1,761 research outputs found

    A New Load Residual Threshold Definition for the Evaluation of Wind Tunnel Strain-Gage Balance Data

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    A new definition of a threshold for the detection of load residual outliers of wind tunnel strain-gage balance data was developed. The new threshold is defined as the product between the inverse of the absolute value of the primary gage sensitivity and an empirical limit of the electrical outputs of a strain{gage. The empirical limit of the outputs is either 2.5 microV/V for balance calibration or check load residuals. A reduced limit of 0.5 microV/V is recommended for the evaluation of differences between repeat load points because, by design, the calculation of these differences removes errors in the residuals that are associated with the regression analysis of the data itself. The definition of the new threshold and different methods for the determination of the primary gage sensitivity are discussed. In addition, calibration data of a six-component force balance and a five-component semi-span balance are used to illustrate the application of the proposed new threshold definition to different types of strain{gage balances. During the discussion of the force balance example it is also explained how the estimated maximum expected output of a balance gage can be used to better understand results of the application of the new threshold definition

    Development of a User Interface for a Regression Analysis Software Tool

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    An easy-to -use user interface was implemented in a highly automated regression analysis tool. The user interface was developed from the start to run on computers that use the Windows, Macintosh, Linux, or UNIX operating system. Many user interface features were specifically designed such that a novice or inexperienced user can apply the regression analysis tool with confidence. Therefore, the user interface s design minimizes interactive input from the user. In addition, reasonable default combinations are assigned to those analysis settings that influence the outcome of the regression analysis. These default combinations will lead to a successful regression analysis result for most experimental data sets. The user interface comes in two versions. The text user interface version is used for the ongoing development of the regression analysis tool. The official release of the regression analysis tool, on the other hand, has a graphical user interface that is more efficient to use. This graphical user interface displays all input file names, output file names, and analysis settings for a specific software application mode on a single screen which makes it easier to generate reliable analysis results and to perform input parameter studies. An object-oriented approach was used for the development of the graphical user interface. This choice keeps future software maintenance costs to a reasonable limit. Examples of both the text user interface and graphical user interface are discussed in order to illustrate the user interface s overall design approach

    Banklojalitet blant studenter i Bergen : en empirisk undersøkelse

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    Formålet med denne utredningen er å kartlegge hvilke faktorer som gir lojale bankkunder blant studenter i Bergen. Resultatet kan gi banker innsikt i hva som har betydning for studentene for å bli værende som kunde i deres bank. Vi har derfor gjort oss opp noen tanker om hva som kan gjøres konkret for å skape lojale bankkunder med resultatene fra analysen som utgangspunkt. Datainnsamlingen til denne masterutredningen er gjort ved å personlig levere ut spørreskjemaer til studenter ved to høyskoler og et universitet i Bergen. Etter innsamling har dataene blitt tolket ved hjelp av statistikkprogrammet SPSS. Vi har gjort noen interessante funn som vi mener kan ha betydning for bankers markedsføring mot studenter i Bergen. I og med at det finnes over 27 000 studenter i denne byen kan det være en interessant målgruppe å rette fokuset mot. De viktigste funnene våre var at kundetilfredshet var den driveren som hadde størst betydning for studentenes lojalitet til banken. I tillegg hadde kundetilfredshet stor tilknytning til bankens rykte. Vi fant også ut at for kvinner var empati også viktig når det gjaldt lojalitet. For menn derimot så det ut til at søkekostnader hadde en negativ sammenheng med lojalitet. Vi erfarte at seks av forklaringsvariablene vi hadde med i forskningsmodellen ikke hadde innvirkning på lojaliteten, enten fordi de falt ut i faktoranalysen eller fordi de ikke var signifikante i regresjonsanalysen. Det medførte at en del av hypotesene våre ikke fikk støtte. Konklusjonen må derfor bli at det er nødvendig å fokusere på spesielt kundetilfredshet for å oppnå lojale kunder blant vår målgruppe. I tillegg kan det være hensiktsmessig å drive ulik markedsføring med hensyn på kjønn i forhold til empati og søkekostnader

    Fôropptak, produksjon og energiutnyttelse hos Norsk Rødt Fe (NRF) og Sidet Trønder og Nordlandsfe (STN) i rasjoner med og uten kraftfôr

