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  • 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.
31

Applications of Contact Length Models in Grinding Processes

Qi, Hong Sheng, Mills, B., Xu, X.P. January 2009 (has links)
yes / The nature of the contact behaviour between a grinding wheel and a workpiece in the grinding process has a great effect on the grinding temperature and the occurrence of thermal induced damage on the ground workpiece. It is found that the measured contact length le in grinding is considerably longer than the geometric contact length lg and the contact length due to wheel-workpiece deflection lf. The orthogonal relationship among the contact lengths, i.e. lc2 = (Rrlf)2 + lg2, reveals how the grinding force and grinding depth of cut affect the overall contact length between a grinding wheel and a workpiece in grinding processes. To make the orthogonal contact length model easy to use, attempts on modification of the model are carried out in the present study, in which the input variable of the model, Fn’, is replaced by a well-established empirical formula and specific grinding power. By applying the modified model in this paper, an analysis on the contributions of the individual factors, i.e. the wheel/workpiece deformation and the grinding depth of cut, on the overall grinding contact length is conducted under a wide range of grinding applications, i.e. from precise/shallow grinding to deep/creep-feed grinding. Finally, using a case study, the criterion of using geometric contact length lg to represent the real contact length lc, in terms of convenience versus accuracy, is discussed.
32

Effects of criterion bias on perimetric sensitivity and response variability in glaucoma

Rubinstein, N.J., Turpin, A., Denniss, Jonathan, McKendrick, A.M. 15 February 2021 (has links)
Yes / The purpose of this study was to isolate and quantify the effects of observer response criterion on perimetric sensitivity, response variability, and maximum response probability. Twelve people with glaucoma were tested at three locations in the visual field (age = 47-77 years, mean deviation = -0.61 to -14.54 dB, test location Humphrey field analyzer [HFA] sensitivities = 1 to 30 dB). Frequency of seeing (FoS) curves were measured using a method of constant stimuli with two response paradigms: a "yes-no" paradigm similar to static automated perimetry and a criterion-free two interval forced choice (2IFC) paradigm. Comparison measures of sensitivity, maximum response probability, and response variability were derived from the fitted FoS curves. Sensitivity differences between the tasks varied widely (range = -11.3 dB to 21.6 dB) and did not correlate with visual field sensitivity nor whether the visual field location was in an area of steep sensitivity gradient within the visual field. Due to the wide variation in differences between the methods, there was no significant difference in mean sensitivity between the 2IFC task relative to the yes-no task, but a trend for higher sensitivity (mean = 1.9 dB, SD = 6.0 dB, P = 0.11). Response variability and maximum response probability did not differ between the tasks (P > 0.99 and 0.95, respectively). Perimetric sensitivity estimates are demonstrably altered by observer response criterion but the effect varies widely and unpredictably, even within a single test. Response bias should be considered a factor in perimetric test variability and when comparing sensitivities to nonperimetric data. The effect of response criterion on perimetric response variability varies widely and unpredictably, even within a single test. / Supported by ARC LP130100055; ARC LP150100815 (AT and AMM), College of Optometrists Research Fellowship (JD).
33

A Comparison of Two Criterion-Referenced Item-Selection Techniques Utilizing Simulated Data with Item Pools that Vary in Degrees of Item Difficulty

Davis, Robbie G. 05 1900 (has links)
The problem of this study was to examine the equivalency of two different types of criterion-referenced item-selection techniques on simulated data as item pools varied in degrees of item difficulty. A pretest-posttest design was employed in which pass-fail scores were randomly generated for item pools of twenty-five items. From the item pools, the two techniques determined which items were to be used to make up twelve-item criterion-referenced tests. The twenty-five items also were rank ordered according to the discrimination power of the two techniques.
34

A Comparison of Three Item Selection Methods in Criterion-Referenced Tests

Lin, Hui-Fen 08 1900 (has links)
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.
35

The Characteristics and Properties of the Threshold and Squared-Error Criterion-Referenced Agreement Indices

