The Timeliness of the Reserved Service in the Cluster with the Regulation of the Time of Destruction of Overdue Requests in the Node Queues

With the increasing complexity of distributed control tasks based on their intellectualization, there are problems of insufficient time and computing resources for functioning in real time. In this regard, there is a need to develop methods for organizing distributed real-time computer systems, based on the consolidation of distributed computing resources with their integration into clusters. The possibilities of increasing the probability of timely servicing of waiting- critical requests in the cluster as a result of query replication and controlling the time of destruction of potentially expired replicas in node queues are investigated. The cluster is represented as a group of queuing systems with infinite queues with a limited average waiting time. The effectiveness of the reserved service of a real-time request is determined by the probability of executing at least one of the generated copies of the request in the maximum allowable time without losing it due to errors and waiting time limits in the queues of cluster nodes. It is shown that there is an optimal multiplicity of query replication with a significant influence of the choice of restrictions on the waiting time for requests in queues before they are destroyed.

Hydraulic Responses and Flow Regulation in Multi-Demand Water Transfer Systems

It is of great significance for the practical operation scheduling to comprehensively analyze the influencing factors of the long-term steady-state operation state of different water demand scenarios and the coupled operation of hydraulic facilities when switching demand scenario as the demand changes. In the study, a case study is performed in the Daxing Branch project, the numerical model of which considered pipelines, pumps, valves, air valves, and regulating tanks is established using Method of Characteristics. The hydraulic responses and corresponding flow regulation of different demand scenarios and between changing demand scenarios are analyzed. The results show that steady-state working conditions can have important impacts on the transient process. Energy consumption and the amount of water transfer, as well as water hammer pressure and the allowable reaction time during the transient process should be taken into account in the selection of long-term steady-state working conditions of different demand scenarios. The sequence and maximum allowable time interval of the coupled operation of pumps and valves should be considered when switching demand scenario. Finally, the optimal steady-state working conditions of different demand scenarios, the coupled operation sequence of pumps and valves, the maximum allowable time interval of the Daxing Branch project are proposed, which can provide some insights into the safe operation of the project and other similar complex water transfer projects.

Delayed Consensus Problem for Single and Double Integrator Systems

This work deals with the analysis of the consensus problem for networks of agents constituted by single and double integrator systems. It is assumed that the communication among agents is affected by a constant time-delay. Previous and numerous analysis of the problem shows that the maximum communication time-delay that can be introduced to the network without affecting the consensus of the group of the agents depends on the considered topology. In this work, a control scheme that is based on the estimation of future states of the agents and that allows increasing the magnitude of a possible time-delay affecting the communication channels is proposed. How the proposed delay compensation strategy is independent of the network topology in the sense that the maximum allowable time-delay that could be supported by the network depends on a design parameter and not on the maximum eigenvalue of the corresponding Laplacian matrix is shown. It is formally proven that, under the proposed prediction scheme, the consensus of the group can be achieved by improving the maximum time-delay bounds previously reported in the literature. Numerical simulations show the effectiveness of the proposed solution.