Crop yields are coming under pressure to continue to grow in the face of climate change, competition, disease and pressure to reduce inputs. Photosynthetic efficiency is being targeted for improvement to increase yields. This study examined the variation in parameters of photosynthetic efficiency including canopy structure (leaf length, canopy angle, and chlorophyll content and growth rate) and gas exchange (photosynthetic rate, stomatal density and chlorophyll fluorescence) in Spring Barley (Hordeum vulgare ssp vulgare). These were first established for modern cultivars representing the most widely grown lines in the last 60 years. As cultivars are developed from a small pool of parents they may have limited genetic variation available for breeding. Landraces have been suggested as sources of variation. Using field and growth cabinet based studies the photosynthetic efficiencies of canopy structure and gas exchange were established for a range of European landraces under high and low nutrient inputs. This study demonstrated that in modern cultivars the leaf length increased with year of release from 23.2 to 29.6 cm and the chlorophyll content decreased from 46.9 to 34.8 SPAD units. Once the ear had emerged no difference was seen in canopy structure or photosynthetic rate. There was variation in landrace canopy establishment rate, leaf angle and number of leaves present within the canopy. The landraces from Northern European latitudes pushed though booting and reached full canopy establishment up to 8 days sooner than those from Southern Europe. This may be a response to a shorter growth season at Northern latitudes requiring the canopy to be established quickly. The landraces held the leaves within their canopy in a more horizontal position than the Southern European lines with leaf angle ranging from 18-45 degrees at GS39 and 31-84 degrees at GS59. This regressed negatively with temperature so it may be that a vertical canopy structure is beneficial in areas with higher temperatures. The photosynthetic rate of the landraces showed no variation but when chlorophyll fluorescence examined the efficiency of photosystem II (PSII) there was a positive regression of Fv/Fm ratio with latitude. This suggested that lines from Southern Europe were experiencing a greater stress with a ratio of up to 0.822 compared to those lines from the North with ratios from 0.767. The stomatal density of the landraces showed a large difference in ranges from 22-41 stomata between the lines. When high and low nutrient inputs were compared reductions from a ratio of 0.48 to 0.47 in Harvest Index and from 55g to 52g in 1000 grain weight were seen. The chlorophyll content of the lines was also reduced from 41.7 to 39.2 SPAD units at GS39 and from 44.9 to 39.8 SPAD units at GS59 by the reduction in nutrient inputs which may be a result of less N available for the production of chlorophyll. In conclusion there is variation present in canopy structure in European landraces that may be useful for future breeding or in identifying landrace collections which could be targeted for traits of interest in photosynthetic efficiency. These landraces may provide traits which could be used to develop cultivars which are locally adapted to climate and environmental conditions.

I takt med att ubåtarna blir allt tystare och svårare att detektera ställs allt högre krav på de sensorer som utvecklas för hålla jämna steg med denna utveckling. Redan under 80-talet kunde man konstatera att ubåtarna hade blivit så tysta att passiv detektering inte räckte till varför intresset istället riktades mot primärt aktiva system. Aktiv sändning medför sina egna nackdelar och tillsammans med de tekniker som utvecklats för att dämpa ekona från en ubåt gör att inte ens en aktiv, monostatisk sonar alltid ger tillfredsställande resultat. Till Försvarsmaktens nya medeltunga helikopter HKP14 har ett nytt sonarsystem införskaffats med möjlighet till fusionerad signalbehandling (s.k. multistatisk sonar) av signaler mottagna från flera olika mottagare såsom t.ex. sonarbojar.   Undersökningen syftar till att belysa vilka fördelar som kan erhållas vid helikopterbaserad, multistatisk ubåtsjakt och visar med ett antal räkneexempel bland annat att en större räckvidd och därmed även ett större detekteringsområde kan förväntas i en multistatisk konfiguration. Beräkningarna är gjorda med utgångspunkt i Uricks sonarekvationer men då faktorer såsom reverberation och kanalutbredning har avgränsats bort är det osäkert hur väl dessa resultat skulle stämma överens med en fältstudie. Utifrån de typfall som har undersökts visar emellertid studien på att de teoretiska fördelarna med ett multistatiskt system är tydliga och att dessa rent logiskt i viss utsträckning även borde gälla i praktiken. / The fact that submarines are becoming more silent and therefore harder to detect has led to an ever-increasing demand for more sensitive and sophisticated sensors to keep up with this development. As early as the 1980s it became obvious that submarines had become so silent that passive detection was not enough and the focus shifted toward active systems instead. Active transmission has its own disadvantages, and new techniques to silence submarines and reduce their acoustic signature even further have led to a situation where not even active, monostatic sonar always produces a satisfactory result. Along with the new medium sized helicopter (NH90), the Swedish Armed Forces have purchased a new sonar system that allows fused signal processing, using signals received by different receivers, such as sonobuoys. The aim of the study is to show what advantages can be gained from helicopter-based multistatic anti-submarine warfare and to show, by a number of arithmetic examples, that greater detection ranges and thus greater detection areas can be expected from a multistatic configuration. The examples are based on Urick’s sonar equations, but since factors such as reverberation and channel propagation of sound have been excluded from the study, it is uncertain how these results would compare to a field study. However, the study clearly shows the theoretical advantages of a multistatic system and that, on the basis of simple logic, these results should be feasible, to some extent, in practice.

