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1.
Outlier detection by means of robust regression estimators for use in engineering science 总被引：1，自引：0，他引：1
This study compares the ability of different robust regression estimators to detect and classify outliers. Well-known estimators with high breakdown points were compared using simulated data. Mean success rates （MSR） were computed and used as comparison criteria. The results showed that the least median of squares （LMS） and least trimmed squares （LTS） were the most successful methods for data that included leverage points, masking and swamping effects or critical and concentrated outliers. We recommend using LMS and LTS as diagnostic tools to classify outliers, because they remain robust even when applied to models that are heavily contaminated or that have a complicated structure of outliers. 相似文献
2.
Most studies of persistence behavior use path analysis or ordinary least squares regression to estimate unknown coefficients. However, estimates produced by these techniques are biased if selectivity bias contaminates choices made by individuals in the data sample. We explain this problem, argue that it is present in data samples used in persistence studies, and discuss an alternative estimation technique that controls for it. The methodology and the differences in the interpretation of coefficient estimates are illustrated with a data sample of individual students at a single university. 相似文献
3.
The least means squares (LMS) adaptive filter algorithm was used in active suspension system. By adjusting the weight of adaptive filter, the minimum quadratic performance index was obtained. For two-degree-of-freedom vehicle suspension model, LMS adaptive controller was designed. The acceleration of the sprung mass,the dynamic tyre load between wheels and road,and the dynamic deflection between sprung mass and unsprung mass were determined as the evaluation targets of suspension performance. For LMS adaptive control suspension, compared with passive suspension, acceleration power spectral density of sprung mass acceleration under the road input model decreased 8-10 times in high frequency resonance band or low frequency resonance band. The simulation results show that LMS adaptive control is simple and remarkably effective. It further proves that the active control suspension system can improve both the riding comfort and handling safety in various operation conditions, and the method is fit for the active control of the suspension system. 相似文献
4.
Neal Dreamson Gary Thomas Anita Lee Hong Soyoung Kim 《Technology, Pedagogy and Education》2013,22(4):431-444
ABSTRACTLearning management systems (LMS) have been utilised for enhancing the quality of learning and teaching in higher education, yet the cultural needs of Indigenous students are rarely considered. The study reimagines culturally inclusive learning in an LMS by critically reviewing theories of culturally inclusive learning and Indigenous pedagogical values. It explores perceptual gaps between Indigenous cultural needs and the current use of an LMS through analysis of data collected from Indigenous students and academic staff via an online questionnaire (n = 100) and face-to-face interviews (n = 20) at one Australian university. As a result, it articulates and unpacks mythical perceptions of using an LMS. Consequently, there is clear evidence that Indigenous students expect to experience more human-to-human interactions and develop a sense of community through the use of available communication tools, whereas academic staff tend to rely on a binary opposition between pedagogy and culture in which culture is regarded as a subordinate concept to pedagogy. 相似文献
5.
Ivana Mijatovic Mladen Cudanov Sandra Jednak Djordje M. Kadijevich 《Teaching in Higher Education》2013,18(5):506-517
In this paper, our aim is to explore the predictors of adoption by students of a Learning Management System (LMS) based on a Modular Object-Oriented Dynamic Learning Environment as well as the influence of active student participation and the interactive usage of an LMS on the achievements of students in a blended learning environment. Our study was conducted on 169 students, who are using an LMS for the first time in their studies, from the largest university from Serbia. Our findings indicate that students' active participation in class has a stronger positive effect on students' achievement than does students' interactive usage of the LMS. A stepwise linear regression analysis revealed that a student's interactive usage of the LMS and his/her active participation in class accounted for 47% of the variation in a student's achievement. A student's interactive usage of the LMS is only affected by his/her perceived easy usage of the LMS. 相似文献
6.
This paper provides a point of view on the relationship between learning and knowledge management in corporate training. This relationship forms the framework for the development of an effective learning management system (LMS). It comprises four sections: (1) a theoretical analysis of the relationship between training and knowledge management. In today's corporate environment, characterized by rapid change and restructuring, organizations need to become “learning organizations”; (2) some examples are provided of how training issues are intertwined with other processes, such as sales, communication, research and development (R&D), external network management; (3) corporate universities are the means for achieving those goals. They are efficient as long as they become strategy-supportive organizations. Such a structure is in need of the appropriate technology tool, an LMS; (4) it is possible to underline which functionalities are needed in order to have an efficient LMS. These are the kinds of considerations that led ID Technology in developing LiveLearning. Thus, an LMS for corporate training should take into account the relationship between knowledge management and training. An LMS should allow the integration of training with company processes and should assist in meeting corporate university goals. The same considerations also guide decision makers when choosing an LMS. 相似文献
7.
