Integrated and Control-Oriented Simulation Tool for Optimizing Urban Drainage System Operation

With the management and operation of urban drainage systems (UDS) becoming more complicated and difficult, integrated models aiming to control and manage the entire drainage system are under enormous demand. Ideally, integrated models, as a potential tool for meeting the increasing demands, should combine both conceptual and mechanistic models that merge all UDS components and balance simulation accuracy with time constraints. Within this context, our study introduces an innovative modeling software, Simuwater, which couples multiple principles, simulates multiple components, and combines optimized control functions, playing a role in the integrated simulation and overflow control application of UDS. The software has been utilized in a real-time case-control study in one city of China, and it obtained significant optimized operation results to reduce combined sewer overflow (CSO) by making full use of the storage facilities and actuators. As the Simuwater model continues to improve in depth and breadth, it will play an increasingly important role in more application scenarios of UDS.

Research on Intersection Frequent Overflow Control Strategy Based on Wide-Area Radar Data

Overflow identification and control at urban road intersection is a derivative problem of oversaturation control. The existing cross-section detector uses the road cross-section occupation of vehicles to identify the overflow state; then, the downstream road condition is often ignored. At present, more and more advanced traffic detection technologies, such as vehicle-to-infrastructure and wide-area radar, can provide reliable data for accurate overflow identification. In this paper, a new method of overflow identification and control at intersections is proposed by using advanced wide-area radar detection data. As a detector for specific segment of road, the wide-area radar can detect the traffic flow data in a certain range of road and provide more data types. Therefore, the average speed and space occupancy of the effective detection road segment are selected as subindicators to establish the comprehensive identification index of overflow identification. Then, the overflow control strategy is developed considering the traffic demand of the overflow phase and the nonoverflow phase. It is proved that the method is more accurate and effective in overflow identification and control by using simulation experiment of field data.

An Efficient Buffer Overflow Control Scheme to Mitigate Packet Loss in Manets

MANET (Mobile Ad hoc Network) is self-configuring, self-organizing, infrastructure-less network of mobile devices connected without wires. Because of the dynamic changes in the network topology, there is no centralized control in ad hoc networks. So, mobile nodes can communicate with each other via intermediate nodes. The buffer size of intermediate nodes plays a significant role to hold packets in the buffer before dropping the newly arrived packets. In MANET, buffer overflow (congestion) occurs in any intermediary nodes when data packets pass through source to destination and incurs packet loss, which causes the performance degradations of a network. Congestion can be reduced by using several Active Queue Management [AQM] techniques. Queue Management Node or “QMN” is an active queue management strategy to control packet drops by assigning space of a buffer node to all its neighbouring nodes dynamically depending upon the total number of packets received from its neighbours. In this scheme, authors did not take into account the impact of collaboration between neighbors of a central node. They only consider the characteristics of nodes, while ignoring the message properties in MANET. And also a new node has to be waiting until it will get enough equal space from the QMN along with other neighbor nodes. During this waiting period, high packet loss can be occurred. So, an efficient buffer overflow control scheme is required to make sure every node has adequate storage space to hold the data once the buffer of the node is near to congestion. In this paper, we proposed a scheme that integrates QMN technique with combinational buffer management (CBM) strategy, which includes both the features of messages and nodes, and transfer the duplicated messages to neighbour node for total utility optimization, rather than deleting them. By using this scheme packet loss can be mitigated in MANETs efficiently. Our simulation results here reveal that, the proposed scheme achieves better performance than other existing schemes in terms of packet delivery ratio, throughput, overhead ratio and end to end delay .