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1
Arledge, Christopher S. "Cosmological Model Selection and Akaike’s Criterion." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1430478203.
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Coleman, Kimberley. "A new capture-recapture model selection criterion /." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101841.
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Capture-recapture methods are used to estimate population size from overlapping, incomplete sources of information. With three or more sources, dependence between sources may be modelled using log-linear models. We propose a Coefficient of Incremental Dependence Criterion (CIDC) for selecting an estimate of population size among all possible estimates that result from hierarchical log-linear models. A penalty for the number of parameters in the model was selected via simulation for the three-source and four-source settings. The performance of the proposed criterion was compared to the Akaike Information Criterion (AIC) through simulation. The CIDC was found to modestly outperform the AIC for data generated from a population size of approximately 100, with AIC performing consistently better for larger population sizes. Modifications to the criterion such as incorporating the estimated population size and the type of source interaction present should be investigated, along with the mathematical properties of the CIDC.
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Wikström, Christina. "Criterion-referenced measurement for educational evaluation and selection." Doctoral thesis, Umeå universitet, Beteendevetenskapliga mätningar, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-492.
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In recent years, Sweden has adopted a criterion-referenced grading system, where the grade outcome is used for several purposes, but foremost for educational evaluation on student- and school levels as well as for selection to higher education. This thesis investigates the consequences of using criterion-referenced measurement for both educational evaluation and selection purposes. The thesis comprises an introduction and four papers that empirically investigate school grades and grading practices in Swedish upper secondary schools. The first paper investigates the effect of school competition on the school grades. The analysis focuses on how students in schools with and without competition are ranked, based on their grades and SweSAT scores. The results show that schools that are exposed to competition tend to grade their students higher than other schools. This effect is found to be related to the use of grades as quality indicators for the schools, which means that schools that compete for their students tend to be more lenient, hence inflating the grades. The second paper investigates grade averages over a six-year period, starting with the first cohort who graduated from upper secondary school with a GPA based on criterion-referenced grades. The results show that grades have increased every year since the new grading system was introduced, which cannot be explained by improved performances, selection effects or strategic course choices. The conclusion is that the increasing pressure for high grading has led to grade inflation over time. The third paper investigates if grading practices are related to school size. The study is based on a similar model as paper I, but with data from graduates over a six-year period, and with school size as the main focus. The results show small but significant size effects, suggesting that the smallest schools (<300 students) are higher grading than other schools, and that the largest schools (>1000 students) are lower grading than other schools. This is assumed to be an effect of varying assessment practices, in combination with external and internal pressure for high grading. The fourth and final paper investigates if grading practices differ among upper secondary programmes, and how the course compositions in the programmes affect how students are ranked in the process of selection to higher education. The results show that students in vocationally oriented programmes are higher graded than other students, and also favoured by their programmes’ course compositions, which have a positive effect on their competitive strength in the selection to higher education. In the introductory part of the thesis, these results are discussed from the perspective of a theoretical framework, with special attention to validity issues in a broad perspective. The conclusion is that the criterion-referenced grades, both in terms of being used for educational evaluation, and as an instrument for selection to higher education, are wanting both in reliability and in validity. This is related to the conflicting purposes of the instruments, in combination with few control mechanisms, which affects how grades are interpreted and used, hence leading to consequences for students, schools and society in general.
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Fanai, Nick. "Reversibility as a sustainability criterion for project selection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq23297.pdf.
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Wikström, Christina. "Criterion-referenced measurement for educational evaluation and selection /." Umeå : Department of Educational Measurement, Umeå University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-492.
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Atutey, Olivia Abena. "Linear Mixed Model Selection via Minimum Approximated Information Criterion." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1594910831256966.
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Lin, Hui-Fen. "A Comparison of Three Item Selection Methods in Criterion-Referenced Tests." Thesis, University of North Texas, 1988. https://digital.library.unt.edu/ark:/67531/metadc332327/.
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This study compared three methods of selecting the best discriminating test items and the resultant test reliability of mastery/nonmastery classifications. These three methods were (a) the agreement approach, (b) the phi coefficient approach, and (c) the random selection approach.
Test responses from 1,836 students on a 50-item physical science test were used, from which 90 distinct data sets were generated for analysis. These 90 data sets contained 10 replications of the combination of three different sample sizes (75, 150, and 300) and three different numbers of test items (15, 25, and 35).
The results of this study indicated that the agreement approach was an appropriate method to be used for selecting criterion-referenced test items at the classroom level, while the phi coefficient approach was an appropriate method to be used at the district and/or state levels. The random selection method did not have similar characteristics in selecting test items and produced the lowest reliabilities, when compared with the agreement and the phi coefficient approaches.
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Levine, Anne B. "The Structured Employment Interview: An Examination of Construct and Criterion Validity." The University of Waikato, 2006. http://hdl.handle.net/10289/2288.
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This study extends the literature on interview validity by attempting to create a structured employment interview with both construct- and criterion-related validity. For this study, a situational interview was developed with the specific purpose of enhancing the interview's construct validity while retaining the interview's predictive power. To enhance the construct validity, two guidelines were applied to the creation of the interview based on previous research in interview and assessment center literature limit the number of applicant characteristics to be rated to 3; and (2) ensure that the dimensions to be measured are conceptually distinct. Based on these two guidelines, three constructs were chosen for assessment of real estate sales agents extraversion, proactive personality and customer orientation. The critical incident technique was used to develop six interview items. To test the construct validity of the interview, the six items were correlated with other measures, specifically, self-report questionnaires and managers' ratings, of extraversion, proactivity and customer orientation. Correlations were weak, at best (rs ranged from -.06 to .25). To test the predictive validity of the interview, the six items were correlated with both objective and subjective measures of performance. Predictive validities were stronger, ranging from .23 to .30. These findings are consistent with previous research on employment interviews which have found that although the predictive validity of the interview is strong, the construct validity is very weak, leaving researchers to wonder what it is that the interview is actually measuring. Possible explanations for these findings are offered, and the implications of these findings are discussed.
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TAKAGI, HIROSHI, AKIRA ORIHARA, KAZUHARU UCHIDA, ITSUO YOKOYAMA, and TAKAAKI KOBAYASHI. "HLA-DRB1 Matching As A Recipient Selection Criterion in Cadaveric Renal Transplantation." Thesis, Lippincott Williams & Wilkins, 1993. http://hdl.handle.net/2237/19377.
