed07999861a6537d53a0a85389f2e (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-09T15:45:42Z (GMT) No. of bitstreams: 1 2015_dis_tasilva.pdf: 1372727 bytes, checksum: c5aed07999861a6537d53a0a85389f2e (MD5) / Made available in DSpace on 2016-08-09T15:45:42Z (GMT). No. of bitstreams: 1 2015_dis_tasilva.pdf: 1372727 bytes, checksum: c5aed07999861a6537d53a0a85389f2e (MD5) Previous issue date: 2015 / The study was conducted in order to evaluate the effects of different levels of concentrated supplementation on body weight, seminal parameters, testicular biometry measurements, protein profile of seminal plasma and protein profile of the Longissimus dorsi muscle of the breed of sheep Morada Nova. 22 seven months old sheep were used. The treatments consisted in different levels of concentrated (0%, 0.6%, 1.2% and 1.8% of the animals’ body weight based on dry matter). The animals were kept under a rotational grazing system, on Aruana grass (Panicum maximum). The semen samples were collected through electroejaculation at the end of the experiment, when the animals reached the age of 10 months. After slaughtering, the testicles and the muscle Longissimus dorsi were collected. The testicles were measured and the seminal and muscle proteins were analyzed through two-dimensional electrophoresis in polyacrylamide gel. The proteic maps were analyzed using the PDQuest application, version 8.0; Bio Rad, USA. There were significant differences over body weight and over the expression of the proteic spots of the muscle (P <0.05), but there was no significant difference for the seminal parameters, testicular biometry and the expression of seminal plasma proteins. The spots differentially expressed (P <0.05) were digested with trypsin and subjected to identification through mass spectrometry (ESI-Q-TOF). It is concluded, therefore, that the levels of concentrated provided to the animals change the body weight and influence the expression of the Longissimus dorsi muscle proteins, but do not modify the testicular biometry, the seminal parameters and the expression of seminal plasma proteins. / O estudo foi conduzido com o objetivo de avaliar os efeitos de diferentes níveis de suplementação concentrada sobre o peso corporal, parâmetros seminais, medidas de biometria testicular, perfil proteico do plasma seminal e perfil proteico do músculo Longissimus dorsi de carneiros da raça Morada Nova. Foram utilizados 22 carneiros com sete meses de idade. Os tratamentos consistiam em diferentes níveis de concentrado (0%, 0,6%, 1,2% e 1,8% do peso corporal do animal com base na matéria seca). Os animais foram mantidos em sistema de pastejo rotacionado em pasto de capim Aruana (Panicum maximum). As amostras de sêmen foram coletadas por eletroejaculação ao final do experimento, quando os animais obtiveram 10 meses de idade. Após o abate, os testículos e o músculo Longissimus dorsi foram coletados. Os testículos foram mensurados e as proteínas seminais e musculares foram analisadas por meio de eletroforese bidimensional em gel de poliacrilamida. Os mapas proteicos foram analisados por meio do aplicativo PDQuest, version 8.0; Bio Rad, USA. Houve diferença significativa no peso corporal e na expressão dos spots proteicos do músculo Longissimus dorsi (P < 0,05), porém não houve diferença significativa para os parâmetros seminais, biometria testicular e para a expressão de proteínas do plasma seminal. Os spots diferencialmente expressos (P < 0,05) foram digeridos com tripsina e submetidos à identificação por espectrometria de massa (ESI-Q-TOF). Conclui-se, portanto, que os níveis de concentrado fornecido aos animais alteram o peso corporal e a expressão de proteínas do músculo Longissimus dorsi, porém não influenciam as medidas de biometria testicular, os parâmetros seminais e a expressão de proteínas do plasma seminal.
22

