Insensitive control technology development

THe investigation of two insensitive controller synthesis techniques was reported. The finite dimensional inverse approach produces a time varying insensitive controller and/or parameter identifier by constructing inverse functions derived from a finite number of input output pair relationships. The MD/IM concept relies on the information matrix theory that was developed in the estimation and identification field. The MD/IM synthesis technique is based on the hypothesis that minimizing the information matrix will reduce system identifiability and consequently system sensitivity to uncertain parameters. The controllers designed with both techniques were evaluated on a realistic C-5A aircraft flight control problem. Results indicate that the FDI controller is more suited to trajectory type problems because of its time varying nature. The MD/IM controller performed as well as the top-rated controllers of the initial effort and has direct application to aircraft flight control problems

Wealth Mobility: The Missing Element

We consider the problems that may arise when cross sectional data alone are used for inferences about individual welfare, the existence of elites, the possibilities of class boundaries, the openness of a society, etc. We also consider problems with alternative measures of socio-economic position. We then use a sample of 2400 households observed over one or two decade intervals together with data on the population of households at each observation point to examine mobility within the distribution of wealth for an almost closed economy, Utah, 1850-1870. We use information on households to examine those characteristics that contribute to mobility. We find considerable mobility, much apparently stochastic, within quite highly skewed distributions of wealth that also exhibit increasing inequality through time.

Unobservable Family and Individual Contributions to the Distributions ofIncome and Wealth

This paper uses a data set composed of combinations of full brothers, half brothers as well as fathers and sons to measure the effect of common family background on households'income and wealth. While the data is drawn from a nineteenth century population, the intra-class correlation (after the effects of age, occupation, nativity, residence and duration in the economy have been removed) for income ranges from .13 to .18 which is similar to that found in modern samples. Intra-class correlations for wealth are significantly higher (.18 to .35) than those for income. The addition of fathers' observed characteristics to the sweeping regressions reduces the unobserved common background effect shared by brothers by about twenty percent.The intra-class correlations of half brothers were lower than those observed for full brothers though the small differences between the two groups suggest that fathers played a dominant role in the transmission of the common family effect. Unobserved background was decomposed into individual and family effects by a variance components procedure. The individual effect was dominant for income while the family effect was dominant for wealth.

Intergenerational Effects of the Distribution of Income and Wealth: The Utah Experience, 1850-1900

The relationship between the wealth or income of parents and children is an important economic issue in both positive and normative senses. In this paper, we estimate elasticities of sons' income or wealth with respect to the wealth of their fathers for a sample of households in nineteenth century Utah. We find the elasticity relating the wealth of fathers to sons to range from .10 to .34 depending on the variables held constant such as occupation, age and residence. Elasticities based on observation of the wealth of fathers and sons in the same year were higher than those based on a lagged value of the fathers' wealth. The death of the father prior to observation of the sons' wealth increased the elasticity about three fold. The elasticity between the income of sons and wealth of fathers was low (.09 to .21) but significant even though the sons' incomes were observed fifteen years after the wealth of fathers. In general, the data suggest a persistent relationship between the economic status of parents and their children with substantial regression toward the mean so that an economic elite was unlikely to be based upon intergenerational transmission of economic success.

Sulfur amino acid requirements of broilers from two to five weeks of age

Phase-feeding (PF) in broiler chickens has been researched as a way to reduce feed costs without reducing growth performance and yield. Predicted amino acid requirements for PF are generated using linear regression equations derived from best estimates of lysine (Lys), sulfur amino acid (SAA), and threonine (Thr) requirements. During the late starter and early grower periods, predicted requirements for the SAA methionine (Met) and cysteine (Cys) are higher than levels recommended by the National Research Council (NRC), and previous research suggests that SAA may be lowered during the grower period without sacrificing growth performance or yield. The objective of this study was to estimate Met and Cys requirements for broilers from 2 to 5 weeks of age. In Experiment 1, a Met-deficient corn-peanut meal diet was formulated to contain excess Cys, so that supplemental Met was not utilized for Cys synthesis. The basal diet for Experiment 2 met the Met requirement but was deficient in Cys. Graded levels of Met (0, 0.045, 0.09, 0.135, and 0.225%) and Cys (0, 0.035, 0.070, 0.105, 0.140, 0.175%) were added in Experiments 1 and 2, respectively, and diets were fed to five replicates of five broilers per pen. Broken-line analysis was used to estimate SAA requirements. The digestible Met and Cys requirements from 2 to 5 weeks of age were 0.33% and 0.31%, respectively. Requirement estimates were lower than those predicted by PF or recommended by NRC, indicating that lower SAA levels may be utilized in a PF progra