Sökresultat:
370 Uppsatser om Numerical simulations - Sida 21 av 25
Implementering av höghastighetsgränssnitt i 0,15 µm halvledarprocess
This study investigated the possibility of implementing three standards, Transistion Minimized Differential Signaling (TMDS) and two versions of Stub Series Terminated Logic (SSTL), for inter-chip communication in a specific manufacturing process. The two SSTL standards were implemented in one transceiver system while TMDS was implemented in a separate system. The evaluation was done with Spice simulations on schematic level with some parasitic capacitance and resistance. The idea was to investigate the possibility of implementing these standards and get an idea of eventual shortcomings. In order to create models as a basis for evaluation, simulation environments with models for circuit board and packages were created and transmitters and receivers were designed.
Simulation of rattan harvests in Indonesia : different harvesting pressures and the resulting patterns
The objectives of this research were to determine whether the natural rattan resources in Sulawesi, Indonesia can cope with the strongly increased harvesting pressure that has occurred over the last centuries. I was furthermore looking for patterns in the rattan population dynamics that might give a hint on how the harvesting system could be improved to ensure a maximum sustainable yield. To
answer these questions, I developed an individual-based model to analyse the dynamics of rattan growth in connection with rattan harvests by locals to identify sustainable levels of rattan harvests around villages in Sulawesi, Indonesia. Scenarios with different harvesting intensities were run to compare the change in harvest amount. For a given harvesting pressure, scenarios with a high number of harvesters and a low harvesting frequency had the same effect as scenarios with high harvesting frequencies and a low number of harvesters.
Förändring i färdigvarulager och utlastningen av foder efter införande av en ny produktmix : En fallstudie på Lantmännen Agroetanol
This Master thesis was written for Lantmännen Agroetanol in Norrköping concerning the layout of their finished goods inventory and unloading of feed after introducing a new product mix. Lantmännen Agroetanol has two production lines which produces feed. Both lines lead to six silos, used as inventory of finished goods. The feed from the two production lines differ in terms of quality, where as Lantmännen Agroetanol wants to separate their finished inventory in order to charge a higher price, by selling the better product as a premium. With two different feed products the yearly revenue is expected to increase which motivates a research about the current capabilities and necessary changes to be made in the factory.
Simulering av simulinkmodeller medExtended Kalman FilterTidsoptimering av integrering
Simulation of different systems can be done using a graphical model description of the system based on block diagrams. The simulation software Matlab/Simulink offers a lot of possibilities to describe a huge number of systems, which can be linear as well as nonlinear. The simulation using Matlab/Simulink is done by integration based on different kinds of numerical methods.When nonlinear Simulink-models are simulated, it is often interesting to apply a Kalman filter to handle the noise that may occur within the process as well as corrupting the measurement. However, application of such a filter leads to an extensive time-consumption despite using fast computers. The reason is that the existing Matlab functions are not constructed for time optimal evaluation.
Transporttidsmodellering vid provpumpning i heterogen jord : spårämnesförsök i en isälvsavlagring
When protection zones for wells are delineated, it is important to acquire good knowledge about possible travel time from different points in the catchment area to the well. Often, simple analytical methods are used for estimating travel times and the assumption is made that the hydraulic conductivity is relatively homogenous within the aquifer. Nevertheless, many aquifers are strongly heterogeneous which may lead to differences between estimates and actual travel times. As a part of the process to develop improved methods for delineating protection zones for groundwater supply wells, a tracer experiment was performed in a glaciofluvial esker formation in Järlåsa. On the basis of the experiment, a numerical flow model was created for the test site.The purpose of this master?s thesis was to apply the flow model to an aquifer where the hydraulic conductivity shows great variability and should be described by a stochastic distribution.