Phase Retrieval and Hilbert Integral Equations – Beyond Minimum-Phase

Shenoy, Basty Ajay January 2018 (has links) (PDF)
The Fourier transform (spectrum) of a signal is a complex function and is characterized by the magnitude and phase spectra. Phase retrieval is the reconstruction of the phase spectrum from the measurements of the magnitude spectrum. Such problems are encountered in imaging modalities such as X-ray crystallography, frequency-domain optical coherence tomography (FDOCT), quantitative phase microscopy, digital holography, etc., where only the magnitudes of the wavefront are detected by the sensors. The phase retrieval problem is ill-posed in general, since an in nite number of signals can have the same magnitude spectrum. Typical phase retrieval techniques rely on certain prior knowledge about the signal, such as its support or sparsity, to reconstruct the signal. A classical result in phase retrieval is that minimum-phase signals have log-magnitude and phase spectra that satisfy the Hilbert integral equations, thus facilitating exact phase retrieval. In this thesis, we demonstrate that there exist larger classes of signals beyond minimum-phase signals, for which exact phase retrieval is possible. We generalize Hilbert integral equations to 2-D, and also introduce a variant that we call the composite Hilbert transform in the context of 2-D periodic signals. Our first extension pertains to a particular type of parametric modelling of 2-D signals. While 1-D minimum-phase signals have a parametric representation, in terms of poles and zeros, there exists no such 2-D counterpart. We introduce a new class of parametric 2-D signals that possess the exact phase retrieval property, that is, their magnitude spectrum completely characterizes the signal. Starting from the magnitude spectrum, a sequence of non-linear operations lead us to a sum-of-exponentials signal, from which the parameters are computed employing concepts from high-resolution spectral estimation such as the annihilating filter and algebraically coupled matrix-pencil methods. We demonstrate that, for this new class of signals, our method outperforms existing techniques even in the presence of noise. Our second extension is to continuous-domain signals that lie in a principal shift-invariant space spanned by a known basis. Such signals are characterized by the basis combining coefficients. These signals need not be minimum-phase, but certain conditions on the coefficients lead to exact phase retrieval of the continuous-domain signal. In particular, we introduce the concept of causal, delta dominant (CDD) sequences, and show that such signals are characterized by their magnitude spectra. This condition pertains to the time/spatial-domain description of the signal, in contrast to the minimum-phase condition, which is described in the spectral domain. We show that there exist CDD sequences that are not minimum-phase, and vice versa. However, finite-length CDD sequences are always minimum-phase. Our method reconstructs the signal from the magnitude spectrum up to ma-chine precision. We thus have a class of continuous-domain signals that are neither causal nor minimum phase, and yet allow for exact phase retrieval. The shift-invariant structure is applicable to modelling signals encountered in imaging modalities such as FDOCT. We next present an application of 2-D phase retrieval to continuous-domain CDD signals in the context of quantiative phase microscopy. We develop sufficient conditions on the interfering reference wave for exact phase retrieval from magnitude measurements. In particular, we show that when the reference wave is a plane wave with magnitude greater that the intensity of the object wave, and when the carrier frequency is larger than the band-width of the object wave, we can reconstruct the object wave exactly. We demonstrate high-resolution reconstruction of our method on USAF target images. Our final and perhaps the most unifying contribution is in developing Hilbert integral equations for 2-D first-quadrant signals and in introducing the notion of generalized minimum-phase signals for both 1-D and 2-D signals. For 2-D continuous-domain, first-quadrant signals, we establish partial Hilbert transform relations between the real and imaginary parts of the spectrum. In the context of 2-D discrete-domain signals, we show that the partial Hilbert transform does not suffice and introduce the notion of composite Hilbert transform and establish the integral equations. We then introduce four classes of signals (combinations of 1-D/2-D and continuous/discrete-domain) that we call generalized minimum-phase signals, which satisfy corresponding Hilbert integral equations between log-magnitude and phase spectra, hence facilitating exact phase retrieval. This class of generalized minimum-phase signals subsumes the well known class of minimum-phase signals. We further show that, akin to minimum-phase signals, these signals also have stable inverses, which are also generalized minimum-phase signals.
23

