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735 Uppsatser om Piecewise linear regression - Sida 3 av 49

Identifiering av röjningsbestånd med hjälp av flygburen laserskanning

Bergvik Skog is one of the leading forest companies in Sweden who use airborne laser scanning for forestry information. They utilize laser data retrieved by the Swedish National Land Survey to describe the forest holdings and facilitate planning for thinning and final felling operations. However, the possibility to identify stands with clearing needs by using laser scanning data has not been tested in a large scale. The data used in the current study are field data from The Swedish National Forest Inventory in combination with laser data from the Swedish National Land Survey acquired in 2009. The collected data is used to find one or several laser variables that best describe the relationship of the field measured samples with clearing needs.

Elförbrukningen i svenska hushåll : En analys inom projektet ?Förbättrad energistatistik i bebyggelsen? för Energimyndigheten

Energimyndigheten har drivit ett projekt kallat ?Förbättrad energistatistik i bebyggelsen? för att få mer kunskap om energianvändningen i byggnader.  Denna rapport fokuserar på ?Mätning av hushållsel på apparatnivå? som var ett delprojekt.Diverse regressionsmodeller används i denna rapport för att undersöka sambandet mellan elanvändningen och de olika förklarande variablerna, som exempelvis hushållens bakgrundsvariabler, hushållstyp och geografiska läge, elförbrukningen av olika elapparater samt antalet elapparater.Datamaterialet innefattar 389 hushåll där de flesta är spridda runt om i Mälardalen. Ett fåtal mätningar gjordes på hushåll i Kiruna och Malmö.Slutsatsen vi kan dra från denna uppsats är att hushållens bakgrund, hustyp, geografiska läge och antal elapparater samt dessa apparaters typ har relevans för elförbrukningen i ett hushåll..

DEHP - från mjukgörare till hormonstörande

Eutrophication is a major problem in the Baltic Sea, as a result of increased loading of nitrogen and phosphorus. In the coastal parts of Östergötland the soil largely consists of clay and contains high levels of phosphorus bound to clay particles. Erosion of the soil in agricultural areas makes the water turbid and transports phosphorus to the Baltic Sea. The aim of this project was to examine the relationship between phosphorus and turbidity in the coastal streams of Östergötland. The aim was also to evaluate the possibility to use turbidity as a surrogate measure for phosphorus.

Turbiditet som ersättningsmått för totalfosforhalt i kustmynnande vattendrag i Östergötland

Eutrophication is a major problem in the Baltic Sea, as a result of increased loading of nitrogen and phosphorus. In the coastal parts of Östergötland the soil largely consists of clay and contains high levels of phosphorus bound to clay particles. Erosion of the soil in agricultural areas makes the water turbid and transports phosphorus to the Baltic Sea. The aim of this project was to examine the relationship between phosphorus and turbidity in the coastal streams of Östergötland. The aim was also to evaluate the possibility to use turbidity as a surrogate measure for phosphorus.

Konstruktion av current conveyors via makromodellering

A current conveyor is an active building block that can be used to implement most active and passive components. It differs from the operation amplifier in that it uses current instead of voltage. The current conveyor also has significantly higher voltage gain over a broader frequency range. To simplify the construction of analogue circuits and increase the construction efficiency it is desirable to use a top-down methodology. This means that the whole system is partitioned into a hierarchy of subsystems.

Prediktion av bostadsrättspriser i Stockholms innerstad.

A frequently asked question in real estate marketing is at what time of the year it is optimal to invest or sell. The aim of the project was to answer this question and to generate a prediction model over real estate located in the centre of Stockholm that takes seasons into account. With acquired sales statistics in Stockholm between 2010 and 2013 it was possible to perform a linear least square regression, also known as Ordinary Least Square (OLS), with describing qualities and season of sale as parameters. Statistical problems such as Multicollinearity and Heteroskedasticity have been taken into account when deriving the model. The result was a highly accurate prediction model indicating the profitability of investing in real estate during the summer and selling during the autumn..

En undersökning om fallolyckor med gångtrafikanter

The purpose of this study was to investigate different relations between the damages of falls and background variables as well as the relation between the falls and the weather condition to later be able to use this report to expand the knowledge among workers at VTI about the pedestrian fall injuries. All of the fall injuries in the data that this study is based on have occurred in Sweden during the time period between January 2003 and December 2011.To be able to answer the questions that this report is based on several statistical methods are used. The statistical methods that have been used during the making of this report are multiple linear regression, binary logistic regression, correlation analysis, association analysis and descriptive statistics as well as visual analysis.The results of the study show that women around menopause age have a tendency to get a big increase in the amount of injuries compared to men of the same age. The study also suggests that men on average tend to have a lower level of injury compared to women.Age also seems to affect both the amount of injuries and the level of injury negatively. The study suggests that the most likely reason for this is both that the intake of ?Fall Risk Increasing Medicine?, which is medicine that increases the drowsiness, is higher among older individuals as well as lower estrogen levels among older women and lower amount of testosterone among older men, which causes a loss of bone density in both sexes.The weather seems to have a strong effect on how many injuries occur but also a noticeable effect on the scale of the injury.

