Browsing by Subject "Noise"
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Item The aesthetics and politics of rumor : the making of Egyptian public culture(2012-12) Koerber, Benjamin William; El-Ariss, Tarek; Brustad, Kristen; Ali, Samer; Al-Batal, Mahmoud; Al-Ghadeer, MoneeraWhether as a distinct cultural form, or as a problem exaggerated and imagined by a paranoid interpretive bent, “rumor” (al-ishāʿa) claims a place in the writings of many Egyptian intellectuals, littérateurs, journalists, and politicians in the twentieth century that has yet to be adequately addressed and theorized. At the intersection of cultural studies and Arabic literature, this dissertation investigates rumor as a fiercely contested mode of reading and writing public culture in Egypt since 1952. Eschewing the legislative trend in the modern social and clinical sciences that has positioned rumor as an object to be combatted, or reduced it to the mechanisms and motives of mass psychology, I examine some of the many ways in which it generates, animates, or interferes with scenes in the lives of social actors as they move between the centers and peripheries of power. Rumor possesses both affirmative and destructive powers, often inseparably, and in order to theorize its complex imbrications with character, community, and culture beyond the urge to evaluative critique, I develop a host of concepts – such as noise, play, paranoia, and parody – capable of bringing this oft-neglected ambivalence into view. Notoriously resistant to analysis, whether due to is conceptual vagueness or ephemeral phenomenological status, rumor and the scenes it makes require a rethinking of the modes of scholarly writing that dominate the humanities and social sciences. A degree of mobility and eclecticism, drawn from the object itself in its flight across history and culture, imbues the organization and style of this dissertation: rumor is the object, and inspires the mode, of my investigation. Each of the three Parts of the dissertation investigates a different field of public culture in post-1952 Egypt. Part 1 analyzes the rhetoric and interpretive practices deployed by state actors in their confrontation with what they call “rumors.” Three historical events are taken as significant: the rhetorical and dramatic performances of the Free Officers in the early revolutionary period (1952-1954), the social scientific celebration of “planning” (takhṭīṭ) in 1964, and the Mubarak death rumors of 2007. While here rumor comes into view as the object of state discipline and paranoid interpretation, the remaining two Parts investigate its role in the performances of artists, littérateurs, and bloggers. Part 2 analyzes the literary texts of Gamal al-Ghitani, which are unique in their simultaneous recording and performing of rumors in Egyptian cultural politics at the turn of the millennium. Finally, Part 3 examines intersections between play, parody, and the paranoid style of interpretation in cyberspace, including an investigation into the blogging campaign “Mubarak Mat” (“Mubarak has Died,” 2008) and Ashraf Hamdi’s response to rumors spun by the counterrevolution (2011-2012). While rumor, across these many contexts, is deplored as a destructive force, it also, I contend, salvages possibility from necessity, explores alternatives to the status quo, and serves as an unexpected catalyst for innovative cultural and political forms. As noise, it creates disorder and generates a new order. It is at once in public culture, and making public culture.Item Bispectral analysis of nonlinear acoustic propagation(2011-05) Gagnon, David Edward; Hamilton, Mark F.; Wochner, Mark S.Higher-order spectral analysis of acoustical waveforms can provide phase information that is not retained in calculations of power spectral density. In the propagation of high intensity sound, nonlinearity can cause substantial changes in the waveform as frequency components interact with one another. The bispectrum, which is one order higher than power spectral density, may provide a useful measure of nonlinearity in propagation by highlighting spectral regions of interaction. This thesis provides a review of the bispectrum, places it in the context of nonlinear acoustic propagation, and presents spectra calculated as a function of distance for numerically propagated acoustic waveforms. The calculated spectra include power spectral density, quad-spectral density, bispectrum, spatial derivative of the bispectrum, bicoherence, and skewness function.Item Complex-amplitude noise and accuracy analysis of quantized analog optical processors(Texas Tech University, 1995-05) Morelli, Michael V.Within this dissertation, we estabHsh the accuracy limitations of hybrid optoelectronic processing systems based upon an empirical understanding of elemental device noise characteristics. We approach this investigation in three phases. In the first phase we develop an analytical understanding of the information-bearing signal space for discrete numeric processors and establish how generalized spatiotemporal noise processes introduce uncertainty into this signal space, resulting in accuracy limitations. The second phase estabHshes an empirical understanding of the intensity-based noise processes for common sources, modulators, and detectors used to construct these processing systems. The third phase develops an understanding, both analytically and empirically, of the complex-amplimde signal and noise characteristics of a variety of Hquid crystal spatial tight modulators. The investigation concludes with an interpretation of the accuracy implications