This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two pe...This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.展开更多
In this paper, distributed relay diversity systems are analyzed, modeled and evaluated in an Orthogonal Frequency Division Multiplexing (OFDM) based networks. The investigated distributed relay diversity schemes exten...In this paper, distributed relay diversity systems are analyzed, modeled and evaluated in an Orthogonal Frequency Division Multiplexing (OFDM) based networks. The investigated distributed relay diversity schemes extend the ideas of a single hop transmit antenna schemes such as Cyclic Delay Diversity (CDD), Space Time Transmit Diversity (STTD), transmit Coherent Combining (CC) and Selection Diversity (SD) to distributed diversity systems. In contrast to the classical single hop system, the antennas in the distributed systems belongs to distributed relays instead of being co-located at the transmitter. The distributed relay diversity methods considered in this paper: Relay CDD (RCDD), Relay Alamouti (i.e.STTD), Relay CC (RCC) and Relay SD (RSD) are compared to the traditional 1-hop system. Analytical expressions for the received Signal to Interference Noise Ratio (SINR) are derived and used in a dynamic multi-cell multi-user simulator. Results show considerable SINR gains for both Round Robin and Max-SINR schedulers. The SINR gains translate into substantial cell throughput gains, up to 200%, compared to 1-hop systems. Despite its low complexity, the RCDD scheme has similar performance to that of other more sophisticated 2-hop schemes such as Relay Alamouti and Relay Coherent Combining. Marginally better results are observed for the Relay Selection Diversity scheme.展开更多
广播电视监测报警是确保安全播出的关键手段。本文从市级广播电视监测中心的视角出发,深入探讨了监测报警容量需求、节点设计及功能实现等问题。基于TS over IP技术,设计了一套多画面监测报警系统,能够对多种类信号的异态视音频码流、...广播电视监测报警是确保安全播出的关键手段。本文从市级广播电视监测中心的视角出发,深入探讨了监测报警容量需求、节点设计及功能实现等问题。基于TS over IP技术,设计了一套多画面监测报警系统,能够对多种类信号的异态视音频码流、信道、链路、设备等进行实时且精准的监测报警。系统通过多屏多画面和动态音柱等方式进行直观呈现,并依据捕获的异态报警信息,第一时间进行研判和调度处置。展开更多
为了提高风电并网系统暂态功角稳定性,以双馈风力发电机(doubly fed induction generator, DFIG)并联超导储能(superconducting magnetic energy storage, SMES)装置为研究对象,提出了一种联合SMES-DFIG的控制方法。通过风电场接入对系...为了提高风电并网系统暂态功角稳定性,以双馈风力发电机(doubly fed induction generator, DFIG)并联超导储能(superconducting magnetic energy storage, SMES)装置为研究对象,提出了一种联合SMES-DFIG的控制方法。通过风电场接入对系统节点导纳矩阵的修正和收缩处理,并基于拓展等面积等则,依据接入DFIG的网络拓扑和暂态期间系统等值功角变化的信息,分析系统等值机械功率改变量的增减性质对系统功角的影响关系,对与DFIG并联的SMES给出了提高系统暂态功角稳定性的功率输出综合控制规律,并对控制策略的有效性进行了仿真验证。研究结果表明,合理准确地控制SMES的功率输出可以改善系统等值功角的变化,加快系统稳定的恢复速度,该研究结果可为利用SMES提高多机系统暂态稳定性的控制提供参考。展开更多
文摘This paper presents the derivation of an analytical model for a multi-queue nodes network router, which is referred to as the multi-queue nodes （mQN） model. In this model, expressions are derived to calculate two performance metrics, namely, the queue node and system utilization factors. In order to demonstrate the flexibility and effectiveness of the mQN model in analyzing the performance of an mQN network router, two scenarios are performed. These scenarios investigated the variation of queue nodes and system utilization factors against queue nodes dropping probability for various system sizes and packets arrival routing probabilities. The performed scenarios demonstrated that the mQN analytical model is more flexible and effective when compared with experimental tests and computer simulations in assessing the performance of an mQN network router.
文摘In this paper, distributed relay diversity systems are analyzed, modeled and evaluated in an Orthogonal Frequency Division Multiplexing (OFDM) based networks. The investigated distributed relay diversity schemes extend the ideas of a single hop transmit antenna schemes such as Cyclic Delay Diversity (CDD), Space Time Transmit Diversity (STTD), transmit Coherent Combining (CC) and Selection Diversity (SD) to distributed diversity systems. In contrast to the classical single hop system, the antennas in the distributed systems belongs to distributed relays instead of being co-located at the transmitter. The distributed relay diversity methods considered in this paper: Relay CDD (RCDD), Relay Alamouti (i.e.STTD), Relay CC (RCC) and Relay SD (RSD) are compared to the traditional 1-hop system. Analytical expressions for the received Signal to Interference Noise Ratio (SINR) are derived and used in a dynamic multi-cell multi-user simulator. Results show considerable SINR gains for both Round Robin and Max-SINR schedulers. The SINR gains translate into substantial cell throughput gains, up to 200%, compared to 1-hop systems. Despite its low complexity, the RCDD scheme has similar performance to that of other more sophisticated 2-hop schemes such as Relay Alamouti and Relay Coherent Combining. Marginally better results are observed for the Relay Selection Diversity scheme.
文摘广播电视监测报警是确保安全播出的关键手段。本文从市级广播电视监测中心的视角出发,深入探讨了监测报警容量需求、节点设计及功能实现等问题。基于TS over IP技术,设计了一套多画面监测报警系统,能够对多种类信号的异态视音频码流、信道、链路、设备等进行实时且精准的监测报警。系统通过多屏多画面和动态音柱等方式进行直观呈现,并依据捕获的异态报警信息,第一时间进行研判和调度处置。
文摘为了提高风电并网系统暂态功角稳定性,以双馈风力发电机(doubly fed induction generator, DFIG)并联超导储能(superconducting magnetic energy storage, SMES)装置为研究对象,提出了一种联合SMES-DFIG的控制方法。通过风电场接入对系统节点导纳矩阵的修正和收缩处理,并基于拓展等面积等则,依据接入DFIG的网络拓扑和暂态期间系统等值功角变化的信息,分析系统等值机械功率改变量的增减性质对系统功角的影响关系,对与DFIG并联的SMES给出了提高系统暂态功角稳定性的功率输出综合控制规律,并对控制策略的有效性进行了仿真验证。研究结果表明,合理准确地控制SMES的功率输出可以改善系统等值功角的变化,加快系统稳定的恢复速度,该研究结果可为利用SMES提高多机系统暂态稳定性的控制提供参考。