I havet av siffror och bokstäver : En studie om matematik- och lässvårigheter hos barn i andra klass
It is not uncommon for math difficulties and reading difficulties to occur simultaneously. Despite this, math and reading difficulties are thought to have different cognitive profiles where math difficulties are linked to number sense; an innate ability to understand, approximate and manipulate both quantities and numerical information, whereas reading difficulties are linked to phonological ability; an innate ability to understand, create representations of and manipulate phonological information. A possible link between the difficulties is that phonological abilities also could affect mathematical ability. Support for this comes from studies where comorbid math and reading difficulties are associated with more severe difficulties in arithmetic ability compared to those with isolated math difficulties. The purpose of this study is to examine whether isolated math difficulties, isolated reading difficulties and comorbid math and reading difficulties can be linked to deficits in number sense, phonological ability or both of these, and whether comorbid math and reading difficulties differ in performance in mathematical tasks compared to isolated math difficulties for children in second grade.
Ger tillägg av ARB till redan pågående behandling med ACE-hämmare hos hjärtsviktspatienter bättre hälso- och kostnadseffekt?
Heart failure is a condition where the heart is incapable of providing adequate blood supply to different organs in the body. The underlying causes of heart failure is some kind of disorder in the heart function, and require careful diagnostics. The basic symptoms that arise from heart failure is difficulty in breathing, that aggravate when lying down, and fatigue. The patients? symptoms and impaired quality of life can be in different stages depending on the severity of the heart failure.
Formgivning av ögonduschkork : Examensarbete, formgivning
This Master thesis was written for Lantmännen Agroetanol in Norrköping concerning the layout of their finished goods inventory and unloading of feed after introducing a new product mix. Lantmännen Agroetanol has two production lines which produces feed. Both lines lead to six silos, used as inventory of finished goods. The feed from the two production lines differ in terms of quality, where as Lantmännen Agroetanol wants to separate their finished inventory in order to charge a higher price, by selling the better product as a premium. With two different feed products the yearly revenue is expected to increase which motivates a research about the current capabilities and necessary changes to be made in the factory.
Klibbalens gödslingseffekt på volymproduktionen i ett blandbestånd av gran och klibbal : en simulering i Heureka
A secondary and a pioneer tree species can with advantage be included in a mixed stand to increase the use of sunlight. Nitrogen-fixing plants have been shown to increase the supply of nitrogen in the soil by, for example, litter fall. This deposition acts as a biological fertilization, which may be used by non-fixing plants. Alder is a nitrogen-fixing, pioneer tree species that loses its nitrogen-rich leaves late in the autumn. The aim of this study was to examine the effect on the total volume of production, when different proportions of nitrogen-fixing Alder were part of spruce stands.
Robotiserad produktionsanpassad magnetmontering för vågkraftverk
This thesis work includes studies and simulation how magnetization of the translator in a linear generator for wave power can be automated. The translator is the moving component in the generator that is "dressed" with permanent magnets. The translator is magnetized with rectangle-shaped permanent magnets that are today's strongest permanent magnet type of neodymium-iron-boron (NdFeB).Eight equivalent metal sheets are mounted around the translator. The plates have milled tracks where 106 permanent magnets per sheet are mounted. Today the assembling of the magnets is done by hand, which is a very tedious and time-consuming work. This project presents investigations about the automation of the translator magnetization theoretically and simulation results are preformed in ABB's robot simulation software RobotStudio. Even robot-held tool was designed that enables the robot to be able to magnetize the translator in a simple manner. The investment cost is roughly 1.5 million SEK. With an economic life-time of five years, the investment costs are estimated to 24000 SEK / month. According to the calculations, this project is very motivated to implement, as it provides savings up to 17 000 SEK per translator which is 10.2 million SEK assuming that the robot cell is operating at full speed the whole year.According to this thesis work the result is a 4x9 meter cell with two industrial robots of the type ABB IRB6650S.The cycle time to magnetize one translator was calculated to about 10 hours.This prototype of project can possibly be implemented in a full-scale production line and performed according to the calculations and simulations presented in the report. Further work is suggested to improve the tool.Lyssna .