Understanding molecular aspects of catfish-pathogen interactions

Dumpala, Pradeepkumar Reddy 07 August 2010 (has links)
The catfish industry suffers losses primarily due to enteric septicemia of catfish and columnaris disease caused by Edwardsiella ictaluri and Flavobacterium columnare, respectively. Understanding the host-pathogen interactions is vital for prevention and eradication of these diseases. Hence, the overall objective of this study was to analyze whole cell proteomes of these two bacteria, and to determine the changes in E. ictaluri protein expression against in vitro iron-restriction and host serum treatment. High-throughput proteomic analysis of these bacteria was conducted using two-dimensional liquid chromatography followed by electrospray ionization tandem mass spectrometry (2-D LC ESI MS/MS) and two-dimentional gel electrophoresis coupled with matrix-assisted laser desorption/ionization time-oflight mass spectrometry (2-DE MALDI TOF/TOF). Identified proteins were clustered into functional groups using clusters of orthologous groups, and subcellular locations as well as possible functional relationships were determined. A total of 788 unique E. ictaluri and 621 unique F. columnare proteins were identified, which represented 12 and 28 pathways, respectively. Vertebrate hosts tend to chelate free iron of their body and make the environment hostile for bacteria. Hence, reduced availability of iron may cause significant stress for pathogens and is considered a signal that leads to alteration in virulent gene expression. Similarly, E. ictaluri might use the catfish blood stream effectively for quick systemic invasion. Hence, exposure to catfish serum components might reveal the ability of E. ictaluri to protect against host defense mechanisms. Using two-dimensional difference gel electrophoresis, responses of E. ictaluri due to in vitro iron-restriction and host serum treatment were determined. A total of 50 and 19 proteins were identified to be differentially expressed due to in vitro iron-restriction and catfish serum treatment, respectively. Among the differentially expressed proteins, several putative virulent determinants, immunogenic proteins, chaperones, and housekeeping genes were noted. To initiate functional studies, four differentially expressed E. ictaluri genes (lamB, glyS, malE, and sdhA) were mutated by inrame deletion. Results from this study provided experimental evidence for many predicted proteins. In addition, identification of differentially expressed proteins provided targets for further functional analysis, which could help elucidate pathogenic mechanisms of E. ictaluri.
24

Equalisation for carrierless amplitude and phase modulation

Gao, Jason January 2002 (has links)
Carrierless amplitude and phase (CAP) modulation is generally regarded as a bandwidth efficient two-dimensional (2-D) passband line code. It is closely related to the pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM) schemes. CAP has been proposed for various digital subscriber loop (DSL) systems over unshielded twisted pairs of copper wires. In this thesis, our main focus is on the minimum mean-square error (MMSE) performance of the ideal (i.e., infinite length) linear and non-linear (decision feedback) CAP receivers/equalisers in the presence of additive, coloured Gaussian noise, and/or data-like cross-talks. An in-depth analysis is given on the performance of both receiver structures. In the case of the linear receiver, one possible view of the overall CAP transceiver system which includes both data and cross-talk transmission paths is that it is a linear multiple-input multiple-output (MIMO) system. Accordingly, the existing MMSE results for a general MIMO system are applicable also to CAP systems. However, up to date, this approach was shown to be unsuccessful in the sense that the derived MMSE expressions are too complex and offer little insights. In our analysis, in order to find a more incisive MMSE expression, we reconsider the problem of minimisation of the MSEs at slicers. By exploiting the Hilbert transform pair relationship between the impulse responses of the inphase and quadrature transmit shaping filters, we are able to obtain an elegant and more meaningful MMSE expression, as well as the corresponding transfer functions of the optimum linear receive filters. In the case of the nonlinear, or decision feedback equaliser (DFE), receiver, we start our analysis with the receiver structure of a generic multidimensional (>/= 3) CAP-type system. / This receiver consists of a bank of analog receive filters, the number of which equals the dimension of the CAP line code, and a matrix of cross-connected, infinite-length, baud-spaced feedback filters. It is shown that the optimum filters and the corresponding MMSE of the DFE receiver require the factorisation of a discrete-time channel spectral matrix. This mathematically intractable step can be avoided, however, when the DFE results are specialised to a standard 2-D CAP system where we are able to again exploit the Hilbert transform pair relationship to derive a further and more useful MMSE expression. Three sets of numerical studies are given on the MMSE performance of the CAP receivers. In the first set of studies. we model the sum of all crosstalks as an additive, Gaussian noise source and select three test transmission channels over which we compare the MMSE performance of the linear and DFE receiver structures. In the second set of studies, we compare the performance of the two receiver structures, but in a data-like cross-talk environment. The results demonstrate the importance of NEXT equalisation in the design of CAP receivers operating in a NEXT dominant environment. In the final set of studies which follows from the second set of studies, we investigate the relationship between the MMSE performance of the DFE receiver and system parameters which include excess bandwidth, data rate, CAP scheme. and relative phase between the received signal and the NEXT signal. The results show that data-like cross-talks can be effectively suppressed by using a large excess bandwidth (alpha > 1 in the case of a RC transmit shaping filter) alone. / The relative phase also affect; the receiver performance. but to a lesser degree. In addition to the MMSE performance analysis. implementation issues of an adaptive linear CAP receiver are also considered. We propose a novel linear receiver by appending two fixed analog filters to the front-end of the existing adaptive linear receiver using fractionally-spaced equalisers (FSE). We show that if the analog filters are matched to the transmit shaping filters, then inphase and quadrature finite-length FSEs in the proposed receiver have the same NINISE solution. We further propose a modified least-mean-square (LMS) algorithm which takes advantage of this feature. The convergence analysis of the proposed LMS algorithm is also given. We show that the modified LMS algorithm converges approximately twice as fast as the standard LMS algorithm, given the same misadjustment, or alternatively, it halves the misadjustment, given the same initial convergence rate.
25

