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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.
71

Applications of monolithic fiber interferometers and actively controlled fibers

Rugeland, Patrik January 2013 (has links)
The objective of this thesis was to develop applications of monolithic fiber devices and actively controlled fibers. A special twin-core fiber known as a ‘Gemini’ fiber was used to construct equal arm-length fiber interferometers, impervious to temperature and mechanical perturbations. A broadband add/drop multiplexer was constructed by inscribing fiber Bragg gratings in the arms of a Gemini Mach-Zehnder interferometer. A broadband interferometric nanosecond switch was constructed from a micro-structured Gemini fiber with incorporated metal electrodes. Additionally, a Michelson fiber interferometer was built from an asymmetric twin-core fiber and used as a high-temperature sensor. While the device could be readily used to measure temperatures below 300 °C, an annealing process was required to extend the range up to 700 °C. The work included development, construction and evaluation of the components along with numerical simulations to estimate their behaviors and to understand the underlying processes. The thesis also explored the use of electrically controlled fibers for filtering in the microwave domain. An ultra-narrow phase-shifted fiber Bragg grating inscribed in a fiber with internal electrodes was used as a scanning filter to measure modulation frequencies applied to an optical carrier. A similar grating was used inside a dual-wavelength fiber laser cavity, to generated tunable microwave beat frequencies. The studied monolithic fiber interferometers and actively controlled fibers provide excellent building blocks in such varied field as in microwave photonics, telecommunications, sensors, and high-speed switching, and will allow for further applications in the future. / Syftet med denna avhandling var att utveckla tillämpningar av monolitiska fiber komponenter samt aktivt kontrollerbara fiber. En speciell tvillingkärnefiber, även kallad ’Geminifiber’ användes för att konstruera fiber interferometrar med identisk armlängd som ej påverkas av termiska och mekaniska variationer. En bredbanding utbytarmultiplexor konstruerades genom att skriva in fiber Bragg gitter inuti grenarna på en Gemini Mach-Zehnder interferometer. Geminifibrer med interna metallelektroder användes för att konstruera en bredbandig nanosekundsnabb interferometrisk fiberomkopplare. Därtill användes en tvillingkärnefiber som en hög-temperatursensor. Även om komponenten direkt kan användas upp till 300 °C, måste den värmebehandlas för att kunna användas upp till 700 °C. Arbetet har innefattat utveckling, konstruktion och utvärdering av komponenterna parallellt med numeriska simuleringar för att analysera deras beteenden samt få insikt om de underliggande fysikaliska processerna. Avhandlingen behandlar även tillämpningar av en elektriskt styrbar fiber för att filtrera radiofrekvenser. Ett ultrasmalt fasskiftat fiber Bragg gitter skrevs in i en fiber med interna elektroder och användes som ett svepande filter för att mäta modulationsfrekvensen på en optisk bärfrekvens. Ett liknande gitter användes inuti en laserkavitet för att generera två olika våglängder samtidigt. Dessa två våglängder användes sedan för att generera en svävningsfrekvens i mikrovågsbandet. De undersökta monolitiska fiberinterferometrarna och de aktivt styrbara fibrerna erbjuder en utmärkt byggsten inom så pass skiljda områden som Mikrovågsfotonik, Telekommunikation, Sensorer samt Höghastighets-omkopplare och bör kunna användas inom många olika tillämpningar i framtiden. / <p>QC 20130226</p>
72

Compact Matrix-Switch-Based Hierarchical Optical Path Cross-Connect with Colorless Waveband Add/Drop Ratio Restriction

MORIWAKI, Osamu, SATO, Ken-ichi, HASEGAWA, Hiroshi, ISHII, Kiyo, HIRAKO, Ryosuke 04 1900 (has links)
No description available.
73

The impact of dietary interventions on the promotion of the classroom health of foundation phase learners with ADD / Juanita Louw