OLIVEIRA, Frederico Inácio Costa de. Avaliação de genótipos de meloeiro quanto à resistência à mosca minadora. 2014. 54 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Programa de Pós-Graduação em Agronomia / Fitotecnia, Fortaleza-CE, 2014 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-19T13:05:24Z No. of bitstreams: 1 2014_dis_ficoliveira.pdf: 1387035 bytes, checksum: 44e7b3326944ccdacf271e37e21eb784 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-08-19T13:05:34Z (GMT) No. of bitstreams: 1 2014_dis_ficoliveira.pdf: 1387035 bytes, checksum: 44e7b3326944ccdacf271e37e21eb784 (MD5) / Made available in DSpace on 2016-08-19T13:05:34Z (GMT). No. of bitstreams: 1 2014_dis_ficoliveira.pdf: 1387035 bytes, checksum: 44e7b3326944ccdacf271e37e21eb784 (MD5) Previous issue date: 2014 / The melon (Cucumis melo L.) is one of the most important vegetables in the world. Given its peculiarities, as its short cycle and staggered planting, pest control culture is prejudiced, being spent every year large amounts of pesticides to control the miner fly (Liriomyza sativae Blanchard) in melon, which, since 2000, appears as the key pest. The genetic control among the control measures is the ideal medium to circumvent the damage caused by this insect alternative. Thus, the aim of this work to evaluate a collection of Cucumis melo L. germplasm for resistance to miner fly (Liriomyza sativae); resistant accessions to identify and correlate the variables within and between experiments and field cage in field and cage were tested 58 melon genotypes for resistance to leaf miner, 49 accesses the Active Germplasm Bank of melon Embrapa Vegetables, five accessions of the Germplasm Bank of Cucurbits for the Brazilian Northeast and four commercial hybrids. The work was divided into two experiments: field and cage. The field experiment was conducted at the Experimental Station of Pacajus – CE, of the Embrapa Tropical Agroindustry (CNPAT), from December 2012 to February 2013 in a completely randomized design with two replications and six plants per plot. The experiment was conducted in cages in the Laboratories of Entomology and of Plant Breeding and Genetic Resources, in Fortaleza, during the period March 2013 to ammonium in a completely randomized design with six replications, each plant, subjective score based on infestation and number of mines per leaf - in the field: a portion of the following characteristics were evaluated and cage - number of mines per leaf chlorophyll content of leaves and colorimetry. Data were submitted to Kruskal-Wallis test. To determine the degree of relationship between variables, we calculated the Pearson correlation coefficient. The results revealed statistically significant differences among accessions for all variables. Genotypes 16, 48 and 51 showed favorable results for resistance in both experiments, so are best suited for future research focusing on improving introgression of resistance in melon L. sativae. / O meloeiro (Cucumis melo L.) é uma das hortaliças de maior relevância no mundo. Dada suas peculiaridades, como seu ciclo curto e plantio escalonado, o controle fitossanitário da cultura é prejudicado, sendo gasto todos os anos grande volume de defensivos agrícolas para controlar a mosca minadora (Liriomyza sativae Blanchard) no meloeiro, que, desde 2000, aparece como a praga chave da cultura. O controle genético, dentre as medidas de controle, é a alternativa ideal para contornar os danos causados por esse inseto. Com isso, objetivou-se com esse trabalho: Avaliar uma coleção de germoplasma de Cucumis melo L. quanto à resistência à mosca minadora (Liriomyza sativae); identificar acessos resistentes e correlacionar as variáveis analisadas dentro e entre os experimentos de campo e de gaiola.. Foram testados, em campo e em gaiola, 58 genótipos de meloeiro quanto a resistência à mosca minadora, sendo 49 acessos do Banco