resulting from the observed electrical, intensity, and complex-amplitude noise processes, and proposes techniques which may achieve accuracy enhancements in such systems.Item Design methodologies for variation-aware integrated circuits(2009-05-15) Samanta, RupakThe scaling of VLSI technology has spurred a rapid growth in the semiconductor industry. With the CMOS device dimension scaling to and beyond 90nm technology, it is possible to achieve higher performance and to pack more complex functionalities on a single chip. However, the scaling trend has introduced drastic variation of process and design parameters, leading to severe variability of chip performance in nanometer regime. Also, the manufacturing community projects CMOS will scale for three to four more generations. Since the uncertainties due to variations are expected to increase in each generation, it will significantly impact the performance of design and consequently the yield. Another challenging issue in the nanometer IC design is the high power consumption due to the greater packing density, higher frequency of operation and excessive leakage power. Moreover, the circuits are usually over-designed to compensate for uncertainties due to variations. The over-designed circuits not only make timing closure difficult but also cause excessive power consumption. For portable electronics, excessive power consumption may reduce battery life; for non-portable systems it may impose great difficulties in cooling and packaging. The objective of my research has been to develop design methodologies to address variations and power dissipation for reliable circuit operation. The proposed work has been divided into three parts: the first part addresses the issues related with power/ground noise induced by clock distribution network and proposes techniques to reduce power/ground noise considering the effects of process variations. The second part proposes an elastic pipeline scheme for random circuits with feedback loops. The proposed scheme provides a low-power solution that has the same variation tolerance as the conventional approaches. The third section deals with discrete buffer and wire sizing for link-based non-tree clock network, which is an energy efficient structure for skew tolerance to variations. For the power/ground noise problem, our approach could reduce the peak current and the delay variations by 50% and 51% respectively. Compared to conventional approach, the elastic timing scheme reduces power dissipation by 20% ? 27%. The sizing method achieves clock skew reduction of 45% with a small increase in power dissipation.Item Determining how noise and task redundancy influence motor control of planar reaching(2013-12) Nguyen, Hung Phuc, active 2013; Dingwell, Jonathan B.; Seepersad, Carolyn C.Motor noise and redundancy are vexing issues in motor control; yet their understanding provides great insights on underlying control mechanisms that govern movement. They provide glimpses into how the nervous system organizes and regulates movement within the motor control system. Understand of motor control could spur new advances in motor control could lead to better development of rehabilitation process and technology to counteract debilitating affects of neuromuscular disorders and motor readjustment with prostheses. However, before such process and technology could be developed and adapted for clinical use, a deeper understanding of motor control is needed to unravel the neural roadmap that regulates and generates movement. New theory of motor control could precipitate the development of more robust control mechanisms for robotic-human interaction. This work aims at expanding a more rigorous analytical and mathematical framework to understand how these control mechanisms reconcile redundancy and stochastic noise in human motor control.Item The effect of noise on the dynamics of a 2-D walking model(2011-08) Campbell, Bradley Cortez; Dingwell, Jonathan B.Walking models have been used to explore concepts such as energy, step variability, control strategies and redundancy in walking. A 2-D dynamic walking model was used to determine the levels of variability in gait while being perturbed. The perturbations were added in the form of randomly added noise applied at different magnitudes. The model was comprised of two equal length legs and masses at the feet and hips. The model walked on a flat surface and each step was initialed by an impulse at the swing leg. The magnitude of the impulse determined the size of the model's steps. In this study, the walker took steps with lengths that were than were analogous to humans. An attempt to offset the effect of the noise was made by adding a proportional controller to correct the errors of the applied impulse. The control equation was comprised of gain, A, and noise, [xi], term. The step length, time and speed were calculated to analyze how the model walks. It was hypothesized that the model would use a strategy similar to humans on a treadmill and follow a goal equivalent manifold. The manifold was all possible solutions of step length and step time for maintaining constant speed. Any fluctuations in step length and time would still result in constant speed. The results showed that the model's gait became more variable as noise was added. When the control was added through the gain being increased, the model steps became more variable. The model did not follow the same control strategy as humans and coordinate steps along the GEM. As the model began taking longer step lengths the step time decreased.Item Evaluation and extension of threaded