Louw, Juanita January 2005 (has links)
The purpose of this study was to determine, by means of a review of literature and empirical research, the impact of dietary interventions on the classroom health promotion of Foundation Phase learners with ADD. In order to reach this goal, it was imperative to illustrate the meaning of the concepts health, wellness, health promoting schools, nutrition and Attention Deficit Disorder (ADD). The objective of the empirical research was to determine whether dietary interventions would promote the health of Foundation Phase learners with ADD in the classroom by focusing on decreasing their levels of hyperactivity, increasing their concentration and improving their social behaviour. In conclusion, the following are some of the findings of this study. Dietary interventions impacted positively on: the hyperactivity level of participating foundation phase learners with ADD in the classroom; the ability of participating foundation phase learners with ADD to concentrate in the classroom; and the social behaviour of participating foundation phase learners with ADD in the classroom. / Thesis (M.Ed.)--North-West University, Vaal Triangle Campus, 2005.
74

Children's Attention Deficit/Hyperactivity Disorder self-help books and the politics of correction

Gold, Rachel Sira 14 December 2007 (has links)
AD/HD is a prevalent medical diagnosis given to 3-7% of children in British Columbia. Since the diagnosis’ inception in 1902, children’s behaviour has been described in similar ways, but labels to define it have continuously changed, reflecting the diagnosis’ mutability and connection to shifting discourses of normativity. An analysis of moments in the text of 13 children’s self-help books illuminates that the process books refer to as correction is actually a disciplinary process exercised in children’s social relations, which guide them to act according to socially constructed notions of normative behaviour. I draw two conclusions from my research: (a) the correction of AD/HD-diagnosed children is a political process supported by a complex network of power relations and (b) diagnosed children’s lives are emmeshed in practices of disciplinary power that establish, and maintain, their state of being normalised.
75

Children's Attention Deficit/Hyperactivity Disorder self-help books and the politics of correction

Gold, Rachel Sira 14 December 2007 (has links)
AD/HD is a prevalent medical diagnosis given to 3-7% of children in British Columbia. Since the diagnosis’ inception in 1902, children’s behaviour has been described in similar ways, but labels to define it have continuously changed, reflecting the diagnosis’ mutability and connection to shifting discourses of normativity. An analysis of moments in the text of 13 children’s self-help books illuminates that the process books refer to as correction is actually a disciplinary process exercised in children’s social relations, which guide them to act according to socially constructed notions of normative behaviour. I draw two conclusions from my research: (a) the correction of AD/HD-diagnosed children is a political process supported by a complex network of power relations and (b) diagnosed children’s lives are emmeshed in practices of disciplinary power that establish, and maintain, their state of being normalised.
76

Edukace žáků se specifickými poruchami chování na I. stupni základní školy / Education of pupils with specific behavioral disorders at the first level of primary school

JANTAČOVÁ, Dominika January 2016 (has links)
This diploma thesis is focused on the problems of education of the students with specific behavioral disorders at the primary school level. The diploma thesis has a theoretical and empirical character. The theoretical part was created on the basis of scientific literature and is focused on the problems of the specific behavioral disorders ADD/ADHD. The practical part summarizes results of the research investigation which was done by observations and interviews. The investigation was aimed at methods used by the teachers while teaching the kids with specific behavioral disorders, at the cooperation of the teachers with the parents and experts and also at the ways of getting information related to problems of the specific behavioral disorders.
77

Enhancement of target detection using software defined radar (SDR)

