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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.
241

Eukaryotic diversity of miers valley hypoliths

Keriuscia Gokul, Jarishma January 2012 (has links)
>Magister Scientiae - MSc / The extreme conditions of Antarctic desert soils render this environment selective towards a diverse range of psychrotrophic microbial communities. Cracks and fissures in translucent quartz rocks permit an adequate amount of penetrating light, sufficient water and nutrients to support cryptic microbial development. Hypolithons colonizing the ventral surface of these quartz rocks have been classified into three types: cyanobacterial dominated (Type I),moss dominated (Type II) and lichenized (Type III) communities. Eukaryotic microbial communities were reported to represent only a minor fraction of Antarctic communities. In this study, culture independent techniques (DGGE, T-RFLP and clone library construction) were employed to determine the profile of the dominant eukaryotes, fungi and microalgae present in the three different hypolithic communities. The 18S rRNA gene (Euk for eukaryotes), internal transcribed spacer (ITS for fungi) and microalgal specific regions of the 18S rRNA gene, were the phylogenetic markers targeted for PCR amplification from hypolith metagenomic DNA. Results suggest that the three hypolith types are characterized by different eukaryotic, fungal and microalgal communities, as implied by nMDS analysis of the DGGE and T-RFLP profiles. Sequence analysis indicates close affiliation to members of Amoebozoa, Alveolata, Rhizaria (general eukaryote), Ascomycota (fungal) and Streptophyta (microalgal). Many of these clones may represent novel species. This study demonstrates that Dry Valley hypolithons harbour higher eukaryote diversity than previously recognised.Each hypolithon is colonized by specialized microbial communities with possible keystone species. The ecological role of the detected microorganisms in the hypolith environment is also theorized, and a trophic hierarchy postulated.
242

Defending against denial of service attacks in ETSI ITS-G5 networks / Försvar mot överbelastningsattacker hos ETSI ITS-G5 nätverk

Lind, Oskar January 2020 (has links)
This thesis explores the combined subjects of keep alive forwarding, denial of service attacks and decentralized congestion control. In a society where the technical requirements on vehicles constantly escalate; inter-vehicle communication has risen as a potential springboard for new technologies. The ETSI ITS-G5 standard is a vehicular ad-hoc network standard that offers manufacturers the possibility to include a feature called keep alive forwarding. This feature lets the nodes forward messages on a pre-defined time interval even if the original broadcaster is no longer present. As this feature might provide exploits for potential people with malicious intent it has been evaluated how resilient the standard might be in such a situation. Also included in this thesis is the decentralized congestion control, a feature required by the standard. To evaluate these features a series of simulations has been performed where vehicles in a highway scenario have been exposed to a denial of service attack where the attacker uses the keep-alive forwarding as an exploit. The findings are that decentralized congestion control does mitigate some of the direct consequences of such an attack. Although it does not eliminate these entirely and new problems are introduced. Finally, alternative methods to perform keep alive forwarding are suggested to enhance this feature.
243

Molecular Detection and Quantification of the Fish Pathogen <i>Saprolegnia</i> spp. Using qPCR and Loop Mediated Isothermal Amplification

Ghosh, Satyaki 03 December 2019 (has links)
No description available.
244

Early Empirical Evidence for the Effects of Adaptive Ramp Metering on Measures of Travel Time Reliability

Low, Travis Charles 01 September 2017 (has links)
Adaptive ramp metering (ARM) is a critical component of smart freeway corridors under an active traffic management portfolio. While improving capacity through smart corridors and application of proactive traffic management solutions is less costly and easier to deploy than freeway widening, conversion to smart corridors still represents a sizable investment for a state department of transportation. Early evidence of improvements following these projects can be valuable to agencies. However, in the U.S. there have been limited evaluations, of smart corridors in general and ARM in particular, based on real operational data. This thesis explores travel time reliability measures for the eastbound (EB) Interstate 80 (I-80) corridor in the San Francisco Bay Area before and after implementation of ARM using INRIX data. These measures include buffer index, planning time, and measures from the literature that account for both skew and width of the travel time distribution. The measures are estimated for the entire corridor as well as corridor segments upstream of a bottleneck that historically have the worst measures of reliability. A new metric for measuring unreliability that may be derived from readily available INRIX data is also proposed in the thesis using data from the study corridor. While the ARM system is relatively new, the results indicate positive trends in measures of reliability even as the number of incidents on the corridor has increased in line with the national crash trends. The spatio-temporal trend evaluation framework used here may be used in the future to obtain more robust conclusions. However, since multiple smart corridor components were installed simultaneously, it may not be possible to fully isolate the effects of the ARM, or any of the other systems, individually.
245

