• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 9
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 39
  • 14
  • 13
  • 9
  • 9
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 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.
11

Evaluation Of Biodeterioration In Nemrut Mount Monument And Temple Of Augustus By Using Various Techniques

Sirt, Elif 01 September 2011 (has links) (PDF)
Different techniques were studied to evaluate the presence of different microorganisms that played important roles in decay processes of historic stones. In that scope, limestones and sandstones from Nemrut Mount Monument, and marbles and andesites from Temple of Augustus were studied. For measurement of enzymatic activity, fluorescein diacetate (FDA) hydrolysis method previously applied to assess soil microbial activity was carried out. Total microflora method based on countings of colony number was conducted for determination of the level of bacterial and fungal activity of stones. ATP bioluminescence method, developed for the field of hygiene monitoring, was carried out in order to detect global metabolic activity degree in historic stones. Most probable number (MPN) method was carried out to detect the number of microbial cells, namely nitrifying and sulphur oxidising bacteria which could take part in the decay processes. Moreover, fungi identification was done for determining occurance of detrimental species. Presence of lichenic and algal zones existed on stones of Nemrut Mount Monument and the presence of black discolorations on stones of Temple of Augustus was common. Results have shown that the bacterial and fungal activity was low, however considerable quantity of FDA hydrolyses has shown the importance of algal population in the stones of two studied historical sites. This study has proved that FDA hydrolyses, total microflora and MPN method were efficient for the evaluation of biodeterioration in historic stones.
12

Report of an internship with the Ohio River Valley Water Sanitation Sommission (ORSANCO) in Cincinnati, Ohio

Sundar, Naveen. January 2004 (has links)
Thesis (M. En.)--Miami University, Institute of Environmental Sciences, 2004. / Title from first page of PDF document. Includes bibliographical references (p. 33).
13

