1,892 research outputs found
Study of Lyndon B. Johnson Space Center utility systems
The results of an engineering study of potential energy saving utility system modifications for the NASA Lyndon B. Johnson Space Center are presented. The objective of the study was to define and analyze utility options that would provide facility energy savings in addition to the approximately 25 percent already achieved through an energy loads reduction program. A systems engineering approach was used to determine total system energy and cost savings resulting from each of the ten major options investigated. The results reported include detailed cost analyses and cost comparisons of various options. Cost are projected to the year 2000. Also included are a brief description of a mathematical model used for the analysis and the rationale used for a site survey to select buildings suitable for analysis
CREATING SPECIAL OPERATIONS FORCES' ORGANIC SMALL UNMANNED AIRCRAFT SYSTEM OF THE FUTURE
Emerging observations of the Ukrainian conflict reinforce standing assumptions that the future’s multidomain operational environment in which U.S. special operations forces (SOF) will deploy will be characterized by rapid, continuous advancements in intelligence, surveillance, and reconnaissance (ISR) technologies. The Department of Defense’s inability to develop and field innovative weapons and technical systems at the rate of its peer and near-peer competitors invites great risks to both its military members and its national security. One critical deficiency that U.S. SOF must address immediately is its use of artificial intelligence and machine learning in a small unmanned aircraft system (sUAS). We can no longer assume that we will achieve the air superiority or air parity that have enabled the persistent presence of theater-level assets to support military elements in contested and denied areas. This thesis focuses on enhancing U.S. SOF force protection and situational awareness by combining a cutting-edge sUAS with object recognition software to create an organic ISR capability. Following several field experiments in partnership with private industries to test and refine object recognition software when combined with a sUAS, our results strongly suggest that integrating object recognition capabilities into a SOF element’s organic sUAS can achieve the performance parameters necessary to fill the current gap in U.S. SOF force protection and ISR requirements.SOCOM S&TOffice of Naval ResearchMajor, United States ArmyApproved for public release. Distribution is unlimited
Feedback controlled optics with wavefront compensation
The sensitivity model of a complex optical system obtained by linear ray tracing is used to compute a control gain matrix by imposing the mathematical condition for minimizing the total wavefront error at the optical system's exit pupil. The most recent deformations or error states of the controlled segments or optical surfaces of the system are then assembled as an error vector, and the error vector is transformed by the control gain matrix to produce the exact control variables which will minimize the total wavefront error at the exit pupil of the optical system. These exact control variables are then applied to the actuators controlling the various optical surfaces in the system causing the immediate reduction in total wavefront error observed at the exit pupil of the optical system
MIUS integration and subsystems test program
The MIUS Integration and Subsystems Test (MIST) facility at the Lyndon B. Johnson Space Center was completed and ready in May 1974 for conducting specific tests in direct support of the Modular Integrated Utility System (MIUS). A series of subsystems and integrated tests was conducted since that time, culminating in a series of 24-hour dynamic tests to further demonstrate the capabilities of the MIUS Program concepts to meet typical utility load profiles for a residential area. Results of the MIST Program are presented which achieved demonstrated plant thermal efficiencies ranging from 57 to 65 percent
General MACOS Interface for Modeling and Analysis for Controlled Optical Systems
The General MACOS Interface (GMI) for Modeling and Analysis for Controlled Optical Systems (MACOS) enables the use of MATLAB as a front-end for JPL s critical optical modeling package, MACOS. MACOS is JPL s in-house optical modeling software, which has proven to be a superb tool for advanced systems engineering of optical systems. GMI, coupled with MACOS, allows for seamless interfacing with modeling tools from other disciplines to make possible integration of dynamics, structures, and thermal models with the addition of control systems for deformable optics and other actuated optics. This software package is designed as a tool for analysts to quickly and easily use MACOS without needing to be an expert at programming MACOS. The strength of MACOS is its ability to interface with various modeling/development platforms, allowing evaluation of system performance with thermal, mechanical, and optical modeling parameter variations. GMI provides an improved means for accessing selected key MACOS functionalities. The main objective of GMI is to marry the vast mathematical and graphical capabilities of MATLAB with the powerful optical analysis engine of MACOS, thereby providing a useful tool to anyone who can program in MATLAB. GMI also improves modeling efficiency by eliminating the need to write an interface function for each task/project, reducing error sources, speeding up user/modeling tasks, and making MACOS well suited for fast prototyping
The End of a Love Affair.
Music notes; Red backgroundhttps://scholarsjunction.msstate.edu/cht-sheet-music/10436/thumbnail.jp
Structural change within versus across firms: evidence from the United States
We document the role of intangible capital in manufacturing firms' substantial contribution to non-manufacturing employment growth from 1977-2019. Exploiting data on firms' "auxiliary" establishments, we develop a novel measure of proprietary in-house knowledge and show that it is associated with increased growth and industry switching. We rationalize this reallocation in a model where firms combine physical and knowledge inputs as complements, and where producing the latter in-house confers a sector-neutral productivity advantage facilitating within-firm structural transformation. Consistent with the model, manufacturing firms with auxiliary employment pivot towards services in response to a plausibly exogenous decline in their physical input prices
What factors increase the vulnerability of native birds to the impacts of alien birds?
Biodiversity impacts caused by alien species can be severe, including those caused by alien birds. In order to protect native birds, we aimed to identify factors that influence their vulnerability to the impacts of alien birds. We first reviewed the literature to identify native bird species sustaining such impacts. We then assigned impact severity scores to each native bird species, depending on the severity of the impacts sustained, and performed two types of analyses. First, we used contingency table tests to examine the distribution of impacts across their severity, type and location, and across native bird orders. Second, we used mixed‐effects models to test factors hypothesised to influence the vulnerability of native birds to the impacts of alien birds.
Ground‐nesting shorebirds and seabirds were more prone to impacts through predation, while cavity‐nesting woodpeckers and parrots were more prone to impacts through competition. Native bird species were more vulnerable when they occupied islands, warm regions, regions with climatic conditions similar to those in the native range of the invading alien species, and when they were physically smaller than the invading alien species. To a lesser extent, they were also vulnerable when they shared habitat preferences with the invading alien species.
By considering the number and type of native bird species affected by alien birds, we demonstrate predation impacts to be more widespread than previously indicated, but also that damaging predation impacts may be underreported. We identify vulnerable orders of native birds, which may require conservation interventions; characteristics of native birds that increase their vulnerability, which may be used to inform risk assessments; and regions where native birds are most vulnerable, which may direct management interventions. The impacts sustained by native birds may be going unnoticed in many regions of the world: there is a clear need to identify and manage them
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