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MONTEIRO, ANDRE MONTEIRO DALMEIDA. "NON-PARAMETRIC ESTIMATIONS OF INTEREST RATE CURVES : MODEL SELECTION CRITERION: MODEL SELECTION CRITERIONPERFORMANCE DETERMINANT FACTORS AND BID-ASK S." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=2684@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROEsta tese investiga a estimação de curvas de juros sob o ponto de vista de métodos não-paramétricos. O texto está dividido em dois blocos. O primeiro investiga a questão do critério utilizado para selecionar o método de melhor desempenho na tarefa de interpolar a curva de juros brasileira em uma dada amostra. Foi proposto um critério de seleção de método baseado em estratégias de re-amostragem do tipo leave-k-out cross validation, onde K k £ £ 1 e K é função do número de contratos observados a cada curva da amostra. Especificidades do problema reduzem o esforço computacional requerido, tornando o critério factível. A amostra tem freqüência diária: janeiro de 1997 a fevereiro de 2001. O critério proposto apontou o spline cúbico natural -utilizado com método de ajuste perfeito aos dados - como o método de melhor desempenho. Considerando a precisão de negociação, este spline mostrou-se não viesado. A análise quantitativa de seu desempenho identificou, contudo, heterocedasticidades nos erros simulados. A partir da especificação da variância condicional destes erros e de algumas hipóteses, foi proposto um esquema de intervalo de segurança para a estimação de taxas de juros pelo spline cúbico natural, empregado como método de ajuste perfeito aos dados. O backtest sugere que o esquema proposto é consistente, acomodando bem as hipóteses e aproximações envolvidas. O segundo bloco investiga a estimação da curva de juros norte-americana construída a partir dos contratos de swaps de taxas de juros dólar-Libor pela Máquina de Vetores Suporte (MVS), parte do corpo da Teoria do Aprendizado Estatístico. A pesquisa em MVS tem obtido importantes avanços teóricos, embora ainda sejam escassas as implementações em problemas reais de regressão. A MVS possui características atrativas para a modelagem de curva de juros: é capaz de introduzir já na estimação informações a priori sobre o formato da curva e sobre aspectos da formação das taxas e liquidez de cada um dos contratos a partir dos quais ela é construída. Estas últimas são quantificadas pelo bid-ask spread (BAS) de cada contrato. A formulação básica da MVS é alterada para assimilar diferentes valores do BAS sem que as propriedades dela sejam perdidas. É dada especial atenção ao levantamento de informação a priori para seleção dos parâmetros da MVS a partir do formato típico da curva. A amostra tem freqüência diária: março de 1997 a abril de 2001. Os desempenhos fora da amostra de diversas especificações da MVS foram confrontados com aqueles de outros métodos de estimação. A MVS foi o método que melhor controlou o trade- off entre viés e variância dos erros.
This thesis investigates interest rates curve estimation under non-parametric approach. The text is divided into two parts. The first one focus on which criterion to use to select the best performance method in the task of interpolating Brazilian interest rate curve. A selection criterion is proposed to measure out-of-sample performance by combining resample strategies leave-k-out cross validation applied upon the whole sample curves, where K k £ £ 1 and K is function of observed contract number in each curve. Some particularities reduce substantially the required computational effort, making the proposed criterion feasible. The data sample range is daily, from January 1997 to February 2001. The proposed criterion selected natural cubic spline, used as data perfect-fitting estimation method. Considering the trade rate precision, the spline is non-biased. However, quantitative analysis of performance determinant factors showed the existence of out-of-sample error heteroskedasticities. From a conditional variance specification of these errors, a security interval scheme is proposed for interest rate generated by perfect-fitting natural cubic spline. A backtest showed that the proposed security interval is consistent, accommodating the evolved assumptions and approximations. The second part estimate US free-for-floating interest rate swap contract curve by using Support Vector Machine (SVM), a method derived from Statistical Learning Theory. The SVM research has got important theoretical results, however the number of implementation on real regression problems is low. SVM has some attractive characteristics for interest rates curves modeling: it has the ability to introduce already in its estimation process a priori information about curve shape and about liquidity and price formation aspects of the contracts that generate the curve. The last information set is quantified by the bid-ask spread. The basic SVM formulation is changed in order to be able to incorporate the different values for bid-ask spreads, without losing its properties. Great attention is given to the question of how to extract a priori information from swap curve typical shape to be used in MVS parameter selection. The data sample range is daily, from March 1997 to April 2001. The out-of-sample performances of different SVM specifications are faced with others method performances. SVM got the better control of trade- off between bias and variance of out-of-sample errors.
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Kroeger, Heidelore Irene. "Development of a risk measure as a project selection criterion for sustainable development." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq23372.pdf.
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Sharp, Gary David. "Lag length selection for vector error correction models." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1002808.
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This thesis investigates the problem of model identification in a Vector Autoregressive framework. The study reviews the existing research, conducts an extensive simulation based analysis of thirteen information theoretic criterion (IC), one of which is a novel derivation. The simulation exercise considers the evaluation of seven alternative error restricted vector autoregressive models with four different lag lengths. Alternative sample sizes and parameterisations are also evaluated and compared to results in the existing literature. The results of the comparative analysis provide strong support for the efficiency based criterion of Akaike and in particular the selection capability of the novel criterion, referred to as a modified corrected Akaike information criterion, demonstrates useful finite sample properties.
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Cabrera, Elizabeth Fraser. "Development and application of a new utility model for dichotomized criterion." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/29392.
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Kircher, Andrew J. "Estimation of the Squared Population Cross-Validity Under Conditions of Predictor Selection." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1472.
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The current study employed a Monte Carlo design to examine whether samplebased and formula-based estimates of cross-validated R2 differ in accuracy when predictor selection is and is not performed. Analyses were conducted on three datasets with 5, 10, or 15 predictors and different predictor-criterion relationships. Results demonstrated that, in most cases, a formula-based estimate of the cross-validated R2 was as accurate as a sample-based estimate. The one exception was the five predictor case wherein the formula-based estimate exhibited substantially greater bias than the estimate from a sample-based cross validation study. Thus, formula-based estimates, which have an enormous practical advantage over a two sample cross validation study, can be used in most cases without fear of greater error.
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Yoshimura, Arihiro. "Essays on Semiparametric Model Selection and Model Averaging." Kyoto University, 2015. http://hdl.handle.net/2433/199059.
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Carter, Knute Derek. "Best-subset model selection based on multitudinal assessments of likelihood improvements." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/5726.
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Given a set of potential explanatory variables, one model selection approach is to select the best model, according to some criterion, from among the collection of models defined by all possible subsets of the explanatory variables. A popular procedure that has been used in this setting is to select the model that results in the smallest value of the Akaike information criterion (AIC). One drawback in using the AIC is that it can lead to the frequent selection of overspecified models. This can be problematic if the researcher wishes to assert, with some level of certainty, the necessity of any given variable that has been selected.
This thesis develops a model selection procedure that allows the researcher to nominate, a priori, the probability at which overspecified models will be selected from among all possible subsets. The procedure seeks to determine if the inclusion of each candidate variable results in a sufficiently improved fitting term, and hence is referred to as the SIFT procedure. In order to determine whether there is sufficient evidence to retain a candidate variable or not, a set of threshold values are computed. Two procedures are proposed: a naive method based on a set of restrictive assumptions; and an empirical permutation-based method.
Graphical tools have also been developed to be used in conjunction with the SIFT procedure. The graphical representation of the SIFT procedure clarifies the process being undertaken. Using these tools can also assist researchers in developing a deeper understanding of the data they are analyzing.
The naive and empirical SIFT methods are investigated by way of simulation under a range of conditions within the standard linear model framework. The performance of the SIFT methodology is compared with model selection by minimum AIC; minimum Bayesian Information Criterion (BIC); and backward elimination based on p-values. The SIFT procedure is found to behave as designed—asymptotically selecting those variables that characterize the underlying data generating mechanism, while limiting the selection of false or spurious variables to the desired level.
The SIFT methodology offers researchers a promising new approach to model selection, whereby they are now able to control the probability of selecting an overspecified model to a level that best suits their needs.
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Wang, Wen-Chyi. "Regularized variable selection in proportional hazards model using area under receiver operating characteristic curve criterion." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9972.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Mathematics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Wang, Pei. "Simultaneously solving process selection, machining parameter optimization and tolerance design problems: A bi-criterion approach." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26544.