A qualitative model of evolutionary algorithms

Fagan, Francois 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Evolutionary Algorithms (EAs) are stochastic techniques, based on the idea of biological evolution, for finding near-optimal solutions to optimisation problems. Due to their generality and computational speed, they have been applied very successfully in a wide range of disciplines. However, as a consequence of their stochasticity and generality, very little has been rigorously established about their performance. Developing models for explaining and predicting algorithmic performance is, in fact, one of the most important challenges facing the field of optimisation. A qualitative version of such a model of EAs is developed in this thesis. There are two paradigms for explaining why EAs are expected to converge toward an optimum. The traditional explanation is that of Universal Darwinism, but an alternative explanation is that they are hill climbing algorithms which utilise all possible escape strategies — restarting local search, stochastic search and acceptance of non-improving solutions. The combination of the hill climbing property and the above escape strategies leads to a fast algorithm that is able to avoid premature convergence. Due to the difficulty in mathematically or empirically explaining the performance of EAs, terms such as exploitation, exploration, intensity and diversity are routinely employed for this purpose. Six prevalent views on exploitation and exploration are identified in the literature, each expressing a different facet of these notions. The coherence of these views is substantiated by their deducibility from the proposed novel definitions of exploitation and exploration. This substantiation is based on a novel hypothetical construct, namely that of a Probable Fitness Landscape (PFL), which both unifies and clarifies the surrounding terminology and our understanding of the performance of EAs. The PFL is developed into a qualitative model of EAs by extending it to the notion of an Ideal Probability Distribution (IPD). This notion, along with the criteria of diversity and computational speed, forms a method for judging the performance of EA operators. It is used to explain why the principal operators of EAs, namely mutation and selection, are effective. There are three main types of EAs, namely Genetic Algorithms (GAs), Evolution Strategies and Evolutionary Programming, each of which employ their own unique operators. Important facets of the crossover operator (which is particular to GAs) are identified, such as: opposite step vectors, genetic drift and ellipsoidal parent-centred probability distributions with variance proportional to the distance between parents. The shape of the crossover probability distribution motivates a comparison with a novel continuous approximation of mutation, which reveals very similar underlying distributions, although for crossover the distribution is adaptive whereas for mutation it is fixed. The PFL and IPD are used to analyse the crossover operator, the results of which are contrasted with the traditional explanations of the Schema Theorem and Building Block Hypothesis as well as the Evolutionary Progress Principle and Genetic Repair Hypothesis. It emerges that the facetwise nature of the PFL extracts more sound conclusions than the other explanations which, falsely, attempt to prove GAs to be superior. / AFRIKAANSE OPSOMMING: Evolusionere Algoritmes (EAs) is stogastiese tegnieke vir die bepaling van naby-optimale oplossings vir optimeringsprobleme wat gebaseer is op die beginsel van biologiese evolusie. As gevolg van hul algemene toepasbaarheid en hoe berekeningspoed, is hierdie algoritmes al met groot sukses in ’n wye verskeidenheid dissiplines toegepas. Die stogastiese aard en algemene toepasbaarheid van hierdie klas van algoritmes het egter tot gevolg dat baie min al oor hul werkverrigting formeel bewys is. Die ontwikkeling van modelle waarmee die doeltreffendheid van algoritmes verklaar en voorspel kan word, is trouens een van die grootste uitdagings in die studieveld van optimering. ’n Kwalitatiewe weergawe van so ’n model word in hierdie verhandeling vir EAs daargestel. Daar bestaan twee paradigmas vir die verklaring van waarom daar van EAs verwag word om na ’n optimum te konvergeer. Die tradisionele verklaring geskied aan die hand van Universele Darwinisme, maar ’n alternatiewe verklaring is dat hierdie algoritmes bergtop-soekend is en van alle moontlike ontsnapstrategiee gebruik maak — lokale soekstrategiee, stogastiese soekstrategiee en die aanvaarding van minderwaardige oplossings. Die kombinasie van die bergtop-soekende eienskap en die insluiting van die bogenoemde ontsnapstrategiee gee aanleiding tot vinnige algoritmes wat daartoe in staat is om voortydige konvergensie te vermy. Omdat dit moeilik is om die werkverrigting van EAs wiskundig of empiries te verklaar, word terminologie soos uitbuiting, verkenning, intensiteit en diversiteit roetinegewys vir hierdie doel ingespan. Ses heersende menings in die literatuur oor uitbuiting en verkenning word ge¨ıdentifiseer wat elkeen ’n ander faset van hierdie begrippe uitlig. Die samehang van hierdie menings word deur hul afleibaarheid uit nuwe definisies van uitbuiting en verkenning gedemonstreer. Hierdie demonstrasie is gebaseer op ’n nuwe hipotetiese konstruk, naamlik die van ’n Waarskynlike Fiksheidslandskap (WFL), wat beide die omliggende terminologie¨e en ons begrip van die werking van EAs enersyds verenig en andersyds verduidelik. Die begrip van ’n WFL word tot ’n kwantitatiewe model vir EAs ontwikkel deur dit tot die konstruk van ’n Ideale Waarskynlikheidsverdeling (IWV) uit te brei. Hierdie konsep word saam met die kriteria van diversiteit en berekeningspoed gebruik om ’n metode te ontwikkel waarmee die werkverrigting van EAs beoordeel kan word. Die IWV word gebruik om te verklaar waarom die hoofoperatore van EAs, naamlik mutasie en seleksie, doeltreffend is. Daar is drie tipes van EAs, naamlik Genetiese Algoritmes (GAs), Evolusionere Strategiee en Evolusionere Programmering, wat elk hul eie, unieke operatore bevat. Belangrike fasette van die oorgangsoperator (wat eie is aan GAs) word uitgelig, soos regoorstaande trapvektore, genetiese neiging en ellipsoıdale ouer-gesentreerde waarskynlikheidsverdelings met variansies wat eweredig is aan die afstand tussen ouers. Die vorm van die oorgangs-waarskynlikheidsverdeling gee aanleiding tot ’n vergelyking tussen die begrip van oorgang en ’n nuwe, kontinue benadering van mutasie. Daar word gevind dat die onderliggende verdelings baie soortgelyk is, alhoewel die oorgangsverdeling aanpasbaar is, terwyl die verdeling vir mutasie vas is. Die WFL en IWV word gebruik om die oorgangsoperator te analiseer en die resultate van hierdie analise word teenoor die tradisionele verklarings van die Skemastelling en Boublok-hipotese sowel as die Evolusionere Vooruitgangsbeginsel en die Genetiese Herstel-hipotese gekontrasteer. Dit blyk dat meer grondige gevolgtrekkings gemaak kan word uit die fasetgewyse aard van die WFL as uit ander verklarings wat valslik poog om die meer doeltreffende werkverrigting van GAs te demonstreer. Die gebruik van faset-gewyse en kwalitatiewe modelle word geregverdig deur hul sukses in terme van die verklaring van EA werkverrigting. Die argument word gemaak dat die beste rigting vir voortgesette navorsing oor EAs is om weg te bly van vergelykende studies en die afleiding van sogenaamde vergelykings van beweging, maar om eerder die ontwikkeling van wetenskaplikgefundeerde, faset-gewyse modelle vir algoritmiese werkverrigting na te streef.
14

