• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3010
  • 1002
  • 369
  • 345
  • 272
  • 182
  • 174
  • 160
  • 82
  • 54
  • 30
  • 29
  • 23
  • 22
  • 21
  • Tagged with
  • 6619
  • 2241
  • 1127
  • 915
  • 850
  • 791
  • 740
  • 738
  • 643
  • 541
  • 498
  • 486
  • 444
  • 417
  • 396
  • 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.
261

Förutsägelse av produktionskostnaden för svetsade konstruktioner / Prediction of production cost of welded structures

Sota, Emmanuel Perez, Qollakaj, Kushtrim January 2015 (has links)
Volvo Construction Equipment with headquarters in Eskilstuna is the world's oldest and one of the leading companies in the construction industry with products such articulated haulers, wheel loaders, excavators and skid steer loaders. The main purpose of this study is to create a tool for predicting the production cost of welded structures for the company's articulated haulers, which today is world leading on the market. To succeed, the study has been broken down in three problem areas in which the first one is to completely map out today's manufacturing process of the six basic components of the articulated hauler model A40 (A-Stay front, A-Stay rear, short and long rods and front and rear frame) for both manual and robotic welding. Account is taken to each weld in the manufacturing process and all costs incurred. Various types of welding measurements such as thread consumption for both manual and robotic welding, weld length for both manual and robotic welding is taken account to. The weld metal weight, arc time, robot degree length, deposition rate, price per meter, price per kilo and the total cost for each component has been measured and calculated. Next problem area starts from the identification of the manufacturing process and the purpose is to identify the largest cost culprits to lower manufacturing process costs and making the manufacturing process more efficient. As regards the third and final problem area on basis of the results from the two past problem areas regression is used to generate a mathematical formula that is used to predict the production of welded components for the company's articulated haulers. The final tool that is sought was created in form of a software by embedding the mathematical formula obtained from the regression. Now one can easily predict the production cost of welded structures by using the following tool. The only thing you need to do to predict any production cost of a welded structure is to enter the drawing welding weight, item weight, average welding length, proportion of butt weld percentage and the butt weld length for manual and robot welding. / Volvo Construction Equipment med huvudkontor i Eskilstuna är världens äldsta och en av världens ledande företag vad gäller anläggningsmaskiner som exempelvis dumprar, hjullastare, grävmaskiner och kompaktlastare. Syftet med detta arbete är att skapa ett verktyg för att kunna förutse produktionskostnaden för svetsade komponenter för företagets ramstyrda dumprar som idag är världsledande i sin klass. För att lyckas med projektet har man brutit ner syftet i tre problemområden där man först och främst kartlägger hela dagens tillverkningsprocess av de sex grundläggande delarna för dumpermodellen A40 (A-stag, Vågbalk, kort och långt stag samt fram och bakram) för både manuell och robot svetsning. Hänsyn tas till varje svets i tillverkningen och alla kostnader som uppstår. Man utför även olika typer av svetsmätningar som exempelvis trådförbrukning och total svetslängd för både manuell och robotsvetsning. Man beräknar även svetsgodsvikten, bågtidsfaktorn, robotgradlängden, insvetstalet, pris per meter, pris per kilo och totalkostnaden för varje objekt. Vid nästa steg utgår man från kartläggningen av tillverkningsprocessen och man identifierar de största kostnadsbovarna med syfte att sänka tillverkningskostnaderna och göra tillverkningen mer effektiv. Vad gäller tredje och sista steget med utgångspunkt från tidigare resultaten använder man regression för att generera en matematisk formel som man använder för att kunna förutse produktionskostnaden för svetsade komponenter för företagets ramstyrda dumprar. Det slutgiltiga verktyget som eftersöks skapades i form av en mjukvara för datorer genom att bädda in den matematiska formeln man erhöll från regressionen som bygger på resultaten av kartläggningarna. Nu kan man enkelt förutse produktionskostnaden av svetsade komponenter. Det enda man behöver göra för att förutsäga någon produktionskostnad av en svetsad komponent är att mata in ritningens svetsvikt, objektvikt, medelsvetslängd, andelen stumsvets i procent samt längden manuell och robot stum svets för den komponenten man vill förutsäga priset på. Nyckelord: Svetsgodsvikt, Svetsekonomi, Regression.
262