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The selection of right process, use of optimal machining parameters and specification of best tolerance parameters have been recognized by industry as key issues to ensure product quality and reduce production cost. The three issues have thus attracted a great deal of attention over last several decades. However, they are often addressed separately in existing publications. In reality, the three issues are closely interrelated. Analyzing the three issues in isolation will inevitably lead to inconsistent, infeasible, or conflicting decisions. To avoid the drawbacks, an integrated approach is proposed to jointly solve process selection, machining parameter optimization, and tolerance design problems. The integrated problem is formulated as a bi-criterion model to handle both tangible and intangible costs. The model is solved using a modified Chebyshev goal programming method to achieve a preferred compromise between the two conflicting criteria.
The application of the proposed bi-criterion approach has been demonstrated by first using the single component single part feature case. The integrated approach is then extended to the multiple components multiple part features case (the assembly case).
Examples are provided to illustrate the application of the two models and the solution procedure. The results have shown that the decisions on process selection, machining parameter selection and tolerance design can be made simultaneously using the models.
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Sofer, Tamar. "Statistical Methods for High Dimensional Data in Environmental Genomics." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10403.
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In this dissertation, we propose methodology to analyze high dimensional genomics data, in which the observations have large number of outcome variables, in addition to exposure variables. In the Chapter 1, we investigate methods for genetic pathway analysis, where we have a small number of exposure variables. We propose two Canonical Correlation Analysis based methods, that select outcomes either sequentially or by screening, and show that the performance of the proposed methods depend on the correlation between the genes in the pathway. We also propose and investigate criterion for fixing the number of outcomes, and a powerful test for the exposure effect on the pathway. The methodology is applied to show that air pollution exposure affects gene methylation of a few genes from the asthma pathway. In Chapter 2, we study penalized multivariate regression as an efficient and flexible method to study the relationship between large number of covariates and multiple outcomes. We use penalized likelihood to shrink model parameters to zero and to select only the important effects. We use the Bayesian Information Criterion (BIC) to select tuning parameters for the employed penalty and show that it chooses the right tuning parameter with high probability. These are combined in the “two-stage procedure”, and asymptotic results show that it yields consistent, sparse and asymptotically normal estimator of the regression parameters. The method is illustrated on gene expression data in normal and diabetic patients. In Chapter 3 we propose a method for estimation of covariates-dependent principal components analysis (PCA) and covariance matrices. Covariates, such as smoking habits, can affect the variation in a set of gene methylation values. We develop a penalized regression method that incorporates covariates in the estimation of principal components. We show that the parameter estimates are consistent and sparse, and show that using the BIC to select the tuning parameter for the penalty functions yields good models. We also propose the scree plot residual variance criterion for selecting the number of principal components. The proposed procedure is implemented to show that the first three principal components of genes methylation in the asthma pathway are different in people who did not smoke, and people who did.
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Scarborough, David J. (David James). "An Evaluation of Backpropagation Neural Network Modeling as an Alternative Methodology for Criterion Validation of Employee Selection Testing." Thesis, University of North Texas, 1995. https://digital.library.unt.edu/ark:/67531/metadc277752/.
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Employee selection research identifies and makes use of associations between individual differences, such as those measured by psychological testing, and individual differences in job performance. Artificial neural networks are computer simulations of biological nerve systems that can be used to model unspecified relationships between sets of numbers. Thirty-five neural networks were trained to estimate normalized annual revenue produced by telephone sales agents based on personality and biographic predictors using concurrent validation data (N=1085). Accuracy of the neural estimates was compared to OLS regression and a proprietary nonlinear model used by the participating company to select agents.
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Rumantir, Grace Widjaja. "Minimum message length criterion for second-order polynomial model selection applied to tropical cyclone intensity forecasting." Monash University, School of Computer Science and Software Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5813.
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Uys, Daniel Wilhelm. "Influential data cases when the C-p criterion is used for variable selection in multiple linear regression." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53464.
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Dissertation (PhD)--Stellenbosch University, 2003.ENGLISH ABSTRACT: In this dissertation we study the influence of data cases when the Cp criterion of Mallows (1973) is used for variable selection in multiple linear regression. The influence is investigated in terms of the predictive power and the predictor variables included in the resulting model when variable selection is applied. In particular, we focus on the importance of identifying and dealing with these so called selection influential data cases before model selection and fitting are performed. For this purpose we develop two new selection influence measures, both based on the Cp criterion. The first measure is specifically developed to identify individual selection influential data cases, whereas the second identifies subsets of selection influential data cases. The success with which these influence measures identify selection influential data cases, is evaluated in example data sets and in simulation. All results are derived in the coordinate free context, with special application in multiple linear regression.
AFRIKAANSE OPSOMMING: Invloedryke waarnemings as die C-p kriterium vir veranderlike seleksie in meervoudigelineêre regressie gebruik word: In hierdie proefskrif ondersoek ons die invloed van waarnemings as die Cp kriterium van Mallows (1973) vir veranderlike seleksie in meervoudige lineêre regressie gebruik word. Die invloed van waarnemings op die voorspellingskrag en die onafhanklike veranderlikes wat ingesluit word in die finale geselekteerde model, word ondersoek. In besonder fokus ons op die belangrikheid van identifisering van en handeling met sogenaamde seleksie invloedryke waarnemings voordat model seleksie en passing gedoen word. Vir hierdie doel word twee nuwe invloedsmaatstawwe, albei gebaseer op die Cp kriterium, ontwikkel. Die eerste maatstaf is spesifiek ontwikkelom die invloed van individuele waarnemings te meet, terwyl die tweede die invloed van deelversamelings van waarnemings op die seleksie proses meet. Die sukses waarmee hierdie invloedsmaatstawwe seleksie invloedryke waarnemings identifiseer word beoordeel in voorbeeld datastelle en in simulasie. Alle resultate word afgelei binne die koërdinaatvrye konteks, met spesiale toepassing in meervoudige lineêre regressie.
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Lehmann, Rüdiger, and Michael Lösler. "Multiple Outlier Detection: Hypothesis Tests versus Model Selection by Information Criteria." Hochschule für Technik und Wirtschaft Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:520-qucosa-225770.
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The detection of multiple outliers can be interpreted as a model selection problem. Models that can be selected are the null model, which indicates an outlier free set of observations, or a class of alternative models, which contain a set of additional bias parameters. A common way to select the right model is by using a statistical hypothesis test. In geodesy data snooping is most popular. Another approach arises from information theory. Here, the Akaike information criterion (AIC) is used to select an appropriate model for a given set of observations. The AIC is based on the Kullback-Leibler divergence, which describes the discrepancy between the model candidates. Both approaches are discussed and applied to test problems: the fitting of a straight line and a geodetic network. Some relationships between data snooping and information criteria are discussed. When compared, it turns out that the information criteria approach is more simple and elegant. Along with AIC there are many alternative information criteria for selecting different outliers, and it is not clear which one is optimal.
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Moore, Jason S. "THE EFFECTS OF DIVERSITY INITIATIVES ON THE DISTORTION OF APPLICANT QUALIFICATIONS AND DECISION STANDARDS." Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1162227465.