Ativo de Germoplasma de Melão da Embrapa Hortaliças (Brasília-DF), cinco acessos do Banco de Germoplasma de Cucurbitáceas para o Nordeste Brasileiro e quatro híbridos comerciais. O trabalho foi dividido em dois experimentos: campo e gaiola. O experimento de campo foi realizado no Campo Experimental de Pacajus-CE da Embrapa Agroindústria Tropical (CNPAT), no período de dezembro de 2012 a fevereiro de 2013, em um delineamento inteiramente casualizado, com duas repetições e seis plantas por parcela. O experimento nas gaiolas foi realizado nos laboratórios de Entomologia e de Melhoramento e Recursos Genéticos Vegetais da Embrapa Agroindústria Tropical, em Fortaleza-CE, durante o período de março a maio de 2013, em um delineamento inteiramente casualizado, com seis repetições, sendo cada planta uma parcela Foram avaliadas as seguintes características: no campo - nota subjetiva com base na infestação e número de minas por folha; e, em gaiola - número de minas por folha, teor de clorofila e colorimetria das folhas. Os dados foram submetidos ao teste de Kruskal-Wallis. Para determinar o grau de relação entre as variáveis estudadas, calculou-se o coeficiente de correlação de Pearson. Os resultados revelaram diferença estatística entre os acessos para todas as variáveis estudadas. Os genótipos CNPH 11-282, CNPH 11-1072 e CNPH 11-1077 apresentaram resultados favoráveis para resistência em ambos os experimentos, portanto são os mais indicados para pesquisas futuras em melhoramento com enfoque na introgressão da resistência à L. sativae em meloeiro.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-06-29T13:49:53Z No. of bitstreams: 1 Andresa Priscila Souza Ramos.pdf: 3687585 bytes, checksum: 03a2a3149474293923ca08c0db68bc60 (MD5) / Made available in DSpace on 2016-06-29T13:49:53Z (GMT). No. of bitstreams: 1 Andresa Priscila Souza Ramos.pdf: 3687585 bytes, checksum: 03a2a3149474293923ca08c0db68bc60 (MD5) Previous issue date: 2011-08-26 / The association between bacteria and plants is considered extremely important because it may promote the plant development by providing nutrients, protection, and production of plant growth promoting substances like indole acetic acid (IAA). The sugarcane production is under a great economic and agricultural importance, and increasing its production still depending on several chemical inputs that are expensive and environmentally damaging. A sustainable alternative is the use of beneficial bacteria that may diminish or abolish the use of these inputs and increase agricultural production. Therefore, the objectives of this study were: i) selecting and evaluating IAA producing bacteria, dependent and independent pathway of tryptophan, sugarcane roots plant association in crop fields in Pernambuco, ii) evaluate the influence of niche isolation, the place of cultivation, the cultivation time and host plant genotype on frequency and IAA-producing bacteria; iii) Analyze the genetic variability of IAA-producing bacteria by BOX-PCR, and iv) assess the noncultivable bacterial community sugarcane ratoon-associated v) Evaluate the production of IAA, two endophytic bacteria according to the time. Isolates were studied at four and ten months sugarcane plant cultivation, collected in EECAC Carpina-PE and Petribú factory,Lagoa de Itaenga-PE and isolates from three months on sugarcane plant-ratoon regrowth, collected in EECAC. The results showed that plants from sugarcane crop fields in Pernambuco have a high frequency of bacteria producing IAA in vitro by a tryptophan-dependent and independent pathways, the crop place, cultivation time of the host plant and niche colonization. Bacterial influence on the distribution of IAA-producing bacteria. In addition, the location, time of cultivation of the host plant genotype and bacterial niche colonization influenced the production levels. The strains showed high genetic variability. In