Asynchronous messaging

Connectors that support explict call and return The call could be synchronous or asynchronous. Asynchronous messages could be queued until processed, and return values could be treated as futures5 or callbacks. 

Caughey et al. 1998] S.J. Caughey, M.C. Little and S.K. Shrivastava. Checked Transactions in an Asynchronous Message Passing Environment, in 1st IEEE International Symposium on Object-Oriented Real-time Distributed Computing, pp. 222-229,... 

The separation of students and tutor in space and time during the CZM online module involved an asynchronous system where messages were posted on online forums for use by learners at different time periods. T-leaming of CZM was flexible and adaptable so that learners could study anywhere and anytime. Networked learning... 

Synchronous communication comprises services such as audio-visual realtime data exchange, which can be used for conferences between locally distributed design team members. Asynchronous tools such as email or audio message allow communication if the team members are not available simultaneously. 

Another distinction to be made regarding communication is that between the synchronous exchange of knowledge, where partners can communicate at the same time, and the asynchronous exchange, where the transmission and the reception of the message do not happen simultaneously, such as the sending of documents via e-mail. 

When communication occurs in real time, be that face to face, using telephony or electronic instant messaging it is clear to all parties that transmission and receipt of information has occurred. But when we interact asynchronously through systems such as email or application specific messaging we accept that there will probably be a delay until we hear from the redpient The sender may or may not expect an acknowledgement and the receiver may or may not send one irrespective of whether they actually action the content of the message. In this way there are many opportunities for the sender to believe that they have achieved communication when this is not the case. 

The timed asynchronous protocol uses the transmission of local clock values and the bounded drift values to classify all messages (when received) to be either fast or slow. Fast messages are correct messages, i.e., they are never too fast. The protocol guarantees the following ... 

One can look at society at many different scales one finds parallel computers from neurons in the brain, to bees in a swarm, to people in society. In every case, the underlying methodology is that of asynchronous computing elements (neurons, bees, people) communicating by messages. This so-called message-passing MIMD computer... 

The CSD inputs/outputs are messages sent from or to the peripherals. These messages are SACEM encoded and securely date messages. The transmission of messages between CSD and DESP is asynchronous. 

The ONBOARD ERTMS equipment receives messages from beacons on the track and radio messages in a completely asynchronous way. The devices store these messages containing a large amount of information (track profile over several kilometers) in order to continnously and secmely control the movement of the train. 

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