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Lehmann, Rüdiger, and Michael Lösler. "Multiple Outlier Detection: Hypothesis Tests versus Model Selection by Information Criteria." Hochschule für Technik und Wirtschaft Dresden, 2016. https://htw-dresden.qucosa.de/id/qucosa%3A23307.
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The detection of multiple outliers can be interpreted as a model selection problem. Models that can be selected are the null model, which indicates an outlier free set of observations, or a class of alternative models, which contain a set of additional bias parameters. A common way to select the right model is by using a statistical hypothesis test. In geodesy data snooping is most popular. Another approach arises from information theory. Here, the Akaike information criterion (AIC) is used to select an appropriate model for a given set of observations. The AIC is based on the Kullback-Leibler divergence, which describes the discrepancy between the model candidates. Both approaches are discussed and applied to test problems: the fitting of a straight line and a geodetic network. Some relationships between data snooping and information criteria are discussed. When compared, it turns out that the information criteria approach is more simple and elegant. Along with AIC there are many alternative information criteria for selecting different outliers, and it is not clear which one is optimal.
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Silva, Fernando Augusto Boeira Sabino da. "Additive nonparametric regression estimation via back tting and marginal integration under common bandwidth selection criterion : small sample performance." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/109669.
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In this paper, we conducted a Monte Carlo investigation to reveal some charac- teristics of
nite sample distributions of the back
tting (B) and Marginal Integration (MI) estimators for an additive bivariate regression. We are particularly interested in providing some evidence on how the di¤erent methods for the selection of bandwidth, such as the plug-in method, inuence the
nite sample properties of the MI and B estimators. We are particularly concerned with the performance of these estimators when bandwidth selection is done based in data driven methods, since in this case the aymptotics properties of these estimators are currently unavailable. The impact of ignoring the dependency between regressors is also investigated. Finally, di¤erently from what occurs at the present time, when the B and MI estimators are used ad-hoc, our objective is to provide information that allows for a more accurate comparison of these two competing alternatives in a
nite sample setting.
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Jayakumar, Vivek. "Optimal Sensor Locations Using Exact Modal Reduction." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623250902608798.
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Thanos, Anastasios. "A Study of Network assisted Device-to-Device Discovery Algorithms, a Criterion for Mode Selection and a Resource Allocation Scheme." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128372.
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Device-to-Device (D2D) communications is a term used to describe the new technology that allows two devices to communicate with each other directly, without using the base stations or the access points of the network infrastructure. D2D communication leads to better network performance for a number of reasons. Among the challenges of D2D communications are, the discovery of a new D2D communication pair, a criterion for mode selection and the optimum resource allocation for the new D2D pair. The discovery process of the new D2D pair includes transmissions of a number of messages that will provide the network with all the necessary information which will be used by the mode selection criterion and determine whether the new pair will use D2D or traditional cellular communication. The possibility of Network Assited Device-to-Device Communication, underlaying a cellular network is deliberated in this paper. Specically, two discovery algorithms are developped, one Centralized, Fully-Network Dependent discovery algorithm and a second Semi-Centralized, Semi-Network Dependent discovery algorithm are introduced and a comparative analysis of both is performed and presented. The criteria used for the evaluation of the Discovery Algorithms are time eciency and signal overhead. The results show that the second algorithm is faster in discovering new D2D pairs and requires minimum number of message exchanges. Moreover, the second algorithm is more ecient than the rst one, in case that the new pair is found not to be D2D. In addition, the importance of a Selection Criterion that allows the eN-odeB to decide whether traditional Cellular or D2D Communication between a pair of devices should be used is addressed. An optimum criterion, in terms of maximizing the total achieved throughput, is suggested and results are analyzed and evaluated. Results show that the proposed criterion is eective in performing mode selection for the new pair. Results are present in many dierent scenarios in order to provide generalizability to the new criterion.
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Frondana, Iara Moreira. "Model selection for discrete Markov random fields on graphs." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/45/45133/tde-02022018-151123/.
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In this thesis we propose to use a penalized maximum conditional likelihood criterion to estimate the graph of a general discrete Markov random field. We prove the almost sure convergence of the estimator of the graph in the case of a finite or countable infinite set of variables. Our method requires minimal assumptions on the probability distribution and contrary to other approaches in the literature, the usual positivity condition is not needed. We present several examples with a finite set of vertices and study the performance of the estimator on simulated data from theses examples. We also introduce an empirical procedure based on k-fold cross validation to select the best value of the constant in the estimators definition and show the application of this method in two real datasets.Nesta tese propomos um critério de máxima verossimilhança penalizada para estimar o grafo de dependência condicional de um campo aleatório Markoviano discreto. Provamos a convergência quase certa do estimador do grafo no caso de um conjunto finito ou infinito enumerável de variáveis. Nosso método requer condições mínimas na distribuição de probabilidade e contrariamente a outras abordagens da literatura, a condição usual de positividade não é necessária. Introduzimos alguns exemplos com um conjunto finito de vértices e estudamos o desempenho do estimador em dados simulados desses exemplos. Também propomos um procedimento empírico baseado no método de validação cruzada para selecionar o melhor valor da constante na definição do estimador, e mostramos a aplicação deste procedimento em dois conjuntos de dados reais.
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Lehmann, Rüdiger. "Observation error model selection by information criteria vs. normality testing." Hochschule für Technik und Wirtschaft Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:520-qucosa-211721.
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To extract the best possible information from geodetic and geophysical observations, it is necessary to select a model of the observation errors, mostly the family of Gaussian normal distributions. However, there are alternatives, typically chosen in the framework of robust M-estimation. We give a synopsis of well-known and less well-known models for observation errors and propose to select a model based on information criteria. In this contribution we compare the Akaike information criterion (AIC) and the Anderson Darling (AD) test and apply them to the test problem of fitting a straight line. The comparison is facilitated by a Monte Carlo approach. It turns out that the model selection by AIC has some advantages over the AD test.
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Lehmann, Rüdiger. "Observation error model selection by information criteria vs. normality testing." Hochschule für Technik und Wirtschaft Dresden, 2015. https://htw-dresden.qucosa.de/id/qucosa%3A23301.
Full textAbstract:
To extract the best possible information from geodetic and geophysical observations, it is necessary to select a model of the observation errors, mostly the family of Gaussian normal distributions. However, there are alternatives, typically chosen in the framework of robust M-estimation. We give a synopsis of well-known and less well-known models for observation errors and propose to select a model based on information criteria. In this contribution we compare the Akaike information criterion (AIC) and the Anderson Darling (AD) test and apply them to the test problem of fitting a straight line. The comparison is facilitated by a Monte Carlo approach. It turns out that the model selection by AIC has some advantages over the AD test.
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Fowler, Philip, and Pernilla Lindblad. "The Minimum Description Length principle in model selection : An evaluation of the renormalized maximum likelihood criterion in linear- and logistic regression analysis." Thesis, Umeå universitet, Statistiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-49707.
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Lehmann, Rüdiger. "Transformation model selection by multiple hypotheses testing." Hochschule für Technik und Wirtschaft Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:520-qucosa-211719.