sugarcane plant-ratoon, the bacterial population density was higher than in the rizhosphericsoil and root-endophytic bacteria also showed a high frequency capacity to produce IAA in vitro. Analysis of variability and genetic diversity revealed high genetic variability among bacteria producing IAA and the predominance of dominant bacterial groups not grown in soil and inside the roots of sugarcane plant-ratoon grown in Pernambuco. Some strains of root endophytic sugarcane plant, with capacity to produce IAA, were identified as belonging to the genus Enterobacter and Burkholderia / A associação entre bactérias benéficas e plantas é considerada extremamente importante, pois pode promover o desenvolvimento do vegetal através da disponibilização de nutrientes, proteção e produção de substâncias promotoras de crescimento vegetal, como o ácido indol acético (AIA). A canade- açúcar é uma cultura de grande importância agrícola e econômica, e sua produção crescente ainda depende de diversos insumos químicos que são onerosos e prejudicam o ambiente. Uma alternativa sustentável seria a utilização de bactérias benéficas que possam diminuir ou anular o uso desses insumos e incrementar a produção agrícola. Diante disso, os objetivos deste trabalho foram: i) selecionar e avaliar bactérias produtoras de AIA, via dependente e independente de triptofano, associadas a raízes de plantas de cana-de-açúcar cultivadas em Pernambuco; ii) avaliar a influência dos nichos de colonização, do local e tempo de cultivo e do genótipo da planta hospedeira sobre a frequência e produção de bactérias produtoras de AIA; iii) analisar a variabilidade genética de bactérias produtoras de AIA por BOX-PCR; iv) avaliar a comunidade bacteriana não cultivável associada a cana soca; v) e avaliar a produção de AIA, de duas bactérias endofíticas, em função do tempo. Foram estudadas bactérias isoladas aos quatro e dez meses de cultivo de cana planta, coletadas na EECAC- Carpina-PE e na Usina Petribú- Lagoa de Itaenga-PE e linhagens isoladas aos três meses de rebrota na cana soca, coletadas na EECAC. Os resultados demonstraram que as plantas de cana-deaçúcar cultivadas em Pernambuco apresentam alta frequência de bactérias com capacidade de produzir AIA in vitro, via dependente e independente de triptofano, e que o local, tempo de cultivo da planta hospedeira e o nicho de colonização bacteriana influenciaram na distribuição das bactérias produtoras de AIA. Além disso, o local, tempo de cultivo, genótipo da planta hospedeira e o nicho de colonização bacteriana influenciaram nos níveis de produção e as linhagens apresentaram alta variabilidade genética. Na cana soca, a densidade populacional bacteriana foi maior no solo rizosférico do que endofítica de raiz e também apresentaram alta frequência de bactérias com capacidade de produzir AIA in vitro. A análise da variabilidade e diversidade genética revelaram alta variabilidade genética entre as bactérias produtoras de AIA e a predominância de grupos bacterianos dominantes, não cultivados, no solo e no interior das raízes de cana soca, cultivadas em Pernambuco. Algumas linhagens endofíticas de raiz de cana planta, com capacidade de produzir AIA, foram identificadas como pertencentes aos gêneros Burkholderia e Enterobacter

Made available in DSpace on 2014-08-20T13:44:50Z (GMT). No. of bitstreams: 1 dissertacao_blanca_acuna_idrogo.pdf: 2513627 bytes, checksum: 04a4e68c1763a9929f1a4cfa61b1b413 (MD5) Previous issue date: 2009-10-17 / The present reseaech paper was made in the District,Province and Region Lambayeque located in northern Perú during the agricultura seasons: 2004-2005, 2005- 2007 and 2006-2007. The objetive was to evaluate the entomo fauna behavior and the This research work is run in the District, Province and Region Lambayeque, Peru during the crop season 2004-2005, 2005-2006 and 2006 - 2007 with the objective of evaluating the behavior