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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.
11

Interaction Patterns and Web-Structures of Resonant Solitons of the Kadomtsev-Petviashvili Equation

Tippabhotla, Anupama 08 July 2005 (has links)
In this thesis, the interaction pattern for a class of soliton solutions of the Kadomtsev- Petviashvili (KP) equation (−4ut + uxxx + 6uux )x + 3uyy = 0 is analyzed. The complete asymptotic properties of the soliton solutions for y → ±∞ are determined. The resonance characteristic of two sub-classes of the soliton solutions, in which N- incoming line solitons for y → −∞ interact to form N+ outgoing line solitons for y → ∞, is described. These two specific sub-classes of (N-,N+)-soliton solutions are the following: 1) [(2, 3), (2, 4), (2, 5)], 2) [(3, 2), (3, 3), (3, 4)]. The intermediate solitons and the interaction regions of the above soliton solutions are determined, and their various interaction patterns are explored. Maple and Mathematica are used to get the 3 dimensional plots and contour plots of the soliton solutions to show their interaction patterns. Finally, the spider-web-structures of the discussed solitons of the KP equation are displayed.
12

Propiedades Optoelectrónicas de Nanocristales Semiconductores

Díaz García, José Gabriel 07 April 2005 (has links)
Los métodos kp y tight-binding, que inicialmente fueron diseñados para predecir las propiedades del sólido extendido, han sido adaptados para describir las propiedades optoelectrónicas de nanoestructuras semiconductoras. El Hamiltoniano kp de 4 bandas para huecos y la ecuación de masa efectiva en el modelo de 1 banda para electrones se han discretizado en coordenadas cilíndricas, con el objetivo de estudiar los efectos de la aplicación de un campo magnético sobre el espectro energético de los nanocristales y las propiedades colectivas en sistemas de puntos cuánticos acoplados. Entre los resultados obtenidos cabe destacar que el acoplamiento entre nanocristales con topología de antidot provoca una importante estabilización energética de la minibanda fundamental, la cual permanece inalterada frente a la acción de un campo magnético.El modelo tight-binding de primeros vecinos que se ha implementado utiliza una base sp3s* para describir cada átomo del nanocristal. Este modelo atomista permite la descripción detallada de la estructura óptica fina de los nanocristales. Se ha evidenciado que los espectros teóricos de absorción con luz polarizada en la dirección z permiten discriminar entre geometrías que la microscopía electrónica no es capaz de discernir.
13

Adaptive inverse modeling of a shape memory alloy wire actuator and tracking control with the model

Koh, Bong Su 02 June 2009 (has links)
It is well known that the Preisach model is useful to approximate the effect of hysteresis behavior in smart materials, such as piezoactuators and Shape Memory Alloy(SMA) wire actuators. For tracking control, many researchers estimate a Preisach model and then compute its inverse model for hysteresis compensation. However, the inverse of its hysteresis behavior also shows hysteresis behavior. From this idea, the inverse model with Kransnoselskii-Pokrovskii(KP) model, a developed version of Preisach model, can be used directly for SMA position control and avoid the inverse operation. Also, we propose another method for the tracking control by approximating the inverse model using an orthogonal polynomial network. To estimate and update the weight parameters in both inverse models, a gradient-based learning algorithm is used. Finally, for the SMA position control, PID controller, adaptive controllers with KP model and adaptive nonlinear inverse model controller are compared experimentally.
14

Modeling Rogue Waves with the Kadomtsev-Petviashvili Equation

Wanye, Randy Kanyiri Unknown Date
No description available.
15

Två kommunistiska partier i Sverige : Finns det någon ideologisk skillnad mellan SKP och KP?