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Transformations between different geodetic reference frames are often performed such that first the transformation parameters are determined from control points. If in the first place we do not know which of the numerous transformation models is appropriate then we can set up a multiple hypotheses test. The paper extends the common method of testing transformation parameters for significance, to the case that also constraints for such parameters are tested. This provides more flexibility when setting up such a test. One can formulate a general model with a maximum number of transformation parameters and specialize it by adding constraints to those parameters, which need to be tested. The proper test statistic in a multiple test is shown to be either the extreme normalized or the extreme studentized Lagrange multiplier. They are shown to perform superior to the more intuitive test statistics derived from misclosures. It is shown how model selection by multiple hypotheses testing relates to the use of information criteria like AICc and Mallows’ Cp, which are based on an information theoretic approach. Nevertheless, whenever comparable, the results of an exemplary computation almost coincide.
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Lehmann, Rüdiger. "Transformation model selection by multiple hypotheses testing." Hochschule für Technik und Wirtschaft Dresden, 2014. https://htw-dresden.qucosa.de/id/qucosa%3A23299.
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Transformations between different geodetic reference frames are often performed such that first the transformation parameters are determined from control points. If in the first place we do not know which of the numerous transformation models is appropriate then we can set up a multiple hypotheses test. The paper extends the common method of testing transformation parameters for significance, to the case that also constraints for such parameters are tested. This provides more flexibility when setting up such a test. One can formulate a general model with a maximum number of transformation parameters and specialize it by adding constraints to those parameters, which need to be tested. The proper test statistic in a multiple test is shown to be either the extreme normalized or the extreme studentized Lagrange multiplier. They are shown to perform superior to the more intuitive test statistics derived from misclosures. It is shown how model selection by multiple hypotheses testing relates to the use of information criteria like AICc and Mallows’ Cp, which are based on an information theoretic approach. Nevertheless, whenever comparable, the results of an exemplary computation almost coincide.
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Yamanouchi, Tatiana Kazue. "Seleção de modelos lineares mistos utilizando critérios de informação." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-08032018-131129/.
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O modelo misto é comumente utilizado em dados de medidas repetidas devido a sua flexibilidade de incorporar no modelo a correlação existente entre as observações medidas no mesmo indivíduo e a heterogeneidade de variâncias das observações feitas ao longo do tempo. Este modelo é composto de efeitos fixos, efeitos aleatórios e o erro aleatório e com isso na seleção do modelo misto muitas vezes é necessário selecionar os melhores componentes do modelo misto de tal forma que represente bem os dados. Os critérios de informação são ferramentas muito utilizadas na seleção de modelos, mas não há muitos estudos que indiquem como os critérios de informação se desempenham na seleção dos efeitos fixos, efeitos aleatórios e da estrutura de covariância que compõe o erro aleatório. Diante disso, neste trabalho realizou-se um estudo de simulação para avaliar o desempenho dos critérios de informação AIC, BIC e KIC na seleção dos componentes do modelo misto, medido pela taxa TP (Taxa de verdadeiro positivo). De modo geral, os critérios de informação se desempenharam bem, ou seja, tiveram altos valores de taxa TP em situações em que o tamanho da amostra é maior. Na seleção de efeitos fixos e na seleção da estrutura de covariância, em quase todas as situações, o critério BIC teve um desempenho melhor em relação aos critérios AIC e KIC. Na seleção de efeitos aleatórios nenhum critério teve um bom desempenho, exceto na seleção de efeitos aleatórios em que considera a estrutura de simetria composta, situação em que BIC teve o melhor desempenho.The mixed model is commonly used in data of repeated measurements because of its flexibility to incorporate in the model the correlation existing between the observations measured in the same individual and the heterogeneity of variances of observations made over time. This model is composed of fixed effects, random effects and random error and with this in the selection of the mixed model it is often necessary to select the best components of the mixed model in such a way that it represents the data well. Information criteria are tools widely used in model selection, but there are not many studies that indicate how information criteria play out in the selection of fixed effects, random effects, and the covariance structure that makes up the random error. In this work, a simulation study was performed to evaluate the performance of the AIC, BIC and KIC information criteria in the selection of the components of the mixed model, measured by the TP (True positive Rate). In general, the information criteria performed well, that is, they had high TP rate in situations where the sample size is larger. In the selection of fixed effects and in the selection of the covariance structure, in almost all situations, the BIC criterion had a better performance in relation to the AIC and KIC criteria. In the selection of random effects no criterion had a good performance, except in the selection of Random effects in which it considers the compound symmetric structure, situation in which BIC had the best performance.
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Janovský, Martin. "Výběr vhodného ERP systému s pomocí metod vícekriteriálního rozhodování." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-165319.
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My thesis is intent on selection and recommendation of a suitable ERP system for the distribution company distributing tea and coffee products in the Czech market. To select a suitable system, I used methods of multi-criterion decision-making, concretely the ORESTE, WSA, TOPSIS and MAPPAC methods. In the theoretical part of my thesis, I describe the methods of multi-criterion decision-making and principles of utilization the ERP systems. The practical part of my thesis is divided in hard-selection and soft-selection. The aim of the hard-selection lies in reduction of the total number of ERP systems (upon available public information) which then shall be the subject to making the final selection. The soft-selection is then applied to the adjusted list of systems. Within the soft-selection, I included the applied procedure as well as reasons for selection of appropriate criterions since they essentially affect the calculation. At the end of my thesis, I show the procedure of implementation the ERP system.
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Selig, Katharina [Verfasser], Donna P. [Akademischer Betreuer] Ankerst, Pamela A. [Gutachter] Shaw, and Donna P. [Gutachter] Ankerst. "Bayesian information criterion approximations for model selection in multivariate logistic regression with application to electronic medical records / Katharina Selig ; Gutachter: Pamela A. Shaw, Donna P. Ankerst ; Betreuer: Donna P. Ankerst." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1211476367/34.
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Morgado, Maria de Fátima Romão. "Selecção de modelos em amostragem por distâncias." Master's thesis, Universidade de Évora, 2008. http://hdl.handle.net/10174/18339.
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A selecção do modelo que se ajuste adequadamente a um conjunto de dados é uma parte fulcral no processo da inferência estatística. O critério mais comum para seleccionar uma função de detectabilidade, que se ajuste a um conjunto de dados de distâncias, baseado na informação K-L, denomina-se critério de informação de Akaike (AIC). Para avaliar a performance da rotina da selecção de modelos implementada no programa DISTANCE, realizaram-se simulações Monte Carlo para gerar dados de duas funções densidade de probabilidade frequentemente usadas. Aplicando esta metodologia, observou-se um enviesamento substancial na selecção do modelo, sendo os estimadores dos parâmetros baseados no modelo seleccionado frequentemente enviesados. Utilizaram-se duas abordagens na estimação dos parâmetros: selecção de modelos tradicional e ponderação de modelos. Para ilustrar a metodologia da selecção de modelos usaram-se dados provenientes de um estudo controlado. ABSTRACT; The selection of a model that adequately fits a data set is an important part in the statistical inference process. The most commonly used criterion to select a detectability function that fits a distance sampling data set, is based on the K-L information, and it is known as the Akaike information criterion (AIC). ln order to evaluate the performance of the model selection routine implemented in software DISTANCE, we carried out Monte Carlo simulations generating data from two frequently used probability density functions. We found substantial model selection biases when using this methodology. We further observed that parameter estimators based on the selected model were often biased. Parameter estimation was conducted under two approaches: traditional model selection and model averaging. We used data from a controlled field experiment to illustrate the model selection methodology.
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Coelho, Fabiano Rodrigues. "Seleção de modelos multiníveis para dados de avaliação educacional." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/104/104131/tde-05122017-145244/.