of the entomofauna and yield potential native cotton (Gossypium barbadense L Ssp. Peruvianum).) cotton called "country". The crop was installed in June 2004 beginning with a nursery, in an area corresponding to Ferreñafe Sican Museum and its final installation in the field of Sipan Museum in Lambayeque, at an altitude of 29 meters, average temperature 22.5 º C, humidity on 75% and an average rainfall of 24 mm. 1.333 plants were installed. Also served to assess the ecotypes of color, material valued for its natural color, with a genetic resource of great value to work rescuing this poor germplasm, which is in danger of extisiòn due to the introduction of commercial hybrid , that would put in risk so precious ancestral legacy. We found significant genetic variation in all attributes evaluated. Ferreñafe province had the highest genetic variability in fiber color, the colored ecotypes present five out of nine. The most critical phases of pest attack were sprouting, fruiting and capsule opening. There was a low infestation of worm borer leaf Bucculatrix thurberiella, "Arrebiatadas" Dysdercus peruvianus "Peruvian beaked" Anthonomus vestitus and "wart mite" Acaliptus gossypii, mainly due to unsuitable conditions for their development. The native cotton crop will be greatly affected by the attack of pests if not done an adequate integrated pest management. The more promising ecotypes were: Orange-face, Fine red, white and pink White simple, 2903, 1880, 1642 and 1.24 kilos per plant, respectively. For weight of weed, highlights the ecotypes: Fine Colorado Claro Fifo 3.95 to 2.96 g, respectively, was found in the first harvest of the arboretum A , a greater number of fruit branches with 43,797 branches, with respect to the soca harvest, which formed only 10,643 fruit branches. In the arboretum "B", the results were the same trend. Sample sizes were adequate and representative of the population. The data had a normal or approximately normal distribution. / El presente trabajo de investigación se ejecutó en el Distrito, Provincia y Región Lambayeque-Perú, durante las campañas agrícola 2004-2005, 2005-2006 y 2006- 2007 con el objetivo de evaluar, el comportamiento de la entomofauna y el potencial de rendimiento de algodones nativos (Gossypium barbadense L. Ssp. Peruvianum) , denominado algodón del país . El cultivo se instaló en Junio 2004 iniciándose con un vivero, en un área correspondiente al Museo Sicán de Ferreñafe y su instalación definitiva en el ámbito del Museo de Sipán, en Lambayeque. Se instalaron 1,333 plantones. Además sirvió para evaluar los ecotipos de color, material valioso por su coloración natural, siendo un recurso genético de gran valor para trabajos de rescate de este escaso germoplasma, que se encuentra en peligro de extinción debido a la introducción de híbridos comerciales y cultivares transgénicos, que pondrían en riesgo tan preciado legado ancestral. Se encontró variabilidad genética significativa en todos los atributos evaluados. La provincia de Ferreñafe presentó la mayor variabilidad genética en color de fibra, al presentar cinco ecotipos coloreados de un total de nueve. Las fases más críticas para el ataque de plagas fueron en brotamiento, fructificación y apertura de cápsulas. El cultivo de algodón nativo se verá muy afectado por el ataque de plagas si no se realiza un adecuado manejo integrado de plagas. Los ecotipos más rendidores fueron: Anaranjado-Ante, fino colorado, blanco rosáceo y blanco simple, con 2.903, 1.880, 1.642 y 1.24 kilogramos por planta, respectivamente. Para peso de mota, sobresalieron los ecotipos: Fino colorado y fifo claro con 3.95 a 2.96 g, respectivamente, se encontró en la primera cosecha del arboretum A , en mayor número de ramas fruteras con 43.797 ramas, con respecto a la cosecha soca , que solo formó 10.643 ramas fruteras. En el arboretum B , los resultados tuvieron la misma tendencia.