Flygbesiktning av Luftledningar : Modellering av samband mellan besiktningsanmärkningar och systemtillförlitlighet

This paper thoroughly investigates needs and requirements for overhead distribution feeder inspection and develops models to investigate possible relations between short term inspections remarks and outages. The study was conducted in collaboration with Fortum Distribution AB that supplied extensive information about their overhead power feeders concerning both inspection and power outages. The investigated models where lognormal linear model, Poisson generalized linear model and negative binomial generalized linear model. All models were implemented utilizing offset terms to compensate for differences in feeder length and amount of overhead versus underground feeders. The Poisson generalized linear model was rejected at an early stage due to overdispersion and neither of the remaining models fit the data perfectly.

Den svenska skogsindustrins beroende av makroprisvariabler

En analys av vilka makrovariabler som har störst påverkan på den svenska skogsindustrins lönsamhet. Fem företag och ett antal makroprisvariabler mätna under en tio-års period. Teoretiskt ramverk är MUST-analysen, multipel regression har använts för att gradera variablers relevans..

Utvärdering av den svenska cykelhjälmslagen för barn under 15 år : Analys av nationella trender i cykelrelaterade huvudskador mellan 1998-2011

Introduction: In January 2005, a nationwide mandatory bicycle helmet law for children under the age of 15 was introduced in Sweden. In the current study, the effect of this law was evaluated by analyzing national trends in hospital admissions due to bicycle-related head injuries during the period 1998-2011.Methods: An interrupted time-series design with segmented regression analysis was used to evaluate the intervention effect on head injuries as a percentage of all injuries (%HI) among cyclists in age- and sex-specific groups. Effect was measured as a change in level and/or slope of the trend at the time of legislation.Results: A total of 35261 cyclists (0-54 years) were hospitalized due to a bicycle injury during the study period. Linear regression analyses of the entire study period (not segmented) showed significant year-to-year decreases in the %HI of 1.3-1.7% in all age and sex-specific groups (p < .0001). Results from the segmented regression analysis showed that, at the time of legislation, a significant drop in level occurred among males under 15 years (-4.5% [95% CI: -7.7% to -1.3%], p = .01) and a significant change in slope occurred among females aged 30-54 years (-1.6% [95% CI: -2.9% to -0.2%], p = .025).Conclusions: The law seems to have had an effect on males in the target population (<15 years).

Utveckling och utvördering av statistiska metoder för att öka träffsäkerheten hos lokala vindprognoser

Wind is used as an energy source all over the world. To be able to use this effectively, there is a need for as good forecasts and forecast models as possible. One of these models is Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS®) that is used to calculate short time forecasts. This model is used here to calculate wind speeds at two different areas in Västra Götaland, Bengtsfors and Vänersborg. There are also wind measurements with SODAR stations for these areas.

Blankning-en studie av instrumentets effekter på Stockholmsbörsen

Purpose: The purpose of this study is to investigate possible links between short selling and the stock market movements using econometric test models. Methodology: A quantitative study carried out on the time series stock lending and OMX Stockholm 30 index. Information is gathered through qualitative interviews with specialists in the field of stock lending, and studies of relevant newspaper articles and reports. Theoretical approach: The theoretical frame of reference is a further consideration of supply and demand theory. The empirical study is implemented by the simple linear regression model and a vector autoregressive model (VAR).

Kreditklassning av aktiebolag i Sverige, en logistisk regression

Predicting corporate failure is an increasingly important topic in the world of economics today. This paper, with the help of the credit ranking company Syna AB, aims to investigate a few different statistic strategies to do just that. This task is accomplished by using a data material of 250 000 Swedish companies divided into two subsamples. The first sample is used to develop the model and the second as a validation sample. The model developing sample holds 160 000 companies divided into five different subgroups based on size and age.

Återköp av aktier på den svenska marknaden : Hur påverkar utestående optioner sannolikheten för aktieåterköp?

I mars år 2000 blev det tillåtet för börsnoterade bolag att genomföra återköp av egna aktier i Sverige. En del kritiker hävdar att återköp kan användas till att påverka aktiekursen positivt, till förmån för bland annat optionsinnehavare. I denna uppsats har vi undersökt om antal utestående optioner till anställda ökar sannolikheten för genomförandet av aktieåterköp. För att ta reda på detta har vi undersökt data från samtliga bolag som var noterade på NASDAQ OMX Large Cap i Stockholm vid utgången av år 2007. Vi har analyserat datamaterialet med hjälp av enkel linjär regression samt logistisk regression.

VEM ST?DJER BIST?NDET? En kvantitativ studie om vilka faktorer som p?verkar attityden gentemot EU:s internationella bist?nd

The discussion regarding international aid tends to be highly debated for long periods of time. Some individuals are very positive towards aid and some individuals are less positive towards aid. This study aims to broaden the understanding of the aspects behind that. The previous research tends to focus on aid allocation within the EU, or which macro factors could influence which donor countries give to which recipient countries. This study aims to add to the research with which aspects at the individual level can influence the individual's attitude towards international aid from the EU.

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