In-flight simulation investigation of rotorcraft pitch-roll cross coupling

An in-flight simulation experiment investigating the handling qualities effects of the pitch-roll cross-coupling characteristic of single-main-rotor helicopters is described. The experiment was conducted using the NASA/Army CH-47B variable stability helicopter with an explicit-model-following control system. The research is an extension of an earlier ground-based investigation conducted on the NASA Ames Research Center's Vertical Motion Simulator. The model developed for the experiment is for an unaugmented helicopter with cross-coupling implemented using physical rotor parameters. The details of converting the model from the simulation to use in flight are described. A frequency-domain comparison of the model and actual aircraft responses showing the fidelity of the in-flight simulation is described. The evaluation task was representative of nap-of-the-Earth maneuvering flight. The results indicate that task demands are important in determining allowable levels of coupling. In addition, on-axis damping characteristics influence the frequency-dependent characteristics of coupling and affect the handling qualities. Pilot technique, in terms of learned control crossfeeds, can improve performance and lower workload for particular types of coupling. The results obtained in flight corroborated the simulation results

Audit of burns patients in the intensive care setting [poster]

No abstract available

How Precise are Estimates of the Natural Rate of Unemployment?

This paper investigates the precision of conventional and unconventional estimates of the natural rate of unemployment (the 'NAIRU'). The main finding is that the NAIRU is imprecisely estimated: a typical 95% confidence interval for the NAIRU in 1990 is 5.1% to 7.7%. This imprecision obtains whether the natural rate is modeled as a constant, as a slowly changing function of time, as an unobserved random walk, or as a function of various labor market fundamentals; it obtains using other series for unemployment and inflation, including additional supply shift variables in the Phillips curve, using monthly or quarterly data, and using various measures for expected inflation. This imprecision suggests caution in using the NAIRU to guide monetary policy.

Cross-cultural interpretations of fraud: An attitudinal study in a Middle Eastern multinational corporation

This research tested the theory that cultural heritage affects attitudes toward business-related fraud and, as a consequence, influences ethical decisions. A sample of 695 white-collar employees from a Middle Eastern multinational corporation (MNC), who represented nine world cultures, were asked to evaluate scenarios describing five business frauds--bribery, conflict of interest, embezzlement, management fraud, and industrial espionage--against a 7-point Likert-type scale that measured levels of approval. Analysis of variance (ANOVA) of the responses revealed those claiming African, Caribbean/South American, European, Middle Eastern, and North American cultural heritage viewed fraudulent behavior with a greater degree of disapproval than did those claiming Asian, Australian/New Zealander, Mediterranean, and Pacific Islander cultural heritage. However, while cultures had dissimilar attitudes to fraud in general, the respondents\u27 attitudes about specific frauds were statistically equivalent when each fraud was individually assessed. In other words, some cultures espoused a less tolerant ethical standard about fraud, but when a particular type of fraud was isolated for personal evaluation, these employees disapproved of the scenarios with relative equality, regardless of their cultural heritage. When traditional variables of age, education, gender, and occupation were analyzed, only age revealed significant differentiation. Finally, comparative analysis of the data revealed that in a multicultural business environment, espoused ethical standards are assimilated by the majority, cultural heritage is diffused, and a corporate culture phenomenon influences attitude formation to ethical dilemmas. Using these results, MNC managers could introduce a focused fraud awareness program to increase their employees\u27 knowledge base about fraud, resulting in greater recognition of deviant conduct, thereby decreasing the potential for undesirable behavior across cultures while simultaneously providing a multicultural approach to solving ethical dilemmas