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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.
61

Reliability Analysis and Cost Benefit Evaluation of Reliability Enhancement for an Industrial Power Systems

Wang, Neng-pin 26 November 2005 (has links)
To evaluate the strategy of reliability enhancement for an existing industrial power system , the Benefit-Cost ratio of all possible improvement scenarios have to be investigated . This thesis presents a quantitative and systematic method to solve the Benefit-Cost ratio of network restructure for reliability enhancement . This method can provide a simple and effective tool for planning reliability improvement in the industry power systems. Up to now , many methodologies have been developed to solve the service reliability for distribution power systems . In this thesis , the reliability indices of industrial power systems are calculated to evaluate the service quality . According to the result of reliability analysis and the corresponding cost of loss of load for each load bus , the annual power outage cost is derived for each scenario of system restructure. By integrating the power outage cost and the corresponding investment cost , the optimal reliability enhancement is determined by the best strategy with the Benefit-Cost ratio.
62

Image enhancement for improving visibility and feature recognition

Zubair, Juwairia 10 October 2008 (has links)
Researchers analyze images in areas such as geology, bat cardiovascular systems and art studies to verify their observations. Some images are hard to study as their details are not vivid; hence there is a need to enhance these images to facilitate their study while preserving their contents. This study is aimed at assisting the researchers in the Cardiovascular Systems Dynamic Laboratory at Texas A&M University by evaluating the importance of Image Enhancement (IE) for improving visibility of features. For this study the images were collected and manipulated using various IE techniques and were shown to the novice researchers who were asked to perform three different tasks. These tasks were representative of the research work conducted in the lab. The techniques that were selected aimed at reducing the problems that are usually associated with data obtained from microscopic feeds. A customized application was developed to expedite and automate the study. The results indicated that the researchers did not immmensely benefit from the improved visualization for easy tasks. However, their performance improved for tasks that required more practice and skill. Our approach contributes towards designing an effective training program for novice researchers in the lab. Moreover, it is promising for similar research in different fields of study.
63

A Capabilities Solution to Enhancement Inequality

Swindells, Fox January 2014 (has links)
Human enhancements will dramatically alter individuals' capabilities and lead to serious harm if unregulated. However, it is unclear how states should act to mitigate this harm. I argue that the capabilities approach provides a useful metric to determine what action states should take regarding each enhancement technology. According to the capabilities approach, states are responsible for ensuring their citizens are able to function in certain ways that are essential to human life. I consider the impact of a range of enhancements on individuals' capabilities in order to determine what actions states should take regarding each technology. I find that in order to be just and prevent harmful inequality, states will need to ensure many enhancements are available to their citizens. I also explore a range of other regulations aimed at harm prevention. Considering the impact of enhancement technologies on human capabilities, and the appropriate regulatory options for states, under the guide of the capabilities approach allows me to demonstrate that the capabilities approach can provide valuable, realistic, advice to guide public policy in response to enhancement technologies.
64

Βελτίωση ψηφιακής φωτογραφίας

Μαστραπάς, Αναστάσιος 19 October 2009 (has links)
- / -
65

An Argument in Favor of Human Genetic Enhancement

West-Oram, Peter 19 September 2008 (has links)
Human Genetic Enhancement (HGE) has the potential to provide great benefits to a large number of people in terms of alleviating inherited disease and disability and maximizing individual liberty. There are many arguments against research and application of this new technology based on a variety of grounds, including both deontological and consequentialist objections. In this thesis I examine arguments from both of these positions and argue that neither offers a satisfactory justification for prohibiting research into HGE nor do they demonstrate that the application of the knowledge gained from such research is necessarily wrong. I also suggest that there is a strong argument in favor of HGE in that it may offer a way to reduce the amount of disadvantage currently present in our society as a result of genetic disease and disability by addressing the genetic causes of these conditions. Further, I argue that the pursuit of HGE is necessary in order to promote individual liberty and promote equality of opportunity. Finally, I argue that by examining principles that require us to promote individual liberty we can establish the categories of enhancements which we should publicly fund and those that should merely be permissible. / Thesis (Master, Philosophy) -- Queen's University, 2008-09-18 17:05:35.143
66