control for high-mix semiconductor manufacturing(2010-12) Patwardhan, Ninad Narendra; Flake, Robert H.; Edgar, Thomas F.In the recent years threaded run-to-run (RtR) control algorithms have experienced drawbacks under certain circumstances, one such trait is when applied to high-mix of products such as in Application Specific Integrated Circuits (ASIC) foundries. The variations in the process are a function of the product being manufactured as well as the tool being used. The presence of semiconductor layers increases the number of times the lithography process must be repeated. Successive layers having different patterns must be exposed using different reticles/masks in order to maximize tool utilizations. The objectives of this research are to develop a set of methodologies for evaluation and extension of threaded control applied to overlay. This project defines methods to quantify the efficacy of threaded controls, finds the drawbacks of threaded control under production of high mix of semiconductors and suggests extensions and alternatives to improve threaded control. To evaluate the performance of threaded control, extensive simulations were performed in MATLAB. The effects of noise, disturbances, sampling and delays on the control and estimation performance of threaded controller were studied through these simulations. Based on the results obtained, several ideas to extend threaded control by reducing overall number of threads, by improving thread definitions and combination have been introduced. A unique idea of sampling the measurements dynamically based on the estimation accuracy is also presented. Future work includes implementing the extensions to threaded control suggested in this work in real production data and comparing the results without the use of those methods. Future work also includes building new alternatives to threaded control.Item Image compression in signal-dependent noise(Texas Tech University, 1995-08) Shahnaz, RubeenaThe performance of an image compression scheme is affected by the presence of noise in an image. This work mainly investigates the effects of signal-dependent noise on image compression using the JPEG image compression algorithm. Simulation results show that the achievable compression is significantly reduced in the presence of noise. The types of noise considered are, signal-independent additive noise, signal-dependent film-grain noise and speckle noise. For improvement of compression ratios noisy images are pre-processed for noise suppression before applying compression. Two approaches are used for reduction of signal-dependent noise prior to compression. In one approach estimator designed specifically for a particular signal-dependent noise model is used on the noise degraded image for noise suppression. In the second approach the signal-dependent noise is transformed into signal-independent noise using a homomorphic transformation. An estimator designed for signal-independent noise is then used on the transformed image for noise suppression followed by an inverse homomorphic transformation. The performances of these two pre-compression noise suppression schemes are compared using different performance criteria. Simulation results show that pre-compression noise suppression significantly increases the amount of compression obtained subsequently. The compression results for the noiseless, noisy and restored images are compared.Item Investigation into the effect of intermittent noise of constant periodicity vs. random periodicity on the performance of an industrial task(Texas Tech University, 1965-05) Fornwalt, Nevin ENot availableItem Linearity and Noise Improvement Techniques Employing Low Power in Analog and RF Circuits and Systems(2012-12-07) Abdel Ghany, EhabThe implementation of highly integrated multi-bands and multi-standards reconfigurable radio transceivers is one of the great challenges in the area of integrated circuit technology today. In addition the rapid market growth and high quality demands that require cheaper and smaller solutions, the technical requirements for the transceiver function of a typical wireless device are considerably multi-dimensional. The major key performance metrics facing RFIC designers are power dissipation, speed, noise, linearity, gain, and efficiency. Beside the difficulty of the circuit design due to the trade-offs and correlations that exist between these parameters, the situation becomes more and more challenging when dealing with multi-standard radio systems on a single chip and applications with different requirements on the radio software and hardware aiming at highly flexible dynamic spectrum access. In this dissertation, different solutions are proposed to improve the linearity, reduce the noise and power consumption in analog and RF circuits and systems. A system level design digital approach is proposed to compensate the harmonic distortion components produced by transmitter circuits? nonlinearities. The approach relies on polyphase multipath scheme uses digital baseband phase rotation pre-distortion aiming at increasing harmonic cancellation and power consumption reduction over other reported techniques. New low power design techniques to enhance the noise and linearity of the receiver front-end LNA are also presented. The two proposed LNAs are fully differential and have a common-gate capacitive cross-coupled topology. The proposed LNAs avoids the use of bulky inductors that leads to area and cost saving. Prototypes are implemented in IBM 90 nm CMOS technology for the two LNAs. The first LNA covers the frequency range of 100 MHz to 