Norén Carlsson, Christoffer January 2015 (has links)
This essay examines two communist parties in Sweden; The Communist Party (Kommunistiska partiet [KP]) and Sweden's Communist party (Sveriges kommunistiska parti [SKP]). Furthermore, this essay is a comparative study where the two parties' political agendas are compared. The method with which the study was conducted is a quantitative content analysis, where the frequencies of usage pertaining to certain words and expressions have been measured. The Communist Manifesto by Karl Marx has also been compared to these two parties' political agendas concerning words and expressions. This was done in order to determine which of the examined parties stands closer to the aforementioned original document from an ideological perspective. The result reveals which differences that were detected.
16

Detecção de mecanismos de resistência, propriedades adesivas e capacidade de formação de biofilmes de Klebsiella pneumoniae multirresistentes / Detection of mechanisms of resistance, adhesive properties and ability of multi-resistant Klebsiella pneumoniae to form biofilms

Wincker Neto, Carlos Hugo Del Priore 28 March 2013 (has links)
During the last decades, K. pneumoniae has emerged as one of the most clinically significant pathogens, especially due to the high prevalence of strains producing extended spectrum β-lactamases (ESBL) and carbapenemases. The therapeutic options to treat these infections are constrained not only by this enzyme production, but also by the regular ability to form biofilms. The development of K. pneumoniae biofilms on the host tissue eventually protect the microorganisms from the action of antimicrobial agents and from the immune response, apart from driving the expression of virulence factors. Thus, the aim of this study was to detect mechanisms of resistance, adhesive properties and ability of multi-resistant K. pneumoniae clinical isolates to form biofilms. In the first stage of the study, 33 strains of K. pneumoniae with reduced susceptibility to carbapenems were isolated. By using phenotypic tests, 10 samples positive for the modified Hodge test were detected, suggesting the production of carbapenemases, and 2 strains manifested positivity for the synergic test with boronic acid, suggesting the production of KPC. When employing molecular techniques, such as polymerase chain reaction, the gene blaKPC was not detected, characterizing failure on the phenotypic detection of KPC. In the second stage of the study, 14 strains of multi-resistant K. pneumoniae were analyzed in order to verify the ability of biofilm formation, as well as adhesive/aggregative properties. Most of the strains analyzed presented low affinity to p-xylene, suggesting hydrophilic character, aside from strong affinity to the basic solvent ethyl acetate indicating acidic surface characteristics. It was also verified that the strains studied manifested high ability of biofilm formation and important adhesion in epithelial cells. The combination of all the characteristics studied may contribute to the survival of K. pneumoniae in the host and in the environment, as the organization of microorganisms in biofilms complicates the pharmacological treatment and favors its spread and multi-resistance. / Durante as últimas décadas, a Klebsiella pneumoniae tem emergido como um dos patógenos mais importantes clinicamente, especialmente em função da alta prevalência de amostras produtoras de beta-lactamases de espectro estendido (ESBL) e carbapenemases. As opções terapêuticas para o tratamento destas infecções são limitadas não somente por esta produção enzimática, mas também pela frequente capacidade de formação de biofilmes. O estabelecimento de biofilmes de K. pneumoniae sobre tecidos do hospedeiro acaba por proteger os microrganismos da ação de agentes antimicrobianos e da resposta imunológica, além de conduzir a expressão de determinantes de virulência. Neste sentido, o objetivo deste trabalho foi detectar mecanismos de resistência, propriedades adesivas e capacidade de formação de biofilmes de isolados clínicos de K. pneumoniae multirresistentes. Na primeira fase deste estudo, foram isoladas 33 isolados clínicos de K. pneumoniae com perfil de sensibilidade reduzida aos carbapenêmicos. Através de testes fenotípicos foram detectadas 10 amostras que apresentaram positividade para o teste modificado de Hodge (MHT) sugerindo produção de carbapenemases e duas amostras que apresentaram positividade para o teste sinérgico com ácido borônico (AB), indicando produção de KPC (Klebsiella pneumoniae carbapenemase). Quando utilizado ferramentas moleculares, como a reação em cadeia da polymerase, não foi detectado o gene blaKPC, caracterizando desta forma uma falha na detecção fenotípica de KPC. Na segunda fase deste estudo, foram analisadas 14 amostras de K. pneumoniae multirresistentes a fim de verificar a capacidade de formação de biofilmes, bem como propriedades adesivas/agregativas. A maioria das isolados clínicos analisadas apresentaram baixa afinidade ao xileno, sugerindo um caráter hidrofílico, além de alta afinidade ao solvente básico acetato de etila indicando características superficiais ácidas. Foi verificado ainda que os isolados clínicos estudados apresentaram alta capacidade de formação de biofilme e importante adesão em células epiteliais. As combinações de todas estas características estudadas podem contribuir para a sobrevivência de K. pneumoniae no hospedeiro e no ambiente, pois a organização dos microrganismos em biofilme dificulta o tratamento farmacológico e favorece a sua disseminação e multirresistência.
17

