881 research outputs found

    Political History of San Juan County

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    San Juan County, the area under consideration, occupies the extreme northwest corner of the state of New Mexico. It is bounded on the north by La Plata County, Colorado, on the west by the state of Arizona, on the south by McKinley County, and on the west by Rio Arriba and Sandoval Counties. This area is something of an empire in itself as it comprises 5,176 square miles, or 3,504,640 acres. Approximately 2,000,000 acres in the area lie within the confines of the Navajo Indian Reservation, leaving some million and a half acres in the county proper, of which about 300,000 are irrigable

    User's manual for interactive LINEAR: A FORTRAN program to derive linear aircraft models

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    An interactive FORTRAN program that provides the user with a powerful and flexible tool for the linearization of aircraft aerodynamic models is documented in this report. The program LINEAR numerically determines a linear system model using nonlinear equations of motion and a user-supplied linear or nonlinear aerodynamic model. The nonlinear equations of motion used are six-degree-of-freedom equations with stationary atmosphere and flat, nonrotating earth assumptions. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model

    Derivation and definition of a linear aircraft model

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    A linear aircraft model for a rigid aircraft of constant mass flying over a flat, nonrotating earth is derived and defined. The derivation makes no assumptions of reference trajectory or vehicle symmetry. The linear system equations are derived and evaluated along a general trajectory and include both aircraft dynamics and observation variables

    Systematic Variation in Willingness to Pay for Agricultural Land Preservation and Implications for Benefit Transfer: A Meta-Analysis

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    Despite prior studies examining willingness to pay for farmland preservation there has been no quantitative, systematic analysis of findings across the literature. This paper presents the first statistical meta-analysis of farmland preservation values. Results confirm systematic variations in willingness to pay, with value surfaces corresponding to theoretical expectations. Findings also provide significant insight into the potential for valid meta-analytic, function based benefit transfer. Results suggest, for example, that transfer validity is critically dependent on jurisdictional scale. Transfer errors are modest for community scale farmland preservation, but large for state scale preservation policies in which per acre welfare estimates are small.Land Economics/Use,

    Application and flight test of linearizing transformations using measurement feedback to the nonlinear control problem

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    The design of nonlinear controllers has relied on the use of detailed aerodynamic and engine models that must be associated with the control law in the flight system implementation. Many of these controllers were applied to vehicle flight path control problems and have attempted to combine both inner- and outer-loop control functions in a single controller. An approach to the nonlinear trajectory control problem is presented. This approach uses linearizing transformations with measurement feedback to eliminate the need for detailed aircraft models in outer-loop control applications. By applying this approach and separating the inner-loop and outer-loop functions two things were achieved: (1) the need for incorporating detailed aerodynamic models in the controller is obviated; and (2) the controller is more easily incorporated into existing aircraft flight control systems. An implementation of the controller is discussed, and this controller is tested on a six degree-of-freedom F-15 simulation and in flight on an F-15 aircraft. Simulation data are presented which validates this approach over a large portion of the F-15 flight envelope. Proof of this concept is provided by flight-test data that closely matches simulation results. Flight-test data are also presented

    Agglomerative Forces and Cluster Shapes

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    We model spatial clusters of similar firms. Our model highlights how agglomerative forces lead to localized, individual connections among firms, while interaction costs generate a defined distance over which attraction forces operate. Overlapping firm interactions yield agglomeration clusters that are much larger than the underlying agglomerative forces themselves. Empirically, we demonstrate that our model's assumptions are present in the structure of technology and labor flows within Silicon Valley and its surrounding areas. Our model further identifies how the lengths over which agglomerative forces operate influence the shapes and sizes of industrial clusters; we confirm these predictions using variations across patent technology clusters

    The Role of Families in Youth Sport Programming in a Canadian Aboriginal Reserve

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    Background: There has been a recent push in the sport psychology literature for sport participants to be approached based on their cultural backgrounds. However, there are few examples where a cultural approach is considered, such as a culturally reflexive version of participatory action research (PAR). In the current study, the role of family is considered in relation to the sport engagement of Canadian Aboriginal youth. Methods: Mainstream researchers teamed with co-researchers from the Wikwemikong Unceded Indian Reserve for 5 years. Community meetings and talking circles were employed as culturally sensitive data collection techniques to uncover how to encourage youth participation in Wikwemikong’s sport programs. The overarching methodology for the project is PAR. Results: Themes and subthemes were determined by community consensus with terms indigenous (ie, culturally relevant) among the local Aboriginal culture. Family was considered important for youth involvement in Aboriginal community sport programs. Parents were expected to support their children by managing schedules and priorities, providing transportation, financial support, encouragement, and being committed to the child’s activity. Aunts, uncles, cousins, siblings, grandparents, and the family as a whole were seen as sharing the responsibility to retain youth in sport through collateral support (ie, when gaps in parental support arose). Conclusions: Suggestions are proposed regarding how families in Aboriginal communities can collaborate to facilitate sport and physical activity among their youth. Further suggestions are proposed for researchers engaging in culturally reflexive research with participants and coresearchers from oppressed cultures

    The use of an automated flight test management system in the development of a rapid-prototyping flight research facility

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    An automated flight test management system (ATMS) and its use to develop a rapid-prototyping flight research facility for artificial intelligence (AI) based flight systems concepts are described. The ATMS provides a flight test engineer with a set of tools that assist in flight planning and simulation. This system will be capable of controlling an aircraft during the flight test by performing closed-loop guidance functions, range management, and maneuver-quality monitoring. The rapid-prototyping flight research facility is being developed at the Dryden Flight Research Facility of the NASA Ames Research Center (Ames-Dryden) to provide early flight assessment of emerging AI technology. The facility is being developed as one element of the aircraft automation program which focuses on the qualification and validation of embedded real-time AI-based systems
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