Quantification of stock option risks and returns

Feng, Haoqi, 1983- 12 November 2010 (has links)
Under mild assumptions, the expected returns of call options increase as the strike price becomes higher. Two ways to define option moneyness are the ratio of strike price to stock price (K/S ratio) and log(K/S)/σ. This paper examines the positive relationship between the call option returns and the correspondent risks by establishing linear models regarding the option returns and the two ratios. Furthermore, these ratios can be used to predict the option returns based on the regression models in practice. / text
263

Lp regression under general error distributions

Lai, Pik-ying., 黎碧瑩. January 2004 (has links)
published_or_final_version / abstract / toc / Statistics and Actuarial Science / Master / Master of Philosophy
264

Prisbildning på fastigheter : Vad kan en skattesänkning innebära?

Björkman, Gunilla, Gelinder, Kristian January 2008 (has links)
Denna uppsats behandlar hur prisbildningen på fastigheter ser ut i Sverige. Syftet är att analysera prisbildningsmekanismer för småhusmarknaden, speciellt fokus läggs på fastighetsskatten. Genom insamling av tidsseriedata på kvartalsnivå för åren 1990- 2007 för hela landet samt regionerna Stockholms län, Sydsverige och mellersta Norrland har regressioner genomförts för att studera olika variablers inverkan på småhuspriserna. Variablerna som studerats är hushållens inkomst, bolåneränta, fastighetsskatt, Affärsvärldens generalindex samt förgående års fastighetspris. Resultaten visar att skatten i viss mån påverkar prissättningen. Vidare konstateras att inkomsten är den viktigaste variabeln samt att bolåneräntan uppvisar signifikanta resultat för prispåverkan.
265

Robust estimation and testing : finite-sample properties and econometric applications

You, Jiazhong, 1968- January 2000 (has links)
High breakdown point, bounded influence and high efficiency at the Gaussian model are desired properties of robust regression estimators. Robustness of validity, robustness of efficiency and high breakdown point size and power are the fundamental goals in robust testing. The objective of this dissertation is to examine the finite-sample properties of robust estimators and tests, and to find some useful applications for them. This is accomplished by extensive Monte Carlo experiments and other inference techniques in various contamination situations. In the linear regression model with an outlying regressor and deviations from the normal error distribution, robust estimators demonstrate noticeable advantages over the standard LS and maximum likelihood (ML) estimators. Our findings reveal that the finite-sample behavior of the robust estimators is very different from their asymptotic properties. The robust properties of estimators carry over to test statistics based on these estimators. The robust tests we proposed can achieve to the large extent the fundamental goals in robust testing. Economic applications on modelling the household consumption behavior and testing for (G)ARCH effects show that one can capture big gains from the appropriate utilization of the robust methods even at very simple models.
266

Censored regression and the Pearson system of distributions : an estimation method and application to demand analysis

Izadi, Hooshang January 1989 (has links)
No description available.
267

Optimal mineral taxation in Manitoba: an exploration of Monte Carlo simulation analysis

Verhaeghe, Joseph Rene Stephen 10 September 2014 (has links)
Manitoba has abundant mineral deposits and the mining sector is significant for its economy, especially outside the capital region. This paper examines the Manitoba mining taxation regime, using two approaches. First, a conventional regression analysis is used to estimate the impact of the 2009 mining tax cut on Northern employment and capital investment. This approach potentially offers a general indication of how tax policy influences economic advantages. Unfortunately, data limitations impede the analysis. Second, a mining firm is modelled to directly examine the effect of various tax structures on profitability. A hypothetical underground mine is modelled using discounted cash flow and net present value methods. Monte Carlo simulation will add a further dimensionality to the analysis, evaluating the effects of taxation when making probability assumptions on metal grade, prices, and operating costs. The new mine tax holiday stands out as a significant tax benefit for the miner.
268

Informell äldreomsorg : En studie om vad som påverkar svenska individens informella omsorgsgivande av äldre närstående / Informal eldercare : A study of what affects Swedish individuals informal caregiving of elderly relatives

