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972.
973.
In this paper, a novel reconstruction technique based on level set method and algebraic reconstruction technique is proposed for multiphase flow computed tomography (CT) system. The curvature-driven noise reduction method is inserted into the conventional iteration procedure of algebraic reconstruction technique to improve the image quality and convergence speed with limited projection data. By evolving the image as a set of iso-intensity contours after each updation, the sufficient number of iterations for acceptable results is reduced by 80%-90%, while the image quality is enhanced obviously. Quantitative evaluation of image quality is given by using both relative image error and correlation coefficient. The resultant images can be utilized to detect flow regimes for monitoring industrial multiphase flow. Laboratory results demonstrate the feasibility of the proposed method. Phantoms of four typical flow regimes can be reconstructed from few-view projection data efficiently, and the corresponding image errors and correlation coefficients are acceptable for the cases tested in this paper. 相似文献
974.
Considering the uncertainty of material performance, geometric characteristic and analysis method, the analysis of statistical parameters of the resistance of cast ball-and-socket support joints and the reliability analysis are carried out by JC method (improved first-order second-moment method) based on the relevant experimental data. Results show that the resistance partial factor of the joint increases with the increase of the reliability index. The resistance partial factors are suggested corresponding to the reliability index under different load combinations. Moreover, the suggested resistance partial factor is adopted in reliability design, and it is found that the reliability index of the joint is larger than the target reliability index. The optimal load combination is the one in which live load plays an important control role. Finally, based on the suggested resistance partial factors, the reliability analysis of cast ball-and-socket support joints of a project is conducted. 相似文献
975.
Tonia A. Dousay Natasha P. Trujillo 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(2):876-887
Existing research highlights conflicting results attempting to capture gender preferences with respect to unimodal versus multimodal designs in online learning. As online learning continues to expand, more research examining the role of gender in multimedia design holds considerable potential. However, the presence of multimedia in online learning contexts presents a more complex problem when taking into consideration the concept of learner interest. The current study sought to investigate gender differences in situational interest (SI) with respect to three different but related designs of an online, multimedia learning environment for continuing, professional education in emergency medical services. The content in these designs was identical, but applied different combinations of the redundancy and modality multimedia principles. A two-way analysis of variance was used to examine the types of SI by gender and type of multimedia design. While no significant difference or interaction effect was identified between gender and triggered SI, an interaction effect was observed for females and the different multimedia designs. Specifically, females reported a higher maintained SI when animation, narration and text were effectively combined. The findings of this study provide insight into best practices for instructional and media designers developing multimedia learning environments as well as future research implications. 相似文献
976.
Katharine H. Zeiders Sara D. Bayless Chelsea L. Derlan Adriana J. Umaña-Taylor Kimberly A. Updegraff Laudan B. Jahromi 《Child development》2019,90(3):e373-e385
Ethnic–racial identity (ERI) development and ethnic–racial discrimination are two salient experiences among adolescents in the United States. Despite growing awareness of the costs and benefits of these experiences individually, we know little about how they may influence one another. The current study examined competing hypotheses relating discrimination and components of ERI (i.e., exploration, resolution, affirmation) among a sample of Mexican-origin adolescent mothers (N = 181; Mage at Wave 1 = 16.83, SD = 1.01) across six waves of data. Findings revealed that within-person changes in discrimination predicted subsequent ERI resolution and affirmation; however, ERI did not predict subsequent discrimination. Between-person effects of discrimination on affirmation were significant. Our findings underscore the importance of discrimination experiences in shaping Mexican-origin adolescent mothers’ normative developmental competencies. 相似文献
977.
Allison P. Mugno Lindsay C. Malloy Daniel A. Waschbusch William E. Pelham Jr. Victoria Talwar 《Child development》2019,90(3):774-789
Children's lie-telling is surprisingly understudied among children with significant behavioral problems. In the present study, experimental paradigms were used to examine antisocial lie-telling among ethnically diverse 5- to 10-year-old children with disruptive behavior disorders (DBD; n = 71) and a typically developing (TD) comparison sample (n = 50) recruited from a southeastern state from 2013 to 2014. Children completed two games that measured the prevalence and skill of their lies: (a) for personal gain and (b) to conceal wrongdoing. Children with DBD were more likely to lie for personal gain than TD children. With age, children were more likely to lie to conceal wrongdoing, but the reverse was true regarding lies for personal gain. Results advance knowledge concerning individual differences in children's lie-telling. 相似文献
978.
979.
Hae Yeon Lee Jeremy P. Jamieson Adriana S. Miu Robert A. Josephs David S. Yeager 《Child development》2019,90(6):e849-e867
Grades often decline during the high school transition, creating stress. The present research integrates the biopsychosocial model of challenge and threat with the implicit theories model to understand who shows maladaptive stress responses. A diary study measured declines in grades in the first few months of high school: salivary cortisol (N = 360 students, N = 3,045 observations) and daily stress appraisals (N = 499 students, N = 3,854 observations). Students who reported an entity theory of intelligence (i.e., the belief that intelligence is fixed) showed higher cortisol when grades were declining. Moreover, daily academic stressors showed a different lingering effect on the next day's cortisol for those with different implicit theories. Findings support a process model through which beliefs affect biological stress responses during difficult adolescent transitions. 相似文献
980.