En route position and time control of aircraft using Kalman filtering of radio aid data

Fixed-time-of-arrival (FTA) guidance and navigation is investigated as a possible technique capable of operation within much more stringent en route separation standards and offering significant advantages in safety, higher traffic densities, and improved scheduling reliability, both en route and in the terminal areas. This study investigated the application of FTA guidance previously used in spacecraft guidance. These FTA guidance techniques have been modified and are employed to compute the velocity corrections necessary to return an aircraft to a specified great-circle reference path in order to exercise en route time and position control throughout the entire flight. The necessary position and velocity estimates to accomplish this task are provided by Kalman filtering of data from Loran-C, VORTAC/TACAN, Doppler radar, radio or barometric altitude,and altitude rate. The guidance and navigation system was evaluated using a digital simulation of the cruise phase of supersonic and subsonic flights between San Francisco and New York City, and between New York City and London

From Baking a Cake to Solving the Schrodinger Equation

The primary emphasis of this study has been to explain how modifying a cake recipe by changing either the dimensions of the cake or the amount of cake batter alters the baking time. Restricting our consideration to the genoise, one of the basic cakes of classic French cuisine, we have obtained a semi-empirical formula for its baking time as a function of oven temperature, initial temperature of the cake batter, and dimensions of the unbaked cake. The formula, which is based on the Diffusion equation, has three adjustable parameters whose values are estimated from data obtained by baking genoises in cylindrical pans of various diameters. The resulting formula for the baking time exhibits the scaling behavior typical of diffusion processes, i.e. the baking time is proportional to the (characteristic length scale)^2 of the cake. It also takes account of evaporation of moisture at the top surface of the cake, which appears to be a dominant factor affecting the baking time of a cake. In solving this problem we have obtained solutions of the Diffusion equation which are interpreted naturally and straightforwardly in the context of heat transfer; however, when interpreted in the context of the Schrodinger equation, they are somewhat peculiar. The solutions describe a system whose mass assumes different values in two different regions of space. Furthermore, the solutions exhibit characteristics similar to the evanescent modes associated with light waves propagating in a wave guide. When we consider the Schrodinger equation as a non-relativistic limit of the Klein-Gordon equation so that it includes a mass term, these are no longer solutions.Comment: 23 pages, 10 Postscript figure

A NASTRAN primer for the analysis of rotating flexible blades

This primer provides documentation for using MSC NASTRAN in analyzing rotating flexible blades. The analysis of these blades includes geometrically nonlinear (large displacement) analysis under centrifugal loading, and frequency and mode shape (normal modes) determination. The geometrically nonlinear analysis using NASTRAN Solution sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. A sample problem with the complete NASTRAN input data is included. Items unique to rotating blade analyses, such as setting angle and centrifugal softening effects are emphasized

Multiple Maltreatment, Attribution Of Blame, And Adjustment Among Adolescents

The present study had two purposes. First, it examined the combined and unique contribution of five maltreatment types to variance in adolescent adjustment (i.e., physical abuse, sexual abuse, emotional abuse, neglect and exposure to family violence). In accordance with contemporary social learning theory (social cognitive theory), it was hypothesized that aggressive forms of maltreatment would predict externalizing problems, particularly for boys, whereas nonaggressive maltreatment would predict internalizing problems. Second, the study examined the predictive utility of blame attributions for maltreatment. Integrating the writings of several theorists regarding blame attribution, it was predicted that self-blame would mediate or moderate internalizing problems, whereas other-blame would mediate or moderate externalizing problems. Mediator and moderator models were tested separately.;Adolescents (N = 160, aged 11-17) were randomly selected from the open caseload of a child protection agency. Subjects made global severity ratings regarding their experiences of the five types of maltreatment. Similar ratings were made for each subject by the adolescent\u27s social worker and by trained raters of case files. Subjects also completed the Attribution for Maltreatment Interview (AFMI) to assess self- and perpetrator-blame for each type of maltreatment they experienced. Subjects also completed a battery of measures assessing self- and caretaker-reported externalizing and internalizing symptomatology.;Discrepancies in maltreatment occurrence and severity judgements were found between adolescents and professionals. Adolescent maltreatment ratings significantly predicted self-reported adjustment, even when controlling for sex, age, SES, receptive vocabulary, and stressful life events. Emotional abuse was the most predictively potent maltreatment type, and enhanced the predictive utility of other maltreatment types.;The AFMI yielded five subscales: self-blaming cognition, self-blaming affect, self-excusing, perpetrator-blame, and perpetrator-excusing. Controlling for maltreatment severity, these subscales explained significant variance in self-reported adjustment. Self-blaming affect was the most potent, particularly among females. Attributions were found to both mediate and moderate maltreatment severity.;The findings were consistent with recent developments in social learning theory. They illustrated that victims\u27 subjective appraisals of maltreatment are important to adjustment. The sophistication of blame attribution processes among victims was underscored. Implications for theory, measurement, and clinical practice are discussed

