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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.
231

Micromachining Metrology: Measurement and Analysis of Dynamic Tool-tip Trajectory when using Ultra-High-Speed Spindles

Nahata, Sudhanshu 01 May 2018 (has links)
There is a growing demand for miniature, high-precision components and devices with micro-scale features for applications in biomedical systems, aerospace structures, and energy storage/conversion systems. Mechanical micromachining has become a leading approach to address this demand. In micromachining, a micro-scale cutting tool, such as a micro-endmill with a diameter as small as 10 um, is rotated by an ultra-high-speed (UHS) spindle (speeds greater than 60,000 rpm, reaching up to 500,000 rpm) to mechanically remove the material from a workpiece. Although micromachining resembles the traditional computer numerically controlled (CNC) machining processes, the micron-scale cutting tools, ultra-high-speed (UHS) spindles, and considerably tighter tolerance requirements bring unique challenges to micromachining.
232

Adaptace programů ve Scale zaměřená na výkon / Performance based adaptation of Scala programs

Kubát, Petr January 2017 (has links)
Dynamic adaptivity of a computer system is its ability to modify the behavior according to the environment in which it is executed. It allows the system to achieve better performance, but usually requires specialized architecture and brings more complexity. The thesis presents an analysis and design of a framework that allows simple and fluent performance-based adaptive development at the level of functions and methods. It closely examines the API requirements and possibilities of integrating such a framework into the Scala programming language using its advanced syntactical constructs. On theoretical level, it deals with the problem of selecting the most appropriate function to execute with given input based on measurements of previous executions. In the provided framework implementation, the main stress is laid on modularity and extensibility, as many possible future extensions are outlined. The solution is evaluated on a variety of development scenarios, ranging from input adaptation of algorithms to environment adaptations of complex distributed computations in Apache Spark.
233

What is driving house prices in Stockholm?

Ångman, Josefin January 2016 (has links)
An increased mortgage cap was introduced in 2010, and as of May 1st 2016 an amortization requirement was introduced in an attempt to slow down house price development in Sweden. Fluctuations in the house prices can significantly influence macroeconomic stability, and with house prices in Stockholm rising even more rapidly than Sweden as a whole makes the understanding of Stockholm’s dynamics very important, especially for policy implications. Stockholm house prices between the first quarter of 1996 and the fourth quarter of 2015 is therefore investigated using a Vector Error Correction framework. This approach allows a separation between the long run equilibrium price and short run dynamics. Decreases in the real mortgage rate and increased real financial wealth seem to be most important in explaining rising house prices. Increased real construction costs and increased real disposable income also seem to have an effect. The estimated models suggest that around 40-50 percent, on average, of a short-term deviation from the long-run equilibrium price is closed within a year. As of the last quarter 2015, real house prices are significantly higher compared to the long run equilibrium price modeled. The deviation is found to be around 6-7 percent.
234

The benefits of applying the results based management life-cycle approach to the crushing and screening process of Run of Mine

Madiba, Khaya 26 June 2015 (has links)
M.Phil. (Engineering Management) / Please refer to full text to view abstract
235

Cellular automata pseudorandom sequence generation

Acharya, Smarak 25 August 2017 (has links)
Pseudorandom sequences have many applications in fields such as wireless communication, cryptography and built-in self test of integrated circuits. Maximal length sequences (m-sequences) are commonly employed pseudorandom sequences because they have ideal randomness properties like balance, run and autocorrelation. However, the linear complexity of m-sequences is poor. This thesis considers the use of one-dimensional Cellular Automata (CA) to generate pseudorandom sequences that have high linear complexity and good randomness. The properties of these sequences are compared with those of the corresponding m-sequences to determine their suitability. / Graduate
236

Robust nonlinear model predictive control of a closed run-of-mine ore milling circuit

Coetzee, Lodewicus Charl 27 September 2009 (has links)
This thesis presents a robust nonlinear model predictive controller (RNMPC), nominal nonlinear model predictive controller (NMPC) and single-loop proportional-integral-derivative (PID) controllers that are applied to a nonlinear model of a run-of-mine (ROM) ore milling circuit. The model consists of nonlinear modules for the individual process units of the milling circuit (such as the mill, sump and cyclone), which allow arbitrary milling circuit configurations to be modelled easily. This study aims to cast a complex problem of a ROM ore milling circuit into an RNMPC framework without losing the flexibility of the modularised nonlinear model and implement the RNMPC using open-source software modules. The three controllers are compared in a simulations study to determine the performance of the controllers subject to severe disturbances and model parameter variations. The disturbances include changes to the feed ore hardness, changes in the feed ore size distributions and spillage water being added to the sump. The simulations show that the RNMPC and NMPC perform better than the PID controllers with regard to the economic objectives, assuming full-state feedback is available, especially when actuator constraints become active. The execution time of the RNMPC, however, is much too long for real-time implementation and would require further research to improve the efficiency of the implementation. / Thesis (PhD)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted
237

Implications of voluntary reductions in energy-related emissions for the environment and economic welfare in Malawi : an environmental general equilibrium approach

