Top-down and bottom-up guidance in comprehension of schematic football diagrams

Comprehension of a narrated diagram entail complex cognitive processing as learner is challenged to extract the orally evoked information. The present experiment examined the effects of 2 different forms of attention guidance – bottom-up and top-down – on comprehension performance, cognitive load investment, and motivation to learn, using a 2 × 2 mixed design with factors “Expertise” (Expert vs. Novice) and “Condition” (no-signal, circle, segment). The results revealed an expertise reversal effect indicating that the incorporation of visual signals in diagram is effective for novice learners but partially reverses and becomes ineffective for more experienced learners (even though they invested less mental effort and reported higher level of motivation in the segmented condition). The findings suggested that the effectiveness of instructional guidance depends heavily on levels of prior knowledge.     

数字无中心通信系统的信令设计

本文介绍了无中心多信道选址移动通信系统,为这一系统的全面数字化设计了新的数字信令,并详细介绍了这套数字信令的帧构造过程及关键域的参考设置。同时这套数字信令还具有良好的差错控制性能,最后通过在Systemview下的仿真证明了它的差错控制确实能大幅优化系统误码率。