In this episode, we take a quick walkthrough of the specific Tennessee Academic Standards for Social Studies as they relate to social studies teaching and learning in grades K-5. We discuss where you can find the standards, how they are organized, the role of the SSP (Social Studies Practices) standards for K-2 & 3-5, and explore topics and content standards progressively found in each grade level. / https://dc.etsu.edu/social-studies-education-oer/1002/thumbnail.jpg

Climate change and socio-economic development are greatly affecting the quality of freshwater, especially the excessive accumulation of nutrients (N and P), which eventually leads to the occurrence of eutrophication. Lake Vomb is one of the main sources of drinking water in southern Sweden and the nutrient load from the catchment makes it a eutrophic lake with recurring algal blooms. This project developed a hydrological model by Soil and Water Assessment Tool (SWAT) to model the impact of climate and socio-economic changes on nutrient dynamics on Lake Vomb. Two combinations of future scenarios were selected as combinations of Representative Concentration Pathways (RCP) and Shared Socioeconomic Pathways (SSP): 1) SSP1/RCP4.5 and 2) SSP5/RCP8.5. For the calibration and validation period, satisfactory results were obtained for monthly flow (R2 and NSE were 0.92 and 0.82, respectively) and yearly nutrient load simulation obtained overall convincing results (R2, NSE and PBIAS were 0.67, 0, 17% for total nitrogen (TN) and 0.78, -0.11, -1% for total phosphorus (TP) at the main inflow and R2, NSE and PBIAS were 0.46, 0.27, 15% for TN and 0.62, -0.01, -0.06% for TP at the second inflow). Simulation results of increased future flow scenarios showed higher peaks under the RCP8.5 scenario than under RCP4.5. Also, there was an increasing trend that flow will continuously rise during the simulation period. Results from future nutrient load simulation showed that the TN load was below the baseline in most scenarios and the TP load was all above the baseline. Besides, nutrient loading is more sensitive to the combination of SSPs and RCPs and got the highest loads under RCP4.5/SSP1. The challenge of reducing nutrient load increases over time, especially for P because the simulated load was higher for 2090-2100 than the load for 2040-2050. This project has limitations such as uncertain agriculture activities input and nutrient observations. This project provides projections of flows and nutrient loads into Lake Vomb for a combination of possible future scenarios and more different scenarios such as different RCPs and different designed SSPs deserve to be studied in the future.

To understand more about the neural underpinnings for leading and following is the driving force behind this thesis. To do so, there is a need to study leading and following on a basic level. For study I, an fMRI study of neuronal reactivity during leading and following, a minimal model was developed to study leader and follower behavior in a standardized way. This model uses finger tapping of rhythms representing the core of the interactions during leading and following. Participants are invited to both lead and follow, and no expertise is expected. The status difference between the leader and follower is not a part of the model. Data collection is made in Japan, and most of the analyses are carried out in Sweden. In study II the Swedish Universities Scales of Personality is translated from Swedish to Japanese. Personality can be described as a crucial feature in a person’s social and emotional functioning; they are relatively stable over the course of a lifetime. Three dimensions representing personality facets probably relevant for leading and following are emotional stability, extraversion, and agreeableness. Study II resulted in SSPJ-11 with eleven reliable personality scales representing theses three facets relevant for leading and following. Study I presented an effective model to investigate leading and following during fMRI scanning. This model can be used with other designs for further brain imaging and behavior studies. From Study I, it became clear that the neuronal reactivation for leading and following largely overlap, with some specific differences in insular, temporal, and cerebellar reactivity. These results could be a first step towards a revealing the crucial components of neuro reactivations for leading and following.

Rice (Oryza sativa) is the staple food for more than 3.5 billion people worldwide. As the population continues to grow, rice yield will need to increase by 1% every year for the next 30 years to keep up with the growth. In the US, Arkansas accounts for more than 50% of rice production. Over the last 68 years, rice production has continued to grow in Mississippi, placing it in fourth place after Arkansas, Louisiana, and California. Due to increasing rice acreage, regionally and worldwide, the need to develop abiotic stress-tolerant rice has increased. Unfortunately, current rice breeding programs lack genetic diversity, and many traits have been lost through the domestication of cultivated rice. Currently, stressors stemming from the continued effects of climate change continue to impact rice. To counteract the impacts of climate change, research has shifted to evaluating wild and weedy relatives of rice to improve breeding techniques. Weedy rice (Oryza sativa ssp.) is a genetically similar, noxious weed in rice with increased competitive ability. Studies have demonstrated that weedy rice has increased genetic variability and inherent tolerance to abiotic stressors. The aims of this study were to 1) screen a weedy rice mini-germplasm for tolerance to cold, heat, and complete submergence-stress, 2) utilize simple sequence repeat (SSR) markers and single nucleotide polymorphisms to evaluate the genetic diversity of the weedy rice population, and 3) use genome-wide association (GWAS) to identify SNPs associated with candidate genes within the population.