Dutschke, Cynthia F. (Cynthia Fleming) 05 1900 (has links)
Educators who use criterion-referenced measurement to ascertain the current level of performance of an examinee in order that the examinee may be classified as either a master or a nonmaster need to know the accuracy and consistency of their decisions regarding assignment of mastery states. This study examined the sampling distribution characteristics of two reliability indices that use the squared-error agreement function: Livingston's k^2(X,Tx) and Brennan and Kane's M(C). The sampling distribution characteristics of five indices that use the threshold agreement function were also examined: Subkoviak's Pc. Huynh's p and k. and Swaminathan's p and k. These seven methods of calculating reliability were also compared under varying conditions of sample size, test length, and criterion or cutoff score. Computer-generated data provided randomly parallel test forms for N = 2000 cases. From this, 1000 samples were drawn, with replacement, and each of the seven reliability indices was calculated. Descriptive statistics were collected for each sample set and examined for distribution characteristics. In addition, the mean value for each index was compared to the population parameter value of consistent mastery/nonmastery classifications. The results indicated that the sampling distribution characteristics of all seven reliability indices approach normal characteristics with increased sample size. The results also indicated that Huynh's p was the most accurate estimate of the population parameter, with the smallest degree of negative bias. Swaminathan's p was the next best estimate of the population parameter, but it has the disadvantage of requiring two test administrations, while Huynh's p index only requires one administration.
36

Odlehlá pozorování / Outliers

Kudrnáč, Vojtěch January 2015 (has links)
This paper concerns itself with the methods of identifying outliers in an otherwise normally distributed data set. Several significant tests and criteria designed for this purpose are described here, Peirce's criterion, Chauvenet's criterion, Grubbs' test, Dixon's test and Cochran's test. Deriving of the tests and criteria is indicated and finally the results of the use of the test and criteria on simulated data with normal distribution and inserted outlier are looked into. Codes in programming language R with the implementation of these test and criteria using existing functions are included. Powered by TCPDF (www.tcpdf.org)
37

Infanticídio / Infanticide

Argachoff, Mauro 25 April 2011 (has links)
Tipificado de forma autônoma pela nossa legislação, o delito de infanticídio, previsto no artigo 123 do Código Penal, trata da conduta da mãe que tira a vida do próprio filho durante ou logo após o parto. Historicamente cercado de dúvidas e pontos de conflito, a conduta infanticida passou por extremos, indo da punição absolutamente desumana à total benevolência para com o violador da norma. Analisada a figura típica do infanticídio, percebe-se uma modalidade especial do crime de homicídio que o legislador preferiu apenar mais brandamente. Em um primeiro momento, foi levado em consideração para justificar tal abrandamento o critério psicológico, baseado na honra da mãe. Posteriormente, tal critério foi substituído pelo fisiopsicológico, onde o estado puerperal passou a ser a elementar do tipo. Em conjunto com o estado puerperal, o lapso temporal em que a conduta deve ser praticada, durante ou logo após o parto, fazem do infanticídio um dos delitos que mais geram dúvidas dentro no ordenamento jurídico vigente. Considerada a genitora sujeito ativo do delito, o estado puerperal como elementar do tipo suscita questionamentos a respeito da prática do crime em concurso de agentes. Igualmente, a não previsão da modalidade culposa ao tipo caracteriza uma lacuna geradora de conflitos doutrinários em caso da morte do nascente ou neonato por imprudência ou negligência da mãe. Juntamente com toda problemática que o tipo apresenta, o julgamento do delito pelo Tribunal do Júri, com as alterações legislativas recentemente sofridas por esse instituto, faz com que o infanticídio seja, mais uma vez, objeto de dúvidas com relação ao modo como a quesitação deve ser apresentada. Útil ao estudo do tema, uma análise do crime, frente às legislações dos demais países da América Latina e alguns países da Europa, darão um quadro geral de como o delito é tratado fora de nossas fronteiras. Por fim, espera-se contribuir para que se forme uma opinião sobre a necessidade ou não da manutenção do tipo, de forma autônoma, em nosso ordenamento jurídico. / Typified autonomously by our legislation, the crime of infanticide under the article 123 of the Penal Code, deals with the behaviour of the mother who takes the life of her own son during the child-birth or soon after it. Historically surrounded by doubts and conflicts, the infanticidal conduct has gone through extremes, from totally unhumane punishment to total benevolence for the violator of the law. After analyzing the typical figure of infanticide, we can notice a special genre of homicide that the legislator chose to punish more softly. At first it was considered the psychological criterion to justify such mitigation, based on the mothers honour. After that, such criterion was replaced by the physiopsychological, where the puerperal state became the base of the type. Together with the puerperal state, the time lag in which the conduct must be practised, during the child-birth or soon after that, turns the infanticide into one of the crimes that most generates doubts inside the actual legal system. As the genitor is considered the active subject of the crime, the puerperal state as the base of the type evokes questioning about the practice of the crime in competition of agents. In the same way, the non prevision of the fault mode to the type caracterizes a gap generator of doctrinaire conflicts in case of the death of the new born because of the mothers imprudence or neglection. Together with all the set of problems that the type introduces, the judgement of the delict by the Court of Justice, with the recent legislative changes occurred in this institute, turns the infanticide, once more, the object of doubts in respect to the way the inquiry is presented. Useful for the study of the subject, the analysis of the crime facing the legislation of the other Latin American countries and some European countries will show a general view of how the delict is dealt with outside our borders. Finally, it is expected to contribute in order to form an opinion about the necessity or no necessity of the maintenance of the type autonomously in our legal system.
38