Visitor Attitudes and Perceptions on Vegetation Management along the Blue Ridge Parkway

Vegetation management practices along a scenic parkway may be very costly. A finely manicured appearance requires regular mowing and trimming while a less manicured appearance requires less maintenance. Many benefits that recreation visitors receive are directly related to how the visual environment is managed and presented (Hammitt 1980; Mercer 1975; Moeller et al. 1974). Driving for pleasure and sightseeing depend greatly on perception of the visual environment. By learning how visitors perceive vegetation management practices along a scenic parkway, natural resource managers could identify preferred scenes and possibly modify some management practices. These modifications could help reduce maintenance costs while making parkways more attractive to visitors. This study was designed to determine visitor attitudes and preferences on vegetation management practices and alternatives along the Blue Ridge Parkway. Photographs were used in a questionnaire to represent various types of vegetation management. The photos were used as the stimuli for visitors to recall similar vegetation scenes along the Parkway and to present simulations of other possible vegetation management techniques and alternatives. The study used an information treatment as a first page in one-half of the questionnaires. The treatment was used to determine whether or not information can make a significant difference in visitor attitudes and preferences toward vegetation management practices. The treatment combined an environmental message and a statement of money savings to tax payers through less intensive vegetation management. Survey questionnaires were given to 600 Blue Ridge Parkway visitors during the summer of 1982. The questionnaire presented vegetation management practices by using pairs of photos with a brief clarifying statement below each photo. The scenes depicted different levels of vegetation management at overlook vistas and along roadsides. Visitors indicated the preference for each photo as compared to its pair (on a Likert scale). The questionnaire also contained twelve vegetation management alternative statements. These statements were designed to obtain respondent attitudes on practices related but not identical to those depicted in the photos. Data were analyzed for preferences of photographs, attitudes on vegetation management statements, and the effect of the information treatment. Results indicated that roadside scenes with less mowing were highly preferred. Vista overlooks were preferred with some low foreground and middleground vegetation within the photograph. Scenes containing wildflowers were highly preferred while roadsides with no mowing and vistas with over 50% of the view blocked were the least preferred. Attitudes on the vegetation management statements paralleled the photo preferences closely. The information treatment used appeared to be effective on respondent attitudes and preferences on only a few roadside mowing scenes

Helical automatic approaches of helicopters with microwave landing systems

A program is under way to develop a data base for establishing navigation and guidance concepts for all-weather operation of rotorcraft. One of the objectives is to examine the feasibility of conducting simultaneous rotorcraft and conventional fixed-wing, noninterfering, landing operations in instrument meteorological conditions at airports equipped with microwave landing systems (MLSs) for fixed-wing traffic. An initial test program to investigate the feasibility of conducting automatic helical approaches was completed, using the MLS at Crows Landing near Ames. These tests were flown on board a UH-1H helicopter equipped with a digital automatic landing system. A total of 48 automatic approaches and landings were flown along a two-turn helical descent, tangent to the centerline of the MLS-equipped runway to determine helical light performance and to provide a data base for comparison with future flights for which the helical approach path will be located near the edge of the MLS coverage. In addition, 13 straight-in approaches were conducted. The performance with varying levels of state-estimation system sophistication was evaluated as part of the flight tests. The results indicate that helical approaches to MLS-equipped runways are feasible for rotorcraft and that the best position accuracy was obtained using the Kalman-filter state-estimation with inertial navigation systems sensors