Non-intrusive parameter identification procedure user's guide

Written in standard FORTRAN, NAS is capable of identifying linear as well as nonlinear relations between input and output parameters; the only restriction is that the input/output relation be linear with respect to the unknown coefficients of the estimation equations. The output of the identification algorithm can be specified to be in either the time domain (i.e., the estimation equation coefficients) or in the frequency domain (i.e., a frequency response of the estimation equation). The frame length ("window") over which the identification procedure is to take place can be specified to be any portion of the input time history, thereby allowing the freedom to start and stop the identification procedure within a time history. There also is an option which allows a sliding window, which gives a moving average over the time history. The NAS software also includes the ability to identify several assumed solutions simultaneously for the same or different input data

EXPERIMENTAL AND CALCULATED RESULTS OF A FLUTTER INVESTIGATION OF SOME VERY LOW ASPECT-RATIO FLAT-PLATE SURFACES AT MACH NUMBERS FROM 0.62 TO 3.00

Flutter investigation of very low aspect-ratio flat-plate surfaces at subsonic and supersonic spee

Romania's evolving legal framework for private sector development

As the economies of Central and Eastern Europe move from central planning and state ownership to market-driven development of private sector activity, they are undertaking comprehensive change in the"rules of the game", the legal framework for economic activity. The authors analyze the evolving legal framework for private sector development in Romania. The government has worked intensively in the last two years to create a legal framework for a market economy. It has adopted not only a new constitution but also extensive new legislation covering real and intellectual property, companies, and foreign investment. It has revived the pre-war civil code as a basis for contract law, and is moving to modernize its bankruptcy code. The only area surveyed in which little legal reform has occurred is antimonopoly law. Challenges remain in both law and practice. The broad principles of private ownership, free market exchange, and equal treatment of public and private firms are well recognized and have been largely achieved. But a tendency towards centralized, bureaucratic control remains in excessive requirements for approval and uneconomic limits on certain activities. Moreover, implementation will take a long time because there is little or no institutional framework for enforcement and dispute resolution. Developing a body of regulation and case practice will take time.Environmental Economics&Policies,National Governance,Legal Products,Banks&Banking Reform,Real&Intellectual Property Law

Experimental and Analytical Investigation of the Transonic and Supersonic Divergence Characteristics of a Delta-Plan-Form All- Movable Control

The static aeroelastic divergence characteristics of a delta-planform model of the canard control surface of a proposed air-to-ground missile have been studied both analytically and experimentally in the Mach number range from 0.6 to 3.0. The experiments indicated that divergence occurred at a nearly constant value of dynamic pressure at Mach numbers up to 1.2. At higher Mach numbers somewhat higher values of dynamic pressure were required to produce divergence. The analysis and the experiment indicate that the camber stiffness of the control surface and the stiffness of the control actuator are both important in divergence of surfaces of this type

Analysis of pilot control strategy

Methods for nonintrusive identification of pilot control strategy and task execution dynamics are presented along with examples based on flight data. The specific analysis technique is Nonintrusive Parameter Identification Procedure (NIPIP), which is described in a companion user's guide (NASA CR-170398). Quantification of pilot control strategy and task execution dynamics is discussed in general terms followed by a more detailed description of how NIPIP can be applied. The examples are based on flight data obtained from the NASA F-8 digital fly by wire airplane. These examples involve various piloting tasks and control axes as well as a demonstration of how the dynamics of the aircraft itself are identified using NIPIP. Application of NIPIP to the AFTI/F-16 flight test program is discussed. Recommendations are made for flight test applications in general and refinement of NIPIP to include interactive computer graphics

Editor\u27s Corner

From the Outgoing Managing Editor: The start of 1985 signals the transfer of the last vestiges of my former position as executive director of the Academy to Jim Macmillan, who now takes on the role of managing editor of Academy publications