为了提高复杂电网故障监测的精度和可靠性,采用电气量和开关量数据对电网故障进行监测。通过故障信息系统获得电流信号数据,对获得的电流信号数据进行小波变换得到小波故障度、小波奇异度和小波能量度,同时通过SCADA(Supervisory Contro...为了提高复杂电网故障监测的精度和可靠性,采用电气量和开关量数据对电网故障进行监测。通过故障信息系统获得电流信号数据,对获得的电流信号数据进行小波变换得到小波故障度、小波奇异度和小波能量度,同时通过SCADA(Supervisory Control And Data Acquisition)系统获得开关量数据,通过搭建Petri网模型得到模糊故障度。采用D-S证据理论将多源数据进行融合,最终达到对复杂电网故障监测的目的。以河南省某局部电网系统为例,采用电气量和开关量数据进行电网故障监测,结果表明该方法能够有效提高复杂电网故障监测的精度,具有一定的工程应用价值。展开更多
In a developing country, modernization and change of the accounting regime are possible if the standards are in compliance with global ones. The change of accounting standards adopted by Turkey started to be implement...In a developing country, modernization and change of the accounting regime are possible if the standards are in compliance with global ones. The change of accounting standards adopted by Turkey started to be implemented, and this created a number of qualitative and quantitative results. This study examines the impact of change of accounting standards on accounting quality. In order to determine how switching standard reflects accounting quality, first of all, the earnings management, timely loss recognition, and value relevance variables pertaining to accounting quality were listed and the findings were stated after subjecting the obtained data to statistical analyses. Accordingly, by the transition to International Financial Reporting Standards （IFRS）, the earnings management practices were observed to decrease as compared with the pre-IFRS period and the timely loss recognition and value-relevance values were observed to increase, which constitute the dimensions of accounting quality. It was also concluded that by the switch from domestic accounting standards to International Accounting Standards （IAS）, the quality of accounting in the country was improved and the market became more active than it was before.展开更多
Software Defined Networking （SDN） is an emerging networking paradigm that assumes a logically centralized control plane separated from the data plane. Despite all its advantages, separating the control and data plan...Software Defined Networking （SDN） is an emerging networking paradigm that assumes a logically centralized control plane separated from the data plane. Despite all its advantages, separating the control and data planes introduces new challenges regarding resilient communications between the two. That is, disconnec- tions between switches and their controllers could result in substantial packet loss and performance degradation. This paper addresses this challenge by studying the issue of control traffic protection in SDNs with arbitrary numbers of controllers. Specifically, we propose a control traffic protection scheme that combines both local rerouting and constrained reverse path forwarding protections, through which switches can locally react to fail- ures and redirect the control traffic using standby backup forwarding options. Our goal is then to find a set of primary routes for control traffic, called protected control network, where as many switches as possible can benefit from the proposed protection scheme. We formulate the protected control network problem, prove its NP-hardness, and develop an algorithm that reconciles proteetability and performance （e.g., switch-to-control latency）. Through extensive simulations based on real topologies, we show that our approach significantly im- proves protectability of control traffic. The results should help further the process of deploying SDN in real-world networks.展开更多
文摘为了提高复杂电网故障监测的精度和可靠性,采用电气量和开关量数据对电网故障进行监测。通过故障信息系统获得电流信号数据,对获得的电流信号数据进行小波变换得到小波故障度、小波奇异度和小波能量度,同时通过SCADA(Supervisory Control And Data Acquisition)系统获得开关量数据,通过搭建Petri网模型得到模糊故障度。采用D-S证据理论将多源数据进行融合,最终达到对复杂电网故障监测的目的。以河南省某局部电网系统为例,采用电气量和开关量数据进行电网故障监测,结果表明该方法能够有效提高复杂电网故障监测的精度,具有一定的工程应用价值。
文摘In a developing country, modernization and change of the accounting regime are possible if the standards are in compliance with global ones. The change of accounting standards adopted by Turkey started to be implemented, and this created a number of qualitative and quantitative results. This study examines the impact of change of accounting standards on accounting quality. In order to determine how switching standard reflects accounting quality, first of all, the earnings management, timely loss recognition, and value relevance variables pertaining to accounting quality were listed and the findings were stated after subjecting the obtained data to statistical analyses. Accordingly, by the transition to International Financial Reporting Standards （IFRS）, the earnings management practices were observed to decrease as compared with the pre-IFRS period and the timely loss recognition and value-relevance values were observed to increase, which constitute the dimensions of accounting quality. It was also concluded that by the switch from domestic accounting standards to International Accounting Standards （IAS）, the quality of accounting in the country was improved and the market became more active than it was before.
基金supported in part by National High-tech R&D Program of China(863 Program)(Grant Nos.2013AA0133012015AA016101)
文摘Software Defined Networking （SDN） is an emerging networking paradigm that assumes a logically centralized control plane separated from the data plane. Despite all its advantages, separating the control and data planes introduces new challenges regarding resilient communications between the two. That is, disconnec- tions between switches and their controllers could result in substantial packet loss and performance degradation. This paper addresses this challenge by studying the issue of control traffic protection in SDNs with arbitrary numbers of controllers. Specifically, we propose a control traffic protection scheme that combines both local rerouting and constrained reverse path forwarding protections, through which switches can locally react to fail- ures and redirect the control traffic using standby backup forwarding options. Our goal is then to find a set of primary routes for control traffic, called protected control network, where as many switches as possible can benefit from the proposed protection scheme. We formulate the protected control network problem, prove its NP-hardness, and develop an algorithm that reconciles proteetability and performance （e.g., switch-to-control latency）. Through extensive simulations based on real topologies, we show that our approach significantly im- proves protectability of control traffic. The results should help further the process of deploying SDN in real-world networks.
