In this paper, a network of communicating logic programs is proposed as a model for concurrent programming based on logic programs with explicit channels of communications. On the assumption that the denotations of channels are defined by using a sequence domain, semantics for unbounded nondeterminism caused by logic programs is dealt with and the whole network is defined as an extension of Kahn's pure dataflow. A denotational semantics for the whole network is defined by a recursive relation set as to the histories of channels. The method to investigate extensionality of input-output histories on the node in nondeterministic dataflow is not applicable to the proposed network, because the node is a logic program. Fairness is required for unbounded nondeterminism to describe the behaviour of the whole network. And in this paper the corresponding semantics of the network is shown. We have a method of defining a continuous function which is associated with the network, based on histories of channels. The least fixpoint of the function is regarded as a denotational semantics for the whole network, to reflect its fair behaviours.

Two approaches are known for enhancing the fault tolerance of systolic arrays through reconfiguration. They are different in the bypassing function. One leads to an easier reconfiguration procedure, whereas the other provides better utilization of nonfaulty cells. It seems that both approaches may have the same probability of successful reconfiguration for practical failure rates of cells but not for all other failure rates. In this paper, we investigate this supposition, and conclude that the two approaches perform equally well for all practical cell failure rates and array sizes.