Banda, Benjamin Mattondo 23 October 2010 (has links)
This study estimates an energy sector model consisting of interfuel substitution model and an aggregate energy and non-energy input demand system that incorporates short-run and longrun structural adjustment parameters. The study finds that all fuels in the energy aggregate are Morishima substitutes and that there are significant sectoral variations in magnitude of the elasticities. This indicates that economic instruments should be considered for energy policy but such policies should take into account not only differences in technology used across sectors but also the systematic distribution of costs when the relative prices of fuels change. Estimates of long-run elasticities for aggregate input demands indicate that energy-capital input ratios adjust faster than labour-capital input ratios. This suggests that investment policy should take into consideration tradeoffs between environmental gains and employment implicit in the production structure of the Malawian economy as both capital and labour demands have dynamic interactions with energy in the long-run with potential significant cumulative impacts on the environment. Using results and gaps noted from the partial equilibrium analysis, the study also evaluated general equilibrium impacts of reducing fossil and biomass fuel use by production activities while investing in more hydroelectricity. The results show that carbon emissions and forest resource depletion due to energy use, respectively, can be reduced by imposing environmental taxes aimed at inducing a shift from biomass and fossil fuels to hydroelectricity. More significantly, there are at least three dividends from inducing a shift in the energy mix in that the economy can attain GDP at least equal to the value before imposition of environmental taxes in addition to reducing carbon emissions and deforestation. Further, redistributing the environmental tax revenues to reduce direct taxes on households leads to better income distribution. These findings have direct policy relevance to the contemporary challenges to sustainable development under the added burdens of climate change. Most importantly is what developing countries can do to strategically position themselves in global agreements on financing for climate change adaptation and mitigation. The general equilibrium estimate of direct environmental cost associated with the use of fossil and biomass fuels is close to the moderate estimate of social cost of deforestation in the National Environmental Action Plan (NEAP). This is significant because in the absence of estimates of damages of secondary impacts of both carbon emissions and deforestation, the optimal energy tax as inferred from the general equilibrium model corresponds to the annual growth rate in the economy’s energy intensity. In addition, since short-run to medium term environmental impacts are critical when data on secondary damages are unavailable, it would be prudent to target growth in intensities of use of fuels that contribute to the economy’s footprint on the environment. The study also proposes alternatives to carbon emission taxation that could complement the current legislation on land use by agricultural estates. / Thesis (PhD)--University of Pretoria, 2010. / Agricultural Economics, Extension and Rural Development / unrestricted
238

Analýza marketingovej komunikácie značky Mattoni v spojení s Run Czech / Analysis of marketing communication Mattoni in conjunction with RunCzech

Kočan, Anton January 2014 (has links)
This thesis elaborates and suggests marketing communication activities of the project Mattoni FreeRun. The activities to be used in the project are also accompanied by suggestions and improvements, which may inspire the project management to communicate ideas. The main idea of the project is to activate Mattoni FreeRun runners together with the brand, which aims to combine running and water Mattoni in one indivisible community, which will be perceived among runners and will long continue in their minds. Project Mattoni FreeRun will try to point out through selected activities mutual and almost integral connection between running and water in daily active, but also ordinary people's lives. The main thrust of the project Mattoni FreeRun is for its existence with its partners (RunCzech, Addidas) and some people, the so-called "ambassadors" to create a running community that will spread the idea between themselves and the general public.
239

Optimalizace inbound logistiky u vybrané společnosti v automotivu / Optimization of inbound logistics in selected company from automotive industry

Kuljačková, Tereza January 2012 (has links)
The Master's Thesis is focused on optimization of inbound logistics of Toyota Peugeot Citroën Automobile. The aim of the Master's Thesis is analysis of current status of logistics in TPCA and detailed observation and research of logistic processes and routes with emphasis on the planning system. Factors affecting the decision making during logistics planning and process of information searching were identified with special attention for milk-routes. First chapter describes development of logistics a specifics of logistics in automotive industry. Following chapter analyse current status of logistics, types of logistic routes a system of the planning. Third chapter propose options for logistics planning optimization with help of improved information source obtaining, study the suitability of used logistics routes and test possibilities of utilization of commercial software. Last chapter of thesis is comparing logistics of TPCA and Škoda Auto.
240

The effect of mergers and acquisitions on long-run financial performance of acquiring companies

Halfar, Dieter Bernhardt 01 July 2012 (has links)
Mergers and acquisitions continue to enjoy importance as strategies for achieving growth, although their success in creating shareholder value remains contested. The aim of this research was to evaluate whether, in the long-run, acquiring companies created or destroyed value by evaluating the differences between pre- and post-acquisition firm performance, using, abnormal share price performance, operating financial performance and intrinsic value performance metrics. This research used a non-representative, judgemental sample of 29 JSE listed firms to conclude that, on average, mergers and acquisitions destroy value within two years post-acquisition, although some evidence was found in support of acquiring firm value creation in the third year after the acquisition. Results indicated a significant -6.62% decline in acquiring firm average cumulative average abnormal return (ACAAR) between 504 trading days before and after acquisition announcement dates. This finding reversed in year three, resulting in a positive ACAAR of 8.76%. Similarly, average intrinsic value (AIV) performance indicated that between one year before and one year after the acquisition, AIV deteriorated with a significant -0.131. However, between year one and two after the acquisition, AIV recovered by 0.112. Overall evidence indicated positive and significant AIV growth of 0.370 between one year before and three years after the acquisition. The research found insignificant results for the pre and post-acquisition evaluation of industry-adjusted cash-flow return on all assets (IACRAA). / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

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