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111.
Shermis MD Rasmussen JL Rajecki DW Olson J Marsiglio C 《Journal of applied measurement》2001,2(2):154-170
Scores assigned to college placement essays by a computer program (PEG) showed high agreement with the evaluations of human readers (r =.82). Further, both types of graders tended to assign higher or lower scores to essays written about particular topics. Content analyses by a second program (MCCA) indicated that themes in essays varied in terms of emphasis on "analytic," "emotional," or "practical" dimensions. Human and machine readers tended to give higher scores for analytic and practical themes, and lower scores for those involving emotion. The ranks of mean prompt-related grades were concordant with the ranks of mean analytic and practical content across topics. Such findings call for the refined standardization of prompts for future testing, and the need for care in the evaluation of existing essays. 相似文献
112.
In this letter, a general concatenated code structure is presented, encompassing both parallel and serially concatenated codes as special cases. The structure provides a unifying framework for the analysis of concatenated codes and offers new degrees of freedom for code design. Performance analysis based on error bounds in the error floor region and suggestions for suitable design criteria are provided, together with a design approach for the waterfall region. The proposed structure allows for constructing very high-rate codes with no penalty in the error floor region and good performance in the waterfall region 相似文献
113.
Kallesoe C.S. Izadi-Zamanabadi R. Vadstrup P. Rasmussen H. 《Industry Applications, IEEE Transactions on》2007,43(4):1022-1031
This paper addresses the subject of interturn short circuit estimation in the stator of a delta-connected induction motor. In this paper, an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit, and an expression of the current in the short circuit. Moreover, the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has occurred in the motor. To be able to develop this observer, a model that is particularly suitable for the chosen observer design, is also derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate interturn short-circuit faults. 相似文献
114.
Most studies that have investigated the use of coarsely grained scales have indicated that the accuracy of statistics calculated on such scales is not compromised as long as the scales have about 5 or more points. Gregoire and Driver (1987), however, found serious perturbances of the Type I and Type II error rates using a 5-point scale. They carried out three computer simulation experiments in which continuous data were transformed to Likert-scale values. Two of the three experiments are shown to be flawed because the authors incorrectly specified the population mean in their simulation. This article corrects the flaw and demonstrates that the Type I and Type II error rates are not seriously compromised by the use of ordinal-scale data. Furthermore, Gregoire and Driver's results are reinterpreted to show that in most cases, the parametric test of location equality shows a power superiority to the nonparametric tests. Only in their most nonnormal simulation does a nonparametric test show a power superiority. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
115.
N Noviski JP Brewer WA Skornik SJ Galli JM Drazen TR Martin 《Canadian Metallurgical Quarterly》1999,86(1):202-210
Exposure to ambient ozone (O3) is associated with increased exacerbations of asthma. We sought to determine whether mast cell degranulation is induced by in vivo exposure to O3 in mice and whether mast cells play an essential role in the development of pulmonary pathophysiological alterations induced by O3. For this we exposed mast cell-deficient WBB6F1-kitW/kitW-v (kitW/kitW-v) mice and the congenic normal WBB6F1 (+/+) mice to air or to 1 or 3 parts/million O3 for 4 h and studied them at different intervals from 4 to 72 h later. We found evidence of O3-induced cutaneous, as well as bronchial, mast cell degranulation. Polymorphonuclear cell influx into the pulmonary parenchyma was observed after exposure to 1 part/milllion O3 only in mice that possessed mast cells. Airway hyperresponsiveness to intravenous methacholine measured in vivo under pentobarbital anesthesia was observed in both kitW/kitW-v and +/+ mice after exposure to O3. Thus, although mast cells are activated in vivo by O3 and participate in O3-induced polymorphonuclear cell infiltration into the pulmonary parenchyma, they do not participate detectably in the development of O3-induced airway hyperresponsiveness in mice. 相似文献
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The purpose of this study was to examine differences in postprandial hypertriglyceridemia (PP-HTG) and low density lipoprotein (LDL) subfraction distribution among groups of men and women with different fitness levels. Fifty-four men and women (ages 30-53 yr) were recruited based on their previous two-year activity level: sedentary (S), recreational exercisers (R), and endurance trained (T). After a 24-h dietary preparation, blood was collected, and LDL subfractions were separated and analyzed for cholesterol (C) and apoprotein B100. Plasma triglyceride (TG) concentration was assessed before and at 2, 4, 6, and 8 h after fat meal. PP-HTG was significantly higher for the S group compared with the two activity groups. LDL3-C and LDL3-apoprotein B100 were significantly higher for the S group compared with the T group and for men compared with women. These findings suggest that both recreational and competitive aerobic training are associated with a lower TG response after a fatty meal. However, higher volume aerobic training may be necessary to reduce the number of dense LDL molecules and their cholesterol content. 相似文献