The earth’s ionosphere can cause serious problems for many radio applications: DOD C31 and navigation systems and commercial applications such as communications, radio astronomy and navigation. They can all be seriously affected by ionospheric disturbances. Disturbance effects such as amplitude fading and phase scintillation limit the ability to coherently integrate weak signals. One solution, ...

The wide application of Global Positioning System (GPS) carrier-phase (CP) time transfer is limited by the problem of boundary discontinuity (BD). The discontinuity has two categories. One is "day boundary discontinuity," which has been studied extensively and can be solved by multiple methods [1-8]. The other category of discontinuity, called "anomaly boundary discontinuity (anomaly-BD)," come...

ue to the expansion of power systems there is a challenge of real time monitoring and control by placing important parameters at various points for efficient functioning of the power system. There can be drastic changes during hourly load fluctuations, component outages, or network switching. In such conditions, the inclusion of predicted values could degrade the power system state estimation h...

Tandem computer systems are designed to be single-fault tolerant. This paper takes a census of customer system outages reported to Tandem. The census shows a clear improvement in the reliability of hardware and maintenance. It indicates that now (1989) software is the majority source of reported system outages (62%), followed by system operations (15%). This is a dramatic shift from the statist...

Background Extreme events (e.g. flooding) threaten critical infrastructure including power supplies. Many interlinked systems in the modern world depend on a reliable power supply to function effectively. The health sector is no exception, but the impact of power outages on health is poorly understood. Greater understanding is essential so that adverse health impacts can be prevented and/or mit...

Many papers have been written on short and medium term scheduling of hydro-electric generation on a river system so as to maximise operating profit. A related area of growing importance is the scheduling of generator maintenance outages to minimise their impact on the profit objective. Historically, the co-ordination of generator outages on a river system has been performed on a "manual" basis ...

Analysis of cascading outages in power systems is important for understanding why large blackouts emerge and how to prevent them. Cascading outages are complex dynamics of power systems, and one cause of them is the interaction between swing dynamics of synchronous machines and protection operation of relays and circuit breakers. This paper uses hybrid dynamical systems as a mathematical model ...

Tandem computer systems are designed to be single-fault tolerant. This paper takes a census of customer system outages reported to Tandem. The census shows a clear improvement in the reliability of hardware and maintenance. It indicates that now (1989) software is the majority source of reported system outages (62%), followed by system operations (15%). This is a dramatic shift from the statist...

Parts of the Internet are down every day, from the intentional shutdown of the Egyptian Internet in Jan. 2011 and natural disasters such as the Mar. 2011 Japanese earthquake, to the thousands of small outages caused by localized accidents, and human error, maintenance, or choices. Understanding these events requires efficient and accurate detection methods, motivating our new system to detect n...