Návrh letounu pro zástavbu hybridní pohonné jednotky / Aircraft design for the installation of a hybrid powerplant

Kapoun, Tomáš January 2015 (has links)
The master‘s thesis "Aircraft design for the installation of a hybrid powerplant" is focused on the design of the airplane suitable for hybrid powerplant. At the same time it is also deal with the most suitable location of the components necessary for this powerplant. These components are: a combustion engine, electric motor, gearbox and bed engine. Part of the master thesis is application-mount designed components: location and number of containers with batteries, a proposal for a new engine bed suitable for a hybrid powerplant. In the sub - section of the thesis is made a simple calculation of the economic return on investment from the perspective of the end-user aircraft with a hybrid powerplant.
18

High Resolution Wind Retrieval for SeaWinds on QuikSCAT

Luke, Jeremy Blaine 30 May 2003 (has links) (PDF)
An algorithm has been developed that enables improved the resolution wind estimates from SeaWinds data. This thesis presents the development of three key portions of the high resolution wind retrieval algorithm: Compositing individual σ-0 measurements and Kp, Retrieved wind bias correction, and ambiguity selection for high resolution winds. The high resolution winds produced by this algorithm are expected to become a useful resource for scientists and engineers studying the ocean winds. The high resolution wind retrieval algorithm allows wind to be retrieved much closer to land than is available from the low resolution winds estimated from the same scatterometer by the Jet Propulsion Laboratory. The high resolution winds allow features such as the eye of hurricanes to be seen with much greater detail than was previously possible.
19

High performance simulations of kernel P systems

Bakir, M.E., Konur, Savas, Gheorghe, Marian, Niculescu, I.M., Ipate, F. January 2014 (has links)
No / The paper presents the use of a membrane computing model for specifying a synthetic biology pulse generator example and discusses some simulation results produced by the tools associated with this model and compare their performances. The results show the potential of the simulation approach over the other analysis tools like model checkers.
20

A SYSTEMATIC REVIEW OF ATTRIBUTE-BASED ENCRYPTION FOR SECURE DATA SHARING IN IoT ENVIRONMENT.

Onwumere, Faith Nnenna January 2023 (has links)
Internet of Things (IoT) refers to a network of global and interrelated computing devices that connects humans and machines. It connects anything that has access to the internet and creates an avenue for data and information exchange. Devices within the IoT environment are embedded with processors, sensors and communication hardware that helps these devices collate data, analyze data (when needed), and transfer data amongst themselves. Even with the existence of IoT in making things easier for users and with the introduction of newer variants of IoT, several security and privacy challenges are introduced. In the rapidly evolving landscape of the Internet of Things (IoT), ensuring secure data sharing has become a critical concern. Attribute-based encryption (ABE) has emerged as a promising cryptographic technique for addressing security challenges in IoT environments. Attribute-Based Encryption (ABE) is a cryptographic method that provides public key encryption and access control based on attributes allocated. ABE can be used to encrypt data transmitted between IoT devices and the cloud. In situations where several devices have to interact with each other (e.g., smart home interacting with the user’s hospital IoT system), an intranet of things is formed, and these data is stored in the cloud. ABE can serve as a secure means of transmitting this data since these devices already possess unique attributes that can grant users access control. In this thesis, we aim to present a systematic review of the Attribute-Based Encryption techniques specifically designed for secure data sharing in IoT environments. The objective of this review is to analyze and synthesize existing research, identify trends, and highlight key findings in the field. Therefore, the document survey is chosen as the research strategy. PRISMA framework is followed in searching the eligible literature in 5 databases (Springer, ACM Digital library, Google Scholar, IEEE, Research Gate, Research Square, and Science Direct), with a final set of 30 articles retrieved from ACM Digital Library, IEEE, and Science Direct, all included for analysis. The results show insights on the several ABE approaches used in implementing a secure data sharing framework with access control (which involves enforcing policies that help data owners determine who can and cannot access their data), data privacy (which involves measures taken to ensure that confidentiality, integrity, and availability of any shared data), and data security (which involves practices that help protect any form of shared data from unauthorized access, tamper, or disclosure) in IoT devices.

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