In past decades, there has been a growing interest in the discussion and study of using underwater acoustic channel as the physical layer for communication systems, ranging from point-to-point communications to underw...In past decades, there has been a growing interest in the discussion and study of using underwater acoustic channel as the physical layer for communication systems, ranging from point-to-point communications to underwater multicarrier modulation networks. A series of review papers were already available to provide a history of the development of the field until the end of the last decade. In this paper, we attempt to provide an overview of the key developments, both theoretical and applied, in the particular topics regarding multicarrier communication for underwater acoustic communication such as the channel and Doppler shift estimation, video and image transmission throw multicarrier techniques, etc. This paper also includes acoustic propagation properties in seawater and underwater acoustic channel representation.展开更多
Smart grid constrained optimal control is a complex issue due to the constant growth of grid complexity and the large volume of data available as input to smart device control.In this context,traditional centralized c...Smart grid constrained optimal control is a complex issue due to the constant growth of grid complexity and the large volume of data available as input to smart device control.In this context,traditional centralized control paradigms may suffer in terms of the timeliness of optimization results due to the volume of data to be processed and the delayed asynchronous nature of the data transmission.To address these limits of centralized control,this paper presents a coordinated,distributed algorithm based on distributed,local controllers and a central coordinator for exchanging summarized global state information.The proposed model for exchanging global state information is resistant to fluctuations caused by the inherent interdependence between local controllers,and is robust to delays in information exchange.In addition,the algorithm features iterative refinement of local state estimations that is able to improve local controller ability to operate within network constraints.Application of the proposed coordinated,distributed algorithm through simulation shows its effectiveness in optimizing a global goal within a complex distribution system operating under constraints,while ensuring network operation stability under varying levels of information exchange delay,and with a range of network sizes.展开更多
The heterogeneous nature of smart grid components and the desire for smart grids to be scalable,stable and respect customer privacy have led to the need for more distributed control paradigms. In this paper we provide...The heterogeneous nature of smart grid components and the desire for smart grids to be scalable,stable and respect customer privacy have led to the need for more distributed control paradigms. In this paper we provide a distributed optimal power flow solution for a smart distribution network with separable global costs, separable non-convex constraints, and inseparable linear constraints,while considering important aspects of network operation such as distributed generation and load mismatch, and nodal voltage constraints. An asynchronous averaging consensus protocol is developed to estimate the values of inseparable global information. The consensus protocol is then combined with a fully distributed primal dual optimization utilizing an augmented Lagrange function to ensure convergence to a feasible solution with respect to power flow and power mismatch constraints. The presented algorithm uses only local and neighbourhood communication to simultaneously find the mismatch between power generation, line loss and loads, to calculate nodal voltages,and to minimize distributed costs, leading to a completely distributed solution of the global problem. An IEEE test feeder system with a reasonable number of nodes is used to illustrate the proposed method and efficiency.展开更多
文摘In past decades, there has been a growing interest in the discussion and study of using underwater acoustic channel as the physical layer for communication systems, ranging from point-to-point communications to underwater multicarrier modulation networks. A series of review papers were already available to provide a history of the development of the field until the end of the last decade. In this paper, we attempt to provide an overview of the key developments, both theoretical and applied, in the particular topics regarding multicarrier communication for underwater acoustic communication such as the channel and Doppler shift estimation, video and image transmission throw multicarrier techniques, etc. This paper also includes acoustic propagation properties in seawater and underwater acoustic channel representation.
文摘Smart grid constrained optimal control is a complex issue due to the constant growth of grid complexity and the large volume of data available as input to smart device control.In this context,traditional centralized control paradigms may suffer in terms of the timeliness of optimization results due to the volume of data to be processed and the delayed asynchronous nature of the data transmission.To address these limits of centralized control,this paper presents a coordinated,distributed algorithm based on distributed,local controllers and a central coordinator for exchanging summarized global state information.The proposed model for exchanging global state information is resistant to fluctuations caused by the inherent interdependence between local controllers,and is robust to delays in information exchange.In addition,the algorithm features iterative refinement of local state estimations that is able to improve local controller ability to operate within network constraints.Application of the proposed coordinated,distributed algorithm through simulation shows its effectiveness in optimizing a global goal within a complex distribution system operating under constraints,while ensuring network operation stability under varying levels of information exchange delay,and with a range of network sizes.
文摘The heterogeneous nature of smart grid components and the desire for smart grids to be scalable,stable and respect customer privacy have led to the need for more distributed control paradigms. In this paper we provide a distributed optimal power flow solution for a smart distribution network with separable global costs, separable non-convex constraints, and inseparable linear constraints,while considering important aspects of network operation such as distributed generation and load mismatch, and nodal voltage constraints. An asynchronous averaging consensus protocol is developed to estimate the values of inseparable global information. The consensus protocol is then combined with a fully distributed primal dual optimization utilizing an augmented Lagrange function to ensure convergence to a feasible solution with respect to power flow and power mismatch constraints. The presented algorithm uses only local and neighbourhood communication to simultaneously find the mismatch between power generation, line loss and loads, to calculate nodal voltages,and to minimize distributed costs, leading to a completely distributed solution of the global problem. An IEEE test feeder system with a reasonable number of nodes is used to illustrate the proposed method and efficiency.
