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127 Uppsatser om Variance Decomposition - Sida 3 av 9
Genom statistisk analys utvärdera geometriska parametrars påverkan på ett XPI- cylinderhuvuds snurrtal
This Master Thesis is a product development project that has been carried out in cooperation with Scania CV AB. The purpose has been to find the relationship between geometric parameters and the swirl number for an XPI- cylinder head in order to improve the design specification.The increased focus on environmental issues from society leads to tighter emission legislations for the truck manufactures. In order to drive the development forward considerable resources are spent on research and development on diesel engines and its combustion process. The inlet air has a significant impact on the formation of emissions and the flow that is desired is called swirl. Swirl is achieved by making the air rotate around the vertical axis of the cylinder.Earlier cylinder heads that has been developed at Scania CV AB have shown clear relationships between geometric parameters of the cylinder head and the swirl number.
Från avfall till mylla : En litteraturstudie om komposteringsprocesser
Syftet med studien handlar om att försöka förstå vilken betydelse trädgårdsmiljön har för människor som bor i bostadsrättslägenheter - ur ett hälsomässigt, estetiskt och skötselmässigt perspektiv. Framför allt handlar studien om att ta reda på hur medlemmarna använder sin trädgård och om den har någon hälsomässig betydelse. Studien ska undersöka hur de ser på utformningen av trädgårdsmiljön i sitt bostadsområde, samt hur de skulle föredra att ha den. Den ska också undersöka vilken syn medlemmarna har på skötselfrågan och hur föreningen valt att lösa skötseln av trädgården. Studien bygger på fem kvalitativa intervjuer med representanter från bostadsrättsföreningar som fått besvara frågor om medlemmarnas syn på sina trädgårdsmiljöer..
Kommunfullmäktigeledamöters sociala representation -en fallstudie i tre svenska kommuner av kön, ålder och etnicitet
The purpose of the thesis has been to explore the use of hedge fund styles when constructing portfolios of hedge funds (i.e. funds of hedge funds). The central question is if the use of hedge fund styles can significantly explain and improve risk adjusted returns (characterized by Sharpe ratios). The study has been done in collaboration with Optimized Portfolio Management AB who desire further knowledge and evaluation of hedge fund styles for their fund of hedge funds.To be able to create successful ex ante portfolios we have explored various prediction models for both risk and return. Our findings indicate that return prediction is problematic using simple models such as regression since the risk exposure of the indices appear to change significantly over time.
Tryckalgometri hos friska hästar :
There are no reliable, objective and simple methods today for measuring pain in horses. The purpose of this study was to evaluate and describe measuring of mechanical nociceptive threshold (MNT) values with a pressure algometer in clinically pain free riding horses at the riding school of Strömsholm. In this study there were 24 horses. Tape recording and electromyelografi (EMG) was used in an attempt to increase objectivity in the examination. MNT increased with age, however sex and colour had no influence.
Strötorvsanvändning i djurstallar : en litteraturgenomgång
Peat litter has been used in animal houses for a long time. Because of its good ability to absorb liquid and nutrients from the manure it can create a dry surface for animals and a valuable manure product. Through changes in agricultural practises the use of peat litter has diminished and is to a great extent replaced by straw, sawdust and cutter shavings although Sweden is rich in peat-findings.
The aim of this work was to summarize the presented knowledge about the used of peat
litter, techniques, advantages and disadvantages and to compare with other commonly
used litter materials. Articles on peat litter have been searched for in magazines, databases and books at SLU library. Visits to peat industries, interviews with peat producers and with peat researchers contributed to the material.
Peat is not a uniformly material.
????Att lösa reglertekniska problem med Modelica
Modelica is a multi-domain and equation-based modeling language. Modelica is based on object-oriented principles and non-causal modeling. The language is constructed to facilitate reuse and decompose models. The models and the modellibrary can modified to design a new nonlinear components.Object-oriented modeling is an excellent way to analyze and study large complex heterogeneous physical systems. The object-oriented modeling approach build on reusing and decomposition of models and non-causal modeling.Modeling physical systems often leads to a DAE system with index 2 or 3.
Automatisk tesauruskonstruktion med latent semantisk indexering
The aim of this thesis is to examine how thesauri constructed with latent semantic indexing LSI are performing when used for query expansion. There is a well-known problem with synonymy in information retrieval and one solution to this problem is to use a thesaurus. In this thesis thesauri are created automatically to find statistically related words and not only synonyms. LSI is a method that uses singular value decomposition SVD to reduce dimensions in a matrix and find latent relationships between words. We constructed nine thesauri and used them for query expansion in a Swedish database, GP_HDINF.