Evoluce pohlavních chromozomů a karyotypů hadů / Evolution of sex chromosomes and karyotypes in snakes

Augstenová, Barbora January 2017 (has links)
Snakes (Serpentes) are a group of squamate reptiles (Squamata) including more than 3600 species. The vast majority of snakes are from the group Caenophidia, which includes approximately 90% of all extant snake species and represents the most studied lineage. Squamate reptiles are variable in sex determination and genome organisation, however, caenophidian snakes are quite stable in these respects. The typical - and probably ancestral - snake karyotype is composed of 36 chromosomes with 16 macro- and 20 microchromosomes. In all snake species, genotypic sex determination (GSD) is expected and it was assumed until recently that all snakes possessed ZZ/ZW sex chromosomes. The main reason for this is that most of the studied snakes were from the group Caenophidia and in the rest of the snake lineages it was believed that their sex chromosomes were homologous. In fact, the sex chromosomes of non-caenophidian snakes have not yet been identified - with the single exception of Acrantophis dumerili. Nevertheless, a recent study showed that there was an independent evolution of XX/XY sex chromosomes in pythons and boas. Sex chromosomes of these snakes are homomorphic and so far they have not been detected by classical cytogenetic methods. In this context, the aim of this study is to explore whether it is...
246

Systematika rodu Ramariopsis (Basidiomycota, Clavariaceae) ve střední Evropě / Systematics of the genus Ramariopsis (Basidiomycota, Clavariaceae) in central Europe

Matouš, Jan January 2017 (has links)
The genus Ramariopsis (Clavariaceae, Agaricales) having ramarioid, rarely clavarioid basidiomata includes about 15 species in central Europe. They are probably saprotrophic species which usually occur in grasslands or rarely open places in shrubs or deciduous forests. In this work, 88 collections of this genus mainly from the Czech Republic and Slovakia were studied, of which 57 sequences from the LSU and 36 from the ITS regions of the nuclear ribosomal RNA gene complex were obtained. Based on molecular-phylogenetic analyses using the maximum likelihood and bayesian methods, phylogenetic trees were created showing 16 well-supported clades. So detailed study on the phylogeny and relationships among species of the genus Ramariopsis is presented for first time, even within the world literature. Subsequent morphological analysis supported by SEM study of basidiospores showed that obtained clades represent nine species known in taxonomic literature, three so far non-described species (that were labelled with provisional names) and four clades whose interpretation is uncertain at the moment. Thus, seven clades represent cryptic diversity, which is a rather high extent. A new species Ramariopsis robusta Matouš et Holec has already been published and Ramariopsis rufipes and Ramariopsis kunzei var. bispora...
247

Ukládání trestů dospělým / Imposing punishments on adults

Nechanická, Kristýna January 2020 (has links)
Imposing punishments on adults Abstract My diploma thesis deals with the issue of imposing punishments on adult persons. This thesis attempts to cover a very broad range of issues related to the topic and to provide readers with a clear and comprehensive overview. For this purpose, this thesis is presented in four main consecutive parts, each divided into several subchapters. The first chapter briefly introduces the history of punishment and the individual historical criminal codes used in the area of the present-day Czech Republic from 1787 to now. The second chapter begins with a definition of punishment. This term is closely associated with the purpose of punishment, which is harder to define due to the lack of a clear definition in currently applicable legislation. This is why this chapter also deals with the theory of punishment and its purpose. The cornerstone of this thesis comprises the explanation of the main principles governing the imposition of punishment that is provided in the third chapter. This part is rather extensive in scope as it explains general principles, determining the type and the scope of punishment, as well as mitigating and aggravating circumstances and the closely related exclusion of double punishment. Given the current circumstances, I also touched upon punishments imposed...
248