Youssef, Ahmed 11 December 2018 (has links)
Three novel approaches that are based on a recent communication technique called time compression overlap-add (TC-OLA), are introduced into pulse compression (PC) radar systems to improve the radar waveform shaping and enhance radar performance. The first approach lays down a powerful framework for combining the TC-OLA technique into traditional PC radar system. The new TC-OLA-based radar obtained is compared with other radars, namely traditional linear frequency modulation (LFM), and wideband LFM which has the same processing gain under different background situations. The results show the superiority of the proposed radar over the others. The second approach combines a random phase noise signal with a selected radar signal to build a new radar system, SSLFM radar, that enjoys the low-probability of intercept property, and, therefore, has higher immunity against noise jamming techniques compared with other radar systems. The properly recovery of the transmitted signal, however, requires a synchronization system at the receiver side. In this dissertation, we propose three synchronization systems each having different pros and cons. The last approach takes the radar waveform design methodology in a different direction and proposes a novel framework to combine any number of radar signal and transmit them simultaneously. Instead of trying to achieve universality through waveform shaping optimization, we do so via pluralism. As a proof of concept, all the proposed radars have been implemented and tested on software-defined radar (SDR). The theoretical and the experimental results showed the superiority of all proposed radar systems. Since TC-OLA is fundamental to this work, we add a chapter to propose a new technique called downsample upsample shift add (DUSA) to address the limitations of the existing implementation of TC-OLA. / Graduate
78

Risk and Protective Factors Associated with the Adult Achievement of Substance-Using Adolescents: Findings from the National Longitudinal Study of Adolescent to Adult Health

Farrell, Dana G. 09 November 2016 (has links)
The literature has well-documented the deleterious effect of alcohol and other drug (AOD) use on adolescent development and future outcomes. Despite these devastating results, some adolescents are able to attain high achievement as adults, despite their earlier AOD use. Secondary quantitative analyses were conducted on nationally-representative data from the National Longitudinal Study of Adolescent to Adult Health. Longitudinal data, collected at Wave I (1994-1995), and Wave IV (2007-2008), were analyzed from a sample of 4,266 American high school students between the ages of 13-19 years. The majority of high school students in the sample self-reported AOD use (n=2,833, 66.4%), compared to those students who self-reported non-AOD-use (n=1,433, 33.6%). Statistically significant findings indicated that with the exception of household income, non-AOD-using adolescents experienced more favorable outcomes with regard to educational attainment, occupational status, and involvement with the criminal justice system when compared to their AOD-using counterparts. In addition, through ordinal and binomial logistic regressions, the present study identified risk and protective factors affecting the adult outcomes of adolescents who used AODs. Gender, age, grade level, importance of religion, frequency of prayer, fighting, suspensions, expulsions, and happiness in neighborhood were statistically significant in predicting educational attainment. Grade level and feeling safe in school were found to be statistically significant in predicting occupational status. Gender, fighting, suspensions, and alcohol use by best friends were statistically significant in predicting involvement with the criminal justice system.
79

Add-in v MS Excel pro tvorbu modelu systémové dynamiky / Add-in in MS Excel for creating models of system dynamics

Vlach, Michal January 2014 (has links)
This work deals with system dynamics. Its main task is to create and description of the add-in to Excel that allows users to model the stock and flow model directly in Excel. Furthermore, there is discussed about the general theory of system dynamics, systems and models. There is also described the history of programming languages and their development to C #, in which the supplement was created. The thesis also presents competition created add-in.
80

Evaluation of Two-Dimensional Codes for Digital Information Security in Physical Documents

Chen, Shuai 17 July 2015 (has links)
Nowadays, paper documents are still frequently used and exchanged in our daily life. To safely manage confidential paper information such as medical and financial records has increasingly become a challenge. If a patient's medical diagnosis get stolen or dumped without shredding, his or her private information would be leaked. Some companies and organizations do not pay enough attention to the problem, letting their customers suffer the loss. In the thesis, I designed a hybrid system to solve this problem effectively and economically. This hybrid system integrates physical document properties with digital security technology, which brings in a revolutionary idea for processing sensitive paper information in modern world. Based on that, I focus on different QR code sizes and versions, compare their attributes and relations, and find the best QR code size and version according to data amount in a given area. Finally I implement them in CryptoPaper word plugin, using several test cases to test the functionality of it.

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