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Quando um conjunto de dados possui uma estrutura hierárquica, uma possível abordagem são os modelos de regressão multiníveis, que se justifica pelo fato de haver uma porção significativa da variabilidade dos dados que pode ser explicada por níveis macro. Neste trabalho, desenvolvemos a seleção de modelos de regressão multinível aplicados a dados educacionais. Esta análise divide-se em duas partes: seleção de variáveis e seleção de modelos. Esta última subdivide-se em dois casos: modelagem clássica e modelagem bayesiana. Buscamos através de critérios como o Lasso, AIC, BIC, WAIC entre outros, encontrar quais são os fatores que influenciam no desempenho em matemática dos alunos do nono ano do ensino fundamental do estado de São Paulo. Também investigamos o funcionamento de cada um dos critérios de seleção de variáveis e de modelos. Foi possível concluir que, sob a abordagem frequentista, o critério de seleção de modelos BIC é o mais eficiente, já na abordagem bayesiana, o critérioWAIC apresentou melhores resultados. Utilizando o critério de seleção de variáveis Lasso para abordagem clássica, houve uma diminuição de 34% dos preditores do modelo. Por fim, identificamos que o desempenho em matemática dos estudantes do nono ano do ensino fundamental do estado de São Paulo é influenciado pelas seguintes covariáveis: grau de instrução da mãe, frequência de leitura de livros, tempo gasto com recreação em dia de aula, o fato de gostar de matemática, o desempenho em matemática global da escola, desempenho em língua portuguesa do aluno, dependência administrativa da escola, sexo, grau de instrução do pai, reprovações e distorção idade-série.When a dataset contains a hierarchical data structure, a possible approach is the multilevel regression modelling, which is justified by the significative amout of the data variability that can be explained by macro level processes. In this work, a selection of multilevel regression models for educational data is developed. This analysis is divided into two parts: variable selection and model selection. The latter is subdivided into two categories: classical and Bayesian modeling. Traditional criteria for model selection such as Lasso, AIC, BIC, and WAIC, among others are used in this study as an attempt to identify the factors influencing ninth grade students performance in Mathematics of elementary education in the State of São Paulo. Likewise, an investigation was conducted to evaluate the performance of each variable selection criteria and model selection methods applied to fitted models that will be mentioned throughout this work. It was possible to conclude that, under the frequentist approach, BIC is the most efficient, whereas under the bayesian approach, WAIC presented better results. Using Lasso under the frequentist approach, a decrease of 34% on the number of predictors was observed. Finally, we identified that the performance in Mathematics of students in the ninth year of elementary school in the state of São Paulo is most influenced by the following covariates: mothers educational level, frequency of book reading, time spent with recreation in classroom, the fact of liking Math, school global performance in Mathematics, performance in Portuguese, school administrative dependence, gender, fathers educational degree, failures and age-grade distortion.
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Akdemir, Deniz. "A Class of Multivariate Skew Distributions: Properties and Inferential Issues." Bowling Green, Ohio : Bowling Green State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1237574643.
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Havlů, Michal. "Algoritmus automatického výběru vhodného typu zařízení z databáze výměníků tepla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228730.
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Thesis is devoted to development of an database algorithm for selection (or necking selection) of suitable type of heat exchanger for given industrial application. Database creates a part of multipurpose calculation system containing three individual modules: (i) module for selection (or necking selection) of type of heat exchanger for given application, (ii) module for thermal-hydraulic design or rating of heat exchanger, (iii) module for calculation of investments and operating cost. Thesis describes details of method for selection of suitable heat exchanger type for given application and presents and discuss individual criteria for selection process which influence values in tables of priorites for given equipment. These tables are unavoible part of selection algorithm. Details of software application of selection algorithm are also presented in the thesis. Description of behaviour of individual types of heat exchanger creates important part of thesis. Practical application of developed selection algorithm is demonstrated on several industrial examples.
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Nualnim, Nuanyong, and Chayanut Phuaksawat. "Customer’s selection criteria when booking yacht online." Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-9841.
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Problem: Online yacht booking market is now very competitive market. There are many
yacht online companies in the market. Therefore, it is critical for yacht online
companies to understand customers’ needs and to know what the selection
criteria are that customers use to book yacht online. As rental yacht sales agents
are mostly virtual companies, which mainly use Internet to reach target
customers and conduct most of the purchase process. Therefore, one question
that need to be researched is how important is the website for the rental yacht
sales agent when it comes to getting new customers and keeping the old ones?
Purpose: The purpose of the study is to find out what the selection criteria which
customers use to evaluate when booking yacht online are.
Method: This study is primarily based on qualitative research by using in-depth interview
method. Customer decision making process is applied in order to suit with the
topic. The data collection came from two sources, primary and secondary data.
Conclusion: The important selection criteria for new customers are websites containing
necessary information which mentioned by the interviewees during the
interview, word of mouth of the company and services from the company and its
sale staff. These three selection criteria have huge effect on new customers in
order to book yacht online. For the experienced customers, there are two selection
criteria which are considered as the most important criteria which are services
from the company and its sale staff and website containing necessary information.
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Caglar, Musa. "Multiple Criteria Project Selection Problems." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610945/index.pdf.
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In this study, we propose two biobjective mathematical models based on
PROMETHEE V method for project selection problems. We develop an interactive
approach (ib-PROMETHEE V) including data mining techniques to solve the first
proposed mathematical model. For the second model, we propose NSGA-II with
constraint handling method. We also develop a Preference Based Interactive
Multiobjective Genetic Algorithm (IMGA) to solve the second proposed
mathematical model. We test the performance of NSGA-II with constraint handling
method and IMGA on randomly generated test problems.
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Reintjes, Eric. "COTS selection criteria in government programs." Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01262010-020208/.
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Deijk, Manuel. "Behavioral Selection Criteria And Portfolio Performance." St. Gallen, 2006. http://www.biblio.unisg.ch/org/biblio/edoc.nsf/wwwDisplayIdentifier/00642330001/$FILE/00642330001.pdf.
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Andersson, Håkan. "Relativa betyg : några empiriska studier och en teoretisk genomgång i ett historiskt perspektiv." Doctoral thesis, Umeå universitet, Pedagogiska institutionen, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-16593.