Design of an Analog VLSI Cochlea

Shiraishi, Hisako January 2003 (has links)
The cochlea is an organ which extracts frequency information from the input sound wave. It also produces nerve signals, which are further analysed by the brain and ultimately lead to perception of the sound. An existing model of the cochlea by Fragni`ere is first analysed by simulation. This passive model is found to have the properties that the living cochlea does in terms of the frequency response. An analog VLSI circuit implementation of this cochlear model in CMOS weak inversion is proposed, using log-domain filters in current domain. It is fabricated on a chip and a measurement of a basilar membrane section is performed. The measurement shows a reasonable agreement to the model. However, the circuit is found to have a problem related to transistor mismatch, causing different behaviour in identical circuit blocks. An active cochlear model is proposed to overcome this problem. The model incorporates the effect of the outer hair cells in the living cochlea, which controls the quality factor of the basilar membrane filters. The outer hair cells are incorporated as an extra voltage source in series with the basilar membrane resonator. Its value saturates as the input signal becomes larger, making the behaviour rather closer to that of a passive model. The simulation results show this nonlinear phenomenon, which is also seen in the living cochlea. The contribution of this thesis is summarised as follows: a) the first CMOS weak inversion current domain basilar membrane resonator is designed and fabricated, and b) the first active two-dimensional cochlear model for analog VLSI implementation is developed.
26

Parallel JPEG Processing with a Hardware Accelerated DSP Processor / Parallell JPEG-behandling med en hårdvaruaccelerarad DSP processor

Andersson, Mikael, Karlström, Per January 2004 (has links)
<p>This thesis describes the design of fast JPEG processing accelerators for a DSP processor. </p><p>Certain computation tasks are moved from the DSP processor to hardware accelerators. The accelerators are slave co processing machines and are controlled via a new instruction set. The clock cycle and power consumption is reduced by utilizing the custom built hardware. The hardware can perform the tasks in fewer clock cycles and several tasks can run in parallel. This will reduce the total number of clock cycles needed. </p><p>First a decoder and an encoder were implemented in DSP assembler. The cycle consumption of the parts was measured and from this the hardware/software partitioning was done. Behavioral models of the accelerators were then written in C++ and the assembly code was modified to work with the new hardware. Finally, the accelerators were implemented using Verilog. </p><p>Extension of the accelerator instructions was given following a custom design flow.</p>
27

Two-dimensional Photonic Crystals Fabricated by Nanoimprint Lithography

Chen, A., Chua, Soo-Jin, Fonstad, Clifton G. Jr., Wang, B., Wilhelmi, O. 01 1900 (has links)
We report on the process parameters of nanoimprint lithography (NIL) for the fabrication of two-dimensional (2-D) photonic crystals. The nickel mould with 2-D photonic crystal patterns covering the area up to 20mm² is produced by electron-beam lithography (EBL) and electroplating. Periodic pillars as high as 200nm to 250nm are produced on the mould with the diameters ranging from 180nm to 400nm. The mould is employed for nanoimprinting on the poly-methyl-methacrylate (PMMA) layer spin-coated on the silicon substrate. Periodic air holes are formed in PMMA above its glass-transition temperature and the patterns on the mould are well transferred. This nanometer-size structure provided by NIL is subjective to further pattern transfer. / Singapore-MIT Alliance (SMA)
28

Assessment Of Rock Slope Stability For A Coastal Area Near Kusadasi, Aydin, Turkey

