数字化学习中运用多媒体(上)

本文通过回顾12条基于研究的教学设计原则,说明了如何设计计算机辅助多媒体教学材料来促进学习。首先介绍了多媒体原则(根据五个对照实验得到的中值效应量为d=1.67),其主张在计算机辅助教学中,语词和图像同时呈现的效果比只呈现语词的效果要好。无关认知加工做的是和教学目标无关的事情。为了减少无关认知加工,提出的教学原则有聚焦要义(d=0.70)、标记结构(d=0.46)、控制冗余(d=0.87)、空间邻近(d=0.79)和时间邻近(d=1.30)。基本认知加工的功能在于对基本材料进行心理表征。为了调节基本认知加工,提出的教学原则有分段呈现(d=0.70)、预先准备(d=0.46)和双重通道(d=0.72)。生成认知加工的功能是为了建构材料的意义。为了促进生成认知加工,提出的教学原则有个性化(d=0.79)、人声化(d=0.74)和具身化(d=0.36)。部分原则有边界条件,例如有的原则对新手学习者比对专家学习者更有效。     

Changes in tibiofemoral contact forces during running in response to in-field gait retraining

We evaluated the efficacy of an in-field gait retraining programme using mobile biofeedback to reduce cumulative and peak tibiofemoral loads during running. Thirty runners were randomised to either a retraining group or control group. Retrainers were asked to increase their step rate by 7.5% over preferred in response to real-time feedback provided by a wrist mounted running computer for 8 routine in-field runs. An inverse dynamics driven musculoskeletal model estimated total and medial tibiofemoral joint compartment contact forces. Peak and impulse per step total tibiofemoral contact forces were immediately reduced by 7.6% and 10.6%, respectively (P < 0.001). Similarly, medial tibiofemoral compartment peak and impulse per step tibiofemoral contact forces were reduced by 8.2% and 10.6%, respectively (P < 0.001). Interestingly, no changes were found in knee adduction moment measures. Post gait retraining, reductions in medial tibiofemoral compartment peak and impulse per step tibiofemoral contact force were still present (P < 0.01). At the 1-month post-retraining follow-up, these reductions remained (P < 0.05). With these per stance reductions in tibiofemoral contact forces in mind, cumulative tibiofemoral contact forces did not change due to the estimated increase in number of steps to run 1 km.     

Transfer of oddity learning in the pigeon

Two pigeons were trained on a six-key modified oddity-from-sample procedure. The stimuli were olor pictures of birds, butterflies, and human faces. Initially, the third peck on the sample key which presented one of three different bird pictures) lit only one comparison key. Every three dditional pecks on the sample illuminated another comparison key. Fifteen sample pecks produced he maximum of five comparison stimuli. A peck on the comparison key that presented the non-atching bird picture produced grain. Pecks on matching keys turned off all the comparison keys nd repeated the trial. The birds learned to peck each sample until the non-matching comparison timulus was produced, and then to peck that key. After acquisition (70%–90% accuracy), the hree bird stimuli were replaced by a new set of three bird pictures. Subsequent phases provided ew sets of bird, butterfly, and human face stimuli. Both birds showed transfer of oddity learning o the novel samples. The data suggest that the birds may have been engaging in conceptual-type oddity learning, rather than learning discrete five-key discriminations or a series of two component chains.     

我是传奇(英文)

在一次可怕的疫病传遍世界后,人们变成了夜间活动的嗜血魔物(bloodthirsty,nocturnal creatures),只有罗伯特·奈维尔幸免于难,但同时也成为变种人的猎物。白天,他四处奔波,努力寻找可能的生存者并消灭被感染的吸血鬼们(stalking the infected monstrosities);夜晚,他蜷缩在家中祈祷黎明赶快到来(barricades himself in his home and prays for dawn)……这部恐怖小说(horror)的同名电影由威尔·史密斯主演,刚上映,就获得周票房冠军;同时,小说也获得了一致好评。下面这一段就是我们唯一的幸存者白天的活动情况。     

The importance of measuring growth in response to intervention models: Testing a core assumption

A core assumption of response to instruction or intervention (RTI) models is the importance of measuring growth in achievement over time in response to effective instruction or intervention. Many RTI models actively monitor growth for identifying individuals who need different levels of intervention. A large-scale (N=23,438), two-year longitudinal study of first grade children was carried out to compare the predictive validity of measures of achievement status, growth in achievement, and their combination for predicting future reading achievement. The results indicate that under typical conditions, measures of growth do not make a contribution to prediction that is independent of measures of achievement status. These results question the validity of a core assumption of RTI models.     

Conducting Simulation Studies in Psychometrics

Simulation studies are fundamental to psychometric discourse and play a crucial role in operational and academic research. Yet, resources for psychometricians interested in conducting simulations are scarce. This Instructional Topics in Educational Measurement Series (ITEMS) module is meant to address this deficiency by providing a comprehensive introduction to the topic of simulation that can be easily understood by measurement specialists at all levels of training and experience. Specifically, this module describes the vocabulary used in simulations, reviews their applications in recent literature, and recommends specific guidelines for designing simulation studies and presenting results. Additionally, an example (including computer code in R) is given to demonstrate how common aspects of simulation studies can be implemented in practice and to provide a template to help users build their own simulation.