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Denna avhandling, som i huvudsak är resultatet av ett projekt finansierat av Skolöverstyrelsen, består av fem delstudier (I-V) utförda under åren 1977-1991 samt en sammanfattande analysdel (VI). Avhandlingens syfte är att studera det unika svenska relativa betygssystemet, som infördes på försök i folkskolan i början av 1940-talet för att senare permanentas och även införas i enhets- och grundskolan samt slutligen även i gymnasiet. Det relativa betygssystemet beskrivs enligt följande indelning: framväxt och avveckling (V), funktioner (I), effekter och sidoeffekter (III) samt användning och behov (II och IV). I de empiriska studierna har elever, lärare, arbetsgivare och arbetstagare fått ge sina synpunkter på de relativa betygen. I delstudie V analyseras utvecklingen av det relativa betygssystemet med hjälp av offentliga utredningar, remissvar från elev-, lärar-, aibetsgivar- och arbetstagarorganisationer samt också via riksdagstryck.De relativa betygen beskrivs som starkt knutna till urvalet till högre studier och som ett försök att tillskapa ett urvalsinstrument med möjlighet till jämförbarhet och större rättvisa. Betygen har visat sig spela liten roll vid urvalet till olika arbeten. Betygen fyller en "körkortsfunktion" genom att ange inriktning och linje. I övrigt speglar betygen i huvudsak förmåga att tillgodogöra sig teoretiskt stoff. Vid urvalet till olika arbeten beskrivs en utveckling från formella till informella meriter i form av vissa personlighetsegenskaper, t ex samarbetsförmåga, flexibilitet och utåtriktad läggning. Arbetslivserfarenhet, referenser och personlighetsegenskaper betyder mer vid anställningar än skolbetygen.I avhandlingen anges såväl mättekniska, informationstekniska som socialpsykologiska förklaringar till att det relativa betygssystemet är på väg att avvecklas. Betänkligheter riktas mot ett eventuellt införande av målrelaterade betyg p g a styrningsriskerna för elever och lärare, samt också mot riskerna för en ökad kontroll och ett ökat beroende av avnämarna. I avhandlingen noteras skillnader mellan praktiska och teoretiska linjer när det gäller synen på betyg. Som tänkbara förklaringar anges användningen och behovet av betyg liksom också närheten och kopplingen till näringslivet. Betygens officiella funktioner som informations-, motivations- och urvalsinstrument har gradvis minskat. Tidigare har frågor om styrning och kontroll kommit i bakgrunden i förhållande till de officiella funktionerna. Om målrelaterade betyg införs och om betygens roll som urvalsinstrument försvinner, torde betygens styrnings- och kontrollfunktioner behöva diskuteras och motiveringar till att över huvud taget ha kvar betyg i skolan lyftas fram.This dissertation, which is mainly the result of a project financed by the National Board of Education, consists of five substudies (I-V) carried out between 1977 and 1991, and a summary analysis (VI). The aim of the dissertation is to study group-referenced marks which are unique for Sweden. In the 1940s they were introduced on trial into elementary school, where they were later permanent, and they were also introduced into comprehensive school, nine-year compulsory school and finally also into upper secondary school. The description of group-referenced marks is divided into the following substudies: development and phase-out (V), functions (I), effects and side-effects (III), and use and requirements (II and IV). In the empirical studies, students, teachers, employers and employees have been asked to give their opinions of group-referenced marks. Substudy V analyses the development of group-referenced marks through official reports, through reactions to these reports from student, teacher, employers' and employees' organizations, and also through official parliamentary publications.Group-referenced marks are described as closely connected with the selection to higher education and as an attempt to construct an instrument of selection offering possibilities of comparability and greater justice. Marks have proved to be of little consequence for employment. They function as a "driving licence" by indicating direction and course programme. Marks reflect, above all, the ability to assimilate theoretical subject-matter. The selection to various employments manifests a development from formal to informal merits in the form of certain qualities, e. g. the ability to co-operate, flexibility and extrovert behaviour. Work experience, references and personal qualities are more important than marks for employmentThe dissertation indicates measurement technological, information technological and socio-psychological explanations of withdrawing group-referenced marks. The dissertation also expresses apprehensions about the potential introduction of criterion-referenced marks owing to the steering effects for pupils and teachers, as well as about the risks of increasing control and dependence on potential employers. Differences between practical and theoretical course programmes regarding attitudes to marks can also be observed. These differences can perhaps be explained by the use and needs of marks as well as by the nearness and connection to industry and commerce. The importance of the official functions of marks as information, motivation and selection instruments has gradually been reduced. Problems of steering and control used to be subordinate to the official functions. If criterion-referenced marks are introduced and if marks lose their selection function, the steering and control functions of marks should be discussed and the motives for preserving marks in school should be presented.
digitalisering@umu
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Vismara, Edgar de Souza. "Mensuração da biomassa e construção de modelos para construção de equações de biomassa." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-18052009-155116/.
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O interesse pela quantificação da biomassa florestal vem crescendo muito nos últimos anos, sendo este crescimento relacionado diretamente ao potencial que as florestas tem em acumular carbono atmosférico na sua biomassa. A biomassa florestal pode ser acessada diretamente, por meio de inventário, ou através de modelos empíricos de predição. A construção de modelos de predição de biomassa envolve a mensuração das variáveis e o ajuste e seleção de modelos estatísticos. A partir de uma amostra destrutiva de de 200 indivíduos de dez essências florestais distintas advindos da região de Linhares, ES., foram construídos modelos de predição empíricos de biomassa aérea visando futuro uso em projetos de reflorestamento. O processo de construção dos modelos consistiu de uma análise das técnicas de obtenção dos dados e de ajuste dos modelos, bem como de uma análise dos processos de seleção destes a partir do critério de Informação de Akaike (AIC). No processo de obtenção dos dados foram testadas a técnica volumétrica e a técnica gravimétrica, a partir da coleta de cinco discos de madeira por árvore, em posições distintas no lenho. Na técnica gravimétrica, estudou-se diferentes técnicas de composição do teor de umidade dos discos para determinação da biomassa, concluindo-se como a melhor a que utiliza a média aritmética dos discos da base, meio e topo. Na técnica volumétrica, estudou-se diferentes técnicas de composição da densidade do tronco com base nas densidades básicas dos discos, concluindo-se que em termos de densidade do tronco, a média aritmética das densidades básicas dos cinco discos se mostrou como melhor técnica. Entretanto, quando se multiplica a densidade do tronco pelo volume deste para obtenção da biomassa, a utilização da densidade básica do disco do meio se mostrou superior a todas as técnicas. A utilização de uma densidade básica média da espécie para determinação da biomassa, via técnica volumétrica, se apresentou como uma abordagem inferior a qualquer técnica que utiliza informação da densidade do tronco das árvores individualmente. Por fim, sete modelos de predição de biomassa aérea de árvores considerando seus diferentes compartimentos foram ajustados, a partir das funções de Spurr e Schumacher-Hall, com e sem a inclusão da altura como variável preditora. Destes modelos, quatro eram gaussianos e três eram lognormais. Estes mesmos sete modelos foram ajustados incluindo a medida de penetração como variável preditora, totalizando quatorze modelos testados. O modelo de Schumacher-Hall se mostrou, de maneira geral, superior ao modelo de Spurr. A altura só se mostrou efetiva na explicação da biomassa das árvores quando em conjunto com a medida de penetração. Os modelos selecionados foram do grupo que incluíram a medida de penetração no lenho como variável preditora e , exceto o modelo de predição da biomassa de folhas, todos se mostraram adequados para aplicação na predição da biomassa aérea em áreas de reflorestamento.Forest biomass measurement implies a destructive procedure, thus forest inventories and biomass surveys apply indirect procedure for the determination of biomass of the different components of the forest (wood, branches, leaves, roots, etc.). The usual approch consists in taking a destructive sample for the measurment of trees attributes and an empirical relationship is established between the biomass and other attributes that can be directly measured on standing trees, e.g., stem diameter and tree height. The biomass determination of felled trees can be achived by two techniques: the gravimetric technique, that weights the components in the field and take a sample for the determination of water content in the laboratory; and the volumetric technique, that determines the volume of the component in the field and take a sample for the determination of the wood specific gravity (wood basic density) in the laboratory. The gravimetric technique applies to all components of the trees, while the volumetric technique is usually restricted to the stem and large branches. In this study, these two techniques are studied in a sample fo 200 trees of 10 different species from the region of Linhares, ES. In each tree, 5 cross-sections of the stem were taken to investigate the best procedure for the determination of water content in gravimetric technique and for determination of the wood specific gravity in the volumetric technique. Also, Akaike Information Criterion (AIC) was used to compare different statistical models for the prediction o tree biomass. For the stem water content determination, the best procedure as the aritmetic mean of the water content from the cross-sections in the base, middle and top of the stem. In the determination of wood specific gravity, the best procedure was the aritmetic mean of all five cross-sections discs of the stem, however, for the determination of the biomass, i.e., the product of stem volume and wood specific gravity, the best procedure was the use of the middle stem cross-section disc wood specific gravity. The use of an average wood specific gravity by species showed worse results than any procedure that used information of wood specific gravity at individual tree level. Seven models, as variations of Spurr and Schumacher-Hall volume equation models, were tested for the different tree components: wood (stem and large branches), little branches, leaves and total biomass. In general, Schumacher-Hall models were better than Spurr based models, and models that included only diameter (DBH) information performed better than models with diameter and height measurements. When a measure of penetration in the wood, as a surrogate of wood density, was added to the models, the models with the three variables: diameter, height and penetration, became the best models.