Kaya, Yavuz 01 February 2013 (has links) (PDF)
The study area, which will be open to tourism in Kusadasi (Aydin), has steep and high cliffs near the Aegean coast. In the area where some slidings and rockfall problems occurred in the past the geological hazards should be investigated and nature-friendly remedial measures should be taken. The aim of this study is to perform engineering geological studies to:(i) search geological hazards, (ii) reveal the slope stability problems, (iii) recommend nature-friendly solutions in order to prevent/minimize the hazards and (iv)compare the results obtained from 2-D and 3-D rockfall analyses. To accomplish these tasks, the geological survey was performed, the information about the discontinuities was collected by means of scanline surveys, the rock samples were collected, the in-situ and laboratory tests were carried out, the slope stability and rockfall analyses were performed for different slope conditions, remedial measures were offered for the problematical areas considering the data obtained and the results of 2-D and 3-D analysis were compared. Under the light of these studies, rock removal, drainage, greening (vegetation), filling the caverns, wall building and erosion prevention were offered as remedial measures. The comparison of the 2-D and 3-D rockfall analyses shows that the end points and bounce height values are different for each method. The differences between the 2-D and 3-D model originate from the slope geometry, the algorithm used in the software and the different input parameters. According to the field observations, the 2-D model is more realistic than 3-D model.
29

Characteristic Analysis of Grating Assisted SOI Racetrack Resonators

Chang, Wei-Lun 23 July 2012 (has links)
Silicon-on-Insulator (SOI) micro-ring resonators (MRRs) are versatile elements in high-density integrated optics telecommunication systems. However, small inaccuracies in the fabrication process intensely deteriorate the response of SOI MRRs. By utilizing the racetrack resonator structures with strong coupling abilities, one can improve the fabrication tolerance. For the SOI racetrack resonators, the FSR is usually large. By introducing gratings into SOI racetrack resonators, the mutual mode coupling between the clockwise and counterclockwise modes can be induced and result in the resonance splitting. The grating-assisted SOI racetrack resonators can increase the operation wavelength and open up the possibility to overcome this limitation. In this thesis, we first use the 2-D FDTD method with the effective index method (EIM) to obtain the transmission spectra of the SOI racetrack resonators. The transmission spectra are then fitted by using the time-domain coupled mode theory (CMT) to obtain the quality factor and optical parameters of the SOI racetrack resonators. Next, we demonstrate the characteristics of mode splitting resulted from the mutual mode coupling between the clockwise and counterclockwise modes in the grating-assisted racetrack resonators by utilizing both the CMT and the 2-D FDTD method with the EIM. By tuning the grating configurations, such as the length or the structure of sidewall gratings, one can obtain the desired transmission spectrum of the grating-assisted racetrack resonators. Finally, we numerically investigate the temperature-dependent spectral characterics of the grating-assisted SOI racetrack resonator by taking the thermal-optic responce of the SOI materials into account. The thermal sensitivity of this device is 95.38 pm/¢XC, and the calculted properties can help the further designs based on the grating-assisted SOI racetrack resonators.
30

On-wafer 2-D electric-field-vector measurement using single-beam electro-optic probing technique

Chen, Wei-Hsuan 30 June 2000 (has links)
Electro-Optic(EO) probing techniques are advancing rapidly in recent years due to their superior performance in characterization of semiconductor devices and circuits. Although the conventional systems can only monitor the amplitude distribution of electric field, some advanced EO probing techniques are able to measure not only the electric-field amplitude, but also direction of the electric field. Because valuable information can be released in such as chamfered bending transmission lines, patch antennas and wireless devices, etc., EO probing technique becomes an important tool to the characterization of radio frequency devices. These systems often require two beams or two different EO crystals to differentiate the directions of the electric field under test because only one type of EO modulation, compressed/stretched deformation modulation, is utilized in the measurement. Therefore, the measurements are inaccurate and complicated due to the fact that the path length and EO interaction strength of the two probing beams are different. In this research, we demonstrate the EO probing technique with one beam and one EO crystal to extract 2-D electric-field vector using an additional modulation effect, i.e. rotational deformation modulation. This electric field vector measurement technique is compact, accurate and low cost. We not only prove that on-wafer 2-D electric-field-vector measurement using single-beam electro-optic probing technique is feasible theoretically and experimentally, but also combine rotational deformation modulation and compressed/stretched deformation modulation to a practical circuit measurement. Commercial software, Ansoft Maxwell 3-D Field Simulator, is employed to verify our measurements. Good agreement is obtained between experiment and simulation results. In addition to 2-D electric-field-vector measurement, we made an attempt to high-frequency real-time measurement. With the trend of low voltage operation in wireless communication, the most serious issue of high-frequency real-time EO probing technique is the improvement of signal to noise ratio. We tried to improve the stability of laser source, control the polarization of incident beam, and utilize Fabry-Perot filter in order to implement high-frequency real-time measurement. A bandwidth of 900 MHz was achieved, which is record-high to our knowledge.

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