1.77 GHz consuming 2.8 mW from a 2 V supply. Measurements show a gain of 23 dB with a 3-dB bandwidth of 1.76 GHz. The minimum NF is 1.85 dB while the input return loss is greater than 10 dB across the entire band. The second LNA covers the frequency range of 100 MHz to 1.6 GHz. A 6 dBm third-order input intercept point, IIP3, is measured at the maximum gain frequency. The core consumes low power of 1.55 mW using a 1.8 V supply. The measured voltage gain is 15.5 dB with a 3-dB bandwidth of 1.6 GHz. The LNA has a minimum NF of 3 dB across the whole band while achieving an input return loss greater than 12 dB. Finally, A CMOS single supply operational transconductance amplifier (OTA) is reported. It has high power supply rejection capabilities over the entire gain bandwidth (GBW). The OTA is fabricated on the AMI 0.5 um CMOS process. Measurements show power supply rejection ratio (PSRR) of 120 dB till 10 KHz. At 10 MHz, PSRR is 40 dB. The high performance PSRR is achieved using a high impedance current source and two noise reduction techniques. The OTA offers a very low current consumption of 25 uA from a 3.3 V supply.Item Noise figure measurements in the communications receiver: and noise figure improvement by use of the cascode amplifier(Texas Tech University, 1950-08) Masterson, James E.NOT AVAILABLEItem Nonlinearity and noise modeling of operational transconductance amplifiers for continuous time analog filters(Texas A&M University, 2006-08-16) Ramachandran, ArunA general framework for performance optimization of continuous-time OTA-C (Operational Transconductance Amplifier-Capacitor) filters is proposed. Efficient procedures for evaluating nonlinear distortion and noise valid for any filter of arbitrary order are developed based on the matrix description of a general OTA-C filter model . Since these procedures use OTA macromodels, they can be used to obtain the results significantly faster than transistor-level simulation. In the case of transient analysis, the speed-up may be as much as three orders of magnitude without almost no loss of accuracy. This makes it possible to carry out direct numerical optimization of OTA-C filters with respect to important characteristics such as noise performance, THD, IM3, DR or SNR. On the other hand, the general OTA-C filter model allows us to apply matrix transforms that manipulate (rescale) filter element values and/or change topology without changing its transfer function. The above features are a basis to build automated optimization procedures for OTA-C filters. In particular, a systematic optimization procedure using equivalence transformations is proposed. The research also proposes suitable software implementations of the optimization process. The first part of the research proposes a general performance optimization procedure and to verify the process two application type examples are mentioned. An application example of the proposed approach to optimal block sequencing and gain distribution of 8th order cascade Butterworth filter (for two variants of OTA topologies) is given. Secondly the modeling tool is used to select the best suitable topology for a 5th order Bessel Low Pass Filter. Theoretical results are verified by comparing to transistor-level simulation withCADENCE. For the purpose of verification, the filters have also been fabricated in standard 0.5mm CMOS process. The second part of the research proposes a new linearization technique to improve the linearity of an OTA using an Active Error Feedforward technique. Most present day applications require very high linear circuits combined with low noise and low power consumption. An OTA based biquad filter has also been fabricated in 0.35mm CMOS process. The measurement results for the filter and the stand alone OTA have been discussed. The research focuses on these issues.Item Sound-politics in São Paulo, Brazil(2013-12) Cardoso, Leonardo de; Erlmann, VeitThe way a city sounds has something to do with how its residents move around and interact. It also has to do with the decisions made by the local government, as it tries to eliminate “harmful” and “unnecessary” sounds. This dissertation discusses how residents of São Paulo deal with noise conflicts and the sound-politics these mediations entail. The concept of sound-politics, which I develop throughout the dissertation, intersects with other concepts such as body politics and space politics and as such it denotes controversial sounds as instantiations of individual or collective differences. Here I focus on how state agents mediate controversial sounds. The narrative draws heavily on actor-network theory, which investigates social interaction as an open-ended and localized network made of humans and non-humans. The first part of the narrative discusses São Paulo’s spatial organization, noise legislation, and the enforcement of this legislation. Drawing from ethnography at meetings designed to review noise measurement standards, and at São Paulo’s anti-noise agency, I show the series of negotiations that accompany the identification and prosecution of noisemakers in the city. The second part of the dissertation looks closely at street parties that take place in the suburbs of São Paulo. Known as pancadões (“big thumps,” in reference to the loudness), these parties feature funk carioca and funk ostentação, two styles of popular music, among lower class teenagers in São Paulo’s suburbs. Based on fieldwork among youth, community meetings, and on interviews with police officers, I show how these parties have gone through noisification processes since they first emerged around 2008.