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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.
521

Modern Error Control Codes and Applications to Distributed Source Coding

Sartipi, Mina 15 August 2006 (has links)
This dissertation first studies two-dimensional wavelet codes (TDWCs). TDWCs are introduced as a solution to the problem of designing a 2-D code that has low decoding- complexity and has the maximum erasure-correcting property for rectangular burst erasures. The half-rate TDWCs of dimensions N<sub>1</sub> X N<sub>2</sub> satisfy the Reiger bound with equality for burst erasures of dimensions N<sub>1</sub> X N<sub>2</sub>/2 and N<sub>1</sub>/2 X N<sub>2</sub>, where GCD(N<sub>1</sub>,N<sub>2</sub>) = 2. Examples of TDWC are provided that recover any rectangular burst erasure of area N<sub>1</sub>N<sub>2</sub>/2. These lattice-cyclic codes can recover burst erasures with a simple and efficient ML decoding. This work then studies the problem of distributed source coding for two and three correlated signals using channel codes. We propose to model the distributed source coding problem with a set of parallel channel that simplifies the distributed source coding to de- signing non-uniform channel codes. This design criterion improves the performance of the source coding considerably. LDPC codes are used for lossless and lossy distributed source coding, when the correlation parameter is known or unknown at the time of code design. We show that distributed source coding at the corner point using LDPC codes is simplified to non-uniform LDPC code and semi-random punctured LDPC codes for a system of two and three correlated sources, respectively. We also investigate distributed source coding at any arbitrary rate on the Slepian-Wolf rate region. This problem is simplified to designing a rate-compatible LDPC code that has unequal error protection property. This dissertation finally studies the distributed source coding problem for applications whose wireless channel is an erasure channel with unknown erasure probability. For these application, rateless codes are better candidates than LDPC codes. Non-uniform rateless codes and improved decoding algorithm are proposed for this purpose. We introduce a reliable, rate-optimal, and energy-efficient multicast algorithm that uses distributed source coding and rateless coding. The proposed multicast algorithm performs very close to network coding, while it has lower complexity and higher adaptability.
522

Limit theorems for a one-dimensional system with random switchings

Hurth, Tobias 15 November 2010 (has links)
We consider a simple one-dimensional random dynamical system with two driving vector fields and random switchings between them. We show that this system satisfies a one force - one solution principle and compute its unique invariant density explicitly. We study the limiting behavior of the invariant density as the switching rate approaches zero and infinity and derive analogues of classical probabilistic results such as the central limit theorem and large deviations principle.
523

Limit theorems for statistical functionals with applications to dimension estimation / Grenzwertsätze für statistische Funktionale mit Anwendungen auf Dimensionsschätzungen

Min, Aleksey 23 June 2004 (has links)
No description available.
524

A Spatially-filtered Finite-difference Time-domain Method with Controllable Stability Beyond the Courant Limit

Chang, Chun 19 July 2012 (has links)
This thesis introduces spatial filtering, which is a technique to extend the time step size beyond the conventional stability limit for the Finite-Difference Time-Domain (FDTD) method, at the expense of transforming field nodes between the spatial domain and the discrete spatial-frequency domain and removing undesired spatial-frequency components at every FDTD update cycle. The spatially-filtered FDTD method is demonstrated to be almost as accurate as and more efficient than the conventional FDTD method via theories and numerical examples. Then, this thesis combines spatial filtering and an existing subgridding scheme to form the spatially-filtered subgridding scheme. The spatially-filtered subgridding scheme is more efficient than existing subgridding schemes because the former allows the time step size used in the dense mesh to be larger than the dense mesh CFL limit. However, trade-offs between accuracy and efficiency are required in complicated structures.
525

A Spatially-filtered Finite-difference Time-domain Method with Controllable Stability Beyond the Courant Limit

Chang, Chun 19 July 2012 (has links)
This thesis introduces spatial filtering, which is a technique to extend the time step size beyond the conventional stability limit for the Finite-Difference Time-Domain (FDTD) method, at the expense of transforming field nodes between the spatial domain and the discrete spatial-frequency domain and removing undesired spatial-frequency components at every FDTD update cycle. The spatially-filtered FDTD method is demonstrated to be almost as accurate as and more efficient than the conventional FDTD method via theories and numerical examples. Then, this thesis combines spatial filtering and an existing subgridding scheme to form the spatially-filtered subgridding scheme. The spatially-filtered subgridding scheme is more efficient than existing subgridding schemes because the former allows the time step size used in the dense mesh to be larger than the dense mesh CFL limit. However, trade-offs between accuracy and efficiency are required in complicated structures.
526

Objekty živočišné výroby z hlediska hlukové zátěže okolního prostředí / Objects of livestock production in terms of ambient noise levels

LENC, Jan January 2011 (has links)
This thesis deals with the evaluation of noise exposure in the agricultural cooperative Hosín ? Dobrejovice. The aim of this work was to measure noise levels in the dairy barn area and its surroundings, during these processes work: milking, feeding, removal of excrement, bedding etc. Measurements were carried out in summer and autumn. During the measurement noise was the largest source of agricultural equipment. The results revealed that noise pollution resulting from the operation of agricultural cooperatives Dobrejovice is fair and negative influence on noise pollution does not occur.
527