KLIC作為傾向分數配對平衡診斷之可行性探討 / Using Kullback-Leibler Information Criterion on balancing diagnostics for baseline covariates between treatment groups in propensity-score matched samples

李珮嘉, Li, Pei Chia Unknown Date (has links)
觀察性研究資料中,透過傾向分數的使用,可以使基準變數在實驗與對照兩組間達到某種程度的平衡,並可視同為一隨機試驗,進而進行有效的統計推論。文獻中有關平衡與否的診斷,大多聚焦於平均數與變異數的比較。本文中我們提出使用KLIC(Kullback-Leibler Information Criterion)及KS(Kolmogorov and Simonov)兩種比較分配函數差異的統計量,作為另一種平衡診斷工具的構想,並針對其可行性進行探討與評比。此外,數據顯示KLIC及KS與透過傾向分數配對的成功比例呈現負相關。由於配對成功比例過低將導致後續統計推論結果的侷限性,因此本文也就KLIC及KS作為是否進行配對的一個先行指標之可行性作探討。模擬結果顯示,二者的答案均是肯定的。 / In observational studies, propensity scores are frequently used as tools to balance the distribution of baseline covariates between treated and untreated groups to some extent so that the data could be treated as if they were from a randomized controlled trial (RCT) and causal inferences could thus be made. In the past, balance or not was usually diagnosed in terms of the means and/or the variances. In this study, we proposed using either Kullback-Leibler Information Criterion (KLIC) or Kolmogorov and Simonov (KS) statistic as a diagnostic measure, and evaluated its feasibility. In addition, since low propensity score matching rate decreases the power of the statistical inference and a pilot study showed that the matching rate was negatively correlated with KLIC and KS; thus, we also discussed the possibilities of using KLIC and KS to be pre-indices before implementing propensity score matching. Both considerations appear to be positive through our simulation study.
39

Les créanciers postérieurs d'une procédure collective. : Etude des interactions entre le droit des entreprises en difficulté et le droit des garanties de paiement / Posterior creditors of insolvency procedure : Analyse of interactions between insolvency law and guarantees payment

Boustani, Diane 06 December 2013 (has links)
Avec la loi du 26 juillet 2005, le sort des créanciers postérieurs a subi de profondes modifications. Répartis en deux catégories distinctes par l’effet d’un critère téléologique, leur traitement par la procédure collective n’est plus identique. Les créanciers postérieurs non éligibles au traitement préférentiel subissent les règles contraignantes de la procédure collective, tandis que seuls les créanciers postérieurs dits « méritants » bénéficient d’un paiement à l’échéance et d’un paiement par privilège. Toutefois, par de nombreux aspects, les créanciers postérieurs élus sont également confrontés à la rigueur de la procédure, altérant leurs possibilités réelles de paiement. La situation des créanciers postérieurs, dans leur ensemble, contraste avec celle conférée au débiteur qui n’a plus à craindre l’ouverture d’une procédure collective, celle-ci étant devenue une technique de gestion mise à sa disposition et particulièrement protectrice de ses droits. Dès lors, le salut des créanciers postérieurs semble se situer à l’extérieur de la procédure. Instrumentalisé par le droit des entreprises en difficulté, le droit des garanties de paiement, droit par nature égoïste, leur offre de nombreuses opportunités d’échapper à l’emprise de la procédure. Si le sujet impose une approche technique de la situation des créanciers postérieurs, il a surtout pour ambition de s’inscrire dans une perspective d’ensemble afin de mettre en lumière les nombreuses contradictions qui irriguent la matière. / With the law of July 26th, 2005, the situation of posterior creditors has changed. Divided into two distinct categories by the effect of a teleological criterion, their treatment by insolvency procedures are not identical. Posterior creditors who are not eligible for the preferential treatment suffer the binding rules of insolvency law, while only posterior creditors called "deserving" receive a payment due date and a privilege. However, in several aspects, these posterior creditors also face the rigor of the procedure, altering their chances to obtain payment. The situation of posterior creditors contrast with the situation conferred to the debtor. The protection of posterior creditors appears to be outside of the procedure. Instrumentalized by the insolvency law, payment guarantees offer many opportunities to escape the influence of the procedure. If the subject requires a technical approach of the situation of posterior creditors, he supposes to make a global study in order to show the many contradictions which irrigate the discipline.
40