Population and management models for the Swedish wild boar (Sus scrofa)
The wild boar Sus scrofa population in Sweden has increased rapidly in the last decades which has led to conflicts among stakeholders, for example due to crop damages in agriculture. Thus, there is an urgent need of quantified goals and effective strategies for wild boar management. To develop such strategies, knowledge on population dynamics is fundamental. In this study a deterministic matrix model was used to estimate population growth, based on previously published data. The exponential growth rate for a wild boar population was calculated to 1.48.
ADS och Matlab för optimering av pre-distortion av effektförstärkare
This master?s thesis deals with integrating simulations using Agilents Electronic Design Automation tool ADS with customized Matlab scripts, for solving complex analog and digital radio architectures. In particular, it addresses predistortion, realized in the digital domain, of power amplifiers, modeled in the analog domain. The former is implemented in Matlab while the latter is implemented in ADS. Two versions of integrating the two systems have been tested: 1) Iterative approach on sample basis and 2) Scheduled batch solution by matrix inversion.
Development of Liquid Cooling for PCs
In recent years, existing solutions for cooling personal computer CPUs have been supplemented by a new product category, factory sealed water cooling loops. These systems, consisting of a water block with an integrated pump, a fan and a radiator, perform well compared to the air cooling solutions but are less effective than larger, custom-built water cooling systems.This project aims to explore the most important aspects of a factory sealed system and to identify possible cost-effective enhancements of the performance.The most significant differences between the different groups of water cooling loops are the block design and the pumping power. The performance of both categories is also largely dependent on the fan power, but increasing fan power has a large negative impact on the noise level.Both radiator size and fan model choice appear, in tests, to be relatively unimportant, presuming that the noise level is kept constant. The position and direction of the fan, however, has significant impact on both the temperature and the sound level.Water blocks can be designed in several different ways, both regarding the heatsink design and the flow direction. In simulation, flow with the inlet centered above the heatsink result in considerably lower pressure drop and slightly higher temperatures than flow through the block, for heatsinks with fin arrays.Creating a competitive product in this product segment certainly seems possible, as there are performance-increasing changes to be made that seemingly has little impact on the production cost.
Planering, förutsättningar ocheffekter av implementering avsolceller i stadsutvecklingsprojekt.
Today, buildings utilize 40 % of the total energy consumption. New energyrestrictions and directives have entered the construction industry. Photovoltaic is asustainable, clean and quiet solution that integrates well in the urban environment buthave not yet reached a breakthrough on the Swedish market. The conditions for solarenergy production are often set in the early planning stages where they rarely arebeing prioritized.This master of engineering project focuses on identifying problems regardingimplementation of photovoltaic in city development projects and giving suggestions topossible improvements in the planning- and construction process. It also givesrecommendations on how the conditions for energy production can be optimized inthe early zoning stage.By conducting simulations with PVsystV5.21, on three ongoing city developmentprojects in Umeå, Malmö and Stockholm and by carry out and analyzing interviewswith city planners, constructors and architects, some conclusions have been made.Several improvements, both politically, with changes in the subsidization systemand/or instatement of a new law with feed-in tariffs, and within the solar- andconstruction industry itself, with better communication between different parts of theprocess as well as better use of experience, can be made.
Klimatsimulering av ett kontorsrum : Hur de termiska stigkrafterna påverkar ventilationseffektiviteten
AbstractIn urban societies people spend more and more time indoors, which put great demands on the indoor environment. If the ventilation is to manage the removal of unwanted substances in the indoor air, a good mixing of the air is required. The question arises that, whether the buoyancy forces will counteract a good mixing of the indoor air or not?This report aims to clear up the difficulties whether you need to consider the buoyancy forces or not, when adjusting a ventilation unit. For studying the indoor mixing of the air a two dimensional model is constructed in COMSOL Multiphysics.