A Speech Enhancement System Based on Statistical and Acoustic-Phonetic Knowledge

Sudirga, RENITA 25 August 2009 (has links)
Noise reduction aims to improve the quality of noisy speech by suppressing the background noise in the signal. However, there is always a tradeoff between noise reduction and signal distortion--more noise reduction is always accompanied by more signal distortion. An evaluation of the intelligibility of speech processed by several noise reduction algorithms in [23] showed that most noise reduction algorithms were not successful in improving the intelligibility of noisy speech. In this thesis, we aim to utilize acoustic-phonetic knowledge to enhance the intelligibility of noise-reduced speech. Acoustic-phonetics studies the characteristics of speech and the acoustic cues that are important for speech intelligibility. We considered the following questions: what is the noise reduction algorithm that we should use, what are the acoustic cues that should be targeted, and how to incorporate this information into the design of the noise reduction system. A Bayesian noise reduction method similar to the one proposed by Ephraim and Malah in [16] is employed. We first evaluate the goodness-of-fit of several parametric PDF models to the empirical speech data. For classified speech, we find that the Rayleigh and Gamma. with a fixed shape parameter of 5, model the speech spectral amplitude equally well. The Gamma-MAP and Gamma-MMSE estimators are derived. The subjective and objective performances of these estimators are then compared. We also propose to apply a class-based cue-enhancement, similar to those performed in [21]. The processing directly manipulates the acoustic cues known to be important for speech intelligibility. We assume that the system has the sound class information of the input speech. The scheme aims to enhance the interclass and intraclass distinction of speech sounds. The intelligibility of speech processed by the proposed system is then compared to the intelligibility of speech processed by the Rayleigh-MMSE estimator [16] The intelligibility evaluation shows that the proposed scheme enhances the detection of plosive and fricative sounds. However, it does not help in the intraclass discrimination of plosive sounds, and more tests need to be done to evaluate whether intraclass discrimination of fricatives is improved. The proposed scheme deteriorates the detection of nasal and affricate sounds. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2009-08-24 21:32:48.966
67

Single-Microphone Speech Dereverberation: Modulation Domain Processing and Quality Assessment

ZHENG, CHENXI 25 July 2011 (has links)
In a reverberant enclosure, acoustic speech signals are degraded by reflections from walls, ceilings, and objects. Restoring speech quality and intelligibility from reverberated speech has received increasing interest over the past few years. Although multiple channel dereverberation methods provide some improvements in speech quality/ intelligibility, single-channel dereverberation remains an open challenge. Two types of advanced single-channel dereverberation methods, namely acoustic domain spectral subtraction and modulation domain filtering, provide small improvement in speech quality and intelligibility. In this thesis, we study single-channel dereverberation algorithms. Firstly, an upper bound of time-frequency masking (TFM) performance for dereverberation is obtained using ideal time-frequency masking (ITFM). ITFM has access to both the clean and reverberated speech signals in estimating the binary-mask matrix. ITFM implements binary masking in the short time Fourier transform (STFT) domain, preserving only those spectral components less corrupted by reverberation. The experiment results show that single-channel ITFM outperforms four existing multi-channel dereverberation methods and suggest that large potential improvements could be obtained using TFM for speech dereverberation. Secondly, a novel modulation domain spectral subtraction method is proposed for dereverberation. This method estimates modulation domain long reverberation spectral variance (LRSV) from time domain LRSV using a statistical room impulse response (RIR) model and implements spectral subtraction in the modulation domain. On one hand, different from acoustic domain spectral subtraction, our method implements spectral subtraction in the modulation domain, which has been shown to play an important role in speech perception. On the other hand, different from modulation domain filtering which uses a time-invariant filter, our method takes the changes of reverberated speech spectral variance along time into account and implements spectral subtraction adaptively. Objective and informal subjective tests show that our proposed method outperforms two existing state-of-the-art single-channel dereverberation algorithms. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2011-07-20 03:18:30.021
68

Attenuating desirable responding: a comparison of self-compassion and self-affirmation strategies

