Testing for Year 2000 readiness: technical and management issues

The approach of the Year 2000 (Y2K) has called into question the condition of readiness of computer systems upon which organizations depend. Will these systems operate reliably after midnight, January 1, 2000, or will problems associated with date calculations cause failures that adversely affect users? This question has caused organizations to identify their critical systems, test these systems for Y2K problems, and take corrective action where necessary to ensure Y2K readiness. This paper examines various technical and management issues that Southwest Research Institute has dealt with in solving these problems     

Analysis and results of the 1995 Yuma ground penetration SARmeasurements

In July and October 1995, a large-scale airborne SAR experiment was conducted in the Yuma Proving Ground, Yuma, Arizona, to investigate ground penetration radar phenomenology and buried target detection. This paper describes the Yuma experiment and measurement results for many tactical, utility, and environmental targets deployed in the test     

Multiparametric importance sampling for simulation of radar systems

The performances of the importance sampling (IS) techniques are improved by using multiparametric distortions of the input random processes. The analysis of different constant false-alarm rate (CFAR) algorithms confirms the usefulness of this method. The potential of this new approach is fully exploited if optimization techniques are used to obtain the optimum distortions and to avoid bias in the estimates     

Independent validation and verification of the TCAS II collisionavoidance subsystem

This paper describes the specification-based testing, analysis tools, and associated processes used to independently validate, verify, and ultimately, provide for certifying safety-critical software developed for the Traffic Alert and Collision Avoidance System (TCAS II) program. These tools and processes comprise an effective and Independent Validation and Verification (IV and V) activity applied to the Collision Avoidance Subsystem (GAS) software development process. A requirements specification language called the Requirements State Machine Language (RSML), originally developed by the University of California, Irvine (UCI), was employed for the specification of GAS. The end result is the next generation of TCAS II collision avoidance logic, referred to as Version 7, that is of a higher quality than its predecessors, meets the certification requirements of DO-178B Level B (Ref. 1), and can be shown to satisfy the new operational requirements it was developed to address     

Large-scale Coronal Heating, Clustering of Coronal Bright Points, and Concentration of Magnetic Flux

By combining quiet-region Fe XII coronal images from SOHO/EIT with magnetograms from NSO/Kitt Peak and from SOHO/MDI, we show that the population of network coronal bright points and the magnetic flux content of the network are both markedly greater under the bright half of the large-scale quiet corona than under the dim half. These results (1) support the view that the heating of the entire corona in quiet regions and coronal holes is driven by fine-scale magnetic activity (microflares, explosive events, spicules) seated low in the magnetic network, and (2) suggest that this large-scale modulation of the magnetic flux and coronal heating is a signature of giant convection cells. This revised version was published online in June 2006 with corrections to the Cover Date.