Paul T. Brinkman 《Research in higher education》1985,23(2):201-218
Ordinary least squares regression (OLS) is often used to estimate the relationship between cost and enrollment. Cost is normally regarded as being a function of enrollment, and the regression equation is structured accordingly. If, however, enrollment is also a function of cost, which some have suggested, then OLS estimates will be biased and inconsistent. The problem is known as simultaneous-equation bias. This study addresses the materiality of this threat in a representative higher-education context. A model is constructed in which it is assumed that cost and enrollment at public two-year colleges are mutually influential. The model is then estimated by both OLS and two-stage least squares regression. The results differ only slightly. This suggests that the prudent use of OLS in similar situations need not be proscribed. 相似文献
8.
A model of the elements of a university brand was developed together with an instrument for measuring how favorably each of these elements was perceived by a sample of young people who were considering entering university. One hundred and ninety-eight students undertaking pre-university courses in two further education colleges in East London completed a questionnaire designed to assess their evaluations of two out of three post-1992 universities covered by the study. The questionnaire contained sections that explored the promises suggested by a university brand, the objective circumstances of an institution, and its symbolic and external representation. Linkages between the favorability of the sample members' perceptions of the main components of a university's brand and the participants' conative, affective, and cognitive responses (including those related to a university's reputation) were also examined. The model involved a mixture of constructs with formative or reflective indicators and thus was estimated using the technique of partial least squares. 相似文献
9.
考虑纵向数据半参数回归模型:Y=Xβ+g(T)+ε,基于最小二乘法和局部线性拟合的方法建立了模型中参数分量β,回归函数g(·)和误差方差σ2的估计量,并在适当条件下得到了它们的渐近正态性和最优收敛速度. 相似文献
10.
实验室管理体制改革的实践和探索 总被引：40，自引：18，他引：40
实验室管理体制是实验室开展教学、科研工作的制度保障。实验室管理体制改革，是促进实验室上规模、上层次、上水平，提高实验室效益的需要，也是适应素质教育和培养具有创新能力的高层次人才的需要。本文从该校近几年的教学实验室体制改革的实践中，对实验室体制改革进行探索和思考。 相似文献
11.
Barbara K. Iverson Ernest T. Pascarella Patrick T. Terenzini 《Research in higher education》1984,21(2):123-136
Based on prior research conducted at residential colleges and universities, nonclassroom informal faculty-student contact appears to be an element of student socialization. This study extends this line of research to a commuter student population. The extent to which informal contact socializes students by influencing their educational aspiration level in a commuter setting is investigated using a longitudinal data collection with the student as unit of analysis. Ordinary least squares and two-stage least squares techniques are used to analyze the data. Significant interactions between informal faculty-student contact and race were found. White and nonwhite students were sbusequently analyzed separately. The ordinary least squares (OLS) multiple regression results suggest that informal contact makes a slight but significant contribution to the explanation of freshmen aspirations for whites, but not for nonwhites. The two-stage least squares (2SLS) analysis suggests that the assumption that contact influences aspiration may not be valid and, indeed, that aspiration level may cause students to seek to initiate informal contact with faculty. 相似文献
12.
The purpose of this study is to examine the impact of perceived brand orientation, intercultural friendship, and university reputation on international students’ course satisfaction and continuance behavioral intention towards the higher education in Malaysia. A total of 348 questionnaires, administered on international students, were collected to empirically test the research model using partial least squares path modeling approach, a structural equation modeling technique for the assessment of measurement and structural model. The empirical results imply that perceived brand orientation and university reputation positively influence course satisfaction and course continuance behavioral intention, while intercultural friendships influences course continuance intention but not course satisfaction. The implications and limitations of research are discussed in the following sections. 相似文献
13.
刘谢进 《楚雄师范学院学报》2006,21(12):47-49
在给定的权回归模型下,讨论了最小二乘估计、最优加权最小二乘估计和线性无偏最小方差估计的性能比较,得出了在随机误差方差矩阵可逆条件下,可算出最优加权最小二乘估计与线性无偏最小方差估计误差方差阵的差表达式,并在一定条件下,两者趋于一致。 相似文献
14.