O'Brien, Karen Angela 10 September 2011 (has links)
Research has shown that desirable responding can be detrimental to social relationships, achievement and health. This study used an experimental design to (a) induce an increase in desirable responding through threat to self-image and then (b) compare the effectiveness of self-compassionate and self-affirming writing in attenuating that increase. Control groups included no threat exposure, threat exposure alone and threat exposure plus neutral writing. Desirable responding was measured along two dimensions: self-enhancement and exaggerated virtue. Results show the threat did not result in the predicted increase in desirable responding so the effectiveness of the two strategies with regards to attenuating increases in desirable responding could not be examined and compared. However, results do reveal a difference in the mechanism of these two strategies. Engaging in self-compassionate writing resulted in a significant decrease in exaggerated virtue whereas being self-affirmed resulted in a significant increase, suggesting a possible benefit of a self-compassion strategy.
69

Processing and characterisation of nano-enhanced composites

Frederick, Armstrong January 2009 (has links)
Since the discovery of nanomaterials in early ninety’s, a remarkable progress in the synthesis of nanocomposites has been reported looking for a new better material with improved physical and chemical properties for a variety of applications in almost all fields. The science and technology of nanocomposites has created great excitement and expectations in the last decade too. In addition to that, researches in this area have been focusing on the nanoscale second phase embedded in the polymeric matrix that gives physical and chemical properties that cannot be achieved by ordinary material synthesis methods. Researchers have also discovered that incorporating the right amount of nanoparticles into a polymer matrix pose a remarkable strength and flexibility and that industries should be able to integrate the outcome of their researches widely in high performance applications in the field of biomedical engineering, aerospace, marine, high speed parts in engines, packaging and sports gadgets. With the new methods of synthesis and tools for characterisation, nanocomposite science and technology is now experiencing explosive growth. Taking advantage of the need and the properties of the nanomaterials, through this research a new nano-enhanced composite is developed through addition of nanofiller into epoxy matrix to cater for varied applications. The physical and mechanical properties of the identified nanomaterial reinforced polymer composite were characterised by experimentation in order to ascertain the improvement in tensile, compressive and flexural properties as well as the adhesion of the matrix to the substrate. Also, while addressing potential enhancements like improved mechanical strength, better dimensional stability, higher thermal stability, better abrasion resistance, hard and wear resistance, better chemical properties like better flame retardance, anticorrosive and antioxidation, adequate importance was given to easy and bulk processability and most importantly the commercial viability as well. This nano-enhanced nanocomposite was then optimised. Based on these results, it has been established that epoxy reinforced with 1% percent of nanoclay can significantly improve the mechanical properties without compromising the weight or processability of the composite. Thus, a futuristic and much promising nano-enhanced epoxy composite has been successfully made ready for commercialisation.
70

Processing and characterisation of nano-enhanced composites

Frederick, Armstrong January 2009 (has links)
Since the discovery of nanomaterials in early ninety’s, a remarkable progress in the synthesis of nanocomposites has been reported looking for a new better material with improved physical and chemical properties for a variety of applications in almost all fields. The science and technology of nanocomposites has created great excitement and expectations in the last decade too. In addition to that, researches in this area have been focusing on the nanoscale second phase embedded in the polymeric matrix that gives physical and chemical properties that cannot be achieved by ordinary material synthesis methods. Researchers have also discovered that incorporating the right amount of nanoparticles into a polymer matrix pose a remarkable strength and flexibility and that industries should be able to integrate the outcome of their researches widely in high performance applications in the field of biomedical engineering, aerospace, marine, high speed parts in engines, packaging and sports gadgets. With the new methods of synthesis and tools for characterisation, nanocomposite science and technology is now experiencing explosive growth. Taking advantage of the need and the properties of the nanomaterials, through this research a new nano-enhanced composite is developed through addition of nanofiller into epoxy matrix to cater for varied applications. The physical and mechanical properties of the identified nanomaterial reinforced polymer composite were characterised by experimentation in order to ascertain the improvement in tensile, compressive and flexural properties as well as the adhesion of the matrix to the substrate. Also, while addressing potential enhancements like improved mechanical strength, better dimensional stability, higher thermal stability, better abrasion resistance, hard and wear resistance, better chemical properties like better flame retardance, anticorrosive and antioxidation, adequate importance was given to easy and bulk processability and most importantly the commercial viability as well. This nano-enhanced nanocomposite was then optimised. Based on these results, it has been established that epoxy reinforced with 1% percent of nanoclay can significantly improve the mechanical properties without compromising the weight or processability of the composite. Thus, a futuristic and much promising nano-enhanced epoxy composite has been successfully made ready for commercialisation.

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