Introduktion av Open Source som arbetssätt
In early January 2010 the authors participated in a meeting with the chief engineer for a company in which a central part is manufacturing of printed circuit boards (PCB). At this meeting it emerged that the machinery and production methods have changed substantially since the early 1990's. The spreadsheet for preliminary production time calculations by the company is today based on conditions from almost 20 years ago. The company has over the years been trying to adjust the spreadsheet template. The result of these adjustments has filled it with historical residue, something which makes the template difficult and time consuming when the primary user tries to handle it.The purpose of this study was to help the company increase its accuracy in the representation of the production times for the different PCB-based products by developing a new costing model based on an already existing but inadequate spreadsheet template. The company also expressed the wish that the new costing model would be less time consuming to work with.The methods used to achieve the goal are interviewing, participatory observations and meetings with relevant persons. The data obtained were analyzed using the theory on PCB production and visualization of data.
Populationsstruktur och genetisk analys av exteriöra egenskaper hos svensk ardenner :
The purposes of this study were to estimate genetic and phenotypic parameters for conformation traits in Swedish Ardenner, a heavy draught horse, and to investigate the inbreeding status of the population. Additionally, a breeding scheme proposal was created, based on the results achieved in the study.
The data studied were obtained from the Swedish Horse Board and from the Swedish Ardenner Association. The data included 1632 three-year-old horses, mainly mares, and 356 stallions, judged between 1986 and 2005 at conformation shows. The traits studied were type, head-neck-body, legs, walk and trot at hand, total score and height at withers.
Frosttolerans hos douglasgran av olika ursprung och tillväxttyp
This report evaluates whether normal approximation or resampling is to prefer for estimating the distribution of the sample mean and functions of the sample mean. The evaluation relies on simulation studies. The observations of the sample are allowed to be differently distributed. In the case of sample means they are also allowed to be dependent.For sample means the two approximations behaves very similar. The most important component whether we have a good or a bad approximation is how good the approximations catch the variance of the true distribution.
Statistisk analys av barnpsykiatrisk symptomatologi som ökar risken för senare personlighetsstörning
This report evaluates whether normal approximation or resampling is to prefer for estimating the distribution of the sample mean and functions of the sample mean. The evaluation relies on simulation studies. The observations of the sample are allowed to be differently distributed. In the case of sample means they are also allowed to be dependent.For sample means the two approximations behaves very similar. The most important component whether we have a good or a bad approximation is how good the approximations catch the variance of the true distribution.
Beräkningsmodul för ett förbättrat offertförfarande och minskad icke-värdeskapande tid
In early January 2010 the authors participated in a meeting with the chief engineer for a company in which a central part is manufacturing of printed circuit boards (PCB). At this meeting it emerged that the machinery and production methods have changed substantially since the early 1990's. The spreadsheet for preliminary production time calculations by the company is today based on conditions from almost 20 years ago. The company has over the years been trying to adjust the spreadsheet template. The result of these adjustments has filled it with historical residue, something which makes the template difficult and time consuming when the primary user tries to handle it.The purpose of this study was to help the company increase its accuracy in the representation of the production times for the different PCB-based products by developing a new costing model based on an already existing but inadequate spreadsheet template. The company also expressed the wish that the new costing model would be less time consuming to work with.The methods used to achieve the goal are interviewing, participatory observations and meetings with relevant persons. The data obtained were analyzed using the theory on PCB production and visualization of data.
En utvärdering av två olika sa?tt att skatta fördelningen till stickprovsmedelvärden från olikfördelade data - normalapproximation kontra resampling
This report evaluates whether normal approximation or resampling is to prefer for estimating the distribution of the sample mean and functions of the sample mean. The evaluation relies on simulation studies. The observations of the sample are allowed to be differently distributed. In the case of sample means they are also allowed to be dependent.For sample means the two approximations behaves very similar. The most important component whether we have a good or a bad approximation is how good the approximations catch the variance of the true distribution.
En slumpmässig vandring eller genomsnittlig återgång : Råder förutsägbarhet på Stockholmsbörsen?
This study has been conducted in order to determine the existence of predictability for the Stockholm stock exchange. With this purpose the random walk theory has been raised against the theory of mean reversion in order to determine which theory is the most substantial. Data has been collected from Nasdaq OMX Nordic and furtherly been processed using the statistical software EViews. Swedish listed companies? daily share values between 2000-2014 have been analyzed using two tests; an Augmented Dickey Fuller test and a Variance Ratio test.
Implementation av webbsida för rekommendationssystem med användaruppbyggd databas
The goal of this project was to create a web-based, crowd-sourced, correlational database, that easily allowed users to submit objects and receive correlated objects as results. The webservice was created in the web development languages of HTML, CSS, PHP and Javscript, with MySQL to handle the database. Simultaneous development was kept in check with the aid of the source code management system GIT. Upon completion, the service contained several HTML-views, the ability to add and rate objects, a per-object dedicated page with information parsed from Wikipedia.org, and a view with objects ranked in accordance to the preferences specific to the current user. Roughly a month after the beginning of development, the website was publicly launched and promoted in order to collect data, and improvements were added to the website as needed.