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    Daglig opptak av surfôrtørrstoff, energi og protein var langt høgere hos NRF kyrne enn STN kyrne. NRF kyrne hadde også et påviselig høgere opptak av grovfôr og NDF enn STN kyrne uttrykt per 100 kg kroppsvekt.STN kyrne la mer på seg enn NRF kyrne, og kyrne som fikk kraftfôr la mer på seg enn kyr uten kraftfôr, men verken rase eller kraftfôrnivå hadde signifikant effekt på dyras vektendring. Det ble ikke påvist noen signifikante samspilleffekter mellom rase og kraftfôrnivå på noen av opptaksparametrene.Som forventet produserte NRF kyrne mer mjølk og EKM enn STN kyrne, men innholdet av fett og protein i mjølka var høgest hos STN kyrne. Daglig produksjon av fett og protein var imidlertid høgest hos NRF kyrne enn STN kyrne pga høgere mjølkeproduksjon. Hverken rase eller kraftfônivå viste signifikant forskjell på fôrutnytting, bruttoenergieffektivitet og partiell utnytting av fôrenergien til mjølkeproduksjo

    Regression Analysis and Calibration Recommendations for the Characterization of Balance Temperature Effects

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    Analysis and use of temperature-dependent wind tunnel strain-gage balance calibration data are discussed in the paper. First, three different methods are presented and compared that may be used to process temperature-dependent strain-gage balance data. The first method uses an extended set of independent variables in order to process the data and predict balance loads. The second method applies an extended load iteration equation during the analysis of balance calibration data. The third method uses temperature-dependent sensitivities for the data analysis. Physical interpretations of the most important temperature-dependent regression model terms are provided that relate temperature compensation imperfections and the temperature-dependent nature of the gage factor to sets of regression model terms. Finally, balance calibration recommendations are listed so that temperature-dependent calibration data can be obtained and successfully processed using the reviewed analysis methods

    Evaluation of Regression Models of Balance Calibration Data Using an Empirical Criterion

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    An empirical criterion for assessing the significance of individual terms of regression models of wind tunnel strain gage balance outputs is evaluated. The criterion is based on the percent contribution of a regression model term. It considers a term to be significant if its percent contribution exceeds the empirical threshold of 0.05%. The criterion has the advantage that it can easily be computed using the regression coefficients of the gage outputs and the load capacities of the balance. First, a definition of the empirical criterion is provided. Then, it is compared with an alternate statistical criterion that is widely used in regression analysis. Finally, calibration data sets from a variety of balances are used to illustrate the connection between the empirical and the statistical criterion. A review of these results indicated that the empirical criterion seems to be suitable for a crude assessment of the significance of a regression model term as the boundary between a significant and an insignificant term cannot be defined very well. Therefore, regression model term reduction should only be performed by using the more universally applicable statistical criterion

    Wind Tunnel Strain-Gage Balance Calibration Data Analysis Using a Weighted Least Squares Approach

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    A new approach is presented that uses a weighted least squares fit to analyze wind tunnel strain-gage balance calibration data. The weighted least squares fit is specifically designed to increase the influence of single-component loadings during the regression analysis. The weighted least squares fit also reduces the impact of calibration load schedule asymmetries on the predicted primary sensitivities of the balance gages. A weighting factor between zero and one is assigned to each calibration data point that depends on a simple count of its intentionally loaded load components or gages. The greater the number of a data point's intentionally loaded load components or gages is, the smaller its weighting factor becomes. The proposed approach is applicable to both the Iterative and Non-Iterative Methods that are used for the analysis of strain-gage balance calibration data in the aerospace testing community. The Iterative Method uses a reasonable estimate of the tare corrected load set as input for the determination of the weighting factors. The Non-Iterative Method, on the other hand, uses gage output differences relative to the natural zeros as input for the determination of the weighting factors. Machine calibration data of a six-component force balance is used to illustrate benefits of the proposed weighted least squares fit. In addition, a detailed derivation of the PRESS residuals associated with a weighted least squares fit is given in the appendices of the paper as this information could not be found in the literature. These PRESS residuals may be needed to evaluate the predictive capabilities of the final regression models that result from a weighted least squares fit of the balance calibration data
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