Middleware for adaptive network connectivity

Waltersson, Roland January 2006 (has links)
As the coverage of modern wireless technologies expands, today’s mobile phones and PDAs often have a range of heterogeneous networks to which they may connect. It would benefit mobile applications to use the network which best corresponds to its need. However, making the handovers between networks transparent to allow communication sessions to survive is not trivial as the TCP/IP suite, used by most networking applications today, was initially not designed with mobility in mind. A Vinnova founded research project at Saab (together with associates1) has found that it could prove advantageous to monitor network quality together with the application’s needs and make intelligent decisions regarding what network to use. An algorithm for network classification and evaluation has been proposed. This thesis examined prerequisites and methods for implementing adaptive network connectivity through transparent handovers for mobile devices, resulting in a tentative model to demonstrate the mentioned research results. The prototype, implemented as a user space middleware, utilizes UDP encapsulation and a per-packet basis link evaluation, resulting in small overhead and fast context adaptation. Link monitoring ensures that server and clients are constantly updated about network quality and availability. The prototype yielded transparent handovers between networks, with short handover delays, at the cost of reduced performance for fast networks. 1 Blekinge Institute of Technology, Swedish National Testing and Research Institute, and SwedishRoad Administration / Täckningen av trådlösa nätverk ökar konstant, och dagens mobiltelefoner och handdatorer har ofta ett antal olika nätverk de kan ansluta till. Det skulle vara fördelaktigt för mobila applikationer att använda det nätverk som bäst passar dess behov. Att göra övergångarna mellan dessa nätverk transparenta så att pågående kommmunikationssessioner kan fortgå är dock inte helt trivialt, då TCP/IP protokollen från början inte var tänkta för mobila enheter. Ett av Vinnova finansierat forskningsprojekt utfört på Saab med flera1 har undersökt möjligheterna att övervaka kvaliteten på olika trådlösa nätverk samt kraven från applikationerna, och med detta som grund utföra intelligenta beslut om vilket nätverk som ska utnyttjas. En algoritm för att utföra dessa beslut har också föreslagits. Detta examensarbete undersökte möjligheterna för att implementera adaptiv nätverksroaming genom transparenta övergångar för mobila enheter, och resulterade i en demonstrator, som även kan visa resultaten från den nämnda forskningen. Prototypen, implementerad som en "middleware", använder UDP tunnling och en per-paket nätverksutvärdering, vilket resulterade i liten overhead och snabb anpassning till nya kommunikationssituationer. En länkövervakare såg till att server och klienter alltid var uppdaterade om kvaliteten och tillgängligheten av olika nätverk. Prototypen gav totalt transparenta övergångar mellan nätverk med relativt korta fördröjningar, med nackdelen av viss reducerad prestanda för snabba nätverk. 1 Blekinges Tekniska Högskola, Sveriges Provnings – och Forskningsinstitut, samt Vägverket
249

Comparative Study of Connected Vehicle Simulators

Ahmed, Md Salman, Hoque, Mohammad Asadul, Pfeiffer, Phil 07 July 2016 (has links)
Contemporary studies of Intelligent Transportation Systems (ITS) use simulations of vehicular and communications traffic, due to the ethical and practical infeasibility of conducting experiments on real transportation networks. Different simulators have been developed for modeling real-time vehicular mobility and inter-vehicular communication under varying traffic and roadway conditions. While most model the effect of mobility on communications, only a few simulate the impact of inter-vehicular communication on vehicular mobility. None, moreover, are implemented as parallel or distributed frameworks: an essential requirement for the study of ITS applications in large-scale urban environments. As a starting point for developing such a framework, one contemporary simulator, VNetInetSim, was tested to determine its behavior under large loads. Testing determined that VNetInetSim's memory usage and execution time increase exponentially in the number of simulated vehicles while remaining relatively constant under increased communication traffic.
250

A Modeling Approach for Evaluating Network Impacts of Operational-Level Transportation Projects

Diekmann, Joshua James 26 May 2000 (has links)
This thesis presents the use of microscopic traffic simulation models to evaluate the effects of operational-level transportation projects such as ITS. A detailed framework outlining the construction and calibration of microscopic simulation models is provided, as well as the considerations that must be made when analyzing the outputs from these models. Two case studies are used to reinforce the concepts presented. In addition, these case studies give valuable insight for using the outlined approach under real-world conditions. The study indicates a promising future for the use of microsimulation models for the purpose of evaluating operational-level projects, as the theoretical framework of the models is sound, and the computational strategies used are feasible. There are, however, instances where simulation models do not presently model certain phenomena, or where simulation models are too computationally intensive. Comprehensive models that integrate microscopic simulation with land use planning and realistic predictions of human behavior, for instance, cannot practically be modeled in contemporary simulation packages. Other than these instances, the largest obstacles to using simulation packages were found to be the manpower required and the complexity of constructing a model. Continuing research efforts and increasing computer speeds are expected to resolve the former issues. Both of the latter concerns are alleviated by the approach presented herein. Within the approach framework detailed in this thesis, particular emphasis is given to the calibration aspects of constructing a microscopic simulation model. Like the simulation process as a whole, calibration is both an art and a science, and relies on sound engineering judgement rather than indiscriminate, formulaic processes. / Master of Science

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