Tesis por compendio / [EN] Practical experience in software engineering has demonstrated that the goal of building totally fault-free software systems, although desirable, is impossible to achieve. Therefore, it is necessary to incorporate mitigation techniques in the deployed software, in order to reduce the impact of latent faults. This thesis makes contributions to three memory corruption mitigation techniques: the stack smashing protector (SSP), address space layout randomisation (ASLR) and automatic software diversification. The SSP is a very effective protection technique used against stack buffer overflows, but it is prone to brute force attacks, particularly the dangerous byte-for-byte attack. A novel modification, named RenewSSP, has been proposed which eliminates brute force attacks, can be used in a completely transparent way with existing software and has negligible overheads. There are two different kinds of application for which RenewSSP is especially beneficial: networking servers (tested in Apache) and application launchers (tested on Android). ASLR is a generic concept with multiple designs and implementations. In this thesis, the two most relevant ASLR implementations of Linux have been analysed (Vanilla Linux and PaX patch), and several weaknesses have been found. Taking into account technological improvements in execution support (compilers and libraries), a new ASLR design has been proposed, named ASLR-NG, which maximises entropy, effectively addresses the fragmentation issue and removes a number of identified weaknesses. Furthermore, ASLR-NG is transparent to applications, in that it preserves binary code compatibility and does not add overheads. ASLR-NG has been implemented as a patch to the Linux kernel 4.1. Software diversification is a technique that covers a wide range of faults, including memory errors. The main problem is how to create variants, i.e. programs which have identical behaviours on normal inputs but where faults manifest differently. A novel form of automatic variant generation has been proposed, using multiple cross-compiler suites and processor emulators. One of the main goals of this thesis is to create applicable results. Therefore, I have placed particular emphasis on the development of real prototypes in parallel with the theoretical study. The results of this thesis are directly applicable to real systems; in fact, some of the results have already been included in real-world products. / [ES] La creación de software supone uno de los retos más complejos para el ser humano ya que requiere un alto grado de abstracción. Aunque se ha avanzado mucho en las metodologías para la prevención de los fallos software, es patente que el software resultante dista mucho de ser confiable, y debemos asumir que el software que se produce no está libre de fallos. Dada la imposibilidad de diseñar o implementar sistemas libres de fallos, es necesario incorporar técnicas de mitigación de errores para mejorar la seguridad. La presente tesis realiza aportaciones en tres de las principales técnicas de mitigación de errores de corrupción de memoria: Stack Smashing Protector (SSP), Address Space Layout Randomisation (ASLR) y Automatic Software Diversification. SSP es una técnica de protección muy efectiva contra ataques de desbordamiento de buffer en pila, pero es sensible a ataques de fuerza bruta, en particular al peligroso ataque denominado byte-for-byte. Se ha propuesto una novedosa modificación del SSP, llamada RenewSSP, la cual elimina los ataques de fuerza bruta. Puede ser usada de manera completamente transparente con los programas existentes sin introducir sobrecarga. El RenewSSP es especialmente beneficioso en dos áreas de aplicación: Servidores de red (probado en Apache) y lanzadores de aplicaciones eficientes (probado en Android). ASLR es un concepto genérico, del cual hay multitud de diseños e implementaciones. Se han analizado las dos implementaciones más relevantes de Linux (Vanilla Linux y PaX patch), encontrándose en ambas tanto debilidades como elementos mejorables. Teniendo en cuenta las mejoras tecnológicas en el soporte a la ejecución (compiladores y librerías), se ha propuesto un nuevo diseño del ASLR, llamado ASLR-NG, el cual: maximiza la entropía, soluciona el problema de la fragmentación y elimina