Strandqvist, Ida, Yxenholt, Louise January 2014 (has links)
Med formell omsorg menas offentlig vård- och omsorgsinsatser som oftast kommuner, landsting eller privaträttsliga företag på entreprenad utför. Med informell omsorg menar man anhörigomsorg som motsvarar insatser vid långvariga hjälpbehov och frivilliga insatser som innebär oavlönade arbetsuppgifter som man själv väljer att göra. Denna uppsats undersöker ifall variablerna kön, ålder, utbildning, anställning, inkomst, bostadsort samt barn i hemmet kan associeras med svenska individers utförande av informell omsorg av föräldrar eller svärföräldrar. Resultatet visar att om man har en hög utbildning så minskar sannolikheten för att man utför informell omsorg på sina föräldrar/svärföräldrar. Något som också minskar sannolikheten är om du har fler än ett barn under 18 år i hemmet, vilket kan ses som logiskt då barn kräver mycket tid. Något som istället ökar sannolikheten för att man utför informell omsorg är om man är anställd eller om man är i åldern 31-80 år. Undersökningen visar också att kön spelar roll då det framgick att kvinnor i större utsträckning utför informell omsorg. Resultaten stämmer inte helt överens med tidigare teorier och uppfattningar, vilket gör att vi kan konstatera att det är svårt att fastställa hur olika faktorer påverkar informell omsorg. / Formal care refers to public health and social care interventions that usually municipal, county or private sector company on contract performs. Informal care includes care provided by relatives that corresponds action when long-term assistance is needed and volunteer efforts involving unpaid duties that they themselves choose to do. This paper examines whether the variables gender, age, education, employment, income, place of residence and children in the home may be associated with Swedish individuals performing informal care by parents or in-laws. The result shows that if you have a high level of education the probability of performing informal care for their parents / in-laws decreases. Something that also reduces the probability is if you have more than one child under 18 at home, which can be seen as logical since children require much time. Something that instead increases the probability of performing informal care is if you are employed or if you are aged 31-80 years. The survey also shows that gender matters since it appeared that more women performing informal care. The results are not entirely consistent with previous theories and concepts, which enables us to conclude that it is difficult to determine how various factors affect the informal care.
269

Stagewise and stepwise regression techniques in meteorological forecasting

Hess, H. Allen January 1978 (has links)
No description available.
270

Personality and the prediction of work performance: artificial neural networks versus linear regression

Minbashian, Amirali, Psychology, Faculty of Science, UNSW January 2006 (has links)
Previous research that has evaluated the effectiveness of personality variables for predicting work performance has predominantly relied on methods designed to detect simple relationships. The research reported in this thesis employed artificial neural networks ??? a method that is capable of capturing complex nonlinear and configural relationships among variables ??? and the findings were compared to those obtained by the more traditional method of linear regression. Six datasets that comprise a range of occupations, personality inventories, and work performance measures were used as the basis of the analyses. A series of studies were conducted to compare the predictive performance of prediction equations that a) were developed using either artificial neural networks or linear regression, and b) differed with respect to the type and number of personality variables that were used as predictors of work performance. Studies 1 and 2 compared the two methods using individual personality variables that assess the broad constructs of the five-factor model of personality. Studies 3 and 4 used combinations of these broad variables as the predictors. Study 5 employed narrow personality variables that assess specific facets of the broad constructs. Additional methodological contributions include the use of a resampling procedure, the use of multiple measures of predictive performance, and the comparison of two procedures for developing neural networks. Across the studies, it was generally found that the neural networks were rarely able to outperform the simpler linear regression equations, and this was attributed to the lack of reliable nonlinearity and configurality in personality-work performance relationships. However, the neural networks were able to outperform linear regression in the few instances where there was some independent evidence of nonlinear or configural relationships. Consequently, although the findings do not support the usefulness of neural networks for specifically improving the effectiveness of personality variables as predictors of work performance, in a broader sense they provide some grounds for optimism for organisational researchers interested in applying this method to investigate and exploit complex relationships among variables.

Page generated in 0.162 seconds