An inspector calls [nondestructive testing]

Composite laminate structures offer many advantages compared with their conventional metal counterparts, but defects can be much harder to detect. In this paper, the author describes how neural networks provide the key to a new, intelligent technique for nondestructive testing     

Tighter controls for busier systems [power systems]

A variety of new technologies are becoming available that will help utilities maintain power system reliability while handling the larger volume of transactions. For example, power electronic systems can provide unprecedented control over electricity flow on transmission networks, preventing or containing cascading disturbances. In addition, new sensor technology, faster communications between control centers, and advanced software tools can enable utilities to monitor system conditions in real time, letting them respond more quickly to disturbances and minimize their impact. Over the next decade, these technologies will facilitate increased power transfers through power delivery systems that are presently constrained, providing power at lower cost to a greater number of customers. It is a question of how to optimize power flow through an entire network by integrating multiple technologies and coordinating control over wide areas. Such integration and coordination will be necessary for deregulation to proceed smoothly toward its twin goals: reducing electricity costs to US consumers, while maintaining the high levels of reliability they have come to expect. The authors discuss the following technologies to help achieve these goals including: flexible AC transmission systems (FACTS), the next generation of FACTS controllers, hierarchical control of FACTS, on-line power systems analysis, control centre communications, and wide area measurement system     

Instrumentation for gathering data [DAQ systems]

The main characteristic of the intelligent distributed data acquisition system we describe in this article is that it supports intelligent functions and provides the desired accuracy of measurement. It is also reliable and adaptable, utilising two NN-based methods of sensor drift prediction, which allows it to increase its inter-testing interval, and provides accuracy of sensor data processing. The system is designed on a distributed intelligence scheme, which operates in real time for most industrial sensors.     

An automated field repair tracking system [telecommunicationproducts]

The purpose of repair tracking (RT) is to provide ongoing feedback of product reliability performance in the customer environment. The authors present an RT technique and provide an overview of its automated software implementation, which has been used to track several transmission system products. The RT implementation, referred to as the repair equipment analysis program (REAP), tracks the field performance of electronic equipment at system, subsystem, circuit pack, and component levels. The features of REAP include monthly reliability performance reports, alarms when degradation in performance is detected, model sensitivity analysis, problem areas isolation for initiating corrective actions, and specific customer performance studies. The approach encompasses the entire population during the product life using existing sales and repair data as main inputs. Further, it does not require customer involvement or product serialization     

Parameter trade-offs for imaging spectroscopy systems [remotesensing]

To help better understand the problems of specifying data acquisition parameters and extracting desired information from the voluminous data, research has been focused on understanding the remote sensing process as a system and investigating the interrelated effects of various parameters. A system model is used to explore system parameter trade-offs for a model sensor based on the High-Resolution Imaging Spectrometer (HIRIS). Radiometric performance was studied, along with the effect on classification accuracy of several system parameters. The atmosphere and sensor have significant effects on the mean received signal and noise performance. The effect of random uncorrelated errors in the radiometric calibration of the detector array is discussed. Accurate pixel-to-pixel relative radiometric calibration and the use of the image motion compensation (IMC) option are seen to improve classification accuracy. The selection of feature sets based on combining spectral bands was studied under a variety of observational conditions     

Large jobs for little devices [microelectromechanical systems]

Microelectromechanical systems (MEMS) may become key components of radio frequency devices, particularly in the mobile marketplace. In filters, they may lower radio size and power consumption while increasing sensitivity. In switches, they could herald the construction of cheaper, electronically steerable antennas for radar and communications applications. MEMS are electromechanical devices with tiny moving parts. They can be built using IC-compatible materials, such as polysilicon, allowing their integration on a silicon chip, side-by-side with semiconductor circuits. Experimental filters are now reaching hundreds of megahertz, and operation up in the gigahertz ranges needed for most wireless and some satellite communications should be feasible. Their ability to kill several birds with one stone is making them very attractive to researchers and developers     

Computer-assisted applications [telephone systems]

Capabilities of computer-to-telephone system linkages are discussed. The intelligent answering, coordinated voice/data transfer, preview dialing, and predictive dialing features of computer-assisted telephone systems are described. The CallPath Services Architecture, which provides an application program interface that masks out the differences between telephone systems, is also discussed     

Earthquake [earthquake warning systems]

Accurate earthquake warnings are, at last, within reach. Instead of coming from the mechanical phenomena that have been the focus of decades of study, however, they will come from electromagnetic phenomena. And, remarkably, these predictions will come from signals gathered not only at the earth's surface but also in the ionosphere. It has been observed that electromagnetic disturbances happen during the days that precede an earthquake. These disturbances happen when crystalline rocks are deformed by the slow grinding of the earth that occurs just before an earthquake. The cracking creates tremendous electric currents in the ground, which travel to the surface and into the air. These currents alter the magnetic field surrounding the earthquake zone and these electromagnetic effects can easily be detected. While such an earthquake warning system would be useful, there are a number of technical and financial problems that need first to be addressed before they can be installed worldwide.     

Novel adaptive IIR filter for frequency estimation and tracking [DSP Tips&Tricks]

In many applications, a sinusoidal signal may be subjected to nonlinear effects in which possible harmonic frequency components are generated. In such an environment we may want to estimate (track) the signal's fundamental frequency as well as any harmonic frequencies. Using a second-order notch filter to estimate fundamental and harmonic frequencies is insufficient since it only accommodates one frequency component [1], [2]. On the other hand, applying a higherorder IIR notch filter may not be efficient due to adopting multiple adaptive filter coefficients.     

The millennium bug [computer systems]

There is a time bomb ticking away within the world's computers. Come the next millennium and many computer systems will, quite literally, not know what year it is. Here, the author describes the origins of this problem and suggests some solutions     

Clear skies ahead [navigation systems]

Several projects aimed squarely at upgrading airplane travel, either by enhancing navigation or by improving communications between pilots and air traffic controllers, drew closer to full implementation in 2001. In mid-June, the US Federal Aviation Administration (FAA), Washington, DC, outlined its 10-year operational evolution plan to improve air travel by rolling out new technology to air traffic control facilities. All the systemwide projects target congestion in the skies and on the runways. For too long a time, too many airports were scheduling too many takeoffs or landings for any given period, driving the numbers of delays up. After 11 September, safer air travel became the burning issue. But congestion will no doubt return to prominence once airlines resume full schedules. Meantime, the global positioning system (GPS) satellite constellation and improved situational awareness tools are beginning to enhance safety now, and will alleviate congestion when it returns     

Field tracking studies: theory and practice [electronic equipmentpopulation]

Field tracking is a controlled study of a population of electronic equipment under field operating conditions. A field tracking study (FTS) is primarily used to evaluate product reliability performance in order to verify product conformance to reliability objectives and requirements. The planning, implementation, and analysis of FTSs are described with reference to practical experience with tracking studies on numerous digital transmission systems