Abstract: A method, an apparatus for real-time multimedia communications using a software-defined network (SDN) are provided. The method includes receiving, in a periodic manner, a path metric associated with a first service node in the SDN and a second service node in the SDN, wherein the path metric comprises at least one of: a load status of at least one of the first service node or the second service node, or a transmission metric between the first service node and the second service node; and in response to receiving the path metric, updating a cascade network topology comprising an optimal path for transmitting multimedia data between a first edge node and a second edge node.

Abstract: A multi junction laminated laser photovoltaic cell includes a cell unit laminated body and upper and lower electrodes electrically connected with the bottom and top of the cell unit laminated body, respectively, wherein the cell unit laminated body includes more than 6 laminated PN-junction subcells, adjacent two subcells are connected in series via tunnel junctions, wherein each PN-junction subcell uses a semiconductor single crystal material with a specific band gap as the absorption layer, the multiple subcells at least have two different band gaps, and the band gaps of the subcells are arranged in such an order that they decrease successively from the light incidence side to other side of the photovoltaic cell.

Abstract: A measurement method of subcell photocurrents and a matching degree of the subcell photocurrents of a multi-junction photovoltaic cell is provided. The measurement method includes measuring an I-V characteristic of the multi-junction photovoltaic cell; and measuring currents corresponding to respective current steps in an I-V curve to obtain approximate values of short-circuit currents of subcells in the multi-junction photovoltaic cell, and then calculating a mismatching degree of the multi-junction photovoltaic cell using step currents. According to the measurement method, a current mismatching degree of the multi-junction photovoltaic cell is obtained by calculating the mismatching degree of the step currents occurring in the I-V curve. The measurement method is rapid and simple, the measurement method avoids complicated and time-consuming processes where the subcell photocurrents are calculated based on a standard light source spectrum integral with bias lights applied.

Abstract: A measurement method of subcell photocurrents and a matching degree of the subcell photocurrents of a multi-junction photovoltaic cell is provided. The measurement method includes measuring an I-V characteristic of the multi-junction photovoltaic cell; and measuring currents corresponding to respective current steps in an I-V curve to obtain approximate values of short-circuit currents of subcells in the multi-junction photovoltaic cell, and then calculating a mismatching degree of the multi-junction photovoltaic cell using step currents. According to the measurement method, a current mismatching degree of the multi-junction photovoltaic cell is obtained by calculating the mismatching degree of the step currents occurring in the I-V curve. The measurement method is rapid and simple, the measurement method avoids complicated and time-consuming processes where the subcell photocurrents are calculated based on a standard light source spectrum integral with bias lights applied.

Abstract: The present application discloses a multi-junction tandem laser photovoltaic cell, comprising a photovoltaic cell stack and a bottom electrode and a top electrode electrically connected to a bottom and a top of the photovoltaic cell stack, respectively, wherein the photovoltaic cell stack comprises stacked N AlGaAs PN-junction sub-cells, and adjacent sub-cells are connected in series via a tunneling junction, in which N?2. The AlGaAs PN-junction sub-cells use an AlGaAs absorbing layer. The present application further discloses a method of making the multi-junction tandem laser photovoltaic cell. The present application uses AlGaAs as the absorbing layer of the multi-junction tandem cell to convert laser energy, which can effectively increase the open circuit voltage of the photovoltaic cell, thereby significantly improving the conversion efficiency of the photovoltaic cell.

Abstract: A multi junction laminated laser photovoltaic cell includes a cell unit laminated body and upper and lower electrodes electrically connected with the bottom and top of the cell unit laminated body, respectively, wherein the cell unit laminated body includes more than 6 laminated PN-junction subcells, adjacent two subcells are connected in series via tunnel junctions, wherein each PN-junction subcell uses a semiconductor single crystal material with a specific band gap as the absorption layer, the multiple subcells at least have two different band gaps, and the band gaps of the subcells are arranged in such an order that they decrease successively from the light incidence side to other side of the photovoltaic cell.

Abstract: A method, an apparatus for real-time multimedia communications using a software-defined network (SDN) are provided. The method includes receiving, in a periodic manner, a path metric associated with a first service node in the SDN and a second service node in the SDN, wherein the path metric comprises at least one of: a load status of at least one of the first service node or the second service node, or a transmission metric between the first service node and the second service node; and in response to receiving the path metric, updating a cascade network topology comprising an optimal path for transmitting multimedia data between a first edge node and a second edge node.

Abstract: A method, an apparatus, and a system for real-time multimedia communications using a software-defined network (SDN) are provided. The method includes receiving, by a processor, a path metric indicative of transmission capacity between directly-connected service nodes in the SDN, determining, by the processor based on the path metric, a cascade network topology comprising an optimal path between a first edge node and a second edge node, wherein the optimal path has the lowest transmission latency among data transmission paths in the SDN between the first edge node and the second edge node, and based on a determination that multimedia data is to be transmitted between the first edge node and the second edge node, transmitting the multimedia data between the first edge node and the second edge node in accordance with the optimal path.

Abstract: The present application discloses a multi-junction tandem laser photovoltaic cell, comprising a photovoltaic cell stack and a bottom electrode and a top electrode electrically connected to a bottom and a top of the photovoltaic cell stack, respectively, wherein the photovoltaic cell stack comprises stacked N AlGaAs PN-junction sub-cells, and adjacent sub-cells are connected in series via a tunneling junction, in which N?2. The AlGaAs PN-junction sub-cells use an AlGaAs absorbing layer. The present application further discloses a method of making the multi-junction tandem laser photovoltaic cell. The present application uses AlGaAs as the absorbing layer of the multi-junction tandem cell to convert laser energy, which can effectively increase the open circuit voltage of the photovoltaic cell, thereby significantly improving the conversion efficiency of the photovoltaic cell.

Abstract: A method, an apparatus, and a system for real-time multimedia communications using a software-defined network (SDN) are provided. The method includes receiving, by a processor, a path metric indicative of transmission capacity between directly-connected service nodes in the SDN, determining, by the processor based on the path metric, a cascade network topology comprising an optimal path between a first edge node and a second edge node, wherein the optimal path has the lowest transmission latency among data transmission paths in the SDN between the first edge node and the second edge node, and based on a determination that multimedia data is to be transmitted between the first edge node and the second edge node, transmitting the multimedia data between the first edge node and the second edge node in accordance with the optimal path.