las debilidades encontradas. Al igual que la solución propuesta para el SSP, la nueva propuesta de ASLR es transparente para las aplicaciones y compatible a nivel binario sin introducir sobrecarga. ASLR-NG ha sido implementado como un parche del núcleo de Linux para la versión 4.1. La diversificación software es una técnica que cubre una amplia gama de fallos, incluidos los errores de memoria. La principal dificultad para aplicar esta técnica radica en la generación de las "variantes", que son programas que tienen un comportamiento idéntico entre ellos ante entradas normales, pero tienen un comportamiento diferenciado en presencia de entradas anormales. Se ha propuesto una novedosa forma de generar variantes de forma automática a partir de un mismo código fuente, empleando la emulación de sistemas. Una de las máximas de esta investigación ha sido la aplicabilidad de los resultados, por lo que se ha hecho especial hincapié en el desarrollo de prototipos sobre sistemas reales a la par que se llevaba a cabo el estudio teórico. Como resultado, las propuestas de esta tesis son directamente aplicables a sistemas reales, algunas de ellas ya están siendo explotadas en la práctica. / [CA] La creació de programari suposa un dels reptes més complexos per al ser humà ja que requerix un alt grau d'abstracció. Encara que s'ha avançat molt en les metodologies per a la prevenció de les fallades de programari, és palès que el programari resultant dista molt de ser confiable, i hem d'assumir que el programari que es produïx no està lliure de fallades. Donada la impossibilitat de dissenyar o implementar sistemes lliures de fallades, és necessari incorporar tècniques de mitigació d'errors per a millorar la seguretat. La present tesi realitza aportacions en tres de les principals tècniques de mitigació d'errors de corrupció de memòria: Stack Smashing Protector (SSP), Address Space Layout Randomisation (ASLR) i Automatic Software Diversification. SSP és una tècnica de protecció molt efectiva contra atacs de desbordament de buffer en pila, però és sensible a atacs de força bruta, en particular al perillós atac denominat byte-for-byte. S'ha proposat una nova modificació del SSP, RenewSSP, la qual elimina els atacs de força bruta. Pot ser usada de manera completament transparent amb els programes existents sense introduir sobrecàrrega. El RenewSSP és especialment beneficiós en dos àrees d'aplicació: servidors de xarxa (provat en Apache) i llançadors d'aplicacions eficients (provat en Android). ASLR és un concepte genèric, del qual hi ha multitud de dissenys i implementacions. S'han analitzat les dos implementacions més rellevants de Linux (Vanilla Linux i PaX patch), trobant-se en ambdues tant debilitats com elements millorables. Tenint en compte les millores tecnològiques en el suport a l'execució (compiladors i llibreries), s'ha proposat un nou disseny de l'ASLR: ASLR-NG, el qual, maximitza l'entropia, soluciona el problema de la fragmentació i elimina les debilitats trobades. Igual que la solució proposada per al SSP, la nova proposta d'ASLR és transparent per a les aplicacions i compatible a nivell binari sense introduir sobrecàrrega. ASLR-NG ha sigut implementat com un pedaç del nucli de Linux per a la versió 4.1. La diversificació de programari és una tècnica que cobrix una àmplia gamma de fa\-llades, inclosos els errors de memòria. La principal dificultat per a aplicar esta tècnica radica en la generació de les "variants", que són programes que tenen un comportament idèntic entre ells davant d'entrades normals, però tenen un comportament diferenciat en presència d'entrades anormals. S'ha proposat una nova forma de generar variants de forma automàtica a partir d'un mateix codi font, emprant l'emulació de sistemes. Una de les màximes d'esta investigació ha sigut l'aplicabilitat dels resultats, per la qual cosa s'ha fet especial insistència en el desenrotllament de prototips sobre sistemes reals al mateix temps que es duia a terme l'estudi teòric. Com a resultat, les propostes d'esta tesi són directament aplicables a sistemes reals, algunes d'elles ja estan sent explotades en la pràctica. / Marco Gisbert, H. (2015). Cyber-security protection techniques to mitigate memory errors exploitation [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/57806 / Compendio