This quasi-experimental study set out to examine the effect of peer corrective feedback on feedback givers and receivers in L2 writing. The forms in focus were a/an, the, and the past tense.The study was conducted in an EFL classroom setting with 45 learners of English in three writing classes which served as the feedback givers, receivers, and the control group.  Over four sessions of treatmen...

introduction: evaluation of students’ learning in clinical education system is one of the most important and challenging issues that facilities in this field have been facing. the present study aimed to evaluate the role of feedback during evaluation in increasing emergency medicine residents’ clinical skills. method: the present experimental study was performed on all second year emergency med...

The thesis investigates the reliable transport from one sender to a group of receivers (multicast). It is often stated that network support is required to allow for efficient reliable multicast. This thesis shows that this is not the case. Efficient reliable multicast is possible on a pure end-to-end basis even for a very large number of receivers. In the case of data loss in the network, relia...

Reliable multicast protocols suuer from the problem of feedback implosion. To avoid this problem, the number of receivers sending feedback in case of loss must be small. However, losses experienced by diierent receivers are strongly correlated, since receivers share common resources in the multicast tree. One approach to feedback implosion avoidance relies on delaying feedback at the receivers....

In multicast communication, it is often required that feedback is received from a potentially very large group of responders while at the same time a feedback implosion needs to be prevented. To this end, a number of feedback control mechanisms have been proposed, which rely either on tree-based feedback aggregation or timer-based feedback suppression. Usually, these mechanisms assume that it i...

In a large RTP session using the RTP Control Protocol (RTCP) feedback mechanism defined in RFC 4585, a feedback target may experience transient overload if some event causes a large number of receivers to send feedback at once. This overload is usually avoided by ensuring that feedback reports are forwarded to all receivers, allowing them to avoid sending duplicate feedback reports. However, th...

We investigate the scalability of feedback in multicast communication and propose a new method of probabilistic feedback based on exponentially distributed timers. By analysis and simulation for up to 106 receivers we show that feedback implosion is avoided with good latency performance obtained. The mechanism is robust against the loss of feedback messages and robust against homogeneous and he...

Reliable multicast applications use feedback messages to report receiving status of receivers. This results in the well-known feedback implosion and scalability problems. Also, quick loss response from receivers and low multicast overhead, e.g. control messages and session messages, are desired. We present a feedback implosion control mechanism that groups the multicast members into areas, with...

One of the new challenges posed by multipoint applications in future networks is scalable multicast error control. Current error control mechanisms do not scale because they do not deal with message implosion, caused by synchronized feedback messages (e.g. positive or negative acknowledgments) from the receivers in a multicast connection. Implosion control can be performed by the receivers or t...