Online learning has become a conventional term and practice in Australian higher education, yet cultural inclusivity for Indigenous (Indigenous for the purposes of this paper refers to Australian Aboriginal and Torres Strait Islander peoples) students is insufficiently reflected in learning management system (LMS) policies and design. This study aims to explore culturally inclusive learning entrenched in Australian university policies on and practices of LMS by applying Indigenous holistic pedagogical values in LMS design. Based on a literature review, we articulate four dimensions: communication, collaboration, community and interculturality for culturally inclusive learning in an online learning environment. By using the dimensions, we critically review policies (n?=?10) and LMS sites (n?=?50). In this review, we argue that there are contrasts of individually heterogeneous and collectively homogeneous approaches, self-focused and community-driven pedagogy, and task-oriented and relational learning. Significantly, the review results indicate that Indigenous holistic pedagogies have a metaphysical strength to be the ontological foundation for cultural inclusivity. 相似文献
15.
汪朝晖 《南宁师范高等专科学校学报》2008,25(1):138-139
讨论了线性回归模型中未知参数最小二乘估计的改进,引入了一种估计的相对效率,证明了广义根方估计比狭义根方估计的效率较高。 相似文献
16.
时非齐次等式约束线性回归模型回归系数提出广义条件岭估计.证明了在一定的条件下,在均方误差矩阵、均方误差及广义均方误差意义下,广义条件岭估计都优于约束最小二乘估计和狭义条件岭估计. 相似文献
17.
In the presence of omitted variables or similar validity threats, regression estimates are biased. Unbiased estimates (the causal effects) can be obtained in large samples by fitting instead the Instrumental Variables Regression (IVR) model. The IVR model can be estimated using structural equation modeling (SEM) software or using Econometric estimators such as two-stage least squares (2SLS). We describe 2SLS using SEM terminology, and report a simulation study in which we generated data according to a regression model in the presence of omitted variables and fitted (a) a regression model using ordinary least squares, (b) an IVR model using maximum likelihood (ML) as implemented in SEM software, and (c) an IVR model using 2SLS. Coverage rates of the causal effect using regression methods are always unacceptably low (often 0). When using the IVR model, accurate coverage is obtained across all conditions when N = 500. Even when the IVR model is misspecified, better coverage than regression is generally obtained. Differences between 2SLS and ML are small and favor 2SLS in small samples (N ≤ 100). 相似文献
18.
James Law Robert Rush Tom King Elizabeth Westrupp Sheena Reilly 《Child development》2018,89(1):295-309
Oral language development is a key outcome of elementary school, and it is important to identify factors that predict it most effectively. Commonly researchers use ordinary least squares regression with conclusions restricted to average performance conditional on relevant covariates. Quantile regression offers a more sophisticated alternative. Using data of 17,687 children from the United Kingdom's Millennium Cohort Study, we compared ordinary least squares and quantile models with language development (verbal similarities) at 11 years as the outcome. Gender had more of an effect at the top of the distribution, whereas poverty, early language, and reading to the child had a greater effect at the bottom. The picture for TV watching was more mixed. The results are discussed in terms of the provision of universal and targeted interventions. 相似文献
19.
在当今西方经济学至少是所谓的"高级"西方经济理论中,数学已经成为阐述理论内容的基本要素或者说是通用语言.线性回归模型是最常用的经济计量模型,用于研究风险、保险、资产组合等经济问题,也可以用作经济预测.本文研究了线性回归模型中的参数估计问题,运用最小二乘法进行参数估计的数学分析基础.最小二乘法只是使用了函数的稳定点而没有运用数学分析的极值理论里的第一充分条件和第二充分条件,本文讨论最小二乘法的估计参数方法和数学分析的极值理论的方法是等价的. 相似文献
20.
This study proposed to determine the policy of a single university department concerning admissions to the doctoral program. A Q-sort technique was used with several attributes of each graduate listed on an index card. The twelve members of the graduate faculty rated each graduate by placing a profile into one of seven piles. The number in each pile was fixed. Each rater’s policy was captured by using multiple linear regression. With the use of the Judgment Analysis technique (JAN), the raters were placed into appropriate clusters, and it was found that at least two separate judgment systems were present. 相似文献