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Nålsund, Roar. "Railway Ballast Characteristics, Selection Criteria and Performance." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-27348.
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This work is a comprehensive investigation to find to what extent simple laboratory tests e.g. Los Angeles abrasion and micro-Deval might be suitable for predicting real railway ballast performance with respect to deformation and degradation. A number of tests to measure essential properties of ballast aggregate have been performed in addition to advanced material testing. Large cyclic triaxial loading test and full scale railway track model test were employed to simulate the effects of train loading and tamping, and to study settlement, stiffness and degradation of a range of ballast materials. The testing programme included both wet and dry testing conditions. All the rock types tested were mainly composed of combinations of principal rock-forming silicate minerals. They represent all together a wide variety of igneous, metamorphic and consolidated/metamorphosed sedimentary rocks mainly fine to very fine grained. Mechanical properties Change in the ballast grading proved to affect the ballast breakage development over time. However, the abrasion property expressed by the micro-Deval value did not show any association with the degradation of ballast under repeated load testing. Simulation of repeated tamping seemed to be the main source of ballast breakage. Most rocks showed high frost resistance after long term impact, but samples with high content of amphibole were less frost resistant. The rocks’ mechanical strength in terms of the Los Angeles abrasion or micro-Deval value did not show any correlation with either the amount of microcracks or the rocks’ average mineral grain size. A new method to measure the amount of microcracks based on luminescence measurements was developed. It is suggested that micro-cracks represent open channels for water to penetrate into the aggregate, which was confirmed by good correlation between water absorption and the amount of micro-cracks. Moisture had generally a negative effect on rocks’ mechanical strength according to Los Angeles abrasion and Point Load strength results. On the other hand, dry and wet triaxial tests with cyclic loadings did not confirm this effect. Neither did mineral grain size distribution show any correlation with mechanical strength, but the range of coefficient of conformity (Cu = D60/D10) was probably too narrow to obtain a reliable conclusion. A new method to quantify the mineral grain size distribution was developed under these test series. Functional properties Both resilient modulus of the ballast layer and the stiffness of the track were governed by the materials’ grading curve and specific density. A possible relation between the amount of microcracks in the aggregate and resilient modulus as well as ballast breakage is suggested. The permanent vertical strain during repeated load testing was affected by both the micro-Deval value, the grading curve of the ballast and the aggregate’s content of soft minerals. Improvements of test methods The Los Angeles abrasion test distinguished clearly between the superior quality material and the very poor material. The Los Angeles abrasion value is, however, a poor parameter to indicate how the intermediate material will behave in service regarding ballast breakage. This study proposes to improve the ranking of ballast materials by introducing two additional methods. One which is able to measure some rocks’ ability to recover mechanical strength after repeated crushing, and one which measures the production of fines (0/0.125 mm) during crushing. Saturation of ballast material before micro-Deval testing did not have any significant effect on degradation. Neither did the use of 1 % sodium-chloride solution have any effect.
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Wågström, Greta, and Gustav Meisner. "Innovation Management : Evaluation Criteria for Idea Selection." Thesis, KTH, Industriell ekonomi och organisation (Inst.), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-252750.
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Innovation outside the company’s core business is essential for any company in a fast-changing environment. Companies that want to engage in strategic innovation in order to embrace emerging opportunities need ways of managing the innovation process. There is currently limited research on how to select among and evaluate innovation proposals for emerging opportunities in the context of intrapreneurship. This master thesis investigates how an incumbent high-tech company that promote intrapreneurship uses criteria in the selection process of innovation proposals. The study conducts an embedded single-case study of the case company, referred to as Company A, by collecting qualitative data through archival documents and 19 semi-structured interviews. The study uses Christensen’s theory of disruptive innovation to analyse the results. Findings show that an incumbent high-tech company uses a set of criteria that is a mix of the previous findings in the context of new product development and external investors. The criteria utilized in the selection process are within the dimensions market and value, product and technology, operations and financials, corporate alignment, and team. The conducted interviews exposed that personal considerations constitute additional informal criteria for the evaluators, and much emphasis is put on the intrapreneur’s characteristics and presentation. Findings from the interviews suggest that criteria should be utilized less strict in the beginning of the process, which is supported by previous researchers. Criteria also contribute with transparency to the innovation process and can be used as guidelines for the innovator. Christensen’s theory contradicts the use of the criteria market size, corporate alignment and to validate the innovation with a customer because of the nature of emerging markets and technologies.Innovation utanför företagets kärnverksamhet är viktigt för alla företag på en snabbt föränderlig marknad. Företag som vill satsa på strategisk innovation för att kunna ta tillvara på nya möjligheter behöver metoder för att kunna hantera innovationsprocessen. Detta examensarbete undersöker hur ett etablerat högteknologiskt företag som främjar intraprenörskap använder kriterier i urvalsprocessen att välja mellan olika innovationsförslag. Studien genomför en fallstudie genom att studera ett bolag, benämnt företag A, och samlar in kvalitativa data genom arkivdokument och 19 semistrukturerade intervjuer. Studien använder Christensens teori om disruptiv innovation för att analysera resultaten. Resultaten visar att det studerade högteknologiska företaget använder ett antal kriterier som stöds av tidigare forskares resultat inom området produktutveckling och externa investerare. Kriterierna som identifieras i studien är inom dimensionerna marknad och värdeskapande, produkt och teknik, företagsverksamhet och ekonomi, hur väl innovationen passar företaget och team. Intervjuerna avslöjade att personliga överväganden utgör ytterligare informella kriterier för de som utvärderar, som lägger stor vikt på intraprenörens egenskaper och presentation. Resultaten tyder på att kriterierna bör användas mindre strikt i början av processen, vilket stöds av tidigare forskning. Kriterier bidrar också till insyn i innovationsprocessen och kan användas som riktlinjer för innovatören. Christensens teori stödjer inte användningen av kriterierna marknadsstorlek, hur väl innovationen passar företaget och att verifiera innovationen med en kund på grund av osäkerhet kring framväxande marknader och nya teknologier.
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Sirisalee, Pasu. "Multi-criteria material selection in engineering design." Thesis, University of Cambridge, 2005. https://www.repository.cam.ac.uk/handle/1810/251967.
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