Finite element limit analysis of offshore foundations on clay

Dunne, Helen P. January 2017 (has links)
Capacity analysis is a common preliminary step in the design of offshore foundations. Inaccuracies in traditional capacity analysis methods, and the advancement of numerical modelling capabilities, have increasingly led designers to optimise foundations using more complex methods. In this thesis, the ultimate limit state capacity of a range of foundation types is investigated using finite element limit analysis. Novel three-dimensional finite element limit analysis software is benchmarked against analytical solutions and conventional displacement finite element analysis. It is then used to find lower and upper bounds of foundation capacity, with adaptive mesh refinement used to reduce the bound gap over successive iterations of the solution. Rigid foundations subjected to short term loading on clay soil are analysed. The undrained soil is modelled as a rigid--plastic von Mises material, and attention is given to modelling any normal and/or shear stress limits at the foundation/soil interface. Shallow foundations, suction anchor foundations, and hybrid mudmat/pile foundations are considered. Realistic six degree-of-freedom load combinations are applied and results are reported in the form of normalised design charts, and tables, that are suitable for use in preliminary design. Relationships between loading combinations and failure mechanisms are also explored. A number of case studies based on authentic foundation designs are analysed. The results suggest that finite element limit analysis could provide an attractive alternative to displacement finite element analysis for preliminary foundation design calculations.
528

Measurable functions and Lebesgue integration

Brooks, Hannalie Helena 11 1900 (has links)
In this thesis we shall examine the role of measurerability in the theory of Lebesgue Integration. This shall be done in the context of the real line where we define the notion of an integral of a bounded real-valued function over a set of bounded outer measure without a prior assumption of measurability concerning the function and the domain of integration. / Mathematical Sciences / M. Sc. (Mathematics)
529

Proces realizace reformy zdravotní politiky v České republice. / Implementation of Health Policy Reform in the Czech Republic.

RICHTEROVÁ, Andrea January 2009 (has links)
The introduction of user fees and surcharges for medicinal products and foods for special medical purposes is considered to be one of the steps preceding the implementation of health policy reform. As of 1 January 2008, four basic fees were introduced in the Czech healthcare system with the objective of reducing unnecessary demand and misuse of health care. The objective of my Diploma Thesis was to map and evaluate the effects of the introduction of user fees on patients{\crq} number of visits to outpatient specialists. Three main objectives were formulated during my work on this thesis. The first objective was to provide a coherent overview of the issues related to the introduction and use of fees introduced on 1 January 2008 for outpatient specialists. The second objective was to compare patients{\crq} rate of visits to outpatient specialists with the year 2007. The third objective was to evaluate whether the patients{\crq} number of visits to outpatient specialists decreased in relation to age, gender, care provided, and kind of disease. Subsequently, four hypotheses were formulated. Hypothesis 1: The patients{\crq}rate of visits to outpatient specialists decreased compared to the year 2007 as a result of the introduction of user fees. Hypothesis 2: Compared to the year 2007, the introduction of user fees resulted in no considerable decrease in the rate of visits for patients with chronic diseases. Hypothesis 3: The impact of user fees on the rate of visits to outpatient specialists will be comparable for both genders. Hypothesis 4: The introduction of user fees will not result in a prolongation of the interval between the respective visits of patients to outpatient specialists. Quantitative research and method of questioning were used to achieve the goals and verify the hypotheses. The questionnaire technique was used for data collection. The research survey group for the questionnaire comprised physicians with outpatient specialties practicing in South Bohemia, Hradec Králové, Liberec,and Plzeň Regions, Capital City of Prague, Central Bohemia, Ústí and Zlín regions. The final research group comprised 79 specialist physicians with specialties as follows: allergology and clinical immunology, anesthesiology, dermatovenerology, gynecology, surgery, internal medicine, pneumology, ophthalmology, ENT, oncology, orthopedics, neurology, psychiatry, rehabilitation, and urology. The Diploma Thesis met its main objectives, as well as its partial objectives. The second, third, and fourth hypotheses were confirmed. The first hypothesis was not verified successfully in this research. The results of my research suggest that user fees had an impact on patients{\crq} rate of visits to outpatient specialists and can be used for publication in professional journals.
530

Porozumění a postoje laické veřejnosti k současné reformě zdravotnictví / Understanding and Public Approach to Contemporary Health Reform

BORŮVKOVÁ, Eliška January 2009 (has links)
Abstract Understanding and attitudes of the public towards the current Health Care Reform This thesis summarizes the basic facts about the current reform within the Health Care Sector and how it is being perceived by the general public. The theoretical part focuses on the basic information about the development of the Health Care Sector in the Czech Republic and its current reform. The development of the Health Care Sector from the year of 1918 until present is highlighted. At the beginning of the last decade of the 20th century, a new set of laws were passed, which triggered the initial reform of the Czech Health Care Sector. However, a period of passivity regarding subsequent legislation has resulted in the present problems. Further, there is a focus on current Health Care Reform enquiring: why the reform is needed, the nature of its stages and its legislative and non-legislative changes. Only a small part of the reform measures came into force. This included the introduction of regulation fees, the introduction of an `annual safe limit{\crq}, and the pricing and payment for medication. The practical part presents the research findings in relation to the issues mentioned above. The research part of the thesis, carried out using questionnaires, is concerned with the views of the public with respect to current Health Care Reform and investigates whether it has been understood by the public. The research shows that most of the respondents disagree with the reform and think that it is not developing in the right direction. The majority of respondents with this view were found to be within the age group of 60 and over, and within the group of respondents with a basic level or vocational education. Further, the research suggests that the public is not adequately informed about the new Health Care Reform, and therefore demonstrates a lack of understanding of its nature. In addition, the current political climate suggests that the public may lose interest in these issues and will become disengaged with the reform without further consideration.

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