Infanticídio / Infanticide

Mauro Argachoff 25 April 2011 (has links)
Tipificado de forma autônoma pela nossa legislação, o delito de infanticídio, previsto no artigo 123 do Código Penal, trata da conduta da mãe que tira a vida do próprio filho durante ou logo após o parto. Historicamente cercado de dúvidas e pontos de conflito, a conduta infanticida passou por extremos, indo da punição absolutamente desumana à total benevolência para com o violador da norma. Analisada a figura típica do infanticídio, percebe-se uma modalidade especial do crime de homicídio que o legislador preferiu apenar mais brandamente. Em um primeiro momento, foi levado em consideração para justificar tal abrandamento o critério psicológico, baseado na honra da mãe. Posteriormente, tal critério foi substituído pelo fisiopsicológico, onde o estado puerperal passou a ser a elementar do tipo. Em conjunto com o estado puerperal, o lapso temporal em que a conduta deve ser praticada, durante ou logo após o parto, fazem do infanticídio um dos delitos que mais geram dúvidas dentro no ordenamento jurídico vigente. Considerada a genitora sujeito ativo do delito, o estado puerperal como elementar do tipo suscita questionamentos a respeito da prática do crime em concurso de agentes. Igualmente, a não previsão da modalidade culposa ao tipo caracteriza uma lacuna geradora de conflitos doutrinários em caso da morte do nascente ou neonato por imprudência ou negligência da mãe. Juntamente com toda problemática que o tipo apresenta, o julgamento do delito pelo Tribunal do Júri, com as alterações legislativas recentemente sofridas por esse instituto, faz com que o infanticídio seja, mais uma vez, objeto de dúvidas com relação ao modo como a quesitação deve ser apresentada. Útil ao estudo do tema, uma análise do crime, frente às legislações dos demais países da América Latina e alguns países da Europa, darão um quadro geral de como o delito é tratado fora de nossas fronteiras. Por fim, espera-se contribuir para que se forme uma opinião sobre a necessidade ou não da manutenção do tipo, de forma autônoma, em nosso ordenamento jurídico. / Typified autonomously by our legislation, the crime of infanticide under the article 123 of the Penal Code, deals with the behaviour of the mother who takes the life of her own son during the child-birth or soon after it. Historically surrounded by doubts and conflicts, the infanticidal conduct has gone through extremes, from totally unhumane punishment to total benevolence for the violator of the law. After analyzing the typical figure of infanticide, we can notice a special genre of homicide that the legislator chose to punish more softly. At first it was considered the psychological criterion to justify such mitigation, based on the mothers honour. After that, such criterion was replaced by the physiopsychological, where the puerperal state became the base of the type. Together with the puerperal state, the time lag in which the conduct must be practised, during the child-birth or soon after that, turns the infanticide into one of the crimes that most generates doubts inside the actual legal system. As the genitor is considered the active subject of the crime, the puerperal state as the base of the type evokes questioning about the practice of the crime in competition of agents. In the same way, the non prevision of the fault mode to the type caracterizes a gap generator of doctrinaire conflicts in case of the death of the new born because of the mothers imprudence or neglection. Together with all the set of problems that the type introduces, the judgement of the delict by the Court of Justice, with the recent legislative changes occurred in this institute, turns the infanticide, once more, the object of doubts in respect to the way the inquiry is presented. Useful for the study of the subject, the analysis of the crime facing the legislation of the other Latin American countries and some European countries will show a general view of how the delict is dealt with outside our borders. Finally, it is expected to contribute in order to form an opinion about the necessity or no necessity of the maintenance of the type autonomously in our legal system.

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