In past, dependable networks meant minimizing network outages or the impact of the outages. However, over the decade, major network services have shifted from telephone and data transmission to Internet and to mobile communication, where higher layer services with a variety of contents are provided. Reviewing these backgrounds of network development, the importance of the dependability of highe...

Establishing the current road type constitutes a significant assistance to car drivers, as, by default, determines legal speed limit. Although there are GPS- and map-based navigation systems that can retrieve actual limit some even access indicate traffic volumes, it was our aim develop test software prototype of road-type detection (RTD) system relies solely on video sensor data collected boar...

The change in the loading margin to voltage collapse when line outages occur is estimated. First a nose curve is computed by continuation to obtain a nominal loading margin. Then linear and quadratic sensitivities of the loading margin to each contingency are computed and used to estimate the resulting change in the loading margin. The method is tested on a critical area of a 1390 bus system an...

The technical infrastructure is of crucial importance for modern society and electric power supplies are of particular importance. Society's dependence on electrical energy, communications and information technology is increasing. At the same time users, both industry and households, have overconfidence in technical infrastructure functionality and little preparedness for outages in the power n...

Large blackouts typically involve the cascading outage of transmission lines. However, little is known about the overall patterns of cascading outages. This research processes and initially examines observed utility data to explore the spatial spreading of cascading failure. The utility data is combined from two different sources, one year of recorded transmission line outages and a description...

although i have Managed the innovation coluMn continuously since GPS World’s first issue, it wasn’t until the second issue that I authored a column article. That article, co-written with Alfred Kleusberg, was titled “The Limitations of GPS.” It discussed some of the then-current problems of GPS, including poor signal reception, loss of signal integrity, and limited positioning accuracy. In the ...

Power grids exhibit patterns of reaction to outages similar to complex networks. Blackout sequences follow power laws, as complex systems operating near a critical point. Here, the tolerance of electric power grids to both accidental and malicious outages is analyzed in the framework of complex network theory. In particular, the quantity known as efficiency is modified by introducing a new conc...

We study the dependence on fiber birefringence of the bit-error rate (BER) caused by amplifier noise in a linear optical fiber telecommunication system. We show that the probability-distribution function of the BER obtained by averaging over many realizations of birefringent disorder has an extended tail that corresponds to anomalously large values of BER. We specifically discuss the dependence...