Impacto del cambio climático en eventos extremos y análisis de la vulnerabilidad de algunas obras hidráulicas en Chile

Lagos Zúñiga, Miguel Ángel January 2012 (has links)
Magíster en Ciencias de la Ingeniería, Mención Recursos y Medio Ambiente Hídrico / Ingeniero Civil / En las últimas décadas se ha observado a nivel mundial un calentamiento global que en Chile Central tiende a +2.8°C/siglo. Las implicancias de este incremento de temperatura, se traducen en una disminución de los cuerpos glaciares y nieves, lo que por un lado afecta la disponibilidad del recurso hídrico para las actividades humanas y por otro lado genera que un aumento de las áreas sobre las que cae precipitación líquida. Estudios mundiales de cambio climático han pronosticado potenciales aumentos en intensidades de precipitación, aún en zonas donde la lluvia anual disminuya en el tiempo. Teniendo entonces lluvias más intensas y temperaturas más elevadas, las grandes obras hidráulicas serían vulnerables ante posibles proyecciones de cambio climático. En la determinación de los caudales de diseño realizados en la actualidad, para cuencas de régimen hidrológico mixto, se suelen construir hidrogramas unitarios, con los que se generan crecidas más severas a las históricas al aplicarle los efectos de tormentas de periodos de retorno mayores, sin embargo, el supuesto de un hidrograma unitario único en estos sistemas, deja de lado el hecho que la severidad de una crecida no solo depende de la intensidad de la lluvia de diseño, sino que además de la temperatura a la que esta ocurre. Debido a que la mayoría de las grandes obras hidráulicas en Chile se diseñan para eventos de periodo de retorno (T) de 1000 a 10 000 años, verificando en algunos casos para la Crecida Máxima Probable (CMP), se analizan en este estudio los efectos de los escenarios climáticos A2 y B1 (2045-2065) en la Precipitación Máxima Probable (PMP) determinada estadísticamente en las regiones de Coquimbo y Maule, e hidrometeorológicamente en la Cuenca Puclaro. Se estudian además las tendencias de las estaciones pluviométricas de mayor registro cercanas a los embalses Puclaro y Colbún con 10 modelos de circulación general de la atmósfera para los eventos de 24 hrs de 1000 y 10 000 años de periodo de retorno. En el caso de las crecidas, se estudia como evolucionarían los eventos de origen pluvial de T= 1000 y 10 000 años y la CMP. Los resultados muestran que para las cuencas Puclaro y Colbún se proyectan los incrementos más severos de precipitación de 20% y 30% respectivamente, siendo estos aumentos mayores al nivel regional en las zonas de mayor elevación. En el caso del embalse Puclaro se proyectan los incrementos más severos de 85% y 81% en las crecidas de 1000 y 10000 años, mientras que la CMP proyecta incrementos de hasta 175.5% para el escenario A2 en el mismo embalse. Todos estos resultados, que además incluyen un análisis de incertidumbre estadística, proyectan que existe una vulnerabilidad en los embalses Puclaro y Colbún frente a escenarios de cambio climático, siendo estos resultados generalizables a regiones de similares proyecciones climáticas y régimen hidrológico mixto.
15

IMPROVING EXTREME PRECIPITATION ESTIMATES CONSIDERING REGIONAL FREQUENCY ANALYSIS / 地域頻度解析を考慮した極端降水推定値の精度向上に関する研究

Nor Eliza Binti Alias 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18562号 / 工博第3923号 / 新制||工||1603(附属図書館) / 31462 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 寶 馨, 教授 中北 英一, 教授 田中 茂信 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
16

Improvement of the quantitation method for the tdh+ Vibrio parahaemolyticus in molluscan shellfish based on most-probable- number, immunomagnetic separation, and loop-mediated isothermal amplification / 最確数法、免役磁気分離法、およびloop-mediated isothermal amplification 法に基づく軟体動物貝類中のtdh+ 腸炎ビブリオの定量検査法の改良

Escalante, Maldonado Oscar Roberto 23 March 2016 (has links)
Final publication is available at: http://journal.frontiersin.org/article/10.3389/fmicb.2015.00270/full / 付記する学位プログラム名:グローバル生存学大学院連携プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19619号 / 医博第4126号 / 新制||医||1015(附属図書館) / 32655 / 京都大学大学院医学研究科医学専攻 / (主査)教授 中川 一路, 教授 木原 正博, 教授 松林 公蔵 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
17

Analysis of Risks to the Hydropower Sector under Climate Change

Wasti, Asphota 06 June 2023 (has links)
No description available.
18

REPORT OF AN INTERNSHIP WITH THE OHIO RIVER VALLEY WATER SANITATION COMMISSION IN CINCINNATI, OHIO

Sundar, Naveen 10 August 2004 (has links)
No description available.
19

In Their Own Words: Faculty/Staff and Student Accounts of Stress at Virginia Tech on April 16, 2007

McLeese, Michelle Frances 05 September 2017 (has links)
This study examines the stressful responses of faculty/staff and students after experiencing the April 16, 2007 school shootings at Virginia Tech. Understanding people's responses to trauma not only assists in more knowledge about what is stressful after a traumatic event but also may facilitate the finessing of tools and strategies for resilience and recovery in the aftermath of trauma. After investigating stressful responses to the April 16, 2007 shootings at Virginia Tech, and in particular those with probable PTSD (posttraumatic stress disorder), I found it was not always necessary to meet the "stressor" A criterion of PTSD. This is crucial because the "stressor" criterion A of PTSD is required to receive the diagnosis of PTSD. Although I found subtle stress differences for women compared to men, and faculty/staff compared to students, none of the differences were statistically significant. This research additionally contributes to the literature by detailing a profile of stressors for both faculty/staff and students in the aftermath of the worst college campus shooting in U.S. history to date. Findings suggest future research should examine the "stressor" criterion A of PTSD as well as the full spectrum of stressful responses both in the "immediate" and "delayed" aftermath of trauma(s). / Ph. D.
20

Comparing the mannitol-egg yolk-polymyxin agar plating method to the three tube most probable number method for enumeration of bacillus cereus spores in raw and high-temperature-short-time pasteurized milk

Harper, Nigel Murray January 1900 (has links)
Master of Science / Food Science Institute- Animal Sciences and Industry / Kelly J. K. Getty / The Food and Drug Administration’s Bacteriological Analytical Manual recommends two enumeration methods for Bacillus spp.: 1) standard plating method using mannitol-egg yolk-polymyxin (MYP) agar and 2) most probable number (MPN) method with tryptic soy broth supplemented with 0.1% polymyxin sulfate. Preliminary research evaluated three inoculum preparation methods using EZ-Spore™ B. cereus pellets. Two methods involved EZ-Spore™ B. cereus pellets that were dissolved in deionized (DI) water, grown in brain heart infusion broth with manganese sulfate, and then heated to produce spores. The third inoculum preparation method of dissolving EZ-Spore™ pellets only in DI water was the most efficient due to 100% spores being present in the inoculum. Preliminary research also determined that MPN method recovered greater (p<0.05) B. cereus populations than MYP method in inoculated ultra-high temperature pasteurized skim and 2% milk. The objective of the main study was to compare the MYP and MPN method for detection and enumeration of B. cereus in raw and high-temperature-short-time pasteurized skim, 2%, and whole milk at 4 °C for 96 h. Milk samples were inoculated with B. cereus EZ-Spores™ dissolved in DI water and sampled at 0, 48, and 96 h after inoculation. No differences (p>0.05) were observed among sampling times so data was pooled for overall mean values for each treatment. The overall B. cereus population mean of pooled sampling times for MPN method (2.59 log CFU/mL) was greater (p<0.05) than MYP plating method (1.89 log CFU/mL). B. cereus populations ranged from 3.40 log CFU/mL to 2.40 log CFU/mL for inoculated milk treatments for MYP and MPN methods, which is well below the necessary level for toxin production. Even though MPN method enumerated more B. cereus, the MYP method should be used by industry for enumeration of B. cereus due to its ease of use and rapid turnover time (2 d compared to 5 d with MPN). However, MPN method should be used for validation research due to its greater populations recovered. EZ-Spore™ B. cereus pellets were found to be an acceptable spore inoculum for validation research because the inoculum consists of 100% spores and does